Reinforced HDPE (high-density polyethylene) marine aquaculture pipe as well as preparation method and application thereof

Abstract

The invention discloses a reinforced HDPE (high-density polyethylene) marine aquaculture pipe as well as a preparation method and application thereof, and relates to the technical field of marine cage culture, the HDPE marine aquaculture pipe comprises an HDPE core layer, a barrier layer and an HDPE outer layer which are sequentially connected from inside to outside in the radial direction; and the barrier layer is formed by an ethylene-vinyl alcohol copolymer. According to the HDPE marine aquaculture pipe, a barrier layer formed by ethylene-vinyl alcohol copolymer is arranged between two layers of HDPE pipes, and the section of the pipe is of a sandwich ring structure; the barrier layer formed by EVOH has good mechanical strength and toughness and can be matched with the HDPE core layer and the HDPE outer layer, stress distribution of the HDPE core layer and the HDPE outer layer is buffered and improved, the overall compressive strength and puncture resistance of the pipe are improved, particularly, the gas permeability of the EVOH barrier layer is low, water inside and outside the pipe can be effectively prevented from seeping from fractured pipe wall cracks, and the service life of the pipe is prolonged. The practicability and the durable life of the product are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of marine cage aquaculture, and more specifically, to a reinforced HDPE marine aquaculture pipe and a preparation method and application thereof. Background Art

[0002] At present, the HDPE marine aquaculture pipes used to build marine aquaculture cages are generally single-layer polyethylene pipes. The pipes are made of high-density polyethylene (HDPE) and are mainly used in shallow sea areas. They are extruded and cooled by equipment, and the pipes are connected by hot-melt welding. They have high toughness and can withstand certain impacts. However, if they need to be used in deep sea areas outside shallow sea areas, their strength and leak-proof effect still need to be improved.

[0003] The marine environment in the deep sea is complex. Under the impact of waves and deep sea water pressure for a long time, cage aquaculture pipes are easily punctured and burst. Once the pipe is damaged and leaks, it will cause different losses to users. It is urgent to study a HDPE cage aquaculture pipe that is explosion-proof, leak-proof, and puncture-resistant in the deep sea environment.

[0004] Patent CN209330911U proposes a pipe assembly for floating deep-sea cages, in which a HDPE sealing plate is fixedly sealed at the proximal end of the two axial ends of the HDPE pipe, and a sealed cylindrical filling space is formed between the HDPE sealing plates at the two axial ends and the DPE pipe. The EPS foam rod is coaxially and fixedly filled in the cylindrical filling space, so that it has high ring stiffness, strong external pressure resistance, and is not easy to sink. Although the filling of EPS foam rods in the HDPE pipe improves the external pressure resistance to a certain extent, the operation cost is relatively high, and its anti-leakage and puncture resistance performance still need to be improved. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of existing cage aquaculture pipes in the deep sea environment, such as poor burst resistance, leakage resistance and puncture resistance, and to provide a HDPE marine aquaculture pipe.

[0006] The purpose of the invention is to provide a method for preparing a HDPE marine aquaculture pipe.

[0007] The object of the present invention is to provide the use of the above-mentioned HDPE marine aquaculture pipe in the preparation of deep-sea aquaculture cages.

[0008] The object of the present invention is to provide a deep-sea aquaculture cage constructed by the above-mentioned HDPE marine aquaculture pipe.

[0009] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0010] The present invention protects a HDPE marine aquaculture pipe, comprising a HDPE core layer, a barrier layer and a HDPE outer layer which are sequentially connected from the inside to the outside along the radial direction;

[0011] The mass content of the barrier layer accounts for 20-40% of the mass of the multilayer composite pipe;

[0012] The material of the HDPE core layer and the HDPE outer layer is HDPE, and the melt mass flow rate of the HDPE at 230° C. and 2.16 kg is 1.7-2.2 g / 10 min;

[0013] The barrier layer is made of ethylene-vinyl alcohol copolymer, and the melt mass flow rate of the ethylene-vinyl alcohol copolymer is 1.8-2.2 g / 10 min at 230° C. and 2.16 kg. The test standard for the melt mass flow rate of the present invention is ISO 1133-1-2011.

[0014] The HDPE marine aquaculture pipe of the present invention is formed by arranging a barrier layer formed by ethylene-vinyl alcohol copolymer (EVOH) between two layers of HDPE pipes, and the pipe cross-section presents a sandwich ring structure; the barrier layer formed by EVOH has good mechanical strength and toughness, and at the same time optimizes the melt mass flow rate of each layer of material, so that the EVOH layer can cooperate with the HDPE core layer and the HDPE outer layer, buffer and improve the stress distribution of the HDPE core layer and the HDPE outer layer, and improve the overall compressive strength and puncture resistance of the pipe; in particular, the EVOH barrier layer has excellent gas permeability, and can effectively prevent water inside and outside the pipe from seeping out from cracks in the broken pipe wall, thereby improving the practicability and durability of the product.

[0015] In some embodiments, the barrier layer accounts for 22-38% of the mass of the multi-layer composite pipe.

[0016] In some embodiments, the mass content of the HDPE core layer accounts for 35-45% of the mass of the multi-layer composite pipe.

[0017] In some embodiments, the mass content of the HDPE outer layer accounts for 25-35% of the mass of the multi-layer composite pipe.

[0018] In some embodiments, the mass ratio of the HDPE core layer, the barrier layer and the HDPE outer layer is (3-5):(2-4):(2-4). Preferably, the mass ratio is 4:(2-4):3.

[0019] Among them, the mass content of each layer has a certain influence on the improvement of the overall performance. Too much or too little mass ratio of each layer will affect the synergistic effect of each layer to a certain extent, thereby affecting the overall anti-burst, anti-leakage and puncture resistance performance of the multi-layer composite pipe.

[0020] In some embodiments, the barrier layer is formed by stacking two or more barrier monolayers.

[0021] In some embodiments, the number of the barrier monolayers is 2-5.

[0022] In some embodiments, the barrier layer is formed by stacking a first barrier monolayer and a second barrier monolayer, and the mass ratio of the first barrier monolayer to the second barrier monolayer is (0.9-1.1):1.

[0023] In some embodiments, the water vapor permeability of the HDPE marine aquaculture pipe is 3.4 g / m 2 ·24 hours or less, puncture resistance is 24N or more.

[0024] The present invention provides a method for preparing a HDPE marine aquaculture pipe, comprising the following steps:

[0025] S1, extrusion to form a HDPE core layer tube;

[0026] S2, extruding ethylene-vinyl alcohol copolymer and covering the surface of the HDPE core layer tube to form a barrier layer of ethylene-vinyl alcohol copolymer;

[0027] S3, after the barrier layer is coated with the adhesive coating, it is heated by a heating device and then coated with an HDPE outer layer.

[0028] The barrel temperature of the production machine should be 210-230℃, the die head temperature should be 190-210℃, and the heating device temperature should be 120-140℃.

[0029] The present invention protects the use of a HDPE marine aquaculture pipe in the preparation of deep-sea aquaculture cages.

[0030] The invention protects a deep sea aquaculture cage which is constructed by HDPE marine aquaculture pipes.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention provides a HDPE marine aquaculture pipe material. A barrier layer formed by ethylene-vinyl alcohol copolymer (EVOH) is arranged between two layers of HDPE pipes, and the pipe cross section presents a sandwich ring structure. The barrier layer formed by EVOH has good mechanical strength and toughness, and at the same time optimizes the melt mass flow rate of each layer of material. The EVOH layer can cooperate with the HDPE core layer and the HDPE outer layer to buffer and improve the stress distribution of the HDPE core layer and the HDPE outer layer, thereby improving the overall compressive strength and puncture resistance of the pipe material. In particular, the EVOH barrier layer has excellent gas permeability, and can effectively prevent water inside and outside the pipe from seeping out from cracks in the broken pipe wall, thereby improving the practicability and durability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic structural diagram of a HDPE marine aquaculture pipe according to the present invention.

[0034] 1. HDPE core layer; 2. Barrier layer; 3. HDPE outer layer. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0036] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent.

[0037] The raw materials used in the following examples and comparative examples are as follows:

[0038] High-density polyethylene (HDPE):

[0039] HDPE-1: HE3490LSH, Borouge Middle East; its melt mass flow rate at 230℃ and 2.16Kg is 1.95g / 10min.

[0040] HDPE-2: M6080WC, Dongguan Dongli Plastic Raw Materials Co., Ltd.; its melt mass flow rate at 230°C and 2.16Kg is 1.82g / 10min.

[0041] HDPE-3: TR-480BL, YeSu International Trading Co., Ltd.; its melt mass flow rate at 230°C and 2.16Kg is 1.62g / 10min.

[0042] Ethylene vinyl alcohol copolymer (EVOH):

[0043] EVOH-1: 25067-34-9, Hubei Nona Company; its melt mass flow rate is 2.05g / 10min at 230℃ and 2.16Kg.

[0044] EVOH-2: F104B, Dongguan Xiaoma Plastic Technology Co., Ltd.; its melt mass flow rate is 1.87g / 10min at 230℃ and 2.16Kg.

[0045] EVOH-3: H171B, Dongguan Baojia Plastic Co., Ltd.; its melt mass flow rate at 230°C and 2.16Kg is 1.66g / 10min.

[0046] Example 1

[0047] A HDPE marine aquaculture pipe, such as Figure 1 As shown, it includes a HDPE core layer 1, a barrier layer 2 formed by ethylene-vinyl alcohol copolymer and a HDPE outer layer 3 which are connected in sequence from the inside to the outside along the radial direction; the mass ratio of the HDPE core layer 1, the barrier layer 2 and the HDPE outer layer 3 is 4:3:3, and the inner diameter specification is 400mm.

[0048] The material of the HDPE core layer 1 is HDPE-1;

[0049] The material of barrier layer 2 is EVOH-1;

[0050] The material of the HDPE outer layer 3 is HDPE-1;

[0051] The barrier layer 2 is formed by stacking two barrier single layers with the same thickness.

[0052] The method for preparing the HDPE marine aquaculture pipe comprises the following steps:

[0053] (1) Using an extruder to extrude the inner layer of the HDPE core tube;

[0054] (2) After the HDPE core tube is heated by a heat drying device, two layers of ethylene-vinyl alcohol copolymer are extruded and covered on the HDPE core tube by a co-extruder, and the thickness of the two layers is 0.2-0.5 mm, and the two layers of ethylene-vinyl alcohol copolymer are fully bonded with an adhesive layer to form an EVOH barrier layer 2;

[0055] (3) A layer of adhesive layer is coated on the surface of the EVOH barrier layer 2 by an auxiliary extruder, and then a layer of HDPE outer layer 3 is coated on the adhesive surface by an extruder to obtain the HDPE marine aquaculture pipe.

[0056] The present invention adopts an EVOH barrier layer 2 with an intermediate double-layer structure in combination with an inner and outer HDPE pipe, which can improve the overall strength of the pipe, and prolong the service life of the pipe while preventing damage from external factors.

[0057] Example 2

[0058] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the HDPE core layer 1 and the HDPE outer layer 3 is HDPE-2.

[0059] Example 3

[0060] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the HDPE core layer 1 is HDPE-2, and the material of the HDPE outer layer 3 is HDPE-1.

[0061] Example 4

[0062] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the barrier layer 2 is EVOH-2.

[0063] Example 5

[0064] A HDPE marine aquaculture pipe is different from Example 1 in that the mass ratio of the HDPE core layer 1, the barrier layer 2 and the HDPE outer layer 3 is 4:2:3.

[0065] Example 6

[0066] A HDPE marine aquaculture pipe, which is different from Example 1 in that the mass ratio of the HDPE core layer 1, the barrier layer 2 and the HDPE outer layer 3 is 4:4:3.

[0067] Comparative Example 1

[0068] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the HDPE core layer 1 and the HDPE outer layer 3 is HDPE-3.

[0069] Comparative Example 2

[0070] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the barrier layer 2 is EVOH-3.

[0071] Comparative Example 3

[0072] A HDPE marine aquaculture pipe, which is different from Example 1 in that the material of the barrier layer 2 is HDPE-1.

[0073] Comparative Example 4

[0074] A HDPE marine aquaculture pipe is different from Example 1 in that the mass ratio of the HDPE core layer 1, the barrier layer 2 and the HDPE outer layer 3 is 4:1:3.

[0075] Comparative Example 5

[0076] A HDPE marine aquaculture pipe is different from Example 1 in that the mass ratio of the HDPE core layer 1, the barrier layer 2 and the HDPE outer layer 3 is 4:5:3.

[0077] Performance Testing

[0078] 1. Hydraulic strength test

[0079] The HDPE marine aquaculture pipes of Examples 1-6 and Comparative Examples 1-5 were subjected to hydraulic strength resistance tests, and the results are shown in Table 1.

[0080] The test method is to test according to GB / T 13663.2-2018, and test the tolerance time of 80°C hydraulic pressure in a specific pressure range (mainly two pressure types, SDR13 and SDR17).

[0081] 2. Water vapor transmission rate

[0082] The water vapor permeability of the HDPE marine aquaculture pipes of Examples 1-6 and Comparative Examples 1-5 was tested, and the results are shown in Table 1. The water vapor permeability test method is GB1037-1988 Plastic film and sheet water vapor permeability test method (cup method) or GB / T26253-2010 Determination of water vapor permeability infrared detector.

[0083] 3. Puncture resistance test

[0084] The HDPE marine aquaculture pipes of Examples 1-6 and Comparative Examples 1-5 were tested for puncture resistance, and the results are shown in Table 1. The puncture resistance test method is GB / T37841-2019 Plastic Film and Sheet Puncture Resistance Test Method.

[0085] 4. Elongation at break and flexural strength

[0086] The HDPE marine aquaculture pipes of Examples 1-6 and Comparative Examples 1-5 were tested for elongation at break and bending strength, and the results are shown in Table 1. The test method for the elongation at break and the bending strength was tested according to the method of GB / T13663.2-2018.

[0087] Table 1

[0088]

[0089]

[0090] It can be seen from Table 1 that the HDPE marine aquaculture pipe of the present invention has high hydraulic strength resistance, is not broken under 80°C hydraulic pressure for 1000h, and has a water vapor transmission rate of less than 3.4g / m 2 ·24h, puncture resistance 24N or more, elongation at break 300% or more, bending strength 32Mpa or more.

[0091] In Comparative Example 1, the melt mass flow rate of the HDPE core layer and the HDPE outer layer is too low, and the hydraulic strength and water vapor permeability of the material are significantly reduced.

[0092] In Comparative Example 2, the melt mass flow rate of the barrier layer EVOH is too low, and the hydraulic strength and water vapor transmission rate of the material are also reduced.

[0093] In Comparative Example 3, no EVOH barrier layer was added, and the hydraulic resistance, water vapor permeability, elongation at break and bending strength of the material were significantly reduced.

[0094] When the content of the EVOH barrier layer in Comparative Examples 4-5 is too low or too high, the hydraulic strength and water vapor permeability of the material decrease.

[0095] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A HDPE marine aquaculture pipe, characterized in that: It includes a HDPE core layer, a barrier layer and a HDPE outer layer which are sequentially connected from the inside to the outside in radial direction; The mass content of the barrier layer accounts for 20-40% of the mass of the multilayer composite pipe; The melt mass flow rate of the HDPE core layer and the HDPE outer layer under the conditions of 230°C and 2.16Kg is 1.7-2.2g / 10min; The barrier layer is made of ethylene-vinyl alcohol copolymer, and the melt mass flow rate of the ethylene-vinyl alcohol copolymer is 1.8-2.2 g / 10 min at 230° C. and 2.16 kg.

2. The HDPE marine aquaculture pipe according to claim 1, characterized in that: The mass content of the barrier layer accounts for 22-38% of the mass of the multi-layer composite pipe.

3. The HDPE marine aquaculture pipe according to claim 1, characterized in that: The mass ratio of the HDPE core layer, the barrier layer and the HDPE outer layer is (3-5): (2-4): (2-4).

4. The HDPE marine aquaculture pipe according to claim 1, characterized in that: The barrier layer is formed by stacking two or more barrier single layers.

5. The HDPE marine aquaculture pipe according to claim 4, characterized in that: The number of the barrier monolayers is 2-5.

6. The HDPE marine aquaculture pipe according to claim 4, characterized in that: The barrier layer is formed by stacking a first barrier monolayer and a second barrier monolayer, and the mass ratio of the first barrier monolayer to the second barrier monolayer is (0.8-1.2):

1.

7. The HDPE marine aquaculture pipe according to any one of claims 1 to 6, characterized in that: The water vapor permeability of the HDPE marine aquaculture pipe is 3.4g / m 2 ·24 hours or less, puncture resistance is 24N or more.

8. A method for preparing the HDPE marine aquaculture pipe according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, extrusion to form a HDPE core layer tube; S2, extruding ethylene-vinyl alcohol copolymer and covering the surface of the HDPE core layer tube to form a barrier layer of ethylene-vinyl alcohol copolymer; S3, after the barrier layer is coated with the adhesive coating, it is coated with a HDPE outer layer.

9. Use of the HDPE marine aquaculture pipe according to any one of claims 1 to 6 in the preparation of deep-sea aquaculture cages.

10. A deep sea aquaculture cage, characterized in that: It is constructed from the HDPE marine aquaculture pipe described in any one of claims 1 to 6.

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