Fast-extrusion, anti-sagging and large-diameter pipeline material and preparation method thereof

Abstract

The invention discloses a fast-extrusion, anti-sagging and large-diameter pipeline material and a preparation method thereof. The anti-sagging large-diameter pipeline material comprises the following components: high-density polyethylene, functionalized polyethylene, a cycloolefin polymer and carbon black master batch. Wherein the functionalized polyethylene is maleic anhydride grafted polyethylene resin grafted modified graphene. Due to the special structure of the functional master batch, on one hand, the functional master batch has very good compatibility with a high-density polyethylene matrix, uniform dispersion can be realized, so that a very good enhancement characteristic is provided, and meanwhile, functional polyethylene has an extremely high heat conductivity coefficient, and has a better sag resistance characteristic when a large-caliber thick-wall pipe (the pipe diameter is more than 1000mm and the wall thickness is more than 100mm) is produced. According to the large-diameter pipeline material disclosed by the invention, a thinner large-diameter pipe with more uniform wall thickness can be produced through the comprehensive influence of high heat dissipation efficiency of the polyethylene master batch in the formula, rapid cooling and shaping after extrusion of cycloolefin and the like.

Description

Technical Field

[0001] The present invention relates to a large-diameter anti-sag pipeline material for municipal engineering and nuclear power industry, and in particular to a large-diameter pipeline material with fast extrusion and anti-sag properties and a preparation method thereof, belonging to the technical field of high-end anti-sag pipeline materials. Background Art

[0002] Large-diameter polyethylene (PE) pipes usually refer to solid-wall pipes with an outer diameter (DN) greater than 800mm. In recent years, due to the excellent comprehensive performance of PE pipes, such as corrosion resistance, good flexibility and good welding performance, large-diameter PE pipes have been used in domestic water supply, nuclear power plant cooling systems, marine aquaculture, seawater desalination projects, submarine waste and sewage discharge, transportation of corrosive media or slurry, corrosive soil environments, and lining method for repairing old pipes.

[0003] In the process of large-diameter pipe extrusion, due to the thick pipe wall, the cooling and solidification speed is slow, the production efficiency is extremely low, and the melt will sag under the action of gravity, resulting in a small wall thickness on the top and a large wall thickness on the bottom, that is, the "melt sag effect", which makes the pipe wall fail to meet the required tolerance and cannot achieve the required butt fusion welding. To improve these problems, on the one hand, the molecular design of the resin is needed, and at the same time, the equipment needs to be upgraded. Both material development and equipment modification are huge challenges, so it is of great significance to study a fast-extruded, anti-sag large-diameter pipe material.

[0004] Chinese patent CN 114426718 A provides a polyethylene resin with anti-sag performance and its preparation and application. The main method is to broaden the molecular weight distribution to 8-20 and increase the molecular weight (weight average molecular weight Mw is 200,000-240,000) through the polymerization stage. The advantage of this method is that the polymerized product has good stability, but there is no long chain branching in the structure, and the molecular weight distribution is not substantially different from the general HDPE pipe material, and the improvement of anti-sag performance is limited.

[0005] Chinese patent CN113930008A provides a polymerization production method for anti-sag pipe materials, using a highly active Ziegler-Natta catalyst, the Innovene S process double-loop high-density polyethylene device process, and a melt strength ≥ 0.35N (230°C). The advantage of this method is that the polymerization is controllable, and the double-loop process is used to broaden the molecular weight distribution, increase the proportion of molecular weights above 1 million, and improve the molecular entanglement performance to achieve anti-sag characteristics, but its super-large molecular weight proportion is still low, the molecular entanglement ability is weak, and the extrusion efficiency cannot be improved, and it still cannot meet the downstream processing and use requirements.

[0006] In general, the sag effect is still quite obvious during the production of the anti-sag large-diameter pipe materials (pipe diameter over 1000mm, wall thickness over 100mm) currently on the market, and it is impossible to reduce the wall thickness within the standard range. At the same time, the processing efficiency is low and the production cost is high. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a fast extrusion, anti-sag, large-caliber pipe material and a preparation method thereof, so as to solve the problems of obvious sag effect and low extrusion efficiency of existing pipe materials. The present invention optimizes the formula, and after the pipe is extruded, it can quickly dissipate heat and accelerate the cooling and characterization of the matrix. In addition, the formula contains cycloolefin copolymer, which, due to its special amorphous non-crystalline structure, can be quickly characterized after melt extrusion, and can cover the high-density polyethylene matrix with sag effect. The present invention can significantly reduce the sag effect, so that the large-caliber thick-wall pipe extrusion process can have a more uniform pipe wall and higher extrusion efficiency.

[0008] In order to achieve the above invention object, the technical solution adopted by the present invention is as follows:

[0009] A fast extrusion, anti-sag, large-diameter pipe material, comprising the following components in parts by weight:

[0010] 75-95 parts of high-density polyethylene, preferably 80-90 parts;

[0011] 2-10 parts of functionalized polyethylene, preferably 4-8 parts;

[0012] 2-8 parts of cycloolefin polymer, preferably 3-7 parts;

[0013] Carbon black masterbatch 1-7 parts, preferably 2-6 parts.

[0014] The fast extrusion, anti-sag, large-diameter pipe material of the present invention, wherein the high-density polyethylene has a melt index of 0.15-0.25 g / 10 min under 190° C. and 5 kg test conditions, and a density of 0.945-0.955 g / cm 3 .

[0015] The fast extrusion, anti-sag, large-diameter pipeline material described in the present invention, wherein the functionalized polyethylene is obtained by reacting maleic anhydride grafted polyethylene (maleic anhydride grafting rate 0.5-2.0%) and graphene oxide (particle size 0.1-30um) as main raw materials, for example: graphene oxide and maleic anhydride grafted polyethylene are put into an internal mixer, at 190-220°C, a speed of 500-1500r / min, and a reaction time of 10-30min, so that the active hydroxyl groups on the surface of graphene oxide react with maleic anhydride, and finally vacuum (vacuum degree 0.2-0.8MPa), and strand granulation is performed to obtain graphene oxide modified functionalized polyethylene. In terms of molecular structure, it has both long-chain polyethylene and graphene oxide with excellent thermal conductivity. The former provides compatibility with high-density polyethylene substrate, and the latter can conduct heat better after the pipe is extruded, which speeds up the cooling of the pipe and reduces the sag effect, so the wall thickness of large-diameter thick-walled pipes is more uniform.

[0016] As a specific embodiment, the method for preparing functionalized polyethylene includes:

[0017] 50-80 parts of maleic anhydride grafted polyethylene and 20-50 parts of graphene oxide are placed in an internal mixer, at 190-220° C., a rotation speed of 500-1500 r / min, and a reaction time of 10-30 min. The obtained premix is ​​passed through a flat vulcanizer, molded into 0.5-2.0 mm thin sheets at 190-220° C., cut into pieces, and then the premix is ​​melt-mixed through a single screw extruder (five-zone temperature range of 180° C. / 195° C. / 195° C. / 190° C. / 180° C.), and finally vacuumed (vacuum degree 0.2-0.8 MPa) to prepare functionalized polyethylene.

[0018] The fast extrusion, anti-sag, large-diameter pipe material of the present invention, wherein the cycloolefin polymer is a copolymer of ethylene and cycloolefin, and has a melt index of 20-70 g / 10 min under the test conditions of 280° C. and 2.16 kg.

[0019] The fast extrusion, anti-sag, large-diameter pipeline material of the present invention, wherein the carbon black masterbatch is a commercially available carbon black masterbatch with a polyethylene carrier, and the carbon black content is 38-42%.

[0020] The method for preparing the fast extrusion, anti-sag, large-diameter pipeline material of the present invention comprises the following steps:

[0021] (1) Preparation of functionalized polyethylene;

[0022] (2) Preparation of anti-sag pipe: High-density polyethylene, functional polyethylene, cycloolefin polymer, and carbon black masterbatch are weighed in proportion, added to a high-speed mixer (speed 1000-2000 r / min, temperature room temperature, time 3-10 min) for uniform mixing, and fed to a single-screw extruder feeder. The extrusion process temperature is maintained at 200°C ± 15°C, and the feed is extruded, cooled, pulled, and cut smoothly.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Traditional anti-sag pipe materials are mainly achieved by regulating the molecular structure in the polymerization stage and blending ultra-high molecular weight polyethylene and other materials in the post-processing stage. The polymerization stage is mainly to adjust the molecular weight distribution, increase the molecular weight content above 1 million as much as possible, improve the entanglement effect of macromolecules, and thus improve the anti-sag performance in the extrusion process. However, the entanglement effect of polymerized macromolecules is limited, and the gap is large compared with the long-chain branched structure, and the anti-sag performance cannot be significantly improved; another method is to physically blend ultra-high molecular weight polyethylene, which also has a general effect and is prone to pitting, affecting the appearance of the product and even causing failure of the hydrostatic test;

[0025] The physical blending method of the present invention is simple and quick, and under the comprehensive influence of the functionalized polyethylene and the cycloolefin copolymer, the anti-sag performance is greatly improved, and the extrusion processing efficiency is also significantly improved. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with examples. The following examples are only used as illustrations of the present invention and are not intended to limit the scope of protection of the present invention.

[0027] Performance evaluation method:

[0028] High temperature sag test method: Place the 10mm*10mm*2mm thin sheet prepared in each example and comparative example flat on the iron stand in the oven at 200°C, and observe the sag height of the sample after standing for 30 minutes. The result is less than 5cm, which means that the requirements of fast extrusion and low sag are met, and large-diameter pipe materials can be produced.

[0029] Tube wall appearance: The tube wall is extruded smoothly, with no obvious pitting visible to the naked eye.

[0030] Hydrostatic test: extrude DN63*5.8 pipes, refer to the national standard GB / T13663.2, conduct a hydrostatic strength test at 20℃ for 100h, and the pipes are qualified if there is no bursting.

[0031] Example 1

[0032] 1) Preparation of functionalized polyethylene: 50 parts of maleic anhydride grafted polyethylene (Jiayirong CMG5804) and 50 parts of graphene oxide (Xianfeng Nano, thickness <5 nm, sheet diameter 20 um) were placed in a high-speed stirring mixer at 210°C, a rotation speed of 800 r / min, and a reaction time of 20 min. The obtained premix was molded into 2.0 mm thin sheets at 210°C in a flat vulcanizer, cut into pieces, and then the premix was melt-mixed in a single screw extruder (five-zone temperature range 180°C / 195°C / 195°C / 190°C / 180°C) to prepare functionalized polyethylene;

[0033] 2) Preparation of anti-sag pipe: Weigh 80 parts of high-density polyethylene (Wanhua 23050), 8 parts of functionalized polyethylene, 7 parts of cycloolefin (Japan Zeon K26R), and 5 parts of carbon black masterbatch (Beihua High-tech PECB4025A), add them to a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them to the discharge scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and discharge the materials smoothly for extrusion, cooling, pulling, and cutting.

[0034] Example 2

[0035] 1) Preparation of functionalized polyethylene: 80 parts of maleic anhydride grafted polyethylene (Jiayirong CMG5804) and 20 parts of graphene oxide (Xianfeng Nano, thickness <5 nm, sheet diameter 20 um) were placed in a high-speed stirring mixer at 210°C, a rotation speed of 800 r / min, and a reaction time of 20 min. The obtained premix was passed through a flat vulcanizer and molded into 2.0 mm thin sheets at 210°C, cut into pieces, and then the premix was melt-mixed through a single screw extruder (five-zone temperature range 180°C / 195°C / 195°C / 190°C / 180°C) to prepare functionalized polyethylene;

[0036] 2) Preparation of anti-sag pipe: Weigh 88 parts of high-density polyethylene (Wanhua 23050), 4 parts of functionalized polyethylene, 3 parts of cycloolefin (Japan Zeon K26R), and 5 parts of carbon black masterbatch (Beihua High-tech PECB4025A), add them into a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them into the feeding scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and extrude, cool, pull and cut the materials smoothly.

[0037] Example 3

[0038] 1) Preparation of functionalized polyethylene: 70 parts of maleic anhydride grafted polyethylene (Jiayirong CMG5804) and 30 parts of graphene oxide (Xianfeng Nano, thickness <5 nm, sheet diameter 20 um) were placed in a high-speed stirring mixer at 200°C, a rotation speed of 800 r / min, and a reaction time of 20 min. The obtained premix was passed through a flat vulcanizer and molded into 1.0 mm thin sheets at 210°C, cut into pieces, and then the premix was melt-mixed through a single screw extruder (five-zone temperature range 180°C / 195°C / 195°C / 190°C / 180°C) to prepare functionalized polyethylene;

[0039] 2) Preparation of anti-sag pipe: Weigh 83 parts of high-density polyethylene (Wanhua 23050), 4 parts of functionalized polyethylene, 7 parts of cycloolefin (Japan Zeon K26R), and 6 parts of carbon black masterbatch (Beihua High-tech PECB4025A), add them into a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them into the feeding scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and extrude, cool, pull and cut the materials smoothly.

[0040] Example 4

[0041] 1) Preparation of functionalized polyethylene: 60 parts of maleic anhydride grafted polyethylene (Jiayirong CMG5804) and 40 parts of graphene oxide (Xianfeng Nano, thickness <5 nm, sheet diameter 20 um) were placed in a high-speed stirring mixer at 210°C, a rotation speed of 800 r / min, and a reaction time of 20 min. The obtained premix was passed through a flat vulcanizer and molded into 2.0 mm thin sheets at 210°C, cut into pieces, and then the premix was melt-mixed through a single screw extruder (five-zone temperature range 180°C / 195°C / 195°C / 190°C / 180°C) to prepare functionalized polyethylene;

[0042] 2) Preparation of anti-sag pipe: Weigh 83 parts of high-density polyethylene (Wanhua 23050), 8 parts of functionalized polyethylene, 3 parts of cycloolefin (Japan Zeon K26R), and 6 parts of carbon black masterbatch (Beihua High-tech PECB4025A), add them into a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them into the feeding scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and extrude, cool, pull and cut the materials smoothly.

[0043] Comparative Example 1

[0044] Preparation of anti-sag pipe: Weigh 95 parts of high-density polyethylene (Wanhua 23050) and 5 parts of carbon black masterbatch (Beihua High-Tech PECB4025A), add them to a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them to the discharge scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and extrude, cool, pull and cut the materials smoothly.

[0045] Comparative Example 2

[0046] Preparation of anti-sag pipe: Weigh 94 parts of high-density polyethylene (Wanhua 23050), 5 parts of carbon black masterbatch (Beihua High-Tech PECB4025A), and 1 part of ultra-high molecular weight polyethylene (Celanese 4112), add them into a high-speed mixer (speed 1500r / min, temperature room temperature, time 5min) and mix them evenly, feed them into the discharge scale of the single-screw extruder, maintain the extrusion process temperature at 200℃±15℃, and extrude, cool, pull and cut the materials smoothly.

[0047] The product properties of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0048] Table 1 Product performance of Examples 1-4 and Comparative Examples 1-2

[0049]

Claims

1. A pipeline material comprising the following components in parts by weight: 75-95 parts of high-density polyethylene, preferably 80-90 parts; 2-10 parts of functionalized polyethylene, preferably 4-8 parts; 2-8 parts of cycloolefin polymer, preferably 3-7 parts; Carbon black masterbatch 1-7 parts, preferably 2-6 parts.

2. The pipe material according to claim 1, wherein: The high-density polyethylene has a melt index of 0.15-0.25 g / 10 min at 190°C and 5 kg test conditions, and a density of 0.945-0.955 g / cm 3 .

3. The pipe material according to claim 1, wherein: The functionalized polyethylene is obtained by reacting 50-80 parts of maleic anhydride grafted polyethylene (maleic anhydride grafting rate 0.5-2.0%) and 20-50 parts of graphene oxide (particle size 0.1-30um) as main raw materials.

4. The pipe material according to claim 3, wherein: The method for preparing functionalized polyethylene comprises: 50-80 parts of maleic anhydride grafted polyethylene and 20-50 parts of graphene oxide are placed in an internal mixer, reacted at 190-220° C., rotation speed 500-1500 r / min, for 10-30 minutes, and the obtained premix is ​​passed through a flat vulcanizer, molded into 0.5-2.0 mm thin sheets at 190-220° C., cut into pieces, and then the premix is ​​melt-mixed through a single-screw extruder to prepare functionalized polyethylene.

5. The pipe material according to claim 1, wherein: The melt index of the cycloolefin polymer under the test conditions of 280° C. and 2.16 kg is 20-70 g / 10 min.

6. The pipe material according to claim 1, wherein: The carbon black masterbatch is a polyethylene carrier carbon black masterbatch with a carbon black content of 38-42%.

7. The method for preparing the pipeline material according to any one of claims 1 to 6, comprising the following steps: High-density polyethylene, functional polyethylene, cycloolefin polymer and carbon black masterbatch are weighed in proportion, added into a high-speed mixer for uniform mixing, and fed into a single-screw extruder feed scale. The extrusion process temperature is maintained at 200°C±15°C, and the feed is extruded, cooled, pulled and cut smoothly.

8. The preparation method according to claim 7, wherein: The operating conditions of the high-speed mixer are a rotation speed of 1000-2000 r / min, room temperature, and 3-10 min.

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