WO1987007476A1

WO1987007476A1 - Composite material and artificial bait

Info

Publication number: WO1987007476A1
Application number: PCT/US1987/001307
Authority: WO
Inventors: William E. S. Carr; Charles L. Beatty
Original assignee: University of Florida
Current assignee: University of Florida
Priority date: 1986-06-11
Filing date: 1987-06-10
Publication date: 1987-12-17
Anticipated expiration: 1988-12-11
Also published as: EP0268675A1; DK64588A; DK64588D0

Abstract

A composite artificial bait material comprising a foamed plastic (12) attached to a coating (10) containing an attractant for fish, the foamed plastic (12) being insoluble in but rendered soft when immersed in water and the coating (10) comprising a suspension of the attractant in a hydrophilic, water-insoluble matrix which releases the attractant upon immersion upon water.

Description

COMPOSITE MATERIAL AND ARTIFICIAL BAIT

BACKGROUND OF THE INVENTION Related Applications This is a continuation-in-part of application serial No. 872834, filed June 11, 1986. Field of the Invention

The present invention relates to artificial bait for aquatic animal species. Prior Art

The present invention relates to an artificial bait particularly adapted for fishing in both fresh and sea water.

Artificial baits have been proposed heretofore comprising absorbent materials which have been soaked in a liquid fish attractant. Generally, the attractant-soaked material is incorporated in an artificial lure which depends for the attraction of fish upon the physical shape of the lure as well as the chemical characteristics of the attractant.

Thus, U.S. Pat. No. 1,393,617, discloses the inclusion of a fish oil soaked cotton swab in an artificial structure containing a hole through which the fish oil escapes upon immersion in water. U.S. Pat. No. 2,826,853 describes an artificial fish lure which contains a strip of chamois soaked with a fish attracting liquid such as anise, fish oil, etc.

U.S. Pat. No. 2,979,778 describes an artificial fishing lure constructed of rigid plastic in the shape of a natural fish prey having incorporated therein a fish attractant which is capable of migration through the plastic for progressive release at its surface.

U.S. Pat. No. 2,797,519 also describes an artificial lure which contains a porous resilient plastic or sponge rubber surface capable of absorbing fish attractant for subsequent release upon immersion in water.

U.S. Pat. No. 4,245,420 discloses and claims an Artificial Bait for Aquatic Species which generally comprises a semi-rigid, flexible, water insoluble, hydrophilic matrix which is permeable by diffusion, to the passage of an attractant incorporated in the hydrophilic matrix and which is capable of releasing the attractant upon immersion In an aqueous medium. In general, the patent discloses a hydrophilic matrix composition consisting of gelatin and water or gelatin, water and glycerin.

U.S. Pat. No. 2,874,048, Walldov, is directed to an Aquatic Species Synthetic Bait having a composition very similar to that disclosed in U.S. Pat. No. 4,245,420, and which, according to the patentee, is slowly soluble in water to simulate bleeding of the bait.

U.S. Pat. No. 4,463,018 discloses a semi-rigid, flexible, water-insoluble, hydrophilic matrix comprising the solid or semi-solid phase formed from a colloidal solution of a liquid, preferably water, in a macromolecular composition including gelatin, agar, locust bean gum, Celufil (a partially hydrolyzed cellulose manufactured by U.S. Biochemical Corp.) and glycerol prepared at a temperature not exceeding 100°C. The hydrophilic, gel-like solid phases of such colloidal solution are particularly adapted for the formation of artificial fish baits having the texture and consistency of common and natural fish prey. U.S. Pat. No. 3,410,689 discloses a fish bait comprising a foamed plastic impregnated with a fish attractant which "disjoins" upon immersion In water and releases the attractant.

U.S. Pat. No. 4,202,905 discloses the use of a foamed polyurethane as a carrier for a luminous fish attractant in an artificial bait. All of the prior art artificial bait compositions and devices have certain advantages, however, to date none combine all of the qualities required of a commercially acceptable artificial bait. Thus, the fishing industry requires a bait which will withstand tearing and rupturing upon contact with aqueous media and aquatic animal species but which will be capable of releasing the contained attractant over long periods of time. Moreover, the bait must present the necessary physical, tactile and gustatory appearance to the target aquatic species to be acceptable and attractive. Also, the bait must be sufficiently heat resistant and otherwise stable under the adverse conditions traditionally prevalent at fishing sites to provide a long shelf-life. It is an object of the present invention to provide a composite material particularly adapted for the preparation of artificial bait for aquatic animal species which avoids the shortcomings of the presently available baits and possesses the above-described advantages.

SUMMARY OF THE INVENTION

The above and other objects are provided by the present invention, one embodiment of which is a composite material comprising a foamed plastic having integrally attached to a major surface thereof a coating containing an attractant for an aquatic animal species (e.g., fish), (1) the foamed plastic being substantially insoluble in, but rendered relatively soft and pliable when immersed in, an aqueous medium and (2) the coating comprising a suspension of the attractant in a hydrophilic, water insoluble matrix comprising a hydrophilic colloid and a humectant suspended in a polymer, the matrix being capable of releasing said attractant upon immersion in an aqueous medium at a predetermined and controlled rate over a prolonged period of time. The above and other objects are also realized by another embodiment of the invention which comprises an artificial bait composition or device constructed at least In part from the above-described composite material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 6 are fragmentary perspective views of the composite material of the invention. FIG. 2 is a perspective view of an artificial bait of the invention constructed from the composite material.

FIGS. 3A, 3B and 3C are perspective views of artificial baits of the invention constructed in part from the composite material.

FIGS. 4A, 4B and 5 are graphic depictions of the attractant release characteristics of the composite material and bait of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention describes a bait having a surface coating of a feeding stimulant for fish bonded onto a layer of reticulated polyurethane foam which is in turn bonded onto a tear-resistant backing material (FIG. 1). The foam layer does not disjoin when submerged In the water, but instead remains intact for many hours or even days. The foam layer can, however, be torn from the hook when fish feed on it. Hence, a tear-resistant backing sheet is bonded onto the foam to greatly increase the tear strength of the bait, thereby Increasing both the retention time on the hook and the utility of the product for a broad range of applications. The crux of the invention resides in the surface coating of stimulant bonded onto the foam which provides a bait with properties far superior to that of a bait in which stimulant is incorporated directly into the foam as an integral part thereof. In the artificial bait compositions of U.S.

Patents Nos. 4,463,018 and 4,245,420, the hydrophilic matrix suspension containing the attractant was prepared in such a manner to provide a gel-like structure having flesh-like textures and consistencies of common aquatic animal species prey even prior to submersion in water.

In the compositions of the present invention, the hydrophilic matrix, although containing some of the ingredients found in the gels of the above-noted prior patents, is in the form of a non-gel-like coating which possesses the unique property of being capable of releasing the contained attractant at a higher rate, and for longer periods of time than the baits heretofore available.

The desirable texture and consistency are provided for the most part by the plastic foam which, upon immersion in aqueous media, is rendered relatively soft and pliable. Referring to the drawings, the composite material of the invention Is depicted in FIG. 1 wherein the attractant releasing surface coat 10 is integrally attached or bonded to foamed plastic layer 12. Optimally, a tearor rupture-resistant backing layer 14 is integrally associated with the side of the foamed plastic layer opposite that coated with the surface layer to provide additionally structured integrity and toughness. Finally, as depicted in Fig. 6, a water-insoluble film 16 which limits access to the coating 10 of water may be applied.

The surface coat is preferably prepared by mixing a hydrophilic colloid with an aqueous emulsion of a suitable film forming polymer and the attractant. If the surface coating shows a tendency to crack when dried, the flexibility of the dried coat can be increased by adding a humectant such as glycerol or propylene glycol to the other surface coat components. It is also preferred to include preservative agent in the surface coating composition such as potassium sorbate, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), propyl gallate, citric acid, or mixtures thereof, etc.

The surface coating composition is prepared as a viscous liquid that is applied to the surface of the plastic foam. The surface coat may be dried almost entirely on the outer foam surface or tamped or rolled into the interstices and reticulations of the foam so that some of the coating is ultimately dried both on the outer foam surface and also within some of the inner cell spaces of the foam. Alternatively, the liquid surface coat material may be mixed with the surface layer of the pre-foamed plastic mixture while the foaming reaction is in progress. The latter process leaves some of the coating material both on the outer surface layer and within the inner cell spaces of the foamed plastic. Alternatively, the inner cell spaces of a pre-formed foam may be substantially completely filled with the liquid surface coat material by compressing (squeezing) the foam while it is submerged in the liquid material . Compression and relaxation of the submerged foam replaces the air in the foam cells with the liquid material. The latter process fills inner cell spaces with the liquid, and, following the drying process, provides a product in which both the inner cells and the surface of the foam are coated with an attractant-laden coating. The rate of release of stimulant from the surface coat can be controlled by varying one or more of the following parameters: (1) concentration of stimulant (2) manner of application of coating to the foam (3) concentrations and relative proportions of hydrophilic colloid, polymer and, optimally, humectant, and (4) coating or dipping the dried product either partially or completely in a suitable aqueous polymer emulsion to provide a protective film that limits , i.e., delays the access of water to the attractant-laden surface coat.

After the surface coat is applied, it is dried to produce a thin, soft, flexible coating that is tightly bonded to the foam by the combined adhesive properties of both the hydrophilic colloid and the polymer. The dried, stimulant-rich surface coat, and the foam beneath and around it, is stable to prolonged storage at room temperature. The dried coat quickly hydrates and softens In the water to yield a soft, slick, "slimy", outer surface layer that feels much like moist skin while releasing stimulant.

The foam layer preferably comprises a foamed, or foamable, hydrophilic polyurethane polymer (e.g., Hypol FHP 2000, W.R. Grace & Co.) which will not disjoin or disintegrate in aqueous media, water, a feeding stimulant and, if desired, preservatives. If a feeding stimulant is used in the foam layer, the stimulant plus preservatives are mixed or blended with water prior to the initiation of the foaming reaction. After the foaming reaction is completed, much of the stimulant thus incorporated into the foam layer is not rapidly released into the water when the bait is immersed (see FIG. 4B). Hence, the combined effect of providing a surface coat from which stimulant is rapidly released, plus a non-disjoining foam layer from which stimulant is not readily released, is to provide a bait with a fast, yet controlled, "chumming" effect from the surface coat, together with a reservoir of unreleased, tastant substances that are retained in the foam layer (and surface coat) which provide gustatory stimulation once the bait is nibbled or taken into a fish's mouth.

Following the completion of the drying of the foam layer and surface coat, a dehydrated product is obtained that has great stability and is ideal for storage in a sealed container without refrigeration. Upon immersion in water, the spongelike properties of the foam cause it to promptly swell and soften, and together with the soft, slick surface coat, provide a bait that has extremely fleshlike tactile and chemically attractive properties. The bait both releases chemoattractive odorant molecules into the water and retains tastant molecules in and on the bait that stimulates additional feeding behavior when the fish physically contacts the bait.

To provide additional toughess and wear resistance, a backing material, such as a polyurethane or other suitable polymer preferably about 3 mil in thickness, is bonded onto the foam. This layer provides a thin, flexible outer skin that imparts major tear resistance to the bait thereby prolonging its duration on the hook. The backing material may be bonded to the foam layer with an adhesive polymer emulsion (e.g., Helastic polyurethane

WC-6512) that is partially dried onto the backing material prior to pouring the reactive foaming components over it. Following the final drying process, the backing material is securely bonded to the foam layer. Alternatively, the backing material can be bonded onto the preformed foam layer with heat, solvents, ultrasonics or other adhesives. Alternatively, when certain backing materials are employed (e.g., certain extruded polyurethane sheets), a suitable bond forms between the resultant foam and the backing material itself without the necessity for employing any additional adhesive material.

Alternatively, the backing layer may be formed integrally with the foamed plastic during the foaming operation as a substantially non-foamed "skin".

Polyurethane or other foamable thermoplastic elastomer precursors that have either (1) a gas such as fluorocarbon nitrogen, etc., or (2) a decomposable molecule such as sodium bicarbonate, azo compounds, etc., are admixed to form a foamable extrudate. By controlling the sheet die temperature during the extrusion, it is possible to form a non-foamed "skin" on the foamed plastic. The skin provides a tear-resistant cover that negates the need for affixing a separate, tear-resistant backing material. For a single skinned sheet or unskinned open cell or reticulated foam, the attractant solution may be added to the foam by passing the foam sheet through a pair of compression rollers beneath the surface of the attractant solution. The rollers will expel the air and allow attractant to fill the open foam cells. An additional layer of attractant/polymer mixture (or chumming layer) may be coated on the unskinned surface.

The foam sheet that is skinned on both surfaces can be sliced with a knife to form two single skinned foam sheets.

Additional prolongation of the effective lifetime of the bait can be obtained by further coating the entire product with a thin film of a water insoluble material such as a polyurethane. This film is conveniently applied as an aqueous dispersion of the polymer (e.g . , Helastic WC-6512, Wilmington Chemical Corp.). This filmamay be applied by cutting the dried product into bait-size portions, and then dipping, spraying or painting the portions with the polymer emulsion. The surface film may be dried by hanging the product in an oven at 80°C for about 15-minutes, or at room temperature (about 22°C) for about two days. The surface film can be applied to completely cover the bait for a maximum diminution in stimulant release, and subsequent prolongation of stimulant retention for several hours. Alternatively, the film can be applied to only partially cover the bait to provide a range of profiles of stimulant release, and bait lifetimes, that are intermediate between those of the completely coated or completely uncoated product.

A great variety of fish, feeding stimulants can be incorporated into both the surface coat and the foam layer of the bait. Any stimulant in either liquid or solid (e.g., meal, crystalline chemicals) form can be used.

Attractants can be prepared from natural baits or fishery wastes (e.g., shrimp heads, fish heads, carcasses) and underutilized species by liquification and heat treatment to Inactivate hydrolytic enzymes. Also, liquified or solid wastes can be dried and ground to a meal for incorporation into the baits. Useful synthetic stimulants are described in the following publications.

Carr and Chaney, Chemical stimulation of feeding behavior in the pinfish, Lagodon rhomboides; characterization and identification of stimulatory substances in a shrimp extract. Comp. Biochem. Physiol. 54A: 437-441 (1976); Carr, Blumenthal and Netherton. Chemoreception in the pigfish, Orthopristis chrysopterus: the contribution of amino acids and betaine to stimulation of feeding behavior by various extracts. Comp. Biochem. Physiol. 58A; 69-73 (1977); Carr and Derby. Behavorial chemoattractants for the shrimp, Palaemonetes pugio: identification of active components in food extracts and evidence of synergistic mixture interactions. Chem. Senses 11: 49-64 (1986). EXAMPLE 1

The various components of the composite material may be combined in the following proportions to produce the compositions of the invention.

Range of amounts : COMPONENT g/100 g of starting material

Surface coat

Carboxymethylcellulose .5 - 2.0

Humectant (e.g., glycerol) 0 - 8.0

Emulsion polymer 0 - 30

Water 54- 93

Preservatives, e.g.,

Potassium sorbate .05 - 1.0

Antioxidants* .001 - .1

Stimulant

Synthetic 5 - 20

Natural (Shrimp,, fish, etc.) 5 - 44

Foam layer

Foamable plastic, e.g., polyurethane pre-polymer

(FHP 2000) 25 - 60

Water 40 - 55

Preservatives

Potassium sorbate .05 - 1.0

Antioxidants* .001 - .1

Stimulant

Synthetic 1 - 15

Natural (Shrimp, fish, etc.) 10 - 33

Meal 1 - 21

* Typical composition of antioxidant 2 g butylated hydroxytoluene, 2 g butylated hydroxy- anisole, 1 g propyl gallate, 1 g citric acid, and 4 g propylene glycol. Dissolved in 10 ml ethanol.

The invention is illustrated by the following non-limiting examples : EXAMPLE 1

Shrimp Flavored Bait A. Surface Coat 1) Stimulant - whole shrimp or shrimp heads. a. An enzyme-inactivated slurry of shrimp is prepared and centrifuged to obtain a particle-free supernatant containing feeding stimulants. b. In the stated order are added to a mixing vessel: 40 g of above supernatant

0.35 g potassium sorbate 0.08 ml antioxidant solution (see above) 0.6 g carboxymethylcellulose mixed with 1.5 g glycerol 2 g Helasic WC-6512 (polyurethane).

During addition of each ingredient, continuous stirring is necessary to insure proper mixing. After addition of carboxymethyl cellulose, time is allowed for complete hydration and viscosity increase to occur before adding Helasic.

2) Stimulant - synthetic shrimp components. a. Synthetic attractant is dissolved in water to a concentration of 15% (w/w) and the above example repeated with 40 g of the synthetic attractant. B. Foam layer. In the stated order are combined in a mixing vessel:

73 g enzyme-Inactivated shrimp slurry 0.5 g potassium sorbate 0.15 ml antioxidant.

The above are combined with 26 g Hypol FHP 2000 foamable polyurethane prepolymer, mixed vigorously with a stirring motor, and poured over a tear-resistant sheet (see below) in a 35 in² mold. C. Preparation of tear-resistant sheet. One part Helastic WC-6512 (polyurethane adhesive) is diluted with 3 parts water, spread as a thin film over a sheet of Tuftane 800 (polyurethane elastomer) in a mold, and dried to a tacky consistency with a heat lamp.

D. Addition of surface coat to foam. After 10 minutes, when the reticulated foam has developed, the surface coat

(1 or 2 above) is poured and spread onto the foam layer, and gently tamped or rolled Into the foam surface.

E. Drying. The surface coat/foam combination is dried for several hours at 80°C in a drying oven until all free water is gone thereby producing a composite from which artificial baits are cut and assembled in desired shapes and sizes.

EXAMPLE 2

Cigar Minnow (=Baitfish) Flavored Bait

A. Surface Coat - A supernatant is prepared by centrifugation and evaporative concentration of an enzyme-inactivated slurry of cigar minnow (Decapterus sp). In the stated order are added to a mixing vessel: 53 g supernatant of cigar minnow

0.44 g potassium sorbate

0.11 ml antioxidant (see above)

0.8 g carboxymethyl cellulose mixed with 2 g glycerol

2.7 g Helastic WC-6512 (polyurethane) The mixture is processed as in Example 1.

B. Foam layer - In the stated order are added to a suitable vessel:

67 g supernatant 0.5 g potassium sorbate 0.14 ml antioxidant (see above).

The above are added to 33.5 g of FHP 2000 prepolymer, mixed vigorously and poured over a tear-resistant sheet as in Example 1 above.

Steps C, D and E are repeated as in Example 1 above. The resulting composite is cut and assembled to form artificial baits of desired shapes and sizes.

EXAMPLE 3

The following is an example of a product without a humectant or an emulsion polymer in the surface coat, and without adhesive material for bonding backing sheet to foam, and with a final dip in emulsion polymer to prolong lifetime of bait. A. Surface Coat

1) Stimulant - synthetic shrimp components. a) Synthetic attractant is dissolved in water to a concentration of 15% (w/w). b) In the stated order are added to a mixing vessel: 100 g of the above synthetic attractant 0.5 g potassium sorbate 0.2 ml antioxidant solution 1 g carboxymethylcellulose B. Foam Layer. The following are combined in a mixing vessel: 120 g shrimp slurry

0.33 g potassium sorbate

The above are combined with 60 g Hypol FHP 2000 foamable polyurethane prepolymer, mixed vigorously with a stirring motor, and poured over a sheet of Tuftane TF-800 (extruded polyurethane sheet, Lords Corp., Erie, Pa., without adhesive) in a 91 in² mold.

C. Addition of surface coat to foam. The developed reticulated foam is dried in a drying oven at 80°C for approximately 1 hr. The surface coat is then poured, spread, and tamped into the foam surface.

D. Drying. The surface coat/foam combination is dried for several hours at 80°C in a drying oven until all free water is gone. E. Addition of surface film to prolong lifetime of bait. The dried product resulting from D. above is cut into portions of the desired size. Each portion is dipped into

Helastic WC-6512 such that 75-80% of the outer surface is covered with the aqueous polymer dispersion. The dipped baits are hung at room temperature and permitted to dry over a ca. 2-day period; alternatively, they can be dried in a ca. 15-minute period in a drying oven at 80°C. The dipped portion of the dried product is thus provided with a thin, strong, flexible film of polyurethane.

The hydrophilic colloid may be a cellulose gum, carboxymethylcellulose and salts thereof, natural and synthetic gums, proteins, polymers, algin, agar.

The hydrophilic colloids listed below may be substituted for carboxymethylcellulose and used to prepare surface coats as described above. Hydrophilic colloid g/ 100g of aqueous attractant

Guar gum 0.5, 1.0, or 2.0

Locust bean gum 0.25, 0.5, 1.0, 1.5, or 2.0

Locust beam gum (1%) plus

Helastic WC-6512 Helastic = 5, 10, or 20 Xanthan + locust bean gum

+ guar gum (Kelco*GFS) 0.5, 1.0, or 2.0

Kelco* K1B109F 0.5, 1.0 or 2.0

Tragacanth gum 0.5, 1.0, or 2.0

Carageenan gum 0.5, 1.0, or 2.0 Karaya gum 0.5, 1.0, or 2.0

Acacia gum 0.5, 1.0, or 2.0

Algin (Kelco* Kelgin MV) 0.5, 1.0, or 2.0

Algin (Kelco* Keltone) 0.5, 1.0, or 2.0

Algin (Kelco* Keltone) 2.0 washed with Ca⁺+ Agar (dissolved in 95°C water) 0.5, 1.0, or 2.0

Casein 5.0

Casein + carbomethyl- cellulose 5.0 + 1.5

Carboxymethylcellulose (CMC) 1.5 CMC washed with Al⁺3 CMC (1%) plus Helastic WC-6512 Helastic = 5, 10 or 20

*Kelco = Division of Merck and Co., Rahway, N.J. The following table sets forth alternatives and equivalents for the other components of the composition.

Component Alternative

Hydrophilic colloid Carboxymethyl cellulose, gums and thickening agents such as quar, locust bean, tragacanth, karaya, etc.

Humectant Glycerol, propylene glycol

Foamable plastic Polyurethane and other foamable polymers to which surface coat may be bonded, e.g., cellulose acetate, polyethylene, polypropylene, polyvinyl chloride

Emulsion polymer Styrene butadiene copolymers, poly- urethanes, acrylics, etc.

FIGS. 4A and 4B graphically depict the attractant release characteristics of the baits prepared above. Two 10-g portions of the same polyurethane foam were prepared to differ only in the following regard: One portion has 500 mg of a stimulant incorporated Into a surface coating as described in Example 1, whereas the second portion has 500 mg of the same stimulant incorporated only and directly into the foam. The material with the stimulant in the surface coat displays the following superior qualities that are critical to the effectiveness of a bait: (1) During the first 20 minutes in the water, the surface-coated material releases stimulant at a rate (mg stimulant/g of bait/min) that ranges from 2- to 5.5-times greater than the rate realized during the same time period by the material with stimulant incorporated into the foam itself, (see FIG. 4A). (2) During the first 30 minutes in the water, the surface-coated material releases about 87% (435 mg) of the total stimulant it contains whereas only about 30% (150 mg) of the total stimulant is released by the material with the stimulant in the foam layer (see FIG. 4B). (3) During the entire 30 minutes in the water, the surface-coated material retains a soft, slimy texture that is absent from the uncoated material. This soft, slimy texture contributes a significant tactile and gustatory property that is important in the acceptability of the bait by fish. Field tests showed that baits with a surface coating of feeding stimulant consistently outperformed those with stimulant only in the foam. As shown in FIG. 5, a bait with a surface coating of stimulant prepared as described in Example I, releases stimulant at a much greater rate, and for a longer duration, than even an exceptional natural bait such as fresh, peeled shrimp.

Claims

CLAIMS :

1. A composite material comprising a foamed plastic having integrally attached to a major surface thereof a coating containing an attractant for an aquatic animal species, (1) said foamed plastic being substantially insoluble in but rendered relatively soft and pliable when immersed in, an aqueous medium and (2) said coating comprising a suspension of said attractant in a hydrophilic, water insoluble matrix comprising a hydrophilic colloid suspended in a polymer, said matrix being capable of releasing said attractant upon immersion in an aqueous medium at a predetermined and controlled rate over a prolonged period of time.

2. The composite material of claim 1 wherein a major surface of said foamed plastic other than that containing said coating has integrally attached thereto a backing layer which is resistant to tearing and being capable of providing structural integrity to said artificial bait upon contact with said aquatic species.

3. The composite material of claim 1 or 2 wherein said foamed plastic has incorporated therein said attractant and said foamed plastic is capable of releasing said attractant upon immersion in an aqueous medium at surfaces thereof exposed to said aqueous medium or by passage through said coating.

4. The composite material of claim 1 or 2 wherein said foamed plastic is selected from the group consisting of polyurethanes, cellulose acetate, polyethylene, polypropylene and polyvinyl chloride.

5. The composite material of claim 1 or 2 wherein said foamed plastic is a polyurethane.

6. The composite material of claim 1 or 2 wherein said attractant is a substance which stimulates the instinctive feeding behavior of said aquatic animal species.

7. The composite material of claim 1 or 2 wherein said hydrophilic colloid is selected from the group consisting of cellulose gums, carboxymethylcellulose and salts thereof, natural and synthetic gums, proteins, polymers, algin, agar.

8. The composite material of claim I or 2 wherein said humectant is selected from the group consisting of glycerol and propylene glycol.

9. The composite material of claim 1 or 2 wherein said polymer is a polyurethane, a styrene-butadiene copolymer or an acrylic polymer or copolymer.

10. The composite material of claim 2 wherein said backing layer is adhesively bonded to said major surface of said foamed plastic.

11. The composite material of claim 2 wherein said backing layer comprises a substantially unfoamed layer of said plastic.

12. The composite material of claim 1 or 2 wherein said water insoluble matrix includes a humectant.

13. An artificial bait constructed at least in part from the composite material of claim 1 or 2.

14. An artificial bait constructed at least In part from the composite material of claim 3.

15. A composite material of claim 1 or 2 wherein said coating is coated with a water-insoluble film which limits access thereto of water.