An anticorrosive phenolic epoxy resin coating for oil pipes and a preparation method thereof

Abstract

The application relates to the technical field of anticorrosive coatings, and discloses an anticorrosive phenolic aldehyde epoxy resin coating for oil pipes and a preparation method thereof, which comprises 100 parts by weight of phenolic aldehyde epoxy resin, 18-30 parts by weight of a curing agent and 5-15 parts by weight of amino rosin modified graphene; the amino rosin acid ester structure is grafted on the surface of graphene oxide, the interface compatibility between the graphene and the phenolic aldehyde epoxy resin is improved, the dispersibility of the graphene in the coating is improved, the hardness, salt mist resistance, water resistance and corrosion resistance of the coating film are improved, the uniformly dispersed graphene also has a good improvement effect on the heat resistance of the coating film. Moreover, the amino rosin acid ester contains active amino groups, can form a co-curing system with polyether amine D230 and the like, and can be used for curing reaction of the phenolic aldehyde epoxy resin, so that the hardness, hot water resistance and thermal weight loss temperature of the coating film are improved.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to an anti-corrosion phenolic epoxy resin coating for oil pipelines and its preparation method. Background Technology

[0002] Anti-corrosion coatings are widely used in petrochemicals, pipeline transportation, instrumentation, and construction. They mainly include epoxy resin coatings and acrylic resin coatings. Phenolic epoxy resin, a linear phenolic polyglycidyl ether epoxy resin, possesses excellent abrasion resistance, chemical resistance, and curing properties, and is primarily used in mud tanks, sewage tanks, and the inner walls of storage tanks on offshore oil platforms. Developing high-performance, heat-resistant, water-resistant, and corrosion-resistant phenolic epoxy resins is of great significance.

[0003] Rosin acid is a class of natural compounds containing a tricyclic diterpene fused-ring structure. It is inexpensive, readily available, and environmentally friendly, and is widely used in coatings, plastics, rubber, and other materials. Graphene oxide possesses high mechanical strength, excellent high-temperature resistance, and good electrical conductivity; its addition to coatings can improve their heat resistance and salt spray resistance. Surface modification of graphene oxide to improve its dispersibility is a research hotspot. Patent CN116082928A discloses an anti-corrosion coating prepared using rosin-modified o-cresyl aldehyde epoxy resin-based vinyl ester resin, quartz sand, epoxy reactive diluent, and polyaniline-modified graphene as raw materials, exhibiting good anti-corrosion performance and impact resistance. However, this patent does not improve the coating's heat resistance, water resistance, or other properties. Summary of the Invention

[0004] The technical problem to be solved is to provide a highly corrosion-resistant and heat-resistant phenolic epoxy resin coating for oil pipes.

[0005] Technical solution: A corrosion-resistant phenolic epoxy resin coating for oil pipelines, comprising 100 parts by weight of phenolic epoxy resin, 0.8-1.2 parts by weight of dispersant, 0.8-1.5 parts by weight of defoamer, 46-60 parts by weight of filler, 18-30 parts by weight of curing agent, and 5-15 parts by weight of aminorosin-modified graphene.

[0006] The preparation method of anti-corrosion phenolic epoxy resin coating for oil pipelines is as follows: add phenolic epoxy resin, dispersant, defoamer and filler to a container, shear and disperse, and then add curing agent and amino rosin modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0007] Furthermore, the filler is any one or a combination of titanium dioxide, mica powder, talc powder, and quartz powder.

[0008] Furthermore, the curing agent is a polyetheramine curing agent or a polyamide curing agent.

[0009] Furthermore, the preparation method of aminorosin-modified graphene is as follows: N,N-dimethylformamide and graphene oxide are added to a reaction vessel and dispersed by ultrasonication. Then, aminorosin ester and N,N-dicyclohexylcarbodiimide are added, nitrogen gas is introduced, the temperature is raised to 40-55℃, and the reaction is stirred for 18-36 hours. N,N-dimethylformamide is removed by vacuum distillation, and the mixture is washed with water (aminorosin ester is not water-soluble and is not removed by washing). After drying, aminorosin-modified graphene is obtained. The aminorosin-modified graphene consists of aminorosin ester and graphene grafted with aminorosin ester.

[0010] Furthermore, the mass of aminorosin ester and N,N-dicyclohexylcarbodiimide are 400-1400% and 220-800% of the mass of graphene oxide, respectively.

[0011] Furthermore, the preparation method of aminorosin ester is as follows:

[0012] (1) Thionyl chloride is reacted with rosin acid to produce rosin acyl chloride; then, toluene, pyridine, and 1,3-di-(Boc-amino)-2-hydroxypropane are added to the reaction vessel in an ice bath, and rosin acyl chloride is added dropwise. The reaction is carried out at 40-50℃ for 4-6 h. After filtration, water is added to the filtrate, and the mixture is stirred and allowed to stand to separate into layers. The toluene organic phase is separated, and the solution is distilled under reduced pressure and dried to obtain Boc aminorosin ester. The reaction formula is as follows:

[0013] .

[0014] (2) Add an ethyl acetate solution of hydrochloric acid with a molar concentration of 4-5 mol / L and Boc aminorosin ester to the reaction vessel. React at 20-30℃ for 3-4 hours. Distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester. The reaction formula is as follows:

[0015] .

[0016] Furthermore, in (1), the masses of pyridine and 1,3-bis-(Boc-amino)-2-hydroxypropane are 90-108% and 26-32% of the mass of rosin acyl chloride, respectively.

[0017] The technical advantages of this invention are as follows: This invention utilizes 1,3-di-(Boc-amino)-2-hydroxypropane and rosin acyl chloride for esterification, followed by removal of the Boc protecting group to obtain aminorosin ester. Then, using N,N-dicyclohexylcarbodiimide as a condensing agent, one amino group of the aminorosin ester reacts with the carboxyl group on the surface of graphene oxide, thereby grafting a portion of the aminorosin ester onto the surface of graphene oxide to obtain aminorosin-modified graphene. Finally, using phenolic epoxy resin as the coating matrix, it is compounded with fillers such as talc, curing agents such as polyetheramine D230, defoamers, etc., to obtain an anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0018] The amino rosin ester of the present invention contains active amino groups, which can form a co-curing system with polyetheramine D230 and the like, and undergo a curing reaction with phenolic epoxy resin, thereby introducing heat-resistant rigid fused rings into the phenolic epoxy resin matrix, which is beneficial to improving the hardness of the paint film, while improving the hot water resistance and thermal weight loss temperature of the coating, exhibiting excellent heat resistance performance.

[0019] The graphene oxide of this invention is grafted with an amino rosin ester structure, which improves the interfacial compatibility between graphene and phenolic epoxy resin, improves the dispersibility of graphene in coatings, and is beneficial to improving the hardness of the coating film, as well as its resistance to salt spray, water and corrosion. Furthermore, the uniformly dispersed graphene also has a good effect on improving the heat resistance of the coating film. Detailed Implementation

[0020] Phenolic epoxy resin, model F51, Wuxi Jiunai Anticorrosion Materials Co., Ltd. Dispersant, model TF-800, Beijing Qifei Technology Development Co., Ltd. Defoamer, model KS-508, Guangzhou Siteyuan Chemical Co., Ltd. Graphene oxide, model Yuanye S25040, Shanghai Yuanye Biotechnology Co., Ltd.

[0021] The preparation method of rosin acyl chloride is as follows: 18 mL of thionyl chloride and 5 g of rosin acid are added to a reaction vessel, reacted at 60 °C for 3 h, followed by vacuum distillation and drying to obtain rosin acyl chloride. The structural formula is:

[0022] .

[0023] Example 1:

[0024] (1) In an ice bath, 60 mL of toluene, 1.4 g of pyridine, and 4.5 g of 1,3-di-(Boc-amino)-2-hydroxypropane were added to the reaction vessel, and 5 g of rosin acyl chloride was added dropwise. The reaction was carried out at 50 °C for 4 h. After filtration, water was added to the filtrate, and the mixture was stirred and allowed to stand to separate into layers. The toluene organic phase was separated, and the mixture was distilled under reduced pressure and dried to obtain Boc aminorosin ester.

[0025] (2) Add 50 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 5 mol / L and 8 g of Boc aminorosin ester to the reaction vessel, react at 25 °C for 4 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0026] (3) Add 1L of N,N-dimethylformamide and 1g of graphene oxide to the reaction vessel, disperse by ultrasonication, then add 4g of aminorosin ester and 2.2g of N,N-dicyclohexylcarbodiimide, introduce nitrogen gas, heat to 45℃, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, dry, and obtain aminorosin modified graphene.

[0027] (4) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, then add 30g curing agent polyetheramine D230 and 5g amino rosin modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0028] Example 2:

[0029] (1) In an ice bath, 80 mL of toluene, 1.6 g of pyridine, and 5.4 g of 1,3-di-(Boc-amino)-2-hydroxypropane were added to the reaction vessel, and 5 g of rosin acyl chloride was added dropwise. The reaction was carried out at 45 °C for 6 h. After filtration, water was added to the filtrate, and the mixture was stirred and allowed to stand to separate into layers. The toluene organic phase was separated, and the mixture was distilled under reduced pressure and dried to obtain Boc aminorosin ester.

[0030] (2) Add 60 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 4 mol / L and 8 g of Boc aminorosin ester to the reaction vessel, react at 20 °C for 4 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0031] (3) Add 1L of N,N-dimethylformamide and 1g of graphene oxide to the reaction vessel, disperse by ultrasonication, then add 7g of aminorosin ester and 3.7g of N,N-dicyclohexylcarbodiimide, introduce nitrogen gas, heat to 55℃, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, dry, and obtain aminorosin modified graphene.

[0032] (4) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 0.8g dispersant, 1.2g defoamer, and 46g filler titanium dioxide to the container, shear and disperse, then add 26g curing agent polyetheramine D230 and 8g amino rosin modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0033] Example 3:

[0034] (1) In an ice bath, 60 mL of toluene, 1.3 g of pyridine, and 4.8 g of 1,3-di-(Boc-amino)-2-hydroxypropane were added to the reaction vessel, and 5 g of rosin acyl chloride was added dropwise. The reaction was carried out at 40 °C for 6 h. After filtration, water was added to the filtrate, and the mixture was stirred and allowed to stand to separate into layers. The toluene organic phase was separated, and the mixture was distilled under reduced pressure and dried to obtain Boc aminorosin ester.

[0035] (2) Add 60 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 4 mol / L and 8 g of Boc aminorosin ester to the reaction vessel, react at 30 °C for 3 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0036] (3) Add 1.2L of N,N-dimethylformamide and 1g of graphene oxide to the reaction vessel, disperse by ultrasonication, then add 11g of aminorosin ester and 6.3g of N,N-dicyclohexylcarbodiimide, introduce nitrogen gas, heat to 40℃, stir and react for 36h, remove N,N-dimethylformamide by vacuum distillation, wash with water, dry, and obtain aminorosin modified graphene.

[0037] (4) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1.2g dispersant, 1.5g defoamer, and 55g filler quartz powder to the container, shear and disperse, then add 21g curing agent polyamide 651 and 12g amino rosin modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipes.

[0038] Example 4:

[0039] (1) Prepare amino rosin esters according to the method of Example 1.

[0040] (2) Add 1.2 L of N,N-dimethylformamide and 1 g of graphene oxide to the reaction vessel, disperse by ultrasonication, then add 14 g of aminorosin ester and 8 g of N,N-dicyclohexylcarbodiimide, introduce nitrogen gas, heat to 55 °C, stir and react for 24 h, remove N,N-dimethylformamide by vacuum distillation, wash with water, dry, and obtain aminorosin modified graphene.

[0041] (3) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1.2g dispersant, 1.2g defoamer, and 60g filler mica powder to the container, shear and disperse, then add 18g curing agent polyetheramine D230 and 15g amino rosin modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0042] Comparative Example 1:

[0043] (1) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, and then add 30g curing agent polyetheramine D230 to obtain anti-corrosion phenolic epoxy resin coating for oil pipes.

[0044] Comparative Example 2:

[0045] (1) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, then add 30g curing agent polyetheramine D230 and 1g graphene oxide to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0046] Comparative Example 3:

[0047] (1) Prepare amino rosin esters according to the method of Example 1.

[0048] (2) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, then add 30g curing agent polyetheramine D230 and 4g amino rosin ester to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0049] Comparative Example 4:

[0050] (1) Prepare amino rosin esters according to the method of Example 1.

[0051] (2) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, then add 30g curing agent polyetheramine D230, 1g graphene oxide, and 4g amino rosin ester to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0052] Comparative Example 5:

[0053] (1) Add 1L of N,N-dimethylformamide and 1g of graphene oxide to the reaction vessel, disperse by ultrasonication, then add 4g of ethylenediamine and 2.2g of N,N-dicyclohexylcarbodiimide, introduce nitrogen gas, heat to 45℃, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, dry, and obtain ethylenediamine modified graphene.

[0054] (2) Add 15mL xylene solvent, 10mL butanol solvent, 100g phenolic epoxy resin, 1g dispersant, 0.8g defoamer, and 53g talc to the container, shear and disperse, then add 30g curing agent polyetheramine D230 and 5g ethylenediamine modified graphene to obtain anti-corrosion phenolic epoxy resin coating for oil pipelines.

[0055] The curing conditions for phenolic epoxy resin coatings are: 25℃ for 24 hours, followed by 80℃ for 4 hours. The salt spray resistance of the coating film is tested according to GB / T1771-2007. Water resistance is tested according to GB / T 1733-1993, with a water temperature of 25-95℃. The hardness of the coating film is tested according to GB / T 6739-2022.

[0056] The paint film was subjected to thermogravimetric analysis in a nitrogen atmosphere, with the temperature increased from room temperature to 700℃ at a rate of 10℃ / min.

[0057] Table 1

[0058] Salt spray resistance (h) Pencil hardness Example 1 936 5H Example 2 1008 5H Example 3 1152 5H Example 4 1056 4H Comparative Example 1 720 2H Comparative Example 2 792 3H Comparative Example 3 744 3H Comparative Example 4 816 4H Comparative Example 5 912 4H

[0059] Table 2

[0060]

[0061] Table 3

[0062] Temperature at which 5% of the heat and gravity loss occurs (°C) Temperature at which 10% of the heat and gravity loss occurs (°C) Example 1 337.6 410.5 Example 2 341.1 413.5 Example 3 345.2 417.6 Example 4 346.0 416.9 Comparative Example 1 322.7 393.2 Comparative Example 2 323.8 394.9 Comparative Example 3 333.0 405.8 Comparative Example 4 334.7 407.3 Comparative Example 5 325.1 397.4

[0063] As shown in Table 1, Comparative Example 1, the phenolic epoxy coating, has a low salt spray resistance time, poor water resistance, and poor corrosion resistance; it also has low pencil hardness and poor mechanical properties; in addition, it has poor hot water resistance, low thermogravimetric loss temperature, and poor heat resistance.

[0064] The phenolic epoxy coatings in Examples 1-4 incorporated amino rosin-modified graphene. The amino rosin ester contains active amino groups, which can form a co-curing system with polyetheramine D230, etc., to cure the phenolic epoxy resin. This introduces heat-resistant, rigid, fused rings into the phenolic epoxy resin matrix, which is beneficial for improving the hardness of the coating film and significantly enhancing its heat resistance. After high-temperature hot water resistance tests, the coating film did not blister, crack, or peel, and exhibited a high thermal weight loss temperature, demonstrating excellent heat resistance. Simultaneously, the amino rosin ester structure grafted onto the surface of the graphene oxide provides better interfacial compatibility with the phenolic epoxy resin, improving the dispersibility of graphene in the coating. This contributes to increased film hardness, salt spray resistance, water resistance, and corrosion resistance. Furthermore, the uniformly dispersed graphene also contributes to improved heat resistance of the coating film.

[0065] Compared with Example 1, Comparative Example 2 only added graphene oxide and did not add amino rosin ester. The paint film had poor hot water resistance, low thermal weight loss temperature, and poor heat resistance. At the same time, the compatibility between graphene oxide and phenolic epoxy resin was poor, and its dispersion in the coating was not good, which was not conducive to improving the hardness, water resistance, salt spray resistance and heat resistance of the paint film.

[0066] Comparative Example 3 added amino rosin ester, which significantly improved the hot water resistance and thermogravimetric temperature of the coating film, and improved its heat resistance. However, it did not add uniformly dispersed graphene oxide, so the heat resistance, hardness, salt spray resistance and corrosion resistance of the coating film were lower than those of Example 1.

[0067] Comparative Example 4 included graphene oxide and amino rosin ester. Due to the poor compatibility between graphene oxide and phenolic epoxy resin, it did not disperse well in the coating, which was not conducive to improving the hardness, water resistance, salt spray resistance and heat resistance of the paint film.

[0068] The graphene oxide in Comparative Example 5, after being grafted with ethylenediamine, showed good compatibility with phenolic epoxy resin and excellent dispersibility in coatings. The hardness, salt spray resistance, and anti-corrosion performance of the coating film improved. However, the heat resistance of ethylenediamine was much lower than that of condensed-ring rosin, resulting in poor heat resistance of the coating film, as well as low hot water resistance and thermal weight loss temperature.

Claims

1. A corrosion-resistant phenolic epoxy resin coating for oil pipelines, characterized in that, The anti-corrosion phenolic epoxy resin coating for oil pipes comprises 100 parts by weight of phenolic epoxy resin, 0.8-1.2 parts by weight of dispersant, 0.8-1.5 parts by weight of defoamer, 46-60 parts by weight of filler, 18-30 parts by weight of curing agent, and 5-15 parts by weight of aminorosin-modified graphene. The preparation method of the aminorosin-modified graphene is as follows: N,N-dimethylformamide and graphene oxide are added to a reaction vessel and dispersed by ultrasonication. Then, aminorosin ester and N,N-dicyclohexylcarbodiimide are added, nitrogen gas is introduced, the reaction is stirred, and then the mixture is distilled under reduced pressure, washed with water, and dried to obtain aminorosin-modified graphene. The amino rosin ester has the following structural formula (Ⅰ): Equation (I); The aminorosin ester and N,N-dicyclohexylcarbodiimide are 400-1400% and 220-800% of the mass of graphene oxide, respectively.

2. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 1, characterized in that, The temperature during the stirring reaction is 40-55℃, and the reaction time is 18-36h.

3. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 1, characterized in that, The preparation method of the aminorosin ester is as follows: (1) Thionyl chloride is reacted with rosin acid to obtain rosin acyl chloride; then, toluene, pyridine, and 1,3-di-(Boc-amino)-2-hydroxypropane are added to the reaction vessel in an ice bath, and rosin acyl chloride is added dropwise. The reaction is carried out at 40-50℃ for 4-6 h. After filtration, water is added to the filtrate, and after stirring, the mixture is allowed to stand and separate into layers. The toluene organic phase is separated, and the mixture is distilled under reduced pressure and dried to obtain Boc aminorosin ester. (2) Add ethyl acetate solution of hydrochloric acid and Boc aminorosin ester to the reaction vessel, react at 20-30℃ for 3-4h, distill under reduced pressure, wash, and dry to obtain aminorosin ester.

4. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 3, characterized in that, In (1), the masses of pyridine and 1,3-bis-(Boc-amino)-2-hydroxypropane are 26-32% and 90-108% of the mass of rosin acyl chloride, respectively.

5. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 3, characterized in that, The molar concentration of the ethyl acetate hydrochloric acid solution in (2) is 4-5 mol / L.

6. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 1, characterized in that, The filler is any one or a combination of titanium dioxide, mica powder, talc powder, and quartz powder.

7. The anti-corrosion phenolic epoxy resin coating for oil pipelines according to claim 1, characterized in that, The curing agent is a polyetheramine curing agent or a polyamide curing agent.

8. A method for preparing an anti-corrosion phenolic epoxy resin coating for oil pipelines as described in any one of claims 1-7, characterized in that, The preparation method is as follows: phenolic epoxy resin, dispersant, defoamer, and filler are added to a container, sheared and dispersed, and then curing agent and amino rosin-modified graphene are added to obtain an anti-corrosion phenolic epoxy resin coating for oil pipelines.

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