CN115785394A - Modified o-cresol formaldehyde epoxy resin and preparation method thereof - Google Patents

Abstract

The application discloses a modified o-cresol formaldehyde epoxy resin and a preparation method thereof, wherein the preparation method comprises the following steps: s10, reacting acrylic acid and resorcinol under the action of a catalyst I to generate a product A, and reacting o-cresol and paraformaldehyde under the action of a catalyst II to generate a product B; s20, mixing and reacting the product B with the product A to obtain a product C; s30, reacting the product C with epoxy chloropropane under the action of a catalyst III to generate a product D; and S40, carrying out a ring-closure reaction on the product D and an alkali solution to generate the o-cresol formaldehyde epoxy resin. The preparation method is based on the microchannel reactor, acrylic acid and resorcinol are adopted to modify the o-cresol formaldehyde epoxy resin, the preparation process is simple, and the prepared modified o-cresol formaldehyde epoxy resin has good photochemical activity, heat resistance and adhesive force.

Description

Modified o-cresol formaldehyde epoxy resin and preparation method thereof

Technical Field

The application relates to the technical field of epoxy resin products, in particular to modified o-cresol formaldehyde epoxy resin and a preparation method thereof.

Background

As a typical polyfunctional epoxy resin, a novolac type epoxy resin is a polyfunctional epoxy resin prepared by an epoxidation reaction with epichlorohydrin based on the molecular structure of the phenolic resin.

With the rapid development of the semiconductor industry, liquid photosensitive epoxy resin which is easy to be photocured, good in thickness forming, controllable in viscosity and the like is gradually adopted as an insulating layer in large-scale production. The o-cresol formaldehyde epoxy resin is polyfunctional glycidyl ether type epoxy resin, can be used as important resin for packaging electronic components, and has important significance for research on the o-cresol formaldehyde epoxy resin in practical application. The literature (synthesis and performance of photosensitive novolac epoxy resin, li shi rong guan shi long, wu li coating industry, 2000, 5-9) reports that the introduction of acrylic acid can enhance the optical ring chemical activity of the resin, but has a bad influence on the heat resistance and adhesion of the resin. Patent CN113736040A also proposes a preparation method of acrylic modified epoxy resin, which can greatly improve the shear strength and bending strength of the adhesive when used as an epoxy adhesive. The patent CN111848883A discloses a preparation method of a waterborne acrylic modified epoxy resin, and the obtained modified resin is mixed with a phase-change material, silica sol, graphene and the like to prepare a waterborne coating with good corrosion resistance and strong adhesive force, i.e., the adhesive force of the resin is enhanced by adding materials subsequently in the synthetic resin, so that the application range is limited.

At present, the acrylic acid modified o-cresol formaldehyde epoxy resin has the following problems: 1. the acrylic acid alone is used for modifying the o-cresol formaldehyde epoxy resin, so that the adhesive force and the heat resistance of the resin are reduced. 2. The gel risk is easy to occur in the traditional preparation process, the reaction time is long, and the reaction efficiency and the raw material utilization rate are low. 3. The application range of the acrylic acid singly modified phenolic resin is small.

Disclosure of Invention

In view of the problems of the prior art, the application provides a modified o-cresol formaldehyde epoxy resin and a preparation method thereof, wherein acrylic acid and resorcinol are adopted to modify the o-cresol formaldehyde epoxy resin so as to improve the photochemical activity, heat resistance and adhesive force of the resin.

The preparation method of the modified o-cresol formaldehyde epoxy resin comprises the following steps:

s10, reacting acrylic acid and resorcinol under the action of a catalyst I to generate a product A, and reacting o-cresol and paraformaldehyde under the action of a catalyst II to generate a product B;

s20, mixing and reacting the product B with the product A to obtain a product C;

s30, reacting the product C with epoxy chloropropane under the action of a catalyst III to generate a product D;

and S40, carrying out ring-closure reaction on the product D and an alkali solution to generate the modified o-cresol formaldehyde epoxy resin.

The specific reaction formula of the preparation method is shown in figures 1-4.

Optionally, the catalyst I is at least one of sodium ethoxide, sodium hydride and sodium amide.

Optionally, the catalyst II is at least one of oxalic acid, acetic acid and p-toluenesulfonic acid.

Optionally, the catalyst III is a quaternary ammonium salt catalyst; for example, at least one of benzyltriethylammonium chloride, tetramethylammonium chloride and tetrabutylammonium chloride.

Alternatively, the alkali solution is a sodium hydroxide solution, such as a 70-80wt% NaOH solution.

Optionally, steps S10 to S40 are all performed in the microchannel reactor.

Optionally, the microchannel reactor includes:

a container I, wherein the reaction of the acrylic acid and the resorcinol in the step S10 is carried out in the container I, the reaction temperature is 110-120 ℃, and the reaction time is 3-5min;

a container II, wherein the o-cresol and the paraformaldehyde in the step S10 are carried out in the container II, the reaction temperature is 90-110 ℃, and the reaction time is 8-10min;

a container III, wherein the step S20 is carried out in the container III, the reaction temperature is 90-110 ℃, and the reaction time is 2-4min;

a container IV, wherein the step S30 is carried out in the container IV, the reaction temperature is 85-95 ℃, and the reaction time is 4-6min;

and (5) a vessel V, wherein the step S40 is carried out in the vessel V, the reaction temperature is 60-70 ℃, and the reaction time is 1-2min.

The addition of the reagents and the transfer of the reaction solution between the containers are realized by pumps, and the specific process flow is shown in FIG. 5.

Optionally, in step S10, the molar ratio of acrylic acid to resorcinol is 1:2-4; preferably 1:2.5-3.5.

Optionally, in step S10, the catalyst I is 0.5 to 2% by mass of acrylic acid; preferably 0.8 to 1.8%.

Optionally, in step S10, the molar ratio of paraformaldehyde to o-cresol is 1; preferably 1.

Optionally, in step S10, the catalyst II is 2 to 4% of the mass of o-cresol; preferably 2.5-4%.

Optionally, the mass ratio of the product A in the step S20 to the o-cresol in the step S10 is 0.5-1.

Optionally, the molar ratio of the epichlorohydrin in step S30 to the product a in step S20 is 4-8:1; preferably 5 to 7.

Optionally, the molar ratio of the catalyst III to the product a in step S20 is 0.01 to 0.03.

Optionally, the molar ratio of the alkali in the alkali solution in the step S40 to the product B in the step S20 is 3-5; preferably 3.5 to 4.5.

Optionally, the preparation method further comprises refining, and the refining comprises the specific steps of:

removing Epichlorohydrin (ECH) reacted in the step S40, and cleaning by using a solvent;

adding an alkali solution for reaction;

and after the reaction is finished, sequentially washing with water to be neutral, and removing the solvent to obtain the modified o-cresol formaldehyde epoxy resin.

Optionally, the refining is performed in a tank reactor.

Optionally, the solvent is at least one of an organic solvent and deionized water.

Wherein the organic solvent is at least one of methyl isobutyl ketone, methanol and n-butanol.

Optionally, the base solution is a sodium hydroxide solution, for example a 15wt% sodium hydroxide solution.

Optionally, the molar ratio of the sodium hydroxide to the product A is 1-2:1.

optionally, the reaction temperature is 80-90 ℃ and the reaction time is 2-3h.

The application also provides the modified o-cresol formaldehyde epoxy resin prepared by any one of the preparation methods.

The modified o-cresol formaldehyde epoxy resin can still be applied to the field of electronic packaging due to enhanced heat resistance, adhesive force and the like, and meanwhile, due to photochemical activity and strong adhesive force, the o-cresol formaldehyde epoxy resin can not be crosslinked and cured in the painting process after being made into paint, and can be immediately cured by illumination after being painted, so that painted samples can be immediately stacked after being subjected to light treatment, the production process is simplified, and the storage space is saved.

Compared with the prior art, the method has the following technical effects:

(1) Acrylic acid and resorcinol are adopted to modify the o-cresol formaldehyde epoxy resin, so that the photochemical activity, heat resistance and adhesive force of the o-cresol formaldehyde epoxy resin can be obviously improved;

(2) The preparation process is carried out in the microchannel reactor, so that the utilization rate of raw materials, safety (prevention of gel risk) and time efficiency are improved.

Drawings

FIG. 1 is a diagram of a specific reaction formula involved in step S10 of the preparation method of the modified o-cresol formaldehyde epoxy resin;

FIG. 2 is a diagram showing a specific reaction scheme involved in step S20;

FIG. 3 is a diagram showing a specific reaction scheme involved in step S30;

FIG. 4 is a diagram of a specific reaction involved in step S40;

FIG. 5 is a flow chart of the preparation of the modified o-cresol formaldehyde epoxy resin in one embodiment of the present application.

Detailed Description

The technical solutions described in the present application will be further described with reference to the following embodiments, but the present application is not limited thereto.

Example 1

Adding 115kg of resorcinol, 150kg of acrylic acid and 2kg of sodium amide into a mixer, uniformly mixing, pumping the mixture I into a reaction module I of a microchannel reactor, controlling the temperature to 120 ℃, staying for reaction for 3min, obtaining a product A after the reaction is finished, and feeding the product A into a reaction module III of the microchannel reactor. Uniformly mixing 1000kg of preheated and melted o-cresol, 236kg of paraformaldehyde and 200kg of oxalic acid, adding the mixture into a microchannel reactor reaction module II by using a pump II, controlling the temperature to 100 ℃ and staying for reaction for 10min to obtain a product B after the reaction is finished, staying for reaction for 4min with the product A in the reactor reaction module III, then cooling to normal temperature, uniformly mixing the product B with 4283.75kg of epoxy chloropropane and 21.25kg of benzyltriethylammonium chloride, pumping the mixture into a microchannel reactor reaction module IV by using the pump III, controlling the temperature of the reaction module IV to be 90 ℃, staying for reaction for 4min to obtain a product D, pumping the product D into a microchannel reactor reaction module V by using the pump IV to perform a ring-closing reaction, controlling the temperature to 70 ℃ and staying for reaction for 1min to obtain a crude product, and transferring the crude product into a kettle-type reactor for refining; removing epoxy chloropropane in a kettle type reactor; then adding 800kg of MIBK and 400kg of deionized water, and stirring to discharge a dilute sodium hydroxide solution; then adding NaOH (15%), heating to 85 ℃, reacting for 2h, after the reaction is finished, washing to be neutral, removing the solvent, discharging the product to obtain the o-cresol formaldehyde epoxy resin modified by the acrylic acid and the resorcinol, and cooling to obtain 1889kg of yellow solid resin.

Example 2

Adding 115kg of resorcinol, 150kg of acrylic acid and 2.5kg of sodium ethoxide into a mixer, uniformly mixing, pumping the mixture I into a reaction module I of a microchannel reactor, controlling the temperature to 120 ℃, standing for reaction for 3min, and after the reaction is finished, obtaining a product A and feeding the product A into a reaction module III of the microchannel reactor. Uniformly mixing 1000kg of preheated and molten o-cresol, 248kg of paraformaldehyde and 200kg of oxalic acid, adding the mixture into a microchannel reactor reaction module II by using a pump II, controlling the temperature to 105 ℃ and staying for reaction for 8min to obtain a product B after the reaction is finished, staying for reaction for 3min with the product A in the reactor reaction module III, then cooling to normal temperature, uniformly mixing the product with 4509.88kg of epoxy chloropropane and 21.25kg of tetramethylammonium chloride, pumping the mixture into a microchannel reactor reaction module IV by using a pump III, controlling the temperature of the reaction module IV to 95 ℃, staying for reaction for 4min to obtain a product D, pumping the product D into a microchannel reactor reaction module V by using a pump IV to perform a ring-closing reaction, controlling the temperature to 70 ℃, staying for reaction for 1min to obtain a crude product, and transferring the crude product into a kettle reactor for refining; removing epoxy chloropropane in a kettle type reactor; then adding 800kg of MIBK and 400kg of deionized water, and stirring to discharge dilute sodium hydroxide solution; then NaOH (15%) is continuously added, the temperature is raised to 85 ℃, the temperature is kept for reaction for 2h, after the reaction is finished, water washing is carried out until the reaction product is neutral, the solvent is removed, the product is discharged, the o-cresol formaldehyde epoxy resin modified by acrylic acid and resorcinol is obtained, and 1987kg of yellow solid resin is obtained after cooling.

Example 3

Adding 115kg of resorcinol, 150kg of acrylic acid and 2kg of sodium amide into a mixer, uniformly mixing, pumping the mixture I into a reaction module I of a microchannel reactor, controlling the temperature to be 120 ℃, staying for reaction for 2min, obtaining a product A after the reaction is finished, and feeding the product A into a reaction module III of the microchannel reactor. Uniformly mixing 1000kg of preheated and molten o-cresol, 248kg of paraformaldehyde and 100kg of p-toluenesulfonic acid, adding the mixture into a microchannel reactor reaction module II by using a pump II, controlling the temperature to 95 ℃ and staying for reaction for 8min to obtain a product B after the reaction is finished, adding the product B into a reactor reaction module III, continuously reacting with the product A for 3min, then cooling to normal temperature, uniformly mixing the product B with 4283.75kg of epoxy chloropropane and 22.16kg of tetramethylammonium chloride, pumping the mixture into a microchannel reactor reaction module IV by using the pump III, controlling the temperature of the reaction module IV to 90 ℃, staying for reaction for 4min to obtain a product D, pumping the product D into a microchannel reactor reaction module V by using the pump IV to perform a ring-closing reaction, controlling the temperature to 70 ℃, staying for reaction for 1min to obtain a crude product, and transferring the crude product into a kettle reactor for refining; removing epoxy chloropropane in a kettle type reactor; then adding 800kg of MIBK and 400kg of deionized water, stirring and draining; and then continuously adding NaOH (15%), heating to 85 ℃, reacting for 2 hours, after the reaction is finished, washing with water to be neutral, removing the solvent, discharging the product to obtain the acrylic acid and resorcinol modified o-cresol formaldehyde epoxy resin, and cooling to obtain 1828kg of yellow solid resin.

Example 4

Adding 115kg of resorcinol, 150kg of acrylic acid and 2kg of sodium hydride into a mixer, uniformly mixing, pumping the mixture I into a reaction module I in a microchannel reactor, controlling the temperature to be 120 ℃, staying for reaction for 1min, obtaining a product A after the reaction is finished, and feeding the product A into a reaction module III of the microchannel reactor. Uniformly mixing 1000kg of preheated and molten o-cresol, 236kg of paraformaldehyde and 200kg of oxalic acid, adding the mixture into a microchannel reactor reaction module II by using a pump II, controlling the temperature to 100 ℃ and staying for reaction for 9min to obtain a product B, adding the product B into a reactor reaction module III, continuously reacting with the product A for 3min, then cooling to normal temperature, uniformly mixing the product B with 4283.75kg of epoxy chloropropane and 21.25kg of tetrabutyl ammonium chloride, pumping the mixture into a microchannel reactor reaction module IV by using a pump III, controlling the temperature of the reaction module IV to 90 ℃, staying for reaction for 4min to obtain a product D, pumping the product D into a microchannel reactor reaction module V by using a pump IV to perform a ring-closing reaction, controlling the temperature to 70 ℃, staying for reaction for 2min to obtain a crude product, and transferring the crude product into a kettle-type reactor to be refined; removing epoxy chloropropane in a kettle type reactor; adding 800kg of n-butyl alcohol and 400kg of deionized water, stirring and draining; then adding NaOH (15%), heating to 85 ℃, keeping the temperature and reacting for 2h, after the reaction is finished, washing with water to be neutral, removing the solvent, discharging the product to obtain the acrylic acid and resorcinol modified o-cresol formaldehyde epoxy resin, and cooling to obtain 1801kg of yellow solid resin.

Comparative example 1

Adding 1000kg of preheated and melted o-cresol into a high-position metering tank by using a special pump, metering and adding the o-cresol into a reaction kettle, then adding 236kg of paraformaldehyde and 200kg of oxalic acid, heating to 100 ℃, carrying out heat preservation reaction for 6 hours, dehydrating to 160 ℃ under normal pressure after the reaction is finished, then carrying out dephenolization and desolvation under reduced pressure, keeping the vacuum degree at more than-0.09 Mpa, stopping the reaction after the reaction lasts for 2 hours after the reaction is finished to 195 ℃, then cooling to normal temperature, adding 4283.75kg of epoxy chloropropane, 21.25kg of benzyltriethylammonium chloride, heating to 90 ℃, carrying out heat preservation reaction for 4 hours, cooling to 70 ℃ after the reaction is finished, then adding 24.7kg of caustic soda flakes every 12 minutes, finishing the addition of 2h, continuing the heat preservation reaction for 1.5 hours, carrying out the reaction and carrying out the vacuum dephenolization and desoxychloropropane at 160 ℃ under reduced pressure until the vacuum degree is more than-0.08 Mpa; then adding 800kg of MIBK and 400kg of deionized water, stirring for 10min, standing and draining; then adding NaOH (15%), heating to 85 ℃, keeping the temperature and reacting for 2h, after the reaction is finished, washing with water to be neutral, then decompressing and desolventizing to 200 ℃, controlling the vacuum degree to be more than-0.09 Mpa to obtain o-cresol formaldehyde epoxy resin, and cooling to obtain 1650kg of yellow solid resin.

Comparative example 2

Adding 1000kg of preheated and melted o-cresol into a high-position metering tank by using a special pump, metering and adding the o-cresol into a reaction kettle, then adding 236kg of paraformaldehyde and 200kg of oxalic acid, heating to 100 ℃, carrying out heat preservation reaction for 6 hours, dehydrating to 160 ℃ under normal pressure after the reaction is finished, then carrying out dephenolization and desolvation under reduced pressure, keeping the vacuum degree at more than-0.09 Mpa, stopping the reaction after the reaction lasts for 2 hours after the reaction is finished to 195 ℃, then cooling to normal temperature, adding 4283.75kg of epoxy chloropropane, 21.25kg of benzyltriethylammonium chloride, heating to 90 ℃, carrying out heat preservation reaction for 4 hours, cooling to 70 ℃ after the reaction is finished, then adding 24.7kg of caustic soda flakes every 12 minutes, finishing the addition of 2h, continuing the heat preservation reaction for 1.5 hours, carrying out the reaction and carrying out the vacuum dephenolization and desoxychloropropane at 160 ℃ under reduced pressure until the vacuum degree is more than-0.08 Mpa; then adding 800kg of MIBK and 400kg of deionized water, stirring for 10min, standing and draining; then adding NaOH (15%), heating to 85 ℃, keeping the temperature for 2h, after the reaction is finished, washing with water to be neutral, then removing the solvent under reduced pressure to 200 ℃ and keeping the vacuum degree above-0.09 Mpa to obtain the o-cresol formaldehyde epoxy resin, heating to 75 ℃ after the epoxy resin is cooled to normal temperature, adding 420kg of acrylic acid in a dropwise adding mode for 1h, adding 8kg of N, N-dimethylaniline, and cooling to obtain 1850kg of yellow solid resin.

The yellow transparent resins obtained in examples 1 to 4 of the present application (i.e., o-cresol novolac-modified with acrylic acid and resorcinol) and the solid resins obtained in comparative examples 1 to 2 were subjected to the following performance tests, and the results are shown in table 1:

TABLE 1 Performance testing of the o-cresol-formaldehyde epoxy resins of examples 1 to 4 and comparative examples 1 to 2

Resin composition	Softening point/. Degree.C	Speed of convergence/s	viscosity/P	Free phenol/%)	Molecular weight
						Example 1	85	60	2.556	1.3	Mn＝885，Mw＝5447
Example 2	89	65	2.416	1.1	Mn＝865，Mw＝5765
						Example 3	86	66	2.455	1.2	Mn＝893，Mw＝5563
Example 4	88	59	2.488	1.5	Mn＝875，Mw＝5561
						Comparative example 1	94	55	1.356	1.4	Mn＝705，Mw＝1760
Comparative example 2	92	53	1.001	1.4	Mn＝785，Mw＝2856

As can be seen from Table 1, the softening point of the resin is reduced to a certain extent, and Mw and Mn of the acrylic acid and resorcinol modified o-cresol formaldehyde epoxy resin adopted in the invention are higher than those of the physically mixed resin, because the epoxy resin is successfully introduced with conjugated carbonyl groups, the proportion of the high molecular weight resin in the resin system is increased, and the viscosity is increased, which shows that resorcinol successfully improves the adhesive force of the resin.

And coating the modified novolac epoxy resin, a curing agent crosslinking agent (maleic anhydride), a photosensitizer and the like on the epoxy resin base plate coated with the copper film by adopting a screen printing mode. Exposing on an exposure instrument for a designed time, measuring the adhesive force, or thermally curing in a constant temperature box (at the temperature of 150 ℃ for 1 h) after ultraviolet exposure, and measuring the adhesive force.

TABLE 2 results of photochemical Activity test of the resins

Resin composition	Exposure time/s	Exposure time/s	Exposure time/s	Exposure time/s
					Example 1	59.55	66.22	69.36	75.08
Example 2	59.23	66.13	69.30	75.08
					Example 3	59.43	66.20	69.34	75.07
Example 4	59.17	65.99	69.28	75.05
					Comparative example 1	21.35	30.63	39.32	48.95
Comparative example 2	58.35	65.43	69.02	75.10

TABLE 3 resin adhesion test results

Resin composition	Adhesion/rating after UV illumination	Adhesion/grade
			Example 1	1	1
Example 2	1	1
			Example 3	1	1
Example 4	1	1
			Comparative example 1	3	2
Comparative example 2	3	2

As can be seen from tables 2 and 3, the photochemical activity and the adhesion of the acrylic acid and resorcinol modified o-cresol formaldehyde epoxy resin of the present application are higher than those of the non-modified resin in the examples 1 to 4, which are higher than those of the comparative examples 1 and 2.

The following test was conducted on a tan transparent resin (modified with an acrylic acid and resorcinol-modified o-cresol formaldehyde epoxy resin) obtained in example 1 of the present application, a solid resin obtained in comparative examples 1 to 2, and a thermogravimetric test in which the resin of example 1 was crosslinked and cured at 250 ℃ for 2 hours by adding 3% dodecylbenzene sulfonic acid. The resins of comparative examples 1 to 2 were crosslinked and cured by adding 5% tropine. The test results are shown in table 4:

TABLE 4 thermal weight loss test of phenolic resins of examples and comparative examples

Phenolic resin	300 ℃ residual ratio/%)	Residual ratio at 600 ℃/%)
			Example 1	92.3	54.8
Comparative example 1	88.1	50.5
			Comparative example 2	89.6	51.1

As can be seen from Table 4, the acrylic and resorcinol-modified o-cresol novolac epoxy resins of the present application, example 1, have higher high-temperature stability than comparative examples 1 and 2, which shows that the acrylic and resorcinol-modified o-cresol novolac epoxy resins of the present application have higher heat resistance than the unmodified novolac epoxy resins.

In practical application, the modified resin is used for electronic packaging, and can bear higher temperature and have stronger durability; when the paint is used for a paint film, the paint can not be crosslinked and cured in the painting process after being prepared into the paint, and can be cured immediately after being painted by illumination, so that the painted samples can be mutually overlapped immediately after being subjected to light treatment, thereby simplifying the production process and saving the storage space.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the patent. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims (10)

1. The preparation method of the modified o-cresol formaldehyde epoxy resin is characterized by comprising the following steps:

s10, reacting acrylic acid and resorcinol under the action of a catalyst I to generate a product A, and reacting o-cresol and paraformaldehyde under the action of a catalyst II to generate a product B;

s20, mixing and reacting the product B with the product A to obtain a product C;

s30, reacting the product C with epoxy chloropropane under the action of a catalyst III to generate a product D;

and S40, carrying out ring-closure reaction on the product D and an alkali solution to generate the modified o-cresol formaldehyde epoxy resin.

2. The preparation method of the modified o-cresol formaldehyde epoxy resin as claimed in claim 1, wherein the catalyst I is at least one of sodium ethoxide, sodium hydride and sodium amide;

the catalyst II is at least one of oxalic acid, acetic acid and p-toluenesulfonic acid;

the catalyst III is a quaternary ammonium salt catalyst;

the alkali solution is sodium hydroxide solution.

3. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 1, wherein the steps S10 to S40 are all performed in a microchannel reactor.

4. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 3, wherein the microchannel reactor comprises:

a container I, wherein the reaction of the acrylic acid and the resorcinol in the step S10 is carried out in the container I, the reaction temperature is 110-120 ℃, and the reaction time is 3-5min;

a container II, wherein the o-cresol and the paraformaldehyde in the step S10 are carried out in the container II, the reaction temperature is 90-110 ℃, and the reaction time is 8-10min;

a container III, wherein the step S20 is carried out in the container III, the reaction temperature is 90-110 ℃, and the reaction time is 2-4min;

a container IV, wherein the step S30 is carried out in the container IV, the reaction temperature is 85-95 ℃, and the reaction time is 4-6min;

and (5) a vessel V, wherein the step S40 is carried out in the vessel V, the reaction temperature is 60-70 ℃, and the reaction time is 1-2min.

5. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 1, wherein in the step S10, the molar ratio of the acrylic acid to the resorcinol is 1:2-4;

the catalyst I accounts for 0.5-2% of the mass of the acrylic acid;

in the step S10, the molar ratio of the paraformaldehyde to the o-cresol is 1.75-0.95;

the catalyst II accounts for 2-4% of the mass of the o-cresol.

6. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 1, wherein the mass ratio of the product A in the step S20 to the o-cresol in the step S10 is 0.5-1.

7. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 1, wherein the molar ratio of the epichlorohydrin in the step S30 to the product A in the step S20 is 4 to 8;

the molar ratio of the catalyst III to the product A in step S20 is 0.01-0.03.

8. The method for preparing the modified o-cresol formaldehyde epoxy resin according to claim 1, wherein the molar ratio of the alkali in the alkali solution in the step S40 to the product B in the step S20 is 3-5.

9. The preparation method of the modified o-cresol formaldehyde epoxy resin as claimed in claim 1, further comprising the step of refining, wherein the refining comprises the following specific steps:

removing the epoxy chloropropane reacted in the step S40, and cleaning by using a solvent;

adding an alkali solution for reaction;

and after the reaction is finished, sequentially washing with water to be neutral, and removing the solvent to obtain the modified o-cresol formaldehyde epoxy resin.

10. The modified o-cresol formaldehyde epoxy resin prepared by the preparation method of any one of claims 1 to 9.

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