Polypropylene composite materials and their preparation methods and applications, cables

Abstract

This application relates to a polypropylene composite material, its preparation method and application, and cables. By weight, the polypropylene composite material comprises the following components: 60-80 parts polypropylene, 20-40 parts ungrafted elastomer, 0.5-1.5 parts grafted elastomer, 0.01-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent; the hydrophilic agent includes at least one selected from ethylene-acrylic acid copolymer, polyvinyl butyral, polyacrylic acid, polyvinyl alcohol, and ethylene vinyl alcohol copolymer. The components in this polypropylene composite material interact with each other, effectively improving the water-tree resistance of the polypropylene composite material, while also exhibiting high tensile strength and elongation at break.

Description

Technical Field

[0001] This application relates to the field of materials, and in particular to a polypropylene composite material, its preparation method and application, and cables. Background Technology

[0002] Currently, cross-linked polyethylene (XLPE) is the most commonly used insulation material for plastic-insulated cables, and it is widely used in power distribution networks, industrial equipment, or other fields requiring high-capacity power. However, XLPE has disadvantages such as high energy consumption during production, complex processing technology, and non-recyclability. Developing green, environmentally friendly, and recyclable cable insulation materials is a development trend and an inevitable requirement of the power industry.

[0003] Polypropylene possesses advantages such as excellent electrical properties, high temperature resistance, simple processing technology, and recyclability after decommissioning, making it an important development direction for environmentally friendly cable insulation. Water treeing refers to the formation of microchannels within the insulation due to moisture, electrical stress, or inducing factors such as impurities, protrusions, space charges, and ions. In humid environments, water treeing is a cause of premature aging and failure in cables, and it can also easily lead to electrical treeing, causing cable insulation failure. However, traditional polypropylene materials have poor resistance to water treeing, resulting in cables that are prone to aging, failure, and have a short service life.

[0004] Therefore, it is necessary to improve traditional technologies. Summary of the Invention

[0005] Based on this, this application provides a polypropylene composite material with good water tree resistance, its preparation method and application, and a cable.

[0006] The technical solution to the above-mentioned technical problems in this application is as follows.

[0007] The first aspect of this application provides a polypropylene composite material, comprising the following components by mass parts:

[0008] The mixture comprises 60-80 parts of polypropylene, 20-40 parts of ungrafted elastomer, 0.5-1.5 parts of grafted elastomer, 0.01-0.2 parts of β-nucleating agent, and 3-6 parts of hydrophilic agent; wherein the hydrophilic agent includes at least one of ethylene-acrylic acid copolymer, polyvinyl butyral, polyacrylic acid, polyvinyl alcohol, and ethylene vinyl alcohol copolymer.

[0009] In some embodiments, the polypropylene composite material comprises, by mass parts:

[0010] 70-80 parts polypropylene, 20-30 parts ungrafted elastomer, 1-1.5 parts grafted elastomer, 0.01-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent.

[0011] In some embodiments, the mass ratio of the grafted elastomer to the ungrafted elastomer in the polypropylene composite material is (1.2-1.5):(20-25).

[0012] In some embodiments, the ungrafted elastomer in the polypropylene composite material satisfies at least one of the following characteristics (1) to (2):

[0013] (1) The ungrafted elastomer is a thermoplastic elastomer;

[0014] (2) The ungrafted elastomer includes at least one of ethylene propylene diene monomer (EPDM), ethylene vinyl acetate, styrene-ethylene-butene-styrene block copolymer, and polyolefin elastomer.

[0015] In some embodiments, the grafted elastomer in the polypropylene composite material satisfies at least one of the following characteristics (1) to (3):

[0016] (1) The grafted elastomer is a grafted thermoplastic elastomer;

[0017] (2) The grafted elastomer is grafted with at least one of maleic anhydride and glycidyl methacrylate;

[0018] (3) The grafted elastomer includes at least one of the following: polyolefin elastomer grafted with maleic anhydride, ethylene propylene diene monomer (EPDM) rubber grafted with maleic anhydride, ethylene-vinyl acetate copolymer grafted with maleic anhydride, styrene-ethylene-butene-styrene block copolymer grafted with maleic anhydride, and polyolefin elastomer grafted with glycidyl methacrylate.

[0019] In some embodiments, the β-nucleating agent in the polypropylene composite material includes at least one of acetal nucleating agents, amide nucleating agents, and rare earth nucleating agents.

[0020] In some embodiments, the polypropylene composite material contains polypropylene that satisfies at least one of the following characteristics (1) to (3):

[0021] (1) The polypropylene is isotactic polypropylene with an isotacticity ≥ 95%;

[0022] (2) The melt index of the polypropylene is 2.0 g / 10 min to 7.0 g / 10 min;

[0023] (3) The density of the polypropylene is 0.9 g / cm³. 3 ~0.95g / cm 3 .

[0024] A second aspect of this application provides a method for preparing a polypropylene composite material, comprising the following steps:

[0025] Raw materials are provided according to the composition of the polypropylene composite material provided in the first aspect;

[0026] A portion of the polypropylene and β-nucleating agent are mixed and then subjected to a first granulation to prepare polypropylene masterbatch;

[0027] The ungrafted elastomer, the grafted elastomer, and the hydrophilic agent are mixed and then subjected to a second granulation to prepare an elastomer masterbatch.

[0028] The polypropylene masterbatch, the elastomer masterbatch, the remaining polypropylene and the remaining ungrafted elastomer are mixed and molded to prepare a polypropylene composite material.

[0029] In some embodiments, the preparation method of the polypropylene composite material satisfies at least one of the following features (1) to (2):

[0030] (1) The mass percentage of the β-nucleating agent in the polypropylene masterbatch is 5% to 8%;

[0031] (2) The mass percentage of the hydrophilic agent in the elastomer masterbatch is 18% to 30%.

[0032] In some embodiments, in the preparation method of polypropylene composite material, the temperature of the first granulation is 180℃~220℃, the temperature of the second granulation is 180℃~200℃, and the temperature of the mixing is 180℃~200℃.

[0033] The third aspect of this application provides the application of the polypropylene composite material prepared by the preparation method of the polypropylene composite material provided in the first aspect or the polypropylene composite material provided in the second aspect in the preparation of polypropylene products.

[0034] The fourth aspect of this application provides a cable comprising a polypropylene composite material prepared by the method of preparing the polypropylene composite material provided in the first aspect or the method of preparing the polypropylene composite material provided in the second aspect.

[0035] Compared with the prior art, the polypropylene composite material of this application has the following beneficial effects:

[0036] The aforementioned polypropylene composite material includes polypropylene, ungrafted elastomer, grafted elastomer, β-nucleating agent, and hydrophilic agent. Using polypropylene as the matrix, the ungrafted elastomer and specific types of hydrophilic agents are uniformly distributed within the polypropylene under the action of the grafted elastomer and interact with it. This makes the crystals in the polypropylene composite material less prone to slippage under external forces, weakening the intercrystalline mobility and effectively inhibiting cracking at the crystal interface under the action of micro-water droplets. Furthermore, the uniform distribution of the ungrafted elastomer within the polypropylene forms a complex network with the crystalline and amorphous phases of the polypropylene, effectively extending the penetration path of water molecules in the polypropylene composite material and thus effectively inhibiting water molecule diffusion. The specific types of hydrophilic agents allow water molecules to disperse near the polar groups of the hydrophilic agent, effectively inhibiting water molecule accumulation. Simultaneously, the β-nucleating agent effectively enhances the crystallinity of the polypropylene composite material, refining the polypropylene grains and making the amorphous phase of the polypropylene composite material more dispersed. The interaction between the components effectively improves the water-tree resistance of the polypropylene composite material, while also exhibiting high tensile strength and elongation at break. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a diagram of the water tree morphology cultivated in the water tree aging test of the polypropylene composite material of Example 1. Detailed Implementation

[0039] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0040] Therefore, this invention is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the invention are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0042] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element preceded by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The indefinite articles “a” and “an” preceding an element or component of the invention are not restrictive in terms of the number of elements or components (i.e., the number of times they appear). Therefore, “an” or “an” should be interpreted as including one or at least one, and singular elements or components also include plural forms, unless the quantity clearly refers only to the singular. “A plurality” means at least two, such as two, three, etc., unless otherwise expressly specified.

[0043] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0044] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0045] One embodiment of this application provides a polypropylene composite material, comprising the following components by mass parts:

[0046] The composition includes 60-80 parts of polypropylene, 20-40 parts of ungrafted elastomer, 0.5-1.5 parts of grafted elastomer, 0.01-0.2 parts of β-nucleating agent, and 3-6 parts of hydrophilic agent; the hydrophilic agent includes at least one of ethylene-acrylic acid copolymer (EAA), polyvinyl butyral (PVB), polyacrylic acid (PAA), polyvinyl alcohol (PVA), and ethylene-vinyl alcohol copolymer (EVOH).

[0047] The aforementioned polypropylene composite material includes polypropylene, ungrafted elastomer, grafted elastomer, β-nucleating agent, and hydrophilic agent. Using polypropylene as the matrix, under the action of the grafted elastomer, specific types of hydrophilic agents and ungrafted elastomers are uniformly distributed within the polypropylene and interact with it. This makes the crystals in the polypropylene composite material less prone to slippage under external forces, weakening the intercrystalline mobility and effectively inhibiting cracking at the crystal interface under the action of micro-water droplets. Furthermore, the uniform distribution of ungrafted elastomers within the polypropylene forms a complex network with the crystalline and amorphous phases of the polypropylene, effectively extending the penetration path of water molecules in the polypropylene composite material and thus effectively inhibiting water molecule diffusion. The specific types of hydrophilic agents allow water molecules to disperse near the polar groups of the hydrophilic agents, effectively inhibiting water molecule accumulation. Simultaneously, under the action of the β-nucleating agent, the crystallinity of the polypropylene composite material is effectively enhanced, refining the polypropylene grains and making the amorphous phase of the polypropylene composite material looser. The interaction between the components effectively improves the water-tree resistance of the polypropylene composite material, while also exhibiting high tensile strength and elongation at break.

[0048] It is understood that, by weight, the polypropylene composite material contains, but is not limited to, 60, 62, 65, 68, 70, 72, 75, 78, and 80 parts of polypropylene. Ungrafted elastomers include, but are not limited to, 20, 22, 25, 28, 30, 32, 35, 38, and 40 parts. Grafted elastomers include, but are not limited to, 0.5, 0.6, 0.8, 1, 1.1, 1.2, 1.3, and 1.5 parts. β-nucleating agents include, but are not limited to, 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.16, 0.18, and 0.2 parts. Hydrophilic agents include, but are not limited to, 3.5, 4, 4.5, 5, 5.5, and 6 parts. In some examples, the range can be defined by any two of these point values ​​as endpoints, and the same applies below.

[0049] In some of these examples, the polypropylene composite material comprises, by mass parts, the following components:

[0050] 70-80 parts polypropylene, 20-30 parts ungrafted elastomer, 1-1.5 parts grafted elastomer, 0.01-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent.

[0051] In some of these examples, the polypropylene composite material comprises, by mass parts, the following components:

[0052] The composition includes 60-62 parts polypropylene, 38-40 parts ungrafted elastomer, 0.5-0.8 parts grafted elastomer, 0.01-0.05 parts β-nucleating agent, and 3-4 parts hydrophilic agent.

[0053] In some of these examples, the polypropylene composite material comprises, by mass parts, the following components:

[0054] The composition includes 68-72 parts polypropylene, 28-32 parts ungrafted elastomer, 1-1.2 parts grafted elastomer, 0.08-0.12 parts β-nucleating agent, and 3-6 parts hydrophilic agent.

[0055] In some of these examples, the polypropylene composite material comprises, by mass parts, the following components:

[0056] The composition includes 78-80 parts polypropylene, 18-20 parts ungrafted elastomer, 1.3-1.5 parts grafted elastomer, 0.18-0.2 parts β-nucleating agent, and 4-5 parts hydrophilic agent.

[0057] In some of these examples, the polypropylene composite material comprises, by mass parts, the following components:

[0058] The composition includes 68-72 parts polypropylene, 28-32 parts ungrafted elastomer, 1-1.2 parts grafted elastomer, 0.18-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent.

[0059] In some of these examples, the mass ratio of grafted elastomer to ungrafted elastomer in the polypropylene composite is (1.2–1.5):(20–25).

[0060] It is understood that the mass ratio of grafted elastomer to ungrafted elastomer includes, but is not limited to, 1.2:20, 1.2:21, 1.2:22, 1.2:23, 1.2:24, 1.2:25, 1.3:20, 1.3:21, 1.3:22, 1.3:23, 1.3:24, 1.3:25, 1.4:20, 1.4:21, 1.4:22, 1.4:23, 1.4:24, 1.4:25, 1.5:20, 1.5:21, 1.5:22, 1.5:23, 1.5:24, and 1.5:25.

[0061] In some of these examples, the ungrafted elastomer in the polypropylene composite is a thermoplastic elastomer.

[0062] In some of these examples, the ungrafted elastomer in the polypropylene composite includes at least one of ethylene propylene diene monomer (EPDM), ethylene vinyl acetate (EVA), styrene-ethylene-butene-styrene block copolymer (SEBS), and polyolefin elastomer (POE).

[0063] In some of these examples, the grafted elastomer in the polypropylene composite is a grafted thermoplastic elastomer.

[0064] In some of these examples, the grafted elastomer in the polypropylene composite is grafted with at least one of maleic anhydride and glycidyl methacrylate.

[0065] In some examples, the grafted elastomer in the polypropylene composite includes at least one of polyolefin elastomer grafted with maleic anhydride (POE-g-MAH), ethylene propylene diene monomer (EPDM) grafted with maleic anhydride (EPDM-g-MAH), ethylene-vinyl acetate copolymer grafted with maleic anhydride (EVA-g-MAH), styrene-ethylene-butene-styrene block copolymer grafted with maleic anhydride (SEBS-g-MAH), and polyolefin elastomer grafted with glycidyl methacrylate (POE-g-GMA).

[0066] In some specific examples, the hydrophilic agent in the polypropylene composite includes EAA, the ungrafted elastomer includes POE, and the grafted elastomer includes POE-g-MAH.

[0067] In some specific examples, the hydrophilic agent in the polypropylene composite includes PVB, the ungrafted elastomer includes SEBS, and the grafted elastomer includes SEBS-g-MAH.

[0068] In some specific examples, in polypropylene composites, the hydrophilic agent includes PVA, the ungrafted elastomer includes EPDM, and the grafted elastomer includes EPDM-MAH.

[0069] In some specific examples, the hydrophilic agent in the polypropylene composite includes EVOH, the ungrafted elastomer includes POE, and the grafted elastomer includes POE-g-GMA.

[0070] In some of these examples, the β-nucleating agent in the polypropylene composite material includes at least one of acetal nucleating agents, amide nucleating agents, and rare earth nucleating agents.

[0071] Furthermore, the acetal nucleating agent includes at least one of sorbitol nucleating agents and xylitol acetal nucleating agents. Even further, the sorbitol nucleating agent includes bis-1,3,2,4(4′-propylbenzylene)-1-propylsorbitol (TBPMN); the xylitol acetal nucleating agent includes DMDBX.

[0072] Furthermore, amide nucleating agents include aromatic diamide nucleating agents. Even further, aromatic diamide nucleating agents include at least one of 3,3',5,5'-tetramethylbenzidine (TMB-5) and N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide (DCNDCA).

[0073] Furthermore, rare earth nucleating agents include WBG-II.

[0074] In some of these examples, the polypropylene composite material contains isotactic polypropylene with an isotacticity ≥ 95%.

[0075] It is understandable that the methyl groups (-CH3) in the isotactic polypropylene molecular chain are distributed on one side of the main chain.

[0076] In some of these examples, the polypropylene composite has a melt index of 2.0 g / 10 min to 7.0 g / 10 min.

[0077] It is understood that the melt flow index of polypropylene includes, but is not limited to, 2.0 g / 10 min, 3.0 g / 10 min, 4.0 g / 10 min, 5.0 g / 10 min, 6.0 g / 10 min, and 7.0 g / 10 min.

[0078] In some of these examples, the polypropylene composite has a density of 0.9 g / cm³. 3 ~0.95g / cm 3 .

[0079] It is understood that the density of polypropylene includes, but is not limited to, 0.9 g / cm³. 3 0.91g / cm 3 0.92g / cm 3 0.93g / cm 3 0.94g / cm 3 0.95g / cm 3 .

[0080] In some of these examples, the polypropylene in the polypropylene composite is a copolymer polypropylene.

[0081] Furthermore, the copolymer polypropylene is a block copolymer polypropylene.

[0082] It is understandable that block copolymer polypropylene is obtained by copolymerizing propylene monomers and a small amount of ethylene monomers.

[0083] In some of these examples, in the polypropylene composites, the ethylene monomer in the block copolymer polypropylene accounts for 7%-15% of the total mass of propylene monomer and ethylene monomer.

[0084] One embodiment of this application provides a method for preparing a polypropylene composite material, comprising:

[0085] Step S10: Provide raw materials according to the composition of the polypropylene composite material described above.

[0086] In some of these examples, step S10 involves drying the raw materials.

[0087] In some examples, in step S10, the polypropylene and β-nucleating agent are vacuum dried at 65°C to 75°C. Further, the polypropylene and β-nucleating agent are vacuum dried at 70°C for 5 hours.

[0088] In some examples, in step S10, the ungrafted elastomer, the grafted elastomer, and the hydrophilic agent are vacuum dried at 45°C to 50°C. Further, the ungrafted elastomer, the grafted elastomer, and the hydrophilic agent are vacuum dried at 50°C for 5 hours.

[0089] Step S20: Mix a portion of polypropylene and β-nucleating agent and perform the first granulation to prepare polypropylene masterbatch.

[0090] In some of these examples, in step S20, the mass percentage of the β-nucleating agent is 5% to 8% of the mass percentage of the polypropylene masterbatch.

[0091] It is understood that the mass percentage of the β-nucleating agent in the polypropylene masterbatch includes, but is not limited to, 5%, 6%, 7%, and 8%.

[0092] In some of these examples, in step S20, the temperature of the first granulation is 180°C to 220°C.

[0093] It is understood that the temperature of the first granulation includes, but is not limited to, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, and 220℃.

[0094] In some of these examples, in step S20, a twin-screw extruder is used for mixing and extrusion, and a pelletizer is used for the first granulation.

[0095] In some of these examples, in step S20, the feed rate for the first granulation is set to 200 rpm to 300 rpm.

[0096] Step S30: Mix some ungrafted elastomer, grafted elastomer and hydrophilic agent and then perform a second granulation to prepare elastomer masterbatch.

[0097] In some of these examples, in step S30, the mass percentage of the hydrophilic agent is 18% to 30% of the mass of the elastomer masterbatch.

[0098] It is understood that the mass percentage of the hydrophilic agent in the elastomer masterbatch includes, but is not limited to, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and 30%.

[0099] In some of these examples, in step S30, the temperature of the second granulation is 180°C to 200°C.

[0100] It is understood that the temperature for the second granulation includes, but is not limited to, 180℃, 185℃, 190℃, 195℃, and 200℃.

[0101] In some of these examples, in step S30, a twin-screw extruder is used for mixing and extrusion, and a pelletizer is used for secondary granulation.

[0102] In some of these examples, in step S30, the feed rate for the second granulation is set to 200 rpm to 300 rpm.

[0103] Step S40: Mix the polypropylene masterbatch, elastomer masterbatch, remaining polypropylene and remaining ungrafted elastomer, and then mold them to prepare a polypropylene composite material.

[0104] In some of these examples, in step S40, the mixing temperature is 180°C to 220°C.

[0105] It is understood that the mixing temperature includes, but is not limited to, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, and 220℃.

[0106] It is understood that the molding methods include, but are not limited to, granulation, strip forming, or rod forming; correspondingly, the morphology of the obtained polypropylene composite material includes, but is not limited to, granules, strips, or rods.

[0107] In some of these examples, in step S40, a twin-screw extruder is used for mixing and extrusion, and a pelletizer is used for third granulation.

[0108] In some of these examples, in step S40, the feed rate for the third granulation is set to 200 rpm to 300 rpm.

[0109] In some specific examples, step S40 includes:

[0110] Step S41: Mix the polypropylene masterbatch with the remaining polypropylene to obtain a polypropylene mixture;

[0111] Step S42: The elastomer masterbatch is mixed with the remaining ungrafted elastomer to obtain an elastomer mixture;

[0112] Step S43: After mixing the polypropylene mixture and the elastomer mixture, perform a third granulation to prepare the polypropylene composite material.

[0113] In some examples, after the third granulation step, step S40 further includes drying the prepared material to obtain a polypropylene composite material. Optionally, vacuum drying is performed at 65°C to 75°C. Further, vacuum drying is performed at 70°C for 5 hours.

[0114] The above-mentioned method for preparing polypropylene composite material involves mixing polypropylene and a β-nucleating agent and then performing a first granulation to prepare polypropylene masterbatch. A portion of ungrafted elastomer, grafted elastomer, and a specific type of hydrophilic agent are mixed and then subjected to a second granulation to prepare elastomer masterbatch. Finally, the polypropylene masterbatch, elastomer masterbatch, and remaining components are kneaded to ensure that the ungrafted elastomer, β-nucleating agent, and hydrophilic agent are thoroughly and uniformly mixed with the polypropylene.

[0115] One embodiment of this application provides the application of the above-described polypropylene composite material or the polypropylene composite material prepared by the above-described preparation method in the preparation of polypropylene articles. Another embodiment of this application provides a polypropylene article comprising the above-described polypropylene composite material or the polypropylene composite material prepared by the above-described preparation method.

[0116] It is understood that polypropylene products include, but are not limited to, food packaging, cosmetic packaging, pharmaceutical packaging, automobile shells, dashboards, seats, medical supplies, infusion bottles, furniture, storage boxes, shoe boxes, cable conduits, and television shells.

[0117] One embodiment of this application provides a cable comprising the above-described polypropylene composite material or the polypropylene composite material prepared by the above-described preparation method.

[0118] It is understandable that polypropylene composite materials can be used to prepare cable insulation shells, which have good water tree resistance and can effectively extend the service life of cables.

[0119] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0120] The isotactic polypropylene used in the following examples and comparative examples has an isotacticity ≥95%, a melt index of 2.9 g / 10 min, and a density of 0.91 g / cm³. 3 .

[0121] Example 1

[0122] The components, by mass parts, are as follows:

[0123] 60 parts of isotactic polypropylene, 40 parts of ungrafted elastomer, 0.5 parts of grafted elastomer, 0.01 parts of β-nucleating agent, and 3 parts of hydrophilic agent;

[0124] (1) Polypropylene masterbatch was prepared by adding β nucleating agent (WBG-Ⅱ) to isotactic polypropylene, using a twin-screw extruder, mixing and extruding at 190°C, and then granulating with a pelletizer, wherein the mass ratio of β nucleating agent to isotactic polypropylene was 5:95.

[0125] (2) An elastomer masterbatch is prepared by mixing and extruding ungrafted elastomer (polyolefin elastomer POE), grafted elastomer (polyolefin elastomer grafted with maleic anhydride POE-g-MAH) and hydrophilic agent (ethylene-acrylic acid copolymer EAA) in a twin-screw extruder at 190°C, followed by granulation using a pelletizer; wherein the mass ratio of ungrafted elastomer, grafted elastomer and hydrophilic agent is 70:5:30.

[0126] (3) Mix the polypropylene masterbatch, elastomer masterbatch and the remaining polypropylene and the remaining ungrafted elastomer evenly, and then mix and extrude them at 190°C using a twin-screw extruder. Finally, granulate them using a pelletizer to produce polypropylene composite material.

[0127] Example 2

[0128] The components, by mass parts, are as follows:

[0129] The mixture contains 70 parts of isotactic polypropylene, 30 parts of ungrafted elastomer, 1 part of grafted elastomer, 0.1 parts of β-nucleating agent, and 6 parts of hydrophilic agent; wherein the mass ratio of ungrafted elastomer to grafted elastomer is 30:1.

[0130] (1) Polypropylene masterbatch was obtained by adding β nucleating agent (TMB-5) to isotactic polypropylene, using a twin-screw extruder, mixing and extruding at 200°C, and then granulating with a pelletizer, wherein the mass ratio of β nucleating agent to isotactic polypropylene was 5:95.

[0131] (2) An elastomer masterbatch is prepared by mixing and extruding ungrafted elastomer (styrene-ethylene-butene-styrene block copolymer SEBS), grafted elastomer (styrene-ethylene-butene-styrene block copolymer grafted with maleic anhydride SEBS-g-MAH) and hydrophilic agent (polyvinyl butyral PVB) in a twin-screw extruder at 180°C, followed by granulation using a pelletizer; wherein the mass ratio of ungrafted elastomer, grafted elastomer and hydrophilic agent is 70:5:30.

[0132] (3) Mix the polypropylene masterbatch, elastomer masterbatch and the remaining polypropylene and the remaining ungrafted elastomer evenly, and then mix and extrude them at 200°C using a twin-screw extruder. Finally, granulate them using a pelletizer to produce polypropylene composite material.

[0133] Example 3

[0134] The components, by mass parts, are as follows:

[0135] 80 parts of isotactic polypropylene, 20 parts of ungrafted elastomer, 1.5 parts of grafted elastomer, 0.2 parts of β-nucleating agent, and 4.5 parts of hydrophilic agent;

[0136] (1) Polypropylene masterbatch was prepared by adding β nucleating agent (TMB-5) to isotactic polypropylene, using a twin-screw extruder, mixing and extruding at 210°C, and then granulating with a pelletizer, wherein the mass ratio of β nucleating agent to isotactic polypropylene was 8:92.

[0137] (2) By mixing and extruding the ungrafted elastomer (EPDM), grafted elastomer (EPDM-MAH) and hydrophilic agent (PVA) in a twin-screw extruder at 195°C, and then granulating it using a pelletizer, an elastomer masterbatch is prepared; wherein the mass ratio of ungrafted elastomer, grafted elastomer and hydrophilic agent is 60:5:15.

[0138] (3) Mix the polypropylene masterbatch, elastomer masterbatch and the remaining polypropylene and the remaining ungrafted elastomer evenly, and then mix and extrude them at 210°C using a twin-screw extruder. Finally, granulate them using a pelletizer to produce polypropylene composite material.

[0139] Example 4

[0140] This is basically the same as Example 1, except that in Example 4, the hydrophilic agent (ethylene-acrylic acid copolymer EAA) in Example 1 is replaced with an equal mass of ethylene-vinyl alcohol copolymer EVOH.

[0141] Example 5

[0142] This is basically the same as Example 1, except that in Example 5, the hydrophilic agent (ethylene-acrylic acid copolymer EAA) in Example 1 is replaced with an equal mass of polyacrylic acid PAA.

[0143] Example 6

[0144] The example is basically the same as Example 1, except that in Example 6, the grafted elastomer (polyolefin elastomer grafted with maleic anhydride POE-g-MAH) in Example 1 is replaced with an equal mass of polyolefin elastomer grafted with glycidyl methacrylate POE-g-GMA.

[0145] Example 7

[0146] The composition is basically the same as in Example 1, except that in Example 7, the components are as follows by mass:

[0147] 70 parts isotactic polypropylene, 30 parts ungrafted elastomer, 1.2 parts grafted elastomer, 0.01 parts β nucleating agent, and 3 parts hydrophilic agent.

[0148] Example 8

[0149] The example is basically the same as Example 1, except that in Example 8, the components, by mass, are as follows:

[0150] 80 parts isotactic polypropylene, 20 parts ungrafted elastomer, 1.5 parts grafted elastomer, 0.01 parts β nucleating agent, and 3 parts hydrophilic agent.

[0151] Example 9

[0152] The example is basically the same as Example 1, except that in Example 9, the components, by mass parts, are as follows:

[0153] 60 parts isotactic polypropylene, 40 parts ungrafted elastomer, 0.5 parts grafted elastomer, 0.2 parts β nucleating agent, and 3 parts hydrophilic agent.

[0154] Comparative Example 1

[0155] The polypropylene material is a single-component isotactic polypropylene.

[0156] Comparative Example 2

[0157] Isotactic polypropylene and ungrafted elastomer (polyolefin elastomer POE) were mixed evenly at a mass ratio of 70:30, and then compounded and extruded using a twin-screw extruder at 200°C. Finally, the mixture was granulated using a pelletizer to obtain a polypropylene composite material.

[0158] Comparative Example 3

[0159] The polypropylene material is a block copolymer polypropylene, which is obtained by copolymerizing propylene monomer and ethylene monomer in a mass ratio of 85:15.

[0160] Comparative Example 4

[0161] The comparison example is basically the same as Example 1, except that the hydrophilic agent (ethylene-acrylic acid copolymer EAA) in Example 1 is replaced with an equal mass of polyethylene glycol in Comparative Example 4.

[0162] Comparative Example 5

[0163] The comparison is basically the same as Example 1, except that the grafted elastomer in Example 1 is omitted in Comparative Example 5, and the number of parts of ungrafted elastomer POE is 40.5 parts.

[0164] Comparative Example 6

[0165] The comparison is basically the same as in Example 1, except that in Comparative Example 6, the components, by mass parts, are as follows:

[0166] 80 parts of isotactic polypropylene, 20 parts of ungrafted elastomer, 3 parts of grafted elastomer, 0.01 parts of β-nucleating agent, and 3 parts of hydrophilic agent.

[0167] Comparative Example 7

[0168] It is basically the same as Example 1, except that no β nucleating agent is added to Comparative Example 7.

[0169] The main components of the polypropylene composites or polypropylene materials in each embodiment and comparative example are shown in Table 1.

[0170] Table 1

[0171]

[0172] The polypropylene composite materials or polypropylene materials in each embodiment and comparative example were pressed into sheets and cut into dumbbell-shaped specimens for tensile strength (GB / T1040.3-2006) and elongation at break (GB / T1040.3-2006). The polypropylene composite materials or polypropylene materials in each embodiment and comparative example were also pressed into sheets for water tree aging tests (GB / T21224-2007). The results are shown in Table 2. The water tree morphology of Example 1 after the water tree aging test is shown in the figure below. Figure 1 As shown.

[0173] Table 2

[0174]

[0175] Table 2 shows that, compared to the comparative examples, the water tree length of the polypropylene composites in each embodiment is significantly reduced, demonstrating that the polypropylene composites in each embodiment have better resistance to water treeing. Furthermore, the tensile strength and elongation at break of the polypropylene composites in each embodiment are also higher. Comparative Example 1 is a single-component isotactic polypropylene, Comparative Example 2 only added ungrafted elastomer to the isotactic polypropylene, and Comparative Example 3 is a block copolymer polypropylene obtained by copolymerizing propylene monomer and ethylene monomer in a mass ratio of 85:15. Comparative Examples 1-3 have poor mechanical properties, longer water tree lengths, and poor resistance to water treeing. Comparative Example 4 uses polyethylene glycol as a hydrophilic agent, which reduces its resistance to water treeing, indicating that specific types of hydrophilic agents need to be used in combination with other components to achieve better resistance. Water-tree resistance: Comparative Example 5, without grafted elastomer, showed poor compatibility among components, reduced tensile strength and elongation at break, and poor water-tree resistance. Comparative Example 6, with a higher mass fraction of grafted elastomer, reduced the content of β crystals, leading to a decrease in both tensile strength and elongation at break. Furthermore, the reduction in crystals also increased the amorphous phase within the material, thus decreasing its ability to inhibit water treeing. Adding a β nucleating agent refined the polypropylene composite grains, making the non-crystalline phase of the polypropylene composite looser and effectively improving its water-tree resistance. Comparative Example 7, without nucleating agent, showed a decrease in both tensile strength and elongation at break, and poor water-tree resistance.

[0176] The polypropylene composite material described in this application is of great significance for reducing water treeing in thermoplastic cables and extending the service life of the cables.

[0177] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0178] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A polypropylene composite material, characterized in that, By mass parts, it includes the following components: The composition comprises 60-80 parts polypropylene, 20-40 parts ungrafted elastomer, 0.5-1.5 parts grafted elastomer, 0.01-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent; wherein the hydrophilic agent is selected from at least one of ethylene-acrylic acid copolymer, polyvinyl butyral, polyacrylic acid, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer; wherein the ungrafted elastomer comprises at least one of ethylene propylene diene monomer (EPDM), styrene-ethylene-butene-styrene block copolymer, and polyolefin elastomer; and wherein the grafted elastomer comprises at least one of polyolefin elastomer grafted with maleic anhydride, EPDM grafted with maleic anhydride, styrene-ethylene-butene-styrene block copolymer grafted with maleic anhydride, and polyolefin elastomer grafted with glycidyl methacrylate.

2. The polypropylene composite material as described in claim 1, characterized in that, By mass parts, it includes the following components: 70-80 parts polypropylene, 20-30 parts ungrafted elastomer, 1-1.5 parts grafted elastomer, 0.01-0.2 parts β-nucleating agent, and 3-6 parts hydrophilic agent.

3. The polypropylene composite material as described in claim 1, characterized in that, The mass ratio of the grafted elastomer to the ungrafted elastomer is (1.2~1.5):(20~25).

4. The polypropylene composite material according to any one of claims 1 to 3, characterized in that, The β-nucleating agent includes at least one of acetal nucleating agents, amide nucleating agents, and rare earth nucleating agents.

5. The polypropylene composite material according to any one of claims 1 to 3, characterized in that, The polypropylene satisfies at least one of the following characteristics (1) to (3): (1) The polypropylene is isotactic polypropylene with an isotacticity ≥ 95%; (2) The melt index of the polypropylene is 2.0 g / 10min to 7.0 g / 10min; (3) The density of the polypropylene is 0.9 g / cm³. 3 ~0.95 g / cm 3 .

6. A method for preparing a polypropylene composite material, characterized in that, Includes the following steps: Raw materials are provided according to the components of the polypropylene composite material as described in any one of claims 1 to 5; A portion of the polypropylene and β-nucleating agent are mixed and then subjected to a first granulation to prepare polypropylene masterbatch; The ungrafted elastomer, the grafted elastomer, and the hydrophilic agent are mixed and then subjected to a second granulation to prepare an elastomer masterbatch. The polypropylene masterbatch, the elastomer masterbatch, the remaining polypropylene and the remaining ungrafted elastomer are mixed and molded to prepare a polypropylene composite material.

7. The preparation method according to claim 6, characterized in that, The preparation method satisfies at least one of the following features (1) to (2): (1) The mass percentage of the β-nucleating agent in the polypropylene masterbatch is 5% to 8%; (2) The mass percentage of the hydrophilic agent in the elastomer masterbatch is 18% to 30%.

8. The preparation method according to claim 6 or 7, characterized in that, The temperature of the first granulation is 180℃~220℃, the temperature of the second granulation is 180℃~200℃, and the temperature of the mixing is 180℃~220℃.

9. The use of the polypropylene composite material according to any one of claims 1 to 5 or the polypropylene composite material prepared by the preparation method according to any one of claims 6 to 8 in the preparation of polypropylene articles.

10. A cable, characterized in that, This includes the polypropylene composite material as described in any one of claims 1 to 5 or the polypropylene composite material prepared by the preparation method described in any one of claims 6 to 8.

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