High-dispersion type composite resorcinol master batch and preparation method thereof

Abstract

The invention provides a high-dispersion type composite resorcinol master batch and a preparation method thereof, and relates to the technical field of rubber additives, and the high-dispersion type composite resorcinol master batch comprises the following components in parts by weight: 70-85 parts of resorcinol; 8-15 parts of a composite rubber carrier; 0.5 to 5 parts of modified nano silicon dioxide; 1-3 parts of polylactic acid microspheres; 1-3 parts of modified fatty acid zinc soap; 0-2 parts of an antioxidant; and 0-3 parts of white carbon black. Through the synergistic effect of the composite rubber carrier, the compatibility with resorcinol is remarkably improved; surface modified nano silicon dioxide is introduced and is matched with a modified fatty acid zinc soap system, so that the sublimation and dissipation phenomena of resorcinol in a high-temperature processing process are effectively inhibited; porous polylactic acid microspheres are adopted, and uniform dispersion and controllable release of resorcinol in the mixing process are achieved through physical coating; and a three-stage gradient temperature control internal mixing process is combined to form a stable three-dimensional coating network.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber additives, and in particular to a highly dispersed composite resorcinol masterbatch and a preparation method thereof. Background Art

[0002] Resorcinol, a key adhesive in the rubber industry, is widely used in products such as tires, hoses, and tapes. It reacts with methylene donors to form a cross-linked network, significantly improving the adhesion between rubber and the structural material. However, traditional resorcinol has significant drawbacks when used directly: its easy sublimation leads to the generation of irritating fumes during mixing, posing a threat to the production environment and worker health. Furthermore, resorcinol is prone to oxidation and discoloration during high-temperature processing, and it easily absorbs moisture and clumps during storage, resulting in decreased activity and uneven dispersion, directly impacting the process stability of the rubber compound and the performance of the final product.

[0003] Invention Publication No. CN117487104A discloses a method for preparing a resorcinol-formaldehyde resin that enhances backbone-rubber adhesion. This method uses styrene-butadiene rubber as a carrier, physically coating resorcinol with the resin, and adding additives such as stearic acid and naphthenic oil to produce a masterbatch. This method can reduce dust and processing fumes to a certain extent. However, the masterbatch produced by this method still suffers from low dispersion efficiency and insufficient high-temperature stability. The limited compatibility of the rubber carrier with resorcinol makes it difficult to achieve uniform dispersion of the masterbatch during mixing. Furthermore, at high temperatures, resorcinol may still escape from the carrier, resulting in localized excessive concentration or volatilization losses.

[0004] Invention publication number CN102875754A discloses a modified resorcinol phenolic resin, its preparation method and rubber composition. This solution uses resorcinol formaldehyde resin to reduce the free resorcinol content and reduce processing smoke, but its increased molecular weight leads to an increase in the Mooney viscosity of the rubber, and the resin has strong hygroscopicity, which can easily cause problems such as rubber scorching or interface delamination.

[0005] Invention publication number CN114671741A discloses a resorcinol oligomeric derivative for rubber tires and its masterbatch preparation and application. Although chemical modification of resorcinol by introducing unsaturated hydrocarbons such as styrene can improve the stability of the rubber, the presence of the side group structure exacerbates the delayed heat generation of the rubber compound, affecting its durability in dynamic use scenarios such as tires. Summary of the Invention

[0006] To address the problems of uneven dispersion and high-temperature volatility of resorcinol in existing technologies, the present invention proposes a highly dispersed composite resorcinol masterbatch and its preparation method. This masterbatch significantly improves its compatibility with resorcinol through the synergistic effect of a composite rubber carrier. The introduction of surface-modified nano-silica to directionally anchor resorcinol molecules, combined with a modified fatty acid zinc soap system with dynamic crosslinking properties, effectively inhibits the sublimation and escape of resorcinol during high-temperature processing. The use of porous polylactic acid microspheres as the loading unit for resorcinol allows for uniform dispersion and controlled release of resorcinol during mixing through physical coating, further improving the dispersion efficiency of the active ingredient in the masterbatch. Combined with a three-stage gradient temperature-controlled mixing process, the masterbatch structure is in situ solidified while optimizing the dispersion effect, forming a stable three-dimensional coating network.

[0007] To achieve the above objectives, the present invention provides the following technical solutions: A highly dispersed composite resorcinol masterbatch comprising the following components in parts by weight: 70-85 parts of resorcinol; 8-15 parts of composite rubber carrier; 0.5-5 parts of modified nano-silica; 1-3 parts of polylactic acid microspheres; 1-3 parts of modified fatty acid zinc soap; 0-2 parts of antioxidant; and 0-3 parts of white carbon black.

[0008] Preferably, the composite rubber carrier is composed of liquid rubber, styrene-butadiene rubber, and EPDM in a mass ratio of 6:4:1. The polar molecular segments of the styrene-butadiene rubber and the flexible amorphous molecular segments of the EPDM are blended through the excellent physical and chemical compatibility of the liquid natural rubber, and then mechanically kneaded in an internal mixer to form a three-dimensional interpenetrating network structure at the molecular chain level. This enhances the carrier's physical adsorption capacity for resorcinol at the nanoscale, while simultaneously constructing a gradient coating barrier at the micrometer scale, significantly inhibiting the escape of resorcinol during the high-temperature stage of internal mixing.

[0009] More preferably, the liquid rubber is one or more of liquid recycled rubber, liquid natural rubber, liquid styrene-butadiene rubber, liquid polyisoprene rubber, or liquid butadiene rubber. Liquid rubber serves as both a dispersing agent and a softener. Its low viscosity reduces the interfacial energy of the rubber matrix through an in-situ wetting effect, enhancing the bonding strength between the masterbatch and the rubber matrix and completely eliminating phase separation during processing.

[0010] Preferably, the modified nano-silica is modified with the silane coupling agent KH-550 and has a particle size of 10-50 nm. The anchoring effect of the surface silane groups allows for the targeted adsorption of resorcinol molecules, reducing the tendency of particles to aggregate. Furthermore, the high specific surface area of ​​the nanoparticles forms physical crosslinks with the rubber carrier, further improving the dispersion uniformity of the masterbatch and the dynamic mechanical properties of the rubber compound.

[0011] Preferably, the polylactic acid microspheres have a porosity of 30-50% and a particle size of 50-200 μm. The porous structure of the polylactic acid microspheres enables efficient loading and gradient release of resorcinol. During the initial mixing phase, the surface pores of the microspheres preferentially open, promoting rapid dispersion of resorcinol. As the temperature rises, the internal pores gradually release residual components, avoiding localized oversaturation and volatilization losses caused by concentrated release during the initial processing phase.

[0012] Preferably, the modified fatty acid zinc soap is prepared by mixing C8-C22 unsaturated fatty acids and saturated fatty acids in a mass ratio of 2:1-3:1, followed by reaction with a zinc compound. The resulting product is then modified with a reversible crosslinking modifier. The flexible chain segments of the unsaturated fatty acids and the rigid structure of the saturated fatty acids synergistically regulate the polarity of the zinc soap, enhancing its compatibility with the rubber carrier. The reversible crosslinked network dynamically dissociates at processing temperatures, reducing the migration resistance of the zinc soap. Upon cooling, it recrosslinks to form a stable physical barrier, blocking the sublimation path of resorcinol.

[0013] More preferably, the unsaturated fatty acid is one or more of oleic acid or palmitoleic acid; the saturated fatty acid is one or more of stearic acid or lauric acid; the zinc compound is one or more of zinc oxide or zinc hydroxide; and the reversible crosslinking modifier is one or more of a furan-maleimide derivative or furanamine-grafted zinc ricinoleate. The unsaturated double bonds of oleic acid or palmitoleic acid provide dynamic crosslinking sites, which reversibly react with the furan groups to form a temperature-responsive network. This allows for moderate flow of the zinc soap during the high-temperature mixing stage to optimize dispersion, achieving dual stability in both processing and application scenarios.

[0014] The present invention also provides a method for preparing a highly dispersed composite resorcinol masterbatch, comprising the following steps: (1) adding resorcinol to deionized water and stirring to mix, adding polylactic acid microspheres and ultrasonically dispersing to form a premixed solution, and spray drying the premixed solution to obtain a premix; (2) adding the remaining raw materials into the internal mixer in proportion, controlling the internal mixing temperature in stages, and obtaining the rubber compound; (3) The rubber material is extruded through a twin-screw extruder with seven temperature controls, pelletized, and cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0015] Preferably, the stirring and mixing temperature in step (1) is 60-80°C, the stirring time is 20-30 minutes, and the ultrasonic dispersion time is 15-25 minutes. Gentle heating accelerates the dissolution and diffusion of resorcinol in deionized water while preventing the pore collapse of the polylactic acid microspheres caused by excessive temperature. The precise time window of ultrasonic dispersion ensures that the surface and internal pores of the microspheres are fully loaded with resorcinol, forming a homogeneous premixed system, laying the foundation for gradient release in the subsequent mixing stage.

[0016] Preferably, the first stage of the mixing temperature in step (2) is 60-70°C, the mixing time is 5-10 minutes, the second stage is heated to 70-90°C, the mixing time is 8-10 minutes, and the third stage is cooled to 50-70°C after the premix is ​​added, and the mixing time is 10-15 minutes. The first stage of low-temperature mixing: preliminarily activates the dynamic molecular interpenetrating network of the composite rubber carrier, promotes the uniform dispersion of the modified nano-silica and the fatty acid zinc soap, and avoids premature escape of resorcinol at high temperature; the second stage of heating mixing: stimulates the surface silane group anchoring effect of the nano-silica by shear heat, strengthens its directional adsorption with resorcinol, and at the same time, the reversible network of the dynamically cross-linked modified zinc soap gradually dissociates, releasing fluidity to optimize the dispersion interface; the third stage of cooling mixing: the premix promotes the selective opening of the surface pores of the polylactic acid microspheres under low temperature conditions, realizes the controlled release of resorcinol, and at the same time, the reversible cross-linking network is reformed, solidifies the internal coating structure of the masterbatch, and suppresses the risk of volatilization in subsequent processing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Through the synergistic design of the composite rubber carrier, liquid rubber, styrene-butadiene rubber and EPDM rubber are compounded in proportion to enhance the compatibility with resorcinol and avoid uneven dispersion caused by the polarity difference of the carrier during mixing; high-porosity polylactic acid microspheres are also used to load the sustained-release technology to achieve the gradual release of resorcinol at high mixing temperature, avoiding excessive local concentration of resorcinol and further enhancing the dispersibility of the active ingredient; (2) Through the directional adsorption effect of nano-silica modified by silane coupling agent, hydrogen bonds and physical adsorption are used to fix the resorcinol molecules, thereby inhibiting the migration and escape of the effective ingredients; and through the reversible cross-linking modified fatty acid zinc soap network construction, combined with the optimization of the segmented mixing process, a dynamic cross-linking network is formed at the processing temperature to encapsulate the resorcinol, restricting its free migration. After cooling, the network is reconstructed, significantly reducing the high-temperature volatilization loss; (3) Through the synergistic lubrication and anti-hygroscopic composite design of liquid rubber, the viscosity and Mooney stability of the rubber compound are balanced, and the synergistic effect of the hydrophobic pores of polylactic acid microspheres and the hydrophobic surface of modified fatty acid zinc soap is utilized to reduce the risk of moisture absorption and agglomeration of the masterbatch. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to specific embodiments.

[0019] Example 1 This embodiment provides a total highly dispersed composite resorcinol masterbatch formula, specifically comprising the following components in parts by weight: 70-85 parts of resorcinol; 8-15 parts of composite rubber carrier; 0.5-5 parts of modified nano-silica; 1-3 parts of polylactic acid microspheres; 1-3 parts of modified fatty acid zinc soap; 0-2 parts of antioxidant; and 0-3 parts of white carbon black.

[0020] In some preferred embodiments, the composite rubber carrier is composed of liquid rubber, styrene-butadiene rubber, and EPDM in a mass ratio of 6:4:1. The technical effect is that the polar molecular segments of the styrene-butadiene rubber and the flexible molecular segments of the amorphous region of the EPDM are blended through the excellent physical and chemical compatibility of the liquid natural rubber, and then mechanically kneaded in an internal mixer, forming a three-dimensional interpenetrating network structure at the molecular chain level. This enhances the carrier's physical adsorption capacity for resorcinol at the nanoscale, while simultaneously creating a gradient coating barrier at the micrometer scale, significantly inhibiting the escape of resorcinol during the high-temperature stage of internal mixing.

[0021] In some preferred embodiments, the liquid rubber is one or more of liquid recycled rubber, liquid natural rubber, liquid styrene-butadiene rubber, liquid polyisoprene rubber, or liquid butadiene rubber. Liquid rubber serves as both a dispersing agent and a softener. Its low viscosity reduces the interfacial energy of the rubber matrix through an in-situ wetting effect, enhancing the bonding strength between the masterbatch and the rubber matrix and completely eliminating phase separation during processing.

[0022] In some preferred embodiments, the modified nano-silica is modified with the silane coupling agent KH-550 and has a particle size of 10-50 nm. The technical benefit lies in the targeted adsorption of resorcinol molecules through the anchoring effect of the surface silane groups, reducing the tendency of particles to aggregate. Furthermore, the high specific surface area of ​​the nanoparticles forms physical crosslinks with the rubber carrier, further improving the dispersion uniformity of the masterbatch and the dynamic mechanical properties of the rubber compound.

[0023] In some preferred embodiments, the polylactic acid microspheres have a porosity of 30-50% and a particle size of 50-200 μm. The technical benefit lies in the fact that the porous structure of the polylactic acid microspheres enables efficient loading and gradient release of resorcinol. During the initial mixing phase, the surface pores of the microspheres preferentially open, promoting rapid dispersion of the resorcinol. As the temperature rises, the internal pores gradually release residual components, avoiding localized oversaturation and volatilization losses caused by concentrated release during the initial processing phase.

[0024] In some preferred embodiments, the modified fatty acid zinc soap is prepared by mixing C8-C22 unsaturated fatty acids and saturated fatty acids in a mass ratio of 2:1-3:1, reacting with a zinc compound, and then co-modifying the resulting product with a reversible crosslinking modifier. The technical benefit lies in the fact that the flexible chain segments of the unsaturated fatty acids and the rigid structure of the saturated fatty acids synergistically regulate the polarity of the zinc soap, enhancing its compatibility with the rubber carrier. The reversible crosslinked network dynamically dissociates at processing temperatures, reducing the zinc soap's migration resistance, and re-crosslinks upon cooling, forming a stable physical barrier that blocks the sublimation of resorcinol.

[0025] In some more preferred embodiments, the unsaturated fatty acid is one or more of oleic acid or palmitoleic acid; the saturated fatty acid is one or more of stearic acid or lauric acid; the zinc compound is one or more of zinc oxide or zinc hydroxide; and the reversible crosslinking modifier is one or more of a furan-maleimide derivative or furanamine-grafted zinc ricinoleate. The technical advantage is that the unsaturated double bonds of oleic acid or palmitoleic acid provide dynamic crosslinking sites, which reversibly react with the furan groups to form a temperature-responsive network. This allows the zinc soap to flow moderately during the high-temperature mixing stage to optimize dispersion, achieving dual stability in both processing and application scenarios.

[0026] This embodiment also provides a method for preparing a total highly dispersed composite resorcinol masterbatch, which specifically comprises the following steps: (1) adding resorcinol to deionized water and stirring to mix, adding polylactic acid microspheres and ultrasonically dispersing to form a premixed solution, and spray drying the premixed solution to obtain a premix; (2) adding the remaining raw materials into the internal mixer in proportion, controlling the internal mixing temperature in stages, and obtaining the rubber compound; (3) The rubber material is extruded through a twin-screw extruder with seven temperature controls, pelletized, and cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0027] In some preferred implementation cases, the stirring and mixing temperature in step (1) is 60-80°C, the stirring time is 20-30 minutes, and the ultrasonic dispersion time is 15-25 minutes. The technical effect is that the dissolution and diffusion of resorcinol in deionized water is accelerated by gentle heating, while avoiding the collapse of the pores of the polylactic acid microspheres caused by excessive temperature; the precise time window of ultrasonic dispersion ensures that the surface and internal pores of the microspheres are fully loaded with resorcinol, forming a homogeneous premixed system, laying the foundation for the gradient release in the subsequent mixing stage.

[0028] In some preferred implementation cases, the mixing temperature in the first stage of step (2) is 60-70°C, the mixing time is 5-10 min, the temperature is raised to 70-90°C in the second stage, the mixing is carried out for 8-10 min, and the temperature is lowered to 50-70°C after the premix is ​​added in the third stage, and the mixing is carried out for 10-15 min. Its technical effects are as follows: the first stage of low-temperature mixing: preliminarily activates the dynamic molecular interpenetrating network of the composite rubber carrier, promotes the uniform dispersion of modified nano-silica and fatty acid zinc soap, and avoids premature dispersion of resorcinol at high temperature; the second stage of temperature-raising mixing: stimulates the surface silane group anchoring effect of nano-silica through shear heat, strengthens its directional adsorption with resorcinol, and at the same time gradually dissociates the reversible network of the dynamically cross-linked modified zinc soap, releasing fluidity to optimize the dispersion interface; the third stage of temperature-lowering mixing: the premix promotes the selective opening of the surface pores of the polylactic acid microspheres under low temperature conditions, realizes the controlled release of resorcinol, and at the same time the reversible cross-linking network is reformed, solidifies the internal coating structure of the masterbatch, and suppresses the risk of volatilization in subsequent processing.

[0029] Example 2 This embodiment provides a highly dispersed composite resorcinol masterbatch, specifically comprising the following components in parts by weight: 75 parts of resorcinol; 10 parts of composite rubber carrier; 3 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0030] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 2:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0031] This embodiment also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically includes the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0032] Example 3 This embodiment provides a highly dispersed composite resorcinol masterbatch, specifically comprising the following components in parts by weight: 75 parts of resorcinol; 15 parts of composite rubber carrier; 2 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0033] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 3:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0034] This embodiment also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically includes the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0035] Example 4 This embodiment provides a highly dispersed composite resorcinol masterbatch, specifically comprising the following components in parts by weight: 85 parts of resorcinol; 15 parts of composite rubber carrier; 2 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0036] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 3:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0037] This embodiment also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically includes the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0038] Example 5 This embodiment provides a highly dispersed composite resorcinol masterbatch, specifically comprising the following components in parts by weight: 70 parts of resorcinol; 8 parts of composite rubber carrier; 1 part of modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 2 parts of antioxidant; and 3 parts of white carbon black.

[0039] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 3:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0040] This embodiment also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically includes the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0041] Comparative Example 1 The difference between this comparative example and Example 2 is that this comparative example uses styrene-butadiene rubber instead of the composite rubber.

[0042] This comparative example provides a highly dispersed composite resorcinol masterbatch, which specifically includes the following components in parts by weight: 75 parts of resorcinol; 10 parts of styrene-butadiene rubber; 3 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0043] The modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 2:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0044] This comparative example also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically comprises the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0045] Comparative Example 2 The difference between this comparative example and Example 2 is that polylactic acid microspheres are not added to the formula of this comparative example.

[0046] This comparative example provides a highly dispersed composite resorcinol masterbatch, which specifically includes the following components in parts by weight: 75 parts of resorcinol; 10 parts of composite rubber carrier; 3 parts of KH-550 modified nano-silica; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0047] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 2:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0048] This comparative example also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically comprises the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in a certain proportion and stirred at 70°C for 20 min to form a premix solution, which was then spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0049] Comparative Example 3 The difference between this comparative example and Example 2 is that the fatty acid zinc soap in this comparative example is not modified by blending with furan-maleimide derivatives.

[0050] This comparative example provides a highly dispersed composite resorcinol masterbatch, which specifically includes the following components in parts by weight: 75 parts of resorcinol; 10 parts of composite rubber carrier; 3 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0051] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 2:1 and reacting with zinc oxide; the antioxidant is antioxidant 1010.

[0052] This comparative example also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically comprises the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: Add the remaining raw materials into the mixer in proportion, and control the mixing temperature in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. In the second stage, the temperature is raised to 90°C and mixed for 10 min. In the third stage, the premix is ​​added and the temperature is lowered to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0053] Comparative Example 4 The difference between this comparative example and Example 2 is that in the preparation method of this comparative example, the premix and the remaining materials are added to the internal mixer together, and the premix is ​​not added in the third stage.

[0054] This comparative example provides a highly dispersed composite resorcinol masterbatch, which specifically includes the following components in parts by weight: 75 parts of resorcinol; 10 parts of composite rubber carrier; 3 parts of KH-550 modified nano-silica; 2 parts of polylactic acid microspheres; 2 parts of modified fatty acid zinc soap; 1 part of antioxidant; and 2 parts of white carbon black.

[0055] The composite rubber carrier is composed of liquid recycled rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:1; the modified fatty acid zinc soap is prepared by mixing oleic acid and stearic acid in a mass ratio of 2:1 and reacting with zinc oxide, and the resulting product is modified by blending with a furan-maleimide derivative; the antioxidant is antioxidant 1010.

[0056] This comparative example also provides a method for preparing a highly dispersed composite resorcinol masterbatch, which specifically comprises the following steps: (1) Premixing and dispersion: Resorcinol was added to deionized water in proportion and stirred at 70°C for 20 min. Polylactic acid microspheres were added and ultrasonically dispersed for 20 min to form a premix solution. The premix solution was spray-dried to obtain a premix; (2) Segmented mixing: The premix and the remaining raw materials are added to the mixer in proportion, and the mixing temperature is controlled in stages. The mixing temperature in the first stage is 60°C, and the mixing time is 10 min. The second stage is heated to 90°C and mixed for 10 min. The third stage is cooled to 70°C and mixed for 10 min to obtain the rubber compound. (3) Extrusion granulation: The rubber material is extruded through a twin-screw extruder with seven temperature-controlled sections, with the temperatures being 25-60°C, 60-70°C, 70-80°C, 80-90°C, 80-95°C, 95-80°C, and 80-70°C, respectively. After pelletizing, the material is cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

[0057] Test example The composite resorcinol masterbatch prepared by the formula and method of Examples 2-5 and Comparative Examples 1-4 was tested for its dispersibility, high-temperature dissipation rate, volatile loss rate, and storage stability. The results are shown in Table 1. The test standards are as follows: 1. Dispersibility: Observe the cross-sectional structure of the masterbatch. Rating criteria: uniform without aggregation, local aggregation, obvious agglomeration; 2. High temperature dissipation rate: Place the masterbatch in a 150°C oven for 1 hour and measure the percentage of mass loss; 3. Volatility loss rate: dry the masterbatch at 105°C for 24 hours and calculate the mass loss percentage; 4. Storage stability: The masterbatch was stored at a humidity of 60% and a temperature of 25°C for 30 days, and the agglomeration rate of the masterbatch was measured.

[0058] Table 1

[0059] As shown in Table 1, the highly dispersed composite resorcinol masterbatches prepared using the technical solution of the present invention exhibit excellent overall performance. Resorcinol is evenly dispersed within the masterbatch without aggregation, and the high-temperature dissipation rate and volatile loss rate are significantly lower than those of traditional processes. Furthermore, the masterbatch agglomeration rate during storage is less than 3%.

[0060] In Comparative Example 1, replacing the composite carrier with a single styrene-butadiene rubber (SBR) resulted in localized aggregation of the masterbatch dispersion, significantly increased high-temperature dissipation rate and volatile loss rate, and significantly increased agglomeration rate. Due to the lack of the high fluidity of the liquid rubber and the flexible nonpolar segments of the EPDM rubber, the carrier's compatibility with resorcinol decreased. The polarity difference during mixing led to phase separation, and the rigid carrier structure exacerbated the migration and escape of resorcinol.

[0061] In Comparative Example 2, the masterbatch without PLA microspheres exhibited significantly increased agglomeration and volatile loss during storage. The absence of PLA microspheres resulted in the loss of physical adsorption and high-temperature sustained-release carriers for resorcinol. This resulted in excessive local concentration gradients during mixing, leading to rapid release of the active ingredient and subsequent moisture absorption and agglomeration. Furthermore, the escape pathway was not effectively blocked.

[0062] Comparative Example 3, which did not use the fatty acid zinc soap modified with the furan-maleimide derivative, had a significantly lower high-temperature dissipation rate and volatile loss rate than Example 2. The lack of a dynamic cross-linking network prevented effective encapsulation of resorcinol at processing temperatures, exacerbating volatile losses due to free migration. Furthermore, the unreconstructed cross-linking network was unable to inhibit the migration of the active ingredient during storage.

[0063] In Comparative Example 4, after the premix and remaining raw materials were added to the internal mixer all at once, the masterbatch exhibited localized aggregation, resulting in increased dispersibility and agglomeration. The failure to adopt a staged internal mixing process resulted in concentrated release of resorcinol in the high-temperature zone, preventing the carrier structure from fully solidifying. Some components volatilized due to premature exposure to high temperatures, and the incomplete dispersion of resorcinol exacerbated the risk of moisture absorption and agglomeration.

[0064] Unless otherwise specified, the raw materials and equipment used in this invention are commonly used in the art. Unless otherwise specified, the methods used in this invention are conventional methods in the art. The foregoing description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modifications, variations, and equivalent conversions of the above embodiments based on the technical essence of the present invention remain within the scope of protection of the technical solutions of the present invention.

Claims

1. A highly dispersed composite resorcinol masterbatch, characterized in that: Contains the following components in parts by weight: 70-85 parts of resorcinol; 8-15 parts of composite rubber carrier; 0.5-5 parts of modified nano-silica; 1-3 parts of polylactic acid microspheres; 1-3 parts of modified fatty acid zinc soap; 0-2 parts of antioxidant; and 0-3 parts of white carbon black.

2. A highly dispersed composite resorcinol masterbatch according to claim 1, characterized in that: The composite rubber carrier is composed of liquid rubber, styrene-butadiene rubber and EPDM rubber in a mass ratio of 6:4:

1.

3. A highly dispersed composite resorcinol masterbatch according to claim 2, characterized in that: The liquid rubber is one or more of liquid recycled rubber, liquid natural rubber, liquid styrene-butadiene rubber, liquid polyisoprene rubber or liquid butadiene rubber.

4. The highly dispersed composite resorcinol masterbatch according to claim 1, characterized in that: The modified nano-silica is modified by silane coupling agent KH-550 and has a particle size of 10-50 nm.

5. The highly dispersed composite resorcinol masterbatch according to claim 1, characterized in that: The polylactic acid microspheres have a porosity of 30-50% and a particle size of 50-200 μm.

6. The highly dispersed composite resorcinol masterbatch according to claim 1, characterized in that: The modified fatty acid zinc soap is prepared by mixing C8-C22 unsaturated fatty acids and saturated fatty acids in a mass ratio of 2:1-3:1, reacting with a zinc compound, and mixing and modifying the obtained product with a reversible cross-linking modifier.

7. The highly dispersed composite resorcinol masterbatch according to claim 6, characterized in that: The unsaturated fatty acid is one or more of oleic acid or palmitoleic acid; the saturated fatty acid is one or more of stearic acid or lauric acid; the zinc compound is one or more of zinc oxide or zinc hydroxide; and the reversible cross-linking modifier is one or more of furan-maleimide derivatives or furfural methylamine-grafted ricinoleic acid zinc.

8. A method for preparing the highly dispersed composite resorcinol masterbatch according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) adding resorcinol to deionized water and stirring to mix, adding polylactic acid microspheres, and ultrasonically dispersing to form a premixed solution, and spray drying the premixed solution to obtain a premix; (2) adding the remaining raw materials into the internal mixer in proportion, controlling the internal mixing temperature in stages, and obtaining the rubber compound; (3) The rubber material is extruded through a twin-screw extruder with seven temperature controls, pelletized, and cooled to room temperature to obtain a highly dispersed composite resorcinol masterbatch.

9. The method for preparing a highly dispersed composite resorcinol masterbatch according to claim 8, wherein: The stirring and mixing temperature in step (1) is 60-80° C., the stirring time is 20-30 min, and the ultrasonic dispersion time is 15-25 min.

10. The method for preparing a highly dispersed composite resorcinol masterbatch according to claim 8, characterized in that: In the step (2), the first stage of the banburying temperature is 60-70°C, the mixing time is 5-10 minutes, the second stage is heated to 70-90°C, the mixing time is 8-10 minutes, and the third stage is cooled to 50-70°C after the premix is ​​added, and the mixing time is 10-15 minutes.

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