High-strength high-impact polypropylene / metal composite material, its preparation and use

Abstract

This invention relates to the field of polypropylene materials, and discloses a high-strength, high-impact polypropylene / metal composite material, its preparation method, and its applications. The polypropylene / metal composite material has a layered structure, including at least one metal material layer and multiple corresponding polypropylene coating layers covering each metal material layer. The metal material layer has multiple through-holes. Each polypropylene coating layer includes at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from the polypropylene sheet. The polypropylene sheet includes layer A and layers B and B' located on either side of layer A, with a structure of BAB'. The melting point of polypropylene composition A is greater than that of polypropylene composition B and polypropylene composition B'. The polypropylene / metal composite material of this invention simultaneously possesses excellent tensile and impact resistance properties, and still exhibits good interlaminar peel strength even when prepared at relatively low hot-pressing temperatures.

Description

Technical Field

[0001] This invention relates to the field of polyolefin / metal composites, and more specifically, to a high-strength, high-impact polypropylene / metal composite material, its preparation method, and its applications. Background Technology

[0002] Polymer / metal composites are characterized by high strength-to-weight ratio, impact resistance, and corrosion resistance, and are widely used in the automotive manufacturing, sporting goods manufacturing, electrical appliance manufacturing, and military fields.

[0003] Due to the significant differences in physical and chemical properties between polymers and metals, the adhesion of polymers to metals, especially non-polar polyolefin polymers, is challenging. Traditional techniques for preparing polymer / metal composites include activated metal surface polymerization, insert injection molding, 3D printing, mechanical fastening, and adhesive bonding. For example, CN 114096618A proposes improving the adhesion between polyamide and metal by treating the metal surface with a solution of triazine thiol derivatives, and preparing polyamide / metal composites through insert injection molding, co-extrusion, or powder coating. CN 112974853A discloses a method for preparing metal-polymer composites by filling plastic powder into directly formed 3D-printed metal cavities.

[0004] Traditional polymer / metal composite material preparation technologies have drawbacks such as high energy consumption, complex processes, and release of volatile pollutants. Furthermore, traditional preparation technologies are not always applicable to non-polar polyolefins. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-strength, high-impact polypropylene / metal composite material, its preparation method, and its applications. This invention obtains the polypropylene / metal composite material by hot-pressing laminated polypropylene sheets and a metal material layer (preferably a metal mesh), offering advantages such as simple molding process, safety, and environmental friendliness. This polypropylene / metal composite material exhibits excellent mechanical properties and good interlaminar peel strength, maintaining high interlaminar peel strength even at lower hot-pressing temperatures and over a wide hot-pressing temperature range.

[0006] The first aspect of the present invention is to provide a polypropylene / metal composite material having a laminated structure, comprising at least one metal material layer and a plurality of corresponding polypropylene covering layers on each metal material layer, wherein the metal material layer has a plurality of through holes distributed thereon; each polypropylene covering layer may be the same or different, and each comprises at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from the polypropylene sheet; wherein the polypropylene sheet comprises layer A and layers B and B' located on both sides of layer A, having a structure of BAB';

[0007] Layer A contains a polypropylene composition A, which includes homopolymer polypropylene a and impact copolymer polypropylene b; Layer B may be the same as or different from Layer B', and each contains a polypropylene composition B and a polypropylene composition B', wherein each of the polypropylene compositions B and B' includes random copolymer polypropylene x and a thermal bonding reinforcing agent y; wherein the melting point of the polypropylene composition A is greater than the melting points of the polypropylene compositions B and B', preferably the difference between the melting points of polypropylene compositions A and B, and the difference between the melting points of polypropylene compositions A and B', is greater than or equal to 5°C, preferably greater than or equal to 10°C, and more preferably greater than or equal to 20°C.

[0008] In a preferred embodiment of the present invention, the polypropylene fabric has a three-dimensional structure of plain weave, twill weave, and / or satin weave.

[0009] According to the present invention, the thin film layers B and B' on both sides of the thin film layer A may be the same or different. In a preferred embodiment of the present invention, the thin film layers B and B' on both sides of the thin film layer A are the same.

[0010] The present invention does not limit the thickness of the polypropylene sheet, and it can be selected within a wide range according to its actual application field. Preferably, the thickness of the polypropylene sheet can be 10-1000μm, more preferably 30-500μm, and even more preferably 50-300μm.

[0011] According to the present invention, the thickness of film layers A, B, and B' can be controlled by the extruder melt pump during the processing.

[0012] In a preferred embodiment of the present invention, based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 50-99 wt% homopolymer polypropylene a and 1-50 wt% impact copolymer polypropylene b; preferably, the polypropylene composition A comprises 70-90 wt% homopolymer polypropylene a and 10-30 wt% impact copolymer polypropylene b.

[0013] In a preferred embodiment of the present invention, based on the total weight of each of the polypropylene compositions B and B', each of the polypropylene compositions B and B' comprises 70-99 wt% random copolymer polypropylene x and 1-30 wt% thermal bonding reinforcing agent y; preferably, each of the polypropylene compositions B and B' comprises 80-90 wt% random copolymer polypropylene x and 10-20 wt% thermal bonding reinforcing agent y.

[0014] In a preferred embodiment of the present invention, based on the total thickness of the polypropylene sheet, the thickness of the film layer A accounts for 51%-89% of the total thickness, preferably 71%-89%, and more preferably 71%-80%.

[0015] In a preferred embodiment of the present invention, the melting point of the polypropylene composition A is greater than the melting points of the polypropylene compositions B and B'.

[0016] In a preferred embodiment of the present invention, the melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in each of the polypropylene compositions B and B', and preferably the temperature difference between the corresponding melting points is greater than or equal to 10 degrees.

[0017] In a preferred embodiment of the present invention, the homopolymer polypropylene a has at least one of the following characteristics: the melting point of the homopolymer polypropylene a is 160-170°C; and / or,

[0018] The homopolymer polypropylene a has a melt flow rate of 0.5-50 g / 10 min at 230 °C and 2.16 kg load, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min; and / or,

[0019] The isotacticity (mm) of the homopolymer polypropylene a is not less than 96%.

[0020] In a preferred embodiment of the present invention, the impact-resistant copolymer polypropylene b has at least one of the following characteristics: the melting point of the impact-resistant copolymer polypropylene b is 150-170°C; and / or,

[0021] The monomer for the copolymerization of the impact-resistant polypropylene b and propylene is ethylene or butene, with an ethylene or butene content of 2-50% wt, preferably 3-20% wt, more preferably 5-15% wt, and / or...

[0022] The impact-resistant copolymer polypropylene b has a melt flow rate of 0.5-50 g / 10 min at 230°C and 2.16 kg load, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min; and / or,

[0023] The impact strength of the impact-resistant copolymer polypropylene b is not less than 20 KJ / m. 2 (Tested at 23℃).

[0024] According to the inventors' research, when the melt flow rate and polymer composition ratio of polypropylene composition A are within the above-mentioned preferred range, the impact-resistant copolymer polypropylene b in the composition can effectively absorb impact energy, meeting the impact performance requirements and giving the sheet good impact performance. Simultaneously, because the macromolecular chain segments in homopolymer polypropylene a are relatively regular, crystallization occurs during the sheet preparation process, thus the sheet also has good tensile properties.

[0025] In a preferred embodiment of the present invention, the random copolymer polypropylene x has at least one of the following characteristics: the melting point of the random copolymer polypropylene x is 120-140℃; and / or,

[0026] The random copolymer polypropylene x has a melt flow rate of 0.5-50 g / 10 min at 230 °C and 2.16 kg load, preferably 1-20 g / 10 min, and more preferably 3-18 g / 10 min; and / or,

[0027] The random copolymer polypropylene x is a copolymer of propylene and ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer or a propylene-ethylene binary copolymer.

[0028] In a preferred embodiment of the present invention, the melt flow rate of the thermal bonding enhancer y at 190°C and 2.16 kg load is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and more preferably 1-18 g / 10 min.

[0029] The heat-bonding reinforcing agent y is selected from one or more of polyolefin elastomers, ethylene propylene diene monomer (EPDM) rubber, SEBS, SBS, EVA, and petroleum resins; preferably,

[0030] The polyolefin elastomer is a copolymer elastomer of ethylene and propylene and / or α-olefins; more preferably, the α-olefin is a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or,

[0031] The petroleum resin is a C5 and / or C9 hydrogenated petroleum resin, preferably with a softening point of 100-150°C; more preferably, the petroleum resin is a cyclopentadiene type resin.

[0032] According to the inventors' research, when the melt flow rate and polymer composition ratio of polypropylene compositions B and B' are within the preferred range, the low-melting-point random copolymer polypropylene x and the heat-bonding reinforcing agent y in the composition can significantly reduce the hot-pressing temperature and widen the hot-pressing temperature window. Furthermore, the heat-bonding reinforcing agent y provides good adhesion performance for the sheet and can further improve the interlayer peel strength.

[0033] In a preferred embodiment of the present invention, layer A further contains a β-crystal nucleating agent; preferably,

[0034] The β-crystal nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, group IIA binary complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylate nucleating agents; and / or,

[0035] Based on a total of 100 parts by weight of the polypropylene composition A, the content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight. Specifically, for example, the content of the β-crystal nucleating agent can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 parts by weight.

[0036] The inventors of this invention have surprisingly discovered that the polypropylene sheet obtained can be hot-pressed to obtain a polypropylene / metal composite material, which has superior mechanical properties and better interlaminar peel strength. Even at lower hot-pressing temperatures and over a wider range of hot-pressing temperatures, the polypropylene / metal composite material obtained has higher interlaminar peel strength.

[0037] The BAB' layer structure of the polypropylene sheet can be prepared by various methods. In a preferred embodiment of the present invention, the BAB' layer structure of the polypropylene sheet is obtained by co-extrusion of components including polypropylene composition A, polypropylene composition B, and B'. Preferably, the process includes co-extruding polypropylene composition A, polypropylene composition B, and B' according to the BAB' structure, casting or calendering, stretching, and slitting to obtain the polypropylene sheet.

[0038] The polypropylene composition A is melt-blended using the conditions and equipment of existing polyolefin melt-blending technology. Preferably, the melting temperature is 150-170°C, and the equipment is preferably a twin-screw extruder.

[0039] In a preferred embodiment of the present invention, the preparation of the polypropylene composition B includes melt blending of components including the random copolymer polypropylene x and the thermal bonding reinforcing agent y. The melt blending conditions and equipment for the polypropylene composition B adopt the conditions and equipment for melt blending of polyolefins in the prior art. Preferably, the melt temperature is 110-150°C, and the equipment is preferably a twin-screw extruder.

[0040] The temperature range for co-extrusion molding and casting is relatively wide. In a preferred embodiment of the present invention, in step (1), the temperature for co-extrusion molding and casting is independently selected from 200-240°C; the temperature of the calendering roll is 50-70°C.

[0041] The range of stretching conditions is relatively wide. In a preferred embodiment of the present invention, the stretching conditions include: the stretching method is free stretching, and / or solid-state stretching, and / or multi-stage stretching; the stretching temperature is 90-165℃, preferably 90-140℃, and more preferably 90-119℃; the stretching ratio is 1-20 times, preferably 2-15 times.

[0042] In a preferred embodiment of the present invention, the longitudinal tensile strength of the stretched polypropylene sheet is greater than or equal to 30 MPa, more preferably 30 MPa-1 GPa; and most preferably 300-800 MPa.

[0043] The polypropylene fabric is a three-dimensional polypropylene fabric obtained by weaving the polypropylene sheets described above; preferably, the polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0044] To facilitate weaving, it is preferable to cut the polypropylene sheet into polypropylene sheet cuts with a width of 2-5mm, and then weave them into polypropylene fabric.

[0045] In a preferred embodiment of the present invention, the polypropylene / metal composite material is prepared by sequentially stacking multiple layers of polypropylene sheets and / or polypropylene fabrics with the metal material layer, hot-pressing and fusing them, and then cooling and shaping them.

[0046] In a preferred embodiment of the present invention, the total number of layers of the polypropylene sheet and / or polypropylene fabric is greater than or equal to 2 layers, more preferably 2-200 layers; and most preferably 4-100 layers.

[0047] In a preferred embodiment of the present invention, the areal density of the polypropylene / metal composite material is greater than or equal to 600 g / m³. 2 More preferably 600-35000 g / m 2 The optimal value is 800-12000 g / m³. 2 .

[0048] In a preferred embodiment of the present invention, the longitudinal tensile strength of the polypropylene / metal composite material is greater than or equal to 280 MPa, preferably greater than or equal to 300 MPa.

[0049] In a preferred embodiment of the present invention, the polypropylene / metal composite material has at least one of the following characteristics:

[0050] Longitudinal tensile strength ≥280 MPa, preferably ≥300 MPa;

[0051] Interlayer peel strength ≥1N / mm, preferably ≥1.1N / mm;

[0052] Tensile strength was determined according to the method specified in GB / T1040.1-2018, and interlaminar peel strength was determined according to the method specified in GB / T2358-98. The corresponding specimens for the above two tests were the standard specimens required in the above testing standards.

[0053] When the polypropylene / metal composite material is obtained by hot pressing 24 layers of polypropylene fabric and 1 layer of metal mesh, and the thickness is about 1.79 mm, the drop hammer impact strength is ≥280 J, preferably ≥300 J.

[0054] The drop hammer impact strength was determined according to the method specified in GB / T14153-1993, and the thickness of the sample was the same as the thickness of the prepared product.

[0055] According to the present invention, the invention can be achieved simply by providing a plurality of through holes on the metal material layer, thereby bringing the polypropylene coating layers on both sides of the metal material layer into contact. The distribution and morphology of the holes on the metal material layer are not particularly required. To further improve the mechanical properties of the polypropylene / metal composite material and to achieve better interlaminar peel strength, the metal material layer is preferably a metal mesh. The metal mesh includes, but is not limited to, stainless steel mesh, carbon steel mesh, galvanized steel mesh, and alloy mesh.

[0056] Preferably, the metal mesh is selected from at least one of stainless steel mesh, carbon steel mesh, galvanized steel mesh, and alloy mesh.

[0057] Preferably, the diameter of the metal wires in the metal mesh is 0.02-2 mm, more preferably 0.03-1 mm; and / or, the number of meshes is 10-1000, more preferably 50-500. In this preferred embodiment, the resulting polypropylene / metal composite material has further improved interlaminar peel strength.

[0058] Preferably, the number of metal material layers is greater than or equal to 1 layer, more preferably 1-50 layers, and most preferably 1-20 layers.

[0059] In a more preferred embodiment of the present invention, the polypropylene / metal composite material is prepared by hot pressing multiple layers of polypropylene sheets and / or polypropylene fabrics as described above, and a metal mesh as described above. Preferably, the multiple layers of polypropylene sheets and / or polypropylene fabrics are stacked at 0-90° angles along their respective machine directions from top to bottom; preferably, the number of layers is greater than or equal to 2 layers, more preferably 2-200 layers, and most preferably 4-100 layers. The metal mesh is placed between the polypropylene sheets and / or polypropylene fabrics; the number of metal mesh layers is greater than or equal to 1 layer, more preferably 1-50 layers, and most preferably 1-20 layers. The areal density of the polypropylene / metal composite material is greater than or equal to 600 g / m³. 2More preferably 600-35000 g / m 2 The optimal value is 800-12000 g / m³. 2 In a preferred embodiment of the present invention, the polypropylene fabrics in each of the stacked layers may contain the same or different polypropylene compositions A, and each layer may contain polypropylene fabric A independently selected, preferably the same polypropylene composition A in each layer.

[0060] In a more preferred embodiment of the present invention, the polypropylene / metal composite material comprises a polypropylene composite matrix formed by stacking all polypropylene coating layers and at least one metal material layer disposed in the polypropylene composite matrix; the polypropylene composite matrix comprises a plurality of sequentially stacked polypropylene sheet unit groups; each polypropylene sheet unit group comprises at least one identical or different polypropylene sheet unit, and each polypropylene sheet unit comprises a core layer A. i and located in core layer A i Outer B on both sides i B' i The structure is B i A i B' i The structure of the polypropylene composite material, from bottom to top, is group n...group i...group 2, group 1, group 2...group i...group n, and the total number of polypropylene sheet unit groups is 2n-1; i and n are both integers not less than 2, and i≤n;

[0061] Among them, the core layer A in the polypropylene sheet unit i Composition A containing polypropylene i Outer layer B i With outer layer B' i Whether the composition is the same or different, each composition corresponds to a polypropylene composition B. i Polypropylene composition B' i ,

[0062] The polypropylene composition A i The melting point is greater than that of the polypropylene composition B. i The polypropylene composition B' i The melting point of the outermost layer in the i-th group is greater than or equal to the average melting point of the outermost layer in the (i-1)-th group.

[0063] In a more preferred embodiment of the present invention, polypropylene composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' iThe difference in melting point is greater than or equal to 5°C, preferably greater than or equal to 10°C, more preferably greater than or equal to 20°C, and even more preferably 20-60°C.

[0064] Through research, the inventors unexpectedly discovered that when the average melting point of all outer layers in group i is greater than the average melting point of all outer layers in group i-1, it has a better technical effect than when the two are equal. That is, the polypropylene / metal composite material has further superior mechanical properties and further better interlayer peel strength.

[0065] More preferably, the difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group i-1 is the same or different, and is 1-40°C, preferably 1-10°C, and more preferably 1-5°C.

[0066] According to the present invention, the total number of stacked polypropylene sheet unit groups is 2n-1. The present invention has a wide range of options for the total number of stacked polypropylene sheet unit groups. Preferably, 2≤n≤100, more preferably, 2≤n≤50, and even more preferably, 2≤n≤30.

[0067] According to the present invention, the number of polypropylene sheet units included in each polypropylene sheet unit group can be selected within a wide range. In a preferred embodiment of the present invention, each polypropylene sheet unit group independently includes 1 to 10, preferably 1 to 5, more preferably 1 to 3 identical or different polypropylene sheet units, and even more preferably 1 polypropylene sheet unit. Preferably, the number of polypropylene sheet units included in each polypropylene sheet unit group is the same.

[0068] Preferably, but not necessarily, the melting point of any outer layer in each group is within ±10°C, within ±5°C, more preferably within ±3°C, and more preferably within ±1°C of the average melting point of all outer layers in the group.

[0069] In embodiments where each polypropylene sheet unit group comprises only one polypropylene sheet unit, for example, the structure of the polypropylene composite material can be arranged from bottom to top as B n A n B' n ...B i A i B' i ...B2A2B'2, B1A1B'1, B2A2B'2...B i A i B' i ...B n A n B' n The total number of layers in the polypropylene sheet unit is 2n-1; i and n are both integers not less than 2, and i≤n.

[0070] In embodiments where each polypropylene sheet unit group comprises two or more polypropylene sheet units, for example, the structure of the i-th polypropylene sheet unit group is B. i1 A i1 B' i1 B i2 A i2 B' i2 ...B ip A ip B' ip The structure of the polypropylene composite material can be arranged from bottom to top as follows: (B) n1 A n1 B' n1 B n2 A n2 B' n2 ...B nq A nq B' nq )……(B i1 A i1 B' i1 B i2 A i2 B' i2 ...B ip A ip B' ip )……(B 21 A 21 B' 21 B 22 A 22 B' 22 ...B 2k A 2k B' 2k (B) 11 A 11 B' 11 B 12 A 12 B' 12 ...B 1j A 1j B' 1j (B) 21 A 21 B' 21 B 22 A 22 B' 22 ...B 2k A 2k B' 2k )……(B i1 A i1 B' i1 B i2 A i2 B' i2 ...Bip A ip B' ip )……(B n1 A n1 B' n1 B n2 A n2 B' n2 ...B nq A nq B' nq The total number of polypropylene sheet units stacked is j+2k+……2p+……2q; j, k, p, and q are each independent integers not less than 2, preferably 2 to 10, more preferably 2 to 5, and even more preferably 2 to 3.

[0071] The arrangement of the metal material layers in the polypropylene composite matrix has a wide range of options. Preferably, the number of polypropylene sheet units on both sides of each metal material layer is approximately the same. For example, when there is only one metal material layer, it is preferable that the metal material layer is located relatively close to the middle of the polypropylene composite matrix. Preferably, the difference in the number of polypropylene sheet units on both sides of each metal material layer is less than or equal to 5, and more preferably less than or equal to 2.

[0072] The second aspect of the present invention is to provide a method for preparing the polypropylene / metal composite material described in the first aspect, comprising stacking multiple layers of polypropylene sheets and / or polypropylene fabrics with the metal material layer in sequence, hot-pressing and fusing them, and then cooling and shaping them to obtain the polypropylene / metal composite material.

[0073] Preferably, the multilayer polypropylene sheets are stacked from top to bottom at an angle of 0-90° along their respective machine directions.

[0074] Preferably, the multilayer polypropylene fabric is stacked from top to bottom with the warp direction placed at an angle of 0-90° between the warp directions.

[0075] Preferably, the total number of layers of the multilayer polypropylene sheet and / or multilayer polypropylene fabric is greater than or equal to 2 layers, more preferably 2-200 layers; and most preferably 4-100 layers.

[0076] Preferably, the number of metal material layers is greater than or equal to 1 layer, more preferably 1-50 layers; and most preferably 1-20 layers.

[0077] In a preferred embodiment of the present invention, the temperature of the hot pressing fusion is 115-170°C, preferably 115-159°C, and more preferably 140-159°C.

[0078] Preferably, the pressure of the hot-press fusion is 2-10 MPa.

[0079] Preferably, the preheating time for hot pressing fusion is 5-600s, and the hot pressing time is 1-600s, preferably 10-500s.

[0080] Preferably, the cooling and shaping pressure is 2-8 MPa, and the cooling and shaping time is 30-700 s.

[0081] In a preferred embodiment of the present invention, adjacent layers of the polypropylene sheet stack are placed at 0-90° along their respective machine directions, i.e., the stretching direction (MD).

[0082] In a preferred embodiment of the present invention, adjacent layers of the polypropylene fabric stack are placed at an angle of 0-90° between the warp and weft directions.

[0083] The metal mesh is placed between the polypropylene sheet and / or polypropylene fabric.

[0084] In a more preferred embodiment of the present invention, the method for preparing the high-strength, high-impact polypropylene / metal composite material includes the following steps:

[0085] Step a: Polypropylene composition A, polypropylene composition B, and B' are co-extruded according to the BAB' structure and then cast or calendered to obtain a polypropylene co-extruded sheet; preferably, the extrusion casting or calendering temperature is 200-240°C, and the temperature of the calendering roll is 50-70°C.

[0086] Step b: The polypropylene co-extruded sheet is stretched at a certain temperature to obtain a polypropylene stretched sheet; preferably, the stretching temperature is 90-165℃, more preferably 90-140℃, and even more preferably 90-119℃, with a stretching ratio of 1-15 times, preferably 2-9 times.

[0087] Step c: Cut the polypropylene stretched sheet into polypropylene flat strips, and weave the flat strips into polypropylene fabrics; preferably, the width of the polypropylene flat strips is 2-5 mm, and the polypropylene fabrics include plain weave, twill weave, satin weave or other three-dimensional polypropylene fabrics.

[0088] Step d: The polypropylene sheet and / or the polypropylene fabric are laminated and hot-pressed with a metal mesh, and then cooled and shaped to form a polypropylene / metal composite material; preferably, in step d, the hot-pressing conditions are: hot-pressing temperature 115-170℃, preferably 115-159℃, more preferably 140-159℃; hot-pressing pressure 2-10 MPa, preheating time 5-600s, hot-pressing time 1-600s, preferably 10-500s, cooling pressure 2-8 MPa, cooling time 30s-700s; preferably, adjacent polypropylene fabrics in the polypropylene composite material can be placed at 0-90° between the warp directions, and the metal mesh is placed between the polypropylene sheet and / or the polypropylene fabric.

[0089] According to some embodiments of the present invention, in step c, a high-speed slitting machine with multiple blades can be used to cut the oriented polypropylene flat strip with a width of 2-5 mm; the oriented flat strip is then woven into plain weave, twill weave, satin weave or other three-dimensional polypropylene fabrics using a commercial weaving machine according to the designed fabric structure.

[0090] According to a preferred embodiment of the present invention, the pressure is preferably maintained continuously during the hot pressing and cooling process without any decrease. The hot pressing process is continuous, and preferably a continuous hot pressing composite material molding equipment is adopted, consisting of a preheating machine, a crawler-type continuous planar hot press, a crawler-type continuous planar cooling press, a sheet cutting machine, and a sheet stacking machine arranged in sequence. Preferably, the crawler-type continuous planar hot press has a preheating unit, an independent heating and pressurizing unit, an air cooling unit, and a lifting mechanism.

[0091] In the preparation process, the polypropylene sheets and / or the polypropylene fabric, along with the metal mesh, are sequentially layered and preheated in a preheating machine. The preheated samples are then sequentially hot-pressed and fused using a tracked flatbed hot press, followed by cooling and shaping using a tracked continuous flatbed cooling press, resulting in a polypropylene / metal composite material, i.e., a laminated hot-pressed product. Subsequently, the product is sliced ​​as needed using a sheet cutter, and then stacked and arranged using a sheet stacking machine. The hot-pressing temperature is controlled by the preheating unit, independent heating and pressurizing unit, and air-cooling unit in the tracked flatbed hot press, while the hot-pressing pressure is controlled by a lifting mechanism. According to the inventors' research, when the preparation process parameters are within the preferred range, and the aforementioned equipment is used to prepare the polypropylene / metal composite material, the polypropylene / metal composite material exhibits better tensile strength, impact performance, and interlaminar peel strength.

[0092] A third aspect of the present invention is to provide the application of the polypropylene / metal composite material described in the first aspect and the polypropylene / metal composite material prepared by the preparation method described in the second aspect in the fields of sports protection, automobile manufacturing, military materials and consumer products.

[0093] According to specific embodiments of the present invention, the materials field includes the luggage and transportation industry, the footwear industry, the automobile manufacturing industry, the sports equipment manufacturing industry, the audio equipment manufacturing industry, and the military field.

[0094] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0095] (1) The polypropylene / metal composite material of the present invention has good tensile strength, impact performance and interlaminar peel strength.

[0096] The polypropylene / metal composite material has the following characteristics:

[0097] The longitudinal tensile strength is ≥280 MPa, preferably ≥300 MPa; the interlayer peel strength is ≥1 N / mm, preferably ≥1.1 N / mm; when the polypropylene / metal composite material is obtained by hot pressing 24 layers of polypropylene fabric and 1 layer of metal mesh, and the thickness is about 1.79 mm, the drop hammer impact strength is ≥280 J, preferably ≥300 J.

[0098] (2) The polypropylene / metal composite material of the present invention is suitable for preparation at a lower hot pressing temperature and a wider hot pressing temperature range, which effectively reduces the energy consumption of equipment and the damage to the composite material under high temperature operation. At the same time, it still has good interlayer peel strength when prepared at a lower hot pressing temperature.

[0099] (3) This preparation method can reduce the hot pressing operation time, while improving production efficiency and reducing production energy consumption.

[0100] (4) The present invention reduces the hot pressing temperature and expands the hot pressing temperature range to 50°C; effectively reducing equipment energy consumption and damage to composite materials under high temperature operation. Detailed Implementation

[0101] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0102] In the following embodiments and comparative examples:

[0103] The extrusion calender and stretching equipment were purchased from Tianjin Hengrui Company, model HRPC-800 three-layer co-extrusion plastic stretching sheet production line.

[0104] The properties of the polypropylene / metal composite material, polypropylene composition, and sheet were tested according to the following methods, and the test results of the polypropylene / metal composite material are shown in Table 1:

[0105] (1) Melt mass flow rate (MFR): The test shall be conducted in accordance with the method specified in GB / T 3682.2—2018, wherein the test temperature for homopolymer polypropylene and impact copolymer polypropylene is 230℃ and the load is 2.16kg; the test temperature for thermal adhesive reinforcing agent is 190℃ and the load is 2.16kg.

[0106] (2) Melting point, determined according to the method specified in GB / T 28724-2012;

[0107] (3) Tensile strength: determined according to the method specified in GB / T1040.1-2018;

[0108] (4) Drop hammer impact strength: determined according to the method specified in GB / T14153-1993;

[0109] (5) Interlayer peel strength: The test shall be conducted in accordance with the method specified in QB / T2358-98.

[0110] (6) Density, determined according to the method specified in GB / T 1033.1-2008;

[0111] (7) Surface density: determined according to the method specified in ASTM D1622-2020.

[0112] In the following examples, the β-crystal nucleating agent with the brand name VP101B was sourced from the Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation; the sources of some raw materials are described in the examples, and the remaining raw materials are commercially available unless otherwise specified.

[0113] Example 1

[0114] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0115] (1) Preparation of polypropylene composition A:

[0116] Component a is a homopolymer polypropylene self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 160℃, a melt flow rate of 3.2 g / 10 min, and an isotacticity of 97%; component b is a polypropylene impact copolymer self-produced by the Beijing Research Institute of Chemical Industry of Sinopec (impact strength 23 KJ / m under 23℃ testing conditions). 2 The ethylene content is 11% wt, the melt flow rate is 2.0 g / 10 min, and the melting point is 155℃.

[0117] The components obtained above were weighed and mixed according to the specified proportions, wherein component a (Wa) had a mass fraction of 80 parts by weight and component b (Wb) had a mass fraction of 20 parts by weight. 0.05 parts by weight of β-crystal nucleating agent (VP101B) were added. The mixture was then added to a high-speed mixer and mixed thoroughly. The mixed material was then fed into the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws through the feeder. During processing, the screw temperature was maintained between 200-230°C. After being melted and mixed evenly by the screws, extruded, granulated, and dried, polypropylene composition granules were obtained. The melt flow rate (MFRA) was measured to be 4.6 / 10 min; the melting point of polypropylene composition A was 157°C.

[0118] (2) Preparation of polypropylene composition B:

[0119] Component x is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 140℃ and a melt flow rate of 6.6 g / 10 min. Component y is a polyolefin elastomer of grade 6102 purchased from Exxon. It is an ethylene-propylene copolymer with an ethylene content of 16% wt and a melt flow rate of 1.4 g / 10 min at 190℃ and a load of 2.16 kg.

[0120] The components prepared above were weighed and mixed according to the ratio, wherein the mass part of component x, Wx, was 85 parts by weight, the mass part of component y, Wy, was 15 parts by weight, and the other steps were the same as in step (1). Finally, polypropylene composition B granules were obtained. The melt flow rate MFRB was tested to be 5.2 g / 10 min, and the melting point was 138 °C.

[0121] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0122] The polypropylene composition A and polypropylene composition B granules obtained in steps (1) and (2) above are dried. Then, polypropylene composition A is added to the core extruder of a multilayer extrusion calender, and polypropylene composition B is added to the upper and lower surface extruders of a multilayer extrusion casting machine.

[0123] After the granules are co-extruded and compounded through the die of an extruder, they pass through calendering rollers and traction rollers in sequence, and then undergo solid-phase stretching, edge trimming and winding to obtain the sheet material.

[0124] The extrusion casting temperature is 230℃, and the calendering roll temperature is 55℃. The solid-phase stretching process is carried out at a temperature of 135℃, a stretching rate of 2 m / min, and a stretching ratio of 7 times. After stretching, the film is wound up to form a polypropylene sheet (composite film), which consists of an upper surface layer (film layer B), a core layer (film layer A), and a lower surface layer (film layer B).

[0125] The thickness of the polypropylene sheet (composite film) mentioned above is 80 μm, wherein the thickness of film layer A accounts for 80% of the total thickness of the sheet.

[0126] (4) Preparation of polypropylene fabric:

[0127] The three-layer co-extruded polypropylene sheet obtained in step (3) above is cut into a high-speed slitting machine with multiple blades to obtain an oriented polypropylene flat strip with a width of 3mm; the oriented flat strip is woven into a plain weave polypropylene fabric according to the designed fabric structure using a commercial weaving machine.

[0128] (5) Preparation of polypropylene / metal composite materials:

[0129] The polypropylene fabric and metal mesh obtained in step (4) were laminated and hot-pressed together, and then cooled and shaped to form a polypropylene / metal composite material. The polypropylene / metal composite material includes 24 layers of polypropylene fabric and 1 layer of stainless steel mesh with a diameter of 0.08 mm and a mesh size of 100 meshes. The stainless steel mesh is placed in the middle of the polypropylene fabric, and 12 layers of polypropylene fabric are placed on each side of the stainless steel mesh. The polypropylene fabric is placed at a 90° angle between the warp and weft directions. The hot-pressing conditions used are: temperature 150℃, hot-pressing pressure 5 MPa, preheating time 180 s, hot-pressing time 180 s, and cooling time 600 s. The thickness of the prepared polypropylene / metal composite material is 1.79 mm, and the areal density is shown in Table 1.

[0130] Example 2

[0131] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0132] (1) Preparation of polypropylene composition A:

[0133] Component a is a homopolymer polypropylene self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 165℃, a melt flow rate of 8.1 g / 10 min, and an isotacticity of 97%; component b is a polypropylene impact copolymer self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with an impact strength of 25 KJ / m under a test condition of 23℃. 2 The ethylene content is 8% wt, the melt flow rate is 3.2 g / 10 min, and the melting point is 155℃.

[0134] The components obtained above were weighed and mixed according to the specified proportions, with component a (Wa) comprising 70 parts by weight and component b (Wb) comprising 30 parts by weight. 0.05 parts by weight of β-crystal nucleating agent (VP101B) were added. The mixture was then added to a high-speed mixer and mixed thoroughly. The mixed material was then fed into the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws via the feeder. During processing, the screw temperature was maintained between 200-230°C. After melting and mixing evenly in the screws, extrusion, granulation, and drying, polypropylene composition granules were obtained. The melt flow rate (MFRA) was measured to be 7.3 / 10 min, and the melting point of polypropylene composition A was 161°C.

[0135] (2) Preparation of polypropylene composition B:

[0136] Component x is a random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, with a melting point of 134℃. It is an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min. Component y is a polyolefin elastomer produced by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene copolymer with an ethylene content of 15% wt. It has a melting point of 105℃ and a melt flow rate of 9 g / 10 min at 190℃ and a load of 2.16 kg.

[0137] The components obtained above were weighed and mixed according to the specified proportions, wherein the mass fraction of component x, Wx, was 80 parts by weight and the mass fraction of component y, Wy, was 20 parts by weight. Other steps were the same as in step (1), and polypropylene composition B granules were finally obtained. The melt flow rate MFRB was tested to be 9.6 g / 10 min. The melting point of polypropylene composition B is 130℃.

[0138] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0139] The preparation process is the same as step (3) in Example 1.

[0140] (4) Preparation of polypropylene fabric:

[0141] The preparation process is the same as step (4) of Example 1.

[0142] (5) Preparation of polypropylene / metal composite materials:

[0143] The preparation process is the same as step (5) in Example 1.

[0144] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0145] Example 3

[0146] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0147] (1) Preparation of polypropylene composition A:

[0148] Same as in Example 1, wherein component a (Wa) has 90 parts by weight and component b (Wb) has 10 parts by weight. 0.05 parts by weight of β-crystal nucleating agent (VP101B) were added. Polypropylene composition A granules were obtained, and its melt flow rate (MFRA) was measured to be 6.8 / 10 min. The melting point of polypropylene composition A was 158°C.

[0149] (2) Preparation of polypropylene composition B:

[0150] Same as in Example 1, wherein the mass fraction of component x, Wx, is 90 parts by weight and the mass fraction of component y, Wy, is 10 parts by weight, and finally polypropylene composition B granules are obtained. The melt flow rate MFRB is tested to be 8.7 g / 10 min and the melting point of polypropylene composition B is 139 °C.

[0151] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0152] The preparation process is the same as step (3) in Example 1.

[0153] (4) Preparation of polypropylene fabric:

[0154] The preparation process is the same as step (4) of Example 1.

[0155] (5) Preparation of polypropylene / metal composite materials:

[0156] The preparation process is the same as step (5) in Example 1.

[0157] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0158] Example 4

[0159] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0160] (1) Preparation of polypropylene composition A:

[0161] The preparation process is the same as step (1) in Example 1.

[0162] (2) Preparation of polypropylene composition B:

[0163] The preparation process is the same as step (2) of Example 1.

[0164] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0165] The main steps are the same as in Example 1. The thickness of the polypropylene sheet is 80 μm, wherein the thickness of the film layer A accounts for 90% of the total thickness of the sheet.

[0166] (4) Preparation of polypropylene fabric:

[0167] The preparation process is the same as step (4) of Example 1.

[0168] (5) Preparation of polypropylene / metal composite materials:

[0169] The preparation process is the same as step (5) in Example 1.

[0170] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0171] Example 5

[0172] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0173] (1) Preparation of polypropylene composition A:

[0174] The preparation process is the same as step (1) in Example 1.

[0175] (2) Preparation of polypropylene composition B:

[0176] The preparation process is the same as step (2) of Example 1.

[0177] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0178] The main steps are the same as in Example 1. The thickness of the polypropylene sheet is 80 μm, wherein the thickness of the film layer A accounts for 70% of the total thickness of the sheet.

[0179] (4) Preparation of polypropylene fabric:

[0180] The preparation process is the same as step (4) of Example 1.

[0181] (5) Preparation of polypropylene / metal composite materials:

[0182] The preparation process is the same as step (5) in Example 1.

[0183] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0184] Example 6

[0185] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0186] (1) Preparation of polypropylene composition A:

[0187] The preparation process is the same as step (1) in Example 1.

[0188] (2) Preparation of polypropylene composition B:

[0189] The preparation process is the same as step (2) of Example 1.

[0190] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0191] The preparation process is the same as step (3) in Example 1.

[0192] (4) Preparation of polypropylene fabric:

[0193] The main steps are the same as step (4) in Example 1. The oriented flat strip is woven into a satin polypropylene fabric by using a commercial weaving machine according to the designed fabric structure.

[0194] (5) Preparation of polypropylene / metal composite materials:

[0195] The preparation process is the same as step (5) in Example 1.

[0196] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0197] Example 7

[0198] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0199] (1) Preparation of polypropylene composition A:

[0200] The preparation process is the same as step (1) in Example 1.

[0201] (2) Preparation of polypropylene composition B:

[0202] The preparation process is the same as step (2) of Example 1.

[0203] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0204] The main preparation process is the same as step (3) in Example 1. The sheet stretching ratio is 10 times. The thickness of the polypropylene sheet (composite film) described above is 70 μm.

[0205] (4) Preparation of polypropylene fabric:

[0206] The preparation process is the same as step (4) of Example 1.

[0207] (5) Preparation of polypropylene / metal composite materials:

[0208] The preparation process is the same as step (5) in Example 1.

[0209] The prepared polypropylene / metal composite material has a thickness of 1.71 mm and its areal density is shown in Table 1.

[0210] Example 8

[0211] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0212] (1) Preparation of polypropylene composition A:

[0213] The preparation process is the same as step (1) in Example 1.

[0214] (2) Preparation of polypropylene composition B:

[0215] The preparation process is the same as step (2) of Example 1.

[0216] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0217] The preparation process is the same as step (3) in Example 1.

[0218] (4) Preparation of polypropylene fabric:

[0219] The preparation process is the same as step (4) of Example 1.

[0220] (5) Preparation of polypropylene / metal composite materials:

[0221] The main preparation process is the same as step (5) in Example 1. The polypropylene fabric is placed at a 45° angle between the warp and weft directions.

[0222] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0223] Example 9

[0224] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0225] (1) Preparation of polypropylene composition A:

[0226] The preparation process is the same as step (1) in Example 1.

[0227] (2) Preparation of polypropylene composition B:

[0228] The preparation process is the same as step (2) of Example 1.

[0229] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0230] The preparation process is the same as step (3) in Example 1.

[0231] (4) Preparation of polypropylene fabric:

[0232] The preparation process is the same as step (4) of Example 1.

[0233] (5) Preparation of polypropylene / metal composite materials:

[0234] The main preparation process is the same as step (5) in Example 1. The polypropylene fabric is placed with the warp direction at 0° to the warp direction.

[0235] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0236] Example 10

[0237] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, and three-layer co-extruded polypropylene sheet provided by the present invention.

[0238] (1) Preparation of polypropylene composition A:

[0239] The preparation process is the same as step (1) in Example 1.

[0240] (2) Preparation of polypropylene composition B:

[0241] The preparation process is the same as step (2) of Example 1.

[0242] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0243] The preparation process is the same as step (3) in Example 1.

[0244] (4) Preparation of polypropylene / metal composite materials:

[0245] Instead of preparing polypropylene fabric, the three-layer co-extruded polypropylene sheet obtained in step (3) was used to replace the polypropylene fabric obtained in step (4) of Example 1, and the sheets were sequentially stacked and hot-pressed according to step (5) of Example 1. The thickness of the prepared polypropylene / metal composite material was 1.76 mm, and the areal density is shown in Table 1.

[0246] Example 11

[0247] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0248] (1) Preparation of polypropylene composition A:

[0249] The preparation process is the same as step (1) in Example 1.

[0250] (2) Preparation of polypropylene composition B:

[0251] The preparation process is the same as step (2) of Example 1.

[0252] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0253] The preparation process is the same as step (3) in Example 1.

[0254] (4) Preparation of polypropylene fabric:

[0255] The preparation process is the same as step (4) of Example 1.

[0256] (5) Preparation of polypropylene / metal composite materials:

[0257] The main steps are the same as in Example 1. The temperature is 155℃, the hot-pressing pressure is 10 MPa, the preheating time is 300 s, the hot-pressing time is 300 s, and the cooling time is 700 s. The thickness of the prepared polypropylene / metal composite material is 1.72 mm, and the areal density is shown in Table 1.

[0258] Example 12

[0259] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0260] (1) Preparation of polypropylene composition A:

[0261] The preparation process is the same as step (1) in Example 1.

[0262] (2) Preparation of polypropylene composition B:

[0263] The preparation process is the same as step (2) of Example 1.

[0264] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0265] The preparation process is the same as step (3) in Example 1.

[0266] (4) Preparation of polypropylene fabric:

[0267] The preparation process is the same as step (4) of Example 1.

[0268] (5) Preparation of polypropylene / metal composite materials:

[0269] The polypropylene fabric and metal mesh obtained in step (4) were laminated and hot-pressed together, and then cooled and shaped to form a polypropylene / metal composite material. The polypropylene / metal composite material includes 48 layers of polypropylene fabric and 4 layers of stainless steel mesh with a diameter of 0.1 mm and a mesh size of 500 mesh. The stainless steel mesh is placed in the middle of the polypropylene fabric, and 8 layers of polypropylene fabric are placed between the stainless steel meshes. The polypropylene fabric is placed at a 90° angle between the warp and weft directions. The hot-pressing conditions used are: temperature 155℃, hot-pressing pressure 10 MPa, preheating time 300 s, hot-pressing time 300 s, and cooling time 700 s. The thickness of the prepared polypropylene / metal composite material is 4.12 mm, and the areal density is shown in Table 1.

[0270] Example 13

[0271] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0272] (1) Preparation of polypropylene composition A:

[0273] The preparation process is the same as step (1) in Example 1.

[0274] (2) Preparation of polypropylene composition B:

[0275] The preparation process is the same as step (2) of Example 1. The difference is that component B... i and x i The materials selected are as follows:

[0276] Component x1 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 110℃; Component x2 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 115℃; Component x3 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 120℃; Component x4 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 125℃; Component x5 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. Component x1 is an ethylene-propylene-butene terpolymer with a melting point of 130℃; Component x2 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 135℃; Component x3 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 138℃; Component x4 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 140℃; Component x5 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 143℃; Component x6 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 135℃; Component x7 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 138℃; Component x8 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 140℃; Component x9 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 143℃; Component x 10 This is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 145℃; component x 11 This is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 148℃; component x 12 This is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 150℃; wherein, components x1-x 12 The molecular weight distribution Mw / Mn is between 7 and 10, and the components x1-x 12 The melt flow rates are all between 1 and 20 g / 10 min.

[0277] Finally, polypropylene composition B was obtained. i Granular material (i.e., x) i +y=B i (i = 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12), the melting point of B1 is 110℃, B2 is 113℃, B3 is 117℃, B4 is 123℃, B5 is 127℃, B6 is 133℃, B7 is 135℃, B8 is 137℃, and B9 is 140℃. 10 The melting point of B is 142℃. 11 The melting point of B is 146℃. 12 Its melting point is 148℃.

[0278] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0279] The preparation process is the same as step (3) in Example 1.

[0280] (4) Preparation of polypropylene fabric:

[0281] The preparation process is the same as step (4) of Example 1.

[0282] (5) Preparation of polypropylene / metal composite materials:

[0283] The polypropylene fabric and metal mesh obtained in step (4) are laminated and hot-pressed together, and then cooled and shaped to form a polypropylene / metal composite material. The polypropylene / metal composite material includes 23 layers of polypropylene fabric and 1 layer of stainless steel mesh with a diameter of 0.08 mm and a mesh size of 100. The stainless steel mesh is placed in the middle of the polypropylene fabric, and 12 layers and 11 layers of polypropylene fabric are respectively placed on both sides of the stainless steel mesh. The polypropylene fabric and stainless steel mesh are stacked sequentially, from bottom to top as B 12 A 12 B 12… B9A9B 9… B3A3B3, B2A2B2, B1A1B1, stainless steel mesh, B2A2B2, B3A3B3, ...B9A9B9...B 12 A 12 B 12 The polypropylene fabric consisted of 23 layers, arranged at 90° angles between the warp and weft directions. The hot-pressing conditions were: temperature 150℃, hot-pressing pressure 5 MPa, preheating time 180 s, hot-pressing time 120 s, and cooling time 600 s. The prepared polypropylene / metal composite material had a thickness of 1.75 mm, and its areal density is shown in Table 1.

[0284] Example 14

[0285] This embodiment illustrates the preparation of the polypropylene / metal composite material, polypropylene composition, three-layer co-extruded polypropylene sheet, and polypropylene fabric provided by the present invention.

[0286] (1) Preparation of polypropylene composition A:

[0287] The preparation process is the same as step (1) in Example 1.

[0288] (2) Preparation of polypropylene composition B:

[0289] The main preparation process is the same as step (2) in Example 1. The difference is that component B... i and x i The materials selected are as follows:

[0290] Components x1-x3 are random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry, Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 120℃; components x4-x6 are random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry, Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 130℃; components x7-x9 are random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry, Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 140℃; component x 10 -x 12 The random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec is an ethylene-propylene-butene terpolymer with a melting point of 150℃. Among them, the molecular weight distribution of components x1-x9, Mw / Mn, is 7-10, and the melt flow rate of components x1-x9 is 1-20g / 10min.

[0291] Finally, polypropylene composition B was obtained. i Granular material (i.e., x) i +y=B i (i = 1, 2, 3, 4, 5, 6, 7, 8, 9...12). Testing showed that the melting points of B1-B3 are 117℃, B4-B6 are 127℃, and B7-B9 are 137℃. 10 -B 12 Its melting point is 148℃.

[0292] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0293] The preparation process is the same as step (3) in Example 1.

[0294] (4) Preparation of polypropylene fabric:

[0295] The preparation process is the same as step (4) of Example 1.

[0296] (5) Preparation of polypropylene / metal composite materials:

[0297] The polypropylene fabric and metal mesh obtained in step (4) are laminated and hot-pressed together, and then cooled and shaped to form a polypropylene / metal composite material. The polypropylene / metal composite material includes 23 layers of polypropylene fabric and 1 layer of stainless steel mesh with a diameter of 0.08 mm and a mesh size of 100. The stainless steel mesh is placed in the middle of the polypropylene fabric, and 12 layers and 11 layers of polypropylene fabric are respectively placed on both sides of the stainless steel mesh. The polypropylene fabric and stainless steel mesh are stacked sequentially, from bottom to top as B 12 A 12 B 12… B9A9B 9… B3A3B3, B2A2B2, B1A1B1, stainless steel mesh, B2A2B2, B3A3B3, ...B9A9B9...B12 A 12 B 12 The polypropylene fabric consisted of 23 layers, arranged at 90° angles between the warp and weft directions. The hot-pressing conditions were: temperature 150℃, hot-pressing pressure 5 MPa, preheating time 180 s, hot-pressing time 120 s, and cooling time 600 s. The prepared polypropylene / metal composite material had a thickness of 1.72 mm, and its areal density is shown in Table 1.

[0298] Comparative Example 1

[0299] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. However, only polypropylene composition A was used for extrusion casting into a single-layer film with a thickness of 80 μm. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0300] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0301] Comparative Example 2

[0302] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. However, only polypropylene composition B was used for extrusion casting into a single-layer film with a thickness of 80 μm. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0303] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0304] Comparative Example 3

[0305] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. However, polypropylene composition A contained only component b. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0306] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0307] Comparative Example 4

[0308] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. However, polypropylene composition B contained only component y. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0309] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0310] Comparative Example 5

[0311] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. The only difference was that the thickness of film layer A accounted for 95% of the total sheet thickness. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0312] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0313] Comparative Example 6

[0314] Three-layer co-extruded polypropylene sheets were prepared according to the method of Example 1. The only difference was that the thickness of film layer A accounted for 50% of the total sheet thickness. Polypropylene fabrics and polypropylene / metal composites were also prepared according to the method of Example 1.

[0315] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 1.

[0316] Comparative Example 7

[0317] Three-layer co-extruded polypropylene sheets and polypropylene fabrics were prepared according to the method in Example 1.

[0318] Polypropylene composite materials were prepared according to the method in Example 1. Only 24 layers of polypropylene fabric were used for hot pressing. The prepared polypropylene composite material had a thickness of 1.67 mm, and its areal density is shown in Table 1.

[0319] Comparative Example 8

[0320] Co-extruded polypropylene sheets were prepared according to the method of Example 13, except that component B... i and x i The materials selected are as follows:

[0321] Component x 12 This is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 110℃; component x 11 This is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec. It is an ethylene-propylene-butene terpolymer with a melting point of 115℃; component x 10Component x9 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 120℃; Component x8 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 125℃; Component x8 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 130℃; Component x7 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 135℃; Component x6 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 138℃; Component x5 ...25℃; Component x8 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 130℃; Component x7 is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene The random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry is an ethylene-propylene-butene terpolymer with a melting point of 140℃; component x4 is a random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, an ethylene-propylene-butene terpolymer with a melting point of 143℃; component x3 is a random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, an ethylene-propylene-butene terpolymer with a melting point of 145℃; component x2 is a random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, an ethylene-propylene-butene terpolymer with a melting point of 148℃; component x1 is a random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, an ethylene-propylene-butene terpolymer with a melting point of 150℃; wherein, components x1-x 12 The molecular weight distribution Mw / Mn is between 7 and 10, and the components x1-x 12 The melt flow rates are all between 1 and 20 g / 10 min.

[0322] Finally, polypropylene composition B was obtained. i Granular material (i.e., x) i +y=B i (i = 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12), after testing, B 12 The melting point of B is 110℃. 11 The melting point of B is 113℃. 10 The melting point of B1 is 117℃, that of B9 is 123℃, that of B8 is 127℃, that of B7 is 133℃, that of B6 is 135℃, that of B5 is 137℃, that of B4 is 140℃, that of B3 is 142℃, that of B2 is 146℃, and that of B1 is 148℃.

[0323] Polypropylene fabrics and polypropylene / metal composites were prepared according to the method of Example 13.

[0324] The thickness of the prepared polypropylene / metal composite material is similar to that of Example 13.

[0325] Experimental Example

[0326] The polypropylene / metal composite materials obtained in the above examples and comparative examples were tested according to the following methods, and the test results are shown in Table 1.

[0327] (1) Tensile strength: Samples were prepared and tested according to the methods specified in GB / T1040.1-2018;

[0328] (2) Interlayer peel strength: Samples were prepared and measured in accordance with the method specified in QB / T2358-98.

[0329] (3) Drop hammer impact strength: The test was conducted according to the method specified in GB / T14153-1993. Among them, the thickness of the polypropylene / metal composite materials obtained in Examples 1-11 and Comparative Examples 1-6 were all similar, around 1.7 mm, and all within the range of 1.7 mm ± 1 mm.

[0330] Table 1

[0331]

[0332]

[0333] The results from the examples in Table 1 show that the longitudinal (MD) tensile strength of the polypropylene / metal composite material described in this invention is ≥280 MPa, and the interlaminar peel strength is ≥1 N / mm. When the polypropylene / metal composite material is obtained by hot-pressing 24 layers of polypropylene fabric and 1 layer of metal mesh, and the thickness is approximately 1.79 mm, the drop hammer impact strength is ≥280 J. Therefore, the polypropylene / metal composite material prepared according to this invention possesses both excellent tensile and impact resistance, and also exhibits good interlaminar peel strength at a relatively low hot-pressing temperature.

[0334] As can be seen from the preferred embodiments 1-3, the longitudinal (MD) tensile strength of the polypropylene / metal composite material prepared by the present invention is ≥300 MPa, and the interlaminar peel strength is ≥1.1 N / mm; the polypropylene / metal composite material is obtained by hot pressing 24 layers of polypropylene fabric and 1 layer of metal mesh, and when the thickness is about 1.79 mm, the drop hammer impact strength is ≥300 J.

[0335] As can be seen from Comparative Examples 1-6, using only a single-layer sheet structure or using interlayer ratios outside the scope of the examples will lead to a decrease in the performance of the laminated polypropylene sheets or fabrics, resulting in a significant decrease in the tensile strength, impact properties, or interlayer peel strength of the obtained polypropylene / metal composite material.

[0336] As can be seen from Comparative Example 7, polypropylene composite materials prepared by laminating and hot-pressing polypropylene sheets or fabrics alone do not achieve the tensile strength and impact performance of polypropylene / metal composite materials.

[0337] As can be seen from the more preferred embodiments 13 and 14, the present invention provides a composite material with a melting point gradient structure of polypropylene composite matrix combined with metal by designing a melting point gradient structure of laminated polypropylene sheets in a polypropylene composite matrix. This polypropylene / metal composite material has further improved tensile properties and impact resistance, and also has further improved interlaminar peel strength at a lower hot pressing temperature.

[0338] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0339] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A polypropylene / metal composite material having a laminated structure, comprising at least one metal material layer and a plurality of corresponding polypropylene coating layers covering each metal material layer, wherein the metal material layer has a plurality of through holes distributed thereon; Each polypropylene coating layer may be identical or different, and each comprises at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from the polypropylene sheet; wherein... The polypropylene sheet includes layer A and layers B and B' located on both sides of layer A, with a structure of BAB'. Layer A contains a polypropylene composition A, which includes homopolymer polypropylene a and impact copolymer polypropylene b; Layer B may be the same as or different from Layer B', and each contains a polypropylene composition B and a polypropylene composition B', wherein each of the polypropylene composition B and the polypropylene composition B' includes random copolymer polypropylene x and thermal bonding reinforcing agent y. The melting point of polypropylene composition A is greater than that of polypropylene composition B and polypropylene composition B'.

2. The polypropylene / metal composite material according to claim 1, characterized in that: The polypropylene fabric has a three-dimensional structure of plain weave, twill weave, and / or satin weave; and / or, Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 50-99 wt% homopolymer polypropylene a, 1-50 wt% impact copolymer polypropylene b; and / or, Based on the total weight of the polypropylene compositions B and B', each of the polypropylene compositions B and B' comprises 70-99 wt% random copolymer polypropylene x and 1-30 wt% thermal bonding reinforcing agent y.

3. The polypropylene / metal composite material according to claim 1, characterized in that: Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 70-90 wt% homopolymer polypropylene a, 10-30 wt% impact copolymer polypropylene b; and / or, Based on the total weight of the polypropylene compositions B and B', each of the polypropylene compositions B and B' comprises 80-90 wt% random copolymer polypropylene x and 10-20 wt% thermal bonding enhancer y.

4. The polypropylene / metal composite material according to claim 1, characterized in that: Based on the total thickness of the polypropylene sheet, the thickness of layer A accounts for 51%-89% of the total thickness; and / or, The melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in each of the polypropylene compositions B and B'.

5. The polypropylene / metal composite material according to claim 1, characterized in that: Based on the total thickness of the polypropylene sheet, the thickness of layer A accounts for 71%-89% of the total thickness; and / or, The melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in each of the polypropylene compositions B and B', and the temperature difference between the corresponding melting points is greater than or equal to 10 degrees.

6. The polypropylene / metal composite material according to claim 1, characterized in that: Based on the total thickness of the polypropylene sheet, the thickness of layer A accounts for 71%-80% of the total thickness.

7. The polypropylene / metal composite material according to claim 1, characterized in that: The homopolymer polypropylene a has a melting point of 160-170℃; and / or, The homopolymer polypropylene a has a melt flow rate of 0.5-50 g / 10 min at 230 °C and 2.16 kg load; and / or, The isotacticity of the homopolymer polypropylene a is not less than 96%.

8. The polypropylene / metal composite material according to claim 1, characterized in that: The homopolymer polypropylene a has a melt flow rate of 1-20 g / 10 min at 230 °C and 2.16 kg load.

9. The polypropylene / metal composite material according to claim 1, characterized in that: The homopolymer polypropylene a has a melt flow rate of 2.5-18 g / 10 min at 230 °C and 2.16 kg load.

10. The polypropylene / metal composite material according to claim 1, characterized in that: The impact-resistant copolymer polypropylene b has a melting point of 150-170℃; and / or, The impact-resistant copolymer polypropylene b is copolymerized with propylene using ethylene or butene as the monomer, with an ethylene or butene content of 2-50% wt, and / or... The impact-resistant copolymer polypropylene b has a melt flow rate of 0.5-50 g / 10 min at 230°C and 2.16 kg load; and / or, The impact strength of the impact-resistant copolymer polypropylene b is not less than 20 KJ / m. 2 .

11. The polypropylene / metal composite material according to claim 1, characterized in that: The monomer for the copolymerization of the impact-resistant polypropylene b and propylene is ethylene or butene, with an ethylene or butene content of 3-20% wt; and / or, The impact-resistant copolymer polypropylene b has a melt flow rate of 1-20 g / 10 min at 230°C and 2.16 kg load.

12. The polypropylene / metal composite material according to claim 1, characterized in that: The impact-resistant copolymer polypropylene b is copolymerized with propylene using ethylene or butene as the monomer, with an ethylene or butene content of 5-15% wt, and / or... The impact-resistant copolymer polypropylene b has a melt flow rate of 2.5-18 g / 10 min at 230°C and 2.16 kg load.

13. The polypropylene / metal composite material according to claim 1, characterized in that: The random copolymer polypropylene x has a melting point of 120-140℃; and / or, The random copolymer polypropylene x has a melt flow rate of 0.5-50 g / 10 min at 230 °C and 2.16 kg load; and / or, The random copolymer polypropylene x is a copolymer of propylene with ethylene and / or butene.

14. The polypropylene / metal composite material according to claim 1, characterized in that: The random copolymer polypropylene x has a melt flow rate of 1-20 g / 10 min at 230 °C and 2.16 kg load; and / or, The random copolymer polypropylene x is an ethylene-propylene-butene terpolymer or a propylene-ethylene binary copolymer.

15. The polypropylene / metal composite material according to claim 1, characterized in that: The random copolymer polypropylene x has a melt flow rate of 3-18 g / 10 min at 230 °C and 2.16 kg load.

16. The polypropylene / metal composite material according to claim 1, characterized in that: The melt flow rate of the heat-bonding reinforcing agent y at 190°C and 2.16 kg load is 0.5-50 g / 10 min.

17. The polypropylene / metal composite material according to claim 1, characterized in that: The melt flow rate of the heat-bonding reinforcing agent y at 190°C and 2.16 kg load is 1-20 g / 10 min.

18. The polypropylene / metal composite material according to claim 1, characterized in that: The melt flow rate of the thermal bonding enhancer y at 190°C and 2.16 kg load is 1-18 g / 10 min.

19. The polypropylene / metal composite material according to claim 1, characterized in that: The heat-bonding reinforcing agent y is selected from one or more of polyolefin elastomers, ethylene propylene diene monomer (EPDM) rubber, SEBS, SBS, EVA, and petroleum resins.

20. The polypropylene / metal composite material according to claim 19, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene with propylene and / or α-olefins.

21. The polypropylene / metal composite material according to claim 20, characterized in that: The α-olefin is a C4-C12 α-olefin.

22. The polypropylene / metal composite material according to claim 20, characterized in that: The α-olefin is 1-butene and / or 1-octene.

23. The polypropylene / metal composite material according to claim 19, characterized in that: The petroleum resin is a hydrogenated petroleum resin of C5 and / or C9.

24. The polypropylene / metal composite material according to claim 19, characterized in that: The petroleum resin is a C5 and / or C9 hydrogenated petroleum resin with a softening point of 100-150℃.

25. The polypropylene / metal composite material according to claim 19, characterized in that: The petroleum resin is a cyclopentadiene type resin.

26. The polypropylene / metal composite material according to claim 1, characterized in that: Layer A also contains a β-crystal nucleating agent.

27. The polypropylene / metal composite material according to claim 26, characterized in that: The β-crystal nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, group IIA binary complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylate nucleating agents; and / or, Based on a total amount of 100 parts by weight of the polypropylene composition A, the content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight.

28. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The BAB' layered structure of the polypropylene sheet is obtained by co-extrusion of components including polypropylene composition A and polypropylene compositions B and B'.

29. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The polypropylene / metal composite material is prepared by sequentially stacking multiple layers of polypropylene sheets and / or polypropylene fabrics with the metal material layer, hot-pressing and fusing them, and then cooling and shaping them.

30. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The total number of layers of the polypropylene sheet and / or polypropylene fabric is greater than or equal to 2; and / or, The areal density of the polypropylene / metal composite material is greater than or equal to 600 g / m³. 2 ; and / or, The longitudinal tensile strength of the polypropylene / metal composite material is greater than or equal to 280 MPa.

31. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The total number of layers of the polypropylene sheet and / or polypropylene fabric is 2-200 layers; and / or, The areal density of the polypropylene / metal composite material is 600-35000 g / m³. 2 ; and / or, The longitudinal tensile strength of the polypropylene / metal composite material is greater than or equal to 300 MPa.

32. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The total number of layers of the polypropylene sheet and / or polypropylene fabric is 4-100 layers; and / or, The areal density of the polypropylene / metal composite material is 800-12000 g / m³. 2 .

33. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The metal material layer is a metal mesh.

34. The polypropylene / metal composite material according to claim 33, characterized in that: The metal mesh is selected from alloy mesh.

35. The polypropylene / metal composite material according to claim 33, characterized in that: The metal mesh is selected from at least one of stainless steel mesh, carbon steel mesh, and galvanized steel mesh.

36. The polypropylene / metal composite material according to claim 33, characterized in that: The diameter of the metal wires in the metal mesh is 0.02-2 mm; and / or, the number of holes is 10-1000 mesh; and / or, The number of layers of the metal material is greater than or equal to 1.

37. The polypropylene / metal composite material according to claim 33, characterized in that: The diameter of the metal wires in the metal mesh is 0.03-1 mm; and / or, the number of holes is 50-500 mesh; and / or, The number of metal material layers is 1-50.

38. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The number of metal material layers is 1-20.

39. The polypropylene / metal composite material according to any one of claims 1-27, characterized in that: The polypropylene / metal composite material includes a polypropylene composite matrix formed by stacking all polypropylene coating layers and at least one metal material layer disposed in the polypropylene composite matrix; The polypropylene composite matrix comprises multiple sequentially stacked polypropylene sheet unit groups; each polypropylene sheet unit group includes at least one identical or different polypropylene sheet unit, and each polypropylene sheet unit includes a core layer A. i and located in core layer A i Outer B on both sides i B' i The structure is B i A i B' i The structure of the polypropylene composite material, from bottom to top, is group n...group i...group 2, group 1, group 2...group i...group n, and the total number of polypropylene sheet unit groups is 2n-1. Both i and n are integers not less than 2, and i ≤ n; Among them, the core layer A in the polypropylene sheet unit i Composition A containing polypropylene i Outer layer B i With outer layer B' i Whether the composition is the same or different, each composition corresponds to a polypropylene composition B. i Polypropylene composition B' i , The polypropylene composition A i The melting point is greater than that of the polypropylene composition B. i The polypropylene composition B' i The melting point of the outermost layer in the i-th group is greater than or equal to the average melting point of the outermost layer in the (i-1)-th group.

40. The polypropylene / metal composite material according to claim 39, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 5°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group (i-1) is the same or different, and each is between 1 and 40°C; and / or, 2≤n≤100; and / or, Each polypropylene sheet unit group, independently, comprises 1 to 10 identical or different polypropylene sheet units; and / or, The number of polypropylene sheet units on both sides of each of the metal material layers is approximately equal.

41. The polypropylene / metal composite material according to claim 39, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 10°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group (i-1) is the same or different, each ranging from 1 to 10 °C; and / or, 2≤n≤50; and / or, Each polypropylene sheet unit group, independently, comprises 1 to 5 identical or different polypropylene sheet units.

42. The polypropylene / metal composite material according to claim 39, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 20°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group i-1, whether the difference is the same or different, is 1-5℃.

43. A method for preparing a polypropylene / metal composite material according to any one of claims 1-42, comprising sequentially stacking multiple layers of the polypropylene sheets and / or polypropylene fabrics with the metal material layer, hot-pressing and fusing them, and then cooling and shaping them to obtain the polypropylene / metal composite material.

44. The preparation method according to claim 43, characterized in that: The multilayer polypropylene sheets are stacked from top to bottom at 0-90° angles along their respective machine directions; and / or, The multilayer polypropylene fabric is arranged from top to bottom in a 0-90° arrangement between warp directions; and / or, The total number of layers in the multilayer polypropylene sheet and / or multilayer polypropylene fabric is greater than or equal to 2; and / or, The number of layers of the metal material is greater than or equal to 1.

45. The preparation method according to claim 43, characterized in that: The total number of layers in the multilayer polypropylene sheets and / or multilayer polypropylene fabrics is 2-200; and / or, The number of metal material layers is 1-50.

46. ​​The preparation method according to claim 43, characterized in that: The total number of layers in the multilayer polypropylene sheet and / or multilayer polypropylene fabric is 4-100; and / or, The number of metal material layers is 1-20.

47. The preparation method according to claim 43, characterized in that: The hot-pressing fusion temperature is 115-170℃; and / or, The pressure for the hot-pressing fusion is 2-10 MPa; and / or, The preheating time for the hot-pressing fusion is 5-600s, and the hot-pressing time is 1-600s; and / or, The cooling and shaping pressure is 2-8 MPa, and the cooling and shaping time is 30-700 seconds.

48. The preparation method according to claim 43, characterized in that: The hot-pressing fusion temperature is 115-159℃; and / or, The preheating time for hot-pressing fusion is 5-600s, and the hot-pressing time is 10-500s.

49. The preparation method according to claim 43, characterized in that: The temperature for hot pressing and fusion is 140-159℃.

50. The application of the polypropylene / metal composite material according to any one of claims 1-42 and the polypropylene / metal composite material prepared by the preparation method according to any one of claims 43-49 in the fields of automobile manufacturing, military materials and consumer products.

51. The application according to claim 50, characterized in that: The consumer products mentioned are for sports protection.

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