Anticorrosive novolac epoxy resin coating for oil pipe and preparation method thereof

Abstract

The invention relates to the technical field of anticorrosive coatings, and discloses an anticorrosive novolac epoxy resin coating for oil pipes and a preparation method thereof, the anticorrosive novolac epoxy resin coating comprises 100 parts by weight of novolac epoxy resin, 18-30 parts by weight of a curing agent, and 5-15 parts by weight of amino rosin modified graphene; the surface of the graphene oxide is grafted with an amino abietate structure, so that the interfacial compatibility between the graphene and the novolac epoxy resin is improved, the dispersity of the graphene in the coating is improved, and the hardness, the salt mist resistance, the water resistance and the corrosion resistance of a paint film of the coating are improved; and the uniformly dispersed graphene also has a good effect of improving the heat resistance of the paint film. And the amino abietate contains active amino groups and can form a co-curing system with polyether amine D230 and the like to perform curing reaction on the novolac epoxy resin, so that the hardness, the hot water resistance and the thermal weight loss temperature of a paint film are favorably improved.

Description

Technical Field

[0001] The invention relates to the technical field of anti-corrosion coatings, in particular to an anti-corrosion phenolic epoxy resin coating for oil pipes and a preparation method thereof. Background Art

[0002] Anticorrosive coatings are widely used in the fields of petrochemicals, pipeline transportation, instruments and equipment, construction facilities, etc. They mainly include epoxy resin coatings, acrylic resin coatings, etc. Among them, phenolic epoxy resin is a linear phenolic polyglycidyl ether epoxy resin with good wear resistance, chemical resistance and curing properties. It is mainly used in mud tanks, sewage tanks, and tank inner walls of offshore oil production platforms. It is of great significance to develop high-performance heat-resistant, water-resistant, and anti-corrosive phenolic epoxy resins.

[0003] Abietic acid is a natural compound containing a tricyclic diterpene condensed ring structure. It is cheap, easy to obtain, green and environmentally friendly, and is widely used in materials such as coatings, plastics, and rubber. Graphene oxide has high mechanical strength, excellent high temperature resistance, and good electrical conductivity. Adding it to coatings can improve the heat resistance and salt spray resistance of coatings. Modifying the surface of graphene oxide and improving its dispersibility are research hotspots. The patent with publication number CN116082928A discloses that the anti-corrosion coating prepared by using rosin-modified o-cresol epoxy resin-based vinyl ester resin, quartz sand, epoxy reactive diluent, polyaniline-modified graphene, etc. as raw materials has good anti-corrosion performance and impact resistance. However, the patent does not improve the heat resistance and water resistance of the coating. Summary of the invention

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

[0005] Technical solution: An anticorrosive phenolic epoxy resin coating for oil pipes, 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 amino rosin modified graphene; The preparation method of the anticorrosive phenolic epoxy resin coating for oil pipes comprises the following steps: adding phenolic epoxy resin, dispersant, defoamer and filler into a container, shearing and dispersing, and then adding a curing agent and amino rosin modified graphene to obtain the anticorrosive phenolic epoxy resin coating for oil pipes.

[0006] Furthermore, the filler is any one or a combination of titanium dioxide, mica powder, talcum powder, and quartz powder.

[0007] Furthermore, the curing agent is a polyetheramine curing agent or a polyamide curing agent.

[0008] Furthermore, the preparation method of aminorosin modified graphene is as follows: add N,N-dimethylformamide and graphene oxide to a reaction container, disperse by ultrasound, then add aminorosin acid ester and N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 40-55°C, stir and react for 18-36h, remove N,N-dimethylformamide by vacuum distillation, wash with water (aminorosin acid ester is non-water-soluble and is not removed by washing), and dry to obtain aminorosin modified graphene. The aminorosin modified graphene is composed of aminorosin acid ester and graphene grafted with aminorosin acid ester.

[0009] Furthermore, the masses of aminorosin ester and N,N-dicyclohexylcarbodiimide are 400-1400% and 220-800% of the mass of graphene oxide, respectively.

[0010] Further, the preparation method of aminorosin acid ester is: (1) Carry out chlorination reaction of thionyl chloride and rosin acid to obtain rosin acid chloride; then, add toluene, pyridine, and 1,3-di-(Boc-amino)-2-hydroxypropane to the reaction vessel in an ice bath, dropwise add rosin acid chloride, react at 40-50°C for 4-6h, filter, add water to the filtrate, stir, stand and separate, obtain toluene organic phase, distill under reduced pressure, and dry to obtain Boc aminorosin acid ester. The reaction formula is as follows: .

[0011] (2) Add 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°C 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: .

[0012] Furthermore, the masses of pyridine and 1,3-di-(Boc-amino)-2-hydroxypropane in (1) are 90-108% and 26-32% of the mass of rosin acid chloride, respectively.

[0013] The technical effect of the present invention is as follows: the present invention utilizes 1,3-di-(Boc-amino)-2-hydroxypropane and rosin acid chloride for esterification reaction, and then removes the Boc protecting group to obtain aminorosin acid ester; then, N,N-dicyclohexylcarbodiimide is used as a condensation agent to react one amino group of aminorosin acid ester with the carboxyl group on the surface of graphene oxide, thereby grafting part of aminorosin acid ester onto the surface of graphene oxide to obtain aminorosin modified graphene. Finally, phenolic epoxy resin is used as the matrix of the coating, and is compounded with fillers such as talcum powder, curing agents such as polyetheramine D230, defoaming agents, etc. to obtain an anticorrosive phenolic epoxy resin coating for oil pipes.

[0014] The aminorosin acid ester of the present invention contains active amino groups, can form a co-curing system with polyetheramine D230 and the like, and undergo a curing reaction with the phenolic epoxy resin, thereby introducing a heat-resistant rigid condensed ring into the phenolic epoxy resin matrix, which is beneficial to improving the hardness of the paint film, while also improving the hot water resistance and thermal weight loss temperature of the coating, showing good heat resistance.

[0015] The surface of the graphene oxide of the present invention is grafted with an aminorosin acid ester structure, which improves the interface compatibility between the graphene and the phenolic epoxy resin, improves the dispersibility of the graphene in the coating, is beneficial to improving the hardness of the coating film, and has salt spray resistance, water resistance and corrosion resistance. The uniformly dispersed graphene also has a good effect of improving the heat resistance of the paint film. DETAILED DESCRIPTION

[0016] Phenolic epoxy resin, model F51, Wuxi Jiunai Anticorrosive Materials Co., Ltd. Dispersant, model TF-800, Beijing Qifei Technology Development Co., Ltd. Defoamer, model KS-508, Guangzhou Si Tuyuan Chemical Co., Ltd. Graphene oxide, model Yuanye S25040, Shanghai Yuanye Biotechnology Co., Ltd.

[0017] The preparation method of rosin acid chloride is as follows: add 18 mL of thionyl chloride and 5 g of rosin acid into a reaction container, react at 60°C for 3 hours, distill under reduced pressure, and dry to obtain rosin acid chloride. The structural formula is: .

[0018] Embodiment 1: (1) In an ice bath, add 60 mL of toluene, 1.4 g of pyridine, and 4.5 g of 1,3-di-(Boc-amino)-2-hydroxypropane to a reaction vessel, add 5 g of rosin acid chloride dropwise, and then react at 50°C for 4 h. After filtering, add water to the filtrate, stir and allow to stand to separate the layers, separate the toluene organic phase, distill under reduced pressure, and dry to obtain Boc aminorosin acid ester.

[0019] (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 a reaction container, react at 25°C for 4 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0020] (3) Add 1L N,N-dimethylformamide and 1g of graphene oxide to the reaction container, disperse it by ultrasonication, then add 4g of aminorosin ester and 2.2g of N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 45°C, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, and dry to obtain aminorosin modified graphene.

[0021] (4) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoaming agent, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230 and 5 g of amino rosin modified graphene to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0022] Embodiment 2: (1) In an ice bath, add 80 mL of toluene, 1.6 g of pyridine, and 5.4 g of 1,3-di-(Boc-amino)-2-hydroxypropane to a reaction vessel, add 5 g of rosin acid chloride dropwise, and then react at 45°C for 6 h. After filtering, add water to the filtrate, stir and allow to stand to separate the layers, separate the toluene organic phase, distill under reduced pressure, and dry to obtain Boc aminorosin ester.

[0023] (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 a reaction container, react at 20°C for 4 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0024] (3) Add 1L N,N-dimethylformamide and 1g of graphene oxide to the reaction container, disperse it by ultrasonication, then add 7g of aminorosin ester and 3.7g of N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 55°C, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, and dry to obtain aminorosin modified graphene.

[0025] (4) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 0.8 g of dispersant, 1.2 g of defoamer, and 46 g of filler titanium dioxide into a container, shear and disperse, and then add 26 g of curing agent polyetheramine D230 and 8 g of amino rosin modified graphene to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0026] Embodiment 3: (1) In an ice bath, add 60 mL of toluene, 1.3 g of pyridine, and 4.8 g of 1,3-di-(Boc-amino)-2-hydroxypropane to a reaction vessel, add 5 g of rosin acid chloride dropwise, and then react at 40°C for 6 h. After filtering, add water to the filtrate, stir and allow to stand to separate the layers, separate the toluene organic phase, distill under reduced pressure, and dry to obtain Boc aminorosin acid ester.

[0027] (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 a reaction container, react at 30°C for 3 h, distill under reduced pressure, wash with saturated sodium bicarbonate solution, and dry to obtain aminorosin ester.

[0028] (3) Add 1.2L N,N-dimethylformamide and 1g of graphene oxide to the reaction container, disperse it by ultrasonication, then add 11g of aminorosin ester and 6.3g of N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 40°C, stir and react for 36h, remove N,N-dimethylformamide by vacuum distillation, wash with water, and dry to obtain aminorosin modified graphene.

[0029] (4) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1.2 g of dispersant, 1.5 g of defoaming agent, and 55 g of filler quartz powder into a container, shear and disperse, and then add 21 g of curing agent polyamide 651 and 12 g of amino rosin modified graphene to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0030] Embodiment 4: (1) Prepare aminorosin ester according to the method of Example 1.

[0031] (2) Add 1.2L N,N-dimethylformamide and 1g of graphene oxide to a reaction container, disperse by ultrasonication, then add 14g of aminorosin ester and 8g of N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 55°C, stir to react for 24h, remove N,N-dimethylformamide by vacuum distillation, wash with water, and dry to obtain aminorosin modified graphene.

[0032] (3) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1.2 g of dispersant, 1.2 g of defoamer, and 60 g of filler mica powder into a container, shear and disperse, and then add 18 g of curing agent polyetheramine D230 and 15 g of amino rosin modified graphene to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0033] Comparative Example 1: (1) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoamer, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230 to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0034] Comparative Example 2: (1) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoaming agent, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230 and 1 g of graphene oxide to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0035] Comparative Example 3: (1) Prepare aminorosin ester according to the method of Example 1.

[0036] (2) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoaming agent, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230 and 4 g of aminorosin acid ester to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0037] Comparative Example 4: (1) Prepare aminorosin ester according to the method of Example 1.

[0038] (2) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoaming agent, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230, 1 g of graphene oxide, and 4 g of aminorosin acid ester to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0039] Comparative Example 5: (1) Add 1L N,N-dimethylformamide and 1g of graphene oxide to a reaction container, disperse by ultrasonication, then add 4g of ethylenediamine and 2.2g of N,N-dicyclohexylcarbodiimide, introduce nitrogen, heat to 45°C, stir and react for 18h, remove N,N-dimethylformamide by vacuum distillation, wash with water, and dry to obtain ethylenediamine-modified graphene.

[0040] (2) Add 15 mL of xylene solvent, 10 mL of butanol solvent, 100 g of phenolic epoxy resin, 1 g of dispersant, 0.8 g of defoaming agent, and 53 g of talcum powder into a container, shear and disperse, and then add 30 g of curing agent polyetheramine D230 and 5 g of ethylenediamine-modified graphene to obtain an anti-corrosion phenolic epoxy resin coating for oil pipes.

[0041] The curing conditions of phenolic epoxy resin coating are 25℃ for 24h, and then 80℃ for 4h. The salt spray resistance of the paint film is tested according to GB / T1771-2007. The water resistance is tested according to GB / T 1733-1993, and the water temperature is 25-95℃. The hardness of the paint film is tested according to GB / T 6739-2022.

[0042] The paint film was placed in a thermogravimetric analyzer in a nitrogen atmosphere at a heating rate of 10°C / min from room temperature to 700°C for thermogravimetric performance testing.

[0043] Table 1 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 Table 2 Table 3 Temperature at which the thermogravimetric loss is 5% (°C) Temperature at which the thermogravimetric loss is 10% (°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 As shown in Table 1, the phenolic epoxy coating in Comparative Example 1 has a low salt spray resistance time, poor water resistance, and poor corrosion resistance; and a low pencil hardness and poor mechanical properties; at the same time, it has poor hot water resistance, a low thermogravimetric loss temperature, and poor heat resistance.

[0045] The phenolic epoxy coating of embodiment 1-4 has added aminorosin modified graphene, wherein aminorosin acid ester contains active amino group, can form co-curing system with polyetheramine D230 etc., carries out curing reaction to phenolic epoxy resin, and heat-resistant rigid condensed ring is introduced into phenolic epoxy resin matrix, is conducive to improving the hardness of paint film, and significantly improves the heat resistance of coating simultaneously, through high temperature hot water resistant test, paint film does not bubble, does not crack, does not fall off, and the thermal weight loss temperature of paint film is high, and heat resistance is very good. At the same time, the surface of graphene oxide is grafted with aminorosin acid ester structure, has better interface compatibility with phenolic epoxy resin, improves the dispersibility of graphene in coating, is conducive to improving the hardness of coating paint film, and salt spray resistance, water resistance and anticorrosion performance, and the evenly dispersed graphene also has a certain improvement effect on the heat resistance of paint film.

[0046] Compared with Example 1, in Comparative Example 2, only graphene oxide is added without aminorosin ester. The paint film has poor hot water resistance, low thermal weight loss temperature, and poor heat resistance. At the same time, graphene oxide has poor compatibility with phenolic epoxy resin and poor dispersibility in the coating, which is not conducive to improving the hardness, water resistance, salt spray resistance and heat resistance of the paint film.

[0047] In Comparative Example 3, aminorosin ester was added, and the hot water resistance and thermal weight loss temperature of the paint film were significantly improved, and the heat resistance became better, but no uniformly dispersed graphene oxide was added, and the heat resistance, hardness, salt spray resistance and corrosion resistance of the paint film were lower than those in Example 1.

[0048] Comparative Example 4 added graphene oxide and aminorosin ester. Since graphene oxide has poor compatibility with phenolic epoxy resin, it has poor dispersibility in the coating, which is not conducive to improving the hardness, water resistance, salt spray resistance and heat resistance of the paint film.

[0049] After the graphene oxide in Comparative Example 5 is grafted with ethylenediamine, it has good compatibility with phenolic epoxy resin, excellent dispersibility in the coating, and the hardness, salt spray resistance and corrosion resistance of the paint film are improved. However, the heat resistance of ethylenediamine is much lower than that of polycyclic rosin, resulting in poor heat resistance of the paint film, low hot water resistance and thermal weight loss temperature.

Claims

1. An anticorrosive phenolic epoxy resin coating for oil pipes, characterized in that: The anticorrosive phenolic epoxy resin coating for oil pipe 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 amino rosin modified graphene; The preparation method of the aminorosin modified graphene is as follows: N,N-dimethylformamide and graphene oxide are added into a reaction container, dispersed by ultrasonication, and then aminorosin acid ester and N,N-dicyclohexylcarbodiimide are added, nitrogen is introduced, and after stirring for reaction, the mixture is distilled under reduced pressure, washed with water, and dried to obtain the aminorosin modified graphene; The aminorosin acid ester has the following structural formula (I): Formula (I).

2. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 1, characterized in that: The masses of the aminorosin ester and N,N-dicyclohexylcarbodiimide are 400-1400% and 220-800% of the mass of graphene oxide respectively.

3. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 1, characterized in that: The temperature during the stirring reaction is 40-55° C., and the reaction time is 18-36 hours.

4. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 2, characterized in that: The preparation method of the aminorosin ester is: (1) Carry out chlorination reaction of thionyl chloride and rosin acid to obtain rosin acid chloride; then, add toluene, pyridine, and 1,3-di-(Boc-amino)-2-hydroxypropane to the reaction vessel in an ice bath, dropwise add rosin acid chloride, and then react at 40-50° C. for 4-6 hours. After filtering, add water to the filtrate, stir and stand to separate, separate toluene organic phase, distill under reduced pressure, and dry to obtain Boc aminorosin acid ester; (2) Add ethyl acetate solution of hydrochloric acid and Boc aminorosin ester to the reaction vessel, react at 20-30°C for 3-4 hours, distill under reduced pressure, wash, and dry to obtain aminorosin ester.

5. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 4, characterized in that: The masses of pyridine and 1,3-di-(Boc-amino)-2-hydroxypropane in (1) are 90-108% and 26-32% of the mass of rosin acid chloride, respectively.

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

7. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 1, characterized in that: The filler is any one or a combination of titanium dioxide, mica powder, talcum powder and quartz powder.

8. The anticorrosive phenolic epoxy resin coating for oil pipe according to claim 1, characterized in that: The curing agent is a polyetheramine curing agent or a polyamide curing agent.

9. A method for preparing the anticorrosive phenolic epoxy resin coating for oil pipe according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: adding phenolic epoxy resin, dispersant, defoamer and filler into a container, shearing and dispersing, and then adding a curing agent and amino rosin modified graphene to obtain an anticorrosive phenolic epoxy resin coating for oil pipes.

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