A light-cured resin capable of thickening, and a preparation method and application thereof

Abstract

The present application relates to the technical field of high polymer materials, in particular to a thickening light-cured resin, a preparation method and application thereof, the preparation raw materials include, by weight fraction, phenolic aldehyde epoxy vinyl ester resin 60-80 parts, isocyanate 1-3 parts, acid anhydride 1-5 parts, polyhydric alcohol 2-8 parts, photoinitiator 0.2-2 parts, crosslinking monomer 10-30 parts, toughening agent 5-10 parts, and the Tg value of the phenolic aldehyde epoxy vinyl ester resin is 170-200 DEG C. The thickening light-cured resin provided by the present application has excellent wet heat resistance, can meet the long-term wet heat use conditions of the heat supply pipeline, the strength retention rate of the composite material made of the thickening light-cured resin and glass fiber cloth is more than 50% at 150 DEG C, and more reliable technical support is provided for the safe and stable operation of the heat supply system.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a thickening photocurable resin, its preparation method, and its applications. Background Technology

[0002] As the total length of heating pipelines continues to increase, some early-laid heating pipelines are constantly experiencing problems such as corrosion, aging, and damage due to years of disrepair and limitations in technical capabilities, resulting in frequent serious problems such as "running, leaking, dripping, and overflowing" in heating pipelines.

[0003] Currently, the main method for repairing thermal pipelines without excavation, both domestically and internationally, is the use of epoxy resin as the primary material for flexible hose repair. This is achieved primarily through steam curing to solidify the epoxy resin and shape the repair hose. For example, Chinese invention patent application CN101747491A provides a rapid-thickening vinyl ester resin, whose epoxy resin is bisphenol A type epoxy resin 1000.

[0004] However, epoxy resin thermosetting systems still have several drawbacks when repairing thermal pipelines: 1. When repairing large-diameter (≥800mm) long-distance thermal pipelines, the steam temperature introduced into the pipeline by the steam curing vehicle is difficult to exceed 90℃. The Tg (glass transition temperature) of epoxy resin is related to the curing temperature; the higher the curing temperature, the higher the Tg. Epoxy resins that can cure at 90℃ rarely achieve a Tg of 150℃ after curing, thus posing a risk of insufficient heat resistance. 2. Epoxy resins generally have a higher water absorption rate than vinyl ester resins, and their water resistance, especially against salty and chlorinated water sources, is worse than that of vinyl esters. Therefore, there is a certain risk in terms of the service life after repairing heating pipelines. 3. Repairing epoxy systems generally requires a steam boiler to provide the necessary temperature. Steam boilers are pressure equipment and their operation is limited. Furthermore, to ensure complete curing of the epoxy resin, the heating time needs to be extended, typically requiring more than ten hours, which can easily cause traffic congestion and other inconveniences. Summary of the Invention

[0005] To address the problems in the prior art, the first aspect of the present invention provides a thickening photocurable resin, wherein the raw materials for preparation, by weight, comprise:

[0006] 60-80 parts of phenolic epoxy vinyl ester resin;

[0007] 1-3 parts isocyanate;

[0008] 1-5 parts of acid anhydride;

[0009] 2-8 parts of polyols;

[0010] Photoinitiator 0.2~2 parts;

[0011] 10-30 parts of crosslinking monomer;

[0012] 5-10 parts toughening agent;

[0013] The Tg value of the phenolic epoxy vinyl ester resin is 170-200℃.

[0014] Currently, trenchless repair of thermal pipelines mainly relies on steam curing to solidify epoxy resin, thus shaping the repair hose. However, existing epoxy resin systems pose a risk of insufficient heat resistance after curing. The thickening photocurable resin provided by this invention uses phenolic epoxy vinyl ester resin as its main component. Through the synergistic crosslinking reaction of isocyanate, acid anhydride, and crosslinking monomers, the crosslinking point density is increased, forming a high-density rigid network structure that inhibits the thermal motion of molecular chains, thereby significantly improving Tg and high-temperature strength retention. Furthermore, the isocyanate in the system reacts with polyols to generate NCO-containing prepolymers, which then react with acid anhydrides to introduce carboxyl groups. Simultaneously, the isocyanate grafts onto the polyols to provide molecular weight and branching degree of the molecular structure, thereby enabling the resin to thicken and further enhancing its applicability in heating pipeline repair.

[0015] In some typical embodiments, the phenolic epoxy vinyl ester resin is designated as MFE 780.

[0016] In some embodiments, the isocyanate includes at least one of TDI, MDI, HMDI and IPDI.

[0017] In some embodiments, the anhydride includes at least one of maleic anhydride and phthalic anhydride.

[0018] In some typical embodiments, the anhydride is maleic anhydride.

[0019] In some embodiments, the polyol includes at least one of polyester polyol and polyether polyol.

[0020] Optionally, the polyester polyol includes a polycarbonate polyol; in some typical embodiments, the polycarbonate polyol includes a polycarbonate diol.

[0021] In some embodiments, the photoinitiator is selected from one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl ethyl ketone, 2,4-dihydroxybenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone.

[0022] Optionally, the photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, benzophenone, and isopropylthioxanthrone.

[0023] In some embodiments, the photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and 1-hydroxycyclohexylphenyl ketone.

[0024] In some embodiments, the mass ratio of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide to 1-hydroxycyclohexylphenyl ketone is (0.1~0.3):(0.1~0.3).

[0025] In some embodiments, the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropanone.

[0026] In some embodiments, the mass ratio of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide to 2-hydroxy-2-methyl-1-phenylpropanone is (1~3):(1~3).

[0027] In some embodiments, the crosslinking monomer includes one or more of styrene, vinyltoluene, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, lauryl methacrylate, trimethylolpropane triacrylate, triallyl cyanurate, tri(methacrylate)trimethylolpropane, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate.

[0028] Optionally, the crosslinking monomers are styrene, pentaerythritol triacrylate, and tri(methacrylate)trimethylolpropane ester.

[0029] Optionally, the mass ratio of styrene, pentaerythritol triacrylate, and tri(methacrylate)trimethylolpropane is (7~9):(2~2.5):(1~3). For example, 7:2:1, 7:2.5:2, 8:2:3, 9:2.5:2, etc., or any value within the range of (7~9):(2~2.5):(1~3).

[0030] Optionally, the crosslinking monomer is styrene, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate.

[0031] Optionally, the mass ratio of styrene, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate is (6~14):(3~8):(3~8). For example, 7:3.2:4, 7:3:3, 7:3.3:4, 14:8:8, etc., or any value within the range of (6~14):(3~8):(3~8).

[0032] In this invention, the selection of crosslinking monomers has a significant impact on the performance of thickenable photocurable resins. Different crosslinking monomers have different chemical structures and reactivity, and their interaction with components such as phenolic epoxy vinyl ester resin, isocyanate, and acid anhydride determines the crosslinking density, network structure, and final performance of the resin.

[0033] Styrene, a commonly used crosslinking monomer, possesses excellent solubility and reactivity, enabling it to form stable copolymer networks with other monomers. It can reduce resin viscosity and improve resin flowability, facilitating construction operations during heating pipeline repair. Simultaneously, the addition of styrene can also increase the resin's hardness and rigidity, enhancing the wear resistance and impact resistance of the repair material.

[0034] Multifunctional acrylate crosslinking monomers such as pentaerythritol triacrylate and tris(methacrylate)trimethylolpropane ester possess high reactivity and crosslinking density. They can undergo crosslinking reactions with the double bonds in phenolic epoxy vinyl ester resins to form a three-dimensional network structure, thereby significantly improving the resin's heat resistance, chemical corrosion resistance, and mechanical properties. In heating pipeline repair, this high-density crosslinking network can effectively resist the erosion of high temperature, high pressure, and chemical media, extending the service life of the repair material.

[0035] Trimethylolpropane triacrylate and dipentaerythritol hexaacrylate are both highly reactive crosslinking monomers. Their molecular structures contain multiple acrylate groups, enabling them to form a tighter crosslinking network with other components. This crosslinking network not only improves the resin's heat resistance and mechanical properties but also enhances its flexibility and adhesion, allowing the repair material to better adhere to the inner wall of the heating pipe and improving the repair effect. The applicant found that when styrene, pentaerythritol triacrylate, and tri(methacrylate)trimethylolpropane are mixed in a mass ratio of (8-9):(2-2.5):(2-3), and when styrene, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate are mixed in a mass ratio of (6-7):(3-3.5):(3-4), the resin achieves a better balance in terms of heat resistance, flexibility, and adhesion.

[0036] In some embodiments, the toughening agent includes a rubber toughening agent.

[0037] In some embodiments, the rubber toughening agent includes at least one of Huntsman MX-154, LSE-103-30, and WSG-930.

[0038] A second aspect of the present invention provides a method for preparing a thickenable photocurable resin, comprising at least the following steps:

[0039] S1. Mixture 1 is obtained by stirring and mixing phenolic epoxy vinyl ester resin, isocyanate and polyol.

[0040] S2. Add acid anhydride to mixture 1 and stir to react to obtain mixture 2;

[0041] S3. Add crosslinking monomer, photoinitiator and toughening agent to the mixture 2 in sequence and stir until uniform to obtain the thickening photocurable resin.

[0042] In some embodiments, S1 includes: stirring and mixing phenolic epoxy vinyl ester resin and polyol, heating to 55-65°C, adding isocyanate dropwise and reacting for 2-4 hours, then heating to 70-80°C and reacting for 1-2 hours until the NCO value of the system is less than 0.1% to obtain mixture 1.

[0043] Optionally, the dripping time is 30-40 minutes.

[0044] In some embodiments, S2 includes: cooling the mixture 1 to 50-60°C, adding acid anhydride, and reacting at 50-60°C for 2-3 hours until the acid value reaches 20-30 mg KOH / g, to obtain the mixture 2.

[0045] A third aspect of the present invention provides the application of a thickening photocurable resin in the repair of heating pipelines.

[0046] Trenchless repair requires pre-injecting resin into the main pipe reinforced with glass fiber using a vacuum injection process. During the initial 2 hours of resin injection and immersion in the glass fiber, the resin viscosity should not exceed 10,000 cps. After injection, it is desirable to exceed 50,000 cps within 24 hours and approach 100,000 cps within 48 hours. The final viscosity should not exceed 1,000,000 cps; otherwise, the pressure will be insufficient when the air compressor blows the hose up during on-site construction.

[0047] Beneficial effects

[0048] 1. The thickening photocurable resin provided by this invention is based on phenolic epoxy vinyl ester resin. Through the synergistic crosslinking reaction of isocyanate, acid anhydride, and crosslinking monomers, the crosslinking point density is increased, forming a high-density rigid network structure, which inhibits the thermal motion of molecular chains, thereby significantly improving Tg and high-temperature strength retention. On the other hand, the isocyanate in the system reacts with polyol to generate an NCO-containing prepolymer, which then reacts with acid anhydride to introduce carboxyl groups. At the same time, the isocyanate grafts polyol to provide molecular weight and the degree of branching of molecular structure, thereby achieving the thickening of the resin.

[0049] 2. The photocurable resin provided by this invention can be thickened with magnesium oxide paste and can be rapidly photocured under ultraviolet light in the 365~420nm wavelength band. The glass transition temperature Tg can reach 180℃ and can withstand high temperatures of 80-150℃ for a long time. The composite material made of it and glass fiber cloth has a strength retention rate of more than 50% at 150℃. In the humid heat cycling aging test, its strength retention rate exceeds 85% after 1000h of double 85 (85% humidity and 85℃ temperature) test.

[0050] 3. This invention uses phenolic epoxy vinyl ester resin as the main component, which makes the prepared thickenable light-curable resin material have excellent resistance to damp heat and can meet the long-term damp heat use conditions of heating pipelines.

[0051] 4. The thickening UV-curable resin provided by this invention can be used in the repair of heating pipelines. The repair method is convenient, can be carried out at room temperature, and has rapid UV curing. Single-point curing only takes 10-20 minutes, which improves construction efficiency. Moreover, trenchless construction only requires excavating working pits at both ends, reducing the amount of earthwork (more than 80% less than traditional excavation). The UV curing time is short (100-meter section of pipeline can be completed in 1-2 days), and it can be quickly repaired during the off-heating period (such as summer), avoiding the impact on winter heating, and has a very good development prospect.

[0052] 5. This invention is applied to the repair of heating pipelines. The surface of the cured inner lining is smooth and resistant to corrosion from oxygen, chloride ions and sulfides in the heating medium. It is especially suitable for solving the problem of "oxygen corrosion" in steel pipelines and can effectively seal micro-cracks and pinholes, reducing the leakage rate. Attached Figure Description

[0053] Figure 1-3 The Tg curves are for the thickening photocurable resins provided in Example 1, Example 2, and Comparative Example 1, respectively.

[0054] Figure 4 The graph shows the viscosity of the sample after adding magnesium oxide paste in Example 2 over time. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Experimental methods not specifying specific conditions in the embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Reagents not specifying manufacturers are all commercially available conventional products.

[0056] Example 1

[0057] The first aspect of this example provides a thickening photocurable resin, the raw materials for which, by weight, are:

[0058] 60 parts of phenolic epoxy vinyl ester resin;

[0059] 1 part isocyanate;

[0060] 1 part acid anhydride;

[0061] Two parts of polyol;

[0062] 0.2 parts of photoinitiator;

[0063] 10 parts of crosslinking monomer;

[0064] 5 parts toughening agent.

[0065] The phenolic epoxy vinyl ester resin has a hydroxyl value of 146 mg KOH / g, a viscosity of 600 cps at 25℃, a Tg value of 170-200℃, and is model MFE 780, sourced from East China University of Science and Technology Huachang Polymer Co., Ltd.

[0066] The isocyanate is MDI, derived from BASF's 103C.

[0067] The acid anhydride is maleic anhydride.

[0068] The polyol is a polycarbonate diol with a molecular weight of 1000 and a hydroxyl value of 112 mgKOH / g.

[0069] The polycarbonate diol is polycarbonate 965 and comes from Tosoh (Shanghai) Polyurethane Co., Ltd.

[0070] The photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and 1-hydroxycyclohexylphenyl ketone in a mass ratio of 0.1:0.1.

[0071] The crosslinking monomers are styrene, pentaerythritol triacrylate and tri(methacrylate)trimethylolpropane ester, in a mass ratio of 7:2:1.

[0072] The toughening agent is WSG-930, which comes from Guangzhou Wanhua New Materials Technology Co., Ltd.

[0073] The second aspect of this example provides a method for preparing a thickening photocurable resin, comprising the following steps:

[0074] S1. Phenolic epoxy vinyl ester resin and polyol are stirred and mixed, and then heated to 60°C. Isocyanate is added dropwise, and the addition is completed within 30 minutes. The reaction is carried out for 2.5 hours, and then heated to 75°C and reacted for 1.5 hours until the NCO value of the system is less than 0.1% to obtain mixture 1.

[0075] S2. Cool the mixture 1 to 60°C, add acid anhydride, and react at 60°C for 2.5 hours until the acid value reaches 20~30 mgKOH / g and the reaction reaches the endpoint to obtain the mixture 2.

[0076] S3. Add crosslinking monomer and photoinitiator to the mixture 2 in sequence and stir for 1 hour. Then add toughening agent and continue stirring for 1 hour to obtain the thickening photocurable resin.

[0077] The third aspect of this example provides an application of a thickening light-curing resin in the repair of heating pipelines.

[0078] Example 2

[0079] The specific implementation method in this example is the same as in Example 1, except that, by weight, the raw materials include:

[0080] 80 parts of phenolic epoxy vinyl ester resin;

[0081] 3 parts isocyanate;

[0082] 5 parts of acid anhydride;

[0083] 8 parts of polyols;

[0084] Two parts of photoinitiator;

[0085] 30 parts of crosslinking monomer;

[0086] 10 parts toughening agent.

[0087] The isocyanate is HMDI, sourced from Wanhua Chemical Group Co., Ltd.

[0088] The acid anhydride is phthalic anhydride.

[0089] The photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropanone in a mass ratio of 1:1.

[0090] The styrene, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate are in a mass ratio of 14:8:8.

[0091] The toughening agent is Huntsman MX-154, sourced from Huntsman Advanced Materials (Shanghai) Co., Ltd.

[0092] Comparative Example 1

[0093] The specific implementation method in this example is the same as in Example 1, except that the phenolic epoxy vinyl ester resin has a Tg value of 150-160℃, is of type MFE W3, and comes from East China University of Science and Technology Huachang Polymer Co., Ltd.

[0094] Comparative Example 2

[0095] The specific implementation method in this example is the same as in Example 1, except that, by weight, the raw materials include:

[0096] 60 parts of phenolic epoxy vinyl ester resin;

[0097] 0.5 parts isocyanate;

[0098] 1 part acid anhydride;

[0099] Two parts of polyol;

[0100] 0.2 parts of photoinitiator;

[0101] 10 parts of crosslinking monomer;

[0102] 5 parts toughening agent.

[0103] Comparative Example 3

[0104] The specific implementation method in this example is the same as in Example 1, except that, by weight, the raw materials include:

[0105] 60 parts of phenolic epoxy vinyl ester resin;

[0106] 4 parts isocyanate;

[0107] 1 part acid anhydride;

[0108] Two parts of polyol;

[0109] 0.2 parts of photoinitiator;

[0110] 10 parts of crosslinking monomer;

[0111] 5 parts toughening agent.

[0112] Comparative Example 4

[0113] The specific implementation method in this example is the same as in Example 1, except that, by weight, the raw materials include:

[0114] 60 parts of phenolic epoxy vinyl ester resin;

[0115] 1 part isocyanate;

[0116] 1 part acid anhydride;

[0117] One part of polyol;

[0118] 0.2 parts of photoinitiator;

[0119] 10 parts of crosslinking monomer;

[0120] 5 parts toughening agent.

[0121] Comparative Example 5

[0122] The specific implementation method in this example is the same as in Example 1, except that, by weight, the raw materials include:

[0123] 60 parts of phenolic epoxy vinyl ester resin;

[0124] 1 part isocyanate;

[0125] 1 part acid anhydride;

[0126] 9 parts of polyols;

[0127] 0.2 parts of photoinitiator;

[0128] 10 parts of crosslinking monomer;

[0129] 5 parts toughening agent.

[0130] Performance testing

[0131] 1. The thickening photocurable resins prepared in Examples 1, 2, and Comparative Example 1 were subjected to irradiation with a mercury lamp in the 395-420 nm wavelength range. At a height of 25 cm between the lamp and the resin surface, the irradiation energy density obtained on the resin surface was ≥40 mw / cm². 2 Under the given conditions, a fully cured resin block was obtained after irradiation for 5 minutes. Its glass transition temperature (Tg) was measured using a DSC instrument. The test results are shown below. Figure 1-3 As can be seen from the figure, the Tg of the thickening photocurable resin provided by the present invention can reach up to 180°C; while the Tg of Comparative Example 1 is 125°C, which does not meet the safety requirements for use in heating pipelines.

[0132] 2. Thickening performance test:

[0133] 1) The thickening photocurable resin obtained in Example 2 was mixed with different proportions of magnesium oxide paste thickener MK25, and the thickening curves at 25°C were tested. The raw material composition of each sample is shown in Table 1:

[0134] Table 1

[0135]

[0136] The test results are shown in Table 2 and Figure 4 .

[0137] Table 2

[0138]

[0139] As can be seen from the table and figures above, the viscosity of samples with different proportions of magnesium oxide paste thickener MK 25 and samples with added deionized water all showed a significant increasing trend with increasing time. The thickening photocurable resin provided by this invention has excellent thickening properties, and the thickening speed and final viscosity can be controlled by adjusting the amount of magnesium oxide paste thickener and whether or not deionized water is added. This controllable thickening property gives the resin a significant advantage in practical applications such as heating pipeline repair, allowing for flexible adjustment of the resin viscosity according to different construction requirements and environmental conditions to achieve optimal construction results.

[0140] 2) Take 100 parts of the thickening light-curing resin obtained from Comparative Examples 2-5 respectively, add 1.8 parts by weight of magnesium oxide paste thickener MK 25, and test the thickening curve at 25℃. The test results are shown in Table 3.

[0141] Table 3

[0142]

[0143] As can be seen from Table 3, neither reducing nor increasing the amount of isocyanate and toughening resin in Comparative Examples 2-5 could meet the thickening requirements for the early stage of trenchless repair (the viscosity of the resin should be low, not exceeding 10,000 cps, during the initial 2 hours of grouting and impregnation of the glass fiber; after grouting, it should exceed 50,000 cps within 24 hours and approach 100,000 cps within 48 hours; the resin-coated hose should not easily flow and can be shipped; the final viscosity should not exceed 1,000,000 cps).

[0144] 3. By weight percentage, take 45% of the thickening photocurable resin prepared in Examples 1 and 2 and 55% of the glass fiber composite mat (WRM860-1600MM). Use a vacuum infusion process to impregnate the glass fiber composite mat with the thickening photocurable resin and cure it under a UV light source with a wavelength of 395nm for 10 minutes to obtain a UV-curable fiber reinforced composite material (FRP).

[0145] The energy density of the ultraviolet light source irradiating the surface of the photocurable adhesive is 40 mw / cm². 2 .

[0146] The fiberglass composite felt has a specification of 860g / m². 2The model number is WRM860-1600MM, and it comes from Zhejiang Hongming Fiberglass Products Co., Ltd.

[0147] The processing steps of the vacuum induction process include:

[0148] A1. Clean the mold, and then apply a release agent to the surface of the mold;

[0149] A2. Lay 12 layers of WRM860-1600MM glass fiber reinforcement material on the surface of the mold. After the reinforcement material is laid, use scissors to cut off the excess fiber.

[0150] A3. Cover the entire glass fiber reinforced material with the release cloth, leaving about 1mm extra at the edge of the glass fiber reinforced material;

[0151] A4. Lay a flow guide net on the surface of the release cloth, with the flow guide net about 3-5cm away from the glass fiber reinforced material, that is, the size of the flow guide net is slightly smaller than the glass fiber reinforced material;

[0152] A5. Place the solenoid in the corresponding position in the mold cavity according to the pre-designed flow channel as the resin flow channel and vacuum tube, and pass the silicone nozzle through the solenoid;

[0153] A6. After the pipeline is laid out, a vacuum bag film is laid on the surface. During the laying process, the middle section of the four sides is overlapped with sealing tape to form a raised shape to prevent the vacuum bag film from bridging.

[0154] A7. Insert the guide tube into the silicone connector of the resin and the vacuum end, and seal it with sealant;

[0155] A8. Clamp the inlet tube of the UV-curing adhesive with a pipe clamp to ensure a sealed environment. Turn on the vacuum pump to remove the air from the vacuum bag, then temporarily turn off the vacuum pump and clamp the inlet tube of the vacuum pump. After half an hour, ensure that the vacuum pump pointer does not change.

[0156] A9. Keep the vacuum pump running and gently unscrew the clamp on the UV-curable adhesive delivery tube. The UV-curable adhesive will be drawn into the delivery tube and begin to flow. When the UV-curable adhesive reaches the UV-curable adhesive collector, close the delivery tube at the inlet end with the clamp to stop the flow.

[0157] The tensile strength, tensile modulus, flexural strength, and flexural modulus of the prepared FRP material were tested at 23℃, 130℃, and 150℃, respectively, in accordance with GB / T 2567-2021. The test results are shown in Table 4.

[0158] Table 4

[0159]

[0160] As can be seen from the table above, the composite material made of the thickening photocurable resin and glass fiber cloth prepared in this invention retains more than 50% of its strength at 150°C.

[0161] 4. Damp heat cycling aging test:

[0162] UV-cured FRP materials were prepared according to the method in Test 3 for Examples 1 and 2, respectively, and placed in a damp heat aging chamber for 1000h of double 85 (damp heat aging cycle of 85% humidity and 85℃ temperature) test (test standard GB / T 2567-2021). The test results are shown in Table 5.

[0163] Table 5

[0164]

[0165] Test results show that the FRP material made by UV curing of thickening light-curing resin retains 85% of its flexural strength after 1000h of damp heat aging, demonstrating excellent resistance to damp heat aging.

[0166] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thickening photocurable resin, characterized in that, The raw materials for preparation, by weight, include: 60-80 parts of phenolic epoxy vinyl ester resin; 1-3 parts isocyanate; 1-5 parts of acid anhydride; 2-8 parts of polyol; Photoinitiator 0.2~2 parts; 10-30 parts of crosslinking monomer; 5-10 parts toughening agent; The Tg value of the phenolic epoxy vinyl ester resin is 170-200℃; The crosslinking monomer is styrene, trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, or styrene, pentaerythritol triacrylate and tri(methacrylate)trimethylolpropane acrylate. The mass ratio of styrene, trimethylolpropane triacrylate and dipentaerythritol hexaacrylate is (6~14):(3~8):(3~8); The mass ratio of styrene, pentaerythritol triacrylate and tri(methacrylate) trimethylolpropane is (7~9):(2~2.5):(1~3); The phenolic epoxy vinyl ester resin is model MFE 780; The acid anhydride includes at least one of maleic anhydride and phthalic anhydride; The isocyanate includes MDI or HMDI; The polyols include polycarbonate diols.

2. The thickening photocurable resin according to claim 1, characterized in that, The photoinitiator is selected from one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl ethyl ketone, 2,4-dihydroxybenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone.

3. The thickening photocurable resin according to claim 1, characterized in that, The photoinitiator includes at least one of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, benzophenone, and isopropylthioxanthrone.

4. The thickening photocurable resin according to claim 1, characterized in that, The toughening agent includes a rubber toughening agent.

5. A method for preparing a thickening photocurable resin according to any one of claims 1-4, characterized in that, At least the following steps are included: S1. Mixture 1 is obtained by stirring and mixing phenolic epoxy vinyl ester resin, isocyanate and polyol. S2. Add acid anhydride to mixture 1 and stir to react to obtain mixture 2; S3. Add crosslinking monomer, photoinitiator and toughening agent to the mixture 2 in sequence and stir until uniform to obtain the thickening photocurable resin.

6. The application of a thickening photocurable resin according to any one of claims 1-4 in the repair of heating pipelines.

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