An environmentally friendly high-barrier composite hose made of a single material and its preparation method

Abstract

This invention discloses an environmentally friendly, single-material high-barrier composite hose and its preparation method, belonging to the field of composite hose technology. The environmentally friendly, single-material high-barrier composite hose provided by this invention is formed by butt-jointing or overlapping high-barrier composite sheets and then injection molding to add a 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 aluminized material layer or a silicon-plated material layer, and the aluminized or silicon-plated layer is further coated with a polyurethane coating or a polylactic acid coating. This invention reduces the risk of decreased barrier performance due to coating transfer and uneven coating by coating the intermediate aluminized or silicon-plated material layer with a polyurethane or polylactic acid coating. Furthermore, the use of a PE / EVOH / PE co-extruded film as a high-barrier inner layer in the heat-sealed inner layer significantly improves the barrier performance.

Description

Technical Field

[0001] This invention relates to the field of composite hose technology, specifically to an environmentally friendly high-barrier composite hose made of a single material and its preparation method. Background Technology

[0002] Composite hoses emerged in the 1990s to replace the original aluminum tubes. Due to their cost advantage, they have developed very rapidly in daily chemical packaging. Aluminum-plastic composite hoses generally use aluminum foil as a barrier layer, which has excellent light-blocking, oxygen-blocking and water-blocking properties. However, aluminum foil is expensive and has poor tear resistance. It is easily punctured or torn during production and processing, which further increases production costs. Compared with aluminum foil, aluminized film has a greater cost advantage and the following advantages: (1) Aluminized film has good physical and mechanical properties. It is not easy to be bent, wrinkled or broken during composite processing, which is conducive to improving production efficiency and qualified product rate; (2) Aluminized film is conductive. During processing, it can avoid quality problems or failures caused by static electricity, which is convenient for safe production. Especially when packaging powdery items, aluminized film can eliminate static electricity and ensure good sealing performance. (3) The main energy consumed by aluminized products is electricity. No wastewater or waste gas is generated during the production process, and the residual alumina can be recycled and reused. (4) The amount of aluminum deposited on the surface of the aluminized film during aluminization is very small (generally only 350~400 angstroms). Therefore, it can be considered that the essence of the substrate has not been changed. From an environmental protection perspective, the film that has been aluminized is still a "single material". Therefore, they can be more easily classified for recycling or incineration. However, aluminized films are prone to the phenomenon of aluminization layer transfer, which can easily lead to a decrease in the barrier performance of composite sheets. Silicon coating is a transparent packaging material with extremely high barrier performance first developed by Japan in the 1980s. It uses physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes to form a silicon oxide (SiOx) coating on the surface of a plastic substrate. This material has a nano-scale dense structure, low oxygen permeability, and stable performance in high temperature and high humidity environments. It can withstand high temperature cooking treatment at 135℃. Its transparency is comparable to that of glass, and it also has excellent gas barrier properties, making it an environmentally friendly alternative to aluminum foil and PVDC materials. However, the uniformity of the coating is difficult to control, which can also easily lead to a decrease in the barrier performance of the composite sheet. Summary of the Invention

[0003] To overcome the shortcomings of the existing technology, the present invention provides an environmentally friendly high-barrier composite hose made of a single material and its preparation method. By coating a polyurethane coating or polylactic acid coating on the intermediate aluminum or silicon material layer, the risk of decreased barrier performance due to coating transfer and uneven coating is reduced. Furthermore, a PE / EVOH / PE co-extruded film is used as a high-barrier inner layer in the heat-sealed inner layer, which greatly improves the barrier performance.

[0004] The technical solution for achieving the objective of this invention is as follows:

[0005] An environmentally friendly, single-material high-barrier composite hose is disclosed. The composite hose is formed by butt-jointing or overlapping high-barrier composite sheets and then injection molding the upper 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 aluminum-plated or silicon-plated layer is further coated with a polyurethane coating or a polylactic acid coating. The high-barrier inner layer is a PE / EVOH / PE co-extruded film.

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

[0007] In one particular embodiment, the intermediate layer is an aluminum-plated material layer, and the intermediate layer is further coated with a polyurethane coating or a polylactic acid coating.

[0008] In one particular embodiment, the intermediate layer is an aluminum-plated material layer, and the intermediate layer is further coated with a polyurethane coating.

[0009] In one particular embodiment, the intermediate layer is a silicon-plated material layer, and the intermediate layer is further coated with a polyurethane coating.

[0010] In one particular embodiment, the polyurethane coating may be derived from commercially available products or be homemade.

[0011] In a specific embodiment, the raw materials of the polyurethane coating, by molar ratio, comprise the following components: 40 parts polyether polyol, 5-20 parts silicone-protected catechol diol, 5-20 parts chain extender, 20-80 parts diisocyanate, 0.01-0.5 parts catalyst, 0-0.5 parts additives, 20-30 parts acetone, and 50-100 parts deionized water; the silicone-protected catechol diol has the structure shown in Formula 1:

[0012] Formula 1, where n is a natural number from 5 to 15, and R is methyl or tert-butyl.

[0013] 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 polypropylene glycol, polyethylene glycol, and polytetrahydrofuran glycol; the chain extender is a hydrophilic chain extender and a small molecule chain extender, wherein the hydrophilic chain extender is selected from at least one of dimethylolpropionic acid, dimethylolbutyric 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, wherein the organotin catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin dioctanoate, and stannous octanoate; the additives include 0.5-2 parts of a neutralizing agent and 0.05-0.2 parts of a defoamer, wherein the neutralizing agent is triethylamine, and the defoamer is an organosilicon defoamer.

[0014] In one specific embodiment, the method for preparing the silyl ether-protected catechol diol is as follows:

[0015] S1. Under anhydrous conditions, dopamine reacts with trimethylchlorosilane or tert-butyldimethylchlorosilane to generate hydroxyl-protected dopamine;

[0016] S2. Under anhydrous and oxygen-free conditions, hydroxyl-protected dopamine is reacted with methacryloyl chloride at 0-25°C for 2-4 hours under acid-binding agent and aprotic solvent conditions to obtain hydroxyl-protected dopamine monomer;

[0017] S3. Under anhydrous and oxygen-free conditions, terephthalic acid 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 under the action of a catalyst and ligand. The reaction temperature was 60~90℃ and the reaction time was 12~24 hours to obtain a silyl ether-protected catechol polymer.

[0018] S4. The silyl ether protected catechol polymer is reacted with water under alkaline conditions to obtain a silyl ether protected catechol polymer with hydroxyl groups at the end, which is simply referred to as silyl ether protected catechol diol.

[0019] In a specific embodiment, in step S1, the amount of trimethylchlorosilane or tert-butyldimethylchlorosilane 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 hydroxyl-protected dopamine monomer to initiator is (5 to 15):1, the catalyst is cuprous bromide, the ligand is pentamethyldiethylenetriamine, and the molar ratio of catalyst to ligand is 1:1.

[0020] In one specific embodiment, the method for preparing the polyurethane coating includes the following steps:

[0021] In a dry reaction vessel, add polyether diol and silicone ether-protected catechol diol, and dehydrate under vacuum at 80-100°C for 1-2 hours. Cool to 60-80°C, add diisocyanate and catalyst, and stir for 2-4 hours to obtain the prepolymer. Cool to 40-50°C, add acetone and a hydrophilic chain extender, and react for 1-2 hours. Cool to 30-40°C, add a small molecule chain extender, and continue reacting for 1-2 hours. Cool to room temperature, add tetrabutylammonium fluoride / tetrahydrofuran solution, and stir. After reacting for 2-4 hours, saturated ammonium chloride solution is added to quench excess tetrabutylammonium fluoride. The mixture is stirred for 10-30 minutes, and the organic phase is separated to obtain a polyurethane solution. Triethylamine is added dropwise to the polyurethane solution as a neutralizing agent, and the mixture is stirred at room temperature for 10-30 minutes. Then, under high-speed stirring, deionized water is slowly added, and the mixture is stirred for 20-60 minutes to form an emulsion. The emulsion is transferred to a rotary evaporator, and acetone and residual tetrahydrofuran are removed by vacuum distillation at 45-65°C to obtain an aqueous polyurethane with a solid content of 30-50 wt%.

[0022] In one specific embodiment, the outer PE layer is a highly transparent PE film with a thickness of 50-80 μm; the inner high-barrier layer has a thickness of 250-300 μm, wherein the EVOH layer has a thickness of 7-30 μm.

[0023] In one specific embodiment, the first adhesive layer is a polyurethane adhesive layer or a terpolymer resin layer; the second adhesive layer is a polyurethane adhesive layer or a polyethylene resin layer, and the thickness of the first adhesive layer and the second adhesive layer is 20~50μm.

[0024] In one specific embodiment, the aluminum-plated material layer is an aluminum-plated PE film with a thickness of 20-60 nm and the PE layer has a thickness of 25-60 μm; the silicon-plated material layer is a silicon-plated PLA film with a thickness of 20-60 μm.

[0025] This invention also protects a method for preparing an environmentally friendly, single-material, high-barrier composite flexible hose, comprising the following steps:

[0026] S1. Apply a polyurethane coating or polylactic acid coating to the coating side of the intermediate layer. After drying and curing, bond the PE outer layer, the first adhesive layer and the intermediate layer together through a dry lamination process or an extrusion lamination process; wherein the coating faces the outer layer.

[0027] 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 composite process or an extrusion composite process to obtain a high-barrier composite sheet.

[0028] S3. Weld the edges of the high-barrier composite sheet by overlapping or butt welding;

[0029] S4. Inject the upper shoulder of the hose with a molding temperature of 200-260℃, a pressure of 20-50 bar, and a cooling temperature of 10-20℃.

[0030] In one specific embodiment, the welding method involves adding a transparent welding strip to the weld seam and welding them together using a high-frequency induction coil. The high-frequency energy is 30%-100%, the cooling temperature is 15-22℃, and the pressure is 2-5kg.

[0031] In one specific embodiment, the overlap size is 2~2.5mm; the induction heating temperature is 85~95℃; and the weld compression ratio after pressure is 5~20%.

[0032] Beneficial effects

[0033] This invention provides an environmentally friendly, single-material, high-barrier composite hose and its preparation method, which has the following beneficial effects: A polyurethane coating or polylactic acid coating is applied to the aluminum-plated or silicon-plated material layer, reducing the risk of decreased barrier performance due to coating transfer and uneven coating. When the polyurethane coating is a self-made polyurethane coating, the addition of a diol with catechol segments, which has strong adhesive properties, allows the coating to adhere more tightly to the aluminum-plated and silicon-plated film surfaces compared to conventional polyurethane coatings, overcoming the poor adhesion between traditional polyurethane coatings and silicon-plated films. Furthermore, the catechol groups themselves possess certain chemical stability and low permeability, and waterborne polyurethane itself has good film-forming properties. The introduced catechol segments further optimize the film structure, 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. This further enhances its barrier effect. When the aluminized PE film or silicon-coated PE film is subjected to external forces during use, this strong adhesion effectively prevents the aluminum layer from detaching or transferring from the substrate. Simultaneously, it provides secondary protection for uneven silicon film coatings, significantly reducing the risk of decreased barrier performance due to aluminum film transfer or silicon film unevenness. To achieve a high barrier effect, this invention also uses a high-barrier PE / EVOH / PE co-extruded film instead of the traditional PE film material as the high-barrier inner layer, further improving the barrier performance of the composite flexible hose. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the layered structure of a high-barrier composite sheet, where 1 is the outer PE 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.

[0035] Figure 2 A schematic diagram of the synthetic route for protecting catechol diol with silyl ether;

[0036] Figure 3 The 1H NMR spectrum of the dopamine monomer protected by the hydroxyl group.

[0037] Figure 4 The 1H NMR spectrum of catechol diol protected by silyl ether. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0040] The raw materials used in the examples and comparative examples are described below:

[0041] Aluminized material layer: Aluminized PE film, aluminum layer thickness 60nm, PE thickness 30μm, Hangzhou Hongcheng Technology Co., Ltd.;

[0042] Silicone coating layer: Silicone PLA film, 20μm thick, Ceramis-CPM-003, Alcan Packaging, Switzerland;

[0043] Polyurethane coating 1: Waterborne polyurethane resin, HYDRAN HW-171, DIC (Diosmosis Technology);

[0044] First adhesive layer: polyurethane adhesive layer, SUPERGRIP 90LE, Bostik adhesive;

[0045] Second adhesive layer: Ethylene-methacrylic acid copolymer, Surlyn EMAA 7940, DuPont;

[0046] PE outer layer: High-transparency PE, 60μm thick, Guangzhou Yongxin Packaging;

[0047] High-barrier inner layer: PE / PE / TIE / EVOH / TIE / PE / PE multilayer co-extruded film, 280μm thick, of which EVOH is 20μm thick, Guangzhou Yongxin Packaging;

[0048] Silicone ether protected catechol diol: Preparation method is as follows:

[0049] S1. In a nitrogen atmosphere, 0.1 mol of dopamine and 100 ml of 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 homogenize the system. Under ice bath cooling at 0-5°C, 0.22 mol of anhydrous dichloromethane solution of tert-butyldimethylchlorosilane 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 completed, saturated ammonium chloride aqueous solution was added to the system to quench the reaction and stirred for 10 minutes. The mixture was separated, and the organic phase was washed twice with saturated brine, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation to obtain hydroxyl-protected dopamine.

[0050] S2. In a dry round-bottom flask, add 0.1 mol of hydroxyl-protected dopamine and 100 mL of anhydrous dichloromethane. Stir until homogeneous, 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, stirring for 5 minutes. Then, continue to slowly add 0.12 mol of methacryloyl chloride (dissolved in anhydrous dichloromethane), controlling the addition time to at least 15 minutes. After the addition is complete, maintain stirring in an ice bath for 30 minutes, then move to room temperature and react for 2 hours. After the reaction is complete, add 100 mL of saturated ammonium chloride aqueous solution to the system, stir for 10 minutes to terminate the reaction, separate the liquids, wash the organic phase twice with 100 mL of saturated brine, dry with anhydrous sodium sulfate, and filter. The solvent was removed by rotary evaporation under reduced pressure (35℃, 0.08 MPa) to obtain a pale yellow oily crude product. The product was purified by column chromatography (silica gel column, eluent: ethyl acetate / petroleum ether = 1:6). The target fraction was collected and evaporated to dryness to obtain a hydroxyl-protected dopamine monomer (yield 80%), 1H NMR (500 MHz, CDCl3) as shown. Figure 3 (As shown).

[0051] S3. Under a nitrogen atmosphere, add 0.1 mol of terephthalic acid 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 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, add 200 mL of saturated ammonium chloride to quench, separate the liquid and liquid phases, wash the organic phase with saturated brine until neutral, dry with anhydrous sodium sulfate, filter, remove the solvent by rotary evaporation, and purify by column chromatography (eluent: petroleum ether / ethyl acetate = 10:1) to obtain the initiator (yield 85%), and dry under vacuum for 24 hours for later use. The hydroxyl-protected dopamine monomer was subjected to 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-bisTBDMS-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. After sealing, the mixture was stirred for 10 minutes, heated to 70 °C in an oil bath, and stirred for 12 hours. The reaction was terminated by exposure to air. The mixture was diluted with 50 L of dichloromethane, filtered through a neutral alumina column to remove copper salts, and the solvent was removed by rotary evaporation. The crude product was dissolved in tetrahydrofuran, precipitated three times in n-hexane, and the solid was collected by centrifugation and vacuum dried for 24 hours to obtain a silyl ether-protected catechol polymer.

[0052] S4. In a round-bottom flask, add 0.5 g of polymer and 10 mL of methanol / water mixed solvent (volume ratio = 3:1). Stir and sonicate 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 terminal -Br of the polymer. After the reaction is complete, add a small amount of dilute hydrochloric acid (1 mol / L) to neutralize the excess potassium carbonate and adjust the pH to neutral. Extract the product with dichloromethane (20 mL × 3) and combine the organic phases. Dry the organic phase with anhydrous magnesium sulfate, filter, and evaporate the solvent under reduced pressure to obtain the crude product. Dissolve the crude product in a small amount of tetrahydrofuran, precipitate twice in n-hexane, collect the solid by centrifugation, and dry under vacuum for 24 hours to obtain silyl ether protected catechol diol. The molecular weight is 9300 as determined by GPC. 1H NMR (500 MHz, CDCl3) is as follows. Figure 4 As shown.

[0053] Polyether polyol: polyethylene glycol, molecular weight 2000, Shanghai Yuanye Biotechnology Co., Ltd.;

[0054] Diisocyanate: Isophorone diisocyanate, commercially available;

[0055] Catalyst: Dibutyltin dilaurate, commercially available;

[0056] Hydrophilic chain extender: dimethylolpropionic acid, commercially available;

[0057] Small molecule chain extender: ethylenediamine, commercially available;

[0058] Organotin catalyst: Dibutyltin dilaurate, commercially available;

[0059] Neutralizing agent: Triethylamine, commercially available;

[0060] Polyurethane coating 2: Self-made, preparation method is as follows:

[0061] Add 40 parts of polyether diol and 8 parts of silicone ether-protected catechol diol to a dry four-necked flask. Dehydrate under vacuum at 100°C for 2 hours (vacuum degree -0.095 MPa) to remove moisture. Cool to 70°C, add 25 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate catalyst, and stir at 70°C for 3 hours under nitrogen protection. 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, the temperature was lowered to 30°C, and 1.2 parts of ethylenediamine dissolved in 5 parts of acetone were slowly added dropwise. The mixture was stirred at room temperature for 1 hour to carry out the chain extension reaction. 6 volumes of tetrabutylammonium fluoride / tetrahydrofuran solution (1 mol / L) were added to the system, and the mixture was stirred at room temperature for 2 hours. TLC monitoring (eluent: ethyl acetate / petroleum ether = 1:1) showed that the starting material spot (Rf≈0.6) disappeared, and a new spot (free phenolic hydroxyl group, Rf≈0.3) was formed, indicating complete deprotection. 10 parts of saturated ammonium chloride solution were added to quench the excess tetrabutylammonium fluoride, and the mixture was stirred for 1 minute. The organic phase was separated to obtain the polyurethane solution. Add 2.5 parts of triethylamine to the polyurethane solution and stir at room temperature for 30 minutes. Then, stir at high speed (1200 rpm) and slowly add 80 parts of deionized water. Stir for another 30 minutes to form a milky white emulsion with a bluish tint. Filter the emulsion, controlling the particle size to 100-300 nm. Transfer the emulsion to a rotary evaporator and distill under reduced pressure at 45°C and a vacuum of -0.09 MPa to remove acetone and residual tetrahydrofuran, yielding a waterborne polyurethane coating with a solid content of 40%.

[0062] Polyurethane coating 3: self-made, the difference from polyurethane coating 2 is that the amount of silicone ether protecting catechol diol is modified to 5 parts;

[0063] Polyurethane coating 4: self-made, the difference from polyurethane coating 2 is that the amount of silicone ether protecting catechol diol is modified to 20 parts;

[0064] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0065] Example 1

[0066] An environmentally friendly, high-barrier composite flexible tube made of a single material is prepared as follows:

[0067] S1. A polyurethane coating 1 with a thickness of 30μm is applied to the coating side of the aluminum-plated PE film in the intermediate layer. After drying and curing, the outer PE layer, the polyurethane adhesive layer and the intermediate layer are bonded together by an extrusion composite process; wherein the coating faces the outer layer.

[0068] 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;

[0069] S3. The edges of the high-barrier composite sheet are butt-welded together using a transparent welding strip on the weld seam. The sheets are then welded together using a high-frequency induction coil with a high-frequency energy of 30%-100% and a cooling temperature of 15-22℃. The pressure is 2-5 kg.

[0070] S4. Inject the upper shoulder of the hose with a molding temperature of 200-260℃, a pressure of 20-50 bar, and a cooling temperature of 10-20℃.

[0071] The processing temperature is 220-320℃; the unwinding tension is 15-25kg; the winding tension is 20-35kg; and the composite pressure is 4-6kg.

[0072] Example 2

[0073] Compared with Example 1, the difference is that the aluminum-plated PE film in the middle layer is replaced with a silicon-plated PLA film;

[0074] Example 3

[0075] Compared with Example 1, the difference is that polyurethane coating 1 is replaced with polyurethane coating 2, and the intermediate aluminum-plated PE film is replaced with a silicon-plated PLA film.

[0076] Example 4

[0077] Compared with Example 1, the difference is that polyurethane coating 1 is replaced with polyurethane coating 2;

[0078] Example 5

[0079] Compared with Example 1, the difference is that polyurethane coating 1 is replaced with polyurethane coating 3;

[0080] Example 6

[0081] Compared with Example 1, the difference is that polyurethane coating 1 is replaced with polyurethane coating 4;

[0082] Comparative Example 1

[0083] Compared with Example 1, the difference is that the high-barrier inner layer is replaced with a high-transparency PE of the same thickness;

[0084] Comparative Example 2

[0085] Compared with Example 1, the difference is that the aluminum layer surface of the intermediate aluminized PE film is not coated with polyurethane coating.

[0086] Comparative Example 3

[0087] Compared with Example 1, the difference is that the intermediate aluminum-plated PE film is replaced with a silicon-plated PLA film, and the surface of the silicon film of the intermediate silicon-plated PLA film is not coated with polyurethane coating.

[0088] The prepared intermediate layer and high-barrier composite sheet were subjected to the following performance tests, and the results are shown in Table 1:

[0089] (1) Twist resistance: Cut a 280×200mm sample and, referring to the standard GB / T 41347-2022 "Test method for twist resistance of flexible packaging materials", rub the sample 270 times with a long stroke of a rubbing instrument at a frequency of 45 times / min. Check the number of pinholes before and after rubbing. Each sample is tested 3 times and the average value is taken. When the number of pinholes after rubbing is 0, the gas permeability before and after rubbing is further tested. The gas permeability is tested according to the standard GB / T-1038.2-2022, and the oxygen permeability of the intermediate layer is tested using the isobaric method.

[0090] (2) Water vapor permeability: A 3-33MA moisture permeability meter was used to test the water vapor barrier performance of the composite sheet using the cup method according to GB / T 1037-1988 standard. The water permeability of the composite sheet under standard atmospheric pressure for 24 hours was tested. The specific test conditions were set as follows: test temperature: room temperature: 25℃, test pressure: 1 atm, ambient humidity: 90%RH, gas atmosphere: water vapor, test time: 24 hours;

[0091] (3) Oxygen permeability: According to GB / T-1038.2-2022 standard, the oxygen permeability of composite sheet was tested using the isobaric method. The test temperature was room temperature: 25℃, the test pressure was 0.1MPa, the ambient humidity was 50%RH, the gas atmosphere was oxygen, and the test time was 24 hours.

[0092] Table 1 Performance test results of intermediate layer and composite sheet

[0093]

[0094] Based on the data from the embodiments and comparative examples, the high-barrier composite hose provided by the present invention has the advantages of good oxygen barrier performance and water vapor barrier performance. Furthermore, the self-made polyurethane coating has better adhesion than commercially available polyurethane compared to aluminum-plated or silicon-plated films, and the aluminum-plated layer is not easy to migrate or fall off, further ensuring the activity and safety of the contents.

[0095] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly, single-material, high-barrier composite flexible hose, characterized in that, The composite hose is made by butt-jointing or overlapping high-barrier composite sheets and then injection molding the upper 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 a polyurethane coating is also applied to the aluminum-plated material layer or the silicon-plated material layer. The high-barrier inner layer is a PE / EVOH / PE co-extruded film. The raw materials of the polyurethane coating, by weight, include the following components: 40 parts of polyether polyol, 5-20 parts of silicone ether-protected catechol diol, 5-20 parts of chain extender, 20-80 parts of diisocyanate, 0.01-0.5 parts of catalyst, 0-0.5 parts of additives, 20-30 parts of acetone, and 50-100 parts of deionized water. The silicone ether-protected catechol diol has the structure shown in Formula 1. Formula 1, where n is a natural number from 5 to 15, and R is methyl or tert-butyl.

2. The environmentally friendly single-material high-barrier composite flexible hose as described in claim 1, 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 polytetrahydrofuran glycol; the chain extender is a hydrophilic chain extender and a small molecule chain extender, wherein the hydrophilic chain extender is selected from at least one of dimethylolpropionic acid, dimethylolbutyric 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, wherein the organotin catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin dioctanoate, and stannous octanoate; the additives include 0.5-2 parts of a neutralizing agent and 0.05-0.2 parts of a defoamer, wherein the neutralizing agent is triethylamine, and the defoamer is an organosilicon defoamer.

3. The environmentally friendly single-material high-barrier composite flexible hose as described in claim 1, characterized in that, The method for preparing the silyl ether-protected catechol diol is as follows: S1. Under anhydrous conditions, dopamine reacts with trimethylchlorosilane or tert-butyldimethylchlorosilane to generate hydroxyl-protected dopamine; S2. Under anhydrous and oxygen-free conditions, hydroxyl-protected dopamine is reacted with methacryloyl chloride at 0-25°C for 2-4 hours under acid-binding agent and aprotic solvent conditions to obtain hydroxyl-protected dopamine monomer; S3. Under anhydrous and oxygen-free conditions, terephthalic acid 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 under the action of a catalyst and ligand. The reaction temperature was 60~90℃ and the reaction time was 12~24 hours to obtain a silyl ether-protected catechol polymer. S4. The silyl ether protected catechol polymer is reacted with water under alkaline conditions to obtain a silyl ether protected catechol polymer with hydroxyl groups at the end, which is simply referred to as silyl ether protected catechol diol.

4. The environmentally friendly single-material high-barrier composite flexible hose as described in claim 3, characterized in that, In step S1, the amount of trimethylchlorosilane or tert-butyldimethylchlorosilane 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 hydroxyl-protected dopamine monomer to initiator is (5 to 15):1, the catalyst is cuprous bromide, the ligand is pentamethyldiethylenetriamine, and the molar ratio of catalyst to ligand is 1:

1.

5. The environmentally friendly single-material high-barrier composite flexible hose as described in claim 1, characterized in that, The method for preparing the polyurethane coating includes the following steps: In a dry reaction vessel, add polyether diol and silicone ether-protected catechol diol, and dehydrate under vacuum at 80-100°C for 1-2 hours. Cool to 60-80°C, add diisocyanate and catalyst, and stir for 2-4 hours to obtain the prepolymer. Cool to 40-50°C, add acetone and a hydrophilic chain extender, and react for 1-2 hours. Cool to 30-40°C, add a small molecule chain extender, and continue reacting for 1-2 hours. Cool to room temperature, add tetrabutylammonium fluoride / tetrahydrofuran solution, and stir. After reacting for 2-4 hours, saturated ammonium chloride solution is added to quench excess tetrabutylammonium fluoride. The mixture is stirred for 10-30 minutes, and the organic phase is separated to obtain a polyurethane solution. Triethylamine is added dropwise to the polyurethane solution as a neutralizing agent, and the mixture is stirred at room temperature for 10-30 minutes. Then, under high-speed stirring, deionized water is slowly added, and the mixture is stirred for 20-60 minutes to form an emulsion. The emulsion is transferred to a rotary evaporator, and acetone and residual tetrahydrofuran are removed by vacuum distillation at 45-65°C to obtain an aqueous polyurethane with a solid content of 30-50 wt%.

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

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

8. The environmentally friendly single-material high-barrier composite flexible hose as described in claim 1, characterized in that, The aluminum-plated material layer is an aluminum-plated PE film with an aluminum layer thickness of 60-90 nm and a PE layer thickness of 25-60 μm; the silicon-plated material layer is a silicon-plated PLA film with a thickness of 20-60 μm.

9. The method for preparing the environmentally friendly single-material high-barrier composite flexible hose according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Apply a polyurethane coating to the plating side of the intermediate layer, and after drying and curing, bond the PE outer layer, the first adhesive layer and the intermediate layer together by a dry lamination process or an extrusion lamination process; wherein the coating faces the outer layer; S2. The composite sheet, the second adhesive layer and the high-barrier inner film obtained in step S1 are bonded together by a dry composite process or an extrusion composite process to obtain a high-barrier composite sheet. S3. Weld the edges of the high-barrier composite sheet by overlapping or butt welding; S4. Inject the upper shoulder of the hose with a molding temperature of 200-260℃, a pressure of 20-50 bar, and a cooling temperature of 10-20℃.

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