High-temperature-resistant foaming agent and preparation method thereof

Abstract

The invention relates to the technical field of foaming agents, and discloses a high-temperature-resistant foaming agent and a preparation method thereof. The high-temperature-resistant foaming agent is obtained by adding sulphobetaine modified benzoxazine, melamine benzene sulfonate modified polyoxyethylene ether, lauryl sodium sulfate and a polyvinyl alcohol foam stabilizer into water, stirring and mixing. The benzoxazine structure has relatively high rigidity and stability at a high temperature; sulfobetaine is an ampholytic surfactant and has high foaming capacity, sulfonic acid groups are high in temperature resistance, and the foaming performance and the high temperature resistance of the foaming agent are improved; melamine molecules are not easy to decompose at high temperature, so that the high temperature resistance of the foaming agent is improved; polyoxyethylene ether is a nonionic surfactant and has remarkable surface activity, the sulfonic acid group anions and the polyoxyethylene ether nonionic surfactant play a synergistic role, mixed micelles are formed in an aqueous solution, and the foaming performance of the foaming agent is improved.

Description

Technical Field

[0001] The invention relates to the technical field of foaming agents, in particular to a high temperature resistant foaming agent and a preparation method thereof. Background Art

[0002] Heavy oil is difficult to develop and has high recovery costs. Generally, after heavy oil is exploited by steam drive, there are still a large number of oil resources in the reservoir that are difficult to recover. In view of this situation, many oil fields have begun to adopt foam flooding technology. Foam flooding technology is an oil recovery method that uses foam formed by mixing water, gas and foaming agent as an oil displacement agent. This technology combines the advantages of gas and foam, and significantly improves the recovery rate of oil by increasing the swept volume and reducing the pumping cost. At present, the foaming agents commonly used in oil fields have poor high temperature resistance and weak foaming ability in high-concentration brine. Therefore, it is of great significance to improve the high temperature resistance of foaming agents. In the document "Synthesis and Performance Evaluation of Gemini Quaternary Ammonium Salt Foaming Agent", a gemini quaternary ammonium salt foaming agent is synthesized by quaternization reaction using tetradecane chloride and tetramethylethylenediamine as raw materials, which has the advantages of high yield, high purity and good foaming performance, but its high temperature resistance effect needs to be enhanced. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a high temperature resistant foaming agent and a preparation method thereof. The foaming agent prepared by the present invention has good high temperature resistance and foaming performance.

[0004] (II) Technical solution To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a high temperature resistant foaming agent, comprising the following components by weight: 16-22 parts by weight of sulfobetaine modified benzoxazine, 23-27 parts by weight of melamine benzene sulfonate modified polyoxyethylene ether, 7-10 parts by weight of sodium lauryl sulfate, 2-4 parts by weight of polyvinyl alcohol foam stabilizer, and 35-45 parts by weight of water.

[0005] Preferably, the method for preparing the sulfobetaine-modified benzoxazine comprises the following steps: (1) Add 13-17 g of 4-dimethylaminophenol, 12-16 g of 3-(2-naphthyl)aniline, and 24-32 g of paraformaldehyde to a dioxane solvent, stir and mix, and heat to react for 4-5 hours. After the reaction is completed, filter, wash, and dry to obtain a tertiary aminobenzoxazine; (2) Add deionized water and 3-5 g of sodium bisulfite to the reactor, stir during the heating process to dissolve the sodium bisulfite, and when the temperature rises to 72-78°C, dropwise add 10-15 g of 1,2-epoxychlorobutane for 1.5-2 h. After the addition is complete, heat to 84-88°C and react for 2-4 h. After the reaction is complete, cool in an ice-water bath, filter the precipitated crystals after cooling, and recrystallize to obtain intermediate 1; (3) Deionized water and 6-9 g of intermediate 1 are added to the reactor, and condensation reflux and stirring are performed during the heating process. After the intermediate 1 is dissolved, 8-10 g of tertiary aminobenzoxazine and 0.05-0.07 g of catalyst are added, and the temperature is raised to 90-95° C. and the reaction is carried out for 6-8 h. After the reaction is completed, the reaction is washed and dried to obtain sulfobetaine-modified benzoxazine.

[0006] Preferably, the reaction temperature in step (1) is 100-110°C.

[0007] Preferably, the catalyst in step (3) is sodium ethoxide.

[0008] Preferably, the preparation method of the melamine benzene sulfonate modified polyoxyethylene ether comprises the following steps: S1. Add melamine to deionized water, stir to dissolve, heat to 88-92°C, dissolve p-mercaptobenzenesulfonic acid in deionized water, and then add it dropwise to the melamine solution to react for 1.5-2.5h. After the reaction is completed, cool naturally, vacuum filter, wash and dry to obtain melamine benzenesulfonate; S2. Add 13-17 g of 5-hexenyl-1-ol and 7-10 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.04-0.08 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 40-45 ° C, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; S3. Add 15-18g of intermediate 2 and 0.06-0.08g of catalyst into the autoclave, heat it to 80-85°C, start stirring and evacuate, after nitrogen replacement, heat it to 155-165°C, add 2-5g of ethylene oxide, start induction reaction, and when the pressure drops to 0.1-0.14MPa, continuously add 10-14g of ethylene oxide to make the system ethylene oxide pressure constant. After the ethylene oxide feeding is completed, cool it to 78-82°C, remove the ethylene oxide gas in the reaction system under vacuum, and obtain melamine benzene sulfonate modified polyoxyethylene ether.

[0009] Preferably, the mass ratio of melamine to p-mercaptobenzenesulfonic acid in S1 is 1:1.08-1.14.

[0010] Preferably, the ultraviolet light irradiation time in S2 is 2.5-4h.

[0011] Preferably, the catalyst in S3 is potassium hydroxide.

[0012] Preferably, the preparation method of the high temperature resistant foaming agent is: adding sulfobetaine modified benzoxazine, melamine benzene sulfonate modified polyoxyethylene ether, sodium lauryl sulfate, and polyvinyl alcohol foam stabilizer into water, stirring and mixing at 52-60° C. to obtain the high temperature resistant foaming agent.

[0013] 3. Beneficial technical effects The invention obtains a high temperature resistant foaming agent by adding sulfobetaine modified benzoxazine, melamine benzene sulfonate modified polyoxyethylene ether, sodium lauryl sulfate and polyvinyl alcohol foam stabilizer into water, stirring and mixing.

[0014] 4-Dimethylaminophenol, 3-(2-naphthyl)aniline and polyformaldehyde undergo Mannich condensation reaction to obtain tertiary aminobenzoxazine, sodium bisulfite and 1,2-epoxychlorobutane undergo ring-opening addition reaction to obtain intermediate 1, and the chlorine in intermediate 1 reacts with the tertiary amine in the tertiary aminobenzoxazine to obtain sulfobetaine-modified benzoxazine. The amino group in melamine reacts with the sulfonic acid group in p-mercaptobenzenesulfonic acid to obtain melamine benzenesulfonate, and the mercapto group in melamine benzenesulfonate undergoes click reaction with 5-hexenyl-1-ol to obtain intermediate 2 and introduce hydroxyl group, and intermediate 2 and ethylene oxide are polymerized at high temperature to obtain melamine benzenesulfonate-modified polyoxyethylene ether.

[0015] In sulfobetaine-modified benzoxazine, benzoxazine is composed of two benzene rings connected by an oxazine ring. This structure makes the foaming agent have high rigidity and stability at high temperatures. Sulfobetaine is a zwitterionic surfactant with sulfonic acid groups and cations, which has strong foaming ability, and the sulfonic acid groups it contains have strong temperature resistance, which improves the foaming performance and high temperature resistance of the foaming agent. In melamine benzenesulfonate-modified polyoxyethylene ether, the melamine molecule contains multiple carbon-nitrogen bonds and carbon-carbon bonds. These covalent bonds have high bond energy, making the molecule difficult to decompose at high temperatures, thereby The high temperature resistance of the foaming agent is improved; polyoxyethylene ether is a non-ionic surfactant with significant surface activity. It can be adsorbed on the interface of water and air and significantly reduce the surface tension of the interface. When the surface tension is reduced, the energy required to form foam is reduced, thereby improving the foaming ability of the foaming agent; the sulfonic acid anion and the polyoxyethylene ether non-ionic surfactant play a synergistic role, thereby making it easier to form foam, and mixed micelles can be formed in the aqueous solution. These mixed micelles are more stable than the micelles formed by a single surfactant, thereby further improving the foaming performance of the foaming agent. DETAILED DESCRIPTION Example 1

[0016] (1) Add 13 g of 4-dimethylaminophenol, 12 g of 3-(2-naphthyl)aniline and 24 g of polyformaldehyde to a dioxane solvent, stir and mix, heat to 100° C. and react for 4 h. After the reaction is completed, filter, wash and dry to obtain a tertiary aminobenzoxazine; (2) Deionized water and 3 g of sodium bisulfite were added to the reactor. The temperature was stirred during the heating process to dissolve the sodium bisulfite. When the temperature rose to 72°C, 10 g of 1,2-epoxychlorobutane was added dropwise for 1.5 h. After the addition was completed, the temperature was raised to 84°C and the reaction was continued for 2 h. After the reaction was completed, the reactor was cooled in an ice-water bath. The crystals precipitated after cooling were filtered and recrystallized to obtain intermediate 1. (3) Deionized water and 6 g of intermediate 1 were added to the reactor, and condensation reflux and stirring were performed during the heating process. After the intermediate 1 was dissolved, 8 g of tertiary aminobenzoxazine and 0.05 g of sodium ethoxide catalyst were added, and the temperature was raised to 90° C. and reacted for 6 h. After the reaction was completed, the reaction was washed and dried to obtain sulfobetaine-modified benzoxazine; (4) adding melamine to deionized water, stirring to dissolve, heating to 88° C., dissolving p-mercaptobenzenesulfonic acid in deionized water, and then dropping it into the melamine solution, wherein the mass ratio of melamine to p-mercaptobenzenesulfonic acid is 1:1.08, reacting for 1.5 h. After the reaction is completed, naturally cooling, vacuum filtering, washing and drying to obtain melamine benzenesulfonate; (5) Add 13 g of 5-hexenyl-1-ol and 7 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.04 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 40 ° C for 2.5 h, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; (6) 15 g of intermediate 2 and 0.06 g of potassium hydroxide catalyst were added to the autoclave, the temperature was raised to 80°C, stirring was started and vacuum was applied. After nitrogen replacement, the temperature was raised to 155°C, 2 g of ethylene oxide was added, and the induction reaction was started. When the pressure dropped to 0.1 MPa, 10 g of ethylene oxide was continuously added to make the system ethylene oxide pressure constant. After the ethylene oxide feeding was completed, the autoclave was cooled to 78°C, and the ethylene oxide gas in the reaction system was removed under vacuum to obtain melamine benzene sulfonate modified polyoxyethylene ether; (7) 16 parts by weight of sulfobetaine-modified benzoxazine, 23 parts by weight of melamine benzenesulfonate-modified polyoxyethylene ether, 7 parts by weight of sodium lauryl sulfate, and 2 parts by weight of polyvinyl alcohol foam stabilizer were added to 35 parts by weight of water, and the mixture was stirred at 52° C. to obtain a high temperature resistant foaming agent. Example 2

[0017] (1) Add 17 g of 4-dimethylaminophenol, 16 g of 3-(2-naphthyl)aniline and 32 g of polyformaldehyde to a dioxane solvent, stir and mix, heat to 110° C. and react for 5 h. After the reaction is completed, filter, wash and dry to obtain a tertiary aminobenzoxazine; (2) Deionized water and 5 g of sodium bisulfite were added to the reactor. The temperature was stirred during the heating process to dissolve the sodium bisulfite. When the temperature rose to 78°C, 15 g of 1,2-epoxychlorobutane was added dropwise for 2 h. After the addition was completed, the temperature was raised to 88°C and the reaction was continued for 4 h. After the reaction was completed, the reactor was cooled in an ice-water bath. The crystals precipitated after cooling were filtered and recrystallized to obtain intermediate 1. (3) Deionized water and 9 g of intermediate 1 were added to the reactor, and condensation reflux and stirring were performed during the heating process. After the intermediate 1 was dissolved, 10 g of tertiary aminobenzoxazine and 0.07 g of sodium ethoxide catalyst were added, and the temperature was raised to 95° C. and reacted for 8 h. After the reaction was completed, the reaction was washed and dried to obtain sulfobetaine-modified benzoxazine; (4) adding melamine to deionized water, stirring to dissolve, heating to 92° C., dissolving p-mercaptobenzenesulfonic acid in deionized water, and then dropping it into the melamine solution, wherein the mass ratio of melamine to p-mercaptobenzenesulfonic acid is 1:1.14, reacting for 2.5 hours. After the reaction is completed, naturally cooling, vacuum filtering, washing and drying to obtain melamine benzenesulfonate; (5) Add 17 g of 5-hexenyl-1-ol and 10 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.08 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 45 ° C for 4 h, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; (6) 18 g of intermediate 2 and 0.08 g of potassium hydroxide catalyst were added to the autoclave, the temperature was raised to 85°C, stirring was started and vacuum was applied. After nitrogen replacement, the temperature was raised to 165°C, 5 g of ethylene oxide was added, and the induction reaction was started. When the pressure dropped to 0.14 MPa, 14 g of ethylene oxide was continuously added to make the system ethylene oxide pressure constant. After the ethylene oxide feeding was completed, the autoclave was cooled to 82°C, and the ethylene oxide gas in the reaction system was removed under vacuum to obtain melamine benzene sulfonate modified polyoxyethylene ether; (7) 22 parts by weight of sulfobetaine-modified benzoxazine, 27 parts by weight of melamine benzenesulfonate-modified polyoxyethylene ether, 10 parts by weight of sodium lauryl sulfate, and 4 parts by weight of polyvinyl alcohol foam stabilizer were added to 45 parts by weight of water, and the mixture was stirred at 60° C. to obtain a high temperature resistant foaming agent. Example 3

[0018] (1) Add 15 g of 4-dimethylaminophenol, 14 g of 3-(2-naphthyl)aniline and 28 g of polyformaldehyde to a dioxane solvent, stir and mix, heat to 105° C. and react for 4.5 h. After the reaction is completed, filter, wash and dry to obtain a tertiary aminobenzoxazine; (2) Deionized water and 4 g of sodium bisulfite were added to the reactor. The temperature was stirred during the heating process to dissolve the sodium bisulfite. When the temperature reached 75°C, 12.5 g of 1,2-epoxychlorobutane was added dropwise for 1.8 h. After the addition was completed, the temperature was raised to 86°C and the reaction was continued for 3 h. After the reaction was completed, the reactor was cooled in an ice-water bath. The crystals precipitated after cooling were filtered and recrystallized to obtain intermediate 1. (3) Deionized water and 7.5 g of intermediate 1 were added to the reactor, and condensation reflux and stirring were performed during the heating process. After the intermediate 1 was dissolved, 9 g of tertiary aminobenzoxazine and 0.06 g of sodium ethoxide catalyst were added, and the temperature was raised to 92° C. and the reaction was carried out for 7 h. After the reaction was completed, the reaction was washed and dried to obtain sulfobetaine-modified benzoxazine; (4) adding melamine to deionized water, stirring to dissolve, heating to 90° C., dissolving p-mercaptobenzenesulfonic acid in deionized water, and then dropping it into the melamine solution, wherein the mass ratio of melamine to p-mercaptobenzenesulfonic acid is 1:1.11, reacting for 2 h. After the reaction is completed, naturally cooling, vacuum filtering, washing and drying to obtain melamine benzenesulfonate; (5) Add 15 g of 5-hexenyl-1-ol and 8.5 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.06 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 42 ° C for 3.2 h, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; (6) 16.5 g of intermediate 2 and 0.07 g of potassium hydroxide catalyst were added to the autoclave, the temperature was raised to 82° C., stirring was started and vacuum was applied. After nitrogen replacement, the temperature was raised to 160° C., 3.5 g of ethylene oxide was added, and the induction reaction was started. When the pressure dropped to 0.12 MPa, 12 g of ethylene oxide was continuously added to make the system ethylene oxide pressure constant. After the ethylene oxide feeding was completed, the autoclave was cooled to 80° C. The ethylene oxide gas in the reaction system was removed under vacuum to obtain melamine benzene sulfonate modified polyoxyethylene ether; (7) 19 parts by weight of sulfobetaine-modified benzoxazine, 25 parts by weight of melamine benzenesulfonate-modified polyoxyethylene ether, 8 parts by weight of sodium lauryl sulfate, and 3 parts by weight of polyvinyl alcohol foam stabilizer were added to 40 parts by weight of water, and the mixture was stirred at 56° C. to obtain a high temperature resistant foaming agent. Example 4

[0019] (1) Add 13 g of 4-dimethylaminophenol, 12 g of 3-(2-naphthyl)aniline and 24 g of polyformaldehyde to a dioxane solvent, stir and mix, heat to 100° C. and react for 4 h. After the reaction is completed, filter, wash and dry to obtain a tertiary aminobenzoxazine; (2) Deionized water and 3 g of sodium bisulfite were added to the reactor. The temperature was stirred during the heating process to dissolve the sodium bisulfite. When the temperature rose to 72°C, 10 g of 1,2-epoxychlorobutane was added dropwise for 1.5 h. After the addition was completed, the temperature was raised to 84°C and the reaction was continued for 2 h. After the reaction was completed, the reactor was cooled in an ice-water bath. The crystals precipitated after cooling were filtered and recrystallized to obtain intermediate 1. (3) Deionized water and 6 g of intermediate 1 were added to the reactor, and condensation reflux and stirring were performed during the heating process. After the intermediate 1 was dissolved, 8 g of tertiary aminobenzoxazine and 0.05 g of sodium ethoxide catalyst were added, and the temperature was raised to 90° C. and reacted for 6 h. After the reaction was completed, the reaction was washed and dried to obtain sulfobetaine-modified benzoxazine; (4) adding melamine to deionized water, stirring to dissolve, heating to 92° C., dissolving p-mercaptobenzenesulfonic acid in deionized water, and then dropping it into the melamine solution, wherein the mass ratio of melamine to p-mercaptobenzenesulfonic acid is 1:1.14, reacting for 2.5 hours. After the reaction is completed, naturally cooling, vacuum filtering, washing and drying to obtain melamine benzenesulfonate; (5) Add 17 g of 5-hexenyl-1-ol and 10 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.08 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 45 ° C for 4 h, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; (6) 16.5 g of intermediate 2 and 0.07 g of potassium hydroxide catalyst were added to the autoclave, the temperature was raised to 82° C., stirring was started and vacuum was applied. After nitrogen replacement, the temperature was raised to 160° C., 3.5 g of ethylene oxide was added, and the induction reaction was started. When the pressure dropped to 0.12 MPa, 12 g of ethylene oxide was continuously added to make the system ethylene oxide pressure constant. After the ethylene oxide feeding was completed, the autoclave was cooled to 80° C. The ethylene oxide gas in the reaction system was removed under vacuum to obtain melamine benzene sulfonate modified polyoxyethylene ether; (7) 19 parts by weight of sulfobetaine-modified benzoxazine, 25 parts by weight of melamine benzenesulfonate-modified polyoxyethylene ether, 8 parts by weight of sodium lauryl sulfate, and 3 parts by weight of polyvinyl alcohol foam stabilizer were added to 40 parts by weight of water, and the mixture was stirred at 56° C. to obtain a high temperature resistant foaming agent. Example 5

[0020] (1) Add 15 g of 4-dimethylaminophenol, 14 g of 3-(2-naphthyl)aniline and 28 g of polyformaldehyde to a dioxane solvent, stir and mix, heat to 105° C. and react for 4.5 h. After the reaction is completed, filter, wash and dry to obtain a tertiary aminobenzoxazine; (2) Deionized water and 4 g of sodium bisulfite were added to the reactor. The temperature was stirred during the heating process to dissolve the sodium bisulfite. When the temperature reached 75°C, 12.5 g of 1,2-epoxychlorobutane was added dropwise for 1.8 h. After the addition was completed, the temperature was raised to 86°C and the reaction was continued for 3 h. After the reaction was completed, the reactor was cooled in an ice-water bath. The crystals precipitated after cooling were filtered and recrystallized to obtain intermediate 1. (3) Deionized water and 7.5 g of intermediate 1 were added to the reactor, and condensation reflux and stirring were performed during the heating process. After the intermediate 1 was dissolved, 9 g of tertiary aminobenzoxazine and 0.06 g of sodium ethoxide catalyst were added, and the temperature was raised to 92° C. and the reaction was carried out for 7 h. After the reaction was completed, the reaction was washed and dried to obtain sulfobetaine-modified benzoxazine; (4) adding melamine to deionized water, stirring to dissolve, heating to 88° C., dissolving p-mercaptobenzenesulfonic acid in deionized water, and then dropping it into the melamine solution, wherein the mass ratio of melamine to p-mercaptobenzenesulfonic acid is 1:1.08, reacting for 1.5 h. After the reaction is completed, naturally cooling, vacuum filtering, washing and drying to obtain melamine benzenesulfonate; (5) Add 13 g of 5-hexenyl-1-ol and 7 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.04 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 40 ° C for 2.5 h, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; (6) 18 g of intermediate 2 and 0.08 g of potassium hydroxide catalyst were added to the autoclave, the temperature was raised to 85°C, stirring was started and vacuum was applied. After nitrogen replacement, the temperature was raised to 165°C, 5 g of ethylene oxide was added, and the induction reaction was started. When the pressure dropped to 0.14 MPa, 14 g of ethylene oxide was continuously added to make the system ethylene oxide pressure constant. After the ethylene oxide feeding was completed, the autoclave was cooled to 82°C, and the ethylene oxide gas in the reaction system was removed under vacuum to obtain melamine benzene sulfonate modified polyoxyethylene ether; (7) 22 parts by weight of sulfobetaine-modified benzoxazine, 27 parts by weight of melamine benzenesulfonate-modified polyoxyethylene ether, 10 parts by weight of sodium lauryl sulfate, and 4 parts by weight of polyvinyl alcohol foam stabilizer were added to 45 parts by weight of water, and the mixture was stirred at 60° C. to obtain a high temperature resistant foaming agent.

[0021] Comparative Example 1 Compared with Example 5, this comparative example is different in that no sulfobetaine-modified benzoxazine is added.

[0022] Comparative Example 2 Compared with Example 5, the difference in this comparative example is that no melamine benzene sulfonate-modified polyoxyethylene ether is added.

[0023] Add 0.5% frother to the total mineralization of 100000mg / L, Ca 2+ In simulated formation water with a content of 12000 mg / L, at different temperatures, the foam volume and foam half-life of the foaming agent in Examples 1-5 and Comparative Examples 1-2 were tested using the Waring-Blender method. The test results are shown in Tables 1 and 2.

[0024] Table 1: Foam volume test.

[0025]

[0026] Table 2: Foam half-life testing.

[0027]

[0028] It can be seen from Table 1 and Table 2 that compared with Comparative Examples 1-2, the foaming agent of Examples 1-5 can still maintain a larger foam volume and a longer half-life at high temperatures, and has a better high temperature resistance effect.

[0029] According to Q / SH0269-2009 "Evaluation Method for Performance of Foaming Agents for Oil Displacement", the resistance factor test was performed on the foaming agents in Examples 1-5 and Comparative Examples 1-2. The test temperature was 300° C. The test results are shown in Table 3.

[0030] Table 3: Resistance factor test.

[0031]

[0032] As can be seen from Table 3, compared with Comparative Examples 1-2, Examples 1-5 have a larger resistance factor of the foaming agent at high temperature and have better foaming ability.

[0033] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high temperature resistant foaming agent, characterized in that: The invention comprises the following components by weight: 16-22 parts by weight of sulfobetaine modified benzoxazine, 23-27 parts by weight of melamine benzenesulfonate modified polyoxyethylene ether, 7-10 parts by weight of sodium lauryl sulfate, 2-4 parts by weight of polyvinyl alcohol foam stabilizer and 35-45 parts by weight of water.

2. The high temperature resistant foaming agent according to claim 1, characterized in that: The method for preparing the sulfobetaine-modified benzoxazine comprises the following steps: (1) Add 13-17 g of 4-dimethylaminophenol, 12-16 g of 3-(2-naphthyl)aniline, and 24-32 g of paraformaldehyde to a dioxane solvent, stir and mix, and heat to react for 4-5 hours. After the reaction is completed, filter, wash, and dry to obtain a tertiary aminobenzoxazine; (2) Add deionized water and 3-5 g of sodium bisulfite to the reactor, stir during the heating process to dissolve the sodium bisulfite, and when the temperature rises to 72-78°C, dropwise add 10-15 g of 1,2-epoxychlorobutane for 1.5-2 h. After the addition is complete, heat to 84-88°C and react for 2-4 h. After the reaction is complete, cool in an ice-water bath, filter the precipitated crystals after cooling, and recrystallize to obtain intermediate 1; (3) Deionized water and 6-9 g of intermediate 1 are added to the reactor, and condensation reflux and stirring are performed during the heating process. After the intermediate 1 is dissolved, 8-10 g of tertiary aminobenzoxazine and 0.05-0.07 g of catalyst are added, and the temperature is raised to 90-95° C. and the reaction is carried out for 6-8 h. After the reaction is completed, the reaction is washed and dried to obtain sulfobetaine-modified benzoxazine.

3. The high temperature resistant foaming agent according to claim 2, characterized in that: The reaction temperature in step (1) is 100-110°C.

4. The high temperature resistant foaming agent according to claim 2, characterized in that: The catalyst in step (3) is sodium ethoxide.

5. The high temperature resistant foaming agent according to claim 1, characterized in that: The preparation method of melamine benzene sulfonate modified polyoxyethylene ether comprises the following steps: S1. Add melamine to deionized water, stir to dissolve, heat to 88-92°C, dissolve p-mercaptobenzenesulfonic acid in deionized water, and then add it dropwise to the melamine solution to react for 1.5-2.5h. After the reaction is completed, cool naturally, vacuum filter, wash and dry to obtain melamine benzenesulfonate; S2. Add 13-17 g of 5-hexenyl-1-ol and 7-10 g of melamine sulfonate to N,N-dimethylformamide solvent, stir and mix, then add 0.04-0.08 g of benzoin dimethyl ether photoinitiator, irradiate with 365 nm ultraviolet light at 40-45 ° C, after the reaction is completed, centrifuge, wash and dry to obtain intermediate 2; S3. Add 15-18g of intermediate 2 and 0.06-0.08g of catalyst into the autoclave, heat it to 80-85°C, start stirring and evacuate, after nitrogen replacement, heat it to 155-165°C, add 2-5g of ethylene oxide, start induction reaction, and when the pressure drops to 0.1-0.14MPa, continuously add 10-14g of ethylene oxide to make the system ethylene oxide pressure constant. After the ethylene oxide feeding is completed, cool it to 78-82°C, remove the ethylene oxide gas in the reaction system under vacuum, and obtain melamine benzene sulfonate modified polyoxyethylene ether.

6. The high temperature resistant foaming agent according to claim 5, characterized in that: The mass ratio of melamine to p-mercaptobenzenesulfonic acid in S1 is 1:1.08-1.

14.

7. The high temperature resistant foaming agent according to claim 5, characterized in that: The ultraviolet light irradiation time in S2 is 2.5-4h.

8. The high temperature resistant foaming agent according to claim 5, characterized in that: The catalyst in S3 is potassium hydroxide.

9. A method for preparing a high temperature resistant foaming agent according to any one of claims 1 to 8, characterized in that: The preparation method of the high temperature resistant foaming agent comprises the following steps: adding sulfobetaine modified benzoxazine, melamine benzene sulfonate modified polyoxyethylene ether, sodium lauryl sulfate and polyvinyl alcohol foam stabilizer into water, stirring and mixing at 52-60° C. to obtain the high temperature resistant foaming agent.

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