A high elongation petroleum pipeline repair coating epoxy resin composition

Abstract

The application relates to a high-elongation petroleum pipeline repair coating epoxy resin composition, relates to the technical field of high polymer materials, and is composed of A component and B component in a weight ratio of 3:1. The A component comprises the following raw materials in parts by weight: 60-80 parts of polyurethane modified epoxy resin, 5-15 parts of polyether modified epoxy resin and 15-25 parts of polyurethane modified active diluent. The B component comprises the following raw materials in percentage by mass: 10-90% of polyether amine and 10-90% of polyamide. The polyurethane modified active diluent is prepared by modifying the active diluent with oxazolidinone. The active diluent is modified with polyurethane, and the polyurethane modified active diluent is used to modify the polyether modified epoxy resin, so that the elongation at break of the cured product can be improved, the tensile strength is not significantly reduced, the adhesive strength can be improved, and the requirements of pipeline repair coating on strength and elongation are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a high-elongation petroleum pipeline repair coating epoxy resin composition. BACKGROUND

[0002] With the rapid development of global economy, the demand for energy is rising, and the development of oil and gas pipeline transportation is rapid. Due to the influence of environmental and use conditions and other factors, corrosion problems will inevitably occur in the pipeline during use. Coating corrosion is an effective means to protect the pipeline. When the pipeline is used for a certain period of time and loses effective protection due to corrosion damage, the coating needs to be repaired.

[0003] The coating repair material currently used is mainly epoxy resin material. Epoxy resin is a thermosetting resin, which has excellent physical and mechanical properties, electrical insulation properties, chemical resistance and adhesion. Therefore, it is often used as a coating for pipeline repair.

[0004] However, epoxy resin materials generally have high brittleness and are prone to cracking. In order to obtain a high-elasticity epoxy resin system, the existing process adds long-chain active diluents and elastomers (such as polyurethane elastomers or rubber modifiers), and uses flexible polyether amine as a curing agent. Although a high-elongation epoxy resin system can be obtained, the strength of the prepared epoxy resin material is low, and in addition, there are disadvantages such as slow curing speed and high viscosity, which cannot meet the requirements of high strength and high elongation of pipeline repair coating. SUMMARY

[0005] In order to solve the problem that the epoxy resin cannot meet the requirements of high strength, high toughness and high elongation of pipeline repair coating, the present application provides a high-elongation petroleum pipeline repair coating epoxy resin composition. Through special active diluent modification technology, the shortcomings of insufficient elongation and strength of the existing elastic epoxy resin composition are overcome.

[0006] In a first aspect, the present application provides a high-elongation pipeline repair coating epoxy resin composition, which is composed of A component and B component mixed according to a weight ratio of 3:1.

[0007] The A component includes the following raw materials in parts by weight:

[0008] 60-80 parts of polyurethane modified epoxy resin, 5-15 parts of polyether modified epoxy resin, and 15-25 parts of polyurethane modified active diluent;

[0009] The B component includes the following raw materials in mass percentage: 10-90% of polyether amine and 10-90% of polyamide.

[0010] The polyurethane modified active diluent is prepared by oxazolidone modification of the active diluent, and the polyurethane modified active diluent after oxazolidone modification is a liquid.

[0011] Further, the polyurethane modified active diluent is prepared by the following method:

[0012] The catalyst and hydrogenated xylylene diisocyanate are sequentially added to the active diluent, and the oxazolidone modification reaction is carried out under constant temperature stirring in a protective atmosphere to obtain a reaction liquid.

[0013] During the constant temperature stirring, the isocyanate group content of the reaction liquid is monitored, and when the isocyanate group content of the reaction liquid is ≤0.1%, the heating is stopped, and the polyurethane modified active diluent is obtained after cooling.

[0014] Further, the molar ratio of the hydrogenated xylylene diisocyanate to the active diluent is 1: (3-6).

[0015] Preferably, the molar ratio of the hydrogenated xylylene diisocyanate to the active diluent is 1:5.

[0016] Further, the temperature of the constant temperature stirring is 130-180℃, and the time is 2-5h.

[0017] Further, the active diluent is selected from any one of neopentyl glycol diglycidyl ether, 1, 4 butanediol diglycidyl ether and hexanediol diglycidyl ether.

[0018] Further, the catalyst is selected from any one of 1-methylimidazole, 2-methylimidazole and 2-ethyl 4-methylimidazole, and the catalyst accounts for 0.01%-0.5% of the total mass of the active diluent and the hydrogenated xylylene diisocyanate.

[0019] In the second aspect, the application provides a preparation method of the A component, and the preparation method of the A component comprises:

[0020] The polyurethane modified epoxy resin is heated and stirred, and then the polyether modified epoxy resin and the polyurethane modified active diluent are sequentially added to the polyurethane modified epoxy resin, and after stirring and filtering, the A component is obtained.

[0021] Further, the temperature of the heating and stirring is 60-100℃, and the stirring time in the stirring and filtering is 20-40min.

[0022] In summary, the application has at least one of the following beneficial technical effects:

[0023] 1. The application overcomes the shortcomings of traditional active diluents, which will significantly reduce the performance of the cured product if the addition amount exceeds a certain range. The modified active diluent is used to further modify the polyether-modified epoxy resin, which greatly improves the elongation at break of the cured product without significantly reducing the tensile strength, and can improve the bonding strength, thereby meeting the requirements of pipeline repair coating on strength and elongation, toughness;

[0024] 2. The epoxy resin composition prepared in the application has low viscosity, viscosity ≤5000 cps@25℃, and when prepared into pipeline repair coating, it does not need to add additional diluent for dilution, which reduces the preparation cost and can effectively avoid the performance reduction of strength, elongation and other properties caused by the addition of diluent;

[0025] 3. The epoxy resin composition prepared in the application has excellent bonding performance when used in oil pipeline repair coating, and effectively overcomes the drawbacks of conventional repair coating which needs to be repaired repeatedly. It has excellent interfacial spreading property for the repaired pipeline, and the oxazolidone ring and the active hydrogen at the bonded site can form hydrogen bond interaction, so it has high bonding and sealing performance and high strength. Therefore, it can greatly prolong the service life of the oil pipeline and effectively reduce the construction frequency;

[0026] 4. The epoxy resin composition prepared in the application has low viscosity, and the introduced oxazolidone modified diluent resin has toughening effect, while the viscosity is low, which overcomes the disadvantage of increasing viscosity caused by the addition of conventional toughening agents such as rubber, core-shell powder and the like;

[0027] 5. It is also found that the oxazolidone modified diluent has good reactivity, so that the composition of the application has a faster reaction speed, which overcomes the technical problem of reducing the reactivity caused by the introduction of polyether resin and the like, and improves the construction efficiency;

[0028] 6. In addition, due to the problems such as thin glue layer, easy to appear crack gap, change of coating surface polarity of the inner wall of the pipeline at the corroded part of the pipeline, the repair glue also needs to have excellent bonding and sealing property for the thinned glue layer and the inner wall of the pipeline at the crack gap. Benefiting from the characteristics of the epoxy resin of the application, the repair frequency can be effectively reduced and the construction efficiency can be improved. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in combination with examples. It should be particularly noted that: in the following examples, if the specific conditions are not specified, the conventional conditions or the conditions recommended by the manufacturer are used; in the following examples, the raw materials used can be obtained from ordinary market sources unless otherwise specified.

[0030] The application provides a high-elongation pipeline repair coating epoxy resin composition. With the rapid development of the global economy, the demand for energy is rising, and the development of oil and gas pipeline transportation is rapid. Due to the influence of environmental and use conditions and other factors, corrosion will inevitably occur during the use of the pipeline.

[0031] In order to protect the pipeline, some corrosion protection measures will be taken, for example:

[0032] (1) Anti-corrosion coating, that is, a layer of anti-corrosion coating such as epoxy coating, polyurea coating and polyester coating is coated on the surface of the pipeline. These coatings can isolate the pipeline from the external environment and prevent corrosive media from corroding the pipeline;

[0033] (2) Hot-dip galvanizing, that is, the pipeline is immersed in molten zinc to form a protective layer of zinc. Zinc has good corrosion resistance and can prevent the pipeline from being oxidized and corroded;

[0034] (3) Polyethylene wrapping, that is, a layer of polyethylene material is wrapped on the surface of the pipeline to form a protective layer. Polyethylene has good corrosion resistance and can prevent the pipeline from being corroded by chemical media;

[0035] (4) Anodic protection, that is, an anodic protection device is installed on the pipeline to make the surface of the pipeline become an anode to prevent the flow of corrosion current and protect the pipeline from corrosion;

[0036] (5) Corrosion inhibitor, that is, a certain amount of corrosion inhibitor is added to the pipeline to inhibit the corrosion of corrosive media on the pipeline. Considering the economy and convenience, the first anti-corrosion coating is the most widely used corrosion protection measure.

[0037] The most important method in the anticorrosion coating method is anticorrosion coating considering economy, convenience and practicability. When the pipeline is used for a certain period of time and loses effective protection due to corrosion damage, coating repair can be carried out. Epoxy resin has excellent physical and mechanical properties, electrical insulation properties, chemical resistance and adhesion, and is the most popular anticorrosion coating. However, epoxy resin generally has problems such as high brittleness and easy cracking, which will affect the anticorrosion effect of the coating. The reason is that the pipeline will be affected by temperature changes during use, resulting in thermal expansion and contraction. The high brittleness of the anticorrosion coating cannot adapt to the deformation of the pipeline, resulting in cracking or falling off. The pipeline system will vibrate and shake due to external force, which will affect the coating and cause cracking and damage to the coating. The pipeline substrate also deforms due to external force or other reasons, such as bending, stretching, etc. Coatings with low elasticity and low elongation are not convenient to follow the deformation of the substrate, and it is difficult to maintain the integrity and adhesion of the coating. The pipeline will also be subjected to external impact or collision during use, such as mechanical device operation, object impact, etc. Coatings with low elasticity and low elongation are difficult to absorb and disperse impact force, causing damage to the coating. Finally, the pipeline is usually in a complex use environment, such as underground, underwater, high temperature, low temperature, etc. Coatings with low elasticity and low elongation have poor environmental adaptability and are not convenient to maintain stability and protection effect.

[0038] Therefore, in order to obtain a high-elasticity epoxy resin system, the prior art usually adopts the method of adding long-chain active diluents and elastomers (such as polyurethane elastomers or rubber modifiers), for example: using E51 epoxy resin and long-chain active diluents, and polyether amine, amine curing agent and long-chain phenol, formaldehyde to prepare a Mannich modified curing agent, polyurethane active toughening agent, DMP-30 accelerator. The tensile strength of the epoxy resin material prepared by the above method can only reach about 6 MPa; or using E51 or F51 epoxy resin, modifying by active diluent benzyl glycidyl ether and AGE, adding polyether amine D400 and high-activity modified amine to mix to form an epoxy resin material. The elongation at break of the epoxy resin material prepared by the above method can reach 80-120%, but the tensile strength is also low and the curing speed is slow; using bisphenol A epoxy and bisphenol F epoxy, adding active diluents and rubber toughening agents, the elongation at break of the obtained resin composition is also relatively poor. Therefore, the epoxy resin system prepared by the above method cannot meet the requirements of high strength and high elongation of pipeline repair coating.

[0039] In addition to being applied to pipeline anticorrosion, coatings are also applied to replace the inner tube technology of petroleum pipelines. The inner tube lining is high-density polyethylene. The main problems of the inner tube technology at present are: 1. It is difficult to insert the tube at the bend, and it does not fit well with the metal pipe; 2. The pipe joint is not easy to handle; 3. The pipeline is prone to aging under the action of medium and high temperature, and has a short service life.

[0040] Based on the above problems, the present application provides a high-elongation petroleum pipeline repair coating epoxy resin composition, which overcomes the shortcomings of traditional active diluents by modifying the active diluent with polyurethane, and further modifies the polyether-modified epoxy resin with the modified active diluent, thereby greatly improving the elongation at break of the cured product without significantly reducing the tensile strength and improving the adhesive strength, thereby meeting the requirements of pipeline repair coating on strength and elongation. Furthermore, the epoxy resin material prepared by the present application can be used as a petroleum pipeline repair coating, which can be applied on site and can be repeatedly coated, can adapt to complex pipeline construction, and does not have joints. The coating has good temperature resistance and medium resistance, and has a service life much higher than that of the inner tube technology.

[0041] The epoxy resin composition of the present application is composed of A part and B part mixed together, and the weight ratio of A component to B component is 3:1. Among them, the A component includes raw materials in the following weight parts: 60-80 parts of polyurethane-modified epoxy resin, 5-15 parts of polyether-modified epoxy resin, and 15-25 parts of polyurethane-modified active diluent; preferably, 70 parts of polyurethane-modified epoxy resin, 10 parts of polyether-modified epoxy resin, and 20 parts of polyurethane-modified active diluent.

[0042] The B component includes raw materials in the following mass percentages: 10-90% of polyether amine and 10-90% of polyamide.

[0043] The preparation method of the above-mentioned A component is as follows: the polyurethane-modified epoxy resin is heated and stirred, then the polyether-modified epoxy resin and the polyurethane-modified active diluent are sequentially added into the polyurethane-modified epoxy resin, and after stirring and filtering, the A component is obtained.

[0044] Among them, the temperature of heating and stirring is 60-100℃, and the stirring time in stirring and filtering is 20-40min. Preferably, the temperature of heating and stirring is 80℃, and the stirring time in stirring and filtering is 30min, which helps to uniformly mix the components and improve the homogeneity of the A component.

[0045] The composition A has good flexibility, and after modification, it can reduce the viscosity of the coating for easy defoaming, and can further improve the toughness without significantly reducing the strength of the matrix, thereby better balancing the strength and toughness.

[0046] The polyurethane-modified active diluent in the above-mentioned A component is prepared by oxazolidinone modification of the following raw materials in weight parts:

[0047] 4-8 parts of active diluent, 0.6-1.3 parts of hydrogenated xylene diisocyanate (hereinafter referred to as H6XDI), and 0.01-0.05 parts of catalyst; preferably, 6 parts of active diluent, 0.75 parts of H6XDI, and 0.017 parts of catalyst.

[0048] The active diluent can be any one of neopentyl glycol diglycidyl ether, 1,4 butanediol diglycidyl ether, hexanediol diglycidyl ether and C12-14 alkyl glycidyl ether; the catalyst can be any one of 1-methyl imidazole, 2-methyl imidazole, 2-ethyl 4-methyl imidazole, 2-phenyl imidazole, triphenyl phosphine catalyst, tertiary amine, Lewis acid, Lewis base and boron trifluoride complex salt. Preferably, the active diluent is neopentyl glycol diglycidyl ether, the catalyst is 1-methyl imidazole, the 1-methyl imidazole accounts for 0.01%-0.5% of the total mass of neopentyl glycol diglycidyl ether and H6XDI, and preferably, the 1-methyl imidazole accounts for 0.03% of the total mass of neopentyl glycol diglycidyl ether and H6XDI.

[0049] The preparation method of the polyurethane modified active diluent includes:

[0050] 0.75 parts of H6XDI and 0.017 parts of 1-methyl imidazole are sequentially added into 5 parts of neopentyl glycol diglycidyl ether, heated to 130-180°C under a protective atmosphere and kept for 2-5h, stirred and subjected to oxazolidone modification reaction to obtain a reaction solution. The protective atmosphere is any one of nitrogen, helium, neon, argon, krypton, xenon and radon, and is preferably nitrogen. The heating temperature is preferably 150°C, and the keeping time is preferably 3h. During the heating process, first, low temperature 40-60°C for 1-3h to allow the first part of NCO to react; then high temperature 60-100°C for 1-3h to allow the remaining NCO to participate in the reaction. The purpose of the low-temperature first and then high-temperature reaction is to inhibit isocyanate self-polymerization and inhibit the generation of by-products such as urea-based carbamic acid. Finally, 150°C for 3h to obtain an oxazolidone structure; during the constant-temperature stirring process, the isocyanate group content of the reaction solution is monitored, and when the isocyanate group content of the reaction solution reaches <0.1%, the heating is stopped, and after cooling, the polyurethane modified active diluent is obtained.

[0051] The detection method of the isocyanate group includes: reacting the isocyanate group with excess di-n-butylamine to generate urea, and then titrating the excess di-n-butylamine with hydrochloric acid to quantitatively calculate the isocyanate group content.

[0052] The oxazolidone structure is generated by the reaction of the epoxy group on the active diluent with H6XDI.

[0053] Oxazolidone is a five-membered heterocyclic structure, which can improve the strength, heat resistance and adhesion to pigments and fillers of the resin, and a reasonable modification route can also simultaneously improve the toughness of the resin.

[0054] The amount of H6XDI needs to be controlled for partial oxazolidone modification of the active diluent. Too little H6XDI will not have a modification effect. Too much H6XDI will make the modified active diluent too viscous, and thus will not have a viscosity-reducing effect. Therefore, the molar ratio of H6XDI to neopentyl glycol diglycidyl ether is preferably about 1:6.

[0055] When the diluent and the epoxy resin are oxazolidone-modified, the rigid chain and the flexible chain work together to simultaneously increase the strength and toughness of the resin. In addition, oxazolidone modification, with increasing active diluent content, has little effect on the decrease of triglyceride (Tg) and can effectively improve the toughness of the resin, while having little effect on the heat resistance. Therefore, by modifying the active diluent with polyurethane, the shortcomings of traditional active diluents, which will significantly reduce the performance of the cured product when the addition amount exceeds a certain range, are overcome. The use of the modified active diluent for further modification of the polyether-modified epoxy resin can greatly improve the elongation at break of the cured product, without significantly reducing the tensile strength, and can improve the bonding strength, thereby meeting the requirements of pipe repair coatings for strength and elongation.

[0056] The above-mentioned B component includes raw materials in the following mass percentages: 10-90% polyether amine and 10-90% polyamide, wherein the polyether amine provides toughness and the polyamide provides adhesion, specifically: 90% polyether amine and 10% polyamide, or 10% polyether amine and 90% polyamide. When the polyamide / polyether amine = 90:10, the composition has good adhesion, but the elongation at break is relatively low; when the polyamide / polyether amine = 10:90, the obtained composition has good toughness. Example

[0057] Example 1

[0058] The epoxy resin composition is composed of A component and B component in a weight ratio of 3:1, wherein the A component includes raw materials in the following weight parts:

[0059] 51.70 Kg of polyurethane-modified epoxy resin, 10.35 Kg of polyether-modified epoxy resin, and 15.51 Kg of polyurethane-modified active diluent; the B component includes 2.24 Kg of polyether amine and 20.20 Kg of polyamide.

[0060] The polyurethane active diluent includes the following raw materials in weight parts: 100 g of neopentyl glycol diglycidyl ether, 15 g of H6XDI, and 0.34 g of 1-methylimidazole.

[0061] The preparation method of the polyurethane active diluent includes:

[0062] 1. Put 100 g of neopentyl glycol diglycidyl ether into a three-necked flask, add 15 g of H6XDI while stirring, then add 0.34 g of 1-methylimidazole, heat to 50°C under nitrogen protection and keep for 2 h, then heat to 90°C and keep for 2 h, and finally heat to 150°C and keep for 3 h, stir and carry out oxazolidone modification reaction to obtain a reaction solution;

[0063] 2. Monitor the isocyanate group content of the reaction solution during constant temperature stirring, stop heating when the isocyanate group content of the reaction solution reaches <0.1%, and obtain a polyurethane modified active diluent after cooling.

[0064] The preparation method of the A component comprises:

[0065] 1. Put the polyurethane modified epoxy resin into a container, heat to 80°C, and then add the polyether modified epoxy resin and the polyurethane modified active diluent after stirring;

[0066] 2. After stirring for 30 min, filter and package to obtain the A component.

[0067] Example 2-3

[0068] Example 2-3 differs from Example 1 in that the amount of H6XDI used is different, as shown in Table 1 below.

[0069] Table 1. Amount of H6XDI (g)

[0070]

[0071] The effect of adding different amounts of H6XDI on the viscosity of the cured product after modification treatment of the polyurethane modified active diluent was investigated, and the detection method was in accordance with GB10247. The detection results are shown in Table 2 below.

[0072] Table 2. Viscosity of active diluent

[0073]

[0074] Conclusion: According to Table 2, it can be obtained that when the amount of H6XDI added is small, the viscosity of the modified active diluent obtained is small, but the modification effect is not significant; when the amount of H6XDI added exceeds 20.5 g, the viscosity increases greatly, the dilution effect is not good, and the purpose of viscosity reduction and foam elimination cannot be achieved, therefore, the amount of H6XDI added is best controlled within the range given in Example 1.

[0075] Example 4-7

[0076] Example 4-7 differs from Example 1 in that different types of active diluents and catalysts are used, as shown in Table 3 below.

[0077] Table 3. Types of active diluent and catalyst

[0078]

[0079] The influence of different active diluents and catalysts on the reaction rate and viscosity of the prepared epoxy resin composition was investigated. The detection method was in accordance with GB / T10247, the reaction rate was sorted by testing the gel time of the epoxy resin composition at 50°C, and the test results were shown in Table 4 below.

[0080] Table 4. Reaction rate of epoxy resin composition

[0081]

[0082] Conclusion: The reaction rate of neopentyl glycol diglycidyl ether was the fastest, and the viscosity of the composition was smaller, which might be due to the shortest molecular chain of neopentyl glycol and the closest distance of epoxy groups. Therefore, the active diluent was preferably neopentyl glycol diglycidyl ether, and the catalyst was preferably 1-methylimidazole.

[0083] Examples 8-9

[0084] Examples 8-9 were different from Example 1 in that the temperature reached during the preparation of the polyurethane active diluent and the stirring time were different, as shown in Table 5 below.

[0085] Table 5. Temperature and stirring time of heating

[0086]

[0087] The influence of the polyurethane active diluent prepared at different temperatures and times on the performance of the cured product was investigated, and the test results were shown in Table 6 below.

[0088] Table 6. Performance of epoxy resin composition

[0089]

[0090] Conclusion: According to Table 6, it could be obtained that the epoxy resin composition prepared by heating to 150°C and holding for 3h had the best balance of strength and elongation at break. If the temperature and stirring time were reduced, the tensile strength and elongation at break would both decrease. If the temperature was increased and the time was prolonged, the elongation at break would decrease by about 50% compared to Example 1. If only the temperature was changed without changing the stirring time, similar problems would also occur. Therefore, when preparing the polyurethane active diluent, heating to 150°C and holding for 3h was the best.

[0091] Comparative Example 5

[0092] The epoxy resin composition was composed of A component and B component mixed in a weight ratio of 3:1, wherein the A component included raw materials in the following weight parts:

[0093] 51.70 Kg polyurethane-modified epoxy resin, 10.35 Kg polyether-modified epoxy resin and 15.51 Kg neopentyl glycol diglycidyl ether;

[0094] The B component comprises raw materials in parts by weight as follows: 2.24 Kg polyether amine and 20.20 Kg polyamide.

[0095] Comparative Example 6

[0096] Comparative Example 6 differs from Example 1 only in that hexamethylene-1,6-diisocyanate is used to modify neopentyl glycol diglycidyl ether.

[0097] I. The influence of active diluent modification on the properties of the cured product was detected, and the epoxy resin compositions prepared in Example 1, Comparative Example 5 and Comparative Example 6 were selected. The detection method was in accordance with GB / T 2567-2021, and the curing conditions were 70°C / 16h. The detection results are shown in Table 7 below.

[0098] Table 7. Influence of active diluent modification on the properties of the cured product

[0099]

[0100] As can be seen from Table 3, the epoxy resin composition prepared from the active diluent without polyurethane modification has a lower tensile strength, and the tensile elongation at break is much lower than that of the epoxy resin composition prepared in Example 1, thus proving that the epoxy resin composition prepared from the active diluent after polyurethane modification has significantly improved tensile strength and elongation at break.

[0101] Comparative Example 6 uses hexamethylene-1,6-diisocyanate to modify neopentyl glycol diglycidyl ether, and the tensile strength is almost the same as that of the epoxy resin composition prepared in Example 1, but it greatly reduces the tensile elongation at break while improving the tensile strength, so it is best to use H6XDI to modify the active diluent.

[0102] II. The tensile properties of the filled casting were detected, and the detection method was as follows:

[0103] The filled casting was first prepared, and the components of the filled casting are shown in Table 8. The experiment was divided into an experimental group and a control group to detect the influence of different A components on the properties of the prepared filled casting.

[0104] Table 8. Composition of the filled casting

[0105]

[0106] The preparation method comprises: the preparation method of the experimental group and the control group is the same, that is, the above-mentioned components are three-roll ground to a fineness of less than 30 microns, then defoamed by a homogenizer, and then cast into an open mold coated with a release agent and preheated to 70 DEG C, further defoamed by oscillation, and then covered with a release film on the surface of the mold. Then, a flat plate is used to scrape the mold in the direction of the mold to squeeze out the excess glue, and a cast body containing pigments and fillers is prepared. The curing conditions for detection are: 70 DEG C / 16h, and then the mechanical property test is carried out after adjusting the temperature and humidity, and the detection results are shown in Table 9 below.

[0107] Table 9. Tensile property test of cast body containing pigments and fillers

[0108]

[0109] Conclusion: According to Table 5, it can be obtained that the cast body prepared by the experimental group has better tensile strength and better elongation at break, and it can be obtained that the epoxy resin composition prepared by the present application overcomes the defects of the existing active diluent, improves the breaking strength, and also realizes not reducing the tensile strength.

[0110] In summary: by modifying the active diluent with polyurethane, the present application overcomes the shortcomings of the traditional active diluent, that is, the addition amount exceeds a certain range, which will greatly reduce the performance of the cured product. Not only does it not significantly reduce the tensile strength, but it also improves the elongation at break and the bonding strength of the cured product, thereby meeting the requirements of pipeline repair coatings for strength and elongation.

[0111] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A high-elongation epoxy resin composition for oil pipeline repair coating, characterized in that, The epoxy resin composition is composed of component A and component B mixed in a weight ratio of 3:1; Component A comprises the following raw materials in parts by weight: 60-80 parts polyurethane modified epoxy resin, 5-15 parts polyether modified epoxy resin, 15-25 parts polyurethane modified reactive diluent; Component B comprises the following raw materials by weight percentage: 10-90% polyetheramine and 10-90% polyamide; The polyurethane-modified reactive diluent is prepared by modifying an reactive diluent with an oxazolidinone, and the polyurethane-modified reactive diluent is a liquid.

2. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 1, characterized in that, The polyurethane-modified reactive diluent is prepared by the following method: The catalyst and hydrogenated phenyl dimethyl diisocyanate were added sequentially to the active diluent, and the mixture was stirred at a constant temperature under a protective atmosphere to carry out the oxazolidinone modification reaction and obtain the reaction solution. During the constant temperature stirring process, the isocyanate group content of the reaction solution is monitored. When the isocyanate group content of the reaction solution is ≤0.1%, heating is stopped, and the polyurethane modified reactive diluent is obtained after cooling.

3. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 2, characterized in that: The molar ratio of the hydrogenated dimethyl phthalate to the reactive diluent is 1:(3-6).

4. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 2, characterized in that: The constant temperature stirring is 130-180℃, and the time is 2-5 hours.

5. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 2, characterized in that: The active diluent is selected from any one of neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and hexanediol diglycidyl ether.

6. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 2, characterized in that: The catalyst is selected from any one of 1-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, triphenylphosphine series, and tertiary amines, and the catalyst accounts for 0.01%-0.5% of the total mass of the active diluent and the hydrogenated phenyl dimethyl diisocyanate.

7. The high elongation epoxy resin composition for oil pipeline repair coating according to any one of claims 1-6, characterized in that, The preparation method of component A includes: The polyurethane-modified epoxy resin is heated and stirred, and then the polyether-modified epoxy resin and the polyurethane-modified reactive diluent are added to the polyurethane-modified epoxy resin in sequence. After stirring and filtering, component A is obtained.

8. The high elongation epoxy resin composition for oil pipeline repair coating according to claim 7, characterized in that: The heating and stirring temperature is 60-100℃, and the stirring time during stirring and filtering is 20-40 minutes.

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