An environment-friendly POY oil special for polyester fibers and a preparation method thereof

Abstract

This application relates to the field of textile auxiliary technology, and provides an environmentally friendly POY oil agent specifically for polyester fibers and its preparation method. The POY oil agent, by weight, comprises: a main lubricant: 44-52 parts, a migration inhibitor: 6-9 parts, an antistatic agent: 3-6 parts, a bundling precursor: 2.5-4.5 parts, a stabilizer: 3-6 parts, a pH adjuster: 0.5-1.2 parts, and deionized water: the balance, to a total of 100 parts. The bundling precursor includes fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:(0.6-1.2). This application, by first positioning the fatty acid precursor and then adding the organic amine, generates the bundling agent in situ, rather than directly adding a pre-made bundling agent. This effectively controls the timing and location of bundling, avoiding premature bundling that could affect the uniformity of the oil film and the stability of the fiber bundle.

Description

Technical Field

[0001] This application relates to the field of textile auxiliaries technology, and in particular to an environmentally friendly POY oil agent for polyester fibers and its preparation method. Background Technology

[0003] Polyester terephthalate (PET) fiber is widely used in textiles, clothing, industrial fabrics, and many other fields due to its excellent physical and chemical properties. With increasing environmental awareness and requirements for energy conservation and emission reduction in production processes, lubricants (such as POY oil) in the polyester fiber production process are gradually becoming an important direction for both environmental protection and performance requirements.

[0004] Traditional polyester POY lubricants are mainly used in the stretching, spinning, and tow lubrication of polyester fibers to reduce friction, improve tensile properties, and enhance production processes. However, some chemical components commonly used in traditional POY lubricants (such as petroleum-based lubricants and surfactants) are not only difficult to degrade and cause significant environmental pollution, but also easily have an adverse effect on fiber quality. Therefore, developing an environmentally friendly, high-performance POY lubricant, especially one that incorporates environmentally friendly biodegradable components, has become a significant technical challenge in polyester production.

[0005] The main function of polyester POY lubricants is to lubricate the fiber surface, reduce friction and wear during production, and ensure the smoothness and toughness of the fibers. Currently, most polyester POY lubricants on the market use traditional mineral oils and synthetic esters, but these ingredients often fail to meet the dual requirements of environmental protection, sustainability, and high performance in modern production.

[0006] Therefore, existing technologies still need to further explore environmentally friendly POY oils specifically for polyester fibers and their preparation methods to meet the demand. Summary of the Invention

[0007] In view of the above-mentioned shortcomings in the prior art, the purpose of this application is to provide an environmentally friendly POY oil agent for polyester fibers and its preparation method.

[0008] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, embodiments of this application provide an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: main lubricant: 44-52 parts, migration inhibitor: 6-9 parts, antistatic agent: 3-6 parts, bundle precursor: 2.5-4.5 parts, stabilizer: 3-6 parts, pH adjuster: 0.5-1.2 parts, deionized water: balance, to a total of 100 parts; wherein, the bundle precursor comprises fatty acids and organic amines, and the molar ratio of fatty acids to organic amines is 1:(0.6-1.2).

[0009] In an alternative embodiment, the migration barrier includes at least one or a combination of terephthalic acid fatty acid esters, isophthalic acid fatty acid esters, bisphenol low-residue esters, and aromatic ring-containing polyether esters; and / or the main lubricant includes linear fatty acid esters and branched polyol esters; and / or the antistatic agent includes at least one or a combination of alkyl phosphate potassium salts, fatty alcohol polyoxyethylene ether phosphate salts, alkyl sulfonates, and cocamidopropyl betaine; and / or the stabilizer includes at least one or a combination of isotridecyl alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, sorbitan fatty acid esters, fatty acid monoglycerides, and low EO number fatty alcohol ethers.

[0010] In an optional embodiment, the POY oil further comprises, by weight, 0.5-1.2 parts of an interfacial wetting agent, wherein the interfacial wetting agent comprises at least one of polyether, polyether ester and polyether carbonate.

[0011] Secondly, embodiments of this application provide a method for preparing an environmentally friendly POY oil agent specifically for polyester fibers, comprising the following steps: S100. The main lubricant and migration barrier are mixed and stirred, and fatty acids are added during the first stirring process to obtain the first composite functional liquid. S200: Mix antistatic agent, stabilizer and part of deionized water to obtain the second composite functional liquid; S300: Mix the first composite functional liquid and the second composite functional liquid and perform a second stirring treatment to obtain intermediate I; S400. Add organic amine to the intermediate, then add the remaining deionized water, and perform aging treatment to obtain POY oil. The molar ratio of fatty acids to organic amines is 1:(0.6-1.2).

[0012] In an optional implementation, S400 includes: S410. Prepare an organic amine solution by adding the organic amine solution dropwise to the intermediate to obtain intermediate II; S420. Divide the remaining deionized water into three parts, and add the first part of deionized water, the second part of deionized water and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is subjected to aging and filtration treatments in sequence to obtain POY oil.

[0013] In one optional embodiment, the mass concentration of the organic amine solution is 10-40%; and / or the dropping time of the organic amine solution is 10-60 min; and / or the pH is 6.5-8.5 after the organic amine solution is added; and / or the mass ratio of the first part of deionized water, the second part of deionized water and the third part of deionized water is 1:(0.3-1.2):(0.5-1.6).

[0014] In one alternative implementation, the curing process is carried out at a temperature of 25-35°C for 8-16 hours; and / or the filtration process uses an 80-200 mesh sieve.

[0015] In an optional embodiment, S200 further includes: adding an interface wetting agent and stirring at 25-45°C for 20-30 minutes.

[0016] In an optional embodiment, in S100, the temperature of the first stirring treatment is 45-50°C; and / or the time of the first stirring treatment is 30-70 min.

[0017] In an optional embodiment, in S300, the speed of the second stirring process is 300-1000 rpm; and / or the temperature of the second stirring process is 40-45°C; and / or the time of the second stirring process is 10-40 min.

[0018] The beneficial effects of this application include at least the following: (1) This application first locates the fatty acid precursor and then adds organic amine to generate a bundle in situ, instead of directly adding a pre-made bundle, which effectively controls the timing and position of the bundle and avoids premature bundle formation affecting the uniformity of the oil film and the stability of the bundle; (2) This application introduces a migration barrier to improve the thermal stability of the oil and reduce the migration and deposition of low molecular weight lubricating components at high temperatures, thereby reducing hot plate deposition, splashing and white powder generation, forming a low-adhesion, easy-to-wipe oil film, effectively solving the problem of hard coke deposits that are difficult to clean when traditional oils are formed at high temperatures. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are only for explaining this application, but the implementation of this application is not limited thereto.

[0020] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this application pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; the amounts of experimental reagents used are, unless otherwise specified, the amounts used in conventional experimental operations; and the experimental methods used are, unless otherwise specified, conventional methods.

[0021] With the increasing demand for PET fibers in textiles, apparel, and industrial applications, improving production efficiency and reducing environmental impact have become core issues for the industry. In traditional polyester production, POY lubricants, as indispensable lubricants in the spinning process, not only reduce friction and improve tensile properties but also significantly impact the stability of the production process. However, most existing POY lubricants rely on petroleum-based lubricants and synthetic ester additives. These components not only cause significant environmental pollution but also tend to migrate and volatilize at high temperatures, leading to equipment contamination, heat residue problems, and affecting fiber quality.

[0022] In view of this, this application provides an environmentally friendly POY oil specifically for polyester fibers and its preparation method. By first positioning the fatty acid precursor and then adding an organic amine in situ to generate a bundler, rather than directly adding a pre-made bundler, the timing and location of the bundle formation are effectively controlled, avoiding premature bundle formation that could affect the uniformity of the oil film and the stability of the fiber bundle. Furthermore, this application introduces a migration inhibitor to improve the thermal stability of the oil and reduce the migration and deposition of low-molecular-weight lubricating components at high temperatures. This reduces hot plate deposition, splashing, and white powder generation, forming a low-adhesion, easily wipeable oil film, effectively solving the problem of hard, coke-like deposits that are difficult to clean when traditional oils are used at high temperatures.

[0023] In a first aspect, embodiments of this application provide an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: main lubricant: 44-52 parts, migration inhibitor: 6-9 parts, antistatic agent: 3-6 parts, bundle precursor: 2.5-4.5 parts, stabilizer: 3-6 parts, pH adjuster: 0.5-1.2 parts, deionized water: balance, to a total of 100 parts; wherein, the bundle precursor comprises fatty acids and organic amines, and the molar ratio of fatty acids to organic amines is 1:(0.6-1.2).

[0024] Specifically, the main lubricant forms the basic framework of the oil film, providing basic smoothness and enabling the oil to form a continuous oil film on the polyester fiber surface. This is fundamental to ensuring the stability of high-speed spinning and winding of POY. The main lubricant includes linear fatty acid esters and branched polyol esters. The linear fatty acid ester molecular chains are relatively flexible and have good spreadability, which can quickly wet the PET fiber surface and form a low-friction boundary lubrication layer between the fiber and the guide and winding components. The branched polyol esters have a more three-dimensional molecular structure and lower volatility, which can improve the thickness stability and heat retention of the oil film. The mass ratio of linear fatty acid esters to branched polyol esters is (1.2-2.8):1, with linear fatty acid esters having a slight advantage to ensure rapid wetting and low friction on the fiber surface. At the same time, a sufficient amount of branched polyol esters is retained to improve the oil film strength, low volatility, and thermal stability. Migration inhibitors are further embedded in the oil film system, forming thermal migration hindrance regions within the main oil film. This reduces the migration, volatilization, and accumulation of low-molecular-weight lubricating components in high-temperature thermal contact areas, thereby reducing deposition, splashing, and white powder problems at hot rollers or hot boxes. Migration inhibitors include at least one or a combination of terephthalic acid fatty acid esters, isophthalic acid fatty acid esters, bisphenol low-residue esters, and aromatic ring-containing polyether esters. Their aromatic ring structures possess high thermal stability and strong molecular rigidity, making them less prone to volatilization or rapid migration at high temperatures. Furthermore, these types of migration inhibitors exhibit certain compatibility with the main lubricant at room temperature and can enter the main lubricating oil film. However, in the contact areas of hot rollers, hot boxes, or hot plates, their migration rate is lower than that of low-molecular-weight fatty acid ester lubricating components due to the influence of their molecular volume, polarity, and aromatic structure. Therefore, migration inhibitors can form thermal migration hindrance regions within the oil film, reducing the accumulation rate of low-molecular-weight lubricating components on the metal thermal contact surface, thus reducing splashing, white powder, and hot plate deposition at the source.

[0025] Preferably, the bundle precursor is used to generate some bundle components in situ from fatty acids and organic amines during the preparation process or after the system is formed. This avoids the bundler occupying the interface too early and improves the controllability of the timing and distribution of bundle formation. The bundle precursor includes fatty acids and organic amines. First, fatty acids such as decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid are distributed in the oily system formed by the main lubricant and migration barrier. Then, in subsequent steps, organic amines such as triethanolamine, diisopropanolamine, diethanolamine, N-methyldiethanolamine, and amino alcohol complexes are added to neutralize them in situ, generating fatty acid alcohol amine salts. This allows the bundler to be generated gradually, making the formation time and distribution of the bundle function more controllable. The fatty acid alcohol amine salts provide appropriate polarity and interfacial activity, which is beneficial for fiber cohesion and antistatic synergy. The incompletely neutralized fatty acids still have certain lubricity and weak association effects, which can prevent the system from being overly hydrophilic or overly bundled. The molar ratio of fatty acids to organic amines is 1:(0.6-1.2), which allows for control over the degree of in-situ neutralization, forming bundled micro-regions where fatty acids, fatty acid amine salts, and the main lubricating phase coexist. If the proportion of organic amines is too low, insufficient formation of fatty acid amine salts will result in insignificant bundling ability and antistatic synergistic effects. If the proportion of organic amines is too high, fatty acids may be over-neutralized, and the system will tend towards traditional finished fatty acid amine salt bundling agent systems, easily leading to excessive interfacial activity, local enrichment, or decreased oil film stability. The bundled micro-regions formed in this way ensure that the filament bundle is neither too loose nor too sticky, difficult to unwind, or experiences tension fluctuations due to excessive bundling.

[0026] Preferably, polyester fibers are hydrophobic and have poor electrical conductivity, making them prone to static electricity generation during high-speed spinning, friction, and winding. Therefore, antistatic agents need to be added. Antistatic agents primarily enhance the charge dissipation capacity of the oil film surface. The in-situ generated fatty acid amine salts also possess a certain polarity, which can assist in forming conductive channels. The fatty acid amine salts can synergistically work with the antistatic agent to reduce static electricity accumulation without significantly damaging the lubricating oil film, thereby reducing filament drift, roller entanglement, fuzz, and tension fluctuations during high-speed spinning, winding, and unwinding. Antistatic agents include at least one or a combination of alkyl phosphate potassium salts, fatty alcohol polyoxyethylene ether phosphate salts, alkyl sulfonates, and cocamidopropyl betaine. The anionic component in the antistatic agent can improve the ionic conductivity of the oil film surface; the amphoteric component can improve the system's adaptability to different pH and interfacial environments and enhance the stable distribution of the antistatic component on the oil film surface. More importantly, the in-situ generated fatty acid alcohol amine salts also have certain polarity and ionic characteristics, which can work synergistically with antistatic agents to form continuous or semi-continuous charge discharge channels on the fiber surface, thereby reducing static electricity accumulation and reducing frizz, fuzz, roller entanglement and winding instability.

[0027] Preferably, since multiple components coexist in this application, problems such as uneven emulsification, increased particle size, local agglomeration, or storage stratification are prone to occur. By adding stabilizers to stabilize the interface state, control the droplet size and distribution, and avoid coarse-particle agglomeration or storage stratification, coarse-particle agglomeration or storage stratification can be avoided. The stabilizers include at least one or a combination of isotridecyl alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, sorbitan fatty acid ester, fatty acid monoglyceride, and low EO number fatty alcohol ether. Among them, HLB nonionic emulsifiers such as isotridecyl alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and castor oil polyoxyethylene ether are beneficial to forming a stable oil-in-water dispersion system, and low HLB auxiliary emulsifiers such as sorbitan fatty acid ester, fatty acid monoglyceride, and low EO number fatty alcohol ether are beneficial to stabilizing the oil phase interior and oil-water interface.

[0028] Preferably, a pH adjuster is used to regulate the neutralization state of fatty acids and organic amines, inhibit ester hydrolysis, emulsion disruption, and pH drift of the system, thereby improving the storage stability of the oil and ensuring that in-situ bundling and antistatic synergy are in a suitable state. Preferred pH adjusters include citric acid, citrate, lactic acid, lactate, phosphate buffers, and weakly basic amine salt adjusters. Deionized water is used as the dispersion medium to form an emulsion system suitable for spinning, facilitating oiling, dilution, transport, and uniform coating.

[0029] Preferably, the surface of polyester PET fibers is relatively hydrophobic, and the contact time during high-speed spinning and winding is short. If the oil cannot spread quickly, problems such as localized oil deficiency, localized oil abundance, and discontinuous oil film can easily occur, thus affecting the coefficient of friction, fiber tension, and winding formation. Therefore, a small amount of interfacial wetting agent can help the oil reach and spread on the fiber surface more quickly, making the main lubricant, antistatic agent, and bundle precursor more evenly distributed. Therefore, the POY oil also includes, by weight, 0.5-1.2 parts of interfacial wetting agent to improve the initial spreading, dynamic wetting, and oiling uniformity of the oil on the surface of polyester POY fibers. Interfacial wetting agents include at least one of polyether, polyether ester and polyether carbonate. This is because the polyether segments have good hydrophilicity and flexibility, which helps to reduce the interfacial tension of the oil system and improve dynamic wetting ability. The ester group or carbonate structure can enhance its compatibility or adsorption tendency with the polyester PET surface, so that it can not only stay in the aqueous phase, but also participate in the spreading of the oil film on the fiber surface.

[0030] Preferably, during actual use, when applying oil, the main lubricating phase first spreads on the surface of the PET fibers to provide a low-friction oil film; the in-situ generated fatty acid alcohol amine salt microregions are distributed in the oil film or interface area to provide moderate cohesion, preventing the fiber bundle from becoming too loose; unneutralized fatty acids participate in lubrication and weak association, avoiding excessive hydrophilicity or viscosity of the oil film; the antistatic agent and fatty acid alcohol amine salt synergistically form charge discharge channels; and the migration inhibitor reduces the migration of low-molecular-weight lubricating components to the hot contact surface in the hot processing area.

[0031] Secondly, embodiments of this application provide a method for preparing an environmentally friendly POY oil agent specifically for polyester fibers, comprising the following steps: S100. The main lubricant and migration barrier are mixed and stirred, and fatty acids are added during the first stirring process to obtain the first composite functional liquid. S200: Mix antistatic agent, stabilizer and part of deionized water to obtain the second composite functional liquid; S300: Mix the first composite functional liquid and the second composite functional liquid and perform a second stirring treatment to obtain intermediate I; S400. Add organic amine to the intermediate, then add the remaining deionized water, and perform aging treatment to obtain POY oil. The molar ratio of fatty acids to organic amines is 1:(0.6-1.2).

[0032] Preferably, in step S100, the main lubricant and migration barrier are mixed, and fatty acids are added during stirring. The main lubricant is responsible for forming the basic lubricating oil film. The migration barrier is introduced into this oil film system in advance, which allows it to be better distributed inside the main oil film during subsequent oiling and hot processing, thereby reducing the migration and enrichment of low-molecular-weight lubricating components to the surface of the hot roller, hot box, or hot plate. If the migration barrier is added later, it is easy to have uneven distribution or only remain at local interfaces, making it difficult to fully exert the thermal migration blocking effect. Adding fatty acids during the stirring process is to allow the fatty acid precursor to be distributed in the oily system formed by the main lubricant and migration barrier. Fatty acids have a certain degree of lipophilicity and weak polarity. After entering the system first, they can form a pre-situted state inside the oil phase and near the future oil-water interface. This is beneficial for the subsequent addition of organic amines, so that the fatty acids will not be randomly distributed or locally concentrated, but will instead generate some fatty acid amine salt cluster components in situ in a relatively uniform oil film environment. The first stirring treatment is carried out at a temperature of 45-50℃ for 30-70 minutes to reduce the viscosity of the main lubricant system, improve the dispersion efficiency of migration inhibitors and fatty acids, and ensure that the main lubricant, migration inhibitors and fatty acids fully form a homogeneous oily functional system.

[0033] Preferably, in step S200, the antistatic agent, stabilizer, and a portion of deionized water are mixed. Antistatic agents generally function more readily in the aqueous phase or oil-water interface, while stabilizers are used to regulate the emulsion interface, control droplet formation, and improve dispersion stability. Mixing the antistatic agent and stabilizer with a portion of water beforehand allows them to form a more uniform dispersion, preventing localized aggregation, interfacial competition, or uneven emulsification after direct entry into the oil phase. In this step, the amount of deionized water is 10-25% of the total deionized water volume. If the amount of water is too small, the antistatic agent and stabilizer will be difficult to disperse sufficiently, leading to excessively high local concentrations when combined with the first composite functional liquid. If the amount of water is too large, the system will prematurely enter a highly diluted state, making the oil phase emulsification process difficult to control, and potentially disrupting the functional distribution of fatty acid precursors and migration inhibitors.

[0034] Furthermore, step S200 also includes: adding an interface wetting agent and stirring at 25-45°C for 20-30 minutes. The role of the interface wetting agent is to reduce the interfacial tension between the oil and the PET fiber surface, improve the initial wetting and dynamic spreading ability, so as to promote the dispersion of the interface wetting agent, antistatic agent and stabilizer, while avoiding excessive temperature leading to increased foam, changes in emulsifier structure or evaporation of aqueous phase, so as to fully mix the interfacial functional components, improve the spreading speed and oil film uniformity of POY fiber in the initial stage of oiling, and enable the main lubricant, antistatic agent and in-situ bundled micro-regions to be more evenly distributed on the fiber surface in the future.

[0035] Preferably, in step S300, mixing the first composite functional liquid and the second composite functional liquid and performing a second stirring treatment is to achieve controlled coupling between the oily functional system and the aqueous interface functional system. At this point, the system simultaneously contains the main lubrication region, the migration interception region, the fatty acid precursor pre-positioning region, and the antistatic-emulsification stabilization region, but the organic amine has not yet been added. Therefore, a large number of fatty acid amine salt cluster components have not yet been formed, which can avoid premature release of the clustering function and prevent local cohesion, flocculation, or coarse particle agglomeration in the early stage of emulsion formation. The second stirring treatment is performed at a speed of 300-1000 rpm, a temperature of 40-45℃, and a time of 10-40 min. This provides sufficient dispersing force while maintaining appropriate fluidity of the main lubrication system, allowing the first composite functional liquid to uniformly enter the second composite functional liquid to form intermediate I, providing a stable reaction environment for subsequent organic amine drop addition and in-situ partial neutralization.

[0036] Preferably, in step S400, an organic amine is added to intermediate I. At this point, fatty acids have already been pre-distributed in the first composite functional liquid and its mixture with the second composite functional liquid. Adding the organic amine allows for in-situ neutralization of the fatty acids and the organic amine in a predetermined dispersion environment, generating some fatty acid amine salts. Unlike traditional methods that directly add finished bundlers such as fatty acid triethanolamine salts or oleic acid triethanolamine salts, the bundler components in this method are generated in-situ after the system structure is formed. Therefore, the timing and distribution of the bundler function are more controllable. Adding residual deionized water is to further adjust the system's solid content, viscosity, and droplet distribution after the in-situ bundled micro-regions are formed, ensuring the oiling agent reaches a suitable state for spinning oiling, thereby reducing the risk of localized coarse agglomeration and giving the oiling agent better flowability, filterability, and oiling uniformity. The aging process is designed to further stabilize the droplet structure, clustered micro-regions, distribution of migration inhibitors, and interfacial distribution of antistatic components in the system. Immediately after neutralization and water replenishment, there may still be local concentration differences, droplet rearrangement, and unbalanced interfacial adsorption within the system. The aging process can stabilize the functional micro-regions, reducing storage stratification, particle size growth, and usage fluctuations.

[0037] Furthermore, the S400 includes: S410. Prepare an organic amine solution by adding the organic amine solution dropwise to the intermediate to obtain intermediate II; S420. Divide the remaining deionized water into three parts, and add the first part of deionized water, the second part of deionized water and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is subjected to aging and filtration treatments in sequence to obtain POY oil.

[0038] Preferably, in step S410, the organic amine is first prepared into an organic amine solution and then added dropwise to intermediate I. This is to control the contact rate and reaction location between the organic amine and fatty acids. When the organic amine solution is added dropwise at this time, the organic amine will gradually enter the fatty acid-containing micro-region from the aqueous phase or interface region, and neutralize the fatty acid in situ, generating some fatty acid amine salts. This avoids excessively high local concentrations of organic amine, which could lead to instantaneous large-scale salt formation, local flocculation, or coarse-sized particle aggregation, allowing the bundled components to be generated in a more dispersed manner. The organic amine solution is added dropwise at this time. On the one hand, the generation time of the bundled components is after the intermediate system is formed, avoiding the premature occupation of the interface by traditional finished bundlers. On the other hand, the fatty acid amine salts are gradually generated in the pre-positioned region of fatty acids, and their distribution is closer to the location where the oil film and emulsion droplets need to be bundled, thus facilitating the formation of uniform and flexible bundled micro-regions. The organic amine solution has a mass concentration of 10-40%. If the organic amine concentration is too low, the system will be introduced with too much water after addition, which can easily dilute the intermediate prematurely, making the emulsion structure unstable, reducing the contact efficiency between fatty acids and organic amines, and resulting in insufficient neutralization reaction and inadequate formation of clustered microregions. If the organic amine concentration is too high, the local alkalinity will be too strong after being added to the intermediate, which can easily lead to the instantaneous formation of more fatty acid amine salts in local areas, causing local salt formation, local thickening, coarsening of particle size, or even flocculation, which is not conducive to the formation of uniform clustered microregions. When the organic amine solution is added dropwise, the organic amine can gradually enter the intermediate system and gradually diffuse into the oil phase / interface microregion where fatty acids are located, and undergo in-situ partial neutralization with fatty acids. The fatty acid amine salts generated in this way are more easily dispersed at the emulsion droplet interface or near the oil film microregion, forming small, uniform, and moderately clustered microregions. This prevents the clustering function from being released prematurely, too strongly, or locally, and improves the oiling uniformity, tow width stability, winding tension stability, and subsequent unwinding performance. If the organic amine is added too quickly, it's equivalent to adding it all at once, which can easily cause a sudden increase in local pH, leading to rapid salt formation of fatty acids in certain areas, resulting in coarse clusters or local flocculation. If the addition time is too long, although the reaction is milder, the preparation efficiency decreases, and the system remains in an incompletely balanced state for an extended period, potentially causing emulsion structure fluctuations, fatty acid migration, or interfacial redistribution, which is detrimental to stability. Therefore, the optimal addition time for the organic amine solution is 10-60 minutes. After adding the organic amine solution, the pH is 6.5-8.5, allowing the POY oil to provide moderate clustering and antistatic synergy while maintaining the flexibility and low friction properties of the lubricating oil film.

[0039] Preferably, in step S420, if a large amount of water is added at once, the polarity of the system will change suddenly, which can easily cause local demulsification, coarsening of particle size, aggregation of clustered micro-regions, or uneven distribution of the oil phase. Adding the remaining three parts of deionized water in sequence allows the system to gradually transition from a higher viscosity state to the viscosity of the finished product, giving the droplets and functional micro-regions time to redistribute and stabilize. The first part of water is mainly used to initially reduce the viscosity of intermediate II, so that the in-situ generated fatty acid amine salt micro-regions can be further dispersed. After the first part of water addition, the viscosity of the system is 800-1500 mPa·s. The second part of water is used to further adjust the droplet spacing and interfacial stability. After the second part of water addition, the viscosity of the system is 200-600 mPa·s. The third part of water is used to make up the final water volume, so that the system reaches a viscosity and solid content suitable for POY oiling. After the third part of water addition, the viscosity of the system is 50-300 mPa·s. The mass ratio of the first, second, and third portions of deionized water is 1:(0.3-1.2):(0.5-1.6), which allows the system to smoothly transition from a higher viscosity state to the finished product state.

[0040] Preferably, in step S430, a curing and filtration process is performed to further stabilize the in-situ generated clustered micro-regions, the distribution of migration-blocking agents, the interface distribution of antistatic agents, and the emulsion structure. The curing process gradually brings the system to equilibrium, making the oil agent's performance more stable. The curing temperature is 25-35℃, and the time is 8-16 hours, allowing for curing under relatively mild conditions, which further stabilizes the clustered micro-regions, antistatic channels, and the distribution of migration-blocking agents, improving the storage stability, batch consistency, and oiling reliability of the finished product. The filtration process removes any small amounts of coarse particles or mechanical impurities, ensuring that the oil agent does not clog pipelines, cause localized oil spots, or result in uneven oiling during the spinning process. An 80-200 mesh sieve is used for filtration to reduce clogging and localized oiling defects, improving the stability of the oil agent in use.

[0041] Example 1

[0042] This embodiment provides an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: main lubricant: 44 parts, terephthalic acid fatty acid ester: 6 parts, alkyl phosphate potassium salt: 3 parts, bundle precursor: 2.5 parts, isomeric tridecyl alcohol polyoxyethylene ether: 3 parts, pH adjuster: 0.5 parts, deionized water: balance, to a total of 100 parts; wherein, the bundle precursor comprises fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:0.6, and the main lubricant comprises linear fatty acid esters and branched polyol esters, with a mass ratio of linear fatty acid esters to branched polyol esters of 1.2:1; Its preparation method includes the following steps: S100. Mix the main lubricant and terephthalic acid fatty acid ester and stir at 45°C for 30 minutes. Add fatty acids during the first stirring process to obtain the first composite functional liquid. S200. Mix potassium alkyl phosphate, isotridecyl alcohol polyoxyethylene ether, and 10% of the total amount of deionized water to obtain the second composite functional liquid. S300. Mix the first composite functional liquid with the second composite functional liquid and perform a second stirring treatment at 300 rpm and 40°C for 10 min to obtain intermediate I. S410. Prepare an organic amine solution with a concentration of 10%, and add the organic amine solution dropwise to the intermediate over a period of 10 minutes to obtain intermediate II; S420. Divide the remaining deionized water into three parts. The mass ratio of the first part, the second part, and the third part of deionized water is 1:0.3:0.5. Add the first part, the second part, and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is aged at 25°C for 8 hours, and then filtered through an 80-mesh sieve to obtain POY oil.

[0043] Example 2

[0044] This embodiment provides an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: main lubricant: 52 parts, isophthalic acid fatty acid ester: 9 parts, fatty alcohol polyoxyethylene ether phosphate salt: 6 parts, bundle precursor: 4.5 parts, fatty alcohol polyoxyethylene ether: 6 parts, polyether: 0.5 parts, pH adjuster: 1.2 parts, deionized water: balance, to a total of 100 parts; wherein, the bundle precursor includes fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:1.2, and the main lubricant includes linear fatty acid esters and branched polyol esters, with a mass ratio of linear fatty acid esters to branched polyol esters of 2.8:1; Its preparation method includes the following steps: S100. Mix the main lubricant and isophthalic acid fatty acid ester and stir at 50°C for 70 min. Add fatty acids during the first stirring process to obtain the first composite functional liquid. S200. Mix fatty alcohol polyoxyethylene ether phosphate salt, fatty alcohol polyoxyethylene ether and 25% deionized water, then add polyether and stir at 25°C for 20 minutes to obtain the second composite functional liquid. S300. The first composite functional liquid and the second composite functional liquid are mixed and subjected to a second stirring treatment at 1000 rpm and 45°C for 40 min to obtain intermediate I. S410. Prepare an organic amine solution with a concentration of 40%, and add the organic amine solution dropwise to the intermediate over a period of 60 minutes to obtain intermediate II; S420. Divide the remaining deionized water into three parts. The mass ratio of the first part, the second part, and the third part of deionized water is 1:1.2:1.6. Add the first part, the second part, and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is aged at 35°C for 16 hours, and then filtered through a 200-mesh sieve to obtain POY oil.

[0045] Example 3

[0046] This embodiment provides an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: 50 parts of main lubricant, 7 parts of aromatic ring-containing polyether ester, 5 parts of alkyl sulfonate, 3.5 parts of bundle precursor, 5 parts of castor oil polyoxyethylene ether, 1 part of pH adjuster, and deionized water to make up to 100 parts; wherein, the bundle precursor includes fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:0.8, and the main lubricant includes linear fatty acid esters and branched polyol esters, with a mass ratio of linear fatty acid esters to branched polyol esters of 2:1; Its preparation method includes the following steps: S100. The main lubricant and the polyether ester containing aromatic rings are mixed and stirred at 47°C for 60 min. Fatty acid is added during the first stirring process to obtain the first composite functional liquid. S200. Alkyl sulfonate, castor oil polyoxyethylene ether, and 20% of the total amount of deionized water are mixed to obtain the second composite functional liquid. S300. The first composite functional liquid and the second composite functional liquid are mixed and subjected to a second stirring treatment at 800 rpm and 42°C for 30 min to obtain intermediate I. S410. Prepare an organic amine solution with a concentration of 35%, and add the organic amine solution dropwise to the intermediate over a period of 10 minutes to obtain intermediate II; S420. Divide the remaining deionized water into three parts. The mass ratio of the first part of deionized water, the second part of deionized water and the third part of deionized water is 1:1:1. Add the first part of deionized water, the second part of deionized water and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is aged at 35°C for 12 hours, and then filtered through a 100-mesh sieve to obtain POY oil.

[0047] Example 4

[0048] This embodiment provides an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: 50 parts of main lubricant, 8 parts of terephthalic acid fatty acid ester, 4 parts of cocamidopropyl betaine, 4 parts of bundle precursor, 4 parts of dehydrated sorbitan fatty acid ester, 0.8 parts of polyether ester, 0.8 parts of pH adjuster, and the balance of deionized water, to a total of 100 parts; wherein, the bundle precursor comprises fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:0.7, and the main lubricant comprises linear fatty acid esters and branched polyol esters, with a mass ratio of linear fatty acid esters to branched polyol esters of 2:1; Its preparation method includes the following steps: S100. Mix the main lubricant and terephthalic acid fatty acid ester and stir at 47°C for 55 min. Add fatty acids during the first stirring process to obtain the first composite functional liquid. S200. Mix cocamidopropyl betaine, dehydrated sorbitan fatty acid ester and 25% deionized water, then add polyether ester and stir at 35°C for 30 min to obtain the second composite functional liquid. S300. The first composite functional liquid and the second composite functional liquid are mixed and subjected to a second stirring treatment at 900 rpm and 42°C for 30 min to obtain intermediate I. S410. Prepare an organic amine solution with a concentration of 35%, and add the organic amine solution dropwise to the intermediate over a period of 45 minutes to obtain intermediate II; S420. Divide the remaining deionized water into three parts. The mass ratio of the first part, the second part, and the third part of deionized water is 1:0.9:1.2. Add the first part, the second part, and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is aged at 30°C for 15 hours, and then filtered through a 180-mesh sieve to obtain POY oil.

[0049] Example 5

[0050] This embodiment provides an environmentally friendly POY oil agent specifically for polyester fibers, comprising, by weight: main lubricant: 48 parts, terephthalic acid fatty acid ester: 7.5 parts, cocamidopropyl betaine: 4.5 parts, bundle precursor: 3.5 parts, dehydrated sorbitan fatty acid ester: 5 parts, polyether ester: 0.8 parts, pH adjuster: 0.8 parts, deionized water: balance, to a total of 100 parts; wherein, the bundle precursor comprises fatty acids and organic amines, with a molar ratio of fatty acids to organic amines of 1:0.9, and the main lubricant comprises linear fatty acid esters and branched polyol esters, with a mass ratio of linear fatty acid esters to branched polyol esters of 2:1; Its preparation method includes the following steps: S100. Mix the main lubricant and terephthalic acid fatty acid ester and stir at 47°C for 55 min. Add fatty acids during the first stirring process to obtain the first composite functional liquid. S200. Mix cocamidopropyl betaine, dehydrated sorbitan fatty acid ester and 25% deionized water, then add polyether ester and stir at 35°C for 30 min to obtain the second composite functional liquid. S300. The first composite functional liquid and the second composite functional liquid are mixed and subjected to a second stirring treatment at 900 rpm and 42°C for 30 min to obtain intermediate I. S410. Prepare an organic amine solution with a concentration of 30%, and add the organic amine solution dropwise to the intermediate over a period of 40 minutes to obtain intermediate II; S420. Divide the remaining deionized water into three parts. The mass ratio of the first part, the second part, and the third part of deionized water is 1:0.9:1.2. Add the first part, the second part, and the third part of deionized water in sequence to obtain intermediate III. S430, intermediate III is aged at 30°C for 12 hours, and then filtered through a 150-mesh sieve to obtain POY oil.

[0051] Comparative Example 1 This comparative example provides a POY oil, which differs from Example 1 in that it does not have a clustering precursor and instead directly adds a clustering agent. In the preparation method, step S100 directly adds the clustering agent, and step S410 is omitted.

[0052] Comparative Example 2 This comparative example provides a POY oil, which differs from Example 1 in that it does not contain a migration inhibitor. In the preparation method, no migration inhibitor is added in step 100; only the main lubricant and fatty acid are uniformly mixed.

[0053] Comparative Example 3 This comparative example provides a POY oil, which differs from Example 1 in that the main lubricant is only a linear fatty acid ester.

[0054] Comparative Example 4 This comparative example provides a POY oil, which differs from Example 1 in that it does not contain an antistatic agent. In the preparation method, no antistatic agent is added in step S200.

[0055] Comparative Example 5 This comparative example provides a POY oil preparation, which differs from Example 1 in that it does not contain a bundled precursor, and in the preparation method, fatty acids are not added in step S100, and step S410 is omitted.

[0056] Comparative Example 6 This comparative example provides a POY oil, which differs from Example 1 in that all components are added at once and then directly stirred and emulsified.

[0057] Comparative Example 7 This comparative example provides a POY oil preparation, which differs from Example 1 in that, in the preparation method, fatty acids and organic amines are added simultaneously in step S100, and step S410 is omitted.

[0058] Comparative Example 8 This comparative example provides a POY oil, which differs from Example 1 in that, in the preparation method, the organic amine solution is not added dropwise in step S410, but is added all at once.

[0059] Comparative Example 9 This comparative example provides a POY oil agent, which differs from Example 1 in that, in the preparation method, the remaining deionized water in step S420 is not divided into three parts, but is directly added all the remaining deionized water at once.

[0060] Comparative Example 10 This comparative example provides a POY oil agent, which differs from Example 1 in that it does not contain a migration barrier agent. In the preparation method, no migration barrier agent is added in step S100, and an anti-deposition agent is added directly.

[0061] Comparative Example 11 This comparative example provides a POY oil preparation, which differs from Example 1 in that the bundle precursor is only fatty acid, and step S410 is not included in the preparation method.

[0062] Comparative Example 12 This comparative example provides a POY oil preparation, which differs from Example 1 in that the bundle precursor is only an organic amine, and no fatty acids are added in step S100 of the preparation method.

[0063] Comparative Example 13 This comparative example provides a POY oil formulation, which differs from Example 1 in that the molar ratio of fatty acid to organic amine in the bundled precursor is 1:2.

[0064] This application has undergone multiple experiments, and some of the test results are presented here for reference to further describe the invention in detail. The following is a detailed description in conjunction with specific embodiments.

[0065] Performance testing Storage stability test: The POY oils in Examples 1-5 and Comparative Examples 1-13 were placed in transparent glass bottles and stored at 25°C for 30 days. The results were observed to see if stratification, precipitation, flocculation or obvious oil floating occurred. D90 particle size test: The D90 particle size of the POY oils in Examples 1-5 and Comparative Examples 1-13 was tested using a particle size analyzer. Viscosity test: The viscosity of the POY oils in Examples 1-5 and Comparative Examples 1-13 was tested at 25°C using a rotational viscometer. pH test: The pH of the POY oil in Examples 1-5 and Comparative Examples 1-13 was tested using a pH meter; Acid value test: Test the acid value I after adding fatty acids in step S100 and the acid value II after adding organic amines in step S410, and calculate the neutralization rate according to the following formula. Neutralization rate = (acid value I - acid value II) / acid value I × 100%; The test results are shown in Table 1.

[0066] Table 1 As can be seen from Table 1, Examples 1-5 all exhibit good stability and can form stable emulsions, especially Example 5. This is because the proportions in Example 5 are appropriate and the process parameters are reasonably selected. The D90 particle size of Comparative Example 1 is relatively large, indicating that the finished product aggregate tends to occupy the interface prematurely, leading to emulsion coarsening. The D90 particle size of Comparative Examples 6-8 is also significantly increased, indicating that direct mixing, simultaneous addition of organic amines and fatty acids, and one-time addition of organic amines all lead to an increase in the particle size of the finished product, indicating that the preparation order and dropping method are very important for the formation of stable microregions. The neutralization rate, pH, D90 particle size, and viscosity of Comparative Example 13 are all relatively high, indicating that an inappropriate ratio of fatty acids and organic amines will cause the system to deviate from the partially neutralized state required by this scheme.

[0067] Wetting time test: Equal amounts of POY oil from Examples 1-5 and Comparative Examples 1-13 were dropped onto the surface of polyester POY filament sheet, and the time required for the droplets to spread to twice the initial area was recorded. Oiling uniformity test: The POY oiling agents in Examples 1-5 and Comparative Examples 1-13 were applied to polyester POY filaments at the same oiling rate. The oil content was measured at different locations, and the coefficient of variation of oil content CV was calculated. Friction coefficient test: The dynamic friction coefficient between the polyester POY filament bundles oiled with the POY oils in Examples 1-5 and Comparative Examples 1-13 and the metal guide was determined using a fiber friction coefficient tester. Bundling index test: The bundled index of polyester POY filaments oiled with the POY oiling agents in Examples 1-5 and Comparative Examples 1-13 was calculated. Electrostatic voltage and charge decay time test: Under standard temperature and humidity conditions, the POY filaments treated with the POY oil in Examples 1-5 and Comparative Examples 1-13 were rubbed with metal / ceramic guides, and the peak electrostatic voltage and charge decay time were tested. The test results are shown in Table 2.

[0068] Table 2 As shown in Table 2, Examples 1-5 are significantly better than the Comparative Examples in terms of wetting, oiling uniformity, friction coefficient, bundle index, electrostatic voltage, fuzziness, and breakage, especially Example 5. Although Comparative Example 1 has a better bundle index, its oiling uniformity, fuzziness, and breakage are increased, indicating that directly adding the finished bundle agent can easily cause local enrichment and uneven oil film. The bundle index of Comparative Example 5 is reduced, indicating that the bundle precursor is necessary for the cohesion and winding stability of the filament bundle. The bundle index of Comparative Example 11 is poor, indicating that fatty acids alone are insufficient to form effective bundle micro-regions. The pH of Comparative Example 12 is too high, and the wetting and oiling uniformity are worse, indicating that organic amines themselves cannot replace the in-situ neutralization structure of fatty acids and organic amines. Comparative Example 13 has strong bundles, but the fuzziness, breakage, and oiling uniformity are worse, indicating that excessive neutralization will lead to excessively strong filament cohesion, localized stickiness of the oil film, or excessive interfacial activity, which is not conducive to actual processing.

[0069] Quality retention rate test: The POY oils from Examples 1-5 and Comparative Examples 1-13 were heated at 250°C for 1 hour, and the mass change after heating was tested and the quality retention rate was calculated. Hot plate deposition test: The POY oil from Examples 1-5 and Comparative Examples 1-13 was coated on the surface of a stainless steel hot plate, heated at 250°C for 1 hour, and weighed after cooling. Splash point count test: POY oils from Examples 1-5 and Comparative Examples 1-13 were dropped onto a hot plate at 250°C, and the number of splash points within a specified area was counted. White powder content test: The POY oil in Examples 1-5 and Comparative Examples 1-13 was simulated using a DTY hot box, and the mass of white powder or thermally deposited powder generated per unit time was collected. Residual erasability test: After the hot plate deposition test is completed, a standard lint-free cloth is used to wipe the surface under a fixed pressure and a fixed number of times. The change in residual mass before and after wiping is calculated, and the erasability rate is calculated. The test results are shown in Table 3.

[0070] Table 3 As can be seen from Table 3, the performance of Examples 1-5 is good, especially Example 5, which can effectively form a heat-stable oil film with low migration, low adhesion, and easy cleaning. The mass retention rate at 250°C in Comparative Example 2 is poor, and the amount of hot plate deposition and the number of splash points are large, indicating that the migration barrier plays a key role in reducing high-temperature migration, splashing, and deposition. The mass retention rate at 250°C in Comparative Example 3 is poor, and the amount of hot plate deposition and the number of splash points are significantly increased, indicating that single linear fatty acid esters are prone to migration, volatilization, and splashing at high temperatures, indicating that it is necessary to combine linear fatty acid esters with branched polyol esters. The performance of Comparative Example 10 is inferior to that of Example 1, indicating that the migration barrier in this application is not a common anti-deposition agent, but rather works by reducing the migration of low-molecular-weight lubricating components to the thermal contact area. The residual wiping rate of Comparative Example 13 is poor, indicating that excessive organic amines lead to excessive salt formation, which may cause the system to form stronger adhesive residues or localized coking deposits, which is not conducive to thermal cleaning performance.

[0071] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An environmentally friendly POY oiling agent specifically for polyester fibers, characterized in that, By weight, it includes: Main lubricant: 44-52 parts, Migration inhibitor: 6-9 parts Antistatic agent: 3-6 parts Cluster precursor: 2.5-4.5 parts, Stabilizer: 3-6 parts pH adjuster: 0.5-1.2 parts, Deionized water: Remaining amount, bring to 100 parts; The bundle precursor comprises fatty acids and organic amines, wherein the molar ratio of the fatty acids to the organic amines is 1:(0.6-1.2).

2. The POY oiling agent according to claim 1, characterized in that, The migration blocking agent comprises at least one or a combination of terephthalic acid fatty acid esters, isophthalic acid fatty acid esters, bisphenol low-residue esters, and aromatic ring-containing polyether esters; and / or The bulk lubricant comprises linear fatty acid esters and branched polyol esters; and / or The antistatic agent comprises at least one or a combination of potassium alkyl phosphate, fatty alcohol polyoxyethylene ether phosphate, alkyl sulfonate, and cocamidopropyl betaine; and / or The stabilizer includes at least one or a combination of isotridecyl alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, castor oil polyoxyethylene ether, sorbitan fatty acid ester, fatty acid monoglyceride, and low EO fatty alcohol ether.

3. The POY oiling agent according to claim 1, characterized in that, The POY oil agent also includes, by weight: Interface wetting agent, 0.5-1.2 parts, The interface wetting agent includes at least one of polyether, polyether ester and polyether carbonate.

4. A method for preparing an environmentally friendly POY oiling agent specifically for polyester fibers, characterized in that, Includes the following steps: S100. The main lubricant and the migration barrier are mixed and stirred, and fatty acids are added during the first stirring process to obtain the first composite functional liquid. S200: Mix the antistatic agent, the stabilizer, and a portion of the deionized water to obtain a second composite functional liquid; S300: Mix the first composite functional liquid and the second composite functional liquid and perform a second stirring treatment to obtain intermediate I; S400. The organic amine is added to the intermediate, and the remaining deionized water is added to perform aging treatment to obtain the POY oil agent. The molar ratio of the fatty acid to the organic amine is 1:(0.6-1.2).

5. The preparation method according to claim 4, characterized in that, The S400 includes: S410. Prepare an organic amine solution from the organic amine, and add the organic amine solution dropwise to the intermediate to obtain intermediate II; S420. Divide the remaining deionized water into three parts, and add the first part of the deionized water, the second part of the deionized water and the third part of the deionized water in sequence to obtain intermediate III. S430. The intermediate III is subjected to the aging and filtration processes in sequence to obtain the POY oil.

6. The preparation method according to claim 5, characterized in that, The organic amine solution has a mass concentration of 10-40%; and / or The organic amine solution is added over a period of 10-60 minutes; and / or After adding the organic amine solution, the pH is 6.5-8.5; and / or The mass ratio of the first, second, and third portions of the deionized water is 1:(0.3-1.2):(0.5-1.6).

7. The preparation method according to claim 5, characterized in that, The ripening treatment is performed at a temperature of 25-35℃ for 8-16 hours; and / or The filtration process uses an 80-200 mesh screen.

8. The preparation method according to claim 4, characterized in that, S200 also includes: Add the interface wetting agent and stir at 25-45℃ for 20-30 minutes.

9. The preparation method according to claim 4, characterized in that, In S100, The temperature of the first stirring treatment is 45-50℃; and / or The first stirring treatment time is 30-70 minutes.

10. The preparation method according to claim 4, characterized in that, In S300, The second stirring process is carried out at a speed of 300-1000 rpm; and / or The temperature of the second stirring treatment is 40-45℃; and / or The second stirring treatment takes 10-40 minutes.

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