阅读说明：本技术 回收耐隆纤维及其制造方法 (Recycled nylon fiber and manufacturing method thereof ) 是由 黄冠融 纪博文 廖骏鸿 柯文翌 于 2018-06-29 设计创作，主要内容包括：一种回收耐隆纤维及其制造方法。回收耐隆纤维的制造方法包含提供一耐隆纤维废料、进行一破碎步骤、进行一水洗步骤、进行一脱水挤干步骤、进行一熔融造粒步骤以及进行一熔融纺丝步骤,以获得一回收耐隆纤维。借此,可使用已过油的耐隆6纤维废料或已过油的耐隆66纤维废料进行纺丝,有利于耐隆纤维废料的再利用,且可提升产品价格并满足环保诉求。(A recycled nylon fiber and a manufacturing method thereof. The manufacturing method of the recycled nylon-rich fiber comprises the steps of providing nylon-rich fiber waste, carrying out a crushing step, carrying out a water washing step, carrying out a dewatering and squeezing step, carrying out a melt granulation step and carrying out a melt spinning step so as to obtain the recycled nylon-rich fiber. Therefore, the oily nylon-6-resistant fiber waste or the oily nylon-66-resistant fiber waste can be used for spinning, recycling of the nylon-resistant fiber waste is facilitated, the product price can be increased, and the environment-friendly requirement can be met.)

1. A method for producing recycled nylon fibers, comprising:

providing a nylon-resistant fiber waste, wherein the nylon-resistant fiber waste is oil-treated nylon-resistant 6 fiber waste or oil-treated nylon-resistant 66 fiber waste;

a crushing step is carried out, wherein the nylon-resistant fiber waste is crushed to form a plurality of nylon-resistant fiber fragments;

performing a water washing step, namely washing the nylon fiber fragments with water to reduce the oil content of the nylon fiber fragments to be less than 0.22 wt%;

performing a dewatering and squeezing step to remove the water content of the nylon fiber fragments to form a plurality of nylon sheets, wherein the water content of the nylon sheets is less than or equal to 4 wt%;

performing a melt granulation step, namely melting and granulating the durable wafer to form a plurality of recovered durable granules; and

performing a melt spinning step to melt spin the recycled nylon particles to obtain a recycled nylon fiber.

2. The process according to claim 1, wherein the waste nylon-6-containing yarn comprises nylon-6-base full-gloss yarn, nylon-6-semi-gloss yarn, nylon-6-base matte yarn, nylon-6-base color yarn, nylon-66-base full-gloss yarn, nylon-66-base matte yarn, nylon-66-base ultra-high strength yarn, nylon-66-high strength color yarn, nylon-66-pinney-high strength yarn, nylon-6-net waste, nylon-66-net waste, nylon-6-base waste or nylon-66-base waste.

3. The method as claimed in claim 1, wherein the fragments of nylon fiber have a maximum length of 3cm to 5 cm.

4. The method for producing recycled nylon-based fibers according to claim 1, wherein the water washing time in the water washing step is 10 to 20 minutes.

5. The method for manufacturing recycled nylon-containing fibers according to claim 1, wherein the dewatering and wringing step comprises:

performing a dehydration step, namely dehydrating the nylon fiber chips to reduce the moisture of the nylon fiber chips to below 10 wt%; and

and (3) carrying out a squeezing step, namely squeezing the nylon fiber fragments subjected to the dehydration step to form the nylon rubber sheets.

6. The method for producing recycled nylon-based fibers according to claim 1, further comprising:

and a drying step, namely drying the recycled nylon particles to ensure that the moisture of the recycled nylon particles is 300ppm to 700 ppm.

7. The method for producing recycled nylon-containing fiber according to claim 6, wherein the drying step is performed at 70 ℃ to 85 ℃ for 1 day to 3 days.

8. The method of claim 1, wherein the recycled nylon fiber is a half-drawn fiber or a fully drawn fiber.

9. The method for manufacturing recycled nylon-based fiber according to claim 1, wherein the melt-spinning step comprises:

performing a melting step of melting the recycled anti-swelling particles to form a spinning solution;

a spinning step is carried out, wherein the spinning solution passes through a spinning nozzle plate to form a plurality of spinning yarns;

a cooling step is carried out, which is to cool the spinning yarns to form a plurality of solidified yarns;

performing cluster oiling, namely performing cluster oiling on the solidified wires to form a cluster wire;

performing a drafting step to stretch the bunched yarn to form an extended yarn; and

a step of coiling is carried out, which is to wind the extension wire on a column piece to obtain the recycled nylon fiber.

10. A recycled nylon fiber, characterized in that it is produced by the process for producing a recycled nylon fiber according to any one of claims 1 to 9.

Technical Field

The present invention relates to a nylon-containing fiber and a method for manufacturing the same, and more particularly, to a recycled nylon-containing fiber and a method for manufacturing the same.

Background

In recent years, with the rise of global environmental issues such as ozone depletion, greenhouse effect, acid rain, disappearance of tropical rain forests, desertification and the like, people are made to realize unlimited use of existing resources, balance between the natural environment and the development of the people is endangered, and the sustainable stability of environmental ecology is required to be ensured in order to achieve the sustainable development of the human society.

Therefore, how to recycle the existing resources is an object of efforts. In the case of waste carpeting, 10 million kilograms of waste carpeting are discarded annually in a single country in the united states, and if not recycled, a large amount of land is required for landfilling. In 2009, evergreen recovery companies recovered old carpet weighing up to 3.11 hundred million pounds, with a reusable portion of up to 2.46 million pounds, with recovery exceeding 2008. The evergreen recycling company in the United states plans to improve the recycling rate by 20-25% again in 2012. The old carpet is mostly made of nylon fiber. The conventional nylon-resistant fibers include nylon-resistant 6 fibers and nylon-resistant 66 fibers, and there is a high technical difficulty in recycling the nylon-resistant fibers to produce high-quality fibers, and it is known that companies develop a chemical decomposition type technical solution in which recycled nylon-resistant fibers subjected to chemical decomposition treatment are combined with new materials (i.e., non-recycled waste materials) for reuse, and the recycling rate of the nylon-resistant fibers has been greatly increased under the efforts of the companies.

However, the method requires chemical treatment of the recycled nylon fiber for subsequent utilization, which is complicated in process, and the method requires addition of new materials, i.e., the obtained product is not 100% recycled nylon waste product.

Furthermore, because of the manufacturing process, the currently common nylon-based fiber waste comprises non-oiled nylon-based fiber waste and oiled nylon-based fiber waste, wherein the non-oiled nylon-based fiber waste can be directly melt-granulated, and the obtained nylon-based particles (or referred to as chips) can be directly spun, whereas the oiled nylon-based fiber waste has the defect of too high filament breakage rate when the nylon-based particles obtained by melt-granulation are applied to spinning, so that the yield is too low, the nylon-based fiber waste is not suitable for being used as a spinning material, and only can be sold as general engineering plastics and products, and a better selling price cannot be obtained.

Disclosure of Invention

The invention aims to provide a manufacturing method for recycling nylon-resistant fibers, wherein the used nylon-resistant fiber waste is oil-treated nylon-resistant 6 fiber waste or oil-treated nylon-resistant 66 fiber waste, and the nylon-resistant particles obtained by melt granulation are favorably applied to spinning by properly treating the nylon-resistant fiber waste, so that the product price can be increased. In addition, the manufacturing method of the recycled nylon fiber does not need to carry out chemical treatment on the nylon fiber waste before carrying out melt granulation, and is simple in manufacturing process.

The invention also aims to provide a recycled nylon fiber, which can completely use waste nylon fiber as a raw material, is beneficial to recycling the waste nylon fiber and meets the requirement of environmental protection.

According to an embodiment of the present invention, a method for recycling nylon includes providing a waste nylon, performing a crushing step, performing a water washing step, performing a dewatering and squeezing step, performing a melt granulation step, and performing a melt spinning step. The nylon-resistant fiber waste is oil-treated nylon-resistant 6 fiber waste or oil-treated nylon-resistant 66 fiber waste. The crushing step is to crush the nylon waste to form a plurality of nylon chips. The water washing step is to wash the nylon fiber fragments to reduce the oil content of the nylon fiber fragments to below 0.22 wt%. The dewatering and squeezing step is to remove the water content of the nylon fiber fragments to form a plurality of nylon rubber sheets, and the water content of the nylon rubber sheets is less than or equal to 4 wt%. The melt granulation step is melt granulation of the nylon chip to form a plurality of recycled nylon granules. The melt spinning step is melt spinning the recycled nylon particles to obtain recycled nylon fibers.

According to the aforementioned method for producing recycled nylon, the waste nylon yarn may comprise nylon 6 full-gloss yarn, nylon 6 semi-gloss yarn, nylon 6 matt yarn, nylon 6 color yarn, nylon 66 full-gloss yarn, nylon 66 semi-gloss yarn, nylon 66 matt yarn, nylon 66 ultra-high strength yarn, nylon 66 high strength color yarn, nylon 66 fine denier high strength yarn, nylon 6 fishing net waste yarn, nylon 66 fishing net waste yarn, nylon 6 waste cloth, or nylon 66 waste cloth.

According to the foregoing method for manufacturing recycled nylon, the maximum length of the nylon chips may be 3cm to 5 cm.

According to the foregoing method for manufacturing recycled nylon fibers, the washing time of the washing step may be 10 minutes to 20 minutes.

According to the manufacturing method of the recycled nylon fiber, the dewatering and squeezing step may comprise a dewatering step and a squeezing step. The dehydration step is to dehydrate the nylon fiber chips to reduce the water content of the nylon fiber chips to below 10 wt%. The squeezing step is to squeeze the nylon fiber fragments subjected to the dehydration step to form the nylon rubber sheet.

According to the above-mentioned method for producing recycled nylon fibers, a drying step of drying the recycled nylon particles to a moisture content of 300ppm to 700ppm may be further included. The drying step may be carried out at 70 ℃ to 85 ℃ for 1 day to 3 days.

According to the manufacturing method of the recycled nylon fiber, the recycled nylon fiber can be a semi-extended fiber or a fully extended fiber.

According to the manufacturing method of the recycled nylon fiber, the melt spinning step may comprise performing a melting step, performing a spinning step, performing a cooling step, performing a cluster oiling step, performing a drawing step, and performing a curling step. The melting step melts the recycled hard pellets to form a spin dope. The spinning step is to make the spinning solution pass through a spinning nozzle plate to form a plurality of spinning nozzle yarns. The cooling step is to cool the spun yarn to form a plurality of solidified yarns. The bundling and oiling step is to perform bundling and oiling on the solidified silk to form bundling silk. The drawing step is to extend the bundled yarn to form an extended yarn. And a curling step, namely winding the extension wires on a column to obtain the recycled nylon fiber.

According to another embodiment of the present invention, a recycled nylon fiber is provided, which is produced by the above-mentioned method for producing recycled nylon fiber.

Drawings

FIG. 1 is a flow chart of the steps of a method of making recycled nylon fiber according to one embodiment of the present invention;

FIG. 2 is a flowchart of the steps of step 140 in FIG. 1;

FIG. 3 is a flowchart of the steps of step 160 of FIG. 1;

FIG. 4 is a schematic view of the melt spinning apparatus of step 160 of FIG. 3; and

FIG. 5 is a flow chart of steps in a method of making recycled nylon-based fibers according to another embodiment of the present invention.

Detailed Description

In the present invention, "fiber" refers to a product obtained in a melt spinning step, and sometimes the fiber may be named differently according to different characteristics, for example, the fiber may be divided into monofilament, multi-strand filament, staple fiber yarn, twin-strand yarn, and composite yarn according to different shape structures; the yarn is classified into a plenoptic yarn, a semi-gloss yarn and a matt yarn according to the difference in gloss, in other words, the "fiber" in the present invention is a general term for different yarns (i.e., the most common term).

< method for producing recycled nylon fibers >

Referring to fig. 1, a flow chart of steps of a method 100 for manufacturing recycled nylon fibers according to an embodiment of the invention is shown. In fig. 1, the method 100 for manufacturing recycled nylon-based fibers includes step 110, step 120, step 130, step 140, step 150, or step 160.

Step 110 is to provide a waste of nylon-resistant fibers, which is waste of oil-treated nylon-resistant 6 fibers or waste of oil-treated nylon-resistant 66 fibers. The "processed oil" refers to the nylon fiber waste material, which contains the step of oiling by using oil tanker or oil nozzle during the preparation process, and the details about how to oil by using oil tanker or oil nozzle and the types of oil that can be used are not repeated herein for the conventional technology in the spinning field.

Step 120 is a crushing step, which is to crush the nylon waste to form a plurality of nylon fragments.

Step 130 is a water washing step of washing the nylon fiber chips with water to reduce the oil content of the nylon fiber chips to 0.22 wt% or less.

Step 140 is a dewatering and wringing step that removes water from the nylon fiber chips to form a plurality of nylon sheets having a moisture content of 4 wt% or less.

Step 150 is a melt granulation step, wherein the nylon sheet is melt granulated to form a plurality of recycled nylon granules.

Step 160 is a melt spinning step of melt spinning the recycled nylon particles to obtain a recycled nylon fiber.

Therefore, the waste of the anti-bloom fiber used in the manufacturing method 100 for recycling the anti-bloom fiber is the waste of the anti-bloom 6 fiber which has been subjected to oil or the waste of the anti-bloom 66 fiber which has been subjected to oil, and the anti-bloom particle obtained by melt granulation is beneficial to being applied to spinning by properly treating the waste of the anti-bloom fiber, so that the product price can be increased. In addition, the manufacturing method of the recycled nylon fiber does not need to carry out chemical treatment on the nylon fiber waste before carrying out melt granulation, and is simple in manufacturing process.

The following is a more detailed description of the method 100 for producing recycled nylon fibers.

In step 110, the waste nylon-resistant fiber may include, but is not limited to, nylon-6 full-gloss yarn, nylon-6 semi-gloss yarn, nylon-6 matt yarn, nylon-6 full-gloss yarn, nylon-66 semi-gloss yarn, nylon-66 matt yarn, nylon-66 ultra-high strength yarn (fiber strength >8.5g/d), nylon-66 high strength yarn (fiber strength >8.0g/d), nylon-66 fine denier high strength yarn (fiber strength >7.5g/d), nylon-6 fishing net waste, nylon-66 fishing net waste, nylon-6 waste, or nylon-66 waste. Specifically, the nylon waste can be secondary long fiber recycled by customers, secondary long fiber recycled by the process or waste nylon wire, wherein the secondary fiber refers to leftovers in the production, namely the quality does not reach the AA grade, and the AA grade refers to no broken fiber, no coil drop of spinning cake and no net wire generation. Before step 110, the recycled waste nylon-6 yarns may be sorted, for example, nylon-6 full yarns are classified into one category, nylon-6 semi-gloss yarns are classified into another category, nylon-6 dull yarns are classified into another category, and so on, and after sorting, the subsequent steps are performed. In other words, the waste nylon-based fibers in step 110 belong to the same category, thereby facilitating the control of the conditions of the melt spinning step and improving the yield and quality of the recycled nylon-based fibers.

In step 120, the formed nylon-resistant fiber fragments may have a maximum length of 3cm to 5 cm. Therefore, the oil content in the nylon fiber fragments can be reduced in the subsequent water washing step. Step 120 may be performed in a crusher. In addition, the waste high-tenacity fibers from step 110 may be conveyed to the crusher from step 120 using a conveyor belt.

In step 130, the water washing time of the water washing step may be 10 minutes to 20 minutes. Step 130 may be performed in a water wash tank. In addition, the nylon fiber chips in step 120 may be transferred to the rinsing bath in step 130 using a conveyor belt.

Step 140 may take two stages to perform the dehydration. Referring collectively to FIG. 2, a flowchart illustrating the steps of step 140 of FIG. 1 is shown. In fig. 2, step 140 may comprise step 141 or step 142.

Step 141 is a dewatering step that dewaters the nylon-containing fiber chips to reduce the moisture of the nylon-containing fiber chips to less than 10 wt%. Step 141 may be performed in a dehydration engine.

Step 142 is a drying step, which is to dry the nylon-containing fiber fragments subjected to the dehydration step to form a nylon-containing sheet, wherein the moisture content of the nylon-containing sheet is less than or equal to 4 wt%. Step 142 may be performed in a wringer.

In step 150, the nylon film is fed into an extruder for granulation to obtain recycled nylon granules, and the granulation conditions can be adjusted according to the application of the recycled nylon granules, so as to compare with the non-recycled nylon granules. The resulting recycled nylon particles may be packaged for storage and removed from the packaging for use (e.g., step 160), for example, in a gravity-based space bag.

In step 160, the recycled nylon fibers may be semi-extended fibers or fully extended fibers, depending on the conditions of the melt spinning step.

Referring collectively to FIG. 3, a flowchart illustrating the steps of step 160 of FIG. 1 is shown. In fig. 3, step 160 may include step 161, step 162, step 163, step 164, step 165, and step 166.

Step 161 is a melting step to melt the recycled nylon particles to form a spin dope. The temperature of the melting step may be, but is not limited to, 260 ℃ to 300 ℃.

Step 162 is to perform a spinning step by passing the spinning solution through a spinneret to form a plurality of spun filaments.

Step 163 is a cooling step that cools the spun filaments to form a plurality of solidified filaments. The cooling step may be carried out at a temperature of from 13 ℃ to 20 ℃.

Step 164 is a cluster oiling step, which clusters the solidified filaments to form a cluster of filaments. The cluster oiling step can utilize oil tanker or oil nozzle oiling.

Step 165 is a drawing step that extends the bundled filaments to form an extended filament. The draft Ratio (Draw Ratio) of the draft step is 1.2 to 1.5. The draft ratio is calculated in such a manner that the output speed/input speed is low, and when the draft ratio is lower than 1.2, yarn breakage is likely to occur, and when the draft ratio is higher than 1.5, excessive drawing is likely to occur, resulting in breakage of the cured yarn. In addition, the drawing step can also comprise a heating step which is carried out at the temperature of 145 ℃ to 200 ℃, so that the solidified silk can be subjected to heat setting, when the temperature is too high, the solidified silk shakes violently on the drawing wheel, the tension is too small to be hung and spun into silk, and when the temperature is too low, the heat setting of the solidified silk is insufficient, the internal stress of a molecular chain is increased, and the forming of a spinning cake is not easy to control. The physical properties of the bundled yarn, such as strength or elongation, can be changed by the drawing step to convert the bundled yarn into an extended yarn.

Step 166 is a crimping step that winds the drawn filaments around a post to obtain recycled nylon fiber. The crimping step may wind the drawn wire at a rotation speed of 2500m/min to 5000 m/min. The physical properties of the drawn yarn, such as strength or elongation, can be altered by the crimping step to convert the drawn yarn into recycled nylon fiber.

In addition, the condition parameters from step 161 to step 166 can be adjusted according to the type of the recycled nylon particles. Specifically, when the anti-blooming fiber waste in step 110 belongs to a anti-blooming 6 full-gloss yarn, the recycled anti-blooming particle formed in step 150 is a full-blooming 6 particle, when the anti-blooming fiber waste in step 110 belongs to a anti-blooming 6 semi-gloss yarn, the recycled anti-blooming particle formed in step 150 is a semi-blooming anti-blooming 6 particle, when the anti-blooming fiber waste in step 110 belongs to a anti-blooming 66 semi-gloss yarn, the recycled anti-blooming particle formed in step 150 is a semi-blooming anti-blooming 66 particle, and so on, because the different types of recycled anti-blooming particles have different required condition parameters, the required condition parameters can be adjusted accordingly according to the types of the recycled anti-blooming particles. For example, in step 161, the melting points of the semi-light nylon 66 particles and the semi-light nylon 6 particles are different, so the temperature of the melting step can be adjusted accordingly according to the melting point of the recycled nylon particles. How to adjust the condition parameters from step 161 to step 166 to impart the desired properties to the recovered nylon particles is well known in the art and will not be further described herein.

Please refer to fig. 4, which is a schematic diagram of the melt spinning apparatus in step 160 of fig. 3. In fig. 4, the melt spinning apparatus includes a feed barrel tank 510, an extruder servo motor 520, an extruder 530, a dope pipe 540, a spinning box 550, a cooling device 560, a stretching device 570, and a crimping device 580.

In step 161, the recycled anti-swelling particles are fed into the feeding barrel tank 510, and then fed into the extruder 530 through the feeding barrel tank 510, and the recycled anti-swelling particles are melted in the extruder 530 to form a spinning solution, and the temperature for melting in the extruder 530 may be 260 to 300 ℃.

Then, the extruder servo motor 520 drives the screw (not shown) in the extruder 530 to extrude the spinning solution out of the extruder 530 and make it enter the spinning solution pipe 540, the temperature of the spinning solution pipe 540 can be controlled between 260 ℃ and 300 ℃, and the spinning solution is prevented from being solidified due to temperature reduction before entering the spinning box 550.

In step 162, the spinning solution is introduced into a spinning box 550, and is distributed to each spinning opening 551 by a metering pump (not shown) through a distribution pipe, and the spinning solution passes through a nozzle plate (not shown) provided at the spinning opening 551 to form a nozzle yarn a. The temperature of the manifold 550 can be controlled at 260 ℃ to 300 ℃.

In step 163, the spun yarn is cooled by the cooling device 560 to form a plurality of solidified yarns, and the cooling device 560 may provide a cooling gas having a temperature of 13 ℃ to 20 ℃, a wind speed of 20m/min to 100m/min, and a relative humidity of 45% to 65%.

In step 164, the solidified filament bundle is oiled by an oiling device 561 (such as a nozzle or a tanker) to form a bundled filament, which is not described herein in detail as a conventional technique for oiling the solidified filament bundle.

In step 165, the bundled wire is extended by an extension device 570 to form an extended wire. In this embodiment, the stretching device 570 includes the first draft wheel 571, the second draft wheel 572, and the third draft wheel 573, and the physical properties such as strength and elongation of the produced recycled nylon fiber can be further improved by stretching in multiple stages. In the draft ratio calculation method, the input speed is the rotational speed of the first draft wheel in the stretching device 570, i.e., the rotational speed of the first draft wheel 571 in the present embodiment, the output speed is the rotational speed of the last draft wheel in the stretching device 570, i.e., the rotational speed of the third draft wheel 573 in the present embodiment, and the draft ratio in the drafting step is 1.2 to 1.5. In addition, at least one of the first drawing wheel 571, the second drawing wheel 572 and the third drawing wheel 573 can provide a heating function to heat and shape the bundled filament. The physical properties of the bundled yarn, such as strength or elongation, can be changed by the drawing step to convert the bundled yarn into an extended yarn.

In step 166, the extended filament is wound around a cylindrical member to form a cake (not shown) by the winding device 580, the winding device 580 can provide a rotation speed of 2500m/min to 5000m/min to wind the extended filament, and after the winding step, the physical properties of the extended filament are changed to be converted into recycled nylon fibers, in other words, the fiber of the cake formed by the winding device 580 is recycled nylon fibers.

Referring to fig. 5, a flow chart of steps of a method 200 for manufacturing recycled nylon fibers according to another embodiment of the present invention is shown. In fig. 5, the method 200 for manufacturing recycled nylon-based fibers includes steps 210, 220, 230, 240, 250, 260, and 270.

Step 210 is to provide a nylon waste, step 220 is to perform a crushing step, step 230 is to perform a water washing step, step 240 is to perform a dewatering and squeezing step, step 250 is to perform a melt granulation step, and step 270 is to perform a melt spinning step. Regarding steps 210 to 250 and 270, reference may be made to steps 110 to 160 in fig. 1, which are not described herein again.

Step 260 is a drying step of drying the reclaimed nylon particles obtained in step 250 to a moisture content of 300ppm to 700ppm, and the drying step may be performed at 70 ℃ to 85 ℃ for 1 day to 3 days. The drying step may be carried out in a drying tower. In addition, the recovered durable particles in step 250 may be transported to the drying tower in step 260 using a transport windmill. The resulting dried recycled nylon particles may be packaged for storage and then removed from the package for use (e.g., step 270), which may be gravity-based space-bag packaging.

< recovery of nylon fibers >

The invention provides a recycled nylon-resistant fiber which is prepared by the preparation method of the recycled nylon-resistant fiber, the recycled nylon-resistant fiber completely uses nylon-resistant particles prepared from nylon-resistant fiber waste as raw materials for spinning, in other words, the recycled nylon-resistant fiber is 100 percent recycled nylon-resistant fiber, so that the recycling of the nylon-resistant fiber waste is facilitated, and the requirement of environmental protection is met.

< measurement mode of Properties >

And (3) evaluating the broken wire times: and counting the yarn breaking times within 24 hours, wherein if the yarn breaking times are 1-3 times, the yarn breaking times belong to the AA grade, the yarn breaking times are preferably evaluated, if the yarn breaking times are 4-6 times, the yarn breaking times belong to the A grade, the yarn breaking times are common, and if the yarn breaking times are more than 7 times, the yarn breaking times belong to the B grade, the yarn breaking times are poor.

AA efficiency (%): the production yield reaching the AA grade is calculated as follows: AA efficiency (%) × (number of fibers reaching AA grade)/(number of fibers reaching AA grade + number of fibers not reaching AA grade) ] × 100%. The AA rating means that the fibers were not broken, no knockover of the cake and no net wire was produced.

Fiber Oil content (Oil Pick-Up, OPU) (%): the weight proportion of oil in the fibers was measured by NMR (nuclear Magnetic resonance) and expressed as a percentage.

< examples and comparative examples >