Polyolefin composite material and preparation method therefor and use thereof

Abstract

The present application provides a polyolefin composite material and a preparation method therefor and a use thereof. In parts by weight, the polyolefin composite material comprises 20-50 parts of an ethylene-based polymer, 40-52 parts of an inorganic filler, 0.1-5 parts of a barrier agent, 0.2-1.8 parts of an epoxy resin, and 0.2-2 parts of an antioxidant. In the present application, the polyolefin composite material is resistant to additive precipitation and at the same time exhibits good thermal oxidative aging performance, enabling cables comprising the polyolefin composite material to be used in harsh environments and weather conditions.

Description

A polyolefin composite material, its preparation method and application Technical Field

[0001] This application relates to the field of polymer materials technology, such as a polyolefin composite material, its preparation method, and its application. Background Technology

[0002] Wires and cables, also known simply as cables, are wire products used to transmit electrical (magnetic) energy, information, and realize the conversion of electromagnetic energy. They are widely used in rail transit, transportation, communications, construction, energy, shipbuilding, automobiles, and other fields. With social development, the use of cables is increasing, not only indoors but also outdoors. When used outdoors, cables are affected by various harsh environments and weather conditions, such as high and low temperatures, strong ultraviolet radiation, high ozone concentrations, and chemical corrosion. Harsh environments and weather can lead to a decline in cable performance, and in severe cases, fires, endangering life and property.

[0003] To meet the requirements of cable materials used in harsh environments, the industry is actively developing high-efficiency heat and oxygen aging resistant cable materials. Typically, antioxidants are added to the formulation to improve the aging resistance of cable materials. However, with prolonged use, antioxidants and other additives can leach out, resulting in whitening and severe frosting on the material surface, affecting product use and, in the medium to long term, impacting its final weather resistance.

[0004] US Patent 5449711A discloses a method to prevent blooming on the surface of products molded from olefin thermoplastic elastomer compositions by incorporating one or more compounds selected from polyol esters and alkyl alkanolamines into an elastomer. However, while suppressing the precipitation of additives, the aforementioned patent does not take into account the aging resistance of the material.

[0005] Therefore, developing a cable material that combines resistance to exudation with good resistance to heat and oxygen aging is an urgent problem to be solved in this field. Summary of the Invention

[0006] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0007] This application provides a polyolefin composite material, its preparation method, and its application. The polyolefin composite material is resistant to additive precipitation and exhibits good thermo-oxidative aging properties, enabling cables comprising the polyolefin composite material to be used in harsh environments and weather conditions.

[0008] In a first aspect, this application provides a polyolefin composite material, which, by weight, comprises 20-50 parts of ethylene polymer, 40-52 parts of inorganic filler, 0.1-5 parts of barrier agent, 0.2-1.8 parts of epoxy resin and 0.2-2 parts of antioxidant.

[0009] In this application, by adding a barrier agent and using epoxy resin in combination with an antioxidant, the release of antioxidant can be reduced while improving oxygen shielding efficiency; at the same time, the addition of inorganic fillers can also reduce the release of additives and improve the oxygen shielding rate; thus enabling the polyolefin composite material to have both release resistance and thermo-oxidative aging resistance.

[0010] In this application, 20 to 50 parts of ethylene polymer can be, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts or any range of the above values; it can be selected as 25 to 45 parts.

[0011] In this application, the 40 to 52 parts of inorganic filler can be, for example, 40 parts, 40.2 parts, 40.5 parts, 40.8 parts, 41 parts, 41.2 parts, 41.5 parts, 41.8 parts, 42 parts, 42.2 parts, 42.5 parts, 42.8 parts, 43 parts, 43.2 parts, 43.5 parts, 43.8 parts, 44 parts, 44.2 parts, 44.5 parts, 44.8 parts, 45 parts, 45.2 parts, 45.5 parts, 45.8 parts, 46 parts, 46.2 parts, 46.5 parts, 46.8 parts, 47 parts, 47.2 parts, 47.5 parts, 47.8 parts, 48 ​​parts, 48.2 parts, 48.5 parts, 48.8 parts, 50 parts, 51 parts, 52 parts, or any range of the above values.

[0012] In this application, the amount of barrier agent is 0.1 to 5 parts, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, 3 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, 5 parts, or any range of the above values; it can be selected from 0.15 to 2 parts, and particularly from 0.2 to 1 part.

[0013] In this application, 0.2 to 1.8 parts of epoxy resin can be, for example, 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, 0.3 parts, 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, 0.4 parts, 0.42 parts, 0.44 parts, 0.46 parts, 0.48 parts, 0.5 parts, 0.52 parts, 0.54 parts, 0.56 parts, 0.58 parts, 0.6 parts, 0.62 parts, 0.64 parts, 0.6 parts, etc. 6 parts, 0.68 parts, 0.7 parts, 0.72 parts, 0.74 parts, 0.76 parts, 0.78 parts, 0.8 parts, 0.82 parts, 0.84 parts, 0.86 parts, 0.88 parts, 0.9 parts, 0.92 parts, 0.94 parts, 0.96 parts, 0.98 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or any range of the above values; 0.3 to 1.6 parts can be selected, and 0.55 to 1.45 parts are particularly optional.

[0014] In this application, 0.2 to 2 parts of antioxidant can be, for example, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, or any range of the above values.

[0015] In one embodiment, the ethylene polymer includes at least one of ethylene-vinyl acetate copolymer (EVA), linear low-density polyethylene (LLDPE), or polyolefin elastomer (POE).

[0016] In one embodiment, by weight, the ethylene polymer comprises 15 to 25 parts of ethylene-vinyl acetate copolymer (e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 parts or any of the above values), 1 to 10 parts of linear low-density polyethylene (e.g., 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 parts or any of the above values), and 4 to 15 parts of polyolefin elastomer (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 parts or any of the above values).

[0017] In this application, the ethylene-vinyl acetate copolymer (EVA) has a melt index of 0.3~10 g / 10min at 190°C and 2.16 kg, for example, it can be 0.3 g / 10min, 0.5 g / 10min, 1 g / 10min, 2 g / 10min, 3 g / 10min, 4 g / 10min, 5 g / 10min, 6 g / 10min, 7 g / 10min, 8 g / 10min, 9 g / 10min, 10 g / 10min or any range between the above values.

[0018] In this application, the linear low-density polyethylene (LLDPE) has a melt index of 1~10 g / 10min at 190℃ and 2.16 kg, for example, it can be 0.3 g / 10min, 0.5 g / 10min, 1 g / 10min, 2 g / 10min, 3 g / 10min, 4 g / 10min, 5 g / 10min, 6 g / 10min, 7 g / 10min, 8 g / 10min, 9 g / 10min, 10 g / 10min or any range between the above values.

[0019] In this application, the melt flow index test is performed according to the standard ASTM D1238-23; specifically, the plastic granules are first melted into a plastic fluid, and then, within a certain time (10 minutes), at a certain temperature and pressure (different standards for various materials), the fluid flows out through a 2.1 mm diameter circular tube, and its weight in grams (g) is measured. The higher the value, the better the processing fluidity of the material, and vice versa.

[0020] In this application, the polyolefin elastomer includes ethylene-butene copolymer and / or ethylene-octene copolymer; the polyolefin elastomer includes polyolefin elastomer prepared using a metallocene catalyst.

[0021] In this application, the melt index of the polyolefin elastomer at 190°C and 2.16 kg is 0.3~20 g / 10min, for example, it can be 0.3 g / 10min, 0.5 g / 10min, 1 g / 10min, 2 g / 10min, 3 g / 10min, 4 g / 10min, 5 g / 10min, 6 g / 10min, 7 g / 10min, 8 g / 10min, 10 g / 10min, 12 g / 10min, 14 g / 10min, 16 g / 10min, 18 g / 10min, 20 g / 10min or any range between the above values.

[0022] In one embodiment, the surface of the inorganic filler is coated with at least one of an amine compound, a silane, or stearic acid.

[0023] In one embodiment, the amine compound includes quaternary ammonium salts and / or amide compounds.

[0024] In one embodiment, the silane includes at least one of vinylsilane, aminosilane, epoxysilane, or polysilicone.

[0025] In one embodiment, the inorganic filler comprises aluminum hydroxide and / or magnesium hydroxide.

[0026] In this application, the D50 particle size of the inorganic filler is 0.5~5μm, for example, it can be 0.5μm, 0.6μm, 0.8μm, 1μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 2μm, 2.2μm, 2.4μm, 2.6μm, 2.8μm, 3μm, 3.2μm, 3.4μm, 3.6μm, 3.8μm, 4μm, 4.2μm, 4.4μm, 4.6μm, 4.8μm, 5μm or any of the above values.

[0027] In this application, the inorganic filler can be modified at the interface by coating the surface of the inorganic filler with amine compounds, silanes or stearic acid, which helps to improve the compatibility between the inorganic filler and the matrix resin, reduce the channels for the precipitation of additives, and improve the oxygen shielding rate, thereby taking into account both the precipitation resistance and the heat and oxygen aging resistance of the polyolefin composite material.

[0028] In one embodiment, the barrier agent comprises an inorganic material having a layered structure.

[0029] In one embodiment, the barrier agent includes at least one of intercalated montmorillonite, hydrotalcite, talc powder, or kaolin.

[0030] In one embodiment, the D50 particle size of the barrier agent is 0.05~0.3μm, for example, it can be 0.05μm, 0.06μm, 0.07μm, 0.08μm, 0.09μm, 0.1μm, 0.11μm, 0.12μm, 0.13μm, 0.14μm, 0.15μm, 0.16μm, 0.17μm, 0.18μm, 0.19μm, etc. The D50 particle size can be 0.121 to 0.201 μm, or more specifically, 0.125 to 0.142 μm.

[0031] In one embodiment, the epoxy resin comprises a grafted epoxy resin containing carbon-carbon double bond ester compounds.

[0032] In one embodiment, the carbon-carbon double bond ester compound includes vinyl acetate and / or ethyl acrylate.

[0033] In one embodiment, the grafting rate of the carbon-carbon double bond ester compound grafted epoxy resin is 0.5% to 2.5%, for example, it can be 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, or any range of the above values, and further optionally, the grafting rate is 1% to 2%.

[0034] In one embodiment, the epoxy resin comprises vinyl acetate-grafted epoxy resin and / or ethyl acrylate-grafted epoxy resin.

[0035] In one embodiment, the mass ratio of the antioxidant, barrier agent, and epoxy resin is 1:(0.1~2):(0.2~2.5), wherein the specific value of (0.1~2) can be, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.33, 0.35, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.72, 0.74, 0.75, 0.78, 0.8, 0.85, 0.9, 0.95, 1, 1.1, 1.2, 1.4, 1.6, 1.8, 2, or any range between the above values; The specific values ​​in (0.2~2.5) can be, for example, 0.2, 0.3, 0.4, 0.5, 0.6, 0.67, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5 or any range of the above values; further, the mass ratio of antioxidant, barrier agent and epoxy resin can be selected as 1:(0.3~1):(0.6~1.6).

[0036] In one embodiment, the antioxidant includes at least one of hindered phenolic antioxidants, thioester antioxidants, or phosphite antioxidants.

[0037] In one embodiment, the antioxidant comprises a compound antioxidant consisting of a hindered phenolic antioxidant as the main antioxidant and a thioester antioxidant and / or a phosphite antioxidant as the auxiliary antioxidant; the mass ratio of the main antioxidant to the auxiliary antioxidant is (1~3):1, wherein the specific values ​​of (1~3) can be, for example, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3 or any range of the above values.

[0038] In one embodiment, the polyolefin composite material further includes 2 to 16 parts by weight of other additives, for example, 2 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts or any range of the above values.

[0039] In one embodiment, the other additives include at least one of a compatibilizer, a dispersant, or a colorant.

[0040] In one embodiment, the compatibilizer comprises maleic anhydride-grafted modified metallocene polyethylene.

[0041] In this application, the melt index of the maleic anhydride-grafted modified metallocene polyethylene at 190°C and 2.16 kg is 0.5~4 g / 10min, for example, it can be 0.5 g / 10min, 1 g / 10min, 2 g / 10min, 3 g / 10min, 4 g / 10min or any range between the above values.

[0042] In one embodiment, the dispersant comprises an organosiloxane polymer.

[0043] In this application, the organosiloxane polymer includes an ultra-high molecular weight organosiloxane polymer, wherein the mass percentage of siloxane in the ultra-high molecular weight organosiloxane polymer is 40-60%, for example, it can be 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60% or any of the above values; the ultra-high molecular weight refers to a weight average molecular weight of 1 million to 1.5 million.

[0044] In one embodiment, the colorant comprises carbon black.

[0045] In this application, the carbon black exists in the form of carbon black masterbatch, wherein the mass percentage of carbon black in the carbon black masterbatch is ≥48%, for example, it can be 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80% or any range between the above values; the carbon black dispersion in the carbon black masterbatch is ≤3 grade; the resin matrix of the carbon black masterbatch includes polyolefin.

[0046] In one embodiment, the polyolefin composite material comprises, by weight, 1 to 6 parts of compatibilizer (e.g., 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.5 parts, 6 parts, or any range between the above values), and 1 to 6 parts of dispersant (e.g., 1 part, 1.2 parts, 1.4 parts, 1 part ... 0.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.5 parts, 6 parts or any range of the above values) and 0.5 to 3 parts of carbon black (for example, it can be 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.7 parts, 3 parts or any range of the above values).

[0047] In this application, lubricants, acid absorbers, etc. may also be added as needed; the lubricants include erucamide, ethylene bis-stearamide, ethylene wax or white oil, etc.; the acid absorbers include magnesium hydroxide, zinc oxide, zinc stearate, etc.

[0048] Secondly, this application provides a method for preparing the polyolefin composite material described in the first aspect, the method comprising the following steps:

[0049] The polyolefin composite material is obtained by mixing ethylene polymers, inorganic fillers, barrier agents, epoxy resins and antioxidants and then extruding the mixture.

[0050] In one embodiment, the mixed material also includes other additives.

[0051] In this application, the mixing includes: adding ethylene polymers, inorganic fillers, epoxy resins, and optional compatibilizers and dispersants into a high-speed mixer and mixing them evenly at a speed of 2000~3000 rpm; adding optional lubricants and mixing at a speed of 1000~3000 rpm for 1~3 minutes; and then adding antioxidants, barrier agents, carbon black masterbatches, and optional acid scavengers and mixing them evenly in a high-speed mixer at a speed of 500~1500 rpm.

[0052] In one embodiment, the extrusion temperature is 180~220°C, for example, it can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C or any range between the above values.

[0053] In this application, the extrusion is carried out in a twin-screw extruder; the length-to-diameter ratio of the twin-screw extruder is 44~50:1; and the temperature of each zone of the twin-screw extruder is 180~220℃.

[0054] Thirdly, this application provides a cable comprising the polyolefin composite material described in the first aspect.

[0055] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0056] Compared with related technologies, the beneficial effects of this application are as follows:

[0057] The polyolefin composite material provided in this application, by adding a barrier agent and epoxy resin in combination with an antioxidant, can reduce the release of antioxidants and improve oxygen shielding efficiency. At the same time, the addition of inorganic fillers can also reduce the release of additives and improve the oxygen shielding rate. Thus, the polyolefin composite material has both release resistance and thermo-oxidative aging resistance.

[0058] After reading and understanding the detailed description, other aspects can be understood. Detailed Implementation

[0059] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0060] All materials used in this application can be obtained by commercially available or conventional preparation methods. Unless otherwise specified, the materials used in this application are as follows:

[0061] Ethylene polymers

[0062] EVA: EVA V5120J, Jiangsu Sirbang Petrochemical Co., Ltd.

[0063] LLDPE: LLDPE DFDA-7042, Wanhua Chemical.

[0064] POE: SOLUMER 891, SK Korea.

[0065] Inorganic packing

[0066] A1: Aminosilane modified aluminum hydroxide, Aitemina 140FF, Jiangsu Aiteke Flame Retardant Materials Co., Ltd.

[0067] A2: Silane-modified aluminum hydroxide, Aitemina 140FD, Jiangsu Aiteke Flame Retardant Materials Co., Ltd.

[0068] A3: Stearic acid modified aluminum hydroxide, Aitamina 140ZA, Jiangsu Aitam Flame Retardant Materials Co., Ltd.

[0069] A4: Aminosilane-modified magnesium hydroxide, H-5IV, Albemarle, USA.

[0070] A5: Unmodified aluminum hydroxide, Aitumina 140, Jiangsu Aitumia Flame Retardant Materials Co., Ltd.

[0071] Barrier

[0072] B1: Hydrotalcite, D50 particle size is 0.128μm, AZ-128 Chenghe Technology.

[0073] B2: Hydrotalcite, D50 particle size is 0.137μm, AC-106, Chenghe Technology.

[0074] B3: Hydrotalcite, D50 particle size is 0.1μm, ground AZ-128, Chenghe Technology.

[0075] B4: Hydrotalcite, D50 particle size is 0.208μm, AC-390, Chenghe Technology.

[0076] B5: Montmorillonite, D50 particle size 0.128μm, I.44P (16~20μm) after grinding, Nanocor Inc.

[0077] B6: Talc powder, D50 particle size is 0.128μm, ground TYT-777A, Beihai Group.

[0078] In this application, the particle size of the barrier agent can be tested using a laser particle size analyzer.

[0079] Epoxy resin

[0080] C1: Vinyl acetate grafted epoxy resin, grafting rate 1.2%, self-made.

[0081] The preparation method of C1 includes: adding 200g of bisphenol A type epoxy resin (YD-019, purchased from Dongdu Chemical) to a four-necked flask, adding 1 / 3 of the prepared vinyl acetate xylene solution (the mass fraction of vinyl acetate in the vinyl acetate xylene solution is 40%, of which xylene is 38g and vinyl acetate is 25.3g), and then adding 0.3% initiator BPO (based on the weight of epoxy resin). Stirring is started to mix the materials thoroughly. Under nitrogen protection, the mixture is heated to 80°C and kept at this temperature for 30 minutes. Then, the remaining vinyl acetate xylene solution is added dropwise uniformly, and the addition is completed within 1.5 hours. After the monomer is added, the mixture is kept at 80°C for another 3 hours and then cooled to room temperature. Xylene solution is added again, and the mixture is sealed and stored. The xylene is removed by concentration using a rotary evaporator under room temperature vacuum (vacuum degree is 0.09MPa) to obtain the vinyl acetate grafted epoxy resin C1.

[0082] In this application, the method for determining the grafting rate includes: firstly, dissolving the grafted epoxy resin in xylene, refluxing for 1 hour, then adding excess acetone to precipitate, allowing it to stand for a period of time until precipitation is complete, repeatedly adding acetone and filtering the precipitate several times, then drying it in a vacuum oven at 70°C for 2 hours for later use; accurately weighing 0.15g of purified grafted epoxy resin, placing it in 100mL of xylene, adding 2-3 drops of deionized water and 2-3 drops of DMF to promote the hydrolysis of ester groups to generate carboxylic acid groups, refluxing for 1 hour, and titrating with 0.05mol / L KOH-ethanol standard solution (prepared according to GB / T601-2002 method), using phenolphthalein-ethanol solution as an indicator, and using a blank experiment without the addition of grafted epoxy resin. The grafting rate is calculated according to the following formula:

[0083] ω%=100%×(V1-V0) ×C×M / W.

[0084] In the formula: ω% is the grafting rate of the grafted epoxy resin.

[0085] V0: Volume of KOH-ethanol standard solution consumed by the blank sample.

[0086] V1: Volume of KOH-ethanol standard solution consumed by the grafted epoxy resin sample.

[0087] C: Molar concentration of KOH-ethanol standard solution, mol / L.

[0088] M: Vinyl acetate molecular weight 86.09 or ethyl acrylate molecular weight 100.12.

[0089] W: Quality of vinyl acetate-grafted epoxy resin or quality of ethyl acrylate-grafted epoxy resin.

[0090] C2: Vinyl acetate grafted epoxy resin, grafting rate 1.8%, self-made.

[0091] The preparation method of C2 differs from that of C1 only in that the mass fraction of vinyl acetate in the xylene solution of vinyl acetate is changed to 45%, of which xylene is 38g and vinyl acetate is 31g. The rest are the same as the preparation method of C1.

[0092] C3: Vinyl acetate-grafted epoxy resin, grafting rate 0.6%, self-made.

[0093] The preparation method of C3 differs from that of C1 only in that the mass fraction of vinyl acetate in the xylene solution of vinyl acetate is changed to 30%, of which xylene is 38g, vinyl acetate is 16.3g, and the content of initiator BPO is changed to 0.2%. All other preparation methods are the same as those of C1.

[0094] C4: Vinyl acetate grafted epoxy resin, grafting rate 2.3%, self-made.

[0095] The preparation method of C4 differs from that of C1 only in that the mass fraction of vinyl acetate in the xylene solution of vinyl acetate is changed to 48%, with 38g of xylene and 36g of vinyl acetate, and the content of initiator BPO is changed to 0.35%. All other preparation methods are the same as those of C1.

[0096] C5: Ethyl acrylate grafted epoxy resin, grafting rate 1.2%, self-made.

[0097] The only difference between the preparation method of C5 and C1 is that vinyl acetate is replaced with ethyl acrylate, and the mass fraction of ethyl acrylate in the xylene solution of ethyl acrylate is 40%, of which xylene is 38g and ethyl acrylate is 25.3g. The rest are the same as the preparation method of C1.

[0098] C6: Bisphenol A type epoxy resin, YD-019, Dongdu Chemical.

[0099] Poly(methylene adipate) phthalamide (MXD6): M30, purchased from Shanghai Yinggu Co., Ltd.

[0100] Antioxidant: A compound antioxidant composed of hindered phenolic antioxidant and thioester antioxidant in a mass ratio of 2:1; the hindered phenolic antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010); the thioester antioxidant is lauryl thiodipropionate.

[0101] Compatibilizer: Maleic anhydride-grafted modified metallocene polyethylene, MC218, Ningbo Nengzhiguang New Material Technology Co., Ltd.

[0102] Dispersant: Ultra-high molecular weight organosiloxane polymer, wherein the siloxane content is 55% by mass, GT-300, Zhejiang Jiahua Essence.

[0103] Carbon black masterbatch: The matrix resin is PE; the carbon black mass percentage is 50% and the carbon black dispersion grade is ≤3.

[0104] Examples 1-21, Comparative Examples 1-6

[0105] Examples 1-21 and Comparative Examples 1-6 each provide a polyolefin composite material. The formulations of the polyolefin composite materials are shown in Tables 1-4 by weight. Wherein, " / " indicates that the component is not in the formulation; antioxidant:barrier:epoxy resin indicates the mass ratio of the three; carbon black content refers to the weight of pure carbon black, excluding the matrix resin in the masterbatch.

[0106] The preparation method of the polyolefin composite material includes: adding LLDPE, POE, EVA, epoxy resin, inorganic filler, compatibilizer, and dispersant into a high-speed mixer in proportion and mixing them evenly at a speed of 2500 rpm; adding lubricant 10# white oil and mixing at a speed of 2000 rpm for 2 minutes; then adding antioxidant, barrier agent, and carbon black masterbatch and mixing them evenly in the high-speed mixer at a speed of 1000 rpm; extruding the resulting mixture through a twin-screw extruder and granulating it; the length-to-diameter ratio (L / D) of the twin-screw extruder is 48:1, and the temperature of each zone is 180-200℃. Specifically, T1 is 180℃, T2-T7 are all 200℃, and T8 is 180℃.

[0107]

[0108]

[0109]

[0110]

[0111] Performance testing

[0112] The polyolefin composite material particles provided in Examples 1-21 and Comparative Examples 1-4 were hot-pressed into sheets with a thickness of 1 mm and tested as follows; wherein, when testing tensile strength and elongation at break, the sheets were cut into dumbbell shapes for testing.

[0113] (1) Initial tensile strength and initial elongation at break: determined according to the method of standard GB / T 1040.3-2018.

[0114] (2) Heat and oxygen aging resistance: The polyolefin composite material was aged in air at 180°C for 168 h. The tensile strength and elongation at break of the polyolefin composite material after aging were tested according to standard GB / T 1040.3-2018. The tensile strength retention rate and elongation at break retention rate were calculated. Retention rate = tensile strength after aging (elongation at break after aging) / initial tensile strength (initial elongation at break). The higher the retention rate, the better the heat and oxygen aging resistance.

[0115] (3) Resistance to precipitation: The polyolefin composite material was placed at a temperature of 85℃ and a humidity of 85% for 1000h, and the presence of additives on the material surface was observed. Among them, no additives were precipitated as 0, the amount of precipitated additives accounting for less than 1% of the total material area was 1, the amount of precipitated additives accounting for 1~5% of the total material area was 2, and the amount of precipitated additives accounting for 5% or more of the total material area was 3.

[0116] The specific test results are shown in Table 5.

[0117]

[0118] As shown in Table 5, the polyolefin composite material provided in this application, with the addition of epoxy resin and barrier agent, possesses both heat oxidation resistance and precipitation resistance. The tensile strength of the polyolefin composite material is ≥13MPa, and the elongation at break is ≥370%; after heat and oxygen aging, the tensile strength retention rate is ≥72%, and the elongation at break retention rate is ≥70%.

[0119] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A polyolefin composite material, wherein, By weight, the polyolefin composite material comprises 20-50 parts of ethylene polymer, 40-52 parts of inorganic filler, 0.1-5 parts of barrier agent, 0.2-1.8 parts of epoxy resin and 0.2-2 parts of antioxidant.

2. The polyolefin composite material according to claim 1, wherein, The ethylene polymers include at least one of ethylene-vinyl acetate copolymer, linear low-density polyethylene, or polyolefin elastomer.

3. The polyolefin composite material according to claim 2, wherein, By weight, the ethylene polymer comprises 15-25 parts of ethylene-vinyl acetate copolymer, 1-10 parts of linear low-density polyethylene, and 4-15 parts of polyolefin elastomer.

4. The polyolefin composite material according to any one of claims 1-3, wherein, The surface of the inorganic filler is coated with at least one of amine compounds, silanes, or stearic acid.

5. The polyolefin composite material according to claim 4, wherein, The amine compounds include quaternary ammonium salts and / or amide compounds; Optionally, the silane includes at least one of vinylsilane, aminosilane, epoxysilane, or polysilicone.

6. The polyolefin composite material according to any one of claims 1-5, wherein, The inorganic filler includes aluminum hydroxide and / or magnesium hydroxide.

7. The polyolefin composite material according to any one of claims 1-6, wherein, The barrier agent comprises an inorganic material having a layered structure; Optionally, the barrier agent includes at least one of intercalated montmorillonite, hydrotalcite, talc powder, or kaolin. Optionally, the D50 particle size of the barrier agent is 0.05~0.3μm, and more preferably, the D50 particle size is 0.121~0.201μm.

8. The polyolefin composite material according to any one of claims 1-7, wherein, The epoxy resin includes epoxy resin grafted with carbon-carbon double bond ester compounds; Optionally, the carbon-carbon double bond-containing ester compound includes vinyl acetate and / or ethyl acrylate; Optionally, the grafting rate of the epoxy resin grafted with the carbon-carbon double bond ester compound is 0.5-2.5%, and more preferably 1-2%. Optionally, the epoxy resin includes vinyl acetate-grafted epoxy resin and / or ethyl acrylate-grafted epoxy resin.

9. The polyolefin composite material according to any one of claims 1-8, wherein, The mass ratio of the antioxidant, barrier agent and epoxy resin is 1:(0.1~2):(0.2~2.5), and it is further optional that the mass ratio of the antioxidant, barrier agent and epoxy resin is 1:(0.3~1):(0.6~1.6). Optionally, the antioxidant includes at least one of hindered phenolic antioxidants, thioester antioxidants, or phosphite antioxidants.

10. The polyolefin composite material according to any one of claims 1-9, wherein, The polyolefin composite material also includes 2 to 16 parts of other additives by weight.

11. The polyolefin composite material according to claim 10, wherein, The other additives include at least one of compatibilizers, dispersants, or colorants.

12. The polyolefin composite material according to claim 11, wherein, The compatibilizer includes maleic anhydride-grafted modified metallocene polyethylene. Optionally, the dispersant comprises an organosiloxane polymer; Optionally, the colorant includes carbon black; Optionally, the polyolefin composite material comprises, by weight, 1 to 6 parts compatibilizer, 1 to 6 parts dispersant and 0.5 to 3 parts carbon black.

13. A method for preparing a polyolefin composite material according to any one of claims 1-12, comprising the following steps: The polyolefin composite material is obtained by mixing ethylene polymers, inorganic fillers, barrier agents, epoxy resins and antioxidants and then extruding the mixture.

14. The preparation method according to claim 13, wherein, The mixed materials also include other additives; Optionally, the extrusion temperature is 180~220℃.

15. A cable, wherein, The cable comprises the polyolefin composite material according to any one of claims 1-12.

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