3PE anticorrosion polyethylene special material with bonding anticorrosion function, preparation method thereof and anticorrosion steel pipe prepared from 3PE anticorrosion polyethylene special material

Abstract

The invention relates to a 3PE anticorrosion polyethylene special material with a bonding anticorrosion function, a preparation method and an anticorrosion steel pipe thereof. The 3PE anticorrosive polyethylene special material is prepared from the following raw materials in parts by weight: 10 to 40 parts of maleic anhydride grafted polyethylene, 20 to 50 parts of high-density polyethylene, 20 to 40 parts of linear low-density polyethylene, 3 to 10 parts of elastomer, 5 to 7 parts of carbon black master batch and 0.5 to 3 parts of anti-aging additive. The anti-aging 3PE anti-corrosion special material is obtained by blending the 3PE anti-corrosion special material and carrying out twin-screw melt granulation. The 3PE anticorrosive polyethylene special material provided by the invention has double functions of bonding and corrosion resistance, and also has the advantages of bonding of an epoxy bottom layer, excellent mechanical properties, excellent environmental stress cracking resistance, good processability and excellent aging resistance, and the change rate of the melt mass flow rate of a product subjected to thermal aging at 100 DEG C for 4800 hours is not greater than 35%.

Description

Technical Field

[0001] The present invention relates to the field of 3PE anti-corrosion, and specifically to a 3PE special material for steel pipeline anti-corrosion, a preparation method thereof and an anti-corrosion steel pipe using the material, and more specifically to a 3PE anti-corrosion polyethylene special material with bonding anti-corrosion function, a preparation method and an anti-corrosion steel pipe thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] 3PE anti-corrosion is a three-layer anti-corrosion technology composed of fused epoxy / polyethylene adhesive / extruded polyethylene layers, used for the surface protection of buried steel pipes. The existing structure consists of the following three layers: the bottom layer is fused epoxy (60-80μm); the middle layer is maleic anhydride grafted modified adhesive (170-250μm); the surface layer is extruded polyethylene special material (about 2.0-4.2mm). In the three-layer structure, the main function of epoxy is to directly bond with the surface of the steel pipe, with good chemical corrosion resistance and anti-cathodic stripping performance; it reacts with the active groups of the adhesive to form a chemical bond, ensuring that the overall anti-corrosion layer has good adhesion at higher temperatures. The middle layer is usually maleic anhydride grafted polyethylene adhesive. The polar anhydride functional group and the epoxy group of epoxy can react to form a chemical bond, so that the middle layer and the bottom layer form a good bond; and the non-polar ethylene part has a good affinity with the surface polyethylene special material, so the middle layer and the surface layer also have good bonding properties. The main function of the polyethylene surface layer is mechanical protection and anti-corrosion. The three-layer polyethylene anti-corrosion layer combines the excellent properties of the epoxy coating and the extruded polyethylene anti-corrosion layer, combining the interface characteristics and chemical resistance of the epoxy coating with the mechanical protection characteristics of the polyethylene anti-corrosion layer. According to relevant information, 3PE anti-corrosion can extend the life of buried pipelines to 50 years. It is currently considered to be the most advanced external anti-corrosion technology for oil, gas and water pipelines in the world. Therefore, 3PE anti-corrosion is very superior as the outer protective layer of buried pipelines. 3PE anti-corrosion steel pipes are mainly used for oil, gas and water transportation, and are currently recognized as pipelines with the best anti-corrosion effect.

[0004] In the existing 3PE anti-corrosion technology, epoxy anti-corrosion adopts spraying process, and adhesive and polyethylene special materials are wrapped on the surface of epoxy powder by extrusion coating or lateral extrusion. Two single-screw extruders are required to extrude adhesive and polyethylene special materials respectively. The coating process is only suitable for the anti-corrosion of steel pipes with smaller diameters. When the adhesive is wrapped on the epoxy surface, due to the thin thickness of the adhesive (170-250μm), the adhesive extrusion and wrapping process is prone to breakage, resulting in lack of adhesive in the anti-corrosion layer. If the breakage is not discovered, the epoxy layer and the outer protective polyethylene layer in the three-layer anti-corrosion structure cannot be combined together through chemical reaction, which will affect the overall anti-corrosion effect. Summary of the invention

[0005] In order to solve the problems in the prior art that adhesives and polyethylene special materials need to be extruded by two extruders during the anti-corrosion process, and the adhesive layer is thin, which leads to poor anti-corrosion performance caused by easy glue breaking during the extrusion process, the present invention proposes a 3PE special material with both bonding and anti-corrosion functions, a preparation method and an anti-corrosion steel pipe used therein. The 3PE anti-corrosion polyethylene special material is prepared by blending and twin-screw melt granulation by combining maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch, and anti-aging additives. Through the compounding of maleic anhydride grafted polyethylene with different polyethylenes, elastomers, and additives, the 3PE anti-corrosion special material of the present invention has the functions of bonding epoxy and anti-corrosion, excellent mechanical properties, excellent environmental stress cracking resistance, good processing performance, excellent aging resistance, and the melt mass flow rate change rate of the product after 4800h of thermal aging at 100°C is not more than 35%. The 3PE anti-corrosion special material of the present invention is coated on the surface of molten epoxy powder through an extrusion winding process, and the obtained anti-corrosion steel pipe can replace the traditional 3PE anti-corrosion steel pipe composed of three layers of epoxy, polyethylene adhesive and polyethylene anti-corrosion special material.

[0006] Specifically, the present invention is achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a 3PE anti-corrosion polyethylene special material, comprising: 10-40 parts of maleic anhydride grafted polyethylene, 20-50 parts of high-density polyethylene, 20-40 parts of linear low-density polyethylene, 3-10 parts of elastomer, 5-7 parts of carbon black masterbatch, and 0.5-3 parts of anti-aging additive.

[0008] The second aspect of the present invention provides a method for preparing a 3PE anti-corrosion polyethylene special material, comprising: maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch, and anti-aging additive, which are prepared by blending and twin-screw melt granulation.

[0009] Specifically, maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch, and anti-aging additive are mixed in proportion, and a screw extruder is used at 200-230° C. and a screw speed of 350-600 rpm to melt-blend and granulate to obtain 3PE special anti-corrosion material.

[0010] The third aspect of the present invention provides an anti-corrosion steel pipe prepared with a 3PE anti-corrosion polyethylene special material and / or a 3PE anti-corrosion polyethylene special material, which is coated on the surface of molten epoxy powder by an extrusion winding process. The obtained anti-corrosion steel pipe can replace the traditional 3PE anti-corrosion steel pipe composed of three layers of anti-corrosion of epoxy, polyethylene adhesive, and polyethylene anti-corrosion special material.

[0011] One or more embodiments of the present invention have the following beneficial effects:

[0012] 1) The 3PE anti-corrosion special material of the present invention has both bonding and anti-corrosion functions by combining maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch, and anti-aging additive. The traditional 3PE polyethylene special material does not have the bonding function, mainly because the formula does not contain components that are reactive with epoxy primer, such as maleic anhydride grafted polyethylene.

[0013] 2) It effectively solves the problem that the adhesive of the traditional 3PE anti-corrosion process is prone to breaking during the wrapping process due to its thin thickness. Through the combination of maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch, and anti-aging additives, the 3PE anti-corrosion special material of the present invention can play the dual functions of bonding of the adhesive of the traditional 3PE anti-corrosion material and anti-corrosion of the polyethylene special material. The 3PE anti-corrosion special material with dual functions of bonding and anti-corrosion of the present invention can replace the traditional 3PE anti-corrosion adhesive (the standard requires a thickness of 170-250μm) and polyethylene special material. Therefore, after the epoxy is sprayed on the surface of the steel pipe during the anti-corrosion process, there is no need to extrude and wrap a thinner adhesive layer. It is only necessary to extrude the 3PE anti-corrosion special material with dual functions of bonding and anti-corrosion of the present invention (the standard requires a thickness of 1.8-4.2mm). The thickness is large and the extrusion wrapping process will not cause the tape to break.

[0014] 3) The 3PE special anti-corrosion material ethylene of the present invention has the dual functions of bonding and anti-corrosion, and no adhesive is needed. Therefore, the anti-corrosion equipment can save a single-screw extruder for adhesive extrusion, reducing equipment investment.

[0015] 4) The 3PE anti-corrosion special material ethylene of the present invention has the dual functions of bonding and anti-corrosion, replacing the adhesive and 3PE special material in traditional 3PE anti-corrosion, simplifying the operation process in the anti-corrosion process and improving production efficiency.

[0016] 5) The 3PE anti-corrosion steel pipe using the 3PE special material of the present invention for anti-corrosion, combined with the 3PE special material of the present application having bonding and anti-corrosion functions, has comprehensive properties such as excellent mechanical properties, good processing properties, and outstanding resistance to long-term heat aging, which solves the problem of poor anti-corrosion effect caused by thin thickness of traditional 3PE anti-corrosion adhesives and easy breakage of adhesives during the anti-corrosion process. The combination of the 3PE anti-corrosion epoxy layer and the polyethylene special material layer is more reliable, avoiding the risk of the corrosion layer not being able to be organically combined due to the breakage of adhesives in the traditional 3PE anti-corrosion process without being discovered. Therefore, the 3PE anti-corrosion special material of the present invention can provide better protection for steel pipes and longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The following are the test and application effect data of the embodiments and comparative examples. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0020] The present invention is further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are for explanation rather than limitation of the present invention. The parts are all by mass.

[0021] In an embodiment of the present invention, a 3PE anti-corrosion polyethylene special material is provided, comprising: 10-40 parts of maleic anhydride grafted polyethylene, 20-50 parts of high-density polyethylene, 20-40 parts of linear low-density polyethylene, 3-10 parts of elastomer, 5-7 parts of carbon black masterbatch, and 0.5-3 parts of anti-aging additive.

[0022] In some embodiments, the maleic anhydride grafted polyethylene is maleic anhydride grafted high-density polyethylene, the melt mass flow rate under the action of 2.16 kg weight at 190° C. is 0.5-5 g / 10 min, and the maleic anhydride grafting rate is 0.5%-1.5%.

[0023] In some embodiments, the maleic anhydride grafted polyethylene is prepared by the following ratio and process: 90-100 parts of high-density polyethylene, 3-10 parts of propylene-based elastomer, 1-2 parts of maleic anhydride, and 0.02-0.2 parts of peroxide initiator; the grafting reaction is carried out by a twin-screw extruder at 200-300°C and a screw speed of 400-800rpm.

[0024] The high-density polyethylene in the maleic anhydride grafted polyethylene has a melt mass flow rate of 2-10 g / min at 190° C. under the action of a 2.16 kg weight.

[0025] In some embodiments, the high-density polyethylene described in the 3PE anti-corrosion polyethylene special material has a melt mass flow rate of 0.05-5g / 10min at 190°C and under the action of a 2.16kg weight.

[0026] The linear low-density polyethylene has a melt mass flow rate of 0.5-20 g / min at 190° C. and under the action of a 2.16 kg weight.

[0027] In some embodiments, the linear low-density polyethylene is a linear low-density polyethylene obtained by polymerization with a metallocene catalyst.

[0028] In some embodiments, the elastomer is at least one of ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-butadiene-styrene block copolymer (SEBS).

[0029] The carbon black masterbatch contains 40% to 60% carbon black, and the particle size of the carbon black is less than 25nm.

[0030] In some embodiments, the anti-aging aid is composed of one or more of hindered phenol antioxidants, sulfur-containing hindered phenol antioxidants, phosphite antioxidants, hindered amine light stabilizers, and acid absorbers.

[0031] The 3PE special anti-corrosion material prepared by the method provided in the embodiment of the present invention has a melt mass flow rate of 0.2-1.0 g / min at 190°C and under the action of a 2.16 kg weight, a yield strength greater than 15 MPa, a tensile strength greater than 25 MPa, an elongation at break greater than 600%, a Vicat softening point greater than 110°C, and a peel strength of epoxy bonding after steel pipe anti-corrosion: 20±5°C temperature, ≥300 N / cm; 60±5°C temperature, ≥150 N / cm; 80±5°C temperature, ≥80 N / cm.

[0032] Example 1

[0033] Maleic anhydride grafted polyethylene (M1): 90 parts of HDPE 7260 (Shandong Shouguang Luqing Petrochemical Co., Ltd., melt mass flow rate 8g / 10min (190°C, 2.16kg weight)), propylene-based elastomer Vistamaxx TM 10 parts of 3020FL (ExxonMobil Chemical Co., Ltd.), 2 parts of maleic anhydride, and 0.1 part of di-tert-butyl peroxide diisopropylbenzene as a peroxide initiator were mixed uniformly, and then grafted on a twin-screw extruder at 200° C. and a rotation speed of 450 rpm to obtain a maleic anhydride grafted polyethylene with a maleic anhydride grafting rate of 1.08% and a melt mass flow rate of 3.4 g / 10 min (190° C., 2.16 kg weight).

[0034] 3PE anti-corrosion special materials are composed according to Table 1:

[0035] Table 1 3PE special material ratio in Example 1

[0036]

[0037] The information of the raw materials used in Example 1 is as follows:

[0038] HDPE: 6000F, melt mass flow rate 0.54 g / 10 min (190 ° C, 5 kg weight), Qilu Petrochemical;

[0039] Metallocene linear low-density polyethylene (LLDPE): HPR3518CB, melt mass flow rate 3.5 g / 10 min (190 ° C, 2.16 kg weight), Dushanzi Petrochemical;

[0040] Elastomer: Ethylene-octene copolymer 5017, Wanhua Chemical Group Co., Ltd.

[0041] Carbon black masterbatch: EM105G, carbon black content 42%, carbon black particle size less than 25nm, Shandong Donghong Pipe Industry Co., Ltd.

[0042] Anti-aging agent: It is mixed with 70% of hindered phenol antioxidant antioxidant 3114 (BASF), 20% of phosphite antioxidant 626 (Linyi Sanfeng Chemical Co., Ltd.), and 10% of hindered amine light stabilizer 783 (BASF).

[0043] The specific steps for preparing 3PE anti-corrosion special materials are:

[0044] The components are uniformly mixed in a mixer according to the proportion, added into a twin-screw extruder, melt-blended at 210° C. and 500 rpm, and granulated to obtain 3PE anti-corrosion special material.

[0045] Testing and application of 3PE anti-corrosion special materials:

[0046] The melt flow rate, yield strength, tensile strength, nominal strain at crack, Vicat softening point, oxidation induction time, and heat aging at 100°C for 4800h were tested in accordance with GB / T23257-2017. The relevant data are shown in Table 5.

[0047] Select DN820 steel pipe, shot blast and remove rust from the steel pipe, then preheat with medium frequency, spray epoxy, and extrude 3PE anti-corrosion special material before the epoxy gels. The 3PE special material is extruded at 215℃, and the thickness of the anti-corrosion layer is controlled to be 3.0-3.5mm. The peel strength at 20, 60, and 80℃ is tested according to GB / T23257. The appearance of the 3PE anti-corrosion outer layer is shown in Table 5.

[0048] Example 2

[0049] Maleic anhydride grafted polyethylene (M2): 97 parts of HDPE8041 (Taiwan Plastics Industry Co., Ltd., melt mass flow rate 4g / 10min (190°C, 2.16kg weight)), propylene-based elastomer NORDEL TM 3 parts of IP 4640 (Dow Chemical), 1 part of maleic anhydride, and 0.08 parts of peroxide initiator 2,5-dimethyl-2,5-di(2-ethylhexanoyl peroxide)hexane were mixed and uniformly mixed, and then grafted with a twin-screw extruder at 250° C. and a rotation speed of 550 rpm to obtain a maleic anhydride grafted polyethylene with a maleic anhydride grafting rate of 0.82% and a melt mass flow rate of 1.2 g / 10 min (190° C., 2.16 kg weight).

[0050] 3PE anti-corrosion special materials are composed according to Table 2:

[0051] Table 2 3PE special material ratio in Example 2

[0052]

[0053]

[0054] The information of the raw materials used in Example 2 is as follows:

[0055] HDPE: DGDB2480, melt mass flow rate 0.32 g / 10 min (190 ° C, 5 kg weight), Qilu Petrochemical;

[0056] Metallocene linear low-density polyethylene (LLDPE): VL0005, melt mass flow rate 5.0 g / 10 min (190 ° C, 2.16 kg weight), Daelim Chemical, South Korea;

[0057] Elastomer: SEBS 501, Sinopec Hunan Petrochemical Co., Ltd.;

[0058] Carbon black masterbatch: EM105G, carbon black content 42%, Shandong Donghong Pipe Industry Co., Ltd.

[0059] Anti-aging agent: It is mixed with 60% of hindered phenol antioxidant 1010 (Jiyi Holding Group), 30% of bis(2,4-dicumylphenyl)pentaerythritol-diphosphite (Jiyi Holding Group), and 10% of hindered amine light stabilizer 770 (BASF).

[0060] The specific steps for preparing 3PE anti-corrosion special materials are:

[0061] The components were mixed evenly in a mixer according to the proportion, added into a twin-screw extruder, melt-blended at 220° C. and 450 rpm, and granulated to obtain 3PE special anti-corrosion material.

[0062] Testing and application of 3PE anti-corrosion special materials:

[0063] The melt flow rate, yield strength, tensile strength, nominal strain at crack, Vicat softening point, oxidation induction time, and heat aging at 100°C for 4800h were tested in accordance with GB / T23257-2017. The relevant data are shown in Table 5.

[0064] Select DN820 steel pipe, shot blast and remove rust from the steel pipe, then preheat with medium frequency, spray epoxy, and extrude 3PE anti-corrosion special material before the epoxy gels. The 3PE special material is extruded at 225℃, and the thickness of the anti-corrosion layer is controlled to be 3.0-3.5mm. The peel strength at 20, 60, and 80℃ is tested according to GB / T23257. The appearance of the 3PE anti-corrosion outer layer is shown in Table 5.

[0065] Comparative Example 1

[0066] The maleic anhydride grafted polyethylene (M1) is the same as that in Example 1, and the raw materials used are the same as those in Example 1.

[0067] The 3PE anti-corrosion special material in Comparative Example 1 is composed according to Table 3:

[0068] Table 3 3PE special material ratio in comparative example 1

[0069]

[0070]

[0071] The specific steps for preparing 3PE anti-corrosion special materials are:

[0072] The components are uniformly mixed in a mixer according to the proportion, added into a twin-screw extruder, melt-blended at 210° C. and 500 rpm, and granulated to obtain 3PE anti-corrosion special material.

[0073] Testing and application of 3PE anti-corrosion special materials:

[0074] The melt flow rate, yield strength, tensile strength, nominal strain at crack, Vicat softening point, oxidation induction time, and heat aging at 100°C for 4800h were tested in accordance with GB / T23257-2017. The relevant data are shown in Table 5.

[0075] Select DN820 steel pipe, shot blast and remove rust from the steel pipe, then preheat with medium frequency, spray epoxy, and extrude 3PE anti-corrosion special material before the epoxy gels. The 3PE special material is extruded at 215℃, and the thickness of the anti-corrosion layer is controlled to be 3.0-3.5mm. The peel strength at 20, 60, and 80℃ is tested according to GB / T23257. The appearance of the 3PE anti-corrosion outer layer is shown in Table 5.

[0076] Comparative Example 2

[0077] The maleic anhydride grafted polyethylene (M2) is the same as in Example 2, and the raw materials used are the same as in Example 2.

[0078] The 3PE anti-corrosion special material of Comparative Example 2 is composed as shown in Table 4:

[0079] Table 4 3PE special material ratio in comparative example 2

[0080]

[0081] The specific steps for preparing 3PE anti-corrosion special materials are:

[0082] The components were mixed evenly in a mixer according to the proportion, added into a twin-screw extruder, melt-blended at 220° C. and 450 rpm, and granulated to obtain 3PE special anti-corrosion material.

[0083] Testing and application of 3PE anti-corrosion special materials:

[0084] The melt flow rate, yield strength, tensile strength, nominal strain at crack, Vicat softening point, oxidation induction time, and heat aging at 100°C for 4800h were tested in accordance with GB / T23257-2017. The relevant data are shown in Table 5.

[0085] Select DN820 steel pipe, shot blast and remove rust from the steel pipe, then preheat with medium frequency, spray epoxy, and extrude 3PE anti-corrosion special material before epoxy gel occurs. The 3PE special material is extruded at 225℃, and the thickness of the anti-corrosion layer is controlled to be 3.0-3.5mm. According to GB / T23257, the peel strength at 20, 60, and 80℃ is tested. The appearance of the 3PE anti-corrosion outer layer can be seen Figure 1 shown.

[0086] It can be seen from Examples 1 and 2 that the indicators of the prepared 3PE special material according to the configuration of the claims of the present application all meet the requirements of GB / T23257-2017, especially after the steel pipe is anti-corroded, it replaces the traditional three-layer anti-corrosion system of epoxy / adhesive / polyethylene special material, and the anti-corrosion layer has higher peeling strength: 20±5℃ temperature, ≥300N / cm; 60±5℃ temperature, ≥150N / cm; 80±5℃ temperature, ≥80N / cm.

[0087] From the comparison of 1A, 1B, 1C, 1D of Example 1 and Comparative Example 3A, it can be seen that adding 10-40 parts of maleic anhydride grafted polyethylene to the 3PE anti-corrosion special material can make the anti-corrosion special material have the function of an adhesive, achieve effective bonding to epoxy powder, and the peel strength of the anti-corrosion layer reaches: 20±5℃ temperature, ≥300N / cm; 60±5℃ temperature, ≥150N / cm; 80±5℃ temperature, ≥80N / cm. From the comparison of 1A and 3B, it can be seen that when the addition of maleic anhydride grafted polyethylene in the 3PE anti-corrosion special material is less than 10 parts, even if the peeling at 20℃ is qualified, the peeling strength at 60℃ and 80℃ is lower than the standard requirement. From the comparison of 1D, 3C and 3D, it can be seen that when the addition of maleic anhydride grafted polyethylene in the 3PE anti-corrosion special material is higher than 40 parts, the peel strength of the anti-corrosion base is not improved, especially the high-temperature peel strength becomes lower. This is mainly because the bonding strength is related to the cohesive strength of the maleic anhydride grafted polyethylene masterbatch and the original color. When the maleic anhydride reaches a certain proportion, the cohesive strength of the special material needs to be further improved to further improve the peel strength. Excessive addition of maleic anhydride grafted polyethylene reduces the proportion of high cohesive HDPE in the formula system, thereby causing the high-temperature peel strength of the polyethylene special material to decrease. It can be seen that the addition ratio of maleic anhydride grafted polyethylene is preferably 10-40 parts.

[0088] From the comparison of 2A, 2B, 2C and 4A in Example 2, it can be seen that adding 3-7 parts of elastomer to the 3PE special anti-corrosion material can improve the excellent mechanical properties and processing properties of the 3PE special anti-corrosion material. 4A without adding elastomer has unqualified tensile strength and nominal strain at break. From the comparison of 2C with 4C and 4D, it can be seen that when the elastomer in the 3PE special anti-corrosion material exceeds 10 parts, the yield strength of the special material will be lower than 15MPa and the Vicat softening point will be lower than 110°C, and the high temperature peel strength, especially the 80°C peel strength, will be reduced.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A 3PE anti-corrosion polyethylene special material with bonding and anti-corrosion functions, characterized in that: The invention comprises the following raw materials in parts by weight: 10-40 parts of maleic anhydride grafted polyethylene; High density polyethylene 20-50 parts; 20-40 parts of linear low density polyethylene; 3-10 parts of elastomer; Carbon black masterbatch 5-7 parts; Anti-aging additive 0.5-3 parts.

2. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The maleic anhydride grafted polyethylene is prepared by the following ratio and process: 90-100 parts of high-density polyethylene, 3-10 parts of propylene-based elastomer, 1-2 parts of maleic anhydride, and 0.02-0.2 parts of peroxide initiator; the grafting reaction is carried out at 200-300° C. through a twin-screw extruder, and the screw speed is 400-800rpm.

3. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The maleic anhydride grafted polyethylene is maleic anhydride grafted high-density polyethylene, the melt mass flow rate under the action of a 2.16 kg weight at 190° C. is 0.5-5 g / 10 min, and the maleic anhydride grafting rate is 0.5%-1.5%; The high-density polyethylene in the maleic anhydride grafted polyethylene has a melt mass flow rate of 2-10 g / min at 190° C. and under the action of a 2.16 kg weight; The high-density polyethylene described in the 3PE anti-corrosion polyethylene special material has a melt mass flow rate of 0.05-5g / 10min at 190°C and under the action of a 2.16kg weight.

4. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The linear low-density polyethylene has a melt mass flow rate of 0.5-20 g / min at 190° C. and under the action of a 2.16 kg weight; Preferably, the linear low-density polyethylene is a linear low-density polyethylene obtained by polymerization with a metallocene catalyst.

5. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The elastomer is at least one of ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer and hydrogenated styrene-butadiene-styrene block copolymer.

6. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The carbon black masterbatch contains 40% to 60% carbon black, and the particle size of the carbon black is less than 25nm.

7. The 3PE anti-corrosion polyethylene special material according to claim 1, characterized in that: The anti-aging auxiliary agent is one or more of hindered phenol antioxidants, sulfur-containing hindered phenol antioxidants, phosphite antioxidants, hindered amine light stabilizers and acid absorbers.

8. The method for preparing the 3PE anti-corrosion polyethylene special material according to any one of claims 1 to 7, characterized in that: include: Maleic anhydride grafted polyethylene, high-density polyethylene, linear low-density polyethylene, elastomer, carbon black masterbatch and anti-aging additive are mixed in proportion, and melt-blended and granulated by a screw extruder at 200-230° C. and a screw speed of 350-600 rpm to obtain a 3PE anti-corrosion special material.

9. Application of the 3PE anti-corrosion polyethylene special material according to any one of claims 1 to 7 in 3PE anti-corrosion of steel pipelines, characterized in that: According to the 3PE anti-corrosion process, the epoxy powder is sprayed and then the 3PE anti-corrosion polyethylene special material is wound to obtain a steel pipe anti-corrosion by epoxy and 3PE special materials.

10. An anti-corrosion steel pipe, characterized in that: It comprises a steel pipe, an epoxy anti-corrosion layer arranged in sequence from the inside to the outside of the steel pipe, and a 3PE anti-corrosion polyethylene special material layer as described in any one of claims 1 to 7.

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