KR102777468B1 - Multi-functional Anti-fouling Coating and Manufacturing Method of Marine structure using the same - Google Patents

Abstract

The present invention relates to a composite antifouling coating technology and a marine structure to which a composite antifouling functional coating layer is applied. More specifically, the present invention relates to a composite functional coating technology with enhanced antifouling properties, coating retention power, etc., thereby extending the service life, and a method for manufacturing a marine structure (ship, buoy, and floating marine structure) to which the technology is applied, and particularly relates to a buoy for aquaculture among the above marine structures.

Description

{Multi-functional Anti-fouling Coating and Manufacturing Method of Marine Structure using the Same}

The present invention relates to a composite antifouling coating technology and a marine structure to which a composite antifouling functional coating layer is applied. More specifically, the present invention relates to a composite functional coating technology with enhanced antifouling properties, coating retention power, etc., thereby extending the service life, and a method for manufacturing a marine structure (ship, buoy, and floating marine structure) to which the technology is applied, and particularly relates to a buoy for aquaculture among the above marine structures.

In general, a buoy is an object that floats on the surface of the water to serve as a target or to indicate a location. It is a tool used to float various facilities necessary for aquaculture or floating facilities such as pontoon bridges on the water by utilizing buoyancy. In addition, buoys are used as one of the navigational marks installed to ensure safe navigation of ships, and are also used to indicate the presence of reefs, shallow waters, or sunken ships, and are used for a wide variety of other purposes.

The buoys most commonly used today are buoys made of Styrofoam, blow molding and injection molding using plastic materials, and tube-shaped buoys made of rubber with air injected inside.

The most commonly used Styrofoam buoys have the problem that they are easily broken by external impacts such as birds, waves, and work boats due to their fragile material. The Styrofoam buoys mentioned above have a very short service life because their structure is damaged by strong ultraviolet rays. In addition, the density of the Styrofoam material is low and the surface is rough, so foreign substances such as various shellfish can easily adhere to them, and moisture penetrates the inside of the Styrofoam, rapidly reducing buoyancy over time. In addition, broken pieces of Styrofoam float on the sea and do not easily disappear, causing serious marine pollution and coastal pollution. In other words, broken waste Styrofoam leads to the death of fish in aquaculture farms, resulting in enormous losses to the environment and fishermen's income.

In this way, styrofoam buoys are having a negative impact on the marine ecosystem and fishery resource conservation. As a temporary measure to solve this problem, products that cover styrofoam with PE material are being used. However, these products also cannot prevent seawater infiltration, and are easily corroded and damaged by sunlight and seawater, and their fragments also cause marine pollution.

Buoys produced by blow molding or injection molding using plastic materials and then assembling them have a structure in which a hollow part is formed inside to provide buoyancy. These buoys are vulnerable to impact and may be crushed or damaged due to contraction and expansion of the internal air according to seasonal temperature changes. In addition, a plug is inserted into the inlet to seal the air inlet created during blow molding and heated to compress it, but there is a problem in that the compressed part corrodes when it comes into contact with seawater. In addition, water may penetrate through the microscopic gaps created by the corrosion of the compressed part, causing the buoyancy to be lost. In addition, buoys using the plastic material have weak stress against water pressure, so they may be crushed when subjected to a large load or submerged. The buoys may be easily ruptured by a slight impact when the water temperature is low. If the buoys are even slightly damaged, water may penetrate into the buoys, causing them to lose buoyancy and immediately sink.

In the case of rubber tube buoys with air injected inside, there is a risk that the material may be deformed by strong ultraviolet rays, or the rubber tube may burst due to the expansion of the air inside or stimulation by sharp foreign substances. If the high-buoyancy tube bursts like this, it will lose buoyancy and immediately sink into the water, which can cause significant disruption to aquaculture.

Recently, a protective cover is made of synthetic resin fabric and a tubular buoy is inserted and fastened into it for use. However, even if this method is used, there is a problem that the tube body expands due to solar heat. In addition, when the rubber tube receives a large load, there is a problem that the opening or sewing part of the protective cover opens or bursts. In addition, since the protective cover of the rubber tube is made of fiber tissue on the surface, various attached organisms such as barnacles and mussels are easily attached to it, and as a result, the load of the buoy becomes heavy, and eventually, there is a problem that it loses its function as a buoy. To prevent this, toxic antifouling agents are used on the fiber covering, but this also has the problem of being harmful to the marine ecosystem environment.

In order to solve the above problem, polyurea was applied to the surface of the styrofoam buoy to prevent damage to the buoy and extend its lifespan. However, there are still problems in which aquatic organisms such as barnacles stick to the surface of the buoy and reproduce, and the weight of the buoy increases, causing the buoy to lose its function.

Korean Patent No. 1549904

The present invention has been proposed to solve the problems of the above-mentioned prior art, and provides a composite functional aquaculture buoy and marine structure in which two types of antifouling coating resins are sequentially applied to the outer surface of a floating marine structure, particularly a buoy, thereby enhancing antifouling properties, coating retention, etc., and extending the service life compared to conventional Styrofoam and plastic injection buoys.

On the one hand, the present invention

Expanded PE sheet;

A first adhesive layer laminated on the surface of the foamed polyethylene sheet and composed of a mixture of an organic silane coupling agent and carbon nanotubes (CNT);

A Fouling Release Layer laminated on the above adhesive layer and composed of a hydrophobic polymer;

A second adhesive layer laminated on the above Fouling Release Layer and composed of a mixture of an organic silane coupling agent or an amphiphilic hetero-bonding binder and carbon nanotubes (CNT); and

The present invention provides a marine structure to which a composite antifouling coating technology and a composite antifouling functional coating layer are applied, characterized in that the composite antifouling coating technology comprises a self-polishing copolymer layer composed of a hydrophilic polymer and laminated on the second adhesive layer.

The floating marine structure according to the present invention, particularly the buoy, is environmentally friendly because it does not use environmentally harmful Styrofoam material, and its service life can be improved because its antifouling properties and coating retention power are enhanced compared to existing buoy products.

In addition, the coating method according to the present invention has a fast curing speed, so it can quickly coat the surface of a buoy, and it can be applied not only to buoys but also to almost all marine facilities and products, so it has the advantage of wide versatility.

In addition, the buoy according to one embodiment of the present invention has an environmentally friendly advantage because it does not contain any volatile organic compounds (VOCs).

Figure 1 is a drawing showing a cross-section of a buoy according to one embodiment of the present invention.
FIG. 2 is a drawing showing a cross-sectional upper side of a buoy according to one embodiment of the present invention.
FIG. 3 is a drawing showing the structure of an amphiphilic polymer, which is a self-polishing copolymer layer, according to one embodiment of the present invention.
FIG. 4 is a drawing showing a spray coating method according to one embodiment of the present invention.
Figure 5 is a drawing showing the results of comparing the coating life of a buoy according to different conditions according to one embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

Marine structure (100) to which a composite antifouling coating technology and a composite antifouling functional coating layer according to one embodiment of the present invention are applied,

Expanded PE sheet (10);

A first adhesive layer (20) laminated on the surface of the foamed polyethylene sheet and composed of a mixture of an organic silane coupling agent and carbon nanotubes (CNT);

A Fouling Release Layer (30) laminated on the above adhesive layer and composed of a hydrophobic polymer;

A second adhesive layer (40) laminated on the above Fouling Release Layer and composed of a mixture of an organic silane coupling agent or an amphiphilic hetero-bonding binder and carbon nanotubes (CNT); and

It is characterized by comprising a Self-Polishing Copolymer Layer (50) laminated on the second adhesive layer and composed of a hydrophilic polymer.

In one embodiment of the present invention, the marine structure (100) means a floating marine structure such as a ship or a buoy, and the present invention is specifically described with respect to a buoy for aquaculture farms, but is not limited thereto.

In general, when applying antifouling resin to a surface, the coating life of a ship is approximately 2 years (based on 200 um application), but in the case of a ship, friction caused by the speed of travel causes the contaminants to fall off, so the coating life is longer than that of a simple structure. Therefore, when coating a buoy, the lifespan may be somewhat shorter than that of a ship, so extending the coating lifespan is an important factor in maintaining product quality.

The buoy according to the present invention is characterized in that two types of antifouling resins among antifouling coatings used for surface coating of ships and marine structures are sequentially applied to the surface of the buoy in a two-layer form.

In one embodiment of the present invention, the expanded polyethylene sheet serves as a core in the structure of the buoy of the present invention, and is preferably in the shape of a cylinder made of a low-density polyethylene foam sheet having a density of 5 to 30 g/L. The expanded polyethylene sheet is lightweight, has dimensional stability and impact resistance, and has high water-tightness, making it very useful as a buoy.

The above ‘Fouling Release Layer’ (low friction layer) preferably uses a hydrophobic resin with low surface tension and surface energy to prevent attachment of marine pollutants, and examples thereof include, but are not limited to, silicone polymers.

Specifically, it is preferable that the hydrophobic silicone polymer use a modified silicone resin containing an alkyl group such as methyl phenyl silicone, but is not limited thereto.

In addition, the coating liquid constituting the Fouling Release Layer is applied to the inside of the buoy, so it is characterized by not adding organic or inorganic biocides.

It is preferable that the above Fouling Release Layer be laminated to a thickness of 100 to 200 um.

Since the above ‘Self-Polishing Copolymer Layer’ is positioned on the outermost side of the buoy and is exposed to marine pollutants and the seawater environment, it is preferable to use a hydrophilic resin that can be hydrolyzed over time. Examples of such materials include, but are not limited to, PEG-based polyurethane (PU), acrylic polymers, etc.

Specifically, the hydrophilic PEG-based polyurethane (PU) and acrylic polymer preferably use a polyurethane-polyol copolymer, a polyurethane-polyester copolymer, a silicone-acrylate copolymer, etc., but are not limited thereto.

The above 'Self-Polishing Copolymer Layer' can be hydrolyzed over time to create a new coating layer. The 'Self-Polishing Copolymer Layer' has the characteristic of being hydrolyzed in response to alkaline seawater when exposed to a marine environment. After the surface adsorption of seaweed and marine pollutants, the superficial layer where adsorption occurred is worn away over time and a new coating layer comes into contact with seawater, and finally, when the Self-Polishing Copolymer Layer is completely peeled off, the silicone low-friction layer is exposed.

In addition, the coating liquid constituting the above ‘Self-Polishing Copolymer Layer’ is characterized by adding organic and inorganic biocides since it is applied to the outside of the buoy.

It is preferable that the above ‘Self-Polishing Copolymer Layer’ be laminated to a thickness of 100 to 200 um.

In one embodiment of the present invention, the first adhesive layer and the second adhesive layer are preferably composed of a mixture of an organic silane coupling agent and/or an amphiphilic polymer, an additive such as a crosslinking agent or an adhesive agent, and carbon nanotubes (CNT).

In the case of the base resin components constituting the Fouling Release Layer and the Self-Polishing Copolymer Layer, since the polarities are different due to hydrophobicity and hydrophilicity, it is preferable to additionally use an ‘amphiphilic polymer-based heterogeneous bonding binder (a resin that simultaneously includes a large amount of hydrophilic and hydrophobic structures within the polymer chain)’ for the second adhesive layer for bonding the two materials to improve the interfacial bonding force of the dissimilar materials.

In addition, in the case of the foamed polyethylene sheet and the Fouling Release Layer, in order to improve the adhesiveness when coating the silicone resin, it is preferable to separately use an ‘organosilane coupling agent’ similar to the role of the ‘amphiphilic heterogeneous bonding binder’ in the first adhesive layer.

As the above ‘organosilane coupling agent’, it is preferable to use isocyanate silane, vinyl silane, fluorosilane, etc., but is not limited thereto.

As the above ‘amphiphilic hetero-binding binder’ component, it is preferable to use an amphiphilic binder whose main component is an acrylic copolymer in which hydrophilic/hydrophobic monomers are cross-linked, such as Poly(ethylene glycol) monomethacrylate (PEGMA) - Ethyl methacrylate, but it is not limited thereto.

The above carbon nanotubes are used to supplement the adhesive strength of the adhesive layer coating liquid, and are preferably used in an amount of 0.1 to 2.0 wt% relative to 100 wt% of the total adhesive layer coating liquid.

It is preferable that the first adhesive layer and the second adhesive layer are laminated to a thickness of 10 to 200 um.

A method for manufacturing a buoy for aquaculture farm having a composite functional anti-fouling coating layer applied according to one embodiment of the present invention is as follows.

A step of forming a first adhesive layer by applying a first adhesive coating solution comprising a mixture of an organic silane coupling agent and carbon nanotubes (CNT) onto the surface of an expanded polyethylene (Expanded PE) sheet;

A step of forming a Fouling Release Layer by applying a low-friction coating solution composed of a hydrophobic polymer on the first adhesive layer;

A step of forming a second adhesive layer by applying a second adhesive coating solution composed of a mixture of an organic silane coupling agent or an amphiphilic hetero-bonding binder and carbon nanotubes (CNT) on the above Fouling Release Layer; and

It is characterized by comprising a step of forming a self-polishing copolymer layer by applying a self-polishing coating liquid composed of a hydrophilic polymer on the second adhesive layer.

In one embodiment of the present invention, the coating process uses a coating method using spray coating (liquid resin spraying method), and after applying the coating liquid to each layer, in consideration of the low melting point characteristics of the expanded polyethylene (Expanded PE) sheet, it is characterized in that it is cured for about 6 to 8 hours at room temperature (15 to 25°C) to prevent heat damage.

Hereinafter, the present invention will be described more specifically by examples. These examples are only for explaining the present invention, and it is obvious to those skilled in the art that the scope of the present invention is not limited to these examples.

Example: Manufacturing of buoys

Liquid silane resin of room temperature or heat-curing type, crosslinking agent, adhesive imparting agent and other additives and CNT particles of 20 nm in diameter and 10 μm in length were mixed in an appropriate ratio, and at this time, a first adhesive coating solution was prepared by stirring using a heat treatment ultrasonic disperser under the conditions of ultrasonic waves of 30 to 50 kHz, output of 10 to 30%, and processing time of 20 to 40 minutes to disperse the CNT particles.

Then, the first adhesive coating solution was sprayed onto the surface of an expanded polyethylene (Expanded PE) sheet, and cured at room temperature of 15 to 25°C for about 3 hours or at a temperature of 60 to 80°C for less than about 30 minutes to form a first adhesive layer.

Meanwhile, a low-friction coating solution was prepared by mixing and stirring organic silane and silicone resin in a room temperature environment, and then the low-friction coating solution was spray-coated on the first adhesive layer, and then cured at room temperature of 15 to 25°C for about 3 hours to form a low-friction layer.

Then, liquid silane resin, cross-linking agent, adhesion promoter, CNT particles with a diameter of 20 nm and a length of 10 um grade were mixed in an appropriate ratio using a catalyst such as platinum, and at this time, a second adhesive coating solution was prepared by stirring using a heat treatment ultrasonic disperser under the conditions of an ultrasonic wave of 30 to 50 kHz, an output of 10 to 30%, and a processing time of 20 to 40 minutes to disperse the CNT particles.

Then, a second adhesive coating solution was sprayed onto the low-friction layer, and then cured at room temperature of 15 to 25°C for about 3 hours to form a second adhesive layer.

Finally, a self-polishing coating solution was prepared using a copolymer to which a hydrophilic PEG-based polyurethane (PU) and an acrylic polymer were selectively applied as the self-polishing antifouling resin component mentioned above, and then the self-polishing coating solution was spray-coated on the second adhesive layer, and then cured at room temperature of 15 to 25° C. for about 3 hours to form a self-polishing layer, thereby preparing a buoy to which a multilayer coating solution was applied.

Comparative Example: Manufacturing of Buoys

The same method as the method for manufacturing the buoy manufactured in the above example was applied, but instead of a buoy to which both types of antifouling coating resins were applied as in the present invention, a buoy to which only one type of Fouling Release Layer or Self-Polishing Copolymer Layer was applied was manufactured.

Experimental example: Durability and water resistance evaluation

The durability and antifouling properties of the buoys manufactured in the above examples and comparative examples were compared and evaluated with those of conventionally used Styrofoam buoys, and the results are shown in Table 1 below.

division Test method According to the embodiment
buoy Fouling Release
Coated buoy Self-polishing copolymer
Coated buoy styrofoam buoy Coating appearance
_Thickness (um) - 100~200 50~100 50~100 No coating Coating durability
_Shore hardness (A) KS M ISO 868:2006 70 and above 65~75 65~75 No coating Coating durability
_Impact resistance Test analysis items related to eco-friendly buoy certification surface
Cracks, breaks,
No tearing surface
Cracks, breaks,
No tearing surface
Cracks, breaks,
No tearing surface
Cracks, breaks,
Tearing occurs Buoyancy (kgf) 28~32 30~35 30~35 30~35 Coating anti-fouling
_Marine Environment Exposure crack, break
No tearing crack, break
No tearing crack, break
No tearing crack, break
Tearing occurs Buoyancy maintenance rate
85% or more Buoyancy maintenance rate
80~85% Buoyancy maintenance rate
80~85% Buoyancy maintenance rate
75~80%

*For coating durability (shore hardness, impact resistance), the values are measured at the time of initial manufacturing before use in a seawater environment.

*The buoyancy maintenance rate is expressed as a percentage of the initial buoyancy after 2 months of use in an actual seawater environment.

With reference to Table 1 above, it was confirmed that the buoy according to the present invention is superior to prior products such as conventional styrofoam buoys and low-friction, magnetic-wear type buoys in terms of durability, coating sustainability, and buoyancy maintenance characteristics.

In addition, the results of comparing the coating life under each condition (coating thickness: 100 um ± 10) are shown in Fig. 5. While general antifouling resins have a lifespan of about 2 to 3 years, it was confirmed that the buoy according to the present invention can maintain coating performance for more than 3 years while maintaining the coating film form, and the risk of surface damage and breakage is significantly reduced.

division Buoy according to the embodiment Self-Polishing Copolymer Fouling Release Coating performance
retention 3 years 1.3~1.5 years 1.5 years Appearance changes over time Maintaining the shape of the film Maintaining the shape of the film X Maintaining the shape of the film Product protection after life FR resin after SPC resin elution
Product surface protection by coating, risk of surface damage and breakage↓ Risk of damage due to exposure of product surface after SPC resin elution Product surface by coating
Risk of damage↓

*The lifespan of the waterproof resin is approximately 2 to 3 years, and when applied in an environment with no flow, the performance is expected to be 50 to 60% of the existing performance.

As described above, specific parts of the present invention have been described in detail. It is obvious to those skilled in the art that these specific descriptions are merely preferred implementation examples and that the scope of the present invention is not limited thereto. Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above contents.

Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

100: Marine structures
10: Expanded PE sheet
20: First adhesive layer
30: Fouling Release Layer
40: Second adhesive layer
50: Self-Polishing Copolymer Layer

Claims (6)

Expanded PE sheet (10);
A first adhesive layer (20) laminated on the surface of the foamed polyethylene sheet and composed of a mixture of an organic silane coupling agent and carbon nanotubes (CNT);
A low-friction layer (Fouling Release Layer) (30) laminated on the above adhesive layer and composed of a hydrophobic polymer;
A second adhesive layer (40) laminated on the above low friction layer (Fouling Release Layer) and composed of a mixture of an organic silane coupling agent or an amphiphilic hetero-bonding binder and carbon nanotubes (CNT); and
It is characterized by comprising a self-polishing copolymer layer (50) laminated on the second adhesive layer and composed of a hydrophilic polymer;
The above low friction layer (Fouling Release Layer) and self-polishing layer (Self-Polishing Copolymer Layer) are laminated to a thickness of 100 to 200 um,
The above carbon nanotubes are used in an amount of 0.1 to 2.0 wt% relative to 100 wt% of the total coating solution constituting the first adhesive layer and the second adhesive layer.
The above foamed polyethylene sheet is a low-density polyethylene foam sheet having a density of 5 to 30 g/L,
The above low friction layer (Fouling Release Layer) does not contain any organic or inorganic biocides.
The above self-polishing copolymer layer is hydrolyzed when reacted with seawater, exposing the low-friction layer (fouling release layer), and is characterized by the addition of organic and inorganic biocides.
Marine structure (100) with composite antifouling coating technology and composite antifouling functional coating layer applied. delete delete delete delete delete

Images