Bio-based flame retardant, preparation method of bio-based flame retardant, flame-retardant epoxy resin and preparation method of flame-retardant epoxy resin

Abstract

The invention belongs to the field of flame retardants, and particularly relates to a bio-based flame retardant, a preparation method of the bio-based flame retardant, flame-retardant epoxy resin and a preparation method of the flame-retardant epoxy resin. The bio-based flame retardant provided by the invention is prepared by reacting phytic acid and glutamine in water. The bio-based materials phytic acid and glutamine are adopted as raw materials for preparing the flame retardant, halogen is prevented from being introduced, and the green and environment-friendly effects are achieved; the preparation process of the flame retardant is carried out in an aqueous solution, the operation is simple, and the risk is small; meanwhile, the prepared flame retardant also has an anti-ultraviolet aging effect, and can endow the epoxy resin with dual properties of flame retardance and ultraviolet aging resistance.

Description

Technical Field

[0001] This invention belongs to the field of flame retardants, and particularly relates to a bio-based flame retardant, its preparation method, a flame-retardant epoxy resin and its preparation method. Background Technology

[0002] Epoxy resin, as a thermosetting material, possesses excellent mechanical properties and is widely used in the automotive, rail transportation, and aerospace industries. However, epoxy resin has a low oxygen index, and once it comes into contact with a flame, it will burn violently, causing unpredictable disasters. Therefore, the research on flame retardants to inhibit the combustion of epoxy resin has become a widely concerned issue.

[0003] Flame retardants can be broadly classified into halogenated flame retardants and halogen-free flame retardants. Halogenated flame retardants have excellent flame-retardant effects; however, their combustion products can harm human health and the environment. Therefore, most countries have banned the use of halogenated flame retardants. Bio-based flame retardants, as a popular application of halogen-free flame retardants, have good flame-retardant effects. However, the preparation process of traditional bio-based flame retardants is relatively complex, requiring ethanol to participate in the heating reaction, which is a dangerous process.

[0004] In addition, some applications of epoxy resin need to consider the impact of sunlight on resin aging, especially the aging effect of ultraviolet light in sunlight. As aging progresses, the performance of the resin material will continue to decline until it fails. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a bio-based flame retardant, its preparation method, flame-retardant epoxy resin and its preparation method. The bio-based flame retardant provided by the present invention is prepared in an aqueous solution, the preparation process is simple and safe, and the bio-based flame retardant also has the effect of resisting ultraviolet aging, which can endow epoxy resin with dual properties of flame retardancy and resistance to ultraviolet aging.

[0006] This invention provides a bio-based flame retardant, which is made by reacting phytic acid and glutamine in water.

[0007] Preferably, the mass ratio of phytic acid to glutamine is 1:(1-5).

[0008] This invention provides a method for preparing the bio-based flame retardant described in the above technical solution, comprising the following steps:

[0009] Phytic acid and glutamine are mixed in water and heated to react. After the reaction is complete, the water is removed to obtain a bio-based flame retardant.

[0010] Preferably, the temperature of the heating reaction is 60-80°C; the stirring rate of the heating reaction is 200-400 rpm; and the heating reaction time is 2-4 hours.

[0011] Preferably, the water removal method is rotary evaporation.

[0012] Preferably, the rotational speed of the rotary evaporator is 50-100 rpm; and the temperature of the rotary evaporator is 70-80°C.

[0013] This invention provides a flame-retardant epoxy resin. The raw materials for preparing the flame-retardant epoxy resin include epoxy resin, curing agent and flame retardant. The flame retardant is the bio-based flame retardant described in the above technical solution or the bio-based flame retardant prepared by the preparation method described in the above technical solution.

[0014] Preferably, the epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin;

[0015] The curing agent is at least one of methyltetrahydrophthalic anhydride, phthalic anhydride, and methylhexahydrophthalic anhydride.

[0016] Preferably, the epoxy resin accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant; the curing agent accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant; and the flame retardant accounts for 5-30% of the total mass of epoxy resin, curing agent, and flame retardant.

[0017] This invention provides a method for preparing the flame-retardant epoxy resin described in the above technical solution, comprising the following steps:

[0018] Epoxy resin, curing agent and flame retardant are mixed and heated to cure, thus obtaining flame-retardant epoxy resin.

[0019] Compared with existing technologies, this invention provides a bio-based flame retardant, its preparation method, a flame-retardant epoxy resin, and its preparation method. The bio-based flame retardant provided by this invention is prepared by reacting phytic acid and glutamine in water. This invention uses bio-based materials phytic acid and glutamine as raw materials for preparing the flame retardant, avoiding the introduction of halogens and achieving a green and environmentally friendly effect. Furthermore, the preparation process of the flame retardant is carried out in an aqueous solution, which is simple to operate and has low risk. Simultaneously, the prepared flame retardant also has anti-ultraviolet aging properties, endowing epoxy resin with both flame-retardant and anti-ultraviolet aging properties. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1The infrared spectra of phytic acid, glutamine, and bio-based flame retardant provided in Example 1 of this invention are shown. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a bio-based flame retardant, prepared by reacting phytic acid and glutamine in water. More specifically, it is prepared by reacting phytic acid and glutamine in water, followed by dehydration.

[0024] In the bio-based flame retardant provided by the present invention, the mass ratio of phytic acid to glutamine is preferably 1:(1-5), specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0025] In the bio-based flame retardant provided by the present invention, the reaction temperature is preferably 60-80°C, specifically 60°C, 65°C, 70°C, 75°C or 80°C; the reaction time is preferably 2-4 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0026] This invention also provides a method for preparing a bio-based flame retardant, comprising the following steps:

[0027] Phytic acid and glutamine are mixed in water and heated to react. After the reaction is complete, the water is removed to obtain a bio-based flame retardant.

[0028] In the flame retardant preparation method provided by the present invention, the mass ratio of phytic acid to glutamine is preferably 1:(1-5), specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0029] In the flame retardant preparation method provided by the present invention, the water is preferably deionized water; the amount of water is preferably 10 to 20 times the total mass of phytic acid and glutamine, specifically 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 times.

[0030] In the flame retardant preparation method provided by the present invention, the preferred temperature of the heating reaction is 60-80°C, specifically 60°C, 65°C, 70°C, 75°C or 80°C; the preferred stirring rate of the heating reaction is 200-400 rpm, specifically 200 rpm, 250 rpm, 300 rpm, 350 rpm or 400 rpm; the preferred heating reaction time is 2-4 h, specifically 2 h, 2.5 h, 3 h, 3.5 h or 4 h.

[0031] In the flame retardant preparation method provided by the present invention, the dehydration method is preferably rotary evaporation; the rotation speed of the rotary evaporation is preferably 50-100 rpm, specifically 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm or 100 rpm; the temperature of the rotary evaporation is preferably 70-80℃, specifically 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃; the time of the rotary evaporation is not particularly limited, until the water has completely evaporated.

[0032] The present invention also provides a flame-retardant epoxy resin, the raw materials of which include epoxy resin, curing agent and flame retardant, wherein the flame retardant is the bio-based flame retardant described in the above technical solution or the bio-based flame retardant prepared by the preparation method described in the above technical solution.

[0033] In the flame-retardant epoxy resin provided by the present invention, the epoxy resin is preferably at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin; the curing agent is preferably at least one of methyltetrahydrophthalic anhydride, phthalic anhydride and methylhexahydrophthalic anhydride.

[0034] In the flame-retardant epoxy resin provided by this invention, the epoxy resin preferably accounts for 35-50% of the total mass of the epoxy resin, curing agent, and flame retardant, specifically 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 42.5%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; the curing agent preferably accounts for 35-50% of the total mass of the epoxy resin, curing agent, and flame retardant, specifically 35%, 36%, 37%, 38%, 39%, or 40%. The percentages are 41%, 42%, 42.5%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; the flame retardant preferably accounts for 5% to 30% of the total mass of the epoxy resin, curing agent, and flame retardant, specifically 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%.

[0035] In the flame-retardant epoxy resin provided by the present invention, the flame-retardant epoxy resin is prepared by mixing the epoxy resin, curing agent, and flame retardant, and then heating and curing them. The mixing temperature is preferably 100-110℃, specifically 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, or 110℃; the mixing speed is preferably 200-400 rpm, specifically 200 rpm, 230 rpm, 250 rpm, 270 rpm, 300 rpm, 320 rpm, 350 rpm, 370 rpm, or 400 rpm. The mixing time is preferably 1 to 5 hours, specifically 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours; the heating and curing temperature is preferably 130 to 150°C, specifically 130°C, 132°C, 135°C, 137°C, 140°C, 142°C, 145°C, 147°C, or 150°C; the heating and curing time is preferably 2 to 5 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours.

[0036] This invention also provides a method for preparing flame-retardant epoxy resin, comprising the following steps:

[0037] Epoxy resin, curing agent and flame retardant are mixed and heated to cure, resulting in flame-retardant epoxy resin;

[0038] The flame retardant is the bio-based flame retardant described in the above technical solution or the bio-based flame retardant prepared by the preparation method described in the above technical solution.

[0039] In the flame-retardant epoxy resin preparation method provided by the present invention, the epoxy resin is preferably at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin; the curing agent is preferably at least one of methyltetrahydrophthalic anhydride, phthalic anhydride and methylhexahydrophthalic anhydride.

[0040] In the flame-retardant epoxy resin preparation method provided by the present invention, the epoxy resin preferably accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant, specifically 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 42.5%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; the curing agent preferably accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant, specifically 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 42.5%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; 0%, 41%, 42%, 42.5%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; the flame retardant preferably accounts for 5% to 30% of the total mass of epoxy resin, curing agent, and flame retardant, specifically 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%.

[0041] In the flame-retardant epoxy resin preparation method provided by the present invention, the mixing temperature is preferably 100-110℃, specifically 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃ or 110℃; the mixing speed is preferably 200-400 rpm, specifically 200 rpm, 230 rpm, 250 rpm, 270 rpm, 300 rpm, 320 rpm, 350 rpm, 370 rpm or 400 rpm; the mixing time is preferably 1-5h, specifically 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h.

[0042] In the flame-retardant epoxy resin preparation method provided by the present invention, the preferred temperature for heat curing is 130-150℃, specifically 130℃, 132℃, 135℃, 137℃, 140℃, 142℃, 145℃, 147℃ or 150℃; the preferred time for heat curing is 2-5h, specifically 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h.

[0043] The technical solution provided by this invention uses bio-based materials phytic acid and glutamine as raw materials for preparing flame retardants, avoiding the introduction of halogens and achieving a green and environmentally friendly effect; moreover, the preparation process of the flame retardant is carried out in an aqueous solution, which is simple to operate and has low risk; at the same time, the prepared flame retardant also has the effect of resisting ultraviolet aging, which can endow epoxy resin with dual properties of flame retardancy and resistance to ultraviolet aging.

[0044] For clarity, the following examples and comparative examples provide a detailed description. In the examples and comparative examples provided by this invention, the epoxy resin and curing agent used in Comparative Example 1 and Examples 1-2 were provided by Huibai New Material Technology (Shanghai) Co., Ltd., with epoxy resin model AF-4149A and curing agent model AF-4149B; the epoxy resin and curing agent used in Example 3 were provided by Shanghai Maclean Biochemical Technology Co., Ltd., with epoxy resin model E-51 and curing agent phthalic anhydride.

[0045] Comparative Example 1

[0046] Weigh 5g of epoxy resin and 5g of curing agent into a beaker, stir at 200rpm for 2 hours at 100℃, then transfer to a mold and keep warm at 130℃ for 2.5 hours to obtain epoxy resin cured product.

[0047] Example 1

[0048] Weigh 5g of phytic acid and 10g of glutamine into 200ml of deionized water and react at 200rpm for 2 hours at 60℃. Transfer the reacted solution to a rotary evaporator, set the rotation speed to 50rpm and the temperature to 70℃, and obtain the bio-based flame retardant after the solvent has evaporated completely.

[0049] Infrared characterization was performed on phytic acid, glutamine, and the bio-based flame retardant prepared in this example. The results are as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that while most peak positions remained unchanged, some new peaks were also formed in the bio-based flame retardant; 1666 cm⁻¹ -1 The peak at 1523 cm⁻¹ is due to the stretching vibration of the amide group in glutamine or the stretching vibration of OPO in phytic acid; -1 NH3 was produced at the site + The new peak indicates that the bio-based flame retardant synthesized by the reaction of phytic acid and glutamine forms ionic bonds.

[0050] Weigh 4.5g of epoxy resin, 4.5g of curing agent, and 1g of the above-mentioned bio-based flame retardant into a beaker. Stir at 200rpm for 2 hours at 100℃, then transfer to a mold and keep warm at 130℃ for 2.5 hours to obtain flame-retardant epoxy resin.

[0051] Example 2

[0052] Weigh 5g of phytic acid and 15g of glutamine into 300ml of deionized water and react at 300rpm for 3 hours at 70℃. Transfer the reacted solution to a rotary evaporator, set the rotation speed to 60rpm and the temperature to 75℃. After the solvent has evaporated completely, a bio-based flame retardant is obtained.

[0053] Weigh 4.25g of epoxy resin, 4.25g of curing agent, and 1.5g of the above-mentioned bio-based flame retardant into a beaker. Stir at 350rpm for 2.5h at 105℃, then transfer to a mold and keep warm at 140℃ for 2h to obtain flame-retardant epoxy resin.

[0054] Example 3

[0055] Weigh 5g of phytic acid and 20g of glutamine into 350ml of deionized water and react at 400rpm for 4 hours at 80℃. Transfer the reacted solution to a rotary evaporator, set the rotation speed to 65rpm and the temperature to 80℃, and obtain the bio-based flame retardant after the solvent has evaporated completely.

[0056] Weigh 4g of epoxy resin, 4g of curing agent, and 2g of the above-mentioned bio-based flame retardant into a beaker. Stir at 400rpm for 3 hours at 110℃, then transfer to a mold and keep warm at 145℃ for 2 hours to obtain flame-retardant epoxy resin.

[0057] Performance Evaluation

[0058] The flame retardancy test results of the resin products in Comparative Example 1 and Examples 1-3 are shown in Table 1, and the ultraviolet transmittance test results are shown in Table 2. The results are as follows:

[0059] Table 1 Flame retardant performance test results

[0060]

[0061] Table 2 Ultraviolet Transmittance

[0062]

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bio-based flame retardant, characterized in that, It is made by reacting phytic acid and glutamine in water.

2. The bio-based flame retardant according to claim 1, characterized in that, The mass ratio of phytic acid to glutamine is 1:(1-5).

3. A method for preparing the bio-based flame retardant according to any one of claims 1 to 2, characterized in that, Includes the following steps: Phytic acid and glutamine are mixed in water and heated to react. After the reaction is complete, the water is removed to obtain a bio-based flame retardant.

4. The preparation method according to claim 3, characterized in that, The temperature of the heating reaction is 60–80°C; the stirring rate of the heating reaction is 200–400 rpm; and the heating reaction time is 2–4 h.

5. The preparation method according to claim 3, characterized in that, The method of water removal is rotary evaporation.

6. The preparation method according to claim 5, characterized in that, The rotational speed of the rotary evaporator is 50-100 rpm; the temperature of the rotary evaporator is 70-80℃.

7. A flame-retardant epoxy resin, characterized in that, The raw materials for preparing the flame-retardant epoxy resin include epoxy resin, curing agent and flame retardant, wherein the flame retardant is the bio-based flame retardant according to any one of claims 1 to 2 or the bio-based flame retardant prepared by the preparation method according to any one of claims 3 to 6.

8. The flame-retardant epoxy resin according to claim 7, characterized in that, The epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin; The curing agent is at least one of methyltetrahydrophthalic anhydride, phthalic anhydride, and methylhexahydrophthalic anhydride.

9. The flame-retardant epoxy resin according to claim 7, characterized in that, The epoxy resin accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant; the curing agent accounts for 35-50% of the total mass of epoxy resin, curing agent, and flame retardant; and the flame retardant accounts for 5-30% of the total mass of epoxy resin, curing agent, and flame retardant.

10. A method for preparing the flame-retardant epoxy resin according to any one of claims 7 to 9, characterized in that, Includes the following steps: Epoxy resin, curing agent and flame retardant are mixed and heated to cure, thus obtaining flame-retardant epoxy resin.

Images