Double-screw extruder

Abstract

The utility model relates to the technical field of extrusion machinery, in particular to a double-screw extruder. The double-screw extruder provided by the utility model comprises an optimized barrel configuration and an optimized screw group, the optimized barrel configuration comprises 14 sections of barrels and is provided with a feed opening, a front exhaust opening, two water injection openings and three vacuum exhaust openings, the optimized screw group is provided with a thin shearing block at a screw plasticizing section, a large-lead shearing block is replaced, the shearing heat is reduced, and the shearing efficiency is improved. A TME threaded block is arranged behind a first water injection port of the mixing section, an LSK stretching block and an SME threaded block are arranged behind a second water injection port of the mixing section, a strong mixing screw element can improve the solubility of water vapor and VOC substances, a 2D ultra-large lead conveying block is arranged on the exhaust section, the devolatilization effect is improved, small molecular substances in melt are reduced, the smell of finished product particles is comprehensively improved, and the product quality is improved. The low-odor polypropylene material is applied to processing and production of automotive interiors, and the effects of slowing down the air pollution speed in an automobile and improving the driving experience can be achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to extrusion machinery technical field, especially a double screw extruder. BACKGROUND

[0002] Most of the automotive interior parts use polypropylene materials, and the ordinary modified polypropylene smells pungent, and volatile organic compounds such as toluene, butyl acetate and dichlorobenzene are easily produced in the use process, which pollutes the air in the car and easily has a great impact on health for a long time driving. With the development of automobile manufacturing industry, the vehicle enterprises continuously improve the odor requirements of automotive interior products, and the odor of the material produced by the existing single water injection and double vacuum process cannot meet the standards of some high requirement automotive interior manufacturers, and how to produce low odor grade automotive interior materials is a technical problem to be solved in the current field. SUMMARY

[0003] To solve the technical problem of how to produce low odor grade automotive interior materials, the utility model provides a double screw extruder, which comprises an optimized barrel configuration and an optimized screw group.

[0004] The optimized barrel configuration has a total of 14 barrels, and the upper part of part of the barrels is provided with an opening, and the opening comprises a feeding port, a front exhaust port, a first water injection port, a second water injection port, a first vacuum exhaust port, a second vacuum exhaust port and a third vacuum exhaust port.

[0005] The optimized screw group comprises a thin shear block, a TME thread block, an LSK stretching block, an SME thread block and a 2D super-large lead conveying block sleeved on the screw.

[0006] The barrel provided with the feeding port is used as the first barrel of the optimized barrel configuration, and the number of barrel nodes is calculated in the conveying direction of the material along the screw.

[0007] In an embodiment, the front exhaust port is arranged at the fourth barrel.

[0008] In an embodiment, the first water injection port is arranged at the fifth barrel, and the second water injection port is arranged at the ninth barrel.

[0009] In an embodiment, the first vacuum exhaust port is arranged at the seventh barrel, the second vacuum exhaust port is arranged at the eleventh barrel, and the third vacuum exhaust port is arranged at the thirteenth barrel.

[0010] In an embodiment, the thin shear block is arranged in the plasticizing section.

[0011] In an embodiment, the TME thread block, the LSK stretching block and the SME thread block are arranged in the mixing section.

[0012] Further, the TME thread block is arranged after the first water injection port.

[0013] Further, the LSK stretching block and the SME thread block are arranged after the second water injection port.

[0014] In an embodiment, the 2D super large lead conveying block is arranged in the exhaust section.

[0015] Further, the exhaust section comprises a natural exhaust section and a vacuum exhaust section.

[0016] The double screw extruder provided by the utility model has the advantages that the barrel configuration and screw group are optimized, a plurality of openings are arranged on the upper part of part of the barrels, a front exhaust port is arranged at the fourth barrel, a first water injection port is arranged at the fifth barrel, a second water injection port is arranged at the ninth barrel, a first vacuum exhaust port is arranged at the seventh barrel, a second vacuum exhaust port is arranged at the eleventh barrel, and a third vacuum exhaust port is arranged at the thirteenth barrel, in addition, a thin shear block is arranged in the plasticizing section, so that the shearing heat is reduced, a TME thread block is arranged after the first water injection port in the mixing section, an LSK stretching block and an SME thread block are arranged after the second water injection port, so that the melt and water vapor are fully mixed and uniformly mixed, the contact area of the melt and water vapor is increased, the solubility of water vapor and VOC substances is improved, a 2D super large lead conveying block is arranged in the exhaust section, the devolatilization effect is improved, the small molecular substances in the melt are reduced, and the odor of the finished product particles is comprehensively improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0018] Figure 1 The double screw extruder barrel configuration and optimized screw group schematic diagram provided by the embodiment 1 of the utility model are shown in the figure.

[0019] Figure 2 The double screw extruder barrel configuration and non-optimized screw group schematic diagram provided by the comparative example 1 of the utility model are shown in the figure.

[0020] Figure 3 The double screw extruder double water injection three vacuum barrel configuration and non-optimized screw group schematic diagram provided by the comparative example 2 of the utility model are shown in the figure.

[0021] Figure 4 The double screw extruder single water injection three vacuum barrel configuration and non-optimized screw group schematic diagram provided by the comparative example 3 of the utility model are shown in the figure.

[0022] Reference signs:

[0023] 100 - barrel; 110 - feed opening; 120 - front vent; 121 - vent; 130 - first water injection port; 131 - second water injection port; 140 - first vacuum vent; 141 - second vacuum vent; 142 - third vacuum vent; 200 - screw; 210 - thin shear block; 220 - TME thread block; 230 - LSK stretch block; 240 - SME thread block; 250 - 2D super large lead conveying block. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0026] Embodiment 1

[0027] The present embodiment provides a twin-screw extruder, which comprises an optimized barrel configuration and an optimized screw set as shown in Figure 1

[0028] The optimized barrel configuration comprises a total of 14 barrels 100, and some of the barrels 100 are provided with openings in the upper part, the openings comprising a feed opening 110, a front vent 120, a first water injection port 130, a second water injection port 131, a first vacuum vent 140, a second vacuum vent 141 and a third vacuum vent 142;

[0029] The optimized screw set comprises a thin shear block 210, a TME thread block 220, an LSK stretch block 230, an SME thread block 240 and a 2D super large lead conveying block 250 sleeved on the screw 200;

[0030] ​The cylinder body 100 provided with the discharge port 110 is taken as the first section of the cylinder body in the optimized cylinder body arrangement.

[0031] In particular, the front exhaust port 120 is arranged at the fourth section of the cylinder body.

[0032] In particular, the first water injection port 130 is arranged at the fifth section of the cylinder body, and the second water injection port 131 is arranged at the ninth section of the cylinder body.

[0033] In particular, the first vacuum exhaust port 140 is arranged at the seventh section of the cylinder body, the second vacuum exhaust port 141 is arranged at the eleventh section of the cylinder body, and the third vacuum exhaust port 142 is arranged at the thirteenth section of the cylinder body.

[0034] In particular, the thin shear block 210 is arranged at the plasticizing section.

[0035] In particular, the thin shear block 210 is arranged at the plasticizing section.

[0036] In particular, the TME thread block 220, the LSK stretching block 230, and the SME thread block 240 are arranged at the mixing section.

[0037] In this embodiment, further, the TME thread block 220 is arranged after the first water injection port 130; in particular, the TME thread block 220 helps to fully mix the material, the two screws 200 are closely meshed and rotated, and the material is effectively mixed in the C-shaped chamber, thereby improving the uniformity of the melt.

[0038] The LSK stretching block 230 and the SME thread block 240 are arranged after the second water injection port; in particular, the LSK stretching block 230 generates complex material flow through forward and reverse screw combination and large lead, improves the distribution mixing capacity, and reduces the melt temperature; in addition, the material across the screw ridge is stretched in the wedge-shaped area, which is beneficial to better breaking and melting of the melt.

[0039] The SME thread block 240 is a small lead thread block obtained by grooving a small lead conveying block, has high fullness and certain conveying capacity, can generate high flow and high dispersion effect, and has low shear heat.

[0040] In particular, the 2D super large lead conveying block 250 is arranged at the exhaust section.

[0041] In particular, the 2D super large lead conveying block 250 can improve the devolatilization effect, reduce small molecular substances in the melt, and improve the odor of the finished product.

[0042] Further in the embodiment, the exhaust section comprises a natural exhaust section and a vacuum exhaust section.

[0043] Preferably in the embodiment, the twin-screw extruder is RXT-65 from Nanjing Ruia, with a length-diameter ratio of 56:1, a barrel temperature of 180-200℃, a main motor speed of 500 rpm, and a production capacity of 400 kg / h.

[0044] Preferably in the embodiment, the TME thread block 220 is TME C12-3-48, the LSK stretching block 230 is LSK128 and LSK128L, and the SME thread block 240 is SME32 / 32.

[0045] In the embodiment, the specifications of the thread elements used are shown in Table 1:

[0046] Table 1 Specifications of thread elements

[0047]

[0048] In the embodiment, the complete arrangement of the optimized screw group is shown in Table 2:

[0049] Table 2 Complete arrangement of optimized screw group

[0050]

[0051] The embodiment provides a twin-screw extruder with an optimized barrel configuration and an optimized screw group, wherein the optimized barrel configuration has 1 front exhaust port, 2 water injection ports, and 3 vacuum exhaust ports, and the optimized screw group uses thin shear blocks to reduce excessive concentrated shear heat generated during plasticization, reduces the generation of small molecular substances, uses strong mixing screw elements TME thread blocks, LSK stretching blocks, and SME thread blocks after water injection to fully mix and blend the melt and water vapor, increases the contact area of the melt and water vapor, improves the solubility of water vapor and VOC substances, in addition, 2D large lead conveying blocks are used in the natural exhaust section and the vacuum exhaust section to improve the devolatilization effect and reduce small molecular substances in the melt, thereby comprehensively improving the odor of the finished product.

[0052] Comparative Example 1

[0053] The comparative example provides a twin-screw extruder, which is different from the embodiment 1 of the utility model in that, as shown in Figure 2 , an optimized screw group is not used.

[0054] Comparative Example 2

[0055] The comparative example provides a twin-screw extruder, which is different from the embodiment 1 of the utility model in that, as shown in Figure 3As shown, a double-water-injection three-vacuum-cylinder configuration is adopted, and the upper part of part of the cylinder 100 is provided with openings, the openings including a discharging port 110, a first water injection port 130, a second water injection port 131, a first vacuum exhaust port 140, a second vacuum exhaust port 141, and a third vacuum exhaust port 142, and an optimized screw group is not used.

[0056] In the present comparative example, the cylinder 100 provided with the discharging port 110 is taken as the first section cylinder of the optimized cylinder configuration, and the number of cylinder sections is calculated in the conveying direction of the screw 200.

[0057] In the present comparative example, the first water injection port 130 is arranged at the fifth section cylinder, and the second water injection port 131 is arranged at the ninth section cylinder.

[0058] In the present comparative example, the first vacuum exhaust port 140 is arranged at the seventh section cylinder, the second vacuum exhaust port 141 is arranged at the eleventh section cylinder, and the third vacuum exhaust port 142 is arranged at the thirteenth section cylinder.

[0059] Comparative Example 3

[0060] The present comparative example provides a double-screw extruder, which is different from the double-screw extruder of the first embodiment of the present application in that the length-diameter ratio of the machine table is 52:1, as shown in Figure 4 As shown, a single-water-injection double-vacuum-cylinder configuration is adopted, and there are a total of 13 cylinders 100, and the upper part of part of the cylinder 100 is provided with openings, the openings including a discharging port 110, an exhaust port 121, a first water injection port 130, a first vacuum exhaust port 140, and a second vacuum exhaust port 141, and an optimized screw group is not used.

[0061] In the present comparative example, the exhaust port 121 is arranged at the fifth section cylinder.

[0062] In the present comparative example, the first water injection port 130 is arranged at the tenth section cylinder.

[0063] In the present comparative example, the first vacuum exhaust port 140 is arranged at the eighth section cylinder, and the second vacuum exhaust port 141 is arranged at the twelfth section cylinder.

[0064] The complete screw group arrangement of the double-screw extruders provided in Comparative Examples 1-3 is shown in Table 3:

[0065] Table 3 Complete screw group arrangement of double-screw extruders of Comparative Examples 1-3

[0066]

[0067] Test Example

[0068] Weigh out each component of the polypropylene material according to the mass percentage, and weigh out a total of 4 groups. Stir each group at 300 rpm for 120 s to obtain a premix. Feed the premix into a loss-in-weight feeder and melt mix, extrude and granulate the premix using the twin-screw extruders provided in Example 1 and Comparative Examples 1-3. Then place the granules in an online drying tank and dry them at 120°C for 8 hours. Perform performance tests on the granule products.

[0069] The raw material formulation for polypropylene is shown in Table 4, and the process parameters for the twin-screw extruder and injection molding machine are shown in Table 5.

[0070] Table 4 Raw material formulation for polypropylene materials

[0071]

[0072] Table 5 Process parameters for twin-screw extruders and injection molding machines

[0073]

[0074] In the experimental examples provided by this utility model, preferably, the amounts of each raw material component of the polypropylene material are as follows: 50% PP particles 1, 27% PP particles 2, 1% black masterbatch, 21% talc, 0.3% antioxidant, 0.3% lubricant and 0.4% UV stabilizer.

[0075] In the experimental examples provided by this utility model, preferably, the raw materials are weighed using an electronic analytical balance BSA224S-CW, mixed using a high-speed mixer SHR200, fed using a loss-in-weight feeder K2-ML-D5-S60, granulated using a plastic pelletizer (70-120A) for hard plastics, and dried using a blower dryer DHG-9245A.

[0076] The test materials were subjected to physical property testing and odor grade evaluation. The density property testing was performed according to ISO 1183-1 Plastics - Determination of density of non-foamed plastics, the ash content property testing was performed according to ISO 3451-1 Plastics - Determination of ash content, the melt flow rate property testing was performed according to ISO 1133 Plastics - Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) for thermoplastics - Part 1: Melt mass-flow rate (MFR), the tensile strength property testing was performed according to ISO 527-2 Plastics - Determination of tensile properties - Part 2: Test conditions, the bending strength and bending modulus property testing was performed according to ISO 178 Plastics - Determination of Charpy notched impact strength was performed according to ISO 180 Plastics - Determination of Charpy notched impact strength, and the odor grade testing was performed according to FLTM BO131 Ford odor test standard. The odor grade evaluation scale is shown in Table 6, the physical property testing results are shown in Table 7, and the odor grade evaluation results are shown in Table 8:

[0077] Table 6 Odor grade evaluation scale

[0078]

[0079] Table 7 Physical property testing results

[0080]

[0081] Table 8 Odor grade evaluation results

[0082]

[0083] In addition, the appearance of the test materials was compared. The particle appearance of the test materials of Example 1 and Comparative Examples 1-3 was normal.

[0084] According to the above test results, the particle appearance of the test materials of Example 1 and Comparative Examples 1-3 was normal, and the physical property data were qualified. However, the odor evaluation grade of the test materials of Comparative Examples 1-3 was still high, and the average odor grade was more than 2.5, which could be obviously felt. The odor evaluation grade of the test material of Example 1 was better, which was less than 2.5, and could be felt, but did not disturb people. Therefore, the use of the twin-screw extruder configured with the optimized barrel configuration and the optimized screw group for producing the polypropylene material can significantly reduce the pungent odor of the polypropylene material, and can slow down the speed of air pollution in the car and improve the driving experience when used for the processing and production of automotive interiors.

[0085] Although the terms such as optimizing barrel configuration, optimizing screw set, front rower port, water injection port, vacuum exhaust port, thin shear block, TME thread block, LSK stretch block, SME thread block, 2D super large lead conveying block, C-shaped cell, melt, melting, dispersion, shear, devolatilization, granulation, etc. are used more in this paper, the possibility of using other terms is not excluded. The use of these terms is only to facilitate the description and explanation of the essence of the utility model; any additional limitation by interpreting them is contrary to the spirit of the utility model.

[0086] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, but not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A twin-screw extruder, characterized by: The optimization barrel configuration and the optimization screw group are included; The optimization barrel configuration includes 14 barrels (100) in total, and some barrels (100) are provided with openings in the upper part, including a feeding port (110), a front exhaust port (120), a first water injection port (130), a second water injection port (131), a first vacuum exhaust port (140), a second vacuum exhaust port (141), and a third vacuum exhaust port (142); The optimization screw group includes a thin shear block (210), a TME thread block (220), an LSK stretching block (230), an SME thread block (240), and a 2D super-large lead conveying block (250) sleeved on a screw rod (200); The barrel (100) provided with the feeding port (110) is taken as the first barrel of the optimization barrel configuration, and the number of barrel sections is calculated in the conveying direction of the material along the screw rod (200).

2. Twin screw extruder according to claim 1, characterized in that The front exhaust port (120) is arranged at the fourth barrel.

3. The twin-screw extruder of claim 1, wherein: The first water injection port (130) is arranged at the fifth barrel, and the second water injection port (131) is arranged at the ninth barrel.

4. The twin-screw extruder of claim 1, wherein: The first vacuum exhaust port (140) is arranged at the seventh barrel, the second vacuum exhaust port (141) is arranged at the eleventh barrel, and the third vacuum exhaust port (142) is arranged at the thirteenth barrel.

5. The twin-screw extruder of claim 1, wherein: The thin shear block (210) is arranged in the plasticizing section.

6. The twin screw extruder of claim 1, wherein: The TME thread block (220), the LSK stretching block (230), and the SME thread block (240) are arranged in the mixing section.

7. Twin screw extruder according to claim 6, characterized in that The TME thread block (220) is arranged after the first water injection port.

8. The twin-screw extruder of claim 6, wherein: The LSK stretching block (230) and the SME thread block (240) are arranged after the second water injection port.

9. The twin screw extruder of claim 1, wherein: The 2D super-large lead conveying block (250) is arranged in the exhaust section.

10. Twin screw extruder according to claim 9, characterized in that The exhaust section includes a natural exhaust section and a vacuum exhaust section.

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