Thermal insulation polypropylene sheet and its fabric, polypropylene composite material and its preparation and application

Abstract

This invention relates to the field of polypropylene materials, and discloses a heat-insulating polypropylene sheet and its fabric, a heat-insulating polypropylene composite material, and its preparation method and application. The heat-insulating polypropylene composite material includes a multi-layer heat-insulating polypropylene sheet, wherein the heat-insulating polypropylene sheet has a structure of BAB', including layer A and layers B and B' located on both sides of layer A; wherein layer A contains polypropylene composition A, and layers B and B' may be the same or different, each corresponding to polypropylene composition B and polypropylene composition B'; the contents of the corresponding heat-insulating agents c and z in polypropylene compositions A, B, and B' are not simultaneously 0; wherein the melting point of polypropylene composition A is greater than the melting points of polypropylene composition B and polypropylene composition B'. The heat-insulating polypropylene composite material of this invention is formed by hot pressing the heat-insulating polypropylene sheet. The introduced heat-insulating material can significantly reduce the thermal conductivity of polypropylene without significantly affecting the peel strength of the polypropylene composite material.

Description

Technical Field

[0001] This invention relates to the field of polypropylene materials, and more specifically, to a heat-insulating polypropylene sheet and its fabric, a heat-insulating polypropylene composite material, and its preparation and application. Background Technology

[0002] Polypropylene, as a general-purpose plastic, has advantages such as being lightweight, corrosion-resistant, and easy to process, and is widely used in daily life. In 2020, my country's apparent consumption of polypropylene exceeded 30 million tons, mainly used in the production of woven products, film products, injection molded products, and textile products, and is widely used in packaging, electronics, home appliances, automobiles, fibers, building pipes, and other fields.

[0003] Compared to metal-ceramic materials, polypropylene has better thermal insulation properties. In practical applications, its thermal insulation capabilities often need further improvement to make it an ideal substrate for lightweight thermal insulation products. Patent CN112321948A prepared a polypropylene thermal insulation material by melt blending fumed silica with polypropylene. Patent CN110305415A modified polypropylene by coating it with porous silica, large-particle titanium dioxide, high-compression hollow glass microspheres, talc, mica, etc. The resulting thermal insulation polypropylene composite material has an outdoor thermal insulation effect that is at least 10°C lower than that of ordinary materials.

[0004] Modifying polypropylene with conventional fillers can improve its thermal insulation properties to some extent, but it often leads to a significant decrease in interlayer peel strength when polypropylene is laminated in multiple layers. Therefore, developing a polypropylene composite material that combines thermal insulation properties with good interlayer peel strength is of significant practical importance. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical problem that current polypropylene composite materials cannot simultaneously achieve both thermal insulation performance and interlaminar peel strength, and to provide a thermally insulating polypropylene sheet and its fabric, a thermally insulating polypropylene composite material, and its preparation method and application. The thermally insulating polypropylene composite material of this invention is formed by hot-pressing thermally insulating polypropylene sheets. The introduced thermal insulation material can significantly reduce the thermal conductivity of polypropylene without significantly affecting the peel strength of the polypropylene composite material. Furthermore, this preparation method can reduce the hot-pressing operation time, while improving production efficiency and reducing production energy consumption. This thermally insulating polypropylene composite material not only has good thermal insulation performance, but also excellent mechanical properties and good interlaminar peel strength. It further solves the technical problem in the prior art that polypropylene composite materials are difficult to simultaneously possess a wide processing temperature range, strong mechanical properties, and high interlaminar peel strength.

[0006] In a first aspect, the object of the present invention is to provide a heat-insulating polypropylene sheet with a structure of BAB', comprising layer A and layers B and B' located on both sides of layer A; wherein layer A contains a polypropylene composition A, said polypropylene composition A comprising homopolymer polypropylene a, impact copolymer polypropylene b, and optionally a heat-insulating agent c.

[0007] Layer B may be the same as or different from layer B', and each contains a polypropylene composition B and a polypropylene composition B', wherein each of the polypropylene composition B and the polypropylene composition B' includes random copolymer polypropylene x, a thermal bonding reinforcing agent y, and an optional heat insulation agent z; and the contents of the corresponding heat insulation agents c and z in polypropylene composition A, polypropylene composition B, and polypropylene composition B' are not all 0 at the same time.

[0008] The melting point of polypropylene composition A is greater than that of polypropylene composition B and polypropylene composition B'.

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

[0010] According to the present invention, the melting point of the polypropylene composition A is greater than the melting points of the polypropylene compositions B and B'. Preferably, the difference between the melting points of polypropylene composition A and polypropylene composition B, and the difference between the melting points of polypropylene composition A and polypropylene composition B', are each greater than or equal to 5°C, more preferably greater than or equal to 10°C, and more preferably greater than or equal to 20°C.

[0011] Preferably, the melting point of homopolymer polypropylene a in polypropylene composition A is greater than the melting point of random copolymer polypropylene x in polypropylene composition B and polypropylene composition B', and preferably the temperature difference between the corresponding melting points is greater than or equal to 10°C.

[0012] The content range of each component in the polypropylene composition A is relatively wide. According to a preferred embodiment of the present invention, based on the total weight of the polypropylene composition A, the polypropylene composition A includes 50-99 wt% homopolymer polypropylene a, 1-40 wt% impact copolymer polypropylene b, and 0-10 wt% thermal insulation agent c; preferably, based on the total weight of the polypropylene composition A, the polypropylene composition A includes 50-98.5 wt% homopolymer polypropylene a, 1-40 wt% impact copolymer polypropylene b, and 0.5-10 wt% thermal insulation agent c; more preferably, the polypropylene composition A includes 65-94.5 wt% homopolymer polypropylene a, 5-30 wt% impact copolymer polypropylene b, and 0.5-5 wt% thermal insulation agent c.

[0013] The content range of each component in the polypropylene composition B and polypropylene composition B' is relatively wide. According to a preferred embodiment of the present invention, based on the total weight of each of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 60-99 wt% random copolymer polypropylene x, 1-20 wt% heat-bonding reinforcing agent y, and 0-20 wt% heat insulation agent z; preferably, based on the total weight of each of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 60-98 wt% random copolymer polypropylene x, 1-20 wt% heat-bonding reinforcing agent y, and 1-20 wt% heat insulation agent z; more preferably, each of the polypropylene composition B and the polypropylene composition B' comprises 75-94 wt% random copolymer polypropylene x, 5-15 wt% heat-bonding reinforcing agent y, and 1-10 wt% heat insulation agent z.

[0014] The thickness percentage of layer A has a wide range of selection. In a preferred embodiment of the present invention, based on the total thickness of the heat-insulating polypropylene sheet, the thickness of layer A accounts for 51%-89% of the total thickness, preferably 71%-89%, and more preferably 71%-80%. The thicknesses of layers B and B' on both sides of layer A can be the same or different, preferably the same.

[0015] The present invention does not limit the thickness of the heat-insulating polypropylene sheet, and it can be selected within a wide range according to its actual application field. Preferably, the thickness of the heat-insulating polypropylene sheet can be 10-1000μm, more preferably 30-500μm, and even more preferably 50-300μm.

[0016] According to the present invention, the thickness of layers A, B, and B' can be controlled by the extruder melt pump during the processing.

[0017] According to a preferred embodiment of the present invention, the homopolymer polypropylene a has:

[0018] Melting point is 150-170℃, preferably 160-170℃; and / or,

[0019] The melt flow rate at 230°C and 2.16 kg load is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, more preferably 2.5-18 g / 10 min; and / or,

[0020] The isotacticity (mm) is not less than 96%.

[0021] According to a preferred embodiment of the present invention, the impact-resistant copolymer polypropylene b has:

[0022] The impact-resistant copolymer polypropylene b has a melting point of 150-170℃: and / or,

[0023] The monomer for the copolymerization of the impact-resistant copolymer polypropylene b and propylene is ethylene or butene, preferably butene; and / or,

[0024] The impact-resistant copolymer polypropylene b has a melt flow rate of 0.5-50 g / 10 min at 230°C and 2.16 kg load, preferably 1-20 g / 10 min, and more preferably 2.5-18 g / 10 min; and / or, the cantilever beam impact strength of the impact-resistant copolymer polypropylene b is not less than 20 KJ / m. 2 (Tested at 23℃).

[0025] The heat insulation agent c has a wide range of material selection. In a preferred embodiment of the present invention, the heat insulation agent c is selected from at least one of silica aerogel, titanium dioxide aerogel, graphene aerogel, cellulose aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres, preferably at least one of silica aerogel, titanium dioxide aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres, and more preferably at least one of silica aerogel and maleic anhydride copolymer aerogel.

[0026] In a preferred embodiment of the present invention, the heat insulation agent c is spherical and / or near-spherical.

[0027] In a more preferred embodiment of the present invention, the particle size of the heat insulation agent c is 50-5000 nm, preferably 50-2000 nm, and even more preferably 50-1000 nm.

[0028] In this invention, the homopolymer polypropylene a in polypropylene composition A is prone to crystallization during sheet preparation, giving the sheet good rigidity. The high-impact copolymer polypropylene b in the composition has good toughness, which can increase the impact strength of the sheet. In addition, the introduced heat insulation agent not only reduces the thermal conductivity of the composition, but also acts as a filler to a certain extent, thereby reinforcing and modifying the composition.

[0029] According to a preferred embodiment of the present invention, the random copolymer polypropylene x has:

[0030] Melting point is 110-150℃, preferably 120-140℃; and / or,

[0031] The melt flow rate at 230°C and 2.16 kg load is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, more preferably 3-18 g / 10 min; and / or,

[0032] The molecular weight distribution Mw / Mn is 5-12, preferably 7-10; and / or,

[0033] It is a copolymer of propylene and ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene binary copolymer.

[0034] According to a preferred embodiment of the present invention, the thermal adhesive reinforcing agent y has:

[0035] Melting point or viscous flow temperature is 70-110℃; and / or,

[0036] The melt flow rate at 190°C and 2.16 kg load is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, more preferably 1-18 g / 10 min; and / or,

[0037] It is selected from one or more of polyolefin elastomers, ethylene propylene diene monomer (EPDM) rubber, SEBS, SBS, EVA, and petroleum resins; preferably, it is a polyolefin elastomer and / or petroleum resin; more preferably,

[0038] The polyolefin elastomer is a copolymer elastomer of ethylene and propylene and / or α-olefin, wherein the α-olefin is preferably a C4-C12 α-olefin, more preferably 1-butene and / or 1-octene; and / or, the petroleum resin is a C5 and / or C9 hydrogenated petroleum resin with a softening point of 100-150°C; preferably a cyclopentadiene type resin.

[0039] According to a preferred embodiment of the present invention, the heat insulation agent c and the heat insulation agent z may be the same or different, and each is selected from at least one of silica aerogel, titanium dioxide aerogel, graphene aerogel, cellulose aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres; and / or,

[0040] The heat insulation agent c and heat insulation agent z are each spherical and / or near-spherical; and / or,

[0041] The particle size range of the heat insulation agent c and the heat insulation agent z is 50-5000 nm, preferably 50-2000 nm, and more preferably 50-1000 nm; preferably,

[0042] The heat insulation agent c and heat insulation agent z are each selected from at least one of silica aerogel, titanium dioxide aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres; more preferably,

[0043] The heat insulation agent c and heat insulation agent z are each selected from at least one of silica aerogel and maleic anhydride copolymer aerogel, more preferably maleic anhydride copolymer aerogel.

[0044] In this invention, the polypropylene compositions B and B' obtained in the specified proportions, wherein the random copolymer polypropylene x and the heat-bonding reinforcing agent y can expand the temperature and temperature window required for hot pressing of the sheets, the heat-bonding reinforcing agent y promotes the adhesion between the sheets, and the heat insulation agent z can not only improve the heat insulation performance of compositions B and B', but also the preferred maleic anhydride copolymer aerogel can also act as an adhesive, which is beneficial to the adhesion between the sheets and further improves the interlayer peel strength of the sheets.

[0045] The preparation method of the maleic anhydride copolymer aerogel can employ existing methods in the art, including but not limited to the following methods. According to the present invention, a preferred preparation method of the maleic anhydride copolymer aerogel is as follows: adding the maleic anhydride copolymer to water, stirring to dissolve and / or swell it; sequentially subjecting the above solution to gelation, freezing, and freeze-drying treatments to obtain the aerogel material, and then crushing the solid. In a preferred embodiment of the present invention, in the steps, the maleic anhydride copolymer is selected from at least one of maleic anhydride alternating copolymers, maleic anhydride random copolymers, and their derivatives; the weight ratio of the maleic anhydride copolymer to water is (1-50):100, preferably (5-50):100; in the steps, the freezing temperature is -20℃ to -196℃, preferably -80℃ to -196℃; the freeze-drying temperature is -80℃ to -50℃, preferably -50℃ to 30℃; the crushing method can be selected from commonly used industrial methods, with the aim of screening to obtain spherical and / or near-spherical aerogels with a particle size of 50-5000nm, preferably 50-2000nm, and more preferably 50-1000nm.

[0046] According to a preferred embodiment of the present invention, layer A further contains a β-crystal nucleating agent; preferably,

[0047] The β-crystal nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, group IIA two-component complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylate nucleating agents.

[0048] The content range of the β-crystal nucleating agent is relatively wide. Preferably, the content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight relative to 100 parts by weight of polypropylene composition A. Specifically, for example, the content of the β-crystal nucleating agent can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 parts by weight.

[0049] And / or, each of layers A, B and B' contains a surfactant, preferably, the surfactant is selected from at least one of titanate coupling agents, aluminate coupling agents and silane coupling agents; and / or, the weight ratio of the surfactant in layers A, B and B' to the corresponding heat insulation agent c and heat insulation agent z in layers A, B and B' is (0.5-5):100.

[0050] In this invention, when the melt flow rate of polypropylene composition A and polypropylene compositions B and B', the composition ratio of the composition and the thickness distribution of film layer A are within the preferred range, the sheet can be produced stably and has good mechanical strength and thermal insulation properties.

[0051] The heat-insulating polypropylene sheet's BAB ’ The layered structure can be prepared by various methods. In a preferred embodiment of the present invention, the BAB of the heat-insulating polypropylene sheet... ’ The sheet structure is obtained by co-extruding components containing polypropylene composition A and polypropylene compositions B and B'.

[0052] Secondly, the object of the present invention is to provide a method for preparing the heat-insulating polypropylene sheet as described in the first aspect, comprising co-extruding, casting or calendering, and stretching a layer A raw material containing a polypropylene composition A, a layer B raw material containing a polypropylene composition B, and a layer B' raw material containing a polypropylene composition B' according to a BAB' structure to obtain the heat-insulating polypropylene sheet.

[0053] According to the present invention, the contents of the corresponding heat insulation agents c and z in polypropylene composition A, polypropylene composition B, and polypropylene composition B' are not all 0.

[0054] In a preferred embodiment of the present invention, the preparation of the raw material for layer A includes melt blending of the homopolymer polypropylene a, the impact copolymer polypropylene b, and optionally the heat-insulating agent c. The melt blending conditions and equipment for the polypropylene composition A adopt the conditions and equipment for melt blending of polyolefins in the prior art; preferably, the melt temperature is 150-170°C, and the equipment is preferably a twin-screw extruder.

[0055] In a preferred embodiment of the present invention, the preparation of the raw materials for layers B and B' includes melt blending of each component, including the random copolymer polypropylene x, the thermal bonding reinforcing agent y, and optionally the heat insulation agent z. The melt blending conditions and equipment for the polypropylene compositions B and B' adopt the conditions and equipment for melt blending of polyolefins in the prior art. Preferably, the melt temperature is 110-150°C, and the equipment is preferably a twin-screw extruder.

[0056] Preferably, the temperatures for co-extrusion and casting are each independently selected from 200-240°C.

[0057] Preferably, the temperature of the calendering roll is 50-70°C.

[0058] Preferably, the stretching conditions include: a stretching temperature of 90-165°C, more preferably 90-140°C, and even more preferably 90-119°C; and a stretching ratio of 1-20 times, more preferably 2-15 times, and even more preferably 8-16 times.

[0059] According to some embodiments of the present invention, polypropylene composition A, polypropylene composition B, and B' are arranged in a BAB configuration. ’ The structure is co-extruded and then cast or calendered to obtain a heat-insulating polypropylene co-extruded sheet. The extrusion calendering process may include passing the heat-insulating polypropylene co-extruded sheet sequentially through calendering rollers and traction rollers, followed by solid-state stretching, edge trimming, and winding to obtain the heat-insulating sheet. The extrusion casting temperature is 200-230℃, and the calendering roller temperature is 50-70℃. The specific process of preparing the film using the extrusion calendering method is a commonly used choice in the art and will not be elaborated further here.

[0060] Thirdly, the object of the present invention is to provide a heat-insulating polypropylene fabric, which is a three-dimensional polypropylene fabric woven from the heat-insulating polypropylene sheet described in the first aspect or the heat-insulating polypropylene sheet prepared in the second aspect.

[0061] Preferably, the heat-insulating polypropylene fabric is obtained by slitting and weaving the heat-insulating polypropylene sheet; and / or, the heat-insulating polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0062] To facilitate weaving, it is preferable to cut the heat-insulating polypropylene sheet into heat-insulating polypropylene sheets with a width of 2-5mm, and then weave them into heat-insulating polypropylene fabric.

[0063] In a more preferred embodiment of the present invention, the heat-insulating polypropylene fabric is a plain weave, twill weave, satin weave, or three-dimensional heat-insulating polypropylene fabric obtained by weaving a three-layer co-extruded heat-insulating polypropylene stretch flat strip. The three-layer co-extruded heat-insulating polypropylene stretch flat strip comprises at least one layer A formed of a high-melting-point polypropylene composition A, and at least one layer B formed of a low-melting-point polypropylene composition B, and a layer B' formed of a polypropylene composition B'. Polypropylene composition A comprises homopolymer polypropylene a, impact copolymer polypropylene b, and optionally a heat-insulating agent c; polypropylene compositions B and B' comprise random copolymer polypropylene x, a thermal bonding reinforcing agent y, and optionally a heat-insulating agent z, and the polymer layers B and B' are located on top of layer A. i Both sides of the layer.

[0064] Fourthly, the object of the present invention is to provide a heat-insulating polypropylene composite material, which is prepared by hot pressing together multiple layers of heat-insulating polypropylene sheets as described in the first aspect and / or heat-insulating polypropylene fabrics as described in the third aspect.

[0065] Preferably, the heat-insulating polypropylene composite material is prepared by hot pressing multiple layers of the heat-insulating polypropylene sheets or the heat-insulating polypropylene fabric.

[0066] Preferably, the multi-layer heat-insulating polypropylene sheets are stacked from top to bottom at an angle of 0-90° along their respective machine directions.

[0067] Preferably, the multilayer heat-insulating polypropylene fabric is stacked from top to bottom with the warp direction placed at 0-90° between the warp directions.

[0068] Preferably, the multilayer heat-insulating polypropylene sheet and / or multilayer heat-insulating polypropylene fabric has more than or equal to 2 layers, more preferably 2-200 layers; and most preferably 4-100 layers.

[0069] According to a preferred embodiment of the present invention, the heat-insulating polypropylene composite material comprises a plurality of sequentially stacked polypropylene sheet unit groups; each polypropylene sheet unit group includes at least one identical or different polypropylene sheet unit, and each polypropylene sheet unit includes a core layer A. i and located in core layer A i Outer B on both sides i B' i The structure is B i A i B' i The structure of the heat-insulating polypropylene composite material is arranged from bottom to top as group n...group i...group 2, group 1, group 2...group i...group n, and the total number of polypropylene sheet unit groups is 2n-1; i and n are both integers not less than 2, and i≤n;

[0070] Among them, the core layer A in the polypropylene sheet unit i Composition A containing polypropylene i Outer layer B i With outer layer B' i Whether the composition is the same or different, each composition corresponds to a polypropylene composition B. i Polypropylene composition B' i ,

[0071] The polypropylene composition A i The melting point is greater than that of the polypropylene composition B. i The polypropylene composition B' i The melting point of the outer layers in the i-th group is greater than the average melting point of all outer layers in the (i-1)-th group. In the more preferred embodiment of the present invention described above, it is preferable that all outer layers B in the i-th group... i B i The average melting point of ' is greater than that of all outer B layers in group i-1. i B iThe average melting point of '' makes the prepared laminated sheet composition B i A i B i It has superior mechanical properties and interlayer peel strength.

[0072] According to the present invention, in the structure of the polypropylene composite material, the upper i-th group and the lower i-th group may be the same or different.

[0073] According to a preferred embodiment of the present invention, polypropylene composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in melting point is greater than or equal to 5°C, preferably greater than or equal to 10°C, and more preferably greater than or equal to 20°C.

[0074] In this invention, the difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group i-1 may be the same or different, and each is 1-40°C, preferably 1-10°C, and more preferably 1-5°C.

[0075] According to the present invention, the total number of polypropylene sheet unit groups is 2n-1. The present invention has a wide range of options for the total number of polypropylene sheet unit groups. In a preferred embodiment of the present invention, 2≤n≤100, more preferably, 2≤n≤50, and even more preferably, 2≤n≤30.

[0076] According to the present invention, the number of polypropylene sheet units included in each polypropylene sheet unit group can be selected within a wide range. In a preferred embodiment of the present invention, each polypropylene sheet unit group independently includes 1 to 10, preferably 1 to 5, more preferably 1 to 3 identical or different polypropylene sheet units, and even more preferably 1 polypropylene sheet unit. Preferably, the number of polypropylene sheet units included in each polypropylene sheet unit group is the same.

[0077] Preferably, but not necessarily, the melting point of any outer layer in each group is within ±10°C, ±5°C, more preferably within ±3°C, and more preferably within ±1°C of the average melting point of all outer layers in the group.

[0078] In embodiments where each polypropylene sheet unit group comprises only one polypropylene sheet unit, for example, the structure of the polypropylene composite material can be arranged from bottom to top as B n A n B' n ...B i A i B' i...B2A2B'2, B1A1B'1, B2A2B'2...B i A i B' i ...B n A n B' n The total number of layers in the polypropylene sheet unit is 2n-1; i and n are both integers not less than 2, and i≤n.

[0079] In embodiments where each polypropylene sheet unit group comprises two or more polypropylene sheet units, for example, the structure of the i-th polypropylene sheet unit group is B. i1 A i1 B' i1 B i2 A i2 B' i2 ...B ip A ip B' ip The structure of the polypropylene composite material can be arranged from bottom to top as follows: (B) n1 A n1 B' n1 B n2 A n2 B' n2 ...B nq A nq B' nq )……(B i1 A i1 B' i1 B i2 A i2 B' i2 ...B ip A ip B' ip )……(B 21 A 21 B' 21 B 22 A 22 B' 22 ...B 2k A 2k B' 2k (B) 11 A 11 B' 11 B 12 A 12 B' 12 ...B 1j A 1j B' 1j (B) 21 A 21 B' 21 B 22 A 22 B'22 ...B 2k A 2k B' 2k )……(B i1 A i1 B' i1 B i2 A i2 B' i2 ...B ip A ip B' ip )……(B n1 A n1 B' n1 B n2 A n2 B' n2 ...B nq A nq B' nq The total number of polypropylene sheet units stacked is j+2k+……2p+……2q; j, k, p, and q are each independent integers not less than 2, preferably 2 to 10, more preferably 2 to 5, and even more preferably 2 to 3.

[0080] In a preferred embodiment of the present invention, the polypropylene composition A contained in each of the stacked layers of insulating polypropylene fabric is... i They can be the same or different, each layer contains polypropylene fabric A i All can be selected independently, with polypropylene composition A being preferred for each layer. i They are the same.

[0081] In a preferred embodiment of the present invention, the heat-insulating polypropylene composite material has at least one of the following characteristics:

[0082] Longitudinal tensile strength ≥160 MPa, preferably ≥180 MPa;

[0083] Interlayer peel strength ≥1N / mm, preferably ≥1.1N / mm;

[0084] Thermal conductivity ≤0.2W / (m·K), preferably ≤0.18W / (m·K), more preferably ≤0.15W / (m·K)

[0085] Tensile strength was determined according to the method specified in GB / T1040.1-2018, interlaminar peel strength was determined according to the method specified in GB / T2358-1998, and thermal conductivity was determined according to the method specified in GB / T10294-2008. The corresponding test specimens for the above tests are the standard test specimens required in the above test standards.

[0086] Fifthly, the object of the present invention is to provide a method for preparing the heat-insulating polypropylene composite material described in the fourth aspect, the method comprising hot-pressing and fusing the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric into a laminate, and then cooling and shaping it to form the heat-insulating polypropylene composite material.

[0087] Preferably, the conditions of the preparation method include:

[0088] The hot-pressing fusion temperature is 115-170℃, preferably 115-159℃, more preferably 140-159℃; and / or,

[0089] The pressure for hot-pressing fusion is 2-10 MPa; and / or,

[0090] The preheating time for the hot-pressing fusion is 5-600s, and the hot-pressing time is 1-600s, preferably 10-500s; and / or,

[0091] The cooling and setting pressure is 2-8 MPa, and the cooling and setting time is 30-700 s; and / or,

[0092] The number of layers in the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric laminate is greater than or equal to 2 layers, preferably 2-200 layers; more preferably 4-100 layers; and / or,

[0093] The adjacent layers of the thermal insulation polypropylene fabric laminate are placed at 0-90° angles between each other along the warp direction, and the machine direction is the stretching direction (MD); and / or,

[0094] The adjacent layers of the heat-insulating polypropylene sheet stack are placed at 0-90° along their respective machine directions.

[0095] In a more preferred embodiment of the present invention, the method for preparing the heat-insulating polypropylene composite material includes the following steps:

[0096] Step a: Take polypropylene composition A i Polypropylene composition B i B i According to B i A i B i The structure is co-extruded and cast or calendered to obtain heat-insulating polypropylene co-extruded sheets; preferably, the extrusion casting or calendering temperature is 200-240℃, and the calendering roll temperature is 50-70℃;

[0097] Step b: The heat-insulating polypropylene co-extruded sheet is stretched at a certain temperature to obtain a heat-insulating polypropylene stretched sheet; the stretching method is free stretching, and / or solid-phase stretching, and / or multi-stage stretching; the stretching temperature is preferably 90-165℃, more preferably 90-140℃, and even more preferably 90-119℃; the stretching ratio is 1-20 times, preferably 2-15 times; and even more preferably 8-16 times.

[0098] Step c: Cut the heat-insulating polypropylene stretched sheet to prepare heat-insulating polypropylene flat strips, and weave the flat strips to obtain heat-insulating polypropylene fabric; preferably, the width of the heat-insulating polypropylene flat strip is 2-5mm, and the heat-insulating polypropylene fabric includes plain weave, twill weave, satin weave or other three-dimensional polypropylene fabrics.

[0099] Step d: The heat-insulating polypropylene fabrics are sequentially stacked and hot-pressed together, and then cooled and shaped to form a heat-insulating polypropylene composite material; preferably, in step d, the hot-pressing conditions are: hot-pressing temperature 115-170℃, preferably 115-159℃, more preferably 140-159℃; hot-pressing pressure 2-10 MPa, preheating time 5-600s, hot-pressing time 1-600s, preferably 10-500s, cooling pressure 2-8 MPa, cooling time 30s-700s; preferably, adjacent heat-insulating polypropylene fabrics in the heat-insulating polypropylene composite material can be placed at 0-90° between the warp and weft directions.

[0100] According to some embodiments of the present invention, in step c, a high-speed slitting machine with multiple blades can be used to cut the oriented heat-insulating polypropylene flat strip with a width of 2-5 mm; the oriented flat strip is then woven into plain weave, twill weave, satin weave or other three-dimensional heat-insulating polypropylene fabrics using a commercial weaving machine according to the designed fabric structure.

[0101] According to a preferred embodiment of the present invention, the pressure is preferably maintained continuously during the hot pressing and cooling process without any decrease. The hot pressing process is continuous, and preferably a continuous hot pressing composite material molding equipment is adopted, consisting of a preheating machine, a crawler-type continuous planar hot press, a crawler-type continuous planar cooling press, a sheet cutting machine, and a sheet stacking machine arranged in sequence. Preferably, the crawler-type continuous planar hot press has a preheating unit, an independent heating and pressurizing unit, an air cooling unit, and a lifting mechanism.

[0102] In the preparation process, the heat-insulating polypropylene sheets and / or the heat-insulating polypropylene fabrics are sequentially stacked and preheated in a preheating machine. The preheated samples are then sequentially hot-pressed and fused using a tracked flatbed hot press, followed by cooling and shaping using a tracked continuous flatbed cooling press to produce a heat-insulating polypropylene composite material, i.e., a stacked hot-pressed product. Afterwards, the product is sliced ​​as needed using a sheet cutter, and then stacked and arranged using a sheet stacking machine. The hot-pressing temperature is controlled by the preheating unit, independent heating and pressurizing unit, and air-cooling unit in the tracked flatbed hot press, while the hot-pressing pressure is controlled by a lifting mechanism. According to the inventors' research, when the preparation process parameters are within the preferred range, and the aforementioned preparation equipment is used to prepare the heat-insulating polymer composite material, the heat-insulating polymer composite material exhibits good tensile strength, interlaminar peel strength, and thermal conductivity.

[0103] Sixthly, the object of the present invention is to provide an application of the heat-insulating polypropylene sheet described in the first aspect, the heat-insulating polypropylene fabric described in the third aspect, the heat-insulating polypropylene composite material described in the fourth aspect, and the heat-insulating polypropylene composite material prepared by the preparation method described in the fifth aspect in the fields of sports protection, automobile manufacturing, military materials, and consumer products.

[0104] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0105] (1) The heat-insulating polypropylene composite polymer of the present invention has good tensile strength, interlaminar peel strength and heat insulation performance;

[0106] (2) The heat-insulating polypropylene composite material of the present invention is more preferably prepared by the heat-insulating polypropylene composite material with a unique melting point gradient at a lower hot pressing temperature and a wider temperature range, which greatly improves the adhesion of the laminated products. The heat insulation agent is more preferably maleic anhydride copolymer aerogel heat insulation agent, which can also act as an adhesive to a certain extent to maintain the peel force between the sheets.

[0107] (3) The heat-insulating polypropylene composite material of the present invention has high preparation efficiency, mature production process, can be promoted on a large scale, and has a wide range of applications. Detailed Implementation

[0108] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0109] In the following embodiments and comparative examples:

[0110] The extrusion calender and solid phase stretching equipment were purchased from Tianjin Hengrui Company, and the model is HRPC-800 three-layer co-extrusion plastic stretching sheet production line.

[0111] The properties of the heat-insulating polypropylene composition and sheet were tested according to the following methods, and the film test results are shown in Table 1:

[0112] (1) Melt mass flow rate (MFR): The test was conducted according to the method specified in GB / T 3682-2000, where the test temperature was 230℃ and the load was 2.16kg.

[0113] (2) Melting point, determined according to the method specified in GB / T 28724-2012;

[0114] (3) Tensile strength: determined according to the method specified in GB / T1040.1-2018;

[0115] (4) Interlayer peel strength: determined according to the method specified in QB / T2358-1998;

[0116] (5) Thermal conductivity: The thermal conductivity was determined according to the method specified in GB / T10294-2008.

[0117] In the following examples, the β-crystal nucleating agent with the brand name VP101B was sourced from the Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation; the sources of some raw materials are described in the examples, and the remaining raw materials are commercially available unless otherwise specified.

[0118] Example 1

[0119] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0120] (1) Preparation of polypropylene composition A:

[0121] Component a is a homopolymer polypropylene self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 160℃, a melt flow rate of 5.2 g / 10 min, and an isotacticity of 97%; component b is a polypropylene impact copolymer self-produced by the Beijing Research Institute of Chemical Industry of Sinopec (impact strength 23 KJ / m under 23℃ testing conditions). 2 The ethylene content is 11% wt, the melt flow rate is 2.0 g / 10 min, and the melting point is 155℃.

[0122] The preparation method of maleic anhydride copolymer aerogel is as follows: referring to the literature Polymer composites with high haze and high transmittance (DOI:10.1039 / c5py01072a), maleic anhydride-α-methylstyrene alternating copolymer with a particle size of 800 nm was prepared. Then, 5 parts of maleic anhydride-α-methylstyrene alternating copolymer were added to 100 parts of water and allowed to swell fully. The above solution was placed at -80℃ and then freeze-dried at -30℃. After that, it was crushed to obtain maleic anhydride copolymer aerogel with an average particle size of 850 nm.

[0123] The components were weighed and mixed according to the specified proportions, with component a (Wa) comprising 80 parts by weight, component b (Wb) comprising 18 parts by weight, and component c (maleic anhydride aerogel) comprising 2 parts by weight (Wc). 0.05 parts by weight of β-crystal nucleating agent (VP101B) were added. The mixture was then added to a high-speed mixer and mixed thoroughly. The mixed material was then fed into the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws via the feeder. During processing, the screw temperature was maintained between 200-230°C. After melting and mixing evenly in the screws, extrusion, granulation, and drying, polypropylene composition granules were obtained. The melt flow rate (MFRA) was measured to be 4.4 / 10 min; the melting point of polypropylene composition A was 158°C.

[0124] (2) Preparation of polypropylene composition B:

[0125] Component x is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene-butene terpolymer with a melting point of 140℃ and a melt flow rate of 6.6 g / 10 min; component y is a polyolefin elastomer of grade 6102 purchased from ExxonMobil, which is an ethylene-propylene copolymer with an ethylene content of 16% wt and a melt flow rate of 1.4 g / 10 min at 230℃ and a load of 2.16 kg; component z is silica aerogel purchased from Aspen Laboratories, USA, with a particle size of 500 nm.

[0126] The components obtained above were weighed and mixed according to the proportions, wherein the mass fraction of component x, Wx, was 85 parts by weight, the mass fraction of component y, Wy, was 10 parts by weight, and the mass fraction of component z, Wz, was 5 parts by weight. Other steps were the same as in step (1). Finally, polypropylene composition B granules were obtained. The melt flow rate MFRB was tested to be 4.3 g / 10 min, and the melting point was 139 °C.

[0127] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0128] The polypropylene composition A and polypropylene composition B granules obtained in steps (1) and (2) above are dried. Then, polypropylene composition A is added to the core extruder of a multilayer extrusion calender, and polypropylene composition B is added to the upper and lower surface extruders of a multilayer extrusion casting machine.

[0129] After the granules are co-extruded and compounded through the die of an extruder, they pass through calendering rollers and traction rollers in sequence, and then undergo solid-phase stretching, edge trimming and winding to obtain the sheet material.

[0130] The extrusion casting temperature is 230℃, and the calendering roll temperature is 55℃. The solid-phase stretching process is carried out at 135℃, with a stretching rate of 2 m / min and a stretching ratio of 7. After stretching, the film is wound up to form a polypropylene sheet (composite film), which consists of an upper surface layer (film layer A), a core layer (film layer A), and a lower surface layer (film layer B).

[0131] The thickness of the above-mentioned heat-insulating polypropylene sheet (composite film) is 80 μm, wherein the thickness of film layer A accounts for 80% of the total thickness of the sheet.

[0132] (4) Preparation of heat-insulating polypropylene fabric:

[0133] The three-layer co-extruded polypropylene sheet obtained in step (3) above is cut with a high-speed slitting machine with multiple blades to obtain an oriented polypropylene flat strip with a width of 3mm; the oriented flat strip is woven with a commercial weaving machine according to the designed fabric structure to obtain a plain weave heat-insulating polypropylene fabric.

[0134] (5) Preparation of thermally insulating polypropylene composite material:

[0135] The heat-insulating polypropylene fabric obtained in step (4) was sequentially stacked and hot-pressed to form a laminated polypropylene sheet. The laminated polypropylene sheet consisted of 24 layers of polypropylene fabric, with the polypropylene fabrics placed at a 90° angle between the warp and weft directions. The hot-pressing conditions were: temperature 150℃, hot-pressing pressure 5 MPa, preheating time 180 s, hot-pressing time 180 s, and cooling time 600 s. The thickness of the prepared heat-insulating polypropylene composite material was 1.67 mm.

[0136] Example 2

[0137] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0138] (1) Preparation of polypropylene composition A:

[0139] Component a is a homopolymer polypropylene self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 165℃, a melt flow rate of 8.1 g / 10 min, and an isotacticity of 97%; component b is a polypropylene impact copolymer self-produced by the Beijing Research Institute of Chemical Industry of Sinopec, with an impact strength of 25 KJ / m under a test condition of 23℃. 2 The ethylene content is 8% wt, the melt flow rate is 3.2 g / 10 min, and the melting point is 155℃.

[0140] The components were weighed and mixed according to the specified proportions, with component a (Wa) comprising 65 parts by weight, component b (Wb) comprising 30 parts by weight, and component c (the same as the maleic anhydride copolymer aerogel in Example 1) comprising 5 parts by weight (Wc). 0.05 parts by weight of β-crystal nucleating agent (VP101B) were added. The mixture was then added to a high-speed mixer and mixed thoroughly. The mixed material was then fed into the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws via the feeder. During processing, the screw temperature was maintained between 200-230°C. After melting and mixing evenly in the screws, extrusion, granulation, and drying, polypropylene composition granules were obtained. The melt flow rate (MFRA) was measured to be 6.1 / 10 min, and the melting point of polypropylene composition A was 160°C.

[0141] (2) Preparation of polypropylene composition B:

[0142] Component x is a random copolymer polypropylene produced by the Beijing Research Institute of Chemical Industry of Sinopec, with a melting point of 134℃. It is an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min. Component y is a polyolefin elastomer produced by the Beijing Research Institute of Chemical Industry of Sinopec, which is an ethylene-propylene copolymer with an ethylene content of 15% wt. It has a melting point of 105℃ and a melt flow rate of 9 g / 10 min at 230℃ and a load of 2.16 kg. Silica aerogel was purchased from Aspen Laboratories, USA, with a particle size of 500 nm.

[0143] The components obtained above were weighed and mixed according to the specified proportions, wherein component x (Wx) had a mass fraction of 75 parts by weight, component y had a mass fraction of 15 parts by weight, and component z (the weight ratio of silica aerogel to maleic anhydride copolymer aerogel of Example 1 was 1:1) had a mass fraction of 10 parts by weight. Other steps were the same as in step (1). Finally, polypropylene composition B granules were obtained, and its melt flow rate (MFRB) was measured to be 6.4 g / 10 min. The melting point of polypropylene composition B was 129 °C.

[0144] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0145] The preparation process is the same as step (3) in Example 1.

[0146] (4) Preparation of heat-insulating polypropylene fabric:

[0147] The preparation process is the same as step (4) in Example 1.

[0148] (5) Preparation of thermally insulating polypropylene composite material:

[0149] The preparation process is the same as step (5) in Example 1.

[0150] The thickness of the prepared heat-insulating polypropylene composite material is similar to that of Example 1.

[0151] Example 3

[0152] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0153] (1) Preparation of polypropylene composition A:

[0154] Same as in Example 1, wherein component a (Wa) has a mass fraction of 94.5 parts by weight, component b (Wb) has a mass fraction of 5 parts by weight, and component c (Wc) has a mass fraction of 0.5 parts by weight. 0.05 parts by weight of β-crystal nucleating agent (VP101B) is added. Polypropylene composition A granules are obtained, and its melt flow rate (MFRA) is measured to be 4.5 / 10 min. The melting point of polypropylene composition A is 158°C.

[0155] (2) Preparation of polypropylene composition B:

[0156] Same as in Example 1, wherein the mass fraction of component x, Wx, is 94 parts by weight, the mass fraction of component y, Wy, is 5 parts by weight, and the mass fraction of component z, Wz, is 1 part by weight, and finally polypropylene composition B granules are obtained. The melt flow rate MFRB was tested to be 5.1 g / 10 min, and the melting point of polypropylene composition B is 139°C.

[0157] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0158] The preparation process is the same as step (3) in Example 1.

[0159] (4) Preparation of heat-insulating polypropylene fabric:

[0160] The preparation process is the same as step (4) of Example 1.

[0161] (5) Preparation of thermally insulating polypropylene composite material:

[0162] The preparation process is the same as step (5) in Example 1.

[0163] The thickness of the prepared heat-insulating polypropylene composite material is similar to that of Example 1.

[0164] Example 4

[0165] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0166] (1) Preparation of polypropylene composition A:

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

[0168] (2) Preparation of polypropylene composition B:

[0169] The preparation process is the same as step (2) of Example 1.

[0170] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0171] The main steps are the same as in Example 1. The thickness of the polypropylene sheet is 80 μm, wherein the thickness of the film layer A accounts for 90% of the total thickness of the sheet.

[0172] (4) Preparation of heat-insulating polypropylene fabric:

[0173] The preparation process is the same as step (4) of Example 1.

[0174] (5) Preparation of thermally insulating polypropylene composite material:

[0175] The preparation process is the same as step (5) in Example 1.

[0176] The thickness of the prepared heat-insulating polypropylene composite material is similar to that of Example 1.

[0177] Example 5

[0178] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0179] (1) Preparation of polypropylene composition A:

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

[0181] (2) Preparation of polypropylene composition B:

[0182] The preparation process is the same as step (2) of Example 1.

[0183] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0184] The main steps are the same as in Example 1. The thickness of the polypropylene sheet is 80 μm, wherein the thickness of the film layer A accounts for 70% of the total thickness of the sheet.

[0185] (4) Preparation of heat-insulating polypropylene fabric:

[0186] The preparation process is the same as step (4) of Example 1.

[0187] (5) Preparation of thermally insulating polypropylene composite material:

[0188] The preparation process is the same as step (5) in Example 1.

[0189] The thickness of the prepared heat-insulating polypropylene composite material is similar to that of Example 1.

[0190] Example 6

[0191] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0192] (1) Preparation of polypropylene composition A:

[0193] The preparation process is the same as step (1) in Example 1.

[0194] (2) Preparation of polypropylene composition B:

[0195] The preparation process is the same as step (2) of Example 1.

[0196] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0197] The main preparation process is the same as step (3) in Example 1. The sheet stretching ratio is 10 times.

[0198] (4) Preparation of heat-insulating polypropylene fabric:

[0199] The preparation process is the same as step (4) of Example 1.

[0200] (5) Preparation of thermally insulating polypropylene composite material:

[0201] The preparation process is the same as step (5) in Example 1.

[0202] The thickness of the prepared heat-insulating polypropylene composite material is similar to that of Example 1.

[0203] Example 7

[0204] This embodiment illustrates the preparation of the heat-insulating polypropylene composition, the three-layer co-extruded heat-insulating polypropylene sheet, the heat-insulating polypropylene fabric, and the heat-insulating polypropylene composite material provided by the present invention.

[0205] (1) Preparation of polypropylene composition A:

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

[0207] (2) Preparation of polypropylene composition B:

[0208] The preparation process is the same as step (2) of Example 1.

[0209] (3) Preparation of three-layer co-extruded heat-insulating polypropylene sheets:

[0210] The main preparation process is the same as step (3) of Example 1. Among them, the stretching process is multi-stage stretching. In the first stage of solid-phase stretching, the temperature is 138℃, the stretching rate is 2m / min, and the stretching ratio is 7 times. The stretched sheet is then subjected to a second stage of free stretching at a temperature of 140℃, a stretching rate of 0.5m / min, and a stretching ratio of 2 times.

[0211] The resulting heat-insulating polypropylene sheet (composite film) has a stretch ratio of 14 times.

[0212] (4) Preparation of heat-insulating polypropylene fabric:

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

[0214] (5) Preparation of thermally insulating polypropylene composite material:

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

[0216] The thickness of the prepared heat-insulating polypropylene composite material is 1.54 mm.

[0217] Example 8

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

[0219] (1) Polypropylene composition A i Preparation:

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

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

[0222] Component x1 is random copolymer polypropylene self-made by Sinopec Beijing Chemical Research Institute, which is an ethylene-propylene-butene terpolymer with a melting point of 130℃ and a melt flow rate of 8.1 g / 10 min; Component x2 is random copolymer polypropylene self-made by Sinopec Beijing Chemical Research Institute, which is an ethylene-propylene-butene terpolymer with a melting point of 135℃ and a melt flow rate of 7.2 g / 10 min; Component x3, Component y, and Component z are the same as in step (2) of Example 1.

[0223] The preparation of B1, B2, and B3 is the same as step (2) in Example 1. After testing, their melting points are 128℃, 133℃, and 139℃, respectively.

[0224] (3) Preparation of three-layer co-extruded polypropylene sheets:

[0225] The same as step (3) of Example 1, the resulting sheets are B1A1B1, B2A2B2, B3A3B3, where A1, A2, and A3 are the same.

[0226] (4) Preparation of heat-insulating polypropylene fabric:

[0227] Same as step (4) in Example 1.

[0228] (5) Preparation of thermally insulating polypropylene composite material:

[0229] The heat-insulating polypropylene fabrics obtained in step (4) above are stacked in sequence, from bottom to top as B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3, with a total of 5 layers. The stacked polypropylene fabrics are hot-pressed and fused together, and then cooled and shaped to form a polypropylene composite material. The hot-pressing conditions are the same as in step (5) of Example 1. The thickness of the resulting heat-insulating polypropylene composite material is 394 μm.

[0230] Example 9

[0231] Three-layer co-extruded polypropylene sheets, polypropylene fabrics, and polypropylene composites were prepared according to the method of Example 1, except that A... i The heat insulation agent in the middle is replaced with the same mass of silica aerogel.

[0232] Example 10

[0233] Three-layer co-extruded polypropylene sheets, polypropylene fabrics, and polypropylene composites were prepared according to the method of Example 1, except that no heat insulation agent was added to A.

[0234] Example 11

[0235] Three-layer co-extruded polypropylene sheets, polypropylene fabrics, and polypropylene composites were prepared according to the method of Example 1, except that no heat insulation agent was added in B.

[0236] Comparative Example 1

[0237] Three-layer co-extruded polypropylene sheets, polypropylene fabrics, and polypropylene composites were prepared according to the method of Example 1, except that heat insulation agents were not added to A and B.

[0238] Comparative Example 2

[0239] Three-layer co-extruded polypropylene sheets, polypropylene fabrics, and polypropylene composites were prepared according to the method of Example 8, except that the lamination method in step (5) was replaced with B1A1B1, B2A2B2, B3A3B3, B2A2B2, B1A1B1.

[0240] Table 1

[0241] sample Tensile strength (MPa) Peel strength (N / mm) Thermal conductivity (W / (m·K)) Example 1 196 1.18 0.13 Example 2 192 1.25 0.09 Example 3 210 1.09 0.17 Example 4 212 1.10 0.12 Example 5 182 1.13 0.12 Example 6 281 1.19 0.11 Example 7 379 1.22 0.10 Example 8 194 1.44 0.13 Example 9 193 1.15 0.13 Example 10 192 1.17 0.15 Example 11 191 1.21 0.15 Comparative Example 1 188 1.19 0.22 Comparative Example 2 190 0.77 0.14

[0242] As can be seen from the data in Table 1, the heat-insulating polypropylene composite material prepared by the method described in this invention has good tensile strength, peel strength, and low thermal conductivity. From Example 1 and Comparative Example 1, it can be seen that the tensile strength of the polypropylene composite material is improved after the addition of the heat-insulating agent, indicating that the heat-insulating agent has a certain reinforcing effect; moreover, the addition of the heat-insulating agent has little effect on the interlaminar peel strength of the composite material, mainly because the preferred heat-insulating agent used is maleic anhydride copolymer aerogel containing anhydride groups, which can compatibilize the polypropylene; more importantly, the heat-insulating agent can significantly reduce the thermal conductivity of the composite material.

[0243] Furthermore, as can be seen from Examples 6 and 7, after being stretched at a higher ratio, the peel strength of the polypropylene composite material is improved and the thermal conductivity is reduced. This is because stretching makes the interaction between the heat insulation agent and the substrate stronger and the dispersion more uniform.

[0244] More importantly, as can be seen from Example 8, Comparative Example 2 and other examples, by introducing a melting point gradient, that is, the average melting point of all outer layers in group i is greater than the average melting point of all outer layers in group i-1, the overall performance of the resulting heat-insulating polypropylene composite material is optimal.

[0245] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0246] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

Claims

1. A heat-insulating polypropylene sheet with a structure of BAB', comprising layer A and layers B and B' located on both sides of layer A; wherein layer A contains a polypropylene composition A, said polypropylene composition A comprising homopolymer polypropylene a, impact copolymer polypropylene b, and optionally a heat-insulating agent c; Layer B may be the same as or different from layer B', and each contains a polypropylene composition B and a polypropylene composition B', wherein each of the polypropylene composition B and the polypropylene composition B' includes random copolymer polypropylene x, thermal bonding reinforcing agent y, and optional heat insulation agent z; and the contents of the corresponding heat insulation agents c and z in polypropylene composition A, polypropylene composition B, and polypropylene composition B' are not all 0 at the same time. in, The melting point of polypropylene composition A is greater than that of polypropylene composition B and polypropylene composition B'. The heat insulation agent c and the heat insulation agent z may be the same or different, and each is selected from at least one of silica aerogel, titanium dioxide aerogel, graphene aerogel, cellulose aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres.

2. The heat-insulating polypropylene sheet according to claim 1, characterized in that: Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 50-99 wt% homopolymer polypropylene a, 1-40 wt% impact copolymer polypropylene b, 0-10 wt% thermal insulation agent c; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 60-99 wt% random copolymer polypropylene x, 1-20 wt% thermal bonding reinforcing agent y, and 0-20 wt% heat insulation agent z. And / or, each of layers A, B and B' contains a surfactant.

3. The heat-insulating polypropylene sheet according to claim 1, characterized in that: Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 65-94.5 wt% homopolymer polypropylene a, 5-30 wt% impact copolymer polypropylene b, and 0.5-5 wt% thermal insulation agent c; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', each of the polypropylene composition B and the polypropylene composition B' comprises 75-94 wt% random copolymer polypropylene x, 5-15 wt% heat-bonding reinforcing agent y, and 1-10 wt% heat insulation agent z. And / or, each of layers A, B, and B' further contains a surfactant, wherein the surfactant is selected from at least one of titanate coupling agents, aluminate coupling agents, and silane coupling agents; and / or, each of layers A, B, and B' further contains a surfactant, wherein the weight ratio of the surfactant in layers A, B, and B' to the corresponding heat insulation agent c and heat insulation agent z in layers A, B, and B' is (0.5-5):

100.

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

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

6. The heat-insulating polypropylene sheet according to claim 1, characterized in that: The difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B, and the difference between the melting point of polypropylene composition A and the melting point of polypropylene composition B', are each greater than or equal to 20°C; and / or, Based on the total thickness of the heat-insulating polypropylene sheet, the thickness of layer A accounts for 71%-80% of the total thickness.

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

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

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

10. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The impact-resistant copolymer polypropylene b has a melting point of 150-170℃: and / or, The monomer for the copolymerization of the impact-resistant polypropylene b and propylene is ethylene or butene; and / or, The impact-resistant copolymer polypropylene b has a melt flow rate of 0.5-50 g / 10 min at 230°C and a load of 2.16 kg; and / or, The cantilever beam impact strength of the impact-resistant copolymer polypropylene b is not less than 20 KJ / m. 2 .

11. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The monomer for the copolymerization of the impact-resistant polypropylene b and propylene is butene; and / or, The impact-resistant copolymer polypropylene b has a melt flow rate of 1-20 g / 10 min at 230°C and 2.16 kg load.

12. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The impact-resistant copolymer polypropylene b has a melt flow rate of 2.5-18 g / 10 min at 230°C and 2.16 kg load.

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

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

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

16. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The thermal bonding enhancer y has the following characteristics: Melting point or viscous flow temperature is 70-110℃; and / or, The melt flow rate at 190℃ and 2.16kg load is 0.5-50g / 10min.

17. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The thermal bonding enhancer y has the following characteristics: The melt flow rate at 190℃ and 2.16kg load is 1-20g / 10min.

18. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The thermal bonding enhancer y has the following characteristics: The melt flow rate at 190℃ and 2.16kg load is 1-18g / 10min.

19. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The heat-adhesive reinforcing agent y is selected from one or more of polyolefin elastomers, ethylene propylene diene monomer (EPDM) rubber, SEBS, SBS, EVA, and petroleum resin.

20. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The heat-adhesive reinforcing agent y is a polyolefin elastomer and / or petroleum resin.

21. The heat-insulating polypropylene sheet according to claim 19, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene with propylene and / or α-olefins.

22. The heat-insulating polypropylene sheet according to claim 21, characterized in that: The α-olefin is a C4-C12 α-olefin.

23. The heat-insulating polypropylene sheet according to claim 21, characterized in that: The α-olefin is 1-butene and / or 1-octene.

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

25. The heat-insulating polypropylene sheet according to claim 19, characterized in that: The petroleum resin is a cyclopentadiene type resin.

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

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

28. The heat-insulating polypropylene sheet according to claim 27, characterized in that: The β-crystal nucleating agent is selected from at least one of polycyclic aromatic hydrocarbons, group IIA binary complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylate nucleating agents; and / or, The content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight relative to 100 parts by weight of polypropylene composition A.

29. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The heat insulation agent c and heat insulation agent z are each spherical and / or near-spherical.

30. The heat-insulating polypropylene sheet according to claim 29, characterized in that: The particle size range of the heat insulation agent c and the heat insulation agent z is 50-5000 nm.

31. The heat-insulating polypropylene sheet according to claim 29, characterized in that: The particle size range of the heat insulation agent c and the heat insulation agent z is 50-2000 nm.

32. The heat-insulating polypropylene sheet according to claim 29, characterized in that: The particle size range of the heat insulation agent c and the heat insulation agent z is 50-1000 nm.

33. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The heat insulation agent c and heat insulation agent z are each selected from at least one of silica aerogel, titanium dioxide aerogel, maleic anhydride copolymer aerogel, and porous glass microspheres.

34. The heat-insulating polypropylene sheet according to any one of claims 1-6, characterized in that: The heat insulation agent c and heat insulation agent z are each selected from at least one of silica aerogel and maleic anhydride copolymer aerogel.

35. A method for preparing the heat-insulating polypropylene sheet according to any one of claims 1-34, comprising co-extruding, casting or calendering, and stretching a layer A raw material containing a polypropylene composition A, a layer B raw material containing a polypropylene composition B, and a layer B' raw material containing a polypropylene composition B' according to a BAB' structure to obtain the heat-insulating polypropylene sheet.

36. The method for preparing the heat-insulating polypropylene sheet according to claim 35, characterized in that, The preparation of the raw material for layer A includes melt blending the components, including the homopolymer polypropylene a, the impact copolymer polypropylene b, and optionally the thermal insulation agent c; and / or, The preparation of the raw materials for layers B and B' includes the melt blending of each component, including the random copolymer polypropylene x, the thermal bonding reinforcing agent y, and the optional thermal insulation agent z; and / or, The temperatures for co-extrusion and casting are each independently selected from 200-240°C; and / or, The temperature of the calender rolls is 50-70℃; and / or, The stretching conditions include: a stretching temperature of 90-165℃; and a stretching ratio of 1-20 times.

37. The method for preparing the heat-insulating polypropylene sheet according to claim 35, characterized in that, The stretching conditions include: a stretching temperature of 90-140℃ and a stretching ratio of 1-20 times.

38. The method for preparing the heat-insulating polypropylene sheet according to claim 35, characterized in that, The stretching conditions include: a stretching temperature of 90-119℃ and a stretching ratio of 1-20 times.

39. A heat-insulating polypropylene fabric, a three-dimensional polypropylene fabric obtained by weaving the heat-insulating polypropylene sheet according to any one of claims 1-34.

40. The heat-insulating polypropylene fabric according to claim 39, characterized in that: The heat-insulating polypropylene fabric is obtained by cutting and weaving the heat-insulating polypropylene sheet; and / or, the heat-insulating polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

41. A heat-insulating polypropylene composite material, wherein the heat-insulating polypropylene composite material is prepared by hot pressing together multiple layers of heat-insulating polypropylene sheets according to any one of claims 1-34 and / or heat-insulating polypropylene fabrics according to claims 39 or 40.

42. The thermally insulating polypropylene composite material according to claim 41, characterized in that: Thermally insulating polypropylene composite material is prepared by hot pressing multiple layers of the aforementioned thermally insulating polypropylene sheets or the aforementioned thermally insulating polypropylene fabric; and / or, Multi-layer insulating polypropylene sheets are stacked from top to bottom at 0-90° angles along their respective machine directions; and / or, Multi-layer thermal insulation polypropylene fabric is stacked from top to bottom with warp directions arranged at 0-90° intervals; and / or, The number of layers in the multi-layer thermal insulation polypropylene sheet and / or multi-layer thermal insulation polypropylene fabric is greater than or equal to 2.

43. The thermally insulating polypropylene composite material according to claim 41, characterized in that: The number of layers in multi-layer thermal insulation polypropylene sheets and / or multi-layer thermal insulation polypropylene fabrics ranges from 2 to 200.

44. The thermally insulating polypropylene composite material according to claim 41, characterized in that: The number of layers in multi-layer insulating polypropylene sheets and / or multi-layer insulating polypropylene fabrics ranges from 4 to 100.

45. The thermally insulating polypropylene composite material according to any one of claims 41-44, characterized in that: The thermally insulating polypropylene composite material comprises multiple sequentially stacked polypropylene sheet unit groups; each polypropylene sheet unit group includes at least one identical or different polypropylene sheet unit, and each polypropylene sheet unit includes a core layer A. i and located in core layer A i Outer B on both sides i B' i The structure is B i A i B' i The structure of the heat-insulating polypropylene composite material, from bottom to top, is group n...group i...group 2, group 1, group 2...group i...group n, and the total number of polypropylene sheet unit groups is 2n-1. Both i and n are integers not less than 2, and i ≤ n; Among them, the core layer A in the polypropylene sheet unit i Composition A containing polypropylene i Outer layer B i With outer layer B' i Whether the composition is the same or different, each composition corresponds to a polypropylene composition B. i Polypropylene composition B' i , The polypropylene composition A i The melting point is greater than that of the polypropylene composition B. i The polypropylene composition B' i The melting point of the outermost layer in the i-th group is greater than the average melting point of the outermost layer in the (i-1)-th group.

46. ​​The thermally insulating polypropylene composite material according to claim 45, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 5°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group (i-1) is the same or different, and each is between 1 and 40°C; and / or, 2≤n≤100; and / or, Each polypropylene sheet unit group, independently, comprises 1 to 10 identical or different polypropylene sheet units.

47. The thermally insulating polypropylene composite material according to claim 45, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 10°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group (i-1) is the same or different, each ranging from 1 to 10 °C; and / or, 2≤n≤50; and / or, Each polypropylene sheet unit group, independently, comprises 1 to 5 identical or different polypropylene sheet units.

48. The thermally insulating polypropylene composite material according to claim 45, characterized in that: Polypropylene Composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in their melting points is greater than or equal to 20°C; and / or, The difference between the average melting point of all outer layers in group i and the average melting point of all outer layers in group i-1, whether the difference is the same or different, is 1-5℃.

49. A method for preparing a heat-insulating polypropylene composite material according to any one of claims 41-48, the method comprising hot-pressing and fusing the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric together, and then cooling and shaping it to form a heat-insulating polypropylene composite material.

50. The method for preparing the heat-insulating polypropylene composite material according to claim 49, characterized in that: The hot-pressing fusion temperature is 115-170℃; and / or, The pressure for hot-pressing fusion is 2-10 MPa; and / or, The preheating time for the hot-pressing fusion is 5-600s, and the hot-pressing time is 1-600s; and / or, The cooling and setting pressure is 2-8 MPa, and the cooling and setting time is 30-700 s; and / or, The number of layers in the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric laminate is greater than or equal to two; and / or Adjacent layers of the thermally insulating polypropylene fabric laminate are positioned at 0-90° angles between each other along the warp direction; and / or, The adjacent layers of the heat-insulating polypropylene sheet stack are placed at 0-90° along their respective machine directions.

51. The method for preparing the heat-insulating polypropylene composite material according to claim 49, characterized in that: The hot-pressing fusion temperature is 115-159℃; and / or, The preheating time for the hot-pressing fusion is 5-600s, and the hot-pressing time is 10-500s; and / or, The number of layers in the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric stack is 2-200.

52. The method for preparing the heat-insulating polypropylene composite material according to claim 49, characterized in that: The number of layers in the heat-insulating polypropylene sheet and / or the heat-insulating polypropylene fabric stack is 4-100.

53. The application of the heat-insulating polypropylene sheet according to any one of claims 1-34, the heat-insulating polypropylene fabric according to claim 39 or 40, the heat-insulating polypropylene composite material according to any one of claims 41-48, and the heat-insulating polypropylene composite material prepared by the preparation method according to any one of claims 49-52 in the fields of military materials, automobile manufacturing, and consumer goods.

54. The application according to claim 53, characterized in that: The application is in the consumer products sector, specifically for sports protection.