KR830002687B1 - Marine antifouling paint composition - Google Patents

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Description

Marine antifouling paint composition

The present invention relates to a marine antifouling coating composition containing a micro-encapsulated film of the pesticidal substances do not mix with water. Prior to the present invention, numerous marine antifouling paints have been developed by mixing effective antifouling agents with suitable marine paint components. These paints have been used on the surface of submerged ships to prevent marine life from adhering to and growing on them. Marine antifouling coating compositions of this type are described as examples in US Pat. Nos. 2,970, 923 and 4,139, 515, 4,143,015. Nos. 2,970, 923 are varnishes, pigments and triphenyltin chloride as antifouling agents. Marine antifouling coating composition containing a has been published. Triphenyltin chloride is equally dispersed in the paint developer. U.S. Patent No. 4,139,515 also discloses a marine antifouling paint, which is an emulsion of an oil film-forming emulsion interpolymer containing triorganotinsalt of an olefinically unsaturated carboxylic acid, and reacts with seawater to make it water-soluble. It consists of a pigment containing a poorly soluble metal which can form a metal compound. When the paint dissolves, triorganic ions are released into the seawater to act as pesticides. U.S. Patent No. 4,143,015 discloses an antifouling paint containing poisons dispersed in an aqueous solution of vinyl acetate resin. Cuprous oxide and organotin compounds are used as suitable poisons. In all of these technologies, anti-fouling paints for ships and their coatings were used on the surface of ships to be protected from the growth of bottom-mounted organisms. As the coating dissolves or wears off, pesticides that act as insecticides are leached from the surface of the ship and act at a lethal concentration for marine life. After a period of time it is no longer effective because the concentration of the antifouling agent leaching from the surface falls below the lethal concentration level. This can happen when the paint has run out, additional contaminants dispersed in the paint do not leach from the bottom surface, or are not in contact with marine life. Therefore, in the prior art, it has been one of the objectives to manufacture marine antifouling paints in which the leaching rate of insecticides is controlled in order to control the dissolution rate of the paint and to extend the useful life of the paint. The economic importance of extending the effectiveness of antifouling agents is summarized in a recent report issued by the US Navy. (Ad Hoc Fouling, Biodeterioration Committee, Survey Report: Navy Biological Fouling and Deterioration, Report NUC TP 456, March 1975).

The report said, "The current anti-fouling coatings used for ships are valid for up to 18 months, and the cruising distance of large and small ships is reduced by increasing obstacles that contaminate the ship, and fuel consumption is also partially contaminated. After seven months of sinking it is significantly reduced. ” This suggests that the US Navy's indirect costs to prevent bottom pollution are $ 80 million annually in addition to fuel use. In the Mediterranean, engine cooling holes can be completely blocked after 1-2 months of flooding, and the rapid contamination of the ship's power plant can cause shutdowns. The report notes that the primary cause of high dry-cocking is scraping contaminants and replenishing antifouling coatings. This would cost more than $ 15 million annually. In addition, because of the deterioration of ship peeling due to contamination, the US Navy spends $ 20 million a year to replace biologically degraded and structurally weaker fills. The most important biological contaminant in tropical waters is the barnacle species (Janes GA: Problems in Testing Long Term Antifoulants, in: Proceedings of the 1976 Controlled Release Pesticicide Symposium, Cardrelli NF, Editor, Engineering and Science Divsion, Community and Technical College, The University of Akron, Ohio.

Other contaminants that are harmful to the surface of the ship include moss, cysts, fungi, hydro- worms, oysters, earthworms and seaweeds. As described above, the present invention relates to a marine antifouling coating composition containing microencapsulated pesticides. Classical methods for encapsulating oil are described in Vungenwern de Jay, Claude Science, Vol. 2, pp. 339-341 (H.R. Kruty ed. 1949) and US Pat. Nos. 2,730,456 and 2,730,457. According to the patent, the Avavia rubber is first dissolved in water and the oil to be encapsulated is put in an arabic rubber solution until the oil droplets are about 2-5 microns in diameter. Then mix the gelatine aqueous solution with this emulsion. All these steps are done at a temperature of about 50 degrees Celsius. The gelatin-Arabic colloid is coacervate by cold water or by lowering the pH by adding acid. Finally, formaldehyde is added thereto to cure the film. Methods of making additional composite coacervates for encapsulating liquids exhibiting the state of the art are described in US Pat. Nos. 2,800,457 and 3,956,172 and Reissue Patent 28,779. Each of these prior art methods is similar to the classical method which can be coacervated by adding water or lowering the pH value as described above.

As an important component of the composition of the present invention, the microencapsulated body can be prepared by encapsulating a liquid or a solid chemical product which is not mixed with water, and the chemical product is gelatin type A (which shows an isoelectric point of PH 7-9) and The film is coated with a polymer film of composite coacervate made of gum arabic. The method of microencapsulating these liquids or chemicals comprises preparing a colloidal solution containing gelatin type A, gum arabic and water at high temperature, and then containing the chemical and water to be microencapsulated. In the case of liquids, emulsions or slurries containing powdered inorganic substances are prepared. The emulsion or slurry of the by-product chemicals is then poured into the colloidal solution of gelatin and gum arabic with slow stirring and slowly cooled to room temperature. Chemicals dispersed during cooling are coated with composite coacervates. After cooling the mixture further at lower temperatures, the precipitated microencapsule bodies are washed and resuspended in water. In the next step, cold glutaraldehyde is added thereto to crosslink and stabilize the walls of the microencapsulation bodies, and then the microfilms are washed and dried. The antifouling paint for ships having an extended life can be produced by adding a dry microencapsulated body containing the antifouling insecticide as prepared above to the marine paint. These microencapsulations extend the antifouling effect by slowly releasing the antifouling agent from the surface of the paint. Microencapsules of other fungicides or pesticide chemicals that are not mixed with water can be prepared by the present method and then added to the coating composition for the purpose of requiring a constant release rate of these chemicals.

The microencapsulated body as an important component of the composition of the present invention can be prepared by encapsulating a liquid or solid chemical product with a polymer film of a composite coacervate made of gelatin type A and gum arabic. First, gelatin is mixed by continuously stirring about 0.9-1.1 parts of gelatin type A by weight, about 0.9-1.1 parts by weight of gum arabic and about 45-47 parts by weight of water at a temperature of about 55-60 degrees Celsius. And a colloidal solution of gum arabic is prepared. Whenever water is used in this process, the water is preferably distilled water. If the chemical to be microencapsulated is a liquid that is not mixed with water, the emulsion of the chemical should contain about 3.9-4.1 parts by volume of chemical, about 7.6-7.9 parts by volume of water, and a suitable emulsifier by weight. It is prepared by mixing 0.1-10%. The emulsifier is a finely divided inorganic material based on the weight of the water and the liquid that is not mixed with water. Suitable finely chopped inorganic materials are silica such as Cab-O-Sil or bentonite. Depending on the degree of ease of emulsification of chemicals that are not mixed with water, the finely divided inorganic material should be mixed with the liquid that is not mixed with water first, or with water before mixing with another. By using these finely cut materials, the release rate is controlled and microencapsules of the same size are produced. The homogenizer is then used to disperse the aqueous chemically aqueous solution until the dispersed droplets of the chemical to be microencapsulated are of the desired size. The mixture is kept at high temperature during emulsification.

If the chemical to be encapsulated is a finely chopped solid that does not mix with water, the slurry of the chemical is about 0.9-1.1 parts by weight of the chemical, about 4-5 parts by weight of water, and if necessary, Tween 20 It is prepared by mixing about 0.01 parts by weight of the same dispersant and then slowly stirring it, which does not require an emulsifier. Emulsions or slurries containing a colloidal solution of gelatin type A and gum arabic or chemicals to be encapsulated are prepared at a temperature of at least about 50 degrees Celsius, preferably at a temperature of about 55-60 degrees Celsius. Pour into the colloidal solution and continue to stir at a pH of about 4.5 while slowly cooling to room temperature. During cooling, droplets or particles of chemicals are encapsulated by coalescing complex coacervates. The ratio of the emulsion or slurry to the colloidal solution can be varied widely to suit the wall thickness of the polymer membrane of the composite collosebate. These ratios, which are suitable for preparing microencapsulated bodies for marine antifouling paints, have been found to be 1: 4 in volume of emulsion or slurry: colloidal solution. If liquids or finely divided solid chemicals are hydrolyzed to produce a suitable acidity of pH 4.5, encapsulation proceeds without the addition of acid. Chemicals that change their pH include tributyl tin chloride. However, when using solids that are non-sintering in water, such as tributyl tin fluoride, the gelatin-arabic rubber clade should be slowly acidified to pH4.5 by adding a suitable acid, ie, hydrochloric acid, to the coacervate formed at lower temperatures. The mixture is then cooled to encapsulate droplets or particles of chemicals that are not mixed in water with the combined composite coacervates, and then lower the mixture temperature to about 4-10 degrees Celsius. Excess unused to encapsulate chemicals that do not mix in water by washing the microencapsulated precipitated in the next step several times in cold distilled water, which is about five times its volume, while maintaining a temperature of about 4 to 10 degrees Celsius. Remove complex coacervate. Finally, after washing, the precipitated microencapsulated bodies are resuspended in cold distilled water having a volume of at least the same volume as that of the composite coacervate. A cold solution of a fixative, such as glutaraldehyde, formaldehyde, or tannic acid, or a single-, multi-crosslinking binder, is then added to a volume of about 1-2% concentrate to crosslink and stabilize the walls of the cold microcapsule. During the fixing step, the mixture is stirred for at least about 15-30 minutes at a temperature of about 4 degrees Celsius-10 degrees Celsius and then left at this temperature for at least 4 hours. The wet microencapsulations are washed, separated by precipitation and dried by lyophilization. This method is particularly advantageous for microencapsulating pesticide-retaining antifouling agents, and finds that liquid tributyl tin chloride, which does not mix with water, and solid tributyl tin fluoride, which does not mix with water, may be particularly acceptable as an antifouling agent for the bottom. It was. Microencapsulations containing antifouling agents may be added to marine paints which do not contain any other antifouling agents or to specially formulated marine anticorrosives containing antifouling agents. High quality bottom coatings, such as US Navy type 1,020 A basic paints, which are widely used commercially, can be used as marine coatings which constitute the composition of the present invention. Microencapsulations of various types of antifouling agents can be applied to the paint when trying to prevent the marine contaminants from combining to form a special combination. Because the antifouling agent is microencapsulated, marine paints can be saturated at higher concentrations than when pesticides were formulated directly into the paint as a liquid.

The microencapsulation material of the antifouling agent constituting the composition of the present invention may be mixed with the basic paint colorant such that the weight of the microencapsulation material in the entire coating composition is up to about 50%. When the microencapsulation material of the antifouling agent prepared by this process is applied to a conventional marine coating agent such as vinyl rosin type 3723-21 (M & T Chemicals Inc), the antifouling agent is slowly released from the surface of the paint and contaminated on the bottom surface. It has been found that the effectiveness of preventing the growth of the sieve is prolonged dramatically. The concentrations of pesticides submerged by this controlled release rate of contamination and the painted test panels were maintained for over 20 months with 100% contamination. The microencapsulated product of the chemical constituting the composition of the present invention can be obtained by encapsulating a chemical that sterilizes or kills insecticides. It can be added to the usual paint containing. The present invention may be more fully understood by reference to the following examples, which are related to coating compositions containing microencapsules within the scope of the present invention, and do not limit the present invention.

Example 1

Tributyl tin chloride, a liquid antifouling agent, is microencapsulated into a thin polymer film of coacetate made of gelatin and gum arabic, and then stabilized and dried. First, 10 g of gelatin type A (USP), 10 g of gum arabic (USP), and 460 ml of distilled water were mixed and heated to 55 degrees Celsius while stirring was continued for at least 1 hour. In another vessel, 75 ml of distilled water containing 0.25 g of Cab-O-Sil was added thereto and 40 ml of tributyl tin chloride (M & T Chemical Co) was added thereto. Cab-O-Sil is the smallest sized sonication of a very pure mass of inorganic matter. Then use a Viltis Co. or Polyman (Brinkman Instruments) homogenizer to disperse tributyl tin chloride in an aqueous solution until the diameter of the dispersed oil droplets is appropriate (10-30 μm) during emulsification. This mixture was maintained at 55-60 degrees. At about 55 degrees Celsius, about 115 ml of water-dispersed tributyl tin chloride was poured into about 460 ml of a colloidal solution of gelatin and gum arabic and cooled slowly to room temperature. During cooling, tribudil tin chloride is coated with a composite coacervate. Lower the temperature of the mixture further and leave overnight at a temperature of 4-10 degrees Celsius. Precipitated microencapsule bodies were washed four times in cold distilled water about five times their volume. After washing, the microencapsulated precipitates were suspended in cold distilled water as much as the initial volume where the composite coacervate was produced. 17 ml of cold glutaraldehyde 50% solution was added to 1.5% of the final concentrate to crosslink and stabilize the walls of the encapsulant. The mixture was stirred for 15 minutes at a temperature of 4 degrees Celsius and then left as it was without stirring at 4 degrees Celsius. Microcapsules having a diameter of 10-30 μm were washed with tap water at room temperature to remove the fixed solution and dried by lyophilization. The dried microencapsulations are then prepared for application to a suitable bottom paint or are sealed and stored at room temperature for later use.

Example 2

The preparation method of Example 1 can be modified by encapsulating tributyltin chloride with a thick polymer film of coacervate made of gelatin and gum arabic. Repeat the process of Example 1 using finely cut (5-50 μm) bentonite (USP) instead of Cab-O-Sil, but instead of water used in Example 1, mix 40 ml of butyltin chloride and 0.25 g of bentonite, This formed a dispersed emulsion. Before the mixture was emulsified, it was mixed with 75 ml of distilled water and added to a colloidal solution of gelatin and gum arabic. The rest of the procedure was done as described in Example 1. The diameter of the obtained microcoat body was about 50-100 micrometers. Thick walled microencapsules release the anticontaminant at the same slow rate as smaller encapsulations containing the same contaminant.

Example 3-16

In the first group, microencapsule bodies of tributyltin chloride having a diameter of 50-100 μm were prepared by Example 2 using finely cut bentonite (USP). In a second group, microencapsule bodies of tributyltin chloride having a diameter of 10-30 μm were prepared by homogenizing at a higher speed. Using a thin Cab-O-Sil according to the procedure of Example 1 to prepare a third group of microcapsules of 10-30 μm diameter tributyltin chloride. The fourth group was prepared by emulsifying at high speed as the diameter of the microencapsulated body was 1-10 μm. On average, the microencapsulations contained 58% tributyltin chloride by weight. Within two weeks of preparation, four groups of microencapsulated bodies were mixed with a marine basic coating agent. Basic paints are vinyl rosin A. F-paint (M & T Chemicals, Inc) was used and its components are listed in Table 1 below.

TABLE 1

About 8.2% of the paint mixture by weight was occupied by the fine coatings of tributyltin chloride. Then take 14 sandglass fiberglass panels, 8 inches by 10 inches, and divide 12 of them into 4 sets of 3 panels, one of four paints on one side of these panels. Painted separately.

The remaining three sets of panels were also painted in the same way with the remaining three types of paint. When painting, the painted film is dried naturally and then overcoated. Each paint film was about 5 mils thick. Except where otherwise indicated, the thickness of each paint film was close to 5 mils in all the examples described herein. Comparative paint was also used, the first comparative paint is a vinyl rosin basic paint containing no microfilm (Example 15), the second comparative paint is an inert, non-pollution hot oil (Dow Oil No. 550, Dow Chemical Co.) was prepared by mixing the microencapsule and the vinyl rosin basic paint. (Example 16) The high-temperature oil microfilms were mixed in the same concentration as the paint containing the tributyltin chloride microfilm. The microencapsule of dough oil was prepared by the procedure of Example 1 but did not use a finely divided inorganic emulsifier, it was required to add hydrochloric acid to adjust the pH of the mixture of the emulsion and colloidal solution to 4.5. Comparative paint was applied on a single layer on the other two panels. All 14 painted panels were submerged in Biscayne Bay, Dad County, Florida, so that the panel's tip was 1-4 feet below the surface of the water. The test panels were taken out at monthly intervals, evaluated by visual inspection, and immediately submerged in seawater. The overall performance of each test panel examined at monthly intervals is reported in Table II below. This overall performance chart reflects the panel's contamination resistance in consideration of the paint's adhesion, durability, pollution prevention, resistance to contamination, and corrosion protection as a coating suitable for use on metal surfaces. In Table II, 100 indicates that the panel is not contaminated, and 0 indicates complete contamination.

TABLE II

* Indicates peeling.

Example 17-30

According to the manufacturing process of Example 3-16, six kinds of paint compositions were prepared to contain 6.9% by weight of tributyltin chloride in the liquid state for each paint composition. In accordance with the procedure of Examples 3-16, 14 sanded glass fiber panels were painted and they were settled in water. All panels were taken out and inspected at monthly intervals and the overall scores were reported in Table III below.

TABLE III

* Indicates peeling.

Example 31-44

Six kinds of paint compositions were prepared by the procedure described in Example 3-16, but instead of vinyl rosin basic paint, chlorinated rubber A / F paint type 1A (3723-24-2) ( M & T Chemicals, Inc.) was used. The components of the chlorinated rubber basic paints are shown in Table IV below.

Table IV

Fourteen panels were painted with six different paint compositions and submerged according to the procedure described in Examples 3-16. These panels were taken out and inspected at monthly intervals and the overall performance was reported in Table V below as a percentage.

TABLE V

* Indicates peeling.

** Indicates no contamination.

Example 45-58

Six kinds of marine paint compositions were prepared according to the procedure of Example 17-30, but chlorinated rubber A / F paint type 1 (3723-24-2) was used instead of the vinyl rosin basic paint. Fourteen glass fiber panels were painted with six kinds of marine coating compositions by the procedure described in Examples 3-16 and submerged. These panels were taken out and inspected at monthly intervals, and the overall performance was reported in Table VI below.

Table VI

* Indicates peeling. ** Indicates loss of coating.

Example 59-62

Four groups of tributyltin chloride prepared by Example 3-16 were stored for four months, and then each of these four groups was mixed with a vinyl rosin basic paint to prepare four types of marine coating compositions. In each paint composition, 14% of the paint composition was weighted by the microencapsulation. Each of these four types of paint compositions was painted in one layer on four sanded glass fiber panels, followed by immersion according to the procedure of Example 3-16. These four panels were taken out and inspected at monthly intervals and the overall performance was reported in Table VII below.

[Table VII]

Example 63-66

The microencapsule of tributyltin chloride having a diameter of 1-10 μm was prepared by the procedure of Example 1, but the homogenizing step was performed by mixing the repair coating (No. 8223, petit paint Co., Inc, Belleville, NJ). It performed at high speed.

The microencapsulations accounted for 14% of the total coating composition by weight. This paint was applied in a single layer on one side of the sanded glass fiber panel and submerged according to the procedure described in Example 3-16 above. (Example 63)

The second marine coating composition was prepared by mixing 14% by weight of these micro-encapsulated body, 6.9% by weight of tributyltin chloride in liquid state, and 79.1% by weight of marine receiving paint. The paint was applied in a single layer on one side of the sanded fiberglass panel in the same way and submerged. (Example 64)

Two comparative paints were also tested. The first comparative paint was a basic marine repair paint without any pollution control system (Example 65), and the second comparative paint was a marine repair paint containing tributyltin chloride in liquid state. (Example 66) The tributyltin chloride accounted for 6.9% of the total coating composition in the second comparative paint.

Each of the comparative paints was painted in one layer on one side of the sanded glass fiber panel and then submerged as described in Examples 3-16 above. These four panels were taken out and inspected at monthly intervals and the overall performance was reported in Table VII below.

[Table VII]

Example 67-70

The first group of marine antifouling paints are prepared by adding the microencapsule of tributyltin chloride prepared in Examples 63-66 to the vinyl rosin basic paints used in Examples 3-16. About 14% of the composition was weighted by the microencapsulations. This paint was applied on a single layer of sanded glass fiber panels. Example 67 The second group was prepared by mixing 14% by weight of microencapsulated body, 6.9% of tributyltin chloride in liquid state, and 79.1% of vinyl rosin basic paint. This paint was applied in one layer on one side of the sanded fiberglass panel. Example 68 The vinyl rosin basic paint was painted on another panel as the first comparative paint (Example 69), and the vinyl rosin basic paint containing 6.9% by weight of tributyltin chloride in the liquid state was used as the second comparative paint. Sand was painted on the fourth fiberglass panel. (Example 70) The marine repair coating used in Examples 63-66 was single-coated on these four panels and dried to immerse as described in Example 3-16 above. Four panels were taken out and inspected at monthly intervals and the overall performance was reported in Table VII below.

[Table VII]

* Bubbles appear.

Example 71-74

Since the difference in the four groups of tributyltin chloride microencapsules prepared in Examples 3-16 did not appear in the previous examples, the third group containing 10-30 μm in diameter containing Cab-O-Sil Used in all of the following examples. Marine coating compositions were prepared by mixing tributyltin chloride microvinyl chloride and vinyl rosin basic paints stored in a dry state for 9 months. The weight of the coating composition was 14% of the total coating composition. The paint composition was applied on two layers of sand glass fiberglass panels. The marine repair paint used in Examples 63-66 was used to single coat one of these panels. (Example 72) For comparative purposes, on the third and fourth panels, a paint film of a paint composition containing a vinyl rosin basic paint and tributyltin chloride in liquid state was double coated. Here, tributyltin chloride accounted for 6.9% of the total coating composition by weight. One of these panels was covered with a single layer using marine repair paint. (Example 74) These four panels were submerged as described in Examples 3-16 above, removed and inspected at monthly intervals and the overall performance was reported in Table VII below.

[Table VII]

Example 75-86

A series of marine coating compositions were prepared to investigate the stability of the microencapsulated antifouling agent. The microencapsule of tributyltin chloride having a shelf life of less than one week was mixed with the vinyl rosin basic paint described in Examples 3-16, which accounted for 14% of the total coating composition by weight. Six paint-fiber panels were painted with this paint composition, two of which were divided into one layer, two into two layers, and the other two into three layers. One panel from each of the three types of panels was drawn and submerged as described in Example 3-16 above. (Examples 75-77) Using the ship's repair paint, the remaining three panels were single-layered and submerged. Examples 78-80 A marine coating composition containing four glass fibers covered with sand and containing by weight microfilms and vinyl rosin basic paints in an amount equivalent to 14% of the total coating composition. Each panel was painted with one wall, two with two layers, and one with three layers. Example 81-84 A marine paint composition containing microencapsulations was stored for 11 months before being applied to a panel. One of the two layers of panels was painted with a single layer of waterborne paint. (Example 84) These four panels were then submerged as described in Examples 3-16 above. Another marine coating composition was prepared by mixing the vinyl coating basic paint with the microencapsulated body in an amount corresponding to 14% of the total composition by weight.

These microencapsulations were stored for 14 months in a dry state before being mixed with the paint. Two varnished glass fiber panels were used to coat each layer of paint. One of these panels was covered with a single layer of marine repair paint. (Example 86) These two panels were submerged as described in Examples 3-16. Twelve panels were taken out and inspected at monthly intervals and the overall performance was reported in XI below.

TABLE VII

Claims (1)

In the composition of the marine antifouling paint containing at least 50% by weight of the ship's bottom paint, by dispersing the microencapsulant of the liquid antifouling agent that does not mix in the water coated with a cross-linked coacervate of gelatin type A and gum arabic Marine antifouling paint composition.