A peroxide crosslinking agent and a production process thereof

Abstract

This invention relates to the field of crosslinking agent preparation technology, specifically to a peroxide crosslinking agent and its production process. The raw materials for preparation consist of α,α'-dihydroxy-1,3-diisopropylbenzene, tert-butyl hydroperoxide, an initiator, a co-crosslinking agent, a regulator, and dichloromethane. The initiator is a compound of acetic acid and perchloric acid mixed in a mass ratio of 1:0.05-0.2. The co-crosslinking agent is a compound of triallyl isocyanurate and vinyltrimethoxysilane in a mass ratio of 1:0.5-1.5, or a compound of triallyl isocyanurate, vinyltrimethoxysilane, and N,N'-m-phenylenebismaleimide in a mass ratio of 1:0.6-1.0:0.4-0.6. The regulator is dibutyltin dilaurate. This invention employs a specific compound initiator, which can stably control the oxidation reaction process, avoid runaway reaction, improve the conversion rate of intermediate products, reduce the generation of by-products from the source, reduce the content of volatile substances in the system, shorten the post-treatment degassing cycle, and reduce production energy consumption.

Description

Technical Field

[0001] This invention relates to the field of crosslinking agent preparation technology, specifically to a peroxide crosslinking agent and its production process. Background Technology

[0002] Peroxide crosslinking agents are core additives for crosslinking modification of polymer materials. They are widely used in rubber, plastics, photovoltaic encapsulation materials and sealing products, and their performance directly determines the heat resistance, mechanical strength and service life of polymer materials.

[0003] Currently, most peroxide crosslinking agents used in the industry are based on a single peroxide as the core component. These agents suffer from drawbacks such as a simple crosslinking structure and limited performance control, making it difficult to simultaneously meet the material's dual requirements for heat resistance and elasticity. Existing production processes mostly employ isothermal reaction modes, which are prone to localized overheating or uneven reaction, resulting in high levels of byproducts. Subsequent degassing and purification processes are time-consuming and energy-intensive, significantly increasing production costs.

[0004] Existing technologies often use single-component initiators, which cannot precisely control the reaction initiation rate, easily leading to uncontrolled reaction processes and affecting product purity and batch stability. Crosslinking agents are mostly single-variety blends, making it difficult to synergistically improve crosslinking density and crosslink bond flexibility, resulting in crosslinked products being prone to deformation and mechanical property degradation at high temperatures.

[0005] Meanwhile, the raw material ratio and reaction condition design of traditional processes are relatively crude. Problems such as insufficient dissolution of raw materials and residual moisture will further aggravate side reactions and reduce the product qualification rate.

[0006] As the requirements for material performance continue to increase in the high-end manufacturing sector, existing crosslinking agents are no longer suitable for high-temperature and high-toughness applications such as photovoltaics and automotive seals. The industry urgently needs a new type of peroxide crosslinking agent with excellent crosslinking performance, few by-products, stable production, and the ability to balance heat resistance and elasticity, as well as a supporting production process, to solve the above problems. Summary of the Invention

[0007] The primary objective of this invention is to provide a peroxide crosslinking agent and its manufacturing process.

[0008] A further objective of this invention is to provide a peroxide crosslinking agent, the raw materials of which consist of α,α'-dihydroxy-1,3-diisopropylbenzene, tert-butyl hydroperoxide, an initiator, a co-crosslinking agent, a regulator, and dichloromethane; the initiator is a compound of acetic acid and perchloric acid mixed in a mass ratio of 1:0.05-0.2; the co-crosslinking agent is a compound of triallyl isocyanurate and vinyltrimethoxysilane in a mass ratio of 1:0.5-1.5, or a compound of triallyl isocyanurate, vinyltrimethoxysilane, and N,N'-m-phenylenebismaleimide in a mass ratio of 1:0.6-1.0:0.4-0.6; the regulator is dibutyltin dilaurate.

[0009] Preferably, the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butylhydroperoxide is 1:1.0-1:2.0.

[0010] Preferably, the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the initiator is 1:0.1-1:0.8; the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the co-crosslinking agent is 1:0.2-1:1.5; and the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the regulator is 1:0.05-1:0.2.

[0011] Preferably, the amount of dichloromethane used is 5 to 8 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene.

[0012] A production process for the peroxide crosslinking agent includes raw material pretreatment, oxidation reaction, ring-closure reaction, and post-treatment steps. The raw material pretreatment involves dissolving α,α'-dihydroxy-1,3-diisopropylbenzene in dichloromethane under stirring to obtain a pretreatment solution; tert-butyl hydroperoxide is purified by vacuum distillation; and the initiator, co-crosslinking agent, and regulator are dried to remove water. The oxidation reaction involves adding the pretreatment solution to a reactor, controlling the initial temperature, adding purified tert-butyl hydroperoxide dropwise, and then adding the initiator and stirring to obtain an intermediate product after gradient heating. The ring-closure reaction involves adding the co-crosslinking agent and regulator to the reactor, and then stirring under gradient heating until the viscosity of the system reaches 150 mPa·s-220 mPa·s at 25°C, rotor No. 2, and 20 r / min, at which point the reaction is stopped, yielding a crude product. The post-treatment involves washing, separating, vacuum distilling, drying, and pulverizing the crude product to obtain the finished product.

[0013] Preferably, the initial temperature of the oxidation reaction is 0°C, the time for adding tert-butyl hydroperoxide is 30 min to 60 min, and after the addition is completed, the temperature is gradually increased to 8°C to 10°C at a rate of 2°C / h, the stirring speed is 300 r / min to 450 r / min, and the reaction time is 24 h to 40 h.

[0014] Preferably, the closed-loop reaction is heated from 15°C to 20°C at a rate of 3°C / h, the stirring speed is 400r / min-550r / min, and the reaction time is 24h-42h.

[0015] Preferably, the stirring and dissolving temperature in the raw material pretreatment is 25℃-30℃, and the drying and dehydration temperature is 80℃-85℃; the purification conditions for tert-butyl hydroperoxide are 0.08MPa and 50℃.

[0016] Preferably, the post-treatment involves washing the crude product with deionized water 3-4 times, with each wash using twice the amount of crude product; the vacuum distillation pressure is 0.07MPa-0.08MPa, and the temperature is 60℃-75℃.

[0017] Preferably, the drying conditions for the post-treatment are 100℃-110℃, 0.1MPa, and drying time is 4h-7h; the particle size of the finished product after pulverization is 80 mesh-120 mesh.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a specific compound initiator, which can stably control the oxidation reaction process, avoid reaction runaway, improve the conversion rate of intermediate products, reduce the generation of by-products from the source, reduce the content of volatile substances in the system, shorten the post-treatment degassing cycle, and reduce production energy consumption.

[0019] 2. The compound crosslinking agent system of the present invention can synergistically optimize the crosslinking structure, simultaneously improve the crosslinking density and crosslinking bond flexibility of the material, effectively balance the heat resistance and elasticity of the crosslinked product, and solve the technical problem that traditional products cannot achieve both heat resistance and elasticity.

[0020] 3. The stepwise reaction process with gradient heating of the present invention can make the oxidation and ring-closing reactions proceed uniformly, improve the purity and batch stability of the product, and ensure the stable and controllable performance of the crosslinking agent.

[0021] 4. The optimized raw material pretreatment and posttreatment process of this invention can fully dissolve raw materials, remove impurities and moisture, further improve reaction stability and product purity, while simplifying operation steps and adapting to continuous industrial production.

[0022] 5. Compared with traditional single peroxide crosslinking agents, the product prepared by this invention has better thermal stability, mechanical properties and processing performance, and can be widely adapted to high-end application scenarios such as photovoltaic packaging, cable materials, and automotive seals. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: The molar ratio of raw materials is 1:1.0:0.1:0.2:0.05 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinker to regulator. The initiator is a mixture of acetic acid and perchloric acid; their combined use allows for precise control of the oxidation reaction initiation rate, preventing the reaction from being too slow or too violent. The co-crosslinker is a compound of triallyl isocyanurate and vinyltrimethoxysilane in a 1:1 mass ratio, which initially increases the crosslinking density and improves heat resistance. The regulator is dibutyltin dilaurate, which effectively controls the reaction rate, improves reaction stability, and enhances product purity. The solvent is dichloromethane, used in an amount five times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene, ensuring complete dissolution of all raw materials and guaranteeing a uniform reaction.

[0025] Production process steps: Raw material pretreatment: α,α'-dihydroxy-1,3-diisopropylbenzene was added to dichloromethane and stirred at 25°C and 300 rpm for 30 min until completely dissolved to obtain a pretreated solution. Tert-butyl hydroperoxide was purified by vacuum distillation at 0.08 MPa and 50°C to remove moisture and impurities, avoiding the influence of moisture on reaction stability and product purity. The initiator, crosslinking agent, and regulator were dried at 80°C for 2 h to remove moisture, further ensuring reaction stability.

[0026] Step 1 Oxidation Reaction: The pretreated solution was added to the reactor, with the initial temperature controlled at 0℃ and the stirring speed maintained at 300 r / min. Purified tert-butyl hydrogen peroxide was slowly added dropwise over 60 min. Slow addition avoided vigorous localized reactions. After the addition was complete, the temperature was gradually increased to 8℃ at a rate of 2℃ / h. An initiator was added, and the reaction was continued with stirring for 24 h to obtain the intermediate product. Low-temperature gradient heating can improve the conversion rate of the intermediate product and reduce the formation of byproducts.

[0027] The second step is the closed-loop reaction: add the crosslinking agent and regulator to the reactor, gradually increase the temperature from 15℃ to 20℃ at a rate of 3℃ / h, adjust the stirring speed to 400r / min, and continue stirring for 24h. Monitor the viscosity of the system in real time. When the viscosity reaches 150mPa·s, stop the reaction to obtain the crude product. The medium-temperature gradient heating can promote the uniformity of the closed-loop reaction and improve the purity of the crosslinking agent.

[0028] Post-processing: The crude product was washed three times with deionized water, each time using twice the amount of crude water. The aqueous phase was removed by separation to remove water-soluble impurities. The organic phase was then distilled under reduced pressure at 0.08 MPa and 60 °C to remove dichloromethane and low-boiling-point byproducts. The distilled product was dried at 100 °C and 0.1 MPa for 4 hours and then pulverized to a particle size of 80 mesh to obtain the peroxide crosslinking agent product. This product meets the basic crosslinking requirements and lays the foundation for the optimization and expansion of subsequent embodiments.

[0029] Example 2: Based on Example 1, the raw material ratio was optimized, the amount of tert-butyl hydrogen peroxide and crosslinking agent was increased, and the amount of initiator was adjusted to specifically improve crosslinking efficiency and reduce by-product generation.

[0030] The molar ratio of raw materials is 1:1.5:0.3:0.8:0.1 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinker to regulator. The types of initiator, co-crosslinker, regulator, and solvent are the same as in Example 1. The amount of solvent used is 6 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene. Increasing the amount of solvent can further improve the solubility of the raw materials and ensure the uniformity of the reaction.

[0031] Production process steps: Raw material pretreatment: Same as in Example 1, except that the stirring speed was adjusted to 350 r / min to ensure that α,α'-dihydroxy-1,3-diisopropylbenzene was completely dissolved, improve the homogeneity of the pretreatment solution, and lay a good foundation for subsequent reactions.

[0032] The first step of the oxidation reaction: The pretreated solution was added to the reactor, with the initial temperature controlled at 0℃ and the stirring speed maintained at 350 r / min. Purified tert-butyl hydrogen peroxide was slowly added dropwise over 45 min, shortening the addition time while ensuring a stable reaction. After the addition was complete, the temperature was gradually increased to 8℃ at a rate of 2℃ / h. The initiator was added, and the reaction was continued with stirring for 30 h to obtain the intermediate product. Extending the reaction time and optimizing the stirring speed can promote the complete oxidation reaction, improve the conversion rate of the intermediate product, reduce unreacted raw material residue, and further reduce by-products.

[0033] The second step, the ring-closure reaction, involves adding a crosslinking agent and a regulator to the reactor. The temperature is gradually increased from 15°C to 20°C at a rate of 3°C / h, while the stirring speed is adjusted to 450 r / min. The reaction is continued for 30 hours, with the viscosity of the system monitored in real time. When the viscosity reaches 180 mPa·s, the reaction is stopped, yielding the crude product. Increasing the amount of crosslinking agent promotes a more complete ring-closure reaction, increases the crosslinking density, further reduces byproducts, and improves crosslinking efficiency.

[0034] Post-processing: Same as in Example 1, except that the vacuum distillation temperature was adjusted to 65°C and the drying time was adjusted to 5 hours to ensure complete removal of solvent and byproducts, improve the purity of the finished product, and significantly improve the performance of the prepared crosslinking agent compared to Example 1, making it suitable for more basic crosslinking scenarios.

[0035] Example 3: Based on Example 2, the reaction temperature gradient and stirring speed were further optimized, and the ratio of regulators was adjusted to specifically improve the heat resistance of the crosslinking agent.

[0036] The molar ratio of raw materials is 1:1.8:0.5:1.2:0.15 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinker to regulator. The types of initiator, co-crosslinker, regulator, and solvent are the same as in Example 1. The amount of solvent used is 7 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene, which is suitable for dissolving higher amounts of raw materials.

[0037] Production process steps: Raw material pretreatment: α,α'-dihydroxy-1,3-diisopropylbenzene was added to dichloromethane and stirred at 30°C and 400 rpm for 25 min until completely dissolved to obtain a pretreated solution. The purification conditions for tert-butyl hydroperoxide were the same as in Example 1. The initiator, co-crosslinking agent, and regulator were dried at 85°C for 1.5 h to remove moisture, further improving reaction stability and avoiding abnormal reactions at high temperatures.

[0038] Step 1 Oxidation Reaction: The pretreated solution was added to the reactor, with the initial temperature controlled at 0℃ and the stirring speed at 350 rpm. Tert-butyl hydrogen peroxide was added dropwise over 40 minutes. After the addition was complete, the temperature was gradually increased to 8℃, with an increase of 2℃ per hour. The initiator was added, and the reaction was continued with stirring for 36 hours to obtain the intermediate product. This gradient heating method effectively avoids local overheating, reduces the formation of by-products, and improves the purity of the intermediate product, laying the foundation for the subsequent ring-closure reaction and ensuring improved heat resistance.

[0039] The second step, the ring-closure reaction, involves adding a crosslinking agent and a regulator to the reactor. The temperature is gradually increased from 15°C to 20°C at a rate of 3°C per hour, while the stirring speed is adjusted to 500 rpm. The reaction is continued for 36 hours with constant stirring, and the viscosity of the system is monitored in real time. When the viscosity reaches 200 mPa·s, the reaction is stopped, yielding the crude product. Gradual heating promotes a uniform ring-closure reaction and improves the heat resistance of the crosslinking agent, meeting the requirements for use in high-temperature environments.

[0040] Post-processing: The crude product was washed four times with deionized water, each time using twice the amount of crude water. The aqueous phase was removed by separation to thoroughly remove impurities. The organic phase was then distilled under reduced pressure at 0.07 MPa and 70°C to remove solvent and low-boiling-point byproducts. The distilled product was dried at 110°C and 0.1 MPa for 6 hours and pulverized to a particle size of 100 mesh to obtain the peroxide crosslinking agent. This product exhibits significantly improved heat resistance compared to Example 2 and is suitable for applications in high-temperature environments such as photovoltaic encapsulation and cable materials.

[0041] Example 4: Based on Example 3, the compounding ratio of the co-crosslinking agent was adjusted, and N,N'-m-phenylenebismaleimide was introduced as a co-crosslinking agent component. This balanced the heat resistance and elasticity of the crosslinking agent, addressing the core pain point of the imbalance between heat resistance and elasticity in existing peroxide crosslinking agents, while also verifying the feasibility of the upper limit of the raw material ratio. The molar ratio of the raw materials was 1:2.0:0.8:1.5:0.2 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinking agent to regulator. The co-crosslinking agent was adjusted to a compound of triallyl isocyanurate, vinyltrimethoxysilane, and N,N'-m-phenylenebismaleimide, with a mass ratio of 1:0.8:0.5. This compound system can synergistically improve the crosslinking density and crosslinking bond flexibility, achieving a balance between heat resistance and elasticity. The types of initiator, regulator, and solvent are the same as in Example 1. The amount of solvent used is 8 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene, which is suitable for the dissolution requirements of the highest raw material usage.

[0042] Production process steps: Raw material pretreatment: Same as in Example 3, except that the stirring speed is adjusted to 450 r / min, the dissolution time is shortened to 20 min, the production efficiency is improved, the production energy consumption is reduced, and the raw materials are fully dissolved.

[0043] The first step of the oxidation reaction: The gradient heating method remains unchanged. Starting at 0°C, tert-butyl hydroperoxide is added dropwise over 35 minutes. The temperature is gradually increased to 10°C, with an increase of 2°C per hour. The initiator is added, and the reaction is continued with stirring for 40 hours to obtain the intermediate product. Extending the reaction time ensures complete oxidation, improves the conversion rate of the intermediate product, provides high-quality raw materials for the subsequent ring-closure reaction, and guarantees the performance of the final product.

[0044] The second step, a closed-loop reaction, continues with the same gradient heating method, gradually increasing the temperature from 15℃ to 20℃. The stirring speed is adjusted to 550 r / min. The adjusted crosslinking aid and regulator are added, and the reaction is continued for 42 hours. The viscosity of the system is monitored in real time. When the viscosity reaches 220 mPa·s, the reaction is stopped, yielding the crude product. The novel crosslinking aid compound system works synergistically to improve both crosslinking density and heat resistance, while also increasing the flexibility of the crosslinking bonds, achieving a perfect balance between heat resistance and elasticity, thus addressing the core pain points of existing technologies.

[0045] Post-processing: Same as in Example 3, except that the vacuum distillation temperature was adjusted to 75°C, the drying time was adjusted to 7 hours, and the powder was pulverized to a particle size of 120 mesh to obtain the peroxide crosslinking agent product. This product has both excellent heat resistance and elasticity, and can be used in scenarios with high requirements for both heat resistance and elasticity, such as automotive seals and high-end building seals.

[0046] Example 5: Based on Example 4, the raw material pretreatment and posttreatment steps were optimized to shorten the reaction time, simplify the process flow, reduce energy consumption, and improve production efficiency. At the same time, intermediate ratio parameters were selected to verify the feasibility of the intermediate ratio, so as to achieve a balance between performance and production efficiency.

[0047] The molar ratio of raw materials is 1:1.2:0.4:1.0:0.12 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinker to regulator. The types of co-crosslinker, initiator, regulator, and solvent are the same as in Example 4. The amount of solvent used is 6.5 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene, balancing dissolution effect and production cost.

[0048] Production process steps: Raw material pretreatment: α,α'-dihydroxy-1,3-diisopropylbenzene and the crosslinking agent were simultaneously added to dichloromethane and stirred at 30°C and 450 rpm for 20 minutes until completely dissolved to obtain a pretreated solution. The purification conditions for tert-butyl hydroperoxide were the same as in Example 1. The initiator and regulator were dried at 80°C for 2 hours to remove moisture. Adding the crosslinking agent to the pretreated solution in advance simplifies subsequent addition steps, improves production efficiency, and ensures uniform dispersion of the crosslinking agent.

[0049] Step 1 Oxidation Reaction: The gradient heating method remains unchanged. Starting at 0°C, tert-butyl hydroperoxide is added dropwise over 30 minutes. The temperature is gradually increased to 8°C, with an increase of 2°C per hour. The initiator and regulator are added, and the reaction is continued with stirring for 32 hours to obtain the intermediate product. Adding the regulator in advance promotes the connection between the oxidation and ring-closing reactions, shortens subsequent reaction times, improves production efficiency, and ensures reaction stability.

[0050] The second step, a closed-loop reaction, requires no additional temperature adjustment. The reaction temperature is gradually increased from 8°C to 20°C, with a stirring speed of 500 rpm. The reaction continues for 36 hours, with real-time monitoring of the system viscosity. When the viscosity reaches 200 mPa·s, the reaction is stopped, yielding the crude product. This simplified temperature adjustment process shortens the reaction time, reduces energy consumption, and ensures stable product performance, making it suitable for continuous industrial production.

[0051] Post-processing: The crude product was washed three times with deionized water, each time using twice the amount of crude water, and the aqueous phase was removed by liquid-liquid separation. The organic phase was then distilled under reduced pressure at 0.07 MPa and 70 °C to remove the solvent and low-boiling-point byproducts. The distilled product was dried at 105 °C and 0.1 MPa for 5 h, and then pulverized to a particle size of 100 mesh to obtain the peroxide crosslinking agent product. Simplifying the washing and drying steps can further improve production efficiency and reduce production costs, providing a feasible technical solution for the industrial application of this invention.

[0052] Comparative Example 1 Using dicumyl peroxide, a commonly used crosslinking agent in existing technologies, the production process employs a traditional single-reaction method, simulating a typical scheme of existing technologies, as detailed below: The raw material is dicumyl peroxide, without crosslinking agents or regulators, and the solvent is dichloromethane, with the amount of solvent being 5 times the mass of dicumyl peroxide.

[0053] Production process: Dicumyl peroxide is added to dichloromethane, stirred and dissolved, and then reacted at a constant temperature of 10°C for 48 hours. The product is then directly subjected to vacuum distillation, drying, and pulverization to obtain the crosslinking agent.

[0054] This comparative example is used to compare the performance differences between the composite peroxide system of the present invention and the traditional single peroxide crosslinking agent, highlighting the significant advantages of the present invention in terms of crosslinking efficiency, by-product content, heat resistance, and mechanical properties, and proving the inventiveness of the raw material system of the present invention, which is not a simple replacement of existing single peroxides.

[0055] Comparative Example 2: Based on Example 1, the crosslinking agent was removed, while the proportions of other raw materials and the production process remained the same as in Example 1. This simulated a scenario where the key component of the present invention was missing, and was used to compare the effect of the crosslinking agent on the performance of the crosslinking agent. This highlighted the inventiveness of the composite crosslinking agent system of the present invention and proved that the crosslinking agent is the core key to achieving both heat resistance and elasticity. Without it, the technical effect of the present invention cannot be achieved.

[0056] Comparative Example 3: Based on Example 2, the first oxidation reaction and the second ring-closing reaction were both carried out at a single temperature of 10°C without using a gradient heating process. The remaining raw material ratios and production processes were the same as in Example 2. This simulated a scenario where the key process of the present invention was missing, and was used to compare the effects of the gradient heating process on the performance of the crosslinking agent and the content of by-products. This highlighted the ingenuity of the process design of the present invention and proved that the gradient heating process is the key to reducing by-products and improving performance. A single isothermal reaction cannot achieve the technical effects of the present invention.

[0057] Comparative Example 4: The raw material molar ratio is 1:2.5:0.8:1.5:0.2 for α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide to initiator to co-crosslinking agent to regulator. This ratio exceeds the range of tert-butyl hydroperoxide in this invention. The remaining production process is consistent with Example 4, used to verify the rationality of the raw material ratio range of this invention, highlighting the scientific basis of expanding the ratio range of this invention, proving that exceeding this range will lead to an increase in by-products and a decrease in performance, further corroborating the rationality and inventiveness of the scope of protection of this invention.

[0058] Comparative Example 5: The crosslinking agent is bis-tert-butylperoxyisopropylbenzene, which is commonly used in existing technologies. The production process adopts a traditional two-step reaction method, simulating a typical scheme of high-performance crosslinking agents in existing technologies, as follows: The raw material is bis-tert-butylperoxyisopropylbenzene, the crosslinking agent is single triallyl isocyanurate, the initiator is benzoyl peroxide, the regulator is dibutyltin dilaurate, and the solvent is dichloromethane.

[0059] Production process: Di-tert-butylperoxyisopropylbenzene and crosslinking agent are dissolved in dichloromethane, initiator and regulator are added, and the reaction is carried out at a constant temperature of 15°C for 48 hours. After washing, vacuum distillation, drying and pulverizing, the crosslinking agent product is obtained.

[0060] This comparative example is used to compare the performance differences between the composite peroxide crosslinking agent of the present invention and the existing high-performance BIPB crosslinking agent, highlighting the advantages of the present invention in terms of by-product content, elasticity, and production efficiency, and proving that the present invention is not a simple combination of existing technologies, but a creative technical solution with substantial improvements.

[0061] To enable those skilled in the art to fully implement this invention, the following key technical parameters and test conditions are provided: In the initiator described in this invention, the mass ratio of acetic acid to perchloric acid is 1:0.05-0.2. This ratio can stably control the initiation rate and reaction progress of the oxidation reaction, avoiding runaway or excessively slow reaction. When the co-crosslinking agent is a binary compound, the mass ratio of triallyl isocyanurate to vinyltrimethoxysilane is 1:0.5-1.5. When a ternary compound is used, the mass ratio of triallyl isocyanurate, vinyltrimethoxysilane, and N,N'-m-phenylenebismaleimide is 1:0.6-1. The compound ratio of 0:0.4-0.6 can synergistically improve the crosslinking density and crosslinking bond flexibility, balancing the product's heat resistance and elasticity. The final viscosity of the closed-loop reaction in this invention is tested using an NDJ-1 rotational viscometer under the following conditions: 25℃, rotor No. 2, and rotation speed of 20 r / min. These testing conditions are industry-standard and can ensure the accuracy and comparability of viscosity data. After raw material pretreatment, the moisture content of the system is controlled to be ≤0.05% to avoid side reactions caused by moisture and to ensure reaction stability and product purity.

[0062] Performance testing and results analysis: The peroxide crosslinking agents of Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to comprehensive performance tests. The test items included crosslinking efficiency (i.e., gel content), thermal aging performance (i.e., tensile strength retention rate after accelerated aging at 120°C for 1000 hours), heat distortion temperature, by-product content (i.e., volatile organic compound concentration), mechanical properties (i.e., tensile strength, elongation at break, impact strength), processing performance (i.e., scorch time, crosslinking time, and degassing time).

[0063] The test results are shown in Table 1 below: Table 1:

[0064] Results analysis: Regarding crosslinking efficiency and thermal aging performance, the gel content of Examples 1 to 5 was all above 91%, significantly higher than that of Comparative Examples 1 to 4, and slightly higher than that of Comparative Example 5. This indicates that the composite peroxide system and gradient heating process of the present invention can effectively improve crosslinking efficiency, significantly outperforming existing single peroxide systems and existing technology combinations. The tensile strength retention rate of Examples 1 to 5 was all above 89%, and the heat distortion temperature was all above 82°C. Among them, the heat distortion temperature of Example 4 reached 90°C, significantly higher than that of Comparative Examples 1 to 4, and slightly higher than that of Comparative Example 5. This indicates that the present invention can effectively improve the heat resistance and aging resistance of the crosslinking agent. Furthermore, by gradually optimizing the raw material ratio and process parameters among the examples, the heat resistance and crosslinking efficiency gradually improved, further verifying the rationality of the scope of protection of the present invention.

[0065] Regarding the by-product content and degassing time, the volatile organic compound concentrations in Examples 1 to 5 were all between 5 and 8, significantly lower than those in Comparative Examples 1 to 4, and slightly lower than that in Comparative Example 5. The degassing times were all between 16 and 24, much shorter than those in Comparative Examples 1 to 4. This indicates that the composite peroxide system and optimized gradient heating process of this invention can effectively reduce by-product generation and shorten degassing time, solving the core problems of long degassing time and high energy consumption in existing technologies. Comparative Example 4, due to the excess of tert-butyl hydrogen peroxide, exceeded the protection scope of this invention, leading to an increase in by-product content and a prolonged degassing time, further verifying the scientific validity and rationality of the raw material ratio range of this invention.

[0066] In terms of mechanical properties, the tensile strength of Examples 1 to 5 is all above 32.5, the elongation at break is all above 480, and the impact strength is all above 102.3. Among them, Example 4 has the best mechanical properties, significantly higher than Comparative Examples 1 to 4, and slightly higher than Comparative Example 5. This indicates that the composite co-crosslinking agent system of the present invention can effectively balance the heat resistance and elasticity of the crosslinking agent, solving the core problem of the imbalance between heat resistance and elasticity in existing peroxide crosslinking agents. Example 5 simplifies the process and improves production efficiency while maintaining excellent mechanical properties, achieving a balance between performance and production efficiency, further demonstrating the practicality and inventiveness of the present invention.

[0067] Regarding processing performance, the scorch times of Examples 1 to 5 were all between 14 and 18 seconds, and the crosslinking times were all between 17 and 25 seconds. Among them, Example 5 exhibited the best processing performance, with a scorch time of 14 seconds and a crosslinking time of 17 seconds. This indicates that the optimized process of the present invention can effectively improve processing performance, avoid scorching, and shorten the crosslinking time, thereby improving production efficiency. Comparative Example 1, lacking a crosslinking aid, had a short scorch time, making it prone to scorching, and a long crosslinking time, resulting in poor processing performance. Comparative Example 3, without employing a gradient heating process, had processing performance and product performance inferior to the Examples, further highlighting the ingenuity of the process design of the present invention.

[0068] In summary, the peroxide crosslinking agent and its production process of the present invention solve many core problems of the prior art through creative raw material system design and process optimization.

[0069] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A peroxide crosslinking agent, characterized in that, The raw materials for preparation consist of α,α'-dihydroxy-1,3-diisopropylbenzene, tert-butyl hydroperoxide, an initiator, a co-crosslinking agent, a regulator, and dichloromethane; the initiator is a compound of acetic acid and perchloric acid mixed at a mass ratio of 1:0.05-0.2; the co-crosslinking agent is a compound of triallyl isocyanurate and vinyltrimethoxysilane at a mass ratio of 1:0.5-1.5, or a compound of triallyl isocyanurate, vinyltrimethoxysilane, and N,N'-m-phenylenebismaleimide at a mass ratio of 1:0.6-1.0:0.4-0.6; the regulator is dibutyltin dilaurate.

2. The peroxide crosslinking agent according to claim 1, characterized in that, The molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to tert-butyl hydroperoxide is 1:1.0-1:2.

0.

3. The peroxide crosslinking agent according to claim 2, characterized in that, The molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the initiator is 1:0.1-1:0.8; the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the co-crosslinking agent is 1:0.2-1:1.5; and the molar ratio of α,α'-dihydroxy-1,3-diisopropylbenzene to the regulator is 1:0.05-1:0.

2.

4. The peroxide crosslinking agent according to claim 1, characterized in that, The amount of dichloromethane used is 5 to 8 times the mass of α,α'-dihydroxy-1,3-diisopropylbenzene.

5. A production process for the peroxide crosslinking agent according to any one of claims 1-4, characterized in that, The process includes raw material pretreatment, oxidation reaction, ring-closure reaction, and post-treatment steps. The raw material pretreatment involves dissolving α,α'-dihydroxy-1,3-diisopropylbenzene in dichloromethane under stirring to obtain a pretreatment solution; tert-butyl hydroperoxide is purified by vacuum distillation; and the initiator, crosslinking agent, and regulator are dried to remove water. The oxidation reaction involves adding the pretreatment solution to a reactor, controlling the initial temperature, adding purified tert-butyl hydroperoxide dropwise, and then adding the initiator and stirring to obtain an intermediate product after a gradient temperature increase. The ring-closure reaction involves adding the crosslinking agent and regulator to the reactor, and then stirring under a gradient temperature increase until the viscosity of the system reaches 150 mPa·s-220 mPa·s at 25°C, rotor No. 2, and 20 r / min, at which point the reaction is stopped, yielding a crude product. The post-treatment involves washing, separating, vacuum distilling, drying, and pulverizing the crude product to obtain the finished product.

6. The production process according to claim 5, characterized in that, The initial temperature of the oxidation reaction is 0℃, the time for adding tert-butyl hydroperoxide is 30min-60min, and after the addition is completed, the temperature is gradually increased to 8℃-10℃ at a rate of 2℃ / h, the stirring speed is 300r / min-450r / min, and the reaction time is 24h-40h.

7. The production process according to claim 5, characterized in that, The closed-loop reaction was carried out by gradually increasing the temperature from 15°C to 20°C at a rate of 3°C / h, with a stirring speed of 400 r / min-550 r / min and a reaction time of 24 h-42 h.

8. The production process according to claim 5, characterized in that, The stirring and dissolving temperature in the raw material pretreatment is 25℃-30℃, and the drying and dehydration temperature is 80℃-85℃; the purification conditions for tert-butyl hydroperoxide are 0.08MPa and 50℃.

9. The production process according to claim 5, characterized in that, The post-treatment involves washing the crude product with deionized water 3-4 times, with each wash using twice the amount of crude product. The vacuum distillation is carried out at a pressure of 0.07-0.08 MPa and a temperature of 60-75℃.

10. The production process according to claim 5, characterized in that, The post-treatment drying conditions are 100℃-110℃, 0.1MPa, and drying time is 4h-7h; the particle size of the finished product after pulverization is 80 mesh-120 mesh.

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