A DOPO-HQ-based flame retardant, a preparation method and application thereof, and a flame-retardant and anti-dripping PET composite material and a preparation thereof

Abstract

The application provides a DOPO-HQ-based flame retardant, a preparation method and application thereof, and a flame-retardant anti-dripping PET composite material and preparation thereof, and belongs to the technical field of flame retardants. The DOPO-HQ-based flame retardant contains the DOPO structure of the efficient phosphorus-based flame retardant, and can impart the composite material with efficient flame-retardant self-extinguishing performance; in addition, the DOPO-HQ-based flame retardant contains the triazine structure, has high thermal stability and excellent high-temperature carbonization capacity, so that a large amount of carbon layer is generated in the composite material during the combustion process and covers the surface of the base material, thereby achieving the effects of anti-dripping and smoke suppression. The flame-retardant PET composite material prepared by using the DOPO-HQ-based flame retardant has similar thermal performance to pure PET, has the characteristics of high flame-retardant efficiency, halogen-free, no dripping and low smoke release amount under the condition of a small amount of addition (2-8 wt%) (at present, the addition amount of commercially available flame-retardant anti-dripping is greater than or equal to 15 wt%).

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flame retardant technology, and particularly relates to a DOPO-HQ-based flame retardant, a preparation method and application thereof, and a flame-retardant and anti-dripping PET composite material and preparation thereof. BACKGROUND

[0002] Island-in-the-sea fiber is a kind of composite fiber developed in the early 1970s, which has the characteristics of high added value and high performance. Polyethylene terephthalate (PET) is a common island component in island-in-the-sea fiber, and the island-in-the-sea fiber developed by PET has many excellent properties, such as smoothness, good adsorption performance, soft and elegant luster, etc. PET has good heat resistance, chemical stability, mechanical properties and excellent spinnability, and is widely used in film, packaging material and textile decoration material fields. However, PET is extremely flammable, with a limiting oxygen index of only 21%, and belongs to flammable materials. During the combustion process, a large amount of flaming drips will be generated, which not only causes burn and scald hazards to people, but also makes the flame spread rapidly and even causes secondary fire. However, the current mainstream commercial flame retardant is mainly single phosphorus-based. Phosphorus-based flame retardants mainly achieve flame-retardant effect by promoting the melting and dripping of PET during the combustion process. Anti-dripping agents often do not have flame-retardant properties, and a large amount of anti-dripping agents need to be added to give PET real anti-dripping performance, which makes the compatibility of PET composite material poor. Therefore, how to simultaneously achieve the flame-retardant modification and anti-dripping modification of PET has gradually become the research hotspot and main research direction of the majority of experts and scholars.

[0003] 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) is a commercial phosphorus-based flame retardant with high flame retardant efficiency. Currently, scholars at home and abroad use flame retardant DOPO-HQ to modify the flame retardance of various polymers such as fiber-reinforced polybutylene terephthalate (LGF / PBT) and epoxy resin. Sun et al. (Sun J, Zhang D, Shang X, et al. Flame-retardant properties and mechanism of LGF / PBT / DOPO-HQ-conjugated flame-retardant composites [J]. Frontiers in Chemistry, 2022, 10:981579.) used DOPO-HQ to modify LGF / PBT. When the content of DOPO-HQ reached 14wt%, the LGF / PBT / DOPO-HQ composite material reached UL 94 V-0 level (no melt dripping), and the LOI value increased from 21.2 to 26.4%. Wang et al. (Wang W, Cao Z, Wang Z. Investigation on the flame retardancy, thermal and mechanical properties of epoxy resin / cyanate ester composites based on mSiO2@ZrPB and DOPO-HQ [J]. Polymers for Advanced Technologies, 2023, 34(5): 1540-1556.) mixed mesoporous silica and N,N'-piperazine(zirconium dimethylene phosphonate) (mSiO2@ZrPB) with DOPO-HQ in a certain proportion and used it to cure the epoxy resin / cyanate ester (EPCE) copolymer. The study found that the EPCE composite containing 8.0wt% DOPO-HQ and 2.0wt% mSiO2@Zr PB reached UL-94 V-0, and the limiting oxygen index was as high as 30.5%.

[0004] However, the existing PET material still has the problems of poor melt dripping resistance and large amount of smoke release, and there is little research on the flame retardant performance when it is used as the island component of the island-in-sea fiber. Therefore, based on the research status of DOPO-HQ-based flame retardant and PET, it is of great significance to carry out innovative design of DOPO-HQ-based flame retardant, improve the flame retardant performance of PET composite material, and realize the high-quality preparation of island-in-sea fiber. It is urgent to solve. SUMMARY

[0005] The application aims to provide a DOPO-HQ-based flame retardant, a preparation method and application thereof, and a flame-retardant anti-dripping PET composite material and a preparation thereof, solve the problems of poor anti-dripping property and large smoke release amount of the existing PET material, realize the flame-retardant anti-dripping of the PET, and improve the flame-retardant property when the PET is used as an island component of an island fiber.

[0006] In order to achieve the above-mentioned application purposes, the application provides the following technical solutions.

[0007] The application provides a DOPO-HQ-based flame retardant having the structure shown in Formula 1.

[0008]

[0009] In Formula I, 5<=n<=10.

[0010] R includes

[0011] The application provides a preparation method of the DOPO-HQ-based flame retardant.

[0012] In a protective atmosphere, cyanuric chloride, an aromatic compound, a first catalyst and a first organic solvent are mixed to perform a nucleophilic substitution reaction, and an intermediate product is obtained.

[0013] The intermediate product, DOPO-HQ, a second catalyst and a second organic solvent are mixed to perform a condensation reaction, and the DOPO-HQ-based flame retardant is obtained.

[0014] The aromatic compound includes p-methylphenol, biphenyl alcohol, 3-styryl phenol, 2-hydroxy benzimidazole or p-hydroxybenzonitrile.

[0015] Preferably, the first catalyst includes pyridine, triethylamine, sodium acetate or anhydrous potassium carbonate; and the mass ratio of the cyanuric chloride, the aromatic compound and the first catalyst is 1-2.5:0.8-2.5:1.

[0016] Preferably, the first organic solvent includes ethanol, dichloromethane, chloroform or acetone; the temperature of the nucleophilic substitution reaction is 40-60 DEG C, and the time is 2-4 h.

[0017] Preferably, the second catalyst includes pyridine, triethylamine, sodium acetate or N,N-diisopropyl ethylamine; the mass ratio of the intermediate product and DOPO-HQ is 1:1-1.8; and the mass ratio of the intermediate product and the second catalyst is 1:0.5-1.4.

[0018] Preferably, the second organic solvent comprises dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide or acetone; the temperature of the condensation reaction is 80-120 DEG C, and the time is 10-12 hours.

[0019] The application provides application of the DOPO-HQ-based flame retardant or the DOPO-HQ-based flame retardant prepared by the preparation method in preparation of a flame-retardant and anti-dripping PET composite material.

[0020] The application provides a flame-retardant and anti-dripping PET composite material, which comprises the following raw materials in parts by mass: 100 parts of PET and 2-8 parts of a DOPO-HQ-based flame retardant.

[0021] The DOPO-HQ-based flame retardant is the DOPO-HQ-based flame retardant or the DOPO-HQ-based flame retardant prepared by the preparation method.

[0022] The application provides a preparation method of the flame-retardant and anti-dripping PET composite material, which comprises the following steps:

[0023] The PET and the DOPO-HQ-based flame retardant are mixed, and granulation is performed in a double-screw extruder to obtain a DOPO-HQ-based flame-retardant PET composite material.

[0024] Preferably, the temperature of the extruder is set as follows: the temperature of a first zone is 255-265 DEG C; the temperature of a second zone is 255-265 DEG C; the temperature of a third zone is 265-275 DEG C; the temperature of a fourth zone is 265-275 DEG C; and the temperature of a fifth zone is 265-275 DEG C.

[0025] The application provides a DOPO-HQ-based flame retardant, which contains a high-efficiency phosphorus-based flame retardant DOPO structure, can impart high-efficiency flame-retardant and self-extinguishing properties to a composite material, and further contains a triazine structure, has high thermal stability and excellent high-temperature carbonization capacity, and enables the composite material to generate a large amount of carbon layers and cover the surface of a substrate in a combustion process, so that the anti-dripping and smoke suppression effects are achieved.

[0026] The flame-retardant PET composite material prepared by using the DOPO-HQ-based flame retardant has similar thermal properties to pure PET, has the characteristics of high flame-retardant efficiency, halogen-free, no dripping and low smoke release in the case of a small amount of addition (2-8 wt%) (at present, the addition amount of a commercially available flame-retardant and anti-dripping agent is greater than or equal to 15 wt%). BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a synthesis route map of the DOPO-HQ-based flame retardant I in Examples 1 and 2;

[0028] Figure 2Synthesis route chart of the DOPO-HQ-based flame retardant II in Examples 3-4;

[0029] Figure 3 Synthesis route chart of the DOPO-HQ-based flame retardant III in Examples 5-6;

[0030] Figure 4 Synthesis route chart of the DOPO-HQ-based flame retardant IV in Examples 7-8;

[0031] Figure 5 Synthesis route chart of the DOPO-HQ-based flame retardant V in Examples 9-10;

[0032] Figure 6 Infrared spectrum of the flame retardant V prepared in Example 9. DETAILED DESCRIPTION

[0033] In the present application, if no special description, the required raw materials or reagents are all commercially available goods which are well known to those skilled in the art.

[0034] The present application provides a DOPO-HQ-based flame retardant, which has the structure as shown in Formula 1:

[0035]

[0036] In Formula I, 5≤n≤10;

[0037] R includes

[0038] The DOPO-HQ-based flame retardant according to the present application preferably has the structure as shown in Formula 2:

[0039]

[0040] The present application provides a preparation method of the DOPO-HQ-based flame retardant according to the above technical solution, which comprises the following steps:

[0041] In a protective atmosphere, cyanuric chloride, an aromatic compound, a first catalyst and a first organic solvent are mixed to perform a nucleophilic substitution reaction, so as to obtain an intermediate product;

[0042] The intermediate product, DOPO-HQ, a second catalyst and a second organic solvent are mixed to perform a condensation reaction, so as to obtain the DOPO-HQ-based flame retardant;

[0043] The aromatic compound includes p-methylphenol, diphenylolpropane, 3-styrylphenol, 2-hydroxybenzimidazole or p-hydroxybenzonitrile.

[0044] The present application mixes cyanuric chloride, aromatic compound, first catalyst and first organic solvent in a protective atmosphere to perform nucleophilic substitution reaction to obtain intermediate product.

[0045] In the present application, the protective atmosphere preferably comprises nitrogen;

[0046] The first catalyst preferably comprises pyridine, triethylamine, sodium acetate or anhydrous potassium carbonate; the mass ratio of cyanuric chloride, aromatic compound and first catalyst is preferably 1-2.5:0.8-2.5:1.

[0047] In the present application, the first organic solvent comprises ethanol, dichloromethane, chloroform or acetone; the present application does not have special limitation on the amount of the first organic solvent, which can be adjusted according to actual demand to ensure smooth reaction.

[0048] The present application preferably mixes cyanuric chloride and aromatic compound, stirs to fully dissolve the reactants in the first organic solvent, then adds the first catalyst, and performs reaction under stirring. The present application does not have special limitation on the stirring, which can be stirred according to the process well known in the art.

[0049] In the present application, the temperature of the nucleophilic substitution reaction is preferably 40-60℃, more preferably 50℃, and the time is preferably 2-4h, more preferably 3h.

[0050] After the nucleophilic substitution reaction is completed, the present application preferably filters and washes the obtained product in sequence, dries the obtained solid at 60-80℃ for 6-8h to obtain intermediate product; the washing preferably uses deionized water and tetrahydrofuran for 3-6 times in sequence. The present application does not have special limitation on the filtering, which can be performed according to the process well known in the art.

[0051] After obtaining the intermediate product, the present application mixes the intermediate product, DOPO-HQ, second catalyst and second organic solvent to perform condensation reaction to obtain DOPO-HQ-based flame retardant.

[0052] In the present application, the CAS number of DOPO-HQ (10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phospha-phenanthrene-10-oxide) is 99208-50-1, which is commercially available.

[0053] In the present application, the second catalyst preferably comprises pyridine, triethylamine, sodium acetate or N,N-diisopropyl ethylamine (DIEA); the mass ratio of the intermediate product and DOPO-HQ is preferably 1:1-1.8, more preferably 1:1.2-1.3; the mass ratio of the intermediate product and second catalyst is preferably 1:0.5-1.4, more preferably 1:1.2-1.3.

[0054] In the present application, the second organic solvent preferably comprises dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide or acetone; the present application does not have special limitation on the amount of the second organic solvent, which can be adjusted according to actual needs to ensure the smooth progress of the reaction.

[0055] Preferably, the intermediate product, DOPO-HQ and the second catalyst are added to the organic solvent to perform the condensation reaction under a protective atmosphere; the protective atmosphere preferably comprises nitrogen.

[0056] In the present application, the condensation reaction is preferably performed at a temperature of 80-120℃, more preferably 90-100℃, for 10-12h.

[0057] After the condensation reaction is completed, the product is preferably filtered and washed successively, and the obtained solid is dried at 60-80℃ for 6-8h to obtain the DOPO-HQ-based flame retardant; the washing is preferably performed with deionized water and acetone successively for 3-6 times.

[0058] The present application provides the application of the DOPO-HQ-based flame retardant in the preparation of the flame-retardant and anti-dripping PET composite material.

[0059] The present application provides a flame-retardant and anti-dripping PET composite material, which comprises the following raw materials in parts by mass: 100 parts of PET, 2-8 parts of DOPO-HQ-based flame retardant.

[0060] The DOPO-HQ-based flame retardant is the DOPO-HQ-based flame retardant described in the above technical solution or the DOPO-HQ-based flame retardant prepared by the preparation method described in the above technical solution.

[0061] The present application does not have special limitation on the specification of the PET, and the commercially available products in the art can be used.

[0062] In the present application, the amount of the DOPO-HQ-based flame retardant is preferably 3-6 parts, more preferably 4-5 parts.

[0063] The present application provides a preparation method of the flame-retardant and anti-dripping PET composite material described in the above technical solution, which comprises the following steps:

[0064] The PET and the DOPO-HQ-based flame retardant are mixed to perform granulation in a double-screw extruder to obtain the DOPO-HQ-based flame-retardant PET composite material.

[0065] In the present application, the temperature settings of the extruder are preferably: Zone 1 temperature: 255-265°C; Zone 2 temperature 255-265°C; Zone 3 temperature 265-275°C; Zone 4 temperature 265-275°C; Zone 5 temperature 265-275°C; the Zone 1 temperature is more preferably 260°C, the Zone 2 temperature is more preferably 260°C; the Zone 3 temperature is more preferably 270°C; the Zone 4 temperature is more preferably 270°C; the Zone 5 temperature is more preferably 270°C.

[0066] The technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0067] In the following examples, PET chips are purchased from Hualu Chemical Material Co., Ltd., CR-8863.

[0068] Example 1

[0069] The preparation of DOPO-HQ-based flame retardant I is as shown in Figure 1

[0070] Step 1: Under nitrogen protection, 37g of cyanuric chloride and 22g of p-methyl phenol were added to a three-necked round-bottom flask, the reactants were stirred to dissolve in ethanol, 16g of pyridine was added to the flask, the temperature was controlled at 60°C and stirred for 4h to obtain a reaction mixture;

[0071] Step 2: After the reaction of Step 1 was completed, the reaction mixture was filtered and washed with deionized water and tetrahydrofuran three times respectively, and the obtained solid was dried at 80°C for 6h to obtain an intermediate product;

[0072] Step 3: After Step 2 was completed, 52g of the intermediate product, 65g of DOPO-HQ, and 30g of triethylamine were added to a three-necked flask containing dimethyl sulfoxide under nitrogen protection, and a condensation reaction was carried out at a temperature of 80°C for 10h to obtain a reaction mixture;

[0073] Step 4: After the reaction of Step 3 was completed, the reaction mixture was filtered and washed with deionized water and acetone three times respectively, and the obtained solid was dried at 60°C for 6h to obtain a DOPO-HQ-based flame retardant (n=6);

[0074] Preparation of DOPO-HQ-based flame-retardant PET composite I-I:

[0075] According to the weight fraction, 100 parts of PET chips and 6 parts of the prepared DOPO-HQ-based flame retardant I were added to a twin-screw extruder, and the temperature settings were: Zone 1 temperature: 255°C; Zone 2 temperature 255°C; Zone 3 temperature 265°C; Zone 4 temperature 265°C; Zone 5 temperature 265°C, to obtain a DOPO-HQ-based flame-retardant PET composite I-I.

[0076] ​Performance test

[0077] The performance of the prepared PET composite I-I was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET (PET chip) (vertical combustion test NR, peak smoke release rate was 0.1113 m 2 / s, total smoke release amount was 17.7 m 2 ), the results showed that the prepared DOPO-HQ based flame retardant PET composite I-I was anti-dripping, and the vertical combustion test was V-0 level, the peak smoke release rate and the total smoke release amount were reduced by 30.1% and 23.2% respectively compared with the PET chip.

[0078] Example 2

[0079] The preparation of DOPO-HQ based flame retardant I is as shown in the following scheme: Figure 1

[0080] Step 1: Under nitrogen protection, 37 g of cyanuric chloride and 22 g of p-methyl phenol were added to a three-necked round-bottom flask, the reactants were stirred to dissolve in dichloromethane, then 20 g of triethylamine was added to the above flask, the temperature was controlled at 60°C, and the stirring was carried out for 4 h to obtain a reaction mixture;

[0081] Step 2: After the reaction of step 1 was completed, the reaction mixture was filtered, washed with deionized water and tetrahydrofuran for three times respectively, and the obtained solid was dried at 80°C for 6 h to obtain an intermediate product;

[0082] Step 3: After the reaction of step 2 was completed, 52 g of the intermediate product, 78 g of DOPO-HQ, and 31 g of DIEA were added to a three-necked flask containing dimethyl sulfoxide under nitrogen protection, and a condensation reaction was carried out at a temperature of 80°C for 12 h to obtain a reaction mixture;

[0083] Step 4: After the reaction of step 3 was completed, the reaction mixture was filtered, washed with deionized water and acetone for three times respectively, and the obtained solid was dried at 60°C for 6 h to obtain a DOPO-HQ based flame retardant (n=8);

[0084] Preparation of DOPO-HQ based flame retardant PET composite I-I:

[0085] According to the weight fraction, 100 parts of PET chip and 4 parts of prepared DOPO-HQ based flame retardant I were added to a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 255°C; zone 2 temperature: 255°C; zone 3 temperature: 265°C; zone 4 temperature: 265°C; zone 5 temperature: 265°C, to obtain a DOPO-HQ based flame retardant PET composite I-I.

[0086] Performance test

[0087] ​The performance of the prepared PET composite I-II was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ based flame retardant PET composite I-II was resistant to melt dripping, and the vertical combustion test was V-1 level, and the peak smoke release rate and total smoke release amount were reduced by 28.8% and 20.5% respectively compared with PET chips.

[0088] Example 3

[0089] The preparation of DOPO-HQ based flame retardant Ⅱ is as shown in Figure 2

[0090] Step 1: Under nitrogen protection, 37g of cyanuric chloride and 40g of biphenyl alcohol were added to a three-necked round-bottom flask, and the reactants were dissolved in ethanol by stirring. Then 16g of sodium acetate was added to the flask, and the temperature was controlled at 50°C for 3h of stirring to obtain a reaction mixture;

[0091] Step 2: After the reaction of step 1 was completed, the reaction mixture was filtered and washed with deionized water and tetrahydrofuran three times respectively. The obtained solid was dried at 60°C for 8h to obtain an intermediate product;

[0092] Step 3: After the reaction of step 2 was completed, 70g of the intermediate product, 78g of DOPO-HQ, and 70g of sodium acetate were added to a three-necked flask containing tetrahydrofuran under nitrogen protection. The condensation reaction was carried out at a temperature of 100°C for 12h to obtain a reaction mixture;

[0093] Step 4: After the reaction of step 3 was completed, the reaction mixture was filtered and washed with deionized water and acetone three times respectively. The obtained solid was dried at 60°C for 8h to obtain a DOPO-HQ based flame retardant (n=5);

[0094] Preparation of DOPO-HQ based flame retardant PET composite Ⅱ-I:

[0095] According to the weight fraction, 100 parts of PET chips and 6 parts of the prepared DOPO-HQ based flame retardant Ⅱ were added to a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 255°C; zone 2 temperature: 255°C; zone 3 temperature: 265°C; zone 4 temperature: 265°C; zone 5 temperature: 265°C, to obtain a DOPO-HQ based flame retardant PET composite Ⅱ-I.

[0096] Performance test

[0097] ​The performance of the prepared PET composite material is tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results show that the prepared DOPO-HQ-based flame retardant PET composite material II-I is anti-dripping, and the vertical combustion test is V-0 level, and the peak smoke release rate and total smoke release amount are reduced by 31.6% and 23.7% respectively compared with PET chips.

[0098] Example 4

[0099] The preparation of DOPO-HQ-based flame retardant Ⅱ is as shown in Figure 2

[0100] Step 1: Under the protection of nitrogen, 37g of cyanuric chloride and 40g of biphenyl alcohol are added to a three-necked round-bottom flask, and the reactants are stirred to dissolve in chloroform. Then 28g of anhydrous potassium carbonate is added to the above flask, and the temperature is controlled at 50°C for 3h of stirring to obtain a reaction mixture;

[0101] Step 2: After the reaction of step 1 is completed, filter, and then wash with deionized water and tetrahydrofuran for three times respectively. Dry the obtained solid at 60°C for 8h to obtain an intermediate product;

[0102] Step 3: After the end of step 2, under the protection of nitrogen, 70g of the intermediate product, 85g of DOPO-HQ, and 80g of pyridine are added to a three-necked flask containing tetrahydrofuran. The condensation reaction is carried out at a temperature of 120°C for 12h to obtain a reaction mixture;

[0103] Step 4: After the reaction of step 3 is completed, filter, and then wash with deionized water and acetone for three times respectively. Dry the obtained solid at 60°C for 8h to obtain a DOPO-HQ-based flame retardant (n=6);

[0104] Preparation of DOPO-HQ-based flame retardant PET composite material II-II:

[0105] According to the weight fraction, 100 parts of PET chips and 4 parts of the prepared DOPO-HQ-based flame retardant Ⅱ are added to a double-screw extruder, and the temperature is set as follows: the temperature of the first zone is 255°C; the temperature of the second zone is 255°C; the temperature of the third zone is 265°C; the temperature of the fourth zone is 265°C; and the temperature of the fifth zone is 265°C. Thus, a DOPO-HQ-based flame retardant PET composite material II-II is obtained.

[0106] Performance test

[0107] The performance of the prepared PET composite material is tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results show that the prepared DOPO-HQ-based flame retardant PET composite material II-I is anti-dripping, and the vertical combustion test is V-0 level, and the peak smoke release rate and total smoke release amount are reduced by 31.6% and 23.7% respectively compared with PET chips.​

[0108] Example 5

[0109] The preparation of DOPO-HQ-based flame retardant III is shown as follows: Figure 3

[0110] Step 1: Under nitrogen protection, 37 g of cyanuric chloride and 40 g of 3-phenylstyryl phenol were added into a three-necked round-bottom flask, the reactants were stirred to be dissolved in ethanol, then 20 g of triethylamine was added into the flask, the temperature was controlled at 40°C, and the stirring was performed for 4 h to obtain a reaction mixture;

[0111] Step 2: After the reaction of Step 1 was completed, the reaction mixture was filtered, washed with deionized water and tetrahydrofuran for three times respectively, and the obtained solid was dried at 60°C for 8 h to obtain an intermediate product;

[0112] Step 3: After the reaction of Step 2 was completed, 70 g of the intermediate product, 91 g of DOPO-HQ and 36 g of DIEA were added into a three-necked flask containing tetrahydrofuran, and a condensation reaction was performed at a temperature of 90°C for 10 h to obtain a reaction mixture;

[0113] Step 4: After the reaction of Step 3 was completed, the reaction mixture was filtered, washed with deionized water and acetone for three times respectively, and the obtained solid was dried at 60°C for 6 h to obtain a DOPO-HQ-based flame retardant (n=7);

[0114] Preparation of DOPO-HQ-based flame-retardant PET composite III-I:

[0115] According to the weight fraction, 100 parts of PET chips and 6 parts of the prepared DOPO-HQ-based flame retardant III were added into a twin-screw extruder, and the temperature was set as follows: the temperature of the first zone was 260°C; the temperature of the second zone was 260°C; the temperature of the third zone was 270°C; the temperature of the fourth zone was 270°C; and the temperature of the fifth zone was 270°C, to obtain a DOPO-HQ-based flame-retardant PET composite III-I.

[0116] Performance test

[0117] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite III-I was resistant to melt dripping, and the vertical combustion test was V-0 level, and the peak smoke release rate and total smoke release amount were reduced by 32.3% and 24.9% respectively compared with PET chips.

[0118] Example 6

[0119] The preparation of DOPO-HQ-based flame retardant III is shown as follows: Figure 3

[0120] ​​Step 1: under nitrogen protection, 37 g of cyanuric chloride and 40 g of 3-phenylstyryl phenol were added into a three-necked round-bottom flask, the reactants were stirred to dissolve in dichloromethane, then 16 g of sodium acetate was added into the flask, stirring was carried out at 40℃ for 4 h, and a reaction mixture was obtained;

[0121] Step 2: after the reaction in step 1 was completed, the reaction mixture was filtered, washed with deionized water and tetrahydrofuran for three times respectively, and the obtained solid was dried at 60℃ for 8 h, and an intermediate product was obtained;

[0122] Step 3: after the reaction in step 2 was completed, 70 g of the intermediate product, 72 g of DOPO-HQ and 50 g of pyridine were added into a three-necked round-bottom flask containing dimethyl sulfoxide, and a condensation reaction was carried out at 100℃ for 12 h, and a reaction mixture was obtained;

[0123] Step 4: after the reaction in step 3 was completed, the reaction mixture was filtered, washed with deionized water and acetone for three times respectively, and the obtained solid was dried at 80℃ for 6 h, and a DOPO-HQ-based flame retardant (n = 8) was obtained;

[0124] Preparation of DOPO-HQ-based flame-retardant PET composite Ⅲ-Ⅱ:

[0125] According to the weight fraction, 100 parts of PET chips and 8 parts of the prepared DOPO-HQ-based flame retardant Ⅲ were added into a twin-screw extruder, and the temperature was set as follows: the temperature of the first zone was 260℃, the temperature of the second zone was 260℃, the temperature of the third zone was 270℃, the temperature of the fourth zone was 270℃, and the temperature of the fifth zone was 270℃, and a DOPO-HQ-based flame-retardant PET composite Ⅲ-Ⅱ was obtained.

[0126] Performance test

[0127] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite Ⅲ-Ⅱ was resistant to melt dripping, and the vertical combustion test was V-0 level, and the peak smoke release rate and total smoke release amount were reduced by 33.6% and 25.7% respectively compared with PET chips.

[0128] Example 7

[0129] The preparation of DOPO-HQ-based flame retardant Ⅳ is as shown in Figure 4

[0130] Step 1: under nitrogen protection, 37 g of cyanuric chloride and 40 g of 3-phenylstyryl phenol were added into a three-necked round-bottom flask, the reactants were stirred to dissolve in dichloromethane, then 16 g of sodium acetate was added into the flask, stirring was carried out at 40℃ for 4 h, and a reaction mixture was obtained;

[0131] ​Step 2: After the reaction in step 1 is completed, filter, and then wash with deionized water and tetrahydrofuran three times, respectively. Dry the obtained solid at 80°C for 6h to obtain an intermediate product;

[0132] Step 3: After the reaction in step 2 is completed, add 56g of the intermediate product, 78g of DOPO-HQ, and 28g of pyridine to a three-necked flask containing N,N-dimethylformamide, and perform a condensation reaction at a temperature of 80°C for 10h to obtain a reaction mixture;

[0133] Step 4: After the reaction in step 3 is completed, filter, and then wash with deionized water and acetone three times, respectively. Dry the obtained solid at 60°C for 6h to obtain a DOPO-HQ-based flame retardant (n=9);

[0134] Preparation of DOPO-HQ-based flame-retardant PET composite IV-I:

[0135] According to weight parts, add 100 parts of PET chips and 6 parts of the prepared DOPO-HQ-based flame retardant IV to a twin-screw extruder, and set the temperature as follows: Zone 1 temperature: 260°C; Zone 2 temperature: 260°C; Zone 3 temperature: 270°C; Zone 4 temperature: 270°C; Zone 5 temperature: 270°C to obtain a DOPO-HQ-based flame-retardant PET composite IV-I.

[0136] Performance test

[0137] The performance of the prepared PET composite is tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results show that the prepared DOPO-HQ-based flame-retardant PET composite IV-I is resistant to melt dripping, and the vertical combustion test is V-0 level. The peak smoke release rate and total smoke release amount are reduced by 33.1% and 25.3% compared with PET chips, respectively.

[0138] Example 8

[0139] The preparation of DOPO-HQ-based flame retardant IV is as shown in Figure 4

[0140] Step 1: Under nitrogen protection, add 37g of cyanuric chloride and 27g of 2-hydroxybenzimidazole to a three-necked round-bottom flask, stir to dissolve the reactants in acetone, then add 20g of triethylamine to the flask, control the temperature at 60°C, and stir for 4h to obtain a reaction mixture;

[0141] Step 2: After the reaction in step 1 is completed, filter, and then wash with deionized water and tetrahydrofuran three times, respectively. Dry the obtained solid at 80°C for 6h to obtain an intermediate product;

[0142] ​Step 3: After step 2, 56 g of the intermediate product, 91 g of DOPO-HQ, and 30 g of sodium acetate were added to a three-necked flask containing N,N-dimethylformamide under nitrogen protection, and a condensation reaction was carried out at 80°C for 10 h to obtain a reaction mixture;

[0143] Step 4: After step 3, the reaction was filtered, and the obtained solid was washed with deionized water and acetone three times, respectively, and then dried at 60°C for 6 h to obtain a DOPO-HQ-based flame retardant;

[0144] Preparation of DOPO-HQ-based flame-retardant PET composite IV-I:

[0145] According to the weight fraction, 100 parts of PET chips and 4 parts of the prepared DOPO-HQ-based flame retardant IV were added to a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 260°C; zone 2 temperature: 260°C; zone 3 temperature: 270°C; zone 4 temperature: 270°C; zone 5 temperature: 270°C, to obtain a DOPO-HQ-based flame-retardant PET composite IV-I.

[0146] Performance test

[0147] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite IV-II was resistant to melt dripping, and the vertical combustion test was V-0 level, and the peak smoke release rate and total smoke release amount were reduced by 32.0% and 24.4% respectively compared with PET chips.

[0148] Example 9

[0149] The preparation of DOPO-HQ-based flame retardant V is as shown in Figure 5

[0150] Step 1: Under nitrogen protection, 37 g of cyanuric chloride and 24 g of p-hydroxybenzyl cyanide were added to a three-necked round-bottom flask, and the reactants were stirred to dissolve in chloroform. Then 28 g of anhydrous potassium carbonate was added to the flask, and the temperature was controlled at 50°C for stirring for 2 h to obtain a reaction mixture;

[0151] Step 2: After step 1, the reaction was filtered, and the obtained solid was washed with deionized water and tetrahydrofuran three times, respectively, and then dried at 60°C for 8 h to obtain an intermediate product;

[0152] Step 3: After step 2, 54 g of the intermediate product, 66 g of DOPO-HQ, and 28 g of triethylamine were added to a three-necked flask containing acetone under nitrogen protection, and a condensation reaction was carried out at 120°C for 10 h to obtain a reaction mixture;

[0153] ​Step 4: After the reaction of step 3 was completed, the product was filtered, washed with deionized water and acetone three times, respectively, and then dried at 80°C for 6h to obtain the DOPO-HQ-based flame retardant (n=6);

[0154] Preparation of DOPO-HQ-based flame-retardant PET composite V-I:

[0155] According to the weight fraction, 100 parts of PET chips and 4 parts of the prepared DOPO-HQ-based flame retardant V were added into a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 265°C; zone 2 temperature: 265°C; zone 3 temperature: 275°C; zone 4 temperature: 275°C; zone 5 temperature: 275°C, to obtain the DOPO-HQ-based flame-retardant PET composite V-I.

[0156] Performance test

[0157] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite V-I was resistant to melt dripping, and the vertical combustion test was V-0 level, and the peak smoke release rate and total smoke release amount were reduced by 33.3% and 25.8% compared with PET chips, respectively.

[0158] Figure 6 The infrared spectrum of the flame retardant V prepared in Example 9 is shown in Figure 6 , the absorption peaks of the flame retardant V at wave numbers 2231 cm -1 , 1500 cm -1 , and 943 cm -1 correspond to-CN, triazine ring and DOPO-HQ structure, respectively, confirming that the flame retardant V has been successfully prepared.

[0159] Example 10

[0160] The preparation of DOPO-HQ-based flame retardant V is shown in Figure 5 :

[0161] Step 1: Under nitrogen protection, 37g of cyanuric chloride and 24g of p-hydroxybenzonitrile were added into a three-necked round-bottom flask, and the reactants were stirred to dissolve in chloroform. Then 28g of anhydrous potassium carbonate was added into the flask, and the temperature was controlled at 60°C for stirring for 4h to obtain a reaction mixture;

[0162] Step 2: After the reaction of step 1 was completed, the product was filtered, washed with deionized water and tetrahydrofuran three times, respectively, and then dried at 60°C for 8h to obtain the intermediate product;

[0163] Step 3: After step 2, 55 g of the intermediate product, 65 g of DOPO-HQ, and 35 g of triethylamine were added to a three-necked flask containing acetone under nitrogen protection, and a condensation reaction was carried out at a temperature of 120°C for 10 h to obtain a reaction mixture;

[0164] Step 4: After the reaction in step 3 was completed, the product was filtered and washed with deionized water and acetone three times each, and the obtained solid was dried at 80°C for 6 h to obtain a DOPO-HQ-based flame retardant (n = 5);

[0165] Preparation of DOPO-HQ-based flame-retardant PET composite V-I:

[0166] According to the weight fraction, 100 parts of PET chips and 2 parts of the prepared DOPO-HQ-based flame retardant V were added to a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 265°C; zone 2 temperature: 265°C; zone 3 temperature: 275°C; zone 4 temperature: 275°C; and zone 5 temperature: 275°C, to obtain a DOPO-HQ-based flame-retardant PET composite V-II.

[0167] Performance test

[0168] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite V-II was resistant to melt dripping, and the vertical combustion test was V-0 level, and the peak smoke release rate and total smoke release amount were reduced by 32.2% and 25.0% respectively compared with PET chips.

[0169] Comparative example 1

[0170] Preparation of DOPO-HQ flame-retardant PET composite:

[0171] According to the weight fraction, 100 parts of PET chips and 8 parts of the flame retardant DOPO-HQ (Zhengzhou Yanded Biological Technology Co., Ltd.) were added to a twin-screw extruder, and the temperature was set as follows: zone 1 temperature: 255°C; zone 2 temperature: 255°C; zone 3 temperature: 255°C; zone 4 temperature: 255°C; and zone 5 temperature: 255°C, to obtain a DOPO-HQ and PET composite.

[0172] Performance test

[0173] The performance of the prepared PET composite was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the prepared DOPO-HQ-based flame-retardant PET composite had melt dripping phenomenon during combustion, and the vertical combustion test was V-1 level, and the peak smoke release rate and total smoke release amount were increased by 25.2% and 15.0% respectively compared with PET chips.

[0174] Comparative Example 2

[0175] Preparation of triazine-based flame-retardant PET composite material:

[0176] According to the weight fraction, 100 parts of PET chip, 15 parts of the intermediate product (triazine-based flame retardant) prepared in step 2 of Example 9 was added into a double screw extruder, and the temperature was set as follows: the temperature of the first zone was 260℃; the temperature of the second zone was 260℃; the temperature of the third zone was 270℃; the temperature of the fourth zone was 270℃; and the temperature of the fifth zone was 270℃, to obtain the triazine-based flame-retardant PET composite material.

[0177] Performance test

[0178] The performance of the prepared PET composite material was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the triazine-based flame-retardant PET composite material had melt dripping phenomenon during combustion process, the vertical combustion test was V-2 level, and the peak smoke release rate and total smoke release amount were reduced by 10.2% and 6.0% respectively compared with PET chip.

[0179] Comparative Example 3

[0180] Preparation of DOPO-HQ and triazine-based flame-retardant PET composite material:

[0181] According to the weight fraction, 100 parts of PET chip, 10 parts of DOPO-HQ, and 5 parts of the intermediate product (triazine-based flame retardant) prepared in step 2 of Example 9 were added into a double screw extruder, and the temperature was set as follows: the temperature of the first zone was 250℃; the temperature of the second zone was 250℃; the temperature of the third zone was 250℃; the temperature of the fourth zone was 250℃; and the temperature of the fifth zone was 250℃, to obtain the DOPO-HQ and triazine-based flame-retardant PET composite material.

[0182] Performance test

[0183] The performance of the prepared PET composite material was tested by vertical combustion test and limiting oxygen index method, and compared with pure PET. The results showed that the DOPO-HQ and triazine-based flame-retardant PET composite material had melt dripping phenomenon during combustion process, and the vertical combustion test was V-1 level, and the peak smoke release rate and total smoke release amount were reduced by 13.2% and 7.0% respectively compared with PET chip.

[0184] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A DOPO-HQ-based flame retardant, characterized in that: Having the structure described in formula I: In formula I, 5≤n≤10; R is selected from 2. The method for preparing the DOPO-HQ-based flame retardant according to claim 1, characterized in that: The following steps are involved: In a protective atmosphere, cyanuric chloride, an aromatic compound, a first catalyst and a first organic solvent are mixed to carry out a nucleophilic substitution reaction to obtain an intermediate product; mixing the intermediate product, DOPO-HQ, a second catalyst, and a second organic solvent to carry out a condensation reaction to obtain a DOPO-HQ-based flame retardant; The aromatic compound is selected from p-methylphenol, 2-biphenylmethanol, 3-phenylenediol, 2-hydroxybenzimidazole or p-hydroxybenzonitrile.

3. The preparation method according to claim 2, characterized in that The first catalyst is selected from pyridine, triethylamine, sodium acetate or anhydrous potassium carbonate; the mass ratio of the cyanuric chloride, aromatic compound and the first catalyst is 1-2.5:0.8-2.5:

1.

4. The preparation method according to claim 2 or 3, characterized in that The first organic solvent is selected from ethanol, dichloromethane, chloroform or acetone; the temperature of the nucleophilic substitution reaction is 40-60° C., and the time is 2-4 hours.

5. The preparation method according to claim 2, characterized in that The second catalyst is selected from pyridine, triethylamine, sodium acetate or N,N-diisopropylethylamine; the mass ratio of the intermediate product to DOPO-HQ is 1:1-1.8; the mass ratio of the intermediate product to the second catalyst is 1:0.5-1.

4.

6. The preparation method according to claim 2 or 5, characterized in that The second organic solvent is selected from dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide or acetone; the temperature of the condensation reaction is 80-120° C., and the time is 10-12 hours.

7. Use of the DOPO-HQ-based flame retardant according to claim 1 or the DOPO-HQ-based flame retardant prepared by the preparation method according to any one of claims 2 to 6 in the preparation of a flame-retardant and drip-resistant PET composite material.

8. A flame retardant and anti-drip PET composite material, characterized in that: The preparation method comprises the following raw materials in parts by weight: 100 parts of PET and 2 to 8 parts of DOPO-HQ-based flame retardant; The DOPO-HQ-based flame retardant is the DOPO-HQ-based flame retardant according to claim 1 or the DOPO-HQ-based flame retardant prepared by the preparation method according to any one of claims 2 to 6.

9. The method for preparing the flame-retardant and drip-resistant PET composite material according to claim 8, characterized in that: The following steps are involved: PET and a DOPO-HQ-based flame retardant are mixed and pelletized in a twin-screw extruder to obtain a DOPO-HQ-based flame retardant PET composite material.

10. The preparation method according to claim 9, characterized in that The temperature of the extruder is set as follows: zone 1 temperature: 255-265°C; zone 2 temperature: 255-265°C; zone 3 temperature: 265-275°C; zone 4 temperature: 265-275°C; zone 5 temperature: 265-275°C.

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