A perylene imide-dopo colored flame retardant and a preparation method and application thereof

Abstract

This invention provides a perylene diimide-DOPO colored flame retardant, its preparation method, and its application, relating to the field of polymer material additives. The general structural formula of this perylene diimide-DOPO colored flame retardant is: PDI–[N–CH2CH2–O–P(=O)(OR)(OR')]2, where PDI represents the perylene diimide chromophore skeleton, PDI–N– represents the nitrogen atom on the imide group in the perylene diimide molecule, –CH2-CH2–O– represents the ethylene ether bond, P(=O)(OR)(OR') represents the phosphate ester group; R and R' each independently represent two substituents on the phosphate ester group. This invention realizes a functional molecule that integrates flame retardancy and coloring, which is of great significance for improving the flame retardant properties and service stability of textile fibers and engineering plastics.

Description

Technical Field

[0001] This invention relates to the field of polymer material additives, and more specifically, to a perylene imide-DOPO colored flame retardant, its preparation method, and its application. Background Technology

[0002] In the field of polymer materials, flame retardants and colorants are key additives for achieving flame retardant properties and color effects. However, in the prior art, flame retardants and colorants are usually added as separate independent components. For example, the existing patent CN106459255B discloses a scheme of adding a phosphorus-containing flame retardant polymer to a plastic composition and adding conventional pigments or colorants. This method of adding "flame retardant + colorant" in parallel has some shortcomings: (1) adverse interactions may occur between different additives, affecting the thermal stability of the colorant or the efficiency of the flame retardant; (2) low molecular weight flame retardants are prone to migration and loss, resulting in poor long-term stability; (3) the addition of colorants may reduce the effective content of the flame retardant in the material, thereby weakening the flame retardant effect.

[0003] Currently, researchers have proposed several solutions to address the aforementioned problems. For example, they have suggested reducing migration by introducing flame-retardant groups into polymer chains or using polymeric flame retardants. However, to date, most technologies still rely on separate flame retardants and pigments, and there are no reports of directly attaching DOPO-type phosphorus-containing flame-retardant groups to organic chromophores to create a "pigment with built-in flame-retardant function." In other words, a pigment that simultaneously achieves both color and flame-retardant functions within a single molecule remains a gap in the field.

[0004] There are currently no effective solutions to the problems in the relevant technologies. Summary of the Invention

[0005] In view of the above, the present invention provides a perylene imide-DOPO colored flame retardant, its preparation method and application, to solve the aforementioned problems.

[0006] To solve the above problems, the specific technical solution adopted by the present invention is as follows:

[0007] According to a first aspect of the present invention, a perylene-imide-DOPO colored flame retardant is provided, the general structural formula of which is:

[0008] PDI–[N–CH2CH2–O–P(=O)(OR)(OR')]2;

[0009] Wherein, PDI represents the chromophore skeleton of perylene diimide, PDI–N– represents the nitrogen atom on the imide group in the perylene diimide molecule, –CH2-CH2–O– represents the ethylene ether bond, P(=O)(OR)(OR') represents the phosphate ester group; R and R' each independently represent two substituents on the phosphate ester group.

[0010] Preferably, the molecular structure of this peryleneimide-DOPO colored flame retardant is shown below:

[0011] .

[0012] Preferably, substituents R and R' are sequentially connected to two imide nitrogen atoms in the perylene diimide chromophore skeleton to form a disubstituted structure.

[0013] Preferably, substituent R and substituent R' are each one of alkyl, aryl, phosphorus-containing group, acyl or other functional group; the alkyl group includes methyl and ethyl; the aryl group includes phenyl or p-hydroxyphenyl; the phosphorus-containing group includes DOPO-derived group;

[0014] When substituents R and R' are alkyl, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0015]

[0016]

[0017] When substituents R and R' are phenyl, the molecular structure of perylene imide-DOPO colored flame retardants is shown below:

[0018]

[0019] When substituent R is a DOPO group and substituent R' is an alkyl group, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0020]

[0021] When substituent R is a DOPO group and substituent R' is an aryl group, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0022]

[0023] When both substituent R and substituent R' are DOPO-derived groups, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0024] .

[0025] Preferably, the substituent R and / or substituent R' contains an aromatic structure or a phosphorus element.

[0026] According to a second aspect of the present invention, a method for preparing a perylene imide-DOPO type colored flame retardant is provided, the method comprising the following steps:

[0027] S1. DOPO is reacted with formaldehyde to generate DOPO-methanol derivative, and the formaldehyde and solvent are removed by vacuum distillation to obtain a white or light-colored solid intermediate.

[0028] S2. Dissolve a white or light-colored solid intermediate in anhydrous dichloromethane, add phosphorus oxychloride and an organic base dropwise to carry out a phosphoryl chlorination reaction to generate an active intermediate of DOPO–CH2–O–P(=O)Cl2. Add 2-aminoethanol solution to the active intermediate of DOPO–CH2–O–P(=O)Cl2 dropwise at low temperature, and then heat to room temperature for several hours to form the DOPO–CH2–O–P(=O)(OCH2CH2–NH2)–Cl structure. Then wash the organic phase with dilute alkali to neutralize and remove the hydrogen chloride salt, and separate to obtain a phosphate intermediate containing a primary amine group.

[0029] S3. Equimolar amounts of perylene-3,4,9,10-tetracarboxylic dianhydride, a phosphate ester intermediate containing a primary amine group, are heated and condensed in a high-boiling solvent to generate a perylene diimide product.

[0030] S4. The perylene diimide product is heated to 130–190℃ and reacted for 6–12 hours. After amidation ring closure treatment, an imide bond is generated. After cooling through the imide bond, the product is precipitated by adding hydrochloric acid and then filtered and washed to obtain purified perylene diimide-DOPO flame retardant pigment.

[0031] According to a third aspect of the present invention, the application of a perylene imide-DOPO type colored flame retardant in flame-retardant colorants for polymer materials is provided.

[0032] Preferably, the polymer material is a polyamide or polyurethane material, which is prepared by melting and coloring a perylene imide-DOPO type colored flame retardant with the polymer.

[0033] According to a fourth aspect of the present invention, a flame-retardant colored polymer composition is provided, characterized in that the flame-retardant colored polymer composition comprises: a polyester matrix resin and a perylene-imide-DOPO colored flame retardant; the perylene-imide-DOPO colored flame retardant is uniformly mixed with the polyester matrix resin in the form of a masterbatch or additive, such that the flame-retardant colored polymer composition has a predetermined color and a limiting oxygen index of not less than 28%.

[0034] Preferably, the polyester matrix resin is a spinning-grade PET or PBT resin, and the amount of the perylene imide-DOPO colored flame retardant added is 0.1-5% of the weight of the polyester matrix resin, so that the obtained flame-retardant colored polymer composition achieves the flame-retardant rating of flame-retardant fibers while maintaining color fastness.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. Synergistic flame retardant effect: The chromophore and flame retardant groups are tightly bound at the molecular level, enabling the pigment to promote polymer charring and release phosphorus-containing free radicals during combustion, thus interrupting the combustion chain reaction and resulting in high flame retardant efficiency. At the same phosphorus content, the LOI value imparted by the pigment of this invention to the material is higher than that of systems where flame retardants and pigments are added separately.

[0037] 2. High thermal stability and color fastness: The perylene imide structure itself has excellent heat resistance, and the introduction of DOPO groups does not significantly weaken its thermal stability. Furthermore, since the flame-retardant groups are no longer added freely but chemically bonded to the colorant, the damage and compatibility issues caused by flame retardants to the colorant during high-temperature processing are avoided. Under melt blending conditions above 280℃, the colorant of this invention shows no significant decomposition or migration, and the product retains its bright color with high light and heat fastness.

[0038] 3. Excellent processing performance: The colorant of this invention can be prepared into masterbatch with uniform particle size, and disperses well in polymers without affecting the rheological and mechanical properties of the polymers. Compared with adding low-molecular-weight flame retardants alone, it avoids the potential deterioration of polymer rheology or precipitation caused by flame retardants.

[0039] 4. Versatile Functions: By altering the type of phosphate ester substituents (R and R' groups), the hydrophobicity, compatibility, and flame retardant properties of the pigment can be adjusted. For example, introducing p-hydroxyphenyl helps improve binding with polar polymers, while the double DOPO structure maximizes the flame retardant effect. This structural flexibility allows the pigments of this invention to be optimized for different polymer systems.

[0040] 5. The perylene imide-DOPO colored flame retardant provided by this invention fills the gap in the prior art and realizes a functional molecule that integrates flame retardancy and coloring, which is of great significance for improving the flame retardant performance and service stability of textile fibers and engineering plastics. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0042] Figure 1 This is a flowchart of a method for preparing a perylene imide-DOPO colored flame retardant according to an embodiment of the present invention;

[0043] Figure 2 This is a mass spectrometry analysis chromatogram of the compound prepared in Example 1 of a perylene-DOPO colored flame retardant according to an embodiment of the present invention;

[0044] Figure 3 This is a mass spectrometry analysis chromatogram of the compound prepared in Example 2 of a perylene-DOPO colored flame retardant according to an embodiment of the present invention;

[0045] Figure 4 This is a mass spectrometry analysis chromatogram of the compound prepared in Example 3 of a perylene-DOPO colored flame retardant according to an embodiment of the present invention;

[0046] Figure 5 This is a mass spectrometry analysis chromatogram of the compound prepared in Example 4 of a perylene-DOPO colored flame retardant according to an embodiment of the present invention;

[0047] Figure 6 This is a mass spectrometry analysis chromatogram of the compound prepared in Example 5 of a perylene-DOPO colored flame retardant according to an embodiment of the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0049] According to embodiments of the present invention, a perylene imide-DOPO colored flame retardant, its preparation method, and its application are provided.

[0050] The present invention will now be further described with reference to specific embodiments. According to the first embodiment of the present invention, a perylene-imide-DOPO colored flame retardant is provided, the general structural formula of which is:

[0051] PDI–[N–CH2CH2–O–P(=O)(OR)(OR')]2;

[0052] Wherein, PDI represents the chromophore skeleton of perylene diimide, PDI–N– represents the nitrogen atom on the imide group in the perylene diimide molecule, –CH2-CH2–O– represents the ethylene ether bond, P(=O)(OR)(OR') represents the phosphate ester group; R and R' each independently represent two substituents on the phosphate ester group.

[0053] As a preferred embodiment, the molecular structure of this perylene imide-DOPO colored flame retardant is shown below:

[0054] .

[0055] In a preferred embodiment, substituents R and R' are sequentially connected to two imide nitrogen atoms in the perylene diimide chromophore framework to form a disubstituted structure.

[0056] Specifically, in the above general structural formula, each of the two imide nitrogen atoms of the perylene diimide skeleton is connected to one of the above substituents, that is, both ends of the perylene diimide are connected to phosphate ester substituents containing the DOPO structure (forming a disubstituted structure).

[0057] Wherein, R and R' each independently represent two substituents on the phosphate ester group, which may be the same or different, and are selected from any of the following options:

[0058] Alkyl groups: such as methyl, ethyl, propyl, etc. (C1–C) 18 Straight-chain or branched alkyl groups (substituted or unsubstituted);

[0059] Aryl groups: such as phenyl, p-hydroxyphenyl, naphthyl, etc. (C6–C) 36 Aromatic group (substitutable, such as halogenated, alkylated, etc.);

[0060] Phosphorus-containing groups: preferably DOPO groups, i.e., 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide structures, which are connected to phosphorus atoms through their derived hydroxyl groups; other phosphorus-containing polyol groups such as trimethylolpropane can also be used.

[0061] Acyl or other functional groups: such as acyl groups with 2–18 carbons (e.g., acetyl groups) (which may further improve compatibility or stability in some cases).

[0062] In a preferred embodiment, substituent R and substituent R' are each any one of alkyl, aryl, phosphorus-containing group, acyl or other functional group; the alkyl group includes methyl and ethyl; the aryl group includes phenyl or p-hydroxyphenyl; the phosphorus-containing group includes DOPO-derived group;

[0063] (1) When substituents R and R' are alkyl, the molecular structure of perylene imide-DOPO colored flame retardants is shown below:

[0064]

[0065]

[0066] That is, each phosphate ester substituent is a dimethyl phosphate ester, which is linked to perylene imide (each molecule contains a PDI backbone and 2 methyl-substituted and 1 DOPO-substituted phosphate ester, the DOPO group provides flame retardant function, and the methyl group improves stability).

[0067] (2) When substituent R and substituent R' are phenyl, the molecular structure of perylene imide-DOPO colored flame retardants is shown below:

[0068]

[0069] That is, perylene imide substituted with diphenyl phosphate (aromatic substituents improve heat resistance and carbonization).

[0070] (3) When the substituent R is a DOPO group and the substituent R' is an alkyl group, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0071]

[0072] Each phosphate ester group is simultaneously linked to a DOPO structure and a small alkyl group, resulting in higher phosphorus content and excellent flame retardant effect.

[0073] (4) When the substituent R is a DOPO group and the substituent R' is an aryl group, the molecular structure of the perylene imide-DOPO colored flame retardant is shown below:

[0074]

[0075] Further enhance aroma and thermal stability to achieve synergistic effects of flame retardancy and oxidation resistance.

[0076] (5) When both substituent R and substituent R' are DOPO-derived groups, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below:

[0077] .

[0078] A particularly preferred structure is DOPO substitution, where both R and R' are DOPO-derived groups, and each phosphate ester group contains two DOPO structures. This compound has the highest phosphorus content and the best flame retardant performance (highest LOI value) among polymers, but its structure is relatively complex and its cost is high.

[0079] In a preferred embodiment, substituent R and / or substituent R' contain an aromatic structure or phosphorus element to fully exert the flame-retardant synergistic effect. For example, it is a preferred embodiment that at least one substituent R or R' is a DOPO-derived group; the other substituent can be an alkyl (such as methyl, ethyl), aryl (such as phenyl), or a hydroxyl-containing group (such as p-hydroxyphenyl) to adjust solubility and thermal stability.

[0080] Specifically, the aforementioned peryleneimide-DOPO pigments can be added to polymer materials as functional masterbatches or additives. For example, the pigments of this invention can be added in masterbatch form to polyester resins such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate) for melt coloring at 280–300°C. Because the chromophore and flame-retardant groups are integrated in the molecular structure of the pigments of this invention, they exhibit excellent thermal stability and compatibility during high-temperature processing. Experiments have shown that when the pigments of this invention are added under PET melt spinning doss coloring conditions, the color of the product does not undergo significant migration or decomposition, the color difference ΔE ≤ 2 (compared to masterbatches that have not undergone high-temperature processing), and the color is saturated and uniform. Simultaneously, the limiting oxygen index (LOI) of the product can reach 28–32%, significantly higher than the level of the base resin without added flame retardants (LOI is generally around 21%).

[0081] like Figure 1 As shown, according to a second embodiment of the present invention, a method for preparing a perylene imide-DOPO colored flame retardant is provided, the method comprising the following steps:

[0082] S1. DOPO is reacted with formaldehyde to generate DOPO-methanol derivative, and the formaldehyde and solvent are removed by vacuum distillation to obtain a white or light-colored solid intermediate.

[0083] Specifically, DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, containing active P–H bonds) is reacted with formaldehyde, preferably using a 37% aqueous formaldehyde solution or paraformaldehyde as the aldehyde source. In a solvent such as ethanol or propanol, the reaction is stirred at 50–80°C for several hours. The P–H bonds of DOPO undergo an addition reaction with formaldehyde to generate a DOPO–methanol derivative, namely the 9-(hydroxymethyl)-9-oxa-10-phosphaphenanthrene-10-oxide intermediate. The reaction equation is as follows: DOPO + CH₂O → DOPO–CH₂–OH. After the reaction is complete, excess formaldehyde and solvent are removed by vacuum distillation to obtain a white or light-colored solid intermediate. 31 The PNMR spectrum typically shows a characteristic peak at δ≈20–30 ppm, proving that DOPO has successfully introduced hydroxymethyl groups.

[0084] The reaction process of the white or light-colored solid intermediate is shown below:

[0085]

[0086] S2. Dissolve a white or light-colored solid intermediate in anhydrous dichloromethane, add phosphorus oxychloride and an organic base dropwise to carry out a phosphoryl chlorination reaction to generate an active intermediate of DOPO–CH2–O–P(=O)Cl2. Add 2-aminoethanol solution to the active intermediate of DOPO–CH2–O–P(=O)Cl2 dropwise at low temperature, and then heat to room temperature for several hours to form the DOPO–CH2–O–P(=O)(OCH2CH2–NH2)–Cl structure. Then wash the organic phase with dilute alkali to neutralize and remove the hydrogen chloride salt, and separate to obtain a phosphate intermediate containing a primary amine group.

[0087] Specifically, the aforementioned white or light-colored solid intermediate (DOPO–CH2–OH) is dissolved in anhydrous dichloromethane, and phosphorus oxychloride (POCl3) and an organic base (such as triethylamine) are slowly added dropwise to carry out the phosphorylation reaction. The reaction temperature is maintained at 0–5°C by controlling the dropping rate, followed by stirring at room temperature for 1–2 hours to generate the active intermediate DOPO–CH2–O–P(=O)Cl2. Next, a 2-aminoethanol (HO–CH2CH2–NH2) solution is added to the reaction system. After the addition is completed at low temperature, the temperature is raised to room temperature for several hours. The hydroxyl group in the aminoethanol molecule replaces one phosphoryl chloride atom, forming the DOPO–CH2–O–P(=O)(OCH2CH2–NH2)–Cl structure, while simultaneously releasing HCl which is captured by triethylamine to form a salt. If necessary, an appropriate amount of alcohol reagent (such as methanol, phenol, or p-hydroxyphenol) can be added to replace the remaining chlorine atom, thereby introducing the desired R group and obtaining a stable phosphate ester structure. By selecting different substituted alcohols, phosphate ester intermediates with different substituents (R) can be obtained. For example:

[0088] If methanol is added dropwise, an intermediate containing methoxy substitution is obtained: DOPO–CH2–O–P(=O)(OCH3)(OCH2CH2–NH2);

[0089] If phenol is added, a phenoxy-substituted intermediate is obtained: DOPO–CH2–O–P(=O)(OC6H5)(OCH2CH2–NH2);

[0090] If p-hydroxyphenol is added, p-hydroxyphenyl substitution is introduced;

[0091] If it is desired to introduce a second DOPO group as a substitute, the DOPO–CH2–OH intermediate can be added twice before adding aminoethanol to react with POCl3 to replace the two chlorine atoms, thereby obtaining a DOPO-disubstituted phosphate ester. Then, a small amount of aminoethanol is added to react with the residual trace amount of active chlorine to introduce a small amount of amino group (this method has a low yield, but can obtain intermediates where both R and R' are DOPO structures).

[0092] After the reaction is complete, the organic phase is washed with dilute alkali to neutralize and remove hydrogen chloride, yielding a phosphate intermediate containing a primary amine group. The phosphate intermediate is generally a viscous liquid or a semi-solid resinous substance and can be used directly in the next reaction step. Its infrared spectrum (IR) is displayed at approximately 1250–1180 cm⁻¹. -1 There is a strong P=O stretching vibration peak at 3300 cm⁻¹. -1 The presence of N–H stretching vibrations nearby confirms the presence of an amino group. The reaction process of the phosphate ester intermediate is shown in the following equation:

[0093]

[0094] S3. Equimolar amounts of perylene-3,4,9,10-tetracarboxylic dianhydride, a phosphate ester intermediate containing a primary amine group, are heated and condensed in a high-boiling solvent to generate a perylene diimide product.

[0095] Specifically, the above-mentioned amino-containing phosphate intermediate is heated and condensed with an equimolar amount of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA, also known as perylene anhydride or perylene dianhydride) in a high-boiling solvent to generate the target perylene diimide product. Polar, high-boiling solvents such as N-methylpyrrolidone (NMP), propionic acid, or imidazole are preferably used as the reaction medium, and a catalyst (such as sodium acetate or zinc acetate) is added to promote cyclization.

[0096] S4. The perylene diimide product is heated to 130–190℃ and reacted for 6–12 hours. After amidation ring closure treatment, an imide bond is generated. After cooling through the imide bond, the product is precipitated by adding hydrochloric acid and then filtered and washed to obtain purified perylene diimide-DOPO flame retardant pigment.

[0097] Specifically, the mixture is heated to 130–190°C and reacted for 6–12 hours. After amidation ring closure, each anhydride group of the perylene anhydride reacts with a primary amine to form an imide bond. After cooling, hydrochloric acid is poured in to precipitate the product, which is then filtered and reacted with sodium hydroxide at 90°C for 30 minutes. The mixture is filtered again and washed with methanol and diethyl ether to obtain the purified target perylene imide-DOPO flame retardant pigment. The perylene imide-DOPO flame retardant pigment is shown below:

[0098]

[0099] The perylene imide-DOPO flame retardant pigment product is a red or orange-red powder with the structure shown in the general formula of this invention, wherein phosphate ester substituents are attached to the imide nitrogen atoms at both ends. Typical yields are 70–85%. The product exhibits high 1H NMR spectroscopy (HNMR). 1 In HNMR, it showed signals such as δ8.0–8.5ppm (aromatic hydrogen on the perylene ring skeleton, 4H), δ7.0–7.8ppm (DOPO aromatic ring hydrogen, 8H), δ4.0–4.3ppm (N–CH2–, 2H), and δ3.5–3.8ppm (O–CH2–, 2H); 31 A single peak appears in the PNMR spectrum in the range of δ≈0 to 15 ppm (the peak varies depending on the substituent), confirming the formation of a phosphate ester bond. An infrared (IR) spectrum shows a peak at approximately 1705 cm⁻¹. -1 The characteristic absorption of imide C=O, and 1210 cm⁻¹ -1 The product exhibits a P=O absorption peak. Thermogravimetric analysis (TGA) shows that the product's 5% weight loss temperature (T5%) in air is generally above 330–360℃, indicating good thermal stability.

[0100] Through the above steps, the series of flame-retardant pigments of the general formula of this invention can be prepared. It should be noted that changing the type of substituted alcohol added in step S2 can easily adjust the structure of the phosphate ester substituents R and R' in the final product, thereby obtaining a series of target compounds with different substitutions. For target compounds containing symmetrical substituents, a compound with symmetrical substitution when R and R' are phenyl (i.e., diphenyl phosphate-substituted perylene imide) can be directly obtained by adding two equivalent amounts of substituted alcohol in a single step, followed by condensation with perylene anhydride. For asymmetrical substitution, different substituents can be introduced sequentially in two steps (e.g., first introducing a DOPO group and then another substituent), the specific order depending on the reactivity of the substituents and the desired product.

[0101] According to a third embodiment of the present invention, an application of a peryleneimide-DOPO type colored flame retardant in flame-retardant colorants for polymer materials is provided.

[0102] In a preferred embodiment, the polymer material is a polyamide or polyurethane material, which is prepared by melting and coloring a perylene imide-DOPO type colored flame retardant with the polymer to obtain the polymer material, i.e., a flame-retardant colored product.

[0103] According to a fourth embodiment of the present invention, a flame-retardant colored polymer composition is provided, comprising: a polyester matrix resin and a perylene-imide-DOPO colored flame retardant; the perylene-imide-DOPO colored flame retardant is uniformly mixed with the polyester matrix resin in the form of a masterbatch or additive, such that the flame-retardant colored polymer composition has a predetermined color and a limiting oxygen index of not less than 28%.

[0104] In a preferred embodiment, the polyester matrix resin is a spinning-grade PET or PBT resin, and the amount of the perylene imide-DOPO colored flame retardant added is 0.1-5% of the weight of the polyester matrix resin, so that the obtained flame-retardant colored polymer composition achieves the flame-retardant rating of flame-retardant fibers while maintaining color fastness.

[0105] To further illustrate the preparation and performance of the perylene imide-DOPO colored flame retardant of the present invention, specific embodiments are provided below to supplement the technical solution of this invention; however, the present invention is not limited to these embodiments.

[0106] Example 1

[0107] Preparation of peryleneimide-DOPO flame retardant pigments with R = methyl, R' = DOPO groups (i.e., compounds where R is a DOPO group and R' is an alkyl group); and mass spectrometry analysis of the peryleneimide-DOPO flame retardant pigment with R = methyl, R' = DOPO groups (MS-3a) as follows: Figure 2 As shown in the figure, "Comment" indicates a label;

[0108] Synthetic Procedure: Following the synthetic method, a phosphate intermediate containing DOPO and methoxy-substituted compounds was synthesized in a one-pot process, followed by condensation with a perylene diimide chromophore skeleton. Specifically, 31.6 g (0.15 mol) of DOPO was dissolved in anhydrous dichloromethane, and formaldehyde solution (37% aqueous solution, 13.5 mL, 0.17 mol) and 21 mL of triethylamine were added. The mixture was stirred in an ice bath for 2 h to obtain DOPO–CH2–OH. Subsequently, 15 mL (0.16 mol) of POCl3 was added dropwise, maintaining the temperature at 0–5°C. Then, 4.8 g (0.15 mol) of anhydrous methanol and 9.2 g (0.15 mol) of 2-aminoethanol were added, and the mixture was stirred at room temperature for 4 h. The reaction mixture was washed with alkali and dried to obtain the intermediate (DOPO–CH2–O–P(=O)(OCH3)(OCH2CH2–NH2)). The intermediate was further reacted with 10.8 g (0.0275 mol) of perylenetetracarboxylic dianhydride in NMP at 140 °C for 8 h. The product was purified by precipitation to obtain the target compound (i.e., the compound when R is DOPO group and R' is alkyl group), which was a red powder solid with a yield of 78%.

[0109] Structural characterization: The structure of the target compound conforms to the general structural formula of perylene imide-DOPO colored flame retardants, wherein each phosphate ester group has DOPO-CH2O- on one side and OCH3 on the other side. Elemental analysis results (%): C 62.31, H 4.25, N 4.10, P 8.32 (calculated values ​​are close to theoretical values); 1H NMR (CDCl3) δ: 8.46–8.30 (m, 8H), 7.72–7.45 (m, 16H), 4.21 (t, 4H,), 3.74 (t, 4H), 3.31 (s, 6H); 31 P NMR (CDCl3) δ: 5.2 ppm. Infrared (IR, KBr): 1708 cm⁻¹ -1 (Imidine C=O), 1601 cm -1 (Perylene ring C=C), 1215 cm -1 (P=O), 1028cm -1 (P–O–C). Thermogravimetric analysis (TGA) showed a 5% weight loss temperature of 341 ℃. Chromaticity coordinates (Lab*): L* 59.6, a* 54.8, b* 48.3 (bright orange-red).

[0110] Example 2

[0111] Preparation of peryleneimide-DOPO flame retardant pigments with R = phenyl, R' = DOPO groups (i.e., compounds where R is a DOPO group and R' is an aryl group); and mass spectrometry analysis of peryleneimide-DOPO flame retardant pigments with R = phenyl, R' = DOPO groups (MS-3b) as follows: Figure 3 As shown;

[0112] Synthetic steps: Following a similar method, the substituted alcohol in step 2 was replaced with phenol. The preparation of DOPO–CH2–OH was the same as in Example 1. Then, 14.1 g (0.15 mol) of phenol and 9.2 g (0.15 mol) of 2-aminoethanol were added sequentially to the POCl3 reaction system to obtain the phosphate intermediate DOPO–CH2–O–P(=O)(OC6H5)(OCH2CH2–NH2). This was then condensed with perylene anhydride under the same reaction conditions as in Example 1, with a yield of 74%, to obtain the target compound (i.e., the compound where R is a DOPO group and R' is an aryl group), which was a red solid.

[0113] Structural characterization: The elemental analysis results are as follows: C 66.02, H 3.98, N 3.85, P 7.45%; 1 HNMR (CDCl3) δ: 8.44–8.32 (m, 8H), 7.80–7.30 (m,24H), 4.19 (t, 4H), 3.70 (t,4H); 31 P NMR delta: 2.7 ppm. IR: 1705cm -1 (Imidine C=O), 1597 cm -1 1190 cm -1(P=O). TGA 5% weight loss temperature: 345 ℃. Chromaticity coordinates: L* 57.8, a* 56.5, b* 50.1 (the color is slightly redder than that of Example 1).

[0114] Example 3

[0115] Preparation of perylene imide-double DOPO flame retardant pigments with R=DOPO and R'=DOPO groups (i.e., double DOPO substitution); and mass spectrometry analysis of the perylene imide-double DOPO flame retardant pigments with R=DOPO and R'=DOPO groups (MS-3c) as follows: Figure 4 As shown;

[0116] Synthetic Procedure: This embodiment prepares a pigment molecule in which each phosphate ester group contains two DOPO-substituted groups. First, the DOPO–CH2–OH intermediate is prepared according to Example 1. Then, under ice bath conditions, 42.1 g (0.20 mol) of DOPO–CH2–OH is added in two batches to a mixture of POCl3 (10 mL, 0.11 mol) and triethylamine to control the reaction and generate the DOPO2–P(=O)Cl intermediate (where the two Cl groups on P are each substituted by two DOPO–CH2O– groups). Subsequently, a small amount of 2-aminoethanol (approximately 0.05 mol, equivalence ratio 1:4:1) is slowly added to replace the residual trace amounts of chlorine with aminoethanol, introducing a small amount of –OCH2CH2NH2 bonds. Condensation with perylene anhydride continues under the same conditions, but the reaction time is appropriately extended to 12 h to ensure complete reaction. The resulting target product compound is a deep red solid with a relatively low yield (approximately 50%), but a high phosphorus content.

[0117] Structural characterization: Each phosphate group in this compound is linked to two DOPO units, theoretically resulting in a molecule containing four phosphorus atoms (one from each phosphate group and one from each DOPO group). The ¹H NMR spectrum is more complex than the previously described but is generally recognizable, with increased intensity of the aromatic ring hydrogen signals. ³¹P NMR shows a main peak in the range of δ≈4–8 ppm, and a secondary peak near δ≈25 ppm (originating from the P atoms of the DOPO itself). The P=O absorption in the IR spectrum is at 1195 cm⁻¹. -1 P–Ar (DOPO-P) absorption at 1430 cm⁻¹ -1 A weak peak appears. TGA shows a 5% weight loss temperature of approximately 320℃, and a char residue rate exceeding 40% at 700℃, indicating outstanding flame-retardant charring performance. Chromaticity coordinates: L* 45.2, a* 53.6, b* 44.0 (deep red).

[0118] Example 4

[0119] Preparation of perylene imide-DOPO flame retardant pigments with R = p-hydroxyphenyl and R' = DOPO groups; and mass spectrometry analysis of the perylene imide-DOPO flame retardant pigments with R = p-hydroxyphenyl and R' = DOPO groups (MS-3d) as follows: Figure 5 As shown;

[0120] Synthesis steps: The substituted alcohol in step 2 was replaced with p-hydroxyphenol. Specifically, after the pre-reaction of DOPO–CH2–OH with POCl3, 16.5 g (0.15 mol) of p-hydroxyphenol and aminoethanol were added and reacted sequentially to obtain a phosphate intermediate containing p-hydroxyphenyl and DOPO. Then, it was condensed with perylene anhydride at 150 °C for 6 h. The target product compound obtained was a dark red solid with a yield of 70%. The obtained target product compound (i.e., peryleneimide-DOPO flame retardant pigment with R = p-hydroxyphenyl and R' = DOPO group) is shown below:

[0121]

[0122] Structural characterization: 1 H NMR (δ): 8.50–8.33 (m, 8H), 7.80–7.20 (m,24H), 6.87 (d,4H,), 4.20 (N–CH2), 3.68 (t, 4H); IR: 3380 cm -1 (Phenol O–H), 1702 cm -1 (C=O), 1185cm -1 (P=O). TGA 5% weight loss: 332 ℃. This compound exhibits increased solubility in polar solvents due to the introduction of a hydrophilic p-hydroxyl group. Chromaticity coordinates: L* 53.4, a* 58.7, b* 42.5 (red with a slightly deep purple tint).

[0123] Example 5

[0124] Preparation of perylene imide flame retardant pigments with R=ethyl, R'=phenyl (comparative example, without DOPO substitution); and mass spectrometry analysis of this R=ethyl, R'=phenyl perylene imide flame retardant pigment (MS-4) as follows: Figure 6 As shown;

[0125] Synthesis Steps: To compare and verify the importance of the DOPO group, Example 5 prepared a perylene imide phosphate pigment without DOPO substitution. DOPO was omitted; instead, phosphorus trioxide (POCl3) was directly reacted with ethanol and phenol to introduce a phosphate diester, which was then reacted with aminoethanol to obtain the (C2H5O)(C6H5O)P(=O)–OCH2CH2NH2 intermediate, which was finally condensed with perylene anhydride. The obtained target product compound was an orange solid with a yield of 82%. The obtained target product compound is shown below:

[0126]

[0127] Structural characterization: The structure of this compound is similar to the general formula of peryleneimide-DOPO flame retardant pigments, but it lacks the DOPO group. ¹H NMR: δ 8.40 (m, 8H), 7.45 (m, 10H), 4.18 (s, 4H), 3.63 (d, 4H), 1.32 (t, 6H); 31 P NMR: δ -3.8 ppm (slightly upshifted relative to the aforementioned aromatic phosphate-containing compounds). Its TGA 5% weight loss temperature is approximately 348℃, but due to the absence of DOPO char aid, the char residue at 700℃ is only 15%. Chromaticity coordinates: L* 61.0, a* 50.2, b* 52.7 (bright orange).

[0128] Examples 1–4 above are specific compound examples of the present invention, and Example 5 is a comparative example without DOPO. It can be seen that Examples 1–4, which introduce DOPO groups, all exhibit excellent flame retardant properties (high char residue, high LOI) and good thermal stability, while Comparative Example 5, although containing phosphorus, lacks the DOPO aromatic structure, and its flame retardant effect is relatively weak.

[0129] Application Examples

[0130] The colorant prepared in Example 1 of this invention was applied to the solution coloring of PET polyester fibers, and its flame retardant and coloring properties were tested. Specifically, 1000 g of polyester chips (IV=0.64) were taken, and 5 g of the colorant from Example 1 (addition amount 0.5 wt%, approximately equivalent to 0.2% of the total phosphorus content in the polymer) was added. The mixture was melt-blended at 285°C in a twin-screw extruder and spun into monofilaments. After the fibers were drawn and shaped at 130°C, their color and flame retardancy were tested. The results showed that the fibers were a bright orange-red color with no visible color difference compared to the masterbatch colorant. A spectrophotometer measured the color difference between the fibers and the original masterbatch, finding ΔE=1.3, proving that the colorant remained stable and unchanged during melt spinning. The limiting oxygen index (LOI) of the fibers was 30.1%, which meets the requirements for flame-retardant fiber grades (LOI≥28%).

[0131] Comparative Experiment 1 (Traditional Parallel Addition)

[0132] Comparative fiber A was prepared by adding commercially available perylene-imide organic pigment (phosphorus-free, 0.4 wt%, to make the fiber color similar to the example) and 10 g of DOPO flame retardant (1.0 wt%, ensuring a phosphorus content of approximately 0.2% in the PET, similar to the application example) to 1000 g of the same PET chips. The fiber was then melt-spun under the same conditions. Due to the small molecule characteristics of DOPO flame retardant, it partially decomposed and volatilized at high temperatures, and also had a certain impact on the perylene-imide pigment. Comparative fiber A had a slightly brownish tint, ΔE≈5.4, and its color was darker and less uniform than the target fiber. This indicates that in the traditional parallel addition method, the presence of the flame retardant weakens the hue of the pigment. Its LOI was approximately 28.5%, showing some improvement in flame retardancy but slightly lower than the application example fiber. This may be due to partial loss and uneven dispersion of DOPO.

[0133] Comparative Experiment 2 (without flame-retardant pigments)

[0134] Comparative fiber B was prepared by adding only 0.4 wt% perylene imide pigment (without any flame retardant) to PET for spinning. The resulting fiber had a color comparable to comparative fiber A (ΔE≈1.0, relative to the original masterbatch), but its LOI was only 21.4%, similar to pure PET, and it lacked flame retardancy. This demonstrates that pigment alone (without phosphorus) cannot improve the LOI.

[0135] Application examples and comparative experimental results are summarized in Table 1 below;

[0136] Table 1. Performance comparison of the pigments of this invention with traditional parallel addition methods.

[0137] Formula and process Color difference ΔE (compared to initial masterbatch) Limiting Oxygen Index (LOI) (%) Color Appearance Application example: PET + 0.5%, the colorant of this invention (Example 1) 1.3 30.1 The orange-red color is bright and uniform. Comparative Experiment 1: PET + 0.4% ordinary PDI pigment + 1.0% DOPO 5.4 28.5 The reddish-brown is too dark, and the hue is off. Comparative Experiment 2: PET + 0.4% ordinary PDI colorant (non-flame retardant) 1.0 21.4 Bright orange-red (non-flame retardant)

[0138] As shown in Table 1, the pigments of this invention exhibit excellent color fastness in high-temperature solution coloring (ΔE is much smaller than that of parallel addition schemes), and impart a higher LOI value to the product at the same phosphorus content. This verifies that the present invention achieves a synergistic effect of flame retardancy and coloring through structural integration: the flame-retardant groups are stably present in the pigment molecules and are not easily migrated or decomposed during processing and use, thus ensuring the coloring performance of the pigments on the one hand, and fully exerting the flame-retardant effect on the other. In contrast, traditional parallel addition of flame retardants may lead to a decrease in the thermal stability of the pigments due to sublimation or poor compatibility, and the flame-retardant efficiency may be reduced due to uneven dispersion.

[0139] In summary, the perylene imide-DOPO colored flame retardant of this invention achieves both high color fastness and high flame retardancy in polyester solution-dyed fibers, making it suitable for textile fibers and engineering plastics where aesthetics and safety are both important. For example, its application in flame-retardant carpet fibers, automotive interior parts, and electronic components will significantly improve the performance and safety of these materials.

[0140] In summary, the above-mentioned technical solution of this invention achieves a synergistic flame-retardant effect: the chromophore and flame-retardant groups are tightly bound at the molecular level, enabling the pigment to promote polymer charring and release phosphorus-containing free radicals to interrupt the combustion chain reaction during combustion, resulting in high flame-retardant efficiency. At the same phosphorus content, the pigment of this invention imparts a higher LOI value to the material than systems where flame retardants and pigments are added separately. High thermal stability and color fastness: the perylene imide structure itself has excellent heat resistance, and the introduction of DOPO groups does not significantly weaken thermal stability. Furthermore, since the flame-retardant groups are no longer added freely but are chemically bonded to the pigment, the damage and compatibility issues caused by flame retardants to the pigment during high-temperature processing are avoided. Under melt blending conditions above 280°C, the pigment of this invention shows no significant decomposition or migration, and the product retains its bright color with high light and heat fastness. Excellent processing performance: the pigment of this invention can be prepared into masterbatches with uniform particle size, dispersing well in polymers without affecting the rheological and mechanical properties of the polymer. Compared to adding low-molecular-weight flame retardants alone, this invention avoids the potential for polymer rheological degradation or precipitation caused by flame retardants. It also offers functional versatility: by changing the type of phosphate ester substituents (R and R' groups), the hydrophobicity, compatibility, and flame retardant properties of the colorant can be adjusted. For example, introducing p-hydroxyphenyl helps improve binding with polar polymers, while the double DOPO structure maximizes the flame retardant effect. This structural flexibility allows the colorants of this invention to be optimized for different polymer systems. The perylene imide-DOPO colored flame retardant provided by this invention fills a gap in the prior art, realizing a functional molecule that integrates flame retardancy and coloring, which is of great significance for improving the flame retardant properties and service stability of textile fibers and engineering plastics.

[0141] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perylene imide-DOPO type colored flame retardant, wherein the general structural formula of the perylene imide-DOPO type colored flame retardant is: PDI–[N–CH2CH2–O–P(=O)(OR)(OR')]2; in, PDI represents the chromophore skeleton of perylene diimide, PDI–N– represents the nitrogen atom on the imide group in the perylene diimide molecule, –CH2-CH2–O– represents the ethylene ether bond, P(=O)(OR)(OR') represents the phosphate ester group; R and R' each independently represent two substituents on the phosphate ester group.

2. The peryleneimide-DOPO colored flame retardant according to claim 1, characterized in that, The molecular structure of this peryleneimide-DOPO colored flame retardant is shown below: 。 3. The peryleneimide-DOPO colored flame retardant according to claim 1, characterized in that, Substituents R and R' are sequentially attached to the two imide nitrogen atoms of the perylene diimide chromophore framework to form a disubstituted structure.

4. A peryleneimide-DOPO colored flame retardant according to claim 2, characterized in that, Substituent R and substituent R' are each any one of alkyl, aryl, phosphorus-containing group, acyl or other functional group; the alkyl group includes methyl and ethyl; the aryl group includes phenyl or p-hydroxyphenyl; the phosphorus-containing group includes DOPO-derived group; When substituents R and R' are alkyl, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below: ； ； When substituents R and R' are phenyl, the molecular structure of perylene imide-DOPO colored flame retardants is shown below: ； When substituent R is a DOPO group and substituent R' is an alkyl group, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below: ； When substituent R is a DOPO group and substituent R' is an aryl group, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below: ； When both substituent R and substituent R' are DOPO-derived groups, the molecular structure of peryleneimide-DOPO colored flame retardants is shown below: 。 5. A peryleneimide-DOPO colored flame retardant according to claim 1, characterized in that, Substituent R and / or substituent R' contain aromatic structures or phosphorus elements.

6. A method for preparing a peryleneimide-DOPO type colored flame retardant, characterized in that, The method for preparing a perylene imide-DOPO colored flame retardant according to any one of claims 1-5 comprises the following steps: S1. DOPO is reacted with formaldehyde to generate DOPO-methanol derivative, and the formaldehyde and solvent are removed by vacuum distillation to obtain a white or light-colored solid intermediate. S2. Dissolve a white or light-colored solid intermediate in anhydrous dichloromethane, add phosphorus oxychloride and an organic base dropwise to carry out a phosphoryl chlorination reaction to generate an active intermediate of DOPO–CH2–O–P(=O)Cl2. Add 2-aminoethanol solution to the active intermediate of DOPO–CH2–O–P(=O)Cl2 dropwise at low temperature, and then heat to room temperature for several hours to form the DOPO–CH2–O–P(=O)(OCH2CH2–NH2)–Cl structure. Then wash the organic phase with dilute alkali to neutralize and remove the hydrogen chloride salt, and separate to obtain a phosphate intermediate containing a primary amine group. S3. Equimolar amounts of perylene-3,4,9,10-tetracarboxylic dianhydride, a phosphate ester intermediate containing a primary amine group, are heated and condensed in a high-boiling solvent to generate a perylene diimide product. S4. The perylene diimide product is heated to 130–190℃ and reacted for 6–12 hours. After amidation ring closure treatment, an imide bond is generated. After cooling through the imide bond, the product is precipitated by adding hydrochloric acid and then filtered and washed to obtain purified perylene diimide-DOPO flame retardant pigment.

7. The application of a perylene imide-DOPO colored flame retardant as described in any one of claims 1-5 in flame-retardant colorants for polymer materials.

8. The application of a peryleneimide-DOPO colored flame retardant according to claim 7 in flame-retardant colorants for polymer materials, characterized in that, The polymer material is a polyamide or polyurethane material, which is prepared by melting and coloring a perylene imide-DOPO type colored flame retardant with the polymer.

9. A flame-retardant colored polymer composition, characterized in that, The flame-retardant colored polymer composition comprises: a polyester matrix resin and a perylene-imide-DOPO colored flame retardant as described in any one of claims 1-5; the perylene-imide-DOPO colored flame retardant is uniformly mixed with the polyester matrix resin in the form of a masterbatch or additive, so that the flame-retardant colored polymer composition has a predetermined color and a limiting oxygen index of not less than 28%.

10. The flame-retardant coloring polymer composition according to claim 9, characterized in that, The polyester matrix resin is a spinning-grade PET or PBT resin, and the amount of the perylene imide-DOPO colored flame retardant added is 0.1-5% of the weight of the polyester matrix resin, so that the obtained flame-retardant colored polymer composition achieves the flame-retardant rating of flame-retardant fibers while maintaining color fastness.

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