Antibacterial and corrosion-resistant marine polyethylene pipe and preparation method thereof

Abstract

The present invention discloses an antibacterial and corrosion-resistant marine polyethylene pipe and a preparation method thereof. The pipe is made from the following raw materials by weight: 46.2-50.3% heat-resistant polyethylene, 20-25.4% linear low-density polyethylene, 1.1-1.5% cross-linking agent, 0.5-0.7% initiator, 0.8-1.2% catalyst, 5.5-6.9% ultra-high molecular weight polyethylene, 8-9.7% pretreated polyimide nanofibers, 6.3-7.2% nano-zirconium phosphate, and 4-5% rosin resin; the pretreated polyimide nanofibers are etched with N-methylpyrrolidone, which accounts for 6.2% of the weight of the polyimide nanofibers. The pipe prepared by the present invention has good antibacterial properties, corrosion resistance, and mechanical properties, enabling the pipe to fully meet the long-term use requirements of ships.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic pipes, in particular to an antibacterial and corrosion-resistant marine polyethylene pipe and a preparation method thereof. Background Art

[0002] Plastic pipes are commonly used on ships for transporting and discharging liquids and gases. However, existing plastic pipes lack ideal corrosion resistance and antibacterial properties. During navigation, plastic pipes below the waterline are often exposed to freshwater or seawater, which can cause corrosion and shorten their service life. Furthermore, shellfish, algae, and plankton in the water can attach to and grow in the pipes, increasing weight and drag on the hull, reducing water flow, and even causing blockages, making them difficult to clean. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an antibacterial and corrosion-resistant marine polyethylene pipe and a preparation method thereof, thereby improving the antibacterial property, corrosion resistance and mechanical properties of the pipe.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An antibacterial and corrosion-resistant marine polyethylene pipe is made of the following raw materials in percentage by weight: 46.2-50.3% of heat-resistant polyethylene, 20-25.4% of linear low-density polyethylene, 1.1-1.5% of a cross-linking agent, 0.5-0.7% of an initiator, 0.8-1.2% of a catalyst, 5.5-6.9% of ultra-high molecular weight polyethylene, 8-9.7% of pretreated polyimide nanofibers, 6.3-7.2% of nano-zirconium phosphate, and 4-5% of a rosin resin; the pretreated polyimide nanofibers are the product of etching with N-methylpyrrolidone, which accounts for 6.2% of the weight of the polyimide nanofibers.

[0006] The crosslinking agent is a mixture of epoxysilane coupling agent XR-560 and vinyltriethoxysilane in a mass ratio of 2:1.

[0007] The initiator is one or both of dicumyl peroxide and benzoyl peroxide.

[0008] The catalyst is dibutyltin dilaurate.

[0009] A method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe comprises the following steps:

[0010] (a) spraying N-methylpyrrolidone onto the surface of polyimide nanofibers under stirring, mixing uniformly, washing with water multiple times and filtering to remove the N-methylpyrrolidone, and then drying the polyimide nanofibers to obtain pretreated polyimide nanofibers;

[0011] (b) pretreated polyimide nanofibers, heat-resistant polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, nano zirconium phosphate, and rosin resin are uniformly mixed to obtain a premix; the premix, a cross-linking agent, an initiator, and a catalyst are input into a screw extruder for melt extrusion, and the premix is ​​sized by vacuum and cooled in a water tank for shaping to obtain an antibacterial and corrosion-resistant marine polyethylene pipe.

[0012] In step (a), the mixing and stirring time is 15 minutes.

[0013] In step (a), the drying temperature is 98-105°C.

[0014] In step (b), during melt extrusion, the temperatures of zones 1 to 5 of the extruder are 170-175°C, 175-180°C, 180-190°C, 190-195°C, and 195-200°C, respectively, and the die temperature is 190-195°C.

[0015] In step (b), the vacuum sizing pressure is 0.9-1.2 MPa.

[0016] In step (b), the temperature of the cooling water in the water tank during cooling and shaping is 15-20°C.

[0017] The beneficial effects of the present invention are: the surface of the polyimide nanofiber is etched by a solvent, so that the surface of the polyimide nanofiber becomes rough, so that part of the polyethylene can self-crosslink at the rough surface of the polyimide nanofiber, so as to improve the bonding strength between the polyimide nanofiber and the polyethylene substrate, thereby improving the strength, corrosion resistance and antibacterial properties of the pipeline. At the same time, by compounding ultra-high molecular weight polyethylene and nano-zirconium phosphate, the corrosion resistance and antibacterial properties are further improved, so that the pipeline can fully meet the long-term use requirements of ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of the present invention when the improved water tank cooling shaping mechanism is used for cooling;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0020] Figure 3 for Figure 1 Partial cross-section along the middle BB direction;

[0021] Figure 4 for Figure 3 Partial cross-section along the CC direction.

[0022] In the figure: water tank 1, thrust member 2, mounting box 3, inner guide groove member 31, outer guide groove member 32, drive assembly 4, inner cylinder 41, bevel gear A 411, inner convex ring 412, bevel gear C 413, rotating shaft 414, motor 415, outer cylinder 42, slide groove 421, bevel gear B 422, outer convex ring 423, inner guide member 43, groove 431, side hole 432, outer guide member 44, inner connecting member 45, ball guide portion 451, guide column 452, outer connecting member 46, inner push rod 47, outer push rod 48, connecting rod portion 481, oblique rod portion 482, guide plate 49, guide groove 491, cylinder 492, spray mechanism 5, pipeline to be cooled 6. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0024] An antibacterial and corrosion-resistant marine polyethylene pipe is made from the following raw materials in percentage by weight: 46.2-50.3% heat-resistant polyethylene, 20-25.4% linear low-density polyethylene, 1.1-1.5% crosslinker, 0.5-0.7% initiator, 0.8-1.2% catalyst, 5.5-6.9% ultra-high molecular weight polyethylene, 8-9.7% pretreated polyimide nanofibers, 6.3-7.2% nano-zirconium phosphate, and 4-5% rosin resin. The pretreated polyimide nanofibers are etched with N-methylpyrrolidone, which accounts for 6.2% of the polyimide nanofiber weight. The crosslinker is a mixture of epoxysilane coupling agent XR-560 and vinyltriethoxysilane in a mass ratio of 2:1. The initiator is one or both of dicumyl peroxide and benzoyl peroxide. The catalyst is dibutyltin dilaurate. The linear low-density polyethylene has a density of 0.921 g / cm 3 .

[0025] The preparation method of the antibacterial and corrosion-resistant marine polyethylene pipe comprises the following steps:

[0026] (a) spraying N-methylpyrrolidone onto the surface of polyimide nanofibers under stirring, mixing uniformly (mixing and stirring time is 15 minutes), washing with water multiple times and filtering to remove the N-methylpyrrolidone, and then drying the polyimide nanofibers (drying temperature is 98-105° C.) to obtain pretreated polyimide nanofibers;

[0027] (b) pretreated polyimide nanofibers, heat-resistant polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, nano zirconium phosphate, and rosin resin are uniformly mixed to obtain a premix; the premix, crosslinking agent, initiator, and catalyst are input into a screw extruder for melt extrusion (during melt extrusion, the temperatures of zones 1 to 5 of the extruder are 170-175° C., 175-180° C., 180-190° C., 190-195° C., and 195-200° C., respectively, and the die head temperature is 190-195° C.), and vacuum sizing (the vacuum sizing pressure is 0.9-1.2 MPa) and water tank cooling and shaping (the cooling water temperature during water tank cooling and shaping is 15-20° C.) to obtain an antibacterial and corrosion-resistant marine polyethylene pipe.

[0028] Antibacterial and corrosion-resistant marine polyethylene pipes were manufactured according to the above method and the formula and process parameters shown in Table 1 as Examples 1-6.

[0029] Table 1

[0030]

[0031]

[0032] Comparative Example 1

[0033] An antibacterial and corrosion-resistant marine polyethylene pipe was manufactured according to the method of Example 1, except that the polyimide nanofibers were not pretreated with N-methylpyrrolidone.

[0034] Comparative Example 2

[0035] Antibacterial and corrosion-resistant marine polyethylene pipes were manufactured according to the method of Example 1, except that ultra-high molecular weight polyethylene was not added.

[0036] Comparative Example 3

[0037] Antibacterial and corrosion-resistant marine polyethylene pipes were manufactured according to the method of Example 1, except that no or no nano zirconium phosphate was added.

[0038] The performance tests were conducted on the antibacterial and corrosion-resistant marine polyethylene pipes manufactured in Examples 1-6 and Comparative Examples 1-3 (the pipe specifications were all DN25). The results are shown in Table 2.

[0039] Table 2

[0040]

[0041]

[0042] The pipes manufactured in Examples 1-6 all had an antibacterial rate of over 98.5% against Escherichia coli, an antibacterial rate of over 99.1% against Staphylococcus aureus, an antibacterial rate of over 96.7% against Listeria, an antibacterial rate of over 96.5% against Erysipelothioneins, an antibacterial rate of over 97.2% against Mycobacterium tuberculosis, and an antibacterial rate of over 96.8% against Pseudomonas fluorescens. The pipes manufactured in Comparative Examples 1-3 all had an antibacterial rate of over 98.5% against Escherichia coli, an antibacterial rate of over 99.1% against Staphylococcus aureus, an antibacterial rate of over 96.7% against Listeria, an antibacterial rate of over 96.5% against Erysipelothioneins, an antibacterial rate of over 97.2% against Mycobacterium tuberculosis, and an antibacterial rate of over 96.8% against Pseudomonas fluorescens.

[0043] After vacuum sizing, pipes are not completely cooled and must be cooled in cooling water tanks. However, in existing technologies, cooling pipes in cooling water tanks is usually done in a circumferential spraying manner, with the cooling water flowing downward or upward. Downward flow can impact the upper portion of the pipe, which has not yet been completely cooled and shaped, while upward flow can impact the lower portion of the pipe, which has not yet been completely cooled and shaped. Due to gravity and the impact of the cooling water, pipes that have not yet been completely cooled and shaped are prone to having thinner walls at the top and thicker walls at the bottom, or thinner walls at the bottom and thicker walls at the top, making it difficult to ensure production quality.

[0044] Therefore, the present invention has improved the water tank cooling shaping mechanism, such as Figure 1-4 As shown, the improved water tank cooling shaping mechanism includes a water tank 1 for the cooling pipe 6 to pass through horizontally, two push members 2, installation boxes 3 respectively arranged on both sides of the water tank 1, and two sets of drive components 4 arranged opposite to each other and both arranged in the installation boxes 3; each set of the drive components 4 includes a circular inner cylinder 41, a circular outer cylinder 42, an upright inner guide 43 fixed on the inner wall of the lower part of the inner cylinder 41, an upright outer guide 44 fixed on the inner wall of the lower part of the outer cylinder 42, an inner connecting member 45 extending into the inner guide 43 and being able to extend or push in radially, and an outer connecting member 46 extending into the outer guide 44 and being able to extend or push in radially, the inner cylinder 41 and the outer cylinder 42 are distributed inside and outside, and the inner cylinder 41 and the outer cylinder 4 are arranged inside and outside. 2 is connected in reverse circumferential rotation, and the inner guide member 43 and the outer guide member 44 are distributed on the inner and outer sides and the front and back sides; the two push members 2 are set as one long and one short, and both ends of the two push members 2 pass through the water tank 1, and the two ends of the short push member 2 are respectively connected to the inner connecting members 45 on both sides, and the two ends of the long push member 2 are respectively connected to the outer connecting members 46 on both sides. Each group of the driving components 4 drives the two push members 2 to reciprocate within a range smaller than a semicircular arc, and the movement directions of the two push members 2 remain opposite; when the push member 2 moves from bottom to top, the top of the push member 2 slides and abuts the outer wall of the cooling pipe 9, and when the push member 2 moves from top to bottom, the top of the push member 2 is spaced from the outer wall of the pipe 9.

[0045] The outer end of the inner cylinder 41 extends into the wall of the outer cylinder 42 and the inner cylinder 41 and the outer cylinder 42 are circumferentially connected and slidingly connected. An annular groove 421 is provided in the outer cylinder 42 for the inner cylinder 41 to slide and fit into.

[0046] Each set of the drive assembly 4 further includes an A bevel gear 411 fixedly mounted on the inner cylinder 41, a B bevel gear 422 fixedly mounted on the outer cylinder 42, and a plurality of C bevel gears 413 meshing with the A bevel gear 411 and the B bevel gear 422. The plurality of C bevel gears 413 are evenly distributed around the circumference, and each C bevel gear 413 is rotatably mounted to the mounting box 3 via a rotating shaft 414, one of which is driven by a motor 415 for forward and reverse rotation. Through the above arrangement, the motor 415 drives the C bevel gear 413 to rotate, thereby driving the A bevel gear 411, the B bevel gear 422, and the other C bevel gears 413 to rotate, thereby causing the inner cylinder 41 and the outer cylinder 42 to rotate in opposite directions, and then driving the two push members 2 to rotate in opposite directions via the inner guide member 43 and the outer guide member 44. In order to further ensure the rotation stability of the inner cylinder 41 and the outer cylinder 42, a circular inner guide groove part 31 is fixedly installed on the inner side of the installation box 3, and the inner end of the inner cylinder 41 has a raised annular outer wall to form an inner convex ring 412, which is embedded in the inner guide groove part 31 and is circumferentially slidably connected to the inner guide groove part 31; a circular outer guide groove part 32 is fixedly installed on the outer side of the installation box 3, and the outer end of the outer cylinder 42 has a raised annular outer wall to form an outer convex ring 423, which is embedded in the outer guide groove part 32 and is circumferentially slidably connected to the outer guide groove part 32.

[0047] Each group of the drive components 4 also includes an inner push rod 47, an outer push rod 48 and an annular guide plate 49 fixed in the installation box 3. The inner push rod 47 and the outer push rod 48 both include a connecting rod portion 481 and an inclined rod portion 482 formed by the outer end of the connecting rod portion 481 extending inward and downward. The connecting rod portion 481 of the inner push rod 47 is longer than the connecting rod portion 481 of the outer push rod 48. The inclined rod portion 482 of the inner push rod 47 passes through the inner guide member 43 and the inner connecting member 45, and the inclined rod portion 482 of the outer push rod 48 passes through the outer guide member 44 and the outer connecting member 46. The guide plate 49 is driven to move inside and outside by multiple cylinders 492. An annular guide groove 491 is provided on the guide plate 49, and the longitudinal section of the annular guide groove 491 is a horizontal convex shape. The outer ends of the connecting rod portion 481 of the inner push rod 47 and the outer ends of the connecting rod portion 481 of the outer push rod 48 are slidably embedded in the guide groove 491 respectively. The connecting rod portion 481 is in a transverse T-shape, and the guide groove 491 with a transverse convex shape in the longitudinal section cooperates with the transverse T-shaped connecting rod portion 481 to ensure the circumferential rotation of the inner push rod 47 and the outer push rod 48, while ensuring that the movement of the guide plate 49 can drive the inner and outer sides of the inner push rod 47 and the outer push rod 48 to move.

[0048] Specifically, the inner connecting member 45 and the outer connecting member 46 both include a spherical ball guide portion 451 and a guide column 452 connected to the ball guide portion 451, and the inner guide member 43 and the outer guide member 44 both include a groove 431 for the guide column 452 to slide into, and a pair of side holes 432 respectively located on the inner and outer sides of the groove 431. The pair of side holes 432 are opened on the side wall of the inner guide member 43 and the side wall of the outer guide member 44. The side hole 432 located on the inner side of the pair of side holes 432 is set at a position lower than the side hole 432 located on the outer side. The connecting rod portion 481 of the inner push rod 47 passes through the pair of side holes 432 of the inner guide member 43 and the guide column 452 of the inner connecting member 45, and the connecting rod portion 481 of the outer push rod 48 passes through the pair of side holes 432 of the outer guide member 44 and the guide column 452 of the outer connecting member 46. When the inclined rod portion 482 abuts against the upper ends of a pair of side holes 432, the inner connecting member 45 and the outer connecting member 46 are pushed out to the ball guide portion 451 to abut against the outer wall of the pipe to be cooled 6. When the inclined rod portion 482 abuts against the lower ends of a pair of side holes 432, the inner connecting member 45 and the outer connecting member 46 are pushed in so that the ball guide portion 451 is spaced apart from the outer wall of the pipe to be cooled 6.

[0049] A circumferentially distributed spray mechanism 5 is provided in the water tank 1 , and the spray mechanism 5 performs circumferential spraying on the cooling pipe 6 . The installation structure of the spray mechanism 5 belongs to the prior art and will not be described in detail.

[0050] Initially, the outer guide member 44, the inner connecting member 45, the outer connecting member 46, the inner push rod 47, and the push member 2 are all located at the bottom, and the guide plates 49 on both sides are pushed to move inward (close to the end of the water tank 1), so that the inner push rod 47 and the outer push rod 48 move inward until the inclined rod portion 482 abuts against the upper ends of a pair of side holes 432, thereby pushing the inner connecting member 45 and the outer connecting member 46 upward, and the two push members 2 are also pushed upward. When the improved water tank cooling shaping mechanism is used for cooling shaping, the cooling pipe 6 passes through the installation box 3, the inner cavity of the guide plate 49, the inner cavity of the inner tube 41, the inner cavity of the outer tube 42, and the water tank 1, and the circumferential spray is turned on. The ball guide parts 451 of the two inner connecting parts 45, the ball guide parts 451 of the two outer connecting parts 46, and the two push members 2 all abut against the outer wall of the pipe to be cooled 6 (from the side perpendicular to the axial direction, the inner connecting parts 45, the outer connecting parts 46 and the central axis of the inner tube 41 are distributed in a fan shape, as shown in FIG. Figure 3 As shown), the inner cylinder 41 and the outer cylinder 42 are driven to rotate toward each other, so that the push member 2 ( Figure 3 The push member 2 on the right side moves upward counterclockwise, and the push member 2 on the rear side ( Figure 3The push member 2 on the right side moves upward clockwise. During the movement, the push member 2 always slides and abuts against the outer wall of the pipe to be cooled 6, thereby playing the role of pushing the outer wall of the pipe to be cooled 6 upward to offset the influence of gravity and the downward flow of water on the pipe to be cooled 6, and greatly reducing the occurrence of the phenomenon that the pipe wall is thick at the top and thin at the bottom. When the two push members 2 move from bottom to top to the upper part (at a position symmetrical to the upper and lower parts of the lower part at the beginning), the guide plates 49 on both sides are pushed to translate outward (away from the end of the water tank 1), so that the inner push rod 47 and the outer push rod 48 translate outward, thereby pushing the inner connecting member 45 and the outer connecting member 46 to be pushed downward, and the two push members 2 are also taken away from the cooling pipe 6 to be cooled. At the same time, the inner cylinder 41 and the outer cylinder 42 are driven to rotate in opposite directions, so that the push member 2 on the front side moves downward clockwise and the push member 2 on the rear side moves downward counterclockwise. During the movement, the push member 2 does not contact the outer wall of the pipe to be cooled 6 at all times, thereby preventing the push member 2 from pushing the outer wall of the pipe to be cooled 6 downward; by driving the reciprocating motion of the two push members 2, the push member 2 pushes the outer wall of the pipe to be cooled 6 from bottom to top.

[0051] Antibacterial and corrosion-resistant marine polyethylene pipes were manufactured using the improved water tank cooling and shaping mechanism according to the methods of Examples 1-3 (Examples 1-6 all used a conventional water tank cooling and shaping mechanism for spray cooling), designated as Examples 7-9. Comparing the properties of the pipes manufactured in Examples 1-3 with those manufactured in Examples 7-9, it was found that the tensile strength of the pipes manufactured in Examples 7-9 increased by 7.4%, 7.8%, and 7.6%, respectively, and the impact strength increased by 8.2%, 8.3%, and 8.1%, respectively. After batch production, it was found that the probability of uneven wall thickness when manufactured in Examples 7-9 was 6.5%, 6.7%, and 6.6% lower than when manufactured in Examples 1-3, respectively.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An antibacterial and corrosion-resistant marine polyethylene pipe, characterized in that: The invention is made of the following raw materials in percentage by weight: 46.2-50.3% heat-resistant polyethylene, 20-25.4% linear low-density polyethylene, 1.1-1.5% cross-linking agent, 0.5-0.7% initiator, 0.8-1.2% catalyst, 5.5-6.9% ultra-high molecular weight polyethylene, 8-9.7% pretreated polyimide nanofibers, 6.3-7.2% nano-zirconium phosphate, and 4-5% rosin resin; the pretreated polyimide nanofibers are the product of etching with N-methylpyrrolidone accounting for 6.2% of the weight of the polyimide nanofibers; The crosslinking agent is a mixture of epoxysilane coupling agent XR-560 and vinyltriethoxysilane in a mass ratio of 2:1; and the initiator is benzoyl peroxide.

2. The antibacterial and corrosion-resistant marine polyethylene pipe according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate.

3. A method for preparing the antibacterial and corrosion-resistant marine polyethylene pipe according to any one of claims 1 to 2, characterized in that: The following steps are involved: (a) spraying N-methylpyrrolidone onto the surface of polyimide nanofibers under stirring, mixing uniformly, washing with water multiple times, and filtering to remove the N-methylpyrrolidone, and then drying the polyimide nanofibers to obtain pretreated polyimide nanofibers; (b) Pretreated polyimide nanofibers, heat-resistant polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, nano-zirconium phosphate, and rosin resin are uniformly mixed to obtain a premix; the premix, a cross-linking agent, an initiator, and a catalyst are input into a screw extruder for melt extrusion, and the premix is ​​subjected to vacuum sizing and water tank cooling and shaping to obtain an antibacterial and corrosion-resistant marine polyethylene pipe.

4. The method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe according to claim 3, characterized in that: In step (a), the mixing and stirring time is 15 minutes.

5. The method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe according to claim 3, characterized in that: In step (a), the drying temperature is 98-105°C.

6. The method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe according to claim 3, characterized in that: In step (b), during melt extrusion, the temperatures of zones 1 to 5 of the extruder are 170-175°C, 175-180°C, 180-190°C, 190-195°C, and 195-200°C, respectively, and the die temperature is 190-195°C.

7. The method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe according to claim 3, characterized in that: In step (b), the vacuum sizing pressure is 0.9-1.2 MPa.

8. The method for preparing an antibacterial and corrosion-resistant marine polyethylene pipe according to claim 3, characterized in that: In step (b), the temperature of the cooling water in the water tank during cooling and shaping is 15-20°C.

Images