An ultra-high molecular weight polyethylene plate and a preparation method and application thereof

Abstract

The application provides an ultrahigh molecular weight polyethylene plate and a preparation method and application thereof, and belongs to the technical field of polymer material forming. The ultrahigh molecular weight polyethylene melt blank is cut in different directions and stacked, and the cut stacked melt blank is heat-pressed and oriented; through repeated cutting, stacking and heat-pressing, the orientation degree can be improved without reducing the thickness of the plate, so that the wear resistance and mechanical properties are enhanced. The ultrahigh molecular weight polyethylene plate prepared by the application has excellent wear resistance and mechanical properties, can be applied in the field of wear-resistant parts with high stress level requirements, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer material forming, and particularly relates to a kind of ultra-high molecular weight polyethylene plate and its preparation method and application. BACKGROUND

[0002] Ultra-high molecular weight polyethylene (UHMWPE) generally refers to polyethylene with a molecular weight of more than 1.5 million, which has excellent impact resistance, wear resistance and biocompatibility, and is widely used in various fields, especially in the field of orthopedics, and is the main material of artificial knee joint and hip joint prosthesis. However, the particles generated by the wear of joint prosthesis under long-term cyclic stress loading conditions can cause osteolysis and aseptic loosening, resulting in the reduction of the service life of artificial joints. In order to reduce the revision and replacement of high molecular joint prosthesis and alleviate the pain and economic burden of patients undergoing joint replacement, it is necessary to further improve the wear resistance of high molecular materials.

[0003] Preparation of oriented self-reinforced plate is an effective method to improve wear resistance and mechanical properties, and has been deeply studied in UHMWPE film and fiber products. However, due to the thickness or width reduction caused by the stretching orientation process, it is difficult to efficiently prepare UHMWPE plate with certain thickness and high orientation by traditional orientation process. In addition, the orientation direction has an impact on the wear resistance of the plate product, and the wear resistance along the orientation direction is improved, while the wear resistance perpendicular to the orientation direction is reduced. With the trend of younger patients undergoing joint replacement, higher requirements are put forward for the mechanical strength and friction and wear properties of UHMWPE materials. Therefore, how to prepare high wear resistance and high strength ultra-high molecular weight polyethylene plate with certain thickness and high orientation has become a difficult problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to provide a kind of ultra-high molecular weight polyethylene plate and its preparation method and application. The preparation method provided by the present application can prepare a kind of high wear resistance and high strength ultra-high molecular weight polyethylene plate with certain thickness and high orientation.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0006] The present application provides a kind of ultra-high molecular weight polyethylene plate and its preparation method and application.

[0007] (1) First heat pressing of ultra-high molecular weight polyethylene powder to obtain a melt blank;

[0008] (2) The melt blank obtained in step (1) is cut in half and stacked, and then second heat pressing is carried out to obtain a uniaxial oriented melt blank;

[0009] or the melt blank obtained in the step (1) is cut in half, stacked, and then subjected to a second heat pressing to obtain a uniaxially oriented melt blank; then the obtained uniaxially oriented melt blank is cut in half along a direction perpendicular to the cutting direction of the melt blank cut in half, stacked, and then subjected to a third heat pressing to obtain a biaxially oriented melt blank;

[0010] The sizes of the uniaxially oriented melt blank and the biaxially oriented melt blank are independently the same as the size of the melt blank obtained in the step (1);

[0011] (3) repeating the operation of the step (2) to obtain a layer of uniaxially oriented melt blank or a layer of biaxially oriented melt blank;

[0012] (4) cooling and setting the layer of uniaxially oriented melt blank or the layer of biaxially oriented melt blank obtained in the step (3) to obtain a UHMWPE plate.

[0013] Preferably, the UHMWPE powder in the step (1) has a viscosity-average molecular weight of 2 million to 10 million.

[0014] Preferably, the temperature of the first heat pressing in the step (1), the second heat pressing and the third heat pressing in the step (2) is independently 150-250℃, and the time of the first heat pressing, the second heat pressing and the third heat pressing is independently 1-60 min.

[0015] Preferably, the second heat pressing and the third heat pressing in the step (2) are independently carried out in a static force field or a pulsating force field.

[0016] Preferably, the pressure of the static force field is 5-50 MPa.

[0017] Preferably, the frequency of the pulsating force field is 0.1-10 Hz, and the pressure of the pulsating force field is 0-50 MPa.

[0018] Preferably, the waveform of the pulsating force field is a sine wave, a square wave or a triangular wave.

[0019] Preferably, the cooling rate of the cooling and setting in the step (4) is 5-10℃ / min.

[0020] The application also provides a UHMWPE plate prepared by the preparation method.

[0021] The application also provides an application of the UHMWPE plate in wear-resistant parts.

[0022] The application provides a preparation method of an ultra-high molecular weight polyethylene plate, comprising the following steps: first hot pressing of an ultra-high molecular weight polyethylene powder to obtain a melt blank; after the melt blank is cut in half, the cut melt blanks are stacked and then second hot pressing is performed to obtain a uniaxially oriented melt blank; or after the melt blank is cut in half, the cut melt blanks are stacked and then second hot pressing is performed to obtain a uniaxially oriented melt blank; then the obtained uniaxially oriented melt blank is cut in half along the vertical direction of the cutting direction of the melt blank, the cut melt blanks are stacked and then third hot pressing is performed to obtain a biaxially oriented melt blank; the sizes of the uniaxially oriented melt blank and the biaxially oriented melt blank are independently the same as the size of the melt blank; the operation of cutting in half and stacking is repeated and then hot pressing is performed to obtain a uniaxially oriented melt blank layer or a biaxially oriented melt blank layer; the uniaxially oriented melt blank layer or the biaxially oriented melt blank layer is cooled and shaped to obtain an ultra-high molecular weight polyethylene plate.

[0023] The application cuts and stacks the ultra-high molecular weight polyethylene melt blank in different directions, and hot presses the cut and stacked melt blank, so that the orientation degree is increased without reducing the thickness of the plate, and the wear resistance and mechanical properties are enhanced. DETAILED DESCRIPTION

[0024] The application provides a preparation method of an ultra-high molecular weight polyethylene plate, comprising the following steps:

[0025] (1) first hot pressing of an ultra-high molecular weight polyethylene powder to obtain a melt blank;

[0026] (2) after the melt blank obtained in the step (1) is cut in half, the cut melt blanks are stacked and then second hot pressing is performed to obtain a uniaxially oriented melt blank;

[0027] or after the melt blank obtained in the step (1) is cut in half, the cut melt blanks are stacked and then second hot pressing is performed to obtain a uniaxially oriented melt blank; then the obtained uniaxially oriented melt blank is cut in half along the vertical direction of the cutting direction of the melt blank, the cut melt blanks are stacked and then third hot pressing is performed to obtain a biaxially oriented melt blank;

[0028] the sizes of the uniaxially oriented melt blank and the biaxially oriented melt blank are independently the same as the size of the melt blank obtained in the step (1);

[0029] (3) the operation of the step (2) is repeated to obtain a uniaxially oriented melt blank layer or a biaxially oriented melt blank layer;

[0030] (4) the uniaxially oriented melt blank layer or the biaxially oriented melt blank layer obtained in the step (3) is cooled and shaped to obtain an ultra-high molecular weight polyethylene plate.

[0031] The "first hot pressing", "second hot pressing" and "third hot pressing" in the present application are only for distinguishing the hot pressing in each step, and the "first", "second" and "third" have no special meaning.

[0032] In the present application, the ultrahigh molecular weight polyethylene powder is subjected to the first hot pressing to obtain a melt blank.

[0033] In the present application, the viscosity average molecular weight of the ultrahigh molecular weight polyethylene powder is preferably 2 million to 10 million, further preferably 3 million to 8 million, and more preferably 5 million. The present application has no special limitation on the source of the ultrahigh molecular weight polyethylene powder, and a commercially available product known to those skilled in the art can be used.

[0034] In the present application, the temperature of the first hot pressing is preferably 150 to 250℃, and more preferably 155 to 210℃; the time of the first hot pressing is preferably 1 to 60 min, further preferably 5 to 50 min, and more preferably 5 to 10 min; the first hot pressing is preferably performed in a static force field or a pulsating force field; the pressure of the static force field is preferably 5 to 50 MPa, and more preferably 10 to 20 MPa; the waveform of the pressure-time curve of the pulsating force field is preferably a sine wave, a square wave or a triangular wave, and more preferably a sine wave; the frequency of the pulsating force field is preferably 0.1 to 10 Hz, and more preferably 5 to 8 Hz; and the pressure of the pulsating force field is preferably 0 to 50 MPa, and more preferably 15 ± 5 MPa. The present application can make the raw material uniformly melt by controlling the process parameters of the first hot pressing.

[0035] In the present application, the first hot pressing is preferably performed in a square non-spill mold. The present application has no special limitation on the model of the square non-spill mold, which can be adjusted according to actual needs. The present application has no special limitation on the amount of the ultrahigh molecular weight polyethylene powder, which can be adjusted according to the size of the desired product.

[0036] After obtaining the melt blank, the present application cuts the melt blank in half, stacks it, and then performs the second hot pressing to obtain a uniaxially oriented melt blank. The present application cuts the melt blank in half along a single direction, and according to the cutting direction, the melt blank will be oriented in the direction perpendicular to the cutting direction, thereby obtaining a uniaxially oriented melt blank.

[0037] The present application has no special limitation on the operation of cutting in half, which can be operated according to the conventional operation.

[0038] The present application has no special limitation on the operation of stacking, as long as the melt blank cut in half is completely overlapped from top to bottom.

[0039] In the present application, the second hot pressing is preferably carried out in a static force field or a pulsating force field; the pressure of the static force field is preferably 5-50 MPa, more preferably 10-20 MPa; the waveform of the pulsating force field is preferably a sine wave, a square wave or a triangular wave, more preferably a sine wave; the frequency of the pulsating force field is preferably 0.1-10 Hz, more preferably 2-5 Hz; the pressure of the pulsating force field is preferably 0-50 MPa, more preferably 10±10 MPa; the temperature of the second hot pressing is preferably 150-250°C, more preferably 155-200°C; the time of the second hot pressing is preferably 1-60 min, more preferably 2-50 min, more preferably 2-10 min.

[0040] In the present application, the second hot pressing is preferably carried out in a square non-spilling mold, more preferably in the central position of the square non-spilling mold; the square non-spilling mold is preferably the same as the mold used in the first hot pressing.

[0041] In the present application, the size of the uniaxially oriented melt blank is preferably the same as that of the melt blank. By controlling the size of the uniaxially oriented melt blank to be the same as that of the melt blank, the present application can ensure that the plate has a certain thickness, thereby increasing the orientation degree without reducing the thickness of the plate.

[0042] After obtaining the melt blank, the present application cuts the melt blank in half, stacks the cut pieces, and then carries out the second hot pressing to obtain a uniaxially oriented melt blank. Then, the obtained uniaxially oriented melt blank is cut in half along the vertical direction of the cutting direction of the melt blank, stacked, and then subjected to the third hot pressing to obtain a biaxially oriented melt blank. By cutting the melt blank in half along a single direction and then cutting it in half along the vertical direction, the melt blank will be oriented along both cutting directions, thereby obtaining a biaxially oriented melt blank.

[0043] In the present application, the operation of cutting the melt blank in half, stacking the cut pieces, and then carrying out the second hot pressing to obtain a uniaxially oriented melt blank is preferably the same as the operation described above for preparing a uniaxially oriented melt blank, and will not be repeated here.

[0044] The operation of cutting the melt blank in half along the vertical direction of the cutting direction of the melt blank and then stacking the cut pieces is not particularly limited and can be performed according to the conventional method. By controlling the cutting direction of the cutting in half, the present application can ensure that the melt blank is biaxially oriented after subsequent hot pressing.

[0045] In the present application, the operation of the third hot pressing is preferably the same as that of the second hot pressing, and will not be repeated here.

[0046] In the present application, the size of the biaxially oriented melt blank is preferably the same as that of the melt blank. The present application can ensure a certain thickness of the plate by controlling the size of the biaxially oriented melt blank to be the same as that of the melt blank, thereby improving the orientation degree without reducing the thickness of the plate.

[0047] After obtaining the uniaxially oriented melt blank, the present application repeats the foregoing operation of preparing the uniaxially oriented melt blank to obtain a layer of uniaxially oriented melt blank. The present application can improve the orientation degree without reducing the thickness of the plate by repeated cutting, layering and hot pressing, thereby enhancing the wear resistance and mechanical properties.

[0048] In the present application, the number of repetitions is preferably 1-12, further preferably 2-5, and more preferably 2 times. The present application can further improve the orientation degree by controlling the number of repetitions, thereby further enhancing the wear resistance and mechanical properties.

[0049] After obtaining the biaxially oriented melt blank, the present application repeats the foregoing operation of preparing the biaxially oriented melt blank to obtain a layer of biaxially oriented melt blank. The present application can improve the orientation degree without reducing the thickness of the plate by repeated cutting, layering and hot pressing, thereby enhancing the wear resistance and mechanical properties.

[0050] In the present application, the number of repetitions is preferably 1-12, further preferably 2-5, and more preferably 2 times. The present application can further improve the orientation degree by controlling the number of repetitions, thereby further enhancing the wear resistance and mechanical properties.

[0051] After obtaining the layer of uniaxially oriented melt blank or the layer of biaxially oriented melt blank, the present application cools and shapes the layer of uniaxially oriented melt blank or the layer of biaxially oriented melt blank to obtain an ultra-high molecular weight polyethylene plate. The present application can fix the orientation of the molecular chain segments in the blank layer by cooling and shaping, thereby further improving the wear resistance and mechanical properties.

[0052] In the present application, the pressure of the cooling and shaping is preferably 0.1-50 MPa, further preferably 20-40 MPa, and more preferably 20-30 MPa; and the cooling rate of the cooling and shaping is preferably 5-10 ℃ / min, and more preferably 8.5 ℃ / min.

[0053] The present application cuts and layers the ultra-high molecular weight polyethylene melt blank in different directions, and hot-presses the cut and layered melt blank to orient. The present application can improve the orientation degree without reducing the thickness of the plate by repeated cutting, layering and hot pressing, thereby enhancing the wear resistance and mechanical properties.

[0054] The application can prepare uniaxially oriented and biaxially oriented high wear-resistant self-reinforced ultra-high molecular weight polyethylene plate by repeatedly cutting and stacking the ultra-high molecular weight polyethylene melt blank and repeatedly hot-pressing and orienting the cut and stacked melt blank by using a pulsating force field or a static force field; the orientation degree can be increased without reducing the thickness of the plate by increasing the number of cutting, stacking and hot-pressing and orienting, so that the wear resistance and mechanical properties are enhanced; the ultra-high molecular weight polyethylene plate prepared by the application has excellent mechanical properties and wear resistance and can be applied in the field of wear-resistant parts with high stress level, and has good application prospect.

[0055] The application further provides the ultra-high molecular weight polyethylene plate prepared by the preparation method.

[0056] The application further provides the application of the ultra-high molecular weight polyethylene plate in wear-resistant parts.

[0057] The technical solutions in the application will be clearly and completely described below with reference to the embodiments in the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0058] Embodiment 1

[0059] A preparation method of a biaxially oriented ultra-high molecular weight polyethylene plate comprises the following steps:

[0060] (1) UHMWPE powder with a viscosity-average molecular weight of 5 million is poured into a square non-overflow mold to perform first hot-pressing to obtain a melt blank; wherein the temperature of the first hot-pressing is 155℃, and the time is 5 min; the first hot-pressing is performed in a sinusoidal wave pulsating force field; the frequency of the pulsating force field is 5 Hz, and the pressure is 15±5 MPa;

[0061] (2) the melt blank obtained in the step (1) is cut in half and stacked, and then placed in the central position of the square non-overflow mold to perform second hot-pressing to obtain a uniaxially oriented melt blank; then the obtained uniaxially oriented melt blank is cut in half along the vertical direction of the cutting direction of the melt blank cut in half and stacked, and then placed in the central position of the square non-overflow mold to perform third hot-pressing to obtain a biaxially oriented melt blank; wherein the temperature of the second hot-pressing and the third hot-pressing is 155℃, and the time is 2 min; the second hot-pressing and the third hot-pressing are both performed in a sinusoidal wave pulsating force field; the frequency of the pulsating force field is 2 Hz, and the pressure is 10±10 MPa; the size of the biaxially oriented melt blank is the same as that of the melt blank obtained in the step (1);

[0062] (3) repeating the operation of step (2) 2 times to obtain a biaxially oriented melt blank layer with a biaxial stretching ratio of 8x8 and 64 layers of stretching orientation;

[0063] (4) cooling and setting the biaxially oriented melt blank layer obtained in step (3) at a cooling rate of 8.5℃ / min under a pressure of 20 MPa to obtain a biaxially oriented ultra-high molecular weight polyethylene plate with a thickness of 4 mm.

[0064] The biaxially oriented ultra-high molecular weight polyethylene plate prepared in Example 1 was subjected to 3 times of operation of step (2) during preparation, and the tensile properties and tribological properties of the plate were tested. The tensile properties were tested according to standard GB / T1040.2-2022, and the tribological properties were tested according to ASTM G99. The tensile strength was 170.8 MPa, and the volume wear rate was 1.76x10 -5 mm 3 / Nm.

[0065] Example 2

[0066] On the basis of Example 1, the second heat pressing and the third heat pressing were both set to be carried out in a static force field. The pressure of the static force field was 20 MPa, and other conditions were unchanged. A biaxially oriented ultra-high molecular weight polyethylene plate with a thickness of 4 mm was obtained.

[0067] The biaxially oriented ultra-high molecular weight polyethylene plate prepared in Example 2 was subjected to tensile property and tribological property tests. The tensile strength was 153.3 MPa, and the volume wear rate was 2.48x10 -5 mm 3 / Nm.

[0068] Example 3

[0069] On the basis of Example 1, the temperature of the first heat pressing, the second heat pressing and the third heat pressing were all set to 150℃, and other conditions were unchanged. A biaxially oriented ultra-high molecular weight polyethylene plate with a thickness of 4 mm was obtained.

[0070] The biaxially oriented ultra-high molecular weight polyethylene plate prepared in Example 3 was subjected to tensile property and tribological property tests. The tensile strength was 183.1 MPa, and the volume wear rate was 2.26x10 -5 mm 3 / Nm.

[0071] Example 4

[0072] On the basis of Example 1, the number of repetitions of step (3) was set to 1 time to obtain a biaxially oriented melt blank layer with a biaxial stretching ratio of 4x4 and 16 layers of stretching orientation, and other conditions were unchanged. A biaxially oriented ultra-high molecular weight polyethylene plate with a thickness of 4 mm was obtained.

[0073] The biaxially oriented UHMWPE plate prepared in Example 4 was subjected to tensile property and tribological property tests, and the tensile strength of the plate was 79.7 MPa, and the volume wear rate was 2.82 x 10 -5 mm 3 / Nm.

[0074] Example 5

[0075] On the basis of Example 1, step (2) was set as follows: the melt blank obtained in step (1) was cut in half and then stacked, and was placed in the central position of a square non-overflowing mold, and was then subjected to a second hot pressing to obtain a uniaxially oriented melt blank; then a uniaxially oriented melt blank layer having a uniaxial stretching ratio of 8 and having 8 layers of stretched orientation was obtained, and other conditions were unchanged, and a uniaxially oriented UHMWPE plate having a thickness of 4 mm was obtained.

[0076] The uniaxially oriented UHMWPE plate prepared in Example 5 was subjected to tensile property and tribological property tests, and the tensile strength in the orientation direction was 130.5 MPa, and the volume wear rate was 2.21 x 10 -5 mm 3 / Nm.

[0077] Example 6

[0078] On the basis of Example 1, the temperature of the first hot pressing was set to 210°C, and other conditions were unchanged, and a biaxially oriented UHMWPE plate having a thickness of 4 mm was obtained.

[0079] The biaxially oriented UHMWPE plate prepared in Example 6 was subjected to tensile property and tribological property tests, and the tensile strength was 176.8 MPa, and the volume wear rate was 1.55 x 10 -5 mm 3 / Nm.

[0080] Comparative Example 1

[0081] A method for preparing a UHMWPE plate that is not subjected to cutting and stacking and hot pressing for orientation, and the method comprises the following steps:

[0082] (1) UHMWPE powder having a viscosity average molecular weight of 5 million was poured into a square non-overflowing mold, and was subjected to a first hot pressing to obtain a melt blank; wherein the temperature of the first hot pressing was 210°C, and the time was 5 min; the first hot pressing was performed in a sinusoidal wave pulse vibration force field; the frequency of the pulse vibration force field was 5 Hz, and the pressure was 15 ± 5 MPa;

[0083] (2) The melt blank melt obtained in step (1) is subjected to hot pressing at a static pressure of 20 MPa at 210 ℃ for 30 min, and then cooled and shaped at a rate of 8.5 ℃ / min under a pressure of 20 MPa to obtain a 4-mm-thick non-stretching oriented ultra-high molecular weight polyethylene plate.

[0084] The ultra-high molecular weight polyethylene plate prepared in Comparative Example 1 is subjected to tensile property and tribological property tests, and the tensile strength is 37.1 MPa, and the volume wear rate is 6.48 x 10 -5 mm 3 / Nm.

[0085] As can be seen from the above examples and comparative examples, the preparation method provided by the present application can prepare a high-wear-resistance high-strength ultra-high molecular weight polyethylene plate with a certain thickness and high orientation.

[0086] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of protection of the present application.

Claims

1. A method for preparing an ultra-high molecular weight polyethylene plate, comprising the following steps: (1) subjecting an ultra-high molecular weight polyethylene powder to a first heat pressing to obtain a melt blank; (2) stacking the melt blank obtained in step (1) after cutting it in half and then subjecting it to a second heat pressing to obtain a uniaxially oriented melt blank; or stacking the melt blank obtained in step (1) after cutting it in half and then subjecting it to a second heat pressing to obtain a uniaxially oriented melt blank; and then cutting the obtained uniaxially oriented melt blank in half along a direction perpendicular to the cutting direction of the melt blank and then stacking the obtained melt blanks and subjecting them to a third heat pressing to obtain a biaxially oriented melt blank; wherein the uniaxially oriented melt blank and the biaxially oriented melt blank have the same size as the melt blank obtained in step (1); (3) repeating the operation of step (2) to obtain a layer of uniaxially oriented melt blank or a layer of biaxially oriented melt blank; (4) subjecting the layer of uniaxially oriented melt blank or the layer of biaxially oriented melt blank obtained in step (3) to a cooling and setting to obtain an ultra-high molecular weight polyethylene plate; wherein the second heat pressing and the third heat pressing in step (2) are carried out in a pulsating force field. The ultra-high molecular weight polyethylene powder in step (1) has a viscosity average molecular weight of 2 million to 10 million. The temperature of the first heat pressing in step (1), the second heat pressing and the third heat pressing in step (2) is independently 150 to 250℃, and the time of the first heat pressing, the second heat pressing and the third heat pressing is independently 1 to 60 minutes. The frequency of the pulsating force field is 0.1 to 10 Hz, and the pressure of the pulsating force field is 0 to 50 MPa. The waveform of the pulsating force field is a sine wave, a square wave or a triangular wave. The cooling rate of the cooling and setting in step (4) is 5 to 10℃ / min.

7. An ultra-high molecular weight polyethylene plate prepared by the method of any one of claims 1 to 6.

8. Use of the ultra-high molecular weight polyethylene plate of claim 7 in wear-resistant parts.

2. The production method according to claim 1, characterized by, ​ 3. The production method according to claim 1, characterized by, ​ 4. The method of claim 1, wherein, ​ 5. The production method according to claim 1 or 4, characterized by, ​ 6. The method of claim 1, wherein, ​ ​ ​