JP7664801B2 - Rare earth ferrite dispersion resin liquid, products, and paints - Google Patents

Description

The present invention relates to a rare earth ferrite dispersion resin liquid, a product having a layer formed from the rare earth ferrite dispersion resin liquid, and a paint containing the rare earth ferrite dispersion resin liquid.

In recent years, ferrite compounds have been proposed as anti-algae agents that have low environmental pollution levels and are also safe. For example, Patent Document 1 discloses an anti-algae additive whose main component is orthoferrite, which contains rare earth elements selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), and yttrium (Y), iron, and oxygen, an anti-algae paint that uses the additive, and an anti-algae product in which the paint is applied to the surface of a substrate.

In Patent Document 1, the anti-algae effect is considered to be related to the magnetic property of the material, _and it is explained that orthoferrite with a rare earth oxide: _Fe2O3 =1:1 (molar ratio), which has a small coercive force and exhibits a magnetic force close to the intrinsic magnetic field of plants, is the most preferable anti-algae additive.

JP 2005-272320 A

In general, rare earth ferrites applied to building materials, ship bottoms, etc. are blended into paint, and the paint is applied to the surface of a substrate to form a rare earth ferrite-containing layer on the substrate. For this reason, it is preferable that the rare earth ferrite is uniformly dispersed in the paint.

The present invention has been made in consideration of the above background, and aims to provide a rare earth ferrite dispersion resin liquid that has high dispersibility of rare earth ferrite.

The present inventors conducted extensive research to solve the above problems. They discovered that a dispersion resin liquid in which rare earth ferrite is highly dispersible can be obtained by blending rare earth ferrite with a solvent-based acrylic resin having a reactive group with isocyanate, and thus completed the present invention. That is, the present invention is as follows.

Aspect 1
A rare earth ferrite represented by the following formula (1);
a solvent-based acrylic resin having a reactive group with isocyanate;
A rare earth ferrite dispersion resin liquid comprising:
Ln _2x Fe _{2 (1-x)} O ₃ (1)
(In formula (1), Ln is a rare earth element selected from the group consisting of lanthanum, praseodymium, neodymium, and yttrium, and x is a number equal to or greater than 0.45 and less than 1.00).
Aspect 2
The rare earth ferrite dispersion resin liquid according to aspect 1, wherein x in the formula (1) is a number of 0.55 or more and less than 1.00.
Aspect 3
The rare earth ferrite dispersion resin liquid according to aspect 1, wherein x in the formula (1) is a number of 0.55 or more and 0.75 or less.
Aspect 4
The rare earth ferrite dispersion resin liquid according to aspect 1 or 2, wherein Ln in the formula (1) is lanthanum.
Aspect 5
The rare earth ferrite dispersion resin liquid according to any one of aspects 1 to 4, wherein the rare earth ferrite is at least one selected from the group consisting of an anti-algae agent, an anti-fungal agent, and an antibacterial agent.
Aspect 6
1. An article of manufacture comprising a substrate and a rare earth ferrite-containing layer laminated or impregnated on the substrate,
The rare earth ferrite-containing layer is a layer formed from a treatment liquid containing the rare earth ferrite-dispersed resin liquid according to any one of aspects 1 to 5.
product.
Aspect 7
The product according to embodiment 6, which is selected from the group consisting of ships, seawalls, building materials, fishing nets, aquaculture nets, aquariums, pools, pool course ropes, buoys, and tiles.
Aspect 8
The product according to embodiment 6, which is selected from the group consisting of an exterior wall, an interior wall, a building material, an air filter, a packing, and a tank or pipe for storing or passing water.
Aspect 9
The product according to embodiment 6, which is selected from the group consisting of interior walls, building materials, joint materials, sealants, furniture, air filters, insoles, clothing, sanitary products, medical supplies or instruments, bath mats, towels, and bedding.
Aspect 10
A paint comprising the rare earth ferrite dispersion resin liquid according to any one of aspects 1 to 4.

The present invention provides a rare earth ferrite dispersion resin liquid that has high dispersibility of rare earth ferrite.

Treatment liquids such as coating liquids and impregnation liquids that use the rare earth ferrite dispersion resin liquid of the present invention become treatment liquids with high dispersibility of rare earth ferrite, and products that include a rare earth ferrite-containing layer formed from this treatment liquid can uniformly exhibit the anti-algae, anti-fungal, anti-bacterial, and other effects that are due to the rare earth ferrite.

<Rare earth ferrite dispersion resin liquid>
The rare earth ferrite dispersion resin liquid of the present invention contains a rare earth ferrite represented by the following formula (1) and a solvent-based acrylic resin having a group reactive with isocyanate.
Ln _2x Fe _{2 (1-x)} O ₃ (1)
(In formula (1), Ln is a rare earth element selected from the group consisting of lanthanum, praseodymium, neodymium, and yttrium, and x is a number equal to or greater than 0.45 and less than 1.00.)

According to the present invention, a rare earth ferrite dispersion resin liquid is provided that has high dispersibility of rare earth ferrite. Without being limited by theory, this is thought to be because, in a solution containing a solvent-based acrylic resin having a reactive group with isocyanate, an electrostatic interaction occurs between the charge bias in the resin caused by the reactive group with isocyanate and the charge possessed by the rare earth ferrite, which promotes the dispersion of rare earth ferrite particles.

The components of the rare earth ferrite dispersion resin liquid of the present invention are described below.

Rare earth ferrite
The rare earth ferrite used in the rare earth ferrite dispersion resin liquid of the present invention is a rare earth ferrite compound having a specific composition and is represented by the following formula (1):
Ln _2x Fe _{2 (1-x)} O ₃ (1)
(In formula (1), Ln is a rare earth element selected from the group consisting of lanthanum, praseodymium, neodymium, and yttrium, and x is a number equal to or greater than 0.45 and less than 1.00).

If the rare earth (Ln):Fe ratio in the rare earth ferrite is within the above range, a high anti-mold effect can be obtained.

The rare earth ferrite may be in any form as long as x in the above formula (1) is a number equal to or greater than 0.45 and less than 1.00. For example, it may form a solid solution having a uniform composition as a whole, may be a mixture of LnFeO3 _phase and _{Ln2O3 phase} , or may be a mixture of a solid solution having a uniform composition and _LnFeO3 phase and _{Ln2O3 phase} . It may also contain phases other than these.

In formula (1), x may be 0.50 or more, 0.55 or more, 0.56 or more, 0.57 or more, 0.58 or more, 0.59 or more, 0.60 or more, 0.65 or more, 0.70 or more, or 0.75 or more, or 0.95 or less, 0.90 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.70 or less, 0.65 or less, or 0.60 or less.

In the above formula (1), x may be, for example, a number equal to or greater than 0.55 and less than 1.00, or may be a number equal to or greater than 0.55 and equal to or less than 0.75. In this regard, as a result of detailed investigation into the composition of rare earth ferrite and its anti-algae effect, the present inventors have found that by setting the Ln:Fe ratio in the rare earth ferrite to a region richer in rare earth than 1:1 (molar ratio), (1) the dispersibility of the rare earth ferrite compound in the water-based urethane resin is improved, and (2) the anti-algae effect is improved and the duration of the effect is extended.

The rare earth (Ln) in formula (1) may be lanthanum, in particular, from the viewpoint of the excellent antifungal and antialgal properties of the resulting rare earth ferrite, and from the viewpoint of cost. Therefore, the rare earth ferrite used in the rare earth ferrite dispersion resin liquid of the present invention may be lanthanum ferrite.

<Rare earth ferrite content>
The content of rare earth ferrite in the rare earth ferrite dispersion resin liquid of the present invention may be, from the viewpoint of sufficiently ensuring dispersibility of the rare earth ferrite, for example, 1 mass % or more, 5 mass % or more, 10 mass % or more, 15 mass % or more, 20 mass % or more, 25 mass % or more, 30 mass % or more, 35 mass % or more, or 40 mass % or more, relative to the solid content of the solvent-based acrylic resin having a reactive group with isocyanate, and from the viewpoint of obtaining good coatability, it may be, for example, 80 mass % or less, 70 mass % or less, 60 mass % or less, 50 mass % or less, or 40 mass % or less.

<Method of manufacturing rare earth ferrite>
The method for producing the rare earth ferrite used in the present invention is not particularly limited. For example, the rare earth ferrite may be produced by applying an appropriate stress to a mixture containing a rare earth source and an iron source in a predetermined ratio, pulverizing and mixing the mixture, and then firing the mixture.

The stress applied here may be, for example, frictional force, shear force, shear stress, or impact force. A method for applying such stress to the mixture of the rare earth source and the iron source includes, for example, wet grinding in a ball mill.

As the rare earth source, for example, an oxide of the desired rare earth element may be used, or bastnaesite, monazite, xenotime, etc. may be used.

As the rare earth element, lanthanum is preferably used from the viewpoint of the excellent anti-algae, anti-fungal, and antibacterial properties of the obtained rare earth ferrite, and the cost. Among them, by using _La2O3 , it is possible to produce lanthanum ferrite that _is highly effective and relatively inexpensive.

As the iron source, oxides such as FeO, _Fe3O4 , _{Fe2O3 , etc} .; oxyoxides such as FeOOH, ferrihydrite, schwermannite _, etc.; hydroxides such as Fe(OH) ₂ , Fe(OH) ₃ , etc.; and the like may be used.

Among these, when FeOOH is used as the iron source, it has a higher reactivity than _Fe2O3 and _the like, so that it becomes possible to sinter at a low temperature, and it is also possible to produce rare earth _ferrite having a smaller particle size than _Fe2O3 and the like.

When the mixture of the rare earth source and the iron source is ground and mixed by wet grinding, for example, water, alcohol, etc. may be used as the liquid medium. After the mixture of the rare earth source and the iron source is ground and mixed, the liquid medium may be removed by an appropriate method such as heating and drying, if necessary, and then calcination may be performed.

The firing temperature is not particularly limited and can be set appropriately. For example, firing may be performed at a temperature of 700°C or more, 800°C or more, 900°C or more, or 1,000°C or more, and, for example, 1,300°C or less, 1,200°C or less, 1,100°C or less, or 1,000°C or less.

For example, if the temperature is in the range of 800°C or higher and 1000°C or lower, rare earth ferrite with even better anti-algae, anti-fungal, and antibacterial effects can be obtained.

The baking time is not particularly limited and can be set as appropriate. For example, the baking time may be 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, 6 hours or more, 8 hours or more, 12 hours or more, or 15 hours or more, and 72 hours or less, 48 hours or less, 36 hours or less, 24 hours or less, 18 hours or less, or 15 hours or less.

The surrounding atmosphere during firing may be an oxidizing atmosphere, for example, firing may be performed in air.

After firing, the rare earth ferrite that can be used in the present invention can be obtained by crushing, classifying, etc., using an appropriate method as necessary.

<Applications of rare earth ferrite>
Rare earth ferrites have low environmental pollution levels and are also highly safe, and therefore can be used for a variety of purposes.

Rare earth ferrites can be used for at least one application selected from the group consisting of, for example, anti-algae agents, anti-fungal agents, and antibacterial agents, and in particular, they exhibit excellent performance as anti-algae agents or anti-fungal agents.

For example, when used as an anti-algae agent, it can prevent the deterioration of the anti-algae effect over time, and when used as an anti-mold agent, it can exert an anti-mold effect on the surrounding area as well.

<Solvent-based acrylic resin having a reactive group with isocyanate>
The solvent-based acrylic resin having a reactive group with isocyanate used in the rare earth ferrite dispersion resin liquid of the present invention is not particularly limited, and may be any resin as long as the acrylic resin having a reactive group with isocyanate is dissolved or dispersed in a solvent that dissolves or disperses the resin.

Therefore, the solvent-based acrylic resin having a reactive group with isocyanate may be in a state where the resin is dissolved in a solvent, or in a state where the resin is dispersed in the solvent as an emulsion or solid.

The reactive groups with isocyanate that acrylic resins have are not particularly limited, but examples include hydroxyl groups and amino groups. Of these, hydroxyl groups are preferred.

When the solvent-based acrylic resin having a reactive group with isocyanate has a hydroxyl group, it is preferable that the hydroxyl value is high. A solvent-based acrylic resin with a high hydroxyl value can more easily adhere to rare earth ferrite particles, thereby increasing the dispersibility of the rare earth ferrite particles.

The hydroxyl value is not particularly limited, but may be, for example, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 120 or more, or 130 or more, and may be 180 or less, 170 or less, 160 or less, 150 or less, 140 or less, 130 or less, 120 or less, or 110 or less.

The solvent that constitutes the solvent-based acrylic resin having a reactive group with isocyanate is not particularly limited and may be any known solvent.

For example, various organic solvents such as alcohols such as ethanol, propanol, butanol, isopropyl alcohol, isobutyl alcohol, and diacetone alcohol; ethers such as methyl ether, ethyl ether, and propyl ether; esters such as ethyl acetate, butyl acetate, and isobutyl acetate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, ethyl isobutyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene, and benzene; aliphatic hydrocarbons such as normal hexane, heptane, and cyclohexane; glycol ethers such as propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; and mineral spirits can be mentioned. The solvent may be used alone or in combination of two or more types.

Commercially available solvent-based acrylic resins having a reactive group with isocyanate can be used, such as the Acrydic (registered trademark) series (DIC Corporation), which is an isocyanate-curing acrylic resin.

Other Ingredients
The rare earth ferrite dispersion resin liquid of the present invention may contain any component other than the rare earth ferrite and the solvent-based acrylic resin having a reactive group with isocyanate. Examples of the other components include resins, solvents, additives, etc. other than the components of the solvent-based acrylic resin having a reactive group with isocyanate.

<Resins other than the solvent-based acrylic resin having a reactive group with isocyanate>
The resin other than the solvent-based acrylic resin component having a reactive group with isocyanate, which is optionally contained in the rare earth ferrite dispersion resin liquid of the present invention, is not particularly limited, and may be, for example, an acrylic resin having no reactive group with isocyanate, an acrylic silicone resin, a silicone resin, an amino alkyd resin, an epoxy resin, a phenol resin, a polyurethane resin, an unsaturated polyester resin, a fluororesin, or the like.

<Solvent>
The solvent contained in the rare earth ferrite dispersion resin liquid of the present invention is not particularly limited, and may be, for example, at least one selected from the solvents constituting the above-mentioned solvent-based acrylic resin having a reactive group with isocyanate.

<<Method for producing rare earth ferrite dispersion resin liquid>>
The method for producing the rare earth ferrite dispersion resin liquid of the present invention is not particularly limited. For example, the liquid may be prepared by mixing a solvent-based acrylic resin having a reactive group with isocyanate, a rare earth ferrite, and other optional components in a predetermined ratio.

"product"
Another aspect of the present invention is a product comprising a substrate and a rare earth ferrite-containing layer laminated or impregnated in the substrate, the rare earth ferrite-containing layer being a layer formed from a treatment liquid such as a coating liquid or an impregnation liquid containing the rare earth ferrite-dispersed resin liquid of the present invention.

<Base>
The substrate in the product of the present invention may be any article to which rare earth ferrite is to be applied, including any article made of any material and having any shape, and any article to which the properties of rare earth ferrite are to be applied.

When the rare earth ferrite-containing layer is impregnated into the substrate, the substrate may be, for example, a woven or nonwoven fabric made of fibers, or a porous film, etc.

<Rare earth ferrite-containing layer>
The rare earth ferrite-containing layer in the product of the present invention is not particularly limited as long as it is a layer formed from a treatment liquid such as a coating liquid or an impregnation liquid containing the rare earth ferrite-dispersed resin liquid of the present invention. The rare earth ferrite-containing layer is laminated or impregnated on the substrate.

The rare earth ferrite-containing layer formed from the treatment liquid containing the rare earth ferrite dispersion resin liquid of the present invention contains rare earth ferrite and an acrylic resin having a reactive group with isocyanate as essential components, but the rare earth ferrite-containing layer may contain any other components. The optional components are not particularly limited, but include, for example, resins, binders, additives, etc.

The treatment liquid containing the rare earth ferrite dispersion resin liquid of the present invention for forming the rare earth ferrite-containing layer may be, for example, a mixture of the rare earth ferrite dispersion resin liquid of the present invention and a solution or dispersion containing other resins or additives, or a mixture of the rare earth ferrite dispersion resin liquid of the present invention to which other resins or additives have been added.

In the treatment liquid containing the rare earth ferrite dispersion resin liquid of the present invention for forming a rare earth ferrite-containing layer, the content of rare earth ferrite may be, for example, 1% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more as a ratio of rare earth ferrite to the total solid content of the treatment liquid from the viewpoint of fully expressing the performance of the rare earth ferrite, and may be, for example, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less from the viewpoint of obtaining good coatability.

The method for forming the rare earth ferrite-containing layer is not particularly limited, and examples include a method in which a treatment liquid containing a rare earth ferrite dispersion resin liquid is applied to a substrate and dried to form a hardened product, or a method in which a substrate is immersed in a treatment liquid containing a rare earth ferrite dispersion resin liquid, and the substrate is impregnated with the treatment liquid and then dried.

The thickness of the rare earth ferrite-containing layer is not particularly limited and may be, for example, about 1 μm or more and 1 mm or less.

The amount of the treatment liquid applied to form the rare earth ferrite-containing layer may be, in terms of the dry mass per unit area after removal of the solvent, for example, 5 g/m2 or ^more , 10 g/m2 or ^more , ¹⁵ g/m2 or more, 20 g/m2 or ^more , or 25 g/m2 or ^more , and may be, for example, 200 g/ ^m2 or less, 150 g/m2 or ^less , 120 g/m2 ^or less, 100 g/m2 or ^less , 80 g/m2 or ^less , or 70 g/ ^m2 or less.

<Other configurations>
The product of the present invention may include, as essential components, a substrate and a rare earth ferrite-containing layer laminated or impregnated in the substrate, and may also include other components. Examples of other components include other layers, and the other layers may be located outside the substrate, between the substrate and the rare earth ferrite-containing layer, or outside the rare earth ferrite-containing layer.

Another example of a layer is a primer layer formed on the substrate. Adhesion can be improved by forming a rare earth ferrite-containing layer on the primer layer.

In addition, the outside of the rare earth ferrite-containing layer may be covered with a resin or the like to prevent the rare earth ferrite from falling off or leaking due to long-term use, thereby preventing a decrease in the effectiveness of the rare earth ferrite.

Furthermore, by laminating a hue pigment layer or the like on the outside of the rare earth ferrite-containing layer, the degree of freedom in the color design of the product can be increased, and other functional layers can be laminated or combined to provide performance other than that of the rare earth ferrite.

<Applications>
The uses of the product of the present invention are not particularly limited, but when the rare earth ferrite is used as an anti-algae agent, the product may be, for example, a product selected from the group consisting of exterior walls, ships, revetments, building materials, fishing nets, aquaculture nets, aquariums, pools, pool course ropes, buoys, and tiles.

When rare earth ferrite is used as a mold inhibitor, it may be, for example, a product selected from the group consisting of exterior walls, interior walls, building materials, air filters, packing, and tanks or pipes for storing or passing water.

When rare earth ferrite is used as an antibacterial agent, it may be, for example, a product selected from the group consisting of interior walls, building materials, joint materials, sealants, furniture, air filters, insoles, clothing, sanitary products, medical supplies or equipment, bath mats, towels, and bedding.

"paint"
Another aspect of the present invention may be a paint containing the rare earth ferrite dispersion resin liquid of the present invention.

The paint may contain other components such as resin and solvent in addition to the rare earth ferrite dispersion resin liquid of the present invention.

The resins optionally contained in the paint are not particularly limited, and may be, for example, acrylic resin, acrylic silicone resin, silicone resin, amino alkyd resin, epoxy resin, phenolic resin, polyurethane resin, unsaturated polyester resin, fluororesin, etc.

The solvent contained in the paint is not particularly limited and may be selected from, for example, water, alcohol, ketone, aliphatic hydrocarbon, aromatic hydrocarbon, ester, etc.

In the paint, the content of rare earth ferrite may be, for example, 1% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more as a ratio of rare earth ferrite to the total solid content of the paint from the viewpoint of fully expressing the performance of the rare earth ferrite, and may be, for example, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less from the viewpoint of obtaining good coatability.

The method for producing the paint is not particularly limited. For example, the paint may be prepared by mixing a commercially available synthetic resin paint with the rare earth ferrite dispersion resin liquid of the present invention in a predetermined ratio.

<Applications>
The coating material of the present invention can be used to form the rare earth ferrite-containing layer in the above-mentioned product of the present invention. It may also be used as, for example, a joint material (a gap filler for tiles, concrete, bricks, etc.), a sealant, a caulking material, an adhesive, etc.

Example 1
<Preparation of lanthanum ferrite>
In a ball mill using 10 mm diameter alumina balls as grinding media, 0.25 mol parts _{of La2O3} , 0.5 mol parts of FeOOH, and water were charged and ground and mixed for 5 hours. The obtained ground product was dried at 300°C for 15 hours and then crushed with a rotary grinder. The obtained crushed product was fired at 1,000°C for 15 hours and then crushed with a hammer mill to obtain lanthanum ferrite (formula _LaFeO3 ) with La:Fe=50:50 (molar ratio).

<Preparation of lanthanum ferrite dispersed resin liquid>
The lanthanum ferrite prepared above was added to an isocyanate-curing acrylic resin (product name: ACRYDIC (registered trademark) A-801-P, DIC Corporation) in a composition with a solid content concentration of 30%. Furthermore, 20 g of zirconia beads with a diameter of 3 mm was added, and the mixture was stirred for 30 minutes with a paint shaker to obtain a lanthanum ferrite dispersion resin liquid.

<Dispersibility evaluation>
The prepared lanthanum ferrite dispersion resin liquid was allowed to stand for 4 days, and the dispersion state of the lanthanum ferrite after 4 days was visually evaluated according to the following evaluation criteria. The results are shown in Table 1.
⊚: No settling of lanthanum ferrite occurred and the lanthanum ferrite was uniformly dispersed. ◯: Settling of lanthanum ferrite had begun, but there was no boundary between the settling and the dispersed resin liquid.
Δ: Lanthanum ferrite precipitated, there was a boundary between the precipitate and the dispersed resin liquid, and the mixture was separated into two layers.
x: A large amount of lanthanum ferrite precipitated, the upper layer of the dispersion resin liquid became transparent, and the dispersion resin liquid was separated into three layers: the precipitate, the dispersion resin liquid, and the supernatant liquid.

Example 2 and Comparative Example 4
A lanthanum ferrite dispersion resin liquid was prepared in the same manner as in Example 1, except that the acrylic resin for constituting the dispersion resin liquid was changed to the product shown in Table 1. The dispersibility of the obtained lanthanum ferrite dispersion resin liquid was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

Examples 3 to 4, Comparative Examples 1 to 3, and Comparative Example 5
Lanthanum ferrite was synthesized in the same manner as in Example 1, except that the composition ratio was as shown in Table 1. Using the obtained lanthanum ferrite and the product shown in Table 1 as an acrylic resin, a lanthanum ferrite dispersion resin liquid was produced in the same manner as in Example 1. The obtained lanthanum ferrite dispersion resin liquid was subjected to a dispersibility evaluation in the same manner as in Example 1. The evaluation results are shown in Table 1.

From the above examples and comparative examples, it can be seen that (1) when rare earth ferrite is dispersed in a solvent-based acrylic resin having a reactive group with isocyanate, i.e., a solvent-based resin liquid in which an acrylic resin having a reactive group with isocyanate is dispersed, the dispersion of rare earth ferrite particles is promoted, and (2) regarding the molar ratio of rare earth (La) to iron (Fe), when the rare earth is equal to iron (La:Fe (molar ratio) = 50:50) or when the rare earth is greater than iron (La:Fe (molar ratio) = 60:40), the dispersion of rare earth ferrite is promoted more than when the rare earth is less than iron (La:Fe (molar ratio) = 40:60).

Reference Examples and Comparative Examples
The following reference examples and comparative examples show that by setting the Ln:Fe ratio in rare earth ferrite to a rare earth-rich region greater than 1:1 (molar ratio), the anti-algae effect is improved and the effect lasts for a longer period of time.

Reference Example 1
(1) Synthesis of lanthanum ferrite 0.3 mol parts of _La2O3 , 0.4 mol parts _of FeOOH, and water were charged into a ball mill using 10 mmΦ alumina balls as grinding media, and ground and mixed for 5 hours. The obtained ground product was dried at 300°C for 15 hours, and then crushed with a rotary grinder. The obtained crushed product was fired at 1,000°C for 15 hours, and then crushed with a hammer mill to obtain lanthanum ferrite (composition formula _La1.2Fe0.8O3 ) with La:Fe = _60:40 (molar _ratio ).

(2) Preparation of anti-algae coating liquid The obtained lanthanum ferrite was mixed into a commercially available synthetic resin paint (for concrete ponds, containing vinyl chloride resin) and mixed by shaking with a paint shaker to prepare an anti-algae coating liquid. The composition of this anti-algae coating liquid was adjusted so that the amount of lanthanum ferrite was 10 mass% relative to 90 mass parts of resin contained in the synthetic resin paint.

(3) Production of anti-algae product A polyethylene terephthalate (PET) film (thickness 50 μm) was used as the substrate, and the above-mentioned anti-algae coating liquid was applied to one side of the substrate using a wire bar #32, followed by drying at 60° C. for 2 days (48 hours) to produce an anti-algae product having an anti-algae layer on one side of the PET film. The coating amount of the anti-algae layer was 36.8 g/m ² .

(4) Evaluation of anti-algae products The obtained anti-algae products were cut into 5 cm x 5 cm squares to prepare evaluation samples, which were then hung with a string in a rectangular parallelepiped tank with a bottom area of 25 cm x 20 cm. Seawater collected from the ocean was poured into the tank to a depth of 10 cm, and the evaluation samples were completely submerged in the seawater. The tank in this state was left in an outdoor environment exposed to sunlight, and the state of algae adhesion to the coating surface was visually inspected at predetermined intervals and evaluated according to the following criteria. The evaluation results are shown in Table 2.
If no algae was found on the coated surface, it is marked as "-".
If the area of algae adhesion is 10% or less of the coated surface area: "+"
If the area of algae adhesion is more than 10% but less than 50% of the coated surface area, it is considered to be "++".
If the area of algae adhesion exceeds 50% of the coated surface area: "+++"

Reference Example 2
Except for changing the amounts of _La2O3 and FeOOH to 0.4 and 0.2 molar parts, respectively, lanthanum ferrite ₍ composition formula _La1.6Fe0.4O3 ) with La:Fe=80: ₂₀ (molar ratio) was synthesized in the same manner as in Reference Example 1, _and an anti-algae coating liquid was prepared using this, to produce an anti-algae product. The obtained anti-algae product was evaluated in the same manner as in Reference Example 1. The evaluation results are shown in Table 2.

Comparative Example 1
The anti-algae product was evaluated in the same manner as in Reference Example 1, except that the PET film not coated with the anti-algae coating liquid was cut into a 5 cm x 5 cm square and used as the evaluation sample. The evaluation results are shown in Table 2.

Comparative Example 2
Except for not blending lanthanum ferrite in the coating liquid, evaluation samples were prepared and evaluated in the same manner as in Reference Example 1. The evaluation results are shown in Table 2.

Comparative Examples 3 to 5
Except for changing the amounts _{of La2O3} and FeOOH as shown in Table 2, lanthanum ferrites with different La:Fe ratios were synthesized in the same manner as in Reference Example 1, and anti-algae coating solutions were prepared using these to produce anti-algae products. The obtained anti-algae products were evaluated in the same manner as in Reference Example 1. The evaluation results are shown in Table 2.

The results in Table 2 confirm that, compared to Reference Comparative Examples 1 and 2, which did not use lanthanum ferrite, Reference Comparative Examples 3 to 5 and Reference Example 1, which used lanthanum ferrite, exhibited anti-algae properties. However, anti-algae products using lanthanum ferrite with a La:Fe ratio of 50:50 (molar ratio) or a lower La ratio were unable to maintain anti-algae properties for a long period of time (Reference Comparative Examples 3 to 5).

In contrast, in the anti-algae products of Reference Example 1, in which the La:Fe ratio was 60:40 (molar ratio), and Reference Example 2, in which the La:Fe ratio was 80:20 (molar ratio), no algae were observed on the coating surface even after 8 weeks, demonstrating excellent anti-algae effects.

Reference Examples 3 to 5 and Comparative Examples 6 to 12
Lanthanum ferrites with different La:Fe ratios were synthesized in the same manner as in Reference Example 1, except that the amounts _{of La2O3} and FeOOH charged were changed as shown in Table 3. Using the obtained lanthanum ferrite, an anti-algae coating liquid was prepared in the same manner as in Reference Example 1, except that the amounts of lanthanum ferrite and resin blended were changed as shown in Table 3, and an anti-algae product was produced using this. The obtained anti-algae product was evaluated in the same manner as in Reference Example 1. The evaluation results are shown in Table 3, together with the results of Reference Examples 1 and 2, and Reference Comparative Examples 1 to 5.

According to Table 3, the anti-algae product of Reference Comparative Example 6, which has a La:Fe ratio of 42:58 (molar ratio), did not exhibit an anti-algae effect, similar to Reference Comparative Examples 1 and 2, which did not use lanthanum ferrite. In addition, the anti-algae products of Reference Comparative Examples 3, 7, and 8, which have a La:Fe ratio of 46:54 (molar ratio), exhibited some anti-algae effect, but the effect was low.

On the other hand, the anti-algae products of Comparative Examples 5, 11, and 12, which have a La:Fe ratio of 50:50 (molar ratio), exhibited a certain degree of anti-algae effect. However, with this La:Fe ratio, even if the amount of lanthanum ferrite was increased, the period during which the anti-algae properties of the anti-algae products were maintained was not extended.

In contrast, the anti-algae products of Reference Examples 1, 3, and 4, which had a La:Fe ratio of 60:40 (molar ratio), exhibited excellent anti-algae effects. Even in the case of Reference Example 2, in which the amount of lanthanum ferrite in the coating liquid was 2 mass%, it was confirmed that an excellent anti-algae effect was exhibited compared to Reference Comparative Examples 1 and 2, in which no lanthanum ferrite was used. Furthermore, a comparison of Reference Examples 1 and 4 with Reference Example 3 revealed that increasing the amount of lanthanum ferrite extended the period during which the anti-algae properties of the anti-algae product were maintained.

Similarly, it was confirmed that the anti-algae products of Reference Examples 2 and 5, which had a La:Fe ratio of 80:20 (molar ratio), also exhibited excellent anti-algae effects.

These results confirm that an anti-algae agent made from a specific amount of lanthanum ferrite exerts an excellent anti-algae effect even when used in small amounts, and that the period during which the anti-algae effect is maintained can be extended by increasing the amount of lanthanum ferrite used.

Claims (10)

A rare earth ferrite represented by the following formula (1);
a solvent-based acrylic resin having a hydroxyl group ;
A rare earth ferrite dispersion resin liquid comprising:
Ln _2x Fe _{2 (1-x)} O ₃ (1)
(In formula (1), Ln is a rare earth element selected from the group consisting of lanthanum, praseodymium, neodymium, and yttrium, and x is a number equal to or greater than 0.45 and less than 1.00). The rare earth ferrite dispersion resin liquid according to claim 1, wherein x in formula (1) is a number equal to or greater than 0.55 and less than 1.00. The rare earth ferrite dispersion resin liquid according to claim 1, wherein x in formula (1) is a number between 0.55 and 0.75. The rare earth ferrite dispersion resin liquid according to claim 1 or 2, wherein Ln in formula (1) is lanthanum. The rare earth ferrite dispersion resin liquid according to any one of claims 1 to 4, wherein the rare earth ferrite is at least one selected from the group consisting of an anti-algae agent, an anti-fungal agent, and an antibacterial agent. 1. An article of manufacture comprising a substrate and a rare earth ferrite-containing layer laminated or impregnated on the substrate,
The rare earth ferrite-containing layer is a layer formed from a treatment liquid containing the rare earth ferrite-dispersed resin liquid according to any one of claims 1 to 5.
product. The product according to claim 6, which is selected from the group consisting of ships, revetments, building materials, fishing nets, aquaculture nets, aquariums, pools, pool course ropes, buoys, and tiles. The product according to claim 6, which is selected from the group consisting of an exterior wall, an interior wall, a building material, an air filter, a packing, and a tank or pipe for storing or passing water. The product according to claim 6, which is selected from the group consisting of interior walls, building materials, joint materials, sealants, furniture, air filters, insoles, clothing, sanitary products, medical supplies or equipment, bath mats, towels, and bedding. A paint containing the rare earth ferrite dispersion resin liquid according to any one of claims 1 to 4.