JP2020111515A - Biological repellent and use thereof - Google Patents

Abstract

To provide a biological repellent that has a low environmental load and can exert repellent effect against various pests such as aquatic organisms and microorganisms.SOLUTION: Polysilane is used as a biological repellant. The polysilane may have at least one structural unit among the structural units represented by the following formulas (1) and (2). (In the formula, R1 to R3 are the same or different and each represents a hydrogen atom, a hydroxyl group, an organic group or a silyl group.).SELECTED DRAWING: None

Description

The present invention relates to a biorepellent (pest repellent) having a small environmental load and having a repellent action against various pests such as aquatic organisms and microorganisms, and its use.

Antifouling paints are used to attach fouling organisms in seawater, such as adhering organisms such as barnacles, mussels, hydrozoa, and scorpionfish, as well as adhering algae such as aonori and aosa, and slime-like substances (slime). Developed as a paint to prevent it, it is widely used in power plants, liquefied natural gas (LNG) vaporizers, intake pipes, submerged parts of structures, ship bottoms, fishing gear such as aquaculture and stationary fishing nets, and ocean observation equipment. .. In particular, since marine organisms such as barnacles attached to the bottom of the ship have great resistance to navigation, antifouling paint is applied to the bottom of the boat to prevent the adhesion of marine organisms.

As antifouling agents used in antifouling paints, cuprous oxide, organic tin compounds, organic nitrogen-sulfur compounds, etc. are known. Despite the excellent antifouling performance of organotin compounds, toxicity (accumulation) to fish has become a problem, and tributyltin, a typical antifouling agent, has been banned globally since 2008 by the International Maritime Organization Treaty. Therefore, it is desired to develop an antifouling agent having a small environmental load, which is an alternative to the organic tin compound.

Japanese Unexamined Patent Publication No. 2000-198965 (Patent Document 1) discloses that monazite powder 40-60% by weight and tourmaline powder 60-40% by weight having an average particle diameter of 3 to 10 μm that constantly emit negative ions. Disclosed is an additive for antifouling paint, which is mainly composed of a mixture of

However, this additive for antifouling paint is a natural mineral, it is difficult to supply it stably, and productivity and economic efficiency are low.

JP-A-2000-198965 (claim 1)

Therefore, it is an object of the present invention to provide a biorepellent agent which has a small environmental load and can exert a repellent effect against various pests such as aquatic organisms and microorganisms, and its use.

Another object of the present invention is to provide a biorepellent having high productivity and high antifouling property, and its use.

The present inventors have conducted intensive studies to achieve the above-mentioned problems, and compared to conventional antifoulants, polysilane having a small environmental load has a repellent effect against various pests such as aquatic organisms and microorganisms. Heading, the present invention was completed.

That is, the biorepellent agent of the present invention comprises polysilane. The polysilane may have at least one structural unit among the structural units represented by the following formulas (1) and (2).

(In the formula, R ^{1 to} R ³ are the same or different and represent a hydrogen atom, a hydroxyl group, an organic group or a silyl group).

The polysilane may be a polyalkylarylsilane having a weight average molecular weight of 100 to 10,000.

The present invention also includes methods of using the biorepellents to repel pests such as aquatic organisms and/or microorganisms. The present invention also includes a method of using the biorepellent agent for preventing aquatic organisms from adhering to the surface of an underwater member (such as the bottom of a ship).

The present invention also includes an antifouling paint containing the biorepellent agent. The antifouling paint may be a ship bottom coating agent.

In the present invention, since polysilane having high safety is used, it is possible to exert a repellent effect against various pests such as aquatic organisms and microorganisms although the environmental load is small. Furthermore, since polysilane is industrially easily mass-produced, it has high productivity and excellent mold releasability, so it is effective to prevent marine organisms from adhering to the submerged member surface from both biological and physical aspects. Can be effectively prevented and has excellent antifouling properties. Therefore, the biorepellent agent of the present invention is also suitable as an additive or an antifouling agent for antifouling paints.

It is a graph which compared the viable cell count of a culture solution in Example 1 and Comparative Example 1. FIG. 2 is a photograph of LB agar medium after culturing for 2 days in Example 1. FIG. 3 is a photograph of LB agar medium after culturing for 2 days in Comparative Example 1.

[Polysilane]
The antifouling agent of the present invention comprises polysilane. The present inventors have found that polysilane has a repellent action against organisms, and also found that it is effective as an antifouling agent because it can prevent aquatic organisms from adhering to the surface of members in water.

Polysilane is not particularly limited as long as it is a chain (linear or branched), cyclic or network (network) compound having a Si—Si bond. Examples of structural units (silane units) constituting these polysilanes include structural units [silane units (1) to (4)] represented by the following formulas (1) to (4). Usually, polysilane often has at least one structural unit among the structural units represented by the following formulas (1) and (2). The molecular structure of polysilane is preferably linear (linear or branched) or cyclic.

(In the formula, R ^{1 to} R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, an organic group or a silyl group).

In the formulas (1) to (2) and (4), examples of the organic group represented by R ^{1 to} R ⁶ include a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group and an aralkyloxy group. It can be exemplified and is usually a hydrocarbon group in many cases.

As the hydrocarbon group, a linear or branched alkyl group (alkyl group), an aryl group, a cycloalkyl group (for example, a C _5-10 cycloalkyl group such as cyclopentyl or cyclohexyl group), an aralkyl group (for example, Benzyl group, C _6-12 aryl-C _1-4 alkyl group such as phenethyl group), alkenyl group (eg C _2-6 alkenyl group such as vinyl group, allyl group, etc.), cycloalkenyl group (eg cyclo Examples thereof include C _5-10 cycloalkenyl groups such as pentenyl group and cyclohexenyl group). These hydrocarbon groups can be used alone or in combination of two or more. Of these, an alkyl group and an aryl group are preferable.

Examples of the alkyl group include linear or branched C _1-10 alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, t-butyl group and pentyl group. These alkyl groups can be used alone or in combination of two or more. Of these, a C _1-6 alkyl group is preferable, a C _1-4 alkyl group such as a methyl group or an ethyl group is more preferable, and a methyl group is most preferable.

Examples of the aryl group include a C _6-12 aryl group such as a phenyl group and a naphthyl group, etc., preferably a C _6-10 aryl group, and more preferably a phenyl group. The aryl group may have a substituent. The number of the substituents is not particularly limited and may be, for example, one or a plurality (for example, 2 to 4), and in the case of a plurality, the types of the substituents may be different. Examples of the aryl group having such a substituent include a C _1-6 alkyl C _6-10 aryl group such as a tolyl group, a xylyl group, an ethylphenyl group, and a methylnaphthyl group (for example, a mono to tri C _1-4. Alkyl C _6-10 aryl groups, especially mono- or di-C _1-4 alkylphenyl groups, etc.) and the like.

Among these hydrocarbon groups, an alkyl group (especially a C _1-4 alkyl group such as a methyl group and an ethyl group) and an aryl group (especially a phenyl group) are preferable from the viewpoint of excellent biorepellency and solubility in an organic solvent. preferable.

In the formula (1), the combination of R ¹ and R ² is preferably at least one of alkyl and aryl groups may be the same as the R ¹ and R ^2, be different Good. Examples of the combination of R ¹ and R ² include alkyl groups [eg, C _1-4 alkyl group (especially methyl group or ethyl group)], aryl groups (especially phenyl group), alkyl groups and aryl groups. It may be a combination. In particular, the combination of R ¹ and R ² improves the biorepellency and the solubility in organic solvents, and thus an alkyl group [for example, a C _1-4 alkyl group (especially methyl group)] and an aryl group [especially a phenyl group]. ] And a combination of a methyl group or an ethyl group (particularly a methyl group) and a phenyl group is particularly preferable.

The ratio of the silane unit (1) and the silane unit (2) can be selected from a wide range of the former/the latter (molar ratio)=10/90 to 100/0, and for example, 50/50 to 100/0 (for example, 55/ 45 to 90/10), preferably 60/40 to 100/0 (for example, 65/35 to 85/15), more preferably 70/30 to 100/0 (particularly 75/25 to 80/20). Or only the silane unit (1) (100/0).

The total ratio of the silane unit (1) and the silane unit (2) with respect to the entire polysilane can be selected from a wide range of 10 to 100 mol%, for example, 30 mol% or more (for example, 40 to 90 mol%), preferably 50 mol%. It may be at least (for example, 60 to 85 mol%), more preferably at least 70 mol% (for example, 75 to 80 mol%), and particularly at least 90 mol%.

The ratio of the silane unit (3) to the entire polysilane may be, for example, about 0 to 20 mol% (eg, 1 to 10 mol%, preferably 2 to 5 mol%).

The ratio of the silane unit (4) to the entire polysilane may be, for example, about 0 to 40 mol% (eg, 1 to 20 mol%, preferably 5 to 10 mol%).

At least a part of the end groups of the polysilane may be silanol groups (hydroxyl groups). When the terminal group is a silanol group (hydroxyl group), when used as a paint, the mechanical strength and abrasion resistance of the coating film can be improved by the reaction or bonding with the silanol group and the resin component having a functional group. It is advantageous.

The polymerization form of polysilane is not particularly limited, and may be a homopolymer or a copolymer (for example, a random copolymer, a graft copolymer, a block copolymer, etc.).

Preferred polysilanes include linear or cyclic polysilanes having the structural unit represented by the above formula (1), preferably polydialkylsilanes, polyalkylarylsilanes, polydiarylsilanes, copolymers of these polysilanes, More preferably, linear polyalkylarylsilane, cyclic polydiarylsilane (eg, cyclic polydiphenylsilane), and particularly linear _{polyC 1-2 alkylC 6-10} arylsilane (eg, polymethylphenylsilane) is preferable. ..

The polysilane preferably does not have a siloxane bond (—Si—O—Si—), but it may inevitably have a very small amount of siloxane bond.

The average degree of polymerization of polysilane is about 250 or less (for example, 2 to 100) in terms of silicon atom (that is, the average number of silicon atoms per molecule), for example, 2 to 30, preferably 2 to 20, and more preferably. It may be about 3 to 10 (particularly 4 to 8). If the degree of polymerization is too large, the compatibility and the like may decrease when used as an additive for antifouling paints and the like.

As the molecular weight, for example, the weight average molecular weight is about 30,000 or less, for example, 100 to 10,000, preferably 300 to 3,000, more preferably 500 to 1,000 (particularly 600 to 800); and the number average molecular weight is also 30,000 or less. For example, it may be about 100 to 10000, preferably 300 to 3000, and more preferably 400 to 1000 (particularly 500 to 700). The dispersity (M _w /M _n ) may be, for example, 1 to 5, preferably 1 to 3, more preferably 1 to 2, and especially 1 to 1.5. The weight average molecular weight (M _w ) and number average molecular weight (M _n ) of polysilane can be measured by GPC in terms of polystyrene.

These polysilanes may be commercially available products or may be prepared. In the case of preparation, various preparation methods using halosilanes having units represented by the above formulas (1) to (4), for example, a method of dehalogenative condensation polymerization of halosilanes with magnesium as a reducing agent (“magnesium reduction Method”) and the like.

The biorepellent agent of the present invention is used alone for the purpose of antifouling, insecticidal, insecticidal, herbicidal, bactericidal, antibacterial, bactericidal, etc. against various pests by utilizing the biological repellent effect. May be used as an additive to liquid dispersions or gels, aerosols, slow or sustained vapor or smoke generating compositions, foam compositions, solid compositions such as powders or granules, microcapsules, etc. You may. Especially, since polysilane has releasability in addition to the biological repellent effect, it can not only repel the living organisms but also physically prevent the living organisms from adhering to the member. Therefore, the biorepellent agent of the present invention is preferably used as an additive for antifouling paints.

[Anti-fouling paint]
The antifouling paint of the present invention contains the biorepellent agent. The proportion of the biorepellent agent in the paint can be selected from the range of about 0.1 to 99% by mass, for example, 10 to 95% by mass, preferably 20 to 90% by mass, more preferably 30 to 80% by mass (particularly 50 to 50% by mass). 70% by mass). When the biorepellent agent is combined with another antifouling agent, the proportion of the biorepellent agent in the paint is, for example, 1 to 80% by mass, preferably 3 to 70% by mass, more preferably 5 to 50% by mass (particularly 10 to 10% by mass). About 30% by mass). If the proportion of the biorepellent agent is too small, the antifouling property may decrease, and if it is too large, the film forming property of the coating composition may decrease.

The antifouling paint of the present invention may contain, as a film-forming component, a binder which is conventionally used in antifouling paints, in addition to the biorepellent agent. Examples of the binder include a thermoplastic resin [olefin resin (polyethylene, polypropylene, modified polyolefin modified with a carboxyl group or an acid anhydride group, polyolefin modified with an epoxy group, etc.), acrylic resin ((meth)) Acrylic ester-based polymers, carboxyl group-containing acrylic resins, hydroxyl group-containing acrylic resins, epoxy group-containing acrylic resins, etc.), styrene-based resins (copolymers of styrene and (meth)acrylic-based monomers, etc.), acetic acid Vinyl resin (polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl acetate-vinyl chloride copolymer, etc.), vinyl alcohol polymer (polyvinyl alcohol, ethylene-vinyl alcohol copolymer, etc.), vinyl chloride resin (Polyvinyl chloride, vinyl chloride-vinyl isobutyl ether copolymer, vinyl chloride-vinyl acetate copolymer, etc.), vinyl ether polymer (polyvinyl methyl ether, polyvinyl isobutyl ether and other polyvinyl alkyl ethers, methyl vinyl ether-maleic anhydride) C _1-6 alkyl vinyl ether-maleic anhydride copolymer such as copolymer), polyester resin (copolymerized polyester resin, modified polyester resin, etc.), polyurethane resin, polyamide resin, cellulose derivative (methyl cellulose, hydroxyethyl cellulose, carboxy) Cellulose ether such as methyl cellulose; cellulose ester such as cellulose acetate), etc.], thermosetting resin [epoxy resin, phenol resin, urethane resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, silicone resin, amino resin ( Urea resin, melamine resin such as methylolated melamine resin, etc.), photo-curable resin [photo-curable oligomer such as epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, polyfunctional (meth) ) Acrylate, photocurable monomers such as nitrogen-containing monomers], rubbers [for example, chlorinated rubber; halogenated polyolefins (chlorinated polyolefins such as chlorinated polyethylene and chlorinated polypropylene; chlorosulfonated polyolefins such as chlorosulfonated polyethylene) ), etc.], tackifying components or elution promoting components [including natural resins (eg, rosin or its derivatives (rosin, rosin ester, rosin-modified resin, etc.), lac, styrax, etc. Tellur natural resin); waxes such as chlorinated paraffin; fats and oils or derivatives thereof (glycerides such as flaxseed oil, polymerized oils such as polymerized flaxseed oil) and the like] and the like.

These binders can be used alone or in combination of two or more. Further, these binders can be selected depending on the application, and an antifouling paint containing a thermoplastic resin or an antifouling paint containing a curable resin such as a thermosetting resin or a photocurable resin is preferable.

The proportion of the binder is, for example, 1 to 200 parts by mass, preferably 5 to 150 parts by mass (for example, 10 to 100 parts by mass), and more preferably 30 to 80 parts by mass (particularly 40 to 40 parts by mass) with respect to 100 parts by mass of the biorepellent agent. 60 parts by mass). If the proportion of the binder is too small, the film-forming property of the paint may be deteriorated, and if it is too large, the antifouling property may be deteriorated.

The antifouling paint of the present invention may further contain a conventional antifouling agent in addition to the biorepellent agent. Examples of the antifouling agent include cuprous oxide, copper alloy, cuprous rhodanate, manganese ethylene bisdithiocarbamate, zinc dimethyldithiocarbamate, 2-methylthio-4-t-butylamino-6-cyclopropylamino-s. -Triazine, 2,4,5,6-tetrachloroisophthalonitrile, N,N-dimethyldichlorophenylurea, zinc ethylenebisdithiocarbamate, 4,5-dichloro-2-N-octyl-3(2H)isothiazolone, N Examples thereof include -(fluorodichloromethylthio)-phthalimide, N,N-dimethyl-N'-phenyl-(N-fluorodichloromethylthio)sulfamide, tetramethylthiuram disulfide, and 2,4,6-trichlorophenylmaleimide. These antifouling agents can be used alone or in combination of two or more kinds.

The ratio of the antifouling agent is about 200 parts by mass or less with respect to 100 parts by mass of the biorepellent agent, for example, 0.1 to 200 parts by mass, preferably 1 to 150 parts by mass, and more preferably 5 to 100 parts by mass ( In particular, it is about 10 to 50 parts by mass). If the proportion of the antifouling agent is too large, the antifouling property may be reduced.

The antifouling paint of the present invention may further contain a solvent. The solvent may be water or an organic solvent. The organic solvent is not particularly limited, and examples thereof include hydrocarbons [eg, aromatic hydrocarbons (eg, benzene, toluene, xylene, etc.), alicyclic hydrocarbons (eg, cyclohexane, etc.), aliphatic hydrocarbons, etc. Hydrogens (eg, heptane, mineral spirits, etc.)], ketones (eg, diC _1-4 dialkylketone such as methylethylketone), esters (eg, C _1-6 alkyl acetate such as ethyl acetate, butyl acetate) Ester, etc.), alcohols (for example, monohydric alcohols such as methanol, ethanol, butanol, polyhydric alcohols such as ethylene glycol, diethylene glycol, etc.), cellosolves (for example, C _1-6 such as methyl cellosolve, ethyl cellosolve, etc. Alkyl cellosolves and the like), carbitols (for example, C _1-4 alkyl carbitols such as methyl carbitol and ethyl carbitol), glycol ether esters (for example, cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether). Examples thereof include acetate and the like, terpenes and the like. These solvents can be used alone or as a mixed solvent.

The ratio of the solvent is, for example, 1 to 200 parts by mass, preferably 5 to 150 parts by mass (for example, 10 to 100 parts by mass), and more preferably 30 to 80 parts by mass (particularly 40 to 40 parts by mass) with respect to 100 parts by mass of the biorepellent agent. 60 parts by mass). If the proportion of the solvent is too small, the handleability of the coating material may be deteriorated. On the contrary, if the proportion is too large, it may be difficult to form a thick coating film.

The antifouling paint of the present invention may further contain a conventional additive that is mixed with the antifouling paint. Examples of conventional additives include fillers, dehydrating agents, wetting agents, stabilizers (antioxidants, antiozonants, ultraviolet absorbers, heat stabilizers, light stabilizers, etc.), plasticizers, softeners, Lubricants, mold release agents, thickeners, antistatic agents, flame retardants, dispersants, surfactants, colorants, rust preventive pigments, viscosity modifiers, preservatives, antifungal agents, antibacterial agents, coupling agents, deodorants Examples thereof include foaming agents, anti-settling agents, anti-skinning agents, polymerization inhibitors, leveling agents, thixotropic agents, color separation preventing agents and matting agents. These additives can be used alone or in combination of two or more.

The proportion of these additives is, for example, 0.1 to 50 parts by mass, preferably 0.5 to 30 parts by mass, more preferably 1 to 10 parts by mass (particularly 1.5 to 100 parts by mass) with respect to 100 parts by mass of the biorepellent agent. 5 parts by mass).

The antifouling paint of the present invention can be applied by a conventional method depending on the application, and may be applied (coated) using, for example, an air spray, an airless spray, a roll coater, a brush. The average thickness of the coating film (dry coating film) is not particularly limited, and may be, for example, 1 to 500 μm, preferably 10 to 400 μm, and more preferably 50 to 300 μm.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The details of the sample used are as follows.

Polysilane: "Polymethylphenylsilane (OGSOL SI-10-40)" manufactured by Osaka Gas Chemicals Co., Ltd. (weight average molecular weight: 700, number average molecular weight: 620)
Bacillus subtilis: Bacillus subtilis strain LB agar medium: Ultrapure water (milli Q water) as a solvent, high polypeptone (manufactured by Nippon Pharmaceutical Co., Ltd.) 10 g/liter, dried yeast extract (manufactured by Nacalai Tesque KK) 5 g/liter Medium containing 5 g/liter of sodium chloride (manufactured by Nacalai Tesque, Inc.) and 10 g/liter of purified agar powder (manufactured by Nacalai Tesque, Inc.) Commercial antifouling paint: Dainippon Paint Co., Ltd. “Sea Blue Ace King” ".

Example 1
To a 50 ml centrifuge tube filled with 30 ml of phosphate buffered saline, a preculture liquid of Bacillus subtilis was added so as to be 0.1% by volume in the physiological saline, and a live cell of phosphate buffered saline was added. The number was counted (initial viable cell count). A test piece in which polysilane was applied to one surface of a slide glass (72 mm×26 mm) was immersed in a phosphate buffered saline containing a preculture solution, and then allowed to stand for 1 day or 2 days. The results of measuring the viable cell count of saline are shown in Table 1.

The test piece that had been allowed to stand for 2 days was taken out from the centrifuge tube, drained, and then washed with 40 ml of sterile ultrapure water. The polysilane-coated surface of the test piece that had been drained after washing was pressed against the LB agar medium, and the contact state was maintained for 1 hour. After removing the test piece from the medium, the LB agar medium was cultured at 37° C. for 24 hours, and the colonies formed on the medium were observed. A photograph of the colony is shown in FIG.

Comparative Example 1
The culture test of Bacillus subtilis was carried out in the same manner as in Example 1 without applying polysilane to the slide glass, the viable cell count was measured, and colonies on the medium were observed. The results of measuring the viable cell count are shown in Table 1, and a photograph of the colony is shown in FIG.

As is clear from the results of Table 1 and FIGS. 1 and 2, in comparison with Comparative Example 1, Example 1 was able to inhibit the growth of Bacillus subtilis and also had an effect of inhibiting adhesion.

Example 2
An antifouling composition was prepared by adding and mixing polysilane to a commercially available antifouling paint so that the ratio of the polysilane was 20 parts by mass with respect to 80 parts by mass of the antifouling agent. After applying this antifouling composition to one surface of a polycarbonate plate, 150 juvenile pearl oysters were placed on the application surface and left still in seawater for 90 minutes. After standing for 90 minutes, the polycarbonate plate was taken out of seawater, and the number of pearl oysters attached to the polycarbonate plate was measured. As a result, the number of pearl oysters attached was 6.

Comparative example 2
As the antifouling composition, a commercially available antifouling paint was used without adding polysilane, and the adhesion state of the pearl oyster was tested in the same manner as in Example 2 except that the antifouling composition was used as it was. The number was 11.

From the results of Example 2 and Comparative Example 2, the adhesion rate of the pearl oyster was 7.3% before the immersion in Comparative Example 2, whereas it was reduced to 4% in Example 2, and The anti-adhesion effect was observed.

The biorepellent agent of the present invention has a repellent action against various organisms such as aquatic organisms and microorganisms, so various insects, insecticides, herbicides, sterilization, antibacterial applications, harmful organisms, For example, shellfish (barnacles, mussels, blue mussels, mussels, pearl oysters, etc.), polychaetes (maggots, etc.), moss worms (Chironomidae, etc.), ascidians, hydroids, algae (Aonori, Aosa), It can be used as an additive to repel mold and bacteria (such as Bacillus subtilis). In particular, polysilane has a releasability in addition to the biological repellent effect, so that it not only repels the living organisms, but also physically suppresses the attachment of the living organisms to the member, and therefore, as a stainproofing agent. Especially suitable. Therefore, as an antifouling paint containing the biorepellent agent of the present invention as an additive, the organism itself, or slime produced due to bacteria or the like is used to prevent adhesion to a submerged member or molded body. It can be used as a soiling agent.

The antifouling paint of the present invention is various members or molded bodies that come into contact with water such as fresh water or seawater, for example, hulls such as ship bottoms, floating bodies such as buoys, bridges and jetties, support parts in structures such as piers or It can be used as a coating for coating dipping parts, cooling pipes, flow path forming members such as intake pipes, fishing gear such as fixed nets, marine observation equipment, ropes, and the like.

Claims (9)

Biological repellent composed of polysilane. The biorepellent agent according to claim 1, wherein the polysilane has at least one structural unit among the structural units represented by the following formulas (1) and (2).
(In the formula, R ^{1 to} R ³ are the same or different and represent a hydrogen atom, a hydroxyl group, an organic group or a silyl group.) The biorepellent agent according to claim 1 or 2, wherein the polysilane is a polyalkylarylsilane having a weight average molecular weight of 100 to 10,000. A method of using the biorepellant according to any one of claims 1 to 3 for repelling pests. The method according to claim 4, wherein the pests are aquatic organisms and/or microorganisms. A method of using the biorepellent agent according to any one of claims 1 to 3 for preventing aquatic organisms from adhering to the surface of a member in water. The method according to claim 6, wherein the surface of the submerged member is the bottom of the ship. An antifouling paint containing the biorepellent agent according to claim 1. The antifouling paint according to claim 8, which is a ship bottom coating agent.