TW201509810A - Anti-fouling metal oxides encased with silicon dioxide - Google Patents

Abstract

Core-shell particles whose shell consists essentially of particulate silicon dioxide having a thickness of 0.1 to 10 [mu]m and whose core consists essentially of at least one anti-fouling metal oxide which is present in spherical and/or spheroidal form with an average particle diameter of 1 to 20 [mu]m.

Description

Anti-fouling metal oxide coated with cerium oxide

This invention relates to anti-fouling metal oxides coated with ceria and their manufacture and use.

Anti-fouling coatings comprising metal oxides are known. The main problem associated with the use of metal oxides is their exponential release. This represents the desire for a high metal oxide fraction in the coating under the assumption that there is a bioactive biocide concentration during the life of the coating.

U.S. Patent No. 7,147,921 teaches the problem of release by coating copper with a ruthenium dioxide film. What is actually observed is that, despite the cerium oxide film, the release of copper is still not as fast.

The technical problem addressed by the present invention is therefore to provide an anti-fouling material with a low concentration of biocide, with which the approximately linear release of these biocides is achieved, or the material is used for the same concentration of biocide A longer activity is achieved with the substance. Another issue addressed is to provide A method of making such materials.

The present invention provides a core-shell type particle whose shell is basically composed of particulate cerium oxide having a thickness of 0.1 to 10 μm (preferably 0.5 to 5 μm) and whose core is substantially at least one of an average particle diameter. It is composed of spheres of 1 to 20 micrometers (preferably 2 to 10 micrometers, preferably 3 to 7 micrometers) and/or anti-fouling metal oxides in the form of spheres.

"Substantially" means that the fraction of ceria in the shell and the fraction of anti-fouling metal oxide in the core are in each case at least 98% by weight, usually at least 99.5% by weight.

By "particulate form" it is meant herein that the cerium oxide does not surround the core in the form of viscous membranes and thus aggregates and/or cohesively to create elevations and depressions in the shell. Figure 1 shows an SEM micrograph of the particles of the present invention. The shell of the particles of the present invention cannot be considered to be dense compared to a dense membrane surrounding the core. It is believed that the particles form a porous shell and the porosity can be varied by the thickness of the film to likewise alter the release behavior of the metal oxide. The combination of the shell and the core is such that little or no detachment of the shell from the core is observed when dispersed, for example, with a dissolver.

The core of the core-shell type particle of the present invention has an approximate sphere or a similar sphere form. "About" means that deviations from the nuclear form of an ideal sphere or similar sphere are possible. The metal oxide present in the core is an anti-fouling metal oxide. Anti-fouling means that the metal oxide can retard, contain or prevent animals (including microorganisms) on objects that have been applied by applying such particles, particularly in contact with water, more particularly seawater. And surface colonization of plants. According to the invention, The metal oxide present in the core may be a single metal oxide, a physical mixture of two or more metal oxides, or a mixed oxide of two or more metal oxides. In the case of a mixed type oxide, the components of the mixed type oxide are intimately mixed at an atomic degree.

The anti-fouling metal oxide is preferably selected from the group consisting of copper oxide, titanium dioxide, iron oxide, manganese oxide, vanadium oxide, tin oxide, and zinc oxide.

Ideally suitable is a core-shell type particle whose core contains copper oxide as its main component or copper (I) as its main component. The composition of the core can be determined by, for example, X-ray diffraction.

The shell of the particles of the invention consists essentially of cerium oxide. Further, cerium oxide in the background of the present invention also contains vermiculite. He has a hydroxyl group on the surface of the other. The vermiculite preferably has an aggregated structure. The general representative of meteorites is smoky meteorites and precipitated meteorites.

Get the best results with fumed vermiculite. The smectite is produced, for example, by flame hydrolysis of a hydrazine compound such as chlorodecane. In this method, the hydrolyzable cerium halide is reacted with a flame formed by the combustion of hydrogen and an oxygen-containing gas. The burning flame here provides water for the hydrolysis of the hafnium halide and sufficient heat for the hydrolysis reaction. The vermiculite produced in this way is called a fumed vermiculite or a pyrolyzed hydrophilic vermiculite. In this procedure, the original particles are first formed and there is virtually no internal pores. During this procedure, these primary particles are fused to aggregates via so-called sintered necks to form a three-dimensional network. Multiple aggregates can eventually form a cohesive body.

A fumed vermiculite having a BET surface area of from 90 to 300 m 2 /g is preferred. The average primary particle diameter is preferably from 5 to 50 nm.

Hydrophobized vermiculite particles may also be part of the shell of the particles of the invention. These particles can be obtained, for example, by reacting a hydroxyl group present on the surface of the hydrophilic vermiculite with an organic decane, a halogen organodecane, a decane or a polyoxyalkylene. It is preferred to use octyltrimethoxydecane, octyltriethoxydecane, hexamethyldiazepine, 3-methylpropenyloxypropyltrimethoxydecane, 3-methylpropenyloxyl Propyltriethoxydecane, hexadecyltrimethoxynonane, hexadecyltriethoxydecane, dimethylpolyoxane, nonafluorohexyltrimethoxydecane, decafluorooctyltrimethoxydecane Tridecafluorooctyltriethoxydecane is used as an agent for hydrophobization. If the hydrophobized vermiculite is also utilized, the best results are obtained starting from the fumed vermiculite.

In a particular embodiment of the invention, the shell comprises a mixture of hydrophilic and hydrophobic cerium oxide particles.

The fraction of the anti-fouling metal oxide and cerium oxide can be varied over a wide range. The fraction of the anti-fouling metal oxide and cerium oxide is preferably from 30 to 70% by weight in each case, based on the core-shell type particles. In a particularly preferred embodiment, the fraction of the anti-fouling metal oxide is 50 to 60% by weight and the fraction of ceria is 40 to 50% by weight.

In a particular embodiment, the core-shell particles comprise from 80 to 90% by weight of the anti-fouling metal oxide based on the core-shell particles.

The fraction of the anti-fouling metal oxide and cerium oxide is in each case at least 98% by weight, preferably at least 99.5% by weight, based on the core-shell particles. The fraction of these components can be analyzed by chemical analysis or X-ray fluorescence Analytical determination.

The ratio of the average shell thickness to the average core diameter of the core-shell type particles is preferably 1:50 to 1:2 or 1.50 to 5:1, more preferably 1:10 to 1:3.

The core-shell particles of the present invention, as determined in accordance with DIN 66131, preferably have a BET surface area of from 30 to 150 square meters per gram and more preferably from 50 to 100 square meters per gram.

The present invention further provides a method of producing the core-shell type particle, wherein the specific energy is 200 to 2000 kilojoules/kg (preferably 500 to 1800 kilojoules/kg, and preferably 700 to 1500 kilojoules/kg). Input such that particles consisting essentially of cerium oxide are in contact with particles consisting essentially of at least one anti-fouling metal oxide selected from the group consisting of copper oxide, titanium dioxide, iron oxide, manganese oxide, vanadium oxide, Tin oxide and zinc oxide. The specific energy input is calculated as follows: specific energy input = (P _{D -} P _{D, 0} ) × t / m, where P _D = total input power P _{D, 0} = idle power t = energy input time m = cerium oxide And the quality of the metal oxide input material

With an assembly having a power of at least 1 kilowatt (preferably 1 to 20 kilowatts, more preferably 2 to 10 kilowatts), the energy input is at its optimum.

If the specific energy input is less than 200 kJ/kg or more than 2000 kJ/kg, the core-shell particles of the present invention are not obtained. Instead, think If less than 200 kilojoules per kilogram, a physical mixture of cerium oxide particles and metal oxide particles is formed. If more than 2000 kJ/kg, the structure of the input material is considered to be destroyed, i.e., the particles of the present invention are not available.

In a particular embodiment of the invention, a mixture of hydrophilic and hydrophobic cerium oxide particles is used for the contacting.

The contact in question is dry contact. This means that the liquid is not used in the method of the invention. However, moisture may stick to the input material, which may contain water of crystallization or may form a liquid reaction product.

This contact is preferably carried out in a rotor ball mill. The ball for polishing is preferably made of steel. When a rotor ball mill is used, the P _D is related to the total input power, that is, including cerium oxide, metal oxide, and grinding balls. P _D,0 describes the idle power, ie no cerium oxide, metal oxide and grinding balls. The filling volume of the input material in the rotor ball mill is preferably from 10 to 80% by volume, preferably from 20 to 50% by volume, based on the volume of the rotor ball mill in each case.

The contact time is preferably from 0.1 to 120 minutes, more preferably from 0.2 to 60 minutes, and most preferably from 0.5 to 10 minutes.

Relatively fine particles can be separated after this contact.

The tamped density of the particles consisting essentially of cerium oxide is preferably from 20 to 300 g/liter, more preferably from 50 to 200 g/liter. The packing density is determined by DIN EN ISO 787/11.

Preferably, copper (I) oxide and fumed vermiculite having a BET surface area of from 90 to 300 m 2 /g are used.

The invention further provides a coating comprising the core-shell particles. The fraction of the core-shell particles in the coating is preferably at least 5% by weight, more preferably from 10 to 60% by weight, based in each case on the coating.

The coating usually additionally contains a resin for film formation. Polymers suitable for this purpose are, for example, hydroxy or carboxyl containing acrylates, polyoxyxylene resins, polyesters or polyurethanes. Suitable curing agents are known to the skilled person.

The invention further provides a substrate coated with a coating of the invention. Suitable substrates include, in principle, all substrates, examples being made of metal, plastic or fiberglass. Correspondingly, the coating applied to the waters may be part of a sports boat, a merchant vessel, a structure immersed in water such as a breakwater, a dock, a drilling platform, a waterway traffic sign or a measuring probe.

The coating can be applied by known methods such as dipping, brushing, spraying or knife coating.

Figure 1 shows an SEM micrograph of the core-shell type particles of Example 1.

Figure 2 shows the results of the realistic examples 3a-c.

Example

Input material

AEROSIL ^® R805 (BET surface area 150 m ^ 2 / g, packing density of about 60 g / l), AEROSIL ^® / R9200 (BET surface area 150 to 190 m ^ 2 / g, packing density of about 200 g / l), both From Evonik Industries.

Copper oxide (I), Sigma-Aldrich; average particle size of 5.9 microns STANDART ^® Resist AT, Eckart. This material is copper coated with a ruthenium dioxide film and having a copper content of 97% and a BET surface area of 1 square meter per gram.

Simoloyer ^® CM05 Rotor Ball Mill, Zoz GmbH, Wenden.

As part of the invention, the shell thickness is calculated starting from the amount and size of the metal oxide used and the amount of cerium oxide particles utilized.

This calculation example shows that by having an average particle diameter of 0.06 kg of 5.9 microns ₅₀ d and 6000 kg / density ρ copper oxide, _{copper oxide,} and 0.04 kg of m ^ of having an average primary particle diameter of 12 nm and 200 d _{of the original} A kilogram per cubic _{meter of smoldering meteorite} with a density of 矽 。.

1) Volume of copper oxide:

V _{0, copper oxide} = 4/3‧π‧r ³ = π/6‧d ³ = π/6‧ (5.9‧10 ^-6 meters) ³ = 1.08‧10 ^-16 m ^ 3

2) Total volume of copper oxide:

V _{copper oxide} = m / ρ = 0.06 kg / (6000 kg / m ^ 3) = 1.00 ‧ 10 - ⁵ cubic meters of copper oxide particles: n _{copper oxide} = V _{copper oxide} / V _{0, copper oxide} = 9.29‧10 ¹⁰

3) Total volume of fumed vermiculite:

V _vermiculite = m / ρ = 0.04 kg / (200 kg / m ^ 3) = 2.00‧10 ^{- 4} m ^ 3

4) Assume that the smoky vermiculite is close to the sphere deposit on the copper oxide particles ΔV=the particle volume of the fluorite on each copper oxide particle ΔV=V _vermiculite /n _{copper oxide} =2.00‧10 ^-4 cubic Metric / (9.29‧10 ¹⁰ ) = 2.15‧10 ^-15 m ^ 3

5) Volume of copper oxide + vermiculite = V = V _{0, copper oxide} + △ V = 2.26‧10 ^-15 m ^ 3

6) Coating thickness

d ³ =V‧6/π;d=1.63‧10 ^-5 meters; △d=dd ₅₀ =1.04‧10 ^-5 meters

The thickness of the vermiculite shell is therefore 5.19 microns. The SEM/BSE evaluation showed that the fraction of the uncovered metal oxide particles and the cerium oxide particles not part of the shell was negligibly small or that the fraction did not exist at all.

In the case where the fumed vermiculite is also a component of the core-shell type particles of the present invention, it is observed that only the negligible effect of the coating layer is negligible or not at all, when the fumed vermiculite is incorporated into the preparation. Used to manufacture substrates resistant to fouling.

Example 1:

The grinding chamber of the rotor ball mill was filled with 66 grams of copper (I) oxide, 100 grams of AEROSIL ^® R805, and 7.5 kilograms of steel balls having a diameter of 4.8 millimeters and a density of 7550 kilograms per cubic meter. The total filling amount of the grinding chamber was 66%. After the filler has been introduced, the polishing chamber is covered with nitrogen. The mixer was rotated at 850 rpm. The grinding chamber is water cooled via its sleeve. This grinding time t is 2 minutes. The specific energy input is 825 kJ/kg. The resulting core-shell particles have a BET surface area of 70 square meters per gram. The packing density is 760 g/l. The shell thickness was calculated to be about 12.8 microns. Figure 1 shows an SEM micrograph of the core-shell particle. At the time of ultrasonic processing, significant peeling of the shell could not be detected. In other words, the shell is stable.

Example 2:

The grinding chamber of the rotor ball mill was filled with 100 grams of copper oxide (I), 66 grams of AEROSIL ^® R9200, and 7.5 kilograms of steel balls having a diameter of 4.8 millimeters and a density of 7550 kilograms per cubic meter. The total filling amount of the grinding chamber was 66%. After the filler has been introduced, the polishing chamber is covered with nitrogen. The mixer was rotated at 850 rpm. The grinding chamber is water cooled via its sleeve. This grinding time t is 2 minutes. The specific energy input is 825 kJ/kg. The shell thickness was calculated to be about 5.2 microns.

Example 3: Release of copper ions

Example 3a (for comparison): 0.625 grams of Cu ₂ O (corresponding to 1.1 g/liter of copper) was weighed out and placed in a grooved filter, and the grooved filter was sealed. The sealed grooved filter was placed in a glass bottle filled with 250 ml of seawater (Marine Broth, Difco 2216, sterilized) at 20 to 25 ° C and completely surrounded by the liquid. Stirring was carried out at 300 rpm using a magnetic stirrer, and copper evolution was measured every 30 minutes.

After oxidation with hydrogen peroxide, the measured Cu ²⁺ ions were measured by colorimetry.

Example 3b (comparison): As Example 3a, except that 0.275 g of from STANDART ^® Resist AT Eckart in place of Cu ₂ O. This is used as an anti-fouling agent in U.S. Patent 7,147,921.

Example 3c (invention): As in Example 3a, but 1.563 grams of the core-shell particles of Example 1 were used.

The results of Examples 3a-c are reported in Figure 2. In this figure, the concentration of Cu ²⁺ ions is plotted as a function of experimental time. In the figure, the comparison experiment 3a was marked with a circle, the comparison experiment 3b was marked with a diamond, and the experiment 3c of the present invention was marked with a square. The release of this Cu ²⁺ ion in experiments 3a and 3b was shown to be significantly faster than in Example 3c of the present invention.

Claims (19)

A core-shell type particle having a shell consisting essentially of particulate cerium oxide having a thickness of 0.1 to 10 micrometers and having a core substantially composed of at least one sphere having an average particle diameter of 1 to 20 micrometers and/or a sphere-like form. Made up of anti-fouling metal oxides. The core-shell particle of claim 1, wherein the anti-fouling metal oxide is selected from the group consisting of copper oxide, titanium dioxide, iron oxide, manganese oxide, vanadium oxide, tin oxide, and zinc oxide. The core-shell particle of claim 1 or 2, wherein the core component of the core is copper oxide (I). The core-shell particle of claim 1, wherein the shell comprises aggregated vermiculite particles. The core-shell particle of claim 1, wherein the shell comprises hydrophobized vermiculite particles. The core-shell type particle of claim 1, which contains 30 to 70% by weight of the anti-fouling metal oxide based on the core-shell type particle. The core-shell type particle of claim 1, which contains 80 to 90% by weight of the anti-fouling metal oxide based on the core-shell type particle. The core-shell particle of claim 1, wherein the ratio of the average shell thickness to the average core diameter is 1:50 to 1:2. The core-shell particles of claim 1 have a BET surface area of from 30 to 150 square meters per gram. The core-shell particles of claim 1 have a tamped density of 400-1000 g/l. A method of producing core-shell particles as claimed in claims 1 to 10, characterized in that the energy is input at a specific energy of 200 to 2000 kJ/kg so that particles consisting essentially of ceria are substantially At least one particle selected from the group consisting of anti-fouling metal oxides consisting of copper oxide, titanium dioxide, iron oxide, manganese oxide, vanadium oxide, tin oxide, and zinc oxide is contacted with each other. The method of claim 11, wherein the contacting is carried out in a rotor ball mill. The method of claim 11 or 12, wherein the contact time is from 0.1 to 120 minutes. The method of claim 11, wherein the relatively fine particles are separated after grinding. The method of claim 11, wherein the particles consisting essentially of cerium oxide have a packing density of from 20 to 300 g/l. The method of claim 11, wherein copper (I) oxide is used and fumed vermiculite is used. A core-shell type particle obtainable by the method of claims 11 to 16. A coating comprising core-shell particles as in claims 1 to 10. A coated substrate comprising a coating as claimed in claim 18.