A method for preparing an ultra-high molecular weight polyethylene / continuous fiber composite plate

Abstract

The application belongs to the field of polymer composite materials, and particularly relates to a preparation method of an ultrahigh molecular weight polyethylene / continuous fiber composite plate. The method comprises the following steps: (1) mixing ultrahigh molecular weight polyethylene, high-carbon straight-chain hydrocarbon and an antioxidant, and then mixing and extruding to obtain a viscous flow extrudate; the high-carbon straight-chain hydrocarbon is a normal alkane with 10-16 carbon atoms; (2) compounding the viscous flow extrudate with a continuous fiber fabric, and then performing hot extrusion to obtain a hot extruded product; and (3) sequentially performing hot soaking, cooling, cold extrusion and extraction treatment on the hot extruded product to obtain a composite plate. In the application, the high-carbon straight-chain hydrocarbon is used to dissolve the ultrahigh molecular weight polyethylene at high temperature, and then the high-carbon straight-chain hydrocarbon is removed through cold extrusion and extraction, so that the ultrahigh molecular weight polyethylene is hot extrusion compounded with the continuous fiber fabric to realize molding. In the whole molding process, no special and complicated equipment is needed, and the method is suitable for industrialized continuous production. Moreover, the obtained composite plate exhibits excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials, and specifically relates to a method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) possesses excellent wear resistance, corrosion resistance, impact resistance, and low-temperature resistance, making it an engineering plastic with superior comprehensive physical and mechanical properties. However, its rigidity is relatively low, especially due to its high molecular weight and high degree of entanglement between molecular chains, making it unsuitable for processing using ordinary extrusion or injection molding methods, thus limiting its application range. Currently, the production of UHMWPE products still mainly relies on compression-sintering methods, resulting in relatively low production efficiency.

[0003] There are generally two approaches to solving the processing challenges of ultra-high molecular weight polyethylene (UHMWPE): one is to use specially designed machinery and equipment; the other is to add some modifying agents to improve the processing flowability of UHMWPE, thereby enabling it to be extruded or injection molded under relatively mild conditions. For example, Chinese invention patent application CN106317547A discloses an UHMWPE composition for extrusion molding, comprising 40-85 parts of UHMWPE, 15-60 parts of high molecular weight polyethylene, 5-10 parts of long-chain branched polyethylene, 0.4-4.0 parts of processing aids, 1.0-3.0 parts of flow modifiers, and 1-10 parts of abrasion-resistant additives. This mainly addresses the problem of UHMWPE's poor flowability, making it difficult to process using ordinary compression molding, molding, and injection molding methods.

[0004] Of the two approaches mentioned above, the first requires specially designed machinery and equipment, which is expensive; the second approach, while lower in cost and relatively easier to implement, results in a significant reduction in mechanical properties. However, achieving the composite of ultra-high molecular weight polyethylene and continuous fibers is even more difficult, and currently, there is no such equipment or technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels, which solves the problem of low rigidity of existing ultra-high molecular weight polyethylene materials, thereby expanding their application range.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] A method for preparing an ultra-high molecular weight polyethylene / continuous fiber composite board includes the following steps:

[0008] (1) Ultra-high molecular weight polyethylene, high carbon straight-chain hydrocarbons and antioxidants are mixed, compounded and extruded to obtain a viscous extrudate; the high carbon straight-chain hydrocarbons are n-alkanes with 10 to 16 carbon atoms;

[0009] (2) The viscous extrudate is combined with a continuous fiber fabric and then hot-extruded to obtain a hot extrudate;

[0010] (3) The hot extruded material is subjected to hot impregnation, cooling and cold extrusion and extraction treatment in sequence to obtain composite board.

[0011] The present invention discloses a method for preparing ultra-high molecular weight polyethylene (UHMWPE) / continuous fiber composite panels. This method utilizes high-carbon linear hydrocarbons to dissolve UHMWPE at high temperatures, followed by cold extrusion and extraction to remove the high-carbon linear hydrocarbons, thereby achieving hot extrusion composite molding of UHMWPE and continuous fiber fabric. The entire molding process requires no complex or specialized equipment, making it suitable for continuous industrial production. Furthermore, the resulting composite panels exhibit excellent mechanical properties.

[0012] Preferably, in step (1), the mixture of ultra-high molecular weight polyethylene, high-carbon straight-chain hydrocarbons, and antioxidants contains 20-35% by mass of ultra-high molecular weight polyethylene. The antioxidants in the mixture contain 1-3% by mass. The antioxidants are commercially available conventional varieties, such as antioxidant 1010 or antioxidant 264.

[0013] Preferably, in step (1), the extrusion temperature of the compounding extrusion is 150-170°C. More preferably, the compounding extrusion adopts a three-stage compounding extruder, with the three stages having progressively higher temperatures of 100-120°C, 120-135°C, and 150-170°C, respectively.

[0014] In step (2), the continuous fiber fabric is composited with the first and second viscous extrudates located on both sides of the continuous fiber fabric; the hot extrusion temperature is 130–150°C, and the hot extrusion pressure is 0.5–1.0 MPa. The continuous fiber fabric is a fiber cloth woven from continuous fibers. The continuous fibers are selected from glass fiber, carbon fiber, basalt fiber, etc. The surface of the continuous fibers is treated with a coupling agent to improve the composite with the resin. The coupling agent can be a conventional variety such as KH570. This type of continuous fiber fabric used for resin composite is a commercially available product and can be mass-produced by a manufacturer.

[0015] Preferably, in step (3), the hot immersion is carried out at 130-140°C for 10-20 minutes.

[0016] Preferably, in step (3), the temperature of the cold extrusion is 90 to 110°C and the pressure of the cold extrusion is 0.5 to 1.0 MPa.

[0017] The solvent used in the extraction process is a non-toxic organic solvent with a high boiling point. Preferably, in step (3), the solvent for extraction is selected from one or more combinations of dioxane, diethylene glycol dimethyl ether, and tetrachloroethylene; the extraction temperature is 50-100℃.

[0018] More preferably, in step (2), after hot extrusion, the material is co-composite with another viscous extrudate and another continuous fiber fabric, and then subjected to a second hot extrusion to obtain the hot extruded material. This step can form a two-layer fabric composite resin structure.

[0019] More preferably, the temperature of the secondary hot extrusion is 130-150°C and the pressure is 0.8-1.5 MPa. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the apparatus for producing single-layer fiber ultra-high molecular weight polyethylene / continuous fiber composite boards according to the present invention.

[0021] Figure 2 This is a schematic diagram of the two-layer fiber composite operation of the apparatus for producing ultra-high molecular weight polyethylene / continuous fiber composite boards according to the present invention.

[0022] Among them, 10-first mixing extruder, 11-second mixing extruder, 2-first extrusion double roller, 3-hot impregnation device, 4-cold extrusion device, 5-extraction device, 6-continuous fiber fabric, 7-guide roller, 8-third mixing extruder, and 9-second extrusion double roller. Detailed Implementation

[0023] The apparatus for producing ultra-high molecular weight polyethylene / continuous fiber composite sheets according to the present invention is as follows: Figure 1 and Figure 2 As shown, it includes a first mixing extruder 10, a second mixing extruder 11, a first fabric laying machine, a first extrusion double roller 2, a hot impregnation device 3, a cold extrusion device 4, and an extraction device 5.

[0024] The first extrusion twin roller 2 is located downstream of the extrusion ports of the first compounding extruder 10 and the second compounding extruder 11, allowing the extrudates from the first and second compounding extruders to be compounded with the continuous fiber fabric 6 discharged from the first fabric distribution machine before entering the gap between the twin rollers. The first compounding extruder 10 and the second compounding extruder 11 are located on opposite sides of the continuous fiber fabric's travel direction. The first extrusion twin roller 2 is connected to the hot impregnation device 3 via guide roller 7.

[0025] The hot soaking device 3 includes a hot soaking box, with a material inlet and a material outlet on the front and rear sides of the hot soaking box, respectively, and a pair of guide rollers arranged vertically inside the hot soaking box.

[0026] The cold extrusion device 4 includes a cold extrusion chamber, with a material inlet and a material outlet on the front and rear sides of the cold extrusion chamber, respectively, and a pair of extrusion rollers arranged vertically inside the cold extrusion chamber.

[0027] The extraction device 5 includes an extraction chamber with a material inlet and an outlet on its front and rear sides, respectively. The extraction chamber holds the extraction solvent and also contains a pair of vertically positioned guide rollers. During extraction, the composite plate is immersed in the extractant solution. The material inlet and outlet ends of the extraction chamber should be sealed to prevent extractant evaporation.

[0028] Figure 2 In this process, a third compounding extruder 8, a second fabric distribution machine, and a second compounding double roller 9 are also provided between the first compounding extruder 1 and the first compounding double roller 2 and the hot soaking device 3. The relative positional relationship between the third compounding extruder 8 and the second compounding double roller 9 is the same as that between the first compounding extruder 1 and the first compounding double roller 2. The extrudate from the extrusion port of the third compounding extruder 8 is compounded with the continuous fiber fabric 6 released by the second fabric distribution machine and then enters the double roller gap of the second compounding double roller 9.

[0029] The working process of the above device is as follows:

[0030] Ultra-high molecular weight polyethylene (UHMWPE) and high-carbon linear hydrocarbons are mixed in a high-speed mixer and then fed into a twin-screw extruder. Continuous fiber fabric is introduced at the same time. The extrudate and continuous fiber fabric are fed into an extrusion-twin-roll system for extrusion. The extrudate is then conveyed to a hot box for impregnation. After impregnation, the sheet is air-cooled and then extruded again to precipitate some of the high-carbon linear hydrocarbons. The high-carbon linear hydrocarbons are then extracted with an extractant, which is the UHMWPE / continuous fiber composite material (single-layer fiber fabric).

[0031] If multi-layer composite is to be performed, according to Figure 2 As shown, a second extrusion-double roller system is set up to form a composite board with three layers of resin and two layers of fabric, which then enters the hot impregnation-cold extrusion-extraction process in sequence.

[0032] Based on the above apparatus, the preparation of ultra-high molecular weight polyethylene / continuous fiber composite boards is achieved according to the following method:

[0033] (1) Mix ultra-high molecular weight polyethylene and high carbon straight-chain hydrocarbons and then extrude them to obtain a viscous extrudate.

[0034] (2) The viscous extrudate is combined with a continuous fiber fabric and then hot-extruded to obtain a hot extrudate;

[0035] (3) The hot extruded material is subjected to hot impregnation, cooling and cold extrusion and extraction treatment in sequence to obtain composite board.

[0036] Step (1) involves dissolving high-carbon straight-chain hydrocarbons in ultra-high molecular weight polyethylene to facilitate the subsequent melting and extrusion process. The high-carbon straight-chain hydrocarbons can be selected from n-alkanes with 10 to 16 carbon atoms.

[0037] Step (2) is a co-extrusion compounding process for combining the viscous extrudate with the continuous fiber fabric. In this step, the viscous extrudate and the continuous fiber fabric are initially compounded, and the viscous extrudate can be wetted from one side to the other through the fabric pores. The continuous fiber fabric can be made of glass fiber fabric, carbon fiber fabric, mineral fiber fabric, plant fiber fabric, etc. The co-extrusion compounding temperature is maintained at 130-150℃, at which time the resin material is still in a viscous flow state.

[0038] Step (3) includes hot soaking, cooling followed by cold extrusion and extraction.

[0039] The purpose of hot impregnation is to promote the full bonding between the resin material and the fabric fibers. The hot impregnation temperature is 130–140℃, and the hot impregnation time is 10–20 minutes.

[0040] Cold extrusion after cooling utilizes the decreased solubility of high-carbon straight-chain hydrocarbons in ultra-high molecular weight polyethylene after cooling, extruding the precipitated high-carbon straight-chain hydrocarbons. In this step, the cold extrusion temperature is 90–110℃, and the extrusion pressure is 0.5–1 MPa.

[0041] Extraction involves using an extraction solvent to remove residual solvent from the sheet material after cold extrusion. The extraction solvents used in this process include dioxane (bp 101℃), diethylene glycol dimethyl ether (bp 162℃), and tetrachloroethylene (bp 121℃). The extraction temperature is 50–100℃.

[0042] For cases requiring a second extrusion-twin-roll system, the extrusion pressure of the second extrusion twin rolls is 0.8–1.5 MPa, and the extrusion temperature is 130–150 °C.

[0043] The implementation process of the present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available conventional varieties. The number average molecular weight of ultra-high molecular weight polyethylene is 3-4 million.

[0044] I. Specific embodiments of the preparation method of the ultra-high molecular weight polyethylene / continuous fiber composite board of the present invention are as follows:

[0045] Examples 1-3 are single-layer fiber fabric composite boards, wherein the fiber fabrics are woven in the same way, the resin / fiber ratio (mass ratio) is set to 1:3, and the composite thickness is 4mm.

[0046] Example 1

[0047] The preparation method of ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment is based on Figure 1 The apparatus shown includes the following steps:

[0048] (1) Ultra-high molecular weight polyethylene (UHMWPE) is mixed evenly with high-carbon straight-chain hydrocarbons and 1% of 1010 antioxidant in a high-speed mixer, wherein the content of UHMWPE is 20%, to obtain a mixture. The high-carbon straight-chain hydrocarbon is n-dodecane.

[0049] (2) The mixture is fed into a three-stage twin-screw mixer for mixing and extrusion. The temperatures of the three stages of the three-stage twin-screw mixer are set to 100℃, 120℃ and 150℃ respectively.

[0050] (3) The extruded material from the compounding process is fed into a two-roll extruder at a temperature of 130°C through a die (with the same size as the continuous fiber fabric). At the same time, a continuous glass fiber fabric is introduced. The resin material and the continuous fiber fabric are co-extruded at a pressure of 0.5 MPa to obtain the extruded material.

[0051] (4) The extruded material is sent into a hot box for hot impregnation. The hot impregnation temperature is 130℃ and the holding time is 10min. Then it is air-cooled to 90℃ and then cold-extruded. The cold extrusion pressure is 0.8MPa. After that, it is extracted from n-dodecane in a 50℃ dioxane extraction tank. Then it is washed with a water washing tank containing surfactant to remove the surface oil. After drying, ultra-high molecular weight / continuous fiber composite board (single-layer fiber fabric composite) is obtained.

[0052] Example 2

[0053] The preparation method of the ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment differs from that in Example 1 in that, in step (1), the content of ultra-high molecular weight polyethylene is 25%, and the high carbon straight-chain hydrocarbon is n-tetradecane.

[0054] In step (2), the temperatures of the three stages of compounding extrusion are 110℃, 130℃ and 160℃ respectively.

[0055] In step (3), the continuous fiber fabric is carbon fiber. The co-extrusion temperature is 140℃ and the pressure is 0.6MPa.

[0056] In step (4), the hot immersion is carried out at 140°C for 15 minutes. The cold extrusion temperature is 100°C and the cold extrusion pressure is 0.8 MPa. The extraction temperature is 90°C and the extraction solvent used is diethylene glycol dimethyl ether.

[0057] Example 3

[0058] The preparation method of the ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment differs from that in Example 1 in that, in step (1), the content of ultra-high molecular weight polyethylene is 30% and the solvent is n-hexadecane.

[0059] In step (2), the three temperatures of the compounding extrusion are 120℃, 135℃ and 170℃ respectively.

[0060] In step (3), the continuous fiber fabric is basalt fiber. The co-extrusion temperature is 150℃ and the pressure is 1MPa.

[0061] In step (4), the hot immersion temperature is 140℃ for 20 minutes. The cold extrusion temperature is 110℃ and the cold extrusion pressure is 1MPa. The extraction temperature is 100℃ and the extraction solvent used is tetrachloroethylene.

[0062] Examples 4-6 are two-layer fiber fabric composite boards with the same fiber fabric weaving method, a resin / fiber ratio (mass ratio) of 1:3, and a composite thickness of 8mm.

[0063] Example 4

[0064] The preparation method of ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment is based on Figure 2 The device shown, in Figure 1 The device is modified by adding an extruder and a fabric laying machine. The differences in the specific preparation process compared to Example 1 are explained below:

[0065] In step (3), the co-extruded material, the extrudate from another twin-screw mixer, and another continuous glass fiber fabric are fed into a twin-roll extruder at a temperature of 150°C for compound co-extrusion. The pressure of the compound co-extrusion is 0.8 MPa. The remaining steps are the same as in Example 1.

[0066] Example 5

[0067] The preparation method of ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment is based on Figure 2 The device shown, in Figure 1 The device is modified by adding an extruder and a fabric laying machine. The differences in the specific preparation process compared to Example 2 are explained below:

[0068] In step (3), the co-extruded material, the extrudate from another twin-screw mixer, and another carbon fiber fabric are fed into a twin-roll extruder at a temperature of 150°C for compound co-extrusion. The pressure of the compound co-extrusion is 0.8 MPa. The remaining steps are the same as in Example 2.

[0069] Example 6

[0070] The preparation method of ultra-high molecular weight polyethylene / continuous fiber composite board in this embodiment is based on Figure 2 The device shown, in Figure 1 The device is modified by adding an extruder and a fabric laying machine. The differences in the specific preparation process compared to Example 3 are explained below:

[0071] In step (3), the co-extruded material, the extrudate from another twin-screw mixer, and another basalt fiber fabric are fed into a twin-roll extruder at a temperature of 150°C for compound co-extrusion. The pressure of the compound co-extrusion is 0.8 MPa. The remaining steps are the same as in Example 3.

[0072] II. Experimental Examples

[0073] This experiment tested the mechanical properties of the composite boards obtained in Examples 1 to 6. The tensile strength and modulus were tested according to GB / T1040.2-2006, and the flexural modulus was tested according to GB / T9341-2008. The test results are shown in Table 1 below.

[0074] Table 1. Mechanical property test results of composite panels in Examples 1-6

[0075] Instance number Tensile strength / MPa Tensile modulus / MPa Flexural modulus / MPa Example 1 41 1450 1550 Example 2 46 1740 1880 Example 3 46 1670 1840 Example 4 52 2340 2560 Example 5 55 2650 2880 Example 6 54 2250 2360

[0076] As can be seen from the experimental results in Table 1, the composite board obtained in the example has good mechanical properties, and the production process is simple and controllable, requiring no special equipment, making it suitable for large-scale industrial production of this type of composite board.

Claims

1. A method for preparing an ultra-high molecular weight polyethylene / continuous fiber composite board, characterized in that, Includes the following steps: (1) Ultra-high molecular weight polyethylene, high carbon straight-chain hydrocarbons and antioxidants are mixed and extruded to obtain a viscous extrudate; the high carbon straight-chain hydrocarbons are n-alkanes with 10 to 16 carbon atoms; (2) The viscous extrudate is combined with a continuous fiber fabric and then hot-extruded to obtain a hot-extruded product; Continuous fiber fabric is a fiber cloth woven from continuous fibers, which are selected from glass fiber, carbon fiber or basalt fiber; (3) The hot extruded material is subjected to hot impregnation, cooling and cold extrusion and extraction treatment in sequence to obtain composite board; the hot impregnation temperature is 130~140℃; the cooling and cold extrusion is to use the decrease in solubility of high carbon straight-chain hydrocarbons in ultra-high molecular weight polyethylene after cooling to extrude the precipitated high carbon straight-chain hydrocarbons; the cold extrusion temperature is 90~110℃; the extraction temperature is 50~100℃.

2. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite board as described in claim 1, characterized in that, In step (1), the mixture of ultra-high molecular weight polyethylene, high carbon straight-chain hydrocarbons and antioxidants contains 20-35% ultra-high molecular weight polyethylene by mass.

3. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels as described in claim 1, characterized in that, In step (1), the extrusion temperature of the compounding extrusion is 150~170℃.

4. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite board as described in claim 3, characterized in that, The compounding extrusion adopts a three-stage compounding extruder, with the temperature of the three stages increasing sequentially to 100~120℃, 120~135℃, and 150~170℃ respectively.

5. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite board as described in claim 1, characterized in that, In step (2), the continuous fiber fabric is compounded with the first and second viscous extrudates located on both sides of the continuous fiber fabric; the hot extrusion temperature is 130~150℃ and the hot extrusion pressure is 0.5~1.0MPa.

6. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite board as described in claim 1, characterized in that, In step (3), the hot immersion is carried out at 130~140℃ for 10~20 minutes.

7. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels as described in claim 6, characterized in that, In step (3), the pressure of the cold extrusion is 0.5~1.0MPa.

8. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels as described in claim 1, 6, or 7, characterized in that, In step (3), the solvent for extraction is selected from one or more combinations of dioxane, diethylene glycol dimethyl ether, and tetrachloroethylene.

9. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite panels according to any one of claims 1 to 7, characterized in that, In step (2), after hot extrusion, the material is co-composite with another viscous extrudate and another continuous fiber fabric, and then subjected to a second hot extrusion to obtain the hot extruded material.

10. The method for preparing ultra-high molecular weight polyethylene / continuous fiber composite board as described in claim 9, characterized in that, The temperature of the secondary hot extrusion is 130~150℃, and the pressure is 0.8~1.5MPa.

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