Extrusion plasticizing forming system

Abstract

The utility model belongs to the field of polymer waterproof coiled materials, and discloses an extrusion plasticizing forming system which comprises a charging barrel, a double-shaft eccentric rotor extrusion plasticizing subsystem, a sheet forming mold, three-roller calendering equipment and a sheet winding device. According to the utility model, the extensional rheology technology is adopted, and the double-shaft eccentric rotor extrusion plasticizing subsystem is specially designed, so that molecular chain breakage can be avoided, and the viscosity average molecular weight retention rate of the ultra-high molecular weight polyethylene resin sheet is high.

Description

Technical Field

[0001] The utility model belongs to the field of polymer waterproof coiled materials, and more specifically, relates to a system for extrusion plasticization molding. Background Art

[0002] Currently, polymer waterproof coiled materials mainly use PVC, EPDM, TPO, and HDPE as the main raw materials, and are applied to underground waterproof projects and roof waterproofing. Among them, high-density polyethylene is one of the most commonly used materials, and usually adopts a single-screw extrusion processing technology. The viscosity-average molecular weight of the polyethylene resin used for making waterproof boards is less than 1 million, the melt mass flow rate is generally higher than 0.1 g / 10 min, and the melting point is lower than 135 °C.

[0003] For ultra-high molecular weight polyethylene with a viscosity-average molecular weight higher than 1 million, due to the easy entanglement of molecular chains, it has excellent physical properties:

[0004] (1) High wear resistance and self-lubrication: Ultra-high molecular weight polyethylene has self-lubrication second only to polytetrafluoroethylene and has a very small friction coefficient. Its wear resistance is the best among all current engineering plastics, and its wear resistance is 10 times that of PVC-U and HDPE.

[0005] (2) Low-temperature resistance, impact resistance, and corrosion resistance: Ultra-high molecular weight polyethylene still has high impact resistance at low temperatures, and is especially suitable for applications in cold regions. For ultra-high molecular weight polyethylene pipes, the service life under strong corrosion and high wear conditions is 4-6 times that of steel pipes.

[0006] Due to the ultra-long molecular chain structure and high entanglement density of ultra-high molecular weight polyethylene, it has the characteristic of being difficult to process. The melt mass flow rate is 0, and it also shows high viscoelasticity when heated to the melting temperature. The relationship between the melt viscosity and the viscosity-average molecular weight can be expressed by the following formula, where k is a constant, M wc is the critical viscosity-average molecular weight. When the viscosity-average molecular weight is higher than the critical viscosity-average molecular weight, the physical cross-linking formed by the entanglement of molecular chains makes the melt viscosity increase. Generally, the viscosity-average molecular weight of polymers is much larger than M wc , and from the formula, it can be obtained that when the viscosity-average molecular weight is 10 times higher, the viscosity is 2000 times higher.

[0007] η = kMw (Mw < Mwc);

[0008]

[0009] It is very difficult to process using the single and double screw extruders commonly used to process ordinary HDPE. At the same time, due to its very small friction coefficient, it is easy to slip on the screw wall. It shows a high elastic state between the melting point and the decomposition temperature, and if the heating time is too long, the material will be oxidized and degraded.

[0010] Using traditional screw processing methods mainly based on shear flow fields, HDPE, LDPE, LLDPE with medium to low viscosity average molecular weight can be blended and modified with ultra-high molecular weight polyethylene, or other processing aids can be added to improve the melt fluidity, so as to carry out extrusion processing. Anisotropic screws can also be used to forcibly convey the melt. However, due to excessive shear force, the molecular weight of the extruded material drops by about 40%, and the performance drops significantly. There are also documents proposing to use a disk-shaped force chemical reactor with strong shear force for processing, but this will cause a serious drop in molecular weight, making the molecular weight of the product far lower than the original molecular weight of the ultra-high molecular weight resin, so that the product does not have the high strength and impact resistance physical properties that ultra-high molecular weight polyethylene should have. The processing of ultra-high molecular weight polyethylene can also use methods such as compression molding, ram extrusion, injection molding, and blow molding. The high shear force generated by the above processing equipment will cause molecular chain breakage. On the other hand, the long thermal mechanical process causes thermal oxidative decomposition of the material.

[0011] Table 1 Performance data of high-density polyethylene with different viscosity average molecular weights

[0012]

[0013] Therefore, there is an urgent need to propose a new extrusion plasticizing and forming system at present. Utility Model Content

[0014] The purpose of the present utility model is to address the deficiencies of the prior art and propose an extrusion plasticizing and forming system. The present utility model adopts stretching rheology technology and specially designs the twin-shaft eccentric rotor extrusion plasticizing subsystem, which can avoid molecular chain breakage and maintain a high viscosity average molecular weight retention rate of ultra-high molecular weight polyethylene resin sheets.

[0015] To achieve the above purpose, the present utility model provides an extrusion plasticizing and forming system, and the extrusion plasticizing and forming system includes a barrel, a twin-shaft eccentric rotor extrusion plasticizing subsystem, a sheet forming die, a three-roll calendering device, and a sheet winding device;

[0016] The twin-shaft eccentric rotor extrusion plasticizing subsystem includes two meshing eccentric rotors and a stator. The eccentric rotor includes a plurality of eccentric spiral structures and eccentric cylindrical structures, and includes a feeding section, a melting and plasticizing section, and a melt conveying section that are sequentially connected from the feeding end to the discharging end;

[0017] The feeding section includes an eccentric screw-free rotor;

[0018] The melting and plasticizing section includes a first rotor combination section with gradually decreasing pitch, a straight extrusion strengthening section, and a reflux section that are sequentially connected;

[0019] The melt conveying section includes a first melt conveying section, a second melt conveying section connected in sequence, and a second rotor combination section with a gradually decreasing pitch.

[0020] The spiral direction of the reflux section is opposite to that of other sections of the eccentric rotor.

[0021] Preferably, the diameter of the eccentric rotor is 20 - 120 mm.

[0022] Preferably, the compression ratio of the eccentric rotor is 2 - 2.8:1.

[0023] Preferably, the length - diameter ratio of the eccentric rotor is 38 - 45:1.

[0024] Preferably, the melting and plasticizing section is multi - section, and the number of sections, length, and the length - diameter ratio of the rotor combination are determined according to the viscosity - average molecular weight of the resin to be extruded and plasticized.

[0025] Preferably, the melt conveying section is multi - section, and the number of sections, length, and the length - diameter ratio of the rotor combination are determined according to the viscosity - average molecular weight of the resin to be extruded and plasticized.

[0026] Preferably, the eccentric rotor contains pins.

[0027] Preferably, the die lip of the sheet forming die is a flat - mouth structure die lip, and the thickness perpendicular to the sheet extrusion direction of the flat - mouth structure die lip is 2 - 20 cm.

[0028] Preferably, the sheet forming die is provided with an electric heating heat source and a plurality of temperature sensors. The plurality of temperature sensors are arranged along the direction parallel to the die lip, and the electric heating heat source is connected to the plurality of temperature sensors for realizing zone heating in the runner of the sheet forming die.

[0029] Preferably, the distance between the die orifice of the sheet forming die and the three - roll calendering equipment is 5 - 300 mm.

[0030] The beneficial effects of the technical solution of the present utility model are as follows:

[0031] The present utility model adopts the stretching rheology technology and makes a special design for the biaxial eccentric rotor extrusion and plasticization subsystem (eccentric rotor), which can avoid the breakage of molecular chains, keep the viscosity - average molecular weight retention rate of the ultra - high molecular weight polyethylene resin sheet high. At the same time, the system of the present utility model can make the processing technology energy - saving and efficient, adopt a barrel temperature equivalent to that of the current high - density polyethylene sheet processing, and achieve an extrusion efficiency equivalent to that of processing high - density polyethylene sheets. Through the system of the present utility model, a flexible waterproof coil with high temperature resistance, high puncture strength, high wear resistance, high strength, and high toughness can be prepared.

[0032] The extrusion and plasticizing forming system of the present utility model can be used to produce ultra-high molecular weight polyethylene resin sheets. The raw materials of the sheets include ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 800,000 to 9,000,000. The viscosity-average molecular weight of the sheets is not less than 80% of the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin.

[0033] Other features and advantages of the present utility model will be described in detail in the subsequent specific implementation section. Brief Description of the Drawings

[0034] By describing the exemplary embodiments of the present utility model in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present utility model will become more obvious. Among them, in the exemplary embodiments of the present utility model, the same reference numerals generally represent the same components.

[0035] Figure 1 The schematic diagram of the eccentric rotor of the twin-shaft eccentric rotor extrusion and plasticizing subsystem of the extrusion and plasticizing forming system provided in Embodiment 1 of the present utility model is shown.

[0036] Figure 2 The side view of the sheet forming die of a high-density polyethylene extrusion system in the prior art is shown.

[0037] Figure 3 The side view of the sheet forming die of the extrusion and plasticizing forming system provided in Embodiment 1 of the present utility model is shown.

[0038] Figure 4 The schematic diagram of the extrusion and plasticizing forming system provided in Embodiment 1 of the present utility model is shown.

[0039] Figure 5 The front view of the sheet forming die of the extrusion and plasticizing forming system provided in Embodiment 1 of the present utility model is shown.

[0040] Figure 6(a) shows the schematic diagram of the flow of UHMW-PE melt coming out of the die lip of the sheet forming die of the extrusion and plasticizing forming system provided in Embodiment 1 of the present invention.

[0041] Figure 6(b) shows the schematic diagram of the flow of PE melt coming out of the die lip of the sheet forming die of the extrusion and plasticizing forming system provided in Embodiment 1 of the present invention.

[0042] The descriptions of the reference numerals in the drawings are as follows:

[0043] 1 - Spout - shaped die lip, 2 - Flat - mouth structure die lip, 3 - Melt pump, 4 - Sheet forming die, 5 - Three - roll calendering equipment, 6 - Sheet winding device, 7 - Electric heating heat source, 8 - Temperature sensor socket, F - Melt extrusion die lip acting force, D - Melt flow direction, 9 - UHMW - PE melt, 10 - PE melt. Detailed implementation mode

[0044] The preferred implementation modes of the present utility model will be described in more detail below. Although the preferred implementation modes of the present utility model are described below, it should be understood that the present utility model can be implemented in various forms and should not be limited by the implementation modes described herein. On the contrary, these implementation modes are provided to make the present utility model more thorough and complete, and to be able to fully convey the scope of the present utility model to those skilled in the art.

[0045] The present utility model provides an extrusion and plasticizing forming system, and the extrusion and plasticizing forming system includes a barrel, a twin - shaft eccentric rotor extrusion and plasticizing subsystem, a sheet forming die, a three - roll calendering equipment, and a sheet winding device;

[0046] The twin - shaft eccentric rotor extrusion and plasticizing subsystem includes two meshing eccentric rotors and a stator. The eccentric rotor includes a plurality of eccentric spiral structures and eccentric cylindrical structures, and includes a feeding section, a melting and plasticizing section, and a melt conveying section that are sequentially connected from the feeding end to the discharging end;

[0047] The feeding section includes an eccentric - free threaded rotor;

[0048] The melting and plasticizing section includes a first rotor combination section with gradually decreasing pitch, a straight extrusion strengthening section, and a reflux section that are sequentially connected;

[0049] The melt conveying section includes a first melt conveying section, a second melt conveying section, and a second rotor combination section with gradually decreasing pitch that are sequentially connected;

[0050] The spiral direction of the reflux section is opposite to that of other sections of the eccentric rotor.

[0051] In the present utility model, an ultra - high - molecular - weight polyethylene resin sheet can be prepared by using the extrusion and plasticizing forming system of the present utility model. The raw material of the sheet includes an ultra - high - molecular - weight polyethylene resin with a viscosity - average molecular weight of 800,000 to 9,000,000; the viscosity - average molecular weight of the sheet is not less than 80% of the viscosity - average molecular weight of the ultra - high - molecular - weight polyethylene resin.

[0052] The thickness of the sheet can be 0.1 - 2.0 mm.

[0053] The raw materials of the sheet may further include ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 800,000 to 9,000,000, other polymer resins, processing aids, and pigments and fillers; and based on the total weight of the sheet, the content of the ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 800,000 to 9,000,000 is 55-100%, and the total content of other polymer resins, processing aids, and pigments and fillers is 0-45%.

[0054] The processing aid is a processing aid for improving lubrication performance, which improves the surface quality of the calendered sheet.

[0055] In one example, the diameter of the eccentric rotor is 20-120 mm.

[0056] In one example, the compression ratio of the eccentric rotor is 2-2.8:1. (The compression ratio is the ratio of the volume of the first screw groove in the feeding section to the volume of the last screw groove in the melt conveying section.)

[0057] In one example, the length-diameter ratio of the eccentric rotor is 38-45:1.

[0058] In one example, the molten plasticizing section is multi-segmented, and the number of segments, length, and the combined length-diameter ratio of the rotors are determined according to the viscosity-average molecular weight of the resin to be extruded and plasticized. In the present invention, the molten plasticizing sections are connected by a third connecting section.

[0059] In one example, the melt conveying section is multi-segmented, and the number of segments, length, and the combined length-diameter ratio of the rotors are determined according to the viscosity-average molecular weight of the resin to be extruded and plasticized.

[0060] In one example, the eccentric rotor contains pins.

[0061] In the present invention, as a preferred solution, as Figure 1 shown:

[0062] The feeding section includes a pre-feeding section, a first connecting section, an eccentric-free threaded rotor, and a second connecting section connected in sequence;

[0063] According to an embodiment of the present invention, the length of the pre-feeding section is 22-26 mm, and the pitch is 6-10 mm.

[0064] According to an embodiment of the present invention, the lengths of the first connecting section and the second connecting section are each independently 8-12 mm.

[0065] According to an embodiment of the present invention, there are multiple eccentric-free threaded rotors, and the length of each eccentric-free threaded rotor is 30-120 mm, and the pitch is 20-60 mm.

[0066] According to an embodiment of the present utility model, each of the first rotor combined section with gradually decreasing pitch and the second rotor combined section with gradually decreasing pitch is independently a combined section composed of at least four of the first pitch section, the second pitch section, the third pitch section, the fourth pitch section, and the fifth pitch section, and there are multiple of each pitch section;

[0067] The length of the first pitch section is 34 - 38 mm, and the pitch is 34 - 38 mm;

[0068] The length of the second pitch section is 30 - 33 mm, and the pitch is 30 - 33 mm;

[0069] The length of the third pitch section is 22 - 25 mm, and the pitch is 22 - 25 mm;

[0070] The length of the fourth pitch section is 36 - 42 mm, and the pitch is 18 - 21 mm;

[0071] The length of the fifth pitch section is 28 - 32 mm, and the pitch is 12 - 17 mm;

[0072] According to an embodiment of the present utility model, the length of the third connection section is 22 - 26 mm, and the pitch is 6 - 10 mm.

[0073] According to an embodiment of the present utility model, the lengths of the first melt conveying section and the second melt conveying section are independently 22 - 26 mm, and the pitches are independently 6 - 10 mm.

[0074] According to an embodiment of the present utility model, the length of the reflux section is 20 - 100 mm, the pitch is 3 - 60 mm, the rotation direction is opposite to that of the above eccentric rotor, and the depth of the screw groove between each screw rib is 1 - 50 mm.

[0075] According to the present utility model, preferably, there are multiple straight extrusion strengthening sections, the length of each straight extrusion strengthening section is 20 - 120 mm, the pitch is 5 - 60 mm, and the depth of the screw groove between each screw rib is 2 - 5 mm.

[0076] In a specific embodiment of the present utility model, the structure of each eccentric rotor is as Figure 1 shown in Table 2.

[0077] The pre - feeding section corresponds to T45 - 24 - Q8 - 0A;

[0078] Both the first connection section and the second connection section correspond to T45 - G10DP - 0A;

[0079] The non - eccentric screw rotor corresponds to 4 T45 - 40 - D40 - 0A;

[0080] The first rotor combination section with a gradually decreasing pitch in the first melting and plasticizing section corresponds to a combination section composed of five pitch sections of T45-36-P36-0A, T45-32-P32-0A, T45-24-P24-0A, T45-40-P20-0A, and T45-30-P15-0A. Among them, there are 3 of T45-36-P36-0A; 2 of T45-32-P32-0A; 1 of T45-24-P24-0A; 4 of T45-40-P20-0A; and 3 of T45-30-P15-0A.

[0081] The straight extrusion strengthening section corresponds to 3 of T45-30-KP180-3-0A;

[0082] The reflux section corresponds to 1 of T45-30-KP180-3-0B.

[0083] The third connection section corresponds to T45-24-P8-0A;

[0084] Both the first melt conveying section and the second melt conveying section correspond to T45-24-P8-0A;

[0085] Table 2

[0086]

[0087]

[0088] In one example, the die lip of the sheet forming die is a flat mouth structure die lip, and the thickness of the flat mouth structure die lip perpendicular to the sheet extrusion direction is 2-20 cm.

[0089] In one example, an electric heating heat source and a plurality of temperature sensors are arranged on the sheet forming die. The plurality of temperature sensors are arranged along a direction parallel to the die lip, and the electric heating heat source is connected to the plurality of temperature sensors for realizing zonal heating in the runner of the sheet forming die.

[0090] In one embodiment of the present utility model, as Figure 5 shown, through the electric heating heat source and the plurality of temperature sensors, a plurality of regions are obtained. Each region has a temperature sensor socket, so that the temperatures of region 5-1 and region 5-5 are set higher than those of the central region 5-3, and the temperatures of the sub-central regions 5-2 and 5-4 are in the middle. The die has the function of zonal heating, further solving the problem that the fluidity of the UHMW-PE melt in the runner is affected by uneven temperature. As a preferred solution, the temperatures of region 5-1 and region 5-5 are 180 °C, the temperatures of the sub-central regions 5-2 and 5-4 are 170 °C, and the temperature of the central region 5-3 is 160 °C.

[0091] In one example, the distance between the die orifice of the sheet forming die and the three-roll calendering equipment is 5 - 300 mm.

[0092] In the present utility model, the method for preparing the above-mentioned ultra-high molecular weight polyethylene resin sheet includes: feeding the raw materials of the sheet into the twin-screw eccentric rotor extrusion and plasticizing subsystem from the feeding section, after extrusion and plasticization by the first rotor combination section with gradually decreasing pitch and the straight extrusion and strengthening section, material reflux is generated by the reflux section to strengthen extrusion plasticization and compaction; finally, after achieving the uniformity of melt temperature, pressure and plasticization degree in the melt conveying section, it is fed into the sheet forming die; the melt coming out from the die lip of the sheet forming die is subjected to three-roll calendering and winding treatment to obtain the sheet.

[0093] In the present utility model, through the design of extrusion plasticization and forming die, the processing difficulty of poor fluidity of ultra-high molecular weight polyethylene resin is overcome, and problems such as high processing temperature and long thermal shear history in the traditional processing method are improved, the processing temperature range is broadened, extrusion can be carried out under the condition of lower than 240 °C, the sagging of the melt when it comes out of the die orifice is not obvious, it has stiffness, and the retention rate of the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin sheet is not less than 80%, that is, the viscosity-average molecular weight of the sheet is not less than 80% of the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin. Specifically:

[0094] (1) In the present utility model, the principle of realizing the stretching rheology technology by the twin-screw eccentric rotor extrusion and plasticizing subsystem is as follows:

[0095] Feeding section: An eccentric-free thread section with large shear force is adopted to achieve rapid feeding of raw materials.

[0096] First melting and plasticizing section: It includes the first rotor combination section with gradually decreasing pitch, and then is connected to a straight extrusion and strengthening section. The straight screw edges contained in the straight extrusion and strengthening section can perform enhanced extrusion on the material, improve the plasticization property, and help the UHMW-PE (ultra-high molecular weight polyethylene) resin to unwind. The reflux section has a spiral direction opposite to that of the rotors in other sections of the eccentric rotor, which helps the material to generate reflux, helps the material to be compacted, and further strengthens the plasticization and unwinding of UHMW-PE in this extrusion section.

[0097] Second melting and plasticizing section and third melting and plasticizing section: Repeat the process similar to the first melting and plasticizing section, including the rotor combination with gradually decreasing pitch, and then is connected to a straight extrusion and strengthening section. The screw edges contained in the straight extrusion and strengthening section can further realize the plasticization and unwinding of UHMW-PE. Generally speaking, the higher the viscosity-average molecular weight of UHMW-PE, the more the number of melting and plasticizing sections should be, and the longer the length of the eccentric rotor combination should be.

[0098] Melt conveying section: After undergoing the plasticization process in 3 melting and plasticizing sections, the melt temperature, pressure, and degree of plasticization are not uniform enough. To ensure the uniformity of the final formed material, it is necessary to further perform melt uniformity treatment on the material in the melt conveying section. The melt conveying section is the second rotor combination section with a gradually decreasing pitch, and finally enters the stage of the sheet forming die, which can help the material maintain a compacted state before entering the sheet forming die.

[0099] The twin-shaft eccentric rotor extrusion and plasticization subsystem of the present utility model enables the ultra-high molecular weight polyethylene resin to be fully plasticized without being subjected to high shear force and a long thermal history time. The viscosity-average molecular weight of the extruded sheet does not decrease significantly with the increase of the main machine speed, ensuring that the viscosity-average molecular weight retention rate of the sheet is not less than 80%, that is, the viscosity-average molecular weight of the sheet is not less than 80% of the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin.

[0100] (2) At the same time, the present utility model also makes a special design for the die lip of the sheet forming die. Specifically:

[0101] For the die lip of the sheet forming die in the existing common high-density polyethylene extrusion system, see Figure 2 , its die lip is designed in a pointed shape. Due to the melt expansion effect of the ultra-high molecular weight polyethylene when it exits the die lip, the die lip is squeezed and deformed, making it difficult to ensure uniform transverse thickness;

[0102] Therefore, the present utility model can design the die lip opening into a flat shape (i.e., a flat-mouth structure), see Figure 3 . The thickness of the metal material perpendicular to the sheet extrusion direction at the die lip is large, so the strength is high and it is not easily squeezed and deformed. The vertical pressure of the melt is not enough to cause the die lip to deform. Because the melt strength of the ultra-high molecular weight polyethylene is high, the melt (UHMW-PE) still has strength and stiffness after exiting the die lip. Therefore, generally, the die lip does not need to be directly attached to the surface of the pressure roller (as shown in Fig. 6(a)). After the melt exits the die lip and is roll-pressed by the pressure roller, the sheet thickness can be made uniform and the surface flatness can be improved. Generally, the ultra-high molecular weight melt has poor fluidity and high strength, and the calender roll should not be too cold. Maintaining a certain temperature can help the ultra-high molecular weight polyethylene sheet to be calendered into shape.

[0103] In the preparation method of the ultra-high molecular weight polyethylene resin sheet, the temperature of each section of the eccentric rotor of the twin-shaft eccentric rotor extrusion and plasticization subsystem is set below 240 °C, preferably 160 - 220 °C.

[0104] In the preparation method of the ultra-high molecular weight polyethylene resin sheet, the extrusion amount of the twin-shaft eccentric rotor extrusion and plasticization subsystem is 0.2 - 12 kg / min. In the present utility model, the extrusion amount of the twin-shaft eccentric rotor extrusion and plasticization subsystem has a low correlation with the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin.

[0105] In the method for preparing a ultra-high molecular weight polyethylene resin sheet, the rotational speed of the eccentric rotor of the twin-screw eccentric rotor extrusion and plasticization subsystem is 5 - 300 revolutions per minute.

[0106] In the method for preparing a ultra-high molecular weight polyethylene resin sheet, the temperature of the three-roll calendering equipment is 20 - 200 °C, preferably 70 °C - 150 °C.

[0107] The ultra-high molecular weight polyethylene resin sheet prepared by using the extrusion and plasticization forming system of the present utility model can be applied in waterproof coiled materials. And the waterproof coiled materials prepared from this ultra-high molecular weight polyethylene resin sheet generally have high temperature resistance in high temperature environments (it can withstand a maximum long-term temperature of 90 °C), high wear resistance, high strength, and high puncture resistance.

[0108] Specifically, a waterproof coiled material, the waterproof coiled material includes a ultra-high molecular weight polyethylene resin sheet and a functional layer provided on the upper surface of the ultra-high molecular weight polyethylene resin sheet;

[0109] The ultra-high molecular weight polyethylene resin sheet is the ultra-high molecular weight polyethylene resin sheet prepared by using the extrusion and plasticization forming system of the present utility model;

[0110] The functional layer includes a hot melt adhesive layer and a weather-resistant anti-sticking coating; the ultra-high molecular weight polyethylene resin sheet, the hot melt adhesive layer, and the weather-resistant anti-sticking coating are arranged in sequence from top to bottom; or, the functional layer is at least one of a PVDF film, a PVF film, and a weather-resistant metal foil coated with a weather-resistant coating; or, the functional layer is an upper self-adhesive layer;

[0111] Optionally, a lower self-adhesive layer is provided on the lower surface of the ultra-high molecular weight polyethylene resin sheet;

[0112] Preferably, the thickness of the hot melt adhesive layer is 0.2 - 1.5 mm;

[0113] Preferably, the thicknesses of the upper self-adhesive layer and the lower self-adhesive layer are each independently 0.2 - 1.5 mm.

[0114] As a preferred solution, the waterproof coiled material is a pre-laid and self-adhesive ultra-high molecular weight waterproof coiled material, and the pre-laid and self-adhesive ultra-high molecular weight waterproof coiled material includes a ultra-high molecular weight polyethylene resin sheet, a hot melt adhesive layer, and a weather-resistant anti-sticking coating arranged in sequence from top to bottom. The pre-laid and self-adhesive ultra-high molecular weight waterproof coiled material has high wear resistance and puncture resistance, and can meet the construction requirements without a protective layer after construction.

[0115] As a preferred solution, the waterproof coiled material is a pre-laid and self-adhered ultra-high molecular weight waterproof coiled material, which includes a lower self-adhesive layer, an ultra-high molecular weight polyethylene resin sheet, a hot melt adhesive layer, and a weather-resistant anti-sticking coating arranged in sequence from top to bottom. The pre-laid and self-adhered ultra-high molecular weight waterproof coiled material has high wear resistance and puncture resistance, and can meet the construction requirements without a protective layer after construction.

[0116] As a preferred solution, the waterproof coiled material is an exposed self-adhesive ultra-high molecular weight polyethylene waterproof coiled material, which includes a lower self-adhesive layer, an ultra-high molecular weight polyethylene resin sheet, and an exposed functional layer arranged in sequence from top to bottom. The exposed functional layer is at least one of a PVDF film, a PVF film, and a weather-resistant metal foil coated with a weather-resistant coating. Preferably, the weather-resistant metal foil coated with a weather-resistant coating is a weather-resistant aluminum foil.

[0117] As a preferred solution, the waterproof coiled material is a self-adhesive waterproof coiled material, which includes an ultra-high molecular weight polyethylene resin sheet and an upper self-adhesive layer arranged in sequence from top to bottom. The self-adhesive waterproof coiled material has high wear resistance and puncture resistance, and can meet the construction requirements without a protective layer after construction.

[0118] By using ultra-high molecular weight polyethylene resin with a molecular weight of 800,000 - 9,000,000, the thickness of the coiled material is reduced by 10 - 50%, and the strength performance is equivalent to that of HDPE. It not only saves materials and reduces the burden on buildings, but also has important significance for building energy conservation and emission reduction. At the same time, it improves the softness of the waterproof coiled material, improves the construction convenience, and has important significance for the improvement of the waterproof construction quality.

[0119] Through the structural design of the waterproof coiled material, a series of waterproof coiled materials and auxiliary materials based on ultra-high molecular weight polyethylene are developed, which have high temperature resistance, high puncture strength, high wear resistance, high strength and high toughness, as well as high temperature service environment, and improve the performance level of building waterproof materials.

[0120] In the following various examples and comparative examples:

[0121] The viscosity-average molecular weight is measured according to GB / T 1632.3-2010 (Test method for measuring the viscosity of polymer dilute solutions by capillary viscometer).

[0122] Example 1

[0123] This example provides an extrusion and plasticizing molding system, which includes a barrel, a twin-shaft eccentric rotor extrusion and plasticizing subsystem, a sheet molding die, a three-roll calendering device 5, and a sheet winding device 6;

[0124] The biaxial eccentric rotor extrusion and plasticization subsystem includes two meshing eccentric rotors and a stator. The eccentric rotor includes a plurality of eccentric spiral structures and eccentric cylindrical structures. As Figure 1 shown in Table 2, each eccentric rotor includes a feeding section, a melting and plasticization section, and a melt conveying section connected in sequence from the feeding end to the discharging end;

[0125] The feeding section includes a pre-feeding section, a first connecting section, an eccentric-free threaded rotor, and a second connecting section connected in sequence; the pre-feeding section corresponds to T45-24-Q8-0A; both the first connecting section and the second connecting section correspond to T45-G10DP-0A; the eccentric-free threaded rotor corresponds to 4 T45-40-D40-0A;

[0126] The melting and plasticization section includes a first melting and plasticization section, a second melting and plasticization section, and a third melting and plasticization section connected in sequence. Each melting and plasticization section includes a first rotor combination section with gradually decreasing pitch, a straight extrusion strengthening section, and a reflux section connected in sequence; the melting and plasticization sections are connected by a third connecting section;

[0127] The first rotor combination section with gradually decreasing pitch in the first melting and plasticization section corresponds to a combination section composed of five pitch sections of T45-36-P36-0A, T45-32-P32-0A, T45-24-P24-0A, T45-40-P20-0A, and T45-30-P15-0A, and there are 3 T45-36-P36-0A; 2 T45-32-P32-0A; 1 T45-24-P24-0A; 4 T45-40-P20-0A; and 3 T45-30-P15-0A.

[0128] The first rotor combination section with gradually decreasing pitch in the second melting and plasticization section corresponds to a combination section composed of four pitch sections of T45-32-P32-0A, T45-24-P24-0A, T45-40-P20-0A, and T45-30-P15-0A, and there are 2 T45-32-P32-0A; 1 T45-24-P24-0A; 3 T45-40-P20-0A; and 1 T45-30-P15-0A.

[0129] The first rotor combination section with gradually decreasing pitch in the third melting and plasticization section corresponds to a combination section composed of four pitch sections of T45-36-P36-0A, T45-32-P32-0A, T45-40-P20-0A, and T45-30-P15-0A, and there are 2 T45-36-P36-0A; 1 T45-32-P32-0A; 3 T45-40-P20-0A; and 1 T45-30-P15-0A.

[0130] The straight extrusion strengthening section corresponds to three T45-30-KP180-3-0A;

[0131] The reflux section corresponds to one T45-30-KP180-3-0B.

[0132] The third connection section corresponds to T45-24-P8-0A;

[0133] The melt conveying section includes a first melt conveying section, a second melt conveying section, and a second rotor combination section with a gradually decreasing pitch connected in sequence; both the first melt conveying section and the second melt conveying section correspond to T45-24-P8-0A;

[0134] The second rotor combination section with a gradually decreasing pitch corresponds to a combination section composed of four pitch sections of T45-36-P36-0A, T45-24-P24-0A, T45-40-P20-0A, and T45-30-P15-0A, and there are 2 of T45-36-P36-0A; 1 of T45-24-P24-0A; 2 of T45-40-P20-0A; and 4 of T45-30-P15-0A.

[0135] The die lip of the sheet forming die 4 is a flat die lip 2, and the thickness of the flat die lip 2 is 6 cm;

[0136] An electric heating heat source 7 and a plurality of temperature sensors are arranged on the sheet forming die. The plurality of temperature sensors are arranged in a direction parallel to the die lip. The electric heating heat source 7 is connected to the plurality of temperature sensors for realizing zonal heating in the flow channel of the sheet forming die; as Figure 5 shown, through the electric heating heat source 7 and the plurality of temperature sensors, a plurality of regions are obtained, and each region has a temperature sensor socket 8, so that the temperatures of region 5-1 and region 5-5 are set higher than the central region 5-3, and the temperatures of the sub-central regions 5-2 and 5-4 are in the middle. The die has the function of zonal heating, further solving the problem that the fluidity of the UHMW-PE melt in the flow channel is affected by uneven temperature. In this embodiment, the temperatures of region 5-1 and region 5-5 are 180 °C, the temperatures of sub-central regions 5-2 and 5-4 are 170 °C, and the temperature of the central region 5-3 is 160 °C.

[0137] The distance between the die orifice of the sheet forming die and the three-roll calendering equipment is 50-100 mm;

[0138] Using the extrusion and plasticizing forming system of this embodiment, ultra-high molecular weight polyethylene resin sheets can be produced. The raw material of the sheets is ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 1.78 million;

[0139] The viscosity-average molecular weight of the sheet is 1.65 million, that is, the reduction of the viscosity-average molecular weight of the sheet relative to the ultra-high molecular weight polyethylene resin of 1.78 million is 7.3%, not less than 90% of the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin, that is, the retention rate of the viscosity-average molecular weight of the sheet is more than 90%; the thickness of the sheet is 0.3 mm.

[0140] The preparation method of the sheet includes: feeding the raw materials of the sheet into the twin-screw eccentric rotor extrusion and plasticizing subsystem from the feeding section, after extrusion and plasticization by the first rotor combination section with gradually decreasing pitch and the straight extrusion and strengthening section, material reflux is generated by the reflux section to strengthen extrusion, plasticization and compaction; finally, after the uniformity of melt temperature, pressure and plasticization degree is achieved by the melt conveying section, it is fed into the sheet forming die; the melt coming out of the die lip of the sheet forming die is subjected to three-roll calendering and winding treatment to obtain the sheet (UHMW-PE).

[0141] The head temperature of the twin-screw eccentric rotor extrusion and plasticizing subsystem is 180 °C, and the temperature of each section is 180 - 190 °C;

[0142] The extrusion amount of the twin-screw eccentric rotor extrusion and plasticizing subsystem is 3.5 kg / min;

[0143] The rotational speed of the eccentric rotor of the twin-screw eccentric rotor extrusion and plasticizing subsystem is 180 - 220 revolutions per minute;

[0144] The temperature of the three-roll calendering equipment is 90 °C.

[0145] Examples 2 - 3

[0146] Examples 2 - 3 respectively provide an ultra-high molecular weight polyethylene resin sheet, both of which are prepared by using the extrusion and plasticizing molding system of Example 1. The differences between Examples 2 - 3 and Example 1 are as follows:

[0147] The thickness of the sheet in Example 2 is 0.5 mm.

[0148] The thickness of the sheet in Example 3 is 1.0 mm.

[0149] Example 4

[0150] This example provides a self-adhesive ultra-high molecular weight polyethylene waterproof coiled material, which includes an ultra-high molecular weight polyethylene resin sheet (Example 1), an upper self-adhesive layer (1.0 mm self-adhesive butyl rubber) and a release film arranged in sequence from top to bottom.

[0151] Example 5

[0152] This embodiment provides a pre-laid and self-adhesive ultra-high molecular weight waterproof coiled material, which includes a lower self-adhesive layer (0.3 mm self-adhesive butyl rubber), an ultra-high molecular weight polyethylene resin sheet (Example 2), a styrene-butene block copolymer type polymer hot melt pressure-sensitive adhesive layer, and a weather-resistant polyacrylate type anti-sticking coating arranged in sequence from top to bottom.

[0153] The total thickness of the styrene-butene block copolymer type polymer hot melt pressure-sensitive adhesive layer and the weather-resistant polyacrylate type anti-sticking coating is 0.3 mm;

[0154] Comparative Example 1

[0155] This comparative example provides a high-density polyethylene HDPE waterproof board, which is made by single-screw extrusion of Sinopec HDPE 5000S resin.

[0156] Comparative Example 2

[0157] In this comparative example, an ultra-high molecular weight polyethylene resin with a viscosity-average molecular weight of 1.8 million was processed using a disk-shaped force chemical reactor with high shear force. As the number of grinding times increased, its melt flow index gradually increased. After 30 times of grinding, the melt flow index increased from the initial 0 to 0.101 g / 10 min, and the viscosity-average molecular weight decreased by 46%. (Zou Huawei. Research on the Influence of Stress-Induced Reaction on the Rheological Behavior and Properties of Polymers. Sichuan: Sichuan University, 2005)

[0158] Test Example 1

[0159] In this test example, the physical properties of the sheets of Examples 1-3 and Comparative Example 1 were tested, and the results are shown in Table 3. Among them:

[0160] The test methods for tensile strength, elongation at break, and right-angle tear refer to

[0161] GB / T18173.1-2013 JS2 resin type sheet.

[0162] The test method for puncture resistance refers to GB / T 23457-2017 pre-laid waterproof coiled material.

[0163] The test method for wear resistance refers to GB / T1768-2006, rubber grinding wheel model CS-17, load 750 g, 500 revolutions.

[0164] Table 3

[0165]

[0166]

[0167] Test Example 2

[0168] This test example conducts physical property data tests on the self-adhesive ultra-high molecular weight polyethylene waterproof coiled material of Example 4. The results are shown in Table 4 below. The tests are based on GB / T 328.21-2007 Polymer waterproofing membranes - Seam shear properties and the test method for the adhesion of the coiled material to the aluminum plate in GB 23441-2009, item 5.12.2.

[0169] Table 4 Adhesion properties of self-adhesive ultra-high molecular weight polyethylene waterproof coiled material (N / mm)

[0170] Coil and coil Coil and aluminum plate Coil and cement board 2.3 2.7 3.6

[0171] Test Example 3

[0172] This test example conducts physical property data tests on the pre-laid and self-adhered ultra-high molecular weight waterproof coiled material of Example 5. The results are shown in Table 5 below. The tests are based on GB / T 23457-2007.

[0173] Table 5 Adhesion properties of pre-laid and self-adhered ultra-high molecular weight waterproof coiled material to the cast-in-place concrete (N / mm)

[0174] No treatment Heat treatment UV treatment Immersed in water for 28 days 3.3 2.7 3.6 3.8

[0175] The retention rate of the viscosity-average molecular weight is of great significance for ensuring the properties of the sheet. The excellent properties of ultra-high molecular weight polyethylene resin are due to the entanglement of ultra-long molecular chains, which endows the sheet with excellent impact resistance, high temperature resistance, low temperature resistance, and wear resistance.

[0176] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An extrusion plasticizing and forming system, characterized in that, The system for extrusion and plasticizing molding includes a barrel, a twin-shaft eccentric rotor extrusion and plasticizing subsystem, a sheet forming die, a three-roll calendering device, and a sheet winding device; The twin-shaft eccentric rotor extrusion and plasticizing subsystem includes two meshing eccentric rotors and a stator. The eccentric rotor includes a plurality of eccentric spiral structures and eccentric cylindrical structures, and includes a feeding section, a melting and plasticizing section, and a melt conveying section connected in sequence from the feeding end to the discharging end; The feeding section includes a non-eccentric threaded rotor; The melting and plasticizing section includes a first rotor combination section with gradually decreasing pitch, a straight extrusion strengthening section, and a reflux section connected in sequence; The melt conveying section includes a first melt conveying section, a second melt conveying section, and a second rotor combination section with gradually decreasing pitch connected in sequence; The spiral direction of the reflux section is opposite to that of other sections of the eccentric rotor.

2. The extrusion plasticizing and forming system according to claim 1, characterized in that, The diameter of the eccentric rotor is 20 - 120 mm.

3. The extrusion plasticizing and forming system according to claim 1, wherein The compression ratio of the eccentric rotor is 2 - 2.8:

1.

4. The extrusion plasticizing and forming system according to claim 1, wherein The length-diameter ratio of the eccentric rotor is 38 - 45:

1.

5. The extrusion plasticizing and forming system according to claim 1, wherein, The melting and plasticizing section is in multiple segments, and the number of segments, length, and rotor combination length-diameter ratio are determined according to the viscosity-average molecular weight of the resin to be extruded and plasticized.

6. The extrusion plasticizing and forming system according to claim 1, characterized in that, The melt conveying section is in multiple segments, and the number of segments, length, and rotor combination length-diameter ratio are determined according to the viscosity-average molecular weight of the resin to be extruded and plasticized.

7. The extrusion plasticizing and forming system according to claim 1, wherein, The eccentric rotor contains pins.

8. The extrusion plasticizing and forming system according to claim 1, wherein, The die lip of the sheet forming die is a flat-mouth structure die lip, and the thickness perpendicular to the sheet extrusion direction of the flat-mouth structure die lip is 2 - 20 cm.

9. The extrusion plasticizing and forming system according to claim 8, wherein, An electric heating heat source and a plurality of temperature sensors are arranged on the sheet forming die. The plurality of temperature sensors are arranged along the direction parallel to the die lip. The electric heating heat source is connected to the plurality of temperature sensors for realizing zonal heating in the runner of the sheet forming die.

10. The extrusion plasticizing and forming system according to claim 8, characterized in that, The distance between the die orifice of the sheet forming die and the three-roll calendering device is 5 - 300 mm.

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