Non-woven composite material, preparation method thereof and application of non-woven composite material in fresh surface liquid adsorption

Abstract

The invention belongs to the technical field of adsorption materials, and particularly relates to a non-woven composite material, a preparation method of the non-woven composite material and application of the non-woven composite material in fresh surface liquid adsorption. The non-woven composite material is of a multi-layer structure and is composed of at least three layers of structures, the upper non-woven fiber net layer is of a porous structure, and the flow guiding and blocking effects are achieved; the core body layer is of an absorption structure and plays a role in absorption and storage; meanwhile, the preparation raw materials of the core body layer at least comprise wood pulp fibers and / or super absorbent resin particles, so that the liquid absorption and storage capacity of the non-woven composite material is remarkably improved; the lower non-woven fiber net layer is compact in fiber distance and plays a liquid blocking role. The non-woven composite material provided by the invention is used for fresh products, can absorb and fix liquid, and can effectively adsorb the liquid on the surfaces of the fresh products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of adsorption materials, and particularly relates to a non-woven composite material, a preparation method thereof and application thereof in liquid adsorption on the surface of fresh food. BACKGROUND

[0002] When transporting fresh food, a water absorption pad is needed to be placed in a fresh food box, and then the fresh food is placed on the surface of the water absorption pad to achieve the purpose of water absorption. The existing fresh water absorption paper is generally prepared by a hydroentangling process of wood pulp and polypropylene fibers. The wood pulp exists on the surface of the product and directly contacts and rubs with the wiped object. Since the wood pulp fibers are short and the entanglement strength is low, the wood pulp fibers are prone to fall off. In addition, a glue-free dust paper is used as the fresh water absorption paper. Since the glue-free dust paper contains an adhesive, although the falling-off phenomenon is obviously improved, the adhesive may leave formaldehyde or other small molecule chemical substances, which poses a hidden danger in safety. Meanwhile, the absorption efficiency is low and the solid-liquid capacity is poor. SUMMARY

[0003] The present application aims to provide a non-woven composite material, a preparation method thereof and application thereof in liquid adsorption on the surface of fresh food. The non-woven composite material provided by the present application has a significant liquid absorption and fixation capacity and can effectively adsorb the liquid on the surface of fresh food.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: The present application provides a non-woven composite material, which comprises, from bottom to top, a lower non-woven fiber web layer, an intermediate layer and an upper non-woven fiber web layer arranged in layers. The average pore size of the lower non-woven fiber web layer is < the average pore size of the upper non-woven fiber web layer. The raw materials for preparing the lower non-woven fiber web layer and the upper non-woven fiber web layer comprise a thermoplastic polymer and a functional additive. The functional additive comprises a functional master batch and / or a functional additive agent. The intermediate layer comprises at least one core layer. The raw materials for preparing the core layer comprise at least wood pulp fibers and / or superabsorbent resin particles.

[0005] Preferably, the lower non-woven fiber web layer has a grammage of 5-20 gsm, an average fiber diameter of 1-5 μm, an average pore size of 1-7.5 μm and an air permeability of 0-500 mm / s, and the air permeability is not 0. The upper non-woven fiber web layer has a grammage of 1.5-9 gsm, an average fiber diameter of 1-20 μm, an average pore size of 6-15 μm and an air permeability of 500-2000 mm / s.

[0006] Preferably, the raw materials for preparing the core layer further comprise a thermoplastic polymer. The core layer has 1-2 layers.

[0007] Preferably, the gram weight of the core layer is 13.5-113 gsm.

[0008] Preferably, the intermediate layer further comprises at least one intermediate nonwoven web layer, the intermediate nonwoven web layer is not in contact with the lower nonwoven web layer, and is not in contact with the upper nonwoven web layer, the average pore size of the intermediate nonwoven web layer is greater than the average pore size of the lower nonwoven web layer. The raw material for preparing the intermediate nonwoven web layer comprises a thermoplastic polymer and a functional additive, the functional additive comprises a functional master batch and / or a functional auxiliary agent.

[0009] Preferably, the gram weight of the intermediate nonwoven web layer is 2.5-3.5 gsm, the average fiber diameter is 3.5-4.2 μm, and the average pore size is 9-11 μm.

[0010] Preferably, the thermoplastic polymer comprises one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer, and ethylene-vinyl acetate copolymer. The functional master batch comprises one or more of hydrophilic master batch, biodegradable master batch, soft master batch, and antibacterial master batch. The functional auxiliary agent comprises a hydrophilic auxiliary agent. The wood pulp fiber comprises coniferous pulp and / or broadleaf pulp. The superabsorbent resin particles are prepared by a belt method, a kettle method, or a reverse phase suspension method.

[0011] The present application provides a preparation method of the nonwoven composite material as described above, comprising the following steps: Preparation of the lower nonwoven web layer on a webbing curtain; Preparation of the intermediate layer on the lower nonwoven web layer, the intermediate layer comprising at least one core layer; Preparation of the upper nonwoven web layer on the intermediate layer to obtain a multi-layer structure product; Hot rolling treatment of the multi-layer structure product to obtain the nonwoven composite material.

[0012] Preferably, the preparation conditions of the lower nonwoven fiber layer comprise: a melt temperature of 200-280℃, a drawing air temperature of 200-280℃, a drawing air volume of 0-5000 m 3 / h, and not 0, a metering pump screw rotation speed of 0-80 rpm, and not 0; The preparation conditions of the upper nonwoven web layer comprise: a melt temperature of 200-280℃, a drawing air temperature of 200-280℃, a drawing air volume of 0-5000 m 3 / h, and not 0, the metering pump screw speed is 0~80rpm, and not 0.

[0013] This invention provides the application of the nonwoven composite material described in the above technical solution or the nonwoven composite material prepared by the preparation method described in the above technical solution in the adsorption of liquid on the surface of fresh food.

[0014] This invention provides a nonwoven composite material comprising, from bottom to top, a lower nonwoven fiber web layer, an intermediate layer, and an upper nonwoven fiber web layer stacked together; the average pore size of the lower nonwoven fiber web layer is less than the average pore size of the upper nonwoven fiber web layer; the raw materials for preparing the lower and upper nonwoven fiber web layers include thermoplastic polymers and functional additives, the functional additives including functional masterbatches and / or functional auxiliaries; the intermediate layer includes at least one core layer, the raw materials for preparing the core layer including at least wood pulp fibers and / or superabsorbent polymer (SAP) particles. The nonwoven composite material provided by this invention has a multi-layer structure, consisting of at least three layers. This invention optimizes the average pore size relationship between the upper and lower nonwoven fiber web layers. The upper nonwoven fiber web layer has a porous structure, serving both as a guide and barrier; the core layer has an absorbent structure, serving as an absorbent and storage layer; simultaneously, the raw materials for preparing the core layer include at least wood pulp fiber and / or superabsorbent resin particles, significantly improving the liquid absorption and storage capacity of the nonwoven composite material; the lower nonwoven fiber web layer has a smaller average pore size and denser fiber spacing, serving as a liquid barrier. The nonwoven composite material provided by this invention can absorb and fix liquids in fresh produce, effectively adsorbing liquids from the surface of fresh produce.

[0015] Furthermore, in this invention, the intermediate layer further includes at least one intermediate nonwoven fiber web layer. This intermediate nonwoven fiber web layer does not contact the lower nonwoven fiber web layer, nor does it contact the upper nonwoven fiber web layer. The average pore size of the intermediate nonwoven fiber web layer is greater than the average pore size of the lower nonwoven fiber web layer. This invention, through the intermediate nonwoven fiber web layer, can provide more support and restraint to the core layers in the intermediate layer, improving the poor structural stability of multiple core layers in high-basis-weight nonwoven composite materials, and addressing the overflow of wood pulp and / or SAP. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the nonwoven composite material prepared in Example 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the nonwoven composite material prepared in Example 2 of the present invention; Figure 3 This is a schematic diagram of the structure of the nonwoven composite material prepared in Example 3 of the present invention; Figure 4This is a schematic diagram of the structure of the nonwoven composite material prepared in Example 4 of the present invention; Figure 5 This is a schematic diagram of an apparatus for preparing nonwoven composite materials provided by the present invention. Detailed Implementation

[0017] This invention provides a nonwoven composite material comprising, from bottom to top, a lower nonwoven fiber web layer, an intermediate layer, and an upper nonwoven fiber web layer stacked together; the average pore size of the lower nonwoven fiber web layer is less than the average pore size of the upper nonwoven fiber web layer; the raw materials for preparing the lower and upper nonwoven fiber web layers include thermoplastic polymers and functional additives, the functional additives including functional masterbatches and / or functional auxiliaries; the intermediate layer includes at least one core layer, the raw materials for preparing the core layer including at least wood pulp fibers and / or superabsorbent resin particles.

[0018] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0019] The nonwoven composite material provided by this invention includes a lower nonwoven fiber web layer. In this invention, the average pore size of the lower nonwoven fiber web layer is less than the average pore size of the upper nonwoven fiber web layer. The basis weight of the lower nonwoven fiber web layer is preferably 5~20 gsm, more preferably 5~7.5 gsm, and in embodiments it can be 7 gsm, 7.2 gsm or 5.74 gsm. The average fiber diameter of the lower nonwoven fiber web layer is preferably 1~5 μm, more preferably 2~3 μm, and in embodiments it can be 2.25 μm, 2.71 μm, 2.51 μm or 2.34 μm. The average pore size of the lower nonwoven fiber web layer is preferably 1~7.5 μm, more preferably 5.5~7.5 μm, and in embodiments it can be 6.05 μm, 7.21 μm, 5.78 μm or 6.88 μm. The air permeability of the lower nonwoven fiber web layer is preferably 0~500mm / s, and not 0.

[0020] In this invention, the raw materials for preparing the lower nonwoven fiber web layer include thermoplastic polymers and functional additives, wherein the functional additives include functional masterbatches and / or functional auxiliaries. The thermoplastic polymer preferably includes one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer, and ethylene-vinyl acetate copolymer; in the examples, it can be polypropylene. The functional masterbatch preferably includes one or more of hydrophilic masterbatch, biodegradable masterbatch, soft masterbatch, and antibacterial masterbatch. The antibacterial masterbatch can be a silver ion antibacterial masterbatch. The functional auxiliaries preferably include hydrophilic auxiliaries. The mass ratio of the thermoplastic polymer to the functional additive is preferably 98~99:1~2; in the examples, it can be 98:2 or 99:1.

[0021] The nonwoven composite material provided by the present invention includes an intermediate layer stacked on the upper surface of the lower nonwoven fiber web layer. The intermediate layer includes at least one core layer, and the raw materials for preparing the core layer include at least wood pulp fibers and / or superabsorbent resin particles.

[0022] In this invention, the raw materials for preparing the core layer can be wood pulp fibers and / or superabsorbent polymer (SAP) particles. The wood pulp fibers preferably include softwood pulp and / or hardwood pulp. The superabsorbent polymer particles are preferably prepared by a belt process, a batch process, or a reverse-phase suspension process. In this embodiment of the invention, the superabsorbent polymer particles were purchased from Shandong Nuoer Technology Co., Ltd.: model NR-511.

[0023] In this invention, the raw materials for preparing the core layer preferably include wood pulp fibers and superabsorbent resin particles, or include wood pulp fibers.

[0024] In this invention, the raw materials for preparing the core layer may further include thermoplastic polymers. The thermoplastic polymers preferably include one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer, and ethylene-vinyl acetate copolymer.

[0025] In this invention, the raw materials for preparing the core layer are preferably wood pulp fiber, superabsorbent resin particles and thermoplastic polymer. The mass ratio of the wood pulp fiber, superabsorbent resin particles and thermoplastic polymer is preferably 0~100:0~100:20~100, and none of them are 0. More preferably, it is (10~50):(20~80):(20~60). In the embodiment, it can be 25:50:25.

[0026] In this invention, the raw materials for preparing the core layer are preferably wood pulp fiber and thermoplastic polymer. The mass ratio of the wood pulp fiber to the thermoplastic polymer is preferably 0~100:20~100, and is not 0. More preferably, it is (50~80):(30~50). In the embodiments, it can be 67.5:32.5, 60:40 or 65:35.

[0027] In this invention, the raw material for preparing the core layer can be SAP.

[0028] In this invention, the core layer is preferably one or two layers.

[0029] In this invention, the basis weight of a core layer is preferably 13.5~113 gsm, more preferably 40~90 gsm, and in the embodiments it can be 90 gsm, 70 gsm, 30 gsm, 80 gsm, 73 gsm or 40.52 gsm.

[0030] In this invention, the intermediate layer may further include at least one intermediate nonwoven fiber web layer. In the embodiments, the intermediate nonwoven fiber web layer may be one or two layers. Multiple intermediate nonwoven fiber web layers are separated by a core layer. The intermediate nonwoven fiber web layer does not contact the lower nonwoven fiber web layer, nor does it contact the upper nonwoven fiber web layer. The average pore size of the intermediate nonwoven fiber web layer is greater than the average pore size of the lower nonwoven fiber web layer.

[0031] In this invention, the basis weight of the intermediate nonwoven fiber web layer is preferably 2.5~3.5 gsm, and in the embodiments it can be 2.8 gsm or 3.5 gsm. The average fiber diameter of the intermediate nonwoven fiber web layer is preferably 3.5~4.2 μm, and in the embodiments it can be 3.88 μm or 4.08 μm. The average pore size is preferably 9~11 μm, and in the embodiments it can be 9.05 μm or 10.65 μm.

[0032] In this invention, the raw materials for preparing the intermediate nonwoven fiber web layer include thermoplastic polymers and functional additives, wherein the functional additives include functional masterbatches and / or functional auxiliaries. The thermoplastic polymer preferably includes one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer, and ethylene-vinyl acetate copolymer. The functional masterbatch preferably includes one or more of hydrophilic masterbatch, biodegradable masterbatch, flexible masterbatch, and antibacterial masterbatch. The antibacterial masterbatch can be a silver ion antibacterial masterbatch. The functional auxiliaries preferably include hydrophilic auxiliaries. The mass ratio of the thermoplastic polymer to the functional additive is 98~99:1~2.

[0033] The nonwoven composite material provided by this invention includes an upper nonwoven fiber web layer stacked on the upper surface of the intermediate layer. In this invention, the basis weight of the upper nonwoven fiber web layer is preferably 1.5~9 gsm, more preferably 3~4 gsm, and in embodiments, it can be 3 gsm, 3.5 gsm, or 3.74 gsm. The average fiber diameter of the upper nonwoven fiber web layer is preferably 1~20 μm, more preferably 4~4.5 μm, and in embodiments, it can be 4.11 μm, 4.08 μm, 4.36 μm, or 4.34 μm. The average pore size of the upper nonwoven fiber web layer is preferably 6~15 μm, more preferably 10~11.5 μm, and in embodiments, it can be 11.05 μm, 10.68 μm, 11.21 μm, or 11.31 μm. The air permeability of the upper nonwoven fiber web layer is preferably in the range of 500~2000 mm / s.

[0034] In this invention, the raw materials for preparing the upper nonwoven fiber web layer include thermoplastic polymers and functional additives, wherein the functional additives include functional masterbatches and / or functional auxiliaries. The thermoplastic polymer preferably includes one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer, and ethylene-vinyl acetate copolymer; in the examples, it can be polypropylene. The functional masterbatch preferably includes one or more of hydrophilic masterbatch, biodegradable masterbatch, soft masterbatch, and antibacterial masterbatch. The antibacterial masterbatch can be a silver ion antibacterial masterbatch. The functional auxiliaries preferably include hydrophilic auxiliaries. The mass ratio of the thermoplastic polymer to the functional additive is preferably 98~99:1~2; in the examples, it can be 98:2 or 99:1.

[0035] The total basis weight of the nonwoven composite material provided by the present invention is preferably 30~250 gsm, and in the examples it can be 100 gsm.

[0036] This invention provides a method for preparing the nonwoven composite material described in the above technical solution, comprising the following steps: Prepare a lower nonwoven fiber web layer on the woven curtain; An intermediate layer is prepared on the lower nonwoven fiber web layer, the intermediate layer comprising at least one core layer; An upper nonwoven fiber web layer is prepared on the intermediate layer to obtain a multilayer structure product; The multilayer structure product is hot-rolled to obtain the nonwoven composite material.

[0037] This invention prepares a lower nonwoven fiber web layer on a fabricated screen. In this invention, the lower nonwoven fiber web layer serves as a liquid barrier layer. By adjusting process parameters such as melt temperature and hot air volume in the polymer spinning web-forming process, the fiber diameter is reduced to decrease fiber gaps. Alternatively, the screw speed of the metering pump can be adjusted to increase the basis weight of the nonwoven fiber web layer, resulting in a dense layer where blood, moisture, and other liquids from fresh produce are trapped within the composite material, preventing direct contact with the external environment and thus avoiding the growth of microorganisms and pathogens.

[0038] In this invention, the method for preparing the lower nonwoven fiber web layer preferably includes an air-blowing web forming method or a spunbond web forming method, specifically air-blowing web forming, melt-blowing web forming, or spunbond web forming.

[0039] In a specific embodiment of the present invention, the preferred method for preparing the lower nonwoven fiber web layer includes: feeding a thermoplastic raw material into a polymer feeding system; melting, mixing, and quantitatively conveying the raw material to a first set of thermoplastic fiber spinning components for extrusion into a melt; then drawing it into filaments under the action of a high-speed, high-temperature airflow; and finally laying it onto a forming curtain under the action of suction at the bottom of the mesh to form the lower nonwoven fiber web layer. In the present invention, the preferred preparation conditions for the lower nonwoven fiber layer include: the melt temperature is preferably 200~280℃, and in the embodiments, it can be 220℃, 235℃, or 230℃. The drawing air temperature is preferably 200~280℃, and in the embodiments, it can be 225℃, 240℃, or 235℃. The drawing air volume is preferably 0~5000m³ / h. 3 / h, and not 0; in the example, it can be 2200m. 3 / h, 3700m 3 / h, 3000m 3 / h or 3500m 3 / h. The preferred screw speed of the metering pump is 0~80 rpm, and not 0. In the examples, it can be 18 rpm, 27 rpm or 26 rpm.

[0040] After obtaining the lower nonwoven fiber web layer, the present invention prepares an intermediate layer on the lower nonwoven fiber web layer, the intermediate layer comprising at least one core layer. In the present invention, the core layer is preferably obtained by polymer spinning combined with airflow spinning, in which thermoplastic polymers, wood pulp fibers and / or SAP are thoroughly entangled and mixed.

[0041] In this embodiment of the invention, the core layer is preferably formed by polymer spinning web combined with airflow web forming. Thermoplastic polymer and functional masterbatch are formed into fibers by spinning device, and then fully entangled and mixed with defiberized wood pulp fibers and superabsorbent polymer (SAP) particles.

[0042] In a specific embodiment of the present invention, the preparation method of the core layer preferably includes: breaking wood pulp fiberboard into single fibers using a crushing device or uniformly distributing mixed SAP material through an airflow distribution device and then dropping it through a pipe; simultaneously, the thermoplastic fibers of the intermediate core layer are melted, mixed, and quantitatively conveyed to a third set of thermoplastic fiber spinning components for extrusion into a melt, which is then drawn into filaments under the action of a high-speed, high-temperature airflow. During the extrusion process, the filaments are fully entangled and mixed with the wood pulp fibers and SAP spread in the pipe to form the intermediate core layer. The preferred preparation conditions for the core layer include: the melt temperature is preferably 200~280℃, and in this embodiment, it can be 220℃; the drawing air temperature is preferably 200~280℃, and in this embodiment, it can be 225℃; and the drawing air volume is preferably 0~7000m³. 3 / h, and not 0; in the example, it can be 3500m. 3 / h, 4500m 3 / h or 4400m 3 / h. The metering pump screw speed is 0~80 rpm, and not 0; in the embodiment, it can be 28 rpm or 30 rpm. In this invention, because the core layer absorbent material has a large basis weight, more thermoplastic fibers are needed to bond with it to stabilize the layer structure and reduce the overflow of materials such as wood pulp; therefore, a larger metering pump screw speed is used.

[0043] In this invention, when the intermediate layer comprises an intermediate nonwoven fiber web layer, the preferred conditions for preparing the intermediate nonwoven fiber web layer include: the melt temperature is preferably 200~280℃, and in the embodiment, it can be 225℃; the drawing air temperature is preferably 200~280℃, and in the embodiment, it can be 220℃ or 225℃; the drawing air volume is preferably 0~5000m³. 3 / h, and not 0; in the example, it can be 2000m. 3 / h、2200m 3 / h, 2500m 3 / h, 2300m 3 / h. The preferred screw speed of the metering pump is 0~80 rpm, and not 0. In the examples, it can be 8 rpm, 12 rpm, 9 rpm or 17 rpm.

[0044] After obtaining the intermediate layer, the present invention prepares an upper nonwoven fiber web layer on the intermediate layer to obtain a multilayer structure product.

[0045] In this invention, the upper nonwoven fiber web layer is the contact surface for fresh produce. This invention increases the fiber diameter by adjusting process parameters such as melt temperature and hot air volume in the polymer spinning web forming process, thereby increasing the fiber gaps. Alternatively, it decreases the basis weight of the nonwoven fiber web layer by adjusting the screw speed of the metering pump, resulting in sparse fiber stacking and the formation of a porous layer. This allows liquids such as blood and water from fresh produce to pass smoothly through the gaps and enter the middle core layer.

[0046] In this invention, the method for preparing the upper nonwoven fiber web layer preferably includes an air-blowing web forming method or a spunbond method, specifically air-blowing web forming, melt-blowing web forming, or spunbond web forming.

[0047] In a specific embodiment of the present invention, the preferred method for preparing the upper nonwoven fiber web layer includes: feeding a thermoplastic raw material into a polymer feeding system; melting, mixing, and quantitatively conveying the raw material to a second set of thermoplastic fiber spinning components for extrusion into a melt; then drawing it into filaments under the action of a high-speed, high-temperature airflow; and finally, laying it onto a forming curtain under the action of suction at the bottom of the mesh to form the upper nonwoven fiber web layer. In the present invention, the preferred preparation conditions for the upper nonwoven fiber web layer include: the melt temperature is preferably 200~280℃, and in the embodiment, it can be 220℃ or 225℃; the drawing air temperature is preferably 200~280℃, and in the embodiment, it can be 220℃ or 225℃; and the drawing air volume is preferably 0~5000m³. 3 / h, and not 0; in the example, it can be 2000m. 3 / h, 2500m 3 / h, 2500m 3 / h or 2300m 3 / h. The preferred screw speed of the metering pump is 0~80 rpm, and not 0. In the examples, it can be 8 rpm, 12 rpm, 9 rpm or 17 rpm.

[0048] In a specific embodiment of the present invention, the metering pump screw speed during the preparation of the upper nonwoven fiber web is lower than that during the preparation of the lower nonwoven fiber web. Since the metering pump speed directly affects the web weight and fiber diameter, it indirectly affects the web-laying degree; the lower nonwoven fiber web has a faster metering pump screw speed, smaller fiber diameter, denser fiber packing, smaller gaps, and a smaller average pore size.

[0049] After obtaining the multi-layered product, the present invention performs hot rolling on the multi-layered product to obtain the nonwoven composite material. In the present invention, the multi-layered product is conveyed to a hot rolling mill by a web forming curtain for hot rolling. The conveying speed is preferably 160~280m / min, and in the embodiments, it can be 280m / min, 160m / min, or 240m / min. The hot rolling process is preferably carried out in a hot rolling device, which preferably includes patterned hot rolls, smooth hot rolls, and cooling rolls. The temperature of the patterned hot rolls and smooth hot rolls is preferably 90~160℃. In the embodiments, the temperature of the patterned hot rolls can be 110℃ or 120℃, and the temperature of the smooth hot rolls can be 105℃ or 100℃. The cooling rolls can be unheated rolls or rolls with cooling process water flowing inside. The temperature of the cooling process water is preferably 15~25℃. The number of hot rolls is preferably one patterned hot roll and one smooth hot roll, and the number of cooling rolls is not limited. The patterned hot roller and the smooth hot roller are positioned vertically, and their vertical positions are not restricted. The lower nonwoven fiber web layer can be directly contacted with the patterned hot roller by adjusting the fabric threading method. After the hot rolling process is completed, the present invention preferably further includes sequentially passing the product through an online defect detection device for appearance defects and weight uniformity detection, a slitting and winding device for slitting and winding, and an automatic conveying and packaging device for automated packaging, to obtain the finished nonwoven composite material.

[0050] This invention provides the application of the nonwoven composite material described in the above technical solution or the nonwoven composite material prepared by the preparation method described in the above technical solution in the adsorption of liquid on the surface of fresh food.

[0051] In this invention, the nonwoven composite material is preferably used as the absorbent pad for fresh produce.

[0052] The nonwoven composite material provided by this invention uses thermoplastic hydrophobic materials for both the lower and upper nonwoven fiber web layers to reduce liquid absorption before re-contacting fresh products. The lower nonwoven fiber web layer achieves a dense, gap-like structure to isolate liquid through a melt-spun process. This invention can also achieve rapid water absorption through hydrophilic modification of the lower and upper nonwoven fiber web layers. Furthermore, by adding antibacterial masterbatch during the preparation of both layers, a long-lasting antibacterial effect can be effectively achieved.

[0053] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1: This embodiment provides a nonwoven composite material for absorbent use in fresh produce, such as... Figure 1 As shown, from bottom to top, the layers are a lower nonwoven fiber web, an intermediate core layer, and an upper nonwoven fiber web. The preparation steps are as follows: (1) Polypropylene and silver ion antibacterial masterbatch are fed into the polymer feeding system at a mass ratio of 98:2. After a series of melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the first thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments and then laid onto the forming curtain under the action of suction at the bottom of the net to form the lower nonwoven fiber web layer. The melt temperature is 235℃, the drawing air temperature is 240℃, and the drawing air volume is 3700 m³ / h. 3 / h, metering pump screw speed is 18rpm, basis weight is 7gsm, average fiber diameter is 2.25μm, and average pore size is 6.05μm.

[0055] (2) The wood pulp fiberboard is broken down into single fibers by a crushing device. The mixed SAP material is evenly distributed by an airflow distribution device and falls from the pipe. At the same time, the thermoplastic fiber (polypropylene) of the intermediate core layer is melted, mixed, and quantitatively transported to the third set of thermoplastic fiber spinning components and extruded into a melt. Then, it is drawn into filaments under the action of high-speed and high-temperature airflow. During the spraying process, it is fully entangled and mixed with the wood pulp fiber and SAP spread in the pipe. The mass ratio of wood pulp fiber, SAP and polypropylene is 25:50:25 to form the intermediate core layer. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 3500m³. 3 / h, the metering pump screw speed is 28rpm, and the weight is 90gsm.

[0056] (3) Polypropylene and silver ion antibacterial masterbatch are fed into the polymer feeding system at a mass ratio of 98:2. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the second thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments and laid onto the intermediate core layer to form the upper nonwoven fiber web layer. The melt temperature is 225℃, the drawing air temperature is 220℃, and the drawing air volume is 2500 m³ / h. 3 / h, metering pump screw speed is 8rpm, basis weight is 3gsm, average fiber diameter is 4.11μm, and average pore size is 11.05μm; (4) The above material is conveyed through the hot rolling device at a speed of 160 m / min. The temperature of the patterned hot roller is 110°C and the temperature of the smooth hot roller is 105°C. After hot rolling, it becomes a 100 gsm nonwoven composite absorbent pad material.

[0057] Example 2: This embodiment provides a nonwoven composite material for absorbent pads used for fresh produce, such as... Figure 2 As shown, from bottom to top, the layers are a lower nonwoven fiber web, a first intermediate core layer, a second intermediate core layer, and an upper nonwoven fiber web. The preparation steps are as follows: (1) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After a series of melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the first thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments and then laid onto the forming curtain under the action of suction at the bottom of the net to form the lower nonwoven fiber web layer. The melt temperature is 230℃, the drawing air temperature is 235℃, and the drawing air volume is 3000m³. 3 / h, metering pump screw speed is 27rpm, basis weight is 7gsm, average fiber diameter is 2.71μm, and average pore size is 7.21μm.

[0058] (2) The wood pulp fiberboard is broken down into single fibers by a crushing device, and then evenly distributed by an airflow distribution device before falling through a pipe. At the same time, the thermoplastic fibers (polypropylene) of the first intermediate core layer are melted, mixed, and quantitatively transported to the third set of thermoplastic fiber spinning components and extruded into a melt. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments. During the spraying process, it is fully entangled and mixed with the wood pulp fibers spread in the pipe. The mass ratio of wood pulp fibers to polypropylene is 67.5:32.5, forming the first intermediate core layer. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 4400m³. 3 / h, the metering pump screw speed is 30rpm, and the weight is 70gsm.

[0059] (3) The SAP material is evenly distributed through the airflow distribution device and then falls from the pipe onto the first intermediate core layer to form the second intermediate core layer with a basis weight of 30 gsm.

[0060] (4) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the second thermoplastic fiber spinning assembly. Then, under the action of high-speed, high-temperature airflow, it is drawn into filaments and laid on the second intermediate core layer to form the upper nonwoven fiber web layer. The melt temperature is 225°C, the drawing air temperature is 225°C, and the drawing air volume is 2300 m³ / h. 3 / h, metering pump screw speed is 12rpm, single layer basis weight is 3gsm, average fiber diameter is 4.08μm, and average pore size is 10.68μm.

[0061] (5) The above material is conveyed through the hot rolling device at a speed of 240 m / min. The temperature of the patterned hot roller is 120°C and the temperature of the smooth hot roller is 100°C. After hot rolling, it becomes a 110 gsm nonwoven composite absorbent pad material.

[0062] Example 3: This embodiment provides a nonwoven composite material for absorbent pads used for fresh produce, such as... Figure 3 As shown, from bottom to top, the layers are: lower nonwoven fiber web layer, first intermediate core layer, first intermediate nonwoven fiber web layer, second intermediate nonwoven fiber web layer, second intermediate core layer, and upper nonwoven fiber web layer. The preparation steps are as follows: (1) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After a series of melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the first thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments. Finally, under the action of suction at the bottom of the mesh, it is laid onto the forming curtain to form a dense lower nonwoven fiber web. The melt temperature is 235℃, the drawing air temperature is 235℃, and the drawing air volume is 3500 m³ / h.3 / h, metering pump screw speed is 18rpm, single layer basis weight is 7.2gsm, average fiber diameter is 2.51μm, and average pore size is 5.78μm; (2) The wood pulp fiberboard is broken down into single fibers by a crushing device, and then evenly distributed by an airflow distribution device before falling through a pipe. At the same time, the thermoplastic fibers (polypropylene) of the first intermediate core layer are melted, mixed, and quantitatively transported to the second set of thermoplastic fiber spinning components and extruded into a melt. Then, under the action of high-speed and high-temperature airflow, the melt is drawn into filaments. During the spraying process, the filaments are fully entangled and mixed with the wood pulp fibers spread in the pipe. The mass ratio of wood pulp fibers to polypropylene is 60:40, forming the first intermediate core layer. The melt temperature is 220°C, the drawing air temperature is 225°C, and the drawing air volume is 4400 m³ / h. 3 / h, the metering pump screw speed is 30rpm, and the weight is 80gsm.

[0063] (3) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the third thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments and laid on the first intermediate core layer to form the first intermediate nonwoven fiber web with a porous structure. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 2200 m³ / h. 3 / h, metering pump screw speed is 8rpm, basis weight is 2.8gsm, average fiber diameter is 3.88μm, and average pore size is 9.05μm.

[0064] (4) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the fourth thermoplastic fiber spinning assembly. Then, under the action of high-speed, high-temperature airflow, it is drawn into filaments and laid on the first intermediate nonwoven fiber web to form the second intermediate nonwoven fiber web, which has a porous structure. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 2000 m³ / h. 3 / h, metering pump screw speed is 9rpm, basis weight is 3.5gsm, average fiber diameter is 4.08μm, and average pore size is 10.65μm.

[0065] (5) The wood pulp fiberboard is broken down into single fibers by a crushing device, and then evenly distributed by an airflow distribution device before falling through the pipe. At the same time, the thermoplastic fiber (polypropylene) of the second intermediate core layer is melted, mixed, and quantitatively transported to the fifth group of thermoplastic fiber spinning components and extruded into a melt. Then, it is drawn into filaments under the action of high-speed and high-temperature airflow. During the spraying process, it is fully entangled and mixed with the wood pulp fiber spread in the pipe. The mass ratio of wood pulp fiber to polypropylene is 60:40, forming the second intermediate core layer. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 4400 m³ / h. 3 / h, the metering pump screw speed is 28rpm, and the weight is 73gsm.

[0066] (6) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the sixth thermoplastic fiber spinning assembly. Then, under the action of high-speed and high-temperature airflow, it is drawn into filaments and laid on the second intermediate core layer to form an upper nonwoven fiber web with a porous structure. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 2000 m³ / h. 3 / h, metering pump screw speed is 9rpm, basis weight is 3.5gsm, average fiber diameter is 4.36μm, and average pore size is 11.21μm.

[0067] (4) The above materials are conveyed by the net curtain at a speed of 160m / min through the hot rolling device for composite processing. The temperature of the patterned hot roller is 120℃ and the temperature of the smooth hot roller is 100℃. After hot rolling, it becomes a 170gsm nonwoven composite absorbent pad material.

[0068] In this embodiment, after being composited by a hot rolling device, the two middle porous nonwoven fiber layers can provide more support and restraint for the entire composite material core layer, improving the uneven distribution of the core material in the high-grammage composite material and the overflow of wood pulp / SAP.

[0069] Example 4: This embodiment provides a nonwoven composite material for absorbent paper used in fresh produce, such as... Figure 4 As shown, from bottom to top, the layers are a lower nonwoven fiber web, an intermediate core layer, and an upper nonwoven fiber web. The preparation steps are as follows: (1) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After a series of melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the first thermoplastic fiber spinning assembly. Then, it is drawn into filaments under the action of high-speed and high-temperature airflow, and then laid onto the forming curtain under the action of suction at the bottom of the net to form the lower nonwoven fiber web layer. At the same time as the fiber web is formed, a hydrophilic additive is sprayed. The melt temperature is 230℃, the drawing air temperature is 235℃, and the drawing air volume is 3500m³. 3 / h, metering pump screw speed is 26rpm, basis weight is 5.74gsm, average fiber diameter is 2.34μm, and average pore size is 6.88μm.

[0070] (2) The wood pulp fiberboard is broken down into single fibers by a crushing device, and then evenly distributed by an airflow distribution device before falling through the pipe. At the same time, the thermoplastic fiber (polypropylene) of the intermediate core layer is melted, mixed, and quantitatively transported to the third set of thermoplastic fiber spinning components and extruded into a melt. Then, it is drawn into filaments under the action of high-speed and high-temperature airflow. During the spraying process, it is fully entangled and mixed with the wood pulp fiber spread in the pipe. The mass ratio of wood pulp fiber to polypropylene is 65:35, forming the intermediate core layer. The melt temperature is 220℃, the drawing air temperature is 225℃, and the drawing air volume is 4500m³. 3 / h, the metering pump screw speed is 28rpm, and the weight is 40.52gsm.

[0071] (3) Polypropylene and biodegradable masterbatch are fed into the polymer feeding system at a mass ratio of 99:1. After melting, mixing, and quantitative conveying, the mixture is extruded into a melt at the second thermoplastic fiber spinning assembly. Then, under the action of high-speed, high-temperature airflow, it is drawn into filaments and laid on the intermediate core layer to form the upper nonwoven fiber web layer. At the same time as the fiber web is formed, a hydrophilic additive is sprayed. The melt temperature is 215°C, the drawing air temperature is 220°C, and the drawing air volume is 2100 m³ / h. 3 / h, metering pump screw speed is 17rpm, single layer basis weight is 3.74gsm, average fiber diameter is 4.34μm, and average pore size is 11.31μm.

[0072] (4) The above material is conveyed by a net curtain at a speed of 280 m / min through a hot rolling device. The temperature of the patterned hot roller is 120°C and the temperature of the smooth hot roller is 100°C. After hot rolling, it becomes a 50 gsm nonwoven composite absorbent pad material.

[0073] Test case The products prepared in Examples 1-4 and commercially available products were subjected to performance tests, and the test results are shown in Table 1.

[0074] Table 1. Test results of composite material properties

[0075] Compared with commercially available traditional absorbent paper for fresh produce (made from 70% wood pulp and 30% polypropylene using a hydroentangled process), the absorbency test standard is GB / T26174, and the oil absorption test standard is GB / T24328.6. The absorbency of this implementation case is better than that of traditional absorbent paper for fresh produce.

[0076] As can be seen from the above embodiments, the nonwoven composite material provided by the present invention has a multi-layer structure, consisting of at least three layers. The upper nonwoven fiber web layer has a porous structure, serving as a guide and barrier; the core layer has an absorbent structure, serving as an absorbent and storage layer; simultaneously, the raw materials for preparing the core layer in the present invention include at least wood pulp fiber and / or superabsorbent resin particles, significantly improving the liquid absorption and storage capacity of the nonwoven composite material; the lower nonwoven fiber web layer has dense fiber spacing, serving as a liquid barrier. The nonwoven composite material provided by the present invention can absorb and fix liquids when used in fresh produce, effectively adsorbing liquids from the surface of fresh produce.

[0077] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A nonwoven composite material, characterized by, from bottom to top, comprising a lower nonwoven fiber web layer, an intermediate layer and an upper nonwoven fiber web layer arranged in a stack; the average pore size of the lower nonwoven fiber web layer is < the average pore size of the upper nonwoven fiber web layer, the raw materials for preparing the lower nonwoven fiber web layer and the upper nonwoven fiber web layer comprise a thermoplastic polymer and a functional additive, the functional additive comprises a functional masterbatch and / or a functional auxiliary agent; the intermediate layer comprises at least one core layer, and the raw material for preparing the core layer comprises at least wood pulp fibers and / or superabsorbent resin particles.

2. The nonwoven composite of claim 1, wherein, The lower nonwoven fiber web layer has a grammage of 5-20 gsm, an average fiber diameter of 1-5 μm, an average pore size of 1-7.5 μm, and an air permeability of 0-500 mm / s, and the air permeability is not 0; The upper nonwoven fiber web layer has a grammage of 1.5-9 gsm, an average fiber diameter of 1-20 μm, an average pore size of 6-15 μm, and an air permeability of 500-2000 mm / s.

3. The nonwoven composite of claim 1, wherein, The raw material for preparing the core layer further comprises a thermoplastic polymer; the core layer has a layer number of 1-2 layers.

4. The nonwoven composite of claim 1, wherein, The core layer has a grammage of 13.5-113 gsm.

5. The nonwoven composite of claim 1, wherein, The intermediate layer further comprises at least one intermediate nonwoven fiber web layer, the intermediate nonwoven fiber web layer is not in contact with the lower nonwoven fiber web layer, and is also not in contact with the upper nonwoven fiber web layer, and the average pore size of the intermediate nonwoven fiber web layer is > the average pore size of the lower nonwoven fiber web layer; The raw material for preparing the intermediate nonwoven fiber web layer comprises a thermoplastic polymer and a functional additive, and the functional additive comprises a functional masterbatch and / or a functional auxiliary agent.

6. The nonwoven composite of claim 5, wherein, The intermediate nonwoven fiber web layer has a grammage of 2.5-3.5 gsm, an average fiber diameter of 3.5-4.2 μm, and an average pore size of 9-11 μm.

7. The nonwoven composite of claim 1, wherein, The thermoplastic polymer comprises one or more of polypropylene, polyethylene, polyethylene terephthalate, styrene-butadiene-styrene triblock copolymer and ethylene-vinyl acetate copolymer; The functional masterbatch comprises one or more of hydrophilic masterbatch, biodegradable masterbatch, soft masterbatch and antibacterial masterbatch; The functional auxiliary agent comprises a hydrophilic auxiliary agent; The wood pulp fibers comprise coniferous pulp and / or broadleaf pulp; The superabsorbent resin particles are prepared by a belt method, a kettle method or a reverse-phase suspension method.

8. The method of making a nonwoven composite of any of claims 1-7, characterized in that, The method comprises the following steps: preparing a lower nonwoven fiber web layer on a webbing curtain; preparing an intermediate layer on the lower nonwoven fiber web layer, the intermediate layer comprising at least one core layer; preparing an upper nonwoven fiber web layer on the intermediate layer to obtain a multi-layer structure product; subjecting the multi-layer structure product to hot rolling treatment to obtain the nonwoven composite material.

9. The production method according to claim 8, characterized by, The preparation conditions of the lower nonwoven fiber layer include: melt temperature is 200-280℃, draft air temperature is 200-280℃, draft air volume is 0-5000m 3 / h, and is not 0, metering pump screw rotation speed is 0-80rpm, and is not 0; The preparation conditions of the upper nonwoven fiber web layer include: the melt temperature is 200-280℃, the draft air temperature is 200-280℃, the draft air volume is 0-5000m 3 / h and is not 0, the metering pump screw rotation speed is 0-50rpm and is not 0.

10. Use of the nonwoven composite material according to any one of claims 1-7 or the nonwoven composite material prepared by the preparation method of claim 8 or 9 in absorbing liquid on a fresh food surface.

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