Preparation method and application of plasticizer for paste resin

Abstract

The invention relates to the field of paste resin plasticizers, in particular to a preparation method and application of a plasticizer for paste resin, and the preparation method of the plasticizer comprises the following steps: (1) carrying out ultrasonic treatment and centrifugal drying on a carbon nano tube through a silane coupling agent ethanol solution to obtain a pretreated nano material with amino groups on the surface; (2) dispersing an environment-friendly plasticizer, the pretreated nano material and glycidyl methacrylate through gradient heating and gradient shearing to form uniform pre-polymerized slurry; (3) initiating a polymerization reaction under the protection of nitrogen, and constructing a three-dimensional network structure through epoxy group ring opening and free radical grafting; and (4) filtering and devolatilizing to obtain a plasticizer finished product. According to the method, nano material dispersion and chemical anchoring processes are optimized, so that the paste resin prepared by using the plasticizer has excellent heat resistance, high insulativity and mechanical strength, and can be widely applied to the high-end fields of medical products, high-temperature cables, new energy batteries and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paste resin plasticizer, in particular to a paste resin plasticizer preparation method and application thereof. BACKGROUND

[0002] As an important polymer material, the performance of paste resin is highly dependent on the selection and preparation process of plasticizer. Although traditional plasticizers (such as phthalate esters) can improve the flexibility and processability of the resin, they have poor environmental performance, insufficient heat resistance, and easy migration. In recent years, environmentally friendly plasticizers have gradually become a research hotspot, but they still have limitations in terms of high temperature resistance, chemical resistance, and mechanical properties, which makes it difficult for paste resin prepared by using traditional plasticizers to adapt to complex working environments, and thus cannot be applied to high-end technical fields.

[0003] It has been found that the introduction of nanomaterials into plasticizers can significantly improve the electrical insulation and mechanical properties of paste resin, but the introduced nanomaterial particles tend to agglomerate and disperse unevenly, making it difficult to fully utilize their functions. SUMMARY

[0004] To solve the aforementioned technical problems, the present application provides a paste resin plasticizer preparation method, which optimizes the dispersion and chemical anchoring process of nanomaterials to solve the problem of poor comprehensive performance of paste resin caused by easy agglomeration of nanomaterials. The technical solution is as follows.

[0005] The present application provides a paste resin plasticizer preparation method, which comprises the following steps: Step 1: Soak carbon nanotubes in an ethanol solution containing a silane coupling agent, perform ultrasonic treatment and centrifugal drying to obtain pretreated nanomaterials; Step 2: Add environmentally friendly plasticizers, pretreated nanomaterials, and functional monomers containing epoxy groups into a dispersion kettle, and perform pre-dispersion treatment by gradient heating and gradient shearing to obtain a raw material mixture; Step 3: Transfer the raw material mixture to a reaction kettle, add an initiator, and perform polymerization under nitrogen protection to obtain a plasticizer crude product; Step 4: Filter and devolatilize the plasticizer crude product to obtain a plasticizer finished product; Wherein, the environmentally friendly plasticizer is dioctyl terephthalate or trioctyl trimellitate, or a mixture of the two in any proportion, and the functional monomer containing epoxy groups is glycidyl methacrylate.

[0006] Preferably, the initiator is azobisisobutyronitrile, and the addition amount of the initiator is 3% to 6% of the mass of the pretreated nanomaterials.

[0007] Preferably, in the step 1, the mass concentration of the ethanol solution is 50% to 60%, the frequency of the ultrasonic treatment is 40 kHz to 45 kHz, and the time is 30 min to 40 min; the vacuum degree of the centrifugal drying is 0.05 MPa to 0.1 MPa, the temperature is 55°C to 75°C, and the rotation speed is 2000 r / min to 4000 r / min.

[0008] Preferably, in the step 2, the mass ratio of the environment-friendly plasticizer, the pretreated nanomaterial and the functional monomer containing epoxy group is 80 to 95: 1 to 5: 3 to 8.

[0009] Preferably, in the step 2, the gradient temperature rising and the gradient shearing include three stages: The first stage: stirring at 40°C to 50°C and 500 r / min to 1000 r / min for 10 min to 15 min; The second stage: stirring at 60°C to 70°C and 2000 r / min to 3000 r / min for 20 min to 30 min; The third stage: stirring at 80°C to 90°C, 5000 r / min to 6000 r / min and 0.05 MPa to 0.15 MPa negative pressure for 30 min to 40 min.

[0010] Preferably, in the step 3, the temperature of the polymerization reaction is 65°C to 85°C, the time is 3 h to 5 h, and the oxygen content is controlled to be below 100 ppm during the reaction.

[0011] Preferably, in the step 3, the termination condition of the polymerization reaction is that the viscosity of the plasticizer crude product reaches 2000 mPa·s to 3000 mPa·s.

[0012] Preferably, in the step 4, the filtration adopts a 200-mesh filter screen; the temperature of the devolatilization treatment is 75°C to 90°C, the vacuum degree is 0.03 MPa to 0.08 MPa, and the time is 1 h to 1.5 h.

[0013] The application also provides an application of the plasticizer for paste resins, and the plasticizer obtained by the preparation method of the plasticizer for paste resins is further used for preparing the formed paste resins and applied in the medical industry, the electronic and electrical industry, the automobile manufacturing industry, the building and building material industry, the energy and environmental protection industry and the food and drug packaging industry.

[0014] After the above technical scheme is adopted, the application has the following beneficial effects: 1. By means of the ultrasonic treatment combined with the directional hydrolysis of the silane coupling agent, the amino active sites are introduced on the surface of the carbon nanotubes, and the three-stage gradient temperature rising and shearing process is adopted, so that the soft agglomeration of the nanometer particles is effectively broken, the dispersed particle size is controlled, and the compatibility of the nanomaterial and the matrix is significantly improved.

[0015] 2. The epoxy group of the functional monomer glycidyl methacrylate reacts with the amino group of the nanomaterial, and a stable three-dimensional network structure is formed through radical polymerization under nitrogen protection, thereby enhancing the heat resistance and mechanical properties of the material.

[0016] 3. The obtained plasticizer is used to prepare a paste resin, and the thermal stability and volume resistivity of the paste resin are obviously improved compared with traditional processes; the mechanical properties and chemical resistance are excellent, and the paste resin can meet the needs of high-end fields such as medical catheters and high-temperature cables.

[0017] 4. The environmental plasticizer is combined with the vacuum devolatilization process to reduce the residue of small molecules, i.e., monomers, so that the paste resin product can be applied to the fields of medical and food packaging. DETAILED DESCRIPTION

[0018] The features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. The present application can be implemented without some of these specific details by those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0019] The embodiment of the present application provides a plasticizer preparation method for a paste resin, which specifically comprises the following steps: Step 1: raw material processing The carbon nanotubes are soaked in an ethanol solution containing a silane coupling agent, ultrasonic treatment is performed for 30 min to 40 min, and then the carbon nanotubes are transferred to a centrifugal dryer in a negative pressure environment for centrifugal drying for 2 h to 3 h to obtain a pretreated nanomaterial.

[0020] In the above steps, the concentration of the ethanol solution is 50% to 60% by mass, and the ultrasonic treatment frequency is 40 kHz to 45 kHz.

[0021] The negative pressure condition of the centrifugal drier is a vacuum degree of 0.05 MPa to 0.1 MPa, and the temperature condition is 55°C to 75°C, and the rotation speed of the centrifugal drier is 2000 r / min to 4000 r / min.

[0022] The silane coupling agent is a silane coupling agent containing an amino group, such as 3-aminopropyl triethoxysilane, which facilitates the introduction of an amino group onto the surface of the nanomaterial.

[0023] In the above process, the carbon nanotubes are immersed in an ethanol solution containing a silane coupling agent, and the oriented hydrolysis reaction of the silane coupling agent can introduce amino groups on the surface of the nanomaterial, thereby providing active sites for subsequent in-situ polymerization; centrifugal drying is used to separate the nanomaterial and the solvent ethanol, avoiding the interference of impurities such as residual solvents on the surface of the nanomaterial on subsequent reactions.

[0024] Step 2: Pre-dispersion treatment According to mass fraction, 80-95 parts of an environmentally friendly plasticizer, 1-5 parts of pretreated nanomaterial, and 3-8 parts of a functional monomer containing an epoxy group are added to a high-speed dispersion kettle, and a three-stage gradient temperature and gradient shear are used for pre-dispersion treatment to obtain a raw material mixture.

[0025] The environmentally friendly plasticizer is dioctyl terephthalate or tris octyl trimellitate, or a mixture of the two in any proportion. Dioctyl terephthalate, as a substitute for traditional plasticizer dioctyl phthalate, has obvious advantages in volume resistivity, cold resistance, low-temperature volatility, and can reduce the impact on human health and the environment. Tris octyl trimellitate has good heat processing performance and compatibility with various resins, which can impart long-term stability to the product.

[0026] The functional monomer containing an epoxy group is glycidyl methacrylate, which contains both active epoxy groups and acrylic groups in its molecular structure. This dual property allows it to participate in both free radical polymerization and ionic polymerization, and cross-linking through the epoxy group. Therefore, adding it as a functional monomer to the plasticizer can significantly improve the material's heat resistance, electrical insulation, and weather resistance, etc. In addition, glycidyl methacrylate is compatible with a variety of resins, providing good processing performance and physical properties.

[0027] The specific parameters of the three-stage gradient temperature and shear are as follows: In the first stage, the temperature is 40-50°C, the stirring speed is 500-1000 r / min, and the stirring time is 10-15 min. The purpose of this process is to achieve the initial mixing of various materials and the initial wetting of the nanomaterial. In the second stage, the temperature is 60-70°C, the stirring speed is 2000-3000 r / min, and the stirring time is 20-30 min. The purpose of this process is to achieve the initial homogenization of the nanomaterial through stirring, breaking the soft agglomeration of the nanoparticles. The third stage is stirring at 80-90°C and 5000-6000r / min for 30-40min, and a negative pressure of 0.05-0.15MPa is applied in the dispersion kettle at the same time, so as to further mix the components and remove the bubbles to form a uniform pre-polymer slurry.

[0028] In the above steps, the gradient temperature and gradient shear work together to achieve sufficient mixing of the components, break the soft agglomeration of nanoparticles, and effectively remove the bubbles in the third stage with the vacuum effect, avoiding the negative effect of bubbles on the subsequent polymerization reaction and affecting the product quality.

[0029] Step 3: Polymerization reaction The raw material mixture obtained in step 2 is transferred to a reaction kettle, heated to 65-85°C, and an initiator is added. After stirring and purging with nitrogen for 3-5h, a crude plasticizer is obtained.

[0030] The initiator is azobisisobutyronitrile, which can generate free radicals smoothly when heated to decompose, so that the molecular weight and structure of the polymer can be accurately adjusted, thereby effectively improving the heat resistance, electrical insulation and weather resistance of the plasticizer.

[0031] The amount of initiator added is 3-6% of the mass of the pretreated nanomaterial added in step 2.

[0032] In the above reaction process, nitrogen is purged into the reaction kettle, and the gas in the reaction kettle is discharged to control the oxygen content in the reaction kettle. Generally, the oxygen content in the reaction kettle is controlled to be less than 100ppm during the reaction process to avoid too high oxygen content to hinder the polymerization of free radicals.

[0033] In addition, in the above reaction process, the progress of the polymerization reaction is detected by an online viscometer. When the viscosity of the crude plasticizer in the reaction kettle reaches 2000-3000mPa·s, the reaction is terminated.

[0034] In the above step, the epoxy group of the functional monomer glycidyl methacrylate reacts with the amino group of the pretreated nanomaterial to form a covalent bond, realizing chemical anchoring of the nanomaterial in the plasticizer; at the same time, the acrylate group of glycidyl methacrylate self-polymerizes and grafts with the nanomaterial to form a three-dimensional network structure.

[0035] The synergistic effect of chemical anchoring and network enhancement can realize precise customization of material performance and meet the stringent requirements of medical catheters, high-temperature cables and other high-end application scenarios for plasticizing systems.

[0036] Step 4: Post-treatment The plasticizer crude product obtained in step 3 is filtered using a 200-mesh filter screen and transferred to a reaction kettle for devolatilization treatment, and the obtained solid product is the plasticizer finished product.

[0037] In the above process, since the nano-materials are prone to soft aggregation, the aggregated nano-materials cannot participate in the above polymerization process, and the aggregated nano-materials that have undergone soft aggregation are coated by the polymerization product after the above polymerization process, thereby forming coated particles. Therefore, the coated particles formed by the aggregation of the nano-materials in the plasticizer need to be removed by filtration.

[0038] In the above process, since the thermal decomposition products of azobisisobutyronitrile may include toxic products such as tetramethyl succinonitrile, in order to ensure production safety, a part of the terminator, such as hydroquinone, can be added to decompose the residual azobisisobutyronitrile before the devolatilization treatment in the post-treatment according to the actual production situation and the residual amount of azobisisobutyronitrile.

[0039] In the above process, the heating temperature in the devolatilization treatment is 75-90°C, the vacuum degree is 0.03-0.08 MPa, and the devolatilization treatment time is 1-1.5 h. The devolatilization treatment can remove the monomers and small molecular byproducts remaining in the plasticizer, thereby improving the purity of the plasticizer finished product.

[0040] The plasticizer prepared by the above method can effectively improve the comprehensive performance of the paste resin when used in the preparation process of the paste resin, and is particularly suitable for high-end fields with strict requirements on heat resistance, insulation, and mechanical strength.

[0041] Specifically, the paste resin prepared by using the above plasticizer can be applied to the medical industry due to its chemical resistance, environmental friendliness, and flexibility, for example, as a raw material for medical catheters, infusion bags, surgical instrument sheaths, or wearable medical devices.

[0042] The paste resin prepared by using the above plasticizer can also be applied to the electronic and electrical industries due to its high-temperature resistance and high insulation properties, for example, as a high-temperature cable insulation layer, a flexible circuit board substrate, a transformer packaging material, or a new energy vehicle charging pile cable.

[0043] The paste resin prepared by using the above plasticizer can also be applied to the automotive manufacturing industry due to its weather resistance and environmental friendliness, for example, to make aging-resistant interior parts, sealing strips, battery pack insulation films, and high-pressure wire harness sheaths.

[0044] The paste resin prepared by using the above plasticizer can also be applied to the construction and building materials industry due to its weather resistance and excellent mechanical properties, for example, to produce weather-resistant waterproof rolls, environmentally friendly board coatings, or pipe sealants.

[0045] The paste resin prepared by using the plasticizer can also be widely applied in energy and environmental protection industries, such as used as a lithium ion battery diaphragm, a fuel cell proton exchange membrane, or a solar backboard packaging adhesive, based on its weather resistance and thermal stability and other performances.

[0046] The paste resin prepared by using the plasticizer can also be applied in food and drug packaging industries, such as used as a drug barrier packaging film, a high-temperature resistant cooking bag or a food packaging bag, due to its thermal stability and environmental protection properties.

[0047] In order to facilitate further understanding of the present application, several embodiments and comparative examples of the present application are given as follows: Example 1 Step 1: The carbon nanotubes were soaked in a 55% mass concentration silane coupling agent-containing ethanol solution, treated by ultrasonic waves with a frequency of 40 kHz for 30 min, and then transferred to a centrifugal dryer with a temperature of 60°C, a vacuum degree of 0.05 MPa and a rotating speed of 3000 r / min for centrifugal drying for 2 h to obtain a pretreated nanomaterial.

[0048] Step 2: 40 parts of dioctyl terephthalate, 45 parts of trioctyl trimellitate, 5 parts of the pretreated nanomaterial and 3 parts of glycidyl methacrylate were added into a high-speed dispersion kettle, the temperature of the kettle was first adjusted to 40°C, the rotating speed was adjusted to 500 r / min, and stirring was performed for 10 min, then the temperature of the kettle was adjusted to 60°C, the rotating speed was adjusted to 2000 r / min, and stirring was performed for 20 min, finally the temperature of the kettle was adjusted to 80°C, the rotating speed was adjusted to 5000 r / min, the pressure in the kettle was adjusted to 0.1 MPa, and stirring was performed for 30 min to obtain a raw material mixture.

[0049] Step 3: The raw material mixture was transferred to a reaction kettle, heated to 70°C, 0.25 parts by mass of azobisisobutyronitrile was added, fully stirred and reacted for 3 h under nitrogen to obtain a crude plasticizer.

[0050] Step 4: The crude plasticizer was filtered using a 200-mesh filter screen, and then transferred to a reaction kettle with a temperature of 80°C and a vacuum degree of 0.05 MPa for reaction for 1 h to obtain a finished plasticizer.

[0051] Example 2 This example is based on Example 1, and the amount of the pretreated nanomaterial in Step 2 and the amount of azobisisobutyronitrile in Step 3 are adjusted, which are as follows: Step 2: 40 parts of dioctyl terephthalate, 45 parts of trioctyl trimellitate, 3 parts of pretreated nanomaterial, and 3 parts of glycidyl methacrylate were added into a high-speed dispersion kettle. First, the temperature of the kettle was adjusted to 40℃, the rotating speed was adjusted to 500r / min, and stirring was performed for 10 min. Then, the temperature of the kettle was adjusted to 60℃, the rotating speed was adjusted to 2000r / min, and stirring was performed for 20 min. Finally, the temperature of the kettle was adjusted to 80℃, the rotating speed was adjusted to 5000r / min, the pressure in the kettle was adjusted to 0.1MPa, and stirring was performed for 30 min to obtain a raw material mixture.

[0052] Step 3: The raw material mixture was transferred into a reaction kettle, the temperature was raised to 70℃, 0.15 parts by mass of azobisisobutyronitrile was added, and stirring and nitrogen purging were performed for 3h to obtain a crude plasticizer.

[0053] The remaining steps of this example were identical to those of Example 1.

[0054] Example 3 This example was based on Example 1, and the amount of glycidyl methacrylate in Step 2 was adjusted. Specifically: Step 2: 40 parts of dioctyl terephthalate, 45 parts of trioctyl trimellitate, 3 parts of pretreated nanomaterial, and 3 parts of glycidyl methacrylate were added into a high-speed dispersion kettle. First, the temperature of the kettle was adjusted to 40℃, the rotating speed was adjusted to 500r / min, and stirring was performed for 10 min. Then, the temperature of the kettle was adjusted to 60℃, the rotating speed was adjusted to 2000r / min, and stirring was performed for 20 min. Finally, the temperature of the kettle was adjusted to 80℃, the rotating speed was adjusted to 5000r / min, the pressure in the kettle was adjusted to 0.1MPa, and stirring was performed for 30 min to obtain a raw material mixture.

[0055] The remaining steps of this example were identical to those of Example 1.

[0056] Example 4 This example was based on Example 1, and the parameters of the reaction kettle in Step 4 were adjusted. Specifically: Step 4: The crude plasticizer was filtered using a 200-mesh filter and was transferred into a reaction kettle with a temperature of 90℃ and a vacuum degree of 0.05MPa for 1.5h to obtain a finished plasticizer.

[0057] The remaining steps of this example were identical to those of Example 1.

[0058] Comparative Example 1 This comparative example was based on Example 1, and the treatment method of the carbon nanotubes in Step 1 was adjusted by deleting the ultrasonic treatment step. Specifically: Step 1: The carbon nanotubes were soaked in a 55% mass concentration silane coupling agent ethanol solution and transferred to a centrifugal dryer with a temperature of 60°C, a vacuum degree of 0.05 MPa, and a rotation speed of 3000 r / min for centrifugal drying for 2 h to obtain a pretreated nanomaterial.

[0059] The specific steps of the present comparative example were exactly the same as those of Example 1.

[0060] Comparative Example 2 The present comparative example was based on Example 1, and the parameters of the dispersion kettle in Step 2 were adjusted, specifically as follows: Step 2: 40 parts of dioctyl terephthalate, 45 parts of trioctyl trimellitate, 5 parts of the pretreated nanomaterial, and 3 parts of glycidyl methacrylate were added to a high-speed dispersion kettle, the temperature of the dispersion kettle was first adjusted to 50°C, the rotation speed was adjusted to 2500 r / min, and stirring was performed for 30 min, then the temperature of the dispersion kettle was adjusted to 80°C, the rotation speed was adjusted to 5000 r / min, the kettle internal pressure was adjusted to 0.1 MPa, and stirring was performed for 30 min to obtain a raw material mixture.

[0061] The remaining steps of the present comparative example were exactly the same as those of Example 1.

[0062] Comparative Example 3 The present comparative example was based on Example 1, and the reaction conditions in Step 3 were adjusted, and nitrogen was not introduced, specifically as follows: Step 3: The raw material mixture was transferred to a reaction kettle, the temperature was raised to 70°C, 0.25 parts by mass of azobisisobutyronitrile was added, and full stirring was performed for 3 h to obtain a crude plasticizer.

[0063] The dispersion particle size of the nanomaterial in the plasticizer finished product obtained in the above examples and comparative examples was detected by a laser particle size instrument, the amount of epoxy groups was detected by an infrared spectrum analyzer, and the conversion rate of epoxy groups was calculated according to the amount of epoxy groups.

[0064] The nanomaterial dispersion particle size and the conversion rate of epoxy groups in the above examples and comparative examples were recorded and counted, and the data are shown in the following table.

[0065]

[0066] According to the above data, it can be seen that: The carbon nanotubes in Example 1 and Example 4 are dispersed by ultrasonic treatment and gradient shear, effectively breaking the soft agglomeration and achieving good dispersion uniformity. Nitrogen is used to control the oxygen content during the polymerization process, avoiding the inhibition of free radical polymerization. The three-stage temperature shear promotes the full reaction of the functional monomer and the nanomaterial, so the nanomaterial dispersion particle size of Example 1 and Example 4 is ideal, and the epoxy group conversion rate in Example 4 is slightly higher than that in Example 1, because the optimization of the devolatilization condition reduces the by-products.

[0067] In Example 2, the amount of pretreated nanomaterial is reduced, which may cause uneven distribution of shear force in the dispersion system, slightly affecting the dispersion effect; in addition, the amount of initiator is reduced, and the amount of free radicals generated is reduced, resulting in some epoxy groups not participating in the reaction.

[0068] In Example 3, the amount of functional monomer glycidyl methacrylate is increased, providing additional active groups, enhancing the chemical anchoring of nanomaterials, inhibiting agglomeration, and increasing the proportion of functional monomers, increasing the reaction sites of epoxy groups and amino groups, and the reaction is more complete.

[0069] In Comparative Example 1, the lack of ultrasonic treatment leads to insufficient disintegration of carbon nanotubes, forming large-size agglomerates, and further leading to insufficient active sites on the surface of nanomaterials, limiting the efficiency of ring-opening reaction of epoxy groups and amino groups.

[0070] In Comparative Example 2, the reaction conditions of two-stage gradient temperature shear are used, which directly causes the nanomaterials to be subjected to high shear force at high temperature, resulting in incomplete breaking of soft agglomeration, and uneven dispersion of nanomaterials, leading to some functional monomers unable to effectively contact the nanomaterials, thereby affecting the completion of the reaction.

[0071] In Comparative Example 3, the dispersion process is not affected by oxygen, but the oxygen content is high during the polymerization stage, leading to the quenching of free radicals, and the inhibition of free radical polymerization by oxygen, which hinders the grafting reaction of acrylate groups, and the three-dimensional network structure is not fully formed.

[0072] The plasticizers prepared by the above examples and comparative examples are used to prepare paste resin samples, and the paste resin preparation ratio is as follows:

[0073] The plasticizers in different examples and comparative examples are used to prepare paste resin samples, and the viscosity, apparent density, particle size distribution, volatile content, thermal stability, weather resistance, chemical resistance, tensile strength, elongation at break and hardness of each sample are detected, and the data statistics are as follows:

[0074] According to the above data, it can be seen that: Due to the three-stage gradient shear and moderate amount of nanomaterials used in Example 1, the dispersion of nanomaterials is uniform, ensuring a high conversion rate of epoxy groups, and the paste resin sample prepared therefrom has moderate viscosity, good tensile strength and chemical resistance, and meets the thermal stability requirements. In addition, the uniformity of the nanomaterials ensures the stability of the insulating network, and the insulating performance is relatively good.

[0075] In Example 2, the amount of nanomaterials is reduced, the dispersion effect is slightly reduced, and the reaction of epoxy groups is incomplete, resulting in a decrease in the mechanical properties of the paste resin sample, and a lower tensile strength and elongation at break.

[0076] In Example 3, the amount of functional monomer glycidyl methacrylate is increased, the conversion rate of epoxy groups is increased, the chemical anchoring is enhanced, and a uniform and dispersed insulating network is formed. Therefore, the performance of the paste resin sample prepared therefrom is the best, the particle size is the smallest, and the tensile strength, weather resistance, chemical resistance, and volume resistivity are all the best.

[0077] In Example 4, the devolatilization temperature is increased to 90°C, resulting in the lowest volatile content, which slightly improves the thermal stability of the paste resin prepared therefrom. In addition, increasing the devolatilization temperature reduces impurities in the composition, and the insulating performance is slightly improved compared to Example 1.

[0078] In Comparative Example 1, the use of ultrasonic treatment leads to severe agglomeration of nanomaterials, and the conversion rate of epoxy groups is low, resulting in a comprehensive decline in the performance of the paste resin prepared therefrom, with high viscosity, low chemical resistance, thermal stability, and insulating performance.

[0079] In Comparative Example 2, the nanomaterials are treated using a two-stage gradient temperature and shear method, which slightly affects the breaking of soft agglomerates, resulting in a higher volatile content in the paste resin prepared therefrom, and a weather resistance below the medium level.

[0080] In Comparative Example 3, nitrogen is not passed during the plasticizer polymerization stage, resulting in oxygen inhibition of free radical polymerization, and a three-dimensional network is not formed, with an epoxy group conversion rate of only 68.9%. This further affects the performance of the paste resin sample prepared therefrom, with the highest viscosity, significantly reduced tensile strength and weather resistance, and a significant decrease in insulating performance due to the absence of a three-dimensional network.

[0081] In accordance with the present application as described above, the foregoing examples have not been described in detail with respect to all of the specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments. Thus, it should be understood that the description is in all aspects to be considered only as a representative example of the principles of the application and not in a limiting sense. It is intended that any modification, change, substitution, or equivalent be included within the spirit and scope of this application.

Claims

1. A method for preparing a plasticizer for paste resins, characterized by, It comprises the following steps: Step 1: carbon nanotubes are soaked in an ethanol solution containing a silane coupling agent, ultrasonic treatment and centrifugal drying are performed, and a pretreated nanomaterial is obtained; Step 2: an environmentally friendly plasticizer, a pretreated nanomaterial and an epoxy group-containing functional monomer are added to a dispersion kettle, and pre-dispersion treatment is performed through gradient heating and gradient shearing, and a raw material mixture is obtained; Step 3: the raw material mixture is transferred to a reaction kettle, an initiator is added, and a polymerization reaction is performed under nitrogen protection, and a plasticizer crude product is obtained; Step 4: the plasticizer crude product is filtered and devolatilized to obtain a plasticizer finished product. The environmentally friendly plasticizer is dioctyl terephthalate or tris octyl trimellitate, or a mixture of the two in any proportion, and the epoxy group-containing functional monomer is glycidyl methacrylate.

2. The method for preparing a plasticizer for a paste resin according to claim 1, characterized by, The initiator is azobisisobutyronitrile, and the addition amount of the initiator is 3% to 6% of the mass of the pretreated nanomaterial.

3. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 1, the mass concentration of the ethanol solution is 50% to 60%, the frequency of the ultrasonic treatment is 40 kHz to 45 kHz, and the time is 30 min to 40 min; the vacuum degree of the centrifugal drying is 0.05 MPa to 0.1 MPa, the temperature is 55°C to 75°C, and the rotation speed is 2000 r / min to 4000 r / min.

4. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 2, the mass ratio of the environmentally friendly plasticizer, the pretreated nanomaterial and the epoxy group-containing functional monomer is 80 to 95: 1 to 5: 3 to 8.

5. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 2, the gradient heating and gradient shearing include three stages: First stage: stirring at 40°C to 50°C and 500 r / min to 1000 r / min for 10 min to 15 min; Second stage: stirring at 60°C to 70°C and 2000 r / min to 3000 r / min for 20 min to 30 min; Third stage: stirring at 80°C to 90°C, 5000 r / min to 6000 r / min and 0.05 MPa to 0.15 MPa negative pressure for 30 min to 40 min.

6. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 3, the temperature of the polymerization reaction is 65°C to 85°C, the time is 3 h to 5 h, and the oxygen content during the reaction is controlled to be below 100 ppm.

7. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 3, the termination condition of the polymerization reaction is that the viscosity of the plasticizer crude product reaches 2000 mPa·s to 3000 mPa·s.

8. The method for preparing a plasticizer for a paste resin according to Claim 1, characterized by, In step 4, a 200-mesh filter screen is used for filtration; the temperature of the devolatilization treatment is 75°C to 90°C, the vacuum degree is 0.03 MPa to 0.08 MPa, and the time is 1 h to 1.5 h.

9. Use of a plasticizer for a paste resin, characterized by, The plasticizer obtained by the method for preparing a paste resin plasticizer according to any one of claims 1 to 8 is further used to prepare the application of the formed paste resin in the medical industry, the electronic and electrical industry, the automobile manufacturing industry, the building and building material industry, the energy and environmental protection industry, and the food and drug packaging industry.

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