A preparation method of bio-based bisphenol, bio-based epoxy resin and its preparation method and application

Abstract

The present invention discloses a preparation method of a bio-based bisphenol, a bio-based epoxy resin, a preparation method thereof, and an application thereof, belonging to the field of polymer materials. The epoxy resin is obtained by condensing cheap and readily available ferulic acid, a bio-sourced diamine, and epichlorohydrin as raw materials. The epoxy resin has a simple curing process with a curing agent, high hardness, a high glass transition temperature, good heat resistance, strong toughness, and excellent mechanical properties.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and particularly relates to a preparation method for synthesizing an epoxy resin containing an amide structure based on ferulic acid, and application of the epoxy resin in adhesives. Background Art

[0002] Epoxy resins are widely used in adhesives, adhesives, composite materials, and other fields due to their high strength, excellent solvent resistance, water and corrosion resistance, and excellent insulation properties. For decades, the precursor to the widely used epoxy resin in industry has been petroleum-based bisphenol A. However, bisphenol A may be an endocrine disruptor, posing a health hazard to humans. Consequently, the search for alternatives to bisphenol A and the development of bio-based epoxy resins have become a key focus for researchers.

[0003] There have been many reports on the research of bio-based epoxy resins in the past decade. The main sources are vegetable oils, cellulose, rosin, cardanol and lignin. Alexandra et al. synthesized guaiacol-based bisphenols and triphenols, and prepared benzoxazine materials by condensing guaiacol and vanillin with formaldehyde and furanamine (ACSSustainableChemistry&Engineering, 2021, 9(17): 5768-5775). Teng et al. condensed bio-based guaiacol and protocatechuic aldehyde with the flame retardant DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) to obtain a triphenol intermediate compound, which was then further toughened with 1,4-dibromobutane and capped with epichlorohydrin to prepare an epoxy-terminated hyperbranched flame retardant, which was used to modify bisphenol A diglycidyl ether (European Polymer Journal, 2021, 157: 110638). Shen et al. used vanillic acid and epichlorohydrin to carry out esterification and etherification reactions to obtain a derivative of epoxidized vanillic acid (EVA, a lignin depolymerization product). This derivative and epoxidized soybean oil (ESO) were used to synthesize a bio-based epoxy resin that is degradable in acidic solution (ACSS Sustainable Chemistry & Engineering, 2021, 9 (1): 438-447). Raj et al. used formaldehyde to condense cardanol to obtain a bisphenol compound containing a double long carbon chain, and etherified it with epichlorohydrin to obtain a diepoxide compound (Journal of Chemical and Pharmaceutical Research (2011), 3 (6), 127-135). Patent CN109734684 introduces a method for preparing epoxy resin by condensing salicylaldehyde and polyformaldehyde. Patent CN112961321A reports a method for preparing flame-retardant epoxy resin by condensing lignin derivative phenol, DOPO and diamine. Patent CN112851911A uses epoxidized itaconate diglycidyl ester as a triepoxy functional monomer, and synthesizes a bio-based A2+B3 type hyperbranched epoxy resin with lignin-based epoxy monomers or ordinary petrochemical-based epoxy resins, such as bisphenol S epoxy resin, bisphenol F epoxy resin, or bisphenol A epoxy resin. CN112745201 introduces a method for preparing a bio-based epoxy resin using guaiacol and fluorenone. Patent US10723684 introduces a method for preparing a bio-based epoxy resin using vanillyl alcohol and guaiacol. Patent CN111205437 introduces a method for preparing a triepoxy functional epoxy resin using resorcinol and vanillic acid through Friedel-Crafts acylation under boron trifluoride catalysis. Liu Yuan et al. prepared an amide epoxy resin using isophthalamide as the starting material (Thermosetting Resins, 2019, 34(6):6).CN111909117A provides a phthalic anhydride diisopropyl alcohol amide epoxy resin and its preparation method and application. CN106220844B uses the waste material from the production of benzyl benzoate to synthesize the polyamide curing agent product compared to the traditional polyamide epoxy resin curing agent.

[0004] The aforementioned literature and patents have proposed many novel bio-based epoxy resin preparation methods, but most of them are obtained by condensing monophenolic compounds (phenol, vanillin, guaiacol) with formaldehyde, acetone, or flame retardants, fluorenone, etc. Since formaldehyde, acetone, and flame retardants (such as DOPO) are all products obtained by non-biological methods, using these compounds to condense bio-bisphenols or polyphenols will reduce the biochar content in the final epoxy resin. In addition, the use of formaldehyde condensation to prepare bisphenols ultimately carries the risk of residual formaldehyde. Meanwhile, there are relatively few reports on epoxy resins containing amide structures, and most of these have been synthesized using non-biological raw materials or by introducing amide groups through polyamide curing agents, which may result in poor hardness and low glass transition temperature of the epoxy resin. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides a method for preparing a bio-based bisphenol, a bio-based epoxy resin, and its preparation and application. The epoxy resin is obtained through a condensation reaction using inexpensive and readily available ferulic acid, a bio-sourced diamine, and epichlorohydrin. The epoxy resin is simple to cure with a curing agent, exhibits high hardness, a high glass transition temperature, good heat resistance, strong toughness, and excellent mechanical properties.

[0006] A method for preparing an amide-containing bio-based bisphenol having a structure shown in formula (II):

[0007]

[0008] Where n is 2, 3

[0009] Ferulic acid and bio-based diamine undergo an amidation reaction in the presence of a condensing agent to obtain a bio-based bisphenol as shown in formula (II);

[0010] The condensing agent is benzotriazole-1-bis(trimethylamino)phosphine-hexafluorophosphate, dicyclohexylcarbodiimide or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. The molar ratio of ferulic acid to bio-based diamine is 2:1 to 2.5:1.

[0011] The specific operation steps are as follows: ferulic acid is dissolved in N,N-dimethylformamide and triethylamine, and then the solution is placed in an ice bath to cool. Then, a bio-derived diamine (the diamine can be 1,4-butanediamine or 1,5-pentanediamine) is added, followed by a condensing agent (the condensing agent can be benzotriazole-1-bis(trimethylamino)phosphine-hexafluorophosphate (BOP), dicyclohexylcarbodiimide (DCC) or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) in dichloromethane. The mixture is stirred at 0°C for 30 minutes and then at room temperature for 2 hours. The dichloromethane is removed by rotary evaporation and the solution is diluted with 150 ml of water. The product is extracted with ethyl acetate. The extract is washed with 1N hydrochloric acid solution, water, 1M sodium bicarbonate solution and water in sequence. The organic layer is collected, dried over anhydrous magnesium sulfate, filtered, rotary evaporated, and finally dried in a vacuum drying oven. A yellow solid is obtained, which is the bio-based bisphenol containing amide.

[0012] A bio-based epoxy resin monomer containing amide, having a structure shown in formula (I):

[0013]

[0014] Where n is 2, 3

[0015] The bio-based epoxy resin monomer shown in formula (I) is prepared by using the bio-based bisphenol shown in formula (II).

[0016] A method for preparing an amide-containing bio-based epoxy resin monomer comprises reacting a bio-based bisphenol represented by formula (II) with epichlorohydrin under the catalysis of a base to generate a bio-based epoxy compound represented by formula (I); the base is potassium carbonate, dimethylaminopyridine, tetrabutylammonium bromide, and triethylamine.

[0017] Preferably, the ratio of the bio-based bisphenol represented by formula (II) to epichlorohydrin is 1:16 to 1:26.

[0018] Preferably, the bio-based epoxy resin monomer is mixed with a curing agent to obtain a bio-based epoxy resin, wherein the curing agent is 1,5-pentanediamine, Primine TM 1074、Priamine TM 1075、Priamine TM One or a mixture of 1071.

[0019] The specific operating steps of the preparation method of the above-mentioned bio-based epoxy resin monomer are as follows: at room temperature, dissolve the amide-containing bio-based bisphenol in epichlorohydrin, add a base (the base can be potassium carbonate, dimethylaminopyridine, tetrabutylammonium bromide, triethylamine) as a catalyst, react at 80°C for 2 hours, cool to room temperature, slowly add a sodium hydroxide (40% wt.) aqueous solution, stir at room temperature for 3 hours, extract with ethyl acetate, wash with saturated brine, dry, and spin-dry to obtain a khaki powder, i.e., the amide-containing bio-based epoxy resin monomer.

[0020] The curing method of the bio-based epoxy resin comprises the following steps: firstly dissolving the bio-based epoxy resin monomer and the curing agent (the curing agent is diamine, 1,5-pentanediamine or a mixture thereof) in chloroform at a molar ratio of 2:1, stirring the mixture in a reaction bottle at 80°C for 2 minutes to mix them evenly, then degassing the mixture and removing the chloroform under reduced pressure, transferring the mixture to a mold using a glass dropper, curing the mixture at 80°C for 4 hours, and then curing the mixture at 120°C for 20 hours to obtain the epoxy resin.

[0021] The present invention proposes condensing ferulic acid, a cheap and readily available bio-sourced raw material, with a bio-sourced diamine, followed by further condensation with epichlorohydrin, to produce an epoxy compound with a high biocarbon content. This epoxy compound can then be cured with bio-sourced diamine and 1,5-pentanediamine to produce a bio-based epoxy resin containing up to 90% biocarbon. The bio-based bisphenol and bio-based epoxy resin routes of the present invention are as follows:

[0022]

[0023] The raw materials ferulic acid, bio-derived diamine, diamine, and 1,5-pentanediamine used in the preparation of the epoxy resin in this application are all bio-based products with high biocarbon content. The epoxy resin prepared using these compounds as raw materials has the characteristic of high biocarbon content.

[0024] The ratio of the epoxy value of the amide-containing bio-based epoxy resin monomer to the amine value of the dimeramine Priamine 1074 is 2:1;

[0025]

[0026] Y is the mass of the added internal standard tetrachloroethane, and Z is the peak area ratio of the characteristic peak of tetrachloroethane to the characteristic peak of epoxy in NMR.

[0027] A bio-based epoxy resin containing amide for use in adhesives.

[0028] Beneficial effects

[0029] (1) The present invention uses biologically derived ferulic acid and diamine as raw materials, which have the advantages of being cheap and readily available.

[0030] (2) The route for synthesizing bio-based bisphenols is simple and has high yield.

[0031] (3) The curing agent used is also a bio-derived diamine (Primine1074, Priamine TM 1075;Priamine TM 1071) and 1,5-pentanediamine.

[0032] (4) The obtained epoxy resin containing amide structure has high biochar content, high hardness, high glass transition temperature and excellent mechanical properties.

[0033] (5) The prepared bio-based epoxy resin adhesive has excellent properties such as green environmental protection, good water resistance, corrosion resistance, and low raw material price, which is conducive to industrial production.

[0034] In summary, compared with existing epoxy resins, the present invention has the characteristics of being green and non-toxic, having good biocompatibility, novel structure, simple synthesis process and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein

[0036] Figure 1 :Containing amide bio-based bisphenol 1a 1 HNMR spectra

[0037] Figure 2 :Containing amide bio-based bisphenol 2a 1 HNMR spectra

[0038] Figure 3 :Amide-containing bio-based epoxy resin monomer 1b 1 HNMR spectra

[0039] Figure 4 :Amide-containing bio-based epoxy resin monomer 2b 1 H NMR spectra

[0040] Figure 5 :Determination of epoxy value of bio-based epoxy resin monomer 1b 1 H NMR spectra DETAILED DESCRIPTION

[0041] The present invention can be further illustrated by the following examples, which are intended to illustrate rather than limit the present invention. Anyone skilled in the art will appreciate that these examples are not intended to limit the present invention in any way and that appropriate modifications and data conversions may be made thereto without violating the spirit of the present invention or departing from the scope of the present invention.

[0042] The H NMR spectra involved in the examples were measured using a Bruker Ascend™-400 H NMR spectrometer produced by Bruker Corporation, and the deuterated reagents used were deuterated chloroform (CDCl 3 ) and deuterated dimethyl sulfoxide (DMSO-d 6 ).

[0043] The raw materials (unlabeled) used in the following examples were purchased from Shanghai San Chemical Co., Ltd.

[0044] Synthesis of bio-based bisphenols

[0045] Example 1a:

[0046] In a 100 mL reaction flask, ferulic acid (3.88 g, 20 mmol, 2 eq.) and triethylamine (1.4 mL, 10 mmol, 1 eq.) were dissolved in 20 mL of N,N-dimethylformamide at room temperature. The flask was then placed in an ice bath and 1,4-butanediamine (1 mL, 10 mmol, 1 eq.) was slowly added dropwise. This was followed by the slow addition of 20 mL of a dichloromethane solution of BOP (4 g, 10 mmol, 1 eq.). During the addition, floccules formed, and the color of the reaction solution gradually changed from yellow to reddish-brown. The reaction solution was placed in an ice bath at 0°C and stirred for 30 minutes, then brought to room temperature and stirred for 2 hours. Upon completion of the reaction, the solution returned to yellow, and the floccules disappeared. The dichloromethane was then removed under reduced pressure, and the solution was diluted with 150 mL of water. The product was extracted with ethyl acetate. The extract was washed sequentially with 1N hydrochloric acid, water, 1M sodium bicarbonate, and water, dried over magnesium sulfate, filtered, and evaporated. Finally, it was dried in a vacuum oven. The amide-containing bio-based bisphenol 1a was obtained as a yellow solid in a 90% yield. 1 HHNMR(400MHz,DMSO-d6)δ9.41(s,2H),7.94-7.92(t,2H),7.30-7.26(d,2H),7.09(s,2H),6.96-6.9 4(d,2H),6.67-6.75(d,2H),6.43-6.39(d,2H),3.77(s,6H),3.09-3.03(m,4H),1.48-1.43(m,4H).As attached Figure 1 shown.

[0047] Example 2a:

[0048] In a 100 mL reaction flask, ferulic acid (3.88 g, 20 mmol, 2 eq.) and triethylamine (1.4 mL, 10 mmol, 1 eq.) were dissolved in 20 mL of N,N-dimethylformamide at room temperature. The flask was then placed in an ice bath and 1,5-pentanediamine (1.17 mL, 10 mmol, 1 eq.) was slowly added dropwise. This was followed by the slow dropwise addition of 20 mL of a dichloromethane solution of BOP (4 g, 10 mmol, 1 eq.). During the addition, floccules formed, and the color of the reaction solution gradually changed from yellow to reddish-brown. The reaction solution was placed in an ice bath at 0°C and stirred for 30 minutes, then brought to room temperature and stirred for 2 hours. Upon completion of the reaction, the solution returned to yellow, and the floccules disappeared. The dichloromethane was then removed under reduced pressure, and the solution was diluted with 150 mL of water. The product was extracted with ethyl acetate. The extract was washed sequentially with 1N hydrochloric acid, water, 1M sodium bicarbonate, and water, dried over magnesium sulfate, filtered, and evaporated. Finally, it was dried in a vacuum oven. The amide-containing bio-based bisphenol 2a was obtained as a yellow solid in a 97% yield. 1 HNMR(400MHz,DMSO-d6)δ9.42(s,2H),7.97-7.95(t,2H),7.32-7.28(d,2H),7.08(s,2H),6.96-6.94(d,2H),6 .76-6.74(d,2H),6.43-6.39(d,2H),3.76(s,6H),3.15-3.10(m,4H),1.47-1.40(m,4H),1.32-1.26(m,2H).As attached Figure 2 shown.

[0049] Example 3a:

[0050] In a 100 mL reaction flask, ferulic acid (3.88 g, 20 mmol, 2 eq.) and triethylamine (1.4 mL, 10 mmol, 1 eq.) were dissolved in 20 mL of N,N-dimethylformamide at room temperature. The flask was then placed in an ice bath and 1,5-pentanediamine (1.17 mL, 10 mmol, 1 eq.) was slowly added dropwise. This was followed by the slow dropwise addition of a 20 mL solution of BOP (1.55 g, 10 mmol, 1 eq.) in dichloromethane. During the addition, floccules formed, and the color of the reaction solution gradually changed from yellow to reddish-brown. The reaction solution was placed in an ice bath at 0°C and stirred for 30 minutes, then brought to room temperature and stirred for 2 hours. Upon completion of the reaction, the solution returned to yellow, and the floccules disappeared. The dichloromethane was then removed under reduced pressure, and the solution was diluted with 150 mL of water. The product was extracted with ethyl acetate. The extract was washed sequentially with 1N hydrochloric acid, water, 1M sodium bicarbonate, and water, dried over magnesium sulfate, filtered, and evaporated. Finally, it was dried in a vacuum oven. The amide-containing bio-based bisphenol 2a was obtained as a yellow solid in a 96% yield. 1 HHNMR(400MHz,DMSO-d6)δ9.42(s,2H),7.97-7.95(t,2H),7.32-7.28(d,2H),7.08(s,2H),6.96-6.94(d,2H) ,6.76-6.74(d,2H),6.43-6.39(d,2H),3.76(s,6H),3.15-3.10(m,4H),1.47-1.40(m,4H),1.32-1.26(m,2H).

[0051] Example 4a:

[0052] In a 100 mL reaction flask, ferulic acid (3.88 g, 20 mmol, 2 eq.) and triethylamine (1.4 mL, 10 mmol, 1 eq.) were dissolved in 20 mL of N,N-dimethylformamide at room temperature. The flask was then placed in an ice bath and 1,5-pentanediamine (1.17 mL, 10 mmol, 1 eq.) was slowly added dropwise. This was followed by the slow dropwise addition of 20 mL of a dichloromethane solution of BOP (2.06 g, 10 mmol, 1 eq.). During the addition, floccules formed, and the color of the reaction solution gradually changed from yellow to reddish-brown. The reaction solution was placed in an ice bath at 0°C and stirred for 30 minutes, then brought to room temperature and stirred for 2 hours. Upon completion of the reaction, the solution returned to yellow, and the floccules disappeared. The dichloromethane was then removed under reduced pressure, and the solution was diluted with 150 mL of water. The product was extracted with ethyl acetate. The extract was washed sequentially with 1N hydrochloric acid, water, 1M sodium bicarbonate, and water, dried over magnesium sulfate, filtered, and evaporated. Finally, it was dried in a vacuum oven. The amide-containing bio-based bisphenol 2a was obtained as a yellow solid in a 94% yield.1 HHNMR(400MHz,DMSO-d6)δ9.42(s,2H),7.97-7.95(t,2H),7.32-7.28(d,2H),7.08(s,2H),6.96-6.94(d,2H) ,6.76-6.74(d,2H),6.43-6.39(d,2H),3.76(s,6H),3.15-3.10(m,4H),1.47-1.40(m,4H),1.32-1.26(m,2H).

[0053] Synthesis of Bio-based Epoxy Resin Monomers

[0054] Example 1b:

[0055] At room temperature, amide-containing bio-based bisphenol 1a (2.64 g, 6 mmol, 1.0 eq.) was dissolved in epichlorohydrin (12.71 mL, 159.6 mmol, 26.6 eq.) to form a pale yellow reaction solution. Potassium carbonate (0.071 g, 0.51 mmol, 0.085 eq.) was added as a catalyst, causing the reaction solution to change from pale yellow to yellow-brown. The reaction was allowed to proceed at 80°C for 2 h, until the reaction solution changed from yellow-brown to yellow. The reaction solution was cooled to room temperature, and a 40% wt. aqueous solution of sodium hydroxide (2.16 mL) was slowly added dropwise. The mixture was stirred at room temperature for 3 h, extracted with 25 mL of ethyl acetate three times, washed with saturated brine, dried, and the solvent removed under reduced pressure to obtain amide-containing bio-based epoxy resin monomer 1b as a white powder in a 90% yield. 1 HNMR(400MHz,Chloroform-d)δ8.03(s,2H),7.36-7.32(d,2H),7.16(s,2H),7.09-7.07(d,2H),6.99-6.97(d,2H),6.53-6.49(d,2H),4.38 -4.31(m,2H),4.08-3.96(m,2H),3.81(s,6H),3.47-3.42(m,2H),3.20-3.16(m,4H),2.85-2.83(t,2H),2.71-2.68(m,2H),1.47(s,4H).As attached Figure 3 shown.

[0056] Example 2b:

[0057] At room temperature, amide-containing bio-based bisphenol 2a (2.73 g, 6 mmol, 1.0 eq.) was dissolved in epichlorohydrin (12.71 mL, 159.6 mmol, 26.6 eq.) to form a pale yellow reaction solution. Potassium carbonate (0.071 g, 0.51 mmol, 0.085 eq.) was added as a catalyst, causing the reaction solution to change from pale yellow to yellow-brown. The reaction was allowed to proceed at 80°C for 2 h, until the reaction solution changed from yellow-brown to yellow. The reaction solution was cooled to room temperature, and a 40% wt. aqueous solution of sodium hydroxide (2.16 mL) was slowly added dropwise. The mixture was stirred at room temperature for 3 h, extracted with 25 mL of ethyl acetate three times, washed with saturated brine, dried, and the solvent removed under reduced pressure to obtain amide-containing bio-based epoxy resin monomer 2b as a white powder in a 92% yield. 1 H NMR(400MHz,Chloroform-d)δ8.04-8.01(t,2H),7.35-7.31(d,2H),7.16(s, 2H),7.08-7.06(d,2H),6.98-6.96(d,2H),6.54-6.50(d,2H),4.34-4.30(dd, 2H),4.17-4.01(m,2H),3.80(s,6H),3.33-3.32(m,2H),3.18-3.13(m,4H),2 .85-2.83(t,2H),2.70-2.67(m,2H),1.50-1.43(m,4H),1.35-1.29(m,2H).As attached Figure 4 shown.

[0058] Example 3b:

[0059] At room temperature, amide-containing bio-based bisphenol 1a (2.06 g, 6 mmol, 1.0 eq.) was dissolved in epichlorohydrin (12.71 mL, 159.6 mmol, 26.6 eq.) to form a pale yellow reaction solution. Tetrabutylammonium bromide (0.164 g, 0.51 mmol, 0.085 eq.) was added as a catalyst, causing the reaction solution to change from pale yellow to yellow-brown. The reaction was allowed to proceed at 80°C for 2 h, until the reaction solution changed from yellow-brown to yellow. The reaction solution was cooled to room temperature, and a 40% wt. aqueous solution of sodium hydroxide (2.16 mL) was slowly added dropwise. The mixture was stirred at room temperature for 3 h, extracted with 25 mL of ethyl acetate three times, washed with saturated brine, dried, and the solvent removed under reduced pressure to obtain amide-containing bio-based epoxy resin monomer 1b as a white powder in a 93% yield. 1H NMR(400MHz,Chloroform-d)δ8.03(s,2H),7.36-7.32(d,2H),7.16(s,2H),7.09-7.07(d,2H),6.99-6.97(d,2H),6.53-6.49(d,2H),4.3 8-4.31(m,2H),4.08-3.96(m,2H),3.81(s,6H),3.47-3.42(m,2H),3.20-3.16(m,4H),2.85-2.83(t,2H),2.71-2.68(m,2H),1.47(s,4H).

[0060] Example 4b:

[0061] At room temperature, amide-containing bio-based bisphenol 1a (2.06 g, 6 mmol, 1.0 eq.) was dissolved in epichlorohydrin (12.71 mL, 159.6 mmol, 26.6 eq.) to form a pale yellow reaction solution. Triethylamine (0.071 mL, 0.51 mmol, 0.085 eq.) was added as a catalyst, causing the reaction solution to change from pale yellow to yellow-brown. The reaction was allowed to proceed at 80°C for 2 h, until the reaction solution changed from yellow-brown to yellow. The reaction solution was cooled to room temperature, and a 40% wt. aqueous solution of sodium hydroxide (2.16 mL) was slowly added dropwise. The mixture was stirred at room temperature for 3 h, extracted three times with 25 mL of ethyl acetate, washed with saturated brine, dried, and the solvent removed under reduced pressure to obtain amide-containing bio-based epoxy resin monomer 1b as a white powder in 89% yield. 1 HNMR(400MHz,Chloroform-d)δ8.03(s,2H),7.36-7.32(d,2H),7.16(s,2H),7.09-7.07(d,2H),6.99-6.97(d,2H),6.53-6.49(d,2H),4.3 8-4.31(m,2H),4.08-3.96(m,2H),3.81(s,6H),3.47-3.42(m,2H),3.20-3.16(m,4H),2.85-2.83(t,2H),2.71-2.68(m,2H),1.47(s,4H).

[0062] Example 5b:

[0063] At room temperature, amide-containing bio-based bisphenol 1a (2.06 g, 6 mmol, 1.0 eq.) was dissolved in epichlorohydrin (12.71 mL, 159.6 mmol, 26.6 eq.) to form a pale yellow reaction solution. Dimethylaminopyridine (0.062 g, 0.51 mmol, 0.085 eq.) was added as a catalyst, causing the reaction solution to change from pale yellow to yellow-brown. The reaction was allowed to proceed at 80°C for 2 h, until the reaction solution changed from yellow-brown to yellow. The reaction solution was cooled to room temperature, and a 40% wt. aqueous solution of sodium hydroxide (2.16 mL) was slowly added dropwise. The mixture was stirred at room temperature for 3 h, extracted with 25 mL of ethyl acetate three times, washed with saturated brine, dried, and the solvent removed under reduced pressure to obtain amide-containing bio-based epoxy resin monomer 1b as a white powder in a 92% yield. 1 H NMR(400MHz,Chloroform-d)δ8.03(s,2H),7.36-7.32(d,2H),7.16(s,2H),7.09-7.07(d,2H),6.99-6.97(d,2H),6.53-6.49(d,2H),4.3 8-4.31(m,2H),4.08-3.96(m,2H),3.81(s,6H),3.47-3.42(m,2H),3.20-3.16(m,4H),2.85-2.83(t,2H),2.71-2.68(m,2H),1.47(s,4H).

[0064] Example 6b:

[0065] by 1 The epoxy value of the bio-based epoxy resin monomer was determined by the HNMR internal standard method. The specific method is to determine the absolute epoxy value of the bio-based epoxy resin monomer by adding the internal standard tetrachloroethane. First, weigh the epoxy resin monomer Xg (X=0.0225) obtained in Example 1b and weigh the internal standard tetrachloroethane Yg (Y=0.0208). After combining, add 0.6mL of deuterated chloroform to dissolve it. The results are shown in the attached figure. Figure 5 The characteristic peak of tetrachloroethane is at 6.0 ppm, and the characteristic peak of epoxy is at 3.3 ppm. There are three peaks. According to the characteristic peaks of tetrachloroethane and one of the epoxy peaks, the peak area ratio is Z (Z = 3.81). Then the epoxy value of X grams of bio-based epoxy resin monomer can be measured by the following formula:

[0066]

[0067] According to the NMR internal standard method, the formula is as follows, where Y is the mass of the added internal standard tetrachloroethane, and Z is the ratio of the peak area of ​​the tetrachloroethane characteristic peak to the epoxy characteristic peak in the NMR.

[0068] It was determined that 0.0225 g of the bio-based epoxy resin monomer 1b (Example 1b) contained 0.064 mmol of epoxy, and thus 0.7 g of the bio-based epoxy resin monomer contained 1.0 mmol of epoxy.

[0069] According to the purchase information label (brand name COROA), 0.537g of Priaminee 1074 contains 1mmol of amine; 0.376g of Priamine TM 1071 contains 1 mmol of amine; 0.858 g of dimeric Priamine TM 1075 contains 1 mmol of amine.

[0070] Preparation of bio-based epoxy resin

[0071] Example 1c:

[0072] 140 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 1b and Priamine TM 53.7 g (about 0.1 mol) of 1074 (produced by Croda, with a biochar content of 100%) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix evenly. During this period, the reduced pressure was used to remove gas and chloroform. The sample was transferred to a mold using a glass dropper and cured in an oven at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 1c#.

[0073] Example 2c

[0074] 1400 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 1b and Priamine TM 37.6 g (about 0.1 mol) of 1071 (produced by Croda, with a biochar content of 100%) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix evenly. During this period, the reduced pressure was used to remove gas and chloroform. The mixture was transferred to a mold using a glass dropper and placed in an oven for curing at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 2c#.

[0075] Example 3c

[0076] 140 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 1b and Priamine TM85.76 g (about 0.1 mol) of 1075 (produced by Croda, with a biochar content of 100%) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 3 minutes to mix evenly. During this period, the reduced pressure was used to remove gas and chloroform. The sample was transferred to a mold using a glass dropper and placed in an oven for curing at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 3c#.

[0077] Example 4c

[0078] 140 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 1b and 10.21 g (about 0.1 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterials Co., Ltd., with a biocarbon content of 100%) were placed in a three-necked reaction flask, dissolved in chloroform, heated at 80°C and stirred in the reaction flask for 2 minutes to mix evenly. During the process, the gas and chloroform were removed by reducing the pressure, and the mixture was transferred to a mold using a glass dropper. After curing in an oven at 80°C for 4 hours, the temperature was then raised to 120°C and cured by blast heating for 20 hours to obtain an epoxy resin sample numbered 4c#.

[0079] Example 5c

[0080] 130 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 2b (according to the epoxy value measurement method used in Example 6b, the epoxy value of the epoxy resin monomer 2b was measured to be 0.65 g / mmol) and 10.2 g (about 0.1 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterials Co., Ltd., with a biocarbon content of 100%) were placed in a three-necked reaction flask, dissolved in chloroform, heated at 80°C and stirred in the reaction flask for 2 minutes to mix evenly, during which time the gas and chloroform were removed by reduced pressure. The mixture was transferred to a mold using a glass dropper, placed in an oven at 80°C for curing for 4 hours, then heated to 120°C and cured by blower heating for 20 hours to obtain an epoxy resin sample numbered 5c#.

[0081] Example 6c

[0082] 130 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 2b, 5.1 g (about 0.05 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterial Co., Ltd.), and Priamine TM 42.88 g (approximately 0.05 mol) of 1075 (produced by Croda) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix uniformly. During this period, the chloroform and the mixture were removed by decompression. The mixture was transferred to a mold using a glass dropper and cured in an oven at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 6c#.

[0083] Example 7c

[0084] 130 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 2b, 5.1 g (about 0.05 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterial Co., Ltd., with a biocarbon content of 100%) and Priamine TM 18.8 g (about 0.05 mol) of 1071 (produced by Croda) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix evenly. During this period, the gas and chloroform were removed by reduced pressure. The product was transferred to a mold using a glass dropper and cured in an oven at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 7c#.

[0085] Example 8c

[0086] 130 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 2b, 5.1 g (about 0.05 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterial Co., Ltd., with a biocarbon content of 100%) and Priamine TM 26.8 g (about 0.05 mol) of 1074 (produced by Croda) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix evenly. During this period, the gas and chloroform were removed by reduced pressure. The product was transferred to a mold using a glass dropper and cured in an oven at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 8c#.

[0087] Example 9c

[0088] 140 g (about 0.2 mol) of the bio-based epoxy resin monomer prepared in Example 1b, 5.1 g (about 0.05 mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterial Co., Ltd., with a biocarbon content of 100%) and Priamine TM 26.8 g (approximately 0.05 mol) of 1074 (produced by Croda) was placed in a three-necked reaction flask, dissolved in chloroform, and heated at 80°C with stirring in the reaction flask for 2 minutes to mix uniformly. During this period, the chloroform and the mixture were removed by decompression. The mixture was transferred to a mold using a glass dropper and cured in an oven at 80°C for 4 hours. The temperature was then raised to 120°C and cured with forced air heating for 20 hours to obtain an epoxy resin sample, numbered 9c#.

[0089] Example 10c

[0090] The traditional preparation method of bisphenol A epoxy resin (control resin sample) is as follows: 68g (about 0.2mol) of bisphenol A glycidyl ether (purchased from Shanghai San Chemical Co., Ltd.), 5.1g (about 0.05mol) of 1,5-pentanediamine (produced by Kaisai (Jinxiang) Biomaterials Co., Ltd., with a biocarbon content of 100%) and 26.8g (about 0.05mol) of diamine PriamineTM1071 (produced by Croda) are placed in a three-necked reaction bottle, dissolved in chloroform, heated at 80°C and stirred in the reaction bottle for 2 minutes to mix evenly, during which the gas and chloroform are removed by decompression, and the epoxy resin sample is transferred to a mold using a glass dropper. After being cured in an oven at 80°C for 4h, the temperature is then raised to 120°C and cured by blower heating for 20h to obtain an epoxy resin sample numbered 10c#.

[0091] Example 11c

[0092] Application of epoxy resin adhesive. Dissolve 70 g (0.1 mol) of the bio-based epoxy resin monomer prepared in Example 1b in chloroform and stir at 80°C for 2 minutes. Then add 10.21 g (0.1 mol) of 1,5-pentanediamine. At this point (epoxy:amine = 1:1), continue vacuum degassing and chloroform at 80°C until a homogeneous phase is formed. Immediately apply the adhesive to a metal block while hot. After evenly applying, adhere the metal block to another metal block and press to fit. Place the adhesive in an 80°C oven to cure for 4 hours, then place it in a 120°C oven to cure for 20 hours. Remove the metal blocks and cool them to room temperature to obtain fully bonded metal blocks.

[0093] Epoxy resin performance test

[0094] Mechanical property analysis: Mechanical property tests were conducted on a CMT4000 universal testing machine. Dumbbell-shaped standard specimens were prepared according to ASTM D638-08 for testing, with a crosshead speed of 2 mm / min. Impact tests were conducted on a JJ-20 memory impact tester, using specimens prepared according to ASTM D7264 at a crosshead speed of 1 mm / min. Thermal property analysis was conducted on a Discovery 250 instrument. Under a nitrogen atmosphere, the heating rate was 10°C / min.

[0095] Table 1 Comparison between bio-based epoxy resin and traditional bisphenol A epoxy resin (10c#)

[0096]

[0097] Table 1 shows the performance of the epoxy resin obtained according to the embodiment of the present invention. It can be seen from Table 1 that the variety of curing agent has a greater impact on the mechanical properties of the final product. The epoxy resin obtained by only adopting the diamine curing agent has a larger impact strength and a larger elongation at break, indicating that the toughness of the epoxy resin is better, while the epoxy resin obtained by only adopting the 1,5-pentanediamine curing agent has a larger tensile strength, indicating that the strength of the epoxy resin is larger. The epoxy resin obtained by adopting the mixed curing agent combines the advantages of the two and has the best performance. And as can be seen from Table 1, compared with traditional bisphenol A type epoxy resin, the epoxy resin of the present invention has the advantages of being green and environmentally friendly, low raw material price, good mechanical properties, high glass transition temperature, and large hardness.

[0098] The present invention provides a fully bio-based epoxy resin and a method for preparing the same. Numerous methods and approaches exist for implementing this technical solution. The foregoing merely represents a preferred embodiment of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are considered within the scope of protection of the present invention. Any components not specified in this embodiment may be implemented using existing technologies.

Claims

1. A method for preparing bio-based bisphenol, characterized in that: The steps are as follows: The n is selected from 2 or 3; Ferulic acid and bio-based diamine undergo an amidation reaction in the presence of a condensing agent to obtain a bio-based bisphenol as shown in formula (II); The condensing agent is benzotriazole-1-bis(trimethylamino)phosphine-hexafluorophosphate, dicyclohexylcarbodiimide or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

2. The preparation method according to claim 1, characterized in that The molar ratio of the ferulic acid to the bio-based diamine is 2:1 to 2.5:

1.

3. A bio-based epoxy resin monomer as shown in formula (I), characterized in that: The n is selected from 2 or 3 The bio-based epoxy resin monomer shown in formula (I) is prepared by using the bio-based bisphenol shown in formula (II).

4. A method for preparing a bio-based epoxy resin monomer as represented by formula (I) according to claim 3, characterized in that: The bio-based bisphenol represented by formula (II) is reacted with epichlorohydrin under the catalysis of a base to generate a bio-based epoxy compound represented by formula (I); The base is potassium carbonate, dimethylaminopyridine, tetrabutylammonium bromide and triethylamine.

5. The preparation method according to claim 4, characterized in that The molar ratio of the bio-based bisphenol represented by formula (II) to epichlorohydrin is 1:16 to 1:

26.

6. A method for preparing a bio-based epoxy resin, characterized in that: The bio-based epoxy resin monomer is mixed with a curing agent to obtain a bio-based epoxy resin, wherein the curing agent is 1,5-pentanediamine, Primin e TM 1074、Priamine TM 1075、Priamine TM One or a mixture of 1071.

7. Use of the bio-based epoxy resin monomer according to claim 3 and the bio-based epoxy resin monomer prepared according to claim 4 or 5 in an adhesive.

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