A one-piece molded all-plastic flexible hose sheet and its composite hose

Abstract

This invention discloses a one-piece molded all-plastic flexible hose sheet and its composite hose, belonging to the field of polymer material technology. The one-piece molded all-plastic flexible hose sheet of this invention has a three-layer structure: an outer PE film, an intermediate layer, and an inner PE film. The intermediate layer is selected from one of the following: an intermediate polymer layer, a three-layer composite layer formed by an intermediate polymer layer, a polyethylene layer, and an intermediate polymer layer, or a three-layer composite layer formed by an intermediate polymer layer, an ethylene-vinyl alcohol copolymer layer, and an intermediate polymer layer; the intermediate layer may have a double-sided coated or uncoated adhesive layer; the intermediate polymer layer is polymerized from 2,6-dihydroxyisophthalic acid, diaminoalkane, and 4,4'-tetraphenylsilane. The all-plastic flexible hose sheet provided by this invention is formed in one piece using a five-layer co-extrusion machine, possessing excellent gas barrier properties, water vapor barrier properties, high mechanical strength, and good interlayer peel strength.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a one-piece molded all-plastic flexible sheet and its composite flexible sheet. Background Technology

[0002] Flexible tubing, a type of container widely used in daily chemical, pharmaceutical, and food industries, is favored by the market due to its ease of use, good sealing, and portability. Traditional composite tubing often uses aluminum-plastic composite structures or nylon materials.

[0003] The aluminum foil layer provides excellent gas barrier properties (such as oxygen and water vapor) and light shielding, effectively protecting the contents from external environmental influences and extending the product's shelf life. However, this type of hose has significant drawbacks in post-use recycling: due to the heterogeneous aluminum-plastic composite material, it is difficult to separate effectively, resulting in complex and costly recycling processes, and the recycled materials are of poor quality, with most ultimately becoming waste, putting pressure on the environment.

[0004] Nylon hoses, due to their dense molecular structure, exhibit certain advantages in solvent resistance and fatigue resistance, making them potentially suitable for packaging some daily chemical products. However, several technical defects severely limit their large-scale application. First, their temperature resistance is insufficient. Ordinary nylon hoses are prone to softening and deformation in high-temperature environments (such as summer transport compartments and bathrooms where temperatures exceed 60°C), leading to sealing failure at the hose openings or adhesion between the hose walls. In low-temperature environments (such as outdoor storage in winter at temperatures below -10°C), they become brittle and easily crack under pressure, making them unsuitable for daily chemical products that need to be stored in extreme temperature zones (such as car sunscreen sprays and winter outdoor hand creams). Second, their cost and processing difficulty are higher. The raw material cost of nylon materials (such as nylon 66, which costs approximately 25,000 yuan / ton) is 1.8-2 times that of PE materials. Third, their resistance to strong alkalis / strong oxidizing agents is insufficient, easily leading to hose wall aging, embrittlement, and even the risk of trace component migration. Fourth, its environmental recyclability needs improvement. Pure nylon hoses are difficult to recycle, and the difficulty in disassembling the material reduces the recycling rate, failing to meet the requirements of EU environmental regulations such as the Packaging and Packaging Waste Directive (PPWR). Fifth, nylon materials are highly absorbent, making it difficult to meet the packaging requirements of products containing water.

[0005] Therefore, developing a new type of high-performance all-plastic composite hose that possesses high barrier properties and high mechanical strength comparable to traditional aluminum-plastic composite hoses or nylon-based all-plastic hoses, while overcoming the shortcomings of nylon materials such as high hygroscopicity and low-temperature brittleness, and achieving good interlayer adhesion without the need to introduce additional adhesive layers, thereby simplifying the structure, reducing costs, and truly achieving easy recycling, has become a key technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a one-piece molded all-plastic hose sheet and its composite hose, which has the technical effects of acid and alkali resistance, gas barrier and liquid barrier, and the middle layer has good mechanical strength and flexibility and is easy to bond with the inner and outer layers.

[0007] This invention is achieved through the following technical solution: providing a one-piece molded all-plastic flexible hose sheet, the sheet having a three-layer structure: an outer PE film, an intermediate layer, and an inner PE film. The intermediate layer is selected from one of the following: an intermediate polymer layer, a three-layer composite layer formed by an intermediate polymer layer, a polyethylene layer, and an intermediate polymer layer, or a three-layer composite layer formed by an intermediate polymer layer, an ethylene-vinyl alcohol copolymer layer, and an intermediate polymer layer; the intermediate layer may be coated with or uncoated with an adhesive layer on both sides.

[0008] The intermediate layer polymer is polymerized from monomer A: 2,6-dihydroxyisophthalic acid, monomer B: diaminoalkane, and monomer C: 4,4'-tetraphenylsilanedicarboxylic acid.

[0009] The method for preparing the intermediate layer polymer includes:

[0010] Step S1: Dissolve monomers A and C in an organic solvent, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), stir for 1-4 h to obtain a carboxyl-activated solution.

[0011] Step S2: Dissolve monomer B in an organic solvent and slowly add it to the carboxyl activation solution. Under nitrogen protection, stir the reaction for 2-5 hours, then separate, purify, and dry to obtain the final product.

[0012] The organic solvents used in steps S1 and S2 are selected from one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), or N,N-dimethylacetamide (DMAc).

[0013] The molar ratio of monomers A, B, and C is (30-40):(80-95):(50-55). The molar ratio of EDC and NHS is 1:(0.8-1.2).

[0014] The diaminoalkane is selected from one of 1,7-diaminoheptane, 1,5-diaminopentane, 1,6-diaminohexane, and 1,4-diaminobutane.

[0015] The adhesive layer is a polyethylene adhesive layer, and the polyethylene adhesive layer is selected from at least one of maleic anhydride-grafted polyethylene and acrylate-grafted polyethylene.

[0016] The outer PE material, the middle layer material, and the outer PE material are fed into the extruder corresponding to the five-layer co-extrusion machine. The film is formed by co-extrusion process, and the processing temperature is maintained at 150℃-190℃. Then, a corona treatment is performed using a corona machine to obtain a one-time molded all-plastic hose sheet.

[0017] The present invention also provides a composite hose comprising a tube body made of the aforementioned one-piece molded all-plastic hose sheet.

[0018] Compared with the prior art, the present invention has the following beneficial effects.

[0019] This invention provides a composite hose made from a one-piece molded all-plastic flexible sheet. The all-plastic flexible sheet has three layers: an outer PE film, a middle layer, and an inner PE film. It possesses acid and alkali resistance, gas barrier properties, and liquid barrier properties. Furthermore, the middle layer exhibits good mechanical strength and flexibility, and is easily bonded to the inner and outer layers.

[0020] The intermediate layer polymer is prepared from monomers A, B, and C. The polymer is rich in benzene ring structures, and the stacking effect of these benzene rings in the molecules enhances the material's barrier properties, effectively preventing the passage of gases and liquids (water vapor). Furthermore, monomer A is rich in hydroxyl groups, which can form hydrogen bonds between molecules, further strengthening the barrier effect of the material prepared from the intermediate layer polymer. Although the intermediate layer polymer is rich in polar groups such as hydroxyl and amide groups, its multi-benzene ring structure, due to the stacking and steric occlusion effects of the benzene rings, results in strong hydrophobicity and low water absorption.

[0021] Monomer B has a linear carbon chain, which gives the intermediate polymer a certain degree of flexibility.

[0022] The intermediate layer polymer enhances the smoothness and hydrophobicity of the intermediate layer interface due to the π-π stacking of benzene rings, which can improve the bonding force with the PE layer. It can be directly compounded without an adhesive layer and still maintain good interfacial bonding ability. Attached Figure Description

[0023] Figure 1 This is a flowchart of the synthesis process of the intermediate layer polymer.

[0024] Figure 2 This is the infrared spectrum of the intermediate polymer 1. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The described embodiments are only some preferred embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise specified, the experimental methods used in the embodiments are conventional or common methods in the art, and the materials and reagents used are commercially available unless otherwise specified.

[0027] The raw materials used in the examples and comparative examples are described below:

[0028] 2,6-Dihydroxyisophthalic acid: purchased from Zhengzhou Aikem Chemical Co., Ltd.;

[0029] 4,4'-Tetraphenylsilanedicarboxylic acid: purchased from Zhengzhou Huiju Chemical Co., Ltd.;

[0030] 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride EDC: purchased from Jier Biochemical (Shanghai) Co., Ltd.;

[0031] N-Hydroxysuccinimide (NHS): Purchased from Jier Biochemical (Shanghai) Co., Ltd.;

[0032] Ethylenediamine: purchased from Shanghai E. En Chemical Technology Co., Ltd.;

[0033] 1,7-Diaminoheptane: purchased from Shanghai E. En Chemical Technology Co., Ltd.;

[0034] 1,4-Diaminobutane: purchased from Shanghai E. En Chemical Technology Co., Ltd.;

[0035] Ethylene-vinyl alcohol copolymer (ethylene molar content 32%): purchased from Shanghai Zhenzhun Biotechnology Co., Ltd.

[0036] Maleic anhydride-grafted polyethylene: purchased from Dongguan New Materials Co., Ltd.;

[0037] Polyethylene (PE) (DFDC7050): Purchased from Sinopec, with a melt flow rate of 2 g / 10 min at 190℃ and 2.15 kg (linear low-density polyethylene).

[0038] 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.

[0039] Preparation of the intermediate layer polymer (homemade):

[0040] Step S1: Dissolve monomers A and C in dimethyl sulfoxide (anhydrous) at a liquid-to-mass ratio of 5:1 (mL / g), add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), stir at 300 rpm for 2.5 h to obtain a carboxyl-activated solution.

[0041] Step S2: Dissolve monomer B in dimethyl sulfoxide (anhydrous) at a liquid-to-mass ratio of 4:1 (mL / g), and slowly add it to the carboxyl activation solution. Under nitrogen protection, stir and react for 3 hours. Add an equal volume of water to precipitate, filter and separate, wash with ethanol for purification, and dry under vacuum at 40°C to obtain the final product.

[0042] The molar ratio of monomers A, B, and C is (30-40):(80-95):(50-55). The molar ratio of EDC and NHS is 1:(0.8-1.2), and the amount of EDC used is 2.1 times the total molar amount of monomers A and B.

[0043] Table 1. Raw material ratios (molar ratios) for the intermediate layer polymer.

[0044]

[0045] Example 1

[0046] The outer PE material, the middle polymer 1 (middle layer material), and the outer PE material are fed into the extruder corresponding to the five-layer co-extrusion machine and made into a film through the co-extrusion process. The processing temperature is maintained at 160℃. Then, a corona treatment is performed using a corona machine to obtain a one-time molded all-plastic hose sheet.

[0047] The outer PE film has a thickness of 60 μm, the intermediate polymer intermediate layer has a thickness of 30 μm, and the inner PE film has a thickness of 250 μm.

[0048] The all-plastic flexible hose sheet is overlapped to form a tube body using a hose reel. The overlap is then subjected to induction heating and pressurized cooling using a high-frequency induction coil to produce a composite hose. The overlap size is 3mm. The induction heating temperature is 90℃, and the weld compression ratio after pressurization is 10%.

[0049] Example 2-3

[0050] The preparation methods and parameters of Examples 2-3 are exactly the same as those of Example 1, the only difference being that intermediate layer polymer 1 is replaced with intermediate layer polymer 2 and intermediate layer polymer 3 respectively.

[0051] Example 4

[0052] The outer PE material, the middle layer material (middle layer polymer 1, polyethylene, middle layer polymer 1), and the outer PE material are fed into the extruder corresponding to the five-layer co-extrusion machine. The film is formed by co-extrusion process, and the processing temperature is maintained at 160℃. Then, a corona treatment is performed using a corona machine to obtain a one-time molded all-plastic hose sheet.

[0053] The outer PE film has a thickness of 60 μm, the intermediate layer has a thickness of 60 μm (a three-layer composite intermediate layer consisting of an intermediate polymer 1 film, a polyethylene film, and an intermediate polymer 1 film, each with a thickness of 20 μm), and the inner PE film has a thickness of 250 μm.

[0054] The all-plastic flexible hose sheet is overlapped to form a tube body using a hose reel. The overlap is then subjected to induction heating and pressurized cooling using a high-frequency induction coil to produce a composite hose. The overlap size is 3mm. The induction heating temperature is 90℃, and the weld compression ratio after pressurization is 10%.

[0055] Example 5

[0056] The outer PE material, the intermediate layer material (intermediate layer polymer 1, ethylene-vinyl alcohol copolymer, intermediate layer polymer 1), and the outer PE material are fed into the extruder corresponding to the five-layer co-extrusion machine. The film is formed by co-extrusion process, and the processing temperature is maintained at 160℃. Then, a corona treatment is performed using a corona machine to obtain a one-time molded all-plastic hose sheet.

[0057] The outer PE film has a thickness of 60 μm, the intermediate layer has a thickness of 60 μm (a three-layer composite intermediate layer consisting of an intermediate layer polymer 1 film with a thickness of 20 μm, an ethylene-vinyl alcohol copolymer, and an intermediate layer polymer 1 film), and the inner PE film has a thickness of 250 μm.

[0058] The all-plastic flexible hose sheet is overlapped to form a tube body using a hose reel. The overlap is then subjected to induction heating and pressurized cooling using a high-frequency induction coil to produce a composite hose. The overlap size is 3mm. The induction heating temperature is 90℃, and the weld compression ratio after pressurization is 10%.

[0059] Comparative Examples 1-3

[0060] The preparation methods and parameters of Comparative Examples 1-3 are exactly the same as those of Example 1, except that the intermediate layer polymer 1 is replaced with the comparative polymers 1-3 respectively.

[0061] The resulting intermediate polymer layer, one-piece molded all-plastic hose sheet, and composite hose were subjected to the following performance tests.

[0062] (1) Tensile strength and elongation at break: The intermediate layer polymer (or the comparison polymer) was tested for tensile strength and elongation at break in accordance with GB / T1040.3-2006. Long strip specimens with a length of >150 mm and a width of 15 mm were used. The spacing between the specimen clamps was (100±5) mm, and the tensile speed (no load) was (200±20) mm / min.

[0063] (2) Interlayer peel strength: The interlayer peel strength of the one-piece molded all-plastic hose sheet is tested according to the method of the national light industry standard "All-plastic composite hose for toothpaste (QB / T4192-2011)" (unit: N / 15mm). The specific requirements are as follows: 1) Instrument used: universal tensile testing machine; 2) Take 3 to 5 material samples with a width of 15mm and a length of 150mm for testing, and take the average value; 3) Peel the delaminated sheet at a speed of 100mm / min. The force measured by the instrument is the required force. Since the inner and outer layers in the example and comparative example are the same PE film, and are directly composited with the middle layer, the peel strength of the inner and outer layers is not distinguished. Instead, the average value of the three peel strengths is taken.

[0064] (3) Water vapor barrier performance: The water vapor transmission of the composite hose was tested according to GB / T1037-1988 standard using a 3-33MA moisture translucency meter. 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.

[0065] (4) Oxygen barrier performance: The oxygen permeability of the composite hose was tested according to GB / T19789 standard. The specific test conditions were set as follows: test temperature: room temperature: 25℃, test pressure: 1atm, ambient humidity: 50%RH, test time: 24 hours; the sample was placed in a desiccator containing anhydrous calcium chloride or other desiccant for conditioning for no less than 48 hours.

[0066] (5) Water resistance: The water absorption rate (%) of the intermediate polymer (or the comparison polymer) was tested according to GB / T1034-2021 standard. The sheet thickness was 1 mm, and it was soaked in distilled water at 23℃ for 48 hours.

[0067]

[0068] According to the data in the table above, 1) the intermediate layer polymers, one-piece molded all-plastic hose sheets, or composite hoses involved in Examples 1-5 possess excellent mechanical strength, tensile strength, barrier properties, and peel resistance. 2) Compared with Example 1, Comparative Example 2 replaced monomer B with ethylenediamine instead of 1,5-diaminopentane. Since the carbon chain of ethylenediamine is shorter and linked to the amide bond, the molecular flexibility of the comparative polymer 1 is reduced and its rigidity is increased, affecting the formation of hydrogen bonds between molecules and the stacking effect between benzene rings. Consequently, the density of molecular stacking is reduced compared to Example 1, resulting in a significant decrease in the elongation at break, interlayer peel strength, and water vapor transmission / oxygen transmission ratio compared to Example 1. 3) Compared with Example 1, Comparative Example 2 used a polymer 2 that did not contain monomer A (2,6-dihydroxyisophthalic acid). Therefore, hydrogen bonds could not be formed between the molecules of Comparative Example 2, resulting in a significant decrease in tensile strength and barrier properties compared to Example 1. The reason why the interlayer peel strength of Comparative Example 2 was comparable to that of Example 1 was that the content of monomer C (4,4'-tetraphenylsilanedicarboxylic acid) was high, leading to a significant decrease in molecular hydrophilicity. Furthermore, the π-π stacking of the benzene rings enhanced the smoothness and bonding force of the interface, thereby increasing the interlayer peel strength with the PE layer. 4) Compared with Example 1, Comparative Example 3 used a polymer 3 that did not contain monomer C (4,4'-tetraphenylsilanedicarboxylic acid). This resulted in a relatively high content of monomer A in Comparative Example 3, allowing for the formation of numerous hydrogen bonds between molecules, thus increasing tensile strength and reducing oxygen permeability. Simultaneously, due to the relatively high content of monomer A in Comparative Example 3, the hydrophilicity of polymer 3 was significantly enhanced, leading to a significant decrease in interlayer peel strength and an increase in water vapor permeability.

[0069] 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. A one-piece molded all-plastic flexible hose sheet, characterized in that, It has a three-layer structure: an outer PE film, an intermediate layer, and an inner PE film; the intermediate layer is selected from an intermediate polymer layer or a three-layer composite layer formed by an intermediate polymer layer, a polyethylene layer, and an intermediate polymer layer, or a three-layer composite layer formed by an intermediate polymer layer, an ethylene-vinyl alcohol copolymer layer, and an intermediate polymer layer. The intermediate layer polymer is polymerized from monomer A: 2,6-dihydroxyisophthalic acid, monomer B: diaminoalkane, and monomer C: 4,4'-tetraphenylsilane. The method for preparing the intermediate layer polymer includes: Step S1: Dissolve monomers A and C in an organic solvent, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir for 1-4 h to obtain a carboxyl-activated solution; Step S2: Dissolve monomer B in an organic solvent and slowly add it to the carboxyl activation solution. Under nitrogen protection, stir the reaction for 2-5 hours, then separate, purify, and dry to obtain the product. The organic solvents used in steps S1 and S2 are selected from one of dimethyl sulfoxide, N,N-dimethylformamide, or N,N-dimethylacetamide; The molar ratio of monomers A, B, and C is (30-40):(80-95):(50-55); The molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to N-hydroxysuccinimide is 1:(0.8-1.2).

2. The one-piece molded all-plastic flexible hose sheet according to claim 1, characterized in that, The diaminoalkane is selected from one of 1,7-diaminoheptane, 1,5-diaminopentane, 1,6-diaminohexane, and 1,4-diaminobutane.

3. A composite flexible hose, characterized in that, It includes a tube body made from a one-piece molded all-plastic flexible tube sheet as described in any one of claims 1-2.

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