Sheath-core composite polyethylene fiber and method for manufacturing the same

Abstract

To provide a sheath-core composite polyethylene fiber in which the cut resistance of the sheath-core composite polyethylene fiber is significantly improved and the problems of powder falling, discoloration, and equipment damage when the sheath-core composite polyethylene fiber is used in a subsequent process are effectively solved, and a method for manufacturing the same.SOLUTION: There is provided a sheath-core composite polyethylene fiber, comprising: a fiber core layer; and a fiber sheath layer. The fiber sheath layer wraps around the fiber core layer. The fiber sheath layer contains an ultra-high molecular weight polyethylene A, and the fiber core layer contains an ultra-high molecular weight polyethylene B, a first auxiliary agent, and a second auxiliary agent. The first auxiliary agent includes mineral fibers. The second auxiliary agent contains at least one of inorganic ultrafine powder and graphene. The second auxiliary may or may not include a color paste and an antioxidant.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and specifically relates to sheath-core composite polyethylene fibers and a manufacturing method thereof.

Background Art

[0002] Ultra-high molecular weight polyethylene fibers are high-performance chemical fibers with ultra-high strength and ultra-high elastic modulus. Their products are widely used in the military field (body armor, bulletproof helmets, other personal protective equipment, tanks, ships, helicopters, other armored protective equipment, etc.) and industrial fields (ship ropes, cultured fish, sports goods, radomes, etc.). Conventional ultra-high molecular weight polyethylene fibers have long molecular chains and intense entanglement, so the cut resistance grade of the main body is generally only about grade 2 (when glass fibers, steel wires, etc. are blended and woven into ultra-high molecular weight polyethylene fibers, the comfort of the blended fibers deteriorates). In addition, ultra-high molecular weight polyethylene fibers are difficult to dye and have poor dye fastness because of their non-polar and highly crystalline molecular structure.

[0003] In the prior art, regarding the research on ultra-high molecular weight polyethylene fibers, for example, Patent Application CN109322006A discloses colored high-strength polyethylene fibers and a manufacturing method thereof. By filling components such as surface-modified nanoboron fibers, the cut resistance of ultra-high molecular weight polyethylene fibers can be improved to a certain extent without sacrificing comfort, and by using a technology that combines dope dyeing and sheath-core composite technology, dyeing can be facilitated and a certain degree of dye fastness can be improved. However, the sheath-core composite polyethylene fibers of the prior art still have problems such as being prone to powder falling and color fading when applied in subsequent use processes, being prone to wearing the equipment in subsequent processes, and there are also limitations in improving the cut resistance.

[0004] Therefore, in order to solve the above technical problems, new technical means are needed.

Summary of the Invention

[0005] The object of the present invention is to provide a sheath-core composite polyethylene fiber and a method for producing the same, thereby solving the technical problems in the prior art described above, which include the fact that sheath-core composite polyethylene fibers tend to shed powder and fade in color when applied to subsequent processes, causing wear on equipment in subsequent processes and limiting the improvement of cut resistance.

[0006] To achieve the above objectives, the present invention employs the following technical means.

[0007] A sheath-core composite polyethylene fiber comprising a fiber core layer and a fiber sheath layer, wherein the fiber sheath layer encloses the fiber core layer, the fiber sheath layer contains ultra-high molecular weight polyethylene A, the fiber core layer contains ultra-high molecular weight polyethylene B, a first additive and a second additive, the first additive contains mineral fibers, the second additive contains at least one of inorganic ultrafine powder and graphene, and the second additive may or may not contain a color sizing agent and an antioxidant. The amounts used for the first and second additives are 0.1-60% and 0.1-30% of the total mass of ultra-high molecular weight polyethylene B, the first additive and the second additive, respectively. Specifically, the amounts used for the inorganic ultrafine powder, graphene, color sizing agent and antioxidant are 0-20%, 0-10%, 0-20%, and 0-2% of the total mass of ultra-high molecular weight polyethylene B, the first additive and the second additive, respectively. The mineral fiber is one of glass fibers, ceramic fibers, and carbon fibers, or a combination thereof. The inorganic ultrafine powder is one of aluminum, titanium, silicon, boron, carbides, nitrides, and zirconium oxides, or a combination thereof, with an average radius of 0.1 to 300 μm. The weight-average molecular weight of ultra-high molecular weight polyethylene A and ultra-high molecular weight polyethylene B is both 1 to 4 million.

[0008] The present invention further provides a method for producing the sheath-core composite polyethylene fiber. This production method includes the following steps. S1: Mineral fibers are added to solvent A, pre-treated by dispersion and stirring, and then sanded to produce the first auxiliary agent. Here, solvent A is white oil. S2: At least one of inorganic ultrafine powder and graphene is added to solvent B, and a color sizing agent and an antioxidant may or may not be added. After the addition is complete, the mixture is pretreated by dispersion and stirring, and then sanded to produce the second auxiliary agent. Here, solvent B is white oil. S3: Ultra-high molecular weight polyethylene B, the first auxiliary agent, and the second auxiliary agent are added to solvent C and mixed uniformly. The mixture is then introduced into a twin-screw extruder, heated, and extruded to dissolve and prepare a fiber core spinning solution. Here, the heating temperature is 200-300°C, and solvent C is white oil. S4: Ultra-high molecular weight polyethylene A is added to solvent D and mixed uniformly. The mixture is then introduced into a twin-screw extruder and extruded to dissolve the polyethylene, thereby preparing a fiber sheath spinning solution. Here, the heating temperature is 200-300°C, and solvent D is white oil. S5: After spinning by enclosing the fiber core layer spinning solution with the fiber sheath layer spinning solution, extraction, drying, and heat stretching are performed to obtain the finished product, a sheath-core composite polyethylene fiber. Here, the spinning temperature is 220-260°C.

[0009] Compared to conventional technology, the beneficial effects of the present invention are as follows.

[0010] 1. In the present invention, by introducing mineral fibers, inorganic ultrafine powder, and graphene to induce interfacial interactions, filling with ultra-high molecular weight polyethylene, and forming a synergistic reinforcement of two components through the synergistic effect of the sheath-core composite process, the cut resistance of the sheath-core composite polyethylene fiber is greatly improved without affecting the comfort of the sheath-core composite polyethylene fiber. Based on this, in the sheath-core composite process of the present invention, the fiber core layer is manufactured using ultra-high molecular weight polyethylene to which inorganic ultrafine powder, graphene, mineral fibers, color adhesive, and antioxidant are added, and the fiber sheath layer is manufactured using ordinary ultra-high molecular weight polyethylene, thereby achieving the effect of protecting the fiber core layer. This effectively solves the problems that sheath-core composite polyethylene fibers tend to shed powder, fade in color, and wear down equipment when used in subsequent processes.

[0011] 2. The color of the sheath-core composite polyethylene fiber of the present invention is determined by the content of mineral fibers, inorganic ultrafine powder, graphene, color sizing agent, and antioxidant in the fiber core layer. By changing the content of the above components, particularly the color sizing agent, it is possible to produce high-strength sheath-core composite polyethylene fibers of various colors, further improving the cut resistance of the sheath-core composite polyethylene fiber and further improving the convenience of coloring without affecting the color fastness of the sheath-core composite polyethylene fiber. [Modes for carrying out the invention]

[0012] The present invention will be further described below with reference to examples, but these examples are not intended to limit the present invention.

[0013] The raw materials used in this invention are commercially available raw materials.

[0014] Example 1 Manufacturing of sheath-core composite polyethylene fibers S1: Ceramic powder was added to white oil, pretreated by dispersion and stirring, and then machined using a sand mill to control the particle size to 10-300 μm and the aspect ratio to a range of 1-30 to obtain the first auxiliary agent. S2: Antioxidant 1076 and magnesium oxide powder with an average radius of 0.1 μm were added to white oil. After addition, the mixture was pretreated by dispersion and stirring, and then sanded to obtain the second auxiliary agent. S3: Ultra-high molecular weight polyethylene B (ultra-high molecular weight polyethylene powder with a weight-uniform molecular weight of 1 million), the first auxiliary agent, and the second auxiliary agent were added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber core spinning solution. S4: Ultra-high molecular weight polyethylene A (ultra-high molecular weight polyethylene powder with a weight-average molecular weight of 4 million) was added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber sheath spinning solution. S5: Using a spinneret, the fiber sheath layer spinning solution was encapsulated in the fiber core layer spinning solution, spun at 220-260°C, cooled in a water bath to harden into gel fibers, and then extracted, dried, and heat-stretched to obtain white sheath-core composite polyethylene fibers. In the manufacturing process described above, the amounts used for ceramic powder, magnesium oxide, and antioxidant 1076 were 22%, 5%, and 0.5% of the total mass of ultra-high molecular weight polyethylene B, the first additive, and the second additive, respectively. A fabric was prepared using the obtained white sheath-core composite polyethylene fibers. The cut resistance grade of the obtained fabric was A3 (200D) or higher, and A4 (400D) or higher.

[0015] Example 2 Manufacturing of sheath-core composite polyethylene fibers S1: Nanocrystalline silicon carbide powder and ceramic powder were added to white oil, pre-treated with dispersion and stirring, and then machined using a sand mill to control the particle size to 10-300 μm and the aspect ratio to a range of 1-30 to obtain the first auxiliary agent. S2: Colored paste, antioxidant 300, and graphene powder (modified graphene powder may be used if necessary) were added to the white oil. After the addition was complete, the mixture was pretreated by dispersion and stirring, and then sanded to obtain the second auxiliary agent. S3: Ultra-high molecular weight polyethylene B (ultra-high molecular weight polyethylene powder with a weight-average molecular weight of 2.5 million), the first auxiliary agent, and the second auxiliary agent were added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber core spinning solution. S4: Ultra-high molecular weight polyethylene A (ultra-high molecular weight polyethylene powder with a weight-average molecular weight of 2.5 million) was added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber sheath layer spinning solution. S5: Using a spinneret, the fiber sheath layer spinning solution was encapsulated in the fiber core layer spinning solution, spun at 220-260°C, cooled in a water bath to harden into gel fibers, and then extracted, dried, and heat-stretched to obtain gray sheath-core composite polyethylene fibers. In the manufacturing process described above, the amounts used for nanocrystalline silicon carbide powder, ceramic powder, coloring agent, antioxidant 300, and graphene powder were 5%, 15%, 8%, 0.5%, and 2% of the total mass of ultra-high molecular weight polyethylene B, the first additive, and the second additive, respectively. A fabric was created using the obtained gray sheath-core composite polyethylene fibers. The resulting fabric had a cut resistance grade of A4 (200D / 400D) or higher.

[0016] Example 3 Manufacturing of sheath-core composite polyethylene fibers S1: Nanocrystalline silicon carbide powder was added to white oil, pretreated with dispersion and stirring, and then machined using a sand mill to control the particle size to 10-300 μm and the aspect ratio to a range of 1-30 to obtain the first auxiliary agent. S2: Colored paste, antioxidant 168, and graphene powder (modified graphene powder may be used if necessary) were added to the white oil, and after pretreatment of dispersion and stirring following the addition, the second auxiliary agent was obtained by sanding. S3: Ultra-high molecular weight polyethylene B (ultra-high molecular weight polyethylene powder with a weight-average molecular weight of 4 million), the first auxiliary agent, and the second auxiliary agent were added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber core spinning solution. S4: Ultra-high molecular weight polyethylene A (ultra-high molecular weight polyethylene powder with a weight-average molecular weight of 1 million) was added to white oil and mixed uniformly. The mixture was then introduced into a twin-screw extruder, heated at 200-300°C, and extruded to dissolve and obtain a fiber sheath spinning solution. S5: Using a spinneret, the fiber sheath layer spinning solution was encapsulated in the fiber core layer spinning solution, spun at 220-260°C, cooled in a water bath to harden into gel fibers, and then extracted, dried, and heat-stretched to obtain black sheath-core composite polyethylene fibers. In the manufacturing process described above, the amounts used for nanocrystalline silicon carbide powder, coloring agent, antioxidant 168, and graphene powder were 20%, 5%, 0.5%, and 5% of the total mass of ultra-high molecular weight polyethylene B, the first auxiliary agent, and the second auxiliary agent, respectively. A fabric was made using the obtained black sheath-core composite polyethylene fibers. The cut resistance grade of the obtained fabric was A4 (200D), A5 (400D) or higher.

[0017] The obtained white sheath-core composite polyethylene fibers, gray sheath-core composite polyethylene fibers, and black sheath-core composite polyethylene fibers all had a fiber density of 0.9 to 2.0 g / cm 3 .

[0018] Furthermore, as a result of detecting each of the sheath-core composite polyethylene fibers of various colors produced in Example 1, Example 2, and Example 3 according to the standards in GB / T 14344-2022 "Tensile Properties of Chemical Fiber Filaments", their breaking strength all reached 15 to 20 cN / dtex, and the breaking elongation was ≤ 3.5%.

Claims

1. Sheath-core composite polyethylene fiber, A sheath-core composite polyethylene fiber comprising a fiber core layer and a fiber sheath layer, wherein the fiber sheath layer encloses the fiber core layer, the fiber sheath layer contains ultra-high molecular weight polyethylene A, the fiber core layer contains ultra-high molecular weight polyethylene B, a first additive and a second additive, the first additive contains nanocrystalline silicon carbide powder, the second additive contains graphene, and the second additive may or may not contain a coloring agent and an antioxidant.

2. The sheath-core composite polyethylene fiber according to claim 1, characterized in that the amounts used for the first and second auxiliary agents are 0.1 to 60% and 0.1 to 30% of the total mass of ultra-high molecular weight polyethylene B, the first auxiliary agent, and the second auxiliary agent, respectively.

3. The sheath-core composite polyethylene fiber according to claim 2, characterized in that the amounts used for graphene, coloring agent, and antioxidant are 0-10%, 0-20%, and 0-2% of the total mass of ultra-high molecular weight polyethylene B, the first auxiliary agent, and the second auxiliary agent, respectively.

4. The sheath-core composite polyethylene fiber according to claim 1, characterized in that the weight-average molecular weight of the ultra-high molecular weight polyethylene A and ultra-high molecular weight polyethylene B is both 1 million to 4 million.

5. A method for producing a sheath-core composite polyethylene fiber according to any one of claims 1 to 4, comprising the following S1 to S5: S1: Nanocrystalline silicon carbide powder is added to solvent A, pre-treated by dispersion and stirring, and then sanded to produce the first auxiliary agent. S2: Add graphene to solvent B, and optionally add color sizing agent and antioxidant. After the addition is complete, pretreatment of dispersion and stirring is performed, followed by sanding to produce the second auxiliary agent. S3: After uniformly mixing ultra-high molecular weight polyethylene B, the first auxiliary agent, and the second auxiliary agent in solvent C, the mixture is introduced into a twin-screw extruder, heated, and extruded to dissolve and prepare a fiber core spinning solution. S4: Ultra-high molecular weight polyethylene A is added to solvent D and mixed uniformly, then introduced into a twin-screw extruder and extruded to dissolve and prepare a fiber sheath layer spinning solution. S5: A manufacturing method characterized by obtaining a sheath-core composite polyethylene fiber, which is a finished product, by enclosing the fiber core layer spinning solution with the fiber sheath layer spinning solution and spinning it, followed by extraction, drying, and heat stretching.

6. The manufacturing method according to claim 5, characterized in that, in step S1, when sanding, the particle size is controlled to be between 10 and 300 μm and the aspect ratio is controlled to be in the range of 1 to 30.

7. In step S3, the heating temperature is 200 to 300°C. In step S4, the heating temperature is 200 to 300°C. The manufacturing method according to claim 5, characterized in that in step S5, the spinning temperature is 220 to 260°C.

8. The manufacturing method according to claim 5, characterized in that solvent A, solvent B, solvent C, and solvent D are all white oils.