CN104086751B - DOPO base s-triazine hydrogenated benzimidazole epoxy hardener and preparation method thereof - Google Patents

Abstract

The invention discloses a DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent and a preparation method thereof. Its preparation method first mixes solvent I, cyanuric chloride, p-hydroxybenzaldehyde and an acid-binding agent, feeds nitrogen, and heats the reaction to obtain 2,4,6-tris(4-formylphenoxy)-1, 3,5‐s-triazine ring; mix solvent Ⅱ, 2,4,6-tris-formylphenoxy-1,3,5-s-triazine ring and DOPO, blow nitrogen into it, and react to obtain DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring; DOPO aldehyde-phenoxy-1,3,5-s-triazine ring was dissolved in solvent Ⅲ and added dropwise to o-phenylenediamine and solvent Ⅲ A catalyst is added into the mixture to react to obtain a DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent. The cured product of the present invention passes the UL94V-0 level in vertical combustion, and the glass transition temperature and tensile strength are respectively increased by 12.1% and 18.2% compared with non-flame retardant epoxy resin.

Description

DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent and preparation method thereof

technical field

The invention relates to a hydrogenated benzimidazole epoxy curing agent and a preparation method thereof, in particular to a DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent and a preparation method thereof.

technical background

Epoxy resins are widely used in the fields of coatings, adhesives, and packaging materials, but ordinary epoxy resins are flammable, and their limiting oxygen index is only 19.8%. Usually, they need to be flame-retardant modified to meet the use requirements. The epoxy curing agent with flame retardant function can endow the epoxy resin with flame retardant properties, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and s-triazine ring are Rigid structure, good heat resistance, both have a certain flame retardancy, these two structures are constructed in the epoxy curing agent at the same time, and the synergistic flame retardancy of phosphorus and s-triazine ring can improve the flame retardancy efficiency and reduce the The amount of phosphorus element is used to reduce the degradation of other properties of epoxy cured products caused by the introduction of flame retardant elements. Xiong et al [Xiong, Yq, Jiang Zj, etal.Journal of Applied Polymer Science.2013,127(6):4352‐4358.] synthesized a DOPO-based s-triazine ring by the Schiff base reaction of DOPO and melamine Oxygen curing agent, its structural formula is as follows:

Adopt this curing agent to solidify o-cresol epoxy resin, when phosphorus content is 5.44wt%, epoxy resin limiting oxygen index is 35%, compared with the o-cresol epoxy resin cured by phenolic resin, glass transition temperature is 165.5°C, an increase of 22.5°C, but the 5% weight loss temperature decreased by 25°C; the first step in the preparation process uses water as a solvent, while melamine and p-hydroxybenzaldehyde have very low solubility in water, the former at 60°C The solubility in hot water is only 1.8%, and the solubility of the latter in water at 30.5°C is only 1.39g, and the preparation process of Schiff base is a reversible reaction process, and water as a solvent will inhibit the progress of the reaction process, which is not conducive to the increase in yield. Improve; second step reaction 1.76g Schiff base and 2.59g DOPO just need 100ml N,N-dimethylformamide (DMF), and used solvent amount is bigger, is unfavorable for actual production application.

Chinese invention patent CN1339525A discloses the preparation of DOPO-based s-triazine ring epoxy curing agent with the following structure from four raw materials: DOPO, melamine, formaldehyde and phenol:

The phosphorus content in this curing agent is 6.73wt%, with this curing agent curing bisphenol A epoxy resin BE501, the flame retardancy of cured product reaches UL94V-0 level, the glass transition temperature of cured product is 158 ℃, but this curing agent The preparation process adopts the melting reaction under repeated vacuum conditions, and the vacuum degree is strictly required.

Chinese invention patent CN101376665 discloses a flame retardant compound containing s-triazine structure oxaphosphine phenanthrene, its structural formula is as follows:

The compound contains phosphorus and nitrogen flame retardant elements, and can be used as a flame retardant in epoxy resin. When the addition amount is 15wt%, that is, the phosphorus content is 1.28wt%, the epoxy resin can pass the UL94V‐0 flame retardant grade, LOI was 34.2%. However, the hydroxyl group on the structure of the compound has large steric hindrance, low reactivity, and no curing effect, so it cannot be used to prepare intrinsic flame-retardant epoxy resins, and is only used as an additive flame retardant.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the prior art, to provide a DOPO-based s-triazine ring hydrogenated benzimidazole that has high curing activity for epoxy resins, good flame retardancy and little impact on the thermal stability of materials Epoxy curing agent and preparation method thereof.

Compounds containing s-triazine and DOPO structures not only have good rigidity and thermal stability, but also phosphorus-nitrogen has a certain synergistic flame retardancy. The present invention further introduces rigid hydrogenated benzimidazole groups into this type of structure, endowing it with Curing reactivity to epoxy resin; prepared by reacting cyanuric chloride, p-hydroxybenzaldehyde, o-phenylenediamine and DOPO, which have good solubility in toluene and dioxane, etc. The DOPO-based s-triazine ring benzimidazole epoxy curing agent of the present invention is a yellow powder with good solubility in low-boiling point solvents such as ethanol and ethyl acetate. The system composed of it and epoxy resin EP828 was tested by non-isothermal DSC When the temperature rises, there is an obvious curing exothermic peak. When the heating rate is 5°C/min, the peak temperature is 158°C, and it has high curing activity for epoxy resin. The DOPO-based s-triazine ring benzimidazole epoxy curing agent is used to cure the epoxy resin. When the phosphorus content of the obtained cured product is 0.7wt%, the vertical burning can pass the UL94V-0 level, the LOI can reach 33.6%, the glass transition temperature and tensile strength. The tensile strength is 12.1% and 18.2% higher than that of non-flame retardant epoxy resin.

The DOPO/s-triazine anhydride epoxy curing agent of the present invention constructs DOPO base with excellent flame retardancy, s-triazine ring with good heat resistance and hydrogenated imidazole ring with curing effect in one compound molecule at the same time, with strong molecular rigidity , used as a curing agent for epoxy resin, not only has a curing effect, but also highly efficient flame retardant, to a certain extent improve the use temperature and mechanical properties of epoxy resin.

In order to realize the object of the present invention, take following technical scheme:

A DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent has the following chemical structural formula:

The DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent is in the form of yellow powder with a molecular weight of 963.15.

The preparation method of described DOPO-based s-triazine ring hydrogenation benzimidazole epoxy curing agent comprises the steps:

1) Mix solvent I, cyanuric chloride, p-hydroxybenzaldehyde and acid-binding agent, pass nitrogen gas, heat to (50-70)°C, react under stirring for (6-10) hours, cool, filter, and filtrate Distilled under reduced pressure, the obtained solid was washed with deionized water and recrystallized with ethyl acetate to obtain white needle crystals, which were dried in vacuo to obtain 2,4,6-tris(4-formylphenoxy)-1,3,5 ‐S-triazine ring; the acid-binding agent is sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium bicarbonate or potassium carbonate; the solvent I is toluene, xylene, acetonitrile or dioxygen Hexacyclic; the molar ratio of cyanuric chloride, p-hydroxybenzaldehyde and acid binding agent is 1:2.8～3.3:2.8～6;

2) Mix solvent II, 2,4,6-tri-formylphenoxy-1,3,5-s-triazine ring and DOPO, blow nitrogen gas, and react at (80-110)°C (6- 8) hours, distilled under reduced pressure, washed, and vacuum-dried to obtain a white powdery DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring; the solvent II is acetonitrile, dioxane, xylene , isopropanol or n-butanol; the molar ratio of the 2,4,6-tri-formylphenoxy-1,3,5-s-triazine ring to DOPO is 1:2 to 2.2;

3) Mix o-phenylenediamine and solvent III, feed nitrogen, and stir until o-phenylenediamine is completely dissolved; dissolve the DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring in solvent III Add dropwise to the mixture of o-phenylenediamine and solvent III, add the catalyst after the dropwise addition, continue the reaction at (60~90)°C for (7~9) hours, and pour it into solvent IV after cooling to room temperature In, precipitate out, filter, wash filter cake, vacuum dry, obtain yellow powder, be DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent; Described catalyst is p-toluenesulfonic acid, zinc chloride, Copper chloride, aluminum trichloride or iron trichloride; Described solvent III is N,N-dimethylformamide, dimethyl sulfoxide or N-methylpyrrolidone; Described solvent IV is water, Diethyl ether or ethyl acetate; the molar ratio of DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring, o-phenylenediamine and catalyst is 1:1-1.1:0.1-0.12.

In order to further realize the object of the present invention, preferably, every mole of cyanuric chloride adds solvent I to be 2～3.50 liters. Step 1) The vacuum drying temperature is (80-90)°C, and the vacuum drying time is (10-12) hours. Add 2-3 liters of solvent II per mole of 2,4,6-tri-formylphenoxy-1,3,5-s-triazine ring. The washing described in step 2) is washed 2-3 times with ethanol and ethyl acetate respectively. In step 2), the vacuum drying temperature is (80-90)°C, and the vacuum drying time is (10-12) hours. Add 400-600ml of solvent III per mole of o-phenylenediamine; add 0.8-1.5 liters of solvent III per mole of DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring. The washed filter cake is washed with hot water at (75-85)°C. Step 3) The vacuum drying temperature is (85-95)°C, and the vacuum drying time is (20-24) hours.

Compared with the prior art, the present invention has the following effects:

The DOPO-based s-triazine ring hydrogenation benzimidazole epoxy curing agent of the present invention is used for the curing of epoxy resin, not only has higher curing activity, but also can effectively improve the flame retardancy, service temperature and mechanical properties of epoxy resin Performance, when the phosphorus content is 0.70wt%, the cured product passes the UL94V-0 level in vertical combustion, and the glass transition temperature and tensile strength are respectively increased by 12.1% and 18.2% compared with non-flame retardant epoxy resin.

Description of drawings

Fig. 1 is the FT-IR spectrum of embodiment 1 curing agent TRIDDSBI.

Fig. 2 is the ¹ H-NMR spectrum of the curing agent TRIDDSBI of Example 1.

Fig. 3 is the ³¹ P-NMR spectrum of embodiment 1 curing agent TRIDDSBI.

Fig. 4 is the DSC curve of curing epoxy resin EP828 using curing agent TRIDDSBI of Example 1.

specific implementation

In order to better understand the present invention, the present invention will be further described below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1

The first step, add 200ml of toluene and 18.5g of cyanuric chloride to the reaction kettle, after the cyanuric chloride is completely dissolved in toluene, add 35.5g of p-hydroxybenzaldehyde and 11.4g of sodium hydroxide, feed nitrogen, and heat to 50°C, reacted under stirring for 10 hours, cooled, filtered, and distilled the filtrate under reduced pressure to obtain a white solid, which was washed three times with deionized water, and then recrystallized with ethyl acetate to obtain a white needle-like crystal, which was Vacuum drying at 80°C for 12 hours gave 2,4,6-tris(4-formylphenoxy)-1,3,5-s-triazine ring, which was subjected to FT-IR, ¹ H-NMR, ¹³ C ‐NMR and MS analysis, the results obtained are consistent with the results published by Ziya Erdem Koc et al. in Journal of Hazardous Materials183, (2010): 251‐255.

In the second step, add 220ml of dioxane and 44.1g of 2,4,6-tri(4-formylphenoxy)-1,3,5-s-triazine ring into the reaction kettle, until 2,4,6 ‐Tris(4‐formylphenoxy)‐1,3,5‐s-triazine ring is completely dissolved in dioxane, add 44.3g DOPO, blow nitrogen, react under reflux for 6 hours, and remove by distillation under reduced pressure Dioxane, the resulting product was washed twice with ethanol and ethyl acetate), and dried in vacuum at 80°C for 12 hours to obtain a white powder product, which was analyzed by FT-IR and ¹ H-NMR, and found that FT-IR On the spectrum, a strong and broad peak appears at 3247cm ^-1 , which is the stretching vibration absorption peak of the hydroxyl group, the characteristic absorption peaks of the aldehyde group appear at 2833cm ^-1 and 2874cm ^-1 , and the absorption peak of the aldehyde carbonyl group appears at 1701cm- ¹ . The vibration absorption peaks of the s-triazine ring skeleton appeared at 1566cm ^-1 , 1502cm ^-1 , and 806cm ^-1 , the vibration absorption peaks of the s-triazine ring C=N appeared at 1371cm ^-1 , and the C = N appeared at 1212cm ^-1 and 1162cm ^-1 ‐O‐Ph vibrational absorption peak; ^1H ‐NMR spectrum shows multiple peaks in the chemical shift range of 5.60‐5.04ppm, which is the hydrogen atom peak of the hydroxyl group in CH‐OH, and double peaks appear in the range of 6.40～6.44ppm, which is CH The peak of the hydrogen atom connected to the carbon on the OH, the multiplet in the range of 8.38-7.01ppm is the peak of the hydrogen atom on the benzene ring, and the peak of the hydrogen atom on the aldehyde group at 9.89ppm, the area integral ratio of each absorption peak is 1 in turn: 1.89:28.05:1.92, which is consistent with the number of hydrogen atoms on the DOPO-based aldehyde phenoxy-1,3,5-s-triazine ring structure, indicating that the white powder is DOPO-based aldehyde phenoxy-1,3, 5‐s-triazine ring.

The third step is to add 11.9g o-phenylenediamine and 40ml dimethyl sulfoxide into the reaction kettle, blow nitrogen gas, and stir for 15 minutes until the o-phenylenediamine is completely dissolved; 8.8g DOPO-based aldehyde phenoxy‐1 , 3,5‐s-triazine ring was dissolved in 80ml dimethyl sulfoxide, poured into a constant pressure dropping funnel, and added dropwise to the above reaction kettle within 50 minutes, after the dropwise addition, 1.7g copper chloride was added, Raise the temperature to 80°C and react for 7 hours, cool to room temperature, pour it into 1000ml of ice water, precipitate out, filter, wash the filter cake twice with hot water at 80°C, and vacuum dry at 90°C for 24 hours to obtain yellow Powder product, productive rate is 78.9%, is DOPO base s-triazine ring hydrogenation benzimidazole epoxy curing agent, is recorded as TRIDDSBI, 5g TRIDDSBI can be dissolved in the ethyl acetate of 100ml ethanol, 120ml respectively, 25ml N,N‐ Dimethylformamide and 30ml dimethyl sulfoxide, slightly soluble in benzene and chloroform, insoluble in water.

The gained ^TRIDDSBI product is carried out FT-IR, ¹ H-NMR and ³¹ P-NMR test, gained FT-IR spectrogram is shown in accompanying drawing 1, can see from Fig. 1 that the N- H stretching vibration absorption peak, skeletal vibration absorption peak of s-triazine ring appeared at 1560cm ^-1 and 1506cm ^-1 , stretching vibration absorption peak of s-triazine ring C=N appeared at 1365cm ^-1 , 1204cm ^-1 and 1160cm The stretching vibration absorption peak of C-O-Ph appeared at ^‐1 , the stretching vibration and bending vibration absorption peaks of P‐O‐Ph appeared at 928cm ^‐1 and 752cm ^‐1 , and the P=O bond appeared at 1016cm ^‐1 The stretching vibration absorption peak.

The ¹ H-NMR spectrum of the product is shown in Figure 2, 4.31ppm on the figure is the hydrogen atom peak on the secondary amino group, 5.16-5.58ppm is the hydrogen atom peak on the-CH, 6.40ppm is the hydrogen atom peak on the hydroxyl group, 7.03-8.54ppm It is the hydrogen atom peak on the benzene ring. The peak area of each chemical shift is integrated, and the obtained peak area ratio is 1/1.47/0.86/16.15, indicating that the corresponding hydrogen atom number ratio is 2:3:2:32.

The ³¹ P-NMR spectrum of the product is shown in Figure 3, and a large chemical shift peak appears at 31.57ppm on the spectrum, indicating that there is only one chemical structure of phosphorus in the product.

According to the above analysis, it can be known that the molecular weight of the TRIDDSBI product is 963.15, and has a structural formula as shown below:

,Example 2

The first step, add 350ml of xylene and 18.5g of cyanuric chloride to the reaction kettle, then slowly add 34.2g of p-hydroxybenzaldehyde and 69g of potassium carbonate, feed nitrogen, heat to 70°C and reflux for 10 hours, cool and filter , the filtrate was distilled under reduced pressure, the resulting white solid was washed 3 times with deionized water and then recrystallized with ethyl acetate to obtain white needle crystals, which were dried in vacuum at 80°C for 12 hours to obtain 2,4,6-tri(4-aldehyde phenoxy)-1,3,5-s-triazine ring.

In the second step, add 260ml of acetonitrile and 47.5g of 2,4,6-tri(4-formylphenoxy)-1,3,5-s-triazine ring in the reaction kettle, add 44.3g of DOPO, and feed nitrogen, React at 80°C for 6 hours, remove acetonitrile by distillation under reduced pressure, wash the obtained solid twice with ethanol and ethyl acetate, and dry in vacuum at 80°C for 12 hours to obtain white powder DOPO-based aldehyde phenoxy-1,3,5-homo triazine ring.

The third step is to add 11.9g of o-phenylenediamine and 50ml of N,N-dimethylformamide (DMF) into the reaction kettle, blow in nitrogen, and stir for 10 minutes until the o-phenylenediamine is completely dissolved; 8.8g of DOPO-based Aldehyphenoxy‐1,3,5‐s-triazine ring was dissolved in 100ml of DMF and added dropwise to the reaction kettle within 50min, after the dropwise addition, 2.05g of p-toluenesulfonic acid was added, and the reaction was continued at 90°C for 8 hours , cooled to room temperature, poured it into 600ml of diethyl ether, precipitated out, filtered, washed the filter cake twice with hot water at 80°C, and dried in vacuum at 90°C for 24h to obtain a yellow powder with a yield of 74.3%. The DOPO-based s-triazine ring hydrogenation benzimidazole epoxy curing agent has the same FT-IR, ¹ H-NMR and ³¹ P-NMR spectra as the product in Example 1.

Example 3

The first step is to add 250ml of dioxane and 18.5g of cyanuric chloride into the reaction kettle, then slowly add 40.3g of p-hydroxybenzaldehyde and 53g of sodium carbonate, blow in nitrogen, heat to 70°C, and stir for 10 hours , cooled, filtered, and the filtrate was distilled under reduced pressure, and the obtained solid was washed with deionized water for 3 times and then recrystallized with ethyl acetate to obtain white needle-like crystals, which were vacuum-dried at 80°C for 12 hours to obtain 2,4,6-tri( 4‐formylphenoxy)‐1,3,5‐s-triazine ring.

The second step, add 260ml of acetonitrile in the reactor to neutralize 47.5g of 2,4,6-tris(4-formylphenoxy)-1,3,5-s-triazine ring, add 44.3g of DOPO, and blow in nitrogen , reacted at 80°C for 6 hours, distilled off acetonitrile under reduced pressure, washed the obtained solid twice with ethanol and ethyl acetate, and dried in vacuum at 80°C for 12h to obtain white powder DOPO-based aldehyde phenoxy-1,3,5 ‐S-triazine ring.

The third step is to add 11.9g of o-phenylenediamine and 50ml of N-methylpyrrolidone (NMP) into the reaction kettle, blow nitrogen into it, and stir for 10 minutes until the o-phenylenediamine is completely dissolved; The base‐1,3,5‐s-triazine ring was dissolved in 50ml of NMP and added dropwise to the reaction kettle within 50min. After the dropwise addition, 1.65g of zinc chloride was added, and the reaction was continued at 80°C for 8 hours, cooled to room temperature, and Pour it into 800ml of ethyl acetate, there is a precipitate, filter, wash the filter cake twice with hot water at 80°C, and dry it in vacuum at 90°C for 24 hours to obtain a yellow powder with a yield of 76.7%, which is DOPO-based s-triazine Ring hydrogenated benzimidazole epoxy curing agent, its FT-IR, ¹ H-NMR and ³¹ P-NMR spectra are the same as the product in Example 1.

Example 4

The first step, add 350ml of acetonitrile and 18.5g of cyanuric chloride to the reaction kettle, then slowly add 40.3g of p-hydroxybenzaldehyde and 53g of sodium carbonate, feed nitrogen, heat to 70°C, stir for 10 hours, cool, Filtrate, distill the filtrate under reduced pressure, wash the obtained solid three times with deionized water, and recrystallize with ethyl acetate to obtain white needle-like crystals, which are dried in vacuum at 80°C for 12 hours to obtain 2,4,6-tris(4- Aldehyphenoxy)-1,3,5-s-triazine ring.

In the second step, add 300ml of isobutanol and 47.5g of 2,4,6-tris(4-formylphenoxy)-1,3,5-s-triazine ring into the reactor, add 44.3g of DOPO, and blow nitrogen , reacted at 100°C for 7 hours, distilled off isobutanol under reduced pressure, washed the obtained solid twice with ethanol and ethyl acetate, dried in vacuum at 80°C for 12h, and obtained white powder DOPO-based aldehyde phenoxy-1,3, 5‐s-triazine ring.

The third step is to add 11.9g o-phenylenediamine and 50ml DMF into the reaction kettle, blow nitrogen gas, and stir for 10 minutes until the o-phenylenediamine is completely dissolved; ‐Dissolve the s-triazine ring in 100ml DMF and drop it into the reaction kettle within 50min. After the dropwise addition, add 1.5g copper chloride and 0.45g zinc chloride, continue the reaction at 80°C for 8 hours, cool to room temperature, and Pour it into 1500ml of ice water, there is precipitation, filter, wash the filter cake twice with hot water at 80°C, and dry it in vacuum at 90°C for 24 hours to obtain a yellow powder with a yield of 84.7%, which is DOPO-based s-triazine ring hydrogenation Benzimidazole epoxy curing agent, its FT-IR, ¹ H-NMR and ³¹ P-NMR spectrum are identical with embodiment 1 product.

Example 5

The first step, add 300ml of toluene and 18.5g of cyanuric chloride in the reaction kettle, then slowly add 40.3g of p-hydroxybenzaldehyde, 35g of sodium carbonate and 5g of sodium hydroxide mixed acid-binding agent, feed nitrogen, and heat to 70 Stir and react at ℃ for 8 hours, cool and filter, distill the filtrate under reduced pressure, wash the obtained solid three times with deionized water and recrystallize with ethyl acetate to obtain white needle-like crystals, which are dried in vacuum at 80°C for 12 hours to obtain 2, 4,6‐tris(4‐formylphenoxy)‐1,3,5‐s-triazine ring.

In the second step, add 300ml of n-butanol and 47.5g of 2,4,6-tris(4-formylphenoxy)-1,3,5-s-triazine ring into the reaction kettle, add 44.3g of DOPO, and blow in nitrogen , reacted at 110°C for 6 hours, distilled off n-butanol under reduced pressure, washed the obtained solid twice with ethanol and ethyl acetate, and dried in vacuum at 80°C for 12 hours to obtain white powder DOPO-based aldehyde phenoxy-1, 3,5‐s-triazine ring.

The third step is to add 11.9g o-phenylenediamine and 50ml DMF into the reaction kettle, blow nitrogen gas, and stir for 10 minutes until the o-phenylenediamine is completely dissolved; ‐Dissolve the s-triazine ring in 100ml DMF and drop it into the reaction kettle within 50min. After the dropwise addition, add 1.5g copper chloride and 0.45g zinc chloride, continue the reaction at 80°C for 8 hours, cool to room temperature, and Pour it into 1500ml of ice water, there is precipitation, filter, wash the filter cake twice with hot water at 80°C, and dry it in vacuum at 90°C for 24 hours to obtain a yellow powder with a yield of 76.7%, which is DOPO-based s-triazine ring hydrogenation Benzimidazole epoxy curing agent, its FT-IR, ¹ H-NMR and ³¹ P-NMR spectrum are identical with embodiment 1 product.

application note

30g of TRIDDSBI prepared in Example 1 and 100g of epoxy resin (the trade mark is EP828) are mixed uniformly and then sampled for DSC analysis. The heating rate is 5°C/min, 10°C/min, 15°C/min and 20°C/min, nitrogen In the atmosphere, the obtained DSC temperature rise curve is shown in Figure 4; as can be seen from Figure 4, there is an exothermic peak on each figure under different heating rates, and the peaks are 158°C, 169°C, 176°C and 181°C; The curing agent diaminodiphenylmethane (DDM) and EP828 have a curing peak temperature of 153°C when the heating rate is 5°C/min, and the curing temperature of the two for bisphenol A epoxy resin is similar, indicating that the curing performance of TRIDDSBI is similar to that of DDMs are similar.

In order to control the phosphorus content in the epoxy curing system, EP828 was co-cured with DDM and TRIDDSBI prepared in Example 1. Fix the total equivalent of N-H in the molecule of DDM and TRIDDSBI equal to the equivalent of epoxy group in the epoxy resin to prepare the cured product, and determine the amount of TRIDDSBI with the content of phosphorus. The curing conditions are 100°C for 2 hours, 150°C for 2 hours, and 180°C for 1 hour. The tensile strength of the cured product is measured according to the ISO 527-2 test method; the impact strength is measured according to the ISO 179-1 test method; thermogravimetric analysis is carried out in a nitrogen atmosphere, and the heating rate is 20°C/min; the glass transition temperature is from the German NETZSCH company DMA242C dynamic mechanical analyzer test, the peak temperature of the DMA loss tangent tanδ～temperature curve is taken as the T _g of the cured product, the sample size: 60mm×6mm×3mm, the scanning range is 50～230℃, the frequency is 1Hz, and the heating rate is 3 ℃/min, air atmosphere, three-point bending mode.

comparative example

Take 25.2g of DDM and 100g of EP828 and mix them evenly, pour them into a mold made of polytetrafluoroethylene, and solidify to prepare each test sample.

Application Example 1

Take 5.0g TRIDDSBI, 24.8g DDM and 100g EP828 and mix them evenly, pour them into a mold made of polytetrafluoroethylene, and cure them to prepare each test sample. The phosphorus content after curing is 0.37wt%.

Application Example 2

10g TRIDDSBI, 24.2g DDM and 100g EP828 were mixed evenly and poured into a mold made of polytetrafluoroethylene, and cured to prepare each test sample. The theoretical phosphorus content after curing was 0.70wt%.

The properties of the cured products obtained in Application Example 1 and Application Example 2 were compared with those of the comparative example, and the results are shown in Table 1.

Table 1 Comparison of various properties of the cured products of the embodiment and the comparative example

As can be seen from Table 1, the DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent of the present invention is used for the curing of epoxy resins, which can effectively improve the flame retardancy of epoxy resins. When the phosphorus content is 0.70wt% , the cured product passed the UL94V-0 level by vertical combustion. Compared with the comparative example, the epoxy cured product using the DOPO-based s-triazine ring hydrogenated benzimidazole epoxy curing agent not only passed a certain flame retardant grade, but also had a higher service temperature and better mechanical properties, representing the upper limit of the service temperature The glass transition temperature (T _g ) and tensile strength increased by 12.1% and 18.2%, respectively, and only the initial degradation temperature (T _5% ) decreased slightly.

As can be seen from the above, the DOPO-based s-triazine ring hydrogenation benzimidazole epoxy curing agent of the present invention has good curing performance and efficient flame retardant performance to epoxy resin, and can improve epoxy resin flame retardant performance while improving epoxy resin flame retardant performance. Improve the service temperature and mechanical properties.

Claims (10)

1. a DOPO base s-triazine hydrogenated benzimidazole epoxy hardener, it is characterised in that there is following chemical structural formula:

The preparation method of DOPO base s-triazine the most according to claim 1 hydrogenated benzimidazole epoxy hardener, it is characterised in that comprise the steps:

1) solvent I, Cyanuric Chloride, hydroxy benzaldehyde and acid binding agent are mixed, be passed through nitrogen, be heated to 50～70 DEG C, the lower reaction of stirring 6～10 hours, cooling, filtration, distill filtrate decompression, and gained solid uses re-crystallizing in ethyl acetate after using deionized water wash, obtain white needle-like crystals, vacuum drying obtains 2,4,6 three (4 aldehyde radical phenoxy groups) 1,3,5 s-triazine rings；Described acid binding agent is sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium bicarbonate or potassium carbonate；Described solvent I is toluene, dimethylbenzene, acetonitrile or dioxane；The mol ratio of Cyanuric Chloride, hydroxy benzaldehyde and acid binding agent is 1:2.8～3.3:2.8～6；

2) by solvent II, 2,4,6-tri-(4-aldehyde radical phenoxy group)-1,3,5-s-triazine ring and DOPO mixing, it is passed through nitrogen, reacts 6～8 hours at 80～110 DEG C, decompression distillation, washing, vacuum drying, obtains white powder DOPO base aldehyde radical phenoxy group 1,3,5 s-triazine ring；Described solvent II is acetonitrile, dioxane, dimethylbenzene, isopropanol or n-butyl alcohol；The mol ratio of described 2,4,6-tri-(4-aldehyde radical phenoxy group)-1,3,5-s-triazine ring and DOPO is 1:2～2.2；

3) o-phenylenediamine and solvent III being mixed, be passed through nitrogen, stirring to o-phenylenediamine is completely dissolved；By described DOPO base aldehyde radical phenoxy group 1,3,5 s-triazine rings are dissolved in solvent III, are added drop-wise in o-phenylenediamine and solvent III mixture, catalyst is added after dripping, at 60～90 DEG C, continue reaction 7～9 hours, be poured into after being cooled to room temperature in solvent IV, Precipitation, filter, washing filter cake, vacuum drying, obtaining yellow powder is DOPO base s-triazine hydrogenated benzimidazole epoxy hardener；Described catalyst is p-methyl benzenesulfonic acid, zinc chloride, copper chloride, aluminum chloride or ferric chloride；Described solvent III is N, N dimethylformamide, dimethyl sulfoxide or N methyl pyrrolidone；Described solvent IV is water, ether or ethyl acetate；The mol ratio of described DOPO base aldehyde radical phenoxy group 1,3,5 s-triazine ring, o-phenylenediamine and catalyst is 1:1～1.1:0.1～0.12.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that it is 2～3.50 liters that every mole of Cyanuric Chloride adds solvent I.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that step 1) described vacuum drying temperature is 80 90 DEG C, 10 12 hours vacuum drying time.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that；It is 2～3 liters that every mole 2,4,6 3 (4 aldehyde radical phenoxy group) 1,3,5 s-triazine ring adds solvent II.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that step 2) described in washing use ethanol and ethyl acetate to wash 2 times 3 times respectively.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that step 2) described vacuum drying temperature is 80 90 DEG C, 10 12 hours vacuum drying time.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that every mole of o-phenylenediamine adds solvent III 400～600ml；Every mole of DOPO base aldehyde radical phenoxy group 1,3,5 s-triazine ring adds 0.8 1.5 liters of solvents III.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that described washing filter cake uses the hot water of 75 85 DEG C by Cake Wash.

The preparation method of DOPO base s-triazine the most according to claim 2 hydrogenated benzimidazole epoxy hardener, it is characterised in that step 3) described vacuum drying temperature is 85 95 DEG C, 20 24 hours vacuum drying time.