Environment-friendly single-material high-barrier composite hose and preparation method thereof

Abstract

The invention discloses an environment-friendly single-material high-barrier composite hose and a preparation method thereof, and belongs to the technical field of composite hoses.The environment-friendly single-material high-barrier composite hose is prepared by butt joint or lap joint of high-barrier composite sheets and injection molding of an upper pipe shoulder; the high-barrier composite sheet sequentially comprises a PE outer layer, a first bonding layer, a middle layer, a second bonding layer and a high-barrier inner layer, the middle layer is an aluminum-plated material layer or a silicon-plated material layer, and the plating layer of the aluminum-plated material layer or the silicon-plated material layer is also coated with a polyurethane coating or a polylactic acid coating. According to the invention, the polyurethane coating or the polylactic acid coating is coated on the plating layer of the middle aluminum-plated material layer or the silicon-plated material layer so as to reduce the risk of barrier property reduction caused by plating layer transfer and plating layer non-uniformity, and the PE / EVOH / PE co-extruded film is adopted as the high-barrier inner layer in the heat-sealing inner layer, so that the barrier property is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite hoses, in particular to an environment-friendly single-material high-barrier composite hose and a preparation method thereof. BACKGROUND

[0002] Composite hoses appeared in the 1990s to replace the original aluminum pipes, and due to the cost advantage, they have developed very rapidly in daily chemical packaging. The aluminum-plastic composite hose generally uses aluminum foil as the barrier layer, which has excellent light resistance, oxygen resistance and water resistance, etc. However, the cost of aluminum foil is high, and the tear resistance is poor, which is easy to be punctured or torn in the production and processing process, further increasing the production cost. Compared with aluminum foil, the aluminized film has the following advantages: (1) the aluminized film has good physical and mechanical properties, and is not easy to appear phenomena such as folding, wrinkling and breaking in the composite processing, which is beneficial to improve the production efficiency and the qualified rate; (2) the aluminized film has conductivity, which can avoid quality problems or failures caused by static electricity in the processing process, and is convenient for safe production, especially when packaging powdery materials, the aluminized film can play a role in eliminating static electricity, and ensure the good performance of the sealing performance. (3) The main energy consumed by aluminized products is electricity, and no waste water and waste gas will be generated in the production process, and the residual aluminum oxide can be recycled; (4) The aluminum deposited on the surface of the aluminized film is very small (generally only 350~400 angstroms), so it can be considered that it does not change the nature of the base material, from the perspective of environmental protection, the aluminized film is still a "single material", so they can be more easily classified for recycling production or incineration. However, the aluminized film is prone to aluminized layer transfer, which can easily cause the barrier performance of the composite sheet to decrease. Silicon plating film is a transparent packaging material with extremely high barrier performance developed by Japan in the 1980s, which uses physical vapor deposition (PVD) or chemical vapor deposition (CVD) process to form a silicon oxide (SiOx) plating layer on the surface of the plastic substrate. The material has a nanoscale dense structure, low oxygen transmission rate, and stable performance in high temperature and high humidity environment, and can withstand 135℃ high temperature cooking treatment. Its transparency is equivalent to glass, and it also has excellent gas barrier property, which becomes an environmentally friendly alternative to aluminum foil and PVDC material, but the uniformity of the plating layer is difficult to control, and it is also easy to cause the barrier performance of the composite sheet to decrease. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the present application provides an environment-friendly single-material high-barrier composite hose and a preparation method thereof, which coats a polyurethane coating or a polylactic acid coating on the plating layer of the middle aluminized material layer or the middle silicon plating material layer to reduce the risk of barrier performance decrease caused by plating layer transfer and uneven plating layer, and uses PE / EVOH / PE co-extruded film as a high-barrier inner layer in the heat-sealing inner layer, which greatly improves the barrier performance.

[0004] The technical solutions for achieving the purpose of the present invention are as follows: An environmentally friendly single-material high-barrier composite hose, which is made by butting or overlapping high-barrier composite sheets and then injection-molding the tube shoulder. The high-barrier composite sheet sequentially includes a PE outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer and a high-barrier inner layer; the intermediate layer is an aluminum-plated material layer or a silicon-plated material layer, and the coating of the aluminum-plated material layer or the silicon-plated material layer is also coated with a polyurethane coating or a polylactic acid coating; the high-barrier inner layer is a PE / EVOH / PE co-extruded film.

[0005] In a specific embodiment, the intermediate layer is a silicon-plated material layer, and the intermediate layer is a silicon-plated material layer further coated with a polyurethane coating or a polylactic acid coating.

[0006] In a specific embodiment, the intermediate layer is an aluminum-plated material layer, and the intermediate layer is an aluminum-plated material layer further coated with a polyurethane coating or a polylactic acid coating.

[0007] In a specific embodiment, the intermediate layer is an aluminum-plated material layer, and the intermediate layer is an aluminum-plated material layer coated with a polyurethane coating.

[0008] In a specific embodiment, the intermediate layer is a silicon-plated material layer, and the intermediate layer is a silicon-plated material layer further coated with a polyurethane coating.

[0009] In a specific embodiment, the polyurethane coating can be from a commercial product or homemade.

[0010] In a specific embodiment, the raw materials of the polyurethane coating include the following components by molar parts: 40 parts of polyether polyol, 5-20 parts of silane-protected catechol-based diol, 5-20 parts of chain extender, 20-80 parts of diisocyanate, 0.01-0.5 parts of catalyst, 0-0.5 parts of auxiliary agent, 20-30 parts of acetone, and 50-100 parts of deionized water; the silane-protected catechol-based diol has a structure as shown in Formula 1: Formula 1, wherein n is a natural number of 5 to 15, and R is a methyl group or a tert-butyl group.

[0011] In a specific embodiment, the diisocyanate is selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate; the polyether polyol is selected from at least one of polyoxypropylene glycol, polyethylene glycol, and polytetramethylene glycol; the chain extender is a hydrophilic chain extender and a small molecule chain extender, the hydrophilic chain extender is selected from at least one of dimethylol propionic acid, dimethylol butyric acid, and sodium ethylenediamine ethanesulfonate, and the small molecule chain extender is selected from at least one of ethylenediamine, 1,4-butanediol, and diethylenetriamine; the catalyst is an organotin catalyst, and the organotin catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin dioctoate, and stannous octoate; the auxiliary agent includes 0.5 to 2 parts of a neutralizer and 0.05 to 0.2 parts of a defoamer, the neutralizer is triethylamine, and the defoamer is a silicone defoamer.

[0012] In a specific embodiment, the preparation method of the silyl ether protected catechol-based diol is: S1. Under anhydrous conditions, dopamine reacts with trimethylsilyl chloride or tert-butyldimethylsilyl chloride to produce hydroxyl-protected dopamine; S2. Under anhydrous and oxygen-free conditions, reacting hydroxyl-protected dopamine with methacryloyl chloride in an acid-binding agent and an aprotic solvent at 0-25° C. for 2-4 hours to obtain a hydroxyl-protected dopamine monomer; S3. Under anhydrous and oxygen-free conditions, p-phenylenediol and 2-bromoisobutyryl bromide were mixed and stirred to prepare an initiator, a hydroxyl-protected dopamine monomer was mixed with the initiator, and atom transfer radical polymerization was carried out in the presence of a catalyst and a ligand at a temperature of 60-90°C for a reaction time of 12-24 hours to obtain a silyl ether-protected catechol-based polymer; S4. reacting the silyl ether-protected catechol-based polymer with water under alkaline conditions to obtain a silyl ether-protected catechol-based polymer having a hydroxyl group at the end, referred to as silyl ether-protected catechol-based diol.

[0013] In a specific embodiment, in step S1, the amount of trimethylsilyl chloride or tert-butyldimethylsilyl chloride added is 2.1 to 2.5 times the molar amount of dopamine; in step S2, the amount of methacryloyl chloride added is 1.1 to 1.3 times the amount of hydroxyl-protected dopamine, the acid binding agent is triethylamine, and the polymerization inhibitor is hydroquinone; in step S3, the molar ratio of the hydroxyl-protected dopamine monomer to the initiator is (5 to 15):1, the catalyst is cuprous bromide, the ligand is pentamethyldiethylenetriamine, and the molar ratio of the catalyst to the ligand is 1:1.

[0014] In a specific embodiment, the method for preparing the polyurethane coating comprises the following steps: In a dry reaction vessel, add polyether diol and silyl ether protected catechol diol, vacuum dehydration at 80-100°C for 1-2 hours, cool to 60-80°C, add diisocyanate and catalyst, stir and react for 2-4 hours to obtain a prepolymer; cool to 40-50°C, add acetone and hydrophilic chain extender, react for 1-2 hours, cool to 30-40°C, add small molecule chain extender, continue to react for 1-2 hours, cool to room temperature, add tetrabutylammonium fluoride / tetrahydrofuran solution to the system, stir The reaction was carried out for 2 to 4 hours, and a saturated ammonium chloride solution was added to quench the excess tetrabutylammonium fluoride. The mixture was stirred for 10 to 30 minutes, and the organic phase was retained after separation to obtain a polyurethane solution. Triethylamine was dropwise added to the polyurethane solution as a neutralizing agent, and the mixture was stirred at room temperature for 10 to 30 minutes. Then, deionized water was slowly added under high-speed stirring, and the mixture was stirred for 20 to 60 minutes to form an emulsion. The emulsion was transferred to a rotary evaporator, and acetone and residual tetrahydrofuran were removed by reduced pressure distillation at 45 to 65° C. to obtain an aqueous polyurethane with a solid content of 30 to 50 wt%.

[0015] In a specific embodiment, the PE outer layer is a highly transparent PE film with a thickness of 50 to 80 μm; the high barrier inner layer has a thickness of 250 to 300 μm, wherein the EVOH has a thickness of 7 to 30 μm.

[0016] In a specific embodiment, the first adhesive layer is a polyurethane glue layer or a terpolymer resin layer; the second adhesive layer is a polyurethane glue layer or a polyethylene resin layer, and the thickness of the first adhesive layer and the second adhesive layer is 20-50 μm.

[0017] In a specific embodiment, the aluminum-plated material layer is an aluminum-plated PE film with a thickness of 20-60 nm and a PE layer of 25-60 μm; the silicon-plated material layer is a silicon-plated PLA film with a thickness of 20-60 μm.

[0018] The present invention also provides a method for preparing an environmentally friendly single-material high-barrier composite hose, comprising the following steps: S1. A polyurethane coating or a polylactic acid coating is applied to the coating side of the intermediate layer. After drying and curing, the PE outer layer, the first adhesive layer and the intermediate layer are bonded together by a dry lamination process or an extrusion lamination process; wherein the coating faces the outer layer; S2. The composite sheet obtained in step S1, the second adhesive layer and the EVOH / PE inner layer film are bonded together by a dry lamination process or an extrusion lamination process to obtain a high-barrier composite sheet; S3. The edges of the high barrier composite sheet are welded by overlapping or butting; S4. Injection mold the upper tube shoulder on the hose at an injection temperature of 200-260°C, a pressure of 20-50 bar, and a cooling temperature of 10-20°C.

[0019] In a specific embodiment, the butt joint is formed by adding a transparent welding strip on the weld seam and welding them together through a high-frequency induction coil, with a high-frequency energy of 30%-100%; a cooling temperature of 15-22°C; and a pressure of 2-5kg.

[0020] In a specific embodiment, the overlap size is 2-2.5 mm; the induction heating temperature is 85-95° C., and the weld compression ratio after pressurization is 5-20%.

[0021] Beneficial effects

[0022] The present invention provides an environmentally friendly single-material high-barrier composite hose and a preparation method thereof, which has the following beneficial effects: a polyurethane coating or a polylactic acid coating is applied on the coating of the aluminum-plated material layer or the silicon-plated material layer, reducing the risk of reduced barrier performance due to coating transfer and uneven coating. When the applied polyurethane coating is a homemade polyurethane coating, since a diol having a catechol chain segment is additionally introduced into the homemade polyurethane coating, and the catechol group has strong adhesion, the coating can adhere tightly to the surface of the aluminum-plated film and the silicon-plated film compared to conventional polyurethane coatings, overcoming the disadvantage of poor adhesion of traditional polyurethane coatings to the silicon-plated film. In addition, the catechol group itself has certain chemical stability and low permeability, and the water-based polyurethane itself has good film-forming properties. The introduced catechol chain segment can further optimize the structure of the film, making it more dense, thereby improving the overall barrier effect and forming an effective barrier layer to prevent the penetration of small molecules such as oxygen and water vapor. Thereby further improving its barrier effect. When aluminized or siliconized PE films are subjected to external forces during use, this strong adhesion effectively prevents the aluminum layer from falling off or transferring from the substrate. It also acts as a secondary barrier to uneven silicon coating, significantly reducing the risk of barrier performance degradation due to aluminum transfer or silicon film unevenness. To achieve high barrier properties, the present invention also uses a high-barrier PE / EVOH / PE co-extruded film instead of traditional PE film as the high-barrier inner layer, further enhancing the barrier performance of the composite hose. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the layered structure of a high-barrier composite sheet, where 1 is the PE outer layer, 2 is the first adhesive layer, 3 is the middle layer, 4 is the second adhesive layer, and 5 is the high-barrier inner layer; Figure 2 Schematic diagram of the synthetic route of silyl ether protected catechol-based diols; Figure 3 This is the H NMR spectrum of the hydroxyl-protected dopamine monomer.

[0024] Figure 4 This is the H NMR spectrum of silyl ether protected catechol-based diol. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0027] The raw materials used in the embodiments and comparative examples are now described as follows: Aluminum-plated material layer: aluminized PE film, aluminum layer thickness 60nm, PE thickness 30μm, Hangzhou Hongcheng Technology Co., Ltd. Silicon-coated material layer: Silicon-coated PLA film, thickness 20 μm, Ceramis-CPM-003, Alcan Packaging, Switzerland; Polyurethane coating 1: water-based polyurethane resin, HYDRAN HW-171, DIC; First bonding layer: polyurethane glue layer, SUPERGRIP 90LE, Bostik; Second tie layer: ethylene methacrylic acid copolymer, Surlyn EMAA 7940, DuPont; PE outer layer: Highly transparent PE, thickness 60μm, Guangzhou Yongxin packaging; High barrier inner layer: PE / PE / TIE / EVOH / TIE / PE / PE multi-layer co-extruded film, thickness 280μm, of which EVOH thickness is 20μm, Guangzhou Yongxin Packaging; Silyl ether protected catechol-based diol: The preparation method is as follows: S1. In a nitrogen atmosphere, 0.1 mol dopamine and 100 ml anhydrous dichloromethane were added to a dry round-bottom flask and stirred to dissolve. Imidazole was added to the solution and stirred for 10 minutes to make the system uniform. Under ice bath cooling at 0-5°C, 0.22 mol of anhydrous dichloromethane solution of tert-butyldimethylsilyl chloride was slowly added dropwise. After the addition was complete, the ice bath was removed and the reaction was stirred at room temperature for 5 hours. After the reaction was complete, a saturated aqueous ammonium chloride solution was added to the system to quench the reaction, stirred for 10 minutes, and the liquids were separated. The organic phase was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated under reduced pressure to obtain hydroxyl-protected dopamine; S2. In a dry round-bottom flask, add 0.1 mol of hydroxyl-protected dopamine and 100 ml of anhydrous dichloromethane. Stir thoroughly, then add 5 mmol of hydroquinone as a polymerization inhibitor. Cool in an ice bath to 0-5°C. Slowly add 0.2 mol of triethylamine dropwise. Stir for 5 minutes, then slowly add 0.12 mol of methacryloyl chloride (dissolved in anhydrous dichloromethane) dropwise over 15 minutes. After the addition is complete, stir in the ice bath for 30 minutes, then bring to room temperature and react for 2 hours. After the reaction is complete, add 100 mL of saturated ammonium chloride aqueous solution and stir for 10 minutes to terminate the reaction. Separate the mixture, wash the organic phase twice with 100 mL of saturated brine, dry over anhydrous sodium sulfate, and filter. The solvent was removed by rotary evaporation under reduced pressure (35°C, 0.08 MPa) to obtain a pale yellow oily crude product, which was purified by column chromatography (silica gel column, eluent: ethyl acetate / petroleum ether = 1:6). The target fractions were collected and dried to obtain the hydroxyl-protected dopamine monomer (yield 80%, nuclear magnetic resonance hydrogen spectrum 1H NMR (500 MHz, CDCl3) as shown in FIG. Figure 3 shown).

[0028] S3. Under a nitrogen atmosphere, add 0.1 mol of p-phenylenediol and 200 mL of anhydrous dichloromethane to a flask, stir to dissolve, cool in an ice bath to 0-5°C, slowly add triethylamine dropwise, and then add a solution of 0.22 mol of 2-bromoisobutyryl bromide in anhydrous dichloromethane dropwise through a dropping funnel. A white precipitate gradually forms in the system. After the addition is complete, remove the ice bath, stir at room temperature for 4-6 hours, quench with 200 mL of saturated ammonium chloride, separate the liquids, wash the organic phase with saturated brine until neutral, dry over anhydrous sodium sulfate, filter, and evaporate to remove the solvent. Purify by column chromatography (eluent: petroleum ether / ethyl acetate = 10:1) to obtain the initiator (yield 85%), and dry in vacuo for 24 hours. The hydroxyl-protected dopamine monomer was passed through an alkaline alumina column to remove the polymerization inhibitor. Under strictly anhydrous and oxygen-free conditions, 0.2 mol of initiator, 20 mol of N-methacryloyl-bis-TBDMS-protected dopamine, and 20 L of anhydrous toluene were stirred and dissolved. 0.24 mol of CuBr was added, and 0.24 mol of PMDETA ligand was rapidly injected. The mixture was sealed and stirred for 10 minutes. The oil bath was heated to 70°C and stirred for 12 hours. The reaction was terminated by exposure to air, and the mixture was diluted with 50 L of dichloromethane. The copper salt was filtered through a neutral alumina column, and the solvent was removed by rotary evaporation. The crude product was dissolved in tetrahydrofuran and precipitated in n-hexane three times. The solid was collected by centrifugation and vacuum dried for 24 hours to obtain a silyl ether-protected catechol-based polymer. S4. Add 0.5 g of polymer and 10 mL of a methanol / water mixed solvent (volume ratio = 3:1) to a round-bottom flask. Stir and ultrasonicate to disperse and dissolve the polymer. Add 1.0 g of potassium carbonate solid and stir at room temperature for 12 hours to hydroxylate the -Br group at the polymer end. After the reaction is complete, add a small amount of dilute hydrochloric acid (1 mol / L) to neutralize the excess potassium carbonate, adjust the pH to neutral, extract the product with dichloromethane (20 mL×3), and combine the organic phases. Dry the organic phase over anhydrous magnesium sulfate, filter, and evaporate the solvent under reduced pressure to obtain a crude product. Dissolve the crude product in a small amount of tetrahydrofuran and precipitate twice in n-hexane. Collect the solid by centrifugation and vacuum dry for 24 hours to obtain a silyl ether-protected catechol-based diol. The molecular weight determined by GPC is 9300, and the nuclear magnetic hydrogen spectrum 1H NMR (500 MHz, CDCl3) is as follows: Figure 4 shown.

[0029] Polyether polyol: polyethylene glycol, molecular weight 2000, Shanghai Yuanye Biotechnology Co., Ltd. Diisocyanate: isophorone diisocyanate, commercially available; Catalyst: dibutyltin dilaurate, commercially available; Hydrophilic chain extender: dimethylolpropionic acid, commercially available; Small molecule chain extender: ethylenediamine, commercially available; Organic tin catalyst: dibutyltin dilaurate, commercially available; Neutralizing agent: triethylamine, commercially available; Polyurethane coating 2: Homemade, preparation method is as follows: In a dry four-necked flask, add 40 parts of polyether diol and 8 parts of silane-protected catechol diol, dehydrate at 100°C for 2 hours (vacuum degree -0.095MPa) to remove moisture, cool to 70°C, add 25 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate catalyst, and react at 70°C under nitrogen protection with stirring for 3 hours; cool to 50°C, add 4 parts of dimethylolpropionic acid and 15 parts of acetone, and continue the reaction at 50°C for 1 hour. After 5 hours of cooling to 30°C, 1.2 parts of ethylenediamine dissolved in 5 parts of acetone was slowly added dropwise, and the reaction was stirred at room temperature for 1 hour to allow chain extension. Six parts by volume of a 1 mol / L tetrabutylammonium fluoride / tetrahydrofuran solution was added to the system, and the mixture was stirred at room temperature for 2 hours. TLC monitoring (developing solvent: ethyl acetate / petroleum ether = 1:1) revealed the disappearance of the starting material spot (Rf ≈ 0.6) and the formation of a new spot (free phenolic hydroxyl group, Rf ≈ 0.3), indicating complete deprotection. Excess tetrabutylammonium fluoride was quenched by the addition of 10 parts of saturated ammonium chloride solution, and the mixture was stirred for 1 minute. The organic phase was then separated to obtain a polyurethane solution. 2.5 parts of triethylamine were added to the polyurethane solution, and the mixture was stirred at room temperature for 30 minutes. Then, 80 parts of deionized water were slowly added under high-speed stirring at 1200 rpm and stirred for 30 minutes to form a milky white emulsion with a blue light. The solution was filtered and the particle size was controlled at 100-300 nm. The emulsion was transferred to a rotary evaporator and distilled under reduced pressure at 45°C and a vacuum degree of -0.09 MPa to remove acetone and residual tetrahydrofuran to obtain a water-based polyurethane coating with a solid content of 40%.

[0030] Polyurethane coating 3: homemade. Compared with polyurethane coating 2, the difference is that the amount of silane-protected catechol-based diol added is modified to 5 parts; Polyurethane coating 4: homemade. Compared with polyurethane coating 2, the difference is that the amount of silane-protected catechol-based diol added is modified to 20 parts. Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0031] Example 1

[0032] An environmentally friendly single-material high-barrier composite hose, the preparation method is as follows: S1. A polyurethane coating 1 is coated on the coating side of the intermediate layer of aluminum-coated PE film to a thickness of 30 μm. After drying and curing, the PE outer layer, the polyurethane glue layer and the intermediate layer are bonded together by an extrusion composite process; wherein the coating faces the outer layer; S2. The composite sheet obtained in step S1, the ethylene-methacrylic acid copolymer and the high-barrier inner layer are bonded together by an extrusion composite process to obtain a high-barrier composite sheet; S3. Butt-weld the edges of the high-barrier composite sheets. A transparent welding strip is added to the weld seam. The sheets are welded together using a high-frequency induction coil with a high-frequency energy of 30%-100%. The cooling temperature is 15-22°C, and the pressure is 2-5kg. S4. Injection mold the upper tube shoulder on the hose at an injection temperature of 200-260°C, a pressure of 20-50 bar, and a cooling temperature of 10-20°C.

[0033] Among them, the processing temperature is 220-320℃; the unwinding tension is 15-25kg; the winding tension is 20-35kg; the compounding pressure is 4-6kg; Example 2

[0034] Compared with Example 1, the difference is that the middle layer of aluminum-coated PE film is replaced by silicon-coated PLA film; Example 3

[0035] Compared with Example 1, the difference is that the polyurethane coating 1 is replaced by the polyurethane coating 2, and the middle layer of aluminum-plated PE film is replaced by silicon-plated PLA film; Example 4

[0036] Compared with Example 1, the difference is that the polyurethane coating 1 is replaced by the polyurethane coating 2; Example 5

[0037] Compared with Example 1, the difference is that the polyurethane coating 1 is replaced by the polyurethane coating 3; Example 6

[0038] Compared with Example 1, the difference is that the polyurethane coating 1 is replaced by the polyurethane coating 4; Comparative Example 1 Compared with Example 1, the difference is that the high barrier inner layer is replaced with high-transparency PE of the same thickness; Comparative Example 2 Compared with Example 1, the difference is that the aluminum layer surface of the middle layer aluminum-plated PE film is not coated with polyurethane coating; Comparative Example 3 Compared with Example 1, the difference is that the middle layer of aluminum-coated PE film is replaced by a silicon-coated PLA film, and the silicon film surface of the middle layer of silicon-coated PLA film is not coated with polyurethane coating; The prepared intermediate layer and high barrier composite sheet were subjected to the following performance tests, and the results are shown in Table 1: (1) Rub resistance: Cut a sample of 280×200 mm and refer to the standard GB / T 41347-2022 "Test method for rub resistance of flexible packaging materials". Use a rubbing instrument to rub the sample 270 times with a long stroke and a frequency of 45 times / min. Check the number of pinholes before and after rubbing. Repeat the test for each sample 3 times and take the average value. When the number of pinholes after rubbing is 0, further test the gas permeability before and after rubbing. The gas permeability is based on the GB / T-1038.2-2022 standard and the oxygen permeability of the middle layer is tested using the isobaric method principle.

[0039] (2) Water vapor transmission rate: The water vapor barrier performance of the composite sheet was tested using a 3-33MA moisture permeability tester in accordance with GB / T 1037-1988 using the cup method. The water permeability of the composite sheet was tested under standard atmospheric pressure for 24 hours. The specific test conditions were as follows: test temperature: room temperature: 25°C, test pressure: 1 atm, ambient humidity: 90% RH, gas atmosphere: water vapor, test time: 24 hours; (3) Oxygen permeability: According to GB / T-1038.2-2022 standard, the oxygen permeability of the composite sheet is tested using the isobaric method principle. The test temperature is room temperature: 25°C, the test pressure is 0.1 MPa, the ambient humidity is 50% RH, the gas atmosphere is oxygen, and the test time is 24 hours.

[0040] Table 1 Performance test results of intermediate layer and composite sheet

[0041] Judging from the data of the embodiments and comparative examples, the high-barrier composite hose provided by the present invention has the advantages of good oxygen barrier properties and water vapor barrier properties, and the homemade polyurethane coating has better firmness than the commercially available polyurethane with aluminum-plated film or silicon-plated film, and the aluminum-plated layer is not easy to migrate or fall off, further ensuring the activity and safety of the contents.

[0042] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly single-material high-barrier composite hose, characterized in that: The composite hose is made by butting or overlapping high-barrier composite sheets and then injection-molding the tube shoulders. The high-barrier composite sheet sequentially includes a PE outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer and a high-barrier inner layer; the intermediate layer is an aluminum-plated material layer or a silicon-plated material layer, and the aluminum-plated material layer or the silicon-plated material layer is also coated with a polyurethane coating or a polylactic acid coating. The high-barrier inner layer is a PE / EVOH / PE co-extruded film.

2. The environmentally friendly single-material high-barrier composite hose according to claim 1, characterized in that: The raw materials of the polyurethane coating include the following components by weight: 40 parts of polyether polyol, 5-20 parts of silane-protected catechol-based diol, 5-20 parts of chain extender, 20-80 parts of diisocyanate, 0.01-0.5 parts of catalyst, 0-0.5 parts of auxiliary agent, 20-30 parts of acetone, and 50-100 parts of deionized water; the silane-protected catechol-based diol has a structure as shown in Formula 1: Formula 1, wherein n is a natural number of 5 to 15, and R is a methyl group or a tert-butyl group.

3. The environmentally friendly single-material high-barrier composite hose according to claim 2, characterized in that: The diisocyanate is selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate; the polyether polyol is selected from at least one of polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; the chain extender is a hydrophilic chain extender and a small molecule chain extender, the hydrophilic chain extender is selected from at least one of dimethylol propionic acid, dimethylol butyric acid, and sodium ethylenediamine ethanesulfonate, and the small molecule chain extender is selected from at least one of ethylenediamine, 1,4-butanediol, and diethylenetriamine; the catalyst is an organotin catalyst, and the organotin catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin dioctoate, and stannous octoate; the auxiliary agent includes 0.5-2 parts of a neutralizer and 0.05-0.2 parts of a defoamer, the neutralizer is triethylamine, and the defoamer is an organosilicon defoamer.

4. The environmentally friendly single-material high-barrier composite hose according to claim 2, characterized in that: The preparation method of the silyl ether protected catechol-based diol is: S1. Under anhydrous conditions, dopamine reacts with trimethylsilyl chloride or tert-butyldimethylsilyl chloride to produce hydroxyl-protected dopamine; S2. Under anhydrous and oxygen-free conditions, reacting hydroxyl-protected dopamine with methacryloyl chloride in an acid-binding agent and an aprotic solvent at 0-25° C. for 2-4 hours to obtain a hydroxyl-protected dopamine monomer; S3. Under anhydrous and oxygen-free conditions, p-phenylenediol and 2-bromoisobutyryl bromide were mixed and stirred to prepare an initiator, a hydroxyl-protected dopamine monomer was mixed with the initiator, and atom transfer radical polymerization was carried out in the presence of a catalyst and a ligand at a temperature of 60-90°C for a reaction time of 12-24 hours to obtain a silyl ether-protected catechol-based polymer; S4. reacting the silyl ether-protected catechol-based polymer with water under alkaline conditions to obtain a silyl ether-protected catechol-based polymer having a hydroxyl group at the end, referred to as silyl ether-protected catechol-based diol.

5. The environmentally friendly single-material high-barrier composite hose according to claim 4, characterized in that: In step S1, the amount of trimethylsilyl chloride or tert-butyldimethylsilyl chloride added is 2.1 to 2.5 times the molar amount of dopamine; in step S2, the amount of methacryloyl chloride added is 1.1 to 1.3 times the amount of hydroxyl-protected dopamine, the acid binding agent is triethylamine, and the polymerization inhibitor is hydroquinone; in step S3, the molar ratio of the hydroxyl-protected dopamine monomer to the initiator is (5 to 15):1, the catalyst is cuprous bromide, the ligand is pentamethyldiethylenetriamine, and the molar ratio of the catalyst to the ligand is 1:

1.

6. The environmentally friendly single-material high-barrier composite hose according to claim 2, characterized in that: The preparation method of the polyurethane coating comprises the following steps: In a dry reaction vessel, add polyether diol and silyl ether protected catechol diol, vacuum dehydration at 80-100°C for 1-2 hours, cool to 60-80°C, add diisocyanate and catalyst, stir and react for 2-4 hours to obtain a prepolymer; cool to 40-50°C, add acetone and hydrophilic chain extender, react for 1-2 hours, cool to 30-40°C, add small molecule chain extender, continue to react for 1-2 hours, cool to room temperature, add tetrabutylammonium fluoride / tetrahydrofuran solution to the system, stir The reaction was carried out for 2 to 4 hours, and a saturated ammonium chloride solution was added to quench the excess tetrabutylammonium fluoride. The mixture was stirred for 10 to 30 minutes, and the organic phase was retained after separation to obtain a polyurethane solution. Triethylamine was dropwise added to the polyurethane solution as a neutralizing agent, and the mixture was stirred at room temperature for 10 to 30 minutes. Then, deionized water was slowly added under high-speed stirring, and the mixture was stirred for 20 to 60 minutes to form an emulsion. The emulsion was transferred to a rotary evaporator, and acetone and residual tetrahydrofuran were removed by reduced pressure distillation at 45 to 65° C. to obtain an aqueous polyurethane with a solid content of 30 to 50 wt%.

7. The environmentally friendly single-material high-barrier composite hose according to claim 1, characterized in that: The PE outer layer is a highly transparent PE film with a thickness of 50 to 80 μm; the high barrier inner layer has a thickness of 250 to 300 μm, wherein the thickness of the EVOH is 7 to 30 μm.

8. The environmentally friendly single-material high-barrier composite hose according to claim 1, characterized in that: The first adhesive layer is a polyurethane glue layer or a terpolymer resin layer; the second adhesive layer is a polyurethane glue layer or an ethylene-methacrylic acid copolymer layer, and the thickness of the first adhesive layer and the second adhesive layer is 20-50 μm.

9. The environmentally friendly single-material high-barrier composite hose according to claim 1, characterized in that: The aluminum-plated material layer is an aluminum-plated PE film, the aluminum layer thickness is 60-90 nm, and the PE layer is 25-60 μm; the silicon-plated material layer is a silicon-plated PLA film, and the thickness is 20-60 μm.

10. The method for preparing an environmentally friendly single-material high-barrier composite hose according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. A polyurethane coating or a polylactic acid coating is applied to the coating side of the intermediate layer. After drying and curing, the PE outer layer, the first adhesive layer and the intermediate layer are bonded together by a dry lamination process or an extrusion lamination process; wherein the coating faces the outer layer; S2. The composite sheet obtained in step S1, the second adhesive layer and the high barrier inner layer film are bonded together by a dry lamination process or an extrusion lamination process to obtain a high barrier composite sheet; S3. The edges of the high barrier composite sheet are welded by overlapping or butting; S4. Injection mold the upper tube shoulder on the hose at an injection temperature of 200-260°C, a pressure of 20-50 bar, and a cooling temperature of 10-20°C.

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