An antimicrobial adherent underwater laid cable jacket material and its preparation and surface modification process

Abstract

This invention relates to the field of cable material technology, and in particular to an antimicrobial adhesion underwater cable sheath material and its preparation and modification process. It comprises the following components in parts by weight: 60-65 parts LLDPE; 10-15 parts PP; 8-12 parts PVDF; 8-12 parts EVA; 0.3-0.5 parts mixed antioxidant; and 0.1-0.3 parts mixed lubricant. This invention utilizes a quaternary blend system of LLDPE, PP, low molecular weight PVDF, and EVA, combined with a highly efficient antioxidant and lubricant, to give the sheath material excellent water resistance, aging resistance, and antimicrobial adhesion properties. After activation by 360° annular plasma under constant pressure, a hydrophilic hydration layer of HEMA and NVP is grafted onto the sheath surface, which effectively inhibits microbial adhesion and biofilm formation, significantly extending the service life of underwater cables.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, and in particular to an antimicrobial adhesion underwater cable sheath material and its preparation and surface modification process. Background Technology

[0002] Underwater cables are constantly immersed in aquatic environments, making their sheath surfaces susceptible to adhesion and biofilm formation by bacteria, algae, and other microorganisms. The acidic substances produced by biofilm metabolism corrode the sheath surface, leading to microcracks, water seepage, and additive loss, ultimately causing decreased insulation performance, sheath aging and cracking, and severely shortening the cable's lifespan. Currently, underwater cable sheaths mostly use polyolefin materials, but these have the following drawbacks: high surface energy, making them prone to microbial adhesion and exhibiting poor resistance to microbial adhesion; they are prone to aging and hydrolysis under long-term immersion, resulting in rapid degradation of mechanical and insulation properties; existing surface modification technologies often employ single-monomer grafting or single-plasma activation, leading to uneven activation, low grafting efficiency, and poor stability of the modified layer, making it difficult to meet the requirements for long-term stable underwater operation. When using PVDF to modify polyolefin sheaths, medium- and high molecular weight PVDF suffers from poor dispersibility and processing difficulties; plasma activation often uses a single-nozzle structure, failing to achieve 360° omnidirectional activation; and grafting solutions often use single monomers, resulting in slow grafting rates and susceptibility to self-polymerization at high temperatures. Therefore, how to provide an underwater cable sheath material and modification process that is reasonably formulated, has good processability, is water-resistant and aging-resistant, has excellent antimicrobial adhesion properties, and has supporting processes that can be continuously produced industrially is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that existing underwater cable sheath materials have poor resistance to microbial adhesion, are prone to aging after long-term immersion in water, have uneven surface modification and activation, low grafting efficiency, and are difficult to achieve industrial continuous production.

[0004] The technical solution adopted by the present invention to solve its technical problem is: an antimicrobial adhesion underwater cable sheath material, which is composed of the following components in parts by weight: 60-65 parts LLDPE; 10-15 parts PP; 8-12 parts PVDF; 8-12 parts EVA; 0.3-0.5 parts mixed antioxidant; and 0.1-0.3 parts mixed lubricant.

[0005] Furthermore, the molecular weight of PVDF is 100,000 to 200,000.

[0006] Furthermore, the mixed antioxidant is composed of 3114 and PEP-36 in a mass ratio of 1:1, and the mixed lubricant is composed of PETS and PPA in a mass ratio of 2:1.

[0007] Furthermore, the composition is as follows: 62 parts LLDPE, 12 parts PP, 10 parts PVDF, 10 parts EVA, 0.4 parts mixed antioxidant, and 0.2 parts mixed lubricant.

[0008] Furthermore, the preparation method of the sheath material includes: drying PVDF powder in an oven at 80℃ for 4 hours, and drying LLDPE, PP, and EVA for 2 hours respectively; adding each component to a high-speed mixer according to the formula ratio, and mixing for 15-20 minutes at 80-90℃ and 300-400 r / min to obtain a mixture; feeding the mixture into a twin-screw extruder, setting the extrusion temperature to 200-220℃ and the screw speed to 150-200 r / min, and extruding and granulating to obtain sheath material particles.

[0009] Furthermore, an antimicrobial adhesion underwater cable includes a cable core and a sheath covering the outer periphery of the cable core. The sheath is made of the aforementioned sheath material, and the surface of the sheath is grafted with a hydrophilic hydration layer containing HEMA and NVP after being activated by a 360° annular cyclone plasma.

[0010] Furthermore, the atmospheric pressure 360° annular rotary plasma activation uses four nozzles arranged in a cross-shaped symmetrical ring, with the nozzles tilted 10°~15° towards the center and converging. It uses 99.99% high-purity argon as the sole gas supply, with a total gas flow rate of 20~24L / min, a gas supply pressure of 0.25~0.35MPa, a single nozzle power of 150W, an operating frequency of 30~50kHz, a nozzle distance of 10mm from the cable surface, and an activation time of 18~30s.

[0011] Furthermore, the hydrophilic hydration layer is formed by grafting two monomers into an aqueous phase. The grafting solution is a mixed aqueous solution of HEMA and NVP with a mass ratio of HEMA to NVP of 6:4 and a total mass concentration of 10% to 20% of the mixed monomers. The solvent is deionized water, and the temperature of the grafting solution is controlled below 60°C. The cable is immersed in the grafting solution for 180 to 300 seconds.

[0012] Furthermore, after extrusion, the sheath is first rapidly cooled by an annular cold air cooling device, and then enters a plasma activation device. After activation, it immediately enters a grafting water tank. After exiting the grafting water tank, the surface is cleaned with circulating water and dried by a nozzle. The extrusion, plasma activation, grafting, cleaning and drying of the sheath are carried out online continuously, and the sheath extrusion line speed is 3~5m / min.

[0013] The beneficial effects of this invention are as follows: A quaternary blend system of LLDPE, PP, low molecular weight PVDF, and EVA is used. The low molecular weight PVDF exhibits good dispersibility and excellent processing fluidity. EVA, as a compatibilizer, solves the problem of poor compatibility between PVDF and polyolefins. The selection of specialized water-resistant antioxidants and lubricants ensures long-term water immersion stability without affecting subsequent surface modification. A normal-pressure 360° annular plasma treatment machine, combined with four evenly distributed annular nozzles, achieves 360° omnidirectional activation of the cable without rotation, resulting in high activation uniformity. The HEMA and NVP are mixed in a specific ratio... The grafting sap has good water solubility, does not decompose or self-polymerize at 60℃, has a fast grafting rate, and produces a dense and stable grafted layer. The resulting hydrophilic hydration layer can effectively inhibit microbial adhesion and biofilm formation. The synergistic effect of bulk formulation modification and surface grafting modification not only ensures the mechanical strength, insulation performance, and water and aging resistance of the sheath material, but also significantly improves the antimicrobial adhesion ability, extending the service life of the cable in underwater environments by more than 50%. The entire process is compatible with conventional cable extrusion production lines, and plasma activation and grafting reactions can be carried out continuously online without the need for additional complex equipment, making it suitable for large-scale mass production. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a process flow diagram of the present invention.

[0016] Figure 2 This is a cross-sectional view of the cable in this invention.

[0017] Explanation of reference numerals in the attached drawings: 1. Sheath material granules; 2. Extruder; 3. Annular cooling device; 4. Plasma activation device; 5. Plasma jet nozzle; 6. Grafting water tank; 7. Circulating water cleaning device; 8. Air nozzle; 9. Cable core; 10. Sheath. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0019] like Figure 1 and Figure 2 As shown, sheath material granules 1 are fed into extruder 2 and heated at 200~210 °C. ° Under conditions C, the extruder extrudes and coats the outer periphery of the cable core 9 to form a sheath 10. An annular cooling device 3 is installed at the extrusion port of the extruder to rapidly cool the surface of the sheath. The cooled cable then enters a 360°C atmospheric pressure environment. °The annular cycloidal plasma activation device 4 has a cavity length of 1500 mm. Four plasma jet nozzles 5 are evenly distributed around the circumference of the cavity in a cross-shaped symmetrical ring arrangement. The plasma jet nozzles 5 are inclined at 10° towards the center of the circle. ° ~15 ° Convergence. A single supply of 99.99% high-purity argon gas is used, with a total gas flow rate of 20-24 L / min and a supply pressure of 0.25-0.35 MPa. Each nozzle has a power of 150W, with a total power of 600W. The operating frequency is 30-50 kHz, and the distance from the plasma jet nozzle 5 to the cable surface is 10 mm. The cable passes through the plasma chamber in a straight line without rotation, and the activation time is 18-30 seconds. After activation, a large number of carbon free radicals are generated on the surface of the cable sheath, with an effective lifetime of 1-3 minutes.

[0020] The plasma-activated cable is immediately placed into grafting tank 6. The grafting solution is a mixed aqueous solution of HEMA and NVP, with a HEMA to NVP mass ratio of 6:4 and a total monomer mass concentration of 10%~20%. The solvent is deionized water, and no initiators or organic solvents are added. The grafting tank is 15m long and equipped with a water circulation system and a sealed cover. Guide wheels are installed inside the tank, and the cable is completely submerged in the grafting solution. The temperature is controlled at 60°C through continuous circulation of the grafting solution. ° Below C, the effective immersion time of the cable in the grafting solution is 180~300s. The grafting reaction with HEMA or NVP is initiated by the free radicals remaining on the sheath surface, forming a hydrophilic hydration layer on the sheath surface, which can effectively inhibit microbial adhesion and biofilm formation.

[0021] After the cable exits the grafting water tank, it enters the circulating water cleaning device 7, where the cable surface is cleaned with circulating natural water to wash away excess grafting liquid. Then, the cable surface is blown away with air nozzles 8 at room temperature to remove any remaining water, resulting in the final antimicrobial adhesion underwater laying cable.

[0022] The sheath material is composed of the following components in parts by weight: 62 parts LLDPE; 12 parts PP; 10 parts PVDF with a molecular weight of 100,000 to 200,000; 10 parts EVA; 0.4 parts a mixed antioxidant composed of 3114 and PEP-36 in a 1:1 mass ratio; and 0.2 parts a mixed lubricant composed of PETS and PPA in a 2:1 mass ratio. Each component is prepared using the following steps: PVDF powder is heated to 80... ° Dry in an oven at 85°C for 4 hours, then dry LLDPE, PP, and EVA separately for 2 hours each; add all components to a high-speed mixer and heat at 85°C. ° C. Mix at 350 r / min for 18 min to obtain a mixture; feed the mixture into a twin-screw extruder with a feed section temperature of 185°C. ° C. Melting section temperature 210 ° C. Head section temperature 215 °C. The screw speed is 180 r / min, and the material is extruded and granulated to obtain sheath material particles.

[0023] Testing revealed that the sheath material of this invention has a service life in underwater environments that is more than 50% longer than that of conventional polyolefin sheaths. The surface hydrophilic hydration layer has an adhesion inhibition rate of more than 95% against Escherichia coli and Staphylococcus aureus, meeting the requirements for long-term antimicrobial adhesion of underwater cables.

Claims

1. A material for underwater cable sheathing that resists microbial adhesion, characterized in that, It is composed of the following components in parts by weight: 60-65 parts LLDPE; 10-15 parts PP; 8-12 parts PVDF; 8-12 parts EVA; 0.3-0.5 parts mixed antioxidants; and 0.1-0.3 parts mixed lubricants.

2. The antimicrobial adhesion underwater cable sheath material according to claim 1, characterized in that, The molecular weight of the PVDF is 100,000 to 200,000.

3. The antimicrobial adhesion underwater cable sheath material according to claim 1, characterized in that, The mixed antioxidant is composed of 3114 and PEP-36 in a mass ratio of 1:1, and the mixed lubricant is composed of PETS and PPA in a mass ratio of 2:

1.

4. The antimicrobial adhesion underwater cable sheath material according to claim 1, characterized in that, The composition is 62 parts LLDPE, 12 parts PP, 10 parts PVDF, 10 parts EVA, 0.4 parts mixed antioxidant, and 0.2 parts mixed lubricant.

5. A method for preparing an antimicrobial adhesion underwater cable sheath material according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Dry PVDF powder in an oven at 80℃ for 4 hours, and dry LLDPE, PP and EVA for 2 hours each; S2: Add LLDPE, PP, PVDF, EVA, mixed antioxidants, and mixed lubricants to a high-speed mixer according to the formula ratio, and mix for 15-20 minutes at 80-90℃ and 300-400r / min to obtain a mixture; S3: Feed the mixture into a twin-screw extruder, set the extrusion temperature to 200-220℃ and the screw speed to 150-200r / min, and extrude and granulate to obtain sheath material granules.

6. An antimicrobial adhesion underwater cable, comprising a cable core and a sheath covering the outer periphery of the cable core, characterized in that, The sheath is made of the sheath material described in any one of claims 1 to 4, and the surface of the sheath is grafted with a hydrophilic hydration layer containing HEMA and NVP after being activated by a 360° annular cycloidal plasma under constant pressure.

7. The antimicrobial adhesion underwater laying cable according to claim 6, characterized in that, The atmospheric pressure 360° annular rotary plasma activation uses four nozzles arranged in a cross-shaped symmetrical ring. The nozzles are tilted 10°~15° towards the center and converge. It uses 99.99% high-purity argon gas as the sole gas supply, with a total gas flow rate of 20~24L / min, a gas supply pressure of 0.25~0.35MPa, a single nozzle power of 150W, a total power of 600W, an operating frequency of 30~50kHz, a nozzle distance of 10mm from the cable surface, and an activation time of 18~30s.

8. The antimicrobial adhesion underwater laying cable according to claim 6, characterized in that, The hydrophilic hydration layer is formed by grafting two monomers into an aqueous phase. The grafting solution is a mixed aqueous solution of HEMA and NVP with a mass ratio of HEMA to NVP of 6:4 and a total mass concentration of 10% to 20% of the mixed monomers. The solvent is deionized water, and the temperature of the grafting solution is controlled below 60°C. The cable is immersed in the grafting solution for 180 to 300 seconds.

9. The antimicrobial adhesion underwater laying cable according to claim 6, characterized in that, After the sheath is extruded, it is first rapidly cooled by an annular cold air cooling device, then enters a plasma activation device, and immediately enters a grafting water tank after activation. After exiting the grafting water tank, the surface is cleaned with circulating water and then dried by a nozzle.

10. The antimicrobial adhesion underwater laying cable according to claim 6, characterized in that, The extrusion, plasma activation, grafting, cleaning, and drying of the sheath are carried out continuously online, with the sheath extrusion line speed being 3~5m / min.

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