Polypropylene fiber as well as preparation method and application thereof

Abstract

The invention relates to the field of chemical fibers, and discloses a polypropylene fiber and a preparation method and application thereof. The preparation method of the polypropylene fiber comprises the following steps: (1) melting water-soluble polyester and polypropylene to obtain an intermediate I; the intrinsic viscosity of the water-soluble polyester is 0.5-0.8 dL / g, and the dosage weight ratio of the water-soluble polyester to the polypropylene is 1: (1-9); (2) carrying out spinning treatment on the intermediate I to obtain an intermediate II; and (3) dissolving the intermediate II to obtain the polypropylene fiber. The polypropylene fiber prepared by the method provided by the invention has the advantages of high water absorption, good heat preservation and light weight, and can be widely applied to sports wear materials, heat preservation filling materials and the like.

Description

Technical Field

[0001] This invention relates to the field of chemical fibers, specifically to a polypropylene fiber, its preparation method, and its applications. Background Technology

[0002] When the human body engages in strenuous exercise, a large amount of sweat is produced on the skin surface. If the sweat remains on the skin surface for a long time, the body will experience strong discomfort. Therefore, sportswear fabrics need to be made of absorbent and sweat-wicking chemical fibers so that the sweat can be quickly absorbed from the skin surface.

[0003] In addition, sportswear should be water-repellent, allowing absorbed sweat to quickly evaporate into the air for rapid drying and improved comfort. Furthermore, to prevent hypothermia after exercise, sportswear should also have good thermal insulation properties. Finally, sportswear should be lightweight to make exercise easier and more comfortable.

[0004] Currently, the fabrics used in moisture-wicking sportswear are microporous polyester fibers, which have a microporous structure on their surface. In contrast, polypropylene, which is highly absorbent, heat-insulating, and lightweight, not only has micron and submicron microporous structures on its surface but also micron hollow structures. Furthermore, polypropylene has a lower density and better water repellency than polyester fibers. Therefore, polypropylene has advantages in terms of moisture absorption and quick-drying properties, heat insulation, and lightweight design.

[0005] CN102453967A discloses a method for preparing hollow polyester fibers with controllable hollowness. This method uses two screw extruders to feed a core-sheath spinneret assembly. The sheath layer is composed of polyester and water-soluble polyester, and the core layer is water-soluble polyester. These are melt-spun together in a specific ratio, followed by post-processing to obtain polyester staple fibers. Fabrics made from these fibers are treated with an alkaline solution to remove the water-soluble polyester components from the core and sheath layers, thus forming a hollow structure with numerous micropores, grooves, and through-holes on both the inner and outer surfaces. The fiber has a core-sheath structure, with the sheath composed of polyester and water-soluble polyester, and the core layer composed of water-soluble polyester. The weight ratio of polyester to water-soluble polyester in the sheath layer is (75–95):(5–25), and the weight ratio of the sheath layer to the core layer is (35–95):(5–65). The hollowness of the hollow fibers obtained by controlling the raw material ratio is 5–75%. However, the lightweight and heat insulation properties of this polyester fiber still need to be improved. Summary of the Invention

[0006] The purpose of this invention is to provide a polypropylene fiber that combines water absorption and quick-drying properties with heat retention and lightweight properties.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for preparing polypropylene fibers, the method comprising the following steps:

[0008] (1) Water-soluble polyester and polypropylene are melt-treated to obtain intermediate I;

[0009] The intrinsic viscosity of the water-soluble polyester is 0.5-0.8 dL / g, and the weight ratio of the water-soluble polyester to the polypropylene is 1:1-9.

[0010] (2) Spinning intermediate I to obtain intermediate II;

[0011] (3) Dissolve the intermediate II to obtain the polypropylene fiber;

[0012] The temperature of the spinning treatment is greater than or equal to the temperature of the melting treatment, and the difference between the temperature of the spinning treatment and the temperature of the melting treatment is 0-20℃.

[0013] The second aspect of the present invention provides polypropylene fibers prepared by the method described in the first aspect above.

[0014] A third aspect of the present invention provides the application of the polypropylene fiber described in the second aspect above in sportswear fabrics.

[0015] The polypropylene fiber prepared by the method provided in this invention contains a sheath and a core; the sheath contains grooves and / or microporous structures, and the core has a hollow structure.

[0016] The polypropylene fiber prepared by the method provided by this invention has the advantages of high water absorption, good heat retention and lightweight, and can be widely used in sportswear materials, heat insulation filling materials and other fields. Attached Figure Description

[0017] Figure 1 This is a microstructure diagram of the polypropylene fiber prepared in Example 1 of the present invention. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] As previously described, a first aspect of the present invention provides a method for preparing polypropylene fibers, the method comprising the following steps:

[0020] (1) Water-soluble polyester and polypropylene are melt-treated to obtain intermediate I;

[0021] The intrinsic viscosity of the water-soluble polyester is 0.5-0.8 dL / g, and the weight ratio of the water-soluble polyester to the polypropylene is 1:1-9.

[0022] (2) Spinning intermediate I to obtain intermediate II;

[0023] (3) Dissolve the intermediate II to obtain the polypropylene fiber;

[0024] The temperature of the spinning treatment is greater than or equal to the temperature of the melting treatment, and the difference between the temperature of the spinning treatment and the temperature of the melting treatment is 0-20℃.

[0025] Preferably, in step (1), the polypropylene is fiber-grade polypropylene, and its melt index is 10-60 g / 10 min under test conditions of 190°C and 2.16 kg. The inventors of this invention have found that, under this preferred condition, the resulting polypropylene fiber has better mechanical properties, and its breaking strength can reach 3 cN / dtex.

[0026] Preferably, the weight ratio of the water-soluble polyester to the polypropylene is 1:1-6. The inventors of this invention have found that, under this preferred condition, the resulting polypropylene fiber has a higher water absorption rate and a lower density.

[0027] In a preferred embodiment, in step (1), the conditions for the melting process include: a temperature of 230-260°C and a rotation speed of 200-600 rpm.

[0028] Preferably, the melt treatment is performed by screw heating melt extrusion.

[0029] Preferably, in step (2), the conditions for the spinning process include: a temperature of 250-280℃ and a speed of 2000-3500m / min.

[0030] In a preferred embodiment, the conditions for the dissolution treatment in step (3) include: a temperature of 80-100°C and a time of 3-8 min.

[0031] In this invention, there are no special requirements for the solvent used in the dissolution process; those skilled in the art can choose according to their needs. For example, deionized water is used as the solvent in the dissolution process.

[0032] As previously stated, the second aspect of the present invention provides polypropylene fibers prepared by the method described in the first aspect.

[0033] Preferably, the polypropylene fiber comprises a sheath and a core; the sheath comprises grooves and / or microporous structures, and the core is a hollow structure; the volume ratio of the sheath to the core is 1:1.5-9.

[0034] Preferably, the diameter of the trench and the average pore diameter of the micropores in the microporous structure are each independently 0.2-3 μm.

[0035] It should be noted that, in this invention, the diameter of the groove is 0.5-2 μm.

[0036] In a preferred embodiment, the cross-section of the hollow structure is circular and the diameter of the circle is 2-10 μm.

[0037] Preferably, the polypropylene fiber has a single filament fineness of 0.5-10 dtex.

[0038] More preferably, the polypropylene fiber has a single filament fineness of 2-5 dtex.

[0039] This invention does not particularly limit the type of polypropylene fiber, which can be POY fiber, FDY fiber, DTY fiber, or short fiber. Specifically, POY fiber is obtained by high-speed spinning; FDY fiber is obtained by low-speed spinning followed by solid stretching; DTY fiber is obtained by texturing POY fiber; and short fiber is obtained by crimping and cutting FDY fiber. Those skilled in the art can adjust the spinning process as needed.

[0040] The present invention does not impose any special requirements on the solid stretching and the texturing treatment; any person with expertise in the art can choose according to their needs.

[0041] Compared with ordinary polypropylene, the polypropylene fiber provided by this invention has a wicking effect on water due to its micron and submicron hollow structure and surface microporous structure, which can absorb water more quickly; secondly, because the hollow structure and surface microporous structure are filled with air, the overall thermal conductivity is low, which makes the polypropylene fiber have better heat preservation performance; at the same time, the polypropylene fiber has less mass under the same packing volume, with a weight reduction rate of more than 20%.

[0042] As previously stated, a third aspect of the present invention provides the application of the polypropylene fiber described in the second aspect in sportswear fabrics.

[0043] The present invention will be described in detail below through examples. Unless otherwise specified, the instruments, reagents, and materials involved in the following examples are all conventional instruments, reagents, and materials, which can be obtained through legitimate commercial channels. Unless otherwise stated, all reagents used are commercially available analytical grade products.

[0044] Water-soluble polyester: purchased from Anhui Wanwei Group Co., Ltd.

[0045] In the following examples of the present invention, different raw material formulations are used. Unless otherwise specified, the amount of raw materials used is in parts by weight, and each part by weight represents 100g.

[0046] Example 1

[0047] The method for preparing the polypropylene fiber (DTY fiber) includes the following steps:

[0048] (1) 30 parts by weight of water-soluble polyester (intrinsic viscosity of 0.5 dL / g) and 70 parts by weight of polypropylene (melt index of 60 g / 10 min, fiber grade) were melt-extruded by screw heating (260°C) to obtain intermediate I;

[0049] (2) Spinning intermediate I (260°C, spinning speed 3000m / min) to obtain intermediate II (fiber specification 75dtex / 36F);

[0050] (3) The intermediate II is dissolved in deionized water (dissolved at 95°C for 4 min), and then texturing is performed to obtain the polypropylene fiber (DTY fiber).

[0051] Example 2

[0052] The method for preparing the polypropylene fiber (FDY fiber) includes the following steps:

[0053] (1) 40 parts by weight of water-soluble polyester (intrinsic viscosity of 0.6 dL / g) and 60 parts by weight of polypropylene (melt index of 40 g / 10 min, fiber grade) were melt-extruded by screw heating (270°C) to obtain intermediate I;

[0054] (2) The intermediate I is spun (270°C) and then stretched in a solid state (stretching ratio of 3.6 times, stretching temperature of 50°C, setting temperature of 110°C, winding speed of 3200m / min) to obtain intermediate II (fiber specification of 144dtex / 96F).

[0055] (3) The intermediate II was dissolved in deionized water (dissolved at 95°C for 5 min) to obtain the polypropylene fiber (FDY fiber).

[0056] Test case

[0057] The microstructure of the polypropylene fibers obtained in Example 1 was tested using scanning electron microscopy, such as... Figure 1 As shown, through Figure 1 It can be seen that the surface of the polypropylene fiber obtained by the method of the present invention has a microporous structure.

[0058] The polypropylene fiber prepared by the method provided by this invention has the advantages of high water absorption, good heat retention and lightweight, and can be widely used in sportswear materials, heat insulation filling materials and other fields.

[0059] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A process for the preparation of polypropylene fibres, characterised in that, The method comprises the following steps: (1) melt treating water-soluble polyester and polypropylene to obtain intermediate I; The intrinsic viscosity of the water-soluble polyester is 0.5-0.8 dL / g, and the weight ratio of the water-soluble polyester to the polypropylene is 1:1-9; (2) spinning treating the intermediate I to obtain intermediate II; (3) dissolving treating the intermediate II to obtain the polypropylene fiber; The temperature of the spinning treating is higher than the temperature of the melt treating, and the difference between the temperature of the spinning treating and the temperature of the melt treating is 0-20℃.

2. The method of claim 1, wherein, In step (1), the melt index of the polypropylene under the test condition of 190℃ and 2.16 kg is 10-60 g / 10 min; And / or the weight ratio of the water-soluble polyester to the polypropylene is 1:1-6.

3. The method of claim 1 or 2, wherein, In step (1), the melt treating condition comprises: the temperature is 230-260℃, and the rotating speed is 200-600 rpm.

4. The method of any of claims 1-3, wherein, In step (2), the spinning treating condition comprises: the temperature is 250-280℃, and the speed is 2000-3500 m / min.

5. The method of any of claims 1-4, wherein, In step (3), the dissolving treating condition comprises: the temperature is 80-100℃, and the time is 3-8 min.

6. The polypropylene fiber prepared by the method of any one of claims 1-5.

7. The polypropylene fiber according to claim 6, wherein, The polypropylene fiber comprises a skin layer and a core; the skin layer comprises a groove and / or a microporous structure, and the core is a hollow structure; the volume ratio of the skin layer to the core is 1:1.5-9.

8. The polypropylene fiber according to claim 6 or 7, wherein The diameter of the groove and the average pore diameter of the micropores in the microporous structure are each independently 0.2-3 μm; and / or The cross section of the hollow structure is circular, and the diameter of the circular shape is 2-10 μm.

9. The polypropylene fiber according to any one of claims 6 to 8, wherein, The single-fiber fineness of the polypropylene fiber is 0.5-10 dtex, preferably 2-5 dtex.

10. The use of the polypropylene fiber of any one of claims 6-9 in sports wear fabric.

Images