阅读说明：本技术 一种腰果酸环氧树脂及其制备方法 (Anacardic acid epoxy resin and preparation method thereof ) 是由 陈健 孔振武 吴国民 刘贵锋 霍淑平 于 2020-07-31 设计创作，主要内容包括：本发明公开了一种腰果酸环氧树脂及其制备方法。以腰果酸与环氧氯丙烷在催化剂作用下开环反应,然后在碱存在下闭环反应,制备得到腰果酸环氧树脂-I(EACA-Ⅰ)。腰果酸环氧树脂-I(EACA-Ⅰ)再与过氧化物反应得到腰果酸环氧树脂-II(EACA-Ⅱ)。本发明制备的腰果酸环氧树脂是一种生物基环氧树脂,具有高环氧值、低黏度等特点,与酸酐或胺类固化剂的固化物具有优良的机械性能和热稳定性能,可应用于复合材料、胶黏剂和涂料等领域。(The invention discloses anacardic acid epoxy resin and a preparation method thereof. The preparation method comprises the steps of carrying out ring opening reaction on anacardic acid and epoxy chloropropane under the action of a catalyst, and carrying out ring closing reaction in the presence of alkali to prepare anacardic acid epoxy resin-I (EACA-I). Reacting anacardic acid epoxy resin-I (EACA-I) with peroxide to obtain anacardic acid epoxy resin-II (EACA-II). The anacardic acid epoxy resin prepared by the invention is a bio-based epoxy resin, has the characteristics of high epoxy value, low viscosity and the like, has excellent mechanical property and thermal stability with a condensate of an anhydride or amine curing agent, and can be applied to the fields of composite materials, adhesives, coatings and the like.)

1. A kind of anacardic acid epoxy resin is characterized in that: the chemical structural formula is as follows:

2. the preparation method of the anacardic acid epoxy resin of the class of the claim 1, characterized in that anacardic acid and epoxy chloropropane are subjected to ring opening reaction under the action of a catalyst and then subjected to ring closing reaction in the presence of alkali to prepare anacardic acid epoxy resin-I, and the anacardic acid epoxy resin-I is further subjected to reaction with peroxide to prepare anacardic acid epoxy resin-II; the chemical reaction formula of the preparation process is as follows:

3. the method for preparing a type of cashew epoxy resin as claimed in claim 2, wherein the method is carried out by the steps of:

the first step is as follows: preparation of anacardic acid epoxy resin-I (EACA-I): reacting the anacardic acid and epoxy chloropropane at 70-120 ℃ for 2-10 h under the action of a catalyst, cooling a reaction system to 40-80 ℃ after the reaction is finished, adding a certain amount of alkali in batches, keeping the temperature for reaction for 2-8 h, washing the reaction system to be neutral after the reaction is finished, and distilling an organic phase under reduced pressure to obtain EACA-I;

the second step is that: dissolving EACA-I in a certain amount of solvent, adding peroxide in batches in an ice water bath at 10-15 ℃, reacting for 10-20 min under heat preservation after adding, slowly heating to 20-50 ℃ for reacting for 2-4 h, cooling to room temperature after reaction, performing suction filtration, washing the filtrate to neutrality by saturated sodium sulfite, saturated sodium bicarbonate and water in sequence, and performing reduced pressure distillation on the organic phase to obtain anacardic acid epoxy resin-II (EACA-II).

4. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the catalyst in the first step is one or more selected from benzyltriethylammonium chloride, benzyltrimethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide and hexamethynyltetraammonium, and the amount of the catalyst is 0.1-5% by mass of cardanic acid.

5. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the amount of epichlorohydrin used in the first step is 2-30 times of the amount of anacardic acid.

6. The method for preparing anacardic acid-like epoxy resin as claimed in claim 3, wherein the alkali in the first step is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide, and the ratio of the alkali to anacardic acid is 2-2.5: 1.

7. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the optimal preparation reaction conditions of anacardic acid epoxy resin-I are as follows: the dosage of the catalyst is 2.0% of the mass of the anacardic acid, the ring-opening reaction temperature is 100 ℃, the ring-opening reaction time is 6 hours, the mass ratio of the alkali to the anacardic acid is 2.1:1, the ring-closing reaction temperature is 60 ℃, and the ring-closing reaction time is 4 hours. Under the reaction condition, the obtained cardanic acid epoxy resin-I has an epoxy value of 0.37mol/100 g.

8. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the peroxide in the second step is one or more selected from m-chloroperoxybenzoic acid, peracetic acid, dimethyl ketone peroxide and hydrogen peroxide, and the amount of the peroxide is 1 to 3 times of the amount of anacardic acid epoxy resin-I.

9. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the solvent in the second step is one or more selected from dichloromethane, methanol, toluene and chloroform, and the amount of the solvent is 5-20 times of the mass of anacardic acid epoxy resin-I.

10. The method for preparing anacardic acid epoxy resin as claimed in claim 3, wherein the optimal preparation reaction conditions of anacardic acid epoxy resin-II are as follows: dissolving EACA-I in dichloromethane with the mass 5 times that of the mixture, adding m-chloroperoxybenzoic acid with the mass 2.1 times that of EACA-I in batches in an ice-water bath at the temperature of 10-15 ℃, keeping the temperature for reaction for 10-20 min after the addition is finished, and slowly heating to 40 ℃ for reaction for 2 h. Cooling to room temperature after the reaction is finished, carrying out suction filtration, washing the filtrate to be neutral by using saturated sodium sulfite, saturated sodium bicarbonate and water in sequence, and carrying out reduced pressure distillation on an organic phase to obtain the anacardic acid epoxy resin-II (EACA-II), wherein the epoxy value is 0.62mol/100 g.

Technical Field

The invention relates to a cardanic acid epoxy resin and a preparation method thereof, in particular to a method for preparing epoxy resin by reacting cardanic acid with epoxy chloropropane, alkali and peroxide, and belongs to the field of bio-based high polymer materials.

Background

Anacardic acid is the main component of cashew nut shell liquid which is a byproduct in the cashew industry. At present, related research reports on the medical fields of antibiosis, rheumatoid arthritis resistance, tumor resistance and the like are provided for anacardic acid, but the research and the application of anacardic acid in high polymer materials are few. Since the extraction of the cashew nut shell liquid generally adopts high-temperature squeezing or hot oil extraction, the main component of the industrial cashew nut shell liquid is a mixture of cardanol and cardol obtained by decarboxylation of cardanic acid. Cardanol can completely or partially replace petroleum-based phenolic compounds to be applied to preparation of epoxy resin, phenolic resin, photocuring monomers and the like, and a plurality of documents are reported and industrially applied. The common epoxy resin is cardanol glycidyl ether and epoxy resin prepared by side chain epoxidation. The cardanol glycidyl ether reported in patent CN104710388A has high plasticizing efficiency, and can impart good thermal stability and mechanical properties to a resin product, but the cardanol glycidyl ether is a monofunctional epoxide, and cannot be cured and molded with a curing agent alone, and is generally used as an epoxy active diluent or a plasticizer. In addition, cashew phenol formaldehyde epoxy resin is also reported, and the cashew phenol formaldehyde epoxy resin reported in patent CN103012743A is a multifunctional epoxy resin containing both benzene ring and alkyl long chain, has both high thermal stability of phenol formaldehyde resin and high reactivity of epoxy resin, has excellent curing performance, but uses formaldehyde in the preparation process, thus having potential harm to environment and biological health.

The anacardic acid molecular structure not only contains phenolic hydroxyl and carboxyl, but also contains functional groups such as side chain unsaturated double bonds, and the like, and the multifunctional bio-based epoxy resin can be synthesized by utilizing the molecular structure characteristics of the anacardic acid, and the report of documents is not found. The epoxy resin with bifunctionality is obtained after epoxidation reaction of the anacardic acid and epoxy chloropropane, the functionality of unsaturated double bonds of side chains is further improved after epoxidation, and a cured product of the epoxy resin and anhydride or amine curing agent has excellent mechanical property and heat resistance, and can be applied to the fields of high-performance special coatings, adhesives, electronic and electrical materials, composite materials and the like.

Disclosure of Invention

The anacardic acid epoxy resin and the preparation method thereof provided by the invention have the advantages that the prepared epoxy resin has a higher epoxy value and a lower viscosity, and has a higher crosslinking density after being cured with a curing agent, so that the anacardic acid epoxy resin has good mechanical properties and heat resistance.

A kind of anacardic acid epoxy resin, the chemical structural formula is:

according to the preparation method of the anacardic acid epoxy resin, anacardic acid and epoxy chloropropane are subjected to ring opening reaction under the action of a catalyst, then ring closing reaction is carried out in the presence of alkali, anacardic acid epoxy resin-I is prepared, and anacardic acid epoxy resin-I is further reacted with peroxide to prepare anacardic acid epoxy resin-II; the chemical reaction formula of the preparation process is as follows:

the method for preparing the anacardic acid epoxy resin is realized by the following steps:

the first step is as follows: preparation of anacardic acid epoxy resin-I (EACA-I): reacting the anacardic acid and epoxy chloropropane at 70-120 ℃ for 2-10 h under the action of a catalyst, cooling a reaction system to 40-80 ℃ after the reaction is finished, adding a certain amount of alkali in batches, keeping the temperature for reaction for 2-8 h, washing the reaction system to be neutral after the reaction is finished, and distilling an organic phase under reduced pressure to obtain EACA-I;

the second step is that: dissolving EACA-I in a certain amount of solvent, adding peroxide in batches in an ice water bath at 10-15 ℃, reacting for 10-20 min under heat preservation after adding, slowly heating to 20-50 ℃ for reacting for 2-4 h, cooling to room temperature after reaction, performing suction filtration, washing the filtrate to neutrality by saturated sodium sulfite, saturated sodium bicarbonate and water in sequence, and performing reduced pressure distillation on the organic phase to obtain anacardic acid epoxy resin-II (EACA-II).

The catalyst in the first step is any one or more of benzyltriethylammonium chloride, benzyltrimethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide and hexamethynyltetraammonium, and the dosage of the catalyst is 0.1-5% of the mass of the cardanic acid.

The using amount of the epichlorohydrin in the first step is 2-30 times of the amount of the anacardic acid substance.

In the first step, the alkali is any one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide, and the mass ratio of the alkali to the anacardic acid is 2-2.5: 1.

The optimal preparation reaction conditions of the anacardic acid epoxy resin-I are as follows: the dosage of the catalyst is 2.0% of the mass of the anacardic acid, the ring-opening reaction temperature is 100 ℃, the ring-opening reaction time is 6 hours, the mass ratio of the alkali to the anacardic acid is 2.1:1, the ring-closing reaction temperature is 60 ℃, and the ring-closing reaction time is 4 hours. Under the reaction condition, the obtained cardanic acid epoxy resin-I has an epoxy value of 0.37mol/100 g.

In the second step, the peroxide is any one or more of m-chloroperoxybenzoic acid, peracetic acid, dimethyl ketone peroxide and hydrogen peroxide, and the using amount of the peroxide is 1-3 times of that of the anacardic acid epoxy resin-I substance.

In the second step, the solvent is any one or more of dichloromethane, methanol, toluene and trichloromethane, and the dosage of the solvent is 5-20 times of the mass of the anacardic acid epoxy resin-I.

The optimal preparation reaction conditions of the anacardic acid epoxy resin-II are as follows: dissolving EACA-I in dichloromethane with the mass 5 times that of the mixture, adding m-chloroperoxybenzoic acid with the mass 2.1 times that of EACA-I in batches in an ice-water bath at the temperature of 10-15 ℃, keeping the temperature for reaction for 10-20 min after the addition is finished, and slowly heating to 40 ℃ for reaction for 2 h. Cooling to room temperature after the reaction is finished, carrying out suction filtration, washing the filtrate to be neutral by using saturated sodium sulfite, saturated sodium bicarbonate and water in sequence, and carrying out reduced pressure distillation on an organic phase to obtain the anacardic acid epoxy resin-II (EACA-II), wherein the epoxy value is 0.62mol/100 g.

Has the advantages that:

1. the anacardic acid epoxy resin synthesized by anacardic acid instead of bisphenol A is degradable bio-based epoxy resin and has the advantages of high epoxy value, low viscosity, environmental compatibility and the like.

2. A cured product of the anacardic acid epoxy resin and the acid anhydride or amine curing agent has excellent mechanical property and heat resistance, and can be applied to the fields of high-performance coatings, epoxy adhesives, composite materials and the like.

Drawings

FIG. 1 is a graph of infrared spectra (FT-IR) of anacardic acid and anacardic acid epoxy resins. ACA is anacardic acid; EACA-I: anacardic acid epoxy resin-I; EACA-II: anacardic acid epoxy resin-II.

FIG. 2 of anacardic acid and anacardic acid epoxy resin¹HNMR spectrogram. ACA is anacardic acid; EACA-I: anacardic acid epoxy resin-I; EACA-II: anacardic acid epoxy resin-II.

FIG. 3 of anacardic acid and anacardic acid epoxy resin¹³CNMR spectrogram. ACA is anacardic acid; EACA-I: anacardic acid epoxy resin-I; EACA-II: anacardic acid epoxy resin-II.

FIG. 4 is a Differential Scanning Calorimetry (DSC) analysis chart of the curing reaction process of anacardic acid epoxy resin, methylhexahydrophthalic anhydride, and isophorone diamine. EACA-I/MeHHPA; EACA-II/MeHHPA; EACA-I/IPDA; EACA-II/IPDA.

FIG. 5 is a thermogravimetric analysis (TGA) chart of a cured product of an anacardic acid epoxy resin, methylhexahydrophthalic anhydride, and isophorone diamine. Wherein a is TG diagram and b is DTG diagram. EACA-I/MeHHPA; EACA-II/MeHHPA; EACA-I/IPDA; EACA-II/IPDA.

1730cm in the infrared spectrum of anacardic acid epoxy resin (FIG. 1)^-1、1265cm^-1And 1112cm^-1Is treated as a benzoate absorption peak at 908cm^-1And 840cm^-1Is an epoxy group-characteristic absorption peak.

Anacardic acid epoxy resin¹In the HNMR spectrum (FIG. 2), EACA-I of 2.27, 2.66, 3.10-3.12, 3.26, 3.40-3.46, 3.75, 3.87, 4.05, 4.21-4.27 and 4.55-4.60 corresponds to hydrogen on carbon of glycidyl ester and glycidyl ether; EACA-II is 1.40, 1.61-1.67, 2.87 and 2.97 corresponding to hydrogen on carbon after unsaturated double bond epoxidation of anacardic acid side chain.

Of anacardic acid epoxy resins¹³CNMR spectrum (FIG. 3), EACA-I: peaks at 43.51-43.92, 48.95-50.39, 62.52, 64.69, 68.74-69.37 and 167.09 correspond to the carbons on the glycidyl ester and ether; EACA-II: 53.50-56.03 corresponds to carbon after epoxidation of unsaturated double bonds of side chains.

Detailed Description

A anacardic acid epoxy resin and a preparation method thereof, the anacardic acid epoxy resin prepared has a chemical structural formula as follows:

the method is realized by the following steps:

the first step is as follows: the cashew nut acid and the epoxy chloropropane are subjected to ring-opening reaction for 2 to 10 hours at 70 to 120 ℃ under the action of a catalyst. Cooling the reaction system to 40-80 ℃, adding a certain amount of alkali in batches, and carrying out ring-closure reaction for 2-8 h. And (3) after the reaction is finished, washing the mixture to be neutral, and distilling the organic phase under reduced pressure to obtain the anacardic acid epoxy resin-I.

The second step is that: dissolving EACA-I in a certain amount of solvent, adding peroxide in batches in an ice-water bath at 10-15 ℃, reacting for 10-20 min after the addition is finished, and slowly heating to 20-50 ℃ for reacting for 2-4 h. Cooling to room temperature after the reaction is finished, carrying out suction filtration, washing the filtrate to be neutral by using saturated sodium sulfite, saturated sodium bicarbonate and water in sequence, and carrying out reduced pressure distillation on an organic phase to obtain the anacardic acid epoxy resin-II (EACA-II).

The chemical reaction formula of the preparation process is as follows:

the catalyst in the first step is any one or more of benzyltriethylammonium chloride, benzyltrimethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide and hexamethynyltetraammonium, and the dosage of the catalyst is 0.1-5% of the mass of the cardanic acid.

The dosage of the epichlorohydrin is 2-30 times of the dosage of the anacardic acid substance.

The alkali is any one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and barium hydroxide, the mass ratio of the alkali to the anacardic acid is 2: 1-2.5: 1, and the mass ratio of the alkali to the anacardic acid is 2.1:1 optimally.

The ring-opening reaction temperature is 70-120 ℃, and the ring-opening reaction time is 2-10 h. The ring-opening reaction temperature is optimally 100 ℃, and the ring-opening reaction time is optimally 6 h.

The ring-closing reaction temperature is 40-80 ℃, and the ring-closing reaction time is 2-8 h. The optimal ring-closing reaction temperature is 60 ℃, and the optimal ring-closing reaction time is 4 h.

In the second step, the peroxide is any one or more of m-chloroperoxybenzoic acid, peracetic acid, dimethyl ketone peroxide and hydrogen peroxide, and the using amount of the peroxide is 1-3 times of that of the anacardic acid epoxy resin-I substance.

The solvent is any one or more of dichloromethane, methanol, toluene and trichloromethane, and the amount of the solvent is 5-20 times of the mass of the anacardic acid epoxy resin-I.

The reaction temperature is 20-50 ℃, and the reaction time is 2-4 h.

The optimal preparation reaction conditions of the anacardic acid epoxy resin-II are as follows: dissolving EACA-I in 5 times of dichloromethane by mass, adding 2.1 times of m-chloroperoxybenzoic acid by EACA-I in batches in ice-water bath at 10-15 ℃, and reacting for 2h at 40 ℃.