A multilayer reinforced composite thermoplastic elastomer foamed sheet and a method of preparing and use thereof

Abstract

The application belongs to the technical field of polymer materials, and particularly relates to a kind of multilayer reinforced composite thermoplastic elastomer foamed sheet and its preparation method and application.The multilayer reinforced composite foamed sheet has a laminated structure, including at least two layers of reinforced composite sheet and at least one layer of thermoplastic elastomer composition foamed sheet, and the outer layer of the multilayer reinforced composite foamed sheet is the reinforced composite sheet;The reinforced composite sheet includes at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from polypropylene sheet;Wherein, the polypropylene sheet includes layer A and layer B, B' on both sides of layer A, the structure is BAB';The thermoplastic elastomer composition foamed sheet and the reinforced composite sheet are bonded by hot pressing fusion.The multilayer reinforced composite thermoplastic elastomer foamed sheet has excellent apparent density, physical properties and thermal insulation performance, and also has the advantages of high strength, high impact resistance and high peel strength, and is easy to recycle.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to a multi-layer reinforced composite thermoplastic elastomer foamed sheet and a preparation method and application thereof. BACKGROUND

[0002] Polyolefin thermoplastic elastomer (POE) is an elastic material composed of two components of rubber and polyolefin. Taking ethylene-based thermoplastic elastomer as an example, the crystalline region of the polyethylene chain as the resin phase mainly plays the role of physical crosslinking point, and the introduction of a certain amount of α-olefin can weaken the crystalline region of the polyethylene chain to form a so-called rubber phase (the amorphous region of the rubber elastomer). The relative molecular mass distribution of POE is very narrow and the branched chain is short, so it has excellent physical and mechanical properties (good elasticity, high strength, large elongation), and its molecular chain is saturated, and the content of tertiary carbon atoms is less, so POE also has excellent heat aging resistance and ultraviolet resistance. The narrow relative molecular mass distribution makes the material not easy to produce flexure in the injection and extrusion process. Because POE has high strength and elongation, and has excellent aging resistance, for products with no strict requirements on heat resistance grade and permanent deformation, POE can be directly used to process products, which can improve production efficiency and also can be recycled. In order to reduce the cost of raw materials and improve the performance of the material (such as tear strength, hardness, etc.), a certain amount of filler, reinforcing agent and processing aid need to be added during compounding, so as to improve the comprehensive performance and reduce the cost.

[0003] POE foamed material has excellent properties such as impact resistance, shock resistance, heat insulation, sound absorption, moisture resistance, etc. As a kind of polyolefin thermoplastic elastomer composition foamed material, the rebound rate and other properties of POE / EVA composite foamed material are better than those of traditional foamed materials such as pure EVA (ethylene-vinyl acetate copolymer). The application of foamed material is not only limited to shoe sole material, and there are two large categories of foamed slippers and sports shoes midsole, each of which is divided into two directions of super elasticity and super lightness; in the field of sports and leisure, POE composite foamed material also has a large number of expanded applications, such as common yoga mats, sun hats, life jackets, kickboards, helmet shock pads, and even home soundproof wallpaper. When used as lightweight structural material, POE foamed material has low scratch resistance and low bending modulus, and is easy to scratch and deform during long-term use, thereby affecting the use performance.

[0004] In order to further improve the physical properties of the polyolefin thermoplastic elastomer composition foamed sheet product, at present, the inorganic or organic reinforcing sheet is compounded on the surface of the polyolefin thermoplastic elastomer composition foamed sheet, which has become a new emerging process scheme. The reinforcing sheet compounded in the existing technology is mainly the composite material of glass fiber / carbon fiber reinforced thermoplastic resin due to the high requirement on mechanical properties, and these reinforcing sheets are prone to have compatibility problems with the polyolefin thermoplastic elastomer composition foamed sheet, which leads to the difficulty in achieving the ideal compression and heat insulation physical properties. Even if the polyolefin thermoplastic elastomer foamed sheet product meeting the product performance is successfully obtained, the apparent density is large, the molding time is long, the energy consumption is high and other problems are caused due to the existence of the reinforcing sheet, and after mixing the reinforcing phase material (such as glass fiber, carbon fiber) other than the polyolefin thermoplastic elastomer, it is difficult to recycle. It is expected to have a high-strength high-impact polyolefin composite sheet applied to the surface of the polyolefin thermoplastic elastomer foamed sheet, and the polyolefin thermoplastic elastomer foamed sheet product does not need to be separated and treated during recycling, and can be directly crushed and melted, and then granulated for application. However, the conventional polyolefin composite sheet either does not meet the strength requirement, or does not meet the impact resistance requirement, or does not meet the interlayer peeling strength requirement, and there is no polyolefin composite sheet with high strength, high impact resistance and high peeling strength, therefore, how to provide a polyolefin composite sheet with high strength, high impact resistance and high peeling strength as a reinforcing composite thermoplastic elastomer foamed sheet is the research purpose of the present application. SUMMARY

[0005] In view of the above deficiencies of the prior art, the present application provides a multi-layer reinforced composite thermoplastic elastomer foamed sheet and a preparation method and application thereof. The foamed sheet is composed of a polypropylene laminated material and a thermoplastic elastomer composition foamed sheet. Specifically, the multi-layer reinforced composite thermoplastic elastomer foamed sheet uses a high-strength and high-impact polypropylene composite sheet as a reinforced composite sheet of the thermoplastic polyolefin elastomer composite foamed material, so that the multi-layer reinforced composite thermoplastic elastomer foamed sheet has excellent apparent density, physical properties and thermal insulation performance, and also has the advantages of high strength, high impact resistance and high peel strength. Furthermore, compared with other pre-reinforced sheets of non-pure polyolefin materials on the market, the compatibility of the multi-layer reinforced composite thermoplastic elastomer foamed sheet is greatly improved, and it can be directly crushed and melted for regranulation application without separation treatment during recycling. The multi-layer reinforced composite thermoplastic elastomer foamed sheet has a broad market prospect in the technical field of thermoplastic polyolefin elastomer composition foamed sheet. The present inventors have found that the thermoplastic elastomer composition foamed material and the reinforced composite sheet form a sandwich structure. The thermoplastic elastomer composition foamed material has good cushioning and energy absorption performance, which increases the drop hammer impact strength of the multi-layer reinforced composite thermoplastic elastomer foamed sheet, reduces the density, realizes lightweight while reducing the thermal conductivity, and the reinforced composite sheet improves the tensile strength of the thermoplastic elastomer composition foamed material. In this way, the application fields of the two materials can be effectively expanded, such as the thermoplastic elastomer composition foamed material in the high-mechanical requirement thermal insulation field, and the polypropylene reinforced material in the lightweight application field.

[0006] The first aspect of the present application provides a multi-layer reinforced composite foamed sheet (i.e. a multi-layer reinforced composite thermoplastic elastomer foamed sheet) having a laminated structure, comprising at least two layers of reinforced composite sheets and at least one layer of thermoplastic elastomer composition foamed sheet, and the outer layers of the multi-layer reinforced composite foamed sheet are both reinforced composite sheets;

[0007] The reinforced composite sheet comprises at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from polypropylene sheet; wherein the polypropylene sheet comprises layer A and layers B and B' on both sides of layer A, and the structure is BAB';

[0008] Wherein layer A contains polypropylene composition A, and layer B and layer B' are the same or different, each containing polypropylene composition B and polypropylene composition B', and the melting point of the polypropylene composition A is higher than the melting points of the polypropylene composition B and the polypropylene composition B';

[0009] Wherein the polypropylene composition A comprises homopolymer polypropylene a and impact copolymer polypropylene b; and the polypropylene composition B and the polypropylene composition B' each comprises random copolymer polypropylene x and thermal bonding enhancer y;

[0010] The thermoplastic elastomer composition foamed sheet and the reinforced composite sheet are fused and bonded by hot pressing.

[0011] According to the present application, the layers B, B' on both sides of the layer A are the same or different, and in a preferred embodiment of the present application, the layers B, B' on both sides of the layer A are the same.

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

[0013] According to some preferred embodiments of the present application, the polypropylene composition B and the polypropylene composition B' each comprises 70-99 wt% of the random copolymer polypropylene x and 1-30 wt% of the thermal bonding enhancer y, based on the total weight of the polypropylene composition B and the polypropylene composition B' respectively; preferably, the polypropylene composition B and the polypropylene composition B' each comprises 80-90 wt% of the random copolymer polypropylene x and 10-20 wt% of the thermal bonding enhancer y.

[0014] According to some preferred embodiments of the present application, the thickness of the layer A accounts for 51-89% of the total thickness, preferably 71-89%, and further preferably 71-80%, based on the total thickness of the polypropylene sheet.

[0015] The thickness of the layers B, B' on both sides of the layer A can be the same or different, and preferably the same.

[0016] The present application does not limit the thickness of the polypropylene sheet, which can be selected within a wide range according to its actual application field. Preferably, the thickness of the polypropylene sheet can be 10-1000 μm, preferably 30-500 μm, and further preferably 50-300 μm.

[0017] According to the present application, the thickness of the layers A, B, B' can be controlled by the melt pump of the extruder during the processing.

[0018] According to some preferred embodiments of the present application, the homopolymer polypropylene a has a melting point of 150-170°C, preferably 160-170°C; and / or a melt flow rate of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, and further preferably 2.5-18 g / 10 min, under a load of 2.16 kg at 230°C; and / or an isotacticity (mm) of no less than 96%.

[0019] According to some preferred embodiments of the present application, the impact copolymer polypropylene b has: a melting point of 150-170°C; and / or, the monomer copolymerized with propylene in the impact copolymer polypropylene b is ethylene or butene, preferably butene; and / or, the melt flow rate of the impact copolymer polypropylene b at 230°C under a load of 2.16 kg is 0.5-50 g / 10 min, preferably 1-20 g / 10 min, further preferably 2.5-18 g / 10 min; and / or, the Izod impact strength of the impact copolymer polypropylene b is not less than 20 KJ / m 2 (23°C).

[0020] According to the research of the present inventors, when the melt mass flow rate and the polymer composition ratio of the polypropylene composition A are within the above-mentioned preferred ranges, the high-impact copolymer polypropylene b in the composition can better absorb impact energy, meet the requirements of impact performance, and make the sheet have good impact performance. At the same time, because the macromolecular chain segments in the homopolymer polypropylene a are relatively regular, crystallization occurs during the preparation of the sheet, so the sheet also has good tensile performance.

[0021] According to some preferred embodiments of the present application, the random copolymer polypropylene x has: a melting point of 110-150°C, preferably 120-140°C; and / or, a melt flow rate at 230°C under a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, further preferably 3-18 g / 10 min; and / or, a molecular weight distribution Mw / Mn of 5-12, preferably 7-10; and / or, is a copolymer of propylene and ethylene and / or butene, preferably an ethylene-propylene-butene terpolymer and / or a propylene-ethylene binary copolymer.

[0022] According to some preferred embodiments of the present application, the thermal bonding enhancer y has: a melting point or viscous flow temperature of 50-110°C; and / or, a melt flow rate at 190°C under a load of 2.16 kg of 0.5-50 g / 10 min, preferably 1-20 g / 10 min, further preferably 1-18 g / 10 min; and / or, is selected from one or more of polyolefin elastomer, ethylene-propylene-diene rubber, SEBS (hydrogenated styrene-butadiene block copolymer), SBS (styrene thermoplastic elastomer), EVA, petroleum resin; preferably, is polyolefin elastomer and / or petroleum resin.

[0023] According to some preferred embodiments of the present application, the polyolefin elastomer is a copolymer elastomer of ethylene and propylene and / or an alpha olefin, preferably a C4-C12 alpha 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.

[0024] According to the present application, since the foamed material is a polyolefin thermoplastic elastomer, the thermal adhesion enhancer y is particularly preferably a polyolefin elastomer.

[0025] According to the present inventors' research, when the melt mass flow rate and the polymer composition ratio of the polypropylene composition B, the polypropylene composition B' are within the preferred ranges, the low-melting random copolymer polypropylene x and the thermal adhesion enhancer y in the composition can significantly reduce the hot-pressing temperature and broaden the hot-pressing temperature window, and the thermal adhesion enhancer y provides good adhesion properties for the sheet, which can further improve the interlayer peeling strength.

[0026] According to the present inventors' research, when the melt mass flow rate, the polymer composition ratio and the thickness distribution of layer A of the polypropylene composition A, the polypropylene composition B, the polypropylene composition B' are within the preferred ranges, the sheet preparation process can be more stable, so that the sheet has better uniformity, tensile strength, impact performance and interlayer peeling strength.

[0027] According to some preferred embodiments of the present application, the layer A further contains a β crystal nucleating agent; preferably, the β crystal nucleating agent is selected from at least one of the following: a fused ring aromatic hydrocarbon type, a Group ⅡA two-component complex type, an aromatic diamide type, a rare earth compound type and a cyclic dicarboxylate type nucleating agent.

[0028] According to some preferred embodiments of the present application, the content of the β crystal nucleating agent in the layer A is 0.01-0.5 parts by weight with respect to 100 parts by weight of the polypropylene composition A. For example, it can be 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 parts by weight, and any two values or any interval of any two values.

[0029] According to the present inventors' research, when the melt mass flow rate, the polymer composition ratio and the thickness distribution of layer A of the polypropylene composition A and the polypropylene composition B, B' are within the preferred ranges, the composite material preparation process can be more stable, so that the composite material has better uniformity, tensile strength, impact performance and interlayer peeling strength.

[0030] The BAB' sheet structure of the polypropylene sheet can be prepared by various methods. In a preferred embodiment of the present application, the BAB' sheet structure of the polypropylene sheet is prepared by co-extruding the components including the polypropylene composition A and the polypropylene composition B, B'.

[0031] According to some preferred embodiments of the present application, the melting point of the homopolymer polypropylene a in the polypropylene composition A is greater than the melting point of the random copolymer polypropylene x in the polypropylene composition B, B', preferably the temperature difference of the corresponding melting points is greater than or equal to 10 degrees. In this preferred embodiment, the inventors of the present application have surprisingly found that the obtained polypropylene sheet laminated thermoplastic elastomer composition foamed sheet hot-pressed, etc. obtains a multi-layer reinforced composite thermoplastic elastomer foamed sheet, which has more excellent mechanical properties, and at the same time has better interlayer peeling strength, even at lower hot-pressing temperatures and a wider hot-pressing temperature range, the obtained multi-layer reinforced composite thermoplastic elastomer foamed sheet has higher interlayer peeling strength.

[0032] The polypropylene fabric in the present application is obtained by weaving the polypropylene sheet described above; preferably, the polypropylene fabric has a three-dimensional structure of plain weave, twill weave and / or satin weave.

[0033] In order to facilitate weaving, the polypropylene sheet is preferably cut into a polypropylene sheet with a width of 2-5 mm, and then woven into a polypropylene fabric.

[0034] In a more preferred embodiment of the present application, the polypropylene fabric is a three-layer co-extruded polypropylene stretched flat tape woven plain weave, twill weave, satin weave or three-dimensional polypropylene fabric. In a more preferred embodiment of the present application, the polypropylene fabric is a three-layer co-extruded polypropylene stretched flat tape woven plain weave, twill weave, satin weave or three-dimensional polypropylene fabric, and the three-layer co-extruded polypropylene stretched flat tape includes at least one layer A formed by the high-melting-point polypropylene composition A and at least one layer B formed by the low-melting-point polypropylene composition B, wherein the polypropylene composition A includes the homopolymer polypropylene a and the impact copolymer polypropylene b; the polypropylene composition B includes the random copolymer polypropylene x and the thermal bonding enhancement enhancer y, and the polymeric film B layer is located on both sides of the A layer.

[0035] According to some preferred embodiments of the present application, each layer of the reinforced composite sheet comprises a plurality of sequentially stacked polypropylene sheet layer unit groups; each polypropylene sheet layer unit group comprises at least one same or different polypropylene sheet layer unit, each polypropylene sheet layer unit comprises a core layer A i and outer layers B i , B' i , B' i , B iA i B' i ; the structure of the reinforced composite sheet is sequentially from bottom to top: the nth group, the (i-1)th group, the 2nd group, the 1st group, the 2nd group, the (i+1)th group, the nth group, and the total number of the stacked polypropylene sheet layer unit groups is 2n-1; i and n are each an integer not less than 2, and i≤n; wherein the core layer A i contains the polypropylene composition A i , the outer layer B i is the same as or different from the outer layer B' i , and each corresponds to containing the polypropylene composition B i , the polypropylene composition B' i ; the melting point of the polypropylene composition A i is greater than the melting point of the polypropylene composition B i , and the melting point of the polypropylene composition B' i ; the average value of the melting points of all the outer layers in the ith group is greater than or equal to the average value of the melting points of all the outer layers in the (i-1)th group.

[0036] More preferably, the difference between the melting point of the polypropylene composition A i and the melting point of the polypropylene composition B i , and the difference between the melting point of the polypropylene composition A i and the melting point of the polypropylene composition B' i are each greater than or equal to 5℃, preferably greater than or equal to 10℃, and more preferably greater than or equal to 20℃.

[0037] According to the present application, preferably, the total number of the stacked polypropylene sheet layer unit groups is 2n-1, and the present application has a wide selection range for the total number of the stacked polypropylene sheet layer unit groups, in a preferred embodiment of the present application, 2≤n≤100 is selected, more preferably 2≤n≤50, and further preferably 2≤n≤30.

[0038] According to the present application, the number of the polypropylene sheet layer units included in each polypropylene sheet layer unit group has a wide selection range, in a preferred embodiment of the present application, each polypropylene sheet layer unit group, independently, includes 1 to 10, preferably 1 to 5, more preferably 1 to 3, same or different polypropylene sheet layer units, and more preferably 1 polypropylene sheet layer unit. Preferably, the number of the polypropylene sheet layer units included in each polypropylene sheet layer unit group is the same.

[0039] Preferably but not necessarily, the melting point of any outer layer in each group is within ±10℃, preferably within ±5℃, more preferably within ±3℃, and further preferably within ±1℃ of the average value of the melting points of all the outer layers in the group.

[0040] In the embodiment in which each polypropylene sheet layer unit group comprises only 1 polypropylene sheet layer unit, for example, the structure of the polypropylene composite material can be in turn from bottom to top 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 of the polypropylene sheet layer units is 2n-1; i, n are both integers not less than 2, and i≤n.

[0041] In the embodiment in which each polypropylene sheet layer unit group comprises 2 or more polypropylene sheet layer units, for example, the structure of the ith polypropylene sheet layer 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 in turn from bottom to top (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 A12 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 layers of the polypropylene sheet layer units is j+2k+...2p+...2q; j, k, p, q, each independently, is an integer not less than 2, preferably 2 to 10, more preferably 2 to 5, more preferably 2 to 3.

[0042] According to some preferred embodiments of the present application, the multi-layer reinforced composite foamed sheet has a multi-layer sandwich structure, i.e. arranged in the structure of reinforced composite sheet, plastic elastomer composition foamed sheet, reinforced composite sheet, plastic elastomer composition foamed sheet,... reinforced composite sheet. When hot pressing, the upper and lower pressing plates can not be heated, and the entire part that needs to be hot pressed is placed in an oven, and hot pressing can be achieved as long as the hot melting temperature of the thermoplastic elastomer composition foamed material is reached.

[0043] According to some preferred embodiments of the present application, the total thickness of the reinforcing composite sheet accounts for 1.3%-15.5% of the total thickness of the multi-layer reinforced composite foamed sheet, and the inventors of the present application have found that, within this preferred range, the multi-layer foamed sheet is easier to be hot-pressed together, the interlayer peeling strength is higher, and meanwhile, the multi-layer reinforced composite foamed sheet has both high resilience (i.e. falling weight impact strength) and tensile strength that can meet the application requirements. More preferably, the total thickness of the reinforcing composite sheet accounts for 4%-15.5% of the total thickness of the multi-layer reinforced composite foamed sheet. In this more preferred embodiment, the obtained multi-layer reinforced composite foamed sheet has higher tensile strength and high resilience (i.e. falling weight impact strength), and has better comprehensive performance.

[0044] According to some preferred embodiments of the present application, the thickness of the thermoplastic elastomer composition foamed sheet is selected within a wide range, and preferably, the thickness of the thermoplastic elastomer composition foamed sheet is 4.5-60 mm, preferably 5-60 mm. In this preferred embodiment, the multi-layer foamed sheet is easier to be hot-pressed together, the interlayer peeling strength is higher, and meanwhile, the multi-layer reinforced composite foamed sheet has both high resilience (i.e. falling weight impact strength) and tensile strength that can meet the application requirements.

[0045] In the following examples, the total thickness of the thermoplastic elastomer composition foamed sheet in the multi-layer reinforced composite foamed sheet is the thickness of the multi-layer reinforced composite foamed sheet minus the thickness of all the reinforcing composite sheets, wherein the thickness of the reinforcing composite sheet (i.e. the thickness of the laminated sheet) does not change in hot-pressing and is a fixed value. For example, in Example 1, the thickness of the reinforcing composite sheet is 0.8 mm.

[0046] According to some preferred embodiments of the present application, the number of layers of the laminated reinforcing composite sheet and thermoplastic elastomer composition foamed sheet is greater than or equal to 3, preferably 3-100, more preferably 6-60.

[0047] According to some preferred embodiments of the present application, the thermoplastic elastomer composition foamed sheet is sequentially laminated from top to bottom at an angle of 0-90° along the respective machine direction, and preferably, the number of layers is greater than or equal to 1, more preferably 1-10, most preferably 2-5.

[0048] According to some preferred embodiments of the present application, the reinforcing composite sheet is sequentially laminated from top to bottom at an angle of 0-90° along the respective machine direction, and preferably, the total number of layers of the polypropylene sheet and the polypropylene fabric in each reinforcing composite sheet is greater than or equal to 2, more preferably 2-100, most preferably 4-40.

[0049] According to some preferred embodiments of the present application, the density of the foamed sheet of the thermoplastic elastomer composition is 0.01-0.5 g / L, preferably 0.1-0.4 g / L.

[0050] According to the present application, the foamed sheet of the thermoplastic elastomer composition contains a polyolefin thermoplastic elastomer composition, preferably, the polyolefin thermoplastic elastomer composition contains POE and EVA and optional additives.

[0051] As a preferred embodiment of the foamed sheet of the polyolefin thermoplastic elastomer composition provided by the present application, the preparation method of the foamed sheet comprises: adding a foaming agent to the polyolefin thermoplastic elastomer composition to foam into a foamed sheet.

[0052] Preferably, the content of the POE is 5-50 parts by weight, and the total content of the EVA is 50-95 parts by weight, based on 100 parts by weight of the total weight of the POE and the EVA.

[0053] Preferably, the additive is selected from the group consisting of a crosslinking agent, a foaming agent, stearic acid, zinc stearate, zinc oxide, a filler, and maleic anhydride copolymer microspheres.

[0054] More preferably, the content of the crosslinking agent is 0.1-1 parts by weight, preferably 0.3-0.8 parts by weight, the content of the foaming agent is 0.1-10 parts by weight, preferably 2-7 parts by weight, the content of the stearic acid is 0.1-1 parts by weight, preferably 0.2-0.5 parts by weight, the content of the zinc stearate is 0.1-1 parts by weight, preferably 0.2-0.5 parts by weight, the content of the zinc oxide is 0.1-10 parts by weight, preferably 0.5-2 parts by weight, the content of the filler is 1-40 parts by weight, preferably 5-30 parts by weight, and the content of the maleic anhydride copolymer microspheres is 0.1-5 parts by weight, preferably 0.2-1 parts by weight, based on 100 parts by weight of the total weight of the POE and the EVA.

[0055] In order to further explain the present application, preferably, the foamed sheet of the polyolefin thermoplastic elastomer composition contains the following components in parts by weight based on 100 parts by weight of the total weight of the foamed sheet of the polyolefin thermoplastic elastomer composition:

[0056] POE 5-50 parts by weight;

[0057] EVA 50-95 parts by weight;

[0058] Crosslinking agent: 0.1-1 parts by weight, preferably 0.3-0.8 parts by weight;

[0059] Foaming agent: 0.1-10 parts by weight, preferably 2-7 parts by weight;

[0060] stearic acid: 0.1-1 parts by weight, preferably 0.2-0.5 parts by weight;

[0061] zinc stearate: 0.1-1 parts by weight, preferably 0.2-0.5 parts by weight;

[0062] zinc oxide: 0.1-10 parts by weight, preferably 0.5-2 parts by weight;

[0063] filler: 1-40 parts by weight, preferably 5-30 parts by weight;

[0064] maleic anhydride copolymer microspheres: 0.1-5 parts by weight, preferably 0.2-1 parts by weight.

[0065] According to the present application, the POE can be selected from the POEs conventional in the art, preferably the POE has the following characteristics:

[0066] The comonomer is 1-butene, 1-hexene or 1-octene, and the comonomer content is 10-20 mol%. The catalyst is a CGC catalyst (complex of monocyclopentadiene and a transition metal of subgroup IV by coordination bond), a metallocene catalyst, or a salicylaldimine titanium catalyst.

[0067] In addition, preferably, the weight average relative molecular mass of the POE is 100-200,000, preferably 120-170,000, and the molecular weight distribution width is preferably 1-3, preferably 1.5-2.5.

[0068] Preferably, the mass melt flow rate of the POE is 0.1-2 g / 10 min (2.16 kg, 190°C), preferably 0.4-1.5 g / 10 min (2.16 kg, 190°C).

[0069] Preferably, the EVA has the following characteristics: the content of vinyl acetate (VA) is 5-35 mol%, measured by NMR, the NMR experiment is performed on an Agilent 400-MR DD2 nuclear magnetic resonance spectrometer, the solvent is CDC13, and the test temperature is 40°C. The mass melt flow rate is 1-10 g / 10 min (2.16 kg, 190°C), preferably 2-7 g / 10 min (2.16 kg, 190°C).

[0070] The polyolefin thermoplastic elastomer foamed sheet composition can also contain one or more of the following processing aids commonly used in the polyolefin thermoplastic elastomer foaming process, such as but not limited to:

[0071] Graphite color powder: 1% to 8%, preferably 2 to 5%; antioxidant: 0.1 to 15‰, preferably 0.1 to 5‰; antistatic agent: 0.1 to 10%, preferably 0.5 to 5%; lubricant: 0.1 to 10%, preferably 0.5 to 3%; anti-aging agent: 0.01 to 5%, preferably 0.1 to 2%; flame retardant: 0.1 to 25%, preferably 1 to 20%. The content of processing aids is well known in the industry and will not be described here.

[0072] According to the present application, the polyolefin thermoplastic elastomer composite foamed material can be adjusted in density according to requirements and specific process.

[0073] Preferably, the density of the foamed material is 0.01 to 0.5 g / L, preferably 0.1 to 0.4 g / L;

[0074] Preferably, the tensile strength stress of the foamed material should be greater than 2 MPa, preferably greater than 2.2 MPa, for example, it can be 2 to 4 MPa. (GB / T 6344-2008)

[0075] Preferably, the elongation at break of the foamed material should be greater than 250%, preferably greater than 300%, for example, it can be 250 to 400%. (GB / T 6344-2008)

[0076] Preferably, the resilience of the foamed material is greater than 50%, preferably greater than 60%, for example, it can be 50 to 80%.

[0077] The polyolefin thermoplastic elastomer composition foamed sheet used in each embodiment of the present application is within the preferred range of the density, tensile strength stress, elongation at break, and resilience of the foamed material identified above, unless otherwise specified.

[0078] The polyolefin thermoplastic elastomer composition foamed sheet of the present application is preferably molded and foamed, and preferably, the molded and foamed process includes the following steps:

[0079] (1) The molding and foaming machine is heated to 180°C and stabilized for 15 minutes;

[0080] (2) The composition is broken into particles or granulated and then added to the foaming machine;

[0081] (3) The foaming temperature is set to 180°C, the molding and foaming time is 550 s, and the back pressure is 10 MPa;

[0082] (4) After the pressure holding time is reached, the pressure is released and the mold is jumped to obtain the foamed material.

[0083] The blowing agent used in the present application can be selected from a physical blowing agent or a chemical blowing agent. The physical blowing agent can be an organic physical blowing agent or an inorganic physical blowing agent. The organic physical blowing agent includes, but is not limited to, at least one of aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane, alicyclic hydrocarbons such as cyclobutane and cyclohexane, and halogenated hydrocarbons such as chlorofluoromethane, trifluoromethane, 1,2-difluoroethane, 1,2,2,2-tetrafluoroethane, methyl chloride, ethyl chloride and dichloromethane. The inorganic physical blowing agent includes, but is not limited to, at least one of air, nitrogen, carbon dioxide, oxygen and water. The added blowing agent decomposes to release gas at a specific temperature and pressure, forming a porous bubble structure in the resin and the like. The most commonly used chemical blowing agent is an organic chemical blowing agent, which specifically includes azodicarbonamide (AC), azobisisobutyronitrile (AIBN), barium azodicarboxylate (BaAC) and azodicarboxylate, dinitrosopentamethylene tetramine (DPT), N,N'-dinitrosopentamethylene tetramine, N,N'-dimethyl-N,N-dinitrosophthaloyl diamide (NTA) and trinitrosotrimethylenetriamine, 4,4'-oxobisbenzenesulfonyl hydrazide (OBSH), toluenesulfonyl amino urea (TSSC), triphosphoryl triazine (CTHT), 5-phenyl tetrazole, 2,4-toluene disulfonyl hydrazide, p-toluenesulfonyl hydrazide and the like.

[0084] The antioxidant can be any antioxidant conventionally used in the art. Preferably, the antioxidant is a mixture of a hindered phenolic antioxidant and a phosphite antioxidant at a mass ratio of 1:3 to 3:1; wherein the hindered phenolic antioxidant can be selected from at least one of antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester; CAS No.: 6683-19-8), 3114 (1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; CAS: 27676-62-6) or 330 (1,3,5-trimethyl-2,4,6-tris(3,5-tert-butyl-4-hydroxybenzyl)benzene; CAS: 1709-70-2); and the phosphite antioxidant can be selected from at least one of antioxidant 168 (tris[2.4-di-tert-butylphenyl]phosphite; CAS: 31570-04-4), antioxidant 618 (distearyl pentaerythritol diphosphite; CAS: 3806-34-6) or antioxidant 2,2'-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite; CAS: 118337-09-0).

[0085] The crosslinking agent is mainly selected from organic peroxide, dicumyl peroxide, peroxyneohexanoic acid, 1-dimethyl-3-hydroxybutyl peroxide, peroxyneodecanoic acid, tert-pentyl perbenzoate, tert-butyl perbenzoate, tert-pentyl peroctoate, tert-butyl peroctoate, bis-tert-butyl peroxide dicumyl, triallyl isocyanurate.

[0086] The filler is preferably selected from the group consisting of inorganic powders such as talc, kaolin, calcium carbonate, borax, zinc borate, aluminum hydroxide and silicon dioxide, and polymers such as polytetrafluoroethylene, polyethylene wax, polycarbonate, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexane dimethylene terephthalate, polyethylene adipate, polybutylene adipate, silicone, methyl methacrylate copolymer and crosslinked polystyrene. Inorganic powders are preferred, and talc is particularly preferred.

[0087] According to some more preferred embodiments of the present application, the polyolefin thermoplastic elastomer foamed sheet composition contains maleic anhydride copolymer microspheres. The inventors of the present application have found that the maleic anhydride copolymer microspheres can act as a compatible dispersant to improve the compatibility between the components in the polyolefin thermoplastic elastomer composition.

[0088] In the present application, the particle size of the maleic anhydride copolymer microspheres is 1000-1600 nm, preferably 1000-1500 nm.

[0089] In the present application, the average particle size of the copolymer microspheres is measured by scanning electron microscopy (SEM).

[0090] In the present application, the copolymer in the maleic anhydride copolymer microspheres contains structural unit A provided by maleic anhydride and structural unit B provided by α-methylstyrene, and the molar content of the structural unit A is 46-53% and the molar content of the structural unit B is 47-54% based on the total molar amount of each structural unit in the copolymer.

[0091] In the present application, the total amount of substance of the structural unit A provided by maleic anhydride and the structural unit B provided by α-methylstyrene is 100%.

[0092] In the present application, the molar content of each structural unit in the copolymer is tested by 1H NMR, and the testing method is calculated by the proportion of the peak area of the characteristic hydrogen in the corresponding structural unit in 1H NMR.

[0093] In the present application, when the maleic anhydride copolymer contains the above-mentioned specific molar content of the structural units, it can make the maleic anhydride copolymer have microspheres with good uniformity, and the copolymer has a clean surface and good dispersibility in the medium without aggregation.

[0094] Further, in order to obtain a maleic anhydride copolymer with more excellent comprehensive performance, the molar content of the structural unit A is 48%-52% and the molar content of the structural unit B is 49%-51% based on the total molar amount of each structural unit in the copolymer.

[0095] In the present application, the maleic anhydride copolymer microspheres are prepared according to the following steps:

[0096] S1, dissolving the polymer monomer and the initiator in a reaction medium to form a homogeneous solution in an inert atmosphere;

[0097] S2, after the homogeneous solution is subjected to a polymerization reaction to obtain a copolymer emulsion, and after solid-liquid separation, the maleic anhydride copolymer is obtained;

[0098] The polymer monomer is maleic anhydride and α-methylstyrene; the amount of the maleic anhydride is 29-63 wt% based on the total weight of the polymer monomer, and the amount of the α-methylstyrene is 36-72 wt%.

[0099] The reaction medium is a mixture of compound I represented by formula (1) and compound II represented by formula (2);

[0100]

[0101] R1 and R2 are each independently an alkyl group with a carbon atom number of 1 to 3; R3, R4 and R5 are each independently H, methyl or ethyl.

[0102] In the present application, maleic anhydride and α-methylstyrene are copolymerized in a specific ratio in the presence of a specific reaction medium, so that the prepared maleic anhydride copolymer is in the form of a microsphere with excellent uniformity, and the copolymer has the characteristics of a clean surface, good dispersibility in the medium and no aggregation, and the prepared maleic anhydride copolymer has no special odor.

[0103] Further, in order to obtain maleic anhydride copolymer microspheres with more uniform particles and more excellent morphology, the inventors have studied the amount of maleic anhydride and α-methylstyrene in the polymerization process, and the research shows that when the amount of the maleic anhydride is 40-50 wt% and the amount of the α-methylstyrene is 45-55 wt% based on the total weight of the polymer monomer, the prepared maleic anhydride copolymer is in the form of a spherical particle with more uniform particles and more excellent morphology, and the comprehensive performance of the copolymer is more excellent.

[0104] In the present application, the mass concentration of the polymer monomer is 5-25 wt% based on the total weight of the homogeneous solution, preferably 5-20 wt%.

[0105] In the present application, the initiator is an organic peroxide and / or an azo compound.

[0106] In the present application, the organic peroxide is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, dilauryl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

[0107] In the present application, the azo compound is selected from azobis isobutyronitrile and / or azobis isoheptyl nitrile.

[0108] In the present application, the mass concentration of the initiator is 0.2-3.1wt%, preferably 1-2wt%, based on the total weight of the homogeneous solution.

[0109] In the present application, the mixture of compound I represented by formula (1) and compound II represented by formula (2) is selected as the reaction medium, which can cooperate with the specific amount of maleic anhydride and alpha-methyl styrene described in the present application, and can realize the self-stable precipitation polymerization of maleic anhydride and alpha-methyl styrene. In the polymerization system, no stabilizer and co-stabilizer is needed, and has a self-stable dispersion effect, and the obtained polymer microspheres have clean and non-polluted surface.

[0110] Further, in formula (3), R1 and R2 are each independently methyl or ethyl.

[0111] Further, in formula (3), R3, R4 and R5 are each independently methyl or ethyl.

[0112] In the present application, the amount of compound II is 50-90vol%, based on the total volume of the reaction medium.

[0113] In the present application, when the amounts of compound I and compound II in the reaction medium meet the above range, a maleic anhydride copolymer with more excellent polymer microsphere morphology can be obtained. Further, when the amount of compound II is 60-90vol%, based on the total volume of the reaction medium, the effect is more excellent.

[0114] In the present application, the conditions of the polymerization reaction include: the polymerization temperature is 60-90℃, preferably 70-80℃; the polymerization time is 1-24h, preferably 3-12h.

[0115] In the present application, a water bath and / or an oil bath are used to provide the heat required for the polymerization.

[0116] In the present application, the solid-liquid separation can be a conventional solid-liquid separation method in the art, such as centrifugal separation.

[0117] In the present application, when centrifugal separation is used, the rotation speed of centrifugation is 1000-4000rad / min, and the centrifugation time is 10-40min.

[0118] The mechanical strength and thermal insulation performance of the composite foamed sheet are compared with those of a non-reinforced sheet composite foamed sheet prepared by the same process. The tensile strength is increased, the elongation at break is increased, and the thermal conductivity is increased by no more than 15%, preferably by no more than 10%. Compared with other reinforced composite sheets (glass fiber reinforced sheets), the mechanical strength is increased, the elongation at break is increased, and the thermal conductivity is reduced by 15%, preferably by 30%. Test method: The thermal conductivity is determined according to the method specified in GB / T 10294.

[0119] According to the present application, preferably, the multi-layer reinforced composite foamed sheet is prepared by the following method: the polypropylene sheet and / or the polypropylene fabric is laminated with the thermoplastic elastomer composition foamed sheet, fused by hot pressing, and then shaped by cooling to obtain the multi-layer reinforced composite foamed sheet (referred to as method one); or, the polypropylene sheet and / or the polypropylene fabric is first laminated and arranged, fused by hot pressing to obtain a reinforced composite sheet; then the reinforced composite sheet is laminated and arranged with the thermoplastic elastomer composition foamed sheet, fused at 60-80°C to obtain the multi-layer reinforced composite foamed sheet (referred to as method two).

[0120] According to the present application, the thermoplastic elastomer composition foamed sheet preferably has a number of layers greater than or equal to 1, more preferably 1-10 layers, and most preferably 2-5 layers. The preparation method of the multi-layer reinforced composite foamed sheet can be flexibly selected according to the number of layers of the thermoplastic elastomer composition foamed sheet in the target product. For example, the polypropylene sheet and / or the polypropylene fabric can be laminated with the thermoplastic elastomer composition foamed sheet, fused by hot pressing, and then shaped by cooling to obtain the multi-layer reinforced composite foamed sheet, i.e., one hot pressing fusion is performed to obtain the multi-layer reinforced composite foamed sheet; or the polypropylene sheet and / or the polypropylene fabric can be first prepared into a reinforced composite sheet by hot pressing fusion, and then the reinforced composite sheet is laminated and arranged with the thermoplastic elastomer composition foamed sheet, fused at 60-80°C, and the hot pressing pressure is 3.5-7 MPa, more preferably, the pressure increases with the increase of the number of intercalated sheets, to obtain the multi-layer reinforced composite foamed sheet.

[0121] Method two is suitable for all cases where the effects of the present application are achieved, i.e., when the thermoplastic elastomer composition foamed sheet preferably has a number of layers greater than or equal to 1, more preferably 1-10 layers, and most preferably 2-5 layers, method two can be used for preparation.

[0122] Preferably, when the thermoplastic elastomer composition foamed sheet preferably has a number of layers equal to 1, method one can be used for preparation, i.e., prepared by one hot pressing fusion.

[0123] The second aspect of the present application is to provide a method for preparing the multi-layer reinforced composite foamed sheet material of the first aspect, comprising: stacking the polypropylene sheet material and / or the polypropylene fabric with the thermoplastic elastomer foamed sheet material, fusing by hot pressing, and then cooling and setting to obtain the multi-layer reinforced composite foamed sheet material (referred to as method one); or, first stacking the polypropylene sheet material and / or the polypropylene fabric, fusing by hot pressing to obtain a reinforced composite sheet material; then stacking the reinforced composite sheet material with the thermoplastic elastomer foamed sheet material, fusing at 60-80°C to obtain the multi-layer reinforced composite foamed sheet material (referred to as method two).

[0124] According to the present application, preferably, the polypropylene sheet material and / or the polypropylene fabric are stacked in the order of forming the corresponding layer of the reinforced composite sheet material.

[0125] The hot pressing fusing conditions in method one and method two can be the same or different. In a preferred embodiment of the present application, the hot pressing fusing temperature is 115-170°C, preferably 115-159°C, and further preferably 140-159°C.

[0126] In a preferred embodiment of the present application, the hot pressing fusing pressure is 2-10 MPa.

[0127] In a preferred embodiment of the present application, the hot pressing fusing preheating time is 5-600 s, and the hot pressing time is 1-600 s, preferably 10-500 s.

[0128] In a preferred embodiment of the present application, the cooling and setting pressure is 2-8 MPa, and the cooling and setting time is 30 s-700 s.

[0129] In a preferred embodiment of the present application, the number of layers of the stacked polypropylene sheet material and / or polypropylene fabric and the polyolefin elastomer foamed sheet material is greater than or equal to 3 layers, preferably 3-100 layers, and more preferably 6-60 layers.

[0130] In a preferred embodiment of the present application, the adjacent layers of the stacked polypropylene sheet material are placed at 0-90° along the respective machine direction, i.e. the stretching direction (MD).

[0131] In a preferred embodiment of the present application, the adjacent layers of the stacked polypropylene fabric are placed at 0-90° between the warp direction and the weft direction.

[0132] According to some preferred embodiments of the present application, the hot pressing fusing conditions include:

[0133] hot-pressing temperature 115-170°C, preferably 115-159°C, further preferably 140-159°C; and / or, hot-pressing pressure 2-10 MPa, preheating time 5-600 s, hot-pressing time 1-600 s, preferably 10-500 s; and / or, cooling pressure 2-8 MPa, cooling time 30-700 s.

[0134] In a more preferred embodiment of the present application, the method for preparing the multi-layer reinforced composite foamed sheet comprises the following steps:

[0135] Step a: co-extruding polypropylene composition A, polypropylene composition B, polypropylene composition B' in the structure of BAB' and then casting or calendering to obtain a polypropylene co-extruded sheet; preferably, the temperature for extrusion casting or calendering is 200-240°C, and the temperature of the calendering roller is 50-70°C;

[0136] Step b: stretching the polypropylene co-extruded sheet at a certain temperature to obtain a polypropylene stretched sheet; the stretching method is free stretching, and / or solid-phase stretching, and / or multi-stage stretching; preferably, the temperature for stretching is 90-165°C, preferably 90-140°C, further preferably 90-119°C; the stretching ratio is 1-20 times, preferably 2-15 times.

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

[0138] Step d: after each component of POE, EVA, crosslinking agent, foaming agent, stearic acid and zinc stearate is metered according to the formula, it is added into a high-speed stirrer, continuously stirred at high speed at room temperature for 1-10 min, preferably 2-5 min, then enters a banbury mixer, the banbury temperature is 100-110°C, and the banbury time is 9-11 min, for example 10 min, then forcedly added into a twin-screw extruder, extruded at 150-180°C, and granulated to obtain polyolefin thermoplastic elastomer composition particles.

[0139] Step e: polyolefin elastomer foam material preparation, the mold installed between the molding machine is heated to the foaming temperature of 130-200 °C, preferably 170-190 °C, stable for 10-20 minutes, for example 15 minutes; the polyolefin thermoplastic elastomer composition particles of step d are put into it, the molding machine is closed, and the mold is sealed. The gas generated by the foaming agent diffuses into the polyolefin thermoplastic elastomer composition resin particles, the foaming temperature is set to 170-185 °C, for example 180 °C, the molding foaming time is 500-600 s, for example 550 s, and the back pressure is 9-12 MPa, for example 10 MPa; after the pressure holding time is reached, the pressure is released and the mold is opened to obtain the foamed material. Cutting again to obtain the desired thickness of the polyolefin thermoplastic elastomer composition foam sheet.

[0140] Step f: the polypropylene fabric and the foam sheet prepared in step e are sequentially laminated and hot-pressed to fuse, and then cooled and shaped to form a multi-layer reinforced composite foam sheet; preferably in step f, the hot-pressing conditions are: hot-pressing temperature 115-170 °C, preferably 115-159 °C, and further preferably 140-159 °C; hot-pressing pressure 2-10 MPa, preheating time 5-600 s, hot-pressing time 1-600 s, preferably 10-500 s, cooling pressure 2-8 MPa, and cooling time 30 s-700 s; preferably the adjacent polypropylene fabrics in the multi-layer reinforced composite foam sheet can be placed at an angle of 0-90° between the warp and the warp. A thermal adhesion enhancer is used between each layer of hot-pressed material, and the thermal adhesion enhancer preferably used between the polyolefin thermoplastic elastomer foam material and the polypropylene laminated material is a polyolefin elastomer (POE).

[0141] According to some embodiments of the present application, in step c, a high-speed slitting machine with multiple blades can be used for cutting to obtain oriented polypropylene flat tapes with a width of 2-5 mm; a commercial weaving machine is used to weave the oriented flat tapes according to the designed fabric structure to obtain plain, twill, satin or other three-dimensional polypropylene fabrics.

[0142] According to the present application, in a preferred specific embodiment, the pressure is preferably continuously maintained during the hot-pressing and cooling processes, and does not decrease; the hot-pressing process is continuous, and a continuous hot-pressing composite material forming equipment consisting of a preheating machine, a continuous track-type flat hot-pressing machine, a continuous track-type flat cooling press, a sheet cutting machine and a sheet stacking machine arranged in sequence is preferably used; preferably, the continuous track-type flat hot-pressing machine has a preheating unit, an independent heating and pressing unit, an air cooling unit and a lifting mechanism.

[0143] In the preparation, the polypropylene sheet and / or the polypropylene fabric and the polyolefin thermoplastic elastomer composition foamed sheet are sequentially stacked and preheated by a preheating machine, the preheated sample is sequentially hot-pressed and fused by a track-type plane hot press, and then cooled and shaped by a track-type continuous plane cooling press to form a polyolefin thermoplastic elastomer composition foamed sheet / polypropylene composite sheet (i.e., a multi-layer reinforced composite foamed sheet), i.e., a stacked hot-pressed product (a multi-layer sandwich structure). Then, the hot-pressed product is stacked and arranged by a sheet stacking machine according to needs after being cut by a sheet cutting machine. The hot-pressing temperature is controlled by a preheating unit, an independent heating and pressurizing unit and an air cooling unit in the track-type plane hot press, and the hot-pressing pressure is controlled by a lifting mechanism. It has been found by the inventors that the polyolefin thermoplastic elastomer composition foamed sheet / polypropylene composite sheet prepared by using the preparation equipment has better tensile strength, impact performance and interlayer peeling strength when the preparation process parameters are within the preferred range.

[0144] According to the present application, the number of layers of the thermoplastic elastomer composition foamed sheet is preferably greater than or equal to 1, more preferably 1-10, and most preferably 2-5. The preparation method of the multi-layer reinforced composite foamed sheet can be flexibly selected according to the number of layers of the thermoplastic elastomer composition foamed sheet in the target product. For example, the polypropylene sheet and / or the polypropylene fabric can be stacked with the thermoplastic elastomer composition foamed sheet, hot-pressed and fused, and then cooled and shaped to obtain the multi-layer reinforced composite foamed sheet, i.e., the multi-layer reinforced composite foamed sheet is obtained by one-time hot-pressing and fusing. Alternatively, the polypropylene sheet and / or the polypropylene fabric can be prepared into a reinforced composite sheet by hot-pressing and fusing, and then the reinforced composite sheet can be stacked with the thermoplastic elastomer composition foamed sheet and fused at 60-80°C to obtain the multi-layer reinforced composite foamed sheet.

[0145] Method two is suitable for all cases where the effects of the present application are achieved, i.e., when the number of layers of the thermoplastic elastomer composition foamed sheet is preferably greater than or equal to 1, more preferably 1-10, and most preferably 2-5, method two can be used for preparation.

[0146] Preferably, when the number of layers of the thermoplastic elastomer composition foamed sheet is equal to 1, method one can be used for preparation, i.e., the multi-layer reinforced composite foamed sheet is obtained by one-time hot-pressing and fusing.

[0147] According to the present application, in method two, the temperature for fusing the reinforced composite sheet with the thermoplastic elastomer composition foamed sheet is 60-80°C, which is close to the surface softening temperature of the POE elastomer.

[0148] Preferably, the process of fusing the reinforced composite sheet with the thermoplastic elastomer composition foamed sheet in the second method is carried out in an oven containing a platen, the oven has a volume larger than the multi-layer reinforced composite foamed sheet, the platen is placed above the uppermost layer of the reinforced composite sheet, the hot pressing temperature is close to the surface softening temperature of the POE elastomer, the POE elastomer surface is softened, and then the reinforced composite sheet is fused with the thermoplastic elastomer composition foamed sheet.

[0149] The time for fusing the reinforced composite sheet with the thermoplastic elastomer composition foamed sheet can be selected within a wide range, as long as the thermoplastic elastomer composition foamed sheet is softened to achieve the thermoplastic elastomer composition foamed sheet bonding the reinforced composite sheet together. For example, in the embodiment of the present application, the reinforced composite sheet and the polyolefin elastomer composition reach 70°C, and then the temperature is kept constant for 5 minutes to soften the thermoplastic elastomer composition foamed sheet, and hot pressing for 30 seconds can complete the molding. Preferably, the temperature is kept constant at 60-80°C for 2-10 minutes, and then hot pressing for 20-100 seconds.

[0150] The pressure for fusing the reinforced composite sheet with the thermoplastic elastomer composition foamed sheet can be selected within a wide range in the present application. Preferably, the pressure for fusing the reinforced composite sheet with the thermoplastic elastomer composition foamed sheet is 3.5-7 MPa.

[0151] The third aspect of the present application is to provide the application of the multi-layer reinforced composite foamed sheet of the first aspect or the multi-layer reinforced composite foamed sheet prepared by the preparation method of the second aspect in the fields of automobiles, communications, airplanes, logistics, thermal insulation, precision machinery and electronic turnover, and packaging.

[0152] Compared with the prior art, the present application has the following beneficial effects:

[0153] (1) The composite foamed sheet provided by the present application composites a high-strength high-impact polypropylene sheet with a polyolefin thermoplastic elastomer composition foamed sheet. It has good tensile strength, impact performance and interlayer peeling strength; the multi-layer reinforced composite foamed sheet has the following characteristics:

[0154] The longitudinal (MD) tensile strength is ≥ 4 MPa, preferably ≥ 10 MPa; the interlayer peeling strength is ≥ 0.85 N / mm, preferably ≥ 0.9 N / mm; the falling weight impact strength is ≥ 69 J, preferably ≥ 78 J when the multilayer reinforced composite foamed sheet is prepared by hot pressing only 10 layers of polypropylene fabric and 1 layer of polyolefin thermoplastic elastomer composition foamed sheet, and the thickness is about 5.5 mm. Compared with the composite foamed sheet prepared by the same process without reinforcement, the mechanical strength and thermal insulation performance of the composite foamed sheet are improved, the tensile strength is increased, the thermal conductivity is increased by not more than 15%, preferably not more than 10%, compared with other reinforced composite sheets (glass fiber reinforced sheets), the mechanical strength is increased, the elongation at break is increased, and the thermal conductivity is reduced by 15%, preferably reduced by 30%. Test method: the thermal conductivity is determined according to the method specified in GB / T 10294.

[0155] (2) Compared with the commonly used glass fiber nylon (polypropylene) composite preformed sheet or metal sheet reinforced molding body for the composite reinforced polyolefin thermoplastic elastomer composition foamed sheet, the compatibility between the preformed sheet and the base resin is greatly improved, which can effectively reduce the apparent density and thermal conductivity of the product.

[0156] (3) The polyolefin thermoplastic elastomer composition foamed sheet of the present application can be prepared by the existing mold foaming molding process, which is simple and low in production cost.

[0157] (4) The polypropylene composite foamed sheet of the present application is a uniform polymer component, which does not need to be separated and treated during recycling, and can be directly used in other processing application fields after crushing, melting and granulation. In particular, since the recycled material contains polyolefin thermoplastic elastomer composition, the mechanical properties of the recycled material can be maintained to the greatest extent, and the recycled material has a prospect of secondary processing and molding.

[0158] Other features and advantages of the present application will be described in detail in the following specific embodiments. DETAILED DESCRIPTION

[0159] The present application will be described in detail below with specific examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present application still fall within the protection scope of the present application.

[0160] The present application will be described in detail below with specific examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present application still fall within the protection scope of the present application.

[0161] In the following examples and comparative examples:

[0162] The extrusion calender and solid phase drawing equipment were purchased from Tianjin Hengrui Company, model HRPC-800 three-layer co-extrusion plastic drawing sheet production line.

[0163] The properties of the polypropylene, polyolefin thermoplastic elastomer composition foamed material and composite sheet were tested according to the following methods:

[0164] The test results of the composite sheet are shown in Table 1:

[0165] (1) Melt mass flow rate (MFR): determined according to the method specified in GB / T 3682, wherein the test temperature is 230℃ and the load is 2.16kg;

[0166] (2) Density: determined according to the method specified in GB / T 1033.1 and GB / T 6343;

[0167] (3) Melting point: determined according to the method specified in GB / T 28724;

[0168] (4) Tensile strength: determined according to the method specified in GB / T 1040.1;

[0169] (5) Falling weight impact strength: determined according to the method specified in GB / T 14153;

[0170] (6) Interlayer peeling strength: sample preparation and determination were carried out according to the method specified in GB / T 3903.39-2019.

[0171] (7) Test method for thermal insulation capacity of the composite foamed sheet: thermal conductivity was determined according to the method specified in GB / T 10294.

[0172] In the following examples, the β crystal form nucleating agent with the trade name VP101B was sourced from the Beijing Research Institute of Chemical Industry; the sources of some raw materials are described in the examples, and the remaining raw materials, if not specifically stated, are commercially available.

[0173] Raw materials:

[0174] Polypropylene: Beijing Research Institute of Chemical Industry (North China Institute of Chemical Technology);

[0175] Polyolefin thermoplastic elastomer (POE): 1-butene as comonomer, POE-B, comonomer content 13.6mol%, weight average molecular mass; 1-hexene as comonomer, POE-H, comonomer content 13.1mol%; 1-octene as comonomer, POE-O, comonomer content 13.8mol%; Beijing Research Institute of Chemical Industry (North China Institute of Chemical Technology);

[0176] EVA: 5110 and 6100, BASF Yangzi; 2806, Sinopec Yancheng Research Institute of Catalysts.

[0177] Chemical foaming agent: 4,4'-oxybisbenzenesulfonylhydrazide, Inokai Technology;

[0178] Peroxide: di-tert-butyl peroxydiisopropylbenzene, Inokai Technology. Maleic anhydride copolymer microspheres, Beijing Research Institute of Chemical Industry (BRIC); Preparation Example A is used to illustrate the preparation of the compatible dispersant maleic anhydride copolymer microspheres of the present application.

[0179] Preparation Example A1

[0180] 4.9 g of maleic anhydride, 0.9 g of azobisisobutyronitrile, 6 g of α-methylstyrene, 40 ml of acetone and 60 ml of toluene were added into a 500 mL three-necked flask. After the mixture was uniformly mixed, nitrogen was passed for 20 minutes. The three-necked flask was moved into a 80°C water bath, and the reaction was carried out for 24 h. After the reaction was completed, the obtained polymer emulsion suspension was separated by centrifuge at a speed of 2000 rad / min for 20 minutes, and 8.3 g of polymer solid was obtained, corresponding to a polymer yield of 76%. The size of the polymer microspheres was 1200 nm. Among them, the concentration of the polymerization monomer was 6.3 wt% and the concentration of the initiator was 1.1 wt% based on the total weight of the homogeneous solution. The microspheres were named MW101.

[0181] The polymer microspheres MW101 were subjected to 1 H NMR determination showed that the molar content of structure unit A provided by maleic anhydride was 53% and the molar content of structure unit B provided by α-methylstyrene was 47% based on the total molar amount of each structure unit in the polymer.

[0182] Preparation Example A2

[0183] 4.9 g of maleic anhydride, 2 g of azobisisobutyronitrile, 6 g of α-methylstyrene, 10 ml of acetone and 90 ml of toluene were added into a 500 mL three-necked flask. After the mixture was uniformly mixed, a homogeneous solution was obtained, nitrogen was passed for 20 minutes, the three-necked flask was moved into a 70°C water bath, and the reaction was carried out for 5 h. After the reaction was completed, the obtained polymer emulsion suspension was separated by centrifuge at a speed of 2000 rad / min for 20 minutes, and 8 g of polymer solid was obtained, corresponding to a polymer yield of 73%. The size of the polymer microspheres was 1100 nm. Among them, the concentration of the polymerization monomer was 11.1 wt% and the concentration of the initiator was 3.1 wt% based on the total weight of the homogeneous solution. The microspheres were named MW102.

[0184] The polymer microspheres MW102 were subjected to 1H NMR measurement showed that the mole content of the structural unit A provided by maleic anhydride was 50% and the mole content of the structural unit B provided by α-methyl styrene was 50% based on the total mole amount of each structural unit in the polymer.

[0185] Preparation Example A3

[0186] 4.9 g of maleic anhydride, 0.9 g of azobisisobutyronitrile, 6 g of α-methyl styrene, 50 ml of acetone and 50 ml of toluene were added into a 500 mL three-necked flask, the material was uniformly mixed, and then nitrogen was passed for 20 minutes. The three-necked flask was moved into a 70°C water bath, and the reaction was carried out for 5 h. After the reaction was completed, the obtained polymer emulsion suspension was separated by centrifugation at a speed of 2000 rad / min for 20 minutes, and 7.5 g of polymer solid was obtained, corresponding to a polymer yield of 69%. The size of the polymer microspheres was 1000 nm. Among them, the concentration of the polymerized monomer was 11.5 wt% and the concentration of the initiator was 1 wt% based on the total weight of the homogeneous solution. The microspheres were named as MW103.

[0187] The polymer microspheres MW103 were subjected to 1 H NMR measurement showed that the mole content of the structural unit A provided by maleic anhydride was 51% and the mole content of the structural unit B provided by α-methyl styrene was 49% based on the total mole amount of each structural unit in the polymer.

[0188] Example 1

[0189] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0190] (1) Preparation of the polypropylene composition A:

[0191] Component a is a homopolymer polypropylene made by Beijing Research Institute of Chemical Industry, SINOPEC, with a melting point of 160°C, a melt flow rate (melt mass flow rate) of 3.2 g / 10 min and an isotacticity of 97%; component b is a polypropylene impact copolymer made by Beijing Research Institute of Chemical Industry, SINOPEC, with an ethylene content of 11 wt%, a melting point of 155°C, a cantilever beam impact strength of 23 KJ / m 2 (23°C) and a melt flow rate of 2.0 g / 10 min. The above prepared components were weighed and mixed according to the ratio, wherein 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.

[0192] The β crystal nucleating agent with the trade name of VP101B was added in an amount of 0.05 parts by weight. Then the mixture was added into a high-speed mixer for mixing, and then the mixed material was added into a feeder of a twin-screw extruder made by W&P Company, and the material was fed into the twin screw through the feeder, and the temperature of the screw was kept at 200-230°C during the processing, and the material was melt-mixed, extruded, pelletized and dried to obtain polypropylene composition pellets A, and the melting point of the polypropylene composition pellets A was detected to be 157°C.

[0193] (2) Preparation of polypropylene composition B i

[0194] Component x1 was a random copolymer polypropylene made by Beijing Research Institute of Chemical Industry, SINOPEC, which was an ethylene-propylene-butene terpolymer, and the molecular weight distribution Mw / Mn was 8.9, the melt flow rate was 8.1 g / 10 min, and the melting point was 130°C; component x2 was a random copolymer polypropylene made by Beijing Research Institute of Chemical Industry, SINOPEC, which was an ethylene-propylene-butene terpolymer, and the molecular weight distribution Mw / Mn was 7.6, the melt flow rate was 7.2 g / 10 min, and the melting point was 135°C; component x3 was a random copolymer polypropylene made by Beijing Research Institute of Chemical Industry, SINOPEC, which was an ethylene-propylene-butene terpolymer, and the molecular weight distribution Mw / Mn was 7.3, the melt flow rate was 6.6 g / 10 min, and the melting point was 140°C; component y was a polyolefin elastomer with the trade name of 6102, which was purchased from Exxon Company, and was an ethylene-propylene copolymer.

[0195] The components prepared above were weighed and mixed according to the ratio, wherein the mass fraction Wx of component x was 85 parts by weight, the mass fraction Wy of component y was 15 parts by weight, and the other steps were the same as step (1), and finally polypropylene composition B pellets (i.e. x+y=B, i=1, 2, 3) were obtained. i i i i i 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.

[0196] (3) Preparation of three-layer co-extruded polypropylene sheet

[0197] The polypropylene composition A and polypropylene composition B pellets prepared in step (1) and step (2) above were dried, and then the polypropylene composition A was added into a core layer extruder for multi-layer extrusion calendering, and the polypropylene composition B was added into a skin layer extruder for multi-layer extrusion calendering. i i ​​​​​​The upper and lower surface layer extruders of the multi-layer extrusion casting machine were added. After the pellets were co-extruded and compounded out of the extruder die, they were successively passed through calendering rollers, traction rollers, and then solid-phase stretching, edge cutting and winding, respectively, to produce sheets B1AB1, B2AB2 and B3AB3. The temperature of the extrusion casting was 230°C, and the temperature of the calendering rollers was 58°C. The temperature during the solid-phase stretching was 140°C, the stretching rate was 2 m / min, and the stretching ratio was 7 times.

[0198] The co-extruded film (polypropylene sheet) after stretching and winding was composed of an upper surface layer (outer film B i ), a core layer (film A) and a lower surface layer (outer film B i ). The thickness of the co-extruded film was 80 μm, and the thickness of the film layer A accounted for 80% of the total thickness of the sheet.

[0199] (4) Preparation of polypropylene fabric:

[0200] The three-layer co-extruded polypropylene sheet prepared in step (3) above was cut using a high-speed slitting machine with multiple blades to obtain oriented polypropylene ribbons with a width of 3 mm. The oriented ribbons were woven according to the designed fabric structure using a commercial weaving machine to produce plain polypropylene fabrics B1AB1, B2AB2 and B3AB3.

[0201] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0202] 50 g of POE-B, 50 g of EVA (6110), 4.2 g of 4,4'-oxobenzene sulfonyl hydrazide, 0.1 g of di-tert-butyl peroxide diisopropyl benzene, 0.1 g of stearic acid, 0.1 g of zinc stearate, 0.2 g of zinc oxide, 20 g of talc, and 1 g of MW101 were mixed in an internal mixer at a mixing temperature of 100°C for 10 min. The composition particles were prepared using a single-screw extruder with underwater pelletizing, and the composition was obtained by drying at 60°C.

[0203] (6) Preparation of polyolefin thermoplastic elastomer foamed sheet

[0204] The mold foaming machine was heated to 170°C and stabilized for 15 min. The composition pellets were added to the foaming machine. The foaming temperature was set to 175°C, the mold foaming time was 500 s, and the back pressure was 10 MPa. After 40 s of pressure holding, the pressure was released to jump out of the mold to obtain a polyolefin thermoplastic elastomer composition foamed material. The desired size of the foamed sheet was obtained by laser wire cutting. The density of the foamed sheet was 0.18 g / cm 3 , and the thickness after cutting was 5 mm.

[0205] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0206] The polypropylene fabrics prepared in step (4) above were stacked in turn, and the polypropylene fabrics prepared in step (4) above were stacked in turn, from bottom to top in the order of B3AB3, B2AB2, B1A1B1, B2AB2, B3AB3, and the total number of layers was 5. One piece of the polyolefin thermoplastic elastomer composition foamed sheet prepared in step (6) above was placed in the middle of the two sets of 5-layer fabrics (80 μm*5 (5 layers)*2 (2 sets) = 0.8 mm), i.e., the structure was that the upper and lower PP fabrics were stacked in the order of B3AB3, B2AB2, B1A1B1, B2AB2, B3AB3, and the total number of layers was 5, and the polyolefin thermoplastic elastomer composition foamed sheet was in the middle. The stacked polypropylene fabric and the polyolefin elastomer composition foamed sheet were simultaneously hot-pressed and fused, and then cooled and shaped to form a multilayer reinforced composite foamed sheet. The polypropylene fabric was placed in the warp direction at an angle of 90° between the warp and weft directions. The hot-pressing conditions used were: temperature 135°C, hot-pressing pressure 4 MPa, preheating time 160 s, and cooling time 520 s. The thickness of the multilayer reinforced composite foamed sheet prepared was 5.62 mm.

[0207] Example 2

[0208] This example is used to illustrate the preparation method of the multilayer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0209] (1) Preparation of polypropylene composition A:

[0210] Component a is a homopolymer polypropylene made by SINOPEC Beijing Research Institute of Chemical Engineering, with a melting point of 165°C, a melt flow rate of 8.1 g / 10 min, and an isotacticity of 97%; component b is a polypropylene impact copolymer made by SINOPEC Beijing Research Institute of Chemical Engineering, with an ethylene content of 8 wt%, a melting point of 155°C, a melt flow rate of 3.2 g / 10 min, and a cantilever beam impact strength of 25 KJ / m 2 (23°C). The components prepared above were weighed and mixed according to the proportions, wherein the mass fraction Wa of component a was 70 parts by weight, and the mass fraction Wb of component b was 30 parts by weight. 0.05 parts by weight of a β crystal nucleating agent with a trade name of VP101B was added. Then the mixture was added to a high-speed stirrer for mixing, and the mixed material was added to a feeder of a twin-screw extruder made by W&P Company, and the material entered the twin screw via the feeder. The temperature of the screw during the process was maintained at 200-230°C, and the material was melted, mixed, extruded, granulated, and dried to obtain polypropylene composition granules A. It was detected that the melting point of the polypropylene composition granules A was 161°C.

[0211] (2) Preparation of polypropylene composition B i

[0212] ​Component xi is a random copolymer polypropylene made by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene-butene terpolymer, with a molecular weight distribution Mw / Mn of 8.4, a melting point of 128℃, and a melt flow rate of 7.8 g / 10 min; component x2 is a random copolymer polypropylene made by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene-butene terpolymer, with a molecular weight distribution Mw / Mn of 7.6, a melting point of 134℃, and a melt flow rate of 6.9 g / 10 min; component x3 is a random copolymer polypropylene made by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene-butene terpolymer, with a molecular weight distribution Mw / Mn of 7.1, a melting point of 142℃, and a melt flow rate of 5.2 g / 10 min; component y is a polyolefin elastomer made by Sinopec Beijing Research Institute of Chemical Industry, which is an ethylene-propylene copolymer, with an ethylene content of 15% wt, a melting point of 105℃, and a melt flow rate of 9 g / 10 min under a load of 2.16 kg.

[0213] The above prepared components were weighed and mixed according to the ratio, wherein the mass fraction Wxi of component xi was 80 parts by weight, and the mass fraction Wy of component y was 20 parts by weight, and the other steps were the same as step (1), to finally obtain polypropylene composition B i The pellets (i.e. xi+y=B i , i = 1, 2, 3) were detected, and the melting point of B1 was 126℃, the melting point of B2 was 133℃, and the melting point of B3 was 140℃.

[0214] (3) Preparation of a three-layer co-extruded polypropylene sheet:

[0215] The preparation process was the same as step (3) of Example 1.

[0216] (4) Preparation of a polypropylene fabric:

[0217] The preparation process was the same as step (4) of Example 1.

[0218] (5) Preparation of a polyolefin thermoplastic elastomer composition for a foamed sheet:

[0219] 50 g of POE-H, 50 g of EVA (2806), 5.3 g of 2,4-toluene disulfonyl hydrazide, 0.15 g of di-tert-butyl peroxide diisopropyl benzene, 0.11 g of stearic acid, 0.12 g of zinc stearate, 0.21 g of zinc oxide, 25 g of silicon dioxide, and 0.5 g of MW102 were mixed by internal mixing, the internal mixing and kneading temperature was 105℃, the mixing time was 9.5 min, and then the composition particles were prepared by using a single screw extruder with air cooling and pelletizing, without drying.

[0220] (6) Preparation of a polyolefin thermoplastic elastomer composition foamed sheet

[0221] The molding foaming machine was heated to 175℃ and stabilized for 16 minutes; the granulated composition was added into the foaming machine; the foaming temperature was set to 180℃, the molding foaming time was 510s, the back pressure was 12MPa; after 50s of pressure maintaining, the pressure was released to get the polyolefin thermoplastic elastomer composition foaming material, and the foaming sheet with desired size was obtained by laser wire cutting. The density of the foaming sheet was 0.15g / cm 3 , and the thickness after cutting was 5mm.

[0222] (7) Preparation of the multi-layer reinforced composite foaming sheet:

[0223] The preparation process was the same as step (7) of Example 1. The thickness of the prepared multi-layer reinforced composite foaming sheet was 5.57mm.

[0224] Example 3

[0225] This example is used to illustrate the preparation method of the multi-layer reinforced composite foaming sheet provided by the present application, which comprises the following steps:

[0226] (1) Preparation of polypropylene composition A:

[0227] The same as Example 1, wherein the mass fraction Wa of component a is 90 parts by weight, and the mass fraction Wb of component b is 10 parts by weight. 0.05 parts by weight of β crystal nucleating agent with the trade name of VP101B was added. Polypropylene composition A granules were obtained, and it was detected that the melting point of the polypropylene composition granules A was 158℃.

[0228] (2) Preparation of polypropylene composition B: i

[0229] The same as Example 1, wherein the mass fraction Wx i of corresponding component x i is 90 parts by weight, and the mass fraction Wy of component y is 10 parts by weight, and finally polypropylene composition B i granules were obtained (i.e. x i +y=B i , i=1, 2, 3), and it was detected that the melting point of B1 was 128℃, the melting point of B2 was 134℃, and the melting point of B3 was 139℃.

[0230] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0231] The preparation process was the same as step (3) of Example 1.

[0232] (4) Preparation of polypropylene fabric:

[0233] The preparation process was the same as step (4) of Example 1.

[0234] ​(5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0235] 40 g of POE-O, 60 g of EVA (5110) and 4.6 g of triphosphine triazine, 0.15 g of di-tert-butyl peroxide diisopropyl benzene, 0.13 g of stearic acid, 0.15 g of zinc stearate, 0.23 g of zinc oxide, 32 g of kaolin and 1 g of MW103 were mixed by internal mixing, the internal mixing and kneading temperature was 105℃, the mixing time was 9.5 min, and then the composition particles were prepared by using a single screw extruder with air cooling and pelletizing, without drying.

[0236] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0237] The mold foaming machine was heated to 168℃ and stabilized for 20 min; the composition pellet particles were added to the foaming machine; the foaming temperature was set to 173℃, the mold foaming time was 580 s, the back pressure was 9 MPa; after the pressure maintaining time of 70 s, the pressure was released and the mold was jumped to obtain the polyolefin thermoplastic elastomer composition foamed material, and the foamed sheet with the required size was obtained by laser wire cutting. The density of the foamed sheet was 0.21 g / cm 3 , and the thickness after cutting was 5 mm.

[0238] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0239] The preparation process was the same as step (7) of Example 1. That is, the structure of the multi-layer reinforced composite foamed sheet was 5 (5 layers of fabric) + 1 (foamed sheet) + 5 (5 layers of fabric); the thickness of the prepared multi-layer reinforced composite foamed sheet was 5.65 mm.

[0240] Example 4

[0241] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0242] (1) Preparation of polypropylene composition A:

[0243] The preparation process was the same as step (1) of Example 1.

[0244] (2) Preparation of polypropylene composition B i :

[0245] The preparation process was the same as step (2) of Example 1.

[0246] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0247] The main steps were the same as Example 1. The thickness of the polypropylene sheet was 80 μm, and the thickness ratio of the film layer A to the total thickness of the sheet was 90%.

[0248] (4) Preparation of polypropylene fabric:

[0249] The preparation process is the same as step (4) of Example 1.

[0250] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0251] 40 g of POE-O, 60 g of EVA (5110), 4.6 g of triphosphine triazine, 0.15 g of di-tert-butyl peroxide diisopropylbenzene, 0.13 g of stearic acid, 0.15 g of zinc stearate, 0.23 g of zinc oxide, 32 g of kaolin and 1 g of MW103 were mixed by internal mixing, the internal mixing and kneading temperature was 105℃, the mixing time was 9.5 min, and then the composition particles were prepared by using a single screw extruder with air cooling and pelletizing, without drying.

[0252] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0253] The mold foaming machine was heated to 168℃ and stabilized for 20 min; the composition pellet particles were added to the foaming machine; the foaming temperature was set to 173℃, the mold foaming time was 580 s, and the back pressure was 9 MPa; after 70 s of pressure maintaining time, the pressure was released and the mold was jumped to obtain the polyolefin thermoplastic elastomer composition foamed material, and the foamed sheet with the required size was obtained by laser wire cutting. The density of the foamed sheet was 0.21 g / cm 3 , and the thickness after cutting was 5 mm.

[0254] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0255] The preparation process is the same as step (7) of Example 1. The thickness of the prepared multi-layer reinforced composite foamed sheet polypropylene composite material is 5.65 mm.

[0256] Example 5

[0257] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0258] (1) Preparation of polypropylene composition A:

[0259] The preparation process is the same as step (1) of Example 1.

[0260] (2) Preparation of polypropylene composition B i :

[0261] The preparation process is the same as step (2) of Example 1.

[0262] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0263] The main preparation process is the same as step (3) of Example 1. The sheet stretching ratio is 10 times.

[0264] (4) Preparation of polypropylene fabric:

[0265] The preparation process is the same as step (4) of Example 1.

[0266] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0267] 20 g of POE-B, 20 g of POE-O, 60 g of EVA (5110), 5.7 g of dinitrosopentamethylene tetramine, 0.15 g of 1-dimethyl-3-hydroxybutyl, 0.10 g of stearic acid, 0.12 g of zinc stearate, 0.21 g of zinc oxide, 27 g of zinc borate, and 1.5 g of MW101 are mixed by internal mixing, the internal mixing and kneading temperature is 95°C, the mixing time is 11.5 min, and then the composition particles are prepared by using a single screw extruder in combination with air cooling and pelletizing, without drying.

[0268] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0269] The mold foaming machine is heated to 173°C and stabilized for 30 min; the composition pellet particles are added to the foaming machine; the foaming temperature is set to 178°C, the mold foaming time is 600 s, the back pressure is 7 MPa; after the pressure maintaining time of 40 s, the pressure is released and the mold is jumped to obtain the polyolefin thermoplastic elastomer composition foamed material, and the foamed sheet with the required size is obtained by laser wire cutting. The density of the foamed sheet is 0.25 g / cm 3 , and the thickness after cutting is 5 mm.

[0270] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0271] The preparation method is the same as step (7) of Example 1, and the thickness of the prepared multi-layer reinforced composite foamed sheet is 5.70 mm.

[0272] Example 6

[0273] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0274] (1) Preparation of polypropylene composition A:

[0275] The preparation process is the same as step (1) of Example 1.

[0276] (2) Preparation of polypropylene composition B i :

[0277] The preparation process is the same as step (2) of Example 1.

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

[0279] The preparation procedure was the same as step (3) of Example 1.

[0280] (4) Preparation of a polypropylene fabric:

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

[0282] (5) Preparation of a polyolefin thermoplastic elastomer composition for a foamed sheet:

[0283] The preparation procedure was the same as step (5) of Example 2.

[0284] (6) Preparation of a foamed sheet of a polyolefin thermoplastic elastomer composition:

[0285] The preparation procedure was the same as step (6) of Example 2.

[0286] (7) Preparation of a multi-layer reinforced composite foamed sheet:

[0287] The preparation procedure was the same as step (7) of Example 1. The polypropylene fabric was placed at an angle of 45° between the warp and the weft directions. The thickness of the prepared multi-layer reinforced composite foamed sheet was 5.62 mm.

[0288] Example 7

[0289] This example is used to illustrate a method for preparing a multi-layer reinforced composite foamed sheet according to the present application, which comprises the following steps:

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

[0291] The preparation procedure was the same as step (1) of Example 1.

[0292] (2) Preparation of a polypropylene composition B i

[0293] The preparation procedure was the same as step (2) of Example 1.

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

[0295] The preparation procedure was the same as step (3) of Example 1.

[0296] (4) Preparation of a polypropylene fabric:

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

[0298] (5) Preparation of a polyolefin thermoplastic elastomer composition for a foamed sheet:

[0299] The preparation procedure was the same as step (5) of Example 1. ​

[0300] (6) Preparation of polyolefin thermoplastic elastomer foamed sheet

[0301] The preparation process is the same as step (6) of Example 1.

[0302] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0303] The preparation process is the same as step (7) of Example 1. Instead of preparing the polypropylene fabric, the five-layer co-extruded polypropylene sheet prepared in step (3) is used to replace the polypropylene fabric obtained in step (4) of Example 1, i.e. the sheet is B3AB3, B2AB2, B1AB1, B2AB2, B3AB3 from bottom to top, and the total number of layers is 5, and the step (5) of Example 1 is followed to perform the sequential lamination and hot pressing. The polyolefin composition foamed sheet is in the middle of the two groups of 5-layer sheets, and the thickness of the prepared multi-layer reinforced composite foamed sheet is 5.23 mm.

[0304] Example 8

[0305] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the present application, which comprises the following steps:

[0306] (1) Preparation of polypropylene composition A:

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

[0308] (2) Preparation of polypropylene composition B i :

[0309] The preparation process is the same as step (2) of Example 1.

[0310] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0311] The preparation process is the same as step (3) of Example 1.

[0312] (4) Preparation of polypropylene fabric:

[0313] The preparation process is the same as step (4) of Example 1.

[0314] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0315] The preparation process is the same as step (5) of Example 1.

[0316] (6) Preparation of polyolefin thermoplastic elastomer foamed sheet:

[0317] The preparation process is the same as step (6) of Example 1. But the thickness after cutting is 10 mm.

[0318] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0319] The preparation process is the same as step (7) of Example 1. The difference is that one piece of the foamed sheet prepared in step (6) is placed in the middle of the two sets of 5-layer polypropylene fabric (B3AB3, B2AB2, B1AB1, B2AB2, B3AB3 from bottom to top, the total number of layers is 5). The thickness of the prepared multi-layer reinforced composite foamed sheet is 10.45 mm.

[0320] Example 9

[0321] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:

[0322] (1) Preparation of polypropylene composition A:

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

[0324] (2) Preparation of polypropylene composition B i

[0325] The preparation process is the same as step (2) of Example 1.

[0326] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0327] The preparation process is the same as step (3) of Example 1.

[0328] (4) Preparation of polypropylene fabric:

[0329] The preparation process is the same as step (4) of Example 1.

[0330] (5) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0331] The preparation process is the same as step (5) of Example 1.

[0332] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet

[0333] The preparation process is the same as step (6) of Example 1. But the thickness after cutting is 20 mm.

[0334] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0335] The preparation process is the same as step (7) of Example 1. The difference is that one piece of the foamed sheet prepared in step (6) is placed in the middle of the two sets of 5-layer polypropylene fabric (B3AB3, B2AB2, B1AB1, B2AB2, B3AB3 from bottom to top, the total number of layers is 5). The thickness of the prepared multi-layer reinforced composite foamed sheet is 10.45 mm.

[0336] Example 10

[0337] This example is used to illustrate the preparation method of the multi-layer reinforced composite foamed sheet provided by the application, which comprises the following steps:​

[0338] (1) Preparation of polypropylene composition A:

[0339] The preparation process is the same as step (1) of Example 1.

[0340] (2) Preparation of polypropylene composition B: i

[0341] The preparation process is the same as step (2) of Example 1.

[0342] (3) Preparation of three-layer co-extruded polypropylene sheet:

[0343] The preparation process is the same as step (3) of Example 1.

[0344] (4) Preparation of polypropylene fabric and reinforced composite sheet:

[0345] The preparation process is the same as step (4) of Example 1, respectively obtaining polypropylene fabrics B1AB1, B2AB2, B3AB3. The prepared polypropylene fabrics are stacked in order from bottom to top as B3A3B3, B2A2B2, B1A1B1, B2A2B2, B3A3B3, and the total number of layers is 5. The stacked polypropylene fabric is hot-pressed and fused, and then cooled and shaped to obtain a reinforced composite sheet. The polypropylene fabric is placed in the warp direction at an angle of 90° with the warp direction. The hot-pressing conditions used are: temperature 145°C, hot-pressing pressure 5MPa, preheating time 90s, hot-pressing time 90s, and cooling time 300s.

[0346] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet:

[0347] The preparation process is the same as step (5) of Example 1.

[0348] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0349] The preparation process is the same as step (6) of Example 1. The cutting thickness is still 5mm.

[0350] (7) Preparation of multi-layer reinforced composite foamed sheet:

[0351] ​The main steps are the same as step (7) of Example 1. The difference is that the reinforcing composite sheet is prepared by including 3 groups of 5-layer polypropylene fabric in the stacked polypropylene sheet, and 2-layer polyolefin elastomer composition foamed sheet. The hot pressing equipment is also different. The reinforcing composite sheet and the polyolefin elastomer composition foamed sheet are placed in an oven with a pressure plate on the topmost reinforcing composite sheet. The hot pressing temperature is close to the surface softening temperature of the polyolefin thermoplastic elastomer, which is 70°C. The stacked polypropylene sheet and the polyolefin elastomer composition reach 70°C and are kept at this temperature for 5 minutes. Hot pressing is completed in 30 seconds, with a hot pressing pressure of 3.5 MPa. The thickness of the prepared multilayer reinforced composite foamed sheet is 10.77 mm.

[0352] The structure is shown as follows:

[0353]

[0354] Example 11

[0355] This example is used to illustrate the preparation method of the multilayer reinforced composite foamed sheet provided by the application, which comprises the following steps:

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

[0357] The preparation process is the same as step (1) of Example 1.

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

[0359] The preparation process is the same as step (2) of Example 1.

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

[0361] The preparation process is the same as step (3) of Example 1.

[0362] (4) Preparation of polypropylene fabric:

[0363] The preparation process is the same as step (4) of Example 1.

[0364] (5) Polyolefin thermoplastic elastomer composition foamed sheet:

[0365] The preparation process is the same as step (5) of Example 1.

[0366] (6) Preparation of polyolefin thermoplastic elastomer composition foamed sheet:

[0367] The preparation process is the same as step (6) of Example 1. But the thickness after cutting is 60 mm.

[0368] (7) Preparation of multilayer reinforced composite foamed sheet:

[0369] The preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (5) of Example 1, the preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (6) of Example 1, the preparation procedure of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1, and a multi-layer reinforced composite foamed sheet is obtained, which has a thickness close to that of Example 1, i.e. 5.61 mm.

[0370] Comparative Example 1

[0371] A three-layer co-extruded polypropylene sheet was prepared according to the method of Example 1. Only polypropylene composition A was used to be extruded into a single-layer film with a thickness of 80 μm. The polypropylene fabric was prepared according to the method of Example 1.

[0372] The preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (5) of Example 1, the preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (6) of Example 1, the preparation procedure of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1, and a multi-layer reinforced composite foamed sheet is obtained, which has a thickness close to that of Example 1, i.e. 5.61 mm.

[0373] Comparative Example 2

[0374] A three-layer co-extruded polypropylene sheet was prepared according to the method of Example 1. Only polypropylene composition B i was used to be extruded into a single-layer film with a thickness of 80 μm. The polypropylene fabric was prepared according to the method of Example 1.

[0375] The preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (5) of Example 1, the preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (6) of Example 1, the preparation procedure of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1, and a multi-layer reinforced composite foamed sheet is obtained, which has a thickness close to that of Example 1, i.e. 5.63 mm.

[0376] Comparative Example 3

[0377] A three-layer co-extruded polypropylene sheet was prepared according to the method of Example 1. Only component b was contained in polypropylene composition A. The polypropylene fabric was prepared according to the method of Example 1.

[0378] The preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (5) of Example 1, the preparation procedure of the foamed sheet with polyolefin thermoplastic elastomer composition is the same as step (6) of Example 1, the preparation procedure of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1, and a multi-layer reinforced composite foamed sheet is obtained, which has a thickness close to that of Example 1, i.e. 5.62 mm.

[0379] Comparative Example 4

[0380] A three-layer co-extruded polypropylene sheet was prepared according to the method of Example 1. Only polypropylene composition B iThe polypropylene fabric was prepared according to the method of Example 1.

[0381] The polyolefin thermoplastic elastomer composition for foamed sheet was prepared according to the procedure of step (5) of Example 1, the polyolefin thermoplastic elastomer composition foamed sheet was prepared according to the procedure of step (6) of Example 1, and the multilayer reinforced composite foamed sheet was prepared according to the procedure of step (7) of Example 1, to obtain a multilayer reinforced composite foamed sheet with a thickness close to that of Example 1, i.e. 5.63 mm.

[0382] Comparative Example 5

[0383] The co-extruded polypropylene sheet was prepared according to the method of Example 6, except that component B i The components were selected in the following manner: component xl was a random copolymer polypropylene made by SINOPEC Beijing Research Institute of Chemical Industry, which was an ethylene-propylene-butene terpolymer with a melting point of 140°C; component x2 was a random copolymer polypropylene made by SINOPEC Beijing Research Institute of Chemical Industry, which was an ethylene-propylene-butene terpolymer with a melting point of 135°C; component x3 was a random copolymer polypropylene made by SINOPEC Beijing Research Institute of Chemical Industry, which was an ethylene-propylene-butene terpolymer with a melting point of 130°C; the melt flow rates of components xl-x3 were all in the range of 2-10 g / 10 min.

[0384] The polypropylene composition B was finally obtained i The pellets (i.e. xl-x3 i +y = B i , i = 1, 2, 3) were detected to have a melting point of 138°C for Bl, a melting point of 132°C for B2, and a melting point of 127°C for B3. The polypropylene fabric was prepared according to the method of Example 1.

[0385] The polyolefin thermoplastic elastomer composition for foamed sheet was prepared according to the procedure of step (5) of Example 1, the polyolefin thermoplastic elastomer composition foamed sheet was prepared according to the procedure of step (6) of Example 1, and the multilayer reinforced composite foamed sheet was prepared according to the procedure of step (7) of Example 1, to obtain a multilayer reinforced composite foamed sheet with a thickness close to that of Example 1, i.e. 5.63 mm.

[0386] Comparative Example 6

[0387] The preparation process of the polyolefin thermoplastic elastomer composition for foamed sheet is the same as step (5) of Example 1, the preparation process of the polyolefin thermoplastic elastomer composition foamed sheet is the same as step (6) of Example 1, and the preparation process of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1. The difference is that two pieces of square glass fiber / nylon composite sheet with a thickness of 1.7 mm are combined above and below the two pieces of polyolefin thermoplastic elastomer composition foamed sheet prepared in step (6), i.e., the square glass fiber / nylon composite sheet is used instead of the five-layer fabric in Example 1, to obtain a multi-layer reinforced composite foamed sheet with a thickness of 8.24 mm.

[0388] Comparative Example 7

[0389] The three-layer co-extruded polypropylene sheet and the polypropylene fabric were prepared according to the method of Example 1.

[0390] The preparation process of the polyolefin thermoplastic elastomer composition for foamed sheet is the same as step (5) of Example 1, the preparation process of the polyolefin thermoplastic elastomer composition foamed sheet is the same as step (6) of Example 1, and the preparation process of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1. The difference is that two pieces of square glass fiber / nylon composite sheet with a thickness of 1.7 mm are combined above and below the two pieces of polyolefin thermoplastic elastomer composition foamed sheet prepared in step (6), i.e., the square glass fiber / nylon composite sheet is used instead of the five-layer fabric in Example 1, to obtain a multi-layer reinforced composite foamed sheet with a thickness of 8.24 mm.

[0391] Comparative Example 8

[0392] The three-layer co-extruded polypropylene sheet and the polypropylene fabric were prepared according to the method of Example 1.

[0393] The preparation process of the polyolefin thermoplastic elastomer composition for foamed sheet is the same as step (5) of Example 1, the preparation process of the polyolefin thermoplastic elastomer composition foamed sheet is the same as step (6) of Example 1, and the preparation process of the multi-layer reinforced composite foamed sheet is the same as step (7) of Example 1. The difference is that two pieces of square glass fiber / nylon composite sheet with a thickness of 1.7 mm are combined above and below the two pieces of polyolefin thermoplastic elastomer composition foamed sheet prepared in step (6), i.e., the square glass fiber / nylon composite sheet is used instead of the five-layer fabric in Example 1, to obtain a multi-layer reinforced composite foamed sheet with a thickness of 8.24 mm.

[0394] Comparative Example 9

[0395] The preparation method of the multi-layer reinforced composite foamed sheet comprises the following steps:

[0396] (1) Preparation of polypropylene composition A:

[0397] The preparation process is the same as step (1) of Example 1.

[0398] (2) Preparation of polypropylene composition B i

[0399] The preparation procedure was the same as step (2) of Example 1.

[0400] (3) Preparation of three-layer co-extruded polypropylene sheet

[0401] The preparation procedure was the same as step (3) of Example 1.

[0402] (4) Preparation of polypropylene fabric

[0403] The preparation procedure was the same as step (4) of Example 1.

[0404] (5) Preparation of polyolefin thermoplastic elastomer composition for foamed sheet

[0405] The preparation procedure was the same as step (5) of Example 1.

[0406] (6) Preparation of polyolefin thermoplastic elastomer composition

[0407] The preparation procedure was the same as step (6) of Example 1.

[0408] (7) Preparation of multi-layer reinforced composite foamed sheet

[0409] The main procedure was the same as step (7) of Example 1. The difference was that 10 layers of polypropylene fabric were included in the stacked polypropylene sheet on one side of the foamed sheet prepared in step (6), and the thickness of the obtained multi-layer reinforced composite foamed sheet was 5.65 mm.

[0410] Comparative Example 10

[0411] The preparation procedure of the multi-layer reinforced composite sheet was the same as Example 1, but without step (6), i.e., without the polyolefin thermoplastic elastomer composition foamed sheet, and the upper and lower groups of polypropylene fabric in Example 1 were hot-pressed, and the thickness of the obtained composite sheet was 0.8 mm.

[0412] Comparative Example 11

[0413] The procedure was the same as step (5) + step (6) of Example 1, without the reinforcing sheet and without the hot-pressing process, and the thickness of the obtained polyolefin thermoplastic elastomer foamed sheet was 5 mm.

[0414] Comparative Example 12

[0415] The procedure was the same as Example 11, but the polyolefin elastomer composition foamed sheet did not contain maleic anhydride microspheres, and a multi-layer reinforced composite foamed sheet was obtained, with a thickness of 58.15 mm.

[0416] Experimental Example

[0417] ​The polypropylene composite foamed sheet obtained in the above examples and comparative examples was tested according to the following method, and the test results are shown in Table 1.

[0418] (1) Tensile strength: sample preparation and determination were carried out according to the method specified in GB / T1040.1-2018; the tensile strength in the table is the tensile strength of the foamed composite formed body, and the cross-sectional area needs to be divided when testing the tensile strength, and the foamed sheet part contributes to the thickness and low strength.

[0419] (2) Interlayer peeling strength: sample preparation and determination were carried out according to the method specified in GB / T 3903.39-2019.

[0420] (3) Falling weight impact strength: determination was carried out according to the method specified in GB / T14153-1993.

[0421] (4) The apparent density of the composite foamed sheet was prepared and determined according to the method specified in GB / T6343.

[0422] (5) The thermal conductivity coefficient of the composite foamed sheet was prepared and determined according to the method specified in GB / T 10294.

[0423] Table 1

[0424]

[0425]

[0426] As can be seen from the results of Table 1, compared with the ordinary foamed sheet without composite reinforcement of Comparative Example 11, the polyolefin thermoplastic elastomer composite foamed sheet prepared according to the present application has good tensile properties and impact resistance, and has good interlayer peeling strength at a lower hot pressing temperature. And it does not significantly increase the thermal conductivity coefficient, reduces the heat insulation capacity.

[0427] As can be seen from Comparative Examples 1-5, using only a single-layer sheet structure, a single polymer component, or using a layer ratio outside the scope of the examples will result in a decrease in the performance of the stacked polypropylene sheet or fabric, thereby resulting in a decrease in the performance of the final composite foamed sheet.

[0428] As can be seen from Example 11 and Comparative Example 8, increasing the thickness ratio of the polyolefin elastomer composition foamed sheet is beneficial to reduce the thermal conductivity of the composite foamed material. Excessive hot pressing forming pressure causes the microcellular structure of the polyolefin elastomer composition foamed sheet in Comparative Example 8 to be broken, thereby significantly reducing the falling weight impact and lightweight performance.

[0429] From Examples 9, 12, it can be seen that the number of polypropylene fabric and the number of foamed sheet have a significant effect on the final product, and with the increase of the number of fabric layers and the thickness of foamed sheet, the physical properties (drop hammer performance) are improved.

[0430] From Example 11 and Comparative Example 12, it can be seen that when the thickness of the foamed sheet is large (60 mm), the polyolefin thermoplastic elastomer composite foamed sheet can be hot-pressed with the polypropylene laminated material in multiple layers, thanks to the good interface bonding ability of the maleic anhydride microspheres, and the multi-layer polyolefin elastomer composition foamed sheet without maleic anhydride microspheres is difficult to be hot-pressed with the polypropylene fabric to obtain a foamed product with sufficient peel strength. That is, from the comparative example 12, it can be seen that the multi-layer reinforced composite foamed sheet can be hot-pressed without maleic anhydride microspheres in the polyolefin elastomer composition foamed sheet, but the interlayer tear strength is reduced to 70% of the original Example 11.

[0431] From Comparative Example 7, it can be seen that although the use of glass fiber / nylon composite sheet, which is commonly used in the industry, can also improve the physical properties of the composite foamed sheet to approach the level of the examples, due to the poor compatibility of the glass fiber / nylon composite sheet with the polyolefin thermoplastic elastomer composition foamed sheet, and at the same time, the thermal conductivity of the glass fiber reinforced nylon (i.e. glass fiber / nylon composite sheet) is high, so the peel strength and thermal insulation performance of the composite foamed sheet are also greatly reduced, and in addition, the high density of the glass fiber / nylon composite sheet also significantly increases the apparent density of the composite foamed sheet.

[0432] From Example 5, it can be seen that the lower the foaming ratio of the polyolefin elastomer composition foamed material, the higher the density, and the smaller the deformation during hot pressing, and the greater the thickness.

[0433] From Example 7, it can be seen that when polypropylene sheet is directly used without using woven polypropylene fabric, the thermoplastic elastomer composition foamed material is compressed more obviously during hot pressing, and the result is that the density of the multi-layer reinforced composite foamed sheet is large and the thermal conductivity is low. It is preferred to use polypropylene fabric.

[0434] From Comparative Example 9, it can be seen that only when the outer layer of the multi-layer reinforced composite foamed sheet is the reinforced composite sheet, i.e. the structure is a sandwich structure, can the present application be realized.

[0435] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0436] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as exactly that endpoint point. The endpoints of the ranges and any values are understood to be approximate values. For ranges having an upper and lower limit, the range can be understood to include each integer within the defined range. The upper and lower limits of the range can independently be included in the range, or independently excluded from the range. The range can also be understood to include single values within the range, which can be the upper or lower limit of the range. For ranges having an upper and lower limit, the range can be understood to include each integer within the defined range. The upper and lower limits of the range can independently be included in the range, or independently excluded from the range. The range can also be understood to include single values within the range, which can be the upper or lower limit of the range.

Claims

1. A multi-layer reinforced composite foam sheet having a laminated structure, comprising at least two layers of reinforced composite sheets and at least one layer of a thermoplastic elastomer composition foam sheet, wherein the outer layers of the multi-layer reinforced composite foam sheet are all reinforced composite sheets; The reinforced composite sheet comprises at least one layer of polypropylene sheet and / or at least one layer of polypropylene fabric woven from polypropylene sheets; wherein, The polypropylene sheet comprises a layer A and layers B and B' located on both sides of the layer A, with a structure of BAB'; wherein layer A contains a polypropylene composition A, layer B and layer B' are the same as or different from each other, and each layer contains a polypropylene composition B and a polypropylene composition B', and the melting point of the polypropylene composition A is greater than the melting point of the polypropylene composition B and the polypropylene composition B'; wherein the polypropylene composition A comprises homopolymer polypropylene a and impact copolymer polypropylene b; the polypropylene composition B and the polypropylene composition B' each comprise random copolymer polypropylene x and thermal bonding enhancer y; The thermoplastic elastomer composition foamed sheet and the reinforced composite sheet are bonded by hot pressing fusion.

2. The multi-layer reinforced composite foam 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% of homopolypropylene a and 1-50 wt% of impact copolymer polypropylene b; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', the polypropylene composition B and the polypropylene composition B' each comprise 70-99 wt% of random copolymerized polypropylene x and 1-30 wt% of thermal adhesion enhancer y.

3. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: Based on the total weight of the polypropylene composition A, the polypropylene composition A comprises 70-90 wt% of homopolypropylene a and 10-30 wt% of impact copolymer polypropylene b; and / or, Based on the total weight of the polypropylene composition B and the polypropylene composition B', the polypropylene composition B and the polypropylene composition B' each comprise 80-90 wt% of random copolymerized polypropylene x and 10-20 wt% of thermal adhesion enhancer y.

4. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: Based on the total thickness of the polypropylene sheet, the thickness of the layer A accounts for 51%-89% of the total thickness.

5. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: Based on the total thickness of the polypropylene sheet, the thickness of the layer A accounts for 71%-89% of the total thickness.

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

7. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The homopolymer polypropylene a has: A melting point of 150-170°C; and / or The melt flow rate at 230°C and 2.16 kg load is 0.5-50 g / 10 min; and / or The isotacticity is not less than 96%.

8. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The homopolymer polypropylene a has: A melting point of 160-170°C; and / or The melt flow rate at 230°C and a load of 2.16 kg is 1-20 g / 10 min.

9. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The homopolymer polypropylene a has: The melt flow rate at 230°C and 2.16 kg load is 2.5-18 g / 10 min.

10. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The melting point of the impact-resistant copolymer polypropylene b is 150-170° C.: and / or, The monomer of the impact-resistant copolymer polypropylene b copolymerized with propylene is ethylene or butene; and / or, The impact 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 20KJ / m 2 .

11. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The monomer of the impact-resistant copolymer polypropylene b copolymerized with propylene is butene; and / or, The impact copolymer polypropylene b has a melt flow rate of 1-20 g / 10 min at 230° C. and a load of 2.16 kg.

12. The multi-layer reinforced composite foam sheet according to claim 1, 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 a load of 2.16 kg.

13. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The random copolymer polypropylene x has: A melting point of 110-150°C; and / or The melt flow rate at 230°C and 2.16 kg load is 0.5-50 g / 10 min; and / or a molecular weight distribution Mw / Mn of 5-12; and / or, The random copolymer polypropylene x is a copolymer of propylene and ethylene and / or butene.

14. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The random copolymer polypropylene x has: A melting point of 120-140°C; and / or A melt flow rate of 1-20 g / 10 min at 230° C. and 2.16 kg load; and / or a molecular weight distribution Mw / Mn of 7-10; and / or, The random copolymer polypropylene x is an ethylene-propylene-butene terpolymer and / or a propylene-ethylene binary copolymer.

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

16. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The thermal adhesion enhancer y has: The melting point or viscosity flow temperature is 50-110°C; and / or, The melt flow rate at 190°C and a load of 2.16 kg is 0.5-50 g / 10 min.

17. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The thermal adhesion enhancer y has: The melt flow rate at 190°C and a load of 2.16 kg is 1-20 g / 10 min.

18. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The thermal adhesion enhancer y has: The melt flow rate at 190°C and a load of 2.16 kg is 1-18 g / 10 min.

19. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The thermal adhesion enhancer y is selected from one or more of polyolefin elastomer, EPDM rubber, SEBS, SBS, EVA, and petroleum resin.

20. The multi-layer reinforced composite foam sheet according to claim 19, characterized in that: The thermal adhesion enhancer y is a polyolefin elastomer and / or a petroleum resin.

21. The multi-layer reinforced composite foam sheet according to claim 19, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene, propylene and / or α-olefin; and / or, The petroleum resin is a C5 and / or C9 hydrogenated petroleum resin with a softening point of 100-150°C.

22. The multi-layer reinforced composite foam sheet according to claim 19, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene, propylene and / or α-olefin, and the α-olefin is a C4-C12 α-olefin; and / or, The petroleum resin is a cyclopentadiene type resin.

23. The multi-layer reinforced composite foam sheet according to claim 19, characterized in that: The polyolefin elastomer is a copolymer elastomer of ethylene, propylene and / or α-olefin, and the α-olefin is 1-butene and / or 1-octene.

24. The multi-layer reinforced composite foam sheet according to claim 1, characterized in that: The layer A also contains a β-crystal nucleating agent.

25. The multi-layer reinforced composite foam sheet according to claim 24, characterized in that: The β-crystal nucleating agent is at least one selected from the group consisting of condensed ring aromatic hydrocarbons, Group IIA two-component complexes, aromatic diamides, rare earth compounds, and cyclic dicarboxylates; and / or, Relative to 100 parts by weight of the polypropylene composition A, the content of the β-crystal nucleating agent in layer A is 0.01-0.5 parts by weight.

26. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The melting point of the homopolymer polypropylene a in the polypropylene composition A is greater than the melting point of the random copolymer polypropylene x in the polypropylene compositions B and B'; and / or, The BAB' layer structure of the polypropylene sheet is obtained by co-extruding components including the polypropylene composition A and the polypropylene compositions B and B'.

27. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The melting point of the homopolymer polypropylene a in the polypropylene composition A is greater than the melting point of the random copolymer polypropylene x in the polypropylene compositions B and B', and the temperature difference between the corresponding melting points is greater than or equal to 10 degrees.

28. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: Each layer of the reinforced composite sheet comprises a plurality of polypropylene sheet unit groups stacked in sequence; each polypropylene sheet unit group comprises at least one identical or different polypropylene sheet unit, each polypropylene sheet unit comprises a core layer A i and located in the core layer A i Outer layer B on both sides i , B' i , structure B i A i B' i The structure of the reinforced composite sheet is from bottom to top as follows: nth group... ith group... 2nd group, 1st group, 2nd group... ith group... nth group, and the total number of stacked 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 Containing polypropylene composition A i , outer layer B i With outer layer B' i The same or different, each corresponding 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 average melting point of all outer layers in the i-th group is greater than or equal to the average melting point of all outer layers in the i-1-th group.

29. The multi-layer reinforced composite foam sheet according to claim 28, characterized in that: Polypropylene composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in melting points of each of the following 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 is 1-40° C.; and / or, 2≤n≤100; and / or, Each polypropylene sheet unit group independently comprises 1 to 10 identical or different polypropylene sheet units.

30. The multi-layer reinforced composite foam sheet according to claim 28, characterized in that: Polypropylene composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in melting points of each of the following 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, and is 1-10° C.; and / or 2≤n≤50; and / or, Each polypropylene sheet unit group independently comprises 1 to 5 identical or different polypropylene sheet units.

31. The multi-layer reinforced composite foam sheet according to claim 28, characterized in that: Polypropylene composition A i The melting point of polypropylene composition B i The difference in melting points, polypropylene composition A i The melting point of polypropylene composition B' i The difference in melting points of each of the following is greater than or equal to 20°C; and / or, The difference between the average value of the melting points of all outer layers in the i-th group and the average value of the melting points of all outer layers in the i-1-th group, which are the same or different, is 1-5°C.

32. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The multi-layer reinforced composite foam sheet has a multi-layer sandwich structure; and / or, Based on the total thickness of the multi-layer reinforced composite foam sheet, the total thickness of the reinforced composite sheet accounts for 1.3%-15.5% of the total thickness of the multi-layer reinforced composite foam sheet; and / or, the number of laminated layers of the reinforced composite sheet and the thermoplastic elastomer composition foam sheet is greater than or equal to 3 layers; and / or, The thermoplastic elastomer composition foamed sheets are stacked in order from top to bottom at an angle of 0-90 degrees along their respective machine directions; and / or, The reinforced composite sheets are stacked in sequence from top to bottom at an angle of 0-90 degrees along their respective machine directions.

33. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: Based on the total thickness of the multi-layer reinforced composite foam sheet, the total thickness of the reinforced composite sheet accounts for 4%-15.5% of the total thickness of the multi-layer reinforced composite foam sheet; and / or, the number of laminated layers of the reinforced composite sheet and the thermoplastic elastomer composition foam sheet is 3-100 layers; and / or, The thermoplastic elastomer composition foamed sheets are stacked in layers from top to bottom at an angle of 0-90 degrees along their respective machine directions, with the number of layers being greater than or equal to 1; and / or, The reinforced composite sheets are stacked in order from top to bottom at an angle of 0-90 degrees along their respective machine directions, and the total number of layers of polypropylene sheets and polypropylene fabrics in each layer of the reinforced composite sheet is greater than or equal to 2 layers.

34. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The number of laminated layers of the reinforced composite sheet and the thermoplastic elastomer composition foamed sheet is 6-60; and / or, The thermoplastic elastomer composition foamed sheets are stacked in layers from top to bottom at an angle of 0-90 degrees along their respective machine directions, with 1 to 10 layers; and / or, The reinforced composite sheets are stacked in sequence from top to bottom at an angle of 0-90 degrees along respective machine directions, and the total number of polypropylene sheets and polypropylene fabrics in each layer of the reinforced composite sheet is 2-100 layers.

35. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The thermoplastic elastomer composition foamed sheets are stacked in layers from top to bottom at an angle of 0-90 degrees along their respective machine directions, with 2-5 layers; and / or, The reinforced composite sheets are stacked in sequence from top to bottom at an angle of 0-90 degrees along respective machine directions, and the total number of polypropylene sheets and polypropylene fabrics in each layer of the reinforced composite sheet is 4-40 layers.

36. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The density of the thermoplastic elastomer composition foamed sheet is 0.01-0.5 g / L.

37. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The density of the thermoplastic elastomer composition foamed sheet is 0.1-0.4 g / L.

38. The multi-layer reinforced composite foam sheet according to any one of claims 1 to 25, characterized in that: The thermoplastic elastomer composition foamed sheet contains a polyolefin thermoplastic elastomer composition, and the polyolefin thermoplastic elastomer composition contains POE, EVA and optional auxiliary agents.

39. The multi-layer reinforced composite foam sheet according to claim 38, characterized in that: In parts by weight, based on the total weight of POE and EVA being 100 parts by weight, the content of the POE is 5 to 50 parts by weight, and the total amount of the EVA is 50 to 95 parts by weight.

40. The multi-layer reinforced composite foam sheet according to claim 38, characterized in that: The auxiliary agent is selected from a cross-linking agent, a foaming agent, stearic acid, zinc stearate, zinc oxide, a filler and maleic anhydride copolymer microspheres.

41. The multi-layer reinforced composite foam sheet according to claim 40, characterized in that: In parts by weight, relative to 100 parts by total weight of POE and EVA, the content of the crosslinking agent is 0.1 to 1 part by weight; the content of the foaming agent is 0.1 to 10 parts by weight; the content of the stearic acid is 0.1 to 1 part by weight; the content of the zinc stearate is 0.1 to 1 part by weight; the content of the zinc oxide is 0.1 to 10 parts by weight; the content of the filler is 1 to 40 parts by weight; and the content of the maleic anhydride copolymer microspheres is 0.1 to 5 parts by weight.

42. The multi-layer reinforced composite foam sheet according to claim 40, characterized in that: In parts by weight, relative to 100 parts by total weight of POE and EVA, the content of the cross-linking agent is 0.3 to 0.8 parts by weight; the content of the foaming agent is 2 to 7 parts by weight; the content of the stearic acid is 0.2 to 0.5 parts by weight; the content of the zinc stearate is 0.2 to 0.5 parts by weight; the content of the zinc oxide is 0.5 to 2 parts by weight; the content of the filler is 5 to 30 parts by weight; and the content of the maleic anhydride copolymer microspheres is 0.2 to 1 part by weight.

43. A method for preparing the multi-layer reinforced composite foam sheet according to any one of claims 1 to 42, comprising laminating the polypropylene sheet and / or the polypropylene fabric with the thermoplastic elastomer composition foam sheet, fusing them by hot pressing, and then cooling and shaping to obtain the multi-layer reinforced composite foam sheet; or, comprising first laminating the polypropylene sheet and / or the polypropylene fabric, fusing them by hot pressing to obtain a reinforced composite sheet; and then laminating the reinforced composite sheet with the thermoplastic elastomer composition foam sheet, fusing them at 60-80°C to obtain the multi-layer reinforced composite foam sheet.

44. The preparation method according to claim 43, characterized in that: The polypropylene sheets and / or the polypropylene fabrics are stacked in order to form corresponding layers of reinforced composite sheets.

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

46. ​​The preparation method according to claim 43, characterized in that: The conditions for the hot pressing fusion include: The hot pressing temperature is 115-159° C.; and / or the hot pressing pressure is 2-10 MPa, the preheating time is 5-600 s, and the hot pressing time is 10-500 s.

47. The preparation method according to claim 43, characterized in that: The conditions for the hot pressing fusion include: The hot pressing temperature is 140-159℃.

48. Application of the multi-layer reinforced composite foam sheet according to any one of claims 1 to 42 or the multi-layer reinforced composite foam sheet prepared by the preparation method according to any one of claims 43 to 47 in the fields of automobiles, communications, aircraft, logistics, thermal insulation, precision machinery and electronic turnover, and packaging.

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