Airdrop TPU water bag composite material and preparation method

Abstract

The present invention relates to the technical field of composite material preparation, and in particular to a novel airdrop TPU water bag composite material and a preparation method, comprising a first TPU layer, a first adhesive layer, a fiber reinforcement layer, a second adhesive layer, and a second TPU layer arranged in sequence from the inside out; the second TPU layer is formed by mixing polyether TPU, a toughening agent, a foaming agent, a flame retardant, an ultraviolet absorber, a promoter, multi-walled carbon nanotubes, and a conductive agent. The second TPU layer composite film of the present invention ultimately presents a plurality of independent bubble structures, so that the TPU film has excellent impact resistance, light weight, explosion resistance and other characteristics. With the help of the impact resistance and mechanical property enhancement effects of the toughening agent and multi-walled carbon nanotubes, and through the mutual assistance of other additives, the film layer has excellent properties such as light weight, environmental protection, wear resistance, flame retardancy, explosion resistance, impact resistance, aging resistance, high and low temperature resistance, and corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and in particular to an airdrop TPU water bag composite material and a preparation method thereof. Background Art

[0002] Currently, airdropped water bladders guarantee water supply needs and are an essential water delivery tool in complex environments, providing a crucial guarantee for combat personnel's survival. Airdropped water bladders of varying sizes play a vital role in diverse environments, such as long-distance transportation, camping, and combat transport. Improving water delivery efficiency is crucial for safeguarding the Army's combat capabilities. Compared to traditional water bladders, airdropped water bladders must be resistant to strong impacts, puncture, high and low temperature, airtight, and maintain water quality; otherwise, they will not be able to achieve their water supply objectives.

[0003] Currently, airdrop water bags often use traditional TPU (thermoplastic polyurethane elastomer) composite materials, such as the following three existing technologies:

[0004] Patent document CN201921946496 discloses a TPU water bag specially used for airdrop disaster relief. The water bag body is composed of a hydrolysis-resistant 0.2mm TPU film from the inside to the outside to form a water bag layer, two 1680 nylon cloths and 0.4mm TPU films are laminated together to clamp the water bag in the center, and two 0.5mm TPU films are blister-formed into multiple independent bubble chambers. One side of the interior of the water bag body is provided with an opening, and a seal is provided at the opening to seal it stably. The TPU water bag used for airdrop disaster relief plays a role in tightly and effectively sealing the opening of the water bag body. At the same time, the inner layer of the water bag body is composed of a hydrolysis-resistant 0.2mm TPU film. This material can be in contact with water for a long time without aging. The nylon cloth is used to increase the product's explosion resistance. Two 0.5mm TPU films are blister-formed into multiple independent bubble chambers. This layer of TPU film has the characteristics of wear resistance and explosion resistance, thereby improving the strength of the water bag body, preventing the water bag from rupturing, and achieving the effect of high-altitude disaster relief.

[0005] Patent document CN201710552564 discloses an ultralight, high-strength, flexible composite membrane and its preparation method. The composite membrane comprises a reinforcement layer and a polymer coating. The reinforcement layer is a fabric containing ultra-high molecular weight polyethylene fibers, and the polymer coating is applied above and / or below the reinforcement layer. This ultralight, high-strength, flexible composite membrane can be widely used in inflatable devices such as inflatable toys and inflatable buildings, liquid storage devices such as oil and water bladders, and waterproof materials such as tents and truck tarpaulins.

[0006] Patent document CN201610192952 discloses a TPU composite fabric for large oil and water bladders. The composite fabric comprises, from top to bottom, a polyester TPU face mask layer, a first adhesive layer, a fiber cloth layer, a second adhesive layer, and a polyether TPU base film layer. The fiber cloth layer has been corona-treated. The present invention modifies the polyester TPU material to create a film made from a blend of EPDM and polycarbodiimide. This film exhibits both strong oil and hydrolysis resistance, and the polyether TPU film further enhances the composite's oil and hydrolysis resistance. Furthermore, the fiber cloth is treated with an electric roller before being bonded with a PUR hot-melt adhesive, enhancing the composite's peel strength. This results in excellent overall performance, making it suitable for use in oil or water bladders.

[0007] Although traditional TPU composite materials have good mechanical properties, impact resistance, water quality, etc., there is still a lot of room for improvement in impact resistance, corrosion resistance, flame retardancy, explosion resistance, water quality and lightweight. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and to propose an airdrop TPU water bag composite material and a preparation method.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] An airdrop TPU water bag composite material comprises a first TPU layer, a first adhesive layer, a fiber reinforcement layer, a second adhesive layer and a second TPU layer arranged in sequence from the inside out;

[0011] The second TPU layer is formed by mixing polyether TPU, a toughening agent, a foaming agent, a flame retardant, an ultraviolet absorber, an accelerator, multi-walled carbon nanotubes and a conductive agent.

[0012] Preferably, the first TPU layer is formed by mixing polyether TPU and an antibacterial agent.

[0013] Preferably, the fiber reinforcement layer is polyethylene and filler.

[0014] Preferably, the second adhesive layer is silicone adhesive.

[0015] Preferably, the first adhesive layer is formed by mixing silicone adhesive, a toughening agent, an accelerator and multi-walled carbon nanotubes.

[0016] Preferably, in the second TPU layer, the mass fraction of toughening agent is 15-20%, the mass fraction of flame retardant is 20%, the mass fraction of ultraviolet absorber is 2-4%, the mass fraction of accelerator is 10-15%, the mass fraction of multi-walled carbon nanotubes is 1-3%, the mass fraction of conductive agent is 1-3%, and the rest is polyether TPU.

[0017] The present invention also discloses a method for preparing an airdrop TPU water bag composite material, comprising the following steps:

[0018] S1. Preparation of the first TPU layer:

[0019] The food-grade antimicrobial agent was placed in an oven at 80°C and dried for 24 hours. It was then added to the food-grade polyether TPU. After mixing, the mixture was melt-blended, extruded and cast into a film using a micro twin-screw extruder to form the first TPU layer.

[0020] S2. Preparation of the second TPU layer:

[0021] Weighing polyether TPU, toughening agent, flame retardant, UV absorber, accelerator, multi-walled carbon nanotubes and conductive agent according to mass ratio, and mixing them evenly in an autoclave to obtain a matured and stable TPU foam bead product;

[0022] The TPU foam beads are melt-extruded and cast through a micro twin-screw extruder to form a second TPU layer;

[0023] S3, bonding and sealing the fiber reinforcement layer, the first TPU layer, and the second TPU layer using silicone adhesive;

[0024] The fiber-reinforced layer and the first TPU layer are bonded and sealed by using a mixture of silicone glue, toughening agent, accelerator and multi-walled carbon nanotubes.

[0025] Preferably, the extrusion temperatures of the three sections of the micro twin-screw in S1 are 170° C., 175° C. and 180° C. respectively.

[0026] Preferably, in S2, after being uniformly mixed in the high-pressure reactor, the cooled and compressed CO2 is continuously and stably introduced in a constant pressure mode.

[0027] Preferably, in S3, in the first adhesive layer, the mass fraction of the toughening agent is 15-20%, the mass fraction of the accelerator is 10-15%, the mass fraction of the multi-walled carbon nanotubes is 1-3%, and the remainder is silicone adhesive.

[0028] The beneficial effects of the present invention are as follows:

[0029] The second TPU layer of the present invention is formed by mixing polyether TPU, a toughening agent, a foaming agent, a flame retardant, an ultraviolet absorber, an accelerator, multi-walled carbon nanotubes, and a conductive agent.

[0030] Among them, polyether TPU and toughening agent have good compatibility and similar processing temperature. When the mass ratio of the two meets the silver shear band toughening mechanism, when encountering impact, the strong intermolecular bonding force of the TPU material itself causes the TPU material to partially agglomerate, forming a "sea-island" structure in the system. At this time, the structure of the flexible chain of the TPU material can act as a stress concentrator, causing a large number of cracks, thereby absorbing a large amount of impact energy and improving the impact strength of the material.

[0031] Multi-walled carbon nanotubes, as nanomaterials, have common characteristics such as a diameter less than 100nm, a large specific surface area, and obvious interface effects; at the same time, carbon nanotubes also have higher axial strength, higher mechanical strength, better biocompatibility, good thermal conductivity, electrical conductivity, high temperature resistance and other physical properties.

[0032] The addition of multi-walled carbon nanotubes can change the microphase separation structure of polyurethane, effectively preventing the migration of small molecules during aging in harsh environments, and has a certain effect on enhancing the mechanical properties and anti-aging properties of TPU in harsh high and low temperature corrosion environments;

[0033] The soft segments of polyether thermoplastic polyurethanes (TPUs) possess excellent flexibility due to their easily rotatable ether groups. Therefore, PPUs facilitate the dissolution and diffusion of blowing agent molecules. Carbon dioxide is a preferred blowing agent for the production of TPU foam beads because it is pollution-free and residue-free, and the resulting beads have a high expansion ratio and excellent performance. Polyurethane foams offer advantages such as low density, high specific strength, and good compatibility with other materials.

[0034] The resulting TPU composite film exhibits a multi-cell structure, resulting in excellent impact resistance, lightweight, and explosion resistance. By leveraging the impact and mechanical properties of toughening agents and multi-walled carbon nanotubes, along with the complementary effects of other additives, the film exhibits exceptional properties such as lightweight, environmental friendliness, wear resistance, flame retardancy, explosion resistance, impact resistance, aging resistance, high and low temperature resistance, and corrosion resistance. DETAILED DESCRIPTION

[0035] The present invention provides an airdrop TPU water bag composite material, comprising a first TPU layer, a first adhesive layer, a fiber reinforcement layer, a second adhesive layer and a second TPU layer arranged in sequence from the inside out;

[0036] The second TPU layer is formed by mixing polyether TPU, a toughening agent, a foaming agent, a flame retardant, an ultraviolet absorber, an accelerator, multi-walled carbon nanotubes and a conductive agent.

[0037] In a preferred embodiment of the present invention, the first TPU layer is formed by mixing polyether TPU and an antimicrobial agent. Both the polyether TPU and the antimicrobial agent are food-grade. Polyether TPU has the following advantages: high resilience, relatively superior insulation properties, good electrical properties, easy processing, resistance to low temperatures, hydrolysis, acid and alkaline corrosion, and strong bacterial resistance, making it a widely used polyurethane elastomer.

[0038] In a preferred embodiment of the present invention, the second TPU layer is formed by mixing polyether TPU, a toughening agent, a foaming agent, a flame retardant, an ultraviolet absorber, an accelerator, multi-walled carbon nanotubes and a conductive agent.

[0039] The material composition of the second TPU layer in this embodiment has the following advantages:

[0040] 1. Polyether TPU and toughening agent have good compatibility and similar processing temperature. When the mass ratio of the two meets the silver shear band toughening mechanism, when encountering impact, the strong intermolecular bonding force of the TPU material itself causes the TPU material to partially agglomerate, forming a "sea-island" structure in the system. At this time, the structure of the flexible chain of the TPU material can act as a stress concentrator, causing a large number of cracks, thereby absorbing a large amount of impact energy and improving the impact strength of the material;

[0041] 2. Multi-walled carbon nanotubes. As nanomaterials, carbon nanotubes have common characteristics such as a diameter less than 100nm, a large specific surface area, and obvious interface effects. At the same time, carbon nanotubes also have higher axial strength, higher mechanical strength, better biocompatibility, good thermal conductivity, electrical conductivity, high temperature resistance and other physical properties.

[0042] The addition of multi-walled carbon nanotubes can change the microphase separation structure of polyurethane, effectively preventing the migration of small molecules during aging in harsh environments, and has a certain effect on enhancing the mechanical properties and anti-aging properties of TPU in harsh high and low temperature corrosion environments;

[0043] The soft segments of polyether thermoplastic polyurethanes (TPUs) possess excellent flexibility due to their easily rotatable ether groups. Therefore, PPUs facilitate the dissolution and diffusion of blowing agent molecules. Carbon dioxide is a preferred blowing agent for the production of TPU foam beads because it is pollution-free and residue-free, and the resulting beads have a high expansion ratio and excellent performance. Polyurethane foams offer advantages such as low density, high specific strength, and good compatibility with other materials.

[0044] 3. The composite structure of the second TPU layer ultimately exhibits multiple independent bubble structures, giving the TPU film excellent impact resistance, light weight, and explosion resistance. Leveraging the impact resistance and mechanical property enhancements of MABS and multi-walled carbon nanotubes, and complemented by other additives, this layer of film exhibits excellent properties such as light weight, environmental protection, wear resistance, flame retardancy, explosion resistance, impact resistance, aging resistance, high and low temperature resistance, and corrosion resistance.

[0045] It should be added that the second TPU layer contains 15-20% by mass of toughening agent, 20% by mass of flame retardant, 2-4% by mass of UV absorber, 10-15% by mass of accelerator, 1-3% by mass of multi-walled carbon nanotube, 1-3% by mass of conductive agent, and the rest is polyether TPU.

[0046] In a preferred embodiment of the present invention, the fiber reinforcement layer is polyethylene and filler, because it has the characteristics of super wear resistance, self-lubrication, relatively high strength, stable chemical properties, and strong anti-aging performance.

[0047] It should be added that: the polyethylene is ultra-high molecular weight polyethylene, and at least one of glass beads, glass fibers, mica, talc, silica, aluminum oxide, molybdenum disulfide, carbon black, etc. can be selected to fill the ultra-high molecular weight polyethylene. By adding the above materials, the shortcomings of ultra-high molecular weight polyethylene such as low surface hardness and heat deformation temperature, poor bending strength and creep performance can be improved. This is caused by the molecular structure and molecular aggregation morphology of ultra-high molecular weight polyethylene, which has a certain impact on the softness, stackability and impact resistance of airdrop water bags. By selecting at least one of glass beads, glass fibers, mica, talc, silica, aluminum oxide, molybdenum disulfide, carbon black, etc., the shortcomings of ultra-high molecular weight polyethylene can be improved.

[0048] In a preferred embodiment of the present invention, the second adhesive layer is silicone adhesive.

[0049] In a preferred embodiment of the present invention, the first adhesive layer is formed by blending silicone adhesive, toughening agent, accelerator and auxiliary agents such as multi-walled carbon nanotubes.

[0050] This embodiment also discloses an airdrop TPU water bag composite material, the preparation method of which includes the following steps:

[0051] S1. Preparation of the first TPU layer:

[0052] The food-grade antimicrobial agent was placed in an oven at 80°C and dried for 24 hours. It was then added to the food-grade polyether TPU. After mixing, the mixture was melt-blended, extruded and cast into a film using a micro twin-screw extruder to form the first TPU layer.

[0053] During the S1 preparation process, the extrusion temperatures of the three sections in the micro twin-screw were 170°C, 175°C, and 180°C. In the first TPU layer, the mass fraction of the food-grade antimicrobial agent was 0.5-1%, and the rest was polyether TPU.

[0054] S2. Preparation of the second TPU layer:

[0055] (2) Weighing polyether TPU, toughening agent, flame retardant, ultraviolet absorber, accelerator, multi-walled carbon nanotubes and conductive agent according to mass ratio, and mixing them uniformly in an autoclave to obtain a matured and stable TPU foamed bead product;

[0056] In the S2, after being evenly mixed in the high-pressure reactor, the cooled and compressed CO2 is continuously and stably introduced in a constant pressure mode. That is, the solubility of supercritical carbon dioxide in the TPU mixture can be greatly reduced by rapidly reducing the pressure, so that the system is in an oversaturated state, thereby forcing the supercritical carbon dioxide to continuously overflow and produce tiny holes. These tiny holes act as nucleation points, and continue to relax as the internal pressure and the ambient pressure are balanced, and finally reach a stable state, and then obtain a matured and stable TPU foamed bead product.

[0057] The TPU foamed beads are melt-extruded and cast through a micro twin-screw extruder to finally form a second TPU layer.

[0058] S3, bonding and sealing the fiber reinforcement layer, the first TPU layer, and the second TPU layer using silicone adhesive;

[0059] The fiber reinforcement layer and the first TPU layer are bonded and sealed by using a mixture of silicone glue, toughening agent, accelerator and multi-walled carbon nanotubes.

[0060] It should be added that the fiber reinforcement layer can be made of ultra-high molecular weight polyethylene filled with at least one of glass beads, glass fibers, mica, talc, silicon dioxide, aluminum oxide, molybdenum disulfide, carbon black, etc.

[0061] It should be added that the adhesive used for bonding and sealing the fiber reinforcement layer and the second TPU layer is pure silicone adhesive.

[0062] It should be added that: in the first adhesive layer, the mass fraction of the toughening agent is 15-20%, the accelerator is 10-15%, the multi-walled carbon nanotubes is 1-3%, and the rest is silicone adhesive.

[0063] Now, the following four test cases were tested with different mass proportions of the components in the first TPU layer, the first adhesive layer, the fiber reinforcement layer, the second adhesive layer, and the second TPU layer, as shown in the following table:

[0064]

[0065]

[0066] In the table:

[0067] iHeir-ECO: food-grade antimicrobial agent; 58144: food-grade polyether TPU

[0068] MABS: toughening agent; DZ: rubber vulcanization accelerator; MWNT-COOH: multi-walled carbon nanotube;

[0069] Doher6000-5: Doher Chemical; Doher6000-5: flame retardant; VGCF: conductive agent; ZHF 80AT3: Lubrizol polyether TPU.

[0070] According to the above four test cases, the experimental results are as follows:

[0071]

[0072]

[0073] The table above shows that the addition of fillers to the fiber reinforcement layer has a certain impact on bending and folding, while also slightly affecting the bond strength. Toughening agents have a significant impact on impact resistance and puncture resistance, significantly reducing these resistances. Bond strength is also significantly low. Low CO2 bubbling agents significantly affect the puncture and impact resistance of the product, affecting its usability.

[0074] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An airdrop TPU water bag composite material, characterized in that: The adhesive layer comprises a first TPU layer, a first adhesive layer, a fiber reinforcement layer, a second adhesive layer and a second TPU layer, which are arranged in sequence from the inside out. The fiber reinforcement layer is composed of ultra-high molecular weight polyethylene and glass microspheres, with the mass fraction of ultra-high molecular weight polyethylene being 90% and the rest being glass microspheres; The second adhesive layer is silicone adhesive, and the mass fraction of the silicone adhesive is 100%; The first adhesive layer is formed by mixing silicone adhesive, a toughening agent, an accelerator and multi-walled carbon nanotubes, wherein the mass fraction of the toughening agent is 15%, the mass fraction of the accelerator is 10%, the mass fraction of the multi-walled carbon nanotubes is 3%, and the rest is silicone adhesive; The first TPU layer is made of a mixture of food-grade polyether TPU and a food-grade antibacterial agent, wherein the mass fraction of the food-grade antibacterial agent is 0.6%, and the rest is food-grade polyether TPU; In the second TPU layer, the mass fraction of the toughening agent is 15%, the mass fraction of the flame retardant is 20%, the mass fraction of the ultraviolet absorber is 2%, the mass fraction of the accelerator is 10%, the mass fraction of the multi-walled carbon nanotubes is 3%, the mass fraction of the conductive agent is 3%, and the rest is polyether TPU; The toughening agent is MABS; The preparation of the second TPU layer is step S2: Weighing polyether TPU, toughening agent, flame retardant, UV absorber, accelerator, multi-walled carbon nanotubes and conductive agent according to mass ratio, mixing them evenly in an autoclave, and then continuously and stably introducing cooled compressed CO2 in a constant pressure mode to obtain a matured and stable TPU foam bead product; The TPU foamed beads are melt-extruded and cast through a micro twin-screw extruder to finally form a second TPU layer.

2. The method for preparing an airdrop TPU water bag composite material according to claim 1, characterized in that: The following steps are involved: S1. Preparation of the first TPU layer: The food-grade antimicrobial agent was dried in an 80°C oven for 24 hours and then added to the food-grade polyether TPU. After mixing, the mixture was melt-blended, extruded and cast into a film using a micro twin-screw extruder. The three extrusion temperatures in the micro twin-screw extruder were set at 170°C, 175°C and 180°C respectively. S3, bonding and sealing the fiber reinforcement layer and the second TPU layer using a second adhesive layer; The fiber reinforcement layer and the first TPU layer are bonded and sealed using a first adhesive layer.

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