Cutting-resistant ultra-high molecular weight polyethylene fiber with reduced exfoliation, and manufacturing method and application of cutting-resistant ultra-high molecular weight polyethylene fiber

Abstract

The invention relates to a cut-resistant ultra-high molecular weight polyethylene fiber with reduced exfoliation, and a manufacturing method and application thereof. The ultra-high molecular weight polyethylene fiber of the present invention has a core and a skin covering at least a portion of the surface of the core, in which the core comprises hard fibers and optionally hard particles dispersed in the core polyethylene, and the skin comprises a reduced content of the hard fibers compared to the core. According to the invention, the additive in the fiber can be effectively prevented from falling off, so that the product achieves a better anti-cutting effect.

Description

Technical Field

[0001] The present invention relates to the field of high-performance fibers, and in particular to a cut-resistant ultra-high molecular weight polyethylene fiber with reduced shedding, a manufacturing method thereof and applications thereof. Background Art

[0002] Ultra-high molecular weight polyethylene fiber is the preferred fiber in the field of cut-resistant gloves due to its high strength and cut-resistant properties. In order to pursue the best balance between performance and comfort, various forms of hard component additives are currently added to the fiber to keep the fiber soft and comfortable while improving cut resistance. However, in actual applications, we found that due to the smooth surface and dense structure of ultra-high molecular weight polyethylene fiber, this additive is difficult to combine with the fiber and is easily detached during the spinning and stretching process. In the process of weaving gloves, it falls off in large quantities at the friction parts, affecting the cut-resistant effect and causing environmental pollution. Especially when the additive is a needle-shaped component such as glass fiber or mineral fiber, the products dropped during the production process will cause harm to the human body (same as the harm of asbestos). Summary of the invention

[0003] The purpose of the present invention is to manufacture a cut-resistant ultra-high molecular weight polyethylene fiber that can effectively prevent the internal additive from falling off in view of the deficiencies of the prior art. In the fiber spinning process of the present invention, because decalin is a good solvent for ultra-high molecular weight polyethylene, polyethylene is dissolved at high temperature to form a spinning solution. The viscosity of the solution formed by polyethylene with different molecular weights and decalin is different. The smaller the molecular weight, the smaller the viscosity and the better the fluidity. In the process of forming the fiber from the spinning solution, the decalin is quickly moved to the surface for flash evaporation through rapid high-multiple drafting. At this time, the solution formed by low molecular weight polyethylene has low viscosity and fast forward movement, and first migrates to the surface. In the link of quickly removing the solvent, about 97% of the decalin will be removed, and the low molecular weight polyethylene used in the present invention also has a molecular weight of hundreds of thousands to millions, so it also has a certain fiber-forming property, and a microfiber shell structure will be formed on the surface. This microfiber shell plays a fixing role on the additive, thereby achieving the purpose of preventing it from falling off.

[0004] Specifically, the present invention relates to the following aspects.

[0005] 1. An ultra-high molecular weight polyethylene fiber having a core and a sheath covering at least a portion (preferably substantially all) of the surface of the core, wherein the core comprises hard fibers and optional hard particles dispersed in the core polyethylene, and the sheath comprises a reduced content of the hard fibers compared to the core.

[0006] 2. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the viscosity-average molecular weight of the sheath polyethylene is 300,000-1.5 million (preferably 400,000-800,000), and the viscosity-average molecular weight of the core polyethylene is 2-20 times (preferably 3-10 times) the viscosity-average molecular weight of the core polyethylene.

[0007] 3. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the content of the hard fiber is at most 50 parts by weight (preferably 3-10 parts by weight) relative to 100 parts by weight of the core polyethylene, and the content of the hard particles is 0-20 parts by weight (preferably 0.5-5 parts by weight).

[0008] 4. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the content of the hard fiber is 0-30 parts by weight (preferably 0-3 parts by weight, more preferably substantially 0) relative to 100 parts by weight of the sheath polyethylene.

[0009] 5. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the Mohs hardness of the hard fiber is greater than the Mohs hardness of the ultra-high molecular weight polyethylene, and the Mohs hardness of the hard particles is greater than the Mohs hardness of the ultra-high molecular weight polyethylene.

[0010] 6. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the hard fiber is a one-dimensional linear structure with a diameter of up to 20 μm (preferably 3-10 μm), an aspect ratio of 3-1000 (preferably 5-50), and a length of 10-2000 μm (preferably 30-300 μm).

[0011] 7. The ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, wherein the hard fiber is selected from at least one of inorganic hard fibers and organic hard fibers, preferably selected from at least one of inorganic hard fibers.

[0012] 8. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the inorganic hard fiber is selected from at least one of metal fiber, glass fiber, ceramic fiber, mineral fiber, and basalt fiber, or the organic hard fiber is selected from at least one of carbon fiber, aramid fiber, aromatic polyamide copolymer fiber, heterocyclic polyamide fiber, graphite fiber, silicon carbide fiber, wood fiber, bamboo fiber, sisal fiber, and yew fiber.

[0013] 9. The ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, wherein the average diameter of the hard particles is not greater than 20 μm (preferably 0.5-2 μm).

[0014] 10. The ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, wherein the hard particles are selected from at least one of inorganic hard particles and organic hard particles, preferably at least one of inorganic hard particles.

[0015] 11. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the inorganic hard particles are selected from at least one of metal particles, glass particles, ceramic particles, mineral particles, vitrified microspheres, and fly ash, or the organic hard particles are selected from at least one of silicone micropowder, amino micropowder, polyacrylate micropowder, polylactic acid micropowder, and polytetrafluoroethylene micropowder.

[0016] 12. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the hard fiber and / or the hard particle has been subjected to surface chemical modification, such as surface chemical modification with a silane coupling agent.

[0017] 13. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the silane coupling agent is selected from at least one of aminopropyltriethoxysilane, γ-(glycidyloxy)propyltrimethoxysilane, and γ-(methacryloyloxy)propyltrimethoxysilane.

[0018] 14. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the hard fiber and / or the hard particle has undergone surface physical modification, such as surface roughening treatment and / or surface polymer coating treatment.

[0019] 15. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the polymer is selected from at least one of thermoplastic polymers, thermosetting polymers and rubbers, and preferably selected from at least one of cellulose esters, olefin polymers (polyvinyl acetate, polyvinyl alcohol, perchlorethylene, polyisobutylene, etc.), polyesters, polyethers, polyamides, polyacrylates, a-cyanoacrylates, polyvinyl acetals, ethylene-vinyl acetate copolymers and isocyanates.

[0020] 16. The ultra-high molecular weight polyethylene fiber of any preceding or following aspect, wherein the intrinsic viscosity of the core polyethylene is 2-20 times (preferably 3-10 times) the intrinsic viscosity of the sheath polyethylene.

[0021] 17. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the intrinsic viscosity of the sheath polyethylene is not greater than 15 g / dl (preferably 4-10 g / dl), and the intrinsic viscosity of the core polyethylene is at least 10 g / dl (preferably 15-25 g / dl).

[0022] 18. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the viscosity average molecular weight of the sheath polyethylene is 300,000-1.5 million (preferably 400,000-800,000).

[0023] 19. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the average diameter is at most 50 μm (preferably 10-30 μm), and the average diameter of the core is at most 40 μm (preferably 10-25 μm).

[0024] 20. The ultra-high molecular weight polyethylene fiber of any preceding or following aspect, wherein the average diameter of the core is 70% to less than 100% (preferably 80% to less than 100%) of the average diameter of the ultra-high molecular weight polyethylene fiber.

[0025] 21. The ultra-high molecular weight polyethylene fiber of any preceding or following aspect, wherein the sheath covers at least a portion of the surface of the core with a predetermined thickness, and the predetermined thickness has a non-uniformity exceeding 10% (e.g. exceeding 50%).

[0026] 22. The ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, wherein the sheath is generated in situ by a spinning method, or the sheath has no bonding interface with the core.

[0027] 23. The ultra-high molecular weight polyethylene fiber described in any of the preceding or following aspects, wherein the single fiber fineness is 0.7-5 dtex (preferably 1.7-2.7 dtex).

[0028] 24. The ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, wherein the bending rigidity of the single fiber is 0.05×10 -5 -3×10 -5 cN / dtex (preferably 0.1×10 -5 -2×10 -5 cN / dtex), and the breaking strength is 10-45 cN / dtex (preferably 20-40 cN / dtex).

[0029] 25. A method for producing ultra-high molecular weight polyethylene fiber, comprising the following steps:

[0030] 1) mixing ultra-high molecular weight polyethylene, low molecular weight polyethylene, hard fibers, solvent and optional hard particles to prepare a spinning solution,

[0031] 2) extruding the spinning solution through a spinneret to form a spinning fine stream,

[0032] 3) while stretching the spinning stream, removing at least a portion (e.g., at least 50 wt%, preferably at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% or at least 97 wt%) of the solvent from the spinning stream to obtain the ultra-high molecular weight polyethylene fiber (referred to as spun fiber),

[0033] The ratio of the drawing speed to the extrusion speed of the spinning fine stream is 1-20 (preferably 2-10).

[0034] 26. The manufacturing method described in any of the preceding or subsequent aspects, wherein relative to 100 parts by weight of the ultra-high molecular weight polyethylene, the amount of the low molecular weight polyethylene is at most 50 parts by weight (preferably 5-20 parts by weight), the amount of the hard fiber is at most 50 parts by weight (preferably 3-10 parts by weight), the amount of the hard particles is 0-20 parts by weight (preferably 0.5-5 parts by weight), and the amount of the solvent is at least 500 parts by weight (preferably 1000-2000 parts by weight).

[0035] 27. The manufacturing method described in any of the preceding or following aspects, wherein in step 1), the hard fiber and the ultra-high molecular weight polyethylene are first dry-mixed, and then the obtained mixture is mixed with other components.

[0036] 28. The manufacturing method described in any of the above or the following aspects, wherein before performing step 2), it also includes a step of combing and orienting the spinning solution.

[0037] 29. The production method described in any of the preceding or following aspects, wherein in step 1), the solvent is selected from at least one of naphthalene and its hydrogenated derivatives, decahydronaphthalene, tetrahydronaphthalene, kerosene, xylene, toluene, petroleum fractions, halogenated hydrocarbons, cycloalkanes, and cycloalkenes, preferably decahydronaphthalene.

[0038] 30. The manufacturing method described in any of the above or below aspects, wherein in step 1), the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 9 million (preferably 3 million to 5 million), and the viscosity-average molecular weight of the low molecular weight polyethylene is 100,000 to 2.8 million (preferably 400,000 to 1.5 million).

[0039] 31. The manufacturing method described in any of the above or below aspects, wherein the viscosity average molecular weight of the low molecular weight polyethylene is 0.2-0.8 times (preferably 0.3-0.5 times) the viscosity average molecular weight of the ultra-high molecular weight polyethylene.

[0040] 32. The production method described in any of the preceding or following aspects, wherein the intrinsic viscosity of the low molecular weight polyethylene is 0.2-0.8 times (preferably 0.3-0.5 times) the intrinsic viscosity of the ultra-high molecular weight polyethylene.

[0041] 33. The manufacturing method described in any of the above or below aspects, wherein the intrinsic viscosity of the low molecular weight polyethylene is not more than 18 g / dl (preferably 5-10 g / dl), and the intrinsic viscosity of the ultra-high molecular weight polyethylene is 10-45 g / dl (preferably 15-35 g / dl).

[0042] 34. The manufacturing method described in any of the preceding or following aspects, wherein in step 2), the extrusion temperature is 150-220°C (preferably 160-200°C), and the extrusion speed is 2-20m / min (3-10m / min).

[0043] 35. The manufacturing method described in any of the preceding or following aspects, wherein the spinning stream is immediately subjected to step 3) after leaving the spinneret.

[0044] 36. The manufacturing method described in any of the preceding or following aspects, wherein in step 3), the operating conditions include: temperature of 70-180°C (preferably 140-160°C), blowing height of not less than 0.2m (preferably 5-15m), and air volume of 50-180m3 / h (preferably 90-150m3 / h).

[0045] 37. The manufacturing method described in any of the above or the following aspects, wherein in step 3), the stretching speed is not less than 2 m / min (preferably 5-20 m / min), and the stretching ratio is not less than 2 (preferably 3-10).

[0046] 38. The manufacturing method described in any of the preceding or following aspects, wherein in step 3), the stretching and the solvent removal are carried out simultaneously, and the duration is not less than 2 minutes (preferably 3-10 minutes).

[0047] 39. The manufacturing method described in any of the preceding or following aspects, wherein after step 3), the spun fiber is stretched in one or more stages (such as 1-8 or 2-5 stages) (referred to as post-stretching).

[0048] 40. The manufacturing method described in any of the above or below aspects, wherein the operating conditions of the post-stretching include: the stretching temperature is 90-160°C (preferably 130-150°C), and the (overall) stretching ratio is 2-30 (preferably 5-15).

[0049] 41. A fabric comprising the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, or made of the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects, or made of the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects and other fibers.

[0050] 42. The fabric described in any of the preceding or following aspects further comprises at least one other fiber selected from natural plant fibers, natural animal fibers, artificial regenerated fibers, synthetic fibers and inorganic fibers.

[0051] Technical Effects

[0052] Add low molecular weight polyethylene (molecular weight less than 1 million), and by controlling the solvent diffusion and volatilization rate ratio, make the low molecular weight polyethylene diffuse to the fiber surface with the solvent to form a microfiber shell structure. This microfiber shell structure can effectively prevent the additive inside the fiber from falling off, so that the product can achieve better anti-cutting effect. The breaking strength of the fiber obtained by the present invention is 15-40cN / dtex. The prepared fiber is woven into a standard glove, and the EN-388 mechanical injury protective gloves are tested for cut resistance. The cut resistance index is greater than 20, that is, it reaches cut resistance level 5. The cut-resistant fiber involved in the present invention is not only suitable for cut-resistant gloves, but also can be used in various fields with cut resistance requirements, such as protective clothing in meat processing, metal processing, mechanical assembly, wood processing, sports fields, etc., to prevent people from being cut, and can be made into gloves, aprons, sleeves, cuffs, pants, tops, etc. Because the fiber does not reduce the comfort while ensuring the cut resistance, it can not only be used for various types of cut-resistant gloves and outerwear, but also for underwear. In addition, it can also be used for various types of cut-resistant fabrics, including packaging fabrics, luggage, commercial decoration, transportation industry, fire hose protective covers, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the bending stiffness of a single wire. DETAILED DESCRIPTION

[0054] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0055] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definitions in this specification shall prevail.

[0056] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0057] In the context of the present invention, all numerical values ​​for parameters (eg amounts or conditions) are to be understood as being modified in all instances by the term "about", regardless of whether "about" actually appears before the numerical value.

[0058] In the context of the present invention, the average diameter is measured by microscopic measurement, and the average value is taken from 5 measurements of the maximum diameter.

[0059] In the context of the present invention, the thickness unevenness rate is measured by scanning and measuring using a Keyence VR6000 3D profile measuring instrument, the number of measurements is 10 times, and the unevenness rate calculation formula is:

[0060] In the context of the present invention, the method for measuring the monofilament fineness is GB / T 14343.

[0061] In the context of the present invention, the method for measuring the bending stiffness of a single fiber is to take a fiber sample of 50 mm to 70 mm, place the fiber vertically, and clamp the upper and lower ends by the upper and lower clamps respectively. Before the lower clamp is closed, the fixed weight tension clamp ensures that the fiber is in a straight but not stretched state. The upper clamp in the device is fixed and connected to a force sensor, so that the axial stress magnitude and the bending force of the fiber can be obtained in real time. The lower clamp is connected to the transmission mechanism and can move at a constant speed in the vertical direction under the drive of a stepper motor. In the single fiber bending test, the lower clamp first rises at a constant speed at a set speed, and the fiber is subjected to an axial bending force. As the displacement of the lower clamp gradually increases, the fiber is compressed in the axial direction until it bends, and the bending deformation gradually increases.

[0062] In the context of the present invention, the measuring method of breaking strength is GB / T 19975.

[0063] In the context of this specification, the shedding of hard fibers from ultra-high molecular weight polyethylene fibers is characterized by the severity of material shedding during the manufacturing process of the ultra-high molecular weight polyethylene fibers.

[0064] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0065] In the context of the present invention, any two or more embodiments or aspects of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0066] According to one embodiment of the present invention, it is related to an ultra-high molecular weight polyethylene fiber, comprising a core and a sheath covering at least a portion (preferably substantially all) of the surface of the core. According to the present invention, the sheath is generated in situ by a spinning method, and is not additionally coated on the core by a coating method or the like. To this end, according to the present invention, the sheath has no bonding interface with the core, and the two constitute a whole.

[0067] According to one embodiment of the present invention, the core comprises hard fibers and optional hard particles dispersed in the core polyethylene, and the sheath comprises the hard fibers in a reduced content compared to the core. In other words, the content of hard fibers (and hard particles, if any) in the sheath is lower than that in the core, thereby achieving a shedding (mainly hard fiber shedding) inhibition effect. According to the present invention, substantially no hard fibers or hard particles are found in the sheath, thereby the ultra-high molecular weight polyethylene fiber of the present invention can exhibit an excellent shedding inhibition effect compared to the prior art.

[0068] According to one embodiment of the present invention, the content of the hard fiber is at most 50 parts by weight (preferably 3-10 parts by weight) relative to 100 parts by weight of the core polyethylene, and the content of the hard particles is 0-20 parts by weight (preferably 0.5-5 parts by weight). In contrast, the content of the hard fiber is 0-30 parts by weight (preferably 0-3 parts by weight, more preferably substantially 0) relative to 100 parts by weight of the skin polyethylene.

[0069] According to one embodiment of the present invention, the viscosity average molecular weight of the skin polyethylene is 300,000-1.5 million (preferably 400,000-800,000), and the viscosity average molecular weight of the core polyethylene is 2-20 times (preferably 3-10 times) the viscosity average molecular weight of the skin polyethylene. If the viscosity average molecular weight is too low, there is no fiber-forming property or the strength after fiber-forming is very low, and there is no practical value; if the viscosity average molecular weight is too high, the difficulty of spinning increases, the skin layer migration is not obvious, and an obvious skin-core structure cannot be formed.

[0070] According to one embodiment of the present invention, the intrinsic viscosity of the core polyethylene is 2-20 times (preferably 3-10 times) the intrinsic viscosity of the sheath polyethylene.

[0071] According to one embodiment of the present invention, the Mohs hardness of the hard fiber is greater than the Mohs hardness of the ultra-high molecular weight polyethylene, and the Mohs hardness of the hard particles is greater than the Mohs hardness of the ultra-high molecular weight polyethylene.

[0072] According to one embodiment of the present invention, the hard fiber is a one-dimensional linear structure with a diameter of at most 20 μm (preferably 3-10 μm), an aspect ratio of 3-1000 (preferably 5-50), and a length of 10-2000 μm (preferably 30-300 μm).

[0073] According to one embodiment of the present invention, the hard fiber is selected from at least one of inorganic hard fibers and organic hard fibers, preferably selected from at least one of inorganic hard fibers.

[0074] According to one embodiment of the present invention, the inorganic hard fiber is selected from at least one of metal fiber, glass fiber, ceramic fiber, mineral fiber, and basalt fiber, or the organic hard fiber is selected from at least one of carbon fiber, aramid fiber, aromatic polyamide copolymer fiber, heterocyclic polyamide fiber, graphite fiber, silicon carbide fiber, wood fiber, bamboo fiber, sisal fiber, and yew fiber.

[0075] According to one embodiment of the present invention, the average diameter of the hard particles is no greater than 20 μm (preferably 0.5-2 μm).

[0076] According to one embodiment of the present invention, the hard particles are selected from at least one of inorganic hard particles and organic hard particles, preferably at least one of inorganic hard particles.

[0077] According to one embodiment of the present invention, the inorganic hard particles are selected from at least one of metal particles, glass particles, ceramic particles, mineral particles, vitrified microspheres, and fly ash, or the organic hard particles are selected from at least one of silicone micropowder, amino micropowder, polyacrylate micropowder, polylactic acid micropowder, and polytetrafluoroethylene micropowder.

[0078] According to one embodiment of the present invention, the hard fibers and / or the hard particles are / is subjected to surface chemical modification treatment, such as surface chemical modification treatment with a silane coupling agent.

[0079] According to one embodiment of the present invention, the silane coupling agent is selected from at least one of aminopropyltriethoxysilane, γ-(glycidyloxy)propyltrimethoxysilane and γ-(methacryloyloxy)propyltrimethoxysilane.

[0080] According to one embodiment of the present invention, the hard fibers and / or the hard particles are subjected to surface physical modification treatment, such as surface roughening treatment and / or surface polymer coating treatment.

[0081] According to one embodiment of the present invention, the polymer is selected from at least one of thermoplastic polymers, thermosetting polymers and rubbers, preferably selected from at least one of cellulose esters, olefin polymers (polyvinyl acetate, polyvinyl alcohol, perchlorethylene, polyisobutylene, etc.), polyesters, polyethers, polyamides, polyacrylates, a-cyanoacrylates, polyvinyl acetals, ethylene-vinyl acetate copolymers and isocyanates.

[0082] According to one embodiment of the present invention, the intrinsic viscosity of the sheath polyethylene is not more than 15 g / dl (preferably 4-10 g / dl), and the intrinsic viscosity of the core polyethylene is at least 10 g / dl (preferably 15-25 g / dl).

[0083] According to one embodiment of the present invention, the viscosity average molecular weight of the skin polyethylene is 300,000-1.5 million (preferably 400,000-800,000).

[0084] According to one embodiment of the present invention, the average diameter of the ultra-high molecular weight polyethylene fiber is at most 50 μm (preferably 10-30 μm).

[0085] According to one embodiment of the present invention, the average diameter of the core is at most 40 μm (preferably 10-25 μm).

[0086] According to one embodiment of the present invention, the average diameter of the core is 70% to less than 100% (preferably 80% to less than 100%) of the average diameter of the ultra-high molecular weight polyethylene fiber. The thickness of the cortex needs to be within a reasonable range. If the cortex is too thick, it is easy to break and peel off from the core layer under the action of high-multiple stretching during the post-drawing process. If the cortex is too thin, it cannot play the role of fixing the additive and the anti-shedding effect is poor.

[0087] According to one embodiment of the present invention, the skin covers at least a portion of the surface of the core with a predetermined thickness, and the unevenness of the predetermined thickness exceeds 10% (for example, exceeds 50%). The skin layer of the present invention is actually formed during the spinning process due to the surface migration and solidification of low molecular weight components. Different from the post-coating effect, the in-situ generation is greatly affected by the wind field, the rate of solvent removal, the process conditions, and the environmental conditions, and has a certain degree of randomness. Therefore, the thickness unevenness is much higher than the post-coating process.

[0088] According to one embodiment of the present invention, the single filament fineness of the ultra-high molecular weight polyethylene fiber is 0.7-5 dtex (preferably 1.7-2.7 dtex).

[0089] According to one embodiment of the present invention, the flexural rigidity of the single fiber of the ultra-high molecular weight polyethylene fiber is 0.05×10 -5 -3×10 -5 cN / dtex (preferably 0.1×10 -5 -2×10 -5 cN / dtex), and the breaking strength is 10-45 cN / dtex (preferably 20-40 cN / dtex).

[0090] According to one embodiment of the present invention, a method for producing ultra-high molecular weight polyethylene fiber is also provided, comprising the following steps:

[0091] 1) mixing ultra-high molecular weight polyethylene, low molecular weight polyethylene, hard fibers, solvent and optional hard particles to prepare a spinning solution,

[0092] 2) extruding the spinning solution through a spinneret to form a spinning fine stream,

[0093] 3) while stretching the spinning stream, removing at least a portion (e.g., at least 50 wt%, preferably at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% or at least 97 wt%) of the solvent from the spinning stream to obtain the ultra-high molecular weight polyethylene fiber (referred to as spun fiber).

[0094] According to one embodiment of the present invention, the ratio of the stretching speed to the extrusion speed of the spinning stream is 1-20 (preferably 2-10). If it is too small, the diffusion is insufficient and an effective shell cannot be formed. If it is too large, the drafting difficulty increases, the fiber strength decreases, or the filaments break and fail to form.

[0095] According to one embodiment of the present invention, the amount of the low molecular weight polyethylene is at most 50 parts by weight (preferably 5-20 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0096] According to one embodiment of the present invention, the amount of the hard fiber is at most 50 parts by weight (preferably 3-10 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0097] According to one embodiment of the present invention, the amount of the hard particles is 0-20 parts by weight (preferably 0.5-5 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0098] According to one embodiment of the present invention, the amount of the solvent is at least 500 parts by weight (preferably 1000-2000 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0099] According to one embodiment of the present invention, in step 1), the hard fiber and the ultra-high molecular weight polyethylene are first dry-mixed, and then the obtained mixture is mixed with other components.

[0100] According to one embodiment of the present invention, before performing step 2), a step of combing and orienting the spinning solution is also included.

[0101] According to one embodiment of the present invention, in step 1), the solvent is selected from at least one of naphthalene and its hydrogenated derivatives decalin, tetralin, kerosene, xylene, toluene, petroleum fractions, halogenated hydrocarbons, cycloalkanes, and cycloolefins, preferably decalin.

[0102] According to one embodiment of the present invention, in step 1), the viscosity average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 9 million (preferably 3 million to 5 million), and the viscosity average molecular weight of the low molecular weight polyethylene is 100,000 to 2.8 million (preferably 400,000 to 1.5 million).

[0103] According to one embodiment of the present invention, the viscosity average molecular weight of the low molecular weight polyethylene is 0.2-0.8 times (preferably 0.3-0.5 times) the viscosity average molecular weight of the ultra-high molecular weight polyethylene.

[0104] According to one embodiment of the present invention, the intrinsic viscosity of the low molecular weight polyethylene is 0.2-0.8 times (preferably 0.3-0.5 times) the intrinsic viscosity of the ultra-high molecular weight polyethylene.

[0105] According to one embodiment of the present invention, the intrinsic viscosity of the low molecular weight polyethylene is not more than 18 g / dl (preferably 5-10 g / dl), and the intrinsic viscosity of the ultra-high molecular weight polyethylene is 10-45 g / dl (preferably 15-35 g / dl).

[0106] According to one embodiment of the present invention, in step 2), the extrusion temperature is 150-220° C. (preferably 160-200° C.), and the extrusion speed is 2-20 m / min (3-10 m / min).

[0107] According to one embodiment of the present invention, the spinning stream is immediately subjected to step 3) after leaving the spinneret.

[0108] According to one embodiment of the present invention, in step 3), the operating conditions include: temperature of 70-180°C (preferably 140-160°C), blowing height of not less than 0.2m (preferably 5-15m), air volume of 50-180m3 / h (preferably 90-150m3 / h).

[0109] According to one embodiment of the present invention, in step 3), the stretching speed is not less than 2 m / min (preferably 5-20 m / min), and the stretching ratio is not less than 2 (preferably 3-10).

[0110] According to one embodiment of the present invention, in step 3), the stretching and the solvent removal are carried out simultaneously, and the duration is not less than 2 minutes (preferably 3-10 minutes).

[0111] According to one embodiment of the present invention, after step 3), the spun fiber is stretched in one or more stages (such as 1-8 or 2-5 stages) (referred to as post-stretching).

[0112] According to one embodiment of the present invention, the post-stretching operation conditions include: a stretching temperature of 90-160° C. (preferably 130-150° C.), and an (overall) stretching ratio of 2-30 (preferably 5-15).

[0113] According to one embodiment of the present invention, a fabric is also provided, comprising the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects of this specification, or made of the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects of this specification, or made of the ultra-high molecular weight polyethylene fiber described in any one of the preceding or following aspects of this specification and other fibers. According to the present invention, the fabric may include, for example, gloves, labor protection products, protective clothing, backpacks, military cut-resistant fabrics or civilian cut-resistant fabrics.

[0114] According to one embodiment of the present invention, the fabric further comprises at least one other fiber selected from natural plant fibers, natural animal fibers, artificial regenerated fibers, synthetic fibers and inorganic fibers.

[0115] Example

[0116] The present invention is further described in detail below using examples and comparative examples, but the present invention is not limited to these examples.

[0117] Example 1

[0118] The cut-resistant ultra-high molecular weight polyethylene fiber with reduced shedding in this embodiment is obtained by the following process:

[0119] Ultra-high molecular weight polyethylene with a viscosity average molecular weight of 4.8 million, low molecular weight polyethylene with a viscosity average molecular weight of 600,000, glass staple fibers, glass microspheres and decalin are mixed and swollen in a ratio of 100:10:5:2:1300. The intrinsic viscosity of ultra-high molecular weight polyethylene is 26.7 g / dl, and the intrinsic viscosity of polyethylene wax is 8.2 g / dl. The glass fiber is a one-dimensional linear structure with a diameter of up to 6 μm, an aspect ratio of 10, and a length of 60 μm. The average diameter of the glass microsphere particles is 1 μm. The glass fiber and glass microsphere are first treated with a silane coupling agent before feeding. After forming a suspension, it is sheared and dissolved by a screw, and extruded at 180°C and an extrusion speed of 4 m / min to form a spinning fine flow. After leaving the spinneret, the spinning fine flow is immediately desolventized to remove at least 98% of the solvent. The temperature is 150°C, the blowing height is 10m, and the air volume is 120m3 / h. During the solvent removal, the stretching speed is 16 m / min, the stretching ratio is 4, the stretching is performed simultaneously with the solvent removal, and the duration is 5 minutes to form the initial raw yarn. The initial raw yarn is stretched in 3 stages, the stretching temperature is 130° C., the stretching ratio is 13, and the finished yarn is made. The average diameter of the finished yarn core is 90% of the average diameter of the ultra-high molecular weight polyethylene fiber, and the unevenness of the predetermined thickness is 60%.

[0120] By observing the cross section of the ultra-high molecular weight polyethylene fiber of this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no bonding interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, but glass fibers and glass microsphere particles are basically not seen on the cross section of the skin layer.

[0121] Example 2

[0122] Same as Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 2.5 times that of the low molecular weight polyethylene.

[0123] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0124] Example 3

[0125] Same as Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 15 times that of the low molecular weight polyethylene.

[0126] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0127] Example 4

[0128] The same as Example 1, except that the average diameter of the finished fiber core is 65% of the average diameter of the ultra-high molecular weight polyethylene fiber.

[0129] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no bonding interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and many glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0130] Example 5

[0131] Same as Example 1, except that the stretching speed is 1.5 times the extrusion speed.

[0132] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0133] Example 6

[0134] Same as Example 1, except that the stretching speed is 15 times the extrusion speed.

[0135] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0136] Example 7

[0137] The same as Example 1, except that the solvent removal residence time is 1 min.

[0138] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0139] Example 8

[0140] The same as Example 1, except that the hard fibers are carbon fibers and the hard particles are ceramic particles.

[0141] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no bonding interface between the skin layer and the fiber core. Carbon fibers or ceramic particles can be seen in the cross section of the fiber core, and no carbon fibers or ceramic particles can be seen in the cross section of the skin layer.

[0142] Example 9

[0143] Same as Example 8, except that the ratio of ultra-high molecular weight polyethylene, low molecular weight polyethylene, carbon fiber, ceramic particles and decalin is 100:10:10:5:1300.

[0144] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no bonding interface between the skin layer and the fiber core. Carbon fibers or ceramic particles can be seen in the cross section of the fiber core, and fewer carbon fibers or ceramic particles can be seen in the cross section of the skin layer.

[0145] Example 10

[0146] The same as Example 9, except that the ratio of ultra-high molecular weight polyethylene, low molecular weight polyethylene, carbon fiber, ceramic particles and decalin is 100:10:3:0.5:1300.

[0147] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no bonding interface between the skin layer and the fiber core. Carbon fibers or ceramic particles can be seen in the cross section of the fiber core, and no carbon fibers or ceramic particles can be seen in the cross section of the skin layer.

[0148] Comparative Example 1

[0149] Same as Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 1.5 times that of the low molecular weight polyethylene.

[0150] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0151] Comparative Example 2

[0152] Same as Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 25 times that of the low molecular weight polyethylene.

[0153] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0154] Comparative Example 3

[0155] Same as Example 1, except that the stretching speed is 0.5 times the extrusion speed.

[0156] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0157] Comparative Example 4

[0158] Same as Example 1, except that the stretching speed is 25 times the extrusion speed.

[0159] The ratio is too large, resulting in many broken threads and poor yarn formation.

[0160] Comparative Example 5

[0161] The same as Example 1, except that low molecular weight polyethylene is not added, and a layer of polyurethane coating is applied on the surface after the finished yarn is made.

[0162] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is a bonding interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and medium glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0163] Comparative Example 6

[0164] The fiber is commercially available LY25 400D ultra-high molecular weight polyethylene fiber.

[0165] By observing the cross section of the ultra-high molecular weight polyethylene fiber of this example, no skin-core structure, no glass fiber and no particles are found.

[0166] Comparative Example 7

[0167] The same as Example 1, except that the gel spinning method is used. After the spinning solution exits the spinneret, the solvent is not removed immediately, but it is first cooled at a temperature of 30° C. and a cooling time of ≤1 min.

[0168] By observing the cross section of the ultra-high molecular weight polyethylene fiber in this example, it can be seen that a very thin skin layer is coated outside the fiber core, and there is no interface between the skin layer and the fiber core. Glass fibers or glass microsphere particles can be seen on the cross section of the fiber core, and more glass fibers and glass microsphere particles can be seen on the cross section of the skin layer.

[0169]

Claims

1. An ultra-high molecular weight polyethylene fiber having a core and a sheath covering at least a portion (preferably substantially all) of the surface of the core, wherein the core comprises hard fibers and optional hard particles dispersed in the core polyethylene, and the sheath comprises a reduced content of the hard fibers compared to the core.

2. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the viscosity-average molecular weight of the sheath polyethylene is 300,000-1.5 million (preferably 400,000-800,000), and the viscosity-average molecular weight of the core polyethylene is 2-20 times (preferably 3-10 times) the viscosity-average molecular weight of the sheath polyethylene.

3. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the content of the hard fiber is at most 50 parts by weight (preferably 3-10 parts by weight) relative to 100 parts by weight of the core polyethylene, the content of the hard particles is 0-20 parts by weight (preferably 0.5-5 parts by weight), and / or, relative to 100 parts by weight of the skin polyethylene, the content of the hard fiber is 0-30 parts by weight (preferably 0-3 parts by weight, more preferably substantially 0).

4. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the hard fiber is a one-dimensional linear structure having a diameter of at most 20 μm (preferably 3-10 μm), an aspect ratio of 3-1000 (preferably 5-50), a length of 10-2000 μm (preferably 30-300 μm), and / or an average diameter of the hard particles of not more than 20 μm (preferably 0.5-2 μm).

5. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the intrinsic viscosity of the core polyethylene is 2 to 20 times (preferably 3 to 10 times) the intrinsic viscosity of the sheath polyethylene.

6. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the intrinsic viscosity of the sheath polyethylene is no greater than 15 g / dl (preferably 4-10 g / dl), and the intrinsic viscosity of the core polyethylene is at least 10 g / dl (preferably 15-25 g / dl).

7. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the viscosity-average molecular weight of the sheath polyethylene is 300,000-1.5 million (preferably 400,000-800,000).

8. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the average diameter of the core is 70% to less than 100% (preferably 80% to less than 100%) of the average diameter of the ultra-high molecular weight polyethylene fiber.

9. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the sheath covers at least a portion of the surface of the core with a predetermined thickness, and the non-uniformity of the predetermined thickness exceeds 10% (such as exceeds 50%).

10. The ultra-high molecular weight polyethylene fiber of claim 1, wherein the sheath is in-situ generated by a spinning method, or the sheath has no bonding interface with the core.

11. A method for producing ultra-high molecular weight polyethylene fiber, comprising the following steps: 1) mixing ultra-high molecular weight polyethylene, low molecular weight polyethylene, hard fibers, solvent and optional hard particles to prepare a spinning solution, 2) extruding the spinning solution through a spinneret to form a spinning fine stream, 3) while stretching the spinning stream, removing at least a portion (e.g., at least 50 wt%, preferably at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% or at least 97 wt%) of the solvent from the spinning stream to obtain the ultra-high molecular weight polyethylene fiber (referred to as spun fiber), The ratio of the drawing speed to the extrusion speed of the spinning fine stream is 1-20 (preferably 2-10).

12. The manufacturing method according to claim 11, wherein in step 2), the extrusion temperature is 150-220°C (preferably 160-200°C), and the extrusion speed is 2-20 m / min (3-10 m / min).

13. The manufacturing method according to claim 11, wherein the step 3) is immediately performed after the spinning stream leaves the spinneret.

14. The manufacturing method according to claim 11, wherein in step 3), the operating conditions include: The temperature is 70-180°C (preferably 140-160°C), the blowing height is not less than 0.2m (preferably 5-15m), and the air volume is 50-180m3 / h (preferably 90-150m3 / h).

15. The manufacturing method according to claim 11, wherein in step 3), the stretching speed is not less than 2 m / min (preferably 5-20 m / min), and the stretching ratio is not less than 2 (preferably 3-10).

16. The manufacturing method according to claim 11, wherein in step 3), the stretching and the solvent removal are carried out simultaneously, and the duration is not less than 2 minutes (preferably 3-10 minutes).

17. A fabric comprising the ultra-high molecular weight polyethylene fiber of claim 1, or made of the ultra-high molecular weight polyethylene fiber of claim 1, or made of the ultra-high molecular weight polyethylene fiber of claim 1 and other fibers.

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