An ultra-high molecular weight polyethylene wet composite film and a preparation process thereof

Abstract

The application belongs to the field of novel functional materials, and particularly relates to a preparation process of an ultrahigh molecular weight polyethylene wet composite film. The process adopts a two-step method to prepare the ultrahigh molecular weight polyethylene composite film, which is wet granulation and dry melt extrusion. The process solves the problem of obvious molecular weight attenuation of the ultrahigh molecular weight polyethylene in the melt extrusion granulation process under the premise of ensuring the stability of the molecular weight of the product, obviously improves the processing performance of the product, and reduces the processing difficulty of the product.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of new functional materials, and particularly relates to a kind of super high molecular weight polyethylene wet composite film and its preparation process. BACKGROUND

[0002] Super high molecular weight polyethylene (UHMWPE for short) is a kind of linear polyethylene with ultra-long linear molecular chain structure, and the viscosity average molecular weight is more than 1.5 million. UHMWPE has the same molecular structure as ordinary PE, but the extremely high molecular weight gives UHMWPE many excellent properties that ordinary PE cannot match. The outstanding two properties of UHMWPE are excellent friction and wear performance and excellent impact resistance. UHMWPE has self-lubricating property, and its friction coefficient is small. In the self-lubricating state, the friction coefficient is 0.10-0.20, and in the water / oil lubricating state, the friction coefficient is 0.05-0.10. The low friction coefficient value can be comparable to polytetrafluoroethylene. UHMWPE has excellent wear resistance. Compared with other materials, the wear resistance of UHMWPE ranks first among plastics, and is even several to dozens of times more wear-resistant than carbon steel and brass. UHMWPE has extremely high impact strength, which is much higher than that of polycarbonate with excellent toughness, and ranks first among engineering plastics. Moreover, UHMWPE can maintain good toughness in liquid nitrogen environment (-196℃). In addition, UHMWPE also has the advantages of low water absorption, chemical resistance, hygiene, non-toxicity, anti-adhesion, stress cracking resistance, and shock absorption and noise reduction.

[0003] Compared with the traditional turning method, the UHMWPE film produced by the melt extrusion method can be formed in one step, and the equipment and process are simpler and more convenient, which is more conducive to industrial production. However, due to the extremely high molecular weight of UHMWPE, UHMWPE is in a high-elastic state when melted, and the viscosity of the melted state is as high as 108Pa·s, almost no flowability, and the critical shear rate is extremely low. When processed by conventional melting method, the melt is easily broken, and the molecular weight is significantly attenuated under the action of strong shear of the screw, which affects the performance of the product.

[0004] Therefore, how to solve the above problems and more efficiently obtain the production of UHMWPE film has become one of the problems to be solved in the field. SUMMARY

[0005] The present application provides a kind of super high molecular weight polyethylene wet composite film and its preparation process, which solves the problem of significant molecular weight attenuation of super high molecular weight polyethylene in the process of melt extrusion granulation, significantly improves the processing performance of the product, and reduces the processing difficulty of the product under the premise of ensuring the stability of the molecular weight of the product.

[0006] The inventive concept of the present application is as follows: thermally induced phase separation is a way to prepare microporous membranes by liquid-liquid phase separation and solid-liquid phase separation when the temperature changes. By melt blending, the polymer is mixed with a high-boiling, low-molecular-weight diluent or lubricant to form a homogeneous high-molecular-weight solution, and then the solution is phase separated by cooling. Compared with other preparation methods, this process has fewer controllable parameters, the structure is easy to control, and the melt extrusion is less difficult, the melt is less broken, the molecular weight does not decay or decays less, and the inventors provide a corresponding wet composite membrane preparation process for ultra-high molecular weight polyethylene, which ensures that the molecular weight does not decay or decays less while maintaining the excellent performance of the product.

[0007] The specific technical solutions of the present application are as follows:

[0008] An ultra-high molecular weight polyethylene wet composite membrane, comprising a support layer and an elastic layer, the support layer being ultra-high molecular weight polyethylene, and the elastic layer being one or more of a thermoplastic elastomer layer, a rubber layer, and a foamed layer;

[0009] The thickness ratio of the support layer to the elastic layer is 1:1-2:1;

[0010] Preferably, the elastic layer is composed of at least one thermoplastic elastomer layer, at least one rubber layer, or at least one foamed material layer;

[0011] Further, the thermoplastic elastomer layer is prepared from styrene-based (SBS, SIS, SEBS, SEPS), olefin-based (TPO, TPV), diene-based (TPB, TPI), chlorovinyl-based (TPVC, TCPE), urethane-based (TPU), ester-based (TPEE), amide-based (TPAE), organic fluorine-based (TPF), silicone-based, and ethylene-based, or thermoplastic vulcanized rubber. More preferably, the layer material also contains 0.25-15wt% of sulfur or peroxide or thermosetting resin or thiourea, thiourea derivatives, or amines or bisphenols as cross-linking agents.

[0012] The rubber layer is prepared from ethylene-propylene rubber, ternary ethylene-propylene rubber, polyacrylate rubber, fluorinated carbon rubber, nitrile rubber, hydrogenated nitrile rubber, carboxyl nitrile rubber, hydrogenated carboxyl nitrile rubber, natural rubber, ethyl vinyl rubber, chlorinated polyethylene rubber, chlorosulfonyl polyethylene rubber, butyl rubber, silicone rubber, fluorosilicone rubber, chlorobutyl rubber, chloroether rubber, polyurethane rubber, isoprene rubber, cis-butadiene rubber, butadiene-styrene rubber, polyurethane rubber, chlorohydrin rubber, etc. The layer material also contains 0.25-15wt% of sulfur or peroxide or thermosetting resin or thiourea, thiourea derivatives, or amines or bisphenols as cross-linking agents.

[0013] The foamed material is mainly selected from the following three kinds:

[0014] The structural foamed material is mainly selected from PVC, PET, PMI, SAN, PEI, PI, PUR, etc.

[0015] The soft foamed material is mainly selected from foamed rubber and foamed plastic, and specifically is prepared by adding a catalyst, a foaming agent, etc. to plastic (PE, EVA, etc.) and rubber (CR, SBR, etc.) through a physical foaming or cross-linking foaming process.

[0016] The plastic soft foamed product is mainly selected from thermoplastic polyurethane (TPU), polystyrene (PS), and polyolefin.

[0017] The above-mentioned elastic layer materials are directly purchased on the market, and the inventor will not repeat them.

[0018] Compared with the prior art, the biggest improvement of the above technical scheme is that the ultra-high molecular weight polyethylene is used as the support layer material, and the preparation process of the ultra-high molecular weight polyethylene is as follows:

[0019] The wet granulation production process is as follows:

[0020] (1) The production process of modified ultra-high molecular weight polyethylene particles is as follows:

[0021] The raw material components are as follows by weight parts:

[0022] Ultra-high molecular weight polyethylene 80-100 parts, antioxidant 0.5-10 parts, disentangling agent 0-8 parts, coloring agent 0.5-5 parts, lubricant 2-15 parts, light stabilizer 0-10 parts, ultraviolet absorber 0-10 parts;

[0023] Further, the raw material components are as follows by weight parts:

[0024] Ultra-high molecular weight polyethylene 80-90 parts, antioxidant 0.5-5 parts, disentangling agent 0-4 parts, coloring agent 0.5-5 parts, lubricant 2-10 parts, light stabilizer 0-5 parts, ultraviolet absorber 0-5 parts.

[0025] The ultra-high molecular weight polyethylene selected has a viscosity average molecular weight of 1-9 million.

[0026] The antioxidant is divided into a main antioxidant and an auxiliary antioxidant, wherein the main antioxidant comprises one or more of antioxidant 264, antioxidant 1076, antioxidant CA, antioxidant 330, antioxidant MEB, antioxidant HBP, antioxidant TBM, antioxidant 3114, antioxidant 300, antioxidant 1010, antioxidant HLS, antioxidant HSS, antioxidant MMB, antioxidant DOD, antioxidant EBP, antioxidant 1024, and antioxidant 697; and the auxiliary antioxidant comprises one or more of antioxidant TNP, antioxidant TBP, antioxidant DPD, antioxidant DLTDP, and the like.

[0027] Preferably, the main antioxidant is a mixture of antioxidant 1024 and antioxidant 697 at a weight ratio of 1:1, the auxiliary antioxidant is TNP, and the mass ratio of the main antioxidant to the auxiliary antioxidant is 1-1.5:1.

[0028] The disentangling agent is selected from one or more of graphene, nanoparticles, and graphene oxide; and graphene or graphene oxide is preferably used.

[0029] The coloring agent is selected from one or more of titanium white, calcium nitrate, calcium carbonate, zinc powder (zinc oxide), cadmium red, diiron trioxide, and carbon black; and titanium white is preferably used.

[0030] The lubricant is selected from one or more of paraffin wax, polyethylene wax, chlorinated paraffin wax, natural paraffin wax, and paraffin hydrocarbon composite lubricant; and polyethylene wax is preferably used.

[0031] The light stabilizer is selected from one or more of light stabilizer 944, light stabilizer 622, light stabilizer 770, light stabilizer 783, light stabilizer 791, light stabilizer 119, light stabilizer 610, light stabilizer 611, light stabilizer P58, and light stabilizer 5229; and light stabilizer 944 or light stabilizer 610 is preferably used.

[0032] The ultraviolet absorber is selected from one or more of ultraviolet absorber 531, ultraviolet absorber UV-P, ultraviolet absorber 234, ultraviolet absorber 326, ultraviolet absorber 327, ultraviolet absorber 328, ultraviolet absorber 329, ultraviolet absorber 570, ultraviolet absorber 630, and ultraviolet absorber 237; and ultraviolet absorber 531 is preferably used.

[0033] The above raw materials are conveyed to a horizontal mixer by a screw feeder, stirred in the mixer for 5-60 minutes, and then conveyed to a bin by a screw feeder or a vacuum feeder after uniform mixing, and then subjected to double-screw extrusion.

[0034] (2) In the twin-screw extrusion process, dilute lubricant is added according to the product molecular weight and performance requirements, preferably using side feeding mode for dilute lubricant delivery, controlling the dilute lubricant flow rate, ensuring the whole system oil ratio between 10% and 90%, the dilute lubricant temperature is controlled at 30-100℃, so as to facilitate better mixing with other components, the dilute lubricant delivery speed is controlled at 10-100rpm.

[0035] Wherein when the product molecular weight is low, dilute lubricant can not be added according to actual conditions; the oil ratio can change linearly with the increase of molecular weight, that is, the amount of dilute lubricant needed also increases with the increase of molecular weight;

[0036] The dilute lubricant used above is one of white oil, decalin, paraffin oil, liquid paraffin, diphenyl ether;

[0037] (3) The dilute lubricant and the ultra-high molecular weight polyethylene raw material are extruded into a shape through a die or a spinneret by a twin-screw extruder; the temperature setting range of each heating zone of the twin-screw extruder is 180-290℃, the rotation speed of the twin-screw extruder is set at 30-200rpm, and the feeding frequency is set in the range of 2-80Hz;

[0038] Wherein the length-diameter ratio of the screw of the twin-screw extruder is set in the range of 48:1-56:1, the screw / wall gap is set at 0.1mm-1.15mm, and the screw diameter is controlled at 26mm; and the screw feeding section is designed with a conventional combination of large lead to small lead decreasing, further improving the transportation and plasticization of high molecular weight polyethylene in the feeding section, preferably, at least one shear block can be arranged on the screw, the shear block is selected from 45-degree or 60-degree or 90-degree shear block or a combination thereof, wherein when the product molecular weight is high, the 2-5 shear block mode is preferred, and the 45-degree, 60-degree and 90-degree shear block combination mode is used, and reverse shear blocks can also be arranged in the sixth to eighth intervals of the twin-screw extruder, so as to achieve better processing and plasticization effect under the premise of ensuring the molecular weight.

[0039] (4) A water ring cutter device is arranged at the die, the water ring cutter frequency is set at 5-20HZ, and the oil particles containing dilute lubricant are obtained after dehydration through a drying screen and a vibrating screen, and the oil particle diameter is 0.5-8mm.

[0040] (5) The prepared oil particles are extracted by an extractant, or the oil is pulled after extrusion through a die spinneret, cooled by air or water, extracted by an extractant, dried and then drawn and cut into particles, or cut into particles after supercritical fluid extraction.

[0041] The extraction agent is selected from one of gasoline, n-hexane, dimethylbenzene, dichloromethane, tetrachloroethane, anhydrous ethanol, methanol, acetone, or a low-boiling-point hydrocarbon; the supercritical fluid is one of carbon dioxide, nitrous oxide, methanol, ethane, ammonia, and water; the extraction agent extraction time is 0-30 min, the optimal bath ratio is 1 ml / g-100 ml / g, the drying time is 3-12 min, the drying temperature is 20-50°C; the supercritical carbon dioxide extraction; the critical temperature is set to 20-40°C, and the critical pressure is set to 1-100 MPa.

[0042] The above method is used for granulation, and the spinneret is stretched into a strip, which is easier to stretch and has a longer stretching rate, and the performance of the ultra-high molecular weight polyethylene granules is better; the advantage of supercritical carbon dioxide extraction is that it does not need to pass through an organic solvent, which can save costs and protect the environment. Meanwhile, the granules obtained by extraction in step (5) form a hollow in the middle of the granules. The product itself has a very high molecular weight, and the hardness and processing difficulty of the granules are very large. However, due to the hollow after extraction, the granules are easier to process in the subsequent process and have a certain buffering strength. In the subsequent processing into a support layer, the buffering strength is better than that of products with the same molecular weight due to the existence of the hollow.

[0043] On the basis of the above scheme, the inventors further provide a (two) ultra-high molecular weight polyethylene composite film production process as follows:

[0044] (1) The modified support layer raw material particles are conveyed to a hot air dryer with temperature control through a feeding machine and dried for 48-96 hours to remove water, and then conveyed to a composite die through a single screw extruder, a melt pipeline, a metering pump, and a screen changer; the single screw extruder has a temperature setting range of 250-290°C in different intervals, a rotation speed setting of 100-200 rpm, and a torque setting range of 100-150 Gpa;

[0045] (2) The elastic layer raw material particles are conveyed to a hot air dryer with temperature control through a feeding machine and dried for 48-96 hours to remove water, and then conveyed to a composite die through a single screw extruder, a melt pipeline, a metering pump, and a screen changer; the single screw extruder has a temperature setting range of 100-150°C in different intervals, a rotation speed setting of 50-100 rpm, and a torque setting range of 10-50 Gpa;

[0046] Due to the difference in flowability of the support layer and the elastic layer at the composite die, the torque setting of the support layer extrusion is generally controlled to be 3-10 times that of the elastic layer according to the molecular weight.

[0047] (3) Step (1) in the modified support layer raw material particles and step (2) in the elastic layer raw material particles in the composite die extrusion, get the composite film containing support layer and elastic layer, and control the thickness ratio of support layer and elastic layer is 1:1-2:1, the composite die temperature setting 270-290 ℃, the composite film extrusion angle can be selected horizontally or vertically or inclined, the extrusion width of the composite film can be between 0.2-3 m, the extrusion thickness is between 0.1-8 mm;

[0048] The composite die uses a clothes hanger type composite die, which guides the flow of plastic material by the flow channel inside the die body. The support layer and the elastic layer particles are heated to a molten state by a single screw extruder, and then the molten particles are fed into the flow channel inside the die body through the feeding port. Inside the flow channel, the material is subjected to pressure from the extrusion core rod and gradually moves forward along the flow channel. However, considering the differences in composite effect and flowability between the support layer and the elastic layer, the torque setting for extruding the support layer in the previous two steps is controlled at 3-10 times that of the elastic layer, thereby ensuring smooth composite extrusion of the material.

[0049] (4) After the composite film is extruded, it is directly fed into a multi-roller calender for extrusion and compounding. Alternatively, after longitudinal stretching, it is fed into a multi-roller calender for extrusion and compounding. The longitudinal stretching multiple can be between 0.02-50 times, the number of multi-roller calender rollers can be between 2-12, the roller temperature is set to 40-100 ℃, the roller gap is set to 0.1-5 mm, the roller diameter can be between 0.04-4 m, the roller width can be between 0.25-8 m, one or more roller surfaces can be mirror surface rollers, or a combination of mirror surface rollers and net pattern or convex point or concave point surface rollers. The net pattern includes but is not limited to one or a combination of square, diamond, or various circular or irregular shapes. The concave or convex points can be one or more combinations of cylindrical, meteor crater type, conical, or inclined ladder shape.

[0050] (5) After the composite film is stretched by the multi-roller calender, it can be directly cut and wound by the winding machine to produce the required composite film roll.

[0051] In addition, the front or back or both sides can be treated by a corona machine to meet the use requirements. The front or back or both sides can also be treated by a plasma treatment machine to meet the use requirements.

[0052] The composite film can also be treated by a gluing machine on one side. The glue type can be hot melt glue, single-component glue, or double-component glue, and the glue amount is set to 10-400 g / m 2The gluing method includes, but is not limited to, full coating, spiral coating, interval stripe coating, point coating or a combination of the above, and the release film can be attached to the surface of the glue after gluing. The release film material is selected from polyester or polyethylene, and can be colorless transparent, colored transparent, white opaque or colored opaque according to the use requirements.

[0053] In summary, the composite film prepared by the above process has good wear resistance, weather resistance and salt spray corrosion resistance, and has high anti-adhesion performance and low temperature resistance, and can maintain good performance at-60℃ to-20℃. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 A column chart for comparing the wear resistance of the ultra-high molecular weight polyethylene composite film obtained in Example 1 of the present application with other materials;

[0055] Figure 2 A column chart for comparing the impact strength of the ultra-high molecular weight polyethylene composite film obtained in Example 1 of the present application with other materials. DETAILED DESCRIPTION

[0056] The present application will be further described in conjunction with specific examples, but the present application is not limited to the following examples. The methods are conventional methods unless otherwise specified. In the following examples and experimental examples, various raw materials are commercially available unless otherwise specified.

[0057] Example 1:

[0058] A preparation process of ultra-high molecular weight polyethylene, the specific steps are as follows:

[0059] (1) 100 parts of ultra-high molecular weight polyethylene with a molecular weight of 2 million or more, 3 parts of polyethylene wax, and 4 parts of titanium dioxide are selected by weight and mixed uniformly in a high mixer. After mixing uniformly, 0.15 parts of antioxidant 1024, 0.15 parts of antioxidant 697 and 0.15 parts of antioxidant TNP are added and mixed uniformly in the high mixer. The raw materials are conveyed to the horizontal mixer by the screw feeder, and stirred in the mixer for 15 minutes. After the material is mixed uniformly, it is conveyed to the silo by the screw feeder or the vacuum feeder, and then extruded by the double screw extruder.

[0060] The oil particles containing dilution lubricant are obtained by the following twin-screw extruder with screw combination, the temperature of each interval is set as follows: 210℃, 230℃, 250℃ (a 45° shear block is installed in this interval), 250℃, 275℃, 275℃, 280℃, 280℃, 280℃, and the white oil at about 70℃ is added as dilution lubricant in the first 250℃ interval by side feeding to ensure that the oil ratio in the system is 5%, the dilution lubricant conveying speed is controlled at 10 rpm, the die temperature is set at 280℃, the screw speed is 80 rpm, the feeding frequency is set at 13 Hz, the screw length-diameter ratio is set in the range of 48:1, the screw / wall gap is set at 0.1 mm, and the screw diameter is controlled at 26 mm.

[0061] (2) The water ring cutter device is provided at the die, and the water ring cutter frequency is set at 10 Hz. After being dried by a fan and screened by a vibrating screen, the oil particles containing dilution lubricant are obtained.

[0062] (3) The prepared oil particles are extracted by the extracting agent dichloromethane (or supercritical carbon dioxide) to obtain modified UPE particles. The extraction time is 30 min, the optimal bath ratio for extraction is 30 ml / g, the drying time is 10 min, and the drying temperature is 40℃. The supercritical carbon dioxide extraction; the critical temperature is set at 40℃, and the critical pressure is set at 12 MPa.

[0063] Example 2

[0064] A preparation process of ultra-high molecular weight polyethylene, the specific steps are as follows:

[0065] (1) 100 parts of ultra-high molecular weight polyethylene with a molecular weight of more than 3 million, 5 parts of polyethylene wax, 5 parts of titanium dioxide are selected by weight, and are mixed uniformly in a high mixer. After mixing uniformly, 0.1 parts of antioxidant 1024, 0.1 parts of antioxidant 697, antioxidant TNP 0.1 parts, and 1 part of graphene are added and mixed uniformly in the high mixer. Each raw material is conveyed to a horizontal mixer by a screw feeder, and stirred in the mixer for 30 minutes. After the material is mixed uniformly, it is conveyed to a silo by a screw feeder or a vacuum feeder, and then subjected to double-screw extrusion.

[0066] The extrusion granulation is carried out by a twin-screw extruder with the following screw combination, and the temperature of each interval is set in turn as follows: 210°C, 230°C, 250°C (a 45° shear block is installed in this interval), 250°C, 275°C (a 60° shear block is installed in this interval), 275°C, 280°C (a 45° shear block is installed in this interval), 280°C, 280°C, and the white oil at about 70°C is added as a dilution lubricant in the second 250°C interval by a side feeding mode, so as to ensure that the oil ratio in the system is 20%, the dilution lubricant conveying speed is controlled at 40 rpm, the die temperature is set at 280°C, the screw rotating speed is 80 rpm, the feeding frequency is set at 13 Hz, the screw length-diameter ratio is set in the range of 48:1, the screw / wall gap is set at 0.1 mm, and the screw diameter is controlled at 26 mm.

[0067] (2) The water ring cutter device is provided at the die, and the water ring cutter frequency is set at 10 Hz. After being dried by a fan and screened by a vibrating screen, the oil particles containing the dilution lubricant are obtained.

[0068] (3) The oil is drawn after being extruded through the die spinneret, extracted by the extracting agent dichloromethane, dried, and then drawn and cut into particles. The extraction time is 30 min, the optimal bath ratio for extraction is 30 ml / g, the drying time is 10 min, and the drying temperature is 40°C. After being cooled by air or water, the modified UPE particles are prepared. The drawing speed is selected as 75 m / min, the cutting speed is selected as 30 Hz, and the rotating speed is set as 240 rpm.

[0069] Example 3

[0070] A preparation process of ultra-high molecular weight polyethylene, and the specific steps are as follows:

[0071] (1) 100 parts of ultra-high molecular weight polyethylene with a molecular weight of more than 8 million, 10 parts of polyethylene wax, 5 parts of titanium dioxide are selected by weight, and are mixed uniformly in a high-speed mixer. After being mixed uniformly, 0.15 parts of antioxidant 1024, 0.15 parts of antioxidant 697, antioxidant TNP 0.15 parts, and 3 parts of graphene are added, and are mixed uniformly in the high-speed mixer. The raw materials are conveyed to a horizontal mixer by a screw feeder, and are stirred in the mixer for 30 minutes. After the materials are uniformly mixed, they are conveyed to a silo by a screw feeder or a vacuum feeder, and are subjected to double-screw extrusion.

[0072] The UPE pellets prepared in Examples 1-3 are subjected to molecular weight detection, and the results are shown in the following table. It can be seen that the molecular weight attenuation degree of the UPE pellets prepared by the examples of the present application is smaller, while the molecular weight attenuation degree of the UPE pellets prepared by the ordinary granulation method in the art is larger. There is no great difference in the mechanical properties. Compared with Example 1, Examples 2 and 3 add an appropriate amount of disentangling agent, and at the same time, the oil ratio of the dilution lubricant is increased, which is more conducive to the processing of high molecular weight polyethylene. Compared with the ultra-high molecular weight polyethylene pellets obtained by the above-mentioned ordinary granulation method, the molecular weight attenuation degree is smaller, the pellets can still maintain a high molecular weight characteristic, the process is more optimized, the energy consumption is smaller, and the processing performance of the obtained pellets is generally better than that of ordinary pellets.

[0073] (2) The water ring cutter device is provided at the die head, and the water ring cutter frequency is set to 8 Hz. After drying by a fan and screening, oil pellets containing dilution lubricant are obtained.

[0074] (3) The oil is drawn after being extruded through the die head spinneret, extracted by the extraction agent dichloromethane, dried, and then drawn and cut into pellets. The extraction time is 30 min, the optimal bath ratio is 30 ml / g, the drying time is 10 min, and the drying temperature is 40°C. After air or water cooling, modified UPE pellets are prepared. The drawing speed is selected to be 75 m / min, the cutting speed is selected to be 20 Hz, and the rotation speed is set to be 200 rpm.

[0075] The UPE pellets prepared in Examples 1-3 are subjected to molecular weight detection, and the results are shown in the following table. It can be seen that the molecular weight attenuation degree of the UPE pellets prepared by the examples of the present application is smaller, while the molecular weight attenuation degree of the UPE pellets prepared by the ordinary granulation method in the art is larger. There is no great difference in the mechanical properties. Compared with Example 1, Examples 2 and 3 add an appropriate amount of disentangling agent, and at the same time, the oil ratio of the dilution lubricant is increased, which is more conducive to the processing of high molecular weight polyethylene. Compared with the ultra-high molecular weight polyethylene pellets obtained by the above-mentioned ordinary granulation method, the molecular weight attenuation degree is smaller, the pellets can still maintain a high molecular weight characteristic, the process is more optimized, the energy consumption is smaller, and the processing performance of the obtained pellets is generally better than that of ordinary pellets.

[0076] Table of molecular weight attenuation of ultra-high molecular weight polyethylene pellets

[0077]

[0078] Example 4

[0079] A production process of an ultra-high molecular weight polyethylene composite film is as follows:

[0080] (1) The modified UPE particles obtained in Example 1 are fed as support layer raw material particles to a hot air dryer with temperature control through a feeder and dried for 48 hours to remove moisture, and then pass through a single screw extruder 1, a melt pipeline, a metering pump and a screen changer, and finally are fed to a composite die; the temperature of different sections of the single screw extruder is set to be in the range of 250-290°C, the rotation speed is set to be 100 rpm, and the torque range is set to be 150 Gpa;

[0081] (2) The elastic layer raw material particles (the elastic layer material particles in this example are selected from thermoplastic polyurethane (TPU) particles) are fed to a hot air dryer with temperature control through a feeder and dried for 48 hours to remove moisture, and then pass through a single screw extruder 2, a melt pipeline, a metering pump and a screen changer, and finally are fed to a composite die; the temperature of different sections of the single screw extruder is set to be in the range of 100-150°C, the rotation speed is set to be 50 rpm, and the torque range is set to be 50 Gpa;

[0082] (3) The support layer raw material particles in step (1) and the elastic layer raw material particles in step (2) are selected according to the thickness ratio of the support layer to the elastic layer being 1:1, and are extruded at the same time in a composite die to obtain a composite film containing a support layer and an elastic layer; the temperature of the composite die is set to be 150-290°C, the extrusion angle of the composite film can be selected to be vertical, the extrusion width of the composite film can be 0.2 m, and the extrusion thickness is 0.1 mm;

[0083] (4) After the composite film is extruded, it is directly fed into a conventional multi-roller calender for extrusion and compounding, the number of multi-roller calender rollers is 3, the roller temperatures are set to be 80°C, 60°C and 30°C in sequence, and the finished film can be obtained by winding.

[0084] The inventors have carried out relevant performance tests on the composite film finally obtained in this example, and the results are shown in the following table:

[0085]

[0086] The mechanical properties of the product obtained by the tensile strength and elongation at break in the above table are obviously better than those of the same molecular weight of the ultra-high molecular weight polyethylene particles, because the composite film contains an elastic layer in the compounding process, which ensures that the composite film has the ultra-strong rigidity of the ultra-high molecular weight polyethylene and also has the elasticity of the elastic layer, and is more suitable for use in complex and harsh environments. The 90° peeling strength mainly shows the bonding strength between the elastic layer and the matrix resin, which ensures that the protective film and the protected matrix will not be separated in harsh environments, and the support layer and the elastic layer will not be cracked during the peeling process, which verifies the compounding effect of the elastic layer and the support layer.

[0087] Comparison of anti-attachment performance of ultra-high molecular weight polyethylene composite films

[0088]

[0089]

[0090] The above anti-attachment performance comparison results show that the anti-attachment performance of the ultra-high molecular weight polyethylene composite film obtained by the application is close to that of polytetrafluoroethylene, which is currently known to have the best anti-attachment performance, and also has anti-attachment performance that equal materials do not have, has obvious effects on wind turbine blade protection and marine microbial attachment, and has more excellent performance advantages in wind turbine blade protection.

[0091] At the same time, the wear resistance and impact strength comparison results of the obtained composite film with other materials are shown in Figure 1 and 2 . As shown in Figure 1 , the ultra-high molecular weight polyethylene molecular chain in the application has a relatively long length, so it has excellent wear resistance, which is better than various existing materials; at the same time, the inventors tested the wear loss of the above composite film, and the results are shown in the following table:

[0092]

[0093] It can be seen that the UHMWPE composite film obtained by the application has better wear resistance, and the mass loss is less than that of the UHMWPE ordinary particle film prepared by the existing conventional method; by Figure 2 , the impact strength of the UHMWPE composite film finally obtained by the application reaches 186kJ / m 2 , which is higher than that of other existing materials.

[0094] The inventors also conducted an anti-ultraviolet performance test, and the surface did not crack or age after ultraviolet irradiation for 5000 hours. Performance tests were conducted, and the test results compared with high-density polyethylene film are as follows:

[0095]

[0096] As can be seen from the above table, no light stabilizer and ultraviolet absorber is added in the particles in Example 1, but the finally obtained composite film still has good anti-aging ability, which is obviously better than the existing HDPE film with the same molecular weight; therefore, after adding light stabilizer and ultraviolet absorber on the basis of the technical solution of Example 1, the anti-aging performance of the finally obtained composite film will be more excellent, and it is more suitable for long-term application in complex and harsh environments. Therefore, light stabilizer and ultraviolet absorber only need to be added appropriately when needed.

[0097] Meanwhile, the content in the above table also shows that the mechanical properties of the obtained composite film are more excellent compared to the mechanical properties of other materials, and the material still maintains good mechanical properties after 5000 hours of thermal oxygen aging, indicating that the stability of the composite film is better than that of other materials, and is more suitable for long-term use in complex environments.

[0098] The above examples show and describe the basic principles, product features and advantages of the method of the present application. The present application is not limited by the above examples, and various changes and improvements can be made without departing from the scope of the present application, and all are required to be included in the scope of protection.

Claims

1. A wet-process composite membrane of ultra-high molecular weight polyethylene, comprising a support layer and an elastic layer, characterized in that: The support layer is made of ultra-high molecular weight polyethylene, and the elastic layer is one or more of thermoplastic elastic layer, rubber layer, and foam layer; wherein the thickness ratio of the support layer to the elastic layer is 1:1-2:

1. The specific steps of the preparation process for the ultra-high molecular weight polyethylene are as follows: (1) The production process of modified ultra-high molecular weight polyethylene granules is as follows: The raw material components, by weight, are as follows: 80-100 parts of ultra-high molecular weight polyethylene, 0.5-10 parts of antioxidant, 0-8 parts of detangling agent, 0.5-5 parts of colorant, 2-15 parts of lubricant, 0-10 parts of light stabilizer, and 0-10 parts of ultraviolet absorber; The ultra-high molecular weight polyethylene used therein has a viscosity-average molecular weight between 1 million and 9 million. The above raw materials are conveyed to the horizontal mixer by a screw feeder and stirred in the mixer for 5-60 minutes. After the materials are mixed evenly, they are conveyed to the hopper by a screw feeder or vacuum feeder for twin-screw extrusion. (2) During the twin-screw extrusion process, diluent is added to the twin-screw extruder according to the molecular weight and performance requirements of the product. The diluent is conveyed by side feeding, the flow rate of the diluent is controlled, the oil-to-material ratio of the whole system is kept between 10% and 90%, the temperature of the diluent is controlled between 30℃ and 100℃, and the conveying speed of the diluent is controlled between 10 and 100 rpm. (3) The diluted lubricant and ultra-high molecular weight polyethylene raw material are extruded through a die or spinneret by a twin-screw extruder; the temperature setting range of each heating zone of the twin-screw extruder is 180℃-290℃, the speed setting of the twin-screw extruder is 30-200rpm, and the feeding frequency setting range is 2-80Hz. (4) A water ring cutter device is provided at the die head. The frequency of the water ring cutter is set to 5-20HZ. After dehydration by the drying screen and vibrating screen, oil particles containing diluted lubricant are obtained. The diameter of the oil particles is 0.5-8mm. (5) The prepared oil particles are extracted with an extractant, or the oil is extruded through a die spinneret and then pulled, cooled by air or water, extracted with an extractant, dried and then pulled into strips and granulated. The diluent used in step (2) is one of white oil, decahydronaphthalene, liquid paraffin, or diphenyl ether; The screw length-to-diameter ratio of the twin-screw extruder described in step (3) is set in the range of 48:1-56:1, the screw / wall clearance is set in the range of 0.1mm-1.15mm, and the screw diameter is controlled at 26mm; at least one shearing block is provided on the screw, and the shearing block is selected from 45-degree, 60-degree, or 90-degree shearing blocks or combinations thereof.

2. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1, characterized in that: The raw material components, by weight, are as follows: 80-90 parts of ultra-high molecular weight polyethylene, 0.5-5 parts of antioxidant, 0-4 parts of detangling agent, 0.5-5 parts of colorant, 2-10 parts of lubricant, 0-5 parts of light stabilizer, and 0-5 parts of ultraviolet absorber.

3. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1, characterized in that: Antioxidants are classified into primary antioxidants and secondary antioxidants. Primary antioxidants include one or more of the following: antioxidant 264, antioxidant 1076, antioxidant CA, antioxidant 330, antioxidant MEB, antioxidant HBP, antioxidant TBM, antioxidant 3114, antioxidant 300, antioxidant 1010, antioxidant HLS, antioxidant HSS, antioxidant MMB, antioxidant DOD, antioxidant EBP, antioxidant 1024, and antioxidant 697. Secondary antioxidants include one or more of the following: antioxidant TNP, antioxidant TBP, antioxidant DPD, and antioxidant DLTDP. The untangling agent is selected from one or more of graphene and graphene oxide; The colorant is selected from one or more of titanium dioxide, calcium nitrate, calcium carbonate, zinc oxide, cadmium red, ferric oxide, and carbon black; The lubricant is selected from one or more of paraffin wax, polyethylene wax, chlorinated paraffin wax, and natural paraffin wax; The light stabilizer is selected from one of the following: light stabilizer 944, light stabilizer 622, light stabilizer 770, light stabilizer 783, light stabilizer 791, light stabilizer 119, light stabilizer 610, and light stabilizer P58. The ultraviolet absorber is selected from one of ultraviolet absorber 531, ultraviolet absorber UV-P, ultraviolet absorber 234, ultraviolet absorber 326, ultraviolet absorber 327, ultraviolet absorber 328, ultraviolet absorber 329, ultraviolet absorber 570, ultraviolet absorber 630, and ultraviolet absorber 237.

4. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1 or 2, characterized in that: The primary antioxidant is a mixture of primary antioxidant 1024 and primary antioxidant 697 in a 1:1 weight ratio; the secondary antioxidant is TNP, and the mass ratio of primary antioxidant to secondary antioxidant is 1-1.5:1; the detangling agent is graphene or graphene oxide; the colorant is titanium dioxide; the lubricant is polyethylene wax; the light stabilizer is selected from light stabilizer 944 or light stabilizer 610; and the ultraviolet absorber is selected from ultraviolet absorber 531.

5. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1, characterized in that: In step (5), the extraction method uses one of the following: gasoline, n-hexane, xylene, dichloromethane, tetrachloroethane, anhydrous ethanol, methanol, and acetone. The extraction time is 0-30 min, the optimal extraction bath ratio is 1 ml / g-100 ml / g, the drying time is 3-12 min, and the drying temperature is 20℃-50℃.

6. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1, characterized in that: In step (5), the extraction method is supercritical fluid extraction. The supercritical fluid is one of carbon dioxide, nitrous oxide, methanol, ethane, or water. The critical temperature is set to 20-40℃ and the critical pressure is set to 1MPa-100MPa.

7. The ultra-high molecular weight polyethylene wet-process composite film according to claim 1, characterized in that: The production process of the ultra-high molecular weight polyethylene wet-process composite film is as follows: (1) The modified support layer raw material particles are fed into a hot air dryer with temperature control and dried for 48-96 hours to remove moisture. Then, they are fed into a single screw extruder, melt pipeline, metering pump and screen changer, and finally delivered to the composite die head. The temperature setting range of different zones of the single screw extruder is between 250℃ and 290℃, the speed is set to 100-200 rpm, and the torque range is set to 100-150 Gpa. (2) The elastic layer raw material particles are fed into a hot air dryer with temperature control and dried for 48-96 hours to remove moisture. Then, they are fed into a single screw extruder, melt pipeline, metering pump and screen changer, and finally delivered to the composite die head. The temperature setting range of different zones of the single screw extruder is between 100℃ and 150℃, the speed is set to 50-100 rpm, and the torque range is set to 10-50 Gpa. The torque setting during the extrusion of the support layer is controlled at 3-10 times the molecular weight of the elastic layer. (3) The modified support layer raw material particles in step (1) and the elastic layer raw material particles in step (2) are extruded simultaneously in the composite die to obtain a composite film containing a support layer and an elastic layer. The thickness ratio of the support layer to the elastic layer is controlled to be 1:1-2:

1. The temperature of the composite die is set to 270℃-290℃. The extrusion angle of the composite film is selected to be horizontal, vertical or inclined. The extrusion width of the composite film is between 0.2-3m and the extrusion thickness is between 0.1-8mm. (4) The composite film is directly fed into a multi-roll calender for extrusion and lamination after extrusion; or it is longitudinally stretched and then fed into a multi-roll calender for extrusion and lamination. (5) After the composite film is calendered by multiple rollers, it is directly cut and wound by a winding machine to produce the required composite film roll.

8. The ultra-high molecular weight polyethylene wet-process composite film according to claim 7, characterized in that: The composite die head mentioned in step (3) is a coat hanger type composite die head; the longitudinal stretching ratio in step (4) is between 0.02 and 50 times, the number of multi-roll calendering rollers is between 2 and 12, the roller temperature is set to 40℃-100℃, the roller gap is set to 0.1-5mm, the roller diameter is between 0.04-4m, and the roller width is between 0.25-8m.

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