A p-aramid activation agent, activated p-aramid and preparation method

Abstract

This invention relates to a para-aramid activator, activated para-aramid, and its preparation method, belonging to the field of para-aramid processing technology. By weight, the para-aramid activator comprises the following components: 2-5 parts epoxy resin; 0.1-0.4 parts sulfosuccinate wetting and penetrating agent; 1-4 parts smoothing agent; 1-4 parts softening agent; and 80-100 parts deionized water. The para-aramid activator is introduced into an oiling tank; para-aramid fibers are fixed on the upper and lower oiling rollers of an oiling machine, and oiling is performed to obtain activated para-aramid. A frequency difference is provided between the upper and lower oiling rollers. The para-aramid activator can improve fiber softness, reduce processing losses, and the activated para-aramid product combines low friction and high activation activity, making it suitable for large-scale continuous production.

Description

Technical Field

[0001] This invention relates to a para-aramid activator, activated para-aramid, and preparation method, belonging to the field of para-aramid processing technology. Background Technology

[0002] Para-aramid (poly(p-phenylene terephthalamide),) is a high-performance fiber widely used in many fields due to its high strength, high modulus, and high temperature resistance. However, its inherent chemical inertness and smooth surface pose challenges when compounded with resin matrices or subjected to subsequent processing. Surface activation treatment becomes a necessary step to improve its interfacial bonding properties.

[0003] Existing activation technologies mainly fall into two categories: chemical modification and physical modification. Chemical modification methods, such as surface activation and copolymerization modification, can introduce active groups, but often involve strong acids, strong bases, or organic solvents, leading to environmental pollution and high costs. Physical modification methods, such as plasma treatment and high-energy irradiation, are relatively clean, but usually require expensive specialized equipment, are complex to operate, and the uniformity and durability of the treatment effect are difficult to guarantee. These methods largely remain at the laboratory stage and cannot meet the requirements of continuous and stable industrial production.

[0004] Existing para-aramid activation technology still faces a significant processing challenge. After activation and oiling, the fibers are prone to fuzzing and breakage during subsequent twisting and weaving processes due to the increased surface friction coefficient and insufficient flexibility. This not only results in low yield but also severely impacts production efficiency and product quality.

[0005] To address the aforementioned issues, industrial processes often incorporate smoothing agents and antistatic agents into activators. For instance, existing technologies use high concentrations (e.g., 65%–85%) of lubricant to reduce friction or synthetic ester smoothers to improve penetration and wettability. However, these solutions are often complex and costly, focusing on optimizing a single function and failing to effectively balance the fiber's "activation" and "softening" requirements, resulting in limited improvement in issues such as twisted fuzz and fiber breakage. Therefore, developing a low-cost, simple process for para-aramid fiber treatment that simultaneously achieves efficient activation and excellent processing performance is crucial for promoting its large-scale application. Summary of the Invention

[0006] This invention addresses the problems of high cost, large fiber friction coefficient, and easy fuzzing and breakage during twisting of existing para-aramid activation systems. It provides a para-aramid activator, activated para-aramid, and preparation method. The para-aramid activator can improve fiber flexibility and reduce processing losses. The activated para-aramid finished product has both low friction and high activation activity, making it suitable for large-scale continuous production.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a para-aramid activator, which, by weight, comprises the following components: 2-5 parts epoxy resin; 0.1-0.4 parts of sulfosuccinate wetting and penetrating agent; 1-4 parts of smoothing agent; Fabric softener 1-4 parts; 80-100 parts deionized water.

[0008] Furthermore, the epoxy resin is at least one of E51, glycerol diglycidyl ether, and glycerol triglycidyl ether.

[0009] Furthermore, the sulfosuccinate wetting and penetrating agent is sodium diisooctyl sulfosuccinate.

[0010] Further, the smoothing agent is at least one of trimethylolpropane trioleate, pentaerythritol tetraoleate, isooctyl stearate, and erucamide.

[0011] Further, the fabric softener is at least one of PEG 400 monooleate, PEG 600 monostearate, and glyceryl monostearate.

[0012] Further, the mass ratio of the epoxy resin to the fabric softener is 1:(0.5-1.5). The mass ratio of the smoothing agent to the softening agent is 1:(0.5-2.0); The total mass ratio of the smoothing agent and the softening agent to the epoxy resin is (1.5-2.5):1; The mass ratio of the epoxy resin to the sulfosuccinate wetting and penetrating agent is 1:(0.05-0.12).

[0013] The present invention also discloses an activated para-aramid fiber, comprising para-aramid fibers and an oil film attached to the surface of the para-aramid fibers, wherein the oil film is formed by applying the para-aramid activator of the present invention.

[0014] Furthermore, the oiling rate of the activated para-aramid is 5.6%-6.4%.

[0015] This invention also discloses a method for preparing activated para-aramid fibers, the method comprising: The para-aramid activator described in this invention is used; The para-aramid activator is introduced into the upper oil tank; Para-aramid fibers are fixed on the upper and lower oil rollers of an oiling machine, and the machine is started to apply oil to obtain activated para-aramid fibers. A frequency difference is provided between the upper and lower oil rollers.

[0016] Furthermore, the frequency of the upper oil roller is 5-20Hz, and the frequency of the lower oil roller is 2%-4% slower than the frequency of the upper oil roller.

[0017] The beneficial effects of this invention are: The para-aramid activator, activated para-aramid, and preparation method described in this invention are low-cost, environmentally friendly, and suitable for continuous industrial production. This invention uses deionized water as the main medium, combined with low-content epoxy resin, sulfosuccinate wetting and penetrating agents, smoothing agents, and softeners. The raw materials are inexpensive, the formulation is simple, and highly toxic organic solvents are not required, significantly reducing raw material and environmental treatment costs. Simultaneously, it is compatible with existing oiling machines for continuous production, resulting in high production efficiency and further reducing overall production costs. It significantly inhibits fuzzing and fiber breakage, improving the yield of para-aramid. This invention, by compounding smoothing agents and softeners in the epoxy activation system, forms a uniform, soft, and low-friction oil film on the surface of para-aramid, effectively reducing friction between fibers and between fibers and equipment. This significantly improves the defects of hard, brittle, and easily fuzzing fibers after activation, completely solving the problems of fuzzing and fiber breakage during twisting, greatly increasing the yield and reducing production losses. Moreover, the process is simple and suitable for continuous industrial production.

[0018] The various activator components in the para-aramid activator of this invention exhibit synergistic effects, achieving both high activation activity and excellent processing performance. This invention combines a smoothing agent and a softener in the epoxy activation system, and the appropriate ratio between the epoxy resin, softener, smoothing agent, and sulfosuccinate wetting and penetrating agent achieves better synergistic effects. The long-chain ester structure of the softener is embedded in the epoxy crosslinking network, playing a role in molecular spacing and plasticizing—retaining the active epoxy groups while preventing excessive crosslinking and curing, achieving a balanced effect of "activation without brittleness." The smoothing agent mainly reduces the coefficient of dynamic friction between the fiber and metal equipment, while the softener improves the flexibility of the fiber itself and forms a uniform oil film. Their synergistic effect allows the fiber to pass smoothly through the guide opening during twisting and withstand bending deformation without internal damage, fundamentally solving the problems of hard, brittle, and easily broken fibers after activation.

[0019] The para-aramid activator described in this invention is water-based. Although this high-water, low-oil system achieves low cost and environmental friendliness, the high surface tension of water and the smooth, hydrophobic surface of para-aramid make it difficult for the activator to effectively wet and penetrate into the fiber bundle in traditional oiling processes. This easily leads to uneven surface activation problems, such as "sufficient oil on the outer layer and dryness inside." At the same time, the combination of smoothing and softening agents in the activator not only imparts low friction and high flexibility to the fiber but also makes the fiber bundle surface smoother. If oiling is done using only conventional constant-speed rollers, the fiber bundle lacks sufficient lateral disturbance between the rollers, making it difficult for the oil to overcome capillary resistance and penetrate deep into the gaps between the monofilaments. The method for preparing active para-aramid described in this invention utilizes the frequency difference between the upper and lower rollers to induce weak lateral shearing and slight rubbing of the filament bundle during the pressure applied between the rollers. This rubbing force synergizes with the low surface tension, high permeability, and excellent lubricity of the activator: on the one hand, the low surface tension of the activator itself makes it easier for the oil to spread and propagate along the gaps between the monofilaments under the rubbing action; on the other hand, the lubrication and flexibility properties imparted to the fiber bundle by the activator ensure that the filament bundle can slide smoothly and be evenly pressured without causing localized scratching or hard damage during rubbing. The rubbing force provides the penetration driving force, while the interfacial and lubricating properties of the activator ensure that this driving force is efficiently and safely converted into a capillary penetration effect, allowing the surface oil to penetrate evenly inward along the gaps between the monofilaments, achieving overall uniform activation from the surface to the interior. This ensures that each monofilament inside the fiber bundle is fully activated, resulting in strong adhesion and no localized failure when compounded with the matrix later.

[0020] The activated para-aramid obtained by this invention has the advantages of low friction, high flexibility, anti-fraying, high activation activity, and low cost. It can be widely used in rubber reinforcement, industrial fabrics, friction materials, protective products and other fields, and is especially suitable for large-scale, low-cost application scenarios. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] A para-aramid activator, comprising, by weight, the following components: 2-5 parts epoxy resin; 0.1-0.4 parts of sulfosuccinate wetting and penetrating agent; 1-4 parts of smoothing agent; Fabric softener 1-4 parts; 80-100 parts deionized water.

[0024] Preferably, the para-aramid activator comprises the following components in parts by weight: The epoxy resin is 2 parts, the sulfosuccinate wetting and penetrating agent is 0.2-0.4 parts, the smoothing agent is 1-2 parts, the fabric softener is 2-3 parts, and the deionized water is 92-96 parts.

[0025] Specifically, the epoxy resin is at least one of E51, glycerol diglycidyl ether, and glycerol triglycidyl ether.

[0026] Specifically, the sulfosuccinate wetting and penetrating agent is sodium diisooctyl sulfosuccinate.

[0027] More specifically, the sulfosuccinate wetting and penetrating agent is selected from at least one of OT-75 and DOSS-75.

[0028] Specifically, the smoothing agent is at least one of trimethylolpropane trioleate, pentaerythritol tetraoleate, isooctyl stearate, and erucamide.

[0029] Specifically, the fabric softener is at least one of PEG 400 monooleate, PEG 600 monostearate, and glyceryl monostearate.

[0030] Specifically, the mass ratio of the epoxy resin to the softener is 1:(0.5-1.5). The epoxy resin introduces active groups onto the surface of the para-aramid fiber, but excessive amounts can lead to excessively high crosslinking density and a brittle fiber surface. The softener, through its long-chain ester structure, embeds itself within the epoxy crosslinking network, acting as a molecular spacer and plasticizer. When the ratio of epoxy to softener is within this range, the softener is just sufficient to inhibit excessive crosslinking and curing of the epoxy without diluting the surface density of the epoxy active groups due to excess, thus imparting excellent softness to the fiber while retaining the activation effect.

[0031] Specifically, the mass ratio of the smoothing agent to the softening agent is 1:(0.5-2.0). The smoothing agent mainly reduces the coefficient of dynamic friction between the fiber and the metal equipment, while the softening agent improves the flexibility of the fiber itself and forms a uniform and dense oil film. When the ratio is within this range, the external lubrication provided by the smoothing agent and the internal softening provided by the softening agent complement each other, allowing the fiber to pass smoothly through the guide opening during twisting while withstanding bending deformation without internal damage. If the proportion of smoothing agent is too high, the fiber surface will be too slippery and the oil film too hard, resulting in insufficient resistance to bending fatigue; if the proportion of softening agent is too high, the reduction in the coefficient of dynamic friction will be limited, and the fiber will still easily produce fuzz when passing through the guide opening.

[0032] Specifically, the total mass ratio of the smoothing agent and the softening agent to the epoxy resin is (1.5-2.5):1; this ratio allows for the synergistic effect of the functional components and the activating components. The core technical idea of ​​this invention is to impart excellent processing properties to fibers by compounding smoothing agents and softening agents under relatively low epoxy content conditions. When the total amount of smoothing agent and softening agent is within this range, the activator can form a continuous and uniform functional oil film on the fiber surface, effectively suppressing twisting and fuzzing; at the same time, it will not be excessive and dilute or shield the activating effect of the epoxy resin. If the total amount of functional components (smoothing agent and softening agent) is too low, the oil film will be discontinuous, the fiber will lack local protection, and the fuzzing problem will still be prominent; if the total amount of functional components is too high, the fiber surface will be over-covered, and the bonding strength will decrease when compounded with the matrix later.

[0033] Specifically, the mass ratio of the epoxy resin to the sulfosuccinate wetting and penetrating agent is 1:(0.05-0.12). This ratio ensures stable dispersion of the oil agent in a high-water system. Within this range, the penetrating agent fully emulsifies the epoxy resin into tiny, uniformly sized droplets, thereby promoting the uniform dispersion of the smoothing agent and softener in the aqueous phase, forming a long-term stable oil-in-water emulsion. Simultaneously, the penetrating agent effectively reduces the interfacial tension between the oil agent and the aramid fiber, facilitating the uniform spreading of the smoothing agent and softener. This results in multiple excellent properties, including high stability, high activation activity, low friction, high softness, and anti-snagging.

[0034] More specifically, the preparation method of the para-aramid activator is as follows: Step 1: Weigh 2-5 parts epoxy resin, 0.1-0.4 parts sulfosuccinate wetting and penetrating agent and 80-100 parts deionized water according to the weight ratio, and stir at 45-55℃ for 2-4 hours to obtain solubilized epoxy activating oil. Step 2: Cool the solubilized epoxy activating oil obtained in Step 1 to 20-30℃, add 1-4 parts of smoothing agent and 1-4 parts of softening agent, and stir at 20-30℃ for 2-4 hours to obtain the para-aramid activator.

[0035] The present invention also discloses an activated para-aramid fiber, comprising para-aramid fibers and an oil film attached to the surface of the para-aramid fibers, wherein the oil film is formed by applying the para-aramid activator of the present invention.

[0036] Specifically, the oiling rate of the activated para-aramid is 5.6%-6.4%.

[0037] The process employs segmented liquid preparation, low-temperature compounding, and continuous oiling, which makes the process parameters easy to control and has good stability. It is compatible with existing oiling machines for continuous production, resulting in high production efficiency and further reducing overall production costs.

[0038] This invention also discloses a method for preparing activated para-aramid fibers, the method comprising: The para-aramid activator described in this invention is used; The para-aramid activator is introduced into the upper oil tank; Para-aramid fibers are fixed on the upper and lower oil rollers of an oiling machine, and the machine is started to apply oil to obtain activated para-aramid fibers. A frequency difference is provided between the upper and lower oil rollers.

[0039] Specifically, the starting speed of the oiling machine is 70-120 m / min; The upper oiling roller operates at a frequency of 5-20Hz, while the lower oiling roller operates at a frequency 2%-4% lower than the upper oiling roller. During the compression process between the rollers, the filament bundle experiences weak lateral shearing and slight rubbing. The surface oil penetrates capillarily into the filament bundle along the gaps between the individual filaments, improving the overall activation uniformity of the filament bundle and preventing a situation where the outer layer is sufficiently oiled while the interior is dry, leading to localized failure during later lamination and bonding. Excessive frequency difference can result in excessive twisting force between the rollers, causing damage to the aramid fiber structure.

[0040] More specifically, in this embodiment of the invention, para-aramid fibers with a linear density of 1000D are used, but this does not constitute a limitation of the invention.

[0041] Example 1: Preparation of activated para-aramid.

[0042] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 93.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0043] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0044] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. The starting speed of the oiling machine is 100m / min. The para-aramid is oiled by starting the machine to obtain activated para-aramid.

[0045] Example 2: Preparation of activated para-aramid.

[0046] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of glycerol diglycidyl ether (Shanghai Aladdin), 0.2 parts of OT-75 and 92.8 parts of deionized water were stirred at 50°C for 2.5h to obtain solubilizing epoxy activating oil.

[0047] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 3 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0048] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the upper oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 2% slower than that of the upper oil roller. The starting speed of the oiling machine is 120m / min. The para-aramid is oiled by starting the machine to obtain activated para-aramid.

[0049] Example 3: Preparation of activated para-aramid.

[0050] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of glycerol triglycidyl ether (Shanghai Aladdin), 0.2 parts of OT-75 and 94.8 parts of deionized water were stirred at 50°C for 2.5h to obtain solubilizing epoxy activating oil.

[0051] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 1 part of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0052] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 2.5% slower than that of the upper oil roller. The starting speed of the oiling machine is 110m / min. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0053] Example 4: Preparation of activated para-aramid.

[0054] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of glycerol diglycidyl ether, 0.2 parts of OT-75 and 94.8 parts of deionized water are stirred at 55°C for 3 hours to obtain solubilizing epoxy activating oil.

[0055] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 1 part of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 3 hours to obtain the activator.

[0056] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 2.5% slower than that of the upper oil roller. The starting speed of the oiling machine is 95m / min. The para-aramid is oiled by starting the machine to obtain activated para-aramid.

[0057] Example 5: Preparation of activated para-aramid.

[0058] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 3 parts of E51, 0.36 parts of DOSS-75 and 90.64 parts of deionized water were stirred at 55°C for 3 hours to obtain solubilizing epoxy activating oil.

[0059] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 3 parts of pentaerythritol tetraoleate and 3 parts of PEG 400 monooleate were added. The mixture was stirred at 30°C for 3 hours to obtain the activator.

[0060] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 20Hz, and the frequency of the lower oil roller is 4% slower than that of the upper oil roller. The starting speed of the oiling machine is 80m / min. The para-aramid is oiled by starting the machine to obtain activated para-aramid.

[0061] Example 6: Preparation of activated para-aramid.

[0062] A method for preparing activated para-aramid fibers, the specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 5 parts of glycerol diglycidyl ether, 0.25 parts of DOSS-75 and 86.75 parts of deionized water were stirred at 55°C for 3 hours to obtain solubilizing epoxy activating oil.

[0063] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 4 parts of isooctyl stearate and 4 parts of glyceryl monostearate were added. The mixture was stirred at 30°C for 3 hours to obtain the activator.

[0064] (3) Preparation of low-cost activated para-aramid: The activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 5Hz, and the frequency of the lower oil roller is 2% slower than that of the upper oil roller. The starting speed of the oiling machine is 100m / min. The para-aramid is oiled by starting the machine to obtain activated para-aramid.

[0065] Comparative Example 1: Preparation of activated para-aramid.

[0066] Activated para-aramid fibers were prepared using the same method as in Example 1, except that no smoothing agent or softener was added in this Comparative Example 1.

[0067] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 97.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil, which is the activator.

[0068] (2) Preparation of low-cost activated para-aramid: The activator is introduced into the upper oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0069] Comparative Example 2: Preparation of activated para-aramid.

[0070] Activated para-aramid fibers were prepared using the same method as in Example 1, except that no softener was added in Comparative Example 2.

[0071] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 95.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0072] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0073] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0074] Comparative Example 3: Preparation of activated para-aramid.

[0075] Activated para-aramid fibers were prepared using the same method as in Example 1, except that no smoothing agent was added in Comparative Example 3.

[0076] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 95.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0077] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0078] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0079] Comparative Example 4: Preparation of activated para-aramid.

[0080] Activated para-aramid fibers were prepared using the same method as in Example 1, except that the amount of sulfosuccinate wetting and penetrating agent added was increased in Comparative Example 4.

[0081] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.6 parts of OT-75 and 93.4 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0082] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0083] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0084] Comparative Example 5: Preparation of activated para-aramid.

[0085] Activated para-aramid fibers were prepared using the same method as in Example 1, except that the amount of sulfosuccinate wetting and penetrating agent added was reduced in Comparative Example 5.

[0086] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.05 parts of OT-75 and 93.95 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0087] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0088] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0089] Comparative Example 6: Preparation of activated para-aramid.

[0090] Activated para-aramid was prepared using the same method as in Example 1, except that the mass ratio of epoxy resin to softener in Comparative Example 6 was 1:2 (not within the range of 1:(0.5-1.5) as defined in this invention).

[0091] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 91.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0092] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 4 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0093] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0094] Comparative Example 7: Preparation of activated para-aramid.

[0095] Activated para-aramid was prepared using the same method as in Example 1, except that the mass ratio of epoxy resin to softener in Comparative Example 6 was 1:0.2 (not within the range of 1:(0.5-1.5) as defined in this invention).

[0096] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 5 parts of E51, 0.2 parts of OT-75 and 91.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0097] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 1 part of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0098] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0099] Comparative Example 8: Preparation of activated para-aramid.

[0100] Activated para-aramid was prepared using the same method as in Example 1, except that the total mass ratio of the smoothing agent and the softener to the epoxy resin in Comparative Example 8 was 1:1 (not within the range of (1.5-2.5):1 as defined in this invention).

[0101] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 3 parts of E51, 0.2 parts of OT-75 and 93.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0102] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 1.5 parts of trimethylolpropane trioleate and 1.5 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0103] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0104] Comparative Example 9: Preparation of activated para-aramid.

[0105] Activated para-aramid was prepared using the same method as in Example 1, except that the total mass ratio of the smoothing agent and the softener to the epoxy resin in Comparative Example 9 was 3:1 (not within the range of (1.5-2.5):1 as defined in this invention).

[0106] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 6 parts of E51, 0.2 parts of OT-75 and 91.8 parts of deionized water were stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0107] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 1 part of trimethylolpropane trioleate and 1 part of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0108] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 3% slower than that of the upper oil roller. Other process conditions are the same as in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0109] Comparative Example 10: Preparation of activated para-aramid.

[0110] Activated para-aramid fibers were prepared using the same method as in Example 1, except that the upper and lower oil rollers in Comparative Example 10 had the same frequency.

[0111] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 93.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0112] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0113] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fiber is fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is the same as that of the upper oil roller. The starting speed of the oiling machine is the same as that in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0114] Comparative Example 11: Preparation of activated para-aramid.

[0115] Activated para-aramid fibers were prepared using the same method as in Example 1, except that the frequency of the lower oil roller in Comparative Example 11 was 6% slower than that of the upper oil roller (i.e., the frequency difference between the upper and lower oil rollers was greater than the range defined in this invention).

[0116] The specific preparation method is as follows: (1) Preparation of solubilizing epoxy activating oil: According to the weight parts, 2 parts of E51, 0.2 parts of OT-75 and 93.8 parts of deionized water are stirred at 50°C for 3 hours to obtain solubilizing epoxy activating oil.

[0117] (2) Preparation of activator: The obtained solubilized epoxy activator was cooled to 25°C, and 2 parts of trimethylolpropane trioleate and 2 parts of PEG 600 monostearate were added. The mixture was stirred at 30°C for 2 hours to obtain the activator.

[0118] (3) Preparation of low-cost activated para-aramid: The obtained activator is introduced into the upper oil tank, and the para-aramid fibers are fixed on the upper and lower oil rollers of the oiling machine. The frequency of the upper oil roller is set to 15Hz, and the frequency of the lower oil roller is 6% slower than that of the upper oil roller. The starting speed of the oiling machine is the same as that in Example 1. The machine is started to oil the para-aramid and activated para-aramid is obtained.

[0119] The activated para-aramid fibers prepared in the above embodiments and comparative examples were subjected to performance tests, and the test methods involved are as follows.

[0120] (1) Tensile strength test instructions: The activated para-aramid was tested on an electronic tensile testing machine manufactured by INSTRON in the UK according to the test method of GB / T 42823-2023. The maximum breaking force was tested, the tensile rate was 100 mm / min, and the median of 5 fibers in each group was taken.

[0121] (2) Friction coefficient test instructions: Refer to T / CNTAC 4-2017 "Test method for friction coefficient between yarn and solid material" and the winch method to determine the dynamic friction coefficient between activated para-aramid and stainless steel roller, which simulates the friction condition between yarn and metal guide during fiber twisting. The lower the friction coefficient value, the better the lubrication and smoothness effect of the fiber surface.

[0122] (3) Extraction Test Description: After twisting the activated fibers in all examples and comparative examples, a secondary treatment was performed using RFL. Then, natural styrene-butadiene rubber was used. According to GB / T2942-2009 "Determination of Static Adhesion Strength between Vulcanized Rubber and Fiber Cord - Extraction Method", the activated para-aramid fibers prepared in the above examples and comparative examples were twisted, and the adhesive samples were prepared and the adhesive performance was tested. The extraction test of the adhesive force between para-aramid and rubber was conducted on an electronic tensile testing machine manufactured by INSTRON in the UK according to GB / T2942-2009 standard. The test speed was 130 mm / min. The maximum force when the fiber was pulled out of the rubber was recorded. At least 10 samples were tested, and the average value of at least 10 valid data was recorded.

[0123] (4) Peel test instructions: The adhesive peel test is conducted on an electronic tensile testing machine in accordance with GB / T 40725-2021 standard. The test speed is 300 mm / min. The maximum force when the twisted active para-aramid fiber peels from the rubber at 180° is recorded. At least 6 samples are tested, and the average value of at least 6 valid data is recorded.

[0124] The twisted active para-aramid fibers used are: 1000D (fineness of a single twisted fiber); 1×3 (yarn structure); S / Z (twisting direction of primary / secondary twist); 225 / 130 (twisting degree of primary / secondary twist).

[0125] (5) Twisting condition test: The activated para-aramid was twisted for 8000m. The yarn structure was 1×3, the primary / secondary twist direction was S / Z, the primary twist degree was 335, the secondary twist degree was 190, and the fuzz condition was observed during the twisting process.

[0126] The specific test results are shown in Table 1 below.

[0127] Table 1 Performance Test Results

[0128] As can be seen from the data in Table 1 above, the activated para-aramid fibers prepared using the para-aramid activator and related preparation methods described in Examples 1-6 exhibit excellent performance in key indicators such as tensile strength, dynamic friction coefficient, H-pull-out force, 180° peel force, and twisting of the fibers. The appropriate ratio of epoxy resin to softener in the activator allows the long-chain ester structure of the softener to be embedded in the epoxy crosslinking network, playing a role in molecular spacing and plasticizing. This retains the active groups to ensure interfacial bonding while inhibiting excessive crosslinking of the epoxy. The surface hardness and brittleness caused by chemical treatment; the complementary division of labor between smoothing agents and softeners, where the former reduces dynamic friction between fibers and metal parts to ensure smooth passage through the guide opening, and the latter improves the flexibility of the fiber itself and forms a uniform and dense oil film to withstand bending without deformation; the matching of the total amount of functional components with epoxy resin ensures the continuity of the oil film without over-coating and shielding the activation sites; the appropriate use of sulfosuccinate penetrants achieves a balance between efficient emulsification and dispersion of oily components and maintaining oil film adhesion, making the oil agent stable and evenly spread. On this basis, the precise frequency difference of 2%~4% between the upper and lower rollers works synergistically with the above-mentioned high water and low oil activator system. The weak lateral rubbing generated by this frequency difference drives the surface oil to penetrate capillarily inward along the gaps between the monofilaments, so that the monofilaments inside the fiber bundle are fully activated without damaging the fiber structure due to excessive rubbing. This invention enables the simultaneous preparation of activated para-aramid products with low friction, high softness, anti-fuzzing, and high interfacial bonding strength even with extremely low effective ingredient content.

[0129] The comparison of the results of Comparative Example 1 and Example 1 shows that without the addition of smoothing and softening agents, epoxy resin and wetting penetrating agents alone cannot solve the problems of hard and brittle fiber surfaces and high coefficient of friction. During the twisting process, obvious fuzz and breakage of fibers occur, and the H-pulling force and peeling force are significantly reduced. This indicates that without the lubrication and softening protection of smoothing and softening agents, the fibers generate a large number of fuzz due to friction damage and bending fatigue during twisting. At the same time, the local excessive cross-linking and hardening of the fiber surface deteriorates the interfacial adhesion effect.

[0130] The comparison between the results of Comparative Example 2 and Example 1 shows that: if no softener is added, although the coefficient of dynamic friction is reduced, fuzz and breakage still occur during the twisting process, and the H pull-out force and peeling force are lower than those of Example 1. This indicates that although the smoother can reduce friction, it cannot improve the flexibility of the fiber body. The fiber is damaged due to internal stress concentration when it is bent and deformed. At the same time, the lack of molecular spacer effect of the softener and the excessively high epoxy crosslinking density lead to a hard and brittle surface, and the fuzz problem is not solved.

[0131] The comparison between the results of Comparative Example 3 and Example 1 shows that: without the addition of a smoothing agent, although the softening agent can improve flexibility and form an oil film, the dynamic friction coefficient is still too high. Filament breakage occurs during the twisting process, indicating that without the lubricating effect of the smoothing agent, the frictional resistance between the fiber and the metal guide is too large, and the oil film on the fiber surface is destroyed under high-speed friction. Although the softening agent can soften the fiber, it cannot replace the friction-reducing function of the smoothing agent. The two must work together to completely suppress filaments.

[0132] The comparison between the results of Comparative Example 4 and Example 1 shows that if the amount of sulfosuccinate wetting penetrant added is increased, the interfacial tension of the oil is excessively reduced, the adhesion of the oil film on the fiber surface decreases, and the H-extraction force and peeling force are significantly reduced. This indicates that more penetrant is not necessarily better. Although excessive penetrant can enhance the emulsification effect, it will weaken the bonding strength between the oil film and the fiber, thereby affecting the subsequent interfacial bonding performance with the rubber matrix.

[0133] The comparison between Comparative Example 5 and Example 1 shows that if the amount of succinate-based wetting and penetrating agent added is reduced, the epoxy resin cannot be fully emulsified and dispersed in the high-water system. The oil agent has poor stability and uneven oiling. Some areas of the fiber surface lack effective oil film protection, the dynamic friction coefficient increases and fuzz breakage occurs. This indicates that when the penetrating agent is insufficient, the oily components agglomerate and stratify in the aqueous phase, directly destroying the uniform spreading of the subsequent smoothing agent and softener, and the synergistic relationship between the three is broken.

[0134] The comparison of the results of Comparative Examples 6, 7 and 1 shows that: in the ratio of epoxy resin to softener, too much softener will over-coat the fiber surface and dilute the density of epoxy active groups, resulting in a decrease in H pull-out force and peel force; too little softener will not effectively inhibit excessive cross-linking and curing of epoxy, resulting in a hard and brittle fiber surface, an increased coefficient of dynamic friction and fuzz breakage. Therefore, controlling the ratio of epoxy resin to softener within a suitable range is more conducive to balancing activation activity and softening performance.

[0135] A comparison of the results from Comparative Examples 8, 9, and 1 shows that when the total amount of smoothing agent and softener relative to the epoxy resin is insufficient, the oil film is discontinuous, the fibers lack local protection, and fuzz appears during the twisting process. When the total amount of smoothing agent and softener is excessive, it overly covers the fiber surface, shields the epoxy activation sites, and significantly reduces the interfacial bonding strength. Controlling the ratio of the total amount of smoothing agent and softener to the epoxy resin within the verified range is more conducive to achieving a combined improvement in high activation activity and excellent processing performance.

[0136] A comparison of the results from Comparative Examples 10, 11, and 1 shows that the frequency difference between the upper and lower rollers plays a crucial role in achieving uniform penetration of the high-water, low-oil activator. Without a frequency difference, the activator can only adhere to the surface of the fiber bundle, and the internal monofilaments have weak interfacial adhesion due to lack of activation, resulting in a significant decrease in both H-pulling force and peeling force. When the frequency difference is too large, although the penetration problem is solved, the excessive twisting force damages the rigid molecular structure of the fiber, resulting in a significant decrease in tensile strength and H-pulling force, and causing fuzz breakage due to fiber damage. The 2%-4% frequency difference between the upper and lower oil rollers of this invention is more conducive to achieving a balance between penetration driving force and fiber structure protection effect.

[0137] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A para-aramid activation agent, characterized in that, The para-aramid activator comprises the following components in parts by weight: 2-5 parts epoxy resin; 0.1-0.4 parts of sulfosuccinate wetting and penetrating agent; 1-4 parts of smoothing agent; Fabric softener 1-4 parts; 80-100 parts deionized water.

2. The activation agent for poly-p-phenylene-terephthalamide according to claim 1, wherein The epoxy resin is at least one of E51, glycerol diglycidyl ether, and glycerol triglycidyl ether.

3. The activation agent for poly-p-phenylene-terephthalamide of claim 1, wherein, The sulfosuccinate wetting and penetrating agent is sodium diisooctyl sulfosuccinate.

4. The para-aramid activation agent of claim 1, wherein, The smoothing agent is at least one of trimethylolpropane trioleate, pentaerythritol tetraoleate, isooctyl stearate, and erucamide.

5. The para-aramid activation agent of claim 1, wherein, The softener is at least one of PEG 400 monooleate, PEG 600 monostearate, and glyceryl monostearate.

6. The para-aramid activation agent of claim 1, wherein, The mass ratio of the epoxy resin to the fabric softener is 1:(0.5-1.5). The mass ratio of the smoothing agent to the softening agent is 1:(0.5-2.0); The total mass ratio of the smoothing agent and the softening agent to the epoxy resin is (1.5-2.5):1; The mass ratio of the epoxy resin to the sulfosuccinate wetting and penetrating agent is 1:(0.05-0.12).

7. An activated para-aramid fiber, comprising para-aramid fibers and an oil film adhering to the surface of the para-aramid fibers, characterized in that, The oil film is formed by applying the para-aramid activator according to any one of claims 1-6.

8. The activated para-aramid fiber of claim 7, wherein, The oiling rate of the activated para-aramid is 5.6%-6.4%.

9. A method for preparing an activated para-aramid according to any one of claims 7-8, characterized in that, The preparation method is as follows: The para-aramid activator is introduced into the upper oil tank; Para-aramid fibers are fixed on the upper and lower oil rollers of an oiling machine, and the machine is started to apply oil to obtain activated para-aramid fibers. A frequency difference is provided between the upper and lower oil rollers.

10. The method for preparing activated para-aramid according to claim 9, characterized in that, The frequency of the upper oil roller is 5-20Hz, and the frequency of the lower oil roller is 2%-4% slower than that of the upper oil roller.

Images