Carbon black master batch with nano shell-core grafted coating structure for polyethylene gas pipe and preparation method of carbon black master batch

Abstract

The invention relates to a carbon black master batch with a nanometer shell-core grafting and coating structure for a polyethylene gas pipe and a preparation method of the carbon black master batch. Relates to the field of building plastic. The carbon black master batch for the polyethylene gas pipe produced by the invention contains a core-shell grafting coating structure, can be tightly combined with nano carbon black particles, and is compatible with a polyethylene base material, so that the master batch is easier to disperse and the carbon black is uniformly distributed during production. And with the coating of the grafted copolymer, the reinforcing and toughening effects of nano filling can be better exerted in subsequent use. The paint has the characteristics of good dispersibility, strong coloring power, stable performance and bright appearance. The master batch also has the effect of reinforcing and toughening the polyethylene base material, and the premix for the polyethylene gas pipe produced by using the master batch has the characteristics of stable quality, excellent performance and the like. The strength, the oxidation resistance and the hydrostatic strength of the water supply pipe are remarkably improved, and the water supply pipe is superior to the carbon black master batch prepared by a traditional dispersion method at present.

Description

Technical Field

[0001] The present invention relates to the field of building materials and plastics, and in particular to a carbon black masterbatch with a nano-shell-core graft coating structure for polyethylene gas pipes and a preparation method thereof. Background Art

[0002] Polyethylene (PE) gas pipelines are gradually replacing traditional steel pipes. The national standard GB15558.1-2015 for PE gas pipes and the international standard ISO4437-2014 control standards set strict performance indicators for PE gas pipes, including minimum required strength (MRS), resistance to slow crack growth (SCG), resistance to rapid crack propagation (RCP), and resistance to gas components. This places relatively strict demands on the raw materials, additives, and processing conditions of PE gas pipes. To meet these performance indicators, PE gas pipes are currently made from PE80 or PE100 polyethylene resins mixed with auxiliary materials such as carbon black, which are then granulated and formed into pipes.

[0003] The most common solution is to convert carbon black into a masterbatch for reuse. However, because carbon black is an inorganic material, its interfacial compatibility with PE is poor. To improve the uniform dispersion of carbon black in the mixed ingredients, traditional PE pipe carbon black masterbatch preparations often add coupling agents to promote uniform dispersion. However, pigment-based carbon black has few surface groups and cannot form a good organic-inorganic bridge with the coupling agent, resulting in dispersibility that does not meet the required performance. Furthermore, the addition of carbon black can degrade the performance of the base material PE80 or PE100, and can even affect other properties of subsequent pipes. This is a common problem with carbon black masterbatches currently used in PE gas pipeline mixing ingredients on the market.

[0004] Therefore, there is an urgent need for a carbon black masterbatch for polyethylene gas pipes that has good dispersibility without affecting the performance of PE pipes. Summary of the Invention

[0005] The purpose of the present invention is to provide a nano-shell core grafted coated structured carbon black masterbatch for polyethylene gas pipes and a preparation method thereof, so as to solve the problem of poor dispersibility of the carbon black masterbatch for polyethylene gas pipes.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes comprises the following components in parts by weight:

[0008] Component A: 38-41 parts of nano carbon black, 3-5 parts of EVA (ethylene-vinyl acetate copolymer) wax, 0.2-0.4 parts of initiator, 3-5 parts of second copolymer, 3-4 parts of brightening dispersant;

[0009] Component B: 50-58 parts of polyethylene resin, 1.5-2 parts of maleic anhydride, 0.1-0.2 parts of processing flow agent, 0.1-0.15 parts of hindered phenol antioxidant, 0.15-0.2 parts of phosphite antioxidant, 0.1-0.15 parts of ultraviolet absorber, 0.1-0.15 parts of light stabilizer, 0.2-0.3 parts of heat stabilizer, 0.1-0.15 parts of high-temperature white oil.

[0010] As a further embodiment of the present invention, in component A, the EVA wax has an ethylene content of 18-22%, a melting point of 91-93° C., a density of 0.91-0.93 g / cm 3 , and a viscosity of 580-610 mPs.s.

[0011] As a further solution of the present invention, in component A, the particle size of the nano carbon black is 18-22 nm.

[0012] As a further embodiment of the present invention, in component A, the initiator is any one of dicumyl peroxide (DCP), benzoyl peroxide (BPO), and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (DBPH).

[0013] As a further embodiment of the present invention, in component A, the second copolymer is styrene.

[0014] As a further embodiment of the present invention, in component A, the brightening dispersant is TAS-2A.

[0015] As a further embodiment of the present invention, in component B, the polyethylene resin is PE100 grade polyethylene resin particles, and has a melt index of 0.25-0.4 g / 10 min at a rated temperature of 190° C. and a rated load of 5 kg.

[0016] Furthermore, the polyethylene resin is PE100 grade HDPE.

[0017] As a further embodiment of the present invention, in component B, the processing flow agent is PPA (polyphthalamide);

[0018] The hindered phenol antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate] (1010) or octadecylβ-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate (1076);

[0019] The phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (168) or bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (626);

[0020] The UV absorber is 2-hydroxy-4-n-octyloxybenzophenone (UV531);

[0021] The light stabilizer is bis(2,2,6,6-tetramethylpiperidinyl) sebacate (JY-770);

[0022] The heat stabilizer is zinc stearate or calcium stearate.

[0023] A method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes comprises the following steps:

[0024] S1 component A prepares pretreated nano carbon black:

[0025] The nano carbon black was heated to 105-115°C, stirred at a speed of 800-1000 r / min for 10-15 minutes, EVA wax was added, and stirring was continued for 10-20 minutes. The mixture was heated to 120-130°C, an initiator and a second copolymer were sprayed and added, and the mixture was stirred at a speed of 1300-1500 r / min for 20-30 minutes. The mixture was cooled to 70-80°C, a bright dispersant was added, and stirring was continued for 10-15 minutes. The mixture was cooled to room temperature (25-30°C) and stirring was stopped to obtain pretreated nano carbon black, which was recorded as material A.

[0026] S2 component B prepares masterbatch base:

[0027] At room temperature, polyethylene resin, maleic anhydride, processing flow agent, hindered phenol antioxidant, phosphite antioxidant, UV absorber, light stabilizer, stabilizer and high temperature white oil were mixed at a speed of 800-1000 r / min for 10-15 minutes to obtain a masterbatch base material, which was recorded as material B;

[0028] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0029] S4: Add material A1 to material B, mix at room temperature at a speed of 800-1000 r / min for 10-15 minutes to obtain material C;

[0030] S5 uses a twin-screw granulator. Material C is added from the main feeding port and material A2 is added from the side feeding port. After melt dispersion, extrusion granulation and drying, the finished product is obtained.

[0031] As a further solution of the present invention, the aspect ratio of the twin-screw granulator is ≥52:1, and the screw thread combination is a medium shear high mixing combination.

[0032] Furthermore, the aspect ratio of the twin-screw granulator is 52:1, the temperature of each section of the barrel is: 140-160°C in zones 1-3, 165-170°C in zone 4, 180-185°C in zone 5, 180-185°C in zone 6, 185-190°C in zones 7-10, 180-185°C in zone 11, and 175-180°C for the screen changer and die head; the feed ratio of the main material to the side feed is 80:20.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention provides a nano-shell core-grafted coated carbon black masterbatch for polyethylene gas pipes. By surface grafting and coating the nano-carbon black, the dual effects of physical coating with EVA wax and chemical grafting with styrene are utilized to form a core-shell structure, significantly improving the dispersibility of the carbon black and enhancing the interfacial bonding between the carbon black and the resin. At the same time, the masterbatch does not cause a decrease in the performance of the base material, and has the additional effect of strengthening and toughening the base material. It is an ideal dyeing material for producing high-end PE100 gas pipeline mixed ingredients.

[0035] 2. In the preparation process of the present invention, EVA wax is first used to pre-coat carbon black. The polar vinyl acetate (VA) segment of the EVA wax adsorbs the carbon black surface, and the non-polar ethylene segment is compatible with the polyethylene resin to form a "bridge" effect. The initiator decomposes to generate free radicals, which trigger the polymerization of styrene on the carbon black surface to form a polystyrene medium layer. The benzene ring of polystyrene and the carbon black π-π conjugation effect enhance adsorption, and at the same time, the compatibility of its non-polar chain with the polyethylene resin is improved, thereby effectively solving the agglomeration problem caused by the high specific surface area of nano carbon black; a distributed mixing method is used to preliminarily disperse half the weight of the pretreated nano carbon black (A1) in the masterbatch base material to form a "dilution effect" to avoid insufficient shear caused by subsequent direct high-concentration addition; the side feeding port is located at the rear section of the melting section, and the remaining half the weight of the pretreated nano carbon black (A2) is added when the resin is already molten, and is instantly dispersed by high shear force to avoid degradation caused by long-term high-temperature residence, ensuring uniform melting without damaging the carbon black grafted layer, and shortening the mixing time.

[0036] 3. The carbon black masterbatch for polyethylene gas pipes produced by the present invention contains a core-shell graft coating structure that allows for tight bonding with nano-carbon black particles and compatibility with the polyethylene base material. This allows for easier dispersion and even carbon black distribution during masterbatch production. Furthermore, the graft copolymer coating further enhances the reinforcing and toughening effects of the nano-filler during subsequent use. This masterbatch exhibits excellent dispersibility, strong coloring ability, stable performance, and a bright appearance. This masterbatch also strengthens and toughens the polyethylene base material. Polyethylene gas pipe premixes produced using this masterbatch exhibit stable quality and excellent performance. This significantly improves the strength, antioxidant capacity, and hydrostatic strength of water supply pipes. This is superior to carbon black masterbatches produced using conventional dispersion methods. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0038] The terms used in the examples of this application are for the purpose of describing specific implementation rules only and are not intended to limit this application. The singular forms "a", "an", "the" and "the" used in the implementation rules of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0040] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0041] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0042] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0043] In the following examples and comparative examples, the particle size of the nano carbon black is 20±2 nm, and the ethylene content in the selected EVA wax is 20%;

[0044] The polyethylene resin used was trimodal HDPE produced by LyondellBasell's Hostalen ACP low-pressure slurry process technology, with a melt index of 0.20-0.24 (190°C, 5.0kg); the high-temperature white oil used was Sinopec Great Wall Lubricant 4408.

[0045] The following is further explained with reference to specific embodiments.

[0046] Example 1

[0047] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0048] S1 component A prepares pretreated nano carbon black:

[0049] Use a high-speed mixer to add 39 parts of nano-carbon black, heat to 110 ° C, stir at a speed of 800 r / min for 15 minutes, add 4 parts of EVA wax, continue stirring for 10 minutes, heat the mixture to 120 ° C, spray 0.3 parts of initiator (DCP) and 4 parts of the second copolymer (polystyrene) through the spray feed port on the upper cover of the high-speed mixer, stir at a speed of 1300 r / min for 20 minutes, cool to 70 ° C by jacket cooling, add 4 parts of bright dispersant (TAS-2A), continue stirring for 10 minutes, cool to room temperature and stop stirring to obtain pretreated nano-carbon black, recorded as material A;

[0050] S2 component B prepares masterbatch base:

[0051] Under room temperature conditions, 53 parts of polyethylene resin, 2 parts of maleic anhydride, 0.1 parts of processing flow agent (PPA), 0.1 parts of hindered phenol antioxidant (1010), 0.2 parts of phosphite antioxidant (168), 0.1 parts of ultraviolet absorber (UV531), 0.1 parts of light stabilizer (JY-770), 0.2 parts of heat stabilizer (zinc stearate) and 0.1 parts of high-temperature white oil were mixed at a speed of 800 r / min for 10 minutes to obtain a masterbatch base material, which was recorded as material B;

[0052] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0053] S4: Add material A1 to material B, mix at room temperature at a speed of 800 r / min for 10 min to obtain material C;

[0054] S5 uses a twin-screw granulator. Material C is added from the main feed port and material A2 is added from the side feed port. After being melted and dispersed in the granulator, the materials are extruded from the die head and cut into strands and pelletized. Finally, they are dried to obtain the finished product.

[0055] The length-to-diameter ratio of the twin-screw granulator is 52:1, the thread combination is a medium-shear high-mixing combination, the temperature of each section of the barrel is: 140-160°C in zones 1-3, 170°C in zone 4, 185°C in zone 5, 185°C in zone 6, 185-190°C in zones 7-10, 180°C in zone 11, the screen changer and die head are 175-180°C, and the feed ratio of main material to side feed is 80:20.

[0056] Example 2

[0057] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0058] S1 component A prepares pretreated nano carbon black:

[0059] Use a high-speed mixer to add 40 parts of nano-carbon black, heat to 110 ° C, stir at a speed of 1000 r / min for 15 minutes, add 4 parts of EVA wax, continue stirring for 20 minutes, heat the mixture to 125 ° C, spray 0.3 parts of initiator (DCP) and 3 parts of the second copolymer (polystyrene) through the spray feed port on the upper cover of the high-speed mixer, stir at a speed of 1400 r / min for 20 minutes, cool to 70 ° C by jacket cooling, add 4 parts of bright dispersant (TAS-2A), continue stirring for 10 minutes, cool to room temperature and stop stirring to obtain pretreated nano-carbon black, recorded as material A;

[0060] S2 component B prepares masterbatch base:

[0061] Under room temperature conditions, 52 parts of polyethylene resin, 1.5 parts of maleic anhydride, 0.1 parts of processing flow agent (PPA), 0.1 parts of hindered phenol antioxidant (1010), 0.2 parts of phosphite antioxidant (168), 0.1 parts of ultraviolet absorber (UV531), 0.1 parts of light stabilizer (JY-770), 0.2 parts of heat stabilizer (zinc stearate) and 0.1 parts of high-temperature white oil were mixed at a speed of 1000 r / min for 15 minutes to obtain a masterbatch base material, which was recorded as material B;

[0062] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0063] S4: Add material A1 to material B, mix at room temperature at a speed of 800 r / min for 10 min to obtain material C;

[0064] S5 is the same as in Example 1.

[0065] Example 3

[0066] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0067] S1 component A prepares pretreated nano carbon black:

[0068] Use a high-speed mixer to add 40 parts of nano-carbon black, heat to 115 ° C, stir at a speed of 1000 r / min for 15 minutes, add 5 parts of EVA wax, continue stirring for 15 minutes, heat the mixture to 130 ° C, spray 0.3 parts of initiator (BPO) and 4 parts of the second copolymer (polystyrene) through the spray feed port on the upper cover of the high-speed mixer, stir at a speed of 1500 r / min for 30 minutes, cool to 75 ° C by jacket cooling, add 4 parts of bright dispersant (TAS-2A), continue stirring for 15 minutes, cool to room temperature and stop stirring to obtain pretreated nano-carbon black, recorded as material A;

[0069] S2 component B prepares masterbatch base:

[0070] Under room temperature conditions, 51 parts of polyethylene resin, 2 parts of maleic anhydride, 0.2 parts of processing flow agent (PPA), 0.1 parts of hindered phenol antioxidant (1010), 0.2 parts of phosphite antioxidant (168), 0.1 parts of ultraviolet absorber (UV531), 0.1 parts of light stabilizer (JY-770), 0.2 parts of heat stabilizer (zinc stearate) and 0.1 parts of high-temperature white oil were mixed at a speed of 1000 r / min for 15 minutes to obtain a masterbatch base material, which was recorded as material B;

[0071] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0072] S4: Add material A1 to material B, mix at room temperature at a speed of 1000 r / min for 15 min to obtain material C;

[0073] S5 is the same as in Example 1.

[0074] Example 4

[0075] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0076] S1 component A prepares pretreated nano carbon black:

[0077] Using a high-speed mixer, 41 parts of nano-carbon black were added, the temperature was raised to 115°C, and the mixture was stirred at a speed of 1000 r / min for 15 minutes. 3 parts of EVA wax were added and the stirring was continued for 20 minutes. The mixture was heated to 120°C, and 0.3 parts of initiator (DBPH) and 4 parts of the second copolymer (polystyrene) were sprayed through the spray feed port on the upper cover of the high-speed mixer. After stirring at a speed of 1400 r / min for 30 minutes, the mixture was cooled to 70°C by jacket cooling, and 4 parts of bright dispersant (TAS-2A) were added. The mixture was stirred for 15 minutes, cooled to room temperature and the stirring was stopped to obtain pretreated nano-carbon black, which was recorded as material A;

[0078] S2 component B prepares masterbatch base:

[0079] Under room temperature conditions, 54 parts of polyethylene resin, 1.5 parts of maleic anhydride, 0.2 parts of processing flow agent (PPA), 0.15 parts of hindered phenol antioxidant (1010), 0.15 parts of phosphite antioxidant (168), 0.15 parts of ultraviolet absorber (UV531), 0.1 parts of light stabilizer (JY-770), 0.25 parts of heat stabilizer (zinc stearate) and 0.1 parts of high-temperature white oil were mixed at a speed of 1000 r / min for 15 minutes to obtain a masterbatch base material, which was recorded as material B;

[0080] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0081] S4: Add material A1 to material B, mix at room temperature at a speed of 1000 r / min for 15 min to obtain material C;

[0082] S5 is the same as in Example 1.

[0083] Example 5

[0084] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0085] S1 component A prepares pretreated nano carbon black:

[0086] Use a high-speed mixer to add 38 parts of nano carbon black, heat to 115 ° C, stir at a speed of 900 r / min for 15 minutes, add 5 parts of EVA wax, continue stirring for 20 minutes, heat the mixture to 125 ° C, spray 0.3 parts of initiator (DCP) and 4 parts of the second copolymer (polystyrene) through the spray feed port on the upper cover of the high mixer, stir at a speed of 1400 r / min for 30 minutes, cool to 80 ° C by jacket cooling, add 4 parts of bright dispersant (TAS-2A), continue stirring for 15 minutes, cool to room temperature and stop stirring to obtain pretreated nano carbon black, recorded as material A;

[0087] S2 component B prepares masterbatch base:

[0088] Under room temperature conditions, 58 parts of polyethylene resin, 1.5 parts of maleic anhydride, 0.2 parts of processing flow agent (PPA), 0.15 parts of hindered phenol antioxidant (1010), 0.2 parts of phosphite antioxidant (168), 0.1 parts of ultraviolet absorber (UV531), 0.15 parts of light stabilizer (JY-770), 0.3 parts of heat stabilizer (zinc stearate) and 0.15 parts of high-temperature white oil were mixed at a speed of 1000 r / min for 15 minutes to obtain a masterbatch base material, which was recorded as material B;

[0089] S3: Divide the pretreated nano carbon black into two equal parts by weight, which are recorded as material A1 and material A2;

[0090] S4: Add material A1 to material B, mix at room temperature at a speed of 1000 r / min for 15 min to obtain material C;

[0091] S5 is the same as in Example 1.

[0092] Comparative Example 1

[0093] This embodiment provides a method for preparing a nano-shell-core graft-coated structured carbon black masterbatch for polyethylene gas pipes, comprising the following steps:

[0094] Use a high-speed mixer to add 40 parts of nano carbon black and 1.5 parts of titanate coupling agent, stir and mix at a speed of 1000 r / min for 15 minutes, then add 54 parts of polyethylene resin, 5 parts of polyethylene wax, 0.1 parts of hindered phenol antioxidant (1010), 0.2 parts of phosphite antioxidant (168), 0.1 parts of ultraviolet absorber (UV531), 0.1 parts of light stabilizer (JY-770), 0.2 parts of heat stabilizer (zinc stearate), and stir at a speed of 1000 r / min. The mixture was stirred at high speed for 20 minutes, and the evenly dispersed mixture was metered into the twin-screw granulator from the main feeding port. After melt dispersion in the granulator, it was extruded from the die and pelletized. Finally, it was dried to obtain the finished product. The twin-screw with an aspect ratio of 52:1 was also used. The temperature of each zone was controlled as follows: 140-160℃ for zones 1-3, 170℃ for zone 4, 185℃ for zone 5, 185℃ for zone 6, 185℃ for zones 7-10, 180℃ for zone 11, and 175-180℃ for screen changer and die.

[0095] Comparative Example 2

[0096] Purchased sample A, brand: PECB4025.

[0097] Comparative Example 3

[0098] Purchased sample B, brand: Cabot HD2776.

[0099] Comparative Example 4

[0100] This comparative example provides a method for preparing a nanoshell-core grafted coated structured carbon black masterbatch for polyethylene gas pipes. The method differs from Example 1 in that the S3 operation is not performed, and material A is directly added to material B and mixed evenly, and then extruded and granulated from the main feed port of a twin-screw granulator. The remaining steps and parameters remain the same.

[0101] With reference to the "Industry Standard for Carbon Black Masterbatch for Polyethylene (PE) Pipe Compounding for Water Supply - QB / T4132-2010", the carbon black masterbatch in Examples 1-5 and Comparative Examples 1-4 was subjected to performance tests, wherein the melt mass flow rate test was in accordance with GB / T3682; the carbon black content test was in accordance with GB / T13021; the carbon black dispersion level was in accordance with GB / T18251; the volatile matter test was in accordance with GB / T15558.1; and the thermal stability (oxidation induction time OIT) test was in accordance with ISO11357-6.

[0102] The above test results are shown in Table 1.

[0103] Table 1

[0104]

[0105] The test results in Table 1 indicate that the carbon black masterbatches prepared in Examples 1-5 all meet the various specifications of the industry standard QB / T4132-2010. Furthermore, compared to conventional methods employing coupling agent pretreatment and modification, the present invention utilizes a dual-action grafting and coating process on the surface of the nanocarbon black, utilizing both physical coating with EVA wax and chemical grafting with styrene to form a core-shell structure, significantly improving the dispersion of the carbon black. Furthermore, the separate feeding and extrusion method further ensures product quality. The resulting carbon black masterbatches exhibit excellent performance, even surpassing commercially available products, making them a viable alternative.

[0106] In order to further verify the advantages of the carbon black masterbatch prepared by the present invention for producing PE100 mixed materials for gas pipes, samples of Examples 1-5 and Comparative Examples 1-4 were taken, and polyethylene gas pipe base materials were mixed with the added amount of 6% to produce secondary mixed materials for gas pipes using a twin-screw extruder. The relevant indicators and mechanical properties of the "Standard for Buried Polyethylene Pipes for Gas GB15558.1" were used for testing, and compared with blank base materials. Among them, the melt mass flow rate test was based on GB / T3682; the density test was based on GB / T1033; the carbon black content test was based on GB / T13021; the carbon black dispersion level was based on GB / T18251; the volatile matter test was based on GB / T15558.1; and the thermal stability (oxidation induction time OIT) test was based on ISO11357-6. The above test results are shown in Table 2.

[0107] Table 2

[0108] Mechanical properties tests include: tensile elastic modulus test in accordance with GB / T1040.2; tensile yield stress test in accordance with GB / T1040.2; elongation at break test in accordance with GB / T9341; simply supported beam notched impact strength test in accordance with GB / T1843; load deformation temperature test in accordance with GB / T1634.2; the mechanical properties test results are shown in Table 3.

[0109] Table 3

[0110]

[0111] As can be seen from Tables 2 and 3, the strength and toughness of the PE100 mixed material for gas pipes prepared using the carbon black masterbatch prepared by the present invention are improved, avoiding the problem of decreased mechanical properties caused by the addition of carbon black masterbatch. The material is significantly better than the carbon black masterbatch prepared by dispersion using a conventional silane coupling agent. At the same time, the separate feeding of the carbon black masterbatch during the extrusion process can further improve the dispersibility of the carbon black, showing excellent competitiveness compared to commercial products.

[0112] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0113] The above disclosures are only a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A nano-shell core grafted coated structured carbon black masterbatch for polyethylene gas pipes, characterized in that: According to parts by weight, it includes the following components: Component A: 38-41 parts of nano carbon black, 3-5 parts of EVA wax, 0.2-0.4 parts of initiator, 3-5 parts of second copolymer, 3-4 parts of brightening dispersant; Component B: 50-58 parts of polyethylene resin, 1.5-2 parts of maleic anhydride, 0.1-0.2 parts of processing flow agent, 0.1-0.15 parts of hindered phenol antioxidant, 0.15-0.2 parts of phosphite antioxidant, 0.1-0.15 parts of ultraviolet absorber, 0.1-0.15 parts of light stabilizer, 0.2-0.3 parts of heat stabilizer, 0.1-0.15 parts of high-temperature white oil.

2. The nano-shell-core grafted carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component A, the EVA wax has an ethylene content of 18-22%, a melting point of 91-93° C., a density of 0.91-0.93 g / cm 3 , and a viscosity of 580-610 mPs.s.

3. The nano-shell-core grafted coated carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component A, the particle size of the nano carbon black is 18-22 nm.

4. The nano-shell-core grafted carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component A, the initiator is any one of dicumyl peroxide, benzoyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

5. The nano-shell-core grafted coated carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component A, the second copolymer is styrene; in component A, the brightening dispersant is TAS-2A.

6. The nano-shell-core grafted coated carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component B, the polyethylene resin is PE100 grade polyethylene resin particles, and has a melt index of 0.25-0.4 g / 10 min at a rated temperature of 190° C. and a rated load of 5 kg.

7. The nano-shell core grafted coated structured carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component B, the processing flow agent is polyphthalamide; The UV absorber is 2-hydroxy-4-n-octyloxybenzophenone; The light stabilizer is bis(2,2,6,6-tetramethylpiperidinyl) sebacate.

8. The nano-shell-core grafted carbon black masterbatch for polyethylene gas pipe according to claim 1, characterized in that: In component B, the hindered phenol antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate] or octadecylβ-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate; The phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (or bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite); The heat stabilizer is zinc stearate or calcium stearate.

9. A method for preparing a nano-shell core grafted coated structured carbon black masterbatch for polyethylene gas pipes, for preparing the nano-shell core grafted coated structured carbon black masterbatch for polyethylene gas pipes according to claim 1, characterized in that: The following steps are involved: S1: heating the nano carbon black to 105-115°C, stirring at a speed of 800-1000 r / min for 10-15 minutes, adding EVA wax, continuing to stir for 10-20 minutes, heating the mixture to 120-130°C, spraying the initiator and the second copolymer, stirring at a speed of 1300-1500 r / min for 20-30 minutes, cooling to 70-80°C, adding the brightening dispersant, continuing to stir for 10-15 minutes, cooling to room temperature and stopping stirring to obtain material A; S2: At room temperature, polyethylene resin, maleic anhydride, processing flow agent, hindered phenol antioxidant, phosphite antioxidant, UV absorber, light stabilizer, stabilizer and high temperature white oil were mixed at a speed of 800-1000 r / min for 10-15 minutes to obtain material B; S3: Divide material A into two equal parts, record them as material A1 and material A2; S4: Add material A1 to material B and mix at room temperature at a speed of 800-1000 r / min for 10-15 min to obtain material C; S5: Using a twin-screw granulator, material C is added from the main feed port and material A2 is added from the side feed port. After melt dispersion, extrusion granulation, and drying, a nano-shell-core grafted coated structured carbon black masterbatch for polyethylene gas pipes is obtained.

10. The method for preparing a nano-shell-core graft-coated carbon black masterbatch for polyethylene gas pipes according to claim 9, characterized in that: The temperature of each section of the twin-screw granulator barrel is: 140-160°C in zones 1-3, 165-170°C in zone 4, 180-185°C in zone 5, 180-185°C in zone 6, 185-190°C in zones 7-10, 180-185°C in zone 11, and 175-180°C for the screen changer and die head; the feed ratio of main material to side feed is 80:20.

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