Phosphaphenanthrene-containing compound, epoxy resin material and preparation method and application thereof

Abstract

The invention relates to a compound containing phosphaphenanthrene, an epoxy resin material and a preparation method and application thereof. The structure of the compound is as shown in formula (I): # imgabs0. The compound containing phosphaphenanthrene not only can endow an epoxy resin material with efficient flame retardance, but also can improve the mechanical properties, including impact strength, flexural modulus, flexural strength, elongation at break and tensile strength, of the epoxy resin material. In addition, the preparation method of the compound containing phosphaphenanthrene is simple in synthesis process, free of catalysts in the whole preparation process, simple, easy to implement, low in toxicity, low in pollution and easy to industrialize.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardants, and more specifically to a phosphine-phenanthrene-containing compound, an epoxy resin material, and a preparation method and application thereof. Background Art

[0002] As one of the most popular thermosetting resins, epoxy resin has many performance advantages, such as high mechanical strength and stiffness, excellent thermal stability and solvent resistance, excellent adhesion and electrical insulation, easy processing, and is widely used in adhesives, molded composites, electrical insulators, automobiles, electronic packaging materials, surface coatings, and aerospace. However, epoxy resin itself is flammable and brittle, which limits its application in fields requiring high flame retardancy and fracture toughness, and even poses potential safety hazards. In order to ensure the feasibility and safety of epoxy resin in practical applications, it is necessary to take into account both efficient flame retardancy and excellent mechanical properties.

[0003] In recent decades, people have been committed to improving the flame retardancy of epoxy resins. Various additive flame retardants, such as clay minerals, organosilicon compounds, metal hydroxides, carbon nanofillers, organophosphorus compounds and inorganic phosphorus compounds, have been used to enhance the flame retardancy of epoxy resins. Among them, organophosphorus compounds are considered to be the most promising due to their low smoke, low toxicity, high flame retardant efficiency through coagulation and gas phase combined action, good flame retardant coordination effect with other groups and compounds, and flexible and diverse molecular design. At present, phosphorus-containing flame retardants are an important part of the flame retardant market and the most studied flame retardant system. However, most flame retardants have common disadvantages, such as poor compatibility with epoxy resins, relatively high addition amounts are required to achieve ideal flame retardancy, easy leaching, and reduced mechanical properties of epoxy resins.

[0004] The improvement of the mechanical properties of epoxy resin is mainly achieved through various additives. For example, the toughness of epoxy resin is improved through rubber, thermoplastic polymers, etc.; the strength or modulus of epoxy resin is improved through inorganic fillers, etc. However, it is usually difficult for a single additive to improve the toughness, strength and modulus of epoxy resin at the same time.

[0005] A Chinese patent discloses a method for preparing a modified vinyl ester resin, which improves the flame retardant properties of the vinyl ester resin by adding a phosphorus-containing aryl propargyl ether compound to the vinyl ester resin. At the same time, the phosphorus-containing aryl propargyl ether compound also improves the bending strength of the vinyl ester resin to a certain extent, but it does not significantly improve the bending modulus of the vinyl ester resin and has a certain deterioration effect on the impact strength of the vinyl ester resin. In addition, the patent does not focus on the effect of the phosphorus-containing aryl propargyl ether compound on the performance of the epoxy resin.

[0006] Liang et al. (Doi:10.1002 / app.38445) prepared an anhydride curing agent containing DOPO by reacting 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphophananthrene-10-oxide with chlorinated trimellitic anhydride, which was used to modify bisphenol A epoxy resin. Although the flame retardant properties of the prepared epoxy resin material were improved, its tensile strength and impact strength were reduced.

[0007] Hu et al. (Doi: 10.1016 / j.polymdegradstab.2014.07.026) used DOPO-containing o-cresol formaldehyde novolac epoxy resin prepolymer to modify bisphenol A epoxy resin, which can improve the flame retardant properties of the epoxy resin material, but deteriorate the impact strength of the epoxy resin material.

[0008] Therefore, new technologies need to be studied to improve the flame retardancy and mechanical properties of epoxy resins. Summary of the invention

[0009] The primary purpose of the present invention is to overcome the problem that the existing epoxy resin is difficult to achieve both high flame retardancy and excellent mechanical properties, and to provide a compound containing phosphine and phenanthrene. The compound can not only impart high flame retardancy to the epoxy resin material, but also improve the mechanical properties of the epoxy resin material.

[0010] A further object of the present invention is to provide a method for preparing the above compound.

[0011] Another object of the present invention is to provide the use of the above compound in the preparation of epoxy resin materials.

[0012] Another object of the present invention is to provide an epoxy resin material.

[0013] Another object of the present invention is to provide a method for preparing an epoxy resin material.

[0014] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0015] A compound containing phosphophananthrene and phenyl propargyl ether, wherein the structure of the compound is shown in formula (I):

[0016]

[0017] The compound containing phosphine heterophenanthrene of the present invention is composed of a DOPO group and a phenyl group as a rigid unit, a methine group and a propargyl ether part as a flexible unit, and a suspended hydroxyl group. The combination of this rigid and flexible structure enables the compound to be dissolved in epoxy resin through a melting process to form a homogeneous state, thereby being uniformly dispersed in the epoxy resin material. At the same time, on the one hand, in the thermal curing process of the epoxy resin, the phenyl propargyl ether structure on the compound is retained, and mainly exists in the epoxy resin in the form of phenyl propargyl ether. The presence of phenyl propargyl ether promotes the strong intermolecular action between the compound and the epoxy resin matrix, including hydrogen bonding, π-π stacking interaction and interchain entanglement, thereby achieving effective dissipation of energy during the material fracture process, and improving the strength, toughness and modulus of the epoxy resin material. On the other hand, the rigid unit part of the compound and the physical crosslinking points formed in the epoxy resin matrix due to the strong intermolecular action can effectively limit the excessive movement of the epoxy resin network, thereby helping to improve the strength and modulus of the material. At the same time, the flexible unit part of the compound provides a certain flexibility for the network structure, allowing the material to deform more evenly when subjected to shear force and dissipate more fracture energy through intermolecular motion. In addition, the hanging hydroxyl group, as a proton donor, can accelerate the curing reaction between the epoxy group and the primary amino group; on the other hand, it can form hydrogen bonds with the epoxy resin matrix, which is beneficial to the improvement of mechanical properties.

[0018] If the hydrogen of the methine group is replaced by a rigid substituent (such as a phenyl group or a tolyl group), the resulting compound is unlikely to improve the mechanical properties of the epoxy resin material.

[0019] In addition, the phosphinophenanthrene group in the compound has flame retardant activity in both the gas phase and the condensed phase, while the phenyl propargyl ether group can first undergo Claisen rearrangement to form a benzopyran structure under high temperature conditions of combustion, and the benzopyran structure undergoes polymerization reaction and cross-linking and curing, which is also conducive to the formation of a carbon protective layer in the condensed phase. Therefore, these two groups exist in the same molecule at the same time, exerting a synergistic flame retardant effect, thereby improving the flame retardant properties of epoxy resin materials.

[0020] Specifically, the compound has a microscopic melting point of 158.8 to 164.8°C.

[0021] The preparation method of the above compound comprises the following steps: dissolving 4-(prop-2-yn-1-yloxy)benzaldehyde and DOPO (9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide) in a solvent, and reacting at 80-100° C. to obtain the compound.

[0022] Preferably, the solvent is anhydrous ethanol.

[0023] Preferably, the molar ratio of the 4-(prop-2-yn-1-yloxy)benzaldehyde to DOPO is 1:(0.9-1.1).

[0024] Preferably, the reaction time is 24 to 32 hours.

[0025] Preferably, after the reaction, purification and drying steps are also included.

[0026] More preferably, the purification comprises filtration and washing.

[0027] The invention also protects the use of the compound in preparing epoxy resin materials.

[0028] Preferably, the compound is used as a flame retardant in the preparation of epoxy resin materials.

[0029] Preferably, the compound is used as a mechanical property improving agent in the preparation of epoxy resin materials.

[0030] More preferably, the mechanical property is at least one of impact strength, flexural modulus, flexural strength, elongation at break or tensile strength.

[0031] An epoxy resin material comprises the following components in parts by weight:

[0032] 4 to 12 parts of a phosphine-phenanthrene-containing compound,

[0033] Epoxy resin prepolymer 70-78 parts,

[0034] 16 to 20 parts of curing agent.

[0035] Preferably, the mass percentage of the compound in the epoxy resin material is 4-12%.

[0036] More preferably, the mass percentage of the compound in the epoxy resin material is 4-8%. When the mass percentage of the compound containing phosphine phenanthrene is controlled within this range, the limiting oxygen index, elongation at break and impact strength of the obtained epoxy resin material are better.

[0037] More preferably, the mass percentage of the compound in the epoxy resin material is 8-12%. When the mass percentage of the compound containing phosphine phenanthrenes is controlled within this range, the obtained epoxy resin material has better tensile strength, flexural strength and flexural modulus.

[0038] Conventional epoxy resin prepolymers and curing agents in the art can be used in the present invention.

[0039] Preferably, the epoxy resin prepolymer is one or more of bisphenol A epoxy resin prepolymer, hydrogenated bisphenol A epoxy resin prepolymer, novolac epoxy resin prepolymer, bisphenol F epoxy resin prepolymer or bisphenol S epoxy resin prepolymer.

[0040] More preferably, the epoxy resin prepolymer is a bisphenol A type epoxy resin prepolymer.

[0041] Preferably, the curing agent is one or more of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, m-phenylenediamine, diethylenetriamine or triethylenetetramine.

[0042] The preparation method of the epoxy resin material comprises the following steps: mixing and dissolving the components to obtain the epoxy resin material.

[0043] Preferably, the specific process of mixing and dissolving is: adding the phosphine-containing phenanthrene compound into the epoxy resin prepolymer, stirring at 155-175° C. until the phosphine-containing phenanthrene compound is dissolved, continuing to stir at 115-130° C. for 0.5-1h, and then adding the curing agent and stirring until dissolved.

[0044] A curing method for epoxy resin material comprises the following steps: the epoxy resin material is firstly cured at 110-130°C for 1-4 hours, then cured at 140-160°C for 1-4 hours, and then cured at 170-190°C for 1-3 hours.

[0045] Preferably, the curing method comprises the following steps: the epoxy resin material is first cured at 120° C. for 2 hours, then cured at 150° C. for 2 hours, and then cured at 180° C. for 1 hour.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The phosphine-containing phenanthrene compound of the present invention can not only impart high-efficiency flame retardancy to the epoxy resin material, but also improve the mechanical properties of the epoxy resin material, including impact strength, flexural modulus, flexural strength, elongation at break and tensile strength.

[0048] (2) In addition, the preparation method of the phosphophanate-containing phenanthrene compound of the present invention has a simple synthesis process, does not require a catalyst, is simple and easy to operate, has low toxicity and low pollution, and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is an X-ray single crystal structure diagram of the phosphine-containing phenanthrene compound of Example 1 of the present invention.

[0050] Figure 2 The compound containing phosphine phenanthrene of Example 1 of the present invention 1 H NMR spectrum.

[0051] Figure 3 FTIR spectra of the phosphine-phenanthrene-containing compound of Example 1 of the present invention at room temperature and after heat treatment.

[0052] Figure 4 The graphs are the storage modulus, loss modulus and loss factor of the epoxy resin materials of Examples 2 to 4 of the present invention and Comparative Example 1 as a function of temperature, wherein: Figure 4 A in is the curve of storage modulus changing with temperature; Figure 4 B in the figure is the curve of loss modulus changing with temperature; Figure 4 C in the figure is the curve of loss factor changing with temperature. DETAILED DESCRIPTION

[0053] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0054] Example 1

[0055] This embodiment provides a phosphine-containing phenanthrene compound, the structure of which is as follows:

[0056]

[0057] The preparation method of the compound comprises the following steps: adding 4-(prop-2-yn-1-yloxy)benzaldehyde (9.61 g, 0.06 mol), DOPO (12.97 g, 0.06 mol), and anhydrous ethanol (100 mL) into a three-necked flask, reacting at 90° C. with magnetic stirring for 24 hours, cooling to room temperature, standing overnight, filtering to obtain a solid, washing it with 200 mL of ethyl acetate three times, and drying it in a vacuum drying oven at 65° C. for 24 hours to obtain a compound containing phosphine heterophenanthrene. The synthesis route is as follows:

[0058]

[0059] The X-ray single crystal structure of the compound containing phosphine phenanthrene in this embodiment is shown in FIG. Figure 1 The main crystal data of the compound containing phosphophanate: molecular formula, C 22 H 17 O4P; molecular weight, 376.32; crystal system, monoclinic; space group, P21 / n; α=90°, β=102.3502(18)°, γ=90°; Z=4; ρcalc=1.351g / cm3; Index ranges,--13≤h≤15,-4≤k≤6,-31≤l≤35; μ=1.531 mm-1; Crystal size, 0.3×0.08×0.03mm3; Radiation, CuKα(λ=1.54184); F(000)=784.0; 2θrange for data collection,

[0060] 10.374-148.292°;Goodness-of-fit on F2=1.058;Reflections collected,14621;

[0061] Independent reflections, 5787 [Rint=0.0273, Rsigma=1.100; Data / restraints / parameters, 3611 / 0 / 245; Final R indexes (all data), R1=0.0440, wR2=0.1125; Final Rindexes[I>=2σ(I)],R1=0.0393, wR2=0.1094; Largest diff.peak andhole, 0.24,-0.35.

[0062] The compound containing phosphine phenanthrene in this embodiment 1 H NMR spectrum Figure 2 As shown, the specific NMR data are as follows: 1H NMR (DMSO-d6) δ (ppm): 8.10-8.23 (2H, H15, H18), 7.38-7.97 (4H, H12, H13, H14, H20), 7.13-7.31 (4H, H8, H6, H19, H21), 6.90-6.95 (2H, H5, H9), 6.22-6.38 (1H, -OH), 5.08-5.29 (1H, H10), 4.77-4.80 (2H, H3), 3.57-3.59 (1H, H1).

[0063] The FTIR spectra of the phosphine-containing phenanthrene compound of this embodiment after heat treatment (heating at 120°C for 2 h, then heating at 150°C for 2 h, and then heating at 180°C for 1 h) are as follows: Figure 3 As shown, the sample was pressed into a KBr pellet. Figure 3 It can be seen that the C≡C bond in the phenyl propargyl ether structure is at 2118 cm -1The characteristic peak absorption intensity at 1687 cm -1 The characteristic peak absorption intensity at changes very little after thermal curing treatment, which indicates that the phenyl propargyl ether structure in the compound provided in this embodiment still exists mainly in the form of phenyl propargyl ether in the cured epoxy resin material after thermal curing treatment.

[0064] Example 2

[0065] The present embodiment provides an epoxy resin material, comprising the following components: a phosphine-containing phenanthrene compound, 4,4-diaminodiphenylmethane, and bisphenol A epoxy resin prepolymer E51 in a weight ratio of 4:19.37:76.63.

[0066] The preparation steps of the epoxy resin material are as follows: adding a phosphine-containing phenanthrene compound into a bisphenol A epoxy resin prepolymer E51, stirring at 165° C. until the phosphine-containing phenanthrene compound is dissolved, continuing to stir at 120° C. for 30 minutes, then adding 4,4-diaminodiphenylmethane, stirring until the 4,4-diaminodiphenylmethane is dissolved, and obtaining the epoxy resin material.

[0067] Example 3

[0068] This embodiment provides an epoxy resin material, which is different from Embodiment 2 in that the weight ratio of the phosphine-containing phenanthrene compound, 4,4-diaminodiphenylmethane and bisphenol A epoxy resin prepolymer E51 is 8:18.56:73.44.

[0069] Example 4

[0070] This embodiment provides an epoxy resin material, which is different from Embodiment 2 in that the weight ratio of the phosphine-containing phenanthrene compound, 4,4-diaminodiphenylmethane and bisphenol A epoxy resin prepolymer E51 is 12:17.76:70.24.

[0071] Comparative Example 1

[0072] This comparative example provides an epoxy resin material, comprising the following components: 4,4-diaminodiphenylmethane and bisphenol A epoxy resin prepolymer E51 in a weight ratio of 20.18:79.83.

[0073] The preparation steps of the epoxy resin material are as follows: 4,4-diaminodiphenylmethane is added into bisphenol A glycidyl ether resin, and the mixture is stirred at 120° C., and after the 4,4-diaminodiphenylmethane is dissolved, the epoxy resin material is obtained.

[0074] Performance Testing

[0075] The epoxy resin materials of Examples 2 to 4 and Comparative Example 1 were poured into a mold, cured at 120° C. for 2 h, 150° C. for 2 h, and 180° C. for 1 h, cooled, demolded, and polished for testing of UL-94 flame retardancy, limiting oxygen index, storage modulus, loss modulus, loss factor, tensile strength, elongation at break, flexural strength, flexural modulus, and impact strength.

[0076] The UL-94 flame retardant grade test was conducted using Jiangning CZF-3 flammability tester, with a sample size of 130×13×3mm 3 , the test standard is ASTM D3801;

[0077] The limiting oxygen index was tested on a Jiangning JF-3 oxygen index instrument according to the ASTMD 2863 test standard, and the sample size was 150 mm × 6.5 mm × 3 mm;

[0078] The storage modulus, loss modulus and loss factor were tested by three-point bending using a German Netzsch DMA242E Artemis dynamic thermomechanical analyzer. The sample size was 40×10×4mm 3 , heated from 35°C to 215°C in an air atmosphere at a heating rate of 10°C / min and a frequency of 1 Hz;

[0079] On the Shenzhen Sansi CMT6104 universal testing machine, the specimens were subjected to tensile and three-point bending tests at a speed of 5 mm / min. The tensile test standard was implemented according to GB / T 1040.2-2006, and the bending test was implemented according to GB / T9341-2008.

[0080] The simply supported unnotched impact strength test was carried out on an MTSSANS ZBC7251-B pendulum impact testing machine. The test standard was implemented in accordance with GB / T 1043.1-2008. The above test results are shown in Figure 4 and Table 1.

[0081] Figure 4 The graphs are the storage modulus, loss modulus and loss factor of the epoxy resin materials of Examples 2 to 4 of the present invention and the epoxy resin material of Comparative Example 1 as a function of temperature, wherein: Figure 4 A in is the curve of storage modulus changing with temperature; Figure 4 B in the figure is the curve of loss modulus changing with temperature; Figure 4 C in the figure is the curve of loss factor changing with temperature.

[0082] from Figure 4It can be seen from A in that the storage modulus of the epoxy resin materials of Examples 2 to 4 is significantly higher than that of the epoxy resin material of Comparative Example 1 at 50 to 100°C. In addition, as the proportion of the phosphine-containing phenanthrene compound in the epoxy resin material increases, the storage modulus increases within the range of 50 to 100°C, which indicates that the phosphine-containing phenanthrene compound of the present invention can improve the modulus and deformation resistance of the epoxy resin material.

[0083] from Figure 4 It can be seen from B that the epoxy resin materials of Examples 2 to 4 have a higher loss modulus from room temperature to glass transition temperature than the epoxy resin material of Comparative Example 1, indicating that the epoxy resin materials of Examples 2 to 4 have better damping properties, which is beneficial for converting potential destructive vibration energy into heat, indicating that the phosphine-containing phenanthrene compound of the present invention can improve the damping properties of the epoxy resin material.

[0084] from Figure 4 It can be seen from C in that the width of the relaxation peak of the epoxy resin materials of Examples 2 to 4 is the same as that of the epoxy resin material of Comparative Example 1, and the epoxy resin materials of Examples 2 to 4 are all single-phase structures, which indicates that the phosphine-containing phenanthrene compound has high compatibility with the epoxy resin and can be uniformly dispersed in the epoxy resin material.

[0085] Table 1 shows the test results of the flame retardancy and mechanical properties of the epoxy resin materials of Examples 2 to 4 of the present invention and Comparative Example 1.

[0086] Table 1 Test results of flame retardancy and mechanical properties

[0087]

[0088]

[0089] As can be seen from Table 1, the limiting oxygen index of the epoxy resin materials of Examples 2 to 4 is above 33.5%; the UL 94 flame retardant level is V-0; the tensile strength is above 90.9 MPa, the elongation at break is above 19.4%, the flexural strength is above 131.8 MPa, the flexural modulus is above 3280 MPa, and the impact strength is 33.5 kJ / m 2 The above results indicate that the phosphine-containing phenanthrene compound of the present invention can not only impart high-efficiency flame retardancy to epoxy resin materials, but also significantly improve the toughness (impact strength and elongation at break), strength (tensile strength and flexural strength) and modulus (flexural modulus) of epoxy resin materials.

[0090] It can be seen from Examples 2 to 4 that as the amount of the phosphine-containing phenanthrene compound increases, the tensile strength and flexural strength of the epoxy resin material gradually increase, while the degree of improvement of the limiting oxygen index, elongation at break, flexural modulus and impact strength first increases and then decreases. This may be because as the amount of the phosphine-containing phenanthrene compound increases, the crosslinking density of the epoxy resin material decreases.

[0091] The epoxy resin material of Comparative Example 1 does not contain the phosphine-phenanthrene-containing compound of the present invention, and has poor elongation at break and other poor properties.

[0092] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A phosphine-phenanthrene-containing compound, characterized in that: The structure of the compound is shown in formula (I):

2. A method for preparing the compound according to claim 1, characterized in that: The method comprises the following steps: dissolving 4-(prop-2-yn-1-yloxy)benzaldehyde and DOPO in a solvent, and reacting them at 80-100° C. to obtain the compound.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the 4-(prop-2-yn-1-yloxy)benzaldehyde to DOPO is 1:(0.9-1.1).

4. The preparation method according to claim 2, characterized in that: The reaction time is 24 to 32 hours.

5. Use of the compound according to claim 1 in the preparation of epoxy resin materials.

6. An epoxy resin material, characterized in that: The composition comprises the following components in parts by weight: 4 to 12 parts of the compound according to claim 1, Epoxy resin prepolymer 70-78 parts, 16 to 20 parts of curing agent.

7. The epoxy resin material according to claim 6, characterized in that: The epoxy resin prepolymer is one or more of bisphenol A epoxy resin prepolymer, hydrogenated bisphenol A epoxy resin prepolymer, novolac epoxy resin prepolymer, bisphenol F epoxy resin prepolymer or bisphenol S epoxy resin prepolymer.

8. The epoxy resin material according to claim 6, characterized in that: The curing agent is one or more of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, m-phenylenediamine, diethylenetriamine or triethylenetetramine.

9. The epoxy resin material according to claim 6, characterized in that: The mass percentage of the compound in the epoxy resin material is 4-12%.

10. A method for preparing the epoxy resin material according to any one of claims 6 to 9, characterized in that: The method comprises the following steps: mixing and dissolving the components to obtain the epoxy resin material.

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