Double-layer-structure high-strength composite fiber and preparation method thereof

Abstract

The invention relates to the technical field of fibers, and discloses a high-strength composite fiber with a double-layer structure and a preparation method thereof.The composite fiber comprises a composite polyester fiber and an antibacterial modified layer wrapping the composite polyester fiber, and the composite polyester fiber is prepared from PET slices serving as main raw materials, modified diamond and the like serving as auxiliary materials, the modified diamond is prepared by carrying out in-situ polymerization on macromolecular substances on the surface of the diamond, the macromolecular substances can generate strong interaction force with PET molecular chains to form an interlaced net structure, the effect of the diamond can be efficiently exerted, the mechanical strength of fibers can be enhanced, and meanwhile, the mechanical strength of the fibers can be improved. By means of the unique multi-layer structural design, the chitosan layer wraps the composite polyester fiber, and the spectrum antibacterial effect of chitosan is utilized, so that the prepared composite fiber can show good antibacterial performance.

Description

Technical Field

[0001] The present invention relates to the field of fiber technology, and in particular to a double-layer high-strength composite fiber and a preparation method thereof. Background Art

[0002] Polyester (polyester fiber) is the world's most produced synthetic fiber, ranking first in total chemical fiber production. Polyester fiber is manufactured using melt spinning technology, whereby spun fibers are formed through melt extrusion, followed by stretching and heat setting to obtain the final product. Its molecular chain is composed of alternating rigid benzene rings and flexible aliphatic hydrocarbon chains. This structure imparts high crystallinity and orientation to the fiber, resulting in excellent overall performance.

[0003] However, with the rapid development of materials technology, in response to the requirements of various industries, the improvement of the multifunctionality of polyester fibers has become a trend. Since polyester fibers themselves do not have antibacterial properties, there are application defects in fields such as close-fitting clothing fabrics that require antibacterial properties. In addition, although polyester fibers themselves have certain strength performance, they are gradually unable to meet the needs in actual applications.

[0004] At present, the functional modification of polyester fibers is generally carried out by using functional additives and compounding them with polyester chips to form composite fibers. However, there are interface problems between the additives and the polyester chips themselves. The incompatibility effect between them will greatly reduce the modification effect of the additives. The addition of a large amount of inorganic additives will even have a negative impact on the comprehensive performance of the fiber. Based on this, the present invention designs the structure and formula of the fiber to prepare a composite fiber with good comprehensive performance, which can solve the problems existing in the prior art. Summary of the Invention

[0005] In order to solve the problems mentioned in the background technology, the purpose of the present invention is to provide a double-layer structure high-strength composite fiber and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A double-layer high-strength composite fiber, comprising a composite polyester fiber and an antibacterial modified layer coated on the outside of the composite polyester fiber;

[0008] The composite polyester fiber is made of the following raw materials measured in parts by weight:

[0009] 45-65 parts of PET chips, 1-3.5 parts of modified diamond, 1-3 parts of lubricant, and 0.5-1 part of antioxidant.

[0010] As a further embodiment of the present invention, the method for preparing the composite polyester fiber comprises the following steps:

[0011] Step A: Weigh each component according to weight to complete the material preparation;

[0012] Step B: adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder for melt extrusion granulation, and then transferring the masterbatch to a melt spinning machine for melt spinning to form nascent fibers;

[0013] Step C, stretching the spun fiber 3-5 times in warm water at 40-50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0014] As a further embodiment of the present invention, the method for preparing the modified diamond comprises the following steps:

[0015] Step S1, adding diamond to concentrated nitric acid for acidification to obtain acid-modified diamond;

[0016] Step S2: In an N,N-dimethylformamide medium, firstly use a diazine derivative as a linker to further modify the acid-modified diamond under the action of a catalyst, then add a chain extender and perform in-situ polymerization with the diazine derivative to obtain a modified diamond.

[0017] As a further solution of the present invention, in step S1, the temperature during the acidification treatment is 90-100° C. and the time is 2-4 hours.

[0018] As a further embodiment of the present invention, in step S2, the catalyst is p-toluenesulfonic acid or aminosulfonic acid.

[0019] As a further embodiment of the present invention, in step S2, the chain extender is 1,2,3,4-cyclopentanetetracarboxylic dianhydride.

[0020] As a further embodiment of the present invention, in step S2, the mass ratio of the naphthyridine derivative, the acid-modified diamond and the chain extender is 1.8-2.6:1:1.2-1.8.

[0021] As a further embodiment of the present invention, in step S2, the naphthyridine derivative is prepared by reacting 6-bromo-2,3-naphthyridine and diethanolamine as raw materials in the presence of a promoter.

[0022] As a further embodiment of the present invention, in step S2, the accelerator is triethylamine.

[0023] In the above technical solution, the diamond is first acidified with concentrated nitric acid to carry active carboxyl substituents on its surface, thereby producing acid-modified diamond. Next, 1,4-dihydroxy-2,3-naphthyridine is used as a linker to undergo esterification condensation with the carboxyl substituents of the acid-modified diamond under the action of a catalyst. A chain extender is then added to undergo continuous esterification reactions with the 1,4-dihydroxy-2,3-naphthyridine in the system, and in situ polymerization is performed on the diamond surface, forming a macromolecular substance on the diamond surface that is connected by ester bonds and has a block cyclopentane-naphthyridine alternating connection structure, namely, modified diamond.

[0024] A method for preparing a double-layer high-strength composite fiber comprises the following steps:

[0025] The first step is to dissolve chitosan in an acetic acid solution with a mass fraction of 1-2% to prepare a chitosan solution with a mass fraction of 5-15%;

[0026] The second step is to immerse the composite polyester fiber in the chitosan solution and disperse it evenly by ultrasonication. Then, calcium chloride is added to the formed dispersion. After the addition is completed, the temperature is raised to 50-60°C and the stirring is continued for 4-8 hours to form a chitosan antibacterial modified layer on the surface of the composite polyester fiber. The material is cooled and discharged, and dried.

[0027] In the above technical solution, a chitosan solution is first prepared, and then the composite polyester fiber is immersed in the chitosan solution so that the chitosan macromolecules are wrapped around the outside of the composite polyester fiber. Then, calcium chloride is used as a cross-linking agent to achieve cross-linking of the chitosan, thereby wrapping a dense cross-linked chitosan antibacterial modified layer around the outside of the composite polyester fiber.

[0028] Beneficial effects of the present invention:

[0029] The present invention prepares modified diamond by in-situ polymerizing a macromolecular substance on the surface of diamond. In the subsequent melt extrusion process, the diazine ring can produce a conjugated effect with the benzene ring structure in the PET molecular chain, thereby generating a strong interaction force between the macromolecular substance and the PET molecular chain, forming an interwoven network structure. The diamond plays a core role in the network structure, which not only can produce good interface performance between the diamond and the PET substrate, avoiding the problem of negative impact on the material due to interface problems, but also can utilize the network core of the diamond and the reinforcing effect of the diamond itself as an inorganic reinforcing agent to achieve efficient absorption, dispersion and transfer of external stress, thereby effectively enhancing the mechanical strength of the fiber. At the same time, the rigid ring in the macromolecular substance structure can improve the stability and strength of the PET molecular chain, so that the prepared composite polyester fiber exhibits high strength characteristics.

[0030] The present invention adopts a unique multi-layer structure design, wraps a chitosan layer on the outside of the composite polyester fiber, and utilizes the spectral antibacterial effect of chitosan to enable the prepared composite fiber to exhibit good antibacterial performance.

[0031] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Preparation Example

[0034] Preparation method of modified diamond:

[0035] Step S1, adding 3.6 g of diamond to 100 mL of concentrated nitric acid, stirring and mixing until uniform, then heating, and acidifying at 90° C. for 3 h to obtain acid-modified diamond;

[0036] Step S2, adding 0.3 g of 6-bromo-2,3-diazinone and 0.14 g of diethanolamine to toluene, stirring to form a mixed solution, then adding 0.05 g of triethylamine to the mixed solution, passing nitrogen protection, then heating to 75° C., keeping the temperature and stirring for 6 hours, evaporating the solvent, cooling and discharging the material to obtain a diazinone derivative;

[0037] Step S3: Add 1.2 g of acid-modified diamond to an N,N-dimethylformamide medium and disperse it evenly by ultrasonication. Then, add 3 g of a naphthyridine derivative and 0.1 g of p-toluenesulfonic acid to the formed dispersion. After the addition is completed, raise the temperature to 100° C. and keep it warm for 3 hours. Then, add 1.8 g of 1,2,3,4-cyclopentanetetracarboxylic dianhydride, further raise the temperature to 120° C., and continue stirring for 16 hours to obtain modified diamond.

[0038] The ester group content of the modified diamond was titrated using the soap back titration method. 0.3 g of modified diamond was taken as the test sample. The test results showed that the ester group content of the test sample was 8.159 mmol / g. It can be inferred that the ester group was formed by ring-opening esterification polymerization of a diazine derivative and 1,2,3,4-cyclopentanetetracarboxylic dianhydride.

[0039] Example 1

[0040] Preparation of composite polyester fiber:

[0041] Step A: Weigh 45 parts of PET chips, 1 part of modified diamond, 1 part of lubricant polyethylene wax, and 0.5 part of antioxidant 1010 to complete the material preparation;

[0042] Step B, adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder, controlling the temperature of each zone to: 240°C in zone 1, 250°C in zone 2, 260°C in zone 3, 270°C in zone 4, and 260°C in zone 5, for melt extrusion, and then transferring the obtained masterbatch to a melt spinning machine for melt spinning to form spun fibers;

[0043] Step C: stretching the spun fiber 3 times in warm water at 50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0044] The specific preparation method of the modified diamond is shown in the preparation example, and the same applies to the following.

[0045] Example 2

[0046] Preparation of composite polyester fiber:

[0047] Step A: Weigh 50 parts of PET chips, 3 parts of modified diamond, 2 parts of lubricant polyethylene wax, and 0.6 parts of antioxidant 1010 to complete the material preparation;

[0048] Step B, adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder, controlling the temperature of each zone to: 240°C in zone 1, 250°C in zone 2, 260°C in zone 3, 270°C in zone 4, and 260°C in zone 5, for melt extrusion, and then transferring the masterbatch to a melt spinning machine for melt spinning to form spun fibers;

[0049] Step C: stretching the spun fiber 3 times in warm water at 50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0050] Example 3

[0051] Preparation of composite polyester fiber:

[0052] Step A: Weigh 65 parts of PET chips, 3.5 parts of modified diamond, 3 parts of lubricant polyethylene wax, and 1 part of antioxidant 1010 to complete the material preparation;

[0053] Step B, adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder, controlling the temperature of each zone to: 240°C in zone 1, 250°C in zone 2, 260°C in zone 3, 270°C in zone 4, and 260°C in zone 5, for melt extrusion, and then transferring the masterbatch to a melt spinning machine for melt spinning to form spun fibers;

[0054] Step C: stretching the spun fiber 3 times in warm water at 50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0055] Comparative Example 1

[0056] Preparation of composite polyester fiber:

[0057] Step A: Weigh 50 parts of PET chips, 3 parts of diamond, 2 parts of lubricant polyethylene wax, and 0.6 parts of antioxidant 1010 to complete the material preparation;

[0058] Step B, adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder, controlling the temperature of each zone to: 240°C in zone 1, 250°C in zone 2, 260°C in zone 3, 270°C in zone 4, and 260°C in zone 5, for melt extrusion, and then transferring the masterbatch to a melt spinning machine for melt spinning to form spun fibers;

[0059] Step C: stretching the spun fiber 3 times in warm water at 50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0060] Comparative Example 2

[0061] Preparation of composite polyester fiber:

[0062] Step A: Weigh 50 parts of PET chips, 2 parts of lubricant polyethylene wax, and 0.6 parts of antioxidant 1010 to complete the material preparation;

[0063] Step B, adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder, controlling the temperature of each zone to: 240°C in zone 1, 250°C in zone 2, 260°C in zone 3, 270°C in zone 4, and 260°C in zone 5, for melt extrusion, and then transferring the masterbatch to a melt spinning machine for melt spinning to form spun fibers;

[0064] Step C: stretching the spun fiber 3 times in warm water at 50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

[0065] Performance testing

[0066] According to the standard GB / T 14344-2008, the mechanical properties of the composite polyester fibers in the examples and comparative examples were tested. The results are shown in Table 1:

[0067] Table 1

[0068]

[0069]

[0070] According to the test results, the composite polyester fiber prepared in the embodiment of the present invention has significantly higher mechanical strength and high-strength characteristics. After the modified diamond is replaced with diamond that has not been surface-modified, on the one hand, the poor interface problem causes the diamond to be unable to fully exert its effectiveness, and the reinforcement modification effect is poor. On the other hand, the rigidity and stability brought by the macromolecular substance are lost, which will also cause the strength of the polyester composite fiber to decrease.

[0071] A double-layer high-strength composite fiber was prepared using the composite polyester fibers in the examples and comparative examples. The specific preparation method includes the following steps:

[0072] The first step is to dissolve chitosan in an acetic acid solution with a mass fraction of 2% to prepare a chitosan solution with a mass fraction of 15%;

[0073] The second step is to immerse 10g of composite polyester fiber in 120mL of chitosan solution and disperse it evenly by ultrasonication. Then, 1.5g of calcium chloride is added to the formed dispersion. After the addition is completed, the temperature is raised to 60°C and stirred for 6 hours to form a chitosan antibacterial modification layer on the surface of the composite polyester fiber. The material is cooled and discharged, and dried.

[0074] The composite fiber was woven into fabrics with a warp density of 30 yarns / cm and a weft density of 25 yarns / cm. The antibacterial rate test was conducted according to the standard GB / T 20944.3-2008. Staphylococcus aureus was selected as the test bacteria. The test results are shown in Table 2:

[0075] Table 2

[0076] Antibacterial rate (%) Example 1 95.8 Example 2 95.8 Example 3 95.7 Comparative Example 1 95.5 Comparative Example 2 95.7

[0077] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A double-layer high-strength composite fiber, characterized in that: The invention comprises a composite polyester fiber and an antibacterial modified layer coated on the outside of the composite polyester fiber; The composite polyester fiber is made of the following raw materials measured in parts by weight: 45-65 parts of PET chips, 1-3.5 parts of modified diamond, 1-3 parts of lubricant, and 0.5-1 part of antioxidant.

2. The double-layer high-strength composite fiber according to claim 1, characterized in that: The preparation method of the composite polyester fiber comprises the following steps: Step A: Weigh each component according to weight to complete the material preparation; Step B: adding each component to a high-speed mixer, mechanically stirring and mixing until uniform, then feeding into a twin-screw extruder for melt extrusion granulation, and then transferring the masterbatch to a melt spinning machine for melt spinning to form nascent fibers; Step C, stretching the spun fiber 3-5 times in warm water at 40-50° C., taking it out, and performing a shaping treatment to obtain a composite polyester fiber.

3. The double-layer high-strength composite fiber according to claim 1, characterized in that: The preparation method of the modified diamond comprises the following steps: Step S1, adding diamond to concentrated nitric acid for acidification to obtain acid-modified diamond; Step S2: In an N,N-dimethylformamide medium, firstly use a diazine derivative as a linker to further modify the acid-modified diamond under the action of a catalyst, then add a chain extender and perform in-situ polymerization with the diazine derivative to obtain a modified diamond.

4. The double-layer high-strength composite fiber according to claim 3, characterized in that: In step S1, the temperature during the acidification treatment is 90-100° C. and the time is 2-4 hours.

5. The double-layer high-strength composite fiber according to claim 3, characterized in that: In step S2, the catalyst is p-toluenesulfonic acid or aminosulfonic acid.

6. The double-layer high-strength composite fiber according to claim 3, characterized in that: In step S2, the chain extender is 1,2,3,4-cyclopentanetetracarboxylic dianhydride.

7. The double-layer high-strength composite fiber according to claim 3, characterized in that: In step S2, the mass ratio of the naphthyridine derivative, the acid-modified diamond and the chain extender is 1.8-2.6:1:1.2-1.

8.

8. The double-layer high-strength composite fiber according to claim 3, characterized in that: In step S2, the naphthyridine derivative is prepared by reacting 6-bromo-2,3-naphthyridine and diethanolamine as raw materials in the presence of a promoter.

9. The double-layer high-strength composite fiber according to claim 8, characterized in that: In step S2, the accelerator is triethylamine.

10. A method for preparing a double-layer high-strength composite fiber according to claim 1, characterized in that: The following steps are involved: The first step is to dissolve chitosan in an acetic acid solution with a mass fraction of 1-2% to prepare a chitosan solution with a mass fraction of 5-15%; The second step is to immerse the composite polyester fiber in the chitosan solution and disperse it evenly by ultrasonication. Then, calcium chloride is added to the formed dispersion. After the addition is completed, the temperature is raised to 50-60°C and the stirring is continued for 4-8 hours to form a chitosan antibacterial modified layer on the surface of the composite polyester fiber. The material is cooled and discharged, and dried.

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