A method to improve the success rate of POY (Professional Development Year) tailing.

Abstract

This invention discloses a method for improving the success rate of POY yarn spinning. The method is characterized by the following steps: POY yarn cake is prepared through slurry preparation, esterification, polycondensation, metering, melt extrusion via spinneret, cooling, oiling, and winding. During POY spinning, the oil content of the initial 0-1000m length of the POY bottom yarn and the last 1000m length of the POY surface yarn in each POY yarn cake is increased by 8-15%, while the oil content of the middle portion of the POY yarn remains unchanged. This method solves the problem of high yarn breakage rates caused by reduced yarn cohesion and adhesion of the bottom yarn after the oil evaporates.

Description

Technical Field

[0001] This invention relates to the technical field of textile processes, and specifically to a method for improving the success rate of POY finishing. Background Technology

[0002] Polyester pre-oriented yarn, also known as partially oriented polyester yarn (POY), is a nascent yarn obtained through high-speed spinning (spinning speed 2800–3600 m / min). Compared to ordinary polyester drawn yarn, it has lower orientation and crystallinity, resulting in lower breaking strength, higher elongation at break, and poor dimensional stability in its physical properties. Therefore, it must undergo stretching, false twisting, and setting processes to produce textured yarn (DTY) with specific physical and mechanical properties to meet the requirements of subsequent weaving. The breakage rate during the POY-to-DTY processing directly affects the production efficiency and the yield of high-quality products in subsequent processing. Investigations show that over-tightening breaks account for over 70% of the breakage rate in POY processing. Over-tightening refers to the process where the tail of one POY bobbin meets the surface end of another POY bobbin during the continuous processing of pre-oriented polyester yarn into low-elasticity polyester yarn.

[0003] Many factors influence the texturing overrun rate, such as POY product quality, paper tube quality, equipment factors, and end quality. Under the premise that external factors such as equipment and paper tubes are functioning normally, improving the cohesion of the POY filament bundle is beneficial to increasing the DTY overrun rate. Therefore, patent CN 112746363 improves the cohesion of the filament bundle by setting network points in the POY bottom layer filaments, thereby reducing bottom layer overrun breakage. However, because there are network points within 6000 meters of the bottom layer filaments, stiff and tight points are easily generated during post-processing false twisting deformation, leading to quality problems such as hidden streaks on the fabric surface. At the same time, the biggest problem is that the oil in the bottom layer and surface filaments can evaporate, affecting the cohesion of the filament bundle and causing overrun breakage. Although increasing the oil content of the POY filament bundle can improve the cohesion of the filament bundle during post-processing, excessively high POY oil content can shorten the DTY hot box maintenance cycle, thus limiting the potential for increasing the upper limit of oil content in POY filaments. Meanwhile, the quality of the bottom and surface filaments of POY yarn plays a crucial role in the success rate of the finishing process. Currently, due to high POY inventory levels, after several months of storage, a significant amount of the surface filament oil has evaporated, reducing the cohesion of the filament bundle. Furthermore, after prolonged compression, approximately 90% of the water in the POY oil permeates into the paper tube. This water melts the curing adhesive used to bond the parchment paper to the paper tube surface, causing some bottom filaments to adhere to the adhesive. This adhesive then breaks the bottom filaments during the finishing process, affecting the finishing rate. Summary of the Invention

[0004] In order to solve one or more technical problems existing in the prior art, the purpose of this application is to provide a method to improve the success rate of POY tailing, which can solve the problem of high tailing breakage rate caused by reduced yarn cohesion and adhesion of bottom yarn after the oil evaporates.

[0005] To solve the aforementioned technical problems, this application adopts the following technical solution:

[0006] A method for improving the success rate of POY yarn spinning involves POY yarn cake being prepared by slurry preparation, esterification, polycondensation, metering, melt extrusion through a spinneret, cooling, oiling, and winding. During POY yarn spinning, the oil content of the bottom POY yarn in the initial length of 0-1000m and the top POY yarn in the last 1000m of each POY yarn cake is increased by 8-15%, while the oil content of the middle part of the POY yarn remains unchanged.

[0007] Preferably, the method for increasing the oil content of the surface 1000 meters and bottom 1000 meters of the silk cake includes:

[0008] Step 1: First, calculate the full roll time T1 of one yarn, T1 = roll weight * 10000 / specification * spinning speed;

[0009] Step 2: Calculate the time T2 required for 1000 meters of filament to undergo the oiling process, where T2 = 1000 meters / spinning speed;

[0010] Step 3: Set the oil output frequency of the oil pump in the oiling process to increase the oil content in the passing yarn bundle. The oil output frequency of the oil pump is increased by the following time: T2 of the bottom layer of the first yarn cake after re-heading, T1-T2 of the surface yarn of the first yarn cake, and T1+T2 of the bottom layer yarn of the second yarn.

[0011] Step 4: Based on the time T2 required for the oiling process, automatically control the oil pump to increase the oil output frequency, thereby increasing the oil content of the filament bundle passing through within T2 time, and thus increasing the oil content of the bottom 1000 meters of filament bundle in the first filament cake after re-heading.

[0012] Step 5: Calculate the time required to increase the oil pump frequency for the surface 1000 meters of the filament bundle in the first filament cake after re-starting the yarn and the time required to increase the oil pump frequency for the bottom 1000 meters of the filament bundle in the second filament cake based on the time T1-T2 to T1+T2. During the time T1-T2 to T1+T2, increase the frequency of the oil pump by automatic control to increase the oil for the surface 1000 meters of the filament bundle in the first filament cake and the bottom 1000 meters of the filament bundle in the second filament cake after re-starting the yarn.

[0013] Step 6: Based on the time intervals from 2*T1-T2 to 2*T1+T2, calculate the time required to increase the oil pump frequency for the surface 1000 meters of the filament bundle in the second filament cake after re-starting oil production, and the time required to increase the oil pump frequency for the bottom 1000 meters of the filament bundle in the third filament cake. During the time interval from 2*T1-T2 to 2*T1+T2, increase the frequency of the oil pump through automatic control to increase the oil production of the surface 1000 meters of the filament bundle in the second filament cake after re-starting oil production and the bottom 1000 meters of the filament bundle in the third filament cake.

[0014] Step 7: Calculate the time required to increase the oil pump frequency for the surface 1000 meters of the yarn bundle in the Nth yarn cake after regeneration, and the time required to increase the oil pump frequency for the bottom 1000 meters of the yarn bundle in the Nth yarn cake after regeneration, based on the calculation method from N*T1-T2 to N*T1+T2. Then, during the time period from N*T1-T2 to N*T1+T2, increase the frequency of the oil pump by automatic control to increase the oil for the surface 1000 meters of the yarn bundle in the Nth yarn cake after regeneration and the bottom 1000 meters of the yarn bundle in the Nth yarn cake.

[0015] Preferably, the method for handling the interruption that occurs during continuous production of the silk cake includes:

[0016] Step 1: The oil pump needs to be shut down and any related issues addressed.

[0017] Step 2: Restart the oil pump, and then recalculate the oil pump's oil output frequency increase time based on the oiling method for the surface 1000 meters and bottom 1000 meters of the filament bundles in the filament cake, and implement automatic control.

[0018] Preferably, the oil content of the POY bottom yarn in the first 0-1000m and the POY surface yarn in the last 1000m of each POY yarn cake is increased by 8-12%.

[0019] This invention increases the oil content of the initial 0-1000m POY bottom yarn and the last 1000m POY surface yarn by 8-12%. This ensures a high oil content in the bottom yarn even after the surface yarn evaporates and the bottom yarn paper tube absorbs oil, maintaining the yarn bundle cohesion and thus improving the finishing rate. Simultaneously, by automatically controlling the oil output through an oil pump with extended time, the oil output can be flexibly adjusted according to different varieties and required lengths of surface and bottom yarns, further enhancing the cohesion of the bottom and surface yarns and increasing the texturing finishing rate.

[0020] Preferably, the oil mixture in the oiling process includes crude oil, fluorocarbon surfactant, deionized water, and preservative, wherein the crude oil is diluted to form a mixed oil with an oil concentration of 8-15%.

[0021] Preferably, the content of the preservative is 0.5% to 1%.

[0022] Preferably, the carbon and fluorine content in the mixed oil mixture is 10.5 to 13.5 wt%.

[0023] Preferably, the mixed oil also contains a polyoxyethylene-type nonionic surfactant.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) For a yarn cake with an outer diameter of about 125mm, the oil content of the POY bottom yarn in the initial length of 0-1000m and the POY surface yarn in the last 1000m of the yarn cake is increased by 8-15%, while the middle area remains unchanged. 1000m is equivalent to about 255 turns of the paper tube to cover the bottom paper tube, which will not affect the oil content of the entire yarn cake. Even if the surface yarn of the yarn cake evaporates and the bottom yarn paper tube absorbs oil, the oil content of the bottom layer can still be guaranteed to be high, and the yarn bundle cohesion will not be reduced. The obtained texturing over-tail rate of the currently produced POY yarn is over 96%, and the texturing over-tail rate of POY yarn stored for three months is over 95.5%, thereby improving the over-tail rate.

[0026] (2) When the oil content of the bottom 1000 meters and the top 1000 meters of the present invention is increased, it will not affect the coking situation of the DTY texturing box. This will prevent the problem of reduced cohesion of the filament bundles due to the evaporation of the oil agent when the POY is over-tailed, thus ensuring the effect of low breakage at the end.

[0027] (3) The crude oil used in this invention contains fluorocarbon surfactants, which solves the problem that the bottom filament melts the glue on the paper tube, causing adhesion and leading to breakage at the end. Detailed Implementation

[0028] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0029] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicating orientation or positional relationship are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0031] A method for improving the success rate of POY yarn spinning includes POY yarn cakes, which are obtained by sizing, esterification, polycondensation, metering, melt extrusion through a spinneret, cooling, oiling, and winding. During POY spinning, the oil content of the initial 0-1000m length of the POY bottom yarn and the last 1000m length of the POY surface yarn in each POY yarn cake is increased by 8-15%, while the oil content of the middle portion of the POY yarn remains unchanged. The method for increasing the oil content of the surface yarn within 1000m and the bottom yarn within 1000m of the yarn cake includes:

[0032] Step 1: First, calculate the full roll time T1 of one yarn, T1 = roll weight * 10000 / specification * spinning speed;

[0033] Step 2: Calculate the time T2 required for 1000 meters of filament to undergo the oiling process, where T2 = 1000 meters / spinning speed;

[0034] Step 3: Set the oil output frequency of the oil pump in the oiling process to increase the oil content in the passing yarn bundle. The oil output frequency of the oil pump is increased by the following time: T2 of the bottom layer of the first yarn cake after re-heading, T1-T2 of the surface yarn of the first yarn cake, and T1+T2 of the bottom layer yarn of the second yarn.

[0035] Step 4: Based on the time T2 required for the oiling process, automatically control the oil pump to increase the oil output frequency, thereby increasing the oil content of the filament bundle passing through within T2 time, and thus increasing the oil content of the bottom 1000 meters of filament bundle in the first filament cake after re-heading.

[0036] Step 5: Calculate the time required to increase the oil pump frequency for the surface 1000 meters of the filament bundle in the first filament cake after re-starting the yarn and the time required to increase the oil pump frequency for the bottom 1000 meters of the filament bundle in the second filament cake based on the time T1-T2 to T1+T2. During the time T1-T2 to T1+T2, increase the frequency of the oil pump by automatic control to increase the oil for the surface 1000 meters of the filament bundle in the first filament cake and the bottom 1000 meters of the filament bundle in the second filament cake after re-starting the yarn.

[0037] Step 6: Based on the time intervals from 2*T1-T2 to 2*T1+T2, calculate the time required to increase the oil pump frequency for the surface 1000 meters of the filament bundle in the second filament cake after re-starting oil production, and the time required to increase the oil pump frequency for the bottom 1000 meters of the filament bundle in the third filament cake. During the time interval from 2*T1-T2 to 2*T1+T2, increase the frequency of the oil pump through automatic control to increase the oil production of the surface 1000 meters of the filament bundle in the second filament cake after re-starting oil production and the bottom 1000 meters of the filament bundle in the third filament cake.

[0038] Step 7: Calculate the time required to increase the oil pump frequency for the surface 1000 meters of the yarn bundle in the Nth yarn cake after regeneration, and the time required to increase the oil pump frequency for the bottom 1000 meters of the yarn bundle in the Nth yarn cake after regeneration, based on the calculation method from N*T1-T2 to N*T1+T2. Then, during the time period from N*T1-T2 to N*T1+T2, increase the frequency of the oil pump by automatic control to increase the oil for the surface 1000 meters of the yarn bundle in the Nth yarn cake after regeneration and the bottom 1000 meters of the yarn bundle in the Nth yarn cake.

[0039] In the production process of polyester pre-oriented yarn, a single 15.5kg polyester pre-oriented yarn is approximately one million meters long. During the continuous processing of polyester pre-oriented yarn into polyester low-elasticity yarn, when the tail yarn of one POY bobbin meets the surface yarn of another POY bobbin, the network points within the bottom 6000 meters can easily cause stiff and tight points during subsequent false twisting deformation, leading to quality problems such as hidden streaks on the fabric surface. Especially after the oil agent in the bottom and surface yarns of the yarn cake evaporates, it will affect the cohesion of the yarn bundle, resulting in the problem of end breakage. Although increasing the oil content of the POY yarn bundle can improve the cohesion of the yarn bundle in later processing, an excessively high oil content of POY can easily lead to a shorter maintenance cycle in the DTY hot box, thus limiting the possibility of increasing the upper limit of oil content in POY yarn. Therefore, to solve this problem, the oil content of the POY bottom layer yarn (0-1000m) and the POY surface yarn (last 1000m) of the yarn cake is increased by 8-15%, while the middle region remains unchanged. For a yarn cake with a paper tube outer diameter of about 125mm, 1000m is equivalent to about 255 turns of the paper tube to cover the bottom layer paper tube, which will not affect the overall oil content of the yarn cake. Even after the surface yarn evaporates and the bottom layer paper tube absorbs oil, the oil content of the bottom layer can still be kept high. The yarn bundle cohesion is not reduced, and the texturing finish rate of the obtained POY yarn is over 96%, while the texturing finish rate of POY yarn stored for three months is over 95.5%, thus improving the finish rate. Simultaneously, increasing the oil content only in the bottom 1000 meters and the top 1000 meters does not affect the coking situation in the DTY texturing hot box. This prevents the yarn bundle cohesion from decreasing after the oil evaporates during the POY finish process, ensuring a low breakage rate. Adding oil to the top 1000 meters of yarn bundle and the bottom 1000 meters of yarn bundle in each yarn cake is simple and convenient to control, and ensures that the finishing yarn bundle is oiled in each yarn cake.

[0040] A further improvement is made to the method for handling the interruption that occurs during continuous production of silk cakes, including:

[0041] Step 1: The oil pump needs to be shut down and any related issues addressed.

[0042] Step 2: Restart the oil pump, and then recalculate the oil pump's oil output frequency increase time based on the oiling method for the surface 1000 meters and bottom 1000 meters of the filament bundles in the filament cake, and implement automatic control.

[0043] Even if a sudden equipment failure occurs during the production of the silk cake, the system can continue to calculate the start-up time of the oil pump based on the system data. Moreover, when adding oil, it will only affect the length of the current silk cake to a certain extent, and will not affect the oiling of the beginning and end of the subsequent silk cakes.

[0044] A further improvement is made by increasing the oil content of the POY bottom yarn (0-1000m in the initial length) and the POY surface yarn (last 1000m) of each POY yarn cake by 8-12%.

[0045] Even after the surface yarn evaporates and the bottom yarn absorbs oil, the oil content of the bottom layer remains high, and the yarn cohesion is not reduced, thereby increasing the over-tail rate to 96.5%. The oil content is increased only in the surface and bottom layers of the POY yarn. Since a single 15.5kg polyester pre-oriented yarn is approximately millions of meters long, this will not affect the coking situation in the subsequent DTY texturing hot box. Specifically, increasing the oil content of the initial 0-1000m length of the POY bottom yarn and the last 1000m length of the POY surface yarn by 10% is sufficient to guarantee the improved over-tail rate.

[0046] A further improvement is made in that the oil mixture in the oiling process includes crude oil, fluorocarbon surfactants, deionized water and preservatives, and the crude oil is diluted to form a mixed oil with an oil concentration of 8-15%.

[0047] In the oiling process, the crude oil concentration currently used for POY oiling is too high. Therefore, the crude oil needs to be diluted with deionized water to form an oil-based mixture before oiling. However, due to prolonged extrusion, the POY bottom layer filaments tend to stick to the paper tube. Furthermore, since 90% of the POY oil is water, the water melts the parchment adhesive on the paper tube surface, causing some of the bottom layer filaments to stick to the adhesive. This leads to the bottom layer filaments breaking during the finishing process, affecting the finishing yield. Therefore, a fluorocarbon surfactant is added to the crude oil. Because fluorocarbon surfactants contain hydrophobic carbon and fluorine elements, they possess both hydrophobic and oleophobic properties. This solves the problem of the bottom layer filaments melting the adhesive on the paper tube and sticking together during prolonged storage, which causes breakage during the finishing process.

[0048] A further improvement is made to the fact that the carbon and fluorine content in the mixed oil solution is 10.5 to 13.5 wt%.

[0049] If the amount of fluorinated hydrocarbons added is too low, a hydrophobic oil formulation with good properties cannot be obtained; if the amount of fluorinated hydrocarbons added is too high, other performance indicators of the oil formulation will be affected. Therefore, the content of fluorinated hydrocarbon surfactants in crude oil needs to be controlled within a certain range. Among them, when the content of fluorinated hydrocarbons is 10.5–13.5 wt% of the crude oil mixture, the stability is better.

[0050] A further improvement is that the content of the preservative is 0.5-1%, which can ensure its anti-corrosion effect without affecting the performance of the oil-coated filament bundles.

[0051] A further improvement is made by adding a polyoxyethylene-type nonionic surfactant to the oil mixture.

[0052] The addition of fluorocarbon surfactants solved the problem of adhesion between the tow and POY paper tube. However, since the fluorocarbon chain is a hydrophobic and oleophobic group, it is not easy to mix evenly with deionized water. Polyoxyethylene nonionic surfactants were added to the oil mixture. When the oil contains nonionic polyoxyethylene, it can improve the mixing uniformity of crude oil and water, and solve the problem that the fluorocarbon components in the fluorocarbon surfactant are not easy to mix evenly with deionized water.

[0053] Existing oiling agents do not contain fluorocarbon surfactants. When POY is stored for a long time, the water in the oiling agent can melt the cured adhesive on the parchment paper attached to the paper tube, causing some of the bottom fibers to stick to the adhesive. This invention solves the problem of bottom fibers melting the adhesive and sticking to the paper tube by adding a fluorocarbon surfactant. Because fluorocarbon surfactants contain both hydrophobic carbon and fluorine elements, they possess both hydrophobic and oleophobic properties, thus solving the problem of bottom fibers sticking to the paper tube after melting. Simultaneously, a polyoxyethylene nonionic surfactant is added to the oiling agent to improve the uniformity of mixing between crude oil and water. Since the oiling agent concentration for POY is typically 8-15% (i.e., 8-15% crude oil and 85-92% deionized water), the addition of fluorocarbon surfactants, whose fluorocarbon chains are hydrophobic and oleophobic, makes them difficult to mix uniformly with deionized water. The nonionic polyoxyethylene surfactant solves this problem.

[0054] The tail end condition of the silk cake obtained by the above oil-enhancing method is shown in Examples 1-7:

[0055] Example 1

[0056] After approximately 24 hours of balancing time, the success rate of POY yarn cakes directly used for texturing is as follows: For both POY and DTY yarn cakes, the production process remains unchanged. An oil mixture containing fluorocarbon surfactants and polyoxyethylene nonionic surfactants is used to increase the oil content of the POY bottom and surface yarns of each POY yarn cake to 8%. The yarn cakes are then divided into two categories: those directly used for texturing and those left to stand for 3-4 months before being used for texturing. When used for texturing DTY yarn cakes, both types of POY yarn cakes are continuously produced under normal production conditions for one month. The average success rate of the currently produced products is 97.3%, while the success rate of products left to stand for 3-4 months before being used is approximately 95.7%.

[0057] Examples 2-7

[0058] Compared with Example 1, other process conditions remained unchanged, only the oil content of the POY bottom yarn and POY surface yarn in each POY yarn cake was increased. The average success rate of the current production product and the success rate of the product after being put into production for 3 to 4 months are shown in Table 1.

[0059] Comparative Example 1

[0060] Compared with Example 1, the oil content of the POY bottom layer yarn and the top layer yarn did not increase; the production process of POY yarn cake and DTY yarn cake remained unchanged. Each POY yarn cake was oiled with an oil mixture containing fluorocarbon surfactant and polyoxyethylene nonionic surfactant. The yarn cake was then divided into two cases: one for direct use and the other for use after being stored for 3-4 months. When used for texturing DTY yarn cake, the POY yarn cakes under both cases were continuously produced under normal production conditions for 1 month. The average success rate of the finished product was 96.1%, while the success rate of the product after being stored for 3-4 months was about 94.2%.

[0061] Comparative Example 2

[0062] Compared to Example 2, the oil content of the bottom layer yarn and the top layer yarn increased consistently. The production process for POY yarn cakes and DTY yarn cakes remained unchanged, but no fluorocarbon surfactants and polyoxyethylene nonionic surfactants were added to the oil mixture when oiling each POY yarn cake. The yarn cakes were then divided into two cases: those that were put into production directly and those that were put into production after being left to stand for 3-4 months. When used for texturing DTY yarn cakes, the POY yarn cakes in both cases were continuously produced under normal production conditions for 1 month. The average success rate of the finished product was 96.8%, while the success rate of the product put into production after being left to stand for 3-4 months was about 93.5%.

[0063] Comparative Example 3

[0064] Compared to Example 4, the oil content of the bottom and top layers of yarn increased consistently. The production process for POY and DTY yarn cakes remained unchanged, but no fluorocarbon surfactants or polyoxyethylene nonionic surfactants were added to the oil mixture when oiling each POY yarn cake. The yarn cakes were then divided into two categories: those that were directly put into production and those that were placed for 3-4 months before being put into production. When used to synthesize DTY yarn cakes, the POY yarn cakes in both categories were continuously produced for 1 month under normal production conditions. The average success rate of the finished product was 97.9%, while the success rate of the product that was placed for 3-4 months before being put into production was approximately 94.1%.

[0065] Table 1 shows the oil content and corresponding finishing success rate of the products from Examples 1-7 and Comparative Examples 1-3:

[0066] Table 1

[0067]

[0068]

[0069] The tailing success rate is calculated as: (Number of yarns that did not break during tailing) * 100% / Total number of yarns tailed. Table 1 shows that when no fluorocarbon surfactants or polyoxyethylene nonionic surfactants are added to the oil mixture, simply increasing the percentage of the oil mixture can improve the tailing success rate of the currently produced product. However, over time, this can easily lead to an increase in the number of broken POY bottom yarns during tailing, and the longer the storage time, the higher the tailing breakage rate. However, when the oil content of the POY bottom yarn and POY surface yarn on the POY yarn cake is increased to 8-14% using an oil mixture containing fluorocarbon surfactants and polyoxyethylene nonionic surfactants, the tailing success rate of the product can be significantly improved after at least three months of storage, ensuring a good tailing success rate even after a certain period of storage. Especially when the oil content increases to 11%, not only is the tailing success rate guaranteed after a period of storage, but the tailing success rate of the currently produced product is also improved. Furthermore, the addition of oil prevents the formation of tar in the DTY yarn cake later on.

[0070] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A method for improving the success rate of POY over-end, characterized in that: The POY cake is made by slurry configuration, esterification, polycondensation, metering, melt extrusion of spinneret, cooling, oiling and winding, and the oil content of the POY bottom layer yarn and the last 1000 m POY surface yarn of each POY cake is increased by 8-15% during the spinning of the POY yarn, and the oil content of the middle part of the POY yarn is unchanged; The method for increasing the oil content of the 1000 m surface yarn and the 1000 m bottom layer yarn of the cake includes: Step 1, first calculate the full winding time T1 of a falling yarn, T1 = winding weight * 10000 / specification * spinning speed; Step 2, then calculate the time T2 required for 1000 m yarn to pass through the oiling process, T2 = 1000 m / spinning speed; Step 3, set the oil pump oiling frequency in the oiling process to increase the oil content of the passing yarn, and the oil pump oiling frequency increase time is T2 for the bottom layer of the first falling cake after the new head, T1-T2 for the surface yarn of the first falling cake, and T1+T2 for the bottom layer of the second falling yarn; Step 4, automatically control the oil pump oiling frequency increase according to the time T2 required for the oiling process, so that the oil content of the yarn passing within T2 is increased, thereby increasing the oil content of the 1000 m yarn within the bottom layer of the first falling cake after the new head; Step 5, calculate the oil pump oiling frequency increase time required for the 1000 m yarn within the surface yarn of the first falling cake after the new head and the 1000 m yarn within the bottom layer of the second falling cake according to the time T1-T2 to T1+T2, and increase the frequency of the oil pump during the time T1-T2 to T1+T2 to increase the oil content of the 1000 m yarn within the surface yarn of the first falling cake after the new head and the 1000 m yarn within the bottom layer of the second falling cake; Step 6, calculate the oil pump oiling frequency increase time required for the 1000 m yarn within the surface yarn of the second falling cake after the new head and the 1000 m yarn within the bottom layer of the third falling cake according to the time 2*T1-T2 to 2*T1+T2, and increase the frequency of the oil pump during the time 2*T1-T2 to 2*T1+T2 to increase the oil content of the 1000 m yarn within the surface yarn of the second falling cake after the new head and the 1000 m yarn within the bottom layer of the third falling cake; Step 7, calculate the oil pump oiling frequency increase time required for the 1000 m yarn within the surface yarn of the Nth falling cake after the new head and the 1000 m yarn within the bottom layer of the Nth falling cake according to the calculation method of the time N*T1-T2 to N*T1+T2, and increase the frequency of the oil pump during the time N*T1-T2 to N*T1+T2 to increase the oil content of the 1000 m yarn within the surface yarn of the Nth falling cake after the new head and the 1000 m yarn within the bottom layer of the Nth falling cake.

2. The method for improving the success rate of POY over-end according to claim 1, characterized in that: The processing method for the cake after the stop in the continuous production process includes: Step 1, the oil pump needs to be turned off and the related problems need to be handled; Step 2, restart the oil pump, and then according to the surface yarn 1000m of the yarn cake and the bottom layer yarn 1000m of the yarn cake, the oil pump is automatically controlled by recalculating the oil output frequency increase time.

3. The method for improving the success rate of POY over-end according to claim 1 or 2, characterized in that: The oil content of the POY bottom layer yarn and the last 1000m of the POY surface yarn of each POY yarn cake with an initial length of 0-1000m is increased by 8-12%.

4. The method for improving the success rate of POY over-end according to claim 1, characterized in that: The oil mixture of the oiling process comprises crude oil, fluorocarbon surfactant, deionized water and preservative, and the crude oil forms a mixed oil with an oil concentration of 8-15% after dilution.

5. The method for improving the success rate of POY over-end according to claim 4, characterized in that: The content of the preservative is 0.5-1%.

6. The method for improving the success rate of POY over-end according to claim 4, characterized in that: The fluorocarbon content in the mixed oil mixture is 10.5-13.5wt%.

7. The method for improving the success rate of POY over-end according to claim 4, characterized in that: The mixed oil also contains polyoxyethylene nonionic surfactant.

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