Low temperature high impact high strength polypropylene sheet and fabric therefrom, polypropylene composite material and method of manufacture and use thereof

Abstract

This invention relates to the field of polypropylene materials, and more specifically, to a low-temperature high-impact, high-strength polypropylene sheet and its fabric, polypropylene composite materials, and their manufacturing methods and applications. The impact-resistant polypropylene sheet has a structure of BAB'; polypropylene composition A contains homopolymer polypropylene a and toughening agent m; polypropylene compositions B and B' each contain random copolymer polypropylene x and toughening agent n; wherein the melting point of polypropylene composition A is higher than the melting points of polypropylene composition B and polypropylene composition B'; the toughening agents m and n may be the same or different, and are each selected from elastic materials. The polypropylene composite material obtained by laminating this impact-resistant polypropylene sheet exhibits excellent rigidity and low-temperature impact resistance, and maintains high interlaminar peel strength even at lower hot-pressing temperatures and over a wider hot-pressing temperature range.

Description

Technical Field

[0001] This invention relates to the field of polypropylene materials, and more specifically, to a low-temperature high-impact high-strength polypropylene sheet and its fabric, polypropylene composite materials, and their preparation methods and applications. Background Technology

[0002] Polypropylene (PP) resin is currently the most widely used synthetic resin material. It has advantages such as low density and low cost, as well as good mechanical properties, processing properties and weldability.

[0003] Self-reinforced polymer composites can further enhance the usability of high-performance materials. They are generally composed of a matrix and a reinforcing phase of the same polymer but with different morphologies. The reinforcing phase is usually highly oriented fibers or ribbons. Hot pressing is a common method for preparing self-reinforced polymer composites. Its working principle is that when the reinforcing phase is hot-pressed under certain temperature and pressure, the surface of the reinforcing phase fibers melts and becomes the matrix melt. The matrix melt and the surface of the reinforcing phase co-crystallize during melting, thereby providing sufficient interfacial bonding strength. For example, US Patent (US6312638B1) describes hot-pressing melt-spun oriented polyolefin fibers to prepare polyolefin boards by partially melting and bonding the substrate surface under specific temperature and pressure. However, this preparation method has drawbacks such as high hot-pressing temperature and sensitivity to hot-pressing temperature. Furthermore, the oriented fibers undergo significant deorbiting after hot pressing, resulting in a significant decrease in the mechanical strength of the material.

[0004] Compared to the methods described above, US Patent (US8133537B2) describes a method for hot-pressing three layers of polyolefin fibers with different melting points to obtain a polyolefin composite material, wherein the melting temperature of the first and second polyolefin layers is lower than that of the core layer. This method broadens the hot-pressing processing window, reduces the hot-pressing pressure, and can complete the hot-pressing molding of polyolefins with different melting points. However, the resulting hot-pressed composite material has lower impact strength and interlaminar peel strength.

[0005] Polypropylene, as a crystalline material, exhibits certain impact resistance due to the movement of its amorphous chain segments at room temperature (23℃). However, at low temperatures, the movement of molecular chains is restricted, preventing the effective release of impact energy. Therefore, due to its inherent structure and properties, polypropylene is prone to brittleness and poor toughness at low temperatures. These problems severely limit the application of polypropylene, especially its high-end applications in specialized low-temperature fields. Current technologies (CN114369315A, CN114409998A, CN 110698769 B, CN 114262486 A) primarily improve the low-temperature impact resistance of composite materials through melt blending modification of PP with elastomers. This method is the most common way to improve the low-temperature impact resistance of materials; however, it significantly reduces the rigidity and modulus of the composite material, failing to meet the requirements of high-performance materials that are both rigid and tough at low temperatures.

[0006] Therefore, overcoming the application bottleneck that polypropylene itself is prone to brittleness and has poor toughness under extreme conditions such as low temperature, and providing a polypropylene composite material that simultaneously has high strength, interlaminar peel strength and low temperature impact performance is a technical problem that needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to overcome the technical shortcomings of existing polypropylene composite materials, which are difficult to simultaneously possess high strength, interlaminar peel strength, and low-temperature impact resistance. To further improve the comprehensive mechanical properties of polypropylene materials, achieve high performance, and broaden their application fields, especially to overcome the bottleneck of polypropylene's inherent tendency to become brittle and have poor toughness under extreme conditions such as low temperatures, this invention provides a low-temperature high-impact, high-strength polypropylene sheet and its fabric, a polypropylene composite material, and its preparation and application. The high-strength, low-temperature, high-impact polypropylene sheet of this invention is obtained through hot pressing and other processes to produce a high-strength, low-temperature, high-impact polypropylene composite material. This high-strength, low-temperature, high-impact polypropylene composite material exhibits excellent rigidity and low-temperature impact resistance. Even at lower hot-pressing temperatures and within a wider hot-pressing temperature range, the interlaminar peel strength of the obtained high-strength, high-low-temperature, high-impact polypropylene composite material remains high.

[0008] The first aspect of the present invention is to provide an impact-resistant polypropylene sheet, comprising layer A and layers B and B' located on both sides of layer A, having a structure of BAB';

[0009] Layer A contains a polypropylene composition A, which includes homopolymer polypropylene a and toughening agent m; Layer B may be the same as or different from Layer B', and each contains a polypropylene composition B and a polypropylene composition B', which each includes random copolymer polypropylene x and toughening agent n; wherein the melting point of polypropylene composition A is greater than the melting point of polypropylene composition B and polypropylene composition B'; the toughening agent m and the toughening agent n may be the same or different, and each is selected from elastic materials.

[0010] 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 some preferred embodiments of the present invention, the thin film layers B and B' on both sides of the thin film layer A are the same.

[0011] In some preferred embodiments 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 polypropylene composition B and polypropylene composition B', and preferably the temperature difference between the corresponding melting points is greater than or equal to 10°C.

[0012] In a preferred embodiment of the present invention, the melting point of the polypropylene composition A is greater than that of the polypropylene composition B and the polypropylene composition B'; preferably, the melting point of the homopolymer polypropylene a in the polypropylene composition A is greater than that of the random copolymer polypropylene x in the polypropylene composition B and the polypropylene composition B', and preferably the temperature difference between the corresponding melting points is greater than or equal to 10 degrees.

[0013] In some preferred embodiments of the present invention, the difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B, and the difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B', are each greater than or equal to 5°C, preferably greater than or equal to 10°C. In this preferred embodiment, the inventors of the present invention have surprisingly discovered that the polypropylene sheet obtained is subjected to hot pressing and other processes to obtain a polypropylene 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 interlaminar peel strength of the obtained polypropylene composite material is higher. Furthermore, it also exhibits high impact resistance at low temperatures (down to -20°C), overcoming the technical deficiency of existing polypropylene composite materials that are difficult to simultaneously possess high strength, interlaminar peel strength, and low-temperature impact resistance.

[0014] In some preferred embodiments of the present invention, based on the total thickness of the impact-resistant polypropylene sheet, the thickness of layer A accounts for 51%-89% of the total thickness, preferably 71%-89%, and more preferably 71%-80%. The thicknesses of film layers B and B' on both sides of film layer A can be the same or different, preferably the same.

[0015] 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.

[0016] 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.

[0017] In some preferred embodiments of the present invention, based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 50-98 wt% homopolymer polypropylene a and 2-50 wt% toughening agent m; preferably, the polypropylene composition A comprises 70-90 wt% homopolymer polypropylene a and 10-30 wt% toughening agent m.

[0018] In some preferred embodiments of the present invention, based on the total weight of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 70-98 wt% random copolymer polypropylene x and 2-50 wt% toughening agent n; preferably, each of the polypropylene composition B and the polypropylene composition B' comprises 70-90 wt% random copolymer polypropylene x and 10-30 wt% toughening agent n.

[0019] In some preferred embodiments of the present invention, the homopolymer polypropylene a has the following characteristics: a melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min, at 230°C and a load of 2.16 kg; and / or an isotacticity (mm) of not less than 96%.

[0020] According to the present invention, the toughening agent m and the toughening agent n may be the same or different, and each is selected from elastic materials; preferably, the toughening agent m and the toughening agent n are each selected from elastomers and / or soft biodegradable materials. According to the present invention, more preferably, the toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or modified products of at least one of the following substances: polyolefin elastomers, ethylene propylene diene monomer (EPDM) rubber, SEBS, SBS, EVA, biodegradable polyesters, natural rubber, bio-based elastomers, and specialty rubbers; even more preferably, the toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or modified products of at least one of the following substances: polybutylene adipate terephthalate, polybutylene terephthalate succinate, polybutylene succinate and its copolymers, polycaprolactone, natural rubber, hydrogenated nitrile butadiene rubber, and polyolefin elastomers; more preferably, the toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or modified products of at least one of the following substances: polyolefin elastomers and hydrogenated nitrile butadiene rubber.

[0021] The aforementioned bio-based elastomers, as examples, can be at least one of bio-based polyurethane elastomers, bio-based polyamide elastomers, and bio-based polyester elastomers.

[0022] According to the present invention, when toughening agent m and toughening agent n each contain rubber-like materials, they are both vulcanized rubber materials.

[0023] In some further preferred embodiments of the present invention, the toughening agent m and the toughening agent n are each selected from a polyolefin elastomer maleic anhydride modified material and hydrogenated nitrile butadiene rubber; preferably, the weight ratio of the polyolefin elastomer maleic anhydride modified material and the hydrogenated nitrile butadiene rubber is 0.2-5 (i.e. (0.2-5):1); more preferably,

[0024] The polyolefin elastomer is a copolymer elastomer of ethylene with the following olefins: propylene and / or α-olefins; more preferably, the α-olefin is a C4-C12 α-olefin, and more preferably 1-butene and / or 1-octene.

[0025] According to the present invention, the maleic anhydride modified polyolefin elastomer can be prepared by existing technology or by using commercially available products. Further, more preferably, the toughening agent m and the toughening agent n are each obtained by the following method: mixing the maleic anhydride modified polyolefin elastomer with hydrogenated nitrile butadiene rubber to obtain a modified hydrogenated nitrile butadiene masterbatch; then vulcanizing the modified hydrogenated nitrile butadiene masterbatch to obtain vulcanized rubber; and finally crushing the vulcanized rubber to obtain toughening agent m and toughening agent n respectively. Specific processing conditions can be those existing in the art; the present invention is not particularly limited to these conditions, including but not limited to the methods described in the specific embodiments section of the present invention.

[0026] 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 toughening component m in the composition can better absorb impact energy, meeting the impact performance requirements, especially the impact performance requirements at low temperatures, thus giving the sheet better low-temperature impact resistance. Simultaneously, because the macromolecular chain segments in homopolymer polypropylene a are relatively regular, crystallization occurs during the sheet preparation process, resulting in better tensile properties in the sheet.

[0027] In some preferred embodiments of the present invention, the random copolymer polypropylene x has:

[0028] The melting point is 110-150℃, preferably 120-140℃; and / or, the melt flow rate at 230℃ and 2.16kg load is 0.5-50g / 10min, preferably 1-20g / 10min, more preferably 3-18g / 10min; and / or, the molecular weight distribution Mw / Mn is 5-12, preferably 7-10; and / or, it is a copolymer of propylene and ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene binary copolymer.

[0029] According to the inventor's research, when polypropylene composition B 、 When the melt flow rate and polymer composition ratio of B' are within the preferred range, the low melting point random copolymer polypropylene x and toughening agent n in the composition can significantly reduce the hot pressing temperature and widen the hot pressing temperature window. Furthermore, the toughening agent n is a single-component multifunctional additive that provides good adhesion to the sheet, further improves the interlayer peel strength, and significantly enhances the low-temperature impact resistance of the sheet.

[0030] In some preferred embodiments of the present invention, layer A further contains a β-crystal nucleating agent; preferably,

[0031] The β-crystal nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, group IIA two-component complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylate nucleating agents.

[0032] The selection range of the content of the β-crystal nucleating agent is relatively wide. Preferably, the content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight relative to 100 parts by weight of polypropylene composition A.

[0033] According to the inventors' research, when the melting point difference, polymer composition ratio, and thickness distribution of film layer A of polypropylene composition A, polypropylene composition B, and polypropylene composition B' are within the preferred range, the sheet preparation process can be made more stable, thereby giving the sheet better uniformity, tensile strength, impact performance, and interlayer peel strength.

[0034] In some preferred embodiments of the present invention, the BAB' layer structure of the polypropylene sheet can be prepared by various methods. In one preferred embodiment of the present invention, the BAB' layer structure of the impact-resistant polypropylene sheet is obtained by co-extrusion of layer A raw material containing polypropylene composition A, layer B raw material containing polypropylene composition B, and layer B' raw material containing polypropylene composition B'.

[0035] The second aspect of the present invention is to provide a method for preparing the impact-resistant polypropylene sheet described in the first aspect, comprising co-extruding, casting or calendering, and stretching a layer A raw material containing a polypropylene composition A, a layer B raw material containing a polypropylene composition B, and a layer B' raw material containing a polypropylene composition B' according to a BAB' structure to obtain the impact-resistant polypropylene sheet.

[0036] In some preferred embodiments of the present invention, the preparation of the raw material for layer A includes melt blending of components including the homopolymer polypropylene a and the toughening agent m. The melt blending conditions and equipment for the polypropylene composition A adopt those of prior art polyolefin melt blending. For example, the melt temperature can be 130-168°C, and the preferred equipment is a twin-screw extruder.

[0037] In some preferred embodiments of the present invention, the preparation of the raw materials for layers B and B' includes melt blending of each component, including the random copolymer polypropylene x and the toughening agent n. The melt blending conditions and equipment for layers B and B' adopt the conditions and equipment for melt blending of polyolefins in the prior art. For example, the melting temperature can be 100-148°C, and the preferred equipment is a twin-screw extruder.

[0038] In some preferred embodiments of the present invention, the temperatures of the co-extrusion and casting are each independently selected from 200-240°C.

[0039] In some preferred embodiments of the present invention, the rolling temperature is 50-70°C.

[0040] 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.

[0041] The specific process for preparing thin films by extrusion calendering is a commonly used method in this field and will not be described in detail here.

[0042] A third aspect of the present invention is to provide an impact-resistant polypropylene fabric, a three-dimensional polypropylene fabric obtained by weaving the impact-resistant polypropylene sheet described in the first aspect; preferably, the impact-resistant polypropylene fabric is obtained by slitting and weaving the impact-resistant polypropylene sheet; and / or, the impact-resistant polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0043] To facilitate weaving, it is preferable to cut the polypropylene sheet into polypropylene sheets with a width of 2-5mm, and then weave them into polypropylene fabric.

[0044] In a more preferred embodiment of the present invention, the polypropylene fabric is a plain weave, twill weave, satin weave, or three-dimensional polypropylene fabric obtained by weaving a three-layer co-extruded polypropylene stretch flat strip, and the three-layer co-extruded polypropylene stretch flat strip includes at least one film layer A formed by a high-melting-point polypropylene composition A and at least one film layer B formed by a low-melting-point polypropylene composition B, wherein the polypropylene composition A includes homopolymer polypropylene a and toughening agent m; the polypropylene composition B includes random copolymer polypropylene x and toughening agent n, and the polymer film layer B is located on both sides of layer A, and may be the same or different.

[0045] A fourth aspect of the present invention is to provide an impact-resistant polypropylene composite material, said impact-resistant polypropylene composite material being prepared by hot pressing together multiple layers of impact-resistant polypropylene sheets as described in the first aspect and / or impact-resistant polypropylene fabrics as described in the third aspect.

[0046] Preferably, the impact-resistant polypropylene composite material is prepared by hot pressing multiple layers of the impact-resistant polypropylene sheets or the impact-resistant polypropylene fabric.

[0047] Preferably, the multi-layer impact-resistant polypropylene sheets are stacked from top to bottom at an angle of 0-90° along their respective machine directions.

[0048] Preferably, the multilayer impact-resistant polypropylene fabric is stacked from top to bottom with the warp direction placed at an angle of 0-90° between the warp directions.

[0049] Preferably, the multilayer impact-resistant polypropylene sheet and / or multilayer impact-resistant polypropylene fabric has more than or equal to 2 layers, more preferably 2-200 layers; and most preferably 4-100 layers.

[0050] In some preferred embodiments of the present invention, the impact-resistant polypropylene composite material comprises a plurality of 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 iA i B' i The structure of the impact-resistant polypropylene composite material is arranged from bottom to top as 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;

[0051] 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 ,

[0052] 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 the average melting point of the outermost layer in the (i-1)-th group.

[0053] According to the present invention, in the structure of the polypropylene composite material, the upper i-th group and the lower i-th group may be the same or different.

[0054] In a 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' i The difference in melting point 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.

[0055] According to the present invention, the core layer in each polypropylene sheet unit can be the same material or different materials. The present invention does not impose any particular limitation on this, as long as A... i The melting point is greater than that of the polypropylene composition B. i Polypropylene composition B' i The melting points of all these factors can achieve better technical results.

[0056] In a preferred embodiment of the present invention, the difference between the average melting point of all outer layers in the i-th group and the average melting point of all outer layers in the (i-1)-th group is the same or different, and is 1-40°C, preferably 1-10°C, and more preferably 1-5°C.

[0057] According to the present invention, the total number of polypropylene sheet unit groups is 2n-1. The present invention has a wide range of options for the total number of polypropylene sheet unit groups. In a preferred embodiment of the present invention, 2≤n≤100, more preferably, 2≤n≤50, and even more preferably, 2≤n≤30.

[0058] 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.

[0059] Preferably, but not necessarily, the melting point of any outer layer in each group is within ±10°C, ±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.

[0060] 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.

[0061] 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 ...B ip 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.

[0062] In a preferred embodiment of the present invention, the polypropylene composite material has at least one of the following characteristics:

[0063] Longitudinal tensile strength ≥130MPa, preferably ≥160MPa;

[0064] Interlayer peel strength ≥1N / mm, preferably ≥1.2N / mm;

[0065] 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.

[0066] When the polypropylene composite material is obtained by hot pressing 24 layers of polypropylene fabric and the thickness is about 1.6 mm, the drop hammer impact strength at -20℃ is ≥160 J, preferably ≥180 J.

[0067] 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.

[0068] A fifth aspect of the present invention is to provide a method for preparing the impact-resistant polypropylene composite material described in the fourth aspect, the method comprising hot-pressing and fusing the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric into a laminate, and then cooling and shaping it to form the impact-resistant polypropylene composite material.

[0069] Preferably, the temperature of the hot-pressing fusion is 115-170℃, more preferably 115-159℃, and even more preferably 140-159℃.

[0070] Preferably, the pressure of the hot-press fusion is 2-10 MPa.

[0071] Preferably, the preheating time for hot pressing fusion is 5-600s, and the hot pressing time is 1-600s, preferably 10-500s.

[0072] Preferably, the cooling and shaping pressure is 2-8 MPa, and the cooling and shaping time is 30-700 s.

[0073] Preferably, the number of layers of the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric stack is greater than or equal to 2 layers, more preferably 2-200 layers; more preferably 4-100 layers.

[0074] Preferably, adjacent layers of the impact-resistant polypropylene fabric stack are placed at an angle of 0-90° between the warp and weft directions.

[0075] Preferably, adjacent layers of the impact-resistant polypropylene sheet stack are placed at 0-90° along their respective machine directions.

[0076] In a more preferred embodiment of the present invention, the method for preparing the high-strength, high-impact polypropylene composite material includes the following steps:

[0077] Step a: Polypropylene composition A, polypropylene composition B, and polypropylene composition 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℃, and the temperature of the calendering roll is 50-70℃.

[0078] Step b: The polypropylene co-extruded sheet is stretched at a certain temperature to obtain a polypropylene stretched sheet; the stretching method is free stretching, and / or solid-phase stretching, and / or multi-stage stretching; the stretching temperature is preferably 90-165℃, more preferably 90-140℃, and even more preferably 90-119℃; the stretching ratio is 1-20 times, preferably 2-15 times.

[0079] 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.

[0080] Step d: The polypropylene fabrics are sequentially stacked and hot-pressed together, and then cooled and shaped to form a polypropylene 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 2-10MPa, preheating time 5-600s, hot-pressing time 1-600s, preferably 10-500s, cooling pressure 2-8MPa, cooling time 30-700s; preferably, adjacent polypropylene fabrics in the polypropylene composite material can be placed at 0-90° between the warp and weft directions.

[0081] 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.

[0082] 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.

[0083] In the preparation process, the polypropylene sheets and / or polypropylene fabrics are sequentially stacked 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 to produce a polypropylene composite material, i.e., a stacked hot-pressed product. Afterwards, 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 when the aforementioned preparation equipment is used to prepare the polymer composite material, the polymer composite material exhibits better tensile strength, impact performance, and interlaminar peel strength.

[0084] The sixth aspect of the present invention is to provide the application of the impact-resistant polypropylene sheet described in the first aspect, the impact-resistant polypropylene fabric described in the third aspect, the impact-resistant polypropylene composite material described in the fourth aspect, and the impact-resistant polypropylene composite material prepared by the preparation method described in the fifth aspect in the fields of electrical component packaging, automobile manufacturing, military materials, and consumer products.

[0085] According to specific embodiments of the present invention, the materials field includes the electrical and electronic industry, 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.

[0086] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0087] (1) The high-strength, high-low temperature impact-resistant polypropylene composite material of the present invention has excellent rigidity, low-temperature impact resistance and interlayer peeling performance. Through component design, especially the temperature difference of the melting point of the composition in the sheet, the material performance is realized, the application field of polypropylene is broadened, and in particular, the bottleneck of polypropylene itself is that it is very easy to become brittle and has poor toughness under extreme conditions such as low temperature is overcome.

[0088] The polypropylene composite material has the following characteristics:

[0089] Longitudinal (MD) tensile strength ≥130MPa, preferably ≥160MPa; interlaminar peel strength ≥1N / mm, preferably ≥1.2N / mm; when the composite material is made of only 24 layers of polypropylene fabric hot-pressed together and the thickness is about 1.6mm, the -20℃ drop hammer impact strength ≥160J, preferably ≥180J.

[0090] (2) The polypropylene 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 caused by high temperature operation. At the same time, it still has good interlayer peel strength when prepared at a lower hot pressing temperature.

[0091] (3) This preparation method can reduce the hot pressing operation time, while improving production efficiency and reducing production energy consumption.

[0092] (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

[0093] 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.

[0094] In the following embodiments and comparative examples:

[0095] The extrusion calender and solid phase stretching equipment were purchased from Tianjin Hengrui Company, and the model is HRPC-800 three-layer co-extrusion plastic stretching sheet production line.

[0096] The properties of the polypropylene composition and sheet were tested according to the following methods, and the film test results are shown in Table 1:

[0097] (1) Melt mass flow rate (MFR): The test shall be performed in accordance with the method specified in GB / T 3682-2000, wherein the test temperature is 230℃ and the load is 2.16kg;

[0098] (2) Melting point, determined according to the method specified in GB / T 28724-2012;

[0099] (3) Tensile strength: determined according to the method specified in GB / T1040.1-2018;

[0100] (4) Low temperature (-20℃) drop hammer impact strength: determined according to the method specified in GB / T14153-1993;

[0101] (5) Interlayer peel strength: determined according to the method specified in QB / T2358-98;

[0102] (6) Maleic anhydride grafted ethylene-octene copolymer (POE-g-MAH): CMG5805-L, Jia Yirong Company.

[0103] (7) Hydrogenated nitrile butadiene rubber (HNBR): saturation of 99%, acrylonitrile content of 36%, Mooney viscosity of 65, Zeon Corporation, Japan.

[0104] (8) Mixed toughening agent 1#: hydrogenated nitrile rubber: POE-g-MAH = 80:20 (weight ratio). Preparation method is as follows:

[0105] a. Add 20 parts by weight of POE-g-MAH to a mixer and melt it at 180°C. Then add 80 parts by weight of hydrogenated nitrile butadiene rubber and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0106] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 40 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 1 part by weight of antioxidant RD (Ningkang Chemical), 8 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 2 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0107] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 1#.

[0108] (9) Mixed toughening agent 2#: hydrogenated nitrile butadiene rubber: POE-g-MAH = 50:50 (weight ratio). Preparation method is as follows:

[0109] a. Add 50 parts by weight of POE-g-MAH to a mixer and melt it at 180°C. Then add 50 parts by weight of hydrogenated nitrile butadiene rubber and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0110] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 2.5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 25 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 1 part by weight of antioxidant RD (Ningkang Chemical), 5 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 1.25 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0111] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 2#.

[0112] (10) Mixed toughening agent 3#: hydrogenated nitrile rubber: POE-g-MAH = 20:80 (weight ratio). Preparation method is as follows:

[0113] a. Add 80 parts by weight of POE-g-MAH to a mixer and melt it at 180°C. Then add 20 parts by weight of hydrogenated nitrile butadiene rubber and 0.1 parts by weight of antioxidant RD (Ningkang Chemical). Stir at 50 r / min and mix for 5 minutes to obtain modified hydrogenated nitrile butadiene masterbatch.

[0114] b. Modified hydrogenated nitrile butadiene masterbatch was prepared into vulcanized rubber using ordinary rubber processing technology: 100 parts by weight of modified hydrogenated nitrile butadiene masterbatch, 1 part by weight of zinc oxide (Beijing Inokai), 0.5 parts by weight of stearic acid (Beijing Inokai), 10 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 0.5 parts by weight of antioxidant RD (Ningkang Chemical), 2 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 0.5 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in an internal mixer and then vulcanized in an ordinary flat vulcanizing machine at 180℃ for 10 minutes.

[0115] c. Vulcanized rubber is physically crushed to obtain mixed toughening agent 3#.

[0116] (11) Hydrogenated butadiene-acrylonitrile rubber, prepared by the following method:

[0117] Hydrogenated nitrile butadiene rubber (NBR) was prepared using a conventional rubber processing method: 100 parts by weight of hydrogenated NBR masterbatch (99% saturation, 36% acrylonitrile content, Mooney viscosity 65, from Zeon Corporation, Japan), 5 parts by weight of zinc oxide (Beijing Inokai), 1 part by weight of stearic acid (Beijing Inokai), 50 parts by weight of N-220 carbon black (Tianjin Baochi Chemical), 2 parts by weight of antioxidant RD (Ningkang Chemical), 8 parts by weight of peroxide vulcanizing agent F-40 (Beijing Inokai), and 2 parts by weight of triallyl isocyanate (co-vulcanizing agent, Beijing Inokai) were mixed in a Banbury mixer, then vulcanized in a conventional flat vulcanizing machine at 180℃ for 10 minutes, and finally physically crushed to obtain hydrogenated NBR.

[0118] (12) In the following examples, the β-crystal nucleating agent with the brand name VP101B was sourced from the Beijing Research Institute of Chemical Industry of 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.

[0119] Example 1

[0120] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0121] (1) Preparation of polypropylene composition A:

[0122] Component a is homopolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 160℃, a melt flow rate of 3.2g / 10min, and an isotacticity of 97%; component m is the above-mentioned mixed toughening agent 1#.

[0123] The components obtained above are weighed and mixed according to the proportions, wherein the mass fraction of component a, Wa, is 80 parts by weight, and the mass fraction of component m, Wm, is 20 parts by weight.

[0124] Add 0.05 parts by weight of β-crystal nucleating agent of grade VP101B. Then, add the mixture to a high-speed mixer and mix evenly. Then, add the mixed material to the feeder of a twin-screw extruder manufactured by W&P. The material enters the twin screw through the feeder. During the processing, the screw temperature is maintained between 200-230°C. After being melted and mixed evenly by the screw, extruded, granulated and dried, polypropylene composition granules are obtained. The melting point of polypropylene composition A is tested to be 156°C.

[0125] (2) Preparation of polypropylene composition B:

[0126] Component x is random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene-butene terpolymer with a melting point of 140℃ and a melt flow rate of 6.6 g / 10 min; component n is the above-mentioned mixed toughening agent 1#.

[0127] The components obtained above are weighed and mixed according to the ratio, wherein the mass part of component x, Wx, is 85 parts by weight and the mass part of component n, Wn, is 15 parts by weight. Other steps are the same as in step (1). Finally, polypropylene composition B granules are obtained, and its melting point is 137℃.

[0128] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0129] 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.

[0130] 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.

[0131] 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 6 times. After stretching, the film is wound up to form a polypropylene sheet (composite film), which consists of an upper surface layer (film layer A), a core layer (film layer A), and a lower surface layer (film layer B).

[0132] 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.

[0133] (4) Preparation of polypropylene fabric:

[0134] 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.

[0135] (5) Preparation of polypropylene composite materials:

[0136] The polypropylene fabrics obtained in step (4) were sequentially stacked and hot-pressed to form a laminated polypropylene sheet. The laminated polypropylene sheet consisted of 24 layers of polypropylene fabric, with the warp and weft directions arranged at 90° angles. The hot-pressing conditions were: 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 composite material was 1.67 mm.

[0137] Example 2

[0138] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0139] (1) Preparation of polypropylene composition A:

[0140] Component a is homopolymer polypropylene 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 m is SEBS (Kraton 1652 from the United States).

[0141] The components obtained above were weighed and mixed according to the specified proportions, wherein component a (Wa) had a mass fraction of 70 parts by weight and component m (Wm) had a mass fraction of 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 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 melting point of polypropylene composition A was determined to be 160°C.

[0142] (2) Preparation of polypropylene composition B:

[0143] Component x is random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry, with a melting point of 134℃, and is an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min; component n is SEBS (Kraton 1652, USA).

[0144] The components obtained above are weighed and mixed according to the ratio, wherein the mass part of component x, Wx, is 80 parts by weight and the mass part of component n, Wn, is 20 parts by weight. Other steps are the same as in step (1). Finally, polypropylene composition B granules are obtained. The melting point of polypropylene composition B is 129℃.

[0145] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0146] The preparation process is the same as step (3) in Example 1.

[0147] (4) Preparation of polypropylene fabric:

[0148] The preparation process is the same as step (4) of Example 1.

[0149] (5) Preparation of polypropylene composite materials:

[0150] The preparation process is the same as step (5) in Example 1.

[0151] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0152] Example 3

[0153] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0154] (1) Preparation of polypropylene composition A:

[0155] Same as Example 1, wherein component m is a propylene-based elastomer (Mobil VISTAMAXX 6102); the mass fraction Wa of component a is 90 parts by weight, and the mass fraction Wm of component m is 10 parts by weight. 0.05 parts by weight of a β-crystal nucleating agent of grade VP101B is added. Polypropylene composition A granules are obtained, and the melting point of polypropylene composition A is determined to be 158°C.

[0156] (2) Preparation of polypropylene composition B:

[0157] Same as in Example 1, wherein component n is a propylene-based elastomer (Mobil VISTAMAXX 6102); the mass fraction Wx of component x is 90 parts by weight, and the mass fraction Wn of component n is 10 parts by weight, and finally polypropylene composition B granules are obtained. The melting point of polypropylene composition B is tested to be 138°C.

[0158] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0159] The preparation process is the same as step (3) in Example 1.

[0160] (4) Preparation of polypropylene fabric:

[0161] The preparation process is the same as step (4) of Example 1.

[0162] (5) Preparation of polypropylene composite materials:

[0163] The preparation process is the same as step (5) in Example 1.

[0164] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0165] Example 4

[0166] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0167] (1) Preparation of polypropylene composition A:

[0168] Same as in Example 1, wherein component m is the above-mentioned mixed toughening agent 2#; polypropylene composition A granules were obtained, and the melting point of polypropylene composition A was tested to be 155°C.

[0169] (2) Preparation of polypropylene composition B:

[0170] Same as in Example 1, wherein component n is the above-mentioned mixed toughening agent 2#; finally, polypropylene composition B granules were obtained, and the melting point of polypropylene composition B was tested to be 136°C.

[0171] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0172] The preparation process is the same as step (3) in Example 1.

[0173] (4) Preparation of polypropylene fabric:

[0174] The preparation process is the same as step (4) of Example 1.

[0175] (5) Preparation of polypropylene composite materials:

[0176] The preparation process is the same as step (5) in Example 1.

[0177] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0178] Example 5

[0179] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0180] (1) Preparation of polypropylene composition A:

[0181] Same as in Example 1, wherein component m is the above-mentioned mixed toughening agent 3#; polypropylene composition A granules were obtained, and the melting point of polypropylene composition A was tested to be 153°C.

[0182] (2) Preparation of polypropylene composition B:

[0183] Same as in Example 1, wherein component n is the above-mentioned mixed toughening agent 3#; finally, polypropylene composition B granules were obtained, and the melting point of polypropylene composition B was tested to be 135°C.

[0184] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0185] The preparation process is the same as step (3) in Example 1.

[0186] (4) Preparation of polypropylene fabric:

[0187] The preparation process is the same as step (4) of Example 1.

[0188] (5) Preparation of polypropylene composite materials:

[0189] The preparation process is the same as step (5) in Example 1.

[0190] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0191] Example 6

[0192] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0193] (1) Preparation of polypropylene composition A:

[0194] Same as in Example 1, wherein component m is the above-mentioned hydrogenated butadiene nitrile rubber, i.e., raw material (11); polypropylene composition A granules are obtained, and the melting point of polypropylene composition A is tested to be 156°C.

[0195] (2) Preparation of polypropylene composition B:

[0196] Same as in Example 1, wherein component n is the above-mentioned hydrogenated butadiene nitrile rubber, i.e., raw material (11); finally, polypropylene composition B granules are obtained, and the melting point of polypropylene composition B is detected to be 138°C.

[0197] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0198] The preparation process is the same as step (3) in Example 1.

[0199] (4) Preparation of polypropylene fabric:

[0200] The preparation process is the same as step (4) of Example 1.

[0201] (5) Preparation of polypropylene composite materials:

[0202] The preparation process is the same as step (5) in Example 1.

[0203] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0204] Example 7

[0205] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0206] (1) Preparation of polypropylene composition A:

[0207] Same as in Example 1, wherein component m is POE-g-MAH; polypropylene composition A granules were obtained, and the melting point of polypropylene composition A was tested to be 152°C.

[0208] (2) Preparation of polypropylene composition B:

[0209] Same as Example 1, wherein component n is POE-g-MAH; finally, polypropylene composition B granules were obtained, and the melting point of polypropylene composition B was tested to be 133℃.

[0210] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0211] The preparation process is the same as step (3) in Example 1.

[0212] (4) Preparation of polypropylene fabric:

[0213] The preparation process is the same as step (4) of Example 1.

[0214] (5) Preparation of polypropylene composite materials:

[0215] The preparation process is the same as step (5) in Example 1.

[0216] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0217] Example 8

[0218] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0219] (1) Preparation of polypropylene composition A:

[0220] The preparation process is the same as step (1) in Example 1.

[0221] (2) Polypropylene composition B i Preparation:

[0222] The main preparation process is the same as step (2) in Example 1. The difference is that component B... i Chinese x i The materials selected are as follows:

[0223] Component x1 is random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry. It is an ethylene-propylene-butene terpolymer with a molecular weight distribution Mw / Mn of 8.9, a melt flow rate of 8.1 g / 10 min, and a melting point of 130℃.

[0224] Component x2 is random copolymer polypropylene produced by Sinopec Beijing Research Institute of Chemical Industry. It is an ethylene-propylene-butene terpolymer with a molecular weight distribution Mw / Mn of 7.6, a melt flow rate of 7.2 g / 10 min, and a melting point of 135℃.

[0225] Component x3 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 molecular weight distribution Mw / Mn of 7.3, a melt flow rate of 6.6 g / 10 min, and a melting point of 140℃.

[0226] Component n remains the same as the above-mentioned mixed toughening agent 1#;

[0227] Finally, polypropylene composition B was obtained. i Granular material (i.e., x) i +n=B i (i = 1, 2, 3), after testing, the melting point of B1 is 128℃, the melting point of B2 is 133℃, and the melting point of B3 is 138℃.

[0228] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0229] The preparation process is the same as step (3) of Example 1. Sheets B1AB1, B2AB2, and B3AB3 were prepared respectively.

[0230] (4) Preparation of polypropylene fabric:

[0231] The preparation process is the same as step (4) in Example 1. Plain weave polypropylene fabrics B1AB1, B2AB2, and B3AB3 were obtained.

[0232] (5) Preparation of polypropylene composite materials:

[0233] The polypropylene fabrics obtained in step (4) were stacked sequentially from bottom to top as follows: B3A3B3, B2A2B2, B1A1B1, B2A2B2, and B3A3B3, for a total of 5 layers. The stacked polypropylene fabrics were then hot-pressed together and cooled to form a polypropylene composite material. The polypropylene fabrics were placed at a 90° angle between the warp and weft directions. The hot-pressing conditions were: temperature 145℃, hot-pressing pressure 5MPa, preheating time 90s, hot-pressing time 90s, and cooling time 300s. The thickness of the prepared polypropylene composite material was 412μm.

[0234] Example 9

[0235] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0236] (1) Preparation of polypropylene composition A:

[0237] The preparation process is the same as step (1) in Example 1.

[0238] (2) Polypropylene composition B i Preparation:

[0239] The main preparation process is the same as step (2) in Example 1. The difference is that component B... i Chinese x i The materials selected are as follows:

[0240] Components x1-x4 are 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 128℃; components x5-x8 are 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℃; components x9-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 142℃; 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.

[0241] Component n remains the same as the above-mentioned mixed toughening agent 1#;

[0242] Finally, polypropylene composition B was obtained. i Granular material (i.e., x) i +n=B i (i = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), after testing, the melting point of B1-B4 is 127℃, the melting point of B5-B8 is 135℃, and the melting point of B9-B... 12 Its melting point is 141℃.

[0243] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0244] The preparation process is the same as step (3) in Example 1.

[0245] (4) Preparation of polypropylene fabric:

[0246] The preparation process is the same as step (4) of Example 1.

[0247] (5) Preparation of polypropylene composite materials:

[0248] The polypropylene fabrics obtained in step (4) above are stacked sequentially, from bottom to top as B. 12 AB 12 …B3AB3, B2AB2, B1AB1, B1AB1, B2AB2, B3AB3, …B 12 AB 12 The total number of layers is 24. The laminated polypropylene fabrics are hot-pressed and fused together, then cooled and shaped to form a polypropylene composite material. The polypropylene fabrics are placed at a 90° angle between the warp and weft directions. The hot-pressing conditions are: temperature 150℃, hot-pressing pressure 5MPa, preheating time 160s, hot-pressing time 160s, and cooling time 600s. The prepared polypropylene composite material has a thickness of 1.66mm.

[0249] Comparative Example 1

[0250] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0251] (1) Preparation of polypropylene composition A:

[0252] Same as Example 1, but without adding component m;

[0253] (2) Preparation of polypropylene composition B:

[0254] Same as Example 1, but without adding component n;

[0255] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0256] The preparation process is the same as step (3) in Example 1.

[0257] (4) Preparation of polypropylene fabric:

[0258] The preparation process is the same as step (4) of Example 1.

[0259] (5) Preparation of polypropylene composite materials:

[0260] The preparation process is the same as step (5) in Example 1.

[0261] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0262] Comparative Example 2

[0263] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0264] (1) Preparation of polypropylene composition A:

[0265] Same as Example 1.

[0266] (2) Preparation of polypropylene composition B:

[0267] Same as Example 1, but without adding component n;

[0268] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0269] The preparation process is the same as step (3) in Example 1.

[0270] (4) Preparation of polypropylene fabric:

[0271] The preparation process is the same as step (4) of Example 1.

[0272] (5) Preparation of polypropylene composite materials:

[0273] The preparation process is the same as step (5) in Example 1.

[0274] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0275] Comparative Example 3

[0276] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0277] (1) Preparation of polypropylene composition A:

[0278] Same as Example 1, but without adding component n;

[0279] (2) Preparation of polypropylene composition B:

[0280] Same as Example 1.

[0281] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0282] The preparation process is the same as step (3) in Example 1.

[0283] (4) Preparation of polypropylene fabric:

[0284] The preparation process is the same as step (4) of Example 1.

[0285] (5) Preparation of polypropylene composite materials:

[0286] The preparation process is the same as step (5) in Example 1.

[0287] The thickness of the prepared polypropylene composite material is similar to that of Example 1.

[0288] Comparative Example 4

[0289] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0290] (1) Preparation of polypropylene composition A:

[0291] Same as Example 1. However, m is a polypropylene impact copolymer produced by the Beijing Research Institute of Chemical Industry of Sinopec (impact strength 23 KJ / m under 23℃ testing conditions). 2 The composition has an ethylene content of 11% wt, a melt flow rate of 2.0 g / 10 min, and a melting point of 155 °C. The melting point of its polypropylene composition A was determined to be 157 °C.

[0292] (2) Preparation of polypropylene composition B:

[0293] Same as Example 1;

[0294] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0295] The preparation process is the same as step (3) in Example 1.

[0296] (4) Preparation of polypropylene fabric:

[0297] The preparation process is the same as step (4) of Example 1.

[0298] (5) Preparation of polypropylene composite materials:

[0299] The preparation process is the same as step (5) in Example 1.

[0300] Comparative Example 5

[0301] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0302] (1) Preparation of polypropylene composition A:

[0303] Same as Example 1.

[0304] (2) Preparation of polypropylene composition B:

[0305] Same as Example 1, but component n is petroleum resin (C5 Lanzhou Petrochemical), and the final product is polypropylene composition B granules, which are tested to have a melting point of 135°C;

[0306] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0307] The preparation process is the same as step (3) in Example 1.

[0308] (4) Preparation of polypropylene fabric:

[0309] The preparation process is the same as step (4) of Example 1.

[0310] (5) Preparation of polypropylene composite materials:

[0311] The preparation process is the same as step (5) in Example 1.

[0312] Comparative Example 6

[0313] This embodiment illustrates the preparation of the polypropylene composition, three-layer co-extruded polypropylene sheet, polypropylene fabric, and polypropylene composite material provided by the present invention.

[0314] (1) Preparation of polypropylene composition A:

[0315] Same as Example 1. However, m is a polypropylene impact copolymer produced by the Beijing Research Institute of Chemical Industry of Sinopec (impact strength 23 KJ / m under 23℃ testing conditions). 2 The composition has an ethylene content of 11% wt, a melt flow rate of 2.0 g / 10 min, and a melting point of 155 °C. The melting point of polypropylene composition A was determined to be 157 °C.

[0316] (2) Preparation of polypropylene composition B:

[0317] Same as Example 1, but component n is petroleum resin (C5 Lanzhou Petrochemical), and the final product is polypropylene composition B granules, which are tested to have a melting point of 135°C;

[0318] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0319] The preparation process is the same as step (3) in Example 1.

[0320] (4) Preparation of polypropylene fabric:

[0321] The preparation process is the same as step (4) of Example 1.

[0322] (5) Preparation of polypropylene composite materials:

[0323] The preparation process is the same as step (5) in Example 1.

[0324] Comparative Example 7

[0325] Three-layer co-extruded polypropylene sheets and polypropylene fabrics were prepared according to the method in Example 8.

[0326] The difference lies in the preparation of the polypropylene composite material. Polypropylene fabrics are layered sequentially from bottom to top as follows: B1A1B1, B2A2B2, B3A3B3, B2A2B2, and B1A1B1, for a total of 5 layers. These layered polypropylene fabrics are then hot-pressed together and cooled to set the composite material. The polypropylene fabrics are placed at a 90° angle between the warp and weft directions. The hot-pressing conditions are: temperature 145℃, hot-pressing pressure 5MPa, preheating time 110s, hot-pressing time 110s, and cooling time 300s. The resulting polypropylene composite material has a thickness of 416μm.

[0327] Comparative Example 8

[0328] Three-layer co-extruded polypropylene sheets and polypropylene fabrics were prepared according to the method of Example 9.

[0329] The difference lies in the preparation of the polypropylene composite material, where the obtained polypropylene fabric is layered sequentially, from bottom to top as B1AB. 1… B 10 AB 10 B 11 AB 11 B 12 AB 12 B 12 AB 12 B 11 AB 11 B 10 AB 10 The total number of layers in the B1AB1 laminate is 24. The laminated polypropylene fabrics are hot-pressed together and then cooled and shaped to form a polypropylene composite material. The polypropylene fabrics are placed at a 90° angle between the warp and weft directions. The hot-pressing conditions are: temperature 150℃, hot-pressing pressure 5MPa, preheating time 160s, hot-pressing time 160s, and cooling time 600s. The prepared polypropylene composite material has a thickness of 1.60mm.

[0330] Experimental Example

[0331] The polypropylene 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.

[0332] (1) Tensile strength: Samples were prepared and tested in accordance with the methods specified in GB / T1040.1-2018.

[0333] (2) Interlayer peel strength: Samples were prepared and measured in accordance with the method specified in QB / T2358-98.

[0334] (3) Low temperature (-20℃) drop hammer impact strength: The test was conducted according to the method specified in GB / T14153-1993. Among them, the thickness of the polypropylene composite materials obtained in Examples 1-5 and Comparative Examples 1-5 were all similar, around 1.6 mm, and all within the range of 1.6 mm ± 1 mm.

[0335] Table 1

[0336]

[0337]

[0338] The examples and test results in Table 1 show that the polypropylene composite material prepared according to the present invention has excellent tensile properties, low-temperature impact properties, and good interlaminar peel strength at relatively low hot-pressing temperatures. When the polypropylene composite material of the present invention is made of 24 layers of polypropylene fabric hot-pressed together with a thickness of approximately 1.6 mm, its low-temperature drop hammer impact strength at -20°C is ≥160 J.

[0339] As can be seen from Comparative Examples 1-8, compared with Example 1 of this case, a series of comparative examples that do not use toughening components m / n or use conventional impact-resistant copolymer polypropylene as component m and conventional binder C5 petroleum resin as component n show that the low-temperature impact performance and interlaminar peel strength of the obtained polypropylene composite material cannot be simultaneously achieved, and both are reduced, with the low-temperature impact performance showing a significant decrease.

[0340] 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.

[0341] 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. An impact-resistant polypropylene sheet, comprising layer A and layers B and B' located on both sides of layer A, having a structure of BAB'; Layer A contains polypropylene composition A, which includes homopolymer polypropylene a and toughening agent m; layer B may be the same as or different from layer B', and each contains polypropylene composition B and polypropylene composition B', which each includes random copolymer polypropylene x and toughening agent n. in, The melting point of the polypropylene composition A is greater than that of the polypropylene composition B and the polypropylene composition B'. The toughening agent m and the toughening agent n may be the same or different, and each is selected from elastic materials.

2. The impact-resistant polypropylene sheet according to claim 1, characterized in that: The melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in polypropylene composition B and polypropylene composition B'; and / or, The difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B, and the difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B', are each greater than or equal to 5°C; and / or, based on the total thickness of the impact-resistant polypropylene sheet, the thickness of layer A accounts for 51%-89% of the total thickness.

3. The impact-resistant polypropylene sheet according to claim 1, characterized in that: The melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in polypropylene composition B and polypropylene composition B', and the temperature difference between the corresponding melting points is greater than or equal to 10°C; and / or, The difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B, and the difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B', are each greater than or equal to 10°C; and / or, based on the total thickness of the impact-resistant polypropylene sheet, the thickness of layer A accounts for 71%-89% of the total thickness.

4. The impact-resistant polypropylene sheet according to claim 1, characterized in that: Based on the total thickness of the impact-resistant polypropylene sheet, the thickness of layer A accounts for 71%-80% of the total thickness.

5. The impact-resistant polypropylene sheet according to claim 1, characterized in that: Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 50-98 wt% homopolymer polypropylene a, 2-50 wt% toughening agent m; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 70-98 wt% random copolymer polypropylene x and 2-50 wt% toughening agent n.

6. The impact-resistant polypropylene sheet 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% toughening agent m; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 70-90 wt% random copolymer polypropylene x and 10-30 wt% toughening agent n.

7. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The homopolymer polypropylene a has: Melting point is 150-170℃; and / or, The melt flow rate at 230℃ and 2.16kg load is 0.5-50g / 10min; and / or, The isomechanics is not less than 96%.

8. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The homopolymer polypropylene a has: Melting point is 160-170℃; and / or, The melt flow rate at 230℃ and 2.16kg load is 1-20g / 10min.

9. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The homopolymer polypropylene a has: The melt flow rate at 230℃ and 2.16kg load is 2.5-18g / 10min.

10. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The toughening agent m and the toughening agent n are each selected from elastomers and / or soft biodegradable materials.

11. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or modifiers of at least one of the following substances: polyolefin elastomers, EPDM rubber, SEBS, SBS, EVA, biodegradable polyester, natural rubber, bio-based elastomer specialty rubbers.

12. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or modifiers of at least one of the following substances: polybutylene terephthalate, polybutylene terephthalate, polybutylene succinate and its copolymers, polycaprolactone, natural rubber, hydrogenated nitrile rubber, and polyolefin elastomers.

13. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The toughening agent m and the toughening agent n are each selected from at least one of the following substances and / or at least one of the following modified substances: polyolefin elastomer, hydrogenated nitrile rubber.

14. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The toughening agent m and the toughening agent n are each selected from polyolefin elastomer maleic anhydride modified and hydrogenated nitrile rubber.

15. The impact-resistant polypropylene sheet according to claim 14, characterized in that: The weight ratio of the modified maleic anhydride polyolefin elastomer to the hydrogenated nitrile rubber is 0.2 to 5.

16. The impact-resistant polypropylene sheet according to claim 13, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene with the following olefins: propylene and / or α-olefins.

17. The impact-resistant polypropylene sheet according to claim 16, characterized in that: The α-olefin is a C4-C12 α-olefin.

18. The impact-resistant polypropylene sheet according to claim 16, characterized in that: The α-olefin is 1-butene and / or 1-octene.

19. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The random copolymer polypropylene x has: Melting point is 110-150℃; and / or, The melt flow rate at 230℃ and 2.16kg load is 0.5-50g / 10min; and / or, The molecular weight distribution Mw / Mn is 5-12; and / or, The random copolymer polypropylene x is a copolymer of propylene with ethylene and / or butene.

20. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The random copolymer polypropylene x has: Melting point is 120-140℃; and / or, The melt flow rate at 230℃ and 2.16kg load is 1-20g / 10min; and / or, The molecular weight distribution Mw / Mn is 7-10; and / or, The random copolymer polypropylene x is an ethylene-propylene-butene terpolymer and / or a propylene-ethylene binary copolymer.

21. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The random copolymer polypropylene x has: The melt flow rate at 230℃ and 2.16kg load is 3-18g / 10min.

22. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: Layer A also contains a β-crystal nucleating agent.

23. The impact-resistant polypropylene sheet according to claim 22, 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, The content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight relative to 100 parts by weight of polypropylene composition A.

24. The impact-resistant polypropylene sheet according to any one of claims 1-6, characterized in that: The BAB' layer structure of the impact-resistant polypropylene sheet is obtained by co-extruding a layer A raw material containing a polypropylene composition A, a layer B raw material containing a polypropylene composition B, and a layer B' raw material containing a polypropylene composition B'.

25. A method for preparing the impact-resistant polypropylene sheet according to any one of claims 1-24, comprising co-extruding, casting or calendering, and stretching a layer A raw material containing a polypropylene composition A, a layer B raw material containing a polypropylene composition B, and a layer B' raw material containing a polypropylene composition B' according to a BAB' structure to obtain the impact-resistant polypropylene sheet.

26. The method for preparing the impact-resistant polypropylene sheet according to claim 25, characterized in that, The preparation of the raw material for layer A includes melt blending of components including the homopolymer polypropylene a and the toughening agent m; and / or, The preparation of the raw materials for layers B and B' includes the melt blending of each component, including the random copolymer polypropylene x and the toughening agent n; and / or, The temperatures for co-extrusion and casting are each independently selected from 200-240°C; and / or, The rolling temperature is 50-70℃; and / or, The stretching conditions include: a stretching temperature of 90-165℃; and a stretching ratio of 1-20 times.

27. The method for preparing the impact-resistant polypropylene sheet according to claim 25, characterized in that, The stretching conditions include: a stretching temperature of 90-140℃ and a stretching ratio of 1-20 times.

28. The method for preparing the impact-resistant polypropylene sheet according to claim 25, characterized in that, The stretching conditions include: a stretching temperature of 90-119℃ and a stretching ratio of 1-20 times.

29. An impact-resistant polypropylene fabric, a three-dimensional polypropylene fabric obtained by weaving the impact-resistant polypropylene sheet according to any one of claims 1-24.

30. The impact-resistant polypropylene fabric according to claim 29, characterized in that, The impact-resistant polypropylene fabric is obtained by slitting and weaving the impact-resistant polypropylene sheet; and / or, the impact-resistant polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

31. An impact-resistant polypropylene composite material, wherein the impact-resistant polypropylene composite material is prepared by hot pressing together multiple layers of impact-resistant polypropylene sheets according to any one of claims 1-24 and / or impact-resistant polypropylene fabrics according to claims 29 or 30.

32. An impact-resistant polypropylene composite material according to claim 31, characterized in that, The impact-resistant polypropylene composite material is prepared by hot pressing multiple layers of the impact-resistant polypropylene sheets or the impact-resistant polypropylene fabric; and / or Multi-layer impact-resistant polypropylene sheets are stacked from top to bottom at 0-90° angles along their respective machine directions; and / or, Multi-layer impact-resistant polypropylene fabric is stacked from top to bottom with warp directions arranged at 0-90° intervals; and / or, The number of layers in the multi-layer impact-resistant polypropylene sheet and / or multi-layer impact-resistant polypropylene fabric is greater than or equal to 2.

33. An impact-resistant polypropylene composite material according to claim 31, characterized in that, The number of layers in multi-layer impact-resistant polypropylene sheets and / or multi-layer impact-resistant polypropylene fabrics ranges from 2 to 200.

34. An impact-resistant polypropylene composite material according to claim 31, characterized in that, The number of layers in multi-layer impact-resistant polypropylene sheets and / or multi-layer impact-resistant polypropylene fabrics ranges from 4 to 100.

35. The impact-resistant polypropylene composite material according to any one of claims 31-34, characterized in that: The impact-resistant polypropylene composite material 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 impact-resistant 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 the average melting point of the outermost layer in the (i-1)-th group.

36. The impact-resistant polypropylene composite material according to claim 35, 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.

37. The impact-resistant polypropylene composite material according to claim 35, 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 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.

38. The impact-resistant polypropylene composite material according to claim 35, 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℃.

39. A method for preparing an impact-resistant polypropylene composite material according to any one of claims 31-38, the method comprising hot-pressing and fusing the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric together, and then cooling and shaping it to form an impact-resistant polypropylene composite material.

40. The method for preparing the impact-resistant polypropylene composite material according to claim 39, characterized in that, The hot-pressing fusion temperature is 115-170℃; and / or, The pressure for 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 s; And / or, the number of layers in the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric laminate is greater than or equal to 2 layers; and / or, The adjacent layers of the impact-resistant polypropylene fabric laminate are placed at an angle of 0-90° between the warp directions; and / or, The adjacent layers of the impact-resistant polypropylene sheet stack are placed at 0-90° along their respective machine directions.

41. The method for preparing the impact-resistant polypropylene composite material according to claim 39, characterized in that, The hot-pressing fusion temperature is 115-159℃; and / or, The preheating time for the hot-pressing fusion is 5-600s, and the hot-pressing time is 10-500s; and / or, And / or, the number of layers of the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric stack is 2-200 layers.

42. The method for preparing the impact-resistant polypropylene composite material according to claim 39, characterized in that, The number of layers in the impact-resistant polypropylene sheet and / or the impact-resistant polypropylene fabric stack is 4-100.

43. The applications of the impact-resistant polypropylene sheet according to any one of claims 1-24, the impact-resistant polypropylene fabric according to claim 29 or 30, the impact-resistant polypropylene composite material according to any one of claims 31-38, and the impact-resistant polypropylene composite material prepared by the preparation method according to any one of claims 39-42 in the fields of electrical component packaging, automobile manufacturing, military materials, and consumer products.

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