Polypropylene fiber, polypropylene fiber silk roll and preparation method of silk roll

Abstract

The invention discloses a polypropylene fiber, a polypropylene fiber silk roll and a preparation method of the silk roll. The MFR of the polypropylene fiber is 10-100g / 10min, and the molecular weight distribution is less than 3.5. The weight of the polypropylene fiber yarn coil is 2.0-10.0 kg, and the shoulder rate is 0-10%; and the boiling water shrinkage difference between the inner-layer fiber and the outer-layer fiber of the silk coil is less than 1.0%. The silk roll is good in rolling posture and unwinding performance, extremely small in shrinkage difference between the inner layer and the outer layer of the silk roll, not prone to causing poor biological properties, particularly not prone to causing poor dyeing when fibers can be dyed, and suitable for being used as clothing materials.

Description

Technical Field

[0001] The present invention relates to a polypropylene fiber and a yarn roll wound from the polypropylene fiber. Specifically, it relates to a polypropylene fiber with good winding formability, small shrinkage difference and dyeing difference between the inner and outer layers of the yarn roll. Background Art

[0002] Polyolefin fibers represented by polypropylene are now mostly made into spunbond non-woven fabrics and melt-blown non-woven fabrics and applied in fields such as filtration materials, medical materials, agricultural greenhouses, and household interiors due to their excellent lightness, chemical resistance, etc. Since the polypropylene molecular chain does not contain polar functional groups or reactive groups and has a dense structure, it is difficult to dye, which limits its development in clothing applications.

[0003] To solve the above problems, researchers have carried out a large amount of improvement work. Adding pigments is a simple method for coloring polypropylene fibers, but it is difficult for pigments to stably present bright colors and the color types are not rich. For dyeing with dyes, there are roughly the following 5 methods for preparing dyeable polypropylene fibers by modification methods: fiber surface treatment method, graft copolymerization modification method (CN1530489A), composite fiber method (CN108779583A), blending metal compound modification method, and blending heterophasic polymer modification method (CN111793843A).

[0004] The high elastic deformation of the fiber refers to a phenomenon in which the fiber undergoes stress relaxation or creep and shrinks over time and temperature after high-temperature spinning. High elastic deformation generally occurs above the glass transition temperature of the fiber. When the temperature drops below the glass transition temperature, the molecular chains in the fiber stop moving and the fiber tends to a stable state. The glass transition temperature of polyester is usually between 50 and 70 °C. Therefore, after the polyester fiber is ejected from the spinneret, the molecular chains are quickly frozen at room temperature and do not shrink or only shrink slightly. The glass transition temperature of polypropylene is usually between -20 and 0 °C, far lower than room temperature. Therefore, the molecular chains in the polypropylene fiber after spinning are always in a state of free movement, showing a kind of high elastic deformation, and generally reach a stable state in 7 days under the conditions of 20 °C and 60% humidity (referred to as delayed shrinkage). This long-term high elastic recovery will cause the polypropylene fiber yarn roll to have poor winding shape after storage for a period of time, large shrinkage difference between the inner and outer layers, difficult unwinding, unstable fabric width, and especially uneven color after dyeing of the dyeable polypropylene fiber. Summary of the Invention

[0005] The purpose of the present invention is to provide a polypropylene fiber capable of forming a polypropylene fiber yarn roll with a good winding shape and a small shrinkage difference between the inner and outer layers, as well as this polypropylene fiber yarn roll and a preparation method of the yarn roll.

[0006] The technical solution of the present invention is as follows:

[0007] Polypropylene fiber, with MFR of 10 - 100 g / 10 min and molecular weight distribution below 3.5.

[0008] Preferably, the polypropylene fiber contains 3 - 15 wt% of polyester with a melting point below 220°C.

[0009] Preferably, the polyester contains aliphatic dicarboxylic acid units with the total number of carbon atoms below 8.

[0010] Preferably, the strength of the polypropylene fiber is above 3.5 cN / dtex, and the product of strength and elongation is preferably above 25.

[0011] The present invention also discloses a polypropylene filament roll formed by winding the above polypropylene fiber. The weight of the filament roll is 2.0 - 10.0 kg, and the shoulder ratio is 0 - 10%; the difference in boiling water shrinkage rate between the inner and outer layer fibers of the filament roll is below 1.0%.

[0012] Take the inner layer fiber and outer layer fiber of the filament roll, and dye them at 120°C using the same disperse dye. The difference in hue value ΔE is preferably below 2.0.

[0013] The preparation method of the polypropylene fiber filament roll is mainly to add polypropylene into the spinning box, then send it into the spinning pack through a pipe, extrude it through a spinneret, cool it, oil it, interlace it, and wind it after being shaped by roller stretching. The draw ratio during spinning is below 220, the temperature of the heat-setting roller is 125 - 155°C, and the contact length between the fiber and the heat-setting roller is above 50 cm.

[0014] Preferably, the polypropylene contains 3 - 15 wt% of polyester with a melting point below 220°C.

[0015] By adjusting the fluidity, molecular weight distribution of polypropylene and the spinning process, the present invention enables the filament roll obtained after winding and forming to have a good winding shape and unwinding property. Further, that is, the shrinkage difference between the inner and outer layers of the filament roll is extremely small, and it is not easy to produce physical property differences. Especially when dyeing the fiber, it is not easy to produce dyeing differences. It is a kind of polypropylene fiber and polypropylene fiber filament roll suitable for clothing applications.

[0016] Description of the drawings

[0017] Figure 1 It is a schematic diagram of the filament roll. Dmax represents the maximum distance between the end face of the filament roll and the end face of the paper tube, and Dmin represents the minimum distance between the end face of the filament roll and the end face of the paper tube. Detailed implementation mode

[0018] Generally, polypropylene fibers have a large rate of delayed shrinkage. During the winding process, the fibers continuously tighten, resulting in heavy bobbins that cannot be removed from the winder. Therefore, only the bobbin weight can be reduced, and frequent bobbin exchanges are required during the post-processing, leading to low productivity and high costs. At the same time, when polypropylene fibers are wound, as the winding amount increases, the phenomenon of bulging occurs at both ends of the bobbin (commonly known as shoulders). Excessive shoulders can cause the bobbin to deform or even break, resulting in unsuccessful winding; even if the bobbin shape does not break, the vibrations generated during subsequent bobbin packaging, cargo handling, and cargo transportation can also cause the bobbin to be damaged and unusable; during warping and weaving processes, the bobbin also has poor unwinding performance, leading to damage to the winding layer and disorder of the filaments, thereby causing broken filaments.

[0019] The main object of the present invention is to reduce the delayed shrinkage of polypropylene fibers, that is, to reduce the shrinkage difference of polypropylene fibers from being spun to reaching a stable state. First, in terms of the selection of the fiber-forming polymer, the present invention limits the MFR (melt flow rate) of the polypropylene fiber to 10 - 100 g / 10 min, and the molecular weight distribution is below 3.5.

[0020] The reason for selecting polypropylene fibers with an MFR in the range of 10 - 100 g / 10 min is that when the MFR of polypropylene fibers is greater than 100 g / 10 min, the pressure of the melt reaching the spinneret during spinning is small, which will cause unstable extrusion and uneven spun yarns. When the MFR of polypropylene fibers is less than 10 g / 10 min, the pressure of the spinning component is large, the service life is shortened, and the cost increases; moreover, the smaller the MFR, the longer the molecular chain of polypropylene and the more tightly entangled. Under the same spinning temperature and draw ratio conditions, the molecular chain of polypropylene with a small MFR is more likely to be oriented, resulting in more high-elastic deformation of the polypropylene fiber, ultimately causing a large delayed shrinkage, and a larger shrinkage difference and dyeing difference between the inner and outer layers of the bobbin (the inner layer refers to the last 100 g remaining on the bobbin paper tube, and the outer layer refers to the first 100 g unwound from the bobbin). The present invention more preferably has an MFR of the polypropylene fiber of 30 - 80 g / 10 min.

[0021] The molecular weight distribution of the polypropylene fiber also affects the spinning operability and the shrinkage difference between the inner and outer layers of the bobbin. When the molecular weight distribution of the polypropylene fiber is greater than 3.5, it indicates that the molecular weight distribution of polypropylene is uneven, which easily causes frequent filament breaks during spinning, unevenness in the fiber long axis direction, and a large shrinkage difference between the inner and outer layers after the formed bobbin is stably placed. In the case of dyeable polypropylene fibers, it will lead to a large color difference between the inner and outer layers. The present invention preferably has a molecular weight distribution of the polypropylene fiber below 3.0.

[0022] In addition to the above limitations on the MFR and molecular weight distribution of polypropylene fibers, the present invention also adjusts the spinning process to achieve the purpose of reducing the delayed shrinkage of polypropylene fibers.

[0023] The process of preparing polypropylene fiber is the same as the usual polypropylene spinning process. The polypropylene is first added into the spinning box and then sent into the spinning assembly through the pipe. After being spit out from the spinneret, it is cooled, oiled, entangled, stretched and shaped by rollers, and then wound to obtain a polypropylene fiber roll.

[0024] In the normal spinning process, the delayed shrinkage can be reduced by increasing the winding relaxation rate between the winder and the previous roller as much as possible (generally above 6%) to relax the internal structure of the fiber. However, this method can only reduce the delayed shrinkage to a small extent and cannot meet the needs of large-size yarn rolls.

[0025] In the process of preparing polypropylene fiber and its yarn roll, the invention reduces the delayed shrinkage of polypropylene fiber by limiting the extrusion stretching ratio during spinning, the temperature of the heat setting roller, and the contact length between the fiber and the heat setting roller.

[0026] The extrusion stretch ratio refers to the value obtained by dividing the spinning speed (i.e., the speed of the first roller contacting the fiber after it is extruded from the spinneret) by the polymer extrusion line speed. The present invention limits the extrusion stretch ratio to less than 220, otherwise the larger the extrusion stretch ratio, i.e., the larger the spinning speed or the smaller the extrusion line speed, the larger the amount of high elastic deformation will be due to excessive stretching of the fiber during the spinning process from the spinneret to the first roller, which will cause delayed shrinkage of the silk roll, a large difference in shrinkage between the inner and outer fibers, and reduced quality of the silk roll, which is easy to cause poor dyeing in the case of dyeable polypropylene fibers.

[0027] The temperature of the heat-setting roller is 125-155°C. Depending on the spinning process and equipment, one heat-setting roller or multiple heat-setting rollers can be set during the spinning process. When multiple heat-setting rollers are set, the heat-setting roller temperature here refers to the temperature of all rollers with heat-setting functions. When the temperature of the heat-setting roller is less than 125°C, the fiber will not be fully set, the delayed shrinkage will be large, and the yarn roll will have a poor winding posture and a large difference in shrinkage between the inner and outer layers. When the temperature of the heat-setting roller is greater than 155°C, although the fiber is thoroughly set and the delayed shrinkage is suppressed, since this temperature is close to the melting point of polypropylene, the mechanical properties of the fiber will be greatly reduced.

[0028] The contact length between the fiber and the heat setting roller of the present invention is more than 50 cm. The contact length refers to the contact length between the fiber and all the heat setting rollers at any time point in the spinning process, which is mainly controlled by the number of heat setting rollers and the number of turns of the fiber on the heat setting roller. When the contact length between the fiber and the heat setting roller is less than 50 cm, the fiber cannot be fully set, the delayed shrinkage is large, and the winding posture of the yarn roll is poor and the shrinkage difference between the inner and outer layers is large.

[0029] The above three process conditions defined in the present invention must all be met. Lack of any one of them will result in the delayed shrinkage of the fiber not being suppressed. At the same time, through the synergistic effect of the above three process conditions and the MFR and molecular weight distribution of the polypropylene fiber, when the weight of the obtained polypropylene fiber roll is 2.0-10.0 kg, the shoulder rate of the roll is 0-10%, and the difference in boiling water shrinkage between the inner and outer layer fibers is less than 1.0%.

[0030] Controlling the weight of the polypropylene fiber roll within the range of 2.0 to 10.0 kg can reduce the frequency of paper tube replacement during fiber manufacturing, and the roll does not need to be frequently replaced during post-processing, thereby improving productivity and reducing costs. Controlling the shoulder rate of the polypropylene fiber roll within the range of 0 to 10% can effectively solve the problem of roll breakage during the winding process, and the roll will not be damaged during packaging, transportation, etc., and the post-processing process can also proceed smoothly.

[0031] The difference in boiling water shrinkage between the inner and outer fibers of the polypropylene filament roll of the present invention is less than 1%, indicating that the difference in shrinkage characteristics between the inner and outer layers of the fiber is extremely small, the width of the fabric obtained is stable, and the occurrence of dyeing differences can be well suppressed in the case of dyeable polypropylene fibers.

[0032] Based on the requirement of color diversity for clothing use, the present invention preferably contains dyeable polyester in the polypropylene fiber. When the content of the polyester in the polypropylene fiber is too low, it cannot provide enough color-developing units to make the polypropylene fiber bright in color after dyeing; if the content of the polyester is too high, although it can bring higher dye exhaustion rate and color-developing performance, too much polyester will destroy the continuity of the crystallization of the polypropylene molecule, affect the mechanical properties of the fiber, and weaken the secondary bond force between the molecular bonds, causing the fiber to easily produce shrinkage differences, resulting in poor dyeing when the polypropylene fiber is stored in the form of a silk roll and then spun and dyed. The present invention preferably contains 3 to 15 wt% of the polyester in the polypropylene fiber.

[0033] Since the melting point of polypropylene is relatively low and the melting point of polyester is relatively high, the spinning temperature needs to be slightly higher than the melting point of polyester when the two are blended and spun. Among high molecular polymers, the melting point of polypropylene is not high. When the spinning temperature is higher than the melting point of polypropylene, polypropylene will crack. The higher the spinning temperature, the more serious the cracking. When blended with polyester, the spinning temperature needs to be higher than the melting point of the higher melting point polyester. Therefore, if the melting point of the selected polyester is too high, it will cause severe thermal cracking of polypropylene, frequent fiber breakage during spinning, and affect the mechanical properties of the final fiber. The melting point of the polyester described in the present invention is preferably below 220°C, more preferably below 200°C.

[0034] In order to obtain polypropylene fibers with bright and deep colors, the polyester with low refractive index and high color rendering property preferably contains aliphatic dicarboxylic acid units with a total carbon atom number of 8 or less and a content of 5 mol% or more based on all dicarboxylic acid components of the copolyester, thereby reducing the refractive index of the polyester and improving the color rendering property. The aliphatic dicarboxylic acid units can be malonic acid units, fumaric acid units, maleic acid units, succinic acid units, itaconic acid units, pimelic acid units, adipic acid units, cyclohexanedicarboxylic acid units, etc. The aforesaid aliphatic dicarboxylic acid unit components can contain only one kind, or can contain multiple kinds simultaneously. When the copolymerization rate of the aliphatic dicarboxylic acid units is 5 mol% or more, bright and deep color rendering can be achieved, so it is preferred. In addition, in order to obtain polypropylene fibers with high shrinkage performance or cationic dye-dyeable properties, isophthalic acid, phthalic acid, sodium isophthalate-5-sulfonate, etc. can also be used in combination.

[0035] The blending method and result of polypropylene and polyester in the present invention are not particularly limited, and it is only necessary to meet the requirements of conventional spinning. Of course, in order to increase the interfacial specific surface area of the polypropylene and polyester components, improve the dye exhaustion rate, and enable the polypropylene fibers to obtain deeper colors after dyeing, the blending intensity can be increased through a mixing device to make the average dispersion diameter of the polyester in the polypropylene fibers as small as possible, such as the average dispersion diameter being 500 nm or less.

[0036] In the preferred technical solution of the dyeable polypropylene fibers and their yarn packages added with polyester, since the difference in boiling water shrinkage between the inner and outer layers of the yarn package can be controlled within 1%, the hue value difference ΔE after dyeing the inner and outer layer fibers of the yarn package with the same disperse dye at 120 °C is preferably 2.0 or less.

[0037] The strength of the polypropylene fibers described in the present invention is preferably 3.5 cN / dtex or more, and the product of strength and elongation is preferably 25 or more. Generally, in order to increase the fiber strength, the draw ratio is increased in the manufacturing process. However, in this case, the elongation of the fibers will inevitably decrease, and it is easy to generate hairiness in post-processing, affecting the weaving passability, etc. Therefore, in order to obtain excellent elongation and strength, it is preferred to control the product of strength and elongation of the fibers to be 25 or more.

[0038] The polypropylene fibers and polypropylene fiber yarn packages obtained by the present invention through selecting polypropylene with specific MFR and molecular weight distribution under certain process conditions have a small difference in boiling water shrinkage rate and dyeing difference between the inner and outer layers. After post-processing such as dyeing of fiber structures formed by the polypropylene fiber yarn packages, such as woven fabrics and knitted fabrics, the fabric is flat and has no obvious color difference.

[0039] The test methods involved in the present invention are as follows:

[0040] (1) MFR

[0041] The test is carried out according to the standard ASTM D1238 using a melt flow rate instrument. The fiber sample is placed in the measuring tank, and under the load condition of 230 °C and 2.16 kg, the mass of the fiber melted and extruded within 10 minutes is measured. If the test time is less than 10 minutes, it is converted according to the extruded mass and the actual extrusion time to obtain the MFR (g / 10 min). Ten samples are taken for testing respectively, and the final result is the average value.

[0042] (2) Molecular weight distribution

[0043] The fiber sample is dissolved in trichlorobenzene, and the molecular weight distribution PD is measured by a gel permeation chromatograph (GPC) (Waters 2690 produced by Waters). Three samples are taken for testing respectively, and the final result is the average value.

[0044] (3) Melting point

[0045] The melting peak temperature is measured using a differential scanning calorimeter (DSC-7 produced by Perkin Elmer). Under a nitrogen atmosphere, about 5 mg of the fiber sample is heated from 0 °C to 280 °C at a heating rate of 16 °C / min, and then held at 280 °C for 5 minutes to eliminate the thermal history of the sample. Then, it is quenched from 280 °C to 0 °C and then heated from 0 °C to 280 °C again at a heating rate of 16 °C / min. The melting peak temperature is calculated from the melting peak observed during the second heating process. Specifically, when the polyester component and polypropylene show split peaks, the melting peak temperature is calculated by selecting the other melting peak according to the known melting point of polypropylene; if only one peak appears, it indicates that the melting points of the polyester component and polypropylene are similar, and the temperature calculated from the peak can be regarded as the melting point of the polyester. Three samples are taken for testing respectively, and the final result is the average value.

[0046] (4) Strength, elongation, and product of strength and elongation

[0047] The coiled fiber is used as the sample, and the test is carried out according to the national standard GB14344 under the environment of 20 °C and 65% RH humidity. The strength is the stress / fineness (cN / dtex) at the maximum breaking point during the fiber stress-strain tension, the elongation is the strain (%) at the maximum breaking point of the fiber, and the product of strength and elongation is strength × elongation 1 / 2 , and ten samples are taken for testing respectively, and the final result is the average value.

[0048] (5) Coiled weight, shoulder rate

[0049] Take the coiled fiber filament coil, as Figure 1 shown, measure the maximum distance (Dmax) and the minimum distance (Dmin) between the outer end face of the coiled filament and the end face of the paper tube, then the shoulder rate is [(Dmax - Dmin) / Dmin] × 100%. The coiled weight is the weight of the fiber wound on the paper tube.

[0050] (6) Boiling water shrinkage rate difference between the inner and outer layers of fibers

[0051] Take a fiber filament roll. In the outermost 100 g fiber sample (the first 100 g part removed from the filament roll), use a skein winder to take 10 m of fiber as the measurement object, and measure the initial length L1 under a load of 0.05 g / d; remove the load, put the fiber into a net bag in a free state, boil it in a 98 °C water bath for 30 min, air-dry it naturally for 24 h under the condition of 20 °C × 65% RH, and measure the initial length L2 under a load of 0.05 g / d. The boiling water shrinkage rate of the outer layer of fibers is [(L1 - L2) / L1] × 100%.

[0052] Take the innermost 100 g fiber sample of the above filament roll (the last 100 g part remaining on the filament roll paper tube), repeat the above steps to obtain the boiling water shrinkage rate of the inner layer of fibers. Then the boiling water shrinkage rate difference between the inner and outer layers of fibers is ∣outer layer fiber shrinkage rate - inner layer fiber shrinkage rate∣. Take 10 samples for testing respectively, and the final result is the average value.

[0053] (7) Hue value difference ΔE

[0054] Take 100 g (sample A) of fibers from the outermost layer (the first part removed from the filament roll) and 100 g (sample B) of fibers from the innermost layer (the last part remaining on the filament roll paper tube) of the fiber filament roll to make tubular knitted fabrics respectively. Prepare a dye solution (mix 2 g / L leveling agent and 2 g / L polyester dyeing acid evenly with soft water to form an auxiliary solution. Secondly, according to the weight of the tubular knitted fabric, add 3.0 owf% black disperse dye to the auxiliary solution and stir evenly to form a dye solution), then put the refined knitted fabric and the dye solution into a dyeing machine according to a bath ratio of 1:30, and keep it at 120 °C for 45 minutes. Then mix 0.5 g / L sodium dithionite reducing agent evenly with soft water, put it into the dyeing machine together with the dyed knitted fabric, and keep it at 80 °C for 20 minutes to reduce and wash the floating color, and then complete the dyeing.

[0055] According to the L*, a*, b* color system specified by CIE1976, measure the hue L*, a*, b* values of sample A and sample B in the dry and wet states, then the color difference ΔE = (ΔL* 2 +Δa* 2 +Δb* 2 ) 1 / 2 . The final result is the average value of 3 tests.

[0056] The L* value of the said polypropylene fiber refers to the average value of the L* values of sample A and sample B.

[0057] (8) Spinnability

[0058] Spinnability refers to the number of filament breaks occurring within 12 hours during the spinning process. The fewer the number of filament breaks, the better the spinning stability; the more the number of filament breaks, the worse the spinning stability. If there are no filament breaks within 12 hours, it is judged as excellent and marked with ○; if there is 1 filament break within 12 hours, it is judged as good and marked with △; if there are 2 or more filament breaks within 12 hours, it is judged as poor and marked with ×.

[0059] (9) High-speed unwinding property

[0060] Place the silk bobbin horizontally, and set a ceramic wire guide with an inner diameter of 3 mm at a distance of 45 cm from the center of gravity of the silk bobbin on the extension line of the silk bobbin shaft, and unwind at a speed of 1000 m / min for 30 minutes. Evaluate the tension variation and unwinding stability (such as filament breakage, snagging, etc.) during the unwinding process. There are 3 evaluation criteria (×: there is more than 1 filament break or 2 or more snags occur, △: no filament break occurs and there is 1 or less snag, ○: no filament break occurs and no snag occurs).

[0061] Next, the advantages of the present invention will be described in detail with reference to the listed examples and comparative examples. The present invention is not limited to the following examples.

[0062] Example 1:

[0063] Add 100 parts of polypropylene chips to the spinning box, feed them into the spinning pack through a pipe, extrude through a spinneret, then cool, oil, interlace, draw and shape, and wind up to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 5%, and excellent high-speed unwinding property; among them, the extrusion draw ratio is 102, the temperature of the heat setting roller is 145 °C, the contact length of the filament with the heat setting roller is 65 cm, and the spinnability is excellent. The MFR of the obtained fiber is 60 g / 10 min, the molecular weight distribution is 2.6, the strength is 4.3 cN / dtex, the product of strength and elongation is 37, and the difference in boiling water shrinkage rate between the inner and outer layers of the bobbin is 0.5%. After dyeing, the L* value is 91 and the hue value difference ΔE is 0.5.

[0064] Example 2:

[0065] Add 100 parts of polypropylene chips to the spinning box, feed them into the spinning pack through a pipe, extrude through a spinneret, then cool, oil, interlace, draw and shape, and wind up to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 8%, and good high-speed unwinding property; among them, the extrusion draw ratio is 102, the temperature of the heat setting roller is 145 °C, the contact length of the filament with the heat setting roller is 65 cm, and the spinnability is good. The MFR of the obtained fiber is 10 g / 10 min, the molecular weight distribution is 3.5, the strength is 4.2 cN / dtex, the product of strength and elongation is 33, and the difference in boiling water shrinkage rate between the inner and outer layers of the bobbin is 0.9%, and after dyeing, the L* value is 91 and the hue value difference ΔE is 0.5.

[0066] Example 3:

[0067] 100 parts of polypropylene chips are added to the spinning box, fed into the spinning pack through pipes, extruded through a spinneret, cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 6%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is good. The obtained fiber has an MFR of 100 g / 10 min, a molecular weight distribution of 2.7, a strength of 3.8 cN / dtex, a tenacity-elongation product of 33, a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.7%, an L* value of 91 after dyeing, and a hue difference value ΔE of 0.5.

[0068] Example 4:

[0069] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through pipes with a mixing function. After being extruded through a spinneret, they are cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 6%, and excellent high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is excellent. The obtained fiber has an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.8 cN / dtex, a tenacity-elongation product of 32, a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.6%, and the melting point of the polyester component is 178 °C. The L* value after dyeing is 24, and the hue difference value ΔE is 1.3.

[0070] Example 5:

[0071] 85 parts of polypropylene chips and 15 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through pipes with a mixing function. After being extruded through a spinneret, they are cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 8%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is excellent. The obtained fiber has an MFR of 51 g / 10 min, a molecular weight distribution of 3.1, a strength of 3.6 cN / dtex, a tenacity-elongation product of 28, a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.0%, and the melting point of the polyester component is 183 °C. The L* value after dyeing is 19, and the hue difference value ΔE is 1.9.

[0072] Example 6:

[0073] 97 parts of polypropylene chips and 3 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through a spinneret, they were cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 5%, and excellent high-speed unwinding performance. Among them, the extrusion draw ratio was 102, the temperature of the heat setting roller was 145 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was excellent. The obtained fiber had an MFR of 58 g / 10 min, a molecular weight distribution of 2.7, a strength of 4.2 cN / dtex, a tenacity-elongation product of 36, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.6%. Among them, the melting point of the polyester component was 171 °C. After dyeing, the L* value was 41 and the hue value difference ΔE was 1.3.

[0074] Example 7:

[0075] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through a spinneret, they were cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 8%, and good high-speed unwinding performance. Among them, the extrusion draw ratio was 220, the temperature of the heat setting roller was 145 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was excellent. The obtained fiber had an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.8 cN / dtex, a tenacity-elongation product of 31, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.0%. Among them, the melting point of the polyester component was 178 °C. After dyeing, the L* value was 24 and the hue value difference ΔE was 1.8.

[0076] Example 8:

[0077] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through a spinneret, they were cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 4%, and excellent high-speed unwinding performance. Among them, the extrusion draw ratio was 102, the temperature of the heat setting roller was 155 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was excellent. The obtained fiber had an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.5 cN / dtex, a tenacity-elongation product of 25, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.4%. Among them, the melting point of the polyester component was 178 °C. After dyeing, the L* value was 25 and the hue value difference ΔE was 1.3.

[0078] Example 9:

[0079] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded from the spinneret, it is cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 9%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 125 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is excellent. The obtained fiber has an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.8 cN / dtex, a strength-elongation product of 30, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.0%. The melting point of the polyester component is 178 °C. After dyeing, the L* value is 23 and the hue value difference ΔE is 1.7.

[0080] Example 10:

[0081] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded from the spinneret, it is cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 8%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 50 cm, and the spinnability is excellent. The obtained fiber has an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.8 cN / dtex, a strength-elongation product of 29, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.0%. The melting point of the polyester component is 178 °C. After dyeing, the L* value is 23 and the hue value difference ΔE is 1.7.

[0082] Example 11:

[0083] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded from the spinneret, it is cooled, oiled, texturized, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 10.0 kg, a shoulder ratio of 10%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is excellent. The obtained fiber has an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.8 cN / dtex, a strength-elongation product of 32, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.8%. The melting point of the polyester component is 178 °C. After dyeing, the L* value is 24 and the hue value difference ΔE is 1.6.

[0084] Example 12:

[0085] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with adipic acid / isophthalic acid were added to the spinning box through a mixing device, then fed into the spinning pack through a pipe with a mixing function, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 6%, and excellent high-speed unwinding performance. The extrusion draw ratio was 102, the temperature of the heat setting roller was 145 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was excellent. The MFR of the obtained fiber was 52 g / 10 min, the molecular weight distribution was 3.0, the strength was 3.7 cN / dtex, the product of strength and elongation was 31, the difference in boiling water shrinkage rate between the inner and outer layers of the bobbin was 0.6%, and the melting point of the polyester component was 189 °C. After dyeing, the L* value was 23 and the hue value difference ΔE was 1.3.

[0086] Example 13:

[0087] 90 parts of polypropylene chips and 10 parts of PET polyester chips were added to the spinning box through a mixing device, then fed into the spinning pack through a pipe with a mixing function, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 8%, and good high-speed unwinding performance. The extrusion draw ratio was 102, the temperature of the heat setting roller was 145 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was excellent. The MFR of the obtained fiber was 43 g / 10 min, the molecular weight distribution was 3.3, the strength was 3.6 cN / dtex, the product of strength and elongation was 26, the difference in boiling water shrinkage rate between the inner and outer layers of the bobbin was 0.9%, and the melting point of the polyester component was 220 °C. After dyeing, the L* value was 35 and the hue value difference ΔE was 1.8.

[0088] Example 14:

[0089] 90 parts of polypropylene chips and 10 parts of PET polyester chips were added to the spinning box through a mixing device, then fed into the spinning pack through a pipe with a mixing function, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder ratio of 10%, and good high-speed unwinding performance. The extrusion draw ratio was 102, the temperature of the heat setting roller was 145 °C, the contact length between the filament and the heat setting roller was 65 cm, and the spinnability was good. The MFR of the obtained fiber was 35 g / 10 min, the molecular weight distribution was 3.4, the strength was 3.5 cN / dtex, the product of strength and elongation was 25, the difference in boiling water shrinkage rate between the inner and outer layers of the bobbin was 1.0%, and the melting point of the polyester component was 228 °C. After dyeing, the L* value was 36 and the hue value difference ΔE was 2.0.

[0090] Example 15:

[0091] 99 parts of polypropylene chips and 1 part of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through the spinneret, it is cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 5%, and excellent high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is excellent. The obtained fiber has an MFR of 58 g / 10 min, a molecular weight distribution of 2.7, a strength of 4.2 cN / dtex, a tenacity-elongation product of 36, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 0.6%. The melting point of the polyester component is 171 °C. After dyeing, the L* value is 55 and the hue difference value ΔE is 1.1.

[0092] Example 16:

[0093] 82 parts of polypropylene chips and 18 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through the spinneret, it is cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 8%, and good high-speed unwinding performance. The extrusion draw ratio is 102, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is good. The obtained fiber has an MFR of 50 g / 10 min, a molecular weight distribution of 3.2, a strength of 3.5 cN / dtex, a tenacity-elongation product of 26, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.0%. The melting point of the polyester component is 183 °C. After dyeing, the L* value is 19 and the hue difference value ΔE is 2.0.

[0094] Comparative Example 1:

[0095] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid are added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through the spinneret, it is cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber bobbin with a weight of 6.0 kg, a shoulder rate of 11%, and poor high-speed unwinding performance. The extrusion draw ratio is 286, the temperature of the heat-setting roller is 145 °C, the contact length between the filament and the heat-setting roller is 65 cm, and the spinnability is good. The obtained fiber has an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.7 cN / dtex, a tenacity-elongation product of 31, and a difference in boiling water shrinkage rate between the inner and outer layers of the bobbin of 1.2%. The melting point of the polyester component is 178 °C. After dyeing, the L* value is 24 and the hue difference value ΔE is 2.3.

[0096] Due to the excessive extrusion draw ratio during spinning, the bobbin has a large shoulder rate, a large difference in boiling water shrinkage rate between the inner and outer layers, a large color difference after dyeing, and it is difficult to unwind at high speed.

[0097] Comparative Example 2:

[0098] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, then fed into the spinning pack through a pipe with a mixing function, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and wound to obtain a polypropylene fiber yarn roll with a weight of 6.0 kg, a shoulder ratio of 12%, and poor high-speed unwinding performance; the extrusion draw ratio was 102, the temperature of the heat setting roller was 115 °C, the contact length between the yarn and the heat setting roller was 65 cm, and the spinnability was good. The MFR of the obtained fiber was 54 g / 10 min, the molecular weight distribution was 2.8, the strength was 3.8 cN / dtex, the product of strength and elongation was 32, the difference in boiling water shrinkage rate between the inner and outer layers of the yarn roll was 1.4%, and the melting point of the polyester component was 178 °C. The L* value after dyeing was 24, and the hue value difference ΔE was 2.2.

[0099] Due to the too low temperature of the heat setting roller, the shoulder ratio of the yarn roll is large, the difference in boiling water shrinkage rate between the inner and outer layers is large, the color difference after dyeing is large, and high-speed unwinding is difficult.

[0100] Comparative Example 3:

[0101] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, then fed into the spinning pack through a pipe with a mixing function, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and wound to obtain a polypropylene fiber yarn roll with a weight of 6.0 kg, a shoulder ratio of 5%, and good high-speed unwinding performance; the extrusion draw ratio was 102, the temperature of the heat setting roller was 160 °C, the contact length between the yarn and the heat setting roller was 65 cm, and the spinnability was good. The MFR of the obtained fiber was 54 g / 10 min, the molecular weight distribution was 2.8, the strength was 3.1 cN / dtex, the product of strength and elongation was 23, the difference in boiling water shrinkage rate between the inner and outer layers of the yarn roll was 0.6%, and the melting point of the polyester component was 178 °C. The L* value after dyeing was 24, and the hue value difference ΔE was 1.3.

[0102] Due to the too high temperature of the heat setting roller, the strength and the product of strength and elongation of the fiber are small, and the physical properties are poor.

[0103] Comparative Example 4:

[0104] 90 parts of polypropylene chips and 10 parts of copolyester chips modified with cyclohexanedicarboxylic acid were added to the spinning box through a mixing device, and then fed into the spinning pack through a pipe with a mixing function. After being extruded through the spinneret, it was cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber yarn cake with a weight of 6.0 kg, a shoulder ratio of 12%, and poor high-speed unwinding performance. Among them, the extrusion draw ratio was 102, the temperature of the heat-setting roller was 145 °C, the contact length between the yarn and the heat-setting roller was 36 cm, and the spinnability was good. The obtained fiber had an MFR of 54 g / 10 min, a molecular weight distribution of 2.8, a strength of 3.9 cN / dtex, a tenacity-elongation product of 31, and a difference in boiling water shrinkage rate between the inner and outer layers of the yarn cake of 1.3%. Among them, the melting point of the polyester component was 178 °C. The L* value after dyeing was 24, and the hue value difference ΔE was 2.3.

[0105] Due to the too short contact length between the fiber and the heat-setting roller, the yarn cake had a large shoulder ratio, a large difference in boiling water shrinkage rate between the inner and outer layers, a large color difference after dyeing, and difficulty in high-speed unwinding.

[0106] Comparative Example 5:

[0107] 100 parts of polypropylene chips were added to the spinning box, fed into the spinning pack through a pipe, extruded through the spinneret, cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber yarn cake with a weight of 1.5 kg, a shoulder ratio of 4%, and poor high-speed unwinding performance. Among them, the extrusion draw ratio was 102, the temperature of the heat-setting roller was 145 °C, the contact length between the yarn and the heat-setting roller was 65 cm, and the spinnability was poor. The obtained fiber had an MFR of 12 g / 10 min, a molecular weight distribution of 4.1, a strength of 4.3 cN / dtex, a tenacity-elongation product of 32, and a difference in boiling water shrinkage rate between the inner and outer layers of the yarn cake of 1.7%. The L* value after dyeing was 92, and the hue value difference ΔE was 0.5.

[0108] Since the molecular weight distribution of the fiber was greater than 3.5, it was easy to break the yarn during spinning, and the spinnability was poor. At the same time, even when a 1.5 kg yarn cake was made, the difference in boiling water shrinkage rate between the inner and outer layers of the yarn cake was relatively large, and high-speed unwinding was difficult.

[0109] Comparative Example 6:

[0110] 100 parts of polypropylene chips were added to the spinning box, fed into the spinning pack through a pipe, extruded through the spinneret, cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber yarn cake with a weight of 6.0 kg, a shoulder ratio of 15%, and poor high-speed unwinding performance. Among them, the extrusion draw ratio was 102, the temperature of the heat-setting roller was 145 °C, the contact length between the yarn and the heat-setting roller was 65 cm, and the spinnability was good. The obtained fiber had an MFR of 5 g / 10 min, a molecular weight distribution of 3.2, a strength of 4.2 cN / dtex, a tenacity-elongation product of 33, and a difference in boiling water shrinkage rate between the inner and outer layers of the yarn cake of 1.9%. The L* value after dyeing was 91, and the hue value difference ΔE was 0.5.

[0111] Since the MFR of the fiber is less than 10 g / 10 min, the high elastic deformation during the spinning process is large, resulting in serious convex shoulders of the yarn cake, difficult high-speed unwinding, and a relatively large difference in the boiling water shrinkage rate between the inner and outer layers of the yarn cake.

[0112] Comparative Example 7:

[0113] 100 parts of polypropylene chips were added to the spinning box, fed into the spinning pack through a pipeline, extruded through a spinneret, cooled, oiled, interlaced, drawn and shaped, and then wound to obtain a polypropylene fiber yarn cake with a weight of 1.5 kg, a convex shoulder rate of 2%, and poor high-speed unwinding performance; the extrusion draw ratio was 102, the temperature of the heat-setting roller was 145 °C, the contact length between the yarn and the heat-setting roller was 65 cm, and the spinnability was poor. The MFR of the obtained fiber was 140 g / 10 min, the molecular weight distribution was 2.8, the strength was 3.7 cN / dtex, the product of strength and elongation was 34, the difference in the boiling water shrinkage rate between the inner and outer layers of the yarn cake was 1.1%, the L* value after dyeing was 91, and the color difference value ΔE was 0.5.

[0114] Since the MFR of the fiber is greater than 100 g / 10 min, it is easy to break the filament during spinning, and the spinnability is poor. At the same time, even if a 1.5 kg yarn cake is made, the difference in the boiling water shrinkage rate between the inner and outer layers of the yarn cake is relatively large, and high-speed unwinding is difficult.

[0115]

[0116]

[0117]

Claims

1. Polypropylene fiber, characterized in that: The MFR of the polypropylene fiber is 10 to 100 g / 10 min, and the molecular weight distribution is below 3.

5.

2. The polypropylene fiber according to claim 1, wherein: The polypropylene fiber contains 3 to 15 wt% of polyester with a melting point below 220 °C.

3. The polypropylene fiber according to claim 2, wherein: The polyester contains aliphatic dicarboxylic acid units with a total carbon atom number of 8 or less.

4. The polypropylene fiber according to claim 1, characterized in that: The strength of the polypropylene fiber is 3.5 cN / dtex or more, and the strength-elongation product is 25 or more.

5. A polypropylene fiber filament roll, wound from the polypropylene fiber roll according to any one of claims 1 to 4, characterized in that: The weight of the yarn cake is 2.0 to 10.0 kg, and the shoulder ratio is 0 to 10%; the difference in the boiling water shrinkage rate between the inner and outer layer fibers of the yarn cake is 1.0% or less.

6. The polypropylene fiber yarn roll according to claim 5, wherein: Take the inner layer fibers and outer layer fibers of the yarn cake and dye them at 120 °C using the same disperse dye, and the hue value difference ΔE is 2.0 or less.

7. The preparation method of the polypropylene fiber yarn roll described in claim 5 mainly involves adding polypropylene into the spinning box and then feeding it into the spinning component through a pipe. After being extruded from the spinneret plate, it is cooled, oiled, interlaced, and then drawn and shaped by rollers and wound to obtain the polypropylene fiber yarn roll; it is characterized in that: The extrusion draw ratio during spinning is 220 or less, the temperature of the heat setting roller is 125 to 155 °C, and the contact length between the fiber and the heat setting roller is 50 cm or more.

8. The preparation method of the polypropylene fiber yarn roll according to claim 7, characterized in that: The polypropylene contains 3 to 15 wt% of polyester with a melting point below 220 °C.

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