A process for the preparation of a modified ultra-high molecular weight polyethylene fiber by means of twin-screw melt spinning

Abstract

The application discloses a kind of modified ultra-high molecular weight polyethylene fiber's bicomponent melt spinning preparation process, including modified ultra-high molecular weight polyethylene powder and obtains powder A, processing toner and obtains auxiliary B, mixed raw material is prepared core layer raw material C, core layer raw material C and powder A are sheared melt through bicomponent spinning assembly, finally air-cooling setting and hot roller traction, obtain modified high molecular weight polyethylene fiber finished product.The application realizes fiber skin layer covering fiber core layer by bicomponent spinning, with the safe harmless polyethylene melt skin layer, polyethylene melt added with functional material in core layer is wrapped, effectively overcome the finished product fiber powder after adding functional material in single component spinning process, possible damage equipment, adverse reaction caused after contacting with human body etc., eliminate many solution spinning limitations, widen the application range and scene of melt spinning.

Description

Technical Field

[0001] This invention relates to the field of new material preparation technology, and more specifically, to a bicomponent melt spinning preparation process for modified ultra-high molecular weight polyethylene fibers. Background Technology

[0002] Melt spinning accounts for a relatively small proportion of the production of high-performance fibers, mainly used in the preparation of pitch-based carbon fiber precursors. Ultra-high molecular weight polyethylene (UHMWPE) fiber, one of the three major high-performance fibers, is primarily produced through solution spinning. Solution spinning has shortcomings in terms of cost, pollution, and recycling. However, with the continuous development of UHMWPE fiber applications in recent years, these intractable problems of solution spinning have not been resolved, leading to a shift in the production process of UHMWPE fiber from solution spinning to melt spinning.

[0003] Due to its late start, the process route for melt spinning of high molecular weight polyethylene fibers in China is not mature at present, and most of them are based on single components, using single-component screws as the main spinning equipment, or developing multiple feeding ports on the screw to match the production process requirements, which has great limitations. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a two-component melt spinning preparation process for modified ultra-high molecular weight polyethylene fiber, thereby solving one or more of the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A two-component melt spinning process for preparing modified ultra-high molecular weight polyethylene fiber, S1, modifying ultra-high molecular weight polyethylene powder to obtain powder A; S2. Select and process suitable color powder to obtain auxiliary agent B; S3. Mix powder A and additive B thoroughly according to the ratio to obtain core layer raw material C; Powder A is used as the raw material for the fiber skin layer; S4. The core material C and powder A are conveyed to different feed channels and sheared and melted to obtain fiber core melt flow and fiber sheath melt flow respectively. S5. Use a two-component spinning assembly to wrap the fiber core melt flow with the fiber sheath melt flow for spinning. S6. The nascent gel filaments are air-cooled and shaped, and then hot-rolled to directly obtain the modified high molecular weight polyethylene fiber product.

[0006] Furthermore, in step S1, the ultra-high molecular weight polyethylene fiber is modified by one or more methods such as physical coating, chemical coating, and high-energy surface modification.

[0007] Furthermore, in step S1, the modification of ultra-high molecular weight polyethylene fibers is achieved through infrared irradiation, plasma irradiation, electron beam radiation, polymer action, coupling agents such as silanes, or surfactants.

[0008] Furthermore, in step S1, the molecular weight of the unmodified ultra-high molecular weight polyethylene powder is between 100,000 and 1,500,000, and the density of the modified ultra-high molecular weight polyethylene powder is 0.2 g / cm³. 3 ~1.0g / cm 3 .

[0009] Furthermore, in step S2, the particle size of additive B is less than 10 μm, and additive B is easy to disperse and not easy to aggregate.

[0010] Furthermore, in step S3, the amount of additive B added is 0-6% of the total mass of the core layer raw material C.

[0011] Furthermore, in step S4, the shear melting temperature of the core layer raw material C and powder A is 160~320℃.

[0012] Furthermore, in step S6, the spinning temperature is 220~280℃, and the color and chromaticity of the finished ultra-high molecular weight polyethylene fiber are directly determined by additive B.

[0013] Furthermore, the bicomponent spinning assembly includes two feed channels and a bicomponent mechanism, where the core material C and powder A are transported and filtered through different feed channels before entering the bicomponent mechanism for melt spinning.

[0014] Furthermore, each of the material channels includes a material transfer section with a screw, a filter, and a metering pump connected in sequence, and the material channels converge into the two-component mechanism.

[0015] In summary, the present invention has the following beneficial effects: by achieving fiber sheath coating of fiber core layer through bicomponent spinning, and by using a safe and harmless polyethylene melt sheath to wrap the polyethylene melt with added functional materials in the core layer, the present invention effectively overcomes the problems of fiber powder shedding after adding functional materials in single-component spinning process, which may damage equipment and cause adverse reactions after contact with human body. It also eliminates many limitations of solution spinning and broadens the application range and scenarios of melt spinning. Attached Figure Description

[0016] Figure 1 A process flow diagram for one embodiment of the present invention; Figure 2 A structural diagram of a bicomponent spinning assembly according to one embodiment of the present invention.

[0017] In the diagram: 1. Two-component mechanism; 2. First metering pump; 3. Second metering pump; 4. First filter; 5. Second filter; 6. First screw; 7. Second screw. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1-2 The present invention will be described in further detail below. Example

[0019] A bicomponent melt spinning process for preparing modified ultra-high molecular weight polyethylene fibers, such as... Figure 1 As shown, it consists of six steps: S1. Modification of ultra-high molecular weight polyethylene (UHMWPE) fibers is achieved through one or more methods, including physical coating, chemical coating, and high-energy surface modification. These methods include infrared irradiation, plasma irradiation, electron beam radiation, polymer action, coupling agents such as silanes, or surfactants. No special modifications are made to the modification methods; the selected modifiers are all commonly used, and the entire process is implemented using methods common in the field. For example, UHMWPE powder is mixed with other polymers or resins at high temperatures, and then the other polymers are melted and uniformly coated onto the surface of the UHMWPE powder to complete the modification. Another example is the use of nitriding plasma to nitrid the surface of UHMWPE powder, increasing the surface hardness and wear resistance of the material. The UHMWPE powder before modification must meet the requirements of GB / T 32679-2016, with a molecular weight between 100,000 and 1,500,000, and the density of the modified UHMWPE powder must be 0.2 g / cm³. 3 ~1.0g / cm 3 Here, the powder density refers to the corresponding melt density. The final product is powder A.

[0020] S2. Select a suitable colorant. The particle size of the colorant should be controlled below 10μm, and it should be easily dispersed and not easily aggregated. It is important to note that the colorant directly affects the chroma and color properties of the final modified ultra-high molecular weight polyethylene fiber product. That is, the color and depth of the final modified ultra-high molecular weight polyethylene fiber product are directly determined by the added colorant. The selection of colorant needs to be adjusted according to production requirements. Finally, additive B is obtained.

[0021] S3. Mix the powder A obtained in step S1 and the auxiliary agent B obtained in step S2 thoroughly in a specific ratio. Generally, the amount of auxiliary agent B added is 6% of the total mass of the mixture. Finally, the core layer raw material C is obtained, and the additional powder A is used as the fiber skin layer raw material.

[0022] S4~S5, This process depends on, as follows Figure 2The bicomponent spinning assembly shown comprises two feed channels and a bicomponent mechanism 1. The two feed channels are arranged in parallel and eventually converge into the bicomponent mechanism 1. One feed channel includes a feeding mechanism with a first screw 6, a first filter 4, and a first metering pump 2 connected in sequence. The other feed channel includes a feeding mechanism with a second screw 7, a second filter 5, and a second metering pump 3 connected in sequence. Both feed channels eventually converge into the bicomponent mechanism 1.

[0023] S4. The core material C and powder A obtained in step S3 are introduced into different feed channels. After processes such as spiral feeding, impurity removal and filtration, and quantitative limiting, they finally enter the two-component mechanism 1. With the core material C as the center, powder A is wrapped around it. After the core material C and powder A enter the feed channel, they are sheared and melted at 320°C to obtain the core melt flow and the sheath melt flow of the fiber, respectively. S5. The core melt flow and skin melt flow obtained in step S4 are wrapped by the skin melt flow to encapsulate the core melt flow using a two-component component, and then melt spinning is performed. S6. The nascent gel filaments obtained in step S5 are air-cooled and then hot-rolled at 280°C to directly stretch into the required fineness of modified high molecular weight polyethylene fiber in one step.

[0024] Example 2 differs from Example 1 in that the amount of color powder added accounts for 3% of the total mass of the mixture. After the core layer raw material C and powder A enter the feed channel, they are sheared and melted at 240°C. The nascent gel fiber obtained in step S5 is air-cooled and shaped, and then hot roller stretching is performed at 250°C.

[0025] Example 3 differs from Example 1 in that no color powder is added. After the core layer raw material C and powder A enter the feed channel, they are sheared and melted at 160°C. The nascent gel fiber obtained in step S5 is air-cooled and shaped, and then hot roller stretching is performed at 220°C.

[0026] Example 4 differs from Example 1 in that the amount of color powder added accounts for 4% of the total mass of the mixture. After the core layer raw material C and powder A enter the feed channel, they are sheared and melted at 260°C. The nascent gel fiber obtained in step S5 is air-cooled and shaped, and then hot roller stretching is performed at 260°C.

[0027] Example 5 differs from Example 1 in that the amount of color powder added accounts for 2% of the total mass of the mixture. After the core layer raw material C and powder A enter the feed channel, they are sheared and melted at 210°C. The nascent gel fiber obtained in step S5 is air-cooled and shaped, and then hot roller stretching is performed at 240°C.

[0028] Samples from Examples 1-5 were collected and observed, and relevant tests were performed. The results are as follows: All sample fibers formed a complete and harmless fiber sheath (composed of harmless polyethylene) outside the fiber core layer, forming a sheath-encased core structure. A functional material (pigment powder) melt was added inside the core layer, and no powder shedding or other structural defects occurred subsequently. Therefore, it can be concluded that the damage to equipment during subsequent processing is negligible, and the fiber core layer will not directly contact the human body, thus avoiding adverse reactions. The fiber sample performance parameters are as follows: The fracture strength is above 15 cN / dtex; The elongation at break is not higher than 3%; The fiber linear density deviation rate is less than 4%, which meets the requirements of GB / T 14343 standard. The color fastness test of the fiber dyeing is not lower than grade 4, which meets the standard requirements of GB 18401-2010.

[0029] It should be noted that this specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A bicomponent melt spinning process for preparing modified ultra-high molecular weight polyethylene fibers, characterized in that: S1. Modify ultra-high molecular weight polyethylene powder to obtain powder A; S2. Select and process suitable color powder to obtain auxiliary agent B; S3. Mix powder A and additive B thoroughly according to the ratio to obtain core layer raw material C; Powder A is used as the raw material for the fiber skin layer; S4. The core material C and powder A are conveyed to different feed channels and sheared and melted to obtain fiber core melt flow and fiber sheath melt flow respectively. S5. Use a two-component spinning assembly to wrap the fiber core melt flow with the fiber sheath melt flow for spinning. S6. The nascent gel filaments are air-cooled and shaped, and then hot-rolled to directly obtain the modified high molecular weight polyethylene fiber product.

2. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S1, ultra-high molecular weight polyethylene fibers are modified by one or more methods such as physical coating, chemical coating, and high-energy surface modification.

3. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 2, characterized in that: In step S1, the modification of ultra-high molecular weight polyethylene fibers is achieved through infrared irradiation, plasma irradiation, electron beam radiation, polymer action, coupling agents such as silanes, or surfactants.

4. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S1, the molecular weight of the unmodified ultra-high molecular weight polyethylene powder is between 100,000 and 1,500,000, and the density of the modified ultra-high molecular weight polyethylene powder is 0.2 g / cm³. 3 ~1.0g / cm 3 .

5. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S2, the particle size of additive B is less than 10 μm, and additive B is easy to disperse and not easy to aggregate.

6. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S3, the amount of additive B added is 0-6% of the total mass of the core layer raw material C.

7. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S4, the shear melting temperature of the core layer raw material C and powder A is 160~320℃.

8. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: In step S6, the spinning temperature is 220~280℃, and the color and chroma of the finished ultra-high molecular weight polyethylene fiber are directly determined by additive B.

9. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: The bicomponent spinning assembly includes two feed channels and a bicomponent mechanism. The core material C and powder A are transported and filtered through different feed channels before entering the bicomponent mechanism for melt spinning.

10. The bicomponent melt spinning preparation process of modified ultra-high molecular weight polyethylene fiber according to claim 9, characterized in that: Each of the aforementioned feed channels includes a feed transfer section with a screw, a filter, and a metering pump connected in sequence, and the feed channels converge into the two-component mechanism.

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