Method for preventing abnormal elongation of polyester filament breakage

Abstract

The present application belongs to the technical field of polyester filament, and discloses a method for preventing abnormal elongation and breaking of polyester filament, which is characterized in that, in the production process of the polyester filament, the surface roughness a* of the second hot roller is measured every 48 hours, and after each measurement, it is determined whether a* is greater than a max If yes, the second hot roller is replaced by a second hot roller with a surface roughness less than a max ; otherwise, no adjustment is made; a max The calculation formula of a is: a max =(1+β×d / f)×a, wherein β is the coefficient corresponding to the cross-sectional type of the polyester filament, f is the number of filaments in the polyester filament, d is the value of the fineness of the polyester filament in denier, and a is the average value of the surface roughness of the second hot roller measured after one month of weaving. The present application can effectively prevent the abnormal elongation and breaking strength of the polyester filament caused by the abnormal roughness of the second hot roller.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyester filaments, and relates to a method for preventing abnormal elongation at break of polyester filaments. BACKGROUND

[0002] In actual production, the elongation at break of polyester fully drawn yarn (FDY), polyester composite yarn, polyester high orientation yarn (HOY), polyester pre-oriented yarn (POY), SYS double-component composite yarn and other polyester filaments is often uneven, and the elongation at break and the breaking strength are both low. This situation is usually measured by sampling inspection of corresponding physical properties. When the abnormality is found, a period of abnormal yarn has been produced, and it is necessary to track and reduce the grade, which greatly affects the production index. The specific performance and reasons are as follows:

[0003] Uneven elongation at break: in the continuous production process, the abnormal elongation at break of the multi-spindle yarn at the spinning position may be caused by the roughness change caused by the wear of the hot roller. The position of the hot roller corrosion and friction is not fixed. If it occurs at the position where the yarn is often rubbed, the physical property will be abnormal for the single-spindle yarn, and the deviation is larger than that of the remaining spindle positions, which is reflected in the large CV value of the corresponding spindle of the spinning position. If the corrosion occurs between the two yarns, the elongation at break of the two yarns will be measured from time to time, which is caused by the back and forth movement of the yarn on the hot roller during production. The normal yarn cannot be completely determined because the deviation of the test results is large. In addition, the roughness of the hot roller is large, which will cause the deviation of the same variety to be larger than the remaining spindle positions. Since the CV value reflects the deviation, the CV value will be large.

[0004] Low elongation at break and low breaking strength: it is mainly caused by the fiber wear during the production of the yarn bundle. The first hot roller (GR1) is a metal chromium plating coating, which rarely has large area roughness change, and only has fixed point injury and scratch, which is generally reflected in the production as broken head, but not in the low elongation at break and low breaking strength. The second hot roller (GR2) is different. Long-term high-temperature oil corrosion may cause the peeling of the ceramic shell of the second roller or the increase of the roughness, which may cause the normal production but the low elongation at break and low breaking strength of the produced yarn cake. Since different fiber varieties can adapt to different hot roller roughness, when the same equipment needs to produce different varieties of polyester fibers, a large number of abnormal yarns may be produced, which may cause the grade to be reduced. In addition, in actual production, the abnormality is not found in time, and a large number of polyester filaments with abnormal elongation at break need to be tracked and reduced, which seriously affects the production index.

[0005] The patent application with the application publication number CN104846450A discloses a polyester filament continuous spinning device, which comprises a screw extruder, a hopper connected above the screw extruder, and a spinning assembly arranged below the screw extruder. A filament chamber for spinning cooling is arranged below the spinning assembly, and a first buncher, a first hot roller, a second hot roller, a second buncher and a winding roller are sequentially arranged along the spinning route below the filament chamber. A friction roller is mounted on the outer periphery of the winding roller. However, during actual production, the roughness of the second hot roller changes, which causes the breaking elongation and breaking strength of the prepared polyester fiber to be low at the same time when different types of polyester fibers are prepared.

[0006] The patent application with the application publication number CN201365353Y discloses a ceramic-coated electric heating roller, which comprises a tubular roller core, a ceramic electric heating layer coated on the outer surface of the roller core, a conductive copper sheet and a power electrode connected with the ceramic electric heating layer at both ends of the roller core, and a ceramic insulating layer arranged between the ceramic electric heating layer and the outer surface of the roller core. However, the surface roughness Ra (0.025-0.80) of the heating roller is suitable for most conventional varieties, but it may affect the fiber properties for some fine denier fibers with special cross-section. Moreover, the roughness is a characteristic when the heating roller is not in use, and the surface roughness changes after a period of use due to the effects of high-temperature oil and fiber friction. The patent does not particularly describe the anticorrosion, friction and roughness increase of the ceramic roller surface.

[0007] Therefore, it is necessary to provide a method for preventing abnormal breaking elongation of polyester filaments, which has great significance in solving the above problems. SUMMARY

[0008] The purpose of the present application is to solve the problems existing in the prior art and provide a method for preventing abnormal breaking elongation of polyester filaments.

[0009] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0010] A method for preventing abnormal breaking elongation of polyester filaments, the production process of the polyester filaments comprising a drawing and setting process. In the drawing and setting device, only the surface of the second hot roller contains a ceramic coating layer. During the production process of the polyester filaments, the surface roughness a* of the second hot roller is measured every certain period of time. After each measurement, it is determined whether a* is greater than a max If yes, the second hot roller is replaced with a second hot roller with a surface roughness less than a max ; otherwise, no adjustment is made.

[0011] The certain period of time is 48 hours, and the value of N can be adjusted according to the actual production situation.

[0012] a maxThe calculation formula is as follows:

[0013] a max =(1+β×d / f)×a;

[0014] In the formula, β is a coefficient corresponding to the section type of the polyester filament; when the section type of the polyester filament is circular, β is 1; when the section type of the polyester filament is triangular, β is 0.9; when the section type of the polyester filament is trilobal, β is 0.8; and when the section type of the polyester filament is hollow, β is 0.6;

[0015] f is the number of filaments in the polyester filament;

[0016] d is the value of the fineness of the polyester filament in denier;

[0017] a is the average value of the surface roughness of the second heat roller measured after spinning for one month, so as to eliminate the influence of oil dirt and other test conditions after spinning.

[0018] According to the ISO 1302 international standard, when the surface roughness of the heat roller is less than 0.8 μm, the surface of the heat roller has reached the machining precision of the fine grinding level. The present application does not directly set a max 0.8 μm, but re-sets a max according to the section type of the polyester filament, the number of filaments in the polyester filament, the fineness of the polyester filament, and the original surface roughness of the second heat roller, so as to effectively prevent the abnormal elongation of the polyester filament while maximizing the use time of the second heat roller and reducing the efficiency loss caused by frequent replacement of the heat roller.

[0019] As a preferred technical solution:

[0020] The method for preventing the abnormal elongation of the polyester filament as described above, when measuring the surface roughness a* of the second heat roller at intervals, 2-3 data are obtained each time, and the average value of the data is calculated as the final result a* of this measurement.

[0021] The method for preventing the abnormal elongation of the polyester filament as described above, a is the average value of the surface roughness of the second heat roller measured after spinning for one month.

[0022] The method for preventing the abnormal elongation of the polyester filament as described above, the production process of the polyester filament is: melting → extrusion by a spinneret plate → cooling → oiling → pre-networking (the function is to disperse the oil agent) → first heat roller stretching → first filament splitting roller → second heat roller heat setting → second filament splitting roller → main networking → winding.

[0023] The method for preventing abnormal elongation of polyester filament yarns as described above, the production process parameters of the polyester filament yarns are: cooling air pressure is 135 Pa, cooling air temperature is 450 DEG C, cooling air humidity is 21.4 % RH, the cooling mode is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt %, the preservative concentration is 400 ppm, the pre-networking pressure is not more than 0.5 bar, the main networking pressure is not more than 5 bar, the first hot roller (GR1) speed is not more than 3000 m / min, the first filament separating roller (SR1) speed is not more than 3000 m / min, the first hot roller temperature (HT1) is not more than 140 DEG C, the second hot roller (GR2) and the second filament separating roller (SR2) speed is 3000-5500 m / min, the second hot roller temperature (HT2) is not more than 140 DEG C, the winding speed is 3000-5500 m / min, the first hot roller winding turns is 8.5 turns, the second hot roller winding turns is 5.5 turns; the polyester terephthalate is selected as the main component of the slice or melt, the filament is extruded through the metering pump and the corresponding cross-section spinneret plate, and the drawn yarn is prepared through the cooling, oiling, first and second guide hot roller spinning stretching one-step process and networker false twist.

[0024] The method for preventing abnormal elongation of polyester filament yarns as described above, the production process flow of the polyester composite yarns is: polyester POY yarn (pre-oriented yarn) and polyester FDY yarn (fully drawn yarn) are combined→ ply networking→ second hot roller→ winding.

[0025] The production process flow of the polyester POY yarn is: polyester melt→ spinneret plate extrusion→ cooling→ oiling→ guide disc.

[0026] The production process flow of the polyester FDY yarn is: polyester melt→ spinneret plate extrusion→ cooling→ oiling→ pre-networking (the function is to disperse oil agent)→ first hot roller.

[0027] The method for preventing abnormal elongation of polyester filament breakage as described above, the production process parameters of the polyester composite filament are: cooling air pressure is 135 Pa, cooling air temperature is 450 DEG C, cooling air humidity is 21.4 % RH, the cooling mode is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt %, the preservative concentration is 400 ppm, the pre-networking pressure is not more than 0.5 bar, the plying networking pressure is not more than 5 bar, the main networking pressure is not more than 5 bar, the first heat roller speed is not more than 3000 m / min, the godet speed is 3000-4600 m / min, the first heat roller temperature is not more than 140 DEG C, the second heat roller and the second dividing roller speed is 3000-4600 m / min, the second heat roller temperature is not more than 140 DEG C, the winding speed is 3000-4500 m / min, the first heat roller winding turns is 8.5 turns, the second heat roller winding turns is 4.5 turns;The polyester filament prepared by the method is prepared by selecting polyester terephthalate as the main component of the slice or melt, extruding into a filament through a metering pump and a corresponding cross-section spinneret plate, cooling, oiling in sequence, and using a plying networker to perform false twist composite winding on the drawn yarn prepared by a one-step process of first and second godet heat roller spinning and drawing and the pre-oriented yarn prepared without drawing, wherein the POY is not drawn, that is, the spinning speed is close to or consistent with the drawing speed, which is manifested as no drawing.

[0028] The method for preventing abnormal elongation of polyester filament breakage as described above, the production process parameters of the polyester composite filament are: cooling air pressure is 135 Pa, cooling air temperature is 450 DEG C, cooling air humidity is 21.4 % RH, the cooling mode is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt %, the preservative concentration is 400 ppm, the preservative concentration is 400 ppm, the pre-networking pressure is not more than 0.5 bar, the plying networking pressure is not more than 5 bar, the main networking pressure is not more than 5 bar, the first heat roller speed is not more than 3000 m / min, the godet speed is 3000-4600 m / min, the first heat roller temperature is not more than 140 DEG C, the second heat roller and the second dividing roller speed is 3000-4600 m / min, the second heat roller temperature is not more than 140 DEG C, the winding speed is 3000-4500 m / min, the first heat roller winding turns is 8.5 turns, the second heat roller winding turns is 4.5 turns;The polyester filament prepared by the method is prepared by selecting polyester terephthalate as the main component of the slice or melt, extruding into a filament through a metering pump and a corresponding cross-section spinneret plate, cooling, oiling in sequence, and using a plying networker to perform false twist composite winding on the drawn yarn prepared by a one-step process of first and second godet heat roller spinning and drawing and the pre-oriented yarn prepared without drawing, wherein the POY is not drawn, that is, the spinning speed is close to or consistent with the drawing speed, which is manifested as no drawing.

[0029] The production process flow of the polyester high-oriented yarn HOY is: polyester melt→spinning plate extrusion→cooling→oiling→pre-networking→godet→second heat roller heat setting→second dividing roller→main networking→winding molding;

[0030] The method for preventing abnormal elongation and breaking of polyester filament as described above, the production process parameters of the polyester high orientation yarn (HOY) are: the cooling air pressure is 135 Pa, the cooling air temperature is 450 DEG C, the cooling air humidity is 21.4% RH, the cooling mode is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt%, the preservative concentration is 400 ppm, the pre-networking pressure is not more than 0.5 bar, the main networking pressure is not more than 5 bar, the godet speed is 3000-5500 m / min, the second hot roller and the second filament dividing roller speed are 3000-5500 m / min, the second hot roller temperature is not more than 120 DEG C, the winding speed is 3000-5500 m / min, the first hot roller winding turns are 8.5 turns, and the second hot roller winding turns are 4.5 turns; the polyester filament is prepared by selecting polyethylene terephthalate as the main component of the slice or melt, extruding into a filament through a metering pump and a corresponding cross-section spinneret, and sequentially passing through a cooling, oiling, networker false twisting, and winding forming process, wherein the spinning speed is substantially equal to the drawing speed without an additional drawing step.

[0031] Beneficial effects:

[0032] (1) The method for preventing abnormal elongation and breaking of polyester filament can effectively prevent the abnormal breaking elongation and breaking strength of the polyester filament caused by the abnormal roughness of the second hot roller by regularly monitoring whether the roughness of the second hot roller is normal.

[0033] (2) The method can also know the most suitable polyester fiber variety for the production of the second hot roller by regularly monitoring the surface roughness of the second hot roller, thereby prolonging the service life of the second hot roller and avoiding the generation of abnormal filaments. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The process flow chart for preparing the polyester filament in the embodiment B1 of the present application;

[0035] Figure 2 The process flow chart for preparing the polyester composite filament in the embodiment B2 of the present application;

[0036] Figure 3 The process flow chart for preparing the polyester high orientation yarn (HOY) in the embodiment B3 of the present application;

[0037] In the figure, 1 is a spinning assembly, 2 is an oil nozzle, 3 is a pre-networking device, 6 is a first hot roller, 7 is a first filament dividing roller, 8 is a second hot roller, 9 is a second filament dividing roller, 10 is a main networking device, 11 is a polyester filament, 12 is a polyester POY filament, 13 is a polyester FDY filament, 14 is a plying networking device, 16 is a pneumatic filament dividing roller, and 17 is a godet. DETAILED DESCRIPTION

[0038] The application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims.

[0039] The test method of the relevant performance indicators in the following examples is as follows:

[0040] Elongation at break: the sample is tested for elongation at break using a YG023B-II type full-automatic single yarn strength machine. In order to ensure the accuracy of the measured data, the whole spinning position 12 spool is tested, and three sets of data are reserved for single sample testing and the average value is taken.

[0041] Example A1

[0042] A method for preventing abnormal elongation of polyester filament breakage, the production process of the polyester filament comprising a drawing setting process, in the drawing setting device, only the surface of the second hot roller contains a ceramic coating layer;

[0043] In the production process of the polyester filament, the surface roughness a* of the second hot roller is measured every 48h (when measuring, the surface roughness of the second hot roller is measured using a Japanese SJ-220 roughness detector), and the a* obtained by each measurement is the average value of 2-3 measurement values. After each measurement, it is judged whether a* is greater than a max If yes, the second hot roller is replaced with a second hot roller with a surface roughness less than a max Otherwise, no adjustment is made.

[0044] a max The calculation formula of a

[0045] a max =(1+β×d / f)×a;

[0046] In the formula, β is a coefficient corresponding to the cross-sectional type of the polyester filament; when the cross-sectional type of the polyester filament is circular, β is 1; when the cross-sectional type of the polyester filament is triangular, β is 0.9; when the cross-sectional type of the polyester filament is trilobal, β is 0.8; when the cross-sectional type of the polyester filament is hollow, β is 0.6;

[0047] f is the number of filaments in the polyester filament;

[0048] d is the numerical value of the fineness of the polyester filament in denier;

[0049] a is the average value of the surface roughness of the second hot roller measured after one month on the machine, and the measured a is the average value of 2-3 measurement values.

[0050] Example B1

[0051] A method for preparing polyester filaments, comprising the following steps:

[0052] As shown in Figure 1 , melt the bright polyester (manufacturer Jiangsu Hengli Chemical Fiber Co., Ltd., brand CZ-318G, melt intrinsic viscosity [eta] 0.6606 dL / g) after extrusion through the spinneret, and the cooled filament bundle is oiled through the oil nozzle 2 after the spinning assembly 1, the oiled filament bundle is wound after the pre-networking device 3, the first hot roller 6 stretching, the first filament splitting roller 7, the second hot roller 8 heat setting, the second filament splitting roller 9, and the main networking device 10, to obtain the polyester filaments 11; wherein the surface of the second hot roller contains a ceramic coating;

[0053] The process parameters for preparing the polyester filaments are: cooling air pressure 135 Pa, cooling air temperature 450℃, cooling air humidity 21.4% RH, cooling method side blowing cooling, cooling air speed 0.4 m / s, oil concentration 15.5 wt%, preservative concentration 400 ppm, pre-networking pressure 0.5 bar, main networking pressure 4.5 bar, first hot roller speed 2700 m / min, first filament splitting roller speed 2700 m / min, first hot roller temperature 81℃, second hot roller and second filament splitting roller speed 4785 m / min, second hot roller temperature 127℃, winding speed 4700 m / min, first hot roller winding turns 8.5 turns, and second hot roller winding turns 5.5 turns.

[0054] The final polyester filaments prepared have a specification of 55 dtex / 36 f and a fineness of 55 dtex, and the cross-sectional type is triangular.

[0055] In the actual production of polyester filaments with a specification of 55 dtex / 36 f, the GR2 hot roller shell roughness is detected, and the elongation physical properties of the product are controlled by sampling and physical property inspection, then the Hengli Chemical Fiber filament 55 dtex / 36 f product in 2023-2024 is statistically analyzed, and in the continuous spinning for one year, the number of times of abnormal yarn downgrading caused by abnormal breaking elongation in sampling and inspection is 7, and the cumulative tracking downgraded yarn cake number is 316 spindles;

[0056] Therefore, in the above method for preparing polyester filaments with a specification of 55 dtex / 36 f, the method of Example A1 is used for preparation, and in 2024-2025, the number of times of abnormal yarn downgrading caused by abnormal breaking elongation in sampling and inspection is 2 in the continuous spinning for one year, and the cumulative tracking downgraded number is 13 spindles, which indicates that the present application can significantly prevent the elongation abnormality of the whole spinning position caused by the change of the hot roller roughness, and greatly reduce the abnormal yarn downgrading caused by the untimely sampling.

[0057] Example B2

[0058] A method for preparing a polyester composite yarn, comprising the following steps:

[0059] As shown in Figure 2 , melt the semi-dull polyester (manufacturer: Jiangsu Hengli Chemical Fiber Co., Ltd., brand CZ-318H / D, semi-dull melt intrinsic viscosity [η] 0.6831 dL / g) after the spinneret extrusion, and divide it into two groups of yarn after the spinning assembly 1. The first group of yarn gets the polyester POY yarn 12 after the guide plate, and the second group of yarn gets the polyester FDY yarn 13 after the pre-networking device 3, the first hot roller 6 stretching, and the pneumatic yarn splitting roller 16, respectively. Then, the polyester POY yarn 12 and the polyester FDY yarn 13 are combined after the guide plate 17, and then the plying network device is used for plying, the second hot roller 8 is used for heat setting, and the second yarn splitting roller 9 is used for winding, to prepare the polyester composite yarn. The surface of the second hot roller contains a ceramic coating, and the mass ratio of the polyester POY yarn and the polyester FDY yarn is 44:44.

[0060] The process parameters for preparing the polyester filament are as follows: cooling air pressure is 135 Pa, cooling air temperature is 450℃, cooling air humidity is 21.4% RH, cooling method is side blowing cooling, cooling air speed is 0.33 m / s, oil concentration is 15.8 wt%, preservative concentration is 400 ppm, pre-networking pressure is 0.5 bar, plying network pressure is 1.2 bar, main network pressure is 4.6 bar, first hot roller speed is 1200 m / min, guide plate speed is 4038 m / min, first hot roller temperature is 105℃, second hot roller and second yarn splitting roller speed is 4034 m / min, second hot roller is not heated, winding speed is 4000 m / min, first hot roller winding turns is 8.5 turns, and second hot roller winding turns is 4.5 turns.

[0061] The final prepared polyester composite yarn has a specification of 88 dtex / 48 f, a fineness of 88 dtex, a cross-sectional type of circular, and an average breaking elongation of 31.4%.

[0062] In the actual production process of the polyester filament with a specification of 88 dtex / 48 f, the GR2 hot roller shell roughness is detected, and the elongation physical properties of the product are controlled by sampling and physical property inspection. Then, according to the sampling and physical property inspection, the Hengli Chemical Fiber filament 88 dtex / 48 f product in 2023-2024 is statistically analyzed. During the continuous spinning for one year, the number of times of abnormal yarn downgrading caused by abnormal breaking elongation in the sampling and inspection is 45, and the cumulative number of downgraded yarn cakes is 501 spindles.

[0063] To this end, the application is prepared in the above method of preparing polyester filaments with a specification of 88 dtex / 48 f, using the method of Example A1, 2024-2025, continuous spinning for one year, and the number of times that abnormal elongation at break leads to abnormal yarn downgrading in sampling inspection is 11, and the cumulative number of downgraded yarn cakes is 63 spindles, indicating that the application can significantly prevent elongation abnormalities at the whole spinning position caused by changes in the roughness of the hot roller, and greatly reduce the abnormal yarn downgrading caused by untimely sampling.

[0064] Example B3

[0065] A method for preparing polyester high orientation yarn (HOY), comprising the following steps:

[0066] As shown in Figure 3 , melt the semi-dull polyester (manufacturer: Jiangsu Hengli Chemical Fiber Co., Ltd., brand CZ-318H / D, semi-dull melt intrinsic viscosity [η] 0.6831 dL / g) in sequence, then extrude through the spinneret, and oil the cooled yarn bundle through the oil nozzle 2 after passing through the spinning assembly 1, then the oiled yarn bundle will pass through the pre-networking device 3, the godet 17, the second hot roller 8 heat setting, the second dividing roller 9, and the main networking device 10 in sequence, and then be wound to prepare the polyester high orientation yarn (HOY); wherein the surface of the hot roller contains a ceramic coating;

[0067] The production process parameters of the polyester high orientation yarn (HOY) are: cooling air pressure 135 Pa, cooling air temperature 450℃, cooling air humidity 21.4% RH, cooling method side blowing cooling, cooling air speed 0.33 m / s, oil concentration 15.8 wt%, preservative concentration 400 ppm, pre-networking pressure 0.5 bar, main networking pressure 3.4 bar, second hot roller and second dividing roller speed 4565 m / min, second hot roller temperature 104℃, godet speed 4563 m / min, winding speed 4550 m / min, and second hot roller winding turns 4.5 turns.

[0068] The final polyester high orientation yarn (HOY) prepared has a specification of 94 / 36, a fineness of 94, a circular cross-sectional type, and an average breaking elongation of 69.5%.

[0069] In the actual production process of polyester filaments with a specification of 94 dtex / 36 f, the GR2 hot roller shell roughness is detected, and the elongation physical properties of the product are controlled by sampling inspection, then the 2023-2024 Hengli Chemical Fiber filament 94 dtex / 36 f product is statistically analyzed, and the number of times that abnormal elongation at break leads to abnormal yarn downgrading in sampling inspection is 12 in continuous spinning for one year, and the cumulative number of downgraded yarn cakes is 154 spindles.

[0070] Therefore, the application is prepared by the method of example A1 in the above method of preparing polyester filaments with a specification of 94 dtex / 36 f, 2024-2025, continuous spinning for one year, and the number of times of abnormal yarn downgrading caused by abnormal elongation at break in sampling inspection is 0, and the cumulative number of downgraded yarns is 0 spindles, which indicates that the application can significantly prevent elongation abnormality at the whole spinning position caused by the change of the roughness of the hot roller and greatly reduce the abnormal yarn downgrading caused by untimely sampling.

Claims

1. A method for preventing abnormal elongation of polyester filament breakage, the production process of the polyester filament comprising a draw texturing process, wherein only the surface of the second heat roller in the draw texturing device contains a ceramic plating layer, characterized in that, In the production of polyester filaments, the surface roughness a* of the second heat roller is measured at intervals, and after each measurement, it is determined whether a* is greater than a max If so, the second heat roller is replaced with a second heat roller having a surface roughness less than a max ; otherwise, no adjustment is made. The time period is 48 hours; a max The calculation formula is as follows: a max = (1 + β x d / f) x a; In the formula, β is a coefficient corresponding to the cross-sectional type of the polyester filament; when the cross-sectional type of the polyester filament is circular, β is 1; when the cross-sectional type of the polyester filament is triangular, β is 0.9; when the cross-sectional type of the polyester filament is trilobal, β is 0.8; and when the cross-sectional type of the polyester filament is hollow, β is 0.6; f is the number of filaments in the polyester filament; d is the value of the fineness of the polyester filament in denier; a is the average value of the measured surface roughness of the second heating roller after spinning for one month.

2. The method of claim 1, wherein the method is characterized by, When the surface roughness a* of the second heating roller is measured at intervals, 2-3 data are obtained each time, and the average value of the data is calculated as the final result a* of the measurement.

3. The method of claim 1, wherein the method is characterized by, a is the average value of the measured surface roughness of the second heating roller after spinning for one month.

4. The method of claim 1, wherein the method is characterized by, The production process of the polyester filament is: melting → spinneret extrusion → cooling → oiling → pre-networking → first heating roller stretching → first dividing roller → second heating roller heat setting → second dividing roller → main networking → winding.

5. The method of claim 4, wherein the method is characterized by, The production process parameters of the polyester filament are: the cooling method is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt%, the pre-networking pressure is not more than 0.5 bar, the main networking pressure is not more than 5 bar, the first heating roller speed is not more than 3000 m / min, the first dividing roller speed is not more than 3000 m / min, the first heating roller temperature is not more than 140 ℃, the second heating roller and the second dividing roller speed are 3000-5500 m / min, the second heating roller temperature is not more than 140 ℃, and the winding speed is 3000-5500 m / min.

6. The method of preventing abnormal elongation of polyester filament breakage according to claim 1, wherein, The production process of the polyester high orientation yarn HOY is: The production process of the polyester high orientation yarn HOY is: polyester melt → spinneret extrusion → cooling → oiling → pre-networking → godet → second heating roller heat setting → second dividing roller → main networking → winding.

7. The method of claim 6, wherein the method is characterized by, The production process parameters of the polyester high orientation yarn HOY are: the cooling method is ring blowing cooling or side blowing cooling, the cooling air speed is not more than 0.6 m / s, the oil concentration is 10-20 wt%, the pre-networking pressure is not more than 0.5 bar, the main networking pressure is not more than 5 bar, the godet speed is 3000-5500 m / min, the second heating roller and the second dividing roller speed are 3000-5500 m / min, the second heating roller temperature is not more than 120 ℃, and the winding speed is 3000-5500 m / min.

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