Polypropylene composite material with melting point gradient structure, its production method, system and its use

Abstract

FIELD: polymer composite materials.SUBSTANCE: polypropylene composite material having a structure with a melting temperature gradient, a method for producing it, a system and its application. The polypropylene composite material comprises sequentially stacked groups of polypropylene layers; each group of polypropylene layers comprises at least one of the same or different polypropylene layers with the structure BiAiB'i; the structure of the polypropylene composite material looks like group n, ..., group i, ..., group 2, group 1, group 2, ..., group i, ..., group n; the melting point of the polypropylene composition Ai is higher than the melting point of the polypropylene compositions Bi and B'i; and the average value of the melting temperatures of all outer layers in group i is greater than the average value of the melting temperatures of all outer layers in group (i-1).EFFECT: material having a melting temperature gradient structure according to the present invention has both excellent mechanical properties and good tear strength of the intermediate layer at a relatively low hot pressing temperature.58 cl, 1 dwg, 3 tbl

Description

[0001] FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0002] The present invention relates to a polypropylene composite material, as well as a polypropylene composite material having a melting temperature gradient structure, a method for producing the same, a system and its use.

[0003] STATE OF THE ART

[0004] In recent years, high-strength and impact-resistant polymer composite materials with easy processability and light weight, especially self-reinforced polymer composite materials, have become one of the research hot spots.

[0005] The reinforcing phase and matrix of self-reinforced polymer composite materials consist of polymers of the same type but different morphologies. The reinforcing phase is typically highly oriented fibers or flat ribbons. Most self-reinforced polymer composite materials are produced by hot pressing. When the reinforcing phase is hot pressed at a certain pressure and temperature, the surface of the reinforcing phase fibers melts into the matrix melt. The matrix melt and the surface of the reinforcing phase co-crystallize during melting, thus ensuring sufficient adhesion strength at the interface between them. For example, in patent document US8021592B2, melt-spun oriented polyolefin fibers with a weight-average molecular weight of less than 250,000 are woven and then hot-pressed. The surface layer of the polyolefin fabric is partially melted and bonded by using specific high temperature, pressure, and cooling time to produce a polyolefin sheet. This production method is sensitive to hot-pressing temperature, and the required hot-pressing temperature is high. The oriented fibers in the resulting polyolefin fiber composites generate relatively large misorientations after hot-pressing, significantly reducing the mechanical strength, and further improving the self-reinforcement effect.

[0007] In order to expand the hot pressing window and reduce the hot pressing pressure, patent document US8133537B2 proposes hot pressing three layers of polyolefin fibers with different melting temperatures to produce a polyolefin composite material, in which the melting temperature of the first and second polyolefin layers is lower than that of the middle layer, and it is noted that the viscosity of the second polymer does not exceed approximately 10% of the viscosity of the first polymer at 170°C. However, the impact strength and tear strength of the intermediate layer of the hot-pressed composite material produced by this method are low, and it is impossible to obtain a hot-pressed composite material that simultaneously has good mechanical properties and higher tear strength of the intermediate layer.

[0008] SUMMARY OF THE INVENTION

[0009] The objective of the present invention is to overcome the technical problems that make it difficult for existing polypropylene composite materials to simultaneously achieve a wider processing temperature range, higher mechanical properties, and higher tear strength of the intermediate layer. The present invention provides a polypropylene composite material with a melting temperature gradient structure, a method for producing the same, and a system and its use by integrating a structure with a melting temperature gradient in stacked polypropylene. This method can reduce the duration of hot pressing while improving production efficiency and reducing energy consumption during production. The polypropylene composite material obtained by this method simultaneously exhibits excellent mechanical properties and good tear strength of the intermediate layer.

[0010] The first object of the present invention is to provide a polypropylene composite material comprising a plurality of groups of sequentially laid polypropylene layers; each group of polypropylene layers comprises at least one of the same or different polypropylene layers, and each polypropylene layer comprises a base layer A i and outer layers B i and B' i , located on both sides of the main layer A i , with structure B i A i B' i ; the structure of the polypropylene composite material looks like group n,... group i,... group 2, group 1, group 2,... group i,... group n, in the direction from bottom to top, the total number of stacked groups of polypropylene layers is 2n-1; i and n are integers not less than 2, and i≤n; the main layer A i in the polypropylene layer contains a polypropylene composition A i , outer layer B iis the same as or different from the outer layer B' i , outer layer B i contains polypropylene composition B i , and the outer layer B' i contains polypropylene composition B' i , melting temperature of polypropylene composition A i greater than the melting point of polypropylene composition B i and polypropylene composition B' i ; and the average value of melting temperatures of all outer layers in group i is greater than the average value of melting temperatures of all outer layers in group i-1.

[0011] According to the present invention, in the structure of the polypropylene composite material, the group i located on the top may be the same as or different from the group i located on the bottom.

[0012] In a preferred embodiment of the present invention, each of the difference between the melting point of the polypropylene composition A iand the melting temperature of the polypropylene composition B i and the difference between the melting temperature of the polypropylene composition A i and the melting temperature of the polypropylene composition B' i greater than or equal to 5°C, preferably greater than or equal to 10°C, more preferably greater than or equal to 20°C; and most preferably 20-60°C.

[0013] According to the present invention, the base layer in each polypropylene layer may be composed of the same material or different materials, and the present invention is not particularly limited thereto. If the melting point of A i is higher than the melting point of polypropylene composition B i and polypropylene composition B' i , better technical effects can be achieved.

[0014] In a preferred embodiment of the present invention, the differences 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 same or different, are each 1-40°C, preferably 1-10°C, and more preferably 1-5°C.

[0015] According to the present invention, the total number of stacked groups of polypropylene layers is 2n-1, and the present invention has a wide range of selection for the total number of stacked groups of polypropylene layers. In a preferred embodiment of the present invention, it is preferably 2≤≤n≤100, more preferably 2≤n≤50, and even more preferably 2≤n≤30.

[0016] According to the present invention, the number of polypropylene layers contained in each group of polypropylene layers can be selected within a wide range. In a preferred embodiment of the present invention, each group of polypropylene layers independently comprises 1-10, preferably 1-5, more preferably 1-3 identical or different polypropylene layers, more preferably 1 polypropylene layer. It is preferable that the number of polypropylene layers contained in each group of polypropylene layers is the same.

[0017] It is preferable, but not required, that the melting point of any outer layer in each group is within ±10°C, ±5°C, preferably ±3°C, more preferably ±1°C relative to the average value of the melting points of all outer layers in the group.

[0018] In the embodiment where each group of polypropylene layers comprises only 1 polypropylene layer, for example, the structure of the polypropylene composite material may be 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 , in the direction from bottom to top, the total number of laid polypropylene layers is 2n-1; i and n are integers not less than 2, and i≤n.

[0019] In the embodiment where each group of polypropylene layers comprises 2 or more polypropylene layers, for example, the structure of group i of polypropylene layers 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 (B n1 An1 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), in the direction from bottom to top, the total number of laid polypropylene layers is j+2k+……2p+……2q; j, k, p, q are independently integers of at least 2, preferably 2-10, more preferably 2-5, and more preferably 2-3.

[0020] In a preferred embodiment of the present invention, the polypropylene layer also comprises intermediate layers C i and C' i , and the structure of the polypropylene layer is B i C i A i C' i B' i ; intermediate layer C i is the same or different from the intermediate layer C' i , intermediate layer C i contains polypropylene composition C i , and the intermediate layer C' i contains polypropylene composition C' i ; and the melting temperature of the polypropylene composition A i greater than the melting point of the polypropylene composition C i and polypropylene composition C'i .

[0021] According to the present invention, the percentage of the thickness of the base layer A i in each polypropylene layer can be selected within wide limits. In a preferred embodiment of the present invention, the thickness of the base layer A i in each polypropylene layer is 51-89% of the total thickness of the polypropylene layer, preferably 71-89%, and more preferably 71-80%. The thicknesses of the outer layers B i and B' i , located on both sides of the main layer A i , may be the same or different, and are preferably the same. The thicknesses of the intermediate layers C i and C' i , located on both sides of the main layer A i , may be the same or different, and are preferably the same.

[0022] The thickness of each polypropylene layer can be selected within a wide range. In a preferred embodiment of the present invention, the thickness of each polypropylene layer is 10-1000 μm, preferably 30-500 μm, and more preferably 50-300 μm.

[0023] According to the present invention, the thickness of the base layer A i , outer layers B i , B' i and intermediate layers C i , C' i can be controlled by the extruder melt pump during processing.

[0024] According to the present invention, a polypropylene composition A i comprises, but is not limited to, one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; each of the polypropylene compositions B i and B' icontains, but is not limited to, one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer, and an optional reinforcement y i thermal bonding; each of the polypropylene compositions C i and C' i contains, but is not limited to, one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer, and an optional reinforcement z i thermal bonding.

[0025] According to the present invention, a polypropylene composition A i can be selected within wide limits. In a preferred embodiment of the present invention, the polypropylene composition A i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer.

[0026] According to the present invention, each of the polypropylene compositions Bi and B' i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; preferably a polypropylene composition B i and / or polypropylene composition B' i also contains the y amplifier i thermal bonding.

[0027] According to the present invention, each of the polypropylene compositions C i and C' i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; preferably a polypropylene composition C i and / or polypropylene composition C' i also contains the z amplifier i thermal bonding.

[0028] In a more preferred embodiment of the present invention, the polypropylene composition Ai comprises a polypropylene homopolymer a i and polypropylene block copolymer b i; in an even more preferred embodiment of the present invention, the polypropylene composition A i contains 50-99 wt.% of polypropylene homopolymer a i and 1-50 wt. % polypropylene block copolymer b i ; more preferably a polypropylene composition A i contains 70-90 wt.% of polypropylene homopolymer a i and 10-30 wt. % polypropylene block copolymer b i by total weight of polypropylene composition A i .

[0029] In a more preferred embodiment of the present invention, each of the polypropylene compositions B i and B' i contains a random copolymer of polypropylene x i and amplifier y i thermal bonding; preferably each of the polypropylene compositions B i and B' i contains 70-99 wt.% random copolymer of polypropylene x i and 1-30 wt.% of the enhancer y ithermal bonding, preferably polypropylene composition B i contains 80-90 wt.% random copolymer of polypropylene x i and 10-20 wt.% of the enhancer y i thermal bonding by total weight of each polypropylene composition B i or B' i .

[0030] In a more preferred embodiment of the present invention, each of the polypropylene compositions C i and C' i contains a random copolymer of polypropylene β i , polypropylene homopolymer γ i and amplifier z i thermal bonding; preferably each of the polypropylene compositions C i and C' i contains 30-60 wt.% of the enhancer z i thermal bonding, 35-55 wt.% random copolymer of polypropylene β i and 5-15 wt.% of polypropylene homopolymer γ i ; more preferably 35-55 wt.% of the enhancer z ithermal bonding, 40-55 wt.% random copolymer of polypropylene β i and 5-10 wt.% of polypropylene homopolymer γ i by the total weight of each polypropylene composition C i or C' i .

[0031] According to the present invention, a polypropylene composition a i can be selected within wide limits. In a preferred embodiment of the present invention, the polypropylene homopolymer a i has a melting point of 150-170°C, preferably 160-170°C; and / or a stereoregularity (mm) of at least 96%, preferably at least 97%, and more preferably at least 98%.

[0032] According to the present invention, the melt flow rate of the polypropylene homopolymer a i can be selected within a wide range, preferably a polypropylene homopolymer a ihas a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min.

[0033] According to the present invention, “and / or” refers to any one condition or a combination of two conditions.

[0034] According to the present invention, a polypropylene block copolymer b i can be selected within wide limits. In a preferred embodiment of the present invention, the polypropylene block copolymer b i has a melting point of 150-170°C, the monomer copolymerizable with propylene in the polypropylene block copolymer is ethylene or butene, preferably butene; and / or the polypropylene block copolymer has an Izod impact strength of at least 20 kJ / m 2 (at 23°C).

[0035] According to the present invention, the melt flow rate of the polypropylene block copolymer b ican be selected within a wide range, preferably a block copolymer of polypropylene b i has a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min.

[0036] As a result of the study conducted by the inventors of the present invention, it was found that when the melt mass flow rate and the composition ratio of the polymers in the raw material used in the polypropylene composition A i , are within the preferred range, block copolymer of polypropylene b i in the composition can better absorb the impact energy, meeting the impact performance requirements, so that the sheet has good impact performance. At the same time, since the macromolecular segments in the polypropylene homopolymer a i are relatively regular, crystallization occurs during sheet preparation, so that the sheet also has good stretching properties.

[0037] In a preferred embodiment of the present invention, the polypropylene composition A i also contains a β-nucleating agent; preferably, the β-nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, two-component complexes of Group IIA, aromatic diamides, rare earth metal compounds, and cyclic dicarboxylate nucleating agents.

[0038] According to the present invention, the amount of β-nucleating agent can be selected within a wide range, and the content of β-nucleating agent in the polypropylene composition A is preferable i is 0.01-0.5 m. parts per 100 m. parts of the total amount of polypropylene composition A i In particular, for example, the content of β-nucleating agent can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 m.h.

[0039] In a preferred embodiment of the present invention, the melting point of the random copolymer of polypropylene x i is 110-150°C, preferably 120-140°C, preferably the average melting point of all the random polypropylene copolymers in group i is greater than the average melting point of all the random polypropylene copolymers in group i-1, preferably the melting point difference between them is 1-40°C, more preferably 1-10°C, and most preferably 1-5°C; preferably the random polypropylene copolymer x i is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer.

[0040] According to the present invention, the melt flow rate of the random copolymer of polypropylene x ican be selected within a wide range, and preferably the melt flow rate at 230°C and a load of 2.16 kg is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and more preferably 3-18 g / 10 min. Polypropylene random copolymer x i has a molecular weight distribution Mw / Mn of 5-12, preferably 7-10.

[0041] In a preferred embodiment of the present invention, the amplifier y i thermal bonding has a melting point or laminar flow temperature of 70-110°C. And / or an enhancer y i thermal bonding is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; and preferably a reinforcement y i thermal bonding is a polyolefin elastomer and / or coumarone-indene resin.

[0042] In a preferred embodiment of the present invention, the polyolefin elastomer is preferably an elastomer of ethylene copolymerized with propylene and / or an α-olefin, the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or the coumarone-indene resin is a hydrogenated C5 and / or C9 coumarone-indene resin with a softening point of 100-150°C; preferably a cyclopentadiene type resin.

[0043] According to the present invention, the melt flow rate of the enhancer y i thermal bonding can be selected within wide limits, and the amplifier y is preferred i thermal bonding has a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, preferably 1-18 g / 10 min, and more preferably 3-18 g / 10 min.

[0044] As a result of the study conducted by the inventors of the present invention, it was found that when the corresponding compositional ratios of the polymers in the polypropylene composition B i and polypropylene composition B' i are within the above preferred ranges, a low melting point polypropylene random copolymer x i and amplifier y i Thermal bonding agents in the composition can significantly reduce the hot pressing temperature and expand the hot pressing temperature window. In addition, the y-reinforcer i Thermal bonding provides good adhesive properties for the sheet, further improving the tear strength of the intermediate layer.

[0045] As a result of the study conducted by the inventors of the present invention, it was found that when the corresponding compositional ratios of the polymers in the polypropylene composition A i , polypropylene composition B iand polypropylene composition B' i , as well as the distribution of the thickness of the polymer composition A i are within the above-mentioned preferred ranges, a smoother sheet preparation process can be further ensured, which in turn allows the sheet to have further improved uniformity, tensile strength, impact strength and tear strength of the intermediate layer.

[0046] According to the present invention, when the polypropylene sheet layer has a B structure i C i A i C' i B' i , the percentage of thickness of each layer can be selected within wide limits. In a preferred embodiment of the present invention, the thickness of the base layer A i is 51-89% of the total thickness of the polypropylene sheet layer, preferably 71-89%; the thickness of the intermediate layers C i , C' i is 6-20% of the total thickness, preferably 6-15%; and the thickness of the outer layers Bi , B' i is 5-30% of the total thickness, preferably 5-15%.

[0047] According to the present invention, a random copolymer of polypropylene β i can be selected within wide limits. In a preferred embodiment of the present invention, the random copolymer of polypropylene β i has a melting point of 110-150°C, preferably 120-140°C; and / or a random copolymer of polypropylene β i has a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, more preferably 3-18 g / 10 min; and / or a random copolymer of polypropylene β i has a molecular weight distribution Mw / Mn of 5-12, preferably 7-10. Preferably a random copolymer of polypropylene β i is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer.

[0048] According to the present invention, a polypropylene composition γ i can be selected within wide limits. In a preferred embodiment of the present invention, the polypropylene homopolymer γ i has a melting point of 150-170°C, preferably 160-170°C; and / or a polypropylene homopolymer γ i has a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, more preferably 2.5-18 g / 10 min; and / or a polypropylene homopolymer γ i has a stereoregularity (mm) of at least 96%.

[0049] In a preferred embodiment of the present invention, the amplifier z i thermal bonding has a melting point or laminar flow temperature of 70-110°C. And / or enhancer z ithermal bonding is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; and preferably a reinforcement z i thermal bonding is a polyolefin elastomer and / or coumarone-indene resin.

[0050] In a preferred embodiment of the present invention, the polyolefin elastomer is preferably an elastomer of ethylene copolymerized with propylene and / or an α-olefin, the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or the coumarone-indene resin is a hydrogenated C5 and / or C9 coumarone-indene resin with a softening point of 100-150°C; preferably a cyclopentadiene type resin.

[0051] According to the present invention, the melt flow rate of the enhancer z ithermal bonding can be selected within wide limits, and the enhancer z is preferable i thermal bonding has a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, preferably 1-18 g / 10 min, and more preferably 3-18 g / 10 min.

[0052] In a preferred embodiment of the present invention, the random copolymer of polypropylene x i and random copolymer of polypropylene β i have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or a melt flow rate difference at 230°C and a load of 2.16 kg of less than 10 g / 10 min, preferably less than 5 g / 10 min, more preferably less than 3 g / 10 min; and / or a molecular weight distribution difference of less than 3, preferably less than 2, and more preferably less than 1. Even more preferably, the random copolymer of polypropylene x iand random copolymer of polypropylene β i are the same.

[0053] In a preferred embodiment of the present invention, the polypropylene homopolymer a i and polypropylene homopolymer γ i have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or a melt flow rate difference at 230°C and a load of 2.16 kg of less than 10 g / 10 min, preferably less than 5 g / 10 min, more preferably less than 3 g / 10 min; and / or a stereoregularity difference (mm) of less than 3%, preferably less than 2%, more preferably less than 1%; and even more preferably a polypropylene homopolymer a i and polypropylene homopolymer γ i are the same.

[0054] In a preferred embodiment of the present invention, the amplifier y i thermal bonding and enhancer z ithermal bonding have: a melting point difference or laminar flow temperature difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or a melt flow rate difference at 190°C and a load of 2.16 kg of less than 10 g / 10 min, preferably less than 5 g / 10 min, and more preferably less than 3 g / 10 min. Even more preferably, the reinforcement y i thermal bonding and enhancer z i thermal bonding are the same.

[0055] As a result of the study conducted by the inventors of the present invention, it was found that when the mass flow rates of the melt and the compositional ratios of the polymers in the polypropylene compositions C i , C' i and polypropylene compositions B i , B' iare within the above-mentioned preferred ranges, the low melting point polypropylene random copolymer and the thermal bonding promoter in the composition can significantly reduce the hot pressing temperature and expand the hot pressing temperature window, and the thermal bonding promoter ensures good adhesive properties of the sheet, further improving the tear strength of the intermediate layer.

[0056] In a preferred embodiment of the present invention, the melting point of the polypropylene composition A i greater than the melting point of polypropylene composites C i , C' i and polypropylene compositions B i , B' i , preferably the temperature difference between the respective melting temperatures 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. Preferably, the melting temperature of the polypropylene homopolymer ai in the components of polypropylene composition A i greater than the melting point of the random copolymer of polypropylene β i in polypropylene compositions C i , C' i and the melting point of the random copolymer of polypropylene x i in polypropylene compositions B i , B' i , and the temperature difference between the corresponding melting temperatures is greater than or equal to 10°C.

[0057] According to the present invention, there is no special limitation on the difference in melting point between the polypropylene compositions C i , C' i and polypropylene compositions Bi, B' i .

[0058] As a result of the study conducted by the inventors of the present invention, it was found that when the mass flow rates of the melt, the melting temperature differences, the compositional ratios of the polymers and the thickness distributions of the polymer composition in the polypropylene composition Ai , polypropylene compositions C i , C' i and polypropylene compositions B i , B' i are within the above-mentioned preferred ranges, a smoother sheet preparation process can be achieved, which in turn allows the sheet to have further improved uniformity, tensile strength, impact strength and tear strength of the interlayer.

[0059] According to the present invention, structure B i C i A i C' i B' i layer of polypropylene sheet can be obtained by co-extrusion of components containing polypropylene composition A i , polypropylene compositions C i , C' i and polypropylene compositions B i , B' i .

[0060] According to the present invention, the polypropylene sheet may be a film and may also have a certain thickness. In the present invention, the polypropylene film is one form of the polypropylene sheet.

[0061] According to the present invention, the polypropylene sheet layer is a polypropylene sheet and / or a polypropylene fabric; the polypropylene sheet layer may be a polypropylene sheet, and may also be a polypropylene fabric. In a preferred embodiment of the present invention, the polypropylene sheet layer is a polypropylene sheet or a polypropylene fabric.

[0062] In a preferred embodiment of the present invention, a polypropylene sheet is prepared by coextruding components containing a polypropylene composition A i , polypropylene composition B i , polypropylene composition B' i , an optional polypropylene composition Ci and an optional polypropylene composition C' i .

[0063] In a preferred embodiment of the present invention, a polypropylene fabric is prepared by the following method: first coextruding components containing a polypropylene composition A i , polypropylene composition B i , polypropylene composition B' i , an optional polypropylene composition C i and an optional polypropylene composition C' i to obtain a polypropylene sheet, and then weaving the polypropylene sheet to obtain a polypropylene fabric; wherein preferably the polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0064] According to the present invention, it is preferable that the different layers of the polypropylene sheet are bonded by hot pressing.

[0065] In a preferred embodiment of the present invention, the polypropylene composite material has at least one of the following features:

[0066] The tensile strength in the machine direction is ≥160 MPa, preferably ≥180 MPa; and the tear strength of the intermediate layer is ≥1.3 N / mm, preferably ≥1.5 N / mm.

[0067] The tensile strength in the machine direction is measured according to the method specified in GB / T1040.1-2018, and the tear strength of the intermediate layer is measured according to the method specified in GB / T2358-98. The corresponding specimens in the above two tests are the standard specimens required in the above-mentioned testing standards.

[0068] When the polypropylene composite material is obtained by hot pressing and fusing 5 layers of polypropylene sheet, and the thickness of the polypropylene composite material is approximately 390μm, it has a falling impact strength of ≥42J, preferably ≥45J.

[0069] The drop impact strength is determined according to the method specified in GB / T14153-1993, and the thickness of the specimen is the thickness of the finished product.

[0070] A second object of the present invention is to provide a method for producing the above-described polypropylene composite material, comprising the steps of: sequentially laying 2n-1 groups of layers of polypropylene sheet in the sequence group n,... group i,... group 2, group 1, group 2,... group i,... group n, and then performing hot pressing and fusing.

[0071] In the embodiment where each group of polypropylene layers comprises only 1 polypropylene layer, the method of preparation comprises the steps of: sequentially laying 2n-1 layers of polypropylene sheet with a B structure i A i B' i in accordance with order 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 , and then hot pressing and fusing.

[0072] In the embodiment where each group of polypropylene layers comprises 2 or more layers of polypropylene sheet, the manufacturing method comprises the steps of: sequentially laying down layers of polypropylene sheet of each group of layers of polypropylene sheet, then sequentially laying down 2n-1 groups of layers of polypropylene sheet in the sequence group n,... group i,... group 2, group 1, group 2,... group i,... group n, and then performing hot pressing and fusing.

[0073] In a preferred embodiment of the present invention, the preparation method comprises the following steps:

[0074] (1) Polypropylene composition A i , polypropylene composition B i and polypropylene composition B' i , optional polypropylene composition C i , optional polypropylene composition C' i coextruded, cast or calendered, and stretched according to structure Bi A i B' i or structure B i C i A i C' i B' i in order to obtain a polypropylene sheet;

[0075] (2) Optionally, the polypropylene sheet is divided and cut, and then woven to obtain the polypropylene fabric of B structure i A i B' i or B i C i A i C' i B' i ;

[0076] (3) The polypropylene sheet and / or polypropylene fabric are successively stacked, hot pressed and fused, and then cooled and molded to form a polypropylene composite material.

[0077] In a preferred embodiment of the present invention, in step (1), preparing the polypropylene composition Ai comprises melt-blending raw materials such as components containing at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer. Conditions and equipment for melt-blending the polypropylene composition A i The prior art polyolefin melt mixing conditions and equipment are used, preferably the melting temperature is 190-240°C, and the equipment is preferably a twin-screw extruder.

[0078] In a preferred embodiment of the present invention, in step (1) preparing polypropylene compositions B i , B' icomprises melt-blending raw materials such as components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; conditions and equipment for melt-blending polypropylene compositions B i , B' i The prior art polyolefin melt mixing conditions and equipment are used, preferably the melting temperature is 190-240°C, and the equipment is preferably a twin-screw extruder.

[0079] In a preferred embodiment of the present invention, in step (1) preparing polypropylene compositions C i , C' i comprises melt-blending raw materials such as components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; conditions and equipment for melt-blending polypropylene compositions C i , C'i The prior art polyolefin melt mixing conditions and equipment are used, preferably the melting temperature is 190-240°C, and the equipment is preferably a twin-screw extruder.

[0080] In a preferred embodiment of the present invention, in step (1), the co-extrusion molding and casting temperatures are independently selected from 200-240°C; and / or the calendering temperature is 50-70°C.

[0081] In a preferred embodiment of the present invention, the stretching conditions comprise: a stretching temperature of 90-165°C, preferably 90-140°C, more preferably 90-119°C; and / or a stretching ratio of 1-15, preferably 2-9.

[0082] In a preferred embodiment of the present invention, the polypropylene sheet obtained in step (1) has a width of 2-5 mm.

[0083] In a preferred embodiment of the present invention, in step (3), the hot pressing conditions comprise: a hot pressing temperature of 115-170°C, preferably 115-159°C, more preferably 140-159°C; a hot pressing pressure of 2-10 MPa, a preheating time of 5-600 s, and a hot pressing time of 1-600 s, preferably 10-500 s.

[0084] In a preferred embodiment of the present invention, the pressure for cooling and molding is 2-8 MPa, and the cooling time is 30-700 s.

[0085] In a preferred embodiment of the present invention, the stacked adjacent polypropylene fabrics are arranged at an angle of 0-90 degrees relative to each other along their respective warp directions; and / or the stacked adjacent polypropylene sheets are arranged at an angle of 0-90 degrees relative to each other along their respective machine directions, where the machine direction is the stretch direction (MD).

[0086] In a more preferred embodiment of the present invention, a method for preparing a polypropylene composite material comprises the following steps:

[0087] Stage A: Polypropylene Composition A i , polypropylene composition B i and polypropylene composition B' i , optional polypropylene composition C i , optional polypropylene composition C' i coextruded, cast or calendered according to structure Bi A i B' i or structure B i C i A i C' i B' i in order to obtain coextruded polypropylene sheet; preferably, the temperature of coextrusion, casting or calendering is 200-230°C, and the temperature of the calender is 50-70°C;

[0088] Step b: The coextruded polypropylene sheet is subjected to solid-phase stretching at a certain temperature to obtain a stretched polypropylene film or a stretched polypropylene sheet; preferably, the stretching temperature is 90-165°C, preferably 90-140°C, more preferably 90-119°C, and the stretch ratio is 1-15;

[0089] Step c: the stretched polypropylene film or stretched polypropylene sheet is divided and cut to prepare polypropylene tapes and weave the tapes to obtain a polypropylene fabric; preferably, the width of the polypropylene tape is 2-5 mm, and the structure of the polypropylene fabric includes, but is not limited to, plain weave, twill weave, satin weave and / or other weaves;

[0090] Step d: The stretched polypropylene film, sheet or fabric is laid in the sequence of group n... group I... group 2, group 1, group 2... group I... group n, in the direction from bottom to top, and the total number of laid groups is 2n-1, where n>=2.Polypropylene sheets or fabrics are hot pressed and fused, and then cooled and molded to obtain a polypropylene composite material; the hot pressing temperature is preferably 110-180°C, preferably 115-170°C, and more preferably 130-160°C; the hot pressing pressure is 2-10 MPa, the heating time is 5-600 s, the hot pressing time is 1-600 s, preferably 10-500 s, the cooling pressure is 2-8 MPa, and the cooling time is 30-700 s; preferably, the polypropylene sheets in the polypropylene composite material are arranged at an angle of 0-90 degrees relative to each other along their respective machine directions, and the polypropylene fabrics in the polypropylene composite material are arranged at an angle of 0-90 degrees relative to each other along their respective warp directions.

[0091] A third object of the present invention is to provide a continuous hot pressing molding system for a polypropylene composite material of the present invention, shown in Fig. 1, comprising a preheater 1, a track-type continuous flat hot press 2, a track-type continuous flat cold press 3, a sheet cutting machine 4 and a sheet stacking machine 5, arranged in series;

[0092] Preferably, the track-type continuous flat hot press 3 comprises a heating unit 6, an independent heating and pressing unit 7, an air cooling unit 8 and a lifting mechanism 9.

[0093] According to the present invention, in a preferred specific embodiment, the pressure is preferably maintained continuously during the hot pressing and cooling process, and does not decrease, and the hot pressing process is carried out continuously, preferably as shown in Fig. 1, wherein equipment for continuously molding a composite by hot pressing is used, consisting of a preheater 1, a track-type continuous flat hot press 2, a track-type continuous flat cold press 3, machines 4 for cutting sheets 4 and a sheet stacking machine 5; preferably, the track-type continuous flat hot press 2 has a heating unit 6, an independent heating and pressing unit 7, an air cooling unit 8 and a lifting mechanism 9.During the preparation, stretched polypropylene films, sheets, and / or fabrics are successively stacked and then heated by a heater 1, and the heated samples are successively subjected to hot pressing and fusion by a tracked flat hot press 2, and then cooled and formed by a tracked flat cold press 3 to obtain a polypropylene composite material, i.e., a multilayer hot-pressed product. After this, the hot-pressed product is cut as needed by a sheet-cutting machine 4, and then stacked by a sheet-stacking machine 5. In this case, the hot-pressing temperature is maintained by a heating unit 6, an independent heating and pressing unit 7, and an air cooling unit 8 in a tracked continuous flat hot press 2, and the hot-pressing pressure is controlled by a lifting mechanism 9.

[0094] As a result of the study conducted by the inventors of the present invention, it was found that when the parameters of the preparation method are within the above-mentioned preferred ranges, and more preferably the preparation equipment is used to produce the polypropylene composite material, the polypropylene composite material has better tensile strength, impact properties and tear strength of the intermediate layer.

[0095] A fourth object of the present invention is to provide the use of the described polypropylene composite material and the polypropylene composite material prepared by the above-described method in applications of consumer goods, automobile manufacturing, sports protection and military materials.

[0096] According to a specific embodiment of the present invention, the field of application includes the baggage and transportation industry, the footwear industry, the automobile industry, the sports equipment industry, the audio equipment industry, and the military field.

[0097] A fifth object of the present invention is to provide a polypropylene sheet preferably used as a polypropylene sheet layer in the above-described polypropylene composite material, that is, as a polypropylene sheet layer in a self-reinforced polymer composite material comprising a layer A and layers B and B' arranged on both sides of layer A, with a BAB' structure; wherein layer A contains a polypropylene composition A, layer B is the same as or different from layer B', layer B contains a polypropylene composition B, and layer B' contains a polypropylene composition B', and the melting point of the polypropylene composition A is higher than the melting point of the polypropylene composition B and the polypropylene composition B'; wherein the polypropylene composition A contains a polypropylene homopolymer a and a polypropylene block copolymer b;each of the polypropylene composition B and the polypropylene composition B' comprises a random copolymer of polypropylene x and a thermal bonding enhancer y; and preferably the random copolymer of polypropylene x has a molecular weight distribution Mw / Mn of 5-12, preferably 7-10.

[0098] In a preferred embodiment of the present invention, the polypropylene sheet further comprises layers C, C' with a BCAC'B' structure; layer C is the same as or different from layer C', layer C comprises a polypropylene composition C, and layer C' comprises a polypropylene composition C'; the melting point of the polypropylene composition A is higher than the melting point of the polypropylene composition C and the polypropylene composition C'; wherein each of the polypropylene composition C and the polypropylene composition C' comprises a polypropylene β random copolymer, a polypropylene γ homopolymer, and a thermal bonding enhancer z; and preferably, the polypropylene β random copolymer has a molecular weight distribution Mw / Mn of 5-12, preferably 7-10.

[0099] All the features described above regarding the polypropylene sheet layer also apply to the polypropylene sheet. The features described regarding layers A i , Bi , B i ', C i and C i ' layers of polypropylene sheet, apply to layers A, B, B', C and C' of the polypropylene sheet, respectively; the features described with respect to polypropylene compositions A i , B i , B i ', C i and C i ' layers of polypropylene sheet, applicable to polypropylene compositions A, B, B', C and C' of polypropylene sheet, respectively; the features described with respect to polypropylene homopolymer a i , polypropylene block copolymer b i , random copolymer of polypropylene xi, thermal bonding enhancer yi, random copolymer of polypropylene β i , polypropylene homopolymer γ i and amplifier z ithermal bonding layer of polypropylene sheet, are applicable to polypropylene homopolymer a, polypropylene block copolymer b, polypropylene random copolymer x, thermal bonding enhancer y, polypropylene random copolymer β, polypropylene homopolymer γ and thermal bonding enhancer z of polypropylene sheet, respectively.

[0100] In a preferred embodiment of the present invention, the melting point of the polypropylene composition A is greater than the melting point of the polypropylene compositions B and B'; preferably, the melting point of the polypropylene homopolymer a in the polypropylene composition A exceeds the melting point of the random copolymer of polypropylene x in the polypropylene compositions B and B', and preferably the difference in the respective melting points is greater than or equal to 10°C.In this preferred embodiment, the inventors of the present invention have unexpectedly found that the resulting polypropylene sheets are hot pressed to produce a polypropylene composite material having more superior mechanical properties and at the same time having a higher tear strength of the intermediate layer, and even at a lower hot pressing temperature and a wider range of hot pressing temperatures, the tear strength of the intermediate layer of the resulting polypropylene composite material is higher.

[0101] As a result of the study conducted by the inventors of the present invention, it was found that when the melt mass flow rates, the composition ratios of the polymers in the polypropylene composition A and the polypropylene compositions B, B', and the thickness distribution of the film layer A are within the preferred ranges, a smoother sheet preparation process can be achieved, which in turn allows the sheet to have further improved uniformity, tensile strength, impact strength, and tear strength of the intermediate layer.

[0102] The BAB' structure of the polypropylene sheet can be prepared by various methods. In a preferred embodiment of the present invention, the BAB' structure of the polypropylene sheet is obtained by coextruding components containing the polypropylene composition A and the polypropylene compositions B, B'.

[0103] In a preferred embodiment of the present invention, the melting point of the polypropylene composition A is greater than the melting point of the polypropylene compositions B, B' and the polypropylene compositions C, C', preferably the temperature difference between the respective melting points 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. Preferably, the melting point of the polypropylene homopolymer a in the components of the polypropylene composition A is greater than the melting point of the polypropylene random copolymer β in the polypropylene compositions B, B' and the melting point of the polypropylene random copolymer x in the polypropylene compositions C, C', and the temperature difference between the respective melting points is greater than or equal to 10°C.

[0104] According to the present invention, there is no special limitation on the difference in melting temperatures between the polypropylene compositions B, B' and the polypropylene compositions C, C'.

[0105] As a result of the study conducted by the inventors of the present invention, it was found that when the mass flow rates of the melt, the melting temperature differences, the composition ratios of the polymers and the thickness distributions of the polymer composition in the polypropylene composition A, the polypropylene compositions B, B' and the polypropylene compositions C, C' are within the above-mentioned preferred ranges, a smoother sheet preparation process can be ensured, which in turn allows the sheet to have improved uniformity, tensile strength, impact strength and tear strength of the intermediate layer.

[0106] According to the present invention, a BCAC'B' structure of a polypropylene composite material sheet is obtained by coextruding components containing a polypropylene composition A, polypropylene compositions B, B' and polypropylene compositions C, C'.

[0107] The sixth object of the present invention is to provide a method for producing the above-described polypropylene sheet, comprising: molding by coextruding, casting or calendering a polypropylene composition A, a polypropylene composition B, a polypropylene composition B', an optional polypropylene composition C, an optional polypropylene composition C', and stretching according to the structure BAB' or BCAC'B' in order to obtain a polypropylene sheet.

[0108] In a preferred embodiment of the present invention, preparing the polypropylene composition A comprises melt-blending components comprising a polypropylene homopolymer a and a polypropylene block copolymer b; and / or preparing the polypropylene compositions B, B' comprises melt-blending components comprising a polypropylene random copolymer x and a thermal bonding enhancer y; and / or preparing the polypropylene compositions C, C' comprises melt-blending components comprising a thermal bonding enhancer z, a polypropylene random copolymer β and a polypropylene homopolymer γ; and / or the molding temperatures by coextrusion and casting are independently selected from the range of 200-240°C; and / or the calender temperature is 50-70°C; and / or the stretching conditions comprise: a stretching temperature of 90-165°C, preferably 90-140°C, more preferably 90-119°C; and an elongation coefficient of 1-15, preferably 2-9.

[0109] According to some embodiments of the present invention, the polypropylene composition A, the polypropylene composition B, the polypropylene composition B', the optional polypropylene composition C and the optional polypropylene composition C' are coextruded and cast or calendered according to the structure BAB' or BCAC'B' to obtain a coextruded polypropylene sheet. The process of the extrusion-calendering method may comprise sequentially passing the coextruded polypropylene sheet through a calendering roll and a drawing roll, and then subjecting it to solid-phase stretching, edge trimming and rolling to prepare sheets. Here, the extrusion and casting temperature is 200-230°C, and the temperature of the calendering roll is 50-70°C.The specific method of preparing the film by extrusion-calendering is a common choice in the art and will not be described in further detail.

[0110] All the features described above regarding the method of preparing the polypropylene sheet layer also apply to the method of preparing the polypropylene sheet.

[0111] The seventh object of the present invention is to provide a three-dimensional polypropylene fabric obtained by interweaving the above-described polypropylene sheets; preferably, this polypropylene fabric has a spatial structure of plain weave, twill weave and / or satin weave.

[0112] In order to facilitate weaving, it is preferable to cut the PP sheet to obtain 2-5mm wide PP sheet strips, and then weave them to obtain PP fabric.

[0113] 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 coextruded and stretched polypropylene tape, and the three-layer coextruded and stretched polypropylene tape comprises a layer A formed from a polypropylene composition A with a high melting point, and layers B, B' formed from polypropylene compositions B, B' with low melting points, wherein the polypropylene composition A comprises a polypropylene homopolymer a and a polypropylene block copolymer b; the polypropylene compositions B, B' comprise a random copolymer of polypropylene x and a thermal bonding enhancer y, and the three-layer polypropylene fabric has a BAB' structure in the bottom-up direction.

[0114] 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 five-layer coextruded and stretched polypropylene tape, and this coextruded and stretched polypropylene tape comprises a layer A formed from a polypropylene composition A with a high melting point, intermediate layers C, C' formed from polypropylene compositions C, and layers B, B' formed from a polypropylene composition B with a low melting point, wherein the polypropylene composition A comprises a polypropylene homopolymer a and a polypropylene block copolymer b; the polypropylene compositions C, C' comprise a thermal bonding enhancer z, a random copolymer of polypropylene β and a homopolymer of polypropylene γ;polypropylene compositions B, B' contain a random copolymer of polypropylene x and a thermal bonding enhancer y, and the five-layer polypropylene fabric has a BCAC'B' structure in the bottom-up direction.;

[0115] All the features described above regarding the PP sheet layer and PP sheet also apply to PP fabric.

[0116] The eighth object of the present invention is to provide a polypropylene composite material prepared using a plurality of layers of the above-described polypropylene sheets and / or the above-described polypropylene fabrics by hot pressing and fusing; preferably, the polypropylene fabrics are laid at an angle of 0-90 degrees relative to each other along their respective warp directions from top to bottom, the number of layers is preferably 2 or more, more preferably 2-200; and most preferably 4-100. The polypropylene sheets are laid at an angle of 0-90 degrees relative to each other along their respective machine directions from top to bottom, the number of layers is preferably 2 or more, more preferably 2-200; and most preferably 4-100.

[0117] In a preferred embodiment of the present invention, the polypropylene compositions A contained in each layer of the stacked polypropylene fabrics may be the same or different, and the polypropylene fabrics A contained in each layer may be independently selected, preferably the polypropylene compositions A in each layer are the same.

[0118] In a preferred embodiment of the present invention, the polypropylene composite material has at least one of the following features:

[0119] Machine direction tensile strength ≥150MPa, preferably ≥170MPa;

[0120] Tear strength of intermediate layer ≥1N / mm, preferably ≥1.2N / mm.

[0121] The tensile strength is measured according to the method specified in GB / T1040.1-2018, and the tear strength of the intermediate layer is measured according to the method specified in GB / T2358-98. The corresponding specimens in the above two tests are the standard specimens required in the above-mentioned testing standards.

[0122] When the polypropylene composite material is obtained by hot pressing and fusing 24 layers of polypropylene fabrics, and its thickness is approximately 1.6mm, it has a falling impact strength of ≥228J, preferably ≥240J.

[0123] The drop impact strength is determined according to the method specified in GB / T14153-1993, and the thickness of the specimen is the thickness of the finished product.

[0124] According to the present invention, when the polypropylene composite material sheet has a BCAC'B' structure, the polypropylene composite material has at least one of the following features:

[0125] The tensile strength in the machine direction (MD) is ≥150 MPa, preferably ≥170 MPa; and the tear strength of the intermediate layer is ≥1.1 N / mm, preferably ≥1.3 N / mm. When the composite is obtained by hot pressing and fusing 24 layers of polypropylene fabrics, and its thickness is approximately 1.8 mm, it has a falling impact strength of ≥240 J, preferably ≥250 J.

[0126] The ninth object of the present invention is to provide a method for preparing the above-described polypropylene composite material, comprising laying, hot pressing and fusing polypropylene sheets and / or polypropylene fabrics, and then cooling and molding them to obtain polypropylene composite materials.

[0127] In a preferred embodiment of the present invention, the hot pressing and fusing temperature is 115-170°C, preferably 115-159°C, and more preferably 140-159°C.

[0128] In a preferred embodiment of the present invention, the hot pressing and fusing pressure is 2-10 MPa.

[0129] In a preferred embodiment of the present invention, the preheating time of hot pressing and fusing is 5-600 s, and the hot pressing time is 1-600 s, preferably 10-500 s.

[0130] In a preferred embodiment of the present invention, the pressure for cooling and molding is 2-8 MPa, and the cooling and molding time is 30-700 s.

[0131] In a preferred embodiment of the present invention, the number of layers of polypropylene sheets and / or polypropylene fabrics is 2 or more, preferably 2-200; and more preferably 4-100.

[0132] In a preferred embodiment of the present invention, adjacent layers in a stack of polypropylene sheets are arranged at an angle of 0-90 degrees relative to each other along their respective machine directions (MD).

[0133] In a preferred embodiment of the present invention, adjacent layers in a stack of polypropylene fabrics are arranged at an angle of 0-90 degrees relative to each other along their respective warp directions.

[0134] In a more preferred embodiment of the present invention, a method for preparing a high-strength and impact-resistant polypropylene composite material comprises the following steps:

[0135] Step a: The polypropylene composition A and the polypropylene compositions B, B' are coextruded, cast or calendered according to the structure BAB' to obtain a coextruded polypropylene sheet; preferably, the coextrusion, casting or calendering temperature is 200-240°C, and the calendering temperature is 50-70°C;

[0136] Step b: The co-extruded polypropylene sheet is stretched at a certain temperature to obtain a stretched polypropylene sheet; preferably, the stretching temperature is 90-165°C, preferably 90-140°C, more preferably 90-119°C, and the stretch ratio is 1-15, preferably 2-9.

[0137] Step c: The stretched polypropylene sheet is divided and cut to prepare polypropylene tapes and weaving these tapes to obtain polypropylene fabric; preferably, the width of the polypropylene tape is 2-5mm, and the polypropylene fabric comprises plain weave, twill weave, satin weave or other three-dimensional polypropylene fabrics;

[0138] Step d: the polypropylene fabric is successively laid down, hot pressed and fused, and then cooled and molded to obtain a polypropylene composite material; preferably, the hot pressing conditions in step d include: a hot pressing temperature of 115-170°C, preferably 115-159°C, and more preferably 140-159°C; a hot pressing pressure of 2-10 MPa, a preheating time of 5-600 s, a hot pressing time of 1-600 s, preferably 10-500 s, a cooling pressure of 2-8 MPa and a cooling time of 30-700 s; preferably, adjacent polypropylene fabrics in the polypropylene composite material can be arranged at an angle of 0-90 degrees with respect to each other along their respective warp directions.

[0139] According to some embodiments of the present invention, the cutting in step c can be performed using a high-speed cutting and dividing machine with multiple blades to produce oriented polypropylene tapes having a width of 2-5 mm. These oriented tapes are woven according to the designed fabric structure using a commercial weaving machine to produce plain, twill, satin weave polypropylene fabrics and / or other three-dimensional polypropylene fabrics.

[0140] In a more preferred embodiment of the present invention, a method for preparing a polypropylene composite material comprises the following steps:

[0141] step a: the polypropylene composition A, the polypropylene compositions C, C' and the polypropylene compositions B, B' are coextruded, cast or calendered according to the structure BCAC'B' to obtain a coextruded polypropylene sheet; preferably, the extrusion, casting or calendering temperature is 200-230°C, and the calendering temperature is 50-70°C;

[0142] Step b: The co-extruded polypropylene sheet is stretched at a certain temperature to obtain a stretched polypropylene sheet; preferably, the stretching temperature is 90-165°C, preferably 90-140°C, more preferably 90-119°C, and the stretch ratio is 1-15;

[0143] Step c: The stretched polypropylene sheet is divided and cut to prepare polypropylene tapes and weaving these tapes to obtain polypropylene fabric; preferably, the width of the polypropylene tape is 2-5mm, and the polypropylene fabric comprises plain weave, twill weave, satin weave or other three-dimensional polypropylene fabrics;

[0144] step d: a polypropylene sheet or fabric is sequentially laid down, hot pressed and fused, and then cooled and molded to obtain a polypropylene composite material; preferably, the hot pressing conditions include: a hot pressing temperature of 115-170°C, preferably 115-159°C, and more preferably 140-159°C; a hot pressing pressure of 2-10 MPa, a preheating time of 5-300 s, a hot pressing time of 1-300 s, preferably 1-9 s or 61-100 s, a cooling pressure of 2-8 MPa and a cooling time of 30-700 s; wherein, in the polypropylene composite material, the polypropylene fabrics may be arranged at an angle of 0-90 degrees with respect to each other along their respective warp directions; and / or sheets of polypropylene composite material are arranged at an angle of 0-90 degrees relative to each other along their respective machine directions.

[0145] According to the present invention, in a preferred specific embodiment, the pressure is preferably maintained continuously during the hot pressing and cooling process and does not decrease, and the hot pressing process is carried out continuously, preferably using continuous hot pressing composite molding equipment consisting of a preheater, a track-type continuous flat hot press, a track-type continuous flat cold press, a sheet cutting machine and a sheet stacking machine; preferably, the track-type continuous flat hot press has a preheating unit, an independent heating and pressing unit, an air cooling unit and a lifting mechanism.

[0146] In the preparation process, polypropylene sheets and / or fabrics are stacked sequentially and then heated by a preheater. The heated samples are then hot-pressed and fused by a track-type flat hot press. They are then cooled and molded by a track-type flat cold press to form a polypropylene composite material, i.e., a multilayer hot-pressed product. The hot-pressed product is then cut as needed by a sheet-cutting machine and then stacked by a sheet-stacking machine. The hot-pressing temperature is maintained by a preheating unit, an independent heating and pressing unit, and an air cooling unit in the track-type continuous flat hot press. The hot-pressing pressure is controlled by a lifting mechanism.As a result of the study conducted by the inventors of the present invention, it was found that when the parameters of the preparation method are within the preferred ranges and the preferred preparation equipment is used to produce the polypropylene composite material, the polypropylene composite material has better tensile strength, impact properties and tear strength of the intermediate layer.

[0147] The tenth object of the present invention is to provide the use of the above-described polypropylene sheet, polypropylene fabric, polypropylene composite material and polypropylene composite material prepared by the above-described preparation method in applications of sports protection, automobile manufacturing, consumer goods and military materials.

[0148] According to a specific embodiment of the present invention, the field of application includes the baggage and transportation industry, the footwear industry, the automobile industry, the sports equipment industry, the audio equipment industry, and the military field.

[0149] Compared with the prior art, the present invention has the following advantageous effects:

[0150] (1) The polypropylene composite material of the present invention has a melting temperature gradient structure, and the inventors of the present invention unexpectedly found that, due to such a structure, the resulting polypropylene composite material has good tensile strength, impact properties and tear strength of the intermediate layer at the same time.

[0151] In particular, when the polypropylene composite material sheets have a BAB' sheet structure, the polypropylene composite materials have the following features: a tensile strength in the machine direction (MD) of ≥150 MPa, preferably ≥170 MPa; a tear strength of the intermediate layer of ≥1 N / mm, preferably ≥1.2 N / mm; and when the composite is obtained by hot pressing and fusing 24 layers of polypropylene fabrics, and its thickness is approximately 1.6 mm, it has a drop impact strength of ≥228 J, preferably ≥240 J.

[0152] In particular, when the polypropylene composite material sheets have a BCAC'B' sheet structure, the polypropylene composite materials have the following features: tensile strength in the machine direction (MD) ≥150 MPa, preferably ≥170 MPa; and tear strength of the intermediate layer ≥1.1 N / mm, preferably ≥1.3 N / mm. When the composite is obtained by hot pressing and fusing 24 layers of polypropylene fabrics, and its thickness is approximately 1.8 mm, it has a falling impact strength of ≥240 J, preferably ≥250 J.

[0153] (2) The polypropylene composite material of the present invention can be produced at a lower hot-pressing temperature and a wider hot-pressing temperature range. The hot-pressing temperature range can effectively reduce equipment energy consumption and damage to the composite material due to high temperatures. At the same time, the composite still has good tear strength of the interlayer when produced at a lower hot-pressing temperature.

[0154] (3) This preparation method can shorten the hot pressing time while improving the production efficiency and reducing the energy consumption in production.

[0155] (4) The present invention uses a melting temperature gradient structure, which reduces the hot pressing temperature and expands the hot pressing temperature range, which can reach 70°C; it effectively reduces the energy consumption of the equipment and the damage to the composite material due to high temperatures.

[0156] The present invention also relates to the following embodiments:

[0157] 1. A polypropylene composite material comprising a plurality of sequentially laid polypropylene layers, each polypropylene layer comprising a core layer A i and outer layers B i and B' i , located on both sides of the main layer A i , with structure B i A i B' i ; the structure of the polypropylene composite material is B n A n B' n ……B i A i B' i ……B2A2B'2, B1A1B'1, B2A2B'2……B i Ai B' i ……B n A n B' n , in the direction from bottom to top, the total number of laid polypropylene layers is 2n-1; i and n are integers not less than 2, and i≤n;

[0158] where the main layer is A i in the polypropylene layer contains a polypropylene composition A i , outer layer B i is the same as or different from the outer layer B' i , outer layer B i contains polypropylene composition B i , and the outer layer B' i contains polypropylene composition B' i ,

[0159] melting point of polypropylene composition A i greater than the melting point of polypropylene composition B i and polypropylene composition B' i ; melting point of polypropylene composition B i and polypropylene composition B' igreater than the melting point of their respective adjacent polypropylene composition B' i-1 and polypropylene composition B i-1 .

[0160] 2. The polypropylene composite material according to embodiment 1, characterized in that:

[0161] each of the difference between the melting point of the polypropylene composition A i and the melting point of the polypropylene composition Bi and the difference between the melting point of the polypropylene composition A i and the melting temperature of the polypropylene composition B' i greater than or equal to 10°C, more preferably greater than or equal to 20°C; and / or

[0162] difference between the melting point of polypropylene composition B i and polypropylene composition B' i , as well as between the melting temperature of the corresponding adjacent polypropylene composition B' i-1 and polypropylene composition B i-1are the same or different, and each is 1-40°C, preferably 1-10°C, and more preferably 1-5°C.

[0163] 3. The polypropylene composite material according to embodiment 1, characterized in that: 2≤n≤100, preferably 2≤n≤50.

[0164] 4. The polypropylene composite material according to embodiment 1, characterized in that:

[0165] Base layer thickness A i in each polypropylene layer is 51-89% of the total thickness of the polypropylene layer, preferably 71-89%, and more preferably 71-80%.

[0166] 5. The polypropylene composite material according to embodiment 1, characterized in that:

[0167] Polypropylene composition A i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or

[0168] each of the polypropylene compositions B i and B' icontains one or more of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; preferably a polypropylene composition B i and / or polypropylene composition B' i also contains the y amplifier i thermal bonding.

[0169] 6. The polypropylene composite material according to embodiment 5, characterized in that:

[0170] Polypropylene composition A i contains polypropylene homopolymer a i and polypropylene block copolymer b i ;

[0171] preferably polypropylene composition A i contains 50-99 wt.% of polypropylene homopolymer a i , 1-50 wt. % polypropylene block copolymer b i ; more preferably a polypropylene composition A i contains 70-90 wt.% of polypropylene homopolymer a i , 10-30 wt. % polypropylene block copolymer b iby total weight of polypropylene composition A i ; and / or

[0172] each of the polypropylene compositions B i and B' i contains a random copolymer of polypropylene x i and amplifier y i thermal bonding;

[0173] preferably each of the polypropylene compositions B i and B' i contains 70-99 wt.% random copolymer of polypropylene x i and 1-30 wt.% of the enhancer y i thermal bonding; more preferably polypropylene composition B i contains 80-90 wt.% random copolymer of polypropylene x i and 10-20 wt.% of the enhancer y i thermal bonding by total weight of each polypropylene composition B i or B' i .

[0174] 7. The polypropylene composite material according to embodiment 6, characterized in that:

[0175] polypropylene homopolymer a ihas a melting point of 150-170°C; and / or

[0176] polypropylene homopolymer a i has a stereoregularity (mm) of at least 96%; and / or

[0177] block copolymer polypropylene b i has a melting point of 150-170°C; and / or

[0178] the monomer copolymerizable with propylene in the polypropylene block copolymer is ethylene or butene, preferably butene; and / or

[0179] polypropylene block copolymer has an Izod impact strength of at least 20 kJ / m 2 .

[0180] 8. The polypropylene composite material according to embodiment 6, characterized in that:

[0181] polypropylene random copolymer x i has a melting point of 110-150°C, and the melting point of x i greater than the melting point x i-1 , preferably the melting point difference between them is 1-40°C, more preferably 1-10°C, and most preferably 1-5°C; and / or

[0182] polypropylene random copolymer x i is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer.

[0183] 9. The polypropylene composite material according to embodiment 6, characterized in that:

[0184] amplifier y i thermal bonding has a melting point or laminar flow temperature of 70-110°C; and / or

[0185] amplifier y i thermal bonding is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA, and a coumarone-indene resin;

[0186] preferably amplifier y i thermal bonding is a polyolefin elastomer and / or coumarone-indene resin.

[0187] 10. The polypropylene composite material according to embodiment 9, characterized in that:

[0188] the polyolefin elastomer is an elastomer of ethylene copolymerized with propylene and / or an α-olefin, the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or

[0189] The coumaroneindene resin is a hydrogenated C5 and / or C9 coumaroneindene resin with a softening point of 100-150°C; and is preferably a cyclopentadiene type resin.

[0190] 11. The polypropylene composite material according to embodiment 5, characterized in that:

[0191] Polypropylene composition A i also contains a β-nucleating agent; preferably

[0192] the β-nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, two-component complexes of Group IIA, aromatic diamides, rare earth metal compounds, and cyclic dicarboxylate nucleating agents; and / or

[0193] content of β-nucleating agent in polypropylene composition A i is 0.01-0.5 m. parts per 100 m. parts of the total amount of polypropylene composition A i .

[0194] 12. A polypropylene composite material according to one of embodiments 1-11, characterized in that:

[0195] the polypropylene sheet layer is a polypropylene sheet and / or a polypropylene fabric; preferably, the polypropylene sheet layer is a polypropylene sheet and / or a polypropylene fabric; more preferably

[0196] The polypropylene sheet is prepared by coextruding components containing polypropylene composition A i , polypropylene composition B i and polypropylene composition B' i ; and / or

[0197] The polypropylene fabric is prepared by first co-extruding components containing polypropylene composition A i, polypropylene composition B i and polypropylene composition B' i in order to obtain a polypropylene sheet, and then weaving the polypropylene sheet to obtain a polypropylene fabric; wherein preferably the polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0198] 13. The polypropylene composite material according to embodiment 12, characterized in that:

[0199] Different layers of PP sheet are bonded by hot pressing.

[0200] 14. The method for preparing a polypropylene composite material according to one of embodiments 1-13 comprises the steps of: sequentially laying 2n-1 layers of a polypropylene sheet with a B structure i A i B' i in accordance with order B n A n B' n ……B i A i B' i ……B2A2B'2, B1A1B'1, B2A2B'2……B iA i B' i ……B n A n B' n , and then hot pressing and fusing.

[0201] 15. The method of preparation according to embodiment 14, characterized in that it comprises the following steps:

[0202] (1) Polypropylene composition A i , polypropylene composition B i and polypropylene composition B' i coextruded, cast or calendered, and stretched according to structure B i A i B' i in order to obtain a polypropylene sheet;

[0203] (2) Optionally, the polypropylene sheet is divided and cut, and then woven to obtain the polypropylene fabric of B structure i A i B' i ;

[0204] (3) The polypropylene sheet and / or polypropylene fabric are successively stacked and hot pressed, and then cooled and molded to form a polypropylene composite material.

[0205] 16. The method of preparation according to embodiment 15, characterized in that:

[0206] Preparation of polypropylene composition A i in step (1) comprises melt-blending components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or

[0207] Preparation of polypropylene composition B i in step (1) comprises melt-blending components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or

[0208] the co-extrusion and casting temperatures in step (1) are independently selected from the range of 200-240°C; and / or

[0209] the calender temperature at step (1) is 50-70°C; and / or

[0210] the stretching temperature in step (1) is 90-165°C, preferably 90-140°C, and more preferably 90-119°C; and / or

[0211] The stretching degree at stage (1) is 1-15.

[0212] 17. The method of preparation according to embodiment 15, characterized in that:

[0213] at stage (3):

[0214] hot pressing conditions comprise: hot pressing temperature of 115-170°C, preferably 115-159°C, more preferably 140-159°C; hot pressing pressure of 2-10 MPa, preheating time of 5-600 s, and hot pressing time of 1-600 s, preferably 10-500 s; and / or

[0215] cooling and forming pressure 2-8 MPa and cooling time 30-700 s; and / or

[0216] adjacent polypropylene fabrics to be stacked are arranged at an angle of 0-90 degrees relative to each other along their respective warp directions; and / or

[0217] The adjacent polypropylene sheets are stacked at an angle of 0-90 degrees to each other along their respective machine directions.

[0218] 18. A continuous hot-press molding system for a polypropylene composite material described in any one of embodiments 1 to 13, comprising a preheater, a track-type continuous flat hot press, a track-type continuous flat cold press, a sheet cutting machine, and a sheet stacking machine arranged in series;

[0219] The preferably track-type continuous flat hot press comprises a preheating unit, an independent heating and pressing unit, an air cooling unit and a lifting mechanism.

[0220] 19. Use of the polypropylene composite material described in any one of embodiments 1-13 and the polypropylene composite material prepared by the method described in any one of embodiments 14-17 in consumer goods, automobile manufacturing, sports protection and military material applications.

[0221] DESCRIPTION OF DRAWINGS

[0222] Fig. 1 is a schematic diagram of the arrangement of process equipment used in a preferred embodiment of the present invention.

[0223] Here 1 is a preheater; 2 is a crawler-type continuous flat hot press; 3 is a crawler-type continuous flat cold press; 4 is a sheet cutting machine; 5 is a sheet stacking machine; The crawler-type continuous flat hot press 2 has a preheating unit 6, an independent heating and pressing unit 7, an air cooling unit 8 and a lifting mechanism 9.

[0224] DETAILED DESCRIPTION

[0225] Next, the present invention will be described in more detail with reference to the following accompanying drawings and examples. It should be noted that the following examples are intended only to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention, and some minor modifications and adjustments made to the present invention by those skilled in the art are still within the protection scope of the present invention.

[0226] The properties of polypropylene composites and sheets were tested according to the following methods, and the product test results are shown in Table 1:

[0227] (1) Melt mass flow rate (MFR): determined according to the method specified in GB / T 3682-2000, in which, for polypropylene (including polypropylene homopolymer, polypropylene block copolymer and polypropylene random copolymer), the test temperature is 230°C and the load is 2.16kg; for the thermal bonding promoter, the test temperature is 190°C and the load is 2.16kg.

[0228] (2) Molecular weight distribution (Mw / Mn): determined according to the method described in GB / T 36214.1-2018, where Mw is the weight-average molecular weight, g / mol, and Mn is the number-average molecular weight, g / mol.

[0229] (3) Melting point of the material: determined according to the method specified in GB / T 28724-2012. The mass of the sample was 5 mg, and the temperature was increased from 50°C to 230°C at a rate of 10°C / min, held at 230°C for 3 min to eliminate the thermal history, decreased from 230°C to 50°C at a rate of 10°C / min, held at 50°C for 1 min, and finally increased from 50°C to 230°C at a rate of 10°C / min, and the last heating curve was used to determine the melting point or melting point range of the material.

[0230] (4) Sheet tensile strength: determined in accordance with the method specified in GB / T1040.1-2018.

[0231] (5) Drop impact strength: determined in accordance with the method specified in GB / T14153-1993.

[0232] (6) Tear strength of intermediate layer: determined in accordance with the method specified in GB / T2358-98.

[0233] The following examples used β-crystal nucleating agent VP101B grade from Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation; the sources of some raw materials are described in the examples, and the rest of the raw materials are commercially available unless otherwise explicitly stated.

[0234] Example A1

[0235] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

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

[0237] Component a was a polypropylene homopolymer prepared by Beijing Research Institute of Chemical Industry (SINOPEC), with a melting point of 160°C, a melt flow rate (melt mass flow rate) of 3.2g / 10min, and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC, with an ethylene content of 11 wt%, a melting point of 155°C, and an Izod impact strength of 23kJ / m 2 (at 23°C) and a melt flow rate of 2.0 g / 10 min. The components prepared above were weighed and mixed in a proportion in which the mass fraction Wa of component a was 80 parts by weight, and the mass fraction Wb of component b was 20 parts by weight.

[0238] VP101B β-nucleating agent was added at a rate of 0.05 ppm. The mixture was then added to a high-speed mixer and uniformly mixed. The mixed material was then fed into the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During processing, the screw temperature was maintained at 200-230°C. The material was melted and uniformly mixed by the screw, extruded, tableted, and dried to obtain polypropylene composition A tablets with a melting point of 157°C.

[0239] (2) Preparation of polypropylene composition B i :

[0240] component x1 was a polypropylene random copolymer prepared by Beijing Scientific Institute of Chemical Industry (SINOPEC), which 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 °C; component x2 was a polypropylene random copolymer prepared by SINOPEC, which 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 °C; component x3 was a random copolymer of polypropylene prepared by SINOPEC, which was 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°C;and component y was ExxonMobil 6102 polyolefin elastomer, a copolymer of ethylene and propylene.

[0241] The above prepared components were weighed and mixed in a proportion in which the mass fraction of Wx i component x i was 85 phr, the mass fraction Wy of component y was 15 phr, the other steps were the same as step (1), and finally, tablets of polypropylene composition B were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 127°C, the melting point of B2 was 132°C, and the melting point of B3 was 138°C.

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

[0243] Polypropylene composition A and polypropylene composition B tablets i, prepared in the above steps (1) and (2), were dried, after which the polypropylene composition A was added to the base layer extruder of the multilayer extrusion-calendering machine, and the polypropylene composition B i was added to the upper and lower layer extruders of a multilayer extrusion-calendering machine. After coextrusion, compounding, and flowing through the extruder die, the tablets were sequentially passed through a calendering roll and a drawing roll, and then subjected to solid-state stretching, edge trimming, and rolling to prepare B1AB1, B2AB2, and B3AB3 sheets, respectively. The extrusion and casting temperatures were 230°C, and the calendering roll temperature was 58°C. During solid-state stretching, the temperature was 140°C, the stretching speed was 2 m / min, and the stretch ratio was 7.

[0244] The composite film (polypropylene sheet) prepared after stretching and rolling was composed of a top surface layer (B film i outer layer), base layer (film A) and bottom surface layer (film B i outer layer). The thickness of the composite film was 80 µm, with the thickness of film layer A accounting for 80% of the total sheet thickness.

[0245] (4) Preparation of polypropylene fabrics:

[0246] The three-layer coextruded polypropylene sheets prepared in the above step (3) were separated and cut into 3mm-wide oriented polypropylene tapes using a high-speed multi-blade slitting and dividing machine. The oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to obtain plain weave polypropylene fabrics of B1AB1, B2AB2, and B3AB3.

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

[0248] The polypropylene fabrics prepared in the above-mentioned step (4) were sequentially laid in the sequence B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3 from bottom to top, with a total number of laid layers of 5, and the laid polypropylene fabrics were hot pressed and fused, cooled, and molded into a polypropylene composite material. The polypropylene fabrics were laid at an angle of 90 degrees with respect to each other along their respective warp directions. The hot pressing conditions used were: temperature of 145°C, hot pressing pressure of 5 MPa, preheating time of 90 s, hot pressing time of 90 s, and cooling time of 300 s. The thickness of the prepared polypropylene composite material was 391 μm.

[0249] Example A2

[0250] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

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

[0252] Component a was a polypropylene homopolymer prepared by Beijing Research Institute of Chemical Industry (SINOPEC) with a melting point of 165°C, a melt flow rate of 8.1g / 10min, and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC with an ethylene content of 8 wt%, a melting point of 155°C, a melt flow rate of 3.2g / 10min, and an Izod impact strength of 25kJ / m 2 (at 23°C). The components prepared above were weighed and mixed in a proportion in which the mass fraction Wa of component a was 70 phr, and the mass fraction Wb nThe component b was 30 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. After that, the mixture was added to a high-speed mixer and mixed uniformly, the mixed material was added to the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and mixed uniformly by the screw, extruded, tableted and dried to obtain tablets of polypropylene composition A with a melting point of 161°C.

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

[0254] component x1 was a polypropylene random copolymer prepared by Beijing Scientific Institute of Chemical Industry (SINOPEC), which was an ethylene-propylene-butene terpolymer, with a molecular weight distribution (Mw / Mn) of 8.4, a melting point of 128°C, and a melt flow rate of 7.8g / 10min; component x2 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer, with a molecular weight distribution (Mw / Mn) of 7.6, a melting point of 134°C, and a melt flow rate of 6.9g / 10min; component x3 was a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.1, a melting point of 142°C and a melt flow rate of 5.2 g / 10 min and;and component y was a polyolefin elastomer prepared by SINOPEC, which was a copolymer of ethylene and propylene, with an ethylene content of 15 wt.%, a melting point of 105°C and a melt flow rate of 9 g / 10 min under a load of 2.16 kg;

[0255] The above prepared components were weighed and mixed in a proportion in which the mass fraction Wx i component x i was 80 phr, the mass fraction Wy of component y was 20 phr, the other steps were the same as step (1), and finally, tablets of polypropylene composition B were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 126°C, the melting point of B2 was 133°C, and the melting point of B3 was 140°C.

[0256] (3) Preparation of three-layer coextruded polypropylene sheets:

[0257] The preparation method was the same as that in step (3) of Example A1.

[0258] (4) Preparation of polypropylene fabrics:

[0259] The preparation method was the same as that in step (4) of Example A1.

[0260] (5) Preparation of polypropylene composite material:

[0261] The preparation method was the same as that in step (5) of Example A1.

[0262] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0263] Example A3

[0264] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0265] (1) Preparation of polypropylene composition A:

[0266] The procedure was carried out as in Example A1, wherein the mass fraction Wa of component a was 90 phr, and the mass fraction Wb of component b was 10 phr. β-nucleating agent VP101B was added in an amount of 0.05 phr. Tablets of polypropylene composition A were obtained. When tested, the melting point of the tablets of polypropylene composition A was 158°C.

[0267] (2) Preparation of polypropylene composition B i :

[0268] It was carried out as in Example A1, with the mass fraction Wx i corresponding component x i was 90 m.p., the mass fraction Wy of component y was 10 m.p., and tablets of polypropylene composition B were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 128°C, the melting point of B2 was 134°C, and the melting point of B3 was 139°C.

[0269] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0270] The preparation method was the same as that in step (3) of Example A1.

[0271] (4) Preparation of polypropylene fabrics:

[0272] The preparation method was the same as that in step (4) of Example A1.

[0273] (5) Preparation of polypropylene composite material:

[0274] The preparation method was the same as that in step (5) of Example A1.

[0275] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0276] Example A4

[0277] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0278] (1) Preparation of polypropylene composition A:

[0279] The preparation method was the same as that in step (1) of Example A1.

[0280] (2) Preparation of polypropylene composition B i :

[0281] The preparation method was the same as that in step (2) of Example A1.

[0282] (3) Preparation of three-layer coextruded polypropylene sheets:

[0283] The main steps were the same as in Example A1. The thickness of the polypropylene sheets was 80 μm, and the thickness of the film layer A accounted for 90% of the total sheet thickness.

[0284] (4) Preparation of polypropylene fabrics:

[0285] The preparation method was the same as that in step (4) of Example A1.

[0286] (5) Preparation of polypropylene composite material:

[0287] The preparation method was the same as that in step (5) of Example A1.

[0288] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0289] Example A5

[0290] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0291] (1) Preparation of polypropylene composition A:

[0292] The preparation method was the same as that in step (1) of Example A1.

[0293] (2) Preparation of polypropylene composition B i :

[0294] The preparation method was the same as that in step (2) of Example A1.

[0295] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0296] The main steps were the same as in Example A1. The thickness of the polypropylene sheets was 80 μm, and the thickness of the film layer A accounted for 70% of the total sheet thickness.

[0297] (4) Preparation of polypropylene fabrics:

[0298] The preparation method was the same as that in step (4) of Example A1.

[0299] (5) Preparation of polypropylene composite material:

[0300] The preparation method was the same as that in step (5) of Example A1.

[0301] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0302] Example A6

[0303] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0304] (1) Preparation of polypropylene composition A:

[0305] The preparation method was the same as that in step (1) of Example A1.

[0306] (2) Preparation of polypropylene composition B i :

[0307] The preparation method was the same as that in step (2) of Example A1.

[0308] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0309] The preparation method was the same as that in step (3) of Example A1.

[0310] (4) Preparation of polypropylene fabrics:

[0311] The main steps were the same as step (4) of Example A1. Oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to produce polypropylene satin weave fabrics.

[0312] (5) Preparation of polypropylene composite material:

[0313] The preparation method was the same as that in step (5) of Example A1.

[0314] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0315] Example A7

[0316] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0317] (1) Preparation of polypropylene composition A:

[0318] The preparation method was the same as that in step (1) of Example A1.

[0319] (2) Preparation of polypropylene composition B i :

[0320] The preparation method was the same as that in step (2) of Example A1.

[0321] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0322] The basic preparation method was the same as that in step (3) of Example A1. In this case, the sheet stretch ratio was 10.

[0323] (4) Preparation of polypropylene fabrics:

[0324] The preparation method was the same as that in step (4) of Example A1.

[0325] (5) Preparation of polypropylene composite material:

[0326] The preparation method was the same as that in step (5) of Example A1.

[0327] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0328] Example A8

[0329] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0330] (1) Preparation of polypropylene composition A:

[0331] The preparation method was the same as that in step (1) of Example A1.

[0332] (2) Preparation of polypropylene composition B i :

[0333] The preparation method was the same as that in step (2) of Example A1.

[0334] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0335] The preparation method was the same as that in step (3) of Example A1.

[0336] (4) Preparation of polypropylene fabrics:

[0337] The preparation method was the same as that in step (4) of Example A1.

[0338] (5) Preparation of polypropylene composite material:

[0339] The basic preparation method was the same as that in step (5) of Example A1. In this case, the polypropylene fabrics were laid at an angle of 45 degrees to each other along their respective warp directions.

[0340] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0341] Example A9

[0342] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0343] (1) Preparation of polypropylene composition A:

[0344] The preparation method was the same as that in step (1) of Example A1.

[0345] (2) Preparation of polypropylene composition B i :

[0346] The preparation method was the same as that in step (2) of Example A1.

[0347] (3) Preparation of three-layer coextruded polypropylene sheets:

[0348] The preparation method was the same as that in step (3) of Example A1.

[0349] (4) Preparation of polypropylene fabrics:

[0350] The preparation method was the same as that in step (4) of Example A1.

[0351] (5) Preparation of polypropylene composite material:

[0352] The basic preparation method was the same as that in step (5) of Example A1. In this case, the polypropylene fabrics were laid at an angle of 0 degrees relative to each other along their respective warp directions.

[0353] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0354] Example A10

[0355] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0356] (1) Preparation of polypropylene composition A:

[0357] Proceeded as in Example A1 except that no β-nucleating agent was added to component A.

[0358] (2) Preparation of polypropylene composition Bi:

[0359] It was carried out in the same way as in Example A1.

[0360] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0361] The preparation method was the same as that in step (3) of Example A1.

[0362] (4) Preparation of polypropylene fabrics:

[0363] The preparation method was the same as that in step (4) of Example A1.

[0364] (5) Preparation of polypropylene composite material:

[0365] The preparation method was the same as that in step (5) of Example A1.

[0366] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0367] Example A11

[0368] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0369] (1) Preparation of polypropylene composition A:

[0370] Component a was a polypropylene homopolymer prepared by Beijing Research Institute of Chemical Industry (SINOPEC), with a melting point of 160°C, a melt flow rate (melt mass flow rate) of 3.2g / 10min, and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC, with an ethylene content of 11 wt%, a melting point of 155°C, and an Izod impact strength of 23kJ / m 2 (at 23°C) and a melt flow rate of 2.0 g / 10 min. The components prepared above were weighed and mixed in a proportion in which the mass fraction Wa of component a was 80 parts by weight, and the mass fraction Wb of component b was 20 parts by weight.

[0371] VP101B β-nucleating agent was added at a rate of 0.05 ppm. The mixture was then added to a high-speed mixer and uniformly mixed. The mixed material was then fed into the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During processing, the screw temperature was maintained at 200-230°C. The material was melted and uniformly mixed by the screw, extruded, tableted, and dried to obtain polypropylene composition A tablets with a melting point of 157°C.

[0372] (2) Preparation of polypropylene composition B:

[0373] The α component was ExxonMobil 6102 polyolefin elastomer, which is an ethylene-propylene copolymer with an ethylene content of 16 mass% (the melt flow rate at 190°C and a load of 2.16 kg was 1.4 g / 10 min); the β1 component was a polypropylene random copolymer prepared by Beijing Scientific Institute of Chemical Industry (SINOPEC), which 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°C; component β2 was a random copolymer of polypropylene prepared by SINOPEC, which 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°C;Component β3 was a polypropylene random copolymer prepared by SINOPEC, which was 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°C; component γ was a polypropylene homopolymer prepared by SINOPEC with a melt flow rate of 3.2 g / 10 min, a melting point of 160°C and a stereoregularity of 97%.

[0374] The above prepared components were weighed and mixed in a proportion in which the mass fraction Wα of the α component was 45 phr, the mass fraction Wβ of the β component was 45 phr, Wγ was 10 phr, other steps were the same as step (1), and finally, polypropylene composition tablets B were obtained i (that is, α+β i +γ=B i, i=1, 2, 3). According to the testing results, the melting point of B1 was 129°C, the melting point of B2 was 136°C, and the melting point of B3 was 141°C.

[0375] (3) Preparation of polypropylene composition C:

[0376] component x1 was a polypropylene random copolymer prepared by Beijing Scientific Institute of Chemical Industry (SINOPEC), which 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 °C; component x2 was a polypropylene random copolymer prepared by SINOPEC, which 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 °C; component x3 was a random copolymer of polypropylene prepared by SINOPEC, which was 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°C;and component y was ExxonMobil 6102 polyolefin elastomer, a copolymer of ethylene and propylene.

[0377] The above prepared components were weighed and mixed in a proportion in which the mass fraction of Wx i component x i was 85 phr, the mass fraction Wy of component y was 15 phr, the other steps were the same as step (1), and finally, tablets of polypropylene composition C were obtained i (that is, x i +y=C i , i=1, 2, 3). According to the testing results, the melting point of C1 was 127°C, the melting point of C2 was 132°C, and the melting point of C3 was 138°C.

[0378] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0379] The tablets of polypropylene composition A, polypropylene composition B, and polymer C prepared in the above steps (1), (2), and (3) were dried, after which the polypropylene composition A was added to the base layer extruder of a multi-layer extrusion-calendering machine, the polypropylene composition B was added to the middle layer extruders of a multi-layer extrusion-calendering machine, and the polypropylene composition C was added to the upper and lower surface layer extruders of a multi-layer extrusion-calendering machine. After coextrusion, compounding, and flowing through the extruder die, the tablets were successively passed through a calendering roll and a drawing roll, and then subjected to solid-phase stretching, edge trimming, and rolling to prepare sheets. The extrusion and casting temperature was 230°C, and the calendering roll temperature was 60°C.During solid-state stretching, the temperature was 138°C, the stretching speed was 2 m / min, and the stretching ratio was 7.

[0380] The polypropylene composite material sheet (composite film) obtained after stretching and rolling was composed of an upper surface layer (C film layer i ), middle layer (film layer B i ), the main layer (film layer A i ), middle layer (film layer B i ) and the lower surface layer (film layer C i ). The thickness of the polypropylene composite sheets was 80 µm, and the thickness of the film layer A i was 80% of the total sheet thickness, film thickness B i was 10% of the total sheet thickness, and the film thickness C i amounted to 10% of the total sheet thickness.

[0381] (5) Preparation of polypropylene fabrics:

[0382] The preparation method was the same as that in step (5) of Example A1.

[0383] (6) Preparation of polypropylene composite material:

[0384] The preparation method was the same as that in step (6) of Example A1.

[0385] The thickness of the prepared polypropylene composite material was similar to Example A1.

[0386] Example A12

[0387] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0388] (1) Preparation of polypropylene composition A:

[0389] The preparation method was the same as that in step (1) of Example A1.

[0390] (2) Preparation of polypropylene composition B:

[0391] The basic preparation method was the same as that in step (2) of Example A1. Except that the material of component B i and x i was selected as follows:

[0392] component x1 was a polypropylene random copolymer prepared by Beijing Research Institute of Chemical Industry (SINOPEC), which was an ethylene-propylene-butene terpolymer with a melting point of 110°C; component x2 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 115°C; component x3 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 120°C; component x4 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 125°C; component x5 was a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 130°C;component x6 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 135°C; component x7 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 140°C; component x8 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 145°C; and component x9 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 150°C; wherein the molecular weight distributions Mw / Mn of components x1-x9 were all in the range of 7-10, and the melt flow rates of components x1-x9 were all in the range of 1-20 g / 10 min.

[0393] Finally, the polypropylene composition B tablets were obtained i (that is, x i +y=Bi , i=1, 2, 3, 4, 5, 6, 7, 8, 9). As a result of the testing, the melting point of B1 was 110°C, the melting point of B2 was 113°C, the melting point of B3 was 117°C, the melting point of B4 was 123°C, the melting point of B5 was 127°C, the melting point of B6 was 133°C, the melting point of B7 was 137°C, the melting point of B8 was 142°C, and the melting point of B9 was 148°C.

[0394] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0395] The preparation method was the same as that in step (3) of Example A1.

[0396] (4) Preparation of polypropylene fabrics:

[0397] The preparation method was the same as that in step (4) of Example A1.

[0398] (5) Preparation of polypropylene composite material:

[0399] The polypropylene fabrics prepared in the above step (4) were sequentially laid out in the sequence B9A9B9… B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3, …B9A9B9from bottom to top, with a total number of layers being 17, and the laid polypropylene fabrics were hot pressed and fused, cooled, and molded into a polypropylene composite material. The polypropylene fabrics were laid at an angle of 90 degrees to each other along their respective warp directions. The hot pressing conditions used were: temperature 150°C, hot pressing pressure 5 MPa, heating time 300 s, hot pressing time 180 s, and cooling time 600 s. The thickness of the finished polypropylene composite material was 1.24 mm.

[0400] Example A13

[0401] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0402] (1) Preparation of polypropylene composition A:

[0403] The preparation method was the same as that in step (1) of Example A1.

[0404] (2) Preparation of polypropylene composition B:

[0405] The basic preparation method was the same as that in step (2) of Example A1. Except that the material of component B i and x i was selected as follows:

[0406] Components x1-x3 were polypropylene random copolymer prepared by Beijing Institute of Chemical Industry (SINOPEC), which is an ethylene-propylene-butene terpolymer with a melting point of 110°C; components x4-x6 were polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 130°C; components x7-x9 were polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 150°C; and the molecular weight distributions Mw / Mn of components x1-x9 were all in the range of 7-10, and the melt flow rates of components x1-x9 were all in the range of 1-20g / 10min.

[0407] Finally, the polypropylene composition B tablets were obtained i (that is, x i +y=B i, i=1, 2, 3, 4, 5, 6, 7, 8, 9…27). According to the testing results, the melting point of B1-B3 was 110°C, the melting point of B4-B6 was 127°C, and the melting point of B7-B9 was 148°C.

[0408] (3) Preparation of three-layer coextruded polypropylene sheets:

[0409] The preparation method was the same as that in step (3) of Example A1.

[0410] (4) Preparation of polypropylene fabrics:

[0411] The preparation method was the same as that in step (4) of Example A1.

[0412] (5) Preparation of polypropylene composite material:

[0413] The polypropylene fabrics prepared in the above step (4) were sequentially laid out in the sequence B9A9B 9…B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3, …B9A9B9from bottom to top, with a total number of layers being laid down of 17, and the laid polypropylene fabrics were hot pressed and fused, cooled, and molded into a polypropylene composite material. The polypropylene fabrics were laid at an angle of 90 degrees to each other along their respective warp directions. The hot pressing conditions used were: temperature of 150°C, hot pressing pressure of 5 MPa, preheating time of 300 s, hot pressing time of 180 s, and cooling time of 600 s. The thickness of the prepared polypropylene composite material was 1.24 mm.

[0414] Example A14

[0415] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0416] (1) Preparation of polypropylene composition A:

[0417] The preparation method was the same as that in step (1) of Example A1.

[0418] (2) Preparation of polypropylene composition B:

[0419] The preparation method was the same as that in step (2) of Example A1.

[0420] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0421] The preparation method was the same as that in step (3) of Example A1.

[0422] (4) Preparation of polypropylene fabrics:

[0423] The preparation method was the same as that in step (4) of Example A1.

[0424] (5) Preparation of polypropylene composite material:

[0425] The main steps were the same as in Example A1. Except that the hot pressing conditions were changed to: temperature 150°C, hot pressing pressure 8MPa, preheating time 180s, hot pressing time 180s, and cooling time 700s. The thickness of the prepared polypropylene composite material was 387μm.

[0426] Example A15

[0427] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0428] (1) Preparation of polypropylene composition A:

[0429] The preparation method was the same as that in step (1) of Example A1.

[0430] (2) Preparation of polypropylene composition B:

[0431] The main preparation method was the same as that in step (2) of Example A1, except that the component B material i and x i was selected as follows:

[0432] Component x1 was a polypropylene random copolymer prepared by Beijing Scientific Institute of Chemical Industry (SINOPEC), which was an ethylene-propylene-butene terpolymer with a melting point of 110°C; component x2 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 130°C; and component x3 was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 150°C. Meanwhile, the molecular weight distributions Mw / Mn of components x1-x3 were all in the range of 7-10, and the melt flow rates of components x1-x3 were all in the range of 1-20g / 10min.

[0433] Finally, the polypropylene composition B tablets were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 110°C, the melting point of B2 was 128°C, and the melting point of B3 was 147°C.

[0434] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0435] The preparation method was the same as that in step (3) of Example A1.

[0436] (4) Preparation of polypropylene fabrics:

[0437] The preparation method was the same as that in step (4) of Example A1.

[0438] (5) Preparation of polypropylene composite material:

[0439] The preparation method was the same as that in step (5) of Example A1.

[0440] The thickness of the prepared PP composite material was similar to Example A1.

[0441] Example A16

[0442] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0443] (1) Preparation of polypropylene composition A:

[0444] The preparation method was the same as that in step (1) of Example A1.

[0445] (2) Preparation of polypropylene composition B:

[0446] The preparation method was the same as that in step (2) of Example A1.

[0447] (3) Preparation of three-layer coextruded polypropylene sheets:

[0448] The preparation method was the same as that in step (3) of Example A1.

[0449] (4) Preparation of polypropylene composite material:

[0450] Instead of preparing polypropylene fabrics, the three-layer coextruded polypropylene sheets obtained in step (3) (replacing the polypropylene fabrics obtained in step (4) in Example A1) were sequentially laid up and hot pressed in accordance with step (5) in Example A1.

[0451] The thickness of the obtained polypropylene composite materials was similar to Example A1.

[0452] Example A17

[0453] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0454] (1) Preparation of polypropylene composition A:

[0455] The preparation method was the same as that in step (1) of Example A1.

[0456] (2) Preparation of polypropylene composition B:

[0457] The basic preparation method was the same as that in step (2) of Example A1. Except that the material of component B i and x i was selected as follows:

[0458] Components x1-x3 were polypropylene random copolymer prepared by Beijing Institute of Chemical Industry (SINOPEC), which is an ethylene-propylene-butene terpolymer with a melting point of 110°C; components x4-x6 were polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 115°C; components x7-x9 were polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 120°C; components x 10 -x 12were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 125°C; components x 13 -x 15 were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 130°C; components x 16 -x 18 were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 135°C; components x 19 -x 21 were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 140°C; components x 22 -x 24 were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 145°C; and components x 25 -x27 were a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a melting point of 150°C; with all molecular weight distributions Mw / Mn of the components x1-x 27 were in the range of 7-10, and all melt flow rates of components x1-x 27 were in the range of 1-20 g / 10 min.

[0459] Finally, the tablets of polypropylene composition B were obtained i (that is, x i +y=B i , i=1, 2, 3, 4, 5, 6, 7, 8, 9...27). As a result of testing, the melting point of B1-B3 was 110°C, the melting point of B4-B6 was 113°C, the melting point of B7-B9 was 117°C, the melting point of B 10 -B 12 was 123°C, melting point B 13 -B 15 was 127°C, melting point B 16 -B 18 was 133°C, melting point B 19 -B 21 was 137°C, melting point B22 -B 24 was 142°C, and the melting point of B 25 -B 27 amounted to 148°C.

[0460] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0461] The preparation method was the same as that in step (3) of Example A1.

[0462] (4) Preparation of polypropylene fabrics:

[0463] The preparation method was the same as that in step (4) of Example A1.

[0464] (5) Preparation of polypropylene composite material:

[0465] The polypropylene fabrics prepared in the above step (4) were sequentially laid down with sequence B 27 A 27 B 27 ... B9A9B 9… B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3, …B9A9B9… B 27 A 27 B 27The stacked polypropylene fabrics were hot pressed and fused, cooled, and formed into a polypropylene composite material from the bottom up, with a total of 53 layers. The polypropylene fabrics were stacked at 90 degrees to each other along their respective warp directions. The hot pressing conditions used were: temperature 150°C, hot pressing pressure 5 MPa, preheating time 500 s, hot pressing time 360 ​​s, and cooling time 800 s. The thickness of the prepared polypropylene composite material was 3.92 mm.

[0466] Example A18

[0467] Coextruded polypropylene sheets were prepared according to the methods of Example A1, except that the material of component Bi was selected as follows: component x1 was a random copolymer of polypropylene prepared by Beijing Research Institute of Chemical Industry (SINOPEC), which is an ethylene-propylene-butene terpolymer, with a molecular weight distribution (Mw / Mn) of 4.2 and a melting point of 142°C; component x2 was a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer, with a molecular weight distribution (Mw / Mn) of 4.7 and a melting point of 138°C; component x3 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 5.4 and a melting point of 133°C;moreover, all melt flow rates of components x1-x3 were in the range of 2-10 g / 10 min.;

[0468] Finally, the polypropylene composition B tablets were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 139°C, the melting point of B2 was 134°C, and the melting point of B3 was 129°C.

[0469] Comparative Example A1

[0470] Coextruded polypropylene sheets were prepared according to the methods of Example A1, except that the material of component Bi was selected as follows: component x1 was a random copolymer of polypropylene prepared by Beijing Research Institute of Chemical Industry (SINOPEC), which was an ethylene-propylene-butene terpolymer, with a melting point of 140°C; component x2 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer, with a melting point of 135°C; component x3 was a random copolymer of polypropylene prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer, with a melting point of 130°C; Moreover, all molecular weight distributions (Mw / Mn) of components x1-x3 were in the range of 7-10, and all melt flow rates of components x1-x3 were in the range of 2-10 g / 10 min.

[0471] Finally, the tablets of polypropylene composition B were obtained i (that is, x i +y=B i , i=1, 2, 3). According to the testing results, the melting point of B1 was 138°C, the melting point of B2 was 132°C, and the melting point of B3 was 127°C.

[0472] Comparison Example A2

[0473] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example A1, except that the polypropylene composition B i contained only the y component.

[0474] Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example A1.

[0475] Comparison Example A3

[0476] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example A1, except that the thickness of film layer A was 95% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example A1.

[0477] Comparison Example A4

[0478] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example A1, except that the thickness of film layer A was 50% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example A1.

[0479] Comparison Example A5

[0480] Coextruded polypropylene sheets (17 layers) were prepared according to the methods of Example A12, except that the material of component B was selected as follows: all components x1-x9 were polypropylene random copolymer prepared by SINOPEC with a melting point of 110°C; and all molecular weight distributions Mw / Mn of components x1-x9 were in the range of 7-10, and all melt flow rates of components x1-x9 were in the range of 2-10 g / 10 min.

[0481] Finally, the polypropylene composition B tablets were obtained i When testing the melting point of B i amounted to 110°C.

[0482] The hot pressing conditions used were: temperature 150°C, hot pressing pressure 5MPa, heating time 300s, hot pressing time 180s, and cooling time 600s. The thickness of the finished polypropylene composite material was 1.24mm.

[0483] Comparison Example A6

[0484] Coextruded polypropylene sheets (17 layers) were prepared according to the methods of Example A12, except that the material of component Bi was selected as follows: all components x1-x9 were polypropylene random copolymer prepared by SINOPEC with a melting point of 130°C; and all molecular weight distributions Mw / Mn of components x1-x9 were in the range of 7-10, and all melt flow rates of components x1-x9 were in the range of 2-10 g / 10 min.

[0485] Finally, the tablets of polypropylene composition B were obtained i When testing the melting point of B i amounted to 127°C.

[0486] The hot pressing conditions used were: temperature 150°C, hot pressing pressure 5MPa, preheating time 300s, hot pressing time 180s, and cooling time 600s. The thickness of the prepared PP composite material was 1.24mm.

[0487] Comparison Example A7

[0488] Coextruded polypropylene sheets (17 layers) were prepared according to the methods of Example A12, except that the material of component Bi was selected as follows: all components x1-x9 were polypropylene random copolymer prepared by SINOPEC with a melting point of 150°C; and all molecular weight distributions Mw / Mn of components x1-x9 were in the range of 7-10, and all melt flow rates of components x1-x9 were in the range of 2-10 g / 10 min.

[0489] Finally, the polypropylene composition B tablets were obtained i When testing the melting point of B iamounted to 148°C.

[0490] The hot pressing conditions used were: temperature 150°C, hot pressing pressure 5MPa, preheating time 300s, hot pressing time 180s, and cooling time 600s. The thickness of the prepared PP composite material was 1.24mm.

[0491] Experimental Examples

[0492] The polypropylene composite materials obtained in the above Examples and Comparative Examples were tested according to the following methods, and the results are shown in Table 1:

[0493] (1) Tensile strength of sheet: determined in accordance with the method specified in GB / T1040.1-2018;

[0494] (2) Drop impact strength: determined in accordance with the method specified in GB / T14153-1993;

[0495] (3) Interlayer tear strength: determined according to the method described in GB / T2358-98. Meanwhile, all the thicknesses of the polypropylene composite materials obtained in Examples A1-9, 12, 13 and Comparative Examples A1-4 were close to approximately 390 μm, and were in the range of 390 μm ±10 μm.

[0496] Table 1

[0497] № Tensile strength (MPa) Drop impact strength (J) Tear strength (N / mm) Example A1 191 46,91 1,53 Example A2 183 45,72 1,59 Example A3 200 45,48 1,51 Example A4 202 44,04 1,32 Example A5 168 44,75 1,63 Example A6 172 46,11 1,37 Example A7 258 42,17 1,38 Example A8 176 43,59 1,45 Example A9 161 42,14 1,42 Example A10 172 42,25 1,51 Example A11 182 49,32 1,59 Example A12 168 81,62 1,49 Example A13 161 73,85 1,35 Example A14 165 44,43 1,53 Example A15 163 41,21 1,65 Example A16 212 45,67 1,61 Example A17 162 231,83 1,39 Example A18 181 41,28 1,29 Comparative example A1 131 30,89 0,78 Comparative example A2 181 42,55 1,12 Comparative example A3 183 40,16 0,88 Comparative example A4 106 42,23 2,09 Comparative example A5 139 61,34 1,42 Comparative example A6 142 69,58 1,39 Comparative example A7 153 72,49 1,28

[0498] As can be seen from the results of the examples in Table 1, the polypropylene composite materials having a melting temperature gradient structure prepared according to the present invention have good tensile strength and impact resistance properties, and at the same time also have good tear strength of the intermediate layer at a lower hot pressing temperature.

[0499] The polypropylene composite materials having a melting temperature gradient structure described in the present invention have a tensile strength in the machine direction (MD) of ≥160 MPa, a tear strength of the intermediate layer of ≥1.3 N / mm; and when the composite materials are obtained by hot pressing and fusing only 5 layers of polypropylene fabrics and have a thickness of only about 390 μm, they have a drop impact strength of ≥42 J.

[0500] As can be seen from the preferred examples A1-3, the polypropylene composite materials having a melting temperature gradient structure prepared according to the present invention have a tensile strength in the machine direction (MD) of ≥180 MPa, a tear strength of the intermediate layer of ≥1.5 N / mm; and when the composite materials are obtained by hot pressing and fusing only 5 layers of polypropylene fabrics and have a thickness of only about 390 μm, they have a drop impact strength of ≥45 J.

[0501] As can be seen from Comparative Examples A1-8, polypropylene composite materials prepared according to schemes outside the scope of the present invention result in a decrease in the properties of the stacked polypropylene sheets or fabrics, which results in a significant decrease in the tensile strength, impact strength or tear strength of the intermediate layer of the resulting polypropylene composite materials.

[0502] In particular, as can be seen from the comparison of Comparative Examples A5-7 and Example A12, the tensile strength, impact strength, and tear strength of the interlayer of the polypropylene composite materials having a melting point gradient structure according to the present invention are higher than those of conventional polypropylene composite materials without a melting point gradient structure. Compared with conventional polypropylene composite materials without a melting point gradient structure, the polypropylene composite materials according to the present invention having a melting point gradient structure require a shorter hot pressing time or a lower hot pressing temperature for processing.It is believed that shortening the hot pressing time or decreasing the hot pressing temperature can reduce the damage to mechanical properties caused by the disorientation of molecular chains, and, in addition, shortening the hot pressing time or decreasing the hot pressing temperature can achieve the positive effect of reducing costs and improving efficiency.

[0503] Example B1

[0504] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0505] (1) Preparation of polypropylene composition A:

[0506] Component a was a polypropylene homopolymer prepared by SINOPEC with a melting point of 160°C, a melt flow rate (melt mass flow rate) of 3.2g / 10min and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC (with an Izod impact strength of 23kJ / m 2 at 23°C), with an ethylene content of 11 wt.%, a melt flow rate of 2.0 g / 10 min and a melting point of 155°C.

[0507] The components prepared above were weighed and mixed in a proportion in which the mass fraction Wa of component a was 80 phr, and the mass fraction Wb of component b was 20 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. After that, the mixture was added to a high-speed mixer and uniformly mixed, and the mixed material was added to the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During the processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and mixed uniformly by the screw, extruded, tableted and dried to obtain tablets of a polypropylene composition with a melt mass flow rate of 4.6 g / 10 min; and the melting point of the polypropylene composition A was 157°C.

[0508] (2) Preparation of polypropylene composition B:

[0509] component x was a polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.3, a melting point of 140°C, and a melt flow rate of 6.6 g / 10 min; component y was 6102 grade polyolefin elastomer manufactured by ExxonMobil, which is an ethylene-propylene copolymer with an ethylene content of 16 wt% and a melt flow rate at 190°C and a load of 2.16 kg of 1.4 g / 10 min;

[0510] The above-prepared components were weighed and mixed in a proportion in which the mass fraction Wx of component x was 85 phr, the mass fraction Wy of component y was 15 phr, and other steps were the same as step (1). Finally, polypropylene composition B tablets were obtained, which had a melt flow rate of 5.2 g / 10 min and a melting point of 138°C.

[0511] (3) Preparation of three-layer coextruded polypropylene sheets:

[0512] The tablets of polypropylene composition A and polypropylene composition Bi prepared in the above steps (1) and (2) were dried, after which the polypropylene composition A was added to the base layer extruder of the multi-layer extrusion-calendering machine, and the polypropylene composition B was added to the upper and lower layer extruders of the multi-layer extrusion-calendering machine.

[0513] After co-extruding, compounding and flowing out of the extruder die, the tablets were successively passed through the calendering roller and the drawing roller, and then subjected to solid-phase stretching, edge trimming and rolling to prepare a sheet.

[0514] The extrusion and casting temperature was 230°C, and the temperature of the calendering roller was 55°C. During solid-phase stretching, the temperature was 135°C, the stretching speed was 2 m / min, and the stretching ratio was 7. The PP sheet (composite film) obtained after stretching and rolling was composed of an upper surface layer (film layer B), a base layer (film layer A), and a lower surface layer (film layer B).

[0515] The thickness of the above-mentioned PP sheet (composite film) was 80μm, and the thickness of the film layer A accounted for 80% of the total thickness of the sheet.

[0516] (4) Preparation of polypropylene fabrics:

[0517] The three-layer coextruded polypropylene sheets prepared in the above step (3) were separated and cut into 3mm-wide oriented polypropylene tapes using a high-speed multi-blade slitting and dividing machine. The oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to produce plain-weave polypropylene fabrics.

[0518] (5) Preparation of polypropylene composite material:

[0519] The polypropylene fabrics prepared in the above-mentioned step (4) were stacked sequentially and hot pressed to obtain a multilayer polypropylene sheet. This polypropylene sheet contained 24 layers of polypropylene fabrics, and the polypropylene fabrics were arranged at 90 degrees relative to each other along their respective warp directions. The hot pressing conditions used were: temperature of 150°C, hot pressing pressure of 5 MPa, preheating time of 180 s, hot pressing time of 180 s, and cooling time of 600 s. The thickness of the prepared polypropylene composite material was 1.67 mm.

[0520] Example B2

[0521] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0522] (1) Preparation of polypropylene composition A:

[0523] Component a was a polypropylene homopolymer prepared by SINOPEC with a melting point of 165°C, a melt flow rate of 8.1g / 10min and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC (with an Izod impact strength of 25kJ / m 2 at 23°C), with an ethylene content of 8 wt.%, a melt flow rate of 3.2 g / 10 min and a melting point of 155°C.

[0524] The components prepared above were weighed and mixed in a proportion in which the mass fraction Wa of component a was 70 phr, and the mass fraction Wb of component b was 30 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. After that, the mixture was added to a high-speed mixer and uniformly mixed, and the mixed material was added to the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During the processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and mixed uniformly by the screw, extruded, tableted and dried to obtain tablets of a polypropylene composition, with a melt mass flow rate of 7.3 g / 10 min; and the melting point of the polypropylene composition A was 161°C.

[0525] (2) Preparation of polypropylene composition B:

[0526] component x was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a melting point of 134°C, a molecular weight distribution (Mw / Mn) of 7.6, and a melt flow rate of 5.2g / 10min; component y was a polyolefin elastomer prepared by SINOPEC, which was an ethylene-propylene copolymer with an ethylene content of 15% by weight, a melting point of 105°C, and a melt flow rate at 190°C and a load of 2.16kg of 9g / 10min;

[0527] The above-prepared components were weighed and mixed in a proportion in which the mass fraction Wx of component x was 80 phr, the mass fraction Wy of component y was 20 phr, and other steps were the same as step (1). Finally, polypropylene composition B tablets were obtained, which had a melt mass flow rate of 9.6 g / 10 min. The melting point of polypropylene composition B was 130°C.

[0528] (3) Preparation of three-layer coextruded polypropylene sheets:

[0529] The preparation method was the same as that in step (3) of Example B1.

[0530] (4) Preparation of polypropylene fabrics:

[0531] The preparation method was the same as that in step (4) of Example B1.

[0532] (5) Preparation of polypropylene composite material:

[0533] The preparation method was the same as that in step (5) of Example B1.

[0534] The thickness of the prepared PP composite material was similar to Example B1.

[0535] Example B3

[0536] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0537] (1) Preparation of polypropylene composition A:

[0538] The same procedure as in Example B1 was used, with the mass fraction Wa of component a being 90 phr, and the mass fraction Wb of component b being 10 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. Polypropylene composition A tablets with a melt mass flow rate of 6.8 g / 10 min were obtained, and the melting point of the polypropylene composition A was 158°C.

[0539] (2) Preparation of polypropylene composition B:

[0540] It was carried out as in Example B1, wherein the mass fraction Wx of component x was 90 phr, and the mass fraction Wy of component y was 10 phr. Finally, tablets of polypropylene composition B with a mass melt flow rate of 8.7 g / 10 min were obtained, and the melting point of the polypropylene composition B was 139°C.

[0541] (3) Preparation of three-layer coextruded polypropylene sheets:

[0542] The preparation method was the same as that in step (3) of Example B1.

[0543] (4) Preparation of polypropylene fabrics:

[0544] The preparation method was the same as that in step (4) of Example B1.

[0545] (5) Preparation of polypropylene composite material:

[0546] The preparation method was the same as that in step (5) of Example B1.

[0547] The thickness of the prepared polypropylene composite material was similar to Example B1.

[0548] Example B4

[0549] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0550] (1) Preparation of polypropylene composition A:

[0551] The preparation method was the same as that in step (1) of Example B1.

[0552] (2) Preparation of polypropylene composition B:

[0553] The preparation method was the same as that in step (2) of Example B1.

[0554] (3) Preparation of three-layer coextruded polypropylene sheets:

[0555] The main steps were the same as in Example B1. The thickness of the polypropylene sheet was 80 μm, and the thickness of the film layer A accounted for 90% of the total sheet thickness.

[0556] (4) Preparation of polypropylene fabrics:

[0557] The preparation method was the same as that in step (4) of Example B1.

[0558] (5) Preparation of polypropylene composite material:

[0559] The preparation method was the same as that in step (5) of Example B1.

[0560] The thickness of the prepared PP composite material was similar to Example B1.

[0561] Example B5

[0562] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0563] (1) Preparation of polypropylene composition A:

[0564] The preparation method was the same as that in step (1) of Example B1.

[0565] (2) Preparation of polypropylene composition B:

[0566] The preparation method was the same as that in step (2) of Example B1.

[0567] (3) Preparation of three-layer coextruded polypropylene sheets:

[0568] The main steps were the same as in Example B1. The thickness of the polypropylene sheet was 80 μm, and the thickness of the film layer A accounted for 70% of the total sheet thickness.

[0569] (4) Preparation of polypropylene fabrics:

[0570] The preparation method was the same as that in step (4) of Example B1.

[0571] (5) Preparation of polypropylene composite material:

[0572] The preparation method was the same as that in step (5) of Example B1.

[0573] The thickness of the prepared PP composite material was similar to Example B1.

[0574] Example B6

[0575] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0576] (1) Preparation of polypropylene composition A:

[0577] The preparation method was the same as that in step (1) of Example B1.

[0578] (2) Preparation of polypropylene composition B:

[0579] The preparation method was the same as that in step (2) of Example B1.

[0580] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0581] The preparation method was the same as that in step (3) of Example B1.

[0582] (4) Preparation of polypropylene fabrics:

[0583] The main steps were the same as step (4) of Example B1. The oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to produce polypropylene satin weave fabrics.

[0584] (5) Preparation of polypropylene composite material:

[0585] The preparation method was the same as that in step (5) of Example B1.

[0586] The thickness of the prepared PP composite material was similar to Example B1.

[0587] Example B7

[0588] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0589] (1) Preparation of polypropylene composition A:

[0590] The preparation method was the same as that in step (1) of Example B1.

[0591] (2) Preparation of polypropylene composition B:

[0592] The preparation method was the same as that in step (2) of Example B1.

[0593] (3) Preparation of three-layer coextruded polypropylene sheets:

[0594] The basic preparation method was the same as that in step (3) of Example B1. In this case, the sheet stretch ratio was 10.

[0595] (4) Preparation of polypropylene fabrics:

[0596] The preparation method was the same as that in step (4) of Example B1.

[0597] (5) Preparation of polypropylene composite material:

[0598] The preparation method was the same as that in step (5) of Example B1.

[0599] The thickness of the prepared PP composite material was similar to Example B1.

[0600] Example B8

[0601] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0602] (1) Preparation of polypropylene composition A:

[0603] The preparation method was the same as that in step (1) of Example B1.

[0604] (2) Preparation of polypropylene composition B:

[0605] The preparation method was the same as that in step (2) of Example B1.

[0606] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0607] The preparation method was the same as that in step (3) of Example B1.

[0608] (4) Preparation of polypropylene fabrics:

[0609] The preparation method was the same as that in step (4) of Example B1.

[0610] (5) Preparation of polypropylene composite material:

[0611] The basic preparation method was the same as that in step (5) of Example B1. In this case, the polypropylene fabrics were laid at an angle of 45 degrees to each other along their respective warp directions.

[0612] The thickness of the prepared PP composite material was similar to Example B1.

[0613] Example B9

[0614] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0615] (1) Preparation of polypropylene composition A:

[0616] The preparation method was the same as that in step (1) of Example B1.

[0617] (2) Preparation of polypropylene composition B:

[0618] The preparation method was the same as that in step (2) of Example B1.

[0619] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0620] The preparation method was the same as that in step (3) of Example B1.

[0621] (4) Preparation of polypropylene fabrics:

[0622] The preparation method was the same as that in step (4) of Example B1.

[0623] (5) Preparation of polypropylene composite material:

[0624] The basic preparation method was the same as that in step (5) of Example B1. In this case, the polypropylene fabrics were laid at an angle of 0 degrees relative to each other along their respective warp directions.

[0625] The thickness of the prepared PP composite material was similar to Example B1.

[0626] Example B10

[0627] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0628] (1) Preparation of polypropylene composition A:

[0629] The preparation method was the same as that in step (1) of Example B1.

[0630] (2) Preparation of polypropylene composition B:

[0631] The preparation method was the same as that in step (2) of Example B1.

[0632] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0633] The preparation method was the same as that in step (3) of Example B1.

[0634] (4) Preparation of polypropylene fabrics:

[0635] The preparation method was the same as that in step (4) of Example B1.

[0636] (5) Preparation of polypropylene composite material:

[0637] The main steps were the same as in Example B1. The stacked polypropylene sheets contained two layers of polypropylene fabrics. The hot pressing conditions used were: temperature of 140°C, hot pressing pressure of 2 MPa, preheating time of 120 s, hot pressing time of 10 s, and cooling time of 300 s. The thickness of the prepared polypropylene composite material was 128 μm.

[0638] Example B11

[0639] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0640] (1) Preparation of polypropylene composition A:

[0641] The preparation method was the same as that in step (1) of Example B1.

[0642] (2) Preparation of polypropylene composition B:

[0643] The preparation method was the same as that in step (2) of Example B1.

[0644] (3) Preparation of three-layer coextruded polypropylene sheets:

[0645] The preparation method was the same as that in step (3) of Example B1.

[0646] (4) Preparation of polypropylene fabrics:

[0647] The preparation method was the same as that in step (4) of Example B1.

[0648] (5) Preparation of polypropylene composite material:

[0649] The main steps were the same as in Example B1. The stacked polypropylene sheets contained 100 layers of polypropylene fabrics. The hot pressing conditions used were: temperature of 159°C, hot pressing pressure of 10 MPa, preheating time of 300 s, hot pressing time of 300 s, and cooling time of 700 s. The thickness of the prepared polypropylene composite material was 7.23 mm.

[0650] Example B12

[0651] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0652] (1) Preparation of polypropylene composition A:

[0653] The preparation method was the same as that in step (1) of Example B1.

[0654] (2) Preparation of polypropylene composition B:

[0655] The preparation method was the same as that in step (2) of Example B1.

[0656] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0657] The preparation method was the same as that in step (3) of Example B1.

[0658] (4) Preparation of polypropylene fabrics:

[0659] The preparation method was the same as that in step (4) of Example B1.

[0660] (5) Preparation of polypropylene composite material:

[0661] The main steps were the same as in Example B1. The hot pressing conditions used were: temperature 155°C, hot pressing pressure 8 MPa, preheating time 300 s, hot pressing time 300 s, and cooling time 700 s. The thickness of the prepared polypropylene composite material was 1.58 mm.

[0662] Example B13

[0663] This example is used to illustrate the preparation of polypropylene compositions, three-layer coextruded polypropylene sheets, polypropylene fabrics and a polypropylene composite material proposed in the present invention.

[0664] (1) Preparation of polypropylene composition A:

[0665] The preparation method was the same as that in step (1) of Example B1.

[0666] (2) Preparation of polypropylene composition B:

[0667] The preparation method was the same as that in step (2) of Example B1.

[0668] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0669] The preparation method was the same as that in step (3) of Example B1.

[0670] (4) Preparation of polypropylene composite material:

[0671] Instead of preparing polypropylene fabrics, the three-layer coextruded polypropylene sheet obtained in step (3) (replacing the polypropylene fabrics obtained in step (4) in Example B1) was sequentially laid up and hot pressed in accordance with step (5) in Example B1. The thickness of the finished polypropylene composite material was 1.51 mm.

[0672] Example B14

[0673] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0674] (1) Preparation of polypropylene composition A:

[0675] Component a was a polypropylene homopolymer prepared by SINOPEC with a melting point of 160°C, a melt flow rate (melt mass flow rate) of 3.2g / 10min and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC (with an Izod impact strength of 23kJ / m 2 at 23°C), with an ethylene content of 11 wt.%, a melt flow rate of 2.0 g / 10 min and a melting point of 155°C.

[0676] The components prepared above were weighed and mixed in a proportion in which the mass fraction of W a component A was 80 m.h., and the mass fraction of W bThe component a and b were 20 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. After that, the mixture was added to a high-speed mixer and mixed uniformly, the mixed material was added to the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During the processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and mixed uniformly by the screw, extruded, tableted and dried to obtain tablets of a polypropylene composition with a melt mass flow rate of 4.6 g / 10 min; and the melting point of the polypropylene composition A was 157°C.

[0677] (2) Preparation of polypropylene composition C:

[0678] The α component was ExxonMobil 6102 polyolefin elastomer, which is an ethylene-propylene copolymer with an ethylene content of 16 wt% (melt flow rate at 190°C and 2.16 kg load of 1.4 g / 10 min); the β component was a polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.3, a melting point of 140°C, and a melt flow rate of 6.6 g / 10 min; the γ component was a polypropylene homopolymer prepared by SINOPEC with a melt flow rate of 3.2 g / 10 min, a melting point of 160°C, and a stereoregularity of 97%. In this case, the mass fraction Wα of component α was 45 parts by weight, the mass fraction Wβ of component β was 45 parts by weight, and the mass fraction Wγ of component γ was 10 parts by weight., and this mixture was added to a high-speed mixer and uniformly mixed. The mixed material was added to the feeder of a twin-screw extruder manufactured by W&P, through which the material entered the twin-screw extruder. During processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and uniformly mixed by the screw, extruded, tableted and dried to obtain polypropylene composition tablets with a melt mass flow rate of 6.9 g / 10 min; and the melting point of the polypropylene composition C was 145°C.

[0679] (3) Preparation of polypropylene composition B:

[0680] component x was a polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.3, a melting point of 140°C, and a melt flow rate of 6.6 g / 10 min; component y was 6102 grade polyolefin elastomer manufactured by ExxonMobil, which is an ethylene-propylene copolymer with an ethylene content of 16 wt% and a melt flow rate at 190°C and a load of 2.16 kg of 1.4 g / 10 min;

[0681] The above prepared components were weighed and mixed in a proportion in which the mass fraction of W x component x was 85 m.p., mass fraction W y The component y was 15 m.p., and the other steps were the same as step (1). Finally, tablets of polypropylene composition B with a melt mass flow rate of 5.2 g / 10 min were obtained, and the melting point of polypropylene composition B was 138°C.

[0682] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0683] The tablets of polypropylene composition A, polypropylene composition C, and polymer B prepared in the above-mentioned steps (1) and (2) were dried, after which the polypropylene composition A was added to the base layer extruder of a multi-layer extrusion-calendering machine, the polypropylene composition C was added to the middle layer extruders of a multi-layer extrusion-calendering machine, and the polypropylene composition B was added to the upper and lower surface layer extruders of a multi-layer extrusion-calendering machine. After coextrusion, compounding, and flowing through the extruder die, the tablets were successively passed through a calendering roll and a drawing roll, and then subjected to solid-phase stretching, edge trimming, and rolling to prepare the above-described sheets. The extrusion and casting temperature was 230°C, and the calendering roll temperature was 60°C.During solid-state stretching, the temperature was 138°C, the stretching speed was 2 m / min, and the stretching ratio was 7.

[0684] The polypropylene composite material sheet (composite film) prepared after stretching and rolling consisted of an upper surface layer (film layer B), a middle layer (film layer C), a base layer (film layer A), a middle layer (film layer C), and a lower surface layer (film layer B). The thickness of the polypropylene composite material sheet was 80 μm, with the thickness of the film A layer accounting for 80% of the total thickness of the sheet, the thickness of the film C accounting for 10% of the total thickness of the sheet, and the thickness of the film B accounting for 10% of the total thickness of the sheet.

[0685] (5) Preparation of polypropylene fabrics:

[0686] The five-layer coextruded polypropylene composite sheets prepared in step (4) above were separated into 3mm-wide oriented polypropylene tapes using a high-speed multi-blade slitting and cutting machine. The oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to produce plain-weave polypropylene fabrics.

[0687] (6) Preparation of polypropylene composite material:

[0688] The polypropylene fabrics prepared in the above-mentioned step (5) were stacked sequentially and hot pressed to obtain a multilayer polypropylene composite sheet. This polypropylene composite sheet contained 24 layers of polypropylene fabrics, and the polypropylene fabrics were arranged at 90 degrees relative to each other along their respective warp directions. The hot pressing conditions used were: temperature 153°C, hot pressing pressure 5 MPa, heating time 300 s, hot pressing time 180 s, and cooling time 600 s.

[0689] The thickness of the finished polypropylene composite material was 1.82mm.

[0690] Example B15

[0691] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0692] (1) Preparation of polypropylene composition A:

[0693] Component a was a polypropylene homopolymer prepared by Beijing Research Institute of Chemical Industry (SINOPEC), with a melting point of 165°C, a melt flow rate of 8.1g / 10min, and a stereoregularity of 97%; component b was a polypropylene block copolymer prepared by SINOPEC, with an ethylene content of 8 wt%, a melting point of 155°C, and an Izod impact strength of 23kJ / m 8 (at 23°C) and a melt flow rate of 3.2 g / 10 min. The components prepared above were weighed and mixed in a proportion in which the mass fraction of W acomponent A was 70 m.p., and the mass fraction of W b The content of component b was 30 phr. VP101B β-nucleating agent was added in an amount of 0.05 phr. After that, the mixture was added to a high-speed mixer and mixed uniformly, the mixed material was added to the feeder of a W&P twin-screw extruder, through which the material entered the twin-screw extruder. During the processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and mixed uniformly by the screw, extruded, tableted and dried to obtain tablets of a polypropylene composition with a melt mass flow rate of 7.3 g / 10 min. The melting point of polypropylene composition A was 161°C.

[0694] (2) Preparation of polypropylene composition C:

[0695] The α component was a polyolefin elastomer prepared by SINOPEC, which was an ethylene-propylene copolymer with an ethylene content of 15 mass%, a melting point of 105°C, and a melt flow rate at 190°C and a load of 2.16 kg of 9 g / 10 min; the β component was a polypropylene random copolymer prepared by SINOPEC, which was an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.6, a melting point of 134°C, and a melt flow rate of 5.2 g / 10 min; the γ component was a polypropylene homopolymer prepared by SINOPEC, with a melting point of 165°C, a melt flow rate of 8.1 g / 10 min, and a stereoregularity of 97%. In this case, the mass fraction Wα of component α was 55 parts by weight, the mass fraction Wβ of component β was 40 parts by weight, and the mass fraction Wγ of component γ was 5 parts by weight., and this mixture was added to a high-speed mixer and uniformly mixed. The mixed material was added to the feeder of a twin-screw extruder manufactured by W&P, through which the material entered the twin-screw extruder. During processing, the screw temperature was maintained in the range of 200-230°C, the material was melted and uniformly mixed by the screw, extruded, tableted and dried to obtain polypropylene composition tablets with a melt mass flow rate of 7.8 g / 10 min; and the melting point of the polypropylene composition C was 156°C.

[0696] (3) Preparation of polypropylene composition B:

[0697] Component x was a polypropylene random copolymer prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 7.6, a melting point of 134°C, and a melt flow rate of 5.2g / 10min; and component y was a polyolefin elastomer prepared by SINOPEC, which is an ethylene-propylene copolymer with an ethylene content of 15% by weight, a melting point of 105°C, and a melt flow rate at 190°C and a load of 2.16kg of 9g / 10min. The above prepared components were weighed and mixed in a proportion in which the mass fraction of W x component x was 80 m.p., mass fraction W y The component y was 20 m.p., and the other steps were the same as step (1). Finally, tablets of polypropylene composition B with a melt mass flow rate of 9.6 g / 10 min were obtained, and the melting temperature of polypropylene composition B was 130°C.

[0698] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0699] The preparation method was the same as that in step (4) of Example B14.

[0700] (5) Preparation of polypropylene fabrics:

[0701] The preparation method was the same as that in step (5) of Example B14.

[0702] (6) Preparation of polypropylene composite material:

[0703] The preparation method was the same as that in step (6) of Example B14.

[0704] The thickness of the prepared PP composite material was similar to Example B14.

[0705] Example B16

[0706] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0707] (1) Preparation of polypropylene composition A:

[0708] The procedure was carried out as in Example B1, wherein the mass fraction Wa of component a was 90 phr, and the mass fraction Wb of component b was 10 phr. β-nucleating agent VP101B was added in an amount of 0.05 phr. Tablets of polypropylene composition A were obtained. During testing, its melt mass flow rate was 6.8 g / 10 min. The melting point of polypropylene composition A was 158°C.

[0709] (2) Preparation of polypropylene composition C:

[0710] It was carried out as in Example B1, wherein the mass fraction Wα of the α component was 35 phr, the mass fraction Wβ of the β component was 55 phr, and the mass fraction Wγ of the γ component was 10 phr. Finally, tablets of polypropylene composition C with a melt mass flow rate of 7.3 g / 10 min were obtained, and the melting point of the polypropylene composition C was 142°C.

[0711] (3) Preparation of polypropylene composition B:

[0712] It was carried out as in Example B1, with the mass fraction W x component x was 90 m.p., and the mass fraction W y The y component was 10 m.h. Finally, tablets of polypropylene composition B with a melt mass flow rate of 8.7 g / 10 min were obtained, and the melting temperature of polypropylene composition B was 139°C.

[0713] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0714] The preparation method was the same as that in step (4) of Example B14.

[0715] (5) Preparation of polypropylene fabrics:

[0716] The preparation method was the same as that in step (5) of Example B14.

[0717] (6) Preparation of polypropylene composite material:

[0718] The preparation method was the same as that in step (6) of Example B14.

[0719] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0720] Example B17

[0721] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0722] (1) Preparation of polypropylene composition A:

[0723] The preparation method was the same as that in step (1) of Example B14.

[0724] (2) Preparation of polypropylene composition C:

[0725] The preparation method was the same as that in step (2) of Example B14.

[0726] (3) Preparation of polypropylene composition B:

[0727] The preparation method was the same as that in step (3) of Example B14.

[0728] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0729] The main steps were the same as in Example B14, wherein the thickness of film A was 90% of the total sheet thickness, the thickness of film C was 5% of the total sheet thickness, and the thickness of film B was 5% of the total sheet thickness.

[0730] (5) Preparation of polypropylene fabrics:

[0731] The preparation method was the same as that in step (5) of Example B14.

[0732] (6) Preparation of polypropylene composite material:

[0733] The preparation method was the same as that in step (6) of Example B14.

[0734] The thickness of the prepared PP composite material was similar to Example B14.

[0735] Example B18

[0736] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0737] (1) Preparation of polypropylene composition A:

[0738] The preparation method was the same as that in step (1) of Example B14.

[0739] (2) Preparation of polypropylene composition C:

[0740] The preparation method was the same as that in step (2) of Example B14.

[0741] (3) Preparation of polypropylene composition B:

[0742] The preparation method was the same as that in step (3) of Example B14.

[0743] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0744] The main steps were the same as those in Example B14. The thickness of the polypropylene composite material sheets was 80 μm, with the thickness of film A accounting for 70% of the total sheet thickness, the thickness of film C accounting for 15% of the total sheet thickness, and the thickness of film B accounting for 15% of the total sheet thickness.

[0745] (5) Preparation of polypropylene fabrics:

[0746] The preparation method was the same as that in step (5) of Example B14.

[0747] (6) Preparation of polypropylene composite material:

[0748] The preparation method was the same as that in step (6) of Example B14.

[0749] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0750] Example B19

[0751] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0752] (1) Preparation of polypropylene composition A:

[0753] The preparation method was the same as that in step (1) of Example B14.

[0754] (2) Preparation of polypropylene composition C:

[0755] The preparation method was the same as that in step (2) of Example B14.

[0756] (3) Preparation of polypropylene composition B:

[0757] The preparation method was the same as that in step (3) of Example B14.

[0758] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0759] The preparation method was the same as that in step (4) of Example B14.

[0760] (5) Preparation of polypropylene fabrics:

[0761] The main steps were the same as step (5) of Example B14. Oriented tapes were woven according to the designed fabric structure using a commercial weaving machine to produce polypropylene satin weave fabrics.

[0762] (6) Preparation of polypropylene composite material:

[0763] The preparation method was the same as that in step (6) of Example B14.

[0764] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0765] Example B20

[0766] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0767] (1) Preparation of polypropylene composition A:

[0768] The preparation method was the same as that in step (1) of Example B14.

[0769] (2) Preparation of polypropylene composition C:

[0770] The preparation method was the same as that in step (2) of Example B14.

[0771] (3) Preparation of polypropylene composition B:

[0772] The preparation method was the same as that in step (3) of Example B14.

[0773] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0774] The basic preparation method was the same as that in step (4) of Example B14. In this case, the sheet stretch ratio was 10.

[0775] (5) Preparation of polypropylene fabrics:

[0776] The preparation method was the same as that in step (5) of Example B14.

[0777] (6) Preparation of polypropylene composite material:

[0778] The preparation method was the same as that in step (6) of Example B14.

[0779] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0780] Example B21

[0781] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0782] (1) Preparation of polypropylene composition A:

[0783] The preparation method was the same as that in step (1) of Example B14.

[0784] (2) Preparation of polypropylene composition C:

[0785] The preparation method was the same as that in step (2) of Example B14.

[0786] (3) Preparation of polypropylene composition B:

[0787] The preparation method was the same as that in step (3) of Example B14.

[0788] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0789] The preparation method was the same as that in step (4) of Example B14.

[0790] (5) Preparation of polypropylene fabrics:

[0791] The preparation method was the same as that in step (5) of Example B14.

[0792] (6) Preparation of polypropylene composite material:

[0793] The basic preparation method was the same as that in step (6) of Example B14. In this case, the polypropylene fabrics were laid at an angle of 45 degrees to each other along their respective warp directions.

[0794] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0795] Example B22

[0796] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0797] (1) Preparation of polypropylene composition A:

[0798] The preparation method was the same as that in step (1) of Example B14.

[0799] (2) Preparation of polypropylene composition C:

[0800] The preparation method was the same as that in step (2) of Example B14.

[0801] (3) Preparation of polypropylene composition B:

[0802] The preparation method was the same as that in step (3) of Example B14.

[0803] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0804] The preparation method was the same as that in step (4) of Example B14.

[0805] (5) Preparation of polypropylene fabrics:

[0806] The preparation method was the same as that in step (5) of Example B14.

[0807] (6) Preparation of polypropylene composite material:

[0808] The basic preparation method was the same as that in step (6) of Example B14. In this case, the polypropylene fabrics were laid at an angle of 0 degrees relative to each other along their respective warp directions.

[0809] The thickness of the prepared PP composite material was similar to Example B14.

[0810] Example B23

[0811] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0812] (1) Preparation of polypropylene composition A:

[0813] The preparation method was the same as that in step (1) of Example B14.

[0814] (2) Preparation of polypropylene composition C:

[0815] The preparation method was the same as that in step (2) of Example B14.

[0816] (3) Preparation of polypropylene composition B:

[0817] The preparation method was the same as that in step (3) of Example B14.

[0818] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0819] The preparation method was the same as that in step (4) of Example B14.

[0820] (5) Preparation of polypropylene fabrics:

[0821] The preparation method was the same as that in step (5) of Example B14.

[0822] (6) Preparation of polypropylene composite material:

[0823] The main preparation method was the same as that in step (6) of Example B14. The sheet of stacked polypropylene composite material contained 2 layers of polypropylene fabrics. The hot pressing conditions used were: temperature of 145°C, hot pressing pressure of 2 MPa, preheating time of 150 s, hot pressing time of 60 s, and cooling time of 300 s. The thickness of the prepared polypropylene composite material was 136 μm.

[0824] Example B24

[0825] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0826] (1) Preparation of polypropylene composition A:

[0827] The preparation method was the same as that in step (1) of Example B14.

[0828] (2) Preparation of polypropylene composition C:

[0829] The preparation method was the same as that in step (2) of Example B14.

[0830] (3) Preparation of polypropylene composition B:

[0831] The preparation method was the same as that in step (3) of Example B14.

[0832] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0833] The preparation method was the same as that in step (4) of Example B14.

[0834] (5) Preparation of polypropylene fabrics:

[0835] The preparation method was the same as that in step (5) of Example B14.

[0836] (6) Preparation of polypropylene composite material:

[0837] The main preparation method was the same as that in step (6) of Example B14. The sheet of stacked polypropylene composite material contained 100 layers of polypropylene fabrics. The hot pressing conditions used were: temperature of 159°C, hot pressing pressure of 10 MPa, preheating time of 420 s, hot pressing time of 300 s, and cooling time of 700 s. The thickness of the prepared polypropylene composite material was 7.45 mm.

[0838] Example B25

[0839] This example is used to illustrate the preparation of a polypropylene composition, five-layer coextruded polypropylene composite sheets, polypropylene fabrics and polypropylene composite materials proposed in the present invention.

[0840] (1) Preparation of polypropylene composition A:

[0841] The preparation method was the same as that in step (1) of Example B14.

[0842] (2) Preparation of polypropylene composition C:

[0843] The preparation method was the same as that in step (2) of Example B14.

[0844] (3) Preparation of polypropylene composition B:

[0845] The preparation method was the same as that in step (3) of Example B14.

[0846] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0847] The preparation method was the same as that in step (4) of Example B14.

[0848] (5) Preparation of polypropylene fabrics:

[0849] The preparation method was the same as that in step (5) of Example B14.

[0850] (6) Preparation of polypropylene composite material:

[0851] The main preparation method was the same as that in step (6) of Example B14. The hot pressing conditions used were: temperature of 155°C, hot pressing pressure of 8 MPa, preheating time of 300 s, hot pressing time of 300 s, and cooling time of 700 s. The thickness of the prepared polypropylene composite material was 1.61 mm.

[0852] Example B26

[0853] This example is used to illustrate the preparation of a polypropylene composition, a five-layer coextruded polypropylene sheet, a polypropylene fabric, and polypropylene composite materials proposed in the present invention.

[0854] (1) Preparation of polypropylene composition A:

[0855] The preparation method was the same as that in step (1) of Example B14.

[0856] (2) Preparation of polypropylene composition C:

[0857] The preparation method was the same as that in step (2) of Example B14.

[0858] (3) Preparation of polypropylene composition B:

[0859] The preparation method was the same as that in step (3) of Example B14.

[0860] (4) Preparation of five-layer coextruded polypropylene composite sheets:

[0861] The preparation method was the same as that in step (4) of Example B14.

[0862] (5) Preparation of polypropylene composite material:

[0863] The basic preparation method was the same as that in step (6) of Example B14. The exception was that instead of preparing polypropylene fabrics, the five-layer coextruded polypropylene sheets obtained in the above-described step (4) (replacing the polypropylene fabrics in Example B14) were subjected to sequential laying and hot pressing.

[0864] The thickness of the prepared PP composite material was similar to Example B14.

[0865] Example B27

[0866] Five-layer coextruded polypropylene sheets were prepared according to the methods of Example B14, except that the material of component A was selected as follows: component a was a polypropylene homopolymer prepared by SINOPEC with a melting point of 155°C, a melt flow rate of 14.3 g / 10 min, and a stereoregularity of 96%.

[0867] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0868] Example B28

[0869] Five-layer coextruded polypropylene sheets were prepared according to the methods of Example B14, except that the material of component B was selected as follows: component x was a random copolymer of polypropylene prepared by SINOPEC, which is an ethylene-propylene-butene terpolymer with a molecular weight distribution (Mw / Mn) of 10.5, a melting point of 130°C, and a melt flow rate of 9.2 g / 10 min;

[0870] The thickness of the prepared PP composite material was similar to Example B14.

[0871] Comparative Example B1

[0872] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that one polypropylene composition A was extruded and cast to prepare a single-layer film with a thickness of 80 μm. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0873] The thickness of the prepared PP composite material was similar to Example B1.

[0874] Comparative Example B2

[0875] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that one polypropylene composition B was extruded and cast to prepare a single-layer film with a thickness of 80 μm. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0876] The thickness of the prepared PP composite material was similar to Example B1.

[0877] Comparison Example B3

[0878] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that the polypropylene composition A contained only component b. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0879] The thickness of the prepared PP composite material was similar to Example B1.

[0880] Comparative Example B4

[0881] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that the polypropylene composition B contained only the y component. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0882] The thickness of the prepared PP composite material was similar to Example B1.

[0883] Comparative Example B5

[0884] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that the thickness of film layer A was 95% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example B1.

[0885] The thickness of the prepared PP composite material was similar to Example B1.

[0886] Comparison Example B6

[0887] Three-layer coextruded polypropylene sheets were prepared according to the methods of Example B1, except that the thickness of film layer A was 50% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example B1.

[0888] The thickness of the prepared PP composite material was similar to Example B1.

[0889] Comparison Example B7

[0890] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that one polypropylene composition A was extruded and cast to prepare a single-layer film with a thickness of 80 μm. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0891] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0892] Comparison Example B8

[0893] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that one polypropylene composition C was extruded and cast to prepare a single-layer film with a thickness of 80 μm. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0894] The thickness of the prepared PP composite material was similar to Example B14.

[0895] Comparison Example B9

[0896] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that one polypropylene composition B was extruded and cast to prepare a single-layer film with a thickness of 80 μm. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0897] The thickness of the prepared polypropylene composite material was similar to Example B14.

[0898] Comparison Example B10

[0899] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that the polypropylene composition A contained only component b. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0900] The thickness of the prepared PP composite material was similar to Example B14.

[0901] Comparison Example B11

[0902] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that the polypropylene composition B contained only the y component. Polypropylene fabrics and a polypropylene composite material were prepared according to the methods of Example B1.

[0903] The thickness of the prepared PP composite material was similar to Example B14.

[0904] Comparison Example B12

[0905] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that the thickness of film A was 95% of the total sheet thickness, the thickness of film C was 2.5% of the total sheet thickness, and the thickness of film B was 2.5% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example B1.

[0906] The thickness of the prepared PP composite material was similar to Example B14.

[0907] Comparison Example B13

[0908] Five-layer coextruded polypropylene composite sheets were prepared according to the methods of Example B14, except that the thickness of film A was 50% of the total sheet thickness, the thickness of film C was 25% of the total sheet thickness, and the thickness of film B was 25% of the total sheet thickness. Polypropylene fabrics and polypropylene composite materials were prepared according to the methods of Example B1.

[0909] The thickness of the prepared PP composite material was similar to Example B14.

[0910] Experimental Examples

[0911] The polypropylene composite materials obtained in the above Examples and Comparative Examples were tested according to the following methods, and the results are shown in Tables 2 and 3:

[0912] (1) Tensile strength: determined in accordance with the method specified in GB / T1040.1-2018;

[0913] (2) Tear strength of intermediate layer: determined in accordance with the method specified in GB / T2358-98.

[0914] (3) Drop impact strength: determined according to the method described in GB / T14153-1993. All the thicknesses of the polypropylene composite materials obtained in Examples B1-9 and Comparative Examples B1-6 were close to approximately 1.6 mm, and were within the range of 1.6 mm ±1 mm. All the thicknesses of the polypropylene composite materials obtained in Examples B14-22, B26 and Comparative Examples B7-13 were close to approximately 1.8 mm, and were within the range of 1.8 mm ±1 mm.

[0915] Table 2

[0916] № Tensile strength (MPa) Drop impact strength (J) Tear strength (N / mm) Example B1 187 246,81 1,23 Example B2 176 242,16 1,34 Example B3 194 240,83 1,21 Example B4 201 249,14 1,07 Example B5 164 257,68 1,45 Example B6 171 273,98 1,12 Example B7 257 228,96 1,14 Example B8 176 243,71 1,24 Example B9 154 228,96 1,22 Example B10 205 20,76 1,28 Example B11 158 999,31 1,21 Example B12 171 244,49 1,36 Example B13 195 241,38 1,38 Comparative example B1 198 153,68 0,56 Comparative example B2 89 241,38 2,47 Comparative example B3 136 222,75 1,28 Comparative example B4 178 231,29 0,87 Comparative example B5 179 202,57 0,63 Comparative example B6 104 227,41 1,98

[0917] From the results of the examples in Table 3, it can be seen that the polypropylene composite materials prepared according to the present invention have good tensile strength and impact resistance properties, and at the same time also have good tear strength of the intermediate layer at a lower hot pressing temperature. The polypropylene composite material sheets described in the present invention have a tensile strength in the machine direction (MD) of ≥150 MPa, a tear strength of the intermediate layer of ≥1 N / mm; and when the polypropylene composite materials are obtained by hot pressing and fusing 24 layers of polypropylene fabrics and have a thickness of approximately 1.6 mm, they have a drop impact strength of ≥228 J.

[0918] From the preferred examples B1-3, it can be seen that the polypropylene composite materials prepared according to the present invention have a tensile strength in the machine direction (MD) of ≥170 MPa, a tear strength of the intermediate layer of ≥1.2 N / mm; and when the polypropylene composite materials are obtained by hot pressing and fusing 24 layers of polypropylene fabrics and have a thickness of approximately 1.6 mm, they have a drop impact strength of ≥240 J.

[0919] From Comparative Examples B1-6, it can be seen that the use of only a single-layer sheet structure or the use of a proportion of an intermediate layer outside the scope of the examples according to the present invention result in a deterioration in the performance of multilayer polypropylene sheets or fabrics, resulting in a significant decrease in the tensile strength, impact properties or tear strength of the intermediate layer of the resulting polypropylene composite materials.

[0920] Table 3

[0921] Machine direction tensile strength Drop impact strength Tear strength of the intermediate layer (MPa) (J) (N / mm) Example B14 178 256,91 1,31 Example B15 171 280,97 1,36 Example B16 185 251,59 1,30 Example B17 196 264,67 1,13 Example B18 161 273,98 1,51 Example B19 168 296,49 1,16 Example B20 245 244,49 1,19 Example B21 171 257,68 1,29 Example B22 151 246,81 1,28 Example B23 198 21,21 1,31 Example B24 151 1009,12 1,25 Example B25 165 249,14 1,39 Example B26 181 245,31 1,42 Example B27 148 242,68 1,22 Example B28 154 223,76 1,29 Comparative example B7 198 166,09 0,56 Comparative example B8 76 233,62 2,98 Comparative example B9 89 249,14 2,47 Comparative example B10 131 242,16 1,29 Comparative example B11 172 244,49 0,95 Comparative example B12 171 228,19 0,71 Comparative example B13 98 247,59 2,09

[0922] From the results of the examples in Table 3, it can be seen that the polypropylene composite materials prepared according to the present invention have good tensile strength and impact resistance properties, and at the same time also have good tear strength of the intermediate layer at a lower hot pressing temperature. When the polypropylene composite material sheets have a BCACB structure, the polypropylene composite materials described in the present invention have a tensile strength in the machine direction (MD) of ≥150 MPa and a tear strength of the intermediate layer of ≥1.1 N / mm; and when the polypropylene composite materials are obtained by hot pressing and fusing 24 layers of polypropylene fabrics and have a thickness of approximately 1.8 mm, they have a drop impact strength of ≥240 J.

[0923] From the preferred examples B14-16, it can be seen that the polypropylene composite materials prepared according to the present invention have a tensile strength in the machine direction (MD) of ≥170 MPa and a tear strength of the intermediate layer of ≥1.3 N / mm; and when the polypropylene composite materials are obtained by hot pressing and fusing 24 layers of polypropylene fabrics and have a thickness of approximately 1.8 mm, they have a falling impact strength of ≥250 J. From the comparative examples B7-13, it can be seen that the use of only a single-layer film structure or the use of a film layer ratio outside the scope of the examples according to the present invention lead to a deterioration in the characteristics of multilayer polypropylene sheets or fabrics, which leads to a significant decrease in the tensile strength, impact properties or tear strength of the intermediate layer of the obtained polypropylene composite materials.

[0924] Various examples of the present invention have been described above. The foregoing description is exemplary and not exhaustive, and is not limited to the disclosed examples. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described examples.

[0925] Neither the endpoints nor any values ​​of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values ​​are intended to include values ​​approximating these ranges or values. For numerical ranges, one or more new numerical ranges may be obtained by combining the endpoints of each range with each other, the endpoint of each range with the value of an individual point, and the values ​​of individual points with each other, and these ranges of values ​​shall be considered as disclosed herein.

Claims

1. A polypropylene composite material comprising sequentially stacked groups of polypropylene layers; each group of polypropylene layers comprises at least one of the same or different polypropylene layers and each polypropylene layer comprises a base layer A i and outer layers B i and B' i , located on both sides of the main layer A i , with structure B i A i B' i ; the structure of the polypropylene composite material looks like group n, …, group i, …, group 2, group 1, group 2, …, group i, …, group n, in the direction from bottom to top, the total number of stacked groups of polypropylene layers is 2n-1; i and n are integers not less than 2 and i ≤ n; where the main layer is A i in the polypropylene layer contains a polypropylene composition A i , outer layer B i is the same as or different from the outer layer B' i, outer layer B i contains polypropylene composition B i and the outer layer B' i contains polypropylene composition B' i , melting point of polypropylene composition A i greater than the melting point of polypropylene composition B i and polypropylene composition B' i ; and the average value of the melting temperatures of all outer layers in group i is greater than the average value of the melting temperatures of all outer layers in group i-1.

2. A polypropylene composite material according to paragraph 1, characterized in that: each of the difference between the melting temperature of the polypropylene composition A i and the melting temperature of the polypropylene composition B i and the difference between the melting temperature of the polypropylene composition A i and the melting temperature of the polypropylene composition B' igreater than or equal to 5°C, preferably greater than or equal to 10°C, more preferably greater than or equal to 20°C; and / or the differences between the average value of melting temperatures of all outer layers in group i and the average value of melting temperatures of all outer layers in group i-1, whether they are the same or different, are each 1-40°C, preferably 1-10°C and more preferably 1-5°C.

3. A polypropylene composite material according to paragraph 1 or 2, characterized in that: 2 ≤ n ≤ 100, preferably 2 ≤ n ≤ 50; and / or each of the groups of layers of the polypropylene sheet, independently of each other, contains 1-10, preferably 1-5 identical or different polypropylene layers.

4. A polypropylene composite material according to any one of paragraphs 1-3, characterized in that: the polypropylene layer also contains intermediate layers C i and C' i and the structure of the polypropylene layer is B i C iA i C' i B' i ; intermediate layer C i is the same or different from the intermediate layer C' i , intermediate layer C i contains polypropylene composition C i , and the intermediate layer C' i contains polypropylene composition C' i ; And melting point of polypropylene composition A i greater than the melting point of the polypropylene composition C i and polypropylene composition C' i .

5. A polypropylene composite material according to any one of paragraphs 1-4, characterized in that thickness of the base layer A i in each polypropylene layer is 51-89% of the total thickness of the polypropylene layer, preferably 71-89% and more preferably 71-80%.

6. A polypropylene composite material according to any one of paragraphs 1-5, characterized in that: polypropylene composition A icontains one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or each of the polypropylene compositions B i and B' i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer and a polypropylene block copolymer; preferably a polypropylene composition B i and / or polypropylene composition B' i additionally contains an amplifier y i thermal bonding.

7. A polypropylene composite material according to paragraph 4, characterized in that: each of the polypropylene compositions C i and C' i contains one or more of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; preferably a polypropylene composition C i and / or polypropylene composition C' i also contains the z amplifier i thermal bonding.

8. A polypropylene composite material according to any one of paragraphs 1-7, characterized in that: polypropylene composition A i contains polypropylene homopolymer a i and polypropylene block copolymer b i ; preferably polypropylene composition A i contains 50-99% by weight of polypropylene homopolymer a i , 1-50 wt.% polypropylene block copolymer b i ; more preferably a polypropylene composition A i contains 70-90% by weight of polypropylene homopolymer a i , 10-30 wt.% polypropylene block copolymer b i by total weight of polypropylene composition A i ; and / or each of the polypropylene compositions B i and B' i contains a random copolymer of polypropylene x i and amplifier y i thermal bonding; preferably each of the polypropylene compositions B i and B' icontains 70-99% by weight of random copolymer of polypropylene x i and 1-30 wt.% of the enhancer y i thermal bonding; more preferably 80-90 wt.% random copolymer of polypropylene x i and 10-20 wt.% of the enhancer y i thermal bonding by total weight of each polypropylene composition B i or B' i .

9. A polypropylene composite material according to paragraph 4, characterized in that: each of the polypropylene compositions C i and C' i contains a random copolymer of polypropylene β i and polypropylene homopolymer γ i , as well as the z amplifier i thermal bonding; preferably each of the polypropylene compositions C i and C' i contains 30-60 wt.% of the enhancer z i thermal bonding, 35-55 wt.% random copolymer of polypropylene β i and 5-15 wt.% of polypropylene homopolymer γ i; more preferably 35-55 wt.% of the enhancer z i thermal bonding, 40-55 wt.% random copolymer of polypropylene β i and 5-10 wt.% of polypropylene homopolymer γ i by the total weight of each polypropylene composition C i or C' i .

10. A polypropylene composite material according to paragraph 8, characterized in that polypropylene homopolymer a i has: melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or stereoregularity (mm) not less than 96%.

11. A polypropylene composite material according to paragraph 9, characterized in that: polypropylene homopolymer γ i has: melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or stereoregularity (mm) not less than 96%; preferably, polypropylene composition A i contains polypropylene homopolymer a i and polypropylene block copolymer b i ; And polypropylene homopolymer a i and polypropylene homopolymer γ i have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or the difference in melt flow rates at 230°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and / or the difference in stereoregularities (mm) is less than 3%, preferably less than 2% and more preferably less than 1%; even more preferably a polypropylene homopolymer a i and polypropylene homopolymer γi are the same.

12. A polypropylene composite material according to paragraph 8, characterized in that: polypropylene block copolymer b i has a melting point of 150-170°C; and / or a monomer copolymerizable with propylene in a polypropylene b block copolymer i , is ethylene or butene, preferably butene; and / or polypropylene block copolymer b i has a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or polypropylene block copolymer b i has an Izod impact strength of at least 20 kJ / m 2 .

13. A polypropylene composite material according to paragraph 8, characterized in that: random copolymer of polypropylene x i has: melting point of 110-150°C, preferably 120-140°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 3-18 g / 10 min; and / or molecular weight distribution Mw / Mn 5-12, preferably 7-10; and / or random copolymer of polypropylene x i is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer.

14. A polypropylene composite material according to paragraph 9, characterized in that: random copolymer of polypropylene β i has: melting point of 110-150°C, preferably 120-140°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 3-18 g / 10 min; and / or molecular weight distribution Mw / Mn 5-12, preferably 7-10; and / or random copolymer of polypropylene β iis a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer; preferably each of the polypropylene compositions B i and B' i contains a random copolymer of polypropylene x i and amplifier y i thermal bonding; and random copolymer of polypropylene x i and random copolymer of polypropylene β i have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or the difference in melt flow rates at 230°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and / or the difference in molecular weight distributions is less than 3, preferably less than 2, and more preferably less than 1; even more preferably a random copolymer of polypropylene x iand random copolymer of polypropylene β i are the same.

15. A polypropylene composite material according to paragraph 8, characterized in that: amplifier y i thermal bonding has: melting point or laminar flow temperature of 70-110°C; and / or a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 1-18 g / 10 min; and / or amplifier y i thermal bonding is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; preferably a polyolefin elastomer and / or a coumarone-indene resin.

16. A polypropylene composite material according to paragraph 9, characterized in that: amplifier z i thermal bonding has: melting point or laminar flow temperature of 70-110°C; and / or a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 1-18 g / 10 min; and / or amplifier z i thermal bonding is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; preferably a polyolefin elastomer and / or a coumarone-indene resin; preferably each of the polypropylene compositions B i and B' i contains a random copolymer of polypropylene x i and amplifier y i thermal bonding; and amplifier y i thermal bonding and enhancer z i thermal bonding have: the difference in melting temperatures or laminar flow temperatures is less than 10°C, preferably less than 5°C and more preferably less than 3°C; and / or the difference in melt flow rates at 190°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and even more preferable is the y amplifier i thermal bonding and enhancer z i thermal bonding are the same.

17. A polypropylene composite material according to paragraph 15 or 16, characterized in that: the polyolefin elastomer is an elastomer of ethylene copolymerized with propylene and / or an α-olefin, the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or The coumaroneindene resin is a hydrogenated C5 and / or C9 coumaroneindene resin with a softening point of 100-150°C; and is preferably a cyclopentadiene type resin.

18. A polypropylene composite material according to paragraph 6, characterized in that: polypropylene composition A i also contains a β-nucleating agent; preferably The β-nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, two-component complexes of Group IIA, aromatic diamides, rare earth metal compounds, and cyclic dicarboxylate nucleating agents; and / or content of β-nucleating agent in polypropylene composition A i is 0.01-0.5 m. parts per 100 m. parts of the total amount of polypropylene composition A i .

19. A polypropylene composite material according to any one of paragraphs 1-18, characterized in that: the polypropylene layer is a polypropylene sheet and / or a polypropylene fabric; the polypropylene layer is a polypropylene sheet or a polypropylene fabric; more preferably polypropylene sheet is prepared by coextruding components containing polypropylene composition A i , polypropylene composition B i , polypropylene composition B' i , an optional polypropylene composition C i and an optional polypropylene composition C' i ; and / or The polypropylene fabric is prepared in the following way: first by coextruding the components containing the polypropylene composition A i , polypropylene composition B i , polypropylene composition B' i , an optional polypropylene composition C i and an optional polypropylene composition C' ito obtain a polypropylene sheet, and then weaving the polypropylene sheet to obtain a polypropylene fabric; wherein preferably the polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

20. A polypropylene composite material according to paragraph 19, characterized in that Various sheets of polypropylene layer are bonded by hot pressing.

21. A method for producing a polypropylene composite material according to any one of claims 1-20, comprising the steps of: sequentially laying out 2n-1 groups of polypropylene layers in the sequence group n, ..., group i, ..., group 2, group 1, group 2, ..., group i, ..., group n, and then performing hot pressing and fusing.

22. The production method according to paragraph 21, characterized in that it contains the following stages: (1) polypropylene composition A i , polypropylene composition B i , polypropylene composition B'i , optional polypropylene composition C i and an optional polypropylene composition C' i coextruded, cast or calendered and stretched according to structure B i A i B' i or structure B i C i A i C' i B' i in order to obtain a polypropylene sheet; (2) Optionally, the polypropylene sheet is divided and cut, and then woven to obtain the B-structure polypropylene fabric i A i B' i or B i C i A i C' i B' i ; (3) polypropylene sheets and / or polypropylene fabrics are successively stacked, hot pressed and fused, and then cooled and molded to form a polypropylene composite material.

23. The method of production according to paragraph 22, characterized in that: preparation of polypropylene composition A i in step (1) comprises melt-blending components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or preparation of polypropylene composition B i and polypropylene composition B' i in step (1) comprises melt-blending components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or preparation of polypropylene composition C i and polypropylene composition C' i in step (1) comprises melt-blending components comprising at least one of a polypropylene homopolymer, a polypropylene random copolymer, and a polypropylene block copolymer; and / or the coextrusion and casting temperatures in step (1) are independently selected from the range of 190-240°C; and / or the calender temperature at stage (1) is 50-70°C; and / or the stretching temperature in step (1) is 90-165°C, preferably 90-140°C, and more preferably 90-119°C; and / or The degree of stretching at stage (1) is 1-15.

24. The production method according to paragraph 22, characterized in that at stage (3): the hot pressing conditions comprise: a hot pressing temperature of 115-170°C, preferably 115-159°C, more preferably 140-159°C; a hot pressing pressure of 2-10 MPa, a heating time of 5-600 s and a hot pressing time of 1-600 s, preferably 10-500 s; and / or cooling and forming pressure of 2-8 MPa and cooling time of 30-700 s; and / or the adjacent polypropylene fabrics being stacked are positioned at an angle of 0-90 degrees relative to each other along their respective warp directions; and / or The adjacent polypropylene sheets are stacked at an angle of 0-90 degrees relative to each other along their respective machine directions.

25. A continuous hot pressing system for forming a polypropylene composite material according to any one of claims 1 to 20, comprising a preheater, a track-type continuous flat hot press, a track-type continuous flat cold press, a sheet cutting machine and a sheet stacking machine arranged in series.

26. The continuous hot pressing molding system according to claim 25, characterized in that The crawler-type continuous flat hot press consists of a heating unit, an independent heating and pressing unit, an air cooling unit and a lifting mechanism.

27. The use of a polypropylene composite material according to any of paragraphs 1-20 for the production of consumer goods selected from luggage, footwear, audio equipment.

28. A polypropylene sheet comprising a layer A and layers B and B' located on both sides of layer A, with a BAB' structure; wherein layer A comprises polypropylene composition A, layer B is the same as or different from layer B', layer B comprises polypropylene composition B, and layer B' comprises polypropylene composition B', and the melting point of polypropylene composition A is higher than the melting point of polypropylene composition B and polypropylene composition B'; wherein the polypropylene composition A comprises a polypropylene homopolymer a and a polypropylene block copolymer b; and each of the polypropylene composition B and the polypropylene composition B' comprises a random copolymer of polypropylene x and a thermal bonding enhancer y.

29. A polypropylene sheet according to clause 28, characterized in that the polypropylene sheet is used as a polypropylene layer in the polypropylene composite material according to paragraph 1.

30. A polypropylene sheet according to paragraph 28, characterized in that: the polypropylene sheet further comprises layers C, C' with a BCAC'B' structure; layer C is the same as or different from layer C', layer C comprises a polypropylene composition C, and layer C' comprises a polypropylene composition C'; the melting point of the polypropylene composition A is higher than the melting point of the polypropylene composition C and the polypropylene composition C'; wherein each of the polypropylene compositions C and C' contains a random copolymer of polypropylene β and a homopolymer of polypropylene γ, as well as a binding enhancer z.

31. A polypropylene sheet according to paragraph 28, characterized in that: the polypropylene composition A comprises 50-99 wt.% of the polypropylene homopolymer a and 1-50 wt.% of the polypropylene block copolymer b; more preferably, the polypropylene composition A comprises 70-90 wt.% of the polypropylene homopolymer a and 10-30 wt.% of the polypropylene block copolymer b based on the total weight of the polypropylene composition A; and / or each of the polypropylene compositions B and B' contains 70-99 wt.% of a random copolymer of polypropylene x and 1-30 wt.% of a thermal bonding enhancer y; preferably 80-90 wt.% of a random copolymer of polypropylene x and 10-20 wt.% of a thermal bonding enhancer y based on the total weight of each polypropylene composition B or B'.

32. A polypropylene sheet according to claim 28, characterized in that the thickness of layer A is 51-89% of the total thickness of the polypropylene sheet, preferably 71-89% and more preferably 71-80%.

33. A polypropylene sheet according to item 30, characterized in that each of the polypropylene compositions C and C' contains 30-60 wt.% of thermal bonding enhancer z, 35-55 wt.% of random copolymer of polypropylene β and 5-15 wt.% of homopolymer of polypropylene γ; preferably 35-55 wt.% of thermal bonding enhancer z, 40-55 wt.% of random copolymer of polypropylene β and 5-10 wt.% of homopolymer of polypropylene γ based on the total weight of each polypropylene composition C or C'.

34. A polypropylene sheet according to paragraph 30, characterized in that: the thickness of layer A is 51-89% of the total thickness, preferably 71-89%; the thickness of layers C, C' is 6-20% of the total thickness, preferably 6-15%; and the thickness of layers B, B' is 5-30% of the total thickness, preferably 5-15% of the total thickness of each polypropylene sheet.

35. A polypropylene sheet according to paragraph 28, characterized in that polypropylene homopolymer a has: melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or stereoregularity (mm) not less than 96%.

36. A polypropylene sheet according to paragraph 30, characterized in that: polypropylene homopolymer γ has: melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or stereoregularity (mm) not less than 96%; preferably the polypropylene homopolymer a and the polypropylene homopolymer γ have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or the difference in melt flow rates at 230°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and / or the difference in stereoregularities (mm) is less than 3%, preferably less than 2% and more preferably less than 1%; even more preferably, the polypropylene homopolymer a and the polypropylene homopolymer γ are the same.

37. A polypropylene sheet according to paragraph 28, characterized in that: the polypropylene block copolymer b has a melting point of 150-170°C; and / or the monomer copolymerizable with propylene in the polypropylene block copolymer b is ethylene or butene, preferably butene; and / or the polypropylene block copolymer b has a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 2.5-18 g / 10 min; and / or The polypropylene block copolymer b has an Izod impact strength of at least 20 kJ / m2 .

38. A polypropylene sheet according to clause 28, characterized in that: random copolymer of polypropylene x has: melting point of 110-150°C, preferably 120-140°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 3-18 g / 10 min; and / or molecular weight distribution Mw / Mn 5-12, preferably 7-10; and / or the random copolymer of polypropylene x is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer.

39. A polypropylene sheet according to paragraph 30, characterized in that: random copolymer of polypropylene β has: melting point of 110-150°C, preferably 120-140°C; and / or a melt flow rate at 230°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 3-18 g / 10 min; and / or molecular weight distribution Mw / Mn 5-12, preferably 7-10; and / or the polypropylene β random copolymer is a copolymer of propylene with ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene bipolymer; preferably the random copolymer of polypropylene x and the random copolymer of polypropylene β have: a melting point difference of less than 10°C, preferably less than 5°C, more preferably less than 3°C; and / or the difference in melt flow rates at 230°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and / or the difference in molecular weight distributions is less than 3, preferably less than 2, and more preferably less than 1; even more preferably, the random copolymer of polypropylene x and the random copolymer of polypropylene β are the same.

40. A polypropylene sheet according to paragraph 28, characterized in that: Thermal bonding enhancer has: melting point or laminar flow temperature of 70-110°C; and / or a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 1-18 g / 10 min; and / or the thermal bonding enhancer is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; preferably a polyolefin elastomer and / or a coumarone-indene resin.

41. A polypropylene sheet according to paragraph 30, characterized in that: Thermal bonding enhancer z has: melting point or laminar flow temperature of 70-110°C; and / or a melt flow rate at 190°C and a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min and more preferably 1-18 g / 10 min; and / or the thermal bonding enhancer z is selected from one or more of a polyolefin elastomer, an ethylene-propylene-diene terpolymer rubber, SEBS, SBS, EVA and a coumarone-indene resin; preferably a polyolefin elastomer and / or a coumarone-indene resin; preferably the thermal bonding enhancer y and the thermal bonding enhancer z have: the difference in melting temperatures or laminar flow temperatures is less than 10°C, preferably less than 5°C and more preferably less than 3°C; and / or the difference in melt flow rates at 190°C and a load of 2.16 kg is less than 10 g / 10 min, preferably less than 5 g / 10 min and more preferably less than 3 g / 10 min; and even more preferably, the thermal bonding enhancer y and the thermal bonding enhancer z are the same.

42. A polypropylene sheet according to clause 40 or 41, characterized in that: the polyolefin elastomer is an elastomer of ethylene copolymerized with propylene and / or an α-olefin, the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or The coumaroneindene resin is a hydrogenated C5 and / or C9 coumaroneindene resin with a softening point of 100-150°C; and is preferably a cyclopentadiene type resin.

43. A polypropylene sheet according to any of paragraphs 28-42, characterized in that: polypropylene composition A also contains a β-nucleating agent; preferably The β-nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, two-component complexes of Group IIA, aromatic diamides, rare earth metal compounds, and cyclic dicarboxylate nucleating agents; and / or the content of β-nucleating agent in polypropylene composition A is 0.01-0.5 parts per 100 parts per 100 parts of the total amount of polypropylene composition A.

44. A polypropylene sheet according to paragraph 28, characterized in that: the melting point of the polypropylene homopolymer a in the polypropylene composition A is greater than the melting point of the random copolymer of polypropylene x in the polypropylene compositions B, B', and preferably the difference between the corresponding melting points is greater than or equal to 10°C; and / or The structure of the polypropylene sheet BAB is obtained by coextruding components containing polypropylene composition A and polypropylene compositions B, B'.

45. A polypropylene sheet according to paragraph 30, characterized in that: preferably, the melting point of the polypropylene homopolymer a in the polypropylene composition A is greater than the melting point of the random copolymer of polypropylene x in the polypropylene compositions B, B' and the melting point of the random copolymer of polypropylene β in the polypropylene compositions C, C', and the difference between the corresponding melting points is greater than or equal to 10°C; and / or The structure of the BCAC'B' polypropylene sheet is obtained by coextruding components containing polypropylene composition A, polypropylene compositions B, B' and polypropylene compositions C, C'.

46. ​​A method for producing a polypropylene sheet according to any one of claims 28 to 45, comprising: coextruding, casting or calendering a polypropylene composition A, a polypropylene composition B, a polypropylene composition B', an optional polypropylene composition C and an optional polypropylene composition C' according to the structure BAB' or BCAC'B' in order to obtain a polypropylene sheet.

47. A method for producing a polypropylene sheet according to paragraph 46, characterized in that the preparation of a polypropylene composition A comprises melt mixing components containing a polypropylene homopolymer a and a polypropylene block copolymer b; and / or the preparation of polypropylene compositions B, B' comprises melt mixing of components containing a random copolymer of polypropylene x and a thermal bonding enhancer y; and / or the preparation of polypropylene compositions C, C' comprises melt mixing of components containing a thermal bonding enhancer z, a random copolymer of polypropylene β and a homopolymer of polypropylene γ; and / or coextrusion and casting temperatures are independently selected from the range of 200-240°C; and / or the calender temperature is 50-70°C; and / or the stretching conditions comprise: a stretching temperature of 90-165°C, preferably 90-140°C, more preferably 90-119°C; and a stretching ratio of 1-15.

48. A polypropylene fabric which is a three-dimensional polypropylene fabric obtained by weaving a polypropylene sheet according to any one of paragraphs 28-45.

49. Polypropylene fabric according to paragraph 48, characterized in that: a polypropylene fabric obtained by dividing, cutting and weaving a polypropylene sheet; and / or which has a spatial structure of plain weave, twill weave and / or satin weave.

50. A polypropylene composite material obtained using layers of polypropylene sheet according to any of paragraphs 28-45 and / or polypropylene fabric according to paragraph 48 or 49 by means of hot pressing and fusing.

51. A polypropylene composite material according to paragraph 50, characterized in that: the polypropylene composite material is obtained by using layers of polypropylene sheets or polypropylene fabrics by hot pressing and fusing; and / or layers of polypropylene sheets are laid at an angle of 0-90 degrees relative to each other along their respective machine directions in a top-down direction; and / or layers of polypropylene fabrics are laid at an angle of 0-90 degrees relative to each other along their respective warp directions in a top-down direction; and / or the number of layers of polypropylene sheets or polypropylene fabrics is 2 or more, more preferably 2-200, and most preferably 4-100.

52. A method for producing a polypropylene composite material according to claim 50 or 51, comprising: laying, hot pressing and fusing polypropylene sheets or polypropylene fabrics, and then cooling and molding the polypropylene composite material.

53. The method of obtaining according to paragraph 52, characterized in that: the hot pressing and fusing temperature is 115-170°C, preferably 115-159°C, and more preferably 140-159°C; and / or the hot pressing and fusing pressure is 2-10 MPa; and / or the preheating time of hot pressing and fusing is 5-600 s, and the hot pressing time is 1-600 s, preferably 10-500 s; and / or the pressure for cooling and forming is 2-8 MPa, and the cooling and forming time is 30-700 s; and / or the number of layers of polypropylene sheets and / or polypropylene fabrics stacked in a stack is 2 or more, preferably 2-200 and more preferably 4-100; and / or adjacent layers of polypropylene fabrics are stacked at an angle of 0-90 degrees relative to each other along their respective warp directions; and / or The adjacent layers of polypropylene sheets placed in a stack are positioned at an angle of 0-90 degrees relative to each other along their respective machine directions.

54. The use of a polypropylene sheet according to any of paragraphs 28-45, for producing sports equipment.

55. Use of a polypropylene composite material according to any of paragraphs 1-20 for the production of a vehicle.

56. Use of a polypropylene composite material according to any of paragraphs 1-20 for producing sports equipment.

57. Use of a polypropylene sheet according to any of paragraphs 28-45 for the production of a vehicle.

58. The use of polypropylene sheet according to any of paragraphs 28-45 for the production of consumer goods selected from luggage, footwear, audio equipment.

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