Resin material for thermally-initiated front-end polymerization reaction and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer material engineering, and particularly relates to a resin material for thermally-initiated front-end polymerization reaction and a preparation method thereof. The resin material comprises the following components in parts by weight: 100 parts of resin, 5-20 parts of a curing agent, 1-5 parts of an accelerant, 1-5 parts of alkanol, 5-20 parts of a molecular sieve and 5-15 parts of paraffin. The resin material belongs to a latent curing type, can be stored for more than 30 days at the temperature of 25 DEG C, can be heated by an electric soldering iron to initiate a front-end polymerization reaction during use, has controllability, does not need to be continuously heated to maintain the reaction in the curing process, is relatively short in reaction time and low in energy consumption, and has a good application prospect in the fields of rapid bonding, plate repairing, pipeline leaking stoppage and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material engineering, and in particular relates to a resin material for heat-initiated front-end polymerization reaction and a preparation method thereof. Background Art

[0002] Front-end polymerization is a reaction mode that converts monomers into polymers by moving through local reaction areas. It has attracted widespread attention from researchers for its rapid and energy-saving characteristics. Most front-end polymerization systems with synthetic resins as reactive monomers have strong reactivity and high exothermic temperatures, resulting in short storage time. In actual application, inhibitors need to be added or temporary preparation is required at the construction site, and controllability is poor. At the same time, the high exothermic temperature poses certain safety hazards. Therefore, in actual application, latent resin curing agents need to be used to extend the operation time and increase controllability.

[0003] At present, most of the latent resin curing agents on the market are mainly chemically modified, and the active groups in the curing agent molecules are blocked and passivated to reduce their reactivity, such as boron trifluoride ethylamine complex. However, the reduction in reactivity means that it is difficult to trigger the front-end polymerization reaction, and continuous heating or light is required to completely cure the resin, which increases construction time and energy consumption. Therefore, it is of great practical significance to develop a resin material that can be stored for a long time and can trigger the front-end polymerization reaction, and it has good application prospects in the fields of rapid bonding, plate repair, and pipeline plugging. Summary of the invention

[0004] The purpose of the present invention is to provide a resin material for heat-induced front-end polymerization reaction and a preparation method thereof. The resin material can be stored for more than 30 days at 25°C, so it can be prepared and stored in the factory in advance. When used, it only needs to be heated by an electric soldering iron to induce the front-end polymerization reaction, and the polymerization reaction can be maintained by relying on the self-heating of the reaction until it is completely cured, which effectively overcomes the shortcomings of the prior art.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] A resin material for heat-initiated front-end polymerization reaction comprises the following components by weight: 100 parts of resin, 5-20 parts of curing agent, 1-5 parts of accelerator, 1-5 parts of alkanol, 5-20 parts of molecular sieve and 5-15 parts of paraffin.

[0007] In the present invention, the reason for adding molecular sieve is that the peculiar porous structure of molecular sieve has very strong adsorption, and curing agent molecules can be adsorbed inside it to form a core-shell structure. Meanwhile, the thermal expansibility of molecular sieve can release curing agent from molecular sieve at high temperature to participate in curing reaction. In addition, molecular sieve, as a kind of aluminosilicate inorganic material, can play a certain reinforcing role in resin. Adding alkanol as the adhesive of molecular sieve, due to its low melting point and hard texture, adding a small amount of alkanol in molecular sieve can be used to prepare particles of different particle sizes, and the influence on reaction activity is small. The purpose of adding paraffin is to carry out surface treatment to the latent curing agent particles prepared, further prolonging its storage time. In addition, paraffin can play a plasticizing effect in resin, improves its toughness and surface smoothness.

[0008] Preferably, the resin is selected from one or more of bisphenol A epoxy resin, novolac epoxy resin and bisphenol A epoxy vinyl resin.

[0009] More preferably, the epoxy value of the bisphenol A epoxy resin and the novolac epoxy resin is greater than 0.4.

[0010] Preferably, when the resin is bisphenol A epoxy resin and / or phenolic epoxy resin, the curing agent is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine;

[0011] When the resin is bisphenol A epoxy vinyl resin, the curing agent is selected from one or more of cyclohexanone peroxide, dibenzoyl peroxide, and methyl ethyl ketone peroxide.

[0012] The present invention selects aliphatic amine as the curing agent of epoxy resin and peroxide as the curing agent of vinyl resin because their higher reaction activity can induce front-end polymerization reaction.

[0013] Preferably, when the resin is a bisphenol A epoxy resin and / or a novolac epoxy resin, the accelerator is selected from one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine, and resorcinol;

[0014] When the resin is bisphenol A epoxy resin, the accelerator is selected from one or more of cobalt naphthenate, cobalt isooctanoate, and N,N-dimethylaniline.

[0015] The present invention preferably compounded specific accelerators for different resin types, which can further reduce the reaction energy barrier and maintain the front-end polymerization reaction.

[0016] Preferably, the alkanol is selected from one or more of n-hexadecanol, n-octadecyl alcohol, and n-eicosanol. Studies have shown that compared with other alkanols, the alkanols have a melting point between 40 and 70° C., are solid at room temperature, and have little effect on the reactivity of the front-end polymerization system.

[0017] Preferably, the molecular sieve is selected from one or more of natural zeolite powder, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, and 13X molecular sieve.

[0018] Preferably, the paraffin wax is fully refined or semi-refined paraffin wax with a melting point between 50-60°C.

[0019] The present invention also provides a method for preparing the above-mentioned resin material for heat-induced front-end polymerization reaction, comprising the following steps:

[0020] (1) adding a curing agent and molecular sieve powder into a blender and mixing them evenly, and further drying and cooling them to obtain a mixture A1;

[0021] (2) melting alkanol into a liquid state, adding the mixture A1 to the liquid alkanol in multiple portions, and continuously stirring until the mixture is uniformly mixed, cooling the obtained mixture into a solid state, and then cutting it into particles with a particle size of 1-2 mm to obtain a mixture A2;

[0022] (3) Melting paraffin into liquid form and adding it to a sprayer, adding the mixture A2 to a swinging pelletizer to allow it to tumble continuously, and spraying the liquid paraffin on the surface of the mixture A2 using a sprayer, spraying it evenly and then cooling it to obtain a mixture A3;

[0023] (4) The resin, the accelerator and the mixture A3 are mixed uniformly to obtain the resin material for the thermally initiated front-end polymerization reaction.

[0024] Preferably, in step (1), when the curing agent is solid, it is first dissolved in an organic solvent and then added to the mixer.

[0025] Preferably, in step (1), the drying is carried out in a vacuum drying oven.

[0026] Preferably, in step (2), the alkanol is melted into a liquid state at 60-80°C.

[0027] Preferably, in step (3), the paraffin wax is melted into a liquid state at 60-70°C.

[0028] The beneficial effects of the present invention are at least:

[0029] 1) The resin material for heat-induced front-end polymerization provided by the present invention is a latent curing type, has a room temperature storage period of more than 30 days, can be prepared and stored in the factory in advance, and is heated to induce curing reaction when used, which is easy to operate and has good controllability;

[0030] 2) The resin material of the heat-initiated front-end polymerization reaction provided by the present invention is cured by the front-end polymerization reaction, which can be initiated by heating at a single point with an electric soldering iron. After initiation, the heat source is removed, and the reaction can be maintained until it is completely cured by relying on the self-exothermic reaction, which is energy-saving and efficient;

[0031] 3) The resin material of the heat-induced front-end polymerization reaction provided by the present invention has good mechanical properties after curing, with a tensile strength of not less than 80MPa, a flexural strength of not less than 100MPa, and a flexural modulus of not less than 3000MPa, and has good application prospects in the fields of rapid bonding, plate repair, and pipeline plugging;

[0032] 4) The resin material for heat-initiated front-end polymerization provided by the present invention is preferably compounded with specific curing agents and accelerators for different resin types. Its high reactivity can initiate the front-end polymerization reaction, while reducing the reaction energy barrier to maintain the front-end polymerization reaction. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is described clearly and completely below. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the field or the product instructions are used.

[0034] In the following examples, information of each reagent used is shown in Table 1.

[0035] Table 1 Information of reagents used in the examples

[0036] Reagents Manufacturer / Model Bisphenol A epoxy resin Sinopec Baling Branch / E-44 Bisphenol A epoxy vinyl resin Nan Ya Plastics Industrial Co., Ltd. / V1A01 Natural zeolite powder Henan Huanyu Molecular Sieve Co., Ltd. / Zeolite Activated Powder 3A molecular sieve Henan Huanyu Molecular Sieve Co., Ltd. / 3A Molecular Sieve

[0037] Example 1

[0038] A resin material for heat-initiated front-end polymerization reaction comprises the following components by weight: 100 parts of bisphenol A epoxy resin, 12 parts of diethylenetriamine, 2 parts of 2,4,6-tris(dimethylaminomethyl)phenol, 2 parts of n-octadecyl alcohol, 12 parts of natural zeolite powder, and 8 parts of paraffin. The preparation method of the material comprises the following steps:

[0039] (1) adding diethylenetriamine and natural zeolite powder in a proportion into a mixer, mixing them thoroughly and evenly, placing them in a vacuum drying oven to dry, and then cooling them into solid powder for later use;

[0040] (2) melting n-octadecyl alcohol into a liquid at 75° C., then adding the above powder evenly in three times (each time with an interval of 30 seconds), and continuously stirring until fully mixed, cooling the mixture into a solid at room temperature, and then cutting it into particles with a particle size of 1-2 mm using a cutting tool for later use;

[0041] (3) Melting paraffin into liquid at 60° C. and adding it into a sprayer, adding the above-mentioned particles into a swinging particle machine to make them tumble continuously, and spraying liquid paraffin on the surface of the particles by using a sprayer, and cooling the particles at room temperature to form solid particles for use after the particles are evenly sprayed;

[0042] (4) Bisphenol A epoxy resin, 2,4,6-tris(dimethylaminomethyl)phenol and the above particles are mixed uniformly at room temperature in proportion to obtain a resin material for heat-induced front-end polymerization reaction.

[0043] Resin storage: Pour the prepared resin material into a sealed container and store it away from light at 25°C. Take small samples regularly every day for testing to check whether the resin has solidified. The test results are shown in Table 2.

[0044] Table 2 Epoxy resin storage time test results

[0045] Storage time / day 1-10 11-20 21-30 31-40 Test results Uncured Uncured Uncured Partially cured

[0046] Resin curing: Pour the prepared resin material into a rectangular container, use an electric soldering iron (about 150°C) to heat one end to initiate, and the front end polymerization reaction begins after heating for 3 minutes. Then remove the heat source, and the reaction end face steadily advances to the other end under the action of self-exothermicity, with a forward speed of about 8cm / min. During the reaction, the temperature of the front end face is maintained at about 100°C until the whole is completely cured.

[0047] Performance test: The mechanical properties of the cured resin were tested in accordance with GB / T 2567-2021 “Test method for properties of resin castings”. The test results are shown in Table 3.

[0048] Table 3 Test results of mechanical properties of epoxy resin

[0049] project Tensile strength / MPa Bending strength / MPa Flexural modulus / MPa Test results 96 133 3987

[0050] Example 2

[0051] A resin material for heat-initiated front-end polymerization reaction, comprising the following components by weight: 100 parts of bisphenol A epoxy vinyl resin, 8 parts of cyclohexanone peroxide, 2 parts of N,N-dimethylaniline, 2 parts of hexadecanol, 8 parts of 3A molecular sieve powder, and 5 parts of paraffin. The preparation method of the material comprises the following steps:

[0052] (1) dissolving cyclohexanone peroxide in ethanol, then adding the ethanol solution of cyclohexanone peroxide and 3A molecular sieve powder into a blender, mixing them thoroughly and evenly, placing them in a vacuum drying oven for drying, and then cooling them into solid powder for standby use;

[0053] (2) Melting hexadecanol into liquid at 65° C., then adding the above powder evenly in 3 times (each time with an interval of 30 seconds), and continuously stirring until fully mixed, cooling the mixture into solid at room temperature, and then cutting it into particles with a particle size of 1-2 mm using a cutting tool for later use;

[0054] (3) Melting paraffin into liquid at 60° C. and adding it into a sprayer, adding the above-mentioned particles into a swinging particle machine to make them tumble continuously, and spraying liquid paraffin on the surface of the particles by using a sprayer, and cooling the particles at room temperature to form solid particles for use after the particles are evenly sprayed;

[0055] (4) Bisphenol A epoxy vinyl resin, N,N-dimethylaniline and the above particles are mixed uniformly in proportion at room temperature to obtain a resin material for heat-induced front-end polymerization reaction.

[0056] Resin storage: Pour the prepared resin material into a sealed container and store it at 25°C away from light. Take small samples regularly every day for testing to check whether the resin has solidified. The test results are shown in Table 4.

[0057] Table 4 Vinyl resin storage time test results

[0058] Storage time / day 1-10 11-20 21-30 31-40 41-50 Test results Uncured Uncured Uncured Uncured Partially cured

[0059] Resin curing: Pour the above resin into a rectangular container and use an electric soldering iron (about 150°C) to heat one end to initiate the polymerization reaction. After heating for 5 minutes, the heat source is removed and the reaction end surface is steadily pushed toward the other end under the action of self-exothermicity. The forward speed is about 5 cm / min. During the reaction, the temperature of the front end surface is maintained at about 85°C until the whole is completely cured.

[0060] Performance test: The mechanical properties of the cured resin were tested in accordance with GB / T 2567-2021 “Test method for properties of resin castings”. The test results are shown in Table 5.

[0061] Table 5 Test results of mechanical properties of vinyl resin

[0062] project Tensile strength / MPa Bending strength / MPa Flexural modulus / MPa Test results 84 115 3277

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resin material for thermally initiated front-end polymerization reaction, characterized in that: The invention comprises the following components in parts by weight: 100 parts of resin, 5-20 parts of curing agent, 1-5 parts of accelerator, 1-5 parts of alkanol, 5-20 parts of molecular sieve and 5-15 parts of paraffin.

2. The resin material for thermally initiated front-end polymerization according to claim 1, characterized in that: The resin is selected from one or more of bisphenol A epoxy resin, novolac epoxy resin and bisphenol A epoxy vinyl resin.

3. The resin material for thermally initiated front-end polymerization according to claim 1 or 2, characterized in that: When the resin is bisphenol A epoxy resin and / or phenolic epoxy resin, the curing agent is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine; When the resin is bisphenol A epoxy vinyl resin, the curing agent is selected from one or more of cyclohexanone peroxide, dibenzoyl peroxide, and methyl ethyl ketone peroxide.

4. The resin material for thermally initiated front-end polymerization according to claim 1 or 2, characterized in that: When the resin is a bisphenol A epoxy resin and / or a novolac epoxy resin, the accelerator is selected from one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine, and resorcinol; When the resin is bisphenol A epoxy resin, the accelerator is selected from one or more of cobalt naphthenate, cobalt isooctanoate, and N,N-dimethylaniline.

5. The resin material for thermally initiated front-end polymerization according to claim 1 or 2, characterized in that: The alkanol is selected from one or more of hexadecanol, n-octadecyl alcohol, and n-eicosanol.

6. The resin material for thermally initiated front-end polymerization according to claim 1 or 2, characterized in that: The molecular sieve is selected from one or more of natural zeolite powder, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve and 13X molecular sieve.

7. The resin material for thermally initiated front-end polymerization according to claim 1 or 2, characterized in that: The paraffin wax is fully refined or semi-refined paraffin wax with a melting point between 50-60°C.

8. The method for preparing a resin material by heat-induced front-end polymerization according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) adding a curing agent and molecular sieve powder into a blender and mixing them evenly, and further drying and cooling them to obtain a mixture A1; (2) melting alkanol into a liquid state, adding the mixture A1 to the liquid alkanol in multiple portions, and continuously stirring until the mixture is uniformly mixed, cooling the obtained mixture into a solid state, and then cutting it into particles with a particle size of 1-2 mm to obtain a mixture A2; (3) Melting paraffin into liquid form and adding it to a sprayer, adding the mixture A2 to a swinging pelletizer to allow it to tumble continuously, and spraying the liquid paraffin on the surface of the mixture A2 using a sprayer, spraying it evenly and then cooling it to obtain a mixture A3; (4) The resin, the accelerator and the mixture A3 are mixed uniformly to obtain the resin material for the thermally initiated front-end polymerization reaction.

9. The preparation method according to claim 8, characterized in that: In step (2), the alkanol is melted into a liquid state at 60-80° C.; And / or, in step (3), the paraffin wax is melted into a liquid state at 60-70°C.

10. The preparation method according to claim 8 or 9, characterized in that: In step (1), when the curing agent is solid, it is first dissolved in an organic solvent and then added to the mixer.