Flame-retardant composition and thermoplastic flame-retardant polymer material, flame-retardant thermoplastic polyester composite comprising same

Abstract

The present application belongs to the technical field of high polymer materials, and particularly relates to a flame-retardant composition, a thermoplastic flame-retardant high polymer material containing the same, and a flame-retardant thermoplastic polyester composite material. The flame-retardant composition contains a dialkyl hypophosphite hybrid salt with a chemical formula shown in formula (I) and an acrylate compound, the content of the acrylate compound is 0.5-7 wt%, and formula (I). The dialkyl hypophosphite hybrid salt and the acrylate compound have a synergistic effect. When they are applied to a thermoplastic polyester, the flame-retardant efficiency of the composite material is significantly improved, and the impact resistance and processing fluidity of the material are simultaneously improved, thus breaking through the technical bottleneck that flame retardation, toughness and fluidity are mutually restricted in a traditional flame-retardant system.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to flame-retardant compositions and thermoplastic flame-retardant polymer materials containing them, and flame-retardant thermoplastic polyester composite materials. Background Technology

[0002] Thermoplastic polyesters possess excellent chemical resistance, electrical insulation, and processing fluidity. After modification with glass fiber reinforcement, their rigidity, heat resistance, and dimensional stability are further improved, making them widely used in precision components such as connectors, relays, and switch housings in the electronics and electrical appliance fields. However, while the introduction of glass fiber improves mechanical properties, it also brings some problems to glass fiber reinforced polyesters: (1) the "wick effect" caused by glass fiber will exacerbate the dripping phenomenon during combustion; (2) the glass fiber-resin interface will weaken the matrix's resistance to crack propagation, and the impact toughness will be significantly reduced compared to pure polyester; (3) glass fiber filling will significantly increase the viscosity of the system and deteriorate the processing fluidity. Therefore, the flame retardant modification of glass fiber reinforced polyesters needs to balance impact resistance and processing fluidity.

[0003] Currently, dialkyl phosphonates (represented by aluminum diethyl phosphonate (AlPi)) are the mainstream halogen-free flame-retardant system for glass fiber reinforced polyester. They achieve flame retardancy through a dual mechanism of gas-phase free radical capture and condensed-phase char formation. However, single dialkyl phosphonates are insufficient to meet the UL94 V-0 flame retardancy rating requirements. In practical applications, they often need to be combined with synergists such as melamine polyphosphate (MPP), zinc borate, and metal oxides to achieve the UL94 V-0 flame retardancy rating. For example, patent CN103140547A discloses the combined use of dialkyl phosphonates and melamine polyphosphate, along with the synergistic effect of zinc borate, zinc oxide, and zinc phosphate metal salts, to flame-retard glass fiber reinforced polybutylene terephthalate (PBT). Patent CN103154110A discloses the synergistic flame retardancy of dialkyl phosphonates, melamine polyphosphate, and phosphites in glass fiber reinforced PBT. However, these multi-component systems have revealed some deep technical defects in engineering practice: (1) Flame retardant efficiency and impact resistance are mutually exclusive: The total addition amount of AlPi / MPP / zinc borate usually needs to reach 20~25 wt%, and the high-filled inorganic particles agglomerate to form stress concentration points, and the notched impact strength is significantly deteriorated; (2) Flowability deterioration: Multi-component systems are prone to weakening the original flowability improvement effect of dialkylphosphinates, and the processing flowability is limited, making it difficult to meet the molding requirements of thin-walled precision injection molded parts; (3) Precipitation risk: MPP has poor compatibility with polyester matrix and is easy to migrate and precipitate in humid and hot environments, causing color difference and performance degradation.

[0004] To address the aforementioned shortcomings, traditional technical approaches often employ a "formulation stacking" strategy, which involves adding toughening agents to compensate for impact resistance while simultaneously introducing lubricants to compensate for deteriorated flowability. For example, patents CN121160048A and CN104945866A both use acrylate copolymers as toughening agents and are compounded with lubricants. However, this strategy has significant technical limitations: the introduction of macromolecular toughening agents may reduce flame retardant efficiency and worsen processing flowability. To restore the V-0 flame retardant rating, additional flame retardants are forced, further deteriorating flowability. Furthermore, there is a contradiction between the increase in flame retardant quantity and the toughening effect, preventing a simultaneous increase in impact strength. Therefore, flame retardant efficiency, impact resistance, and processing flowability form a mutually restrictive negative cycle, making it difficult to achieve simultaneous improvement in all three.

[0005] Therefore, there is an urgent need in this field to develop a novel flame retardant composition that can synergistically improve flame retardant efficiency, achieve high-efficiency flame retardancy at low addition levels, without compromising the impact resistance of the polyester matrix, and improve processing fluidity, thus breaking through the performance bottleneck of traditional systems. Summary of the Invention

[0006] In view of the above-mentioned problems existing in the prior art, the present invention provides a flame-retardant composition, a thermoplastic flame-retardant polymer material comprising the flame-retardant composition, and a flame-retardant thermoplastic polyester composite material comprising the flame-retardant composition. The flame-retardant composition can impart highly efficient flame-retardant properties to the composite material at a relatively low addition amount, and can significantly improve its melt processing fluidity while basically maintaining the impact resistance of the matrix, effectively overcoming the shortcomings of traditional flame-retardant systems that degrade the comprehensive mechanical properties of the composite material when improving flame retardancy.

[0007] The first aspect of the present invention provides a flame retardant composition comprising a dialkylphosphine hybrid salt and an acrylate compound; The dialkylphosphine hybrid salt is selected from at least one of compounds having the chemical formula shown in formula (I); Equation (Ⅰ), Among them, R1, R2, R3, R4, R5, and R6 are all independently selected from C1-C1. 12 Alkyl and / or C6-C 12 The aryl group; R1 and R2 are the first combination, R3 and R4 are the second combination, and R5 and R6 are the third combination, wherein the first combination, the second combination, and the third combination are different from each other; M is the central atom, selected from a metallic element, wherein the metallic element is selected from at least one of Group IIA, Group IIIA, Group IVA, Group VA, transition metals, and lanthanides; m is the valence state of metal M, and m is selected from 2, 3, or 4. 0≤x<1, 0≤y<1, 0≤z<1, at least two of x, y, and z are not 0, and x+y+z=1; The acrylate compound is selected from at least one of monomers containing acryloyloxy and / or methacryloyloxy functional groups and oligomers containing acryloyloxy and / or methacryloyloxy functional groups, wherein the number average molecular weight of the acrylate compound is not higher than 2000 g / mol. Based on the total weight of the flame retardant composition, the content of the acrylate compound is 0.5~7wt%.

[0008] Preferably, R1, R2, R3, R4, R5, and R6 in formula (Ⅰ) are all independently selected from C1-C 12 Alkyl and / or C6-C 12 aryl; C1-C 12 The alkyl group can be straight-chain or branched, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl, n-heptyl, isoheptyl, sec-heptyl, tert-heptyl, n-octyl, isooctyl, sec-octyl, tert-octyl, n-nonyl, sec-nonyl, tert-nonyl, n-decyl, isodel, sec-decyl, tert-decyl, n-undecyl, isoundecyl, sec-undecyl, tert-undecyl, n-dodecyl, isododecyl, sec-dodecyl, tert-dodecyl; C6-C 12 The aryl group refers to a substituted or unsubstituted aromatic hydrocarbon group, including but not limited to substituted or unsubstituted phenyl and substituted or unsubstituted naphthyl groups. R1, R2, R3, R4, R5, and R6 can be the same or different, and the first combination consisting of R1 and R2, the second combination consisting of R3 and R4, and the third combination consisting of R5 and R6 are all different from each other.

[0009] Optionally, R1, R2, R3, R4, R5, and R6 in formula (I) are each independently selected from C2-C8 alkyl groups; the C2-C8 alkyl groups can be straight-chain or branched alkyl groups, including but not limited to ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl, n-heptyl, isohexyl, sec-heptyl, tert-heptyl, n-octyl, isooctyl, sec-octyl, and tert-octyl. R1, R2, R3, R4, R5, and R6 can be the same or different, and the first combination formed by R1 and R2, the second combination formed by R3 and R4, and the third combination formed by R5 and R6 are all different from each other.

[0010] Optionally, R1, R2, R3, R4, R5, and R6 in formula (I) are each independently selected from one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. R1, R2, R3, R4, R5, and R6 may be the same or different, and the first combination formed by R1 and R2, the second combination formed by R3 and R4, and the third combination formed by R5 and R6 are all different from each other.

[0011] Optionally, the Group IIA metal element is selected from at least one of Be, Mg, Ca, Sr, and Ba; The Group IIIA metallic element is Al; The Group IVA metal element is Sn; The Group VA metal element is Sb; The transition metal element is selected from at least one of Fe, Zn, Cu, Ti, Zr, and Mn; The lanthanide metal element is Ce.

[0012] Preferably, the metallic element is selected from at least one of Al, Zn, Ca, and Fe.

[0013] Preferably, the metallic element is Al, and m=3.

[0014] In equation (Ⅰ), the values ​​of x, y, and z are the normalized values ​​of the concentrations of three corresponding dialkylphosphine ions, and x+y+z=1.

[0015] Optionally, the x, y, and z values ​​are independently selected from 0, 0.01, 0.02, 0.03, 0.05, 0.08, 0.10, 0.12, 0.15, 0.18, 0.20, 0.23, 0.25, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.38, 0.40, 0.42, 0.45, 0.48, 0.50, 0.52, 0.54, 0 The x+y+z = 1. The x-values ​​are any value from 0.55, 0.56, 0.58, 0.60, 0.62, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.80, 0.82, 0.85, 0.88, 0.90, 0.92, 0.95, 0.96, 0.97, 0.98, 0.99 or any value between any two of these.

[0016] Dialkylphosphine hybrid salts can be commercially available or prepared using conventional methods in the art. These methods include, but are not limited to, the following: reacting hypophosphite and / or its alkali metal salt with one or more corresponding olefins in the presence of a free radical initiator; reacting the resulting product with a metal source in an aqueous phase to prepare the dialkylphosphine hybrid salt. During the above preparation process, the addition reaction of hypophosphite and / or its alkali metal salt with the olefin in the presence of a free radical may produce long-chain alkyl-containing dialkylphosphite oligomers, which may also exist as impurities in compounds having formula (I). However, their amounts are small, and their chemical shifts are close to the corresponding dialkylphosphine ions. Therefore, during NMR phosphorus spectrum integration, they are incorporated into the corresponding dialkylphosphine ions. The dialkylphosphine hybrid salt also contains one or more other phosphorus-containing impurities, including phosphates, phosphites, alkylphosphinates, and alkylphosphinates, which are not included in x, y, and z. Based on the total molar amount of phosphorus, as long as the total molar amount of the other phosphorus-containing components (i.e., phosphorus-containing acid radicals other than the compound with the structure shown in formula (I)) does not exceed 10% of the total molar amount of phosphorus, the dialkylphosphine hybrid salt can still achieve the expected flame-retardant effect when used as a flame retardant.

[0017] Optionally, the dialkylphosphine hybrid salt may be at least one of diethyl-ethylpropylphosphine hybrid aluminum salt, diethyl-ethylpropyl-dipropylphosphine hybrid aluminum salt, diethyl-ethylbutyl-di-n-butylphosphine hybrid aluminum salt, and diethyl-ethylisobutyl-diisobutylphosphine hybrid aluminum salt.

[0018] The acrylate compounds are selected from those containing an acryloyloxy group (CH2=CH-COO). - ) and / or methacryloyloxy (CH2=C(CH3)-COO - At least one of the following: monomers with functional groups, oligomers containing acryloyloxy and / or methacryloyloxy functional groups.

[0019] The functional groups described in this application specification are "acryloyloxy and / or methacryloyloxy". One functional group is one acryloyloxy or one methacryloyloxy; two functional groups are "two acryloyloxy" or "two methacryloyloxy" or "one acryloyloxy and one methacryloyloxy"; three functional groups are "three acryloyloxy" or "three methacryloyloxy" or "one acryloyloxy and two methacryloyloxy" or "two acryloyloxy and one methacryloyloxy", and so on.

[0020] Preferably, the acrylate compound is a multifunctional monomer having at least two functional groups or a multifunctional oligomer having at least two functional groups, and its number average molecular weight is not higher than 2000 g / mol.

[0021] Optionally, the acrylate compound is at least one of a multifunctional acrylate monomer having at least two functional groups or a multifunctional methacrylate monomer having at least two functional groups.

[0022] Optionally, the acrylate compound is at least one of a multifunctional acrylate monomer having 2 to 4 functional groups or a multifunctional methacrylate monomer having 2 to 4 functional groups.

[0023] Optionally, the acrylate compound is selected from at least one of ethylene glycol dimethacrylate, hexanediol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, bisphenol A diacrylate ethoxylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, propoxyglycerol triacrylate, ethoxytrimethylolpropane trimethacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

[0024] Preferably, the acrylate compound is selected from at least one of ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

[0025] Preferably, the content of the acrylate compound is 0.5~7 wt% based on the total weight of the flame-retardant composition. This application has found that adding a small amount of acrylate compound to a dialkylphosphine hybrid salt having the chemical formula shown in formula (I) exhibits a significant synergistic effect. Applying this flame-retardant composition to glass fiber reinforced PBT effectively improves the flame-retardant and processing properties of the glass fiber reinforced PBT material while maintaining or slightly improving its impact resistance. Furthermore, the amount of acrylate compound added has a significant impact on the overall performance of the flame-retardant PBT material: when the amount is less than 0.5 wt% of the total weight of the flame-retardant composition, the flame-retardant efficiency promotion and drip suppression effects are not significant; while when the amount exceeds 7 wt% of the total weight of the flame-retardant composition, excessive addition not only negatively affects the flame-retardant performance but also adversely affects the impact resistance of the material. In addition, within a suitable range, the synergistic effect of the two can also increase the melt flow rate of PBT, which is beneficial for improving processing fluidity.

[0026] Based on the above findings, the content of the dialkylphosphine hybrid salt is 93-99.5 wt%, based on the total weight of the flame-retardant composition; optionally, the content of the dialkylphosphine hybrid salt in the flame-retardant composition is any value or a range between any two of 93 wt%, 93.5 wt%, 94 wt%, 94.5 wt%, 95 wt%, 95.5 wt%, 96 wt%, 96.5 wt%, 97 wt%, 97.5 wt%, 98 wt%, 98.5 wt%, 99 wt%, and 99.5 wt%. The content of the acrylate compound in the flame-retardant composition is 0.5-7 wt%; optionally, the content of the acrylate compound in the flame-retardant composition is any value or a range between any two of 0.5 wt%, 1 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, and 7 wt%.

[0027] Preferably, the flame retardant composition contains 95-99 wt% of a dialkylphosphine hybrid salt and 1-5 wt% of an acrylate compound.

[0028] Preferably, the flame retardant composition contains 97-98.5 wt% of a dialkylphosphine hybrid salt and 1.5-3 wt% of an acrylate compound.

[0029] Preferably, the flame retardant composition contains 97.9-98.3 wt% of a dialkylphosphine hybrid salt and 1.7-2.1 wt% of an acrylate compound.

[0030] Preferably, the flame retardant composition comprises a dialkylphosphine hybrid salt and an acrylate compound.

[0031] A second aspect of the present invention provides a thermoplastic flame-retardant polymer material, the thermoplastic flame-retardant polymer material comprising the flame-retardant composition and the thermoplastic polymer material, wherein the content of the flame-retardant composition in the thermoplastic flame-retardant polymer material is 5-30 wt%; The thermoplastic polymer material is selected from thermoplastic polyester.

[0032] The flame-retardant composition is present in the thermoplastic flame-retardant polymer material at a content of 8-26 wt%. The upper limit is selected from any value among 26 wt%, 25 wt%, 24 wt%, 23 wt%, 22 wt%, 21 wt%, 20 wt%, 19 wt%, 18 wt%, 17 wt%, 16 wt%, and 15 wt%, and the lower limit is selected from any value among 15 wt%, 14 wt%, 13 wt%, 12 wt%, 11 wt%, 10 wt%, 9 wt%, and 8 wt%.

[0033] A third aspect of the present invention provides a flame-retardant thermoplastic polyester composite material, comprising thermoplastic polyester, the flame-retardant composition, and glass fiber; the content of the flame-retardant composition is 8-26 wt% based on the total weight of the flame-retardant thermoplastic polyester composite material.

[0034] The lower limit of the amount of the flame-retardant composition is determined by the UL94 V-0 flame retardant rating threshold, while the upper limit is limited by its degrading effect on impact strength and flowability. The content of the flame-retardant composition in the flame-retardant thermoplastic polyester composite material is 8~26wt%. The upper limit is selected from any value among 26wt%, 25wt%, 24wt%, 23wt%, 22wt%, 21wt%, 20wt%, 19wt%, 18wt%, 17wt%, 16wt%, and 15wt%, and the lower limit is selected from any value among 15wt%, 14wt%, 13wt%, 12wt%, 11wt%, 10wt%, 9wt%, and 8wt%.

[0035] Optionally, the flame retardant composition is present in the flame retardant thermoplastic polyester composite material at a content of 10-22 wt%.

[0036] Optionally, the flame retardant composition is present in the flame retardant thermoplastic polyester composite material at a content of 12-20 wt%.

[0037] Optionally, the flame retardant composition is present in the flame retardant thermoplastic polyester composite material at a content of 14-18 wt%.

[0038] The dialkylphosphine hybrid salt and acrylate compounds in the flame retardant composition can be pre-mixed and added to the thermoplastic polyester, or they can be added to the thermoplastic polyester at different stages for processing.

[0039] The glass fiber is alkali-free glass fiber, and its length and diameter are not particularly limited. Optionally, the diameter of the glass fiber is 3~20μm and the length is 2~15mm; optionally, the glass fiber is treated with a silane coupling agent to improve the interfacial bonding force with the resin.

[0040] Optionally, based on the total weight of the flame-retardant thermoplastic polyester composite material, the glass fiber content is 10-40 wt%. The upper limit is selected from any value among 40 wt%, 39 wt%, 38 wt%, 37 wt%, 36 wt%, 35 wt%, 32 wt%, 30 wt%, 28 wt%, 26 wt%, 25 wt%, 24 wt%, 23 wt%, 22 wt%, 21 wt%, and 20 wt%, and the lower limit is selected from any value among 18 wt%, 17 wt%, 16 wt%, 15 wt%, 14 wt%, 13 wt%, 12 wt%, 11 wt%, and 10 wt%.

[0041] Optionally, to improve the processing properties, performance characteristics, or impart specific functions to the composition, the flame-retardant thermoplastic polyester composite material further comprises functional additives. These functional additives are selected from one or more of the following categories known in the art: antioxidants, anti-dripping agents, heat stabilizers, light stabilizers, UV absorbers, flame retardant synergists, nucleating agents, chain extenders, plasticizers, lubricants, release agents, antistatic agents, toughening agents, reinforcing agents, dispersants, charring catalysts, pigments, dyes, optical brighteners, and inorganic fillers.

[0042] Optionally, the antioxidant is selected from a compound of hindered phenols and phosphites.

[0043] Optionally, the content of the functional additive in the flame-retardant thermoplastic polyester composite material is 0~10wt%. Examples include any value or a range between any two values ​​from 0wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.7wt%, 0.9wt%, 1.0wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, to 10wt%.

[0044] Optionally, the thermoplastic polyester is selected from one or more of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene terephthalate (PTT), and poly(1,4-cyclohexanedimethyl terephthalate) (PCT).

[0045] Preferably, the thermoplastic polyester is polybutylene terephthalate.

[0046] More preferably, the polybutylene terephthalate is engineering plastic grade polybutylene terephthalate, which is a homopolymer or copolymer.

[0047] Optionally, based on the total weight of the flame-retardant thermoplastic polyester composite material, the content of the thermoplastic polyester is 25~72wt%, which can be any one value or a range between any two values ​​from 25wt%, 28wt%, 30wt%, 32wt%, 35wt%, 37wt%, 40wt%, 42wt%, 45wt%, 48wt%, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 72wt%.

[0048] Preferably, based on the total weight of the flame-retardant thermoplastic polyester composite material, the content of the flame-retardant composition is 8-26 wt%, the content of glass fiber is 20-40 wt%, the content of functional additives is 0-10 wt%, and the balance is thermoplastic polyester.

[0049] In traditional technologies, acrylate toughening agents must exist in polymer form to dissipate impact energy through shear yielding and creasing effects induced by their elastomeric phase within the matrix. However, small-molecule acrylate compounds, due to their limited molecular chain length, cannot construct an effective stress transfer network. Conventionally, they not only lack this toughening function but are also prone to deteriorating the original mechanical properties of the matrix due to plasticization or interface defects. However, this application unexpectedly discovered that by adding only a significantly lower amount of small-molecule acrylate compounds than traditional acrylate toughening agents, and combining them with dialkylphosphine hybrid salts applied to a thermoplastic polyester matrix, the resulting flame-retardant material maintains high flame-retardant efficiency while completely restoring its impact strength to, and even slightly exceeding, that of the pure thermoplastic polyester matrix. Crucially, the impact resistance of this compound system is significantly better than the control system containing only the hybrid salt. This comparative result indicates that small-molecule acrylates are not inert fillers and have an unexpected compensatory effect on the toughness reduction caused by the hybrid salt. It is worth noting that the aforementioned impact resistance compensation effect does not come at the expense of processability; on the contrary, the combination of this small molecule acrylate with hybrid salt can significantly improve the melt flow rate (MFR) of the material, demonstrating a comprehensive advantage of flame retardancy, impact resistance and processability.

[0050] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a novel flame retardant composition comprising a dialkylphosphine hybrid salt having the formula (I) and a small molecule acrylate compound in a specific ratio. Through the synergistic flame retardant effect of the two, the flame retardant efficiency of the hybrid salt on thermoplastic polyester is effectively improved, overcoming the problems of large addition amount and low flame retardant efficiency of existing flame retardant systems for thermoplastic polyester.

[0051] 2. This application adds an appropriate amount of flame retardant composition to thermoplastic polyester materials, which increases the melt flow rate (MFR) without sacrificing impact strength, thus breaking through the technical barrier that improving impact resistance inevitably sacrifices processing fluidity in traditional technology.

[0052] 3. This application overcomes the technical obstacle of achieving both flame retardancy and impact resistance simultaneously. By introducing small molecule acrylate compounds into the dialkylphosphine hybrid salt, the material maintains good impact strength while achieving a V-0 flame retardancy rating.

[0053] 4. The flame retardant composition of the present invention has simple components and can achieve the V-0 flame retardant rating without the need for additional flame retardant synergists. This avoids the problem of easy migration and precipitation of additives such as MPP added in traditional multi-component systems. The surface of the part is smooth and clean, and it can maintain stable appearance and mechanical properties for a long time. It can meet the strict requirements of thin-walled and precision parts for comprehensive performance. Detailed Implementation

[0054] In the description of this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, and includes both a and b. "Multiple" includes two or more types, and can be two, three, four, five, or more.

[0055] The technical solution of the present invention will be further described and illustrated below through specific embodiments. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the present invention. Furthermore, unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used in the art, and the methods used in the embodiments are all conventional methods in the art.

[0056] The raw materials used in the following examples and comparative examples are as follows: PBT (30%GF): Polybutylene terephthalate, glass fiber content 30wt%, Crastin SK605NC010, formerly DuPont brand; Dialkylphosphine hybrid salt 1: Diethyl / ethylpropyl / dipropylphosphine hybrid aluminum salt, wherein R1, R2, and R3 in formula (Ⅰ) are ethyl, R4, R5, and R6 are propyl, M is aluminum, m=3, x=0.29, y=0.63, and z=0.08, prepared according to patent application 202210412718.6; Dialkylphosphine hybrid salt 2: Diethyl / ethylpropyl / dipropylphosphine hybrid aluminum salt, wherein R1, R2, and R3 in formula (I) are ethyl, R4, R5, and R6 are propyl, M is aluminum, m=3, x=0.49, y=0.48, and z=0.03, prepared according to patent application 202210412718.6; Dialkylphosphine hybrid salt 3: Diethyl / ethylpropylphosphine hybrid aluminum salt, wherein R1, R2, and R3 in formula (I) are ethyl, R4 is propyl, M is aluminum, m=3, x=0.83, y=0.17, z=0, prepared according to patent application 202210412718.6; Dialkylphosphine hybrid salt 4: diethyl / ethyl isobutyl / diisobutylphosphine hybrid aluminum salt, wherein R1, R2, and R3 in formula (I) are ethyl, R4, R5, and R6 are isobutyl, M is aluminum, m=3, x=0.62, y=0.31, and z=0.07, prepared according to patent application 202111205673.7; Acrylate compound 1: Ethylene glycol dimethacrylate, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; Acrylate compound 2: Trimethylolpropane trimethacrylate, purchased from Shanghai Mairui Biochemical Technology Co., Ltd.; Acrylate compound 3: Pentaerythritol tetraacrylate, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; AlPi: Aluminum diethylphosphinic acid, Exolit OP 1230, Clariant GmbH, Germany; Antioxidant 1010: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Shanghai Maclean Biochemical Technology Co., Ltd. Antioxidant 168: Tris[2,4-di-tert-butylphenyl]phosphite, Strem, Inc., USA; Compound antioxidants: Antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) and antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite) are mixed in a 1:1 weight ratio.

[0057] The testing standards involved in the following examples and comparative examples are as follows: Combustion test standard: GB / T 2408-2008, test sample thickness is 1.6mm.

[0058] Notched impact strength test standard: GB / T 1843-2008, the nominal energy of the test is 1J.

[0059] Melt flow rate (MFR): Tested according to GB / T 3682-2018 under the conditions of a load of 2.16 kg and a temperature of 235℃.

[0060] Example 1 PBT (30%GF), dialkylphosphine hybrid salt 1, and acrylate compound 1 were added to a mixer at 50 rpm according to the weight percentages in Table 1. The mixer was set to 260℃ and mixed for 5 minutes. After mixing, the mixture was removed, cooled, and dried. The sample was then filled into a mold and preheated in a flat vulcanizing press at 260℃. Once the mold was completely filled, pressure was applied to 10 MPa and held for 5 minutes. After holding, the sample was removed and cold-pressed at room temperature while maintaining the pressure. After the sample cooled to room temperature, it was cut and tested. The results are shown in Table 1.

[0061] Example 2-12 In Examples 2-12, the raw materials and their weight percentages are shown in Table 1. Samples were prepared and tested in the manner of Example 1, and the results are shown in Tables 1 and 3.

[0062] Comparative Examples 1-14 In Comparative Examples 1-14, the raw materials and their weight percentages are shown in Table 2. Samples were prepared and tested in the manner of Example 1, and the results are shown in Tables 2 and 3.

[0063] Table 1

[0064] Table 2

[0065] *NR indicates no rating for flame retardancy testing.

[0066] Table 3

[0067] The comparison of Examples 2, 2, and 14 shows that neither adding equal amounts of dialkylphosphine hybrid salts nor adding equal amounts of acrylate compounds alone can achieve a V-0 flame retardant rating. However, the combination of equal amounts of dialkylphosphine hybrid salts and acrylate compounds achieves a V-0 flame retardant effect. These results indicate that dialkylphosphine hybrid salts and acrylate compounds have a synergistic flame retardant effect. The results of Examples 1-12 show that dialkylphosphine hybrid salts with different R1, R2, R3, R4, R5, and R6 substituents and acrylate compounds with different numbers of acrylate groups all exhibit a synergistic flame retardant effect. Furthermore, the introduction of antioxidants has no significant impact on this synergistic effect.

[0068] The comparative results of Examples 1-6 and Comparative Examples 4-5 show that the content of acrylate compounds in the flame retardant composition needs to be controlled within a specific range in order to exhibit a good synergistic effect with the dialkylphosphine hybrid salt and achieve a balance between flame retardant performance and impact resistance.

[0069] The results of Comparative Examples 10-12 show that replacing the dialkylphosphine hybrid salt of this application with aluminum diethylphosphine eliminates the synergistic flame retardant effect, and the impact resistance is not significantly improved. It is speculated that this is because the hybrid structure weakens the coordination between aluminum ions and anions. Although this results in lower thermal stability of the hybrid salt compared to aluminum diethylphosphine, it precisely matches its thermal decomposition temperature range with that of acrylate compounds, thus forming an effective synergistic flame retardant effect during heating. This indicates that the synergistic effect with acrylate compounds is selectively dependent on the structure of the dialkylphosphine salt, and not all dialkylphosphine salts can achieve this. The dialkylphosphine hybrid salt of formula (I) of this application exhibits a synergistic effect with acrylate compounds only within a certain proportion range.

[0070] Table 3 shows that when only the dialkylphosphine hybrid salt from this application is added (Comparative Example 1), the notched impact strength of the flame-retardant PBT material decreases. However, after further addition of acrylate compounds (Examples 2, 7, and 8), the resulting flame-retardant PBT materials achieve high flame-retardant efficiency while significantly improving the notched impact strength, even surpassing the level of pure PBT matrix. Comparative Examples 4 and 5 indicate that when the content of acrylate compounds in the flame-retardant composition is too low or too high, the flame-retardant effect and notched impact strength cannot meet expectations, indicating that there is a suitable window range for their dosage. Furthermore, data from MFR show that the introduction of the flame-retardant composition also imparts good processing fluidity to the flame-retardant PBT material.

[0071] In summary, this application demonstrates that by introducing only an appropriate amount of acrylate compounds into the dialkylphosphine hybrid salt, a significant synergistic flame-retardant effect can be achieved with the dialkylphosphine hybrid salt. Furthermore, in glass fiber reinforced PBT applications, the flame-retardant PBT material can simultaneously achieve high-efficiency flame retardancy, good impact resistance, and processing fluidity.

[0072] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0073] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0074] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A flame-retardant composition, characterized in that, The flame retardant composition comprises a dialkylphosphine hybrid salt and an acrylate compound; The dialkylphosphine hybrid salt is selected from at least one of compounds having the chemical formula shown in formula (I); Equation (Ⅰ), Among them, R1, R2, R3, R4, R5, and R6 are all independently selected from C1-C1. 12 Alkyl and / or C6-C 12 The aryl group; R1 and R2 are the first combination, R3 and R4 are the second combination, and R5 and R6 are the third combination, wherein the first combination, the second combination, and the third combination are different from each other; M is the central atom, selected from a metallic element, wherein the metallic element is selected from at least one of Group IIA, Group IIIA, Group IVA, Group VA, transition metals, and lanthanides; m is the valence state of metal M, and m is selected from 2, 3, or 4. 0≤x<1, 0≤y<1, 0≤z<1, at least two of x, y, and z are not 0, and x+y+z=1; The acrylate compound is selected from at least one of monomers containing acryloyloxy and / or methacryloyloxy functional groups and oligomers containing acryloyloxy and / or methacryloyloxy functional groups, wherein the number average molecular weight of the acrylate compound is not higher than 2000 g / mol. Based on the total weight of the flame retardant composition, the content of the acrylate compound is 0.5~7wt%.

2. The flame-retardant composition according to claim 1, characterized in that, In formula (Ⅰ), R1, R2, R3, R4, R5, and R6 are all independently selected from C2-C8 alkyl groups; the C2-C8 alkyl groups are straight-chain or branched alkyl groups, including ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl, n-heptyl, isoheptyl, sec-heptyl, tert-heptyl, n-octyl, isooctyl, sec-octyl, and tert-octyl. Alternatively, R1, R2, R3, R4, R5, and R6 in formula (Ⅰ) are each independently selected from one of ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. Alternatively, the Group IIA metal element is selected from at least one of Be, Mg, Ca, Sr, and Ba; the Group IIIA metal element is Al; the Group IVA metal element is Sn; the Group VA metal element is Sb; the transition metal element is selected from at least one of Fe, Zn, Cu, Ti, Zr, and Mn; and the lanthanide metal element is Ce.

3. The flame-retardant composition according to claim 1, characterized in that, The metallic element is selected from at least one of Al, Zn, Ca, and Fe; Alternatively, the metallic element is Al, and m=3.

4. The flame-retardant composition according to claim 1, characterized in that, The dialkylphosphine hybrid salt is at least one of diethyl-ethylpropylphosphine hybrid aluminum salt, diethyl-ethylpropyl-dipropylphosphine hybrid aluminum salt, diethyl-ethylbutyl-di-n-butylphosphine hybrid aluminum salt, and diethyl-ethylisobutyl-diisobutylphosphine hybrid aluminum salt. Alternatively, the acrylate compound is a multifunctional monomer having at least two functional groups or a multifunctional oligomer having at least two functional groups, and its number average molecular weight is not higher than 2000 g / mol.

5. The flame-retardant composition according to claim 1, characterized in that, The acrylate compound is at least one of a multifunctional acrylate monomer having 2 to 4 functional groups or a multifunctional methacrylate monomer having 2 to 4 functional groups.

6. The flame-retardant composition according to claim 1, characterized in that, The acrylate compound is selected from at least one of ethylene glycol dimethacrylate, hexanediol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, bisphenol A diacrylate ethoxylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, glyceryl propoxylate, trimethylolpropane trimethacrylate ethoxylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

7. A thermoplastic flame-retardant polymer material, characterized in that, The thermoplastic flame-retardant polymer material comprises the flame-retardant composition as described in any one of claims 1-6 and the thermoplastic polymer material, wherein the content of the flame-retardant composition in the thermoplastic flame-retardant polymer material is 5-30 wt%. The thermoplastic polymer material is selected from thermoplastic polyester.

8. A flame-retardant thermoplastic polyester composite material, characterized in that, The flame-retardant thermoplastic polyester composite material comprises thermoplastic polyester, the flame-retardant composition as described in any one of claims 1-6, and glass fiber; based on the total weight of the flame-retardant thermoplastic polyester composite material, the content of the flame-retardant composition is 8-26 wt%.

9. The flame-retardant thermoplastic polyester composite material according to claim 8, characterized in that, The thermoplastic polyester is selected from one or more of polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, and poly(1,4-cyclohexanediol) terephthalate. Alternatively, the thermoplastic polyester is selected from polybutylene terephthalate; Alternatively, the flame-retardant thermoplastic polyester composite material may further include functional additives selected from one or more of the following: antioxidants, anti-dripping agents, heat stabilizers, light stabilizers, ultraviolet absorbers, flame retardant synergists, nucleating agents, chain extenders, plasticizers, lubricants, release agents, antistatic agents, toughening agents, reinforcing agents, dispersants, charring catalysts, pigments, dyes, optical brighteners, and inorganic fillers.

10. The flame-retardant thermoplastic polyester composite material according to claim 8, characterized in that, Based on the total weight of the flame-retardant thermoplastic polyester composite material, the flame-retardant composition contains 8-26 wt%, the glass fiber contains 20-40 wt%, the functional additives contain 0-10 wt%, and the balance is thermoplastic polyester.

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