Novolac epoxy resin and method for producing same

Abstract

The invention relates to novolac epoxy resin and a manufacturing method thereof. The manufacturing method of the novolac epoxy resin comprises the following steps: adding cardanol and vanillin into a reaction tank; heating the reaction tank, and adding an acid catalyst when the temperature is 60-90 DEG C, so that the cardanol and the vanillin are subjected to condensation polymerization to generate phenolic resin; and carrying out substitution reaction on the mixed phenolic resin and epichlorohydrin at the temperature of 55-70 DEG C to generate the novolac epoxy resin. Vanillin is a limited reagent. The acidity coefficient pKa value of the acidic catalyst in water at 25 DEG C is less than 3.1.

Description

Technical Field

[0001] This application relates to a phenolic epoxy resin and a method for manufacturing the same, and more particularly to a method for preparing phenolic epoxy resin using biomass materials. Background Technology

[0002] Thermosetting epoxy resins possess excellent overall properties and are widely used in coatings, adhesives, encapsulants, and composite materials. However, the main source of existing epoxy resins is petrochemicals.

[0003] Taking hydroquinone-based epoxy resin, which currently has the highest production volume, as an example, although there is mature biomass technology for epichlorohydrin, the key material for producing hydroquinone-based epoxy resin, the source of hydroquinone is still petroleum cracking. Furthermore, hydroquinone is known to be biotoxic, and many countries have explicitly banned its use in materials that come into contact with food or the human body.

[0004] Therefore, given the oil shortage, rising environmental awareness, and limited applications due to biotoxicity, research institutions are committed to finding monomers that can replace propionol in order to overcome the above problems and produce epoxy resins made entirely from biomass materials, thus contributing to environmental protection.

[0005] Therefore, how to improve the material structure to prepare epoxy resins using biomass materials as raw materials and overcome the above-mentioned defects has become one of the important issues that this project aims to solve. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide a phenolic epoxy resin and a method for manufacturing the same, addressing the shortcomings of the prior art.

[0007] To address the aforementioned technical problems, one technical solution adopted by this invention is to provide a method for manufacturing phenolic epoxy resin. The method includes: adding cashew nut shellac and vanillin to a reaction tank; heating the reaction tank; adding an acidic catalyst when the temperature reaches 60°C to 90°C to induce a condensation reaction between cashew nut shellac and vanillin to generate phenolic resin; and then, at a temperature of 55°C to 70°C, reacting the mixed phenolic resin with epichlorohydrin in a substitution reaction to generate phenolic epoxy resin. Vanillin is a limited-quantity reagent. The acidic catalyst has an acidity coefficient (pKa) of less than 3.1 in water at 25°C.

[0008] Furthermore, the acidity coefficient pKa of the acid catalyst in water at 25°C is between -2 and 1.5.

[0009] Furthermore, with a total weight of 100 parts by weight of cashew phenol and vanillin, the amount of acidic catalyst added is 0.25 to 1 part by weight.

[0010] Furthermore, the acidic catalyst is methanesulfonic acid.

[0011] Furthermore, the method for manufacturing phenolic epoxy resin further includes: after the step of generating phenolic resin, adding an alkaline solution to the reactor to terminate the polycondensation reaction.

[0012] Furthermore, the alkaline solution is an aqueous solution of sodium hydroxide.

[0013] Furthermore, after adding the alkaline solution, an acidic substance is added to adjust the pH value of the phenolic resin to 6.5 to 7.5.

[0014] Furthermore, the acidic substance is oxalic acid.

[0015] Furthermore, the method for manufacturing phenolic epoxy resin further includes: after adding an acidic substance, adding an extraction solvent to extract and obtain phenolic resin, and then mixing the phenolic resin with epichlorohydrin to carry out a substitution reaction, wherein the extraction solvent is selected from the group consisting of ethyl acetate, toluene and methyl isobutyl ketone.

[0016] Furthermore, a substitution reaction is carried out between a mixed phenolic resin, epichlorohydrin, and a surfactant, wherein the surfactant is an alcohol ether solvent.

[0017] Furthermore, the molecular weight of phenolic resin is from 4,000 g / mol to 10,000 g / mol.

[0018] Furthermore, the hydroxyl equivalent of the phenolic resin is 200 g / equivalent to 250 g / equivalent.

[0019] To address the aforementioned technical problems, another technical solution adopted by the present invention is to provide a phenolic epoxy resin. The phenolic epoxy resin is prepared by the aforementioned method.

[0020] One of the beneficial effects of the present invention is that the phenolic epoxy resin and its manufacturing method provided by the present invention can produce phenolic epoxy resin made of biomass materials by means of the technical solution of "adding cashew phenol and vanillin to the reaction tank" and "the acidity coefficient pKa value of the acid catalyst in water at 25°C is less than 3.1", and can replace the existing petrochemical-derived phenolic epoxy resin.

[0021] To gain a further understanding of the features and technical content of this application, please refer to the following detailed description and accompanying drawings. However, the drawings provided are for reference and illustration only and are not intended to limit this application. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the steps of the method for manufacturing the phenolic epoxy resin of the present invention.

[0023] Figure 2 This is a schematic diagram illustrating the reaction mechanism between the phenolic resin and epichlorohydrin of the present invention. Detailed Implementation

[0024] The following specific examples illustrate the embodiments of the "phenolic epoxy resin and its manufacturing method" disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention. In addition, the term "or" as used herein may include, depending on the actual situation, any combination of any one or more of the associated listed items.

[0025] To overcome the problems of toxicity of the aforementioned raw materials and the shortage of petrochemical raw materials, this invention, through the selection of synthetic monomers, produces phenolic epoxy resins entirely from biomass materials, thus contributing to environmental protection. After selecting specific biomass materials, the synthesis steps need to be adjusted according to their characteristics to synthesize commercially viable materials.

[0026] Specifically, this invention uses cashew phenol and vanillin as raw materials, which undergo a condensation reaction to synthesize phenolic resin (steps S1 to S5). The phenolic resin is then subjected to a substitution reaction with epichlorohydrin (steps S6 to S10) to obtain a phenolic epoxy resin made entirely from biomass materials. Therefore, the phenolic epoxy resin of this invention can be used to replace existing bisphenol A type phenolic epoxy resin.

[0027] Cashew phenol and vanillin are both derived from biomass materials. Cashew phenol can replace commonly used phenol (e.g., bisphenol A), and vanillin can replace highly toxic formaldehyde. Therefore, the structural formula of the phenolic resin of this invention can be represented as follows:

[0028] Where n is a positive integer from 5 to 25.

[0029] Please see Figure 1As shown, the method for manufacturing the phenolic epoxy resin of the present invention includes the following steps S1 to S10: mixing cashew phenol and vanillin (step S1); adding an acidic catalyst to carry out a polycondensation reaction (step S2); adding an alkaline solution to terminate the polycondensation reaction (step S3); adding an acidic substance to adjust the pH to neutral (step S4); adding an extraction solvent to obtain phenolic resin (step S5); mixing phenolic resin, epichlorohydrin, and a surfactant (step S6); adding a first alkaline solution to carry out a dehydrogenation reaction (step S7); adding a second alkaline solution to carry out a ring-closing reaction (step S8); removing the remaining epichlorohydrin (step S9); adding an extraction solvent to obtain phenolic epoxy resin (step S10).

[0030] In step S1, cashew phenol and vanillin are added to the reaction vessel. Vanillin is a limited reagent, meaning that the molar amount of cashew phenol added is greater than that of vanillin. This ensures that both ends of the synthesized phenolic resin are hydroxyl groups, which is beneficial for subsequent substitution reactions.

[0031] In a preferred embodiment, to ensure the specificity of the reaction, nitrogen gas can be introduced into the reaction tank to allow cashew phenol and vanillin to undergo a condensation reaction under a nitrogen atmosphere.

[0032] In step S2, in order to accelerate the polycondensation reaction of cashew phenol and vanillin, the reaction tank is heated to a temperature of 60°C to 90°C, and then an acidic catalyst is added so that cashew phenol and vanillin can undergo a polycondensation reaction to generate phenolic resin.

[0033] It is worth noting that weak acids were previously used in the condensation reaction of formaldehyde and phenol. Since cashew phenol and vanillin have poor reactivity, this invention uses a stronger acid catalyst to facilitate the condensation reaction. Specifically, the acid catalyst has an acidity coefficient pKa of less than 3.1 in water at 25°C.

[0034] When the acidity coefficient pKa of an acidic catalyst is low (e.g., hydrochloric acid, sulfuric acid, phosphoric acid), the acidic catalyst can dissociate more hydrogen ions, resulting in more intense exothermic reaction during the polycondensation reaction, making it difficult to control the reaction and leading to a wider molecular weight distribution range of phenolic resin (higher polymer dispersibility index).

[0035] When the acidity coefficient pKa of an acidic catalyst is high (e.g., citric acid, oxalic acid), the acidic catalyst is less likely to dissociate into hydrogen ions, resulting in a weaker reactivity between cashew phenol and vanillin, leading to a lower molecular weight of phenolic resin.

[0036] After experimental testing, the preferred acidity coefficient pKa value of the acid catalyst in water at 25°C is between -2.9 and 1.5, more preferably between -2.0 and -1.5. For example, the acid catalyst can be methanesulfonic acid or p-toluenesulfonic acid, with methanesulfonic acid being the best.

[0037] In order to control the reaction stability of the polycondensation reaction, in addition to temperature and type of acid catalyst, the present invention also controls the amount of acid catalyst added. With a total weight of cashew phenol and vanillin of 100 parts by weight, the amount of acid catalyst added is 0.25 parts by weight to 1 part by weight, preferably 0.5 parts by weight to 0.6 parts by weight.

[0038] In step S3, the vanillin content in the reaction tank is detected by liquid chromatography (LC). When the weight percentage concentration of vanillin in the reaction tank is less than 0.1%, an alkaline solution is added to terminate the polycondensation reaction. In one exemplary embodiment, the polycondensation reaction in step S2 generally lasts for 3.5 to 4.5 hours.

[0039] Specifically, the addition of an alkaline solution can neutralize the acidic catalyst, thereby terminating the polycondensation reaction. The alkaline solution can be a 40wt% to 60wt% aqueous solution of sodium hydroxide or a 40wt% to 60wt% aqueous solution of potassium hydroxide, but the present invention is not limited thereto.

[0040] In step S4, an acidic substance is added to the reaction tank to adjust the solution's pH to neutral (i.e., pH 6.5 to 7.5) to prevent the generated phenolic resin from decomposing. For example, the acidic substance can be oxalic acid. However, the amount of acidic substance added is not limited; the main purpose is to maintain the pH of the reaction tank at neutral.

[0041] Through the above steps S1 to S4, the reaction tank contains a variety of organic and aqueous substances, so phenolic resin can be purified by water washing and extraction.

[0042] In step S5, the mixture is washed with water using an extraction solvent, resulting in the formation of an organic phase and an aqueous phase in the reaction tank. The phenolic resin is present in the organic phase. Therefore, the aqueous phase can be removed by reflux dehydration at a temperature of 110°C to 130°C, followed by removal of the extraction solvent under a pressure of 5 to 400 tones to obtain the phenolic resin.

[0043] Experimental testing showed that the extraction solvent can be selected from the group consisting of ethyl acetate, toluene, and methyl isobutyl ketone. When the extraction solvent is one of the above substances, it exhibits a superior extraction effect on phenolic resins, with methyl isobutyl ketone being the most effective.

[0044] Furthermore, tests were conducted using cashew nut shell extract of different purities. The results showed that the higher the purity of the cashew nut shell extract, the lighter the color of the resulting phenolic resin. Specifically, cashew nut shell extract of model Cardley NX-2024 with a purity greater than or equal to 87% produced a darker-colored phenolic resin; while cashew nut shell extract of model Cardley NX-2026 with a purity greater than or equal to 96% produced a lighter-colored phenolic resin.

[0045] In step S6, the phenolic resin, epichlorohydrin (ECH), and surfactant obtained in step S5 are mixed. The surfactant helps the compatibility between the phenolic resin and epichlorohydrin, thereby promoting the reaction between epichlorohydrin and the phenolic resin to replace the hydroxyl groups of the phenolic resin with epoxy groups.

[0046] Specifically, surfactants can be alcohol ether solvents. For example, surfactants can be selected from the group consisting of: ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether.

[0047] In a preferred embodiment, the amount of epichlorohydrin added is 400 to 800 parts by weight relative to 100 parts by weight of phenolic resin. For example, the amount of epichlorohydrin added can be 450, 500, 550, 600, 650, 700, or 750 parts by weight. More preferably, the amount of epichlorohydrin added is 600 to 700 parts by weight relative to 100 parts by weight of phenolic resin.

[0048] In steps S7 and S8, the reaction tank is heated to 55°C to 70°C, and a first alkaline solution is added sequentially to carry out a dehydrogenation reaction. Then, a second alkaline solution is added to carry out a ring-closing reaction to obtain phenolic epoxy resin. In a preferred embodiment, the reaction temperature of the ring-closing reaction is higher than that of the dehydrogenation reaction, and the temperature difference between the two reactions is 5°C to 10°C.

[0049] Please refer to Figure 2 As shown, Figure 2 This example illustrates the reaction mechanism between phenolic resin and epichlorohydrin in steps S7 and S8. Figure 2 In the illustrated example, the first alkaline solution is a 50 wt% aqueous sodium hydroxide solution. The addition of this first alkaline solution helps remove hydrogen atoms from the hydroxyl groups on the phenolic resin. In the presence of the surfactant, the reaction between epichlorohydrin and the phenolic resin is facilitated, replacing the original hydroxyl groups on the phenolic resin with epoxy groups. The second alkaline solution is also a 50 wt% aqueous sodium hydroxide solution. The addition of this second alkaline solution helps epichlorohydrin undergo dechlorination and ring closure, completing the substitution reaction.

[0050] The types of the first alkaline solution and the second alkaline solution are not limited to those mentioned above. The first alkaline solution and the second alkaline solution can be the same or different. For example, the first alkaline solution and the second alkaline solution can each be a 50wt% potassium hydroxide aqueous solution.

[0051] In one exemplary embodiment, the amount of the first alkaline solution added is greater than the amount of the second alkaline solution added, for example, the amount of the first alkaline solution added is 2.5 to 4 times the amount of the second alkaline solution added.

[0052] In step S7, the reactor is heated to 55°C to 65°C, and then a first alkaline solution is added dropwise to initiate a dehydrogenation reaction, removing hydrogen atoms from the hydroxyl groups on the phenolic resin. For example, the dropwise rate of the first alkaline solution is 0.1 g / min to 0.4 g / min. To observe the extent of the dehydrogenation reaction, the phenolic resin is irradiated with ultraviolet light at a wavelength of 310 nm, and the hydroxyl content in the phenolic resin is quantified by the absorbance value. When the hydroxyl equivalent of the phenolic resin is less than 3% of the original hydroxyl equivalent of the phenolic resin, a second alkaline solution is added to proceed to step S8.

[0053] In one exemplary embodiment, the first alkaline solution is added dropwise over 1.5 to 3.5 hours, so the dehydrogenation reaction in step S7 generally takes 1.5 to 3.5 hours. Furthermore, after the first alkaline solution is added, stirring is continued for 30 minutes to ensure that the hydroxyl groups on the phenolic resin have been completely dehydrogenated. Next, the temperature is raised to 65°C, and dehydration is performed for 30 minutes under a pressure of 5 to 400 tors. Water is generated during the dehydrogenation reaction, but the presence of water can lead to hydrolysis of the phenolic resin. Therefore, after the dehydrogenation reaction is complete, a dehydration treatment is performed before proceeding to step S8.

[0054] In step S8, the reactor is heated to 60°C to 70°C, and then a second alkaline solution is added dropwise to initiate a ring-closure reaction, thereby dechlorinating and ring-closing epichlorohydrin. For example, the dropping rate of the second alkaline solution is 0.05 g / min to 0.15 g / min. In an exemplary embodiment, the dropping time of the second alkaline solution is 1 hour to 2.5 hours, so the ring-closure reaction in step S8 generally takes 1 hour to 2.5 hours. Furthermore, after the second alkaline solution is completely added, the temperature is raised to 75°C within 30 minutes and dehydrated for 30 minutes.

[0055] In step S9, unreacted epichlorohydrin is removed at a temperature of 120°C to 130°C to avoid epichlorohydrin affecting the purity of the phenolic epoxy resin.

[0056] In step S10, when the reactor temperature is cooled to 70°C to 80°C, an extraction solvent and a neutralization solution are added under normal pressure for water washing, thereby forming an organic phase and an aqueous phase in the reaction tank. The extraction solvent extracts the phenolic epoxy resin into the organic phase, and the neutralization solution reacts with the chloride ions removed by epichlorohydrin to form sodium chloride salts. Next, the mixture is refluxed at 110°C to 130°C to remove the aqueous phase, and then the extraction solvent is removed under a pressure of 5 to 400 tones to obtain the phenolic epoxy resin.

[0057] After experimental testing, the extraction solvent can be selected from the group consisting of ethyl acetate, toluene, and methyl isobutyl ketone, with methyl isobutyl ketone being preferred. The neutralization solution can be a 35 wt% aqueous solution of sodium hydroxide. However, the present invention is not limited thereto.

[0058] Synthesis of phenolic epoxy resin

[0059] To verify that the manufacturing method of the present invention can be used to synthesize phenolic epoxy resins, phenolic resins of Examples 1 to 3 were prepared according to steps S1 to S5 described above. After preparation, the weight-average molecular weight of the phenolic resins was measured using a gel permeation chromatography (GPC) instrument, and the hydroxyl equivalent of the phenolic resins was measured using a potential titrator. The results are listed in Table 1.

[0060] According to steps S6 to S10 above, the phenolic resin of Example 1 was mixed with epichlorohydrin and a surfactant to prepare the phenolic epoxy resins of Examples 4 to 6. After preparation, the epoxy equivalent of the phenolic epoxy resin was measured using a potential titrator, and the viscosity of the phenolic epoxy resin was measured using a viscometer at 25°C. The results are listed in Table 2.

[0061] [Example 1]

[0062] 190 g (0.63 mol equivalent) of cashew phenol and 76 g (0.5 mol equivalent) of vanillin were added to the reaction vessel, and nitrogen gas was introduced to maintain a nitrogen atmosphere inside the reactor. The reactor was heated, and when the temperature reached 70°C, 1.5 g of methanesulfonic acid (acidic catalyst) was added, and a polycondensation reaction was carried out for 4 hours.

[0063] After the reaction was complete, 1 gram of 50 wt% sodium hydroxide aqueous solution (alkaline solution) and 0.1 gram of oxalic acid (acidic substance) were added to terminate the polycondensation reaction, and the mixture was then extracted and washed with water using methyl isobutyl ketone (extraction solvent). After washing, the reactor was heated to 120°C for reflux dehydration, and the extraction solvent was removed under a pressure of 10 tors to obtain phenolic resin.

[0064] The phenolic resin in Example 1 is a light yellow liquid with a weight-average molecular weight of 7406 g / mol and a hydroxyl equivalent of 230 g / equivalent.

[0065] [Example 2]

[0066] The operating conditions for Example 2 were similar to those for Example 1, except that the polycondensation reaction in Example 2 was carried out at a temperature of 65°C. The phenolic resin in Example 2 was a light yellow liquid with a weight-average molecular weight of 5329 g / mol and a hydroxyl equivalent of 242 g / equivalent.

[0067] [Example 3]

[0068] The operating conditions for Example 3 were similar to those for Example 1, except that the polycondensation reaction in Example 3 was carried out at a temperature of 85°C. The phenolic resin in Example 3 was a light yellow liquid with a weight-average molecular weight of 9593 g / mol and a hydroxyl equivalent of 223 g / equivalent.

[0069] Table 1

[0070]

[0071] As shown in Table 1, steps S1 to S5 according to the present invention can produce biomass phenolic resin using cashew phenol and vanillin as raw materials. Furthermore, the weight-average molecular weight of the phenolic resin increases with increasing temperature of the polycondensation reaction.

[0072] When the polycondensation reaction temperature is between 60°C and 90°C, the weight-average molecular weight of the phenolic resin can be between 4000 g / mol and 10000 g / mol. In other embodiments, the polycondensation reaction temperature can be a positive integer between 60°C and 90°C, and the weight-average molecular weight of the phenolic resin can be a positive integer between 4000 g / mol and 10000 g / mol.

[0073] In addition, the hydroxyl equivalent of phenolic resin can be from 200 g / equivalent to 250 g / equivalent, for example: 210 g / equivalent, 220 g / equivalent, 230 g / equivalent or 240 g / equivalent.

[0074] [Example 4]

[0075] Add 150 g of the phenolic resin obtained from Example 1, 990 g of epichlorohydrin, and 125 g of diethylene glycol monomethyl ether (surfactant) to the reactor.

[0076] After heating the reactor to 60°C, 99 g of 50 wt% sodium hydroxide aqueous solution (the first alkaline solution) was added dropwise to initiate the dehydrogenation reaction, with a total adding time of 2.5 hours. After the addition was complete, the mixture was stirred for 30 minutes to ensure complete dehydrogenation of the phenolic resin. After heating the reactor to 65°C, dehydration was carried out for 30 minutes under a pressure of 190 torts.

[0077] Next, 33 g of 50 wt% sodium hydroxide aqueous solution (second alkaline solution) was added dropwise to initiate the ring-closing reaction, with a total addition time of 2 hours. After the addition was completed, the temperature was raised to 75°C within 30 minutes to remove moisture, and then further raised to 125°C to remove the remaining epichlorohydrin.

[0078] When the reactor temperature drops to 75°C, 200g of ethyl acetate (extraction solvent) and 15g of 35wt% sodium hydroxide aqueous solution (neutralization solution) are added for washing. After washing, the reactor temperature is raised to 120°C for reflux dehydration, and then the extraction solvent is removed under a pressure of 10 tors to obtain phenolic epoxy resin. The phenolic epoxy resin of Example 4 has an epoxy equivalent of 312 g / equivalent and a viscosity of 11000 cps.

[0079] [Example 5]

[0080] The operating conditions for Example 5 were similar to those for Example 4, except that the amount of epichlorohydrin added in Example 5 was 1100 g, and the dropping time of the first alkaline solution was 1.5 hours. The phenolic epoxy resin in Example 5 had an epoxy equivalent of 308 g / equivalent and a viscosity of 11300 cps.

[0081] [Example 6]

[0082] The operating conditions for Example 6 were similar to those for Example 4, except that the total dropping time of the first alkaline solution in Example 6 was 2 hours, the total dropping time of the second alkaline solution was 1.5 hours, and the extraction solvent used in washing the phenolic epoxy resin was methyl isobutyl ketone. The phenolic epoxy resin in Example 6 had an epoxy equivalent of 293 g / equivalent and a viscosity of 12100 cps.

[0083] Table 2

[0084]

[0085] As can be seen from the results in Table 2, according to steps S6 to S10 of the present invention, the terminal groups of biomass phenolic resin can be replaced with epoxy groups to obtain biomass materials that combine the excellent properties of epoxy resin and phenolic resin.

[0086] According to Examples 4 to 6 above, the epoxy equivalent of the phenolic epoxy resin can be from 250 g / equivalent to 350 g / equivalent, and the viscosity of the phenolic epoxy resin can be from 10,000 cps to 15,000 cps. In other embodiments, the epoxy equivalent of the phenolic epoxy resin can be a positive integer between 250 g / equivalent and 350 g / equivalent, and the viscosity of the phenolic epoxy resin can be a positive integer between 10,000 cps and 15,000 cps.

[0087] [Beneficial Effects of the Examples]

[0088] One of the beneficial effects of the present invention is that the phenolic epoxy resin and its manufacturing method provided by the present invention can produce phenolic epoxy resin made of biomass materials by means of the technical solution of "adding cashew phenol and vanillin to the reaction tank" and "the acidity coefficient pKa value of the acid catalyst in water at 25°C is less than 3.1", and can replace the existing petrochemical-derived phenolic epoxy resin.

[0089] The content disclosed above is only a preferred and feasible embodiment of this application, and is not intended to limit the scope of protection of the claims of this application. Therefore, all equivalent technical changes made based on the content of this application specification and drawings are included within the scope of protection of the claims of this application.

Claims

1. A method for manufacturing phenolic epoxy resin, characterized in that, The manufacturing method includes: Cashew phenol and vanillin are added to a reaction vessel; wherein, vanillin is a limited reagent. The reaction vessel is heated, and an acidic catalyst is added when the temperature reaches 60°C to 90°C to induce a condensation reaction between cashew phenol and vanillin to produce a phenolic resin; wherein the acidic catalyst has an acidity coefficient pKa value of less than 3.1 in water at 25°C; and The phenolic resin is mixed with epichlorohydrin at a temperature of 55°C to 70°C to undergo a substitution reaction to generate a phenolic epoxy resin.

2. The manufacturing method according to claim 1, characterized in that, The acidity coefficient pKa of the acidic catalyst in water at 25°C is between -2 and 1.

5.

3. The manufacturing method according to claim 1, characterized in that, The total weight of the cashew phenol and the vanillin is 100 parts by weight, and the amount of the acidic catalyst added is 0.25 parts by weight to 1 part by weight.

4. The manufacturing method according to claim 1, characterized in that, The acidic catalyst is methanesulfonic acid.

5. The manufacturing method according to claim 1, characterized in that, The manufacturing method further includes: after the step of generating the phenolic resin, adding an alkaline solution to the reaction tank to terminate the polycondensation reaction.

6. The manufacturing method according to claim 5, characterized in that, The alkaline solution is an aqueous solution of sodium hydroxide.

7. The manufacturing method according to claim 5, characterized in that, After adding the alkaline solution, an acidic substance is added to adjust the pH of the phenolic resin to 6.5 to 7.

5.

8. The manufacturing method according to claim 7, characterized in that, The acidic substance is oxalic acid.

9. The manufacturing method according to claim 7, characterized in that, The manufacturing method further includes: after adding the acidic substance, adding an extraction solvent to extract the phenolic resin, and then mixing the phenolic resin with the epichlorohydrin to carry out a substitution reaction; wherein the extraction solvent is selected from the group consisting of ethyl acetate, toluene and methyl isobutyl ketone.

10. The manufacturing method according to claim 1, characterized in that, The phenolic resin, epichlorohydrin, and surfactant are mixed and subjected to a substitution reaction; wherein the surfactant is an alcohol ether solvent.

11. The manufacturing method according to claim 1, characterized in that, The molecular weight of the phenolic resin is from 4,000 g / mol to 10,000 g / mol.

12. The manufacturing method according to claim 1, characterized in that, The hydroxyl equivalent of the phenolic resin is between 200 g / equivalent and 250 g / equivalent.

13. A phenolic epoxy resin, characterized in that, The phenolic epoxy resin is prepared by the manufacturing method according to any one of claims 1 to 12.

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