A culture tube, its preparation method and application

Abstract

The application belongs to the technical field of pipes, and particularly discloses a breeding pipe and a preparation method and application thereof. The breeding pipe has a three-layer structure, and comprises, from inside to outside, a protective layer, a middle layer and an anti-attachment layer. The layers are firm and not easy to delaminate, can meet the structural safety required by the breeding pipe, and have a high anti-attachment shelf life and can effectively prevent marine organisms from attaching.

Description

Technical Field

[0001] This invention belongs to the field of pipe technology, specifically relating to an aquaculture pipe, its preparation method, and its application. Background Technology

[0002] Currently, the materials used for aquaculture racks in China, such as oyster rafts, are mostly made of fir wood and bamboo. These materials have simple structures and weak resistance to wind and waves. Furthermore, the good biocompatibility of fir wood and bamboo makes it easy for marine organisms to accumulate on their surfaces, causing them to bear extra weight and eventually break, resulting in losses for farmers and seriously affecting the development of oyster and other aquaculture industries.

[0003] Patent document CN113956763A discloses a coating for preventing marine bioattachment and its preparation method. This coating uses additives and a metallic antibacterial agent to reduce the biocompatibility of the material surface, killing easily attaching organisms. Simultaneously, the biodegradable resin, containing polar groups, has good adhesion to metals, and the lactic acid produced after hydrolysis further reduces the material's biocompatibility, decreasing bioattachment. However, the microorganisms killed by the additives and metallic antibacterial agent adhere to the material surface, leading to a decrease in the anti-bioattachment performance, and subsequent microbial accumulation may still occur.

[0004] Patent document CN106189542A discloses a marine organism-repellent coating and its preparation method. It achieves the ability to prevent marine organisms from attaching by adding additives that are disliked by marine fouling organisms such as barnacles, mussels, and algae. However, other microorganisms in the ocean can also easily accumulate and form a barrier layer, which in turn leads to the attachment of barnacles, mussels, etc.

[0005] Therefore, there is still a need to develop an aquaculture rack material that can effectively prevent marine organisms from attaching, ensuring aquaculture safety and having significant economic benefits. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings or deficiencies of the prior art and to provide an aquaculture tube, its preparation method and application, so as to ensure the safety and anti-bioadhesion properties of the aquaculture tube.

[0007] To achieve the above objectives, the following technical solutions are specifically included:

[0008] A type of aquaculture tube, comprising, from the inside out, a protective layer, an intermediate layer, and an anti-adhesion layer.

[0009] The protective layer comprises 95-105 parts by weight of polypropylene and 0.1-5 parts by weight of processing aids.

[0010] The intermediate layer comprises 90-105 parts by weight of polypropylene and 0.1-5 parts by weight of low molecular weight additives, wherein the low molecular weight additives include at least one of erucamide and oleamide.

[0011] The anti-adhesion layer comprises 80-95 parts by weight of polypropylene, 5-15 parts by weight of a polar substance, and 0.1-2 parts by weight of an anti-adhesion additive. The polar substance comprises at least one of maleic anhydride-grafted PP and maleic anhydride-grafted PE, and the anti-adhesion additive comprises at least one of polysiloxane and polytetrafluoroethylene.

[0012] The aquaculture tube of this invention has a three-layer structure, comprising a protective layer, an intermediate layer, and an anti-adhesion layer from the inside out. The anti-adhesion layer contains an anti-adhesion additive that forms a protective layer on the surface of the aquaculture tube, effectively preventing the attachment of marine organisms. At the same time, a low-molecular-weight additive is added to the intermediate layer, which can be attracted by the polar substances in the anti-adhesion layer to continuously migrate to the surface of the material to form a new protective layer, providing a long-term and effective anti-adhesion effect. The protective layer can prevent the low-molecular-weight additive in the intermediate layer from migrating to the surface, thereby improving the anti-adhesion effect.

[0013] In the protective layer of the present invention, the mass percentage of polypropylene is preferably not less than 80%, more preferably not less than 90% or 95%.

[0014] In the protective layer of the present invention, the weight parts of polypropylene can be 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0015] In the intermediate layer of the present invention, the mass percentage of polypropylene is preferably not less than 80%, and more preferably not less than 90%.

[0016] In the intermediate layer of this invention, the weight parts of polypropylene can be 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, etc., as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0017] In the anti-adhesion layer of the present invention, the mass percentage of polypropylene is preferably not less than 70%, and more preferably not less than 80%.

[0018] In the anti-adhesion layer of the present invention, the weight parts of polypropylene can be 80, 81, 82, 83, 84, 85, 86, 87, 89, 90, 91, 92, 93, 94, 95, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0019] The weight parts of the low molecular weight additive can be 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5, etc., as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0020] In a preferred embodiment of the present invention, the mass ratio of erucamide to oleamide is (1-4):1.

[0021] The inventors of this invention have discovered that when erucamide and oleamide are compounded in a weight ratio of (1-4):1, they can work together to improve the anti-adhesion effect due to their different migration rates.

[0022] The weight parts of the polar substance can be 5, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, etc., as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0023] In a preferred embodiment of the present invention, the grafting rate of maleic anhydride-grafted PP is 0.7-1.2%.

[0024] In a preferred embodiment of the present invention, the grafting rate of the maleic anhydride-grafted PE is 0.7-1.2%.

[0025] The grafting rate of maleic anhydride grafts has a certain impact on the adhesion effect of the aquaculture tubes. When the above-mentioned grafting rate is optimized, the adhesion effect of the aquaculture tubes is better.

[0026] There are no particular limitations on the weight-average molecular weight of polysiloxanes. For example, the weight-average molecular weight of polysiloxanes can be selected from 100,000 to 2,000,000, which can be obtained by gel permeation chromatography.

[0027] The weight parts of the anti-adhesion additive can be 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, etc., as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0028] The melt flow rate of polypropylene in the protective layer, intermediate layer, or anti-adhesion layer of this invention is not particularly limited. At least one of conventional homopolymer polypropylene and copolymer polypropylene can be used. Polypropylene with conventional melt flow rate can be used, such as polypropylene with a melt flow rate of 0.2-1.0 g / 10 min at 230°C and 2.16 kg according to ISO 1133-2005 standard. Within this range, the flexural modulus and tensile strength of the material can be better.

[0029] In a preferred embodiment of the present invention, the intermediate layer further includes 0.1-1 parts by weight of a processing aid.

[0030] In a preferred embodiment of the present invention, the processing aid includes 0.1-5 parts by weight of an antioxidant.

[0031] The thicknesses of the anti-adhesion layer, intermediate layer, and protective layer can be adjusted according to the actual situation. For example, the ratio of the thicknesses of the anti-adhesion layer, intermediate layer, and protective layer can be selected as (0.5-1.5):(2-4):(0.5-1.5).

[0032] The present invention also provides a method for preparing the aforementioned aquaculture tube, comprising the following steps:

[0033] The raw materials for the protective layer, intermediate layer, and anti-adhesion layer are mixed separately; the protective layer, intermediate layer, and anti-adhesion layer are prepared sequentially by extrusion; and then the layers are subjected to vacuum sizing and cooling to obtain the aquaculture tube.

[0034] The aquaculture tube of the present invention has tightly attached layers and good anti-adhesion properties. The aquaculture tube can be used in shellfish aquaculture, specifically in the aquaculture of oysters, mussels and other shellfish.

[0035] Compared with the prior art, the present invention has the following beneficial effects: The aquaculture tube of the present invention has a three-layer structure, which includes a protective layer, an intermediate layer and an anti-attachment layer from the inside out. Each layer is structurally robust and not easy to delaminate, which can meet the structural safety requirements of the aquaculture tube. At the same time, the anti-attachment effect is highly effective and can effectively prevent marine organisms from attaching. Detailed Implementation

[0036] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0037] The raw materials used in the embodiments and comparative examples of this invention are all commercially available.

[0038] Polypropylene: The following melt flow rates were all tested at 230℃ and 2.16kg: 0.2g / 10min PP, grade: PP D50S, Tianjin United; 1.0g / 10min PP, grade: PP K1101, Yanshan Petrochemical.

[0039] Processing aids: a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of the two is 1:1;

[0040] Low molecular weight additives: Erucamide and oleamide are both commercially available;

[0041] Polar substances: maleic anhydride-grafted PP, grafting rate 0.8%, grade FH118A, manufacturer Ningbo Nengzhiguang; maleic anhydride-grafted PP, grafting rate 1.2%, grade Fine-Blend FB122, manufacturer Shanghai Jiayirong;

[0042] Anti-adhesion agent: Polysiloxane with a weight average molecular weight of 1,650,000, brand name GT-300, effective content of 55 wt.%, Zhejiang Jiahua; Polytetrafluoroethylene, SN80-SA7 (containing 50 wt.% processing aids of polytetrafluoroethylene).

[0043] Examples 1-15 and Comparative Examples 1-7

[0044] Preparation methods of culture tubes in Examples 1-15 and Comparative Examples 1-7:

[0045] (1) Weigh the raw materials according to Tables 1 and 2, and mix the raw materials of each layer separately;

[0046] (2) The mixture of each layer after mixing is fed into the first, second and third screw extruders in sequence. The protective layer is extruded through the first twin-screw extruder, the intermediate layer is applied to the protective layer through the second screw extruder, and the anti-adhesion layer is applied to the intermediate layer through the third twin-screw extruder. The processing temperature of each screw extruder is set to 190-210℃. Then, the mixture is vacuum sizing and cooling to obtain the breeding tube. The thickness of the breeding tube is 1cm, and the thickness ratio of the protective layer, intermediate layer and anti-adhesion layer is 1:3:1.

[0047] The aquaculture tubes prepared in the examples and comparative examples were subjected to performance tests, and the specific methods are as follows:

[0048] The aquaculture tubes prepared in the examples and comparative examples were placed on a rotating waterwheel and placed in the seawater of Shenzhen Bay for one year. The tubes were rotated continuously for 12 hours and stopped for 12 hours, and this was used as one cycle for rotation. The linear velocity of the sample during rotation was 10 km / hr. The tubes could be taken out at regular intervals to observe the surface and evaluate the bio-attachment effect. When the bio-attachment effect exceeded 10% of the surface area of ​​the aquaculture tube, it was considered as the anti-attachment failure time, and the number of days of anti-attachment effectiveness was recorded. At the same time, the adhesion between each layer was observed, and whether there was any delamination phenomenon was observed.

[0049] Table 1 (by weight)

[0050]

[0051] Table 2 (by weight)

[0052]

[0053] As can be seen from the above embodiments, the anti-adhesion effect of the aquaculture tube of the present invention is greater than 365 days, and the protective layer, intermediate layer and anti-adhesion layer are tightly attached and not easy to delaminate.

[0054] As can be seen from Examples 1-3 and Comparative Examples 1-2 and 7, the present invention adds low molecular weight additives to the intermediate layer, which, together with the polar substances in the anti-adhesion layer, allows the low molecular weight additives to continuously migrate to the material surface, serving as the second and third protective layers on the surface, providing a long-term and effective anti-adhesion effect, and playing the role of providing effective additives to the anti-adhesion layer for a long time. However, the low molecular weight additives should not be excessive, otherwise it will affect the adhesion between the intermediate layer and other layers, causing the intermediate layer to detach from the other layers.

[0055] As shown in Examples 1 and 4-7, the low molecular weight additive can be either erucamide or oleamide, and the protective effect is better when erucamide and oleamide are compounded in a weight ratio of (1-4):1. This may be due to the different migration rates of the two. Oleamide is more likely to migrate out of the material surface to form the outermost protective layer, which improves the anti-adhesion performance. When compounded, the migration rates of oleamide and erucamide complement each other, and the continuous migration effect is longer, resulting in better protection of the aquaculture pipe.

[0056] As can be seen from Examples 1, 8-9 and Comparative Examples 3-4, adding polysiloxane or polytetrafluoroethylene to the anti-attachment layer first forms a protective layer on the surface of the aquaculture tube, which can improve the effect of preventing marine organisms from attaching. However, the amount should not be too much. Excessive use will lead to poor adhesion between the anti-attachment layer and other layers of the aquaculture tube, resulting in delamination.

[0057] As demonstrated in Examples 1, 11-13, and Comparative Examples 5-6, adding polar substances to the anti-adhesion layer can provide a long-term effective anti-adhesion effect. This may be because the polar substances can induce the low-molecular-weight additives in the intermediate layer to migrate directionally to the anti-adhesion layer, attracting them to continuously migrate to the material surface to form a second and third protective layer. Simultaneously, the intermediate protective layer prevents excessive low-molecular-weight additives from migrating into the sea, causing them to be lost and ineffective. However, excessively high levels of polar substances may actually promote the attachment of marine organisms, resulting in poor anti-adhesion performance. Furthermore, the grafting rate of the maleic anhydride graft has a certain influence on the polarity of the polar substance, which in turn affects the adhesion effect on the aquaculture tube. Therefore, a grafting rate of 0.7-1.2% for the polar substance is preferred.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A raceway, characterized in that, from inside to outside in turn include a protective layer, an intermediate layer, an anti-adhesion layer, The protective layer includes 95-105 parts by weight of polypropylene and 0.1-5 parts by weight of a processing aid; The intermediate layer includes 90-105 parts by weight of polypropylene and 0.1-5 parts by weight of a low molecular weight aid, the low molecular weight aid including at least one of erucic acid amide and oleic acid amide; The anti-adhesion layer includes 80-95 parts by weight of polypropylene, 5-15 parts by weight of a polar substance and 0.1-2 parts by weight of an anti-adhesion aid, the polar substance including at least one of maleic anhydride grafted PP and maleic anhydride grafted PE, the anti-adhesion aid including at least one of polysiloxane and polytetrafluoroethylene.

2. The raceway of claim 1 wherein, The mass ratio of the erucic acid amide and the oleic acid amide is (1-4):

1.

3. The raceway of claim 1 wherein, The grafting rate of the maleic anhydride grafted PP and / or the maleic anhydride grafted PE is 0.7-1.2%.

4. The raceway of claim 1 wherein, The melt flow rate of the polypropylene is 0.2-1.0 g / 10 min under the condition of 230℃ and 2.16 kg according to the ISO 1133-2005 standard.

5. The raceway of claim 1 wherein, The intermediate layer further includes 0.1-1 parts by weight of a processing aid.

6. The rearing tube according to claim 1 or 5, wherein The processing aid includes an antioxidant.

7. A method of producing the culture tube according to any one of claims 1 to 6, characterized by, The method includes the following steps: The raw materials of the protective layer, the intermediate layer and the anti-adhesion layer are mixed respectively; the protective layer, the intermediate layer and the anti-adhesion layer are prepared in turn by extrusion; and then the protective layer, the intermediate layer and the anti-adhesion layer are sequentially subjected to vacuum sizing and cooling to obtain the breeding pipe.

8. Application of the breeding pipe according to any one of claims 1-6 in breeding of shellfish.

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