Polyethylene fibers with very high molecular weight and very high shear strength and their preparation process

Abstract

This technology relates to polyethylene fibers with very high molecular weight and very high shear strength, including: a polyethylene matrix with very high molecular weight and carbon fiber powder particles dispersed therein. The content of carbon fiber powder particles is 0.25 to 10% by weight. This innovation is more related to the method of preparing polyethylene fibers with very high molecular weight and very high shear strength and a cut-resistant glove woven from them. This test proves that the glove woven from ultra-high molecular weight polyethylene fibers with very high shear resistance is soft and comfortable and does not feel itchy. According to the EN388-2003 standard test, the cut resistance grade level varies from 4 to 5. Compared with the use of other existing high-hardness inorganic reinforcing materials, the production process of ultra-high molecular weight polyethylene fibers with very high shear resistance in current technology causes relatively less abrasion on the equipment. Additionally, cut-resistant woven gloves are more durable and maintain higher cut resistance performance than other gloves.

Description

Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber is currently the industrially produced fiber material with the highest specific strength. It possesses excellent properties such as high strength, high modulus, abrasion resistance, and chemical corrosion resistance, and is widely used in national defense, marine engineering cables, and personal protective equipment. With the deepening of military-civilian integration, the application of UHMWPE fiber in the civilian market is gradually increasing, with cut-resistant gloves becoming increasingly dominant. Currently, the most commonly used protective gloves made of 400D UHMWPE fiber have a cut rating of at most EN388-2003 standard level 3, and this is highly unstable, increasingly failing to meet the needs of actual working environments for cut protection.

[0003] To improve the cut resistance of gloves, a common method is to blend materials such as fiberglass and steel wire with ultra-high molecular weight polyethylene fibers to achieve an ultra-high cut resistance level. While this method can improve the cut resistance of gloves, it suffers from several drawbacks. Steel wire is relatively stiff (making it difficult to wear and uncomfortable), while fiberglass is brittle and prone to breakage and exposure. Furthermore, the gloves have a poor feel and low wearing comfort. Additionally, fiberglass burrs can cause secondary injuries such as itching, punctures, and scratches to the hands, making it impossible to achieve a balance between protective performance and comfort.

[0004] In addition, some industry professionals have proposed adding inorganic high-hardness materials to high-molecular-weight polyethylene powder to produce high-molecular-weight polyethylene nascent fibers in order to enhance the cut resistance of polyethylene fibers. Although this method can indeed improve the cut resistance of polyethylene fibers, there are still two significant problems: (1) These inorganic high-hardness materials are quite hard, which not only causes greater wear and tear on the preparation equipment, requiring frequent replacement of parts of the equipment, increasing equipment investment, but also affects production efficiency; (2) In actual use, it has also been found that these high-hardness materials have low flexibility and are prone to puncturing the polyethylene fiber matrix during repeated use, causing damage to the surface of the polyethylene fibers and rendering the high-strength cut resistance ineffective.

[0005] Summary of the Invention

[0006] (I) Technical problems to be solved

[0007] In view of this, the inventors aim to provide an ultra-high cut-resistant ultra-high molecular weight polyethylene fiber and its preparation method to overcome the problems existing in the prior art. The ultra-high cut-resistant ultra-high molecular weight polyethylene fiber can be woven into cut-resistant gloves or cut-resistant protective clothing, achieving high-strength protective performance and good wearing comfort, while avoiding wear and damage to production equipment, saving production costs, and extending the performance life of cut-resistant gloves or cut-resistant protective clothing.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] One aspect of this application provides an ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, comprising an ultra-high molecular weight polyethylene matrix and carbon fiber powder particles dispersed therein, wherein the content of the carbon fiber powder particles is 0.25 to 10 wt%.

[0011] Typically, but not limitingly, the carbon fiber powder content in the ultra-high molecular weight polyethylene matrix is ​​0.25 wt%, 0.5 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, 8.0 wt%, 8.5 wt%, 9.0 wt%, 9.5 wt%, or 10.0 wt%.

[0012] If the carbon fiber powder content is too high, the polyethylene matrix will be too low, which will make the resulting polyethylene fiber less spinnable (and more prone to breakage during the spinning process). If the carbon fiber powder content is too low, the intended purpose of increasing the cut resistance will not be achieved.

[0013] This invention also relates to a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, comprising:

[0014] S1: Carbon fiber powder is mixed and emulsified with a first solvent and a surfactant to prepare carbon fiber powder emulsion;

[0015] S2: The carbon fiber powder emulsion and ultra-high molecular weight polyethylene powder with a molecular weight of 200,000 to 6 million are dispersed together in a second solvent to prepare a mixture.

[0016] S3: The mixture is co-extruded through an extruder, cooled and shaped in a coagulation bath to obtain nascent fibers, and the nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to obtain ultra-high cut-resistant ultra-high molecular weight polyethylene fibers.

[0017] Typically, but not limited to, ultra-high molecular weight polyethylene has a molecular weight of 200,000, 400,000, 600,000, 800,000, 1,000,000, 1,200,000, 1,400,000, 1,600,000, 1,800,000, 2,000,000, 2,200,000, 2,400,000, 2,600,000, 2,800,000, 3,000,000, 3,200,000, 3,400,000, 3,600,000, 3,800,000, 4,000,000, 4,200,000, 4,400,000, 4,600,000, 4,800,000, 5,000,000, 5,200,000, 5,400,000, 5,600,000, 5,800,000, or 6,000,000.

[0018] In a preferred embodiment of the present invention, the carbon fiber powder particles have a diameter of 0.1-10 μm and a length of 0.1-100 μm. Further, the carbon fiber powder particles are long rod-shaped particles with a length greater than their diameter; more preferably, the length is 20-60 μm. Typically, but not limitingly, the carbon fiber powder particles have a length of 20-30 μm, 30-40 μm, 40-50 μm, or 50-60 μm.

[0019] In a preferred embodiment of the present invention, the main component of the carbon fiber powder is microcrystalline graphite, which can be produced by crushing waste carbon fiber or by cutting carbon fiber filaments.

[0020] In a preferred embodiment of the present invention, the carbon fiber powder is pre-treated to activate the surface of the carbon fiber powder particles. This improves the interfacial compatibility and / or wettability of the carbon fiber powder with solvents and ultra-high molecular weight polyethylene powder, thereby obtaining ultra-high molecular weight polyethylene fibers with uniform material distribution and better, more stable performance.

[0021] In a preferred embodiment of the present invention, the surface treatment method is any one or a combination of the following: gas-phase oxidation, liquid-phase oxidation, catalytic oxidation, coupling agent coating, polymer coating, and plasma (electrolysis) treatment. Surface treatment using one of the aforementioned methods imparts a weakly polar surface to the carbon fiber particles, preventing agglomeration of the carbon fibers in the solvent and improving their dispersion in the solvent. This allows for more uniform dispersion within the ultra-high molecular weight polyethylene matrix and enables a tighter bond with the ultra-high molecular weight polyethylene matrix, preventing carbon fiber peeling and improving the uniformity and aging properties of the ultra-high cut-resistant ultra-high molecular weight polyethylene fiber.

[0022] In a preferred embodiment of the present invention, the mass ratio of the ultra-high molecular weight polyethylene, carbon fiber powder, and solvent is 10-40:0.1-1:100; the mass of the solvent refers to the sum of the masses of the first solvent and the second solvent.

[0023] According to the above mass ratio, the resulting mixture is a paste, and the mixture contains sufficient carbon fiber powder to provide good cut resistance. It should be noted that in this application, the first solvent and the second solvent differ only in the steps of solvent application and do not represent that the first solvent and the second solvent are different. In other words, the first solvent and the second solvent can be the same solvent or different solvents.

[0024] Preferably, the first solvent and the second solvent are both selected from one or more of white oil, mineral oil, vegetable oil, paraffin oil and decahydronaphthalene.

[0025] In a preferred embodiment of the present invention, the ultra-high molecular weight polyethylene has a molecular weight of 2-5 million.

[0026] The higher the molecular weight of ultra-high molecular weight polyethylene (UHMWPE), the higher its cut resistance and mechanical strength. However, if the molecular weight is too high, the viscosity will be too great, making it difficult to extrude into fibers, resulting in poor fiber formation and requiring high-performance equipment with significant wear and tear. Through repeated experiments, UHMWPE fibers with a molecular weight of 2-5 million exhibited the best performance in all aspects and resulted in low equipment wear.

[0027] In a preferred embodiment of the present invention, the extruder is a twin-screw extruder, and the temperature of each zone of the twin screw is controlled between 100-300 ℃.

[0028] In a preferred embodiment of the present invention, the surfactant is an alkylolamide (6502), which is a mild nonionic surfactant obtained by condensation reaction of coconut oil or palm kernel oil and diethanolamine, or the surfactant is an alkylolamide phosphate ester. These surfactants have solubilizing and emulsifying effects, antistatic conditioning effects, and are non-irritating to the skin, and are commonly used in detergents, fabric conditioners, etc. Of course, the surfactant is not limited to those listed above, but any surfactant that can emulsify and increase the dispersion of carbon fiber powder in a solvent is acceptable, such as stearic acid, sodium dodecylbenzene sulfonate, alkyl glucoside (APG), triethanolamine, fatty acid glycerides, fatty acid sorbitan (Span), polysorbate (Tween), sodium dioctyl succinate sulfonate (aloxo-OT), sodium dodecylbenzene sulfonate, sodium glycocholate, etc.

[0029] This invention relates to an ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which is prepared by the preparation method described in any of the above embodiments.

[0030] The present invention also relates to an ultra-high cut-resistant glove or cut-resistant garment, comprising a woven fabric made of ultra-high cut-resistant ultra-high molecular weight polyethylene fiber prepared by any of the above embodiments or preparation methods.

[0031] Carbon fiber (CF) is a type of microcrystalline graphite material, a new type of fiber material with a carbon content of over 95% and high strength and high modulus. Carbon fiber is "flexible on the outside and rigid on the inside," lighter than aluminum but stronger than steel, and possesses corrosion resistance and high modulus. It combines the inherent properties of carbon materials with the flexibility and processability of textile fibers, making it a new generation of reinforcing fibers. Its main characteristics include: (1) combining the flexibility and processability of textile fibers; (2) tensile strength above 3500 MPa; and (3) tensile modulus of elasticity from 230 to 430 GPa.

[0032] Plasma surface treatment: Using a plasma surface processor, the low-temperature plasma, in a non-thermodynamically equilibrium state, provides high-energy electrons that can break the chemical bonds of molecules on the material surface, increasing the chemical reactivity of particles (greater than thermal plasma). Meanwhile, the temperature of neutral particles is close to room temperature. These advantages provide suitable conditions for surface modification of heat-sensitive polymers. Through low-temperature plasma surface treatment, various physical and chemical changes occur on the material surface. The surface is cleaned, removing hydrocarbon contaminants such as grease and additives; it may also become roughened through etching, form a dense cross-linked layer, or introduce oxygen-containing polar groups (hydroxyl, carboxyl groups). These groups promote the adhesion of various coating materials, optimizing applications in adhesives and paints.

[0033] (III) Beneficial Effects

[0034] The beneficial effects of this invention are:

[0035] (1) This invention disperses carbon fiber powder as an additive in an ultra-high molecular weight polyethylene (UHMWPE) fiber matrix material to obtain an UHMWPE fiber with ultra-high cut resistance. Compared with the prior art, which uses materials such as glass fiber and steel wire to blend and weave UHMWPE fiber, the gloves or glove blanks woven from the UHMWPE fiber with ultra-high cut resistance of this invention have better wearing comfort, such as being softer, having a better touch, and being free from problems such as burrs, itching, and scratches, and are easier to wear.

[0036] (2) Compared to other inorganic high-hardness materials such as boron nitride and tungsten carbide as reinforcing additives, the carbon fiber powder used in this invention, when co-extruded with ultra-high molecular weight polyethylene powder to manufacture nascent ultra-high molecular weight polyethylene fibers, not only does not weaken the cut resistance of the nascent ultra-high molecular weight polyethylene fibers due to the lower hardness and higher toughness of the carbon fiber, but also causes less wear on equipment, reducing equipment and production costs, and does not negatively affect production efficiency. In addition, the carbon fiber powder has strong flexibility and is not easily punctured on the surface of the ultra-high molecular weight polyethylene fiber matrix, thus preventing it from detaching and causing fiber damage. Therefore, the carbon fiber powder can be retained in the polyethylene fiber matrix for a longer period of time, giving the high-cut-resistant polyethylene fiber a more durable cut resistance performance.

[0037] (3) Further, in preparing ultra-high molecular weight polyethylene fiber with ultra-high cut resistance, the carbon fiber powder is first subjected to surface activation treatment to improve the dispersion of the carbon fiber powder and prevent agglomeration in solvent dispersion. Then, the carbon fiber powder is first made into an additive emulsion, and then dispersed together with ultra-high molecular weight polyethylene powder in a solvent to form a mixture. The nascent fiber is obtained by co-extrusion using a screw extruder, so that the carbon fiber powder can be uniformly and stably integrated into the ultra-high molecular weight polyethylene fiber matrix, and combined with the ultra-high molecular weight polyethylene fiber to form a stable body. The ultra-high molecular weight polyethylene fiber acts as a solid dispersant for the carbon fiber powder, thus obtaining ultra-high molecular weight polyethylene fiber with better cut resistance, more uniformity and better quality.

[0038] In summary, the ultra-high cut-resistant ultra-high molecular weight polyethylene fiber of this invention significantly improves the cut-resistant performance of polyethylene fiber, and the cut resistance level of gloves and other fabrics woven from it can consistently reach EN388-2003 standard level 5. More importantly, the ultra-high cut-resistant ultra-high molecular weight polyethylene fiber produced according to this invention does not require blending with materials such as steel wire or glass fiber for reinforcement, and the resulting protective gloves are soft, lightweight, and flexible, reducing fatigue during prolonged wear, thus achieving a balance between ultra-high cut resistance and wearing comfort. Detailed Implementation

[0039] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below through specific embodiments.

[0040] The overall concept of this invention is as follows: a certain amount of carbon fiber powder is used as one of the raw materials for preparing ultra-high molecular weight polyethylene (UHMWPE) nascent fibers. The carbon fiber powder particles are uniformly and stably fused into the UHMWPE fiber matrix, forming a stable bond with the UHMWPE fibers to obtain ultra-high cut-resistant UHMWPE fibers. Compared to other high-hardness inorganic reinforcing materials, carbon fiber possesses unparalleled "flexible exterior, rigid interior" characteristics. It can not only replace other high-hardness inorganic reinforcing materials to give UHMWPE fibers high cut-resistant performance, but also has significant advantages in reducing equipment wear and preventing the UHMWPE fiber matrix from being punctured during repeated use, thus reducing cut-resistant performance.

[0041] Preferably, the specific preparation method of the present invention can be carried out according to the following steps:

[0042] (1) Prepare carbon fiber powder

[0043] The carbon fiber powder particles are preferably rod-shaped, with a diameter of 0.1-10 μm and a length of 0.1-100 μm; more preferably, the length is 20-60 μm.

[0044] The main component of carbon fiber powder is microcrystalline graphite, which can be produced by crushing and sieving waste carbon fibers, or by cutting carbon fiber filaments.

[0045] (2) Surface treatment of carbon fiber powder

[0046] The main purpose of surface treatment is to activate the surface of carbon fiber powder particles. The methods that can be used include: gas phase oxidation, liquid phase oxidation, catalytic oxidation, coupling agent coating, polymer coating, and plasma treatment.

[0047] After activation treatment, carbon fiber particles develop a weak polarity on their surface, which improves their dispersion in solvents, prevents carbon fiber powder agglomeration, and further enhances the dispersion uniformity, interfacial fusion, and / or wettability of carbon fiber particles in ultra-high molecular weight polyethylene matrix, thereby obtaining ultra-high cut-resistant polyethylene fibers with better performance.

[0048] (3) Emulsion for making carbon fiber powder

[0049] A portion of solvent is taken, and the treated carbon fiber powder and surfactant are added to this portion of solvent. High-shear emulsification is then performed to prepare a carbon fiber powder emulsion. The solvent is selected from one or more of white oil, mineral oil, vegetable oil, paraffin oil, and decahydronaphthalene.

[0050] (4) Preparation of mixture: Add ultra-high molecular weight polyethylene powder with a molecular weight of 200,000 to 6,000,000 (preferably 400,000 to 800,000) and carbon fiber powder emulsion to the remaining solvent to prepare a mixture.

[0051] The mass ratio of ultra-high molecular weight polyethylene: carbon fiber emulsion: solvent is (10-40): (0.1-1): 100.

[0052] The solvent is selected from one or more of white oil, mineral oil, vegetable oil, paraffin oil and decahydronaphthalene.

[0053] (5) Prevent cutting polyethylene fibers

[0054] The mixture is co-extruded through a twin-screw extruder and cooled in a coagulation bath to obtain nascent fibers. The temperature of each zone of the twin screw is controlled between 100-300 ℃. The nascent fibers are then extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high cut-resistant ultra-high molecular weight polyethylene fibers.

[0055] The technical effects of the present invention will be further explained below with reference to specific embodiments.

[0056] Example 1

[0057] This embodiment provides a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which includes the following steps:

[0058] (1) Take 750g of carbon fiber powder with a length of 10-20um and perform surface treatment on the carbon fiber powder with plasma for 1h.

[0059] (2) Weigh 100kg of white oil, take out 5kg, add the treated carbon fiber powder and 5ml of surfactant (disodium lauryl sulfosuccinate) to the 5kg of white oil for high shear emulsification. The shear rate is 2800r / min and the emulsification time is 30min to obtain carbon fiber emulsion.

[0060] (3) Take 15 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 2 million and an average particle size of 100 μm. Add the 15 kg of ultra-high molecular weight polyethylene powder and the emulsified carbon fiber emulsion to the remaining 95 kg of white oil and mix evenly for 1 hour to obtain the mixture.

[0061] (4) The well-mixed mixture is co-extruded by a twin-screw extruder and cooled and shaped in a coagulation bath to obtain nascent fibers. The obtained nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high molecular weight polyethylene ultra-high cut-resistant fibers, wherein the carbon fiber dispersion concentration in ultra-high molecular weight polyethylene is 5%.

[0062] Cut-resistant gloves made from the aforementioned fibers are soft to the touch, non-prickly, and comfortable to wear. They are tested according to EN388-2003 and have a cut resistance rating of 5.

[0063] Example 2

[0064] This embodiment provides a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which includes the following steps:

[0065] (1) Take 800g of carbon fiber powder with a length of 20-30um and perform surface treatment on the carbon fiber powder with plasma for 1h.

[0066] (2) Weigh 100kg of white oil, take out 5kg, add the treated carbon fiber powder and 15ml of surfactant (disodium cocoyl ethanolamide sulfosuccinate monoester DMSS) to the 5kg of white oil for high shear emulsification. The shear rate is 2800r / min and the emulsification time is 30min to obtain carbon fiber powder emulsion.

[0067] (3) Take 20 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 3 million and an average particle size of 100 μm. Add the 20 kg of ultra-high molecular weight polyethylene powder and the emulsified carbon fiber powder emulsion to the remaining 95 kg of white oil and mix evenly for 1 hour to obtain the mixture.

[0068] (4) The well-mixed mixture is co-extruded by a twin-screw extruder and cooled and shaped in a coagulation bath to obtain nascent fibers. The obtained nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high molecular weight polyethylene ultra-high cut-resistant fibers, wherein the carbon fiber dispersion concentration in ultra-high molecular weight polyethylene is 4%.

[0069] Cut-resistant gloves made from the aforementioned fibers are soft to the touch, non-prickly, and comfortable to wear. They are tested according to EN388-2003 and have a cut resistance rating of 5.

[0070] Example 3

[0071] This embodiment provides a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which includes the following steps:

[0072] (1) Take 1000g of carbon fiber powder with a length of 30-60um and perform surface treatment on the carbon fiber powder with plasma for 1h.

[0073] (2) Weigh 100kg of white oil, take out 5kg, add the treated carbon fiber powder and 10ml of surfactant (monolaroyl phosphate MAP) to the 5kg of white oil for high shear emulsification. The shear rate is 2800r / min and the emulsification time is 30min to obtain carbon fiber powder emulsion.

[0074] (3) Take 10 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 2.6 million and an average particle size of 100 μm. Add the 10 kg of ultra-high molecular weight polyethylene powder and the emulsified carbon fiber powder emulsion to the remaining 95 kg of white oil and mix evenly for 1 hour to obtain the mixture.

[0075] (4) The well-mixed mixture is co-extruded by a twin-screw extruder and cooled and shaped in a coagulation bath to obtain nascent fibers. The obtained nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high molecular weight polyethylene ultra-high cut-resistant fibers, wherein the carbon fiber dispersion concentration in ultra-high molecular weight polyethylene is 10%.

[0076] Cut-resistant gloves made from the aforementioned fibers are soft to the touch, non-prickly, and comfortable to wear. They are tested according to EN388-2003 and have a cut resistance rating of 5.

[0077] Example 4

[0078] This embodiment provides a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which includes the following steps:

[0079] (1) Take 750g of carbon fiber powder with a length of 20-30um and perform surface treatment on the carbon fiber powder with plasma for 1h.

[0080] (2) Weigh 100kg of white oil, take out 5kg, add the treated carbon fiber powder and 10ml of surfactant (potassium monododecyl phosphate MAPK) to the 5kg of white oil for high shear emulsification. The shear rate is 2800r / min and the emulsification time is 30min to obtain carbon fiber powder emulsion.

[0081] (3) Take 20 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 3.6 million and an average particle size of 100 μm. Add the 20 kg of ultra-high molecular weight polyethylene powder and the emulsified carbon fiber powder emulsion to the remaining 95 kg of white oil and mix evenly for 1 hour to obtain the mixture.

[0082] (4) The well-mixed mixture is co-extruded through a twin-screw extruder and cooled and shaped in a coagulation bath to obtain nascent fibers. The obtained nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high molecular weight polyethylene ultra-high cut-resistant fibers, wherein the carbon fiber dispersion concentration in ultra-high molecular weight polyethylene is 3.75%.

[0083] Cut-resistant gloves made from the aforementioned fibers are soft to the touch, non-prickly, and comfortable to wear. They are tested according to EN388-2003 and have a cut resistance rating of 5.

[0084] Example 5

[0085] This embodiment provides a method for preparing ultra-high cut-resistant ultra-high molecular weight polyethylene fiber, which includes the following steps:

[0086] (1) Take 600g of carbon fiber powder with a length of 40-60um and perform surface treatment on the carbon fiber powder with plasma for 1h.

[0087] (2) Weigh 100kg of vegetable oil, take out 5kg, add the treated carbon fiber powder and 10ml of surfactant (potassium lauryl ether phosphate MAEPK) to the 5kg of vegetable oil for high shear emulsification. The shear rate is 2800r / min and the emulsification time is 30min to obtain carbon fiber powder emulsion.

[0088] (3) Take 30 kg of ultra-high molecular weight polyethylene powder with a molecular weight of 400,000 and an average particle size of 100 μm. Add the 30 kg of ultra-high molecular weight polyethylene powder and the emulsified carbon fiber powder emulsion to the remaining 95 kg of vegetable oil and mix evenly for 1 hour to obtain the mixture.

[0089] (4) The well-mixed mixture is co-extruded through a twin-screw extruder and cooled and shaped in a coagulation bath to obtain nascent fibers. The obtained nascent fibers are extracted, dried, and subjected to multi-stage hot stretching to produce ultra-high molecular weight polyethylene ultra-high cut-resistant fibers, wherein the carbon fiber dispersion concentration in ultra-high molecular weight polyethylene is 2%.

[0090] Cut-resistant gloves made from the aforementioned fibers are soft to the touch, non-prickly, and comfortable to wear. They are tested according to EN388-2003 and have a cut resistance rating of 4.

[0091] Example 6

[0092] This embodiment is based on Example 1, but without any surface treatment of the carbon fibers, which are agglomerated in the emulsion. Other conditions and processing procedures are the same as in Example 1, resulting in ultra-high molecular weight polyethylene ultra-high cut-resistant fiber, with the carbon fibers dispersed at a concentration of 5% in the ultra-high molecular weight polyethylene. Carbon fibers without surface activation treatment are prone to agglomeration, resulting in poor spinnability of the resulting fibers, and the cut-resistant performance of gloves woven from this fiber is also unstable.

[0093] Comparative Example 1

[0094] In Example 1, the carbon fiber was replaced with 750g of boron nitride with a length of 10-20µm. Other conditions and procedures were the same as in Example 1, resulting in ultra-high molecular weight polyethylene (UHMWPE) ultra-high cut-resistant fiber with a boron nitride dispersion concentration of 5% in the UHMWPE. The resulting fiber filaments exhibited poor spinnability. Gloves woven from this fiber showed a rapid decline in cut resistance with prolonged use, and the glove surface became rough, hard, and lacked both hand feel and wearing comfort.

[0095] Comparative Example 2

[0096] In Example 1, the carbon fiber was replaced with 750g of tungsten carbide with a length of 10-20µm. Other conditions and processing procedures were the same as in Example 1, resulting in ultra-high molecular weight polyethylene (UHMWPE) ultra-high cut-resistant fiber with a tungsten carbide dispersion concentration of 5% in UHMWPE. The resulting fiber filaments had poor spinnability. Gloves woven from this fiber showed a rapid decline in cut resistance with prolonged use, and the glove surface became rough, hard, and had poor feel and wearing comfort.

[0097] The ultra-high cut-resistant ultra-high molecular weight polyethylene fibers prepared in Examples 1-6 and Comparative Examples 1-2 were woven into 13-needle protective gloves. After being worn and used by workers in the same position and performing the same operation for 1 day (1d) and 20 days (20d), the performance of the gloves was tested. The test results are shown in the table below:

[0098]

[0099] As can be seen from the test results of the above embodiments, the gloves and other fabrics woven from the ultra-high cut-resistant ultra-high molecular weight polyethylene fiber of the present invention can indeed stably reach the cut resistance level of EN388-2003 standard 4-5. More importantly, the ultra-high cut-resistant ultra-high molecular weight polyethylene fiber produced according to the present invention does not need to be blended with materials such as steel wire or glass fiber for reinforcement, and the resulting protective gloves are soft, lightweight, sensitive, and comfortable to wear, and do not cause fatigue even after long-term wear.

[0100] Furthermore, a comparison between Examples 1-5 and Example 6 shows that the test results of Example 6 are not very stable, mainly due to the uneven distribution of carbon fibers in the ultra-high molecular weight polyethylene matrix.

[0101] Compared with Comparative Examples 1-2, the high-cut-resistant gloves of Comparative Examples 1-2 showed comparable cut-resistance values ​​and levels to those of Examples 1-6 after approximately one day of use. However, after 20 days of use, the cut-resistance performance of the gloves of Comparative Examples 1-2 decreased drastically, and the surface became rough, the gloves became harder, and the comfort was poor. Example 6 involved sampling and testing at three different locations to obtain a range of values. The gloves of Comparative Examples 1-2 failed primarily because repeated bending and twisting during 20 days of use caused the high-hardness inorganic reinforcing material, lacking flexibility, to directly puncture the polyethylene matrix, resulting in surface damage and burrs. The partial detachment of the inorganic reinforcing material also weakened the cut-resistance performance. Conversely, the polyethylene gloves of this invention, reinforced with carbon fiber, exhibited exceptional durability. After repeated use, their cut-resistance performance was almost equivalent to that of the newly manufactured product, and they were soft and smooth, providing a good wearing experience.

[0102] This demonstrates that while the inorganic high-hardness reinforcing material used in Comparative Example 1 has high hardness, its poor flexibility makes it prone to piercing the surface of the ultra-high molecular weight polyethylene fiber matrix, causing damage and partial shedding of the high-hardness reinforcing material, resulting in a rapid decline in cut resistance. Furthermore, the present invention uses carbon fiber as an additive for cut resistance reinforcement, and the cut-resistant gloves prepared accordingly exhibit cut resistance comparable to those made with inorganic high-hardness materials such as boron nitride and tungsten carbide.

[0103] Furthermore, according to the applicant's experimental preparation research over the past six months, it was found that when the inorganic high-hardness additives in Comparative Examples 1-2 were used to enhance the cut resistance of high molecular weight polyethylene fibers, the high molecular weight polyethylene fibers caused severe wear on equipment such as the screw of the extruder during the preparation process, resulting in very rapid equipment depreciation and significant wear on the equipment. However, after replacing these inorganic high-hardness reinforcing materials with carbon fiber in this invention, the wear on the equipment is almost equivalent to that caused by simply producing ultra-high molecular weight polyethylene fibers in the past.

Claims

Request for amendment and change of the claims of the patent application with application number 1399501400003007334 based on Article 23 of the Executive Regulations of the Law on Patents, Industrial Designs and Trademarks. In accordance with the present amendment, the claims are amended and modified as follows: Claim number one: Very high molecular weight polyethylene fibers and very high shear strength include: a very high molecular weight polyethylene matrix and carbon fiber powder particles dispersed therein, in which the content of carbon fiber powder particles is 0.25 to 10% by weight, and the carbon fiber powder particles are activated by plasma action. Claim number two: A method for preparing ultra-high molecular weight polyethylene with very high shear strength includes the following steps: S1: preparing carbon fiber powder particles by pre-treatment with plasma to activate the surfaces of the carbon fiber powder particles; S2: mixing and emulsifying the carbon fiber powder particles with a first solvent and a surfactant to obtain a carbon fiber powder emulsion; S3: dispersing the carbon fiber powder emulsion with ultra-high molecular weight polyethylene powder with a molecular weight of 200,000 to 600,000 in a second solvent to obtain a mixture; and S4: mixing and extruding the mixture through an extruder, cooling and molding in a coagulation bath to obtain new fibers, extracting, drying and multi-stage hot drawing of the new fibers to obtain ultra-high molecular weight polyethylene fibers with very high shear strength, in which the content of the carbon fiber powder particles is 0.25 to 10% by weight. Claim number three: The method of claim 2, wherein the diameter of the carbon fiber powder particles is 0.1 to 10 micrometers and the length is 0.1 to 100 micrometers; the preferred shape of the carbon fiber powder particles is a long rod and the length is greater than the diameter. Claim number four: Claim number 3, wherein the main component of the carbon fiber powder particles is microcrystalline graphite, and wherein the carbon fiber powder particles are obtained by crushing waste carbon fibers. Claim number five: The method of claim 2 or 3, wherein the mass ratio of the very high molecular weight polyethylene, carbon fiber powder, and solvent is (10-40):(0.1-1):100, and the mass of the solvent is equal to the sum of the masses of the first solvent and the second solvent. Claim number six: The method of claim 2, wherein the molecular weight of the ultra-high molecular weight polyethylene is 200,000 to 500,000. Claim number seven: The method of claim 2, wherein the extruder is a twin-screw extruder and the temperature of each zone of the twin-screw extruder is controlled at 100 to 300 degrees Celsius.