JP2005272320A - Algaecidal additive, method for producing the same and plastic plate and coating containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an algaecide which can effectively prevent algae entirely without considering safety and environmental pollution. <P>SOLUTION: This algaecidal additive contains an orthoferrite comprising at least one rare earth element selected from lanthanum, praseodymium, neodymium and yttrium, iron, and oxygen, as a main component. An algaecidal plastic plate contains the algaecidal additive in an amount of ≥5%. An algaecidal coating contains the algaecidal additive in an amount of ≥5%. A method for producing the algaecidal additive comprises mixing ferric oxide with the simple oxide of at least one rare earth element selected from lanthanum, praseodymium, neodymium and yttrium, or its compound giving the oxide, when fired, crushing the mixture, firing the crushed mixture to produce a fired product containing an orthoferrite as a main component, and then finely crushing the fired product. Another algaecidal additive contains the oxide of least one rare earth element selected from lanthanum, praseodymium, neodymium and yttrium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention mainly relates to anti-algae paints and anti-algae to be added to a plastic plate among a series of additives relating to fungi, anti-algae, and anti-shells applied to construction materials such as interior and exterior buildings, cooling towers, and ships. It relates to the agent.

  Antifouling agents are used in building materials for interior and exterior of buildings, structures such as cooling towers, and ships to prevent the generation and adhesion of mold, algae, and shellfish. Conventionally, organotin-based chemicals have been used widely for antifungal, algal and shellfish applications and have been widely used. However, since 1990, the use of anti-pollution and safety has been matched, and instead, the fungicide has an SH group, OH group, NH, which is an enzyme protein whose functional group controls the life of the organism. Instead of those that bind to the group and inactivate the enzyme and inhibit the growth of mold, the algae repellents are similar to those of organic nitrogen, sulfur and urea, and ship paints A large amount of cuprous oxide has been used with these drugs.

Although the above-mentioned drugs were sufficiently considered both in terms of effectiveness and safety, in addition to safety, environmental pollution has been regarded as a problem since around 1996. From JP-A-11-05392, JP-A-11-341974, JP-A-2000-312631, JP-A-2001-281552, JP-A-2002-20712, and so on. Anti-algae agents have been developed. These are often in the form of a metal powder such as Ag, Cu, Zn or the like, or an alloy or compound thereof held on an inorganic carrier, and use the toxicity of a trace amount of eluted ions, but compared to conventional drugs. It is characterized by slow elution.
Japanese Patent Laid-Open No. 11-05392 JP-A-11-341974 JP 2000-312631 A JP 2001-281552 A Japanese Patent Laid-Open No. 2002-20712

  As described above, an inorganic carrier type antifouling agent of metal powder or metal compound has been developed, and even if the degree of environmental pollution is reduced by using this, it takes time to prove its effect and to disseminate it. Therefore, at present, the conventional pharmaceutical-type algae deterrents are used under the control of the regulated amount considering environmental pollution. However, it is desirable to be able to provide an algae-proofing agent that can effectively prevent algae without relying on the elution of organic or inorganic chemical components and that does not require any consideration of safety or environmental pollution.

  An object of the present invention is to provide an algaeproofing agent that can effectively prevent algae without considering safety and environmental pollution at all.

  The additive for anti-algae according to the present invention is mainly composed of orthoferrite containing at least one rare earth element among lanthanum, praseodymium, neodymium and yttrium, iron and oxygen.

  In the additive for preventing algae, the rare earth element is, for example, a mixed rare earth mainly composed of lanthanum, praseodymium, and neodymium.

  In the above-mentioned additive for preventing algae, the rare earth element includes, for example, a plurality of elements in lanthanum, praseodymium, neodymium and yttrium.

  The plastic plate according to the present invention contains 5% or more of the above-mentioned additive for preventing algae. Alternatively, the plastic plate according to the present invention contains 10% or more of the above-mentioned additive for preventing algae.

  The paint according to the present invention contains 5% or more of the above-mentioned additive for preventing algae. Or the coating material which concerns on this invention contains 10% or more of said additives for anti-algae.

  In the method for producing an algal control additive according to the present invention, at least one elemental oxide of lanthanum, praseodymium, neodymium, and yttrium, and any one of a compound that is calcined to become an oxide and ferric oxide, Are mixed, pulverized, and fired to produce a fired body containing orthoferrite as a main component, and then the fired body is finely ground to produce an additive powder for preventing algae.

  The compound that becomes an oxide by firing is, for example, carbonate. Moreover, the compound which becomes an oxide by firing is, for example, a fluorinated carbonate.

  The second algal control additive according to the present invention is mainly composed of at least one rare earth oxide among lanthanum, praseodymium, neodymium and yttrium.

  One effect of the present invention is that it can safely and effectively prevent algae without considering any environmental pollution.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

a) Basic discovery.
In order to investigate the effects of far-infrared radiators on plant growth in the boom of room-temperature far-infrared radiators around 1993, we measured the far-infrared emissivity of materials for ceramics around us. An experiment was conducted to promote growth. The materials used were SiO ₂ (quartz), Al ₂ O ₃ (alumina), MgO—Al ₂ O ₃ —SiO ₂ (cordierite), Ca ₂ P ₂ O ₇ (apatite), MnO ₂ , Fe ₂ O _3. , ZrO ₂ , ZrSiO ₄ (zircon), TiO ₂ , FeTiO ₃ (ilmenite), Cr ₂ O ₃ , FeCr ₂ O ₄ (chromite), V ₂ O ₅ , Bi ₂ O ₃ , MoO ₃ , SnO ₂ , ZnO, 23 types of ThO ₂ , La ₂ O ₃ , CeO ₂ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , and Y ₂ O ₃ . About each of these materials, 20 g was put into a 200 cc polyethylene beaker, and 200 ml of goldfish breeding water was added and stirred, and left in a greenhouse. Then, when the amount of water was reduced to 3/4, it was added to the breeding water, and the developmental state of algae was observed for one year from November 1992.

The far-infrared emissivity measurement shows that even if there is a shift in wavelength, the emissivity is more than 80% of the high-infrared emitter. On the other hand, in the above experiment, in the observation of algae after one year, Fe ₂ O ₃ and ZnO, and La ₂ O ₃ , Pr ₆ O ₁₁ , Nd ₂ O ₃ and Y ₂ O ₃ are limited. The generation of algae was not observed, and growth was inhibited. (Slight algae generation was confirmed for CeO _2. ) Although the toxicity of ZnO has been known for some time, unexpected results can be obtained for Fe ₂ O ₃ and the rare earth oxides described above. Met.

In order to confirm whether the rare earth oxide algae growth-inhibiting property is due to the oxide alone or the type of compound is changed, taking lanthanum (La) as an example, La ₂ O ₃ , La ₂ (CO _{3 3} ) LaPO ₄ and LaF ₃ were prepared, and the growth of algae was observed from March 1993 to November 1993 under the same conditions as described above. Table 1 shows the results of observation of the types of lanthanum compounds and the growth of algae.

ここで、−は藻の生育の阻止を、＋は藻の生育の助長を示す。

Here,-indicates inhibition of algae growth, and + indicates promotion of algae growth.

From the results in Table 1, it can be seen that La oxide and carbonate inhibit the generation and growth of algae, whereas phosphate and fluoride promote the growth of algae. This property is obtained by adding sodium phosphate as a dispersant when La ₂ O ₃ and La ₂ (CO ₃ ) ₃ are easy to contain water, and La ₂ O ₃ is used as a material to make a ceramic for the purpose of preventing algae. This indicates that when a fluoride added for the purpose of adjusting viscosity, imparting gloss, and lowering the reaction temperature coexists, the ceramic obtained after firing may result in the deterioration of the algal resistance. This is a phenomenon that occurs not only with La ₂ O ₃ but also with other Pr ₆ O ₁₁ , Nd ₂ O ₃ , and Y ₂ O ₃ . Here, it was only confirmed that the rare earth compound acts unstablely as an accelerator and an inhibitor for the growth of algae depending on the kind of the algae, and no further pursuit was made at that time.

b) Development of anti-algae agents.
In 1997 (Heisei 9), the development of an algae-proofing agent that does not use chemicals was started, and the above-mentioned Fe ₂ O ₃ , La ₂ O ₃ , Pr ₆ O ₁₁ , Nd ₂ O ₃ and Y _{2 were started.} Interpretation of the phenomenon of O ₃ algae growth inhibition has become important. The conclusion was that Fe is a ferromagnetic material together with Ni and Co, the rare earth is 17 elements, and the heavy rare earth excluding the light rare earth is the ferromagnetic material next to Fe, Ni and Co. Since La to Sm are also magnetic materials having paramagnetism, it has been thought that these magnetisms may have a role in preventing the generation and development of algae.

_{Fe 2 O 3, La 2 O} 3 ~Pr 6 O 11, Y of 2 _{O 3} stable form of the magnetic material is ferrite, a ceramic magnet. When used for ceramic magnets for anti-algae, cobalt and nickel are difficult to use in terms of cost in iron, and only Fe ₂ O ₃ can be used, and La ₂ O ₃ is mainly used in rare earths. It seems that the mixed rare earth becomes the main material.

In order to investigate the coercive force of magnets suitable as an anti-algae agent, we investigated the coercive force of rare earth magnet materials on the market, and the algae generation and growth status of those refired products was the same as the above-mentioned algae observation experiment Depending on the conditions, the survey was conducted from February 1997 to November 1997. In addition, since there is no commercially available orthoferrite sample, La ₂ O ₃ and Fe ₂ O ₃ were mixed and adjusted at an equimolar ratio, and the fired one was mixed and adjusted at an equimolar ratio, and then fired. is there. Table 2 summarizes the results of algae-proofing experiments on commercially available rare earth magnet materials and their fired products.

Based on the results in Table 2, an orthorhombic perovskite of a sintered body of La ₂ O ₃ : Fe ₂ O ₃ = 1: 1 (mole) having a low coercive force among rare earth and ceramic magnets as a magnet material having a large anti-algae power. The ceramic magnet belonging to the orthoferrite having the mold structure is assumed to be the basic structure of the algaeproofing agent in the present invention.

c) Method for producing a rare earth orthoferrite anti-algae (LaFeO ₃ -based anti-algae).
Referring to earth orthoferrite _raw materials for the _Fe 2 _{O 3} of _{La 2 O 3 -Fe 2 O 3} , ferric oxide is used which is commercially available as ferrite for iron oxide. Light rare earth materials include monazite ((Th, RE) PO ₄ ), bastonite ((RE) CO ₃ F) (ie, rare earth fluoride carbonate), a mixed ore of monazite and bastonite. Mines are the main ones. All the rare earths were collected from the liquid from which thorium was removed after alkaline acid decomposition of monazite, and the lanthanum, cerium, praseodymium, neodymium and samarium were separated from the mixed rare earth solution by solvent extraction. A mixed rare earth called didium consisting mainly of lanthanum, praseodymium, and neodymium is a single rare earth, and the remaining rare earth is collected with ammonia water from the liquid obtained by separating cerium and heavy rare earth by acid treatment of the burnt material of bust nesite. It is. Rare earths such as yttrium are often separated from Chinese high yttrium mixed rare earth oxides (Yongnan).

The production of the LaFeO ₃ -based anti-algae will be described. An equimolar mixture (328: 158) of rare earth oxide equivalent rare earth compound and Fe ₂ O ₃ is placed in a tron mill containing an equal amount of porcelain balls, and water and a small amount The surfactant is added and milled for 24 hours. The extracted slurry is adjusted in concentration, then sent to a spray dryer, dried and granulated. The fine particle granulated material was put in a chamotte-shaped sheath and fired by maintaining it at 1,200 ° C. for 4 hours in a firing furnace, and after cooling, it was produced by a conventional method of crushing to a median diameter of 1 to 2 mm with a fine pulverizer.

  As the rare earth raw material, the separated simple rare earth lanthanum and yttrium can both be 90% or less in purity (about 800 yen / kg in terms of oxide) or mixed rare earth oxide (500 yen / kg). kg) and bust necite fired bodies (350 yen / kg) can be used experimentally, so it is possible to produce an orthoferrite anti-algae in consideration of economy.

d) Usage of anti-algae additives.
Orthoferrite (LaFeO ₃ ) -based anti-algae additive is an aqueous colloidal solution in which LaFeO ₃ -based anti-algae additive is dispersed in a commercially available coating composition such as acrylic, urethane, polyester, vinyl chloride, and phenol. In addition, a predetermined amount of the oily colloidal liquid is mixed and dispersed, and used as an algal barrier coating composition. For example, LaFeO ₃ powder as an anti-algae additive is dispersed in a resin composition composed of a thick-film binder (a polyamide-cured epoxy resin of amine (a mixture of radical polymerization type epoxy acrylate resin and styrene)).

  This algae-proof coating is applied to the surface of a substrate such as metal, wood, or plastic by a known method such as spraying, brushing, roll, dipping or the like. Subsequently, drying is performed to form a coating film on the surface of the substrate.

Further, to mold the resin sheet or a plastic plate powder LaFeO ₃ based anti algae additives. Here, when a granular material (compound) made of a polymer or various additives is melted, powder of an additive for LaFeO ₃ -based algae is added and dispersed, and poured into a mold. After cooling, it is removed from the mold to obtain a resin sheet or a plastic plate. It can be used mainly for cases used at the water's edge.

Paints, resin sheets, and plastic plates with LaFeO ₃ anti-algae additives dispersed are used especially on the exterior walls of houses, window frames, doors, shutters, and other watersides such as bathrooms, kitchens, and toilets. Suitable for departments where the occurrence of

  Ferrite-proof algae materials have the disadvantage of being colored yellow-brown. Currently, white-colored titanates are under investigation, and will be compiled together with application to ship bottom paint by confirming the anti-shell properties of orthoferrite. Is scheduled.

  In many cases, the use of the algaeproofing agent for the lanthanum orthoferrite magnet is kneaded into a resin sheet, or mixed with a paint. From the results of Examples 1 to 3 described below, it is predicted that the practical effect is great.

In order to examine the anti-algae properties of orthoferrite LaFeO ₃ , La ₂ O ₃ —Fe ₂ O ₃ ferrite was prototyped. At the same time, considering the economic efficiency when shifting to production in the future, the types of rare earth materials will be expanded and Di ₂ O ₃ (didium oxide) -Fe ₂ O ₃ , R ₂ O ₃ (mixed rare earth oxides) ) -Fe ₂ O ₃ and RCO ₃ F (bastonesite) -Fe ₂ O ₃ were simultaneously adjusted, and a test for anti-algae property was conducted. For comparison, goldfish breeding water and a fired neodymium-iron-boron magnet were used.

La ₂ O ₃ used for the preparation of the sample is 99.5% quality, and Di ₂ O ₃ is La ₂ O ₃ 58.5%, CeO ₂ 12.8%, Pr ₆ O ₁₁ 7.3%. , Nd ₂ O ₃ 18.5%, other 0.4%, Banestsite calcined ore (900 ° C.) is La ₂ O ₃ 24%, CeO ₂ 43%, Nd ₂ O ₃ 16%, Pr ₆ O ₁₁ containing 4%. To these all rare earth oxide powders, ferric oxide powder was sufficiently mixed at a molar ratio of 1: 1, and the fired product kept at 1200 ° C. for 4 hours was finely pulverized to obtain a median diameter of 1 to A 2 μm powder sample was prepared.

In the test method, 15 g of each of the four kinds of test samples were placed in a 200 cc polyethylene beaker, and 200 ml of goldfish breeding water was added and stirred, and left in a greenhouse. At the same time, as a comparative product, 200 ml of goldfish breeding water and 15 g of Nd—Fe—B magnet fired product prepared in Table 2 were similarly prepared. Evaporated water was added when it decreased to 3/4, and algae and growth conditions were regularly recorded at the end of November every year for five years from May 1998. Table 3 shows observation records of algae growth.

In the results of Table 3, in the comparative goldfish breeding water and the fired Ne-Fe-B magnet powder, the generation of algae was observed from around the 10th day, and the growth of dark green ones was continuously observed. However, the orthoferrites La ₂ O ₃ —Fe ₂ O ₃ , Di ₂ O ₃ —Fe ₂ O ₃ , and R ₂ O ₃ —Fe ₂ O ₃ may show no algae even after 4 or 5 years. could not. However, in the calcined Banestsite-Fe ₂ O ₃ , a slight amount of algae was observed on the upper wall portion after about 4 years. From these results, it was confirmed that the algal barrier property of the lanthanum orthoferrite itself persists for a long time.

Lanthanum orthoferrite anti-algae powder is press-molded by kneading 1%, 5% and 10% into PP (polypropylene) resin compound, and molded plate (width 50m / m, length 90m / m, thickness 2 m / m). The following five types of molded plates produced were prepared by preparing four types of lanthanum orthoferrite powder prepared in Example 1 and those not containing ferrite as a comparative example.
(1) PP plate containing 1%, 5%, and 10% of La ₂ O ₃ —Fe ₂ O ₃ powder (2) PP plate containing 1%, 5%, and 10% of Di ₂ O ₃ —Fe ₂ O ₃ powder (3) PP plate containing 1%, 5% and 10% of R ₂ O ₃ —Fe ₂ O ₃ powder (4) PP plate containing 1%, 5% and 10% of calcined Banestsite-Fe ₂ O ₃ powder ( 5) PP plate not containing ferrite as a comparative example

  Insert each of the above test plates into a 200cc polyethylene beaker in a nearly vertical shape, add the goldfish breeding water to the top edge of the beaker, leave it in the greenhouse, and if the water evaporates 2cm, the goldfish breeding water As a result, the algae growing mainly on the plate were observed for one year from November 1998 to November 2000. Table 4 shows the observation results of the state of adhesion and the degree of fixation of algae on the plate.

  According to the results in Table 4, the generation and growth of green algae proceed to the same extent on any polyethylene beaker wall. The algae on the board showed a dark green color on the comparative board and the four kinds of 1% -containing boards, and the algae was firmly fixed on the board. On the other hand, in both the 5% -containing plate and the 10% -containing plate, the algae had a blackish taste and had a low fixability that fell off as soon as it was touched. This suggests that more than 5% of the algae are dead or in the process. This experiment is performed in a static state, but if this is done in running water, the dead algae will be washed away and a clearer difference should be observable. From this experiment, it is known that the amount of the rare earth ferrite type algae to be kneaded into the plastic plate is desirably about 5% or more.

  As shown in FIG. 1, a 10 cm square tile plate 12 is pasted on the half of the surface of the A3 large plastic plate 10, one half leaves a resin paint coating frame 14, and the back half has a width of 5 cm and a length of 10 cm. Two sets of plastic plates having four kinds of base surfaces were prepared, in which two pieces of iron pieces 16 were bonded, and the remaining half was bonded two pieces of wood 18 having a width of 5 cm and a length of 10 cm. One was a test piece to which a paint containing an anti-algae agent was applied, and the other was a comparison piece to which only the same paint for comparison was applied. Support rods 20 and 24 and clip yarns 22 for suspending them in water were prepared.

The paint is a commercially available acrylic emulsion (50% solids), and 100 g of this liquid is mixed with 5 g of La ₂ O ₃ —Fe ₂ O ₃ anti-algae powder prepared in advance. All of this paint was applied onto the 10 cm square tile plate 12 with a brush. Subsequently, similarly prepared LaFeO ₃ paint was applied on the resin coating frame 14, similarly on the iron piece 16, and finally on the wood piece 18, and then dried for one week. 100 g of acrylic emulsion resin solution was applied on each of the tile 12, resin frame 14, iron piece 16, and wood piece 18 on the other plastic plate and dried in the same manner as a comparative example.

As shown in FIG. 2, the above-mentioned two plastic plates 10 coated with paint are hung on an infant tub 26, filled with water to the extent that the plastic plate 10 is covered, and the water pump 28 is operated to supply water at 8 o'clock. From 18:00 to 18:00. Breed 4-5 goldfish in it, feed and discharge as algae nutrition, sunshine can be obtained for 4-5 hours, water change on condition that 90% is replaced with 15-20 days as a cycle The observation was continued from October 5, 2002 to October 27, 2003. The recording was made on February 15, 2003, May 15, July 21, and 10/27. Table 5 _shows the recording of La _{2 O 3 -Fe 2} O 3 algae growth observed for different base of paint containing ferrite algae agent.

（浴槽の内壁には年間を通じて緑色藻の付着している環境で実験）

(Experiment in an environment where green algae adheres to the inner wall of the bathtub throughout the year)

According to the results in Table 5, it is known that in the comparative example, the algae are generated and grown smoothly from early summer to autumn. In the case of the LaFeO ₃ -containing paint, dark dirt adheres to the resin paint and the tile board at the height of the algae, and is almost removed in autumn. In the case of an iron plate or wood plate, a phenomenon is observed in which black stains are covered on the entire surface in the fall a little later. (This is not recorded here, but the record on February 10, 2004 shows that this black stain is getting thinner.) This stain is also attached to the plastic surface without the surrounding paint and is green. From the point of not exhibiting the color tone, it is not clear now whether it is regarded as adsorbing dirt or accumulation of dead alga. If black dirt is considered to overlap with the result of the observation of Example 2 and the dead alga, electromagnetic waves from the inherent magnetic field of the generated algae are absorbed by the anti-algae ferrite magnet in the paint and resonate to generate heat. As a result, the algae are killed, become dead bodies, accumulate for a period of time, and can be seen as black dirt. The wooden board containing iron and water as a metal acts as an electromagnetic wave shielding material, and the consumption of electromagnetic waves is more severe than on the resin board and tile board, so the amount of black dirt (dead bodies) produced has become conspicuous. It can be considered a thing. As a comparison, only the paint that does not contain LaFeO ₃ anti-algae agent has green algae in any period and any base, and there is almost no black dirt. It can be seen that the LaFeO ₃ anti-algae material has a great influence on the algae.

  In the above-described embodiment, an anti-algae agent for ortho-ferrite magnets mainly based on lanthanum, ortho-ferrite magnets manufactured based on didium oxide or mixed rare earth oxides has been described. However, neodymium, praseodymium or It is presumed that the orthoferrite magnet containing yttrium as a main component also has the same algal resistance as the orthoferrite magnet containing lanthanum as a main component.

e) Algae-proof mechanism of orthoferrite.
The invention using rare earth orthoferrite as an anti-algae agent is Fe ₂ O ₃ , La ₂ O ₃ , Pr ₆ O ₁₁ , Nd ₂ O ₃ , Y ₂ as materials that inhibit the generation of algae among far-infrared ceramic materials. Knowing that this is true for rare earth oxides such as O ₃ , these are all magnetic materials, and their most stable form is a ferrite magnet of rare earth oxides and Fe ₂ O ₃ In addition, the rare earth oxide: Fe ₂ O ₃ = 1: 1 (mole) orthoferrite of a magnet close to the plant's natural magnetic field is considered to be the most desirable form because of its coercive force, and this is used as an anti-algae. It is a selection.

As rare earth magnets, orthoferrite, orthorhombic ferrite, was first developed as a magnetic bubble material, compared to alloy and cubic ferrite (rare earth garnet), which are widely used as magnet materials. The current situation has been replaced by rare earth garnets due to the size of the bubble, and the main uses have not been developed. Therefore, there are few data as magnet materials. Examining the magnetic properties of orthoferrite, La is a paramagnetic substance, its magnetic susceptibility is 140 × 10 ⁻⁶ (= 10 ⁻⁴ ), Nd is 5600 × 10 ⁻⁶ (= 10 ⁻² ), and Fe is Similarly, 1700 × 10 ⁻⁶ (= 10 ⁻³ ) is measured, and on average, the magnetic susceptibility of lanthanum orthoferrite is 10 ⁻³ to 10 ⁻⁴ . The coercive force is 600 to 900 Oe, and the magnetic flux density is 300 to 500 G (all are estimated).

Algae such as chlorella, brorocox, ursolillas, oscillatria, and chlorocotozyme are self-synthesized as nutrients for algae, but are dissolved in water such as nitrogen, phosphorus, sulfur, potassium, and magnesium. Inorganic nutrition is also necessary, and light is indispensable. Taking Chlorella as an example, this is a kind of freshwater unicellular algae that are spherical and usually 3 to 10 μm in size, have chloroblasts in the cells, and grow by photosynthesis. Chloroblast is generally contained in cells of green plants that carry out photosynthesis and has a spindle shape. It has been estimated that the magnetic susceptibility of chloroblast is about the same as that of phthalocyanine (−530 × 10 ⁻⁶ ). From this, it is known that chlorella is a diamagnetic material and has a magnetic susceptibility of −10 ⁻³ to −10 ⁻⁴ . Chlorella, together with wheat grains, was measured to have a natural magnetic field value of 10 ⁻⁷ T, which is the same as the natural magnetic field of 10 ⁻⁷ T, and the average natural magnetic field (10 ^{− 4} T) is known to be about 1/1000.

  There is a literature that examined the influence of magnetic lines of force on chlorella, but this is the growth rate of chlorella under a magnetic field of 60 to 580 G under the condition of air blowing under light irradiation of 4100 lux. According to this, the growth rate constant is 2.8 / day at a magnetic field of 0 and slightly promoted to 2.9 / day at 400 G or less. 580G inhibits at 2.6 / day. When there is no light, there is no influence of the magnetic field. As a result, it is known that the strength of the magnetic field affects the growth of chlorella.

In the present invention, the algae are not a method of irradiating with external magnetic lines of force, but absorptive algae are absorbed by using electromagnetic absorption of physical properties of orthoferrite anti-algae to kill the algae. To be interpreted. In other words, electromagnetic waves (low frequency) generated from the magnets (chloroblast) of algae that have landed on a plastic plate or paint pass through the plate or paint film and are contained in the plastic plate or paint film. This is due to the method of resonance absorption and reduction in the dispersed La ₂ O ₃ —Fe ₂ O ₃ orthoferrite magnet powder. What is absorbed is that the electromagnetic wave of algae and the electromagnetic wave emitted by orthoferrite are in the same region, so that resonance vibration occurs, and the energy of the electromagnetic wave is lost as heat due to friction at that time. Since the ferrite magnet is spontaneously magnetized, its consumption is ignored. In this way, 10 ⁻⁷ T of the natural magnetic field of algae is reduced to 1/10 to 1/100, and finally died. This mechanism prevents the growth of algae. Since the orthoferrite magnet is a spontaneous magnet, its life is long. This is common to the current situation where high-frequency microwave protection is performed using (Ni, Zn) O—Fe ₂ O ₃ magnets as electromagnetic wave absorbers and metal powder and plates as shield materials.

  Many of the current algaecides are chemical methods that destroy enzymes that control the life of living organisms, or use the toxicity of trace ions eluted from metals and metal oxides. On the other hand, the orthoferrite anti-algae of the present invention is a method of killing algae by a physical method of resonantly absorbing electromagnetic waves generated by plants, and any aspect of safety, pollution prevention, and recent environmental protection This is a method with few problems. In addition, since orthoferrite anti-algae has a mechanism that uses electromagnetic absorption, and its usage is similar to that of low-frequency electromagnetic absorbers, its utilization will be further expanded if it can be combined with this application. It is expected.

The figure which shows the condition which applied the anti-algae paint on four types of base | substrates. Diagram showing the anti-algae test

Explanation of symbols

10 Plastic plate.

Claims (11)

An additive for anti-algae mainly composed of orthoferrite containing at least one rare earth element selected from lanthanum, praseodymium, neodymium and yttrium, iron and oxygen. The additive for anti-algae according to claim 1, wherein the rare earth element is a mixed rare earth mainly composed of lanthanum, praseodymium and neodymium. The additive for algae prevention according to claim 1, wherein the rare earth element contains a plurality of elements in lanthanum, praseodymium, neodymium and yttrium. A plastic plate containing 5% or more of the algae additive according to any one of claims 1 to 3. A plastic plate containing 10% or more of the anti-algae additive according to any one of claims 1 to 3. The coating material containing 5% or more of the algae control additive in any one of Claims 1-3. The coating material containing 10% or more of the algae control additive in any one of Claims 1-3. At least one rare earth element oxide of lanthanum, praseodymium, neodymium, and yttrium and any one of the compounds that are calcined to oxide and iron oxide are mixed, pulverized, calcined, and orthoferrite is obtained. Producing a fired body containing the main component,
This fired body is pulverized to produce additive powder for algae prevention.
A method for producing an additive for preventing algae. 9. The production method according to claim 8, wherein the compound that becomes an oxide upon firing is a carbonate. 9. The method according to claim 8, wherein the compound that becomes an oxide upon firing is a fluorinated carbonate. An additive for anti-algae comprising at least one rare earth oxide among lanthanum, praseodymium, neodymium and yttrium.

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