An easily dyed and wear-resistant polypropylene fiber and its preparation method

Abstract

The present application discloses an easily dyeable and wear-resistant polypropylene fiber and a preparation method thereof. The raw materials of the polypropylene fiber comprise polypropylene and amino-modified polypropylene with a mass ratio of 100:10 to 20. The amino-modified polypropylene is obtained by reacting maleic anhydride grafted polypropylene as a precursor with polyethyleneimine, and the mass ratio of maleic anhydride grafted polypropylene to polyethyleneimine is 10:0.8 to 1.3. The polypropylene fiber is prepared by melt spinning, cooling, oiling, drawing, crimping, and heat setting. The oiling is carried out using a diluted oil emulsion, and the diluted oil emulsion contains 1 to 3 wt% of a water-soluble metal salt. The water-soluble metal salt is selected from zinc salts or copper salts. The present application can improve the dyeing performance of the polypropylene fiber while maintaining its good strength performance and wear resistance.

Description

Technical Field

[0001] This application relates to the field of polypropylene fiber manufacturing, and particularly to an easily dyeable and wear-resistant polypropylene fiber and its preparation method. Background Art

[0002] Due to its light weight, chemical corrosion resistance, and excellent water repellency, polypropylene fiber is widely used in indoor decoration materials (such as carpets, automotive interiors, sofa mattress spring packs), industrial protective nets, ropes, and medical non-woven fabrics. Its molecular chain consists of a non-polar hydrocarbon structure, with high crystallinity and weak intermolecular forces. Although this characteristic endows polypropylene with good hydrophobicity and chemical stability, it results in significantly inferior dyeing performance compared to natural fibers such as cotton and silk, as well as polar synthetic fibers such as polyester and nylon. This ultimately leads to problems such as low color fastness and dull color, severely limiting the application of polypropylene in high-value-added textiles.

[0003] To improve the dyeing performance of polypropylene, existing technologies mainly introduce polar resins as "dyeing seats" and utilize the interaction between their polar groups and dye molecules to enhance the dyeing efficiency. For example, the Chinese patent with the publication number CN1464082A proposes a method for manufacturing dyeable polypropylene. By blending and spinning polyester (such as polyethylene terephthalate) with polypropylene, the dye adsorption ability is enhanced by means of polar groups such as ester groups in the polyester. However, the molecular structures of polypropylene and polyester are significantly different, and their compatibility is poor. Macroscopic phase separation is prone to occur during the melt blending process, resulting in weak interfacial bonding force inside the fiber. This defect not only reduces the breaking strength and wear resistance of the fiber but also causes interfacial peeling due to stress concentration during subsequent processing or use, exacerbating problems such as fiber fuzzing and breaking. Other methods for improving dyeing include surface modification of polypropylene (such as corona treatment, plasma treatment) or coating with a treatment agent containing polar functional groups. However, these methods have limitations such as non-persistent treatment effects, complex processes, or high costs, and are difficult to meet the requirements of industrial production. Summary of the Invention

[0004] This application provides an easily dyeable and wear-resistant polypropylene fiber and its preparation method, which can maintain good strength and wear resistance of the fiber while improving the dyeing performance of the polypropylene fiber.

[0005] In the first aspect, this application provides an easily dyeable and wear-resistant polypropylene fiber, the raw materials of which include polypropylene and amino-modified polypropylene with a mass ratio of 100:10 - 20. The amino-modified polypropylene is obtained by reacting maleic anhydride grafted polypropylene as a precursor with polyethyleneimine, and the mass ratio of maleic anhydride grafted polypropylene to polyethyleneimine is 10:0.8 - 1.3.

[0006] In any of the above technical solutions, the grafting rate of the maleic anhydride grafted polypropylene is 1 - 2%.

[0007] In any of the above technical solutions, the molecular weight of the polyethyleneimine is 800 to 2000.

[0008] In any of the above technical solutions, the reaction temperature is 180 to 210 °C.

[0009] In any of the above technical solutions, the method for preparing the amino-modified polypropylene is as follows: adding maleic anhydride grafted polypropylene and polyethyleneimine into a twin-screw extruder, melt-blending, kneading for 5 to 10 min, and extruding and pelletizing to obtain the product.

[0010] In this application, by introducing amino-modified polypropylene (PP-NH2) into the polypropylene matrix, and utilizing strong interactions such as hydrogen bonds, ion coordination, and electrostatic interactions between the amino groups (-NH2) on its molecular chain and dye molecules, the dyeing performance of the fiber is significantly improved. The polar property of the amino group breaks the chemical inertness of the non-polar molecular chain of polypropylene, providing stable binding sites for dyes, and increasing the dye uptake rate of acid or reactive dyes to more than twice that of traditional polypropylene fibers. At the same time, the amino-modified polypropylene is generated by a melt reaction of maleic anhydride grafted polypropylene (PP-g-MAH) with polyethyleneimine (PEI) having a high amino density. Its molecular chain contains both a polypropylene main chain and a polar side chain, ensuring compatibility with the matrix polypropylene. Compared with the scheme of introducing polyester in the prior art, the amino-modified polypropylene has a higher molecular structure similarity with the polypropylene matrix, improving the interfacial bonding strength during melt blending, effectively avoiding problems such as a decrease in fiber strength caused by phase separation and wear and fuzzing caused by interfacial peeling.

[0011] It should be noted that, compared with small molecule polyamine compounds such as polyethylenepolyamine, polyethyleneimine has a higher amino density and reaction activity, which is beneficial to introducing more amino dyeing sites at a low addition amount, ensuring the balance between the dyeability and mechanical properties of polypropylene. It is preferably to select polyethyleneimine with a molecular weight of 800 to 1000 to further improve the reaction efficiency and help increase the amino content in polypropylene fibers.

[0012] In any of the above technical solutions, the polypropylene fiber is prepared by melt spinning, cooling, oiling, drawing, crimping, and heat setting. The oiling uses a diluted oil emulsion, and the diluted oil emulsion contains 1 to 3 wt% of a water-soluble metal salt.

[0013] In any of the above technical solutions, the water-soluble metal salt is selected from zinc salts or copper salts.

[0014] Exemplarily, the zinc salt is selected from zinc sulfate, zinc chloride, or zinc acetate.

[0015] Exemplarily, the copper salt is selected from copper sulfate, copper chloride, or copper acetate.

[0016] In any of the above technical solutions, the diluted oil emulsion contains 20-40 wt% of oil agent, 1-2 wt% of antistatic agent, 2-3 wt% of emulsifier, 1-3 wt% of water-soluble metal salt, and the balance is water.

[0017] Exemplarily, the emulsifier is selected from one or more of nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and hydrogenated castor oil polyoxyethylene ether.

[0018] Exemplarily, the oil agent is selected from one or more of mineral oil, synthetic ester, and silicone oil.

[0019] Exemplarily, the antistatic agent is selected from one or more of cationic quaternary ammonium salt, fatty alcohol polyoxyethylene ether phosphate ester, alkyl sulfonate, and alkylphenol polyoxyethylene ether sulfate salt.

[0020] In the oiling process, zinc salt or copper salt is introduced, and metal ions are loaded onto the fiber surface through the diluted oil emulsion. Under the high-temperature drawing effect in the drawing process, the metal ions diffuse into the amorphous region of the fiber and form stable coordination complexes with the -NH2 groups in the amino-modified polypropylene. This process can enhance the intermolecular force between the molecular chains in the amorphous region of the fiber, increase the glass transition temperature (Tg), thereby inhibiting the wear caused by chain segment slippage during the friction process of the fiber, and improving the abrasion resistance of the polypropylene fiber.

[0021] In any of the above technical solutions, a pre-network is carried out between the oiling and the drawing, and the pre-network air pressure is 0.03-0.05 MPa.

[0022] After the oil agent is coated and before the drawing, a pre-network step (air pressure 0.03-0.05 MPa) is added. The diluted oil emulsion is uniformly coated on the surface of the monofilament by the disturbance of low-pressure air flow, avoiding local aggregation or insufficient penetration of the oil agent. The low air pressure design ensures that the fiber is only slightly disturbed and does not form periodic nodes in the traditional network process, thus maintaining the mechanical uniformity of the fiber. The uniformly distributed oil agent layer can accelerate the directional migration of metal ions during high-temperature drawing, making it more efficient to coordinate with amino groups. At the same time, the lubricating effect of the oil agent reduces the friction coefficient between the fiber and the guide roller during the drawing process, reduces the generation of surface hairiness, and further synergistically improves the abrasion resistance.

[0023] In any of the above technical solutions, the drawing includes a first-stage drawing and a second-stage drawing. The temperature of the first-stage drawing is 60-80 °C, the temperature of the second-stage drawing is 100-120 °C, and the total drawing ratio is 3-4.

[0024] In the second aspect, the present application provides a method for preparing a dyeable and wear-resistant polypropylene fiber. According to the raw material ratio of any of the above polypropylene fibers, the raw materials are blended and melted to obtain a melt, and the melt is made into fibers through spinning, cooling, oiling, drawing, crimping, and heat setting.

[0025] In any of the above technical solutions, the spinning box body is at 245 - 265°C, the ring blowing wind speed is 0.6 - 0.8 m / min, the wind temperature is 20 - 25°C, and the spinning speed is 800 - 1000 m / min.

[0026] In any of the above technical solutions, the heat setting temperature is 120 - 130°C.

[0027] In summary, the present application has the following beneficial effects:

[0028] Through the molecular design of amino - modified polypropylene, the strengthening of metal ion coordination, and the optimization of the pre - network process, the present application realizes the coordinated improvement of the dyeability and wear resistance of polypropylene fibers. The introduction of amino groups endows the fibers with an efficient dyeing site function, and the dye uptake rate is significantly higher than that of traditional polypropylene fibers. Moreover, the high compatibility with the polypropylene matrix ensures the breaking strength of the fibers. The high - temperature penetration and non - crystalline region coordination of metal ions increase the glass transition temperature, effectively improving the wear resistance. At the same time, the low - pressure pre - network process optimizes the oil agent distribution and coordination efficiency, further reducing frictional damage. This solution realizes the simultaneous improvement of the dyeing performance and wear resistance while retaining the light - weight and water - repellent characteristics of polypropylene fibers. Specific Embodiments

[0029] Preparation Examples

[0030] Preparation Example 1, amino - modified polypropylene, is prepared according to the following steps:

[0031] Mix 1 kg of maleic anhydride - grafted polypropylene (grafting rate 1.5%, OREVAC® 18729) with 0.1 kg of polyethyleneimine (molecular weight 1800, Bo'ao Tuoda), and put it into a co - rotating twin - screw extruder (length - diameter ratio 40:1). Set the temperature zones of the extruder: zone 1 at 180°C, zone 2 at 190°C, zone 3 at 200°C, zone 4 at 200°C, zone 5 at 200°C, and the die head at 200°C. The screw speed is 200 rpm, the melting and mixing time is 8 min, and then extrusion granulation is carried out to obtain amino - modified polypropylene.

[0032] Preparation Example 2, amino - modified polypropylene, is prepared according to the following steps:

[0033] Mix 1 kg of maleic anhydride - grafted polypropylene (grafting rate 2.0%, Coace®PP - g - MAH B1) with 0.13 kg of polyethyleneimine (molecular weight 800, Macklin), and put it into a co - rotating twin - screw extruder. Set the temperature zones of the extruder: zone 1 at 190°C, zone 2 at 200°C, zone 3 at 210°C, zone 4 at 210°C, zone 5 at 210°C, and the die head at 210°C. The screw speed is 220 rpm, the melting and mixing time is 5 min, and then extrusion granulation is carried out to obtain amino - modified polypropylene.

[0034] Preparation Example 3, amino - modified polypropylene, is prepared according to the following steps:

[0035] 1kg of maleic anhydride grafted polypropylene (grafting rate 1.0%, BONDYRAM®PP-g-MAH 1010) was mixed with 0.08kg of polyethyleneimine (molecular weight 2000, Biotuoda) and put into a co-rotating twin-screw extruder. The extruder temperature zones were set as follows: zone 1 185℃, zone 2 195℃, zone 3 205℃, zone 4 205℃, zone 5 205℃, and die head 205℃. The screw speed was 200rpm, the melt mixing time was 10min, and the amino-modified polypropylene was obtained by extrusion granulation.

[0036] Preparation Example 4, amino-modified polypropylene, is different from Preparation Example 1 in that the molecular weight of polyethyleneimine is 2500 (McLean).

[0037] Preparation Example 5, amino-modified polypropylene, is different from Preparation Example 1 in that the molecular weight of polyethyleneimine is 600 (McLean).

[0038] Preparation Example 6, amino-modified polypropylene, is different from Preparation Example 1 in that polyethyleneimine (molecular weight 1800, Bio-Total) is replaced by an equal amount of triethylenetetramine.

[0039] Preparation Example 7, amino-modified polypropylene, is different from Preparation Example 1 in that polyethyleneimine (molecular weight 1800, Biotoda) is replaced by an equal amount of tetraethylenepentamine.

[0040] Example

[0041] Example 1, an easy-to-dye and wear-resistant polypropylene fiber is prepared according to the following steps:

[0042] 10kg of polypropylene (Sico PP S2040) and 1.5kg of amino-modified polypropylene obtained in Preparation Example 1 were added to a twin-screw extruder, mixed at 220°C, extruded and water-cooled, and cut into composite slices using a granulator. The obtained composite slices were placed in a vacuum dryer at 95°C for 10 hours, transported to a melt spinning machine to melt, and the melt was ejected from the spinning spinneret at a spinning temperature of 260°C to obtain a monofilament. The monofilament was then cooled in a ring wind at a wind temperature of 21±1°C and a wind speed of 0.8m / min, and a diluent oil emulsion was supplied to the monofilament with an oil nozzle for bundling. The monofilament had an oil content of 0.7% after oiling, and the oiling temperature was 50°C. The bundled tow entered the pre-network device, and the pre-network air pressure was 0.04MPa. After leaving the pre-network device, the tow is drawn by the godet roller and enters the first and second drawing stages in sequence. The first drawing temperature is 72°C, the drawing multiple is 1.6, and the second drawing temperature is 110°C, the drawing multiple is 2. After drawing, the tow passes through the godet roller and enters the winder for winding. Finally, it is heat-set at 122-126°C for 10 minutes to obtain an easy-to-dye and wear-resistant polypropylene fiber with a fineness of 1.2dtex.

[0043] The diluted oil emulsion contains 35 wt % of silicone oil (Dow Corning DC-200), 1.5 wt % of antistatic agent (cationic quaternary ammonium salt, Akzo Nobel Armostat 600), 2.5 wt % of emulsifier (nonylphenol polyoxyethylene ether NP-10), 2.0 wt % of zinc sulfate, and 59 wt % of water.

[0044] Example 2, an easy-to-dye and wear-resistant polypropylene fiber is prepared according to the following steps:

[0045] 10kg of polypropylene (Sico PP S2040) and 1.0kg of amino-modified polypropylene obtained in Preparation Example 2 were added to a twin-screw extruder, mixed at 230°C, extruded and water-cooled, and cut into composite slices using a granulator. The obtained composite slices were placed in a vacuum dryer at 90°C for 10 hours, transported to a melt spinning machine to melt, and the melt was ejected from the spinning spinneret at a spinning temperature of 265°C to obtain a monofilament. The monofilament was then cooled in a ring wind at a wind temperature of 24±1°C and a wind speed of 0.6m / min, and a diluent oil emulsion was supplied to the monofilament with an oil nozzle for bundling. The monofilament had an oil content of 0.6% after oiling, and the oiling temperature was 50°C. The bundled tow entered the pre-network device, and the pre-network air pressure was 0.03MPa. After leaving the pre-network device, the tow is drawn by the godet roller and enters the first and second drawing stages in sequence. The first drawing temperature is 80°C, the drawing multiple is 1.5, and the second drawing temperature is 120°C, the drawing multiple is 2. After drawing, the tow passes through the godet roller and enters the winder for winding. Finally, it is heat-set at 122-126°C for 10 minutes to obtain an easy-to-dye and wear-resistant polypropylene fiber with a fineness of 1.2dtex.

[0046] The above-mentioned diluent oil emulsion contains 35wt% of synthetic ester, 1.0wt% of antistatic agent (fatty alcohol polyoxyethylene ether phosphate, BASF Lutensit A-EP), 3.0wt% of emulsifier (hydrogenated castor oil polyoxyethylene ether EL-40), 3.0wt% of copper sulfate, and 68wt% of water.

[0047] Example 3, an easy-to-dye and wear-resistant polypropylene fiber is prepared according to the following steps:

[0048] 10kg of polypropylene (Sico PP S2040) and 2.0kg of amino-modified polypropylene obtained in Preparation Example 3 were added to a twin-screw extruder, mixed at 220°C, extruded and water-cooled, and cut into composite slices using a granulator. The obtained composite slices were placed in a vacuum dryer at 95°C for 12 hours, transported to a melt spinning machine to melt, and the melt was ejected from the spinning spinneret at a spinning temperature of 245°C to obtain a monofilament. The monofilament was then cooled in a ring wind at a wind temperature of 21±1°C and a wind speed of 0.5m / min, and a diluent oil emulsion was supplied to the monofilament with an oil nozzle for bundling. The monofilament had an oil content of 0.8% after oiling, and the oiling temperature was 50°C. The bundled tow entered the pre-network device, and the pre-network air pressure was 0.05MPa. After leaving the pre-network device, the tow is drawn by the godet roller and enters the first and second drawing stages in sequence. The first drawing temperature is 60°C, the drawing multiple is 2, and the second drawing temperature is 100°C, the drawing multiple is 2. After drawing, the tow passes through the godet roller and enters the winder for winding. Finally, it is heat-set at 120-124°C for 13 minutes to obtain a 1.2dtex easy-to-dye and wear-resistant polypropylene fiber.

[0049] The diluted oil emulsion contains 40 wt % of mineral oil, 2.0 wt % of antistatic agent (sodium alkyl sulfonate, Dow Triton X-100), 2.5 wt % of emulsifier (fatty alcohol polyoxyethylene ether AEO-9), 1.0 wt % of zinc chloride and 55 wt % of water.

[0050] Example 4, an easy-to-dye and wear-resistant polypropylene fiber, is different from Example 1 in that it is directly stretched without pre-networking after oiling.

[0051] Example 5, an easy-to-dye and wear-resistant polypropylene fiber, is different from Example 1 in that the amino-modified polypropylene obtained in Preparation Example 1 is replaced by an equal amount of the amino-modified polypropylene obtained in Preparation Example 4.

[0052] Example 6, an easy-to-dye and wear-resistant polypropylene fiber, differs from Example 1 in that the amino-modified polypropylene obtained in Preparation Example 1 is replaced by an equal amount of the amino-modified polypropylene obtained in Preparation Example 5.

[0053] Comparative Example

[0054] Comparative Example 1, an easy-to-dye and wear-resistant polypropylene fiber, is different from Example 1 in that an equal amount of maleic anhydride grafted polypropylene (grafting rate 1.5%, OREVAC® 18729) is used to replace the amino-modified polypropylene obtained in Preparation Example 1.

[0055] Comparative Example 2, an easy-to-dye and wear-resistant polypropylene fiber, is different from Example 4 in that the amino-modified polypropylene obtained in Preparation Example 1 is replaced by an equal amount of maleic anhydride-grafted polypropylene (grafting rate 1.5%, OREVAC® 18729).

[0056] Comparative Example 3: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 4 in that an equal amount of polypropylene (Sekisui PPS2040) is used to replace the amino-modified polypropylene obtained in Preparation Example 1.

[0057] Comparative Example 4: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 6 in that the raw materials of the polypropylene fiber are 10 kg of polypropylene (Sekisui PP S2040) and 1.5 kg of polyethylene terephthalate (intrinsic viscosity 0.4 dL / g, melting point 220 - 230 °C).

[0058] Comparative Example 5: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 1 in that the amino-modified polypropylene obtained in Preparation Example 6 is used to replace the amino-modified polypropylene obtained in Preparation Example 1 in an equal amount.

[0059] Comparative Example 6: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 1 in that the amino-modified polypropylene obtained in Preparation Example 7 is used to replace the amino-modified polypropylene obtained in Preparation Example 1 in an equal amount.

[0060] Comparative Example 7: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 1 in that zinc sulfate is not added to the dilution oil emulsion, and an equal amount of water is used to replace zinc sulfate.

[0061] Comparative Example 8: An easily dyeable and wear-resistant polypropylene fiber, which is different from Example 1 in that zinc sulfate is not added to the dilution oil emulsion, and an equal amount of water is used to replace zinc sulfate; and after oiling, pre-networking is not carried out, and drawing is directly carried out.

[0062] Performance Detection Test

[0063] 1. Dye Uptake Test

[0064] Specimen Preparation: The fibers of the examples and comparative examples are made into yarns (yarn count 40 Ne, twist 650 twists / m) through a ring spinning machine, woven with a plain weave, the fabric density is 120 warp ends / 10 cm and 80 weft ends / 10 cm, and the gram weight is 150 g / m 2 . The fabric is subjected to 3 standard washes according to GB / T8629-2017 "Textiles - Home Laundering and Drying Procedures for Testing", to remove surface sizing agents and impurities.

[0065] Testing method: Refer to GB / T 23976.1-2009 "Textiles - Tests for colour fastness - Part 1: Colour fastness to washing", and conduct the test in combination with the acid dyeing process. Specifically, immerse the fiber sample (1.0 g) into the dye bath containing 2% (o.w.f) acid dye (C.1.Acid Red57), with a bath ratio of 1:50 and pH = 4.5 (adjusted with acetic acid). Heat the bath to 95 °C at a rate of 2 °C / min, keep it at this temperature for 60 min, then take out the fiber after cooling to room temperature and wash it with cold water. Use a UV-visible spectrophotometer (UV-2600, Shimadzu) to measure the absorbance of the dyebath residue at λ = 520 nm, and calculate the dye uptake rate as follows:

[0066] Dye uptake rate (%) = (1 - A1 / A0) × 100%

[0067] Where A0 is the absorbance of the blank dyebath, and A1 is the absorbance of the dyebath residue after dyeing.

[0068] 2. Abrasion resistance test

[0069] Refer to GB / T 21196.3-2007 "Textiles - Determination of fabric abrasion resistance using the Martindale method" to test the polypropylene fiber. Fix the fiber monofilament on a reciprocating friction testing machine (YG401E), apply a loading pressure of 0.5 cN / dtex, use a 400-mesh sandpaper as the friction head, and the friction frequency is 60 times / min. Record the number of friction times when obvious fuzzing or breakage appears on the fiber surface, and take the average value of 10 tests for each group.

[0070] 3. Tensile strength test

[0071] Conduct the test according to GB / T 14344-2008 "Test method for tensile properties of chemical fiber filaments". Use a universal material testing machine (Instron 3365), with a clamping distance of 20 mm and a tensile speed of 20 mm / min, to test the single-filament breaking strength. Take the average value of 30 tests for each group of samples, and calculate the tensile strength (cN / dtex) in combination with the fineness.

[0072] Table 1. Performance test results

[0073]

[0074] Analysis of test results:

[0075] (1) The dye uptake rates of Examples 1 - 3 are all higher than 80%, indicating that amino-modified polypropylene significantly improves the dye uptake rate. In Comparative Examples 1 - 3, no amino modification was carried out, and the dye uptake rates all decreased significantly, verifying the key role of amino groups as "dyeing sites".

[0076] (2) The wear resistance times of Examples 1 to 3 were significantly higher than those of the comparative examples, which was attributed to the coordination of metal ions with amino groups enhancing the intermolecular forces between the molecular chains in the amorphous region. Moreover, compared with polar polymers such as polyester, amino-modified polypropylene had good compatibility with the polypropylene matrix, which was beneficial to ensuring the strength and wear resistance of polypropylene fibers. The wear resistance of Comparative Example 7 (without metal salt in the finishing agent) decreased by about 28%, that of Comparative Example 1 (not amino-modified but with metal ions in the finishing agent) decreased by about 30%, and that of Comparative Example 2 (not amino-modified and without metal ions in the finishing agent) decreased by about 30.5%, which proved the contribution of the coordination of metal ions with amino groups to wear resistance. The wear resistance of Example 5 (without pre-network) decreased by about 13%, and that of Comparative Example 8 (without metal salt and without pre-network) decreased by about 37%, which proved the contribution of the pre-network process to wear resistance.

[0077] (3) The breaking strength of Example 1 was higher than 3.8 cN / dtex, which was significantly better than that of Comparative Example 4 (2.3 cN / dtex), proving that amino-modified polypropylene had good compatibility with the matrix compared with polyester, avoiding mechanical deterioration caused by phase separation. The strengths of Comparative Example 7 (without metal salt), Comparative Example 1 (not amino-modified but with metal ions in the finishing agent), Comparative Example 2 (not amino-modified and without metal ions in the finishing agent), Example 5 (without pre-network) and Comparative Example 8 (without pre-network and without metal salt) decreased, indicating that the coordination of metal salts in the finishing agent with amino groups in the fiber and the pre-network process could reduce fiber damage during the drawing process by evenly distributing the finishing agent.

[0078] (4) The dyeing performance of Example 1 (83.2%) was slightly higher than those of Examples 5 to 6 (79.7%, 80.6%), proving that using polyethyleneimine with a molecular weight Mn of 800 to 2000 was helpful to improve the dyeing rate of polypropylene fibers. The reason might be that the reaction efficiency of polyethyleneimine in this molecular weight range with maleic anhydride-grafted polypropylene was relatively high, which was helpful to increase the amino density in the fiber and the content of dyeing sites.

[0079] (5) The dye uptake rate of Example 1 (83.2%) was significantly higher than those of Comparative Examples 5 to 6 (60.7%, 64.3%), indicating that using polyethyleneimine as the amino grafting compound could produce polypropylene with a higher amino grafting rate compared with small molecule polyalkylene polyamine, thereby obtaining polypropylene fibers with a high dye uptake rate.

[0080] This specific embodiment is only an interpretation of the present application, and it is not a limitation of the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An easy-to-dye and wear-resistant polypropylene fiber, characterized in that: The invention comprises polypropylene and amino-modified polypropylene in a mass ratio of 100:10-20, wherein the amino-modified polypropylene is obtained by reacting maleic anhydride grafted polypropylene as a precursor with polyethyleneimine, the mass ratio of maleic anhydride grafted polypropylene to polyethyleneimine is 10:0.8-1.3, and the molecular weight of the polyethyleneimine is 800-2000; the polypropylene fiber is obtained by melt spinning, cooling, oiling, drawing, curling, and heat setting, wherein the oiling adopts a diluent oil emulsion, and the diluent oil emulsion contains 1-3wt% of a water-soluble metal salt; the water-soluble metal salt is selected from zinc salt or copper salt.

2. The polypropylene fiber according to claim 1, characterized in that The grafting rate of the maleic anhydride grafted polypropylene is 1-2%.

3. The polypropylene fiber according to claim 1, characterized in that The reaction temperature is 180-210°C.

4. The polypropylene fiber according to claim 1, characterized in that The diluent oil emulsion comprises 20-40 wt% of oil agent, 1-2 wt% of antistatic agent, 2-3 wt% of emulsifier, 1-3 wt% of water-soluble metal salt, and the balance is water.

5. The polypropylene fiber according to claim 1, characterized in that Pre-networking is performed between the oiling and the drawing, and the pre-networking air pressure is 0.03-0.05 MPa.

6. The polypropylene fiber according to claim 1, characterized in that The stretching process includes one stretching process and two stretching processes, the temperature of the first stretching process is 60-80° C., the temperature of the second stretching process is 100-120° C., and the total stretching multiple is 3-4.

7. A method for preparing easy-to-dye and wear-resistant polypropylene fiber, characterized in that: According to the raw material ratio of the polypropylene fiber according to any one of claims 1 to 6, the raw materials are blended and melted to obtain a melt, and the melt is produced by spinning, cooling, oiling, drawing, curling and heat setting.

Images