Marine anti-fouling paint development characteristics are summarized!

Marine anti-fouling coating is a special coating, the main role is to prevent the defacement of marine life through the gradual oozing of anti-fouling agents (toxic materials) in the paint film. However, earlier anti-fouling coatings also caused secondary pollution to the marine environment while inhibiting the attachment of marine life. Therefore, the development of high-efficiency, long-lasting green marine anti-fouling coatings has become a hot research topic, and has made considerable progress

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vessels, docks and other water lines below the long-term contact with seawater, by the corrosion of seawater; The attachment of marine life makes the ship's speed drop, the hull corrosion speed accelerates, the water platform facility is destroyed, and the cooling water pipe of the power plant is blocked. Applying various marine anti-fouling coatings to them can prevent the above problems.
classification:
testing standards:
project
technical standards
anti-fouling paint model signed soaking test method
GB /T5370-2007
bottom anti-fouling paint copper ion sea Oozing rate measurement
GB/T6824-2008
boat bottom anti-fouling paint organo tin monosal solid sea seepage rate determination
GB/T6825-2008
ship defense Stain paint anti-fouling performance dynamic test method
GB/T7789-2007
anti-fouling paint anti-cathode peeling test method
GB/T7790-2008
self-polishing anti-fouling The dynamic test method of paint resistancedisc torque method
GB/T7791-87
is the main factor affecting the effect of marine anti-fouling coatings: the anti-fouling effect of
coatings is mainly manifested in both broad-spectrum and long-lasting. The ideal marine anti-fouling coating should have anti-adhesive effect on plant and animal marine attachment organisms, and have a long anti-fouling period effect. Today's marine anti-fouling coatings are generally effective for 1 to 5 years. The main factors that determine the anti-fouling effect are the following:
1) anti-fouling agent content in general, the higher the anti-fouling agent content, the longer the validity period.
2) Anti-fouling coating surface free energy low surface free energy coating is not easy to produce attachment, even if there is not secure, easy to remove or be washed away by the flowing sea water.
3) The work required for the elastic modulation of the coating to deface biological stripping is 1/2 times the surface strain (γ) and elastic mod (E) product, i.e. W ( γ. E) 1/2。 On coatings with low elastic mods, marine life can be stripped with less external force.
4) The smoother the coating surface, the less frictional resistance, the less easy it is for marine life to adhere to, so the smoothness of the coating can also extend the life and cleaning cycle of the coating.
5) The hydrophobic hydrophobic marine anti-fouling coating of the coating has obvious anti-fouling effect, and studies have been conducted to apply the surface of super-hydrophobic (surface-water contact angle is greater than 150 degrees) to marine anti-fouling.
6) The greater the difference between the coated pH coating surface sea water and the pH of normal sea water, the less likely marine life is to adhere to.
main varieties:
advanced anti-fouling coating technology mainly from Europe and the United States and Japan, mainly imitation abroad, but also relatively in the research stage. Commercial anti-fouling coatings are divided into two main categories: one is insecticide-containing anti-fouling coatings, and the other is insecticide-free anti-fouling coatings (or low-surface anti-fouling coatings, or defaced release anti-fouling coatings FRC).
1.Insecticide-containing anti-fouling coatings
most commonly used on the market when using insecticide-containing anti-fouling coatings, accounting for 90%-95% of the market. This kind of anti-fouling coating is divided into the following 3 kinds.
1) Hydrated self-polishing anti-fouling coating
mosted by physical action (dissolved by water currents) without the effect of self-smoothing coating surface. Anti-fouling coating is mainly in the uniform thinning, at the same time due to the formation of porous saponification layer and the addition of trace roughness, increase the friction during navigation, will reduce the speed of the ship, gradually increase fuel consumption.
2) Hydrolysed self-polishing anti-fouling coating
Hydrolysed self-polishing anti-fouling coating is in seawater by chemical reaction (ion exchange type and pure hydrolysed type) to achieve the purpose of coating polishing, has a good self-smoothing coating surface effect. Not only is it effective in reducing the original roughness caused by coating technology. For anti-fouling coatings that can carry out pure hydrolytic reactions (e.g. hydrolytic anti-fouling coatings based on acrylic silicane co-polymers or methyl acrylic silica co-polymers), the surface of the hull will become smoother during shipping, reducing the friction of navigation, thereby reducing fuel consumption and achieving energy saving and emission reduction.
hydrolytic self-polishing anti-fouling coatings on the market are mainly composed of the following types: zinc acrylic resin;
of the above techniques is chemical decomposition of inverted esterification of hydrolysing or ion exchange. The polymer itself is hydrophobic because it itself is bound to a functional group by an ester bond. When the polymer is immersed in seawater, the ester bond breaks, leaving a hydrochloric acid to improve the hydrophobility of the polymer.
a) acrylic copper co-polymer self-polishing anti-fouling coating (ion exchange type)
b) acrylic zinc co-adhesive self-polishing anti-fouling coating (ion exchange type)
c) silane acrylic comerlear self-polishing anti-fouling coating
3) blended self-polishing anti-fouling coating (Hybrid)
hydrated anti-fouling coating technology and provides limited self-smoothing efficacy. The main film-forming substances of the coating are hydrolytic (ion exchange) type polymer resins such as copper acrylic, zinc acrylic and other hydrophosphonic pine. The characteristics of mixed anti-fouling coatings are as follows:
a) due to the presence of pine, its solids are higher than hydrolytic (ion exchange) type anti-fouling coatings.
b) anti-fouling process is the release of insecticides through the dual action of hydrolysolation and dissolution.
c) saponified layer hydrolysing (ion exchange) type anti-fouling coating is high, up to about 60 m.
d) self-leveling performance can not be compared with high-performance hydrolytic (ion exchange) type of anti-fouling coatings
2. insecticide-free anti-fouling coatings - surface anti-fouling coatings
1) silicone low surface anti-fouling coatings
silicone refers to silicone oxane, depending on its molar quality and structure, can be divided into silicone oil, silicone resin and silicone rubber.
a) The surface of the silicone rubber as a base for anti-fouling coatings. Silicone resins are generally hydrolytically retracted by silicone monomers, which have the advantages of inorganic and inorganic materials and are very good low surface energy materials.
b) A low-surface anti-fouling coating based on silicone resin. Silicone resins are generally hydrolytically retracted by silicone monomers, which have the advantages of inorganic and inorganic materials, and are very good low surface energy materials that can be cured at relatively low temperatures.
:
a) a linear, highly elastic, fluid skeleton (producing a skeleton that is detrimental to microbial attachment).
b) has as much elastic mod as possible to help attached organisms fall off.
c) The chemical properties in the marine environment are relatively stable, there is sufficient resistance to hydrolysis, and the coating strength prevents the surface structure from being destroyed by the wash-up of seawater.
d) is thick enough to ensure that sea creatures fall off through lower-energy peeling rather than higher-energy shearing.
) coating surface achieves molecular level smoothness.
f) is free of pesticides.
disadvantages of existing silicone anti-fouling coatings:
a) coating curing depends on ambient temperature and humidity.
b) Paint fog can contaminate other ships. The cost of protection during construction is high.
c) coating is soft, undying and susceptible to mechanical damage, especially in alternating wet and dry areas.
d) Existing technologies do not prevent the growth of bacterial and algal sea creatures, which can reach a diameter of up to 1000 m. In order to reduce the surface roughness of the hull, the coating surface must be cleaned underwater on a regular basis. Failure to do so increases drag and fuel consumption. And often underwater surface cleaning, but also will cause the coating surface damage, increase roughness.
2) Organic fluorine low surface anti-fouling coating
Teflon has a very low surface energy (contact angle with water is 114 degrees), in theory should have excellent anti-fouling. However, many experts have carried out a special study on the anti-fouling of organic fluorine resin, and came up with the basic theory as follows:
a) coating is a hot-melting film, the denseness of the coating film is poor, marine microorganisms deep inside the coating film, firmly adhered to the micro-holes of the coating film.
b) resin, especially the coating surface is the vast majority of CF2 groups, compared with CF3 groups, its resistance to contamination is significantly poor.
c) When marine microorganisms come into contact with the coating surface, the surface polymer molecule is induced to rearm, which is the coating surface can be improved.
3) Silicone-fluorine resin low surface anti-fouling coatings
People in the course of research found that the surface anti-fouling coating anti-fouling performance is not good one of the big reasons: a large number of coatings are not afraid of the presence of surface energy properties of components. In order to reduce the proportion of these components in the resin, silicone, organic fluorine is used, it is worth a new type of low-surface anti-fouling coating with fluorine polysilica as the base of anti-fouling coating.
basic principle: silicon oxygen chain as the main chain, in the side chain to introduce a certain concentration of CF3 group. Because of its great surface activity, the whole large molecule not only maintains the high elasticity and high fluidity of the line polysiloxane, but also absorbs the ultra-low surface energy characteristics of the CF3 group.
To some extent, this kind of coating can improve the performance of anti-fouling coating than silicone surface, especially mechanical strength, while the adhesion to bacterial type and algae sea creatures has been reduced, but can not be completely eliminated. These coatings also need to be cleaned underwater on a regular basis.
4) Other resin low surface anti-fouling coatings
It has been reported that BRUNEL ENVIROMARINE has developed a solvent-free epoxy resin low surface anti-fouling coatings, which have also been used in cases. The characteristics are as follows:
a) The only solids are divided into 100% low surface anti-fouling coatings.
b) contains no toxins or pesticides and no harmful substances that affect your health.
c) its anti-fouling mechanism: the coating surface does not have a solvent hole conducive to the attachment of marine microorganisms in the harbor;
d) two-part, fixed mixing ratio, using conventional spray equipment.
) does not require rust-proof primers, and the entire system has a dry film thickness of 2×150 m.
f) is very limited in practice and its performance has yet to be verified.
coating method:
construction method: airless spray, brush coating, roller coating
spray hole: 0.5mm
pressure: 250kg/cm2
drying time (table dry): 7 hours (20C)
sew: minimum 12 Hours (20 degrees C) up to 3 months
paint film thickness: wet film 150 m; dry film 75 m
remaint interval: minimum 10 hours (20 degrees C); maximum 60 days
surface treatment: coating on matching primers, only the primer can be applied directly. For other construction surfaces, clean, dry, no grease, dust and other pollutants, cleaning methods can be manual, mechanical or high-pressure water flushing.
construction environment: the temperature should be higher than 15 degrees C to ensure normal construction performance. Large amounts of ventilation should be provided during construction and drying in confined spaces. Storage: 12 months (25 degrees C), stored in cool, dry conditions.
development direction:
any ship coating development should consider whether it complies with relevant laws and regulations (safety, health and environmental protection) and cost-effective, even more so ship anti-fouling coatings.
regulations on anti-fouling coatings for ships
The IMO Convention on the International Control of Harmful Anti-fouling Systems for Ships (AFS Convention) entered into force on 17 September 2008. The Convention requires that no more naked exposure to anti-fouling coatings containing organo tin be allowed at the bottom of all ships from the date of entry into force. In order to ensure the implementation of the Convention, the underbody anti-fouling coatings of the teachers must be certified as organic tin-free in the class society.
different countries often have certain limits on pesticides used in anti-fouling coatings. Because it takes a long time to develop and register a new insecticide (typically 5-10a or more) and is expensive (hundreds of dollars or more), the use of insecticides for anti-fouling coatings is extremely limited. Table 1 shows the insecticides commonly used in anti-fouling coatings. Among them, copper oxide is the most widely used anti-fouling coating insecticides, but its application and environmental protection issues have attracted many attention, some countries and organizations are conducting extensive research on it. The Ministry of Environmental Protection is also actively developing anti-fouling coatings related to environmental standards, I believe that its introduction will greatly promote and standardize the domestic anti-fouling coatings market.
High-performance anti-fouling coatings - to ensure ship speed, reduce fuel, reduce emissions
It is reported that a ship attached to marine pollutants will consume 40% more fuel than a clean hull, if all ships in the world today Sea pollutants will burn an additional 70.6 million tons of fuel, will release 210 million tons of CO2 and 5.6 million tons of SO2!
the bottom of the ship will greatly increase the roughness of the hull, thereby increasing the ship's navigational resistance, resulting in increased fuel consumption. Common underboat defacation increases the resistance to ship navigation as follows:
1) mucus defacation increases navigational resistance by up to 9%,
2) water and grass defacation increases navigational resistance by up to 19%, and
3) shell defacation increases navigational resistance by up to 33%-84%.
In today's oil and energy shortage, soaring prices and warming climate, Wuxi self-polishing, self-smooth hydrolysed anti-fouling coatings (silane acrylic co-polymer type) due to its excellent anti-fouling performance and saving navigational fuel (up to 7% of fuel savings reported) and more and more widely used.
the 1990s, non-toxic surface anti-fouling coatings (FRCs) have also been used