A method for modifying dicyclopentadiene phenol resin using flavonoid biomass

Abstract

The present invention belongs to the field of phenolic resin synthesis, and specifically relates to a method for modifying dicyclopentadiene phenol resin with flavonoid biomass. The present invention uses a heat-resistant strongly acidic cation exchange resin as a catalyst and partially replaces phenol with daidzein to prepare the dicyclopentadiene phenol resin. The daidzein can effectively replace phenol, and the addition of daidzein can also improve the performance of the resin. The addition reaction of the benzopyran ring is conducive to the formation of cross-linking density. The appropriate amount of daidzein substitution can increase the degree of cross-linking. Finally, the resin synthesized by modifying the daidzein has good corrosion resistance, friction resistance, water absorption resistance, and thermal stability.

Description

Technical Field

[0001] The invention belongs to the field of phenolic resins, and particularly relates to a method for modifying dicyclopentadiene phenol resin with flavonoid biomass, specifically a method for modifying the dicyclopentadiene phenol resin by using a temperature-resistant strongly acidic cation exchange resin as a catalyst and replacing part of phenol with daidzein. Background Art

[0002] Soybean flavonoids are primarily isoflavone compounds, natural polyphenol monomers extracted from leguminous plants. They are low-toxic and environmentally friendly, with a phenolic hydroxyl group similar to phenol in structure. Two benzene rings are interconnected by multiple carbon atoms, resulting in a highly rigid structure. Among potential biomass alternatives, they are excellent renewable resources with more reactive sites. As a biomass alternative to fossil resources, daidzein is also being developed into biosynthetic resins, demonstrating excellent performance.

[0003] Dicyclopentadiene phenol resin is an important raw material for electronic packaging materials. Due to the phenolic hydroxyl groups, benzene rings, five-membered rings and six-membered rings it contains, the resin has excellent flame retardancy, water resistance, chemical resistance and electrical insulation properties. It can be used in the production of adhesives, battery application-related materials, glass fiber reinforced composite matrix resins, electronic packaging, and other emerging fields.

[0004] While dicyclopentadiene phenol resin offers numerous advantages, it still falls short of meeting the demand for environmentally friendly, low-toxic applications. For example, the non-renewable and toxic nature of the raw materials used in its synthesis, along with the corrosive and non-recyclable nature of the traditional acid catalysts (such as methanesulfonic acid) required for the reaction, make it incompatible with green production requirements. Summary of the Invention

[0005] Based on the technical problems pointed out in the background technology section, the present invention uses a heat-resistant strong acidic cation exchange resin as a catalyst and partially replaces phenol with daidzein to prepare a dicyclopentadiene phenol resin. Daidzein can effectively replace phenol. At the same time, the addition of daidzein can also improve the performance of the resin. The addition reaction of the benzopyran ring is conducive to the formation of cross-linking density. The appropriate daidzein replacement amount can increase the cross-linking degree. Finally, the resin modified with daidzein has good corrosion resistance, friction resistance, water absorption resistance, and thermal stability.

[0006] To achieve the above objectives, the present invention provides a method for modifying dicyclopentadiene phenol resin with flavonoid biomass, wherein the daidzein-modified dicyclopentadiene phenol resin is synthesized by catalysis using a temperature-resistant strongly acidic cation exchange resin. The specific steps are as follows:

[0007] (1) Add phenol and daidzein to a four-necked flask equipped with a stirrer, reflux condenser, and thermometer. Stir and preheat the mixture under nitrogen protection. Since the reaction is a two-phase reaction, an appropriate amount of phase transfer catalyst is required. A heat-resistant, strongly acidic cation exchange resin is also added. Adjust the temperature of the reactor to 80°C to 85°C and add dicyclopentadiene dropwise under stirring. After the addition is complete, heat the mixture and allow to react. After the reaction is complete, cool the mixture to obtain the reaction product.

[0008] (2) Sodium hydroxide is added dropwise until neutral, and the resulting product is subjected to heating and reduced pressure dephenolization to obtain daidzein-modified dicyclopentadiene phenol resin.

[0009] The mass ratio of the total mass of daidzein and phenol to dicyclopentadiene is 3:1-1.1; preferably, the mass ratio of the total mass of daidzein and phenol to dicyclopentadiene is 3:1.05; and daidzein accounts for 20%-25% of the total mass of daidzein and phenol.

[0010] This heat-resistant, strongly acidic cation exchange resin is synthesized from styrene and divinylbenzene through four steps: polymerization, physical structure stabilization, halogenation, and sulfonation. Compared to conventional strongly acidic cation exchange resins, the sulfonic acid group is located ortho to the benzene ring, improving thermal stability. The dosage is 0.5% to 3% of the total reactants; preferably, 2% to 3% of the total reactants.

[0011] The amount of the phase transfer catalyst used is 0.9% to 1% of the reaction material; the phase transfer catalyst is hexadecyltrimethylammonium bromide.

[0012] The preheating temperature is 60~65℃, and after adding the catalyst, the mixture is kept warm and stirred for 0.5h; the reaction system is heated to 80~85℃, and dicyclopentadiene is added dropwise using a constant pressure dropping funnel under stirring for 0.5h. After the addition is completed, the mixture is kept warm for 1h.

[0013] The reaction temperature after the dropwise addition of dicyclopentadiene is 100-140° C., and the reaction time is 3-7 hours; preferably, the reaction temperature is 110-120° C., and the reaction time is 5-6 hours.

[0014] The vacuum degree of reduced pressure dephenolization is -0.095MPa, the temperature is 180-190℃, and the time is 2h.

[0015] The present invention is a catalyst with a heat-resistant strongly acidic cation exchange resin. The catalyst is not only free of wastewater during the reaction process, but also environmentally friendly and can be reused. Catalysis daidzein replaces the dicyclopentadiene phenol resin made with part of the phenol. Daidzein can effectively replace phenol to catalyze the alkylation reaction of phenol and dicyclopentadiene. It can be removed without washing and is simple to operate. Adding daidzein simultaneously can also improve the performance of the resin. The suitable daidzein substitution amount can improve the cross-linking degree. The resin synthesized by modifying daidzein at last has good heat resistance, corrosion resistance, friction resistance, water absorption resistance and thermal stability. The whole reaction process is relatively simple, environmentally friendly and has good economic benefits.

[0016] The specific advantages of the present invention are as follows:

[0017] 1. The reaction raw materials are extensive, with daidzein as the raw material, which is non-toxic and structurally similar to phenol. They are excellent renewable resources.

[0018] 2. The two benzene rings have multiple carbon atoms connected to each other, which have highly rigid structural functions and more reaction sites.

[0019] 3. Using heat-resistant strong acid cation exchange resin as catalyst, it can be reused and is more environmentally friendly.

[0020] 4. The reaction conditions are relatively mild and the operation is simple.

[0021] 5. There is no wastewater discharge in the synthesis process, which is an environmentally friendly process route. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples, but this should not be construed as limiting the present invention.

[0023] Unless otherwise specified, the experimental methods or test methods described in the following examples are all conventional methods; the reagents and materials described are all obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0024] The structural formula of the strongly acidic cation exchange resin involved in the present invention is:

[0025] , X is a halogen, and n is an integer greater than or equal to 1.

[0026] A heat-resistant, strongly acidic cation exchange resin is synthesized using styrene and divinylbenzene as raw materials through four steps: polymerization, physical structure stabilization, halogenation, and sulfonation. Specifically, distilled water and methylene blue were added to a flask, along with 5% polyvinyl alcohol. The mixture was stirred and heated to 40°C. A mixture of 20g styrene and 5g divinylbenzene containing 0.25g benzoyl peroxide was added, and the temperature was continued to rise to 70°C. The mixture was kept at 70°C for 1 hour, then raised to 85-87°C and allowed to react for 1 hour. Once the pellets were solidified, the temperature was raised to 95°C and the reaction continued for 2 hours. After 2 hours, stirring was stopped and heating was continued for 2-3 hours. The pellets were then filtered out, washed twice with hot water, and then twice with distilled water. The washed pellets were then dried in an oven at 80°C for 2 hours to obtain the product pellets. The resulting pellets are swollen with dichloroethane for 2 hours. Bromine is added dropwise with stirring under the catalysis of anhydrous ferric chloride below 20°C. The pellets are reacted at 0°C for 10 hours, filtered, and washed with methanol, water, hydrochloric acid, and methanol. After drying, the pellets are swollen with dichloroethane, concentrated sulfuric acid is added, and the reaction is continued at 35°C for 12 hours to obtain a temperature-resistant, strongly acidic cation exchange resin.

[0027] The structure of daidzein involved in the present invention is:

[0028] .

[0029] The reaction equation of phenol and dicyclopentadiene involved in the present invention is:

[0030] .

[0031] The reaction equation of daidzein, phenol and dicyclopentadiene involved in the present invention is:

[0032] . Example 1

[0033] 24g of phenol was placed in a four-necked flask, and 6g of daidzein was added with stirring. The mixture was heated to 60°C and preheated under N2 protection. 0.9g of heat-resistant strong acidic cation exchange resin and 0.405g of phase transfer catalyst hexadecyltrimethylammonium bromide were added simultaneously, and the mixture was stirred for 0.5h. The mixture was heated to 85°C and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel for 0.5h. After the addition was complete, the mixture was kept warm for 1h. Stirring was continued until the temperature reached 110°C and the mixture was stirred for 5h. After the reaction was completed, the mixture was cooled and sodium hydroxide was added dropwise until neutral. A rotary evaporator was used for vacuum distillation at a vacuum of -0.095MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot to obtain dicyclopentadiene phenol resin modified with daidzein. Example 2

[0034] 24g of phenol was placed in a four-necked flask, and 6g of daidzein was added with stirring. The mixture was heated to 60°C. The phenol was preheated under nitrogen protection. 0.9g of a heat-resistant, strongly acidic cation exchange resin and 0.405g of a phase transfer catalyst, cetyltrimethylammonium bromide, were added simultaneously, and the mixture was stirred for 0.5h. The temperature was raised to 85°C, and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel over 0.5h. After the addition was complete, the mixture was kept warm for 1h. Stirring was continued until the temperature reached 120°C, where it was stirred for 5h. After the reaction, the mixture was cooled and sodium hydroxide was added dropwise until neutral. Vacuum distillation was performed using a rotary evaporator at a vacuum of -0.095 MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot, ultimately producing daidzein-modified dicyclopentadiene phenol resin. Example 3

[0035] 24g of phenol was placed in a four-necked flask, and 6g of daidzein was added with stirring. The mixture was heated to 60°C. The phenol was preheated under nitrogen protection. 1.2g of a heat-resistant, strongly acidic cation exchange resin and 0.405g of a phase transfer catalyst, cetyltrimethylammonium bromide, were added simultaneously, and the mixture was stirred for 0.5h. The temperature was raised to 85°C, and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel over 0.5h. After the addition was complete, the mixture was kept warm for 1h. Stirring was continued until the temperature reached 120°C, where it was stirred for 5h. After the reaction, the mixture was cooled and sodium hydroxide was added dropwise until neutral. Vacuum distillation was performed using a rotary evaporator at a vacuum of -0.095MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot, ultimately producing daidzein-modified dicyclopentadiene phenol resin. Example 4

[0036] 24g of phenol was placed in a four-necked flask, and 6g of daidzein was added with stirring. The mixture was heated to 60°C. The phenol was preheated under nitrogen protection. 1.2g of a heat-resistant, strongly acidic cation exchange resin and 0.405g of a phase transfer catalyst, cetyltrimethylammonium bromide, were added simultaneously, and the mixture was stirred for 0.5h. The temperature was raised to 85°C, and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel over 0.5h. After the addition was complete, the mixture was kept warm for 1h. Stirring was continued until the temperature reached 120°C, where it was stirred for 6h. After the reaction, the mixture was cooled and sodium hydroxide was added dropwise until neutral. Vacuum distillation was performed using a rotary evaporator at a vacuum of -0.095MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot, ultimately producing daidzein-modified dicyclopentadiene phenol resin. Example 5

[0037] To a four-necked flask, add 7.5g of daidzein, stirring, and heat to 60°C. Preheat the phenol under nitrogen protection. Simultaneously, add 1.2g of a heat-resistant, strongly acidic cation exchange resin and 0.405g of a phase transfer catalyst, cetyltrimethylammonium bromide, and stir for 0.5h. Raise the temperature to 85°C and add 10.5g of dicyclopentadiene dropwise using a constant pressure dropping funnel over 0.5h. After the addition is complete, keep the mixture warm for 1h. Continue stirring and heat to 120°C, stirring for 5h. After the reaction is complete, cool the mixture and add sodium hydroxide dropwise until neutral. Perform vacuum distillation using a rotary evaporator at a vacuum of -0.095MPa, 180°C, and 2h. Discard the mixture while hot to obtain daidzein-modified dicyclopentadiene phenol resin. Comparative Example 1

[0038] 30g of phenol was placed in a four-necked flask, stirred and heated to 60°C. Phenol was preheated under N2 protection, and 1.2g of methanesulfonic acid was added simultaneously. The mixture was insulated and stirred for 0.5h. The temperature was raised to 85°C, and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel for 0.5h. After the addition was complete, the mixture was insulated for 1h. The mixture was then heated to 120°C and stirred for 5h. After the reaction was completed, the mixture was cooled and sodium hydroxide was added dropwise until neutral. A rotary evaporator was used for vacuum distillation with a vacuum degree of -0.095MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot to obtain dicyclopentadiene phenol resin. Comparative Example 2

[0039] 24g of phenol was placed in a four-necked flask, and 6g of daidzein was added with stirring. The temperature was raised to 60°C. The phenol was preheated under nitrogen protection. 1.2g of methanesulfonic acid and 0.405g of hexadecyltrimethylammonium bromide (a phase transfer catalyst) were added simultaneously, and the mixture was stirred for 0.5h. The temperature was raised to 85°C, and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel over 0.5h. After the addition was complete, the mixture was kept warm for 1h. Stirring was continued until the temperature reached 120°C, where it was stirred for 5h. After the reaction, the mixture was cooled, and sodium hydroxide was added dropwise until neutral. Vacuum distillation was performed using a rotary evaporator at a vacuum of -0.095 MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot, ultimately producing daidzein-modified dicyclopentadiene phenol resin. Comparative Example 3

[0040] 30g of phenol was placed in a four-necked flask, stirred and heated to 60°C. The phenol was preheated under N2 protection. 1.2g of heat-resistant strong acidic cation exchange resin was added and stirred for 0.5h. The temperature was raised to 85°C and 10.5g of dicyclopentadiene was added dropwise using a constant pressure dropping funnel for 0.5h. After the addition was complete, the reaction was incubated for 1h. The temperature was continued to rise to 120°C with stirring and the reaction was stirred for 5h. After the reaction was completed, the mixture was cooled and sodium hydroxide was added dropwise until neutral. A rotary evaporator was used for vacuum distillation with a vacuum degree of -0.095MPa, a temperature of 180°C, and a time of 2h. The mixture was discharged while hot to finally obtain dicyclopentadiene phenol resin.

[0041] The performance of the brown solid resin obtained in the examples of the present invention and the comparative examples was tested, and the test results are shown in Table 1. The softening point was measured using the ring and ball method on a SYD-2806F automatic softening point tester. The sample to be tested was placed in a sample ring placed on a metal plate. The sample ring and the metal plate were placed in an oil bath and heated until the resin melted. The temperature at which the resin just touched the metal plate was recorded as the softening point of the resin. The rotational viscosity was measured using a rotational viscometer. The free phenol in the synthesized resin was determined by gas chromatography. Instrument conditions: a hydrogen flame detector was used, the inlet temperature was 220°C, the FID detector temperature was 280°C, and the injection volume was 0.2μl. The nitrogen flow rate was 20 mL / min; the hydrogen flow rate was 30 mL / min; and the air flow rate was 300 mL / min.

[0042] Table 1 Test results of different resin properties

[0043]

[0044] Among the above resins, the softening points of the examples of the present invention are all higher than those of the comparative examples, and the highest softening point of Example 2 is 113° C., which is significantly higher than that of Comparative Example 1. This indicates that the dicyclopentadiene phenol resin modified with daidzein can increase the softening point.

[0045] With the help of the data obtained by TG, the changes in the heat resistance of the examples and comparative examples were explored, and the weight loss temperatures of the resins at different percentages and the residual carbon content at different temperatures were studied. The test results are shown in Table 2.

[0046] Table 2 Thermal gravimetric test results of different resins

[0047]

[0048] Among the resins described above, the 5% and 10% weight loss temperatures, as well as the carbon residue rates at 400°C and 600°C, of ​​the examples of the present invention were higher than those of the comparative examples. Among them, Example 2 exhibited the highest 5% and 10% weight loss temperatures, at 372°C and 432°C, respectively. At 400°C and 600°C, the carbon residue rates of the resin in Example 2 were 93.0% and 58.2%, respectively, significantly higher than those of the resin in Comparative Example 1. These results demonstrate that the high-temperature stability of dicyclopentadiene phenol resin modified with daidzein in place of phenol has been significantly improved.

[0049] Table 3 Wear rates of the embodiments and comparative examples

[0050]

[0051] As shown in Table 3, the wear rates of the embodiments of the present invention are all lower than those of the comparative examples, among which the wear rate of Example 2 is the lowest, indicating that the dicyclopentadiene phenol resin modified with biomass flavonoids improves the wear resistance of the resin.

[0052] The above are merely preferred embodiments of the present invention. It should be noted that these preferred embodiments should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the scope of the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for modifying dicyclopentadiene phenol resin with flavonoid biomass, characterized in that: The modified dicyclopentadiene-phenol resin is obtained by reacting daidzein, phenol, and dicyclopentadiene as raw materials, using a heat-resistant strong acidic cation exchange resin as a catalyst, and adding a phase transfer catalyst. The mass ratio of the total mass of daidzein and phenol to the mass of dicyclopentadiene is 3:1-1.1, and daidzein accounts for 20%-25% of the total mass of daidzein and phenol. The heat-resistant strong acidic cation exchange resin is synthesized from styrene and divinylbenzene through polymerization, physical structure stabilization, halogenation, and sulfonation steps, and the sulfonic acid group of the resin is located at the ortho position of the benzene ring.

2. The method for modifying dicyclopentadiene phenol resin using flavonoid biomass according to claim 1, wherein: The specific steps include: (1) Add phenol and daidzein to the reactor, stir and heat to preheat, under N2 protection, add temperature-resistant strong acid cation exchange resin and phase transfer catalyst, stir and heat; Dicyclopentadiene was added dropwise under stirring, and after the addition was complete, the temperature was raised with stirring to react, and after the reaction was complete, the reaction was cooled to obtain a reaction product; (2) The pH of the obtained product is adjusted to neutral, and the temperature is increased and the pressure is reduced to remove the phenol to obtain the dicyclopentadiene phenol resin modified with daidzein.

3. The method for modifying dicyclopentadiene phenol resin using flavonoid biomass according to claim 2, wherein: The amount of the heat-resistant strong acid cation exchange resin used is 0.5% to 3% of the total reactant mass.

4. The method for modifying dicyclopentadiene phenol resin using flavonoid biomass according to claim 2, wherein: The amount of the phase transfer catalyst used is 0.9% to 1% of the total amount of the reaction materials; the phase transfer catalyst is hexadecyltrimethylammonium bromide.

5. The method for modifying dicyclopentadiene phenol resin with flavonoid biomass according to claim 2, wherein: The reaction system was heated to 80-85°C, and dicyclopentadiene was added dropwise using a constant pressure dropping funnel under stirring for 0.5 h. After the addition was completed, the mixture was kept warm for 1 h.

6. The method for modifying dicyclopentadiene phenol resin with flavonoid biomass according to claim 2, wherein: The reaction temperature is 100-140°C and the reaction time is 3-7h.

7. The method for modifying dicyclopentadiene phenol resin with flavonoid biomass according to claim 2, wherein: The vacuum degree of reduced pressure dephenolization is -0.095MPa, the temperature is 180-190℃, and the time is 2h.

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