Phosphorus-containing epoxy resin as well as preparation method and application thereof

Abstract

The invention relates to phosphorus-containing epoxy resin as well as a preparation method and application thereof, and belongs to the technical field of preparation of epoxy resin. Aiming at the problems that the traditional epoxy resin is poor in flame retardant property and the environment is seriously polluted by a halogen flame retardant, the phosphorus-containing epoxy resin is prepared by reacting ammonium phytate with a DOPO-HQ derivative according to the technical scheme of the invention. The preparation method comprises the following steps: preparing ammonium phytate from phytic acid and urea, condensing the ammonium phytate with DOPO-HQ in acetone, and adding epoxy chloropropane to carry out epoxidation reaction. And compounding the product with bisphenol A epoxy resin and 4, 4 '-diaminodiphenyl sulfone according to a specific ratio, and carrying out high-temperature curing to obtain the flame-retardant material. Experiments show that by adding a very small amount of phosphorus-containing epoxy resin, the limit oxygen index of the material reaches 29.7%, the UL-94 vertical combustion reaches the V-0 level, and compared with a traditional ammonium polyphosphate flame-retardant system, equivalent flame-retardant performance can be achieved under the condition of lower phosphorus content. The flame retardant solves the technical bottlenecks of low efficiency and large addition amount of the existing flame retardant, has the advantages of no halogen, environmental protection and bio-based sources of synthetic raw materials, and is especially suitable for the field of electronic product packaging.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resin preparation, and relates to a phosphorus-containing epoxy resin, a preparation method and an application thereof. Background Art

[0002] Epoxy resin is widely used in the new energy vehicle electronics industry due to its excellent electrical insulation properties, chemical stability, and mechanical strength. However, its low oxygen index makes it a flammable material and it easily burns under high temperatures or open flames, producing large amounts of thick smoke and toxic gases. In electronic equipment, a fire not only spreads rapidly but also produces large amounts of toxic smoke, posing a serious threat to personnel safety, while also damaging equipment and causing economic losses.

[0003] In recent years, research on flame-retardant epoxy resin electronic adhesives has focused on developing more environmentally friendly and efficient flame-retardant systems to reduce the use of halogen flame retardants, which produce toxic hydrogen halide gases and harmful substances such as polychlorinated biphenyls when burned. Researchers are committed to developing halogen-free flame retardants based on elements such as phosphorus, silicon, and nitrogen, such as DOPO derivatives. These flame retardants improve flame retardancy while reducing negative impacts on the environment and health. Through chemical modification, flame-retardant groups such as phosphorus and silicon are introduced into the epoxy resin molecular chain, forming intrinsically flame-retardant resins. These resins form a stable char layer during combustion, effectively isolating oxygen and heat.

[0004] With increasingly stringent environmental regulations and rising safety requirements, halogen-free, low-smoke, and low-toxic flame retardants are becoming the future development direction. Bio-based phosphorus-containing epoxy resins, as an important class of organophosphorus flame retardants, offer a more efficient and environmentally friendly solution for flame retardant treatment of polymer materials and hold broad application prospects. Therefore, it is necessary to research new bio-based phosphorus-containing epoxy resins and their preparation methods. Summary of the Invention

[0005] In view of this, one of the objects of the present invention is to provide a phosphorus-containing epoxy resin, a second object is to provide a method for preparing the phosphorus-containing epoxy resin, and a third object is to use the phosphorus-containing epoxy resin in the preparation of a flame-retardant phosphorus-containing epoxy resin.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a phosphorus-containing epoxy resin, wherein the phosphorus-containing epoxy resin is a compound of structural formula I, wherein the structural formula I is Among them, R1~R 10 The number of compounds of formula II is greater than or equal to 0, and the rest are NH4 + , the structural formula II is:

[0008] The structural formula of DOPO is:

[0009] Furthermore, the preparation method of the phosphorus-containing epoxy resin comprises the following steps:

[0010] (1) adding phytic acid and urea into a reactor, adding water to dissolve, heating to 60-150° C., condensing and refluxing for 20-200 min, purifying with a solvent and drying to obtain ammonium phytate;

[0011] (2) 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is added to a flask equipped with a condenser, an organic solvent is added to dissolve it, the temperature is raised to 30° C. to 100° C. to dissolve it, and then the ammonium phytate is added to react for 1 h to 10 h, and sodium hydroxide and epichlorohydrin are continuously added to react at 60 to 120° C. for 1 to 5 h, and then the solvent is removed and purified to obtain a phosphorus-containing epoxy resin.

[0012] Preferably, in step (1), the molar ratio of phytic acid to urea is 1:1 to 7;

[0013] Preferably, in step (2), the molar ratio of 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide to ammonium phytate is 2 to 6:1;

[0014] Preferably, in step (2), the organic solvent is any one or more of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene, trichlorobenzene, ethylene glycol methyl ether, ethylene glycol ethyl ether or 1,4-dioxane;

[0015] Preferably, in step (2), the molar ratio of 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide to epichlorohydrin is 1:1 to 4;

[0016] Further, the use of phosphorus-containing epoxy resin in the preparation of flame-retardant phosphorus-containing epoxy resin;

[0017] Furthermore, the present invention provides a flame retardant phosphorus-containing epoxy resin, wherein the flame retardant phosphorus-containing epoxy resin is composed of 4,4'-diaminodiphenyl sulfone, electronic grade bisphenol A epoxy resin, and phosphorus-containing epoxy resin;

[0018] Furthermore, a method for preparing a flame retardant phosphorus-containing epoxy resin comprises the following steps:

[0019] Under a nitrogen atmosphere, 4,4'-diaminodiphenyl sulfone is added to a reaction kettle, stirred and dissolved at 150-190°C, and then bisphenol A epoxy resin and the phosphorus-containing epoxy resin are added and mixed and stirred evenly. After vacuuming for 5-30 minutes, the mixture is poured into a polytetrafluoroethylene mold while hot, and first cured at 100-120°C for 1-4 hours, and then cured at 150-180°C for 2-5 hours to obtain a flame-retardant phosphorus-containing epoxy resin.

[0020] The beneficial effects of the present invention are:

[0021] The flame-retardant phosphorus-containing epoxy resin prepared using the phosphorus-containing epoxy resin of the present invention exhibits excellent flame retardancy. The performance of the flame-retardant phosphorus-containing epoxy resin with the addition of APP is consistent with that of an electronic-grade flame-retardant epoxy resin composition containing 0.1% to 1.0% phosphorus in the phosphorus-containing epoxy resin. This demonstrates that using the phosphorus-containing epoxy resin prepared by the present invention in place of APP to prepare a flame-retardant phosphorus-containing epoxy resin can reduce the phosphorus content in the electronic-grade flame-retardant epoxy resin composition without compromising the corresponding performance.

[0022] The phosphorus-containing epoxy resin of the present invention, wherein the flame-retardant phosphorus-containing epoxy resin has a phosphorus content of 0.1% to 1%, is non-drippable and non-ignitable (LOI of 26.1% to 29.7%, t1 of 1.5 to 13.5, t1 of 3.4 to 7.6, and a grade of V-0 or V-1). When the mass fraction of phosphorus is 0.5%, the limiting oxygen index can reach 28%, and the flame retardant properties can meet the requirements of electronic products. The phosphorus-containing epoxy resin flame retardant of the present invention is halogen-free and environmentally friendly, and the synthetic monomers are widely available.

[0023] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0025] Figure 1 This is the SEM micromorphology of the carbon layer in the vertical combustion test of Comparative Example 2;

[0026] Figure 2 This is the SEM microscopic morphology of the carbon layer in the vertical combustion test of Example 8. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0028] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0029] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] Example 1

[0031] A phosphorus-containing epoxy resin (PA-2HQ), the specific preparation method is as follows:

[0032] (1) Phytic acid and urea were added to a reactor in a molar ratio of 1:5, dissolved in water, heated to 100°C, and refluxed for 120 minutes. The mixture was purified with anhydrous ethanol and dried to obtain deca-ammonium phytate. The structural formula of deca-ammonium phytate is as follows:

[0033]

[0034] (2) 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), the structural formula of which is as follows:

[0035] Add to a flask equipped with a condenser, add organic solvent acetone to dissolve, heat to 60 ° C to dissolve, add ammonium phytate prepared in step (1) to react for 5 hours, continue to add sodium hydroxide and epichlorohydrin, wherein the molar ratio of DOPO-HQ to epichlorohydrin is 1:1, react at 80 ° C for 2 hours, then remove the solvent, and purify to obtain phosphorus-containing epoxy resin (PA-2HQ).

[0036] Its structure is:

[0037] Example 2

[0038] A phosphorus-containing epoxy resin (PA-3HQ), the specific preparation method is as follows:

[0039] (2) Phytic acid and urea were added to a reactor at a molar ratio of 1:4.5, dissolved in water, heated to 100°C, and refluxed for 120 minutes. The mixture was purified with anhydrous ethanol and dried to obtain nine-membered ammonium phytate. The structural formula of nine-membered ammonium phytate is as follows:

[0040]

[0041] (2) 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), the structural formula of which is as follows:

[0042] Add the DOPO-HQ to a flask equipped with a condenser, add acetone as an organic solvent to dissolve it, heat it to 60°C to dissolve it, add the ammonium phytate prepared in step (1) and react for 5 hours, continue to add sodium hydroxide and epichlorohydrin, wherein the molar ratio of DOPO-HQ to epichlorohydrin is 1:1, react at 80°C for 2 hours, then remove the solvent, and purify to obtain a phosphorus-containing epoxy resin (PA-3HQ), whose structure is:

[0043]

[0044] Example 3

[0045] A phosphorus-containing epoxy resin (PA-4HQ) is prepared by the following method:

[0046] (3) Phytic acid and urea were added to a reactor at a ratio of 1:4, dissolved in water, heated to 100°C, refluxed and reacted for 120 minutes, purified with anhydrous ethanol and dried to obtain octa-ammonium phytate. The structural formula of octa-ammonium phytate is as follows:

[0047]

[0048] (2) 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), the structural formula of which is as follows:

[0049] Add the DOPO-HQ to a flask equipped with a condenser, add acetone as an organic solvent to dissolve it, heat it to 60°C to dissolve it, add the ammonium phytate prepared in step (1) and react for 5 hours, continue to add sodium hydroxide and epichlorohydrin, wherein the molar ratio of DOPO-HQ to epichlorohydrin is 1:1, react at 80°C for 2 hours, then remove the solvent, and purify to obtain a phosphorus-containing epoxy resin (PA-4HQ), whose structure is:

[0050]

[0051] Example 4

[0052] A flame retardant phosphorus-containing epoxy resin (EP1), the specific preparation method is as follows:

[0053] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added to a reactor, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 0.83 g of the phosphorus-containing epoxy resin (PA-2HQ) prepared in Example 1 were added and mixed and stirred evenly. The mixture was evacuated for 15 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP1).

[0054] Example 5

[0055] A flame retardant phosphorus-containing epoxy resin (EP2), the specific preparation method is as follows:

[0056] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, and the mixture was heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 2.52 g of the phosphorus-containing epoxy resin (PA-2HQ) prepared in Example 1 were added and mixed and stirred evenly. After evacuation for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP2).

[0057] Example 6

[0058] A flame retardant phosphorus-containing epoxy resin (EP3), the specific preparation method is as follows:

[0059] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, and the mixture was heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of the phosphorus-containing epoxy resin (PA-2HQ) prepared in Example 1 were added and mixed and stirred evenly. The mixture was evacuated for 5 to 30 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP3).

[0060] Example 7

[0061] A flame retardant phosphorus-containing epoxy resin (EP4), the specific preparation method is as follows:

[0062] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 0.83 g of the phosphorus-containing epoxy resin (PA-3HQ) prepared in Example 2 were added and mixed and stirred evenly. After vacuuming for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP4).

[0063] Example 8

[0064] A flame retardant phosphorus-containing epoxy resin (EP5), the specific preparation method is as follows:

[0065] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 2.52 g of the phosphorus-containing epoxy resin (PA-3HQ) prepared in Example 2 were added and mixed and stirred evenly. After evacuation for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP5).

[0066] Example 9

[0067] A flame retardant phosphorus-containing epoxy resin (EP6), the specific preparation method is as follows:

[0068] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of the phosphorus-containing epoxy resin (PA-3HQ) prepared in Example 2 were added and mixed and stirred evenly. After evacuation for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP6).

[0069] Example 10

[0070] A flame retardant phosphorus-containing epoxy resin (EP7), the specific preparation method is as follows:

[0071] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 0.83 g of the phosphorus-containing epoxy resin (PA-4HQ) prepared in Example 3 were added and mixed and stirred evenly. After evacuation for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP7).

[0072] Example 11

[0073] A flame retardant phosphorus-containing epoxy resin (EP8), the specific preparation method is as follows:

[0074] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 2.52 g of the phosphorus-containing epoxy resin (PA-4HQ) prepared in Example 3 were added and mixed and stirred evenly. After vacuuming for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP8).

[0075] Example 12

[0076] A flame retardant phosphorus-containing epoxy resin (EP9), the specific preparation method is as follows:

[0077] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of the phosphorus-containing epoxy resin (PA-DOPO-HQ) prepared in Example 3 were added and mixed and stirred evenly. After evacuation for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP9).

[0078] Comparative Example 1

[0079] A flame retardant phosphorus-containing epoxy resin (EP10), the specific preparation method is as follows:

[0080] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) was added and mixed evenly. After vacuuming for 15 minutes, the mixture was poured into a polytetrafluoroethylene mold while hot and cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP10).

[0081] Comparative Example 2

[0082] A flame retardant phosphorus-containing epoxy resin (EP11), the specific preparation method is as follows:

[0083] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 12.9 g of ammonium polyphosphate (APP) were added and mixed evenly. The mixture was evacuated for 5 to 30 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP11).

[0084] Comparative Example 3

[0085] A flame retardant phosphorus-containing epoxy resin (EP12), the specific preparation method is as follows:

[0086] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of decabasic ammonium phytate were added and mixed evenly. The mixture was evacuated for 5 to 30 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP12).

[0087] Comparative Example 4

[0088] A flame retardant phosphorus-containing epoxy resin (EP13), the specific preparation method is as follows:

[0089] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of nine-membered ammonium phytate were added and mixed evenly. The mixture was evacuated for 5 to 30 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP13).

[0090] Comparative Example 5

[0091] A flame retardant phosphorus-containing epoxy resin (EP14), the specific preparation method is as follows:

[0092] Under a nitrogen atmosphere, 28.55 g of 4,4'-diaminodiphenyl sulfone (DDS) was added, heated to 170°C and stirred until the DDS was completely dissolved. 100 g of electronic-grade bisphenol A epoxy resin (DGEBA) and 4.26 g of octabasic ammonium phytate were added and mixed evenly. The mixture was vacuumed for 5 to 30 minutes and then poured into a polytetrafluoroethylene mold while hot. The mixture was first cured at 120°C for 2 hours and then at 180°C for 2 hours to prepare a flame-retardant phosphorus-containing epoxy resin (EP14).

[0093] Comparative Example 6

[0094] A flame retardant phosphorus-containing epoxy resin (EP15), the specific preparation method is as follows:

[0095] Under nitrogen atmosphere, add 28.55g of 4,4'-diaminodiphenyl sulfone (DDS), heat to 170℃ and stir until DDS is completely dissolved, add 100g of electronic grade bisphenol A epoxy resin (DGEBA) and 4.26g of HG-H and mix well. After evacuating for 5 to 30 minutes, pour into a polytetrafluoroethylene mold while hot, first cure at 120℃ for 2h, then cure at 180℃ for 2h to prepare a flame retardant phosphorus-containing epoxy resin (EP15). The compound structure of HG-H is as follows:

[0096] Example 13 Performance Test

[0097] The flame retardant phosphorus-containing epoxy resin (EP11) prepared in Comparative Example 2 was subjected to a vertical combustion test and then subjected to a SEM test. The results are shown in FIG. Figure 1The flame retardant phosphorus-containing epoxy resin (EP5) prepared in Example 8 was subjected to a vertical combustion test and then subjected to a SEM test. The results are shown in FIG. Figure 2 shown.

[0098] Figure 1 、 Figure 2 These are SEM images of the char residue after vertical combustion tests in Comparative Example 2 and Example 8. The char layer formed in Comparative Example 2 is porous, while the surface char layer in Example 8 is dense and continuous. This dense, continuous char layer effectively inhibits the ingress of oxygen and the escape of combustible gases. Furthermore, due to its low thermal conductivity, it effectively blocks heat from external flames, achieving excellent flame retardancy.

[0099] The flame retardant phosphorus-containing epoxy resins prepared in the above examples and comparative examples were tested for their performance, and the results are shown in Table 1.

[0100] Table 1 Performance test performance comparison

[0101]

[0102] As can be seen from Table 1, the flame-retardant phosphorus-containing epoxy resin prepared by using the phosphorus-containing epoxy resin of the present invention has good flame retardant properties:

[0103] 1. Comparison of basic flame retardant properties

[0104] Comparative Example 1: The epoxy resin without any flame retardant had a LOI of only 23.7%. It dripped and ignited in the UL-94 test and received no rating, proving that pure epoxy resin is flammable.

[0105] Example 4-6 (PA-2HQ series): Phosphorus content increased from 0.83g to 4.26g, LOI increased from 26.1% to 29.7%, and UL-94 rating rose from V-1 to V-0. The t1 time decreased from 13.5s to 1.5s, and the t2 time decreased from 6.7s to 3.4s, indicating that the increased phosphorus content significantly accelerated the self-extinguishing rate and improved flame retardancy.

[0106] 2.Comparison with traditional flame retardants

[0107] Comparative Example 2 (APP): The sample to which 12.9 g of ammonium polyphosphate (APP) was added had an LOI of 27.9%, a V-1 level, and t1 / t2 of 12.5 s / 8.2 s.

[0108] Example 6 (PA-2HQ): Only 4.26g of phosphorus-containing epoxy resin was required to achieve an LOI of 29.7%, a V-0 rating, and a t1 / t2 ratio of just 1.5s / 3.4s. At the same phosphorus content, this invention demonstrates a 58% higher flame retardancy than APP (with an 88% shorter t1) and achieves a higher flame retardancy rating.

[0109] 3. Structural Specificity Effects

[0110] PA-3HQ series (Examples 7-9): The highest LOI reached 31.2% (Example 9), and t1 / t2 was 1.5s / 2.4s, indicating that the steric hindrance effect of the phosphorus-containing groups may enhance the density of the carbon layer.

[0111] PA-4HQ series (Examples 10-12): Example 12 has an LOI of up to 33.7%, t1 = 0s (instantaneous self-extinguishing), setting a new record in the test system, demonstrating that the octa-ammonium phytate structure has the best phosphorus release efficiency.

[0112] 4. Comparative experimental differences

[0113] Comparative Examples 3-5: When using phosphorus-containing compounds of unknown structure, the LOI is only 26.3-26.8%, and the t1 is as long as 14.5-16.1 s, which is significantly lower than that of the examples of the present invention, highlighting the synergistic effect of DOPO-HQ and ammonium phytate.

[0114] Comparative Example 6 (HQ-H): LOI 24.9% is close to the base resin, proving that the use of hydroxyl compounds alone has no flame retardant synergy and functionalization must be achieved through phosphorus chemical bonding.

[0115] 5. Verification of technical advantages

[0116] Environmental protection: Example 6 reaches V-0 grade with a phosphorus content of 0.1%, which is 67% lower than the phosphorus content required in Comparative Example 2 (APP), and is in line with the trend of halogen-free.

[0117] Test data fully proves that the phosphorus-containing epoxy resin prepared by chemical bonding of ammonium phytate and DOPO-HQ can achieve LOI>26% and V-0 flame retardancy, and has the advantages of lower addition amount and higher efficiency compared with the traditional APP system.

[0118] This shows that using the phosphorus-containing epoxy resin prepared by the present invention instead of APP to prepare a flame-retardant phosphorus-containing epoxy resin can reduce the phosphorus content in the electronic-grade flame-retardant epoxy resin composition without affecting the corresponding properties.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A phosphorus-containing epoxy resin, characterized in that: The phosphorus-containing epoxy resin is a compound of structural formula I, and the structural formula I is: Among them, R1~R 10 The number of compounds of formula II is greater than or equal to 0, and the rest are NH4 + , the structural formula II is The structural formula of DOPO is:

2. The method for preparing the phosphorus-containing epoxy resin according to claim 1, characterized in that: The preparation method comprises the following steps: (1) adding phytic acid and urea into a reactor, adding water to dissolve, heating to 60-150° C., condensing and refluxing for 20-200 min, purifying with a solvent and drying to obtain ammonium phytate; (2) 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide is added to a flask equipped with a condenser, an organic solvent is added to dissolve it, the temperature is raised to 30° C. to 100° C. to dissolve it, and then the ammonium phytate is added to react for 1 h to 10 h, and sodium hydroxide and epichlorohydrin are continuously added to react at 60 to 120° C. for 1 to 5 h, and then the solvent is removed and purified to obtain a phosphorus-containing epoxy resin.

3. The preparation method according to claim 2, characterized in that In step (1), the molar ratio of phytic acid to urea is 1:1-7.

4. The preparation method according to claim 2, wherein: In step (2), the molar ratio of the 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide to ammonium phytate is 2 to 6:

1.

5. The preparation method according to claim 2, wherein: In step (2), the organic solvent is any one or more of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chlorobenzene, dichlorobenzene, trichlorobenzene, ethylene glycol methyl ether, ethylene glycol ethyl ether or 1,4-dioxane.

6. The preparation method according to claim 2, wherein: In step (2), the molar ratio of the 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide to epichlorohydrin is 1:1 to 4.

7. Use of the phosphorus-containing epoxy resin according to claim 1 in the preparation of a flame-retardant phosphorus-containing epoxy resin.

8. Flame retardant phosphorus-containing epoxy resin, characterized by: The flame-retardant phosphorus-containing epoxy resin is composed of 4,4'-diaminodiphenyl sulfone, electronic-grade bisphenol A epoxy resin, and the phosphorus-containing epoxy resin according to claim 1.

9. The method for preparing a flame retardant phosphorus-containing epoxy resin according to claim 8, wherein: The preparation method comprises the following steps: Under a nitrogen atmosphere, 4,4'-diaminodiphenyl sulfone is added to a reaction kettle, stirred and dissolved at 150-190°C, and then bisphenol A epoxy resin and the phosphorus-containing epoxy resin according to claim 1 are added and mixed and stirred evenly. After vacuuming for 5-30 minutes, the mixture is poured into a polytetrafluoroethylene mold while hot, and first cured at 100-120°C for 1-4 hours, and then cured at 150-180°C for 2-5 hours to obtain a flame-retardant phosphorus-containing epoxy resin.

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