Halogen-free flame retardant compositions and their use

Abstract

The application discloses a halogen-free flame retardant composition and application thereof in glass fiber reinforced engineering plastic flame retardation. The halogen-free flame retardant composition comprises, in percentage by mass, 1-99% of an ethyl butyl phosphinic acid aluminum-based phosphorus aluminum salt composite, 1-99% of aluminum phosphite and / or a derivative thereof, 0-80% of aluminum diethyl phosphinate, 0-40% of a nitrogen-containing compound, and 0-20% of a zinc salt thermal stabilizing compound. The halogen-free flame retardant composition is applied to glass fiber reinforced engineering plastic flame retardation and has a low forming shrinkage feature. The halogen-free flame retardant glass fiber reinforced engineering plastic prepared by using the halogen-free flame retardant composition can reach the UL94V-0 flame retardation standard.

Description

Technical Field

[0001] This invention relates to the field of new materials, specifically to a halogen-free flame retardant composition and its application. The core component of the halogen-free flame retardant composition is a phosphorus-containing aluminum salt composite based on ethyl butyl phosphinate (hereinafter referred to as phosphorus-containing aluminum salt composite or composite). It is particularly suitable for halogen-free flame retardancy of glass fiber reinforced engineering plastics, with the aim of obtaining halogen-free flame retardant materials with low shrinkage. Background Technology

[0002] Glass fiber reinforced engineering plastics (such as various nylons and polyesters) are widely used in the electronics and electrical appliance industries due to their excellent rigidity and impact resistance, low warpage, and good surface appearance. These applications require flame retardancy, but most engineering plastics are flammable. When combined with glass fiber, the wicking effect of glass fiber makes these reinforced engineering plastics even more flammable. Therefore, flame retardancy needs to be addressed when using glass fiber reinforced engineering plastics in these fields, and the wicking effect makes flame retardancy even more challenging.

[0003] Flame retardancy for glass fiber reinforced engineering plastics includes two basic types of flame retardant systems: halogenated and non-halogenated systems. Halogenated flame retardant systems typically contain brominated flame retardants in combination with antimony trioxide. Numerous studies have shown that glass fiber reinforced engineering plastics containing brominated flame retardants produce dense smoke and harmful substances such as hydrogen bromide during combustion, which can cause asphyxiation. Therefore, developing safe, environmentally friendly, and halogen-free flame retardant systems for glass fiber reinforced engineering plastics has become a research hotspot. In recent years, novel halogen-free flame retardants or flame retardant systems for glass fiber reinforced engineering plastics have emerged.

[0004] Currently, the mainstream halogen-free flame retardants used in glass fiber reinforced engineering plastics are based on compound systems of aluminum diethylphosphonate, including synergistic effects between aluminum diethylphosphonate and nitrogen-containing compounds, such as the aluminum diethylphosphonate compounded with melamine polyphosphate (MPP) system, and the nitrogen-free aluminum diethylphosphonate compounded with aluminum phosphite system. These systems offer high flame retardancy, high temperature resistance, and no color issues, and are currently widely used. However, aluminum diethylphosphonate-based compound systems suffer from significant crystal transformation at around 179°C, which occurs during the cooling and setting stage of molding. The substantial volume shrinkage during this crystal transformation leads to large dimensional differences in the molded products. In applications requiring high dimensional stability, lower molding shrinkage rates are needed, which cannot be met in these cases. If aluminum diethylphosphonate did not undergo a crystal transformation, the molding shrinkage rate would be reduced, and the dimensional stability of the molded products would be improved. Therefore, in these applications, it is desirable that the crystal transformation of aluminum diethylphosphines can be adjusted, the crystal transformation temperature can be changed, the energy absorption during the crystal transformation process can be reduced, or the crystal transformation process can be eliminated altogether, thereby reducing the negative effects during application.

[0005] To address the negative impact of the crystal transformation of aluminum diethylphosphonate, it is necessary to develop new flame-retardant systems. Two main solutions exist: (1) using components that can replace aluminum diethylphosphonate, maintaining flame-retardant properties without the crystal transformation process, or with lower energy absorption during the crystal transformation process; (2) adding components that can regulate the crystal transformation of aluminum diethylphosphonate, altering its crystal transformation temperature, reducing energy absorption during the crystal transformation process, or even eliminating the crystal transformation altogether. However, no reports have been found regarding these two solutions. Summary of the Invention

[0006] To address the aforementioned technical problems and shortcomings in this field, this invention proposes a flame retardant composition (also referred to as a "flame retardant compound system") with a phosphorus-containing aluminum salt composite based on ethylbutylaluminum phosphinate as the core component. This phosphorus-containing aluminum salt composite has an adjustable crystal transformation process, a lower crystal transformation temperature, and lower energy absorption during the crystal transformation process; under certain conditions, the crystal transformation process is absent. Furthermore, when compounded with diethylaluminum phosphinate, it can significantly affect the crystal transformation of diethylaluminum phosphinate, lowering the crystal transformation temperature and reducing energy absorption during the crystal transformation process; under certain conditions, the crystal transformation of diethylaluminum phosphinate disappears. Moreover, regarding flame retardant performance, when the phosphorus-containing aluminum salt composite replaces or is compounded with diethylaluminum phosphinate, the flame retardant performance of the entire compound system remains unaffected, thus meeting the requirements of applications in special fields with low shrinkage requirements.

[0007] The main objective of this invention is to provide a novel halogen-free flame-retardant compound system applicable to glass fiber reinforced engineering plastics, overcoming the defects of existing flame-retardant systems. This newly invented flame-retardant system enables the material to have a lower molding shrinkage rate while maintaining high flame retardancy.

[0008] This invention relates to the development of a novel halogen-free flame-retardant compound system applicable to glass fiber reinforced engineering plastics. It uses a phosphorus-containing aluminum salt composite based on ethylbutylaluminum phosphite as the core component, partially or completely replacing diethylaluminum phosphite. Through synergy with aluminum phosphite and / or its derivatives, and / or other nitrogen-containing compounds, zinc salt thermally stable compounds, etc., a synergistic flame-retardant compound system with lower crystal form transformation impact is formed, solving the negative impact of significant crystal form transformation during the processing of existing diethylaluminum phosphite-based flame-retardant systems. This novel flame-retardant system is well-suited for glass fiber reinforced engineering plastics, resulting in halogen-free flame-retardant materials with lower molding shrinkage.

[0009] The specific technical solution is as follows:

[0010] A halogen-free flame retardant composition, comprising, by weight percentage:

[0011]

[0012] The phosphorus-containing aluminum salt complex based on ethylbutylphosphinate aluminum comprises:

[0013] The phosphorus-containing structure of structural formula (I), and

[0014] One or more phosphorus-containing structures referred to by structural formula (II) and / or structural formula (III);

[0015]

[0016] In structural formula (II), R1 and R2 are each independently selected from H or C1-C6 alkyl groups, and when either R1 or R2 is ethyl, the other is not butyl;

[0017] In structural formula (III), R3 is H or a C1-C6 alkyl group.

[0018] The present invention aims to address the defects in the existing halogen-free flame retardant systems based on aluminum diethylphosphinate, which are widely used in glass fiber reinforced engineering plastics, due to the crystal transformation of aluminum diethylphosphinate. The inventors have conducted extensive and in-depth research on this issue.

[0019] Research has revealed that the aforementioned phosphorus-containing aluminum salt complex based on ethylbutylaluminum phosphinate exhibits a different crystal transformation than diethylaluminum phosphinate. Furthermore, under certain conditions, such as when the molar content of ethylbutylaluminum phosphinate in the complex is not less than 30%, the crystal transformation in the complex disappears. Moreover, this phosphorus-containing aluminum salt complex can adjust the crystal transformation of diethylaluminum phosphinate, reducing its crystal transformation temperature and energy absorption during the transformation, and even causing the crystal transformation of diethylaluminum phosphinate to disappear altogether.

[0020] The phosphorus-containing aluminum salt complex of the present invention differs from single aluminum salts or mixtures of several aluminum salts, exhibiting different properties and being a compound with a novel structure.

[0021] In a preferred embodiment, the phosphorus-containing aluminum salt complex based on ethylbutylphosphinic acid aluminum has the structure shown in formula (IV):

[0022]

[0023] In formula (IV), a, b, c, d, and e are all molar ratios, a is 0.01-0.99, b, c, d, and e are 0-0.99 and not all 0 at the same time, a+b+c+d+e=1, R1 and R2 are independently selected from C1-C6 alkyl groups, and when either R1 or R2 is ethyl, the other is not ethyl or butyl, and R3 is a C1-C6 alkyl group.

[0024] Formula (IV) represents a preferred complex formed by ethylbutylaluminum phosphite with other phosphorus-containing aluminum salts, including diethylaluminum phosphite, a dialkylaluminum phosphite other than ethylbutylaluminum phosphite and diethylaluminum phosphite, a monoalkylaluminum phosphite, an inorganic aluminum phosphite, etc., forming the phosphorus-containing aluminum salt complex of the present invention. Ethylbutylaluminum phosphite can form aluminum salt complexes with one or more of these phosphorus-containing aluminum salts.

[0025] Further optimization is that in formula (IV), the larger a is, the greater the ability to regulate the crystal transformation of the complex, and the preferred value of a is 0.2-0.99.

[0026] The present invention also provides a preferred preparation method of the aforementioned phosphorus-containing aluminum salt complex, comprising the following steps:

[0027] (1) Ethyl butyl phosphonic acid and / or soluble ethyl butyl phosphonate containing the anionic moiety of structural formula (I) and other acids and / or soluble salts (phosphorus-containing complex anion donors) containing the anionic moiety of structural formula (II) and / or structural formula (III) are dissolved in water (a small amount of strong acid may be added to the water or no strong acid may be added), and then an aluminum-containing compound (aluminum ion donor) is added, and the reaction is carried out at 80-90℃.

[0028] (2) After the reaction is completed, the solid is separated from the liquid, washed and dried, and then treated at high temperature at 180-450℃ to obtain the phosphorus-aluminum salt complex.

[0029] In the above preparation method:

[0030] The soluble salts mentioned are usually sodium or potassium salts;

[0031] The aluminum-containing compound is preferably at least one of aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum hydroxide, and aluminum oxide;

[0032] The preferred endpoint of the washing process is when the conductivity of the effluent is less than 500 μs / cm.

[0033] In step (1), the phosphorus-containing composite anion donor and the aluminum ion donor can be added in an equimolar ratio to achieve complete reaction.

[0034] In step (1), the strong acid includes concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid, and concentrated phosphoric acid, and the amount added can be 2%-5% of the mass of the phosphorus-containing complex anion donor.

[0035] When the aluminum-containing compound is insoluble in water, it can be dispersed in water to form a suspension dispersion system. In this case, it can react with the phosphorus-containing complex anion donor added in the form of acid without the need for a high concentration of strong acid. When the aluminum-containing compound is water-soluble, it is recommended to react in the presence of a high concentration of strong acid. In this case, it can react with the phosphorus-containing complex anion donor added in the form of salt.

[0036] The mass concentration of the aluminum-containing compound in the reaction system is preferably 15%-50%.

[0037] In step (1), the reaction time can be 1-5 hours.

[0038] In step (2):

[0039] After the reaction is complete, a solid precipitate can be obtained by controlling the pH of the liquid phase to be less than 4; pH control can be achieved by adding alkali or metal oxides, etc.

[0040] The drying process can employ various ovens, drying rooms, dryers, etc., with a drying temperature of 100-130℃. High-temperature treatment is a crucial step in the preparation process. The treatment process is related to the composition and proportion of the phosphorus-aluminum salt composite, as well as the processing volume. The temperature setting for high-temperature treatment is a key factor. Studies have found that when the treatment temperature is below 180℃, the phosphorus-aluminum salt composite of this application cannot be obtained. The upper limit of the high-temperature treatment temperature is the decomposition temperature of the composite, typically below 450℃. The high-temperature treatment process involves raising the temperature to 180-450℃ over 0.5-10 hours for high-temperature treatment, with a treatment time of 1-300 minutes.

[0041] The high-temperature treatment process in step (2) can also be carried out in an inert atmosphere (nitrogen atmosphere, rare gas atmosphere, etc.) or under vacuum conditions.

[0042] After step (2), the obtained phosphorus-aluminum salt composite can be pulverized to the required particle size as needed.

[0043] Research has found that in order to obtain the phosphorus-aluminum salt composite of the present invention, both steps in the preparation method are essential. That is, the phosphorus-aluminum salt composite of the present application cannot be obtained without high-temperature treatment (including treatment temperature below 180°C) or by simply dry mixing several phosphorus-aluminum salts and then heat-treating them at high temperature.

[0044] The phosphorus-containing aluminum salt complex of the present invention was characterized by DSC (differential scanning calorimetry). As shown in... Figure 1 Taking the ethylbutylaluminum phosphite (0.7)-diethylaluminum phosphite (0.3) complex (the numbers indicate the molar ratio of the complex aluminum salts, the same below) as an example, its DSC graph is as follows. Figure 2 As shown in the DSC diagram, this ethylbutylaluminum phosphite-diethylaluminum phosphite complex does not exhibit a crystal transformation peak. Figure 3 This is the DSC chart of a mixture of aluminum ethyl butyl phosphinate and aluminum diethyl phosphinate (molar ratio 0.7:0.3). Figure 4 and Figure 5 The images show the DSC diagrams for aluminum ethylbutylphosphinate and aluminum diethylphosphinate, respectively. The results indicate that the product prepared according to the method of this invention is... Figure 1 The composite structure shown is different from the mixture of the two. In the mixture, its DSC reflects the characteristics of a mixture, with the crystal transformation temperature being the same as that of aluminum diethylphosphinate. Due to the decrease in proportion, the enthalpy of the crystal transformation decreases. However, in the composite, at the same proportion, the characteristic crystal transformation peak of aluminum diethylphosphinate disappears. Therefore, the composite salt is not a mixture of the two, but a new structure.

[0045] DSC results show that aluminum diethylphosphinate exhibits a significant crystal transformation. Among phosphorus-containing aluminum complexes based on ethylbutylphosphinate, the ethylbutylphosphinate (0.05)-diethylphosphinate (0.95) complex has a lower crystal transformation temperature and heat endothermic reaction (see [link to DSC results]). Figure 6 The ethylbutylaluminum phosphite (0.7)-diethylaluminum phosphite (0.3) complex showed no crystal transformation according to DSC results. These phosphorus-containing aluminum salt complexes can obviously overcome the negative effects of the crystal transformation of diethylaluminum phosphite and may replace diethylaluminum phosphite.

[0046] Further research revealed that the phosphorus-containing aluminum salt composite of the present invention, under certain conditions, still exhibits good flame retardant properties when used to replace aluminum diethylphosphinate, including when used in synergy with other non-crystalline systems, while simultaneously resolving the crystal transformation problem of aluminum diethylphosphinate. Although aluminum ethylbutylphosphinate also does not exhibit crystal transformation, its phosphorus content (19.6%) is significantly lower than that of aluminum diethylphosphinate (23.8%), and phosphorus content is a crucial indicator for evaluating phosphorus-based flame retardants; therefore, it cannot completely replace aluminum diethylphosphinate.

[0047] The phosphorus-aluminum salt composite of the present invention is characterized by the absence of crystal form transformation, or even if crystal form transformation is present, its crystal form transformation has low endothermic characteristics and a lower crystal form transformation temperature, and has a high phosphorus content. The phosphorus-aluminum salts involved in the composite exhibit synergistic effects, good flame retardancy, a high initial decomposition temperature, low water solubility, and resistance to migration and moisture absorption. It can be used as a flame retardant in engineering plastics such as nylon and PBT (polybutylene terephthalate), especially in glass fiber reinforced engineering plastics. In some applications, it is necessary to compound it with synergists to improve flame retardant performance and achieve better flame retardant effects.

[0048] The inventors discovered through research that this phosphorus-containing aluminum salt complex, in synergy with aluminum phosphite and its derivatives, can further improve its flame-retardant properties, exhibiting excellent synergy. These aluminum phosphite and its derivatives should be amorphous transformations. Figure 7 This is a DSC result for aluminum phosphite. The aluminum phosphite and its derivatives include aluminum phosphite, aluminum hydrogen phosphite, aluminum pyrophosphite, and aluminum phosphite-based complexes.

[0049] Studies have found that nitrogen-containing compounds can also be added as synergistic components to the synergistic system formed by phosphorus-containing aluminum salt complexes and aluminum phosphite and its derivatives to meet the flame retardant requirements of certain applications. These nitrogen-containing compounds do not undergo crystalline transformation. Figure 8 The results are DSC values ​​for MPP without crystalline transformation. The nitrogen-containing compounds include MPP (melamine polyphosphate) and MCA (melamine cyanurate).

[0050] Studies have found that diethylphosphinate aluminum can also be added to the synergistic system formed by phosphorus-containing aluminum salt complexes and aluminum phosphite and its derivatives. Specifically, this compensates for the decrease in phosphorus content caused by excessively high ethylbutylphosphinate aluminum content in the complex, producing a synergistic effect and meeting the flame-retardant requirements of certain applications. Diethylphosphinate aluminum exhibits a significant crystal transformation, but the phosphorus-containing aluminum salt complex can regulate this transformation, reducing energy absorption and the crystal transformation temperature, and even eliminating the crystal transformation of diethylphosphinate aluminum. This also reduces the impact of the crystal transformation and lowers the molding shrinkage rate of the material. Figure 9 and Figure 10The DSC results are for phosphorus-containing composite aluminum salts (ethylbutylaluminum phosphonate (0.7)-diethylaluminum phosphonate (0.3) composite) and a mixture of diethylaluminum phosphonate, respectively.

[0051] Furthermore, it was found that a small amount of high-temperature resistant, non-precipitating zinc salt thermally stable compounds can be introduced into the synergistic system formed by the phosphorus-containing aluminum salt complex and aluminum phosphite and its derivatives. This further improves corrosion resistance and flame retardancy, without any precipitation issues. These zinc salt thermally stable compounds do not undergo crystal transformation. Figure 11 The results are DSC values ​​for zinc borate without crystalline transformation. Thermally stable zinc salts include zinc borate and zinc stannate; anhydrous zinc salts exhibit high decomposition temperatures, low water solubility, and do not migrate or precipitate.

[0052] Based on the above research, the following preferred technical solutions can be proposed for this invention:

[0053] The average particle size D50 of the phosphorus-containing aluminum salt complex based on ethylbutylphosphonate aluminum satisfies 5μm < D50 < 50μm;

[0054] The aluminum phosphite and / or its derivatives have no crystal transformation characteristics, and the average particle size D50 satisfies 5μm < D50 < 50μm;

[0055] The average particle size D50 of the aluminum diethylphosphonate satisfies 5μm < D50 < 50μm;

[0056] The nitrogen-containing compound has no crystal transformation characteristics, including at least one of MPP, MCA, triazine compounds, etc., and the average particle size D50 satisfies 5μm < D50 < 50μm;

[0057] The zinc salt heat-stabilized compound has no crystal transformation characteristics, including at least one of zinc borate, zinc oxide, zinc stannate, etc., with an average particle size D50 satisfying 5μm < D50 < 50μm, and its mass percentage in the halogen-free flame retardant composition is 0-10%.

[0058] The halogen-free flame retardant composition may further include at least one of the following components (A)-(C):

[0059] (A) One or more non-complex salts of ethyl butyl phosphinate, butyl butyl phosphinate, ethyl hexyl phosphinate, butyl hexyl phosphinate, and hexyl hexyl phosphinate;

[0060] (B) Alkylphosphonates;

[0061] (C) One or more of the following: sulfate, chloride, phosphate, phosphite, hypophosphite, nitrate, acetate, ammonium salt, iron-containing compound, calcium-containing compound, magnesium-containing compound, titanium-containing compound, sodium-containing compound, and potassium-containing compound.

[0062] The present invention also provides the application of the halogen-free flame retardant composition in flame retardancy of glass fiber reinforced engineering plastics.

[0063] The glass fiber reinforced engineering plastic can use at least one of glass fiber reinforced nylon, polyester, POK (polyketone) as the polymer matrix.

[0064] The halogen-free flame retardant composition is a functional additive that imparts flame retardant properties to glass fiber reinforced engineering plastics. To meet the relevant standard requirements, based on the total mass of the glass fiber reinforced engineering plastics (100%), the addition amount of the halogen-free flame retardant composition is preferably 5% to 40%. The glass fiber reinforced engineering plastics achieve a flame retardant rating of UL94 V-0 and have low molding shrinkage.

[0065] The glass fiber reinforced engineering plastic can also be a thin-walled product, and can meet the UL94 V-0 flame retardant standard with a thickness as low as 0.4 mm.

[0066] To prepare halogen-free flame-retardant glass fiber reinforced materials, the flame-retardant system needs to be uniformly dispersed in the material. This can be achieved by using a twin-screw extruder with a glass fiber inlet and a flame retardant powder inlet, where the various components are melt-blended and then extruded and granulated.

[0067] The main advantages of this invention compared to existing technologies include:

[0068] The multi-component synergistic flame retardant system based on phosphorus-aluminum salt composite provided by this invention overcomes the defects of existing flame retardant systems. It can be used as a halogen-free flame retardant system for glass fiber reinforced engineering plastics, reduces the molding shrinkage rate of the material, and can be used to prepare novel low-shrinkage halogen-free flame retardant glass fiber reinforced special materials. Attached Figure Description

[0069] Figure 1 The molecular structure is that of an aluminum (0.7)-diethyl butyl phosphinate complex;

[0070] Figure 2 for Figure 1 The DSC diagram of the ethylbutylaluminum phosphite-diethylaluminum phosphite complex is shown below.

[0071] Figure 3 DSC chromatogram of a mixture of aluminum ethyl butyl phosphinate and aluminum diethyl phosphinate (molar ratio 0.7:0.3);

[0072] Figure 4 DSC diagram of aluminum ethylbutylphosphinate;

[0073] Figure 5 DSC diagram of aluminum diethylphosphinate;

[0074] Figure 6 DSC diagram of the aluminum ethyl butyl phosphite (0.05)-diethyl aluminum phosphite (0.95) complex;

[0075] Figure 7 DSC diagram of aluminum phosphite without amorphous transformation;

[0076] Figure 8 DSC plot of MPP without crystallization transformation;

[0077] Figure 9 DSC chart of aluminum diethylphosphonate with 8% (based on the total mass of the aluminum phosphorus salt complex and aluminum diethylphosphonate being 100%) added;

[0078] Figure 10 DSC chart of aluminum diethylphosphonate with 30% (based on the total mass of the aluminum phosphorus salt complex and aluminum diethylphosphonate being 100%) added;

[0079] Figure 11 This is the DSC diagram of zinc borate without crystalline transformation. Detailed Implementation

[0080] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0081] like Figure 1 Synthesis of the ethylbutylaluminum phosphite (0.7)-diethylaluminum phosphite (0.3) complex with the shown molecular structure

[0082] The preparation process is as follows: In a 2L reactor, 120.4g (0.7mol) of sodium ethylbutylphosphonate and 43.2g (0.3mol) of sodium diethylphosphonate were dissolved in 381.7g of water and stirred thoroughly to obtain a mixed solution of sodium ethylbutylphosphonate and sodium diethylphosphonate. In a 500mL beaker, 57g of aluminum sulfate was dissolved in 133g of water, and then 4.0g of 98wt% concentrated sulfuric acid was added to the aluminum sulfate solution and stirred thoroughly to mix evenly. The mixture was then transferred to a dropping funnel. The reactor was heated to 90℃, and the aluminum sulfate solution containing sulfuric acid was added dropwise. The addition was completed in 2 hours, and the reaction was continued at this temperature for another hour. The mixture was filtered while hot, and the precipitate was washed several times until the conductivity of the washing water was less than 200μS / cm, at which point the washing was stopped. The material was transferred to an oven, heated to 120℃, and dried for 60 min until the solid moisture content was 0.1 wt%. The temperature was then increased to 180℃ at a rate of 2℃ / min and held for 60 min. Next, the temperature was increased to 320℃ at a rate of 1℃ / min and held for 30 min. The material was then cooled to room temperature and discharged to obtain an ethylbutylaluminum phosphite (0.7)-diethylaluminum phosphite (0.3) composite, denoted as Composite-1. The material was pulverized, with an average particle size D50 of 42 μm and a yield of 96.5%. The crystal transformation of the sample was tested by DSC, and the test results are as follows: Figure 2 As shown.

[0083] By referring to the above preparation process, other composites can be obtained by changing the types of raw materials and the molar ratio of the raw materials.

[0084] In the flame retardant systems involved in the following embodiments and comparative examples:

[0085] Complex-1: Aluminum ethylbutylphosphinic acid (0.7)-aluminum diethylphosphinic acid (0.3) complex, DSC results are as follows. Figure 2 As shown;

[0086] Complex-2: Aluminum ethylbutylphosphinic acid (0.05)-aluminum diethylphosphinic acid (0.95) complex, DSC results are as follows. Figure 6 As shown;

[0087] Complex-3: Aluminum ethylbutylphosphinate (0.7)-aluminum diethylphosphinate (0.2)-aluminum ethylhexylphosphinate (0.1) complex;

[0088] Complex-4: Aluminum ethylbutylphosphite (0.7)-aluminum diethylphosphite (0.2)-aluminum phosphite (0.1) complex;

[0089] Complex-5: Aluminum ethylbutylphosphinic acid (0.7)-aluminum diethylphosphinic acid (0.2)-aluminum ethylphosphinic acid (0.1) complex;

[0090] Complex-6: Aluminum ethylbutylphosphite (0.7)-aluminum diethylphosphite (0.15)-aluminum ethylhexylphosphite (0.1)-aluminum phosphite (0.05) complex;

[0091] Complex-7: Aluminum ethylbutylphosphinate (0.7)-aluminum diethylphosphinate (0.15)-aluminum ethylhexylphosphinate (0.1)-aluminum ethylphosphinate (0.05) complex;

[0092] Complex-8: Aluminum ethylbutylphosphite (0.7)-aluminum diethylphosphite (0.15)-aluminum ethylphosphite (0.1)-aluminum phosphite (0.05) complex;

[0093] Complex-9: A complex of aluminum ethylbutylphosphite (0.7)-aluminum diethylphosphite (0.1)-aluminum ethylhexylphosphite (0.1)-aluminum ethylphosphite (0.05)-aluminum phosphite (0.05), denoted as Complex-9;

[0094] The DSC results of aluminum diethylphosphinate are as follows: Figure 5 As shown;

[0095] DSC results for aluminum phosphite are as follows Figure 7 As shown;

[0096] The DSC results of MPP are as follows Figure 8 As shown;

[0097] DSC results of zinc borate as follows Figure 11 As shown.

[0098] Unless otherwise specified, all material quantities in the embodiments and comparative examples are parts by mass.

[0099] Example 1

[0100] The performance of the flame retardant was investigated by applying the compounded flame retardant system to glass fiber reinforced nylon according to the following steps and test methods.

[0101] 1) Blending of halogen-free flame retardant systems

[0102] Add the components of the compound flame retardant system to the high-speed mixer according to the proportions in Table 1, start the high-speed mixer, stir for 10 minutes to complete the mixing of the halogen-free flame retardant system, discharge the material, perform DSC testing, and set aside for use.

[0103] 2) Extrusion granulation of materials

[0104] Set the temperatures of each zone of the twin-screw extruder to the predetermined temperatures. After the temperatures stabilize for 20 minutes, add the nylon system from the hopper, add glass fiber through the glass fiber inlet, and add flame retardant powder through the powder feeding hole. Start the main extruder and feeder to complete the extrusion granulation of the material. The granulated material is then conveyed into the silo via a pneumatic conveying system and dried.

[0105] 3) Application and testing of materials

[0106] The dried material is injection molded into standard samples as specified by various testing standards in an injection molding machine, and the relevant material properties are tested.

[0107] The materials and proportions in this embodiment are shown in Table 1, and the material test results are also shown in Table 1.

[0108] Example 2

[0109] The implementation process was the same as in Example 1. The flame retardant system consisted of aluminum phosphate salt complex-1, aluminum phosphite, and MPP, with the total amount of the flame retardant system remaining constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0110] Example 3

[0111] The implementation process was the same as in Example 1. The flame retardant system consisted of aluminum phosphate salt complex-1, aluminum phosphite, MPP, and zinc borate, with the total amount of the flame retardant system remaining constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0112] Example 4

[0113] The implementation process was the same as in Example 1. The flame retardant system consisted of aluminum phosphate salt complex-1, aluminum diethylphosphinate, and aluminum phosphite, with the total amount of the flame retardant system remaining constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0114] Comparative Example 1

[0115] The implementation process was the same as in Example 1, except that the flame retardant system used only the single component containing phosphorus aluminum salt composite-1. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0116] Comparative Example 2

[0117] The implementation process was the same as in Example 1, except that the flame retardant system used was a compound system of aluminum diethylphosphinate and aluminum phosphite. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0118] Comparative Example 3

[0119] The implementation process was the same as in Example 1, except that the flame retardant system used only aluminum diethylphosphinate as a single component. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0120] Comparative Example 4

[0121] The implementation process was the same as in Example 1, except that the flame retardant system used a mixture of aluminum ethyl butyl phosphinate and aluminum diethyl phosphinate in the same proportion to replace composite-1. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0122] Comparative Example 5

[0123] The implementation process was the same as in Example 1, except that the flame retardant system used was a compound system of aluminum ethyl butyl phosphite and aluminum phosphite. Other materials and proportions are shown in Table 1, and the material results are also shown in Table 1.

[0124] The test conditions for each performance indicator in Tables 1, 2, and 3 are as follows:

[0125] 1. DSC test method for the powder properties of flame retardant system: nitrogen atmosphere; heating rate: 10℃ / min; temperature range: room temperature - 300℃.

[0126] 2. Flame retardant properties of materials

[0127] Tested according to UL94 testing standards (test piece thickness 0.4mm). Based on UL94 flame retardancy performance, the following levels are assigned:

[0128] V-0: Afterburning for no more than 10 seconds after each ignition, a total of 5 samples were ignited, each sample was ignited twice, the total afterburning time of the 5 samples for 10 ignitions was no more than 50 seconds, there was no burning drip, the sample was not completely burned, and there was no smoldering of the sample for more than 30 seconds after the ignition ended.

[0129] V-1: Afterburning for no more than 30 seconds after each ignition, a total of 5 samples are ignited, each sample is ignited twice, the total afterburning time of 10 ignitions for 5 samples is no more than 250 seconds, there is no burning drip, the sample is not completely burned, and there is no smoldering of the sample for more than 60 seconds after ignition ends.

[0130] V-2: Ignition of cotton by burning drippings; other standards are the same as V-1.

[0131] The test here only focuses on whether V-0 is reached. If it is reached, it is marked as PASS; otherwise, it is marked as FAIL.

[0132] Flame retardancy testing is related to thickness; here we examine the thinnest sample thickness, which is 0.4 mm.

[0133] 3. Material molding shrinkage: Tested according to the method specified in ASTM D955-2008.

[0134] Table 1

[0135]

[0136] The results show that the material using the phosphorus-containing aluminum salt composite exhibits lower molding shrinkage than diethyl aluminum phosphinate, and also lower than the mixture of ethyl butyl aluminum phosphinate and diethyl aluminum phosphinate in the same proportion. For the PA66 system, the combination of phosphorus-containing aluminum composite with a synergist results in higher flame retardancy while also achieving lower molding shrinkage.

[0137] Example 5

[0138] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-3, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0139] Example 6

[0140] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-4, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0141] Example 7

[0142] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-5, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0143] Example 8

[0144] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-6, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0145] Example 9

[0146] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-7, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0147] Example 10

[0148] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-8, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0149] Example 11

[0150] The implementation process was the same as in Example 1, with the flame retardant system being phosphorus-aluminum salt composite-9, maintaining the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0151] Table 2

[0152]

[0153] The results in Table 2 show that the multi-phosphorus aluminum salt composite based on ethylbutylphosphonate, in conjunction with a synergist, exhibits low molding shrinkage and good flame retardant properties when applied to nylon materials.

[0154] Example 12

[0155] The implementation process was the same as in Example 1, except that a small amount of aluminum ethyl butyl phosphinate was added to the flame retardant system to keep the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 3, and the resulting material results are also shown in Table 3.

[0156] Example 13

[0157] The implementation process was the same as in Example 1, except that a small amount of aluminum ethyl phosphonate was added to the flame retardant system to keep the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 3, and the material results are also shown in Table 3.

[0158] Example 14

[0159] The implementation process was the same as in Example 1, except that a small amount of aluminum phosphate was added to the flame retardant system to keep the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 3, and the resulting material results are also shown in Table 3.

[0160] Table 3

[0161]

[0162] The results in Table 3 show that the presence of a small amount of other non-composite salts in the flame retardant components of this application does not affect the molding shrinkage rate and flame retardant effect of this application.

[0163] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A halogen-free flame retardant composition, characterized in that, Its composition, by weight percentage, includes: Phosphorus-containing aluminum salt complexes based on ethylbutylphosphinic acid aluminum (1%–99%) Aluminum phosphite and / or its derivatives, 1%~99%, Aluminum diethylphosphinate 0~80%, Nitrogen compounds 0-40%, Zinc salt heat-stabilized compounds: 0-20%; The phosphorus-containing aluminum salt complex based on ethylbutylphosphinate aluminum comprises: The phosphorus-containing structure of structural formula (I), and One or more phosphorus-containing structures referred to by structural formula (II) and / or structural formula (III); In structural formula (II), R1 and R2 are each independently selected from H or C1-C6 alkyl groups, and when either R1 or R2 is ethyl, the other is not butyl; In structural formula (III), R3 is H or a C1-C6 alkyl group; The preparation method of the phosphorus-containing aluminum salt complex includes the following steps: (1) Ethyl butyl phosphonic acid and / or soluble ethyl butyl phosphonate containing the anionic moiety of structural formula (I) are dissolved in water with other acids and / or soluble salts containing the anionic moiety of structural formula (II) and / or structural formula (III) participating in the complex, and then aluminum-containing compounds are added and reacted at 80-90℃. (2) After the reaction is completed, the solid is separated from the liquid, washed and dried, and then treated at high temperature at 180-450℃ to obtain the phosphorus-aluminum salt complex.

2. The halogen-free flame retardant composition according to claim 1, characterized in that, The phosphorus-containing aluminum salt complex based on ethylbutylphosphonate aluminum has the structure shown in formula (IV): In formula (IV), a, b, c, d, and e are all molar ratios, a is 0.01-0.99, b, c, d, and e are 0-0.99 and not all 0 at the same time, a+b+c+d+e=1, R1 and R2 are independently selected from C1-C6 alkyl groups, and when either R1 or R2 is ethyl, the other is not ethyl or butyl, and R3 is a C1-C6 alkyl group.

3. The halogen-free flame retardant composition according to claim 2, characterized in that, In equation (IV), a is 0.2-0.

99.

4. The halogen-free flame retardant composition according to claim 1, characterized in that, The average particle size D50 of the phosphorus-containing aluminum salt complex based on ethylbutylphosphonate aluminum satisfies 5 μm < D50 < 50 μm.

5. The halogen-free flame retardant composition according to claim 1, characterized in that, The aluminum phosphite and / or its derivatives are free from crystalline transformation characteristics, including at least one of aluminum phosphite, aluminum hydrogen phosphite, aluminum metaphosphite, and aluminum phosphite-based complexes, with an average particle size D50 satisfying 5 μm < D50 < 50 μm.

6. The halogen-free flame retardant composition according to claim 1, characterized in that, The average particle size D50 of the aluminum diethylphosphonate satisfies 5 μm < D50 < 50 μm.

7. The halogen-free flame retardant composition according to claim 1, characterized in that, The nitrogen-containing compound does not exhibit crystal transformation characteristics. It includes at least one of MPP, MCA, and triazine compounds, with an average particle size D50 satisfying 5 μm < D50 < 50 μm.

8. The halogen-free flame retardant composition according to claim 1, characterized in that, The zinc salt heat-stabilized compound has no crystal transformation characteristics, including at least one of zinc borate, zinc oxide, and zinc stannate, with an average particle size D50 satisfying 5 μm < D50 < 50 μm, and a mass percentage of 0-10% in the halogen-free flame retardant composition.

9. The halogen-free flame retardant composition according to claim 1, characterized in that, The halogen-free flame retardant composition further includes at least one of the following components (A)-(C): (A) One or more non-complex salts of ethyl butyl phosphite, butyl butyl phosphite, ethyl hexyl phosphite, butyl hexyl phosphite, and hexyl hexyl phosphite; (B) Alkyl phosphonates; (C) One or more of the following: sulfate, chloride, phosphate, phosphite, hypophosphite, nitrate, acetate, ammonium salt, iron-containing compound, calcium-containing compound, magnesium-containing compound, titanium-containing compound, sodium-containing compound, and potassium-containing compound.

10. The application of the halogen-free flame retardant composition according to any one of claims 1 to 9 in flame retardancy of glass fiber reinforced engineering plastics, characterized in that, The glass fiber reinforced engineering plastic uses at least one of glass fiber reinforced nylon, polyester, and POK as the polymer matrix; Based on the total mass of the glass fiber reinforced engineering plastic as 100%, the amount of the halogen-free flame retardant composition added is 5% to 40%, and the flame retardant rating of the glass fiber reinforced engineering plastic reaches UL94 V-0.

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