WO1999053755A1

WO1999053755A1 - Horticultural compositions comprising amphoteric polymers and methods of utilizing the horticultural compositions

Info

Publication number: WO1999053755A1
Application number: PCT/US1999/008839
Authority: WO
Inventors: Joseph Thomas Ippoliti
Original assignee: Joseph Thomas Ippoliti
Priority date: 1998-04-22
Filing date: 1999-04-22
Publication date: 1999-10-28
Also published as: AU3661799A

Abstract

The present invention provides horticultural compositions comprising at least one hydrophilic amphoteric polymer that absorbs water supplied by humidity, precipitation or irrigation, and releases the absorbed water to a horticulturally viable substrate or growing medium upon demand. Additionally, methods of horticulture are provided for utilizing the horticultural compositions that places the horticultural compositions in close proximity with the horticulturally viable substrate such that the viability and growth of the horticulturally viable substrate is enhanced by the readily available water supplied by the horticultural compositions. By virtue of the hydrophilic nature of the amphoteric polymers, the horticultural compositions and methods of the present invention utilize supplied water in an exceptionnally efficient manner, thus reducing the costs associated with irrigation and irrigation equipment.

Description

Horticultural Compositions

Comprising Amphoteric Polymers and Methods of

Utilizing the Horticultural Compositions FIELD OF THE INVENTION

The present invention relates to horticultural compositions for enhancing water availability to a plant and thus, the growth of the plant. More specifically, the present invention relates to horticultural compositions comprising hydrophilic amphoteric polymers. When hydrated and applied or placed proximal to a horticulturally viable substrate, such as seeds, a seedling or a growing plant, the horticultural compositions comprising the amphoteric polymers provide a readily available supply of water to the substrate. Additionally, the horticultural compositions can be utilized as carriers for plant nutrients, or other horticulturally beneficial agents. When used in this manner, the horticultural compositions of the present invention provide the advantage of controllably delivering nutrients and/or other agents to the substrate.

BACKGROUND OF THE INVENTION

Historically, horticultural and agricultural industries have been irrigation intensive. In order to germinate, emerge from the soil and undergo optimum growth, plants require large amounts of water. In many areas, or in greenhouse applications, sufficient water is not provided by rainfall, and thus, irrigation is required to provide seeds, seedlings and growing plants with an adequate water supply. However, even when an adequate amount of water is initially supplied either by irrigation or precipitation, only a small fraction of the supplied water remains available for use by the plants, due to such factors as soil drainage and evaporation. Thus, not only the amount of water supplied, but also, the frequency at which the water is supplied, are important considerations in horticultural or agricultural industries. However, the frequent irrigation necessary to supply plants with adequate water for optimum growth is expensive not only because of the cost of the water, but also because of the cost of irrigation equipment and the associated cost of the labor required to utilize and maintain the irrigation equipment.

Hydrophilic polymers were introduced for agricultural and horticultural use in the 1970's. Since their introduction, such polymers have been incorporated into horticultural media and methods in order to increase the amount of supplied water that remains available to plants and/or to deliver nutrients. For example, hydrophilic polymers have been applied topically to growing plants, mixed with seeds for gel or hydroseeding applications, and incorporated into conventional growing media. When the growing medium, seeds or plants are subsequently irrigated or precipitated upon, the polymers absorb and store the water, and thus, less of the water supplied is lost to evaporation and soil drainage. As a result, a greater percentage of the supplied water remains available to the seeds or plant, and the intervals between required irrigation may be lengthened accordingly. Utilization of hydrophilic polymers in agricultural and horticultural applications thus increases the efficiency of water usage. As a result, these polymers have become increasingly important in horticultural/agricultural applications. However, as important as these polymers are currently, they are likely to become even more important as water use restrictions become more prevalent and restrictive. In fact, it is expected that the importance of hydrophilic polymers in agricultural applications will increase steadily in coming years.

One class of hydrophilic polymers that has been used in agricultural applications is the class of polyacrylamides. For use in agricultural applications, these polymers are generally provided in the shape of small granules which are incorporated into the desired growing medium. Polyacrylamides are capable of absorbing many times their weight in water and expand greatly when hydrated. Due to their capacity to expand upon hydration and to shrink during dry down, polyacrylamides also provide an aeration factor to the root zone when incorporated into soil. However, polyacrylamides exhibit only limited compatibility with fertilizers and fertilizer salts. Thus, upon irrigation or precipitation, the nutrients provided by fertilizers may be washed away rather than being beneficially absorbed by the polymers along with water. Finally, polyacrylamides are nonionic and thus, interact with water primarily by hydrogen bonding, a weak interaction which limits the hydrophilicity of these polymers.

Thus, there is a need for improved hydrophilic polymers that may be used in agricultural/horticultural applications to retain supplied water in a source where it is readily available upon demand of a seed, seedling, or plant. Desirably, such polymers would be compatible with fertilizers, such that the fertilizers are attracted to the polymer, absorbed and released along with the absorbed water. It is additionally desired that the hydrophilic polymers identified for agricultural or horticultural use would be comprised of non-toxic monomers. SUMMARY OF THE INVENTION According to the present invention, the above objectives and other objectives apparent to those skilled in the art upon reading this disclosure are attained by the present invention which is drawn to horticultural compositions and methods for increasing the quantity of supplied water and/or nutrients that are available to a horticulturally viable substrate during at least a portion of the life cycle of the substrate. More specifically, it is an object of the present invention to provide horticultural compositions comprising amphoteric polymers that absorb water supplied by humidity, precipitation or irrigation, and release the absorbed water to a horticulturally viable substrate, or to a growing medium, upon demand. It is a further object of the present invention to provide methods for utilizing these horticultural compositions in functional proximity to a horticulturally viable substrate such that the viability and growth of the substrate is enhanced.

The present invention is based on the surprising discovery that amphoteric polymers, particularly those that are zwitterionic in the pH range in which the horticultural compositions will be used, can be beneficially exploited in horticultural applications to enhance the growth and viability of seeds, seedlings and plants. In particular, horticultural compositions of the present invention comprising such amphoteric polymers, and the methods of using them, utilize supplied water and/or nutrients in an exceptionally efficient manner, thus reducing the costs associated with irrigation and irrigation equipment. In one aspect, the present invention relates to horticultural compositions for promoting plant growth and viability comprising at least one amphoteric polymer having cationic functionality in a first pH range, zwitterionic functionality in a second pH range, and anionic functionality in a third pH range. The present invention also provides methods for utilizing the horticultural compositions of the present invention comprising the steps of providing a horticultural composition in accordance with the present invention and placing the horticultural composition in functional proximity to a horticulturally viable substrate.

In preferred embodiments, the horticultural compositions may beneficially comprise other components in order to make the horticultural compositions more readily usable and/or multifunctional. For example, the horticultural compositions may further beneficially comprise an effective amount of a nutrient such as a fertilizer, a micronutrient, a pesticide, a herbicide, a game repellent, a nematocide, a fungicide, a growth retardant, a germination promoter, combinations of these and the like.

Additionally, the horticultural compositions may beneficially comprise an amount of water or other suitable solvent sufficient to result in the horticultural compositions being sprayable, mixable, or coatable onto the desired substrate, e.g., at least one viable seed, a seedling or a plant. The horticultural compositions may coat only a portion of horticulturally viable substrate, i.e., a portion of a seed, or the roots, stems, leaves or petals of a seedling or plant, or alternatively, the horticultural compositions may coat substantially the entirety of the above ground and/or below ground portions of the horticulturally viable substrate. If the substrate is a seed, the coated seed may then be planted in a suitable growing medium using any desired planting technique, such as sowing, hydroseeding, gel-seeding, tilling into the soil, transplanting, and the like. As used herein, the term "nutrient" refers to an ingredient that may be topically applied onto a plant or incorporated into a growing medium in order to promote the growth and/or health and well-being of the plant. Examples include not only plant food, such as fertilizer salts, but also health and growth treatment agents of the type described below.

Horticultural compositions of the present invention may also be beneficially used as a component of a growing medium, e.g., a soil. In this embodiment of the invention, the horticultural compositions may be topically applied to the desired growing medium, may form substantially the entirety of the root supporting componentry of the growing medium along with optional ingredients such water and nutrients, or may be intermixed with other soil media in an amount effective to enhance the ability of the growing medium to use water and/or nutrients. A seed, seedling or plant may subsequently be planted in the growing medium of this invention, and the growing medium will then help to provide a readily available supply of water and/or nutrients to the seed, seedling or plant. The term "soil media" refers to root supporting media in which plants may grow. Examples of soil media include naturally occurring soils, mulch, potting soil, clay, "vermiculite" processed mineral, "perlite" processed mineral, compost, sand, gravel, scoria, pumice, foam, polymeric media including the amphoteric polymer of this invention, sawdust, peat moss, rockwool, combinations of these, and the like. As used herein, the term "mulch" is meant to indicate an organic fibrous material such as crushed peat, bark, leaves, straw, cellulose fibers, wood, paper pulp and the like. Additionally, as used herein the term "compost" is meant to indicate a mixture of substantially decayed organic matter, such as yard waste, food waste, animal waste, forest products, and the like, suitable for fertilizing plants.

The utility of the horticultural compositions of the present invention is not limited only to applications where the enhanced growth or long term viability

5 of plants is desired or intended. The horticultural compositions of the present invention may also be utilized to enhance the attractiveness and longevity of cut flower arrangements or the like. In this embodiment of the present invention, the horticultural compositions would simply be placed in functional proximity to the cut plants, i.e., coated onto stems, plants, roots, leaves, petals, etc. In this manner, the horticultural composition would help to provide a readily available supply of water, and optionally, nutrients, even during periods of low watering, such that the cut flowers and/or greens would remain attractive for a longer period of time than arrangements that are not in contact with horticultural compositions of the present invention.

The horticultural compositions of the present invention may be used in greenhouse, field, and landscape applications to increase the growth rate of plants, thereby providing earlier maturity. Additionally, in greenhouse applications, utilization of the horticultural compositions of the present invention can result in a greater realized shelf-life for containerized seedlings or plants, thus reducing the mortality traditionally experienced in these applications. In field applications, utilization of the horticultural compositions of the present invention can provide longer intervals between required irrigation, thereby reducing water costs, as well as the costs associated with operating, maintaining and repairing irrigation equipment. Finally, in retail applications involving the sale of plant cuttings, the horticultural compositions of the present invention may be used in the form of an aqueous composition that can be sprayed onto the cuttings to reduce the supplied water requirement of the arrangements and extend the length of time before the onset of wilting, all without detrimentally affecting the appearance of the cuttings. Thus, the horticultural compositions and methods of the present invention provide many advantages to the horticultural and/or agricultural practitioner. Additionally, the horticultural compositions of the present invention provide many advantages over the prior art horticultural compositions comprising polyacrylamides. First of all, the polymers of the present invention are ionic over a wide pH range, and thus, the interactions between polymers of the present invention and water involve both hydrogen bonding and ion-dipole forces. Thus, the inventive polymers have a significantly stronger affinity for water than polyacrylamides. Additionally, due to their high affinity for water, the amphoteric polymers of the present invention release the absorbed water at a slower rate than prior art horticultural compositions comprising polyacrylamides. As a result, the available supplied water is utilized more efficiently. In addition, because of their stronger ionic character, the horticultural compositions of the present invention are more compatible with fertilizers, i.e., nutrient salts, than the prior art polyacrylamide horticultural compositions.

A number of formulations are given throughout this specification. All percentages and ratios with respect to such formulations are on a weight basis unless otherwise indicated. Additionally, all references to molecular weight of polymeric materials are meant to indicate weight average molecular weight unless otherwise indicated.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other advantages of the present invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

Figure 1 is an illustration of a reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from a polymer having maleic anhydride functionality; Figure 2 is a specific application of the reaction scheme of Figure 1; Figure 3 is an illustration of a reaction scheme showing how another embodiment of an amphoteric polymer of the present invention is formed from vinyl monomers; and Figure 4 is an illustration of a reaction scheme showing how to make the tertiary amine functional vinyl monomer of Figure 3.

Figure 5 is an illustration of a reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from (meth)acrylic acid and a vinyl monomer having tertiary amine functionality;

Figures 6 A and 6B are an illustration of a two-step reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from maleic anhydride, a vinyl monomer having tertiary amine functionality, and an alcohol;

Figure 7 is an illustration of a reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from acrylic acid and 2-(dimethylamino)ethyl acrylate;

Figure 8 is an illustration of a reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from maleic anhydride and 2-(dimethylamino)ethyl acrylate;

Figure 9 is an illustration of a reaction scheme showing how one embodiment of an amphoteric polymer useful in the horticultural composition of the present invention is formed from maleic anhydride and 2-(dimethylamino)ethyl acrylate;

Figure 10 is a graph depicting the relationship between the concentration of a horticultural composition in accordance with the present invention and the emergence of grass seeds coated with such a horticultural composition;

Figure 11 is a graph depicting the relationship between the concentration of a horticultural composition in accordance with the present invention and the growth of grass seeds coated with such a horticultural composition in a 5 day period. DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED

EMBODIMENTS

The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.

As described herein, the present invention provides horticultural compositions comprising a hydrophilic amphoteric polymer, as well as methods of using the hydrophilic amphoteric polymer to manage the uptake, retention and release of water and other nutrients to horticulturally viable substrates during substrate growth. In certain embodiments of the invention, the amphoteric polymers may also be zwitterionic. As used herein, the term "amphoteric" is meant to indicate a material that can be either cationic, anionic, or both, depending on pH. Also, as used herein, the term "zwitterionic" refers to an amphoteric material that includes both cationic and anionic functionality concurrently.

The present invention is based upon the surprising discovery that hydrophilic amphoteric polymers of the present invention can be beneficially exploited in horticultural applications to promote plant growth and viability. The present invention thus provides horticultural compositions comprising at least one amphoteric polymer as well as methods of utilizing the compositions in horticultural applications. While not wishing to be bound by any theory, it is believed that the amphoteric polymers of the present invention are so beneficial because of their high affinity for water and their amphoteric nature. The amphoteric polymers of the present invention have such a high affinity for water, that they are even able to absorb water out of the atmosphere under sufficiently humid conditions. Thus, when exposed to water, either through humidity, precipitation, or irrigation, the amphoteric polymers hydrate, i.e., absorb the available water, store the absorbed water, and then release the water upon demand by a plant. In this manner, when applied directly onto, or placed in proximity to, horticulturally viable substrates, the horticultural compositions of the present invention provide a readily available source of water to the substrates. The present invention will now be described in connection with embodiments of the invention involving coated seeds and related methods; compositions that can be coated onto horticulturally viable substrates to promote plant health and/or growth and related methods; and growing media and related methods. For example, in one embodiment, the horticultural compositions of the present invention may beneficially comprise at least one horticulturally viable seed bearing a coating comprising the amphoteric polymer of the present invention. The coating may coat only a portion or substantially all of the surface of such one or more seeds. The coated seeds of the present invention may be topically applied to, or planted within, a growing medium by any suitable means, including sowing, hydroseeding, gel seeding, or the like.

In addition to the amphoteric polymer of the present invention, the coating may also include one or more optional nutrients (as defined above) that may be incorporated into the coating in order to promote the germination, growth, and/or health of the coated seed. Representative examples of such agents include fertilizer; a binder or adhesive; a pesticide; a herbicide; a game repellent; a nematocide; a fungicide; a growth retardant; a germination promoter; or combinations of these. Such agents are widely commercially available from a variety of sources and may be incorporated into the coating in accordance with conventional practices. The effective amounts of the various plant treatment agents are generally disclosed on the packaging in which they are provided, and furthermore, are generally known to those of skill in the art. To the extent that such amounts are not provided by the commercial source, one of skill in the art would be able to determine an effective amount to be used simply by applying compositions with varying amounts of the additives to test plants and

10 observing the results. If the desired result is not achieved, but the plant exhibits no detrimental effects, the amount used is too low. If the desired result is achieved, but the plant exhibits detrimental side effects, such as browning or wilting, the amount is too high. Due to the strong ionic nature of the amphoteric polymers of the present invention, the horticultural compositions of the present invention show an especially strong affinity for fertilizer salts. Thus, the fertilizer salts are readily incorporated into aqueous solutions of the amphoteric polymers and then are controllably released upon demand by the horticulturally viable substrate. Due to this controlled release of fertilizer, horticultural compositions in accordance with the present invention that comprise one or more fertilizer(s) are particularly useful for application to plants/crops that are otherwise sensitive to fertilizers, such as beans or soybeans. In particular, it would be undesirable for fertilizer-sensitive seeds to be directly contacted with fertilizer, as such contact would typically result in the seed not germinating, or if the seed does germinate, in very slow growth of the seedling. In contrast, if fertilizer is incorporated into the horticultural compositions of the present invention, the fertilizer is released slowly such that the adverse impact of the fertilizer on the seed or seedling is reduced.

Coated seeds of the present invention are easily made using a number of different techniques. According to one simple approach, about 0.1 to about 100, preferably about 1 to about 25 parts by weight of the amphoteric polymer of the present invention are combined with about 100 parts by weight of a suitable solvent, such as water. The amphoteric polymer may be water soluble or insoluble depending upon the technique that is used to synthesize the polymer. Additionally, the amount of solvent to be used also will depend to a great extent upon how the coated seeds will be used after coating. Other plant treatment agents as noted above may also be added to the admixture. The admixture may then be mixed until homogeneous. One or more seeds, preferably 1 to 10 parts by weight of seeds per 100 parts by weight of the amphoteric polymer may then be added to

11 the admixture with mixing to ensure that the seed(s) become fully coated with the admixture.

The admixture of coated seeds may be handled in a number of different ways. However, because the coated seeds generally will begin to germinate and grow into seedlings, even when dried and stored in a closed container, it is most desirable to plant the coated seeds in the desired growing medium as soon as possible after coating. Indeed, coated seeds placed into a sealed glass container grew into tall green grass that filled the container after about 10 days, even though the seeds received no additional water or other nutrients in that period.

According to one planting option, for instance, the admixture may be spread over the top of, or mixed into, a suitable growing medium. For example, the admixture may be poured onto the growing medium from a conventional garden container having a spout with a nozzle whose apertures are large enough to allow the coated seeds to pass. The seeds may be tilled or raked into the soil, if desired, but this is not required. This approach is quite effective for growing new grass, for instance, or alternatively, for filling in bare or sparse spots on an already established lawn. In fact, seeds poured onto the top of the ground in this manner have been observed to grow substantially more vigorously than uncoated seeds dropped onto the top of, or raked into, a growing medium. Also, it has been observed that wild animals (particularly birds) tend to readily eat uncoated grass seeds, decreasing yields considerably. In contrast, such animals tend to leave the coated seeds alone. Advantageously, horticultural compositions of the present invention including coated seeds also may be planted using hydroseeding or gel-seeding techniques, if desired. These techniques are particularly advantageous when establishing new lawns from seed for the residential or commercial grower. For hydroseeding applications, the admixture desirably includes enough polymer and solvent and other ingredients commonly used in hydroseeding applications (although the amphoteric polymer of this invention may replace some or all of the

12 polymer ingredients of a conventional hydroseeding formulation) so that the composition may be sprayed over the planting ground using commercially available hydroseeding devices. Each brand of hydroseeding machine tends to operate most effectively when used to spray hydroseeding compositions of a particular viscosity. Accordingly, the admixture generally should include, or be modified to include, a sufficient amount of water or other suitable solvent so as to have the viscosity recommended by the manufacturer of the hydroseeding machine.

The horticultural composition of the present invention may also be formed as, or modified to form, a hydroseeding gel composition comprising coated seeds of the present invention. The gel may then be squeezed, toothpaste fashion, onto a growing medium. Similar to hydroseeding, once a gelled horticultural composition has been applied to a growing medium, the gelled horticultural composition helps to hold the seeds in place and provides the seeds with the necessary moisture to germinate and grow until the roots of the seedlings are long enough to penetrate and bind the underlying growing medium.

Whatever technique is used to plant the coated seeds, the coating on the seeds provides, by means of the amphoteric polymer, the necessary moisture, and optionally, nutrients in the form of a fertilizer or the !ιke, for germination and growth to occur with reduced irrigation demands until the roots of the seedlings are long enough to penetrate and bind the underlying growing medium. Hydroseeding and gel seeding, in particular, provide an easy, care-free method of starting new turf. Conventional lawn care requires substantially constant water availability during the first few critical weeks after seeding to ensure that seeds germinate and that the seedlings thrive. It is common practice to water newly seeded lawns quite frequently, even three times a day, until the new grass is established. In contrast, coated seeds of the present invention require much less irrigation, because coating of the present invention provides the seeds with a readily available source of water. Even in dry environments, irrigation need only take place only once every 2 to 5 days to maintain healthy plants when using coated seeds of the present invention.

13

SUBSTJTUTESHEET (RULE 26) Irrigation demands can also be reduced during the life of the turf if the amphoteric polymer is incorporated into the soil in which the turf is being grown. Thus, hydroseeding or gel seeding techniques may be used in combination with horticultural compositions of the present invention to provide a high emergence and survival rate of seedlings, and thick, lush turf even with infrequent irrigation in the first few weeks after sowing.

In alternative embodiments of the invention, the admixture described above can be topically applied directly onto cut or growing plants instead of being coated onto seeds. For example, the admixture of the present invention can be applied by bare-root dipping the roots of plants into the admixture, or alternatively, by applying the admixture onto the above ground portion of a plant, i.e., the stem, leaves or petals. When applied onto plants in this manner, the plant can readily absorb water and nutrients, if any, from the coating upon demand. Coated plants would thus be healthier than uncoated counterparts. Also, cut flowers and the like that are coated with the admixture would stay looking fresher longer than uncoated counterparts.

The horticultural compositions of the present invention may also be in the form of a growing medium comprising the amphoteric polymer of the present invention. In addition to the amphoteric polymer, the growing medium may also include other soil media, one or more nutrients or other plant treatment agents in accordance with conventional practices, combinations of these, and the like. This embodiment of the invention is particularly advantageous in drought prone areas or areas with sandy soil in which water and/or nutrient management is important.

Preferably, a growing medium of the present invention may include an amount of the amphoteric polymer effective to enhance the water and/or nutrient management characteristics of the growing medium to desired levels. The precise amount will depend upon factors such as the nature of the growing medium, the type of plants to be grown, the method of irrigation, the amount of natural precipitation, the nature of the native soil (pertinent to field applications), and the

14 like. For instance, for potting and hydroponic applications, the growing medium may include from 0.1 to 100 weight percent of the amphoteric polymer relative to the total amount of soil media used in the growing medium. For outdoor applications, or applications involving a substantial area to be planted such that the cost of using soil adjuvants must be economically practical, the growing medium may include from 0.5 kg to about 100 kg, preferably 1 kg to 40 kg of amphoteric polymer per 100 square meters of field area to be planted, wherein the amphoteric polymer may be topically applied or tilled into the soil to a depth of about 1 cm to 1 ft most typically. Growing media comprising the amphoteric polymer may be provided in a variety of different embodiments. For example, according to one approach, an admixture as described above for coating seeds and comprising the amphoteric polymer may be topically applied by pouring, spraying, curtain coating, or the like, onto the surface of a soil in which plants are to be grown. The admixture may be applied directly onto already established plants, or applied onto soil in which plants will be grown from seed to be subsequently planted, or applied concurrently with seeds to be planted in accordance with hydroseeding techniques, gel seeding techniques, or the like. Optionally, the admixture can be tilled into the soil after application, although this is not required. As another option, seeds can be topically dropped onto the surface of the soil, after which the soil and seeds are topically coated with the admixture. This approach works well if the seeds are coated as described above. Even though such coated seeds are only topically applied to the soil, the protective covering of the admixture helps protect the seeds and promote germination to get a good yield of seedlings and, following that, mature plants. This topical approach for sowing seeds is particularly advantageous because the need to use expensive equipment to plant seeds in the ground to some depth is entirely avoided. Of course, the seeds to be planted can still be planted in the ground, rather than topically applied if desired.

15 The horticultural compositions of the present invention are uniquely characterized by an amphoteric polymer comprising first and a second pendant functional moieties whose ionic character results in the polymer being capable of being cationic, anionic, or zwitterionic, depending upon pH. In preferred embodiments, the amphoteric polymer is cationic at acidic pH (e.g., below about 6), zwitterionic over a neutral pH range (e.g., 6 to about 7.5), and anionic at basic pH (e.g., above about 7.5).

Preferably, the first pendant functional moiety is a moiety that is capable of being deprotonated at neutral and basic pH to form an anion, but is protonated to become nonionic at acidic pH. Representative examples of such functionality include carboxylate, phosphonate, phosphate, sulfonate, sulfate, and combinations thereof. Of these moieties, carboxylate is preferred.

Preferably, the second pendant functional moiety is a moiety that is capable of being protonated at neutral and acidic pH to form a cation, but is deprotonated to become nonionic at basic pH. Representative examples of such functionality include ammonium functionality, phosphonium functionality, sulfonium functionality, and combinations thereof. As used herein, the term "ammonium" refers to a moiety including a nitrogen atom linked to a plurality of moieties by four bonds when dispersed in water at a pH of 7, with the provisos that (1) one of the moieties comprises the polymer backbone which is linked to the nitrogen either directly through a single bond or indirectly through a divalent linking group, and (2) no more than one of the other moieties linked to the nitrogen is hydrogen. The term "sulfonium" refers to a moiety including a sulfur atom linked to three other moieties when dispersed in water at a pH of about 7 with the provisos that (1) one of the moieties comprises the polymer backbone which is linked to the sulfur either directly through a single bond or indirectly through a divalent linking group, and (2) no more than one of the other moieties linked to the sulfur atom is hydrogen. The term "phosphonium" refers to a moiety including a phosphorous atom linked to four other moieties when dispersed in water at a pH of about 7 with the provisos that (1)

16 one of the moieties comprises the polymer backbone which is linked to the phosphorous either directly through a single bond or indirectly through a divalent linking group, and (2) no more than one of the other moieties linked to the phosphorous atom is hydrogen. Preferred examples of such ammonium, sulfonium, and phosphonium functionality may be represented by the following formulae, respectively:

H

I Θ *— N— Ri

(1)

R Ri

/

(2)

H

Ri

-P— R₂

(3)

H

In these formulae, the single bonds denoted with the "*" are linked directly or indirectly to the polymer backbone; and Ri and R₂ are each independently any suitable monovalent moiety subject to the provisos above. If desired, each may be straight, branched, or cyclic in structure. Further, pairs of the Ri and R₂ substituents on any one moiety may be comembers of a ring structure linked to the nitrogen, sulfur, or phosphorus atom, as the case may be, through such pairs. As representative examples, each of Ri and R₂, may independently be selected from a

17 cycloalkyl moiety, a branched alkyl moiety, a straight alkyl moiety, an alkaryl moiety, an aryl moiety, an alkoxy moiety, combinations of these, and the like. Preferably, each of Ri and R₂ is independently an alkyl group of 1 to 20, preferably 1 to 4, and most preferably 1 to 2 carbon atoms. In preferred embodiments, any of Ri and R₂, is -CH₃.

The amphoteric polymers can incorporate a wide range of first and second pendant functional moieties with beneficial results. Preferably, the amphoteric polymers would include a sufficient amount of such moieties such that the amphoteric polymers are water compatible over a pH range including acidic, neutral, and basic pH values. Preferably, this would be a pH range of from about 5 to about 9, more preferably about 2 to about 11. To achieve such water compatibility characteristics, independently providing amphoteric polymers with an equivalent weight of each pendant functionality moiety in the range from 170 to 900,000 grams/equivalent, preferably from 170 to 150,000 grams/equivalent, more preferably from about 170 to 1000 grams/equivalent, would be suitable in the practice of the present invention. The principles of the present invention can be applied to amphoteric polymers having a wide range of molecular weights as well. For example, preferred amphoteric polymers for use in the horticultural composition of the present invention may have a weight average molecular weight in the range from about 1000 to about 1.8 million, preferably from about 1000 to about 300,000.

In preferred embodiments of the horticultural compositions of the invention, the amphoteric polymer comprises first pendant functional moieties that comprise carboxylate functionality and second pendant functional moieties that comprise ammonium functionality. These embodiments of such amphoteric polymers preferably comprise a plurality of first and second chain segments, wherein the first chain segments have the formula:

18 ( C )

Xi

I (4)

C = O

O^θ and wherein the second chain segments have the formula

( C )

χ₂

(5)

In Formulae (4) and (5), each of Xi and X is independently a single bond or a divalent linking group, and A^θ is a positively charged, ionic moiety comprising a nitrogen atom covalently linked to four moieties with the proviso that no more than one of said four moieties is hydrogen. In the practice of the present invention, if either Xi or X₂ is a divalent linking group rather than a single bond, then any divalent moiety which is capable of linking the carboxylate to the polymer backbone, in the case of Xi, or A^θ to the polymer backbone, in the case of X , may be used Accordingly, any divalent linking group that can achieve such objectives would be suitable in the practice of the present invention

19 In embodiments of the invention in which X, and/or X₂ is a divalent linking group, such divalent linking group preferably has the formula:

C=O

(6) X₃

I wherein X₃ is a divalent moiety having a molecular weight in the range from about 40 to about 2500 and Y₂ is selected from -0-, -NH-, -S-, or -NR₃-, wherein R₃ is a monovalent moiety other than hydrogen. Representative examples of suitable divalent linking groups for use as X₃ include divalent groups that comprise an alkylene moiety, a polyether moiety, a perfluorinated polyether moiety, a polyester moiety, a polyurethane moiety, a polycarbonate moiety, a polyimide moiety, a polyamide moiety, an aryl moiety, an alkaryl moiety, an alkoxyaryl moiety, combinations thereof and the like.

Generally, the molecular weight and/or chemical structure of X₃ may be selected to provide the amphoteric polymer with certain kinds of properties as desired. For example, if it is desired for the amphoteric polymer to be able to form rigid or hard bodies, then X₃ may be a lower molecular weight divalent group or a larger divalent group with a rigid backbone. On the other hand, if it is desired for the amphoteric polymer to be able to form elastic, rubbery, or soft bodies, then X₃ may be a divalent group with a flexible backbone such as a polyether chain segment.

In embodiments of the invention in which it is desired that the amphoteric polymer be able to form rigid, hard bodies, Xi is a single bond, and X₂ has a structure according to Formula (6) wherein X₃ is an alkyl group of 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, more preferably — CH₂CH₂ — . In embodiments in which it is desired that the amphoteric polymer be able to form

20 elastic, rubbery, or soft bodies, then Xi may be a single bond, and X₂ may be a polyether moiety having a molecular weight in the range from about 44 to about 2500, more preferably about 200 to about 900. Although such polyether groups are not part of the main polymer backbone, such groups engage in flexible interactions with other polymer molecules.

The ratio of the first pendant functional moieties to the second pendant functional moieties relative to each other may be selected within a wide range. However, if there are too few of the first pendant functional moieties, the polymer may not have sufficient ionic character for a desired application in basic environments. On the other hand, if there are too few of the second pendant functional moieties, the polymer may not have sufficient ionic character for a desired application in acidic environments. Accordingly, it is desirable if the molar ratio of the first pendant functional moieties to the second pendant functional moieties is in the range from 100: 1 to 1: 100, preferably 20: 1 to 1:20, more preferably about 1 :1.

Embodiments of the invention according to formulae (4) and (5) in which the ratio of first chain segments to second chain segments is 1 : 1 are particularly advantageous. As one very important advantage, separate counterions for the carboxylate and ammonium moieties are not required at such a ratio, because the carboxylate serves as the counterion for the ammonium and vice versa. Avoiding the presence of separate counterions is desirable in many applications due to the fact that counterions, particularly metal counterions, are often reactive in undesirable ways. For example, separate counterions can oxidize metals in close proximity to the amphoteric polymer, are subject to ion exchange, can be toxic to plants and affect ion concentration. Thus, in preferred embodiments, amphoteric polymers for use in the horticultural composition of the present invention are provided with built-in counterion capability so that the use of separate counterions may be avoided.

In such embodiments, it is desirable if the first and second chain

21 segments are in sufficiently close proximity to facilitate the ability of the carboxylate and ammonium moieties to act as counterions for each other. Thus, it is desirable if at least a portion of the first and second chain segments are covalently linked to each other such that the amphoteric polymer comprises a plurality of amphoteric chain segments of the formula

( C - C ,

Xi χ₂

(7)

O=C

O^θ

Carboxylate and ammonium moieties associated with each other on a 1 : 1 basis in accordance with Formula (7) shall be referred to herein as an "amphoteric pair" When a portion of the carboxylate and ammonium moieties are associated as amphoteric pairs, the number of separate counterions required for ionic neutrality is reduced. In embodiments of the present invention wherein the amphoteric polymer comprises a ratio of first chain segments to second chain segments of 1 : 1, it is preferred that substantially all of the carboxylate and ammonium moieties be associated in amphoteric pairs in accordance with Formula (7). In such embodiments, the need for separate counterions is advantageously completely avoided, although such counterions may still be included, if desired. A specific example of a preferred embodiment of a chain segment according to formula (7) has the formula:

22

SUBSΠTUTE SHEET (RULE 26 ( c C )

O=C C=O

O^θ O

CH₂

(8)

I CH₂

H₃C— N— CH₃

I Θ

H

It may be further desirable for each amphoteric pair of an amphoteric polymer, such as the amphoteric pairs shown in Formulae (7) or (8), to be spaced apart from other amphoteric pairs. Accordingly, it may be desirable for the amphoteric polymer to further incorporate backbone chain segments of at least two carbon atoms between pairs in order to achieve this objective. In preferred embodiments of the invention, such additional backbone chain segments are derived from ethylene such that the amphoteric polymer comprises a plurality of chain segments of the formula

( C C C C )

Xi X

I I

(9) O=C C=O

O^θ A^θ

Each amphoteric pair included in a structure according to formula (9) is thus spaced apart from other pairs by a polymer backbone segment comprising the two carbon atoms derived from ethylene.

23 Optionally, each of the plurality of second pendant functional moieties of the present invention may further be complexed with a separate, anionic counterion. When used, representative examples of such a counterion, designated herein as M⁶, include a halogen atom, sulfates, carbonates, nitrates, perchlorates, combinations thereof, and the like. However, as described above, use of such counterions is optional in that embodiments of the present invention can be prepared in which a corresponding first pendant functional moiety serves as the second pendant functional moiety counterion and vice versa.

Even when the use of separate counterions is not required, such counterions may desirably be included. For example, in applications where it is desirable that the amphoteric polymer have as high an ionic concentration as possible, it may be desirable to include separate counterions. An example of such an application would be that embodiment of the invention wherein the horticultural composition comprises an amount of fertilizer. Amphoteric polymers for use in the horticultural compositions of the present invention show tremendous compatibility with water. More specifically, amphoteric polymers with substantially linear backbones are very water-soluble over a wide range of pH values and concentrations. Other embodiments of amphoteric polymers useful in the horticultural compositions of the present invention may also be formed with branched structures such that the amphoteric polymers are water-insoluble while still showing tremendous ability to absorb large quantities of water, e.g., several times their weight in water. Typically, then, such branched embodiments of the present invention form gels upon hydration and are thus particularly suitable for gel-seeding applications. An amphoteric polymer with a branched structure, i.e., a water- insoluble, water-absorbing amphoteric polymer, can be made in several ways. According to one approach, an amphoteric polymer may be prepared by incorporating a plurality of chain segments derived from N,N'- methylenebisacrylamide into the amphoteric polymer. The use of N,N'-

24 methylenebisacrylamide to make superabsorbent polymers has been described in J. Chem. Ed., "Synthesis of Superabsorbent Polymers", vol 74, pp. 95-6. According to another approach, an amphoteric polymer with a branched structure may be prepared by incorporating a multifunctional monomer into the polymer backbone such that the resultant backbone of the amphoteric polymer is sufficiently branched so that the polymer absorbs water, but is water-insoluble. In embodiments of the invention in which the amphoteric polymer is a vinyl copolymer, such multifunctional monomers include monomers comprising a plurality of carbon- carbon double bonds, preferably at least three carbon-carbon double bonds. Representative examples of such multifunctional monomers include divinylbenzene, ethylene glycol diacrylate, butylene glycoldiacrylate, triallylamine, diethyleneglycol diacrylate, triallylamine, allylmethacrylate, 1,1,1,-trimethylolpropane triacrylate, tetraallyloxyethane, combinations of these, and the like.

A wide range of amounts of monomers such as N,N'- methylenebisacrylamide, or a monomer comprising a plurality of carbon-carbon double bonds, combinations thereof, or the like, may be incorporated into an amphoteric polymer with beneficial results. As a practical matter, the amount of such monomers incorporated into an amphoteric polymer will depend to a great extent upon the amount of water absorbent characteristics which are desired in the final polymer product as well as the application in which the polymer will be used. Generally, using greater amounts of such monomer or monomers provides a polymer with greater water absorbing capabilities up to a practical limit beyond which using more monomer provides little added benefit. As a representative range, incorporating 0.01 to 0.5 mole percent of such monomer or monomers into an amphoteric polymer would be suitable in the practice of the present invention.

Amphoteric polymers of the present invention may be prepared using a variety of approaches. According to one approach, a polymer comprising one or more chain segments having maleic anhydride functionality of the formula

25

i.e., a first reactant, is reacted with a second reactant comprising a tertiary amine moiety and a nucleophilic moiety. The nucleophilic moiety undergoes a nucleophilic reaction with the maleic anhydride functionality of the polymer, thereby linking said second reactant to one of the carboxyl moieties of the maleic anhydride group while simultaneously forming a carboxylate. This approach is schematically illustrated in Figure 1. As shown in

Figure 1, a first reactant is a maleic anhydride functional polymer comprising a maleic anhydride chain segment 10 having two carboxyl groups cyclically linked to each other via an oxygen atom. The polymer incorporating chain segment 10 may be any polymer incorporating one or more of such maleic anhydride chain segments. Preferably, however, the first reactant including chain segment 10 is a vinyl copolymer obtained by copolymerizing vinyl monomers comprising maleic anhydride and optionally one or more other vinyl monomers. A particularly preferred vinyl copolymer of the present invention is an alternating block copolymer of ethylene and maleic anhydride having a weight average molecular weight in the range from 1,000 to 1.8 million. Advantageously, such copolymers have excellent spacing (two carbon atoms in the backbone provided by the ethylene) between anhydride groups while otherwise maximizing the anhydride content of such copolymers.

The use of such copolymers results in the production of amphoteric polymers characterized by a molar ratio of carboxylate to ammonium moieties of 1 : 1 so that separate counterions are not required. Additionally, the amphoteric polymers so produced comprise amphoteric pairs according to Formula (7) above. The amphoteric polymers so produced are also extremely water compatible due to

26 the resultant high content of carboxylate and ammonium moieties.

Second reactant 12 comprises divalent linking group X₃, nucleophilic moiety Yi, and moiety A. Representative examples of nucleophilic moieties suitable for use as Yi include -OH, -NH₂, -SH, and -NHR₃, wherein R₃ is a monovalent moiety other than hydrogen. In preferred embodiments, R₃ is an alkyl group of 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, more preferably -CH₃. The divalent linking group X₃ has been defined above with respect to Formula (6), and is preferably selected from an alkylene group of 1 to 20 carbon atoms or a polyether moiety having a weight average molecular weight in the range from 44 to about 900 The moiety A is a moiety comprising an amine group having a nitrogen atom linked to X₃ and to two monovalent substituents, wherein neither substituent is hydrogen or an acidic group. Preferably, moiety A is represented by the formula:

R4

(11)

-N— R₅

wherein the single bond denoted with the "*" is linked to X₃, and each of Rj and R5 is independently a monovalent moiety other than hydrogen or an acid group. In preferred embodiments, each of > and R5 is independently an alkyl group of 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, more preferably - CH₃

One preferred class of compounds suitable for use as second reactant 12 is represented by the formula

f

(12) Y,— CH₂CH₂— N— R₅

wherein Y_ls R>, and R5 have been defined above. A specific example of one such compound found to be suitable in the practice of the present invention has the

27 formula

CH₃

(13)

HO— CH₂CH₂N— CH₃

According to one set of preferred reaction conditions, the first reactant incorporating chain segment(s) 10 and second reactant 12 are reacted together at room temperature in a suitable nonaqueous, polar solvent, such as THF or ether, at a substantially neutral pH. The reaction is self-catalyzed so that a catalyst and initiator are not required.

The reaction between the first reactant including chain segment 10 and second reactant 12 may be considered as yielding intermediate reaction product incorporating chain segment 14. If first reactant chain segment 10 includes a plurality of maleic anhydride chain segments, then the intermediate reaction product will likewise include a corresponding plurality of chain segments 14. As shown by Figure 1, the nucleophilic moiety reacts with one of the carboxyl moieties to form linkage Y₂ between the carboxyl group and the divalent linking group X₃. The nature of Y₂ depends upon what kind of nucleophilic moiety is used as Yi. For example, if Yi is OH, then Y₂ is -O-. If Yi is -SH, then Y₂ will be -S-. If Yi is - NH₂, then Y₂ will be -NH-. If Yi is -NHR₃, then Y₂ will be -NR₃-. As a result of the reaction between the nucleophilic moiety and the carboxyl moiety, the moiety A becomes pendant from the polymer backbone. As seen from the structure of chain segment 14, the other carboxyl group of the chain segment 10 forms -COOH. The hydrogen on this -COOH group spontaneously shifts to the A moiety. As a result, the -COOH becomes an ionic carboxylate group, and the tertiary amine group A becomes the corresponding protonated ammonium group A^θ. Amphoteric polymer chain segment 16 results. Advantageously, the resultant carboxylate and ammonium moieties form amphoteric pairs. Each ionic moiety is thus capable of acting as a counterion for the other.

28 Generally, each chain segment 10 tends to react with only one second reactant 12 so that the reaction scheme provides a very high yield of amphoteric chain segments 16. Very few, if any, of the chain segments 10 will react with two second reactants 12 such that both carboxyl groups form linkages to the A groups.

A specific application of the reaction scheme of Figure 1 is illustrated in Figure 2. There, first reactant 20 is a chain segment of a 50:50, alternating block, vinyl copolymer of ethylene and maleic acid anhydride. Second reactant 22 corresponds to a compound of Formula (12) in which Yi is -OH, and each of R and R₅ is -CH₃. The maleic acid anhydride moiety of first reactant 20 reacts with second reactant 22 to form a polymer comprising chain segment 24 having pendant -COOH and tertiary amine functionality. The hydrogen on the - COOH moiety spontaneously shifts to the tertiary amine moiety. Thus, the -COOH becomes an ionic carboxylate moiety and the tertiary amine moiety becomes the corresponding protonated ammonium moiety. Amphoteric polymer chain segment 26 is thereby produced.

According to another approach for preparing amphoteric polymers useful in the horticultural composition of the present invention, amphoteric polymers are formed by copolymerizing vinyl monomers comprising a tertiary amine functional vinyl monomer, an acid functional vinyl monomer, and optionally one or more additional copolymerizable vinyl monomers (not shown) as desired. The acid group of the acid functional monomer is preferably -COOH, but could also be the protonated form of sulfate, sulfonate, phosphate, phosphonate, or the like. Representative examples of additional vinyl monomers include vinyl acetate, vinyl chloride, vinylidene chloride, divinyl benzene, styrene, a-methyl styrene, alkylated styrene, alkoxy styrene, alkyl(meth)acrylate, acrylonitrile, hydroxy functional (meth)acrylate, vinyl naphthalene, alkylated vinyl naphthalene, alkoxy vinyl naphthalene, (meth)acrylamide, (meth)acrylimide, N-vinyl pyrolidone, isobornyl (meth)acrylate, allyl (meth)acrylate, combinations of these, and the like. If it is

29 desired to form water-insoluble amphoteric polymers capable of absorbing large quantities of water, then such additional vinyl monomer(s) may include N,N'- methylenebisacrylamide, multifunctional vinyl monomers comprising at least two, preferably three carbon-carbon double bonds, combinations of these, and the like. This approach for copolymerizing vinyl monomers is schematically shown in Figure 3. There, first reactant 30 may be any vinyl monomer comprising a tertiary amine moiety and a polymerizable carbon-carbon double bond. According to the preferred structure shown for first reactant 30, A represents a moiety of the formula

R»

(14)

-N— R₅ wherein R and R₅ are each independently a monovalent moiety other than hydrogen. In preferred embodiments, each of R and R₅ is independently an alkyl group of 1 -20 carbon atoms, preferably an alkyl group of 1 to 4 carbon atoms, more preferably -CH₃; X₃ is a divalent linking group according to the definition of X₃ given for Formula (6) above; and Re is hydrogen or a lower alkyl group of 1 to 4 carbon atoms, preferably hydrogen or -CH₃.

Second reactant 32 may be any vinyl monomer comprising acid functionality and a polymerizable carbon-carbon double bond. According to the preferred structure for second reactant 32 shown in Figure 3, second reactant is a (meth)acrylic acid type compound, wherein Re is as defined above. Other examples of compounds suitable for use as second reactant 32 include acrylic acid, p-vinyl benzoic acid, and the like.

First reactant 30, second reactant 32, and other vinyl monomers if any, may be reacted together within a wide range of concentrations relative to each other. Appropriate amounts can be selected in accordance with conventional practices to provide resultant amphoteric polymers having the molecular weight

30 ranges and molar ratios between functional groups as described above. Preferably, the molar ratio of the first reactant 30 to the second reactant 32 is in the range from 1:100 to 100: 1, preferably 1: 10 to 10: 1, more preferably about 1: 1.

The vinyl copolymers of the present invention of Figure 3 may be prepared using any suitable free radical polymerization technique including bulk, solution, emulsion, and suspension polymerization methods. For example, according to a preferred manner of carrying out solution polymerization, first reactant 30 and second reactant 32 are added to water. By themselves, i.e., not in the presence of each other, second reactant 32 (acrylic acid) is readily water soluble, but first reactant 30 (the methacrylated amine) is not. However, when the two reactants 30 and 32 are combined in water at a neutral pH, the acidic hydrogen on second reactant 32 shifts over and protonates the A moiety of first reactant 30. Both reactants 30 and 32 are ionic and fully water soluble as a result, making it easy to now carry out the polymerization in water. After reactants 30 and 32 are added to water and dissolved, optional additives such as a chain-transfer agent, a free radical polymerization initiator, or the like, may be added to facilitate the polymerization. To carry out the polymerization, the solution may be sealed in an inert atmosphere and then agitated at a temperature sufficient to activate the initiator. Free radical initiators suitable for solution polymerization include those that are soluble in the reaction solvent, including, but not limited to, azo compounds, peroxides, and combinations of these. Representative examples of useful peroxide initiators include those chosen from benzoyl peroxide, lauroyl perodice, di-t-butyl peroxide, and the like. Representative examples of useful azo compound initiators include those chosen from the group consisting of 2,2'- azobis(2-methylbutyronitrile), and 2,2'azobis(isobutyronitrile). A preferred initiator is 2,2'azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride commercially available under the trade designation VA-044 from Wako Chemicals USA Inc., Richmond, VA.

31 According to particularly preferred conditions for carrying out the polymerization reaction of Figure 3, equimolar amounts of the vinyl monomers are copolymerized at elevated temperature in aqueous solution containing 1-10 mole percent, preferably 1 to 5 mole percent, initiator based upon the monomers to be copolymerized. The resultant copolymer 38 comprises one or more carboxylate functional chain segments 34 and one or more ammonium functional chain segments 36 in the backbone of copolymer 38.

Figure 4 illustrates a particularly preferred, two-step reaction scheme for preparing first reactant 30 shown in Figure 3. According to the first reaction step shown in Figure 4, tertiary amine nucleophile 40 is reacted with (meth)acrylate functional acyl halide 42 to provide ammonium functional (meth)acrylate 44. In tertiary amine nucleophile 40, A is a moiety of the formula:

R₄

(15)

-N— R₅ wherein each of R₄ and R₅ is as defined above with relation to Formula (14). X₃ is a divalent linking group according to the definition of X₃ given for Formula (14) above. Preferably X₃ is -CH₂CH₂- or a polyether moiety having a molecular weight in the range from about 44 to about 900. Yi is a nucleophilic moiety, preferably -OH. In (meth)acrylate functional acyl halide 42, Y₃ is a halogen atom, preferably chlorine. Y₂ and Re are as defined above in connection with Figure 1. A^θ is the protonated form of A.

As one set of conditions for carrying out the first reaction step of Figure 4, the reaction takes place at room temperature in a solvent such as THF or ether, wherein the molar ratio of reactant 40 to reactant 42 is about 1: 1. The reaction is self-catalyzed, and yields of about 100% have been achieved. In the second reaction step shown in Figure 4, the ammonium functional (meth)acrylate 44 is treated with an aqueous base, such as sodium

32 hydroxide (NaOH), potassium carbonate (K₂CO₃) or the like, in order to deprotonate the ammonium moiety to produce reaction product 46, a tertiary amine functional (meth)acrylate Reaction product 46 is then extracted into an organic solvent, such as ether, and the solvent subsequently removed to recover reaction product 46, thereby removing any added counterions and providing a tertiary amine functional (meth)acrylate 46 suitable for use as first reactant 30 in Figure 3

Amphoteric polymers useful in the horticultural compositions of the present invention may also be prepared by polymerizing a monomer having tertiary amine functionality and a polymerizable carbon-carbon double bond with a monomer comprising acid functionality and a polymerizable carbon-carbon double bond vie free radical polymerization Preferably, the molar ratio of these monomers relative to each other is in the range from 1 100 to 100 1, preferably 1 10 to 10 1, more preferably about 1 1 As a result, the carboxylate moiety of the one monomer as well as the tertiary amine moiety of the other monomer become pendant from the resultant polymer backbone

A representative example of this approach is illustrate schematically in Figure 5 As shown, a first reactant 50, (meth)acrylic acid, and a second reactant 52, a (meth)acrylate functional tertiary amine, are copolymerized to form copolymer 58 comprising carboxylate functional chain segment 54 and ammonium functional chain segment 56 in the backbone of copolymer 58 Of course, (meth)acrylιc acid and the (meth)acrylate functional tertiary amine are merely representative of the types of monomers that can be copolymerized to form copolymer 58 Other examples of compounds suitable for use as first reactant 50 include lmidazoles Other examples of compounds suitable fur use as second reactant 52 include vinyl sulfonates Other vinyl monomers may also be copolymerized with first reactant 50 and second reactant 52, if desired For example, multifunctional (meth)acrylate monomers, as described above, may be used if a branched, water insoluble, water absorbing copolymer is desired Copolymer 58 may be prepared using any suitable free radical polymerization technique including

33 bulk, solution, emulsion, and suspension polymerization methods, as described above with relation to Figure 3. Water is a preferred solvent for carrying out the reaction.

As seen from the structure of chain segment 54, the carboxyl group of first reactant 50 corresponds to the pendant -COOH moiety of chain segment 54. Under neutral or acidic pH conditions, the hydrogen on this -COOH group spontaneously shifts to the tertiary amine moiety of chain segment 56. As a result, the -COOH becomes an anionic carboxylate group, and the tertiary amine moiety becomes the corresponding cationic ammonium group. Zwitterionic polymer 58 results.

In yet another approach, amphoteric polymers useful in the horticultural compositions of the present invention may also be prepared by a two- step reaction scheme. The first step involves copolymerizing a (meth)acrylate functional tertiary amine and a maleic anhydride monomer, and the second step involves reacting the resultant intermediate product with an alcohol. This approach is illustrated schematically in Figures 6 A and 6B.

As shown in Figure 6A, a first reactant 60, maleic anhydride, is copolymerized with a second reactant 62, a (meth)acrylate functional tertiary amine, to form intermediate copolymer 64 comprising anhydride functional chain segment 66 and ammonium functional chain segment 65 in the backbone of intermediate copolymer 64. Of course, maleic anhydride and the (meth)acrylate functional tertiary amine are merely representative of the types of monomers that can be copolymerized to form intermediate copolymer 64. The reaction of Figure 6 A may be carried out using any suitable free radical polymerization technique including bulk, solution, emulsion, and suspension polymerization methods, as described above with relation to Figures 3 and 5.

In the second step of the reaction as shown in Figure 6B, the intermediate copolymer 64 is reacted with an alcohol 67, e.g., ethanol, to form polymer product 68. As an alternative to using ethanol, other alcohols may be

34 used instead, such as propanol, butanol, and the like. The alcohol group of the alcohol functions as a nucleophilic moiety that undergoes a nucleophilic reaction with the anhydride group, linking to one of the carboxylate moieties while the other carboxylate moiety becomes pendant from the polymer backbone. Alcohol 67 may also have multiple hydroxyl groups, i.e, alcohol may be a diol or triol, in which case, resultant polymer product 68 would comprise pendant hydroxyl functionality, and thus, would be crosslinkable.

The present invention will now be further described with reference to the following Examples. Example 1

N,N-dimethylethanol amine (8.5 g) was added to a solution of low molecular weight 50/50 ethylene/maleic anhydride copolymer (3.0 g) in tetrahydrofuran (150 mL). The reaction was stirred under N₂ at 25°C for 21 hours. The tetrahydrofuran was removed by rotoevaporating under house vacuum with the use of a 40°C water bath. The residue was washed with two 275 mL aliquots of diethyl ether. The diethyl ether was decanted and the product was placed into a vacuum over at 25°C under house vacuum for 17 hours.

Example 2 2-[2-(dimethylamino)ethoxy] ethanol (12.7 g) was added to a solution of low molecular weight 50/50 ethylene/maleic anhydride copolymer (3.0 g) in tetrahydrofuran (150 mL). The reaction was stirred under N for 21 hours. After 96 hours of additional stirring, the tetrahydrofuran was removed by rotoevaporating under house vacuum with the use of a 40°C water bath. The residue was washed with two 100 mL aliquots of tetrahydrofuran followed by one aliquot of diethyl ether (140 mL). The product was placed into a vacuum oven at 25°C under house vacuum for three hours.

35 Example 3

N,N-dimethylethanol amine (11.5 g) was added to a solution of high molecular weight 50/50 ethylene/maleic anhydride copolymer (5.0 g) in tetrahydrofuran (200 mL). The reaction was stirred under N₂ at 25°C for 23 hours. More N,N-dimethylethanol amine (23.8 g) was added to the reaction mixture. The reaction was stirred under N₂ at 25°C for an additional 21 hours. The tetrahydrofuran was decanted and the precipitate was washed with one aliquot of tetrahydrofuran (200 mL) followed by two 175 mL aliquots of diethyl ether. The product was placed into a vacuum oven at 25°C under house vacuum for 24 hours.

Example 4

2-[2-(dimethylamino) ethoxy] ethylene acrylate (5.2 g) was added to a solution of acrylic acid (2.0 g) in deionized water (20 mL). N,N-methylene-bis- acrylamide (500 mg) was added. The solution was deaerated while stirring for 45 minutes under house vacuum. After this period of time, 2,2'-azobis[2-(2- imidazolin-2-yl) propane] dihydrochloride (0.10 g) was added to the stirring solution. The flask was vented and then immersed in a 95°C mineral oil bath for 5 minutes. A transparent polymer gel formed which was later removed from the flask and dried in a vacuum oven at 25°C. The resulting product absorbs water while remaining insoluble.

Example 5

2-[2-(dimethylamino) ethoxy] ethanol (7.4 g) was added to a solution of acryloyl chloride (5.0 g) in diethyl ether (125 mL). The reaction was stirred under N₂ at 25°C for 2 days. The reaction mixture was extracted with five 125 mL aliquots of 5% (w/w) NaOH (aq). The organic phase was separated and the diethyl ether was removed by 2 rotoevaporating under house vacuum with the use of a 35°C water bath. The product, 2-[2-(dimethylamino) ethoxy] ethylene acrylate, was a light yellow oil.

36 Example 6

A_ Reagents

The reagents used in this Example are illustrated in Table 1, below

Table 1 Reagent CAS # MW

Acrylic Acid 79-10-7 72.06

2-(dimethylamino)ethyl acrylate 2439-35-2 143.19

Distilled Water 18 01

VA-044 287 88 Wako Thermal Polymerization Initiator

2HCI

B_ Procedure

The polymer was prepared as follows Distilled water (866 mL) was placed into a

2 0 L split reactor flask equipped with a magnetic stirbar The flask was stirred under vacuum for one hour in order to remove dissolved oxygen from the water After one hour, the flask was removed from the vacuum and opened to a positive nitrogen atmosphere Acrylic acid (144 12 g, 2 0 mol) and 2-(Dimethylamino) ethyl acrylate (286 38 g, 2 0 mol) were added to the water by quickly pouring from graduated cylinders The contents of the flask were then stirred under vacuum for 30 minutes Meanwhile, VA-044 (8 66 g, 0 03 mol) was dissolved into 43 mL distilled water in a 250 mL round bottom flask equipped with a magnetic stirbar The flask was stirred under vacuum for 30 minutes to deoxygenate

37 Positive nitrogen pressure was established in both flasks and the VA- 044 solution was cannulated into the split reactor solution with stirring. The resulting solution became very hot and solidified into a yellow gel within 30 minutes. No external heat source was applied. The polymer solution was stirred for 2 hours and then opened to ambient pressure. The polymer was then placed into a 43° C vacuum oven to dry. The resulting dried polymer was extremely hard.

This reaction scheme is schematically illustrated in Figure 7.

Example 7 A. Reagents

The reagents used in this Example are illustrated in Table 2, below.

Table 2

Reaεent CAS # MW

Malaic Anhydride 108-31-6 98.06

2-(dimethylamino)ethyl acrylate 2439-35-2 143.19

Ethanol, absolute 64-17-5 46.07

Tetrahydrofuran, anhydrous 109-99-9 72.11

VA-044 287.88

Wako Thermal Polymerization Initiator

Distilled Water 7732-18-5 18.01

Procedure

The polymer was prepared as follows. A 100 mL round-bottom flask equipped with a magnetic stirbar was flame-dried and cooled under nitrogen. 2.00 g (0.0204 mol) of malaic anhydride were placed into the flask and the flask purged with nitrogen. 40 mL of THF were added to the flask via cannulation. 1.20 mL (0.0204 mol) ethanol followed by 3.10 mL (0.0204 mol) of 2- (dimethylamino)ethyl acrylate were then added to the flask, both via disposable

38 syringe The resulting yellow solution was allowed to stir overnight at room temperature, under positive nitrogen pressure

There was no precipitate present the next morning An additional 40 mL of THF was added to the flask via cannulation and nitrogen gas was bubbled through the solution The solution turned cloudy, however, no precipitate formed A reflux condenser was then attached to the flask and the solution was heated to approximately 66° C, the boiling point of THF The solution was held at this temperature overnight, under positive nitrogen pressure

The following day, there was still not precipitate present However, there was a small amount of dark brown oil settled at the bottom of the flask The remaining THF was decanted into a 200 mL roundbottom flask and evaporated under vacuum to yield 5 69 g of isolated brown oil A magnetic stirbar and 15 mL water were added to the flask, and the contents of the flask stirred for one hour under vacuum, to remove any dissolved oxygen from the water After one hour, the vacuum was turned off and the flask was opened to a positive nitrogen atmosphere

Meanwhile, 0 088 g of VA-044 (0 00031 mol) was dissolved in 0 5 mL distilled water in a 3 0 mL reaction vial equipped with a magnetic stirbar The vial was stirred for 30 minutes under vacuum to deoxygenate Positive nitrogen pressure was established in both flasks and the VA-

044 solution was cannulated into the solution in the roundbottom flask with stirring The resulting solution was heated to about 40° C, and maintained at this temperature for 2 hours The solution was then allowed to cool slowly to room temperature This reaction scheme is schematically illustrated in Figure 8

Example 8

A_ Reagents

The reagents used in this Example are illustrated in Table 3, below Table 3

39 Reagent CAS # MW

Malaic Anhydride 108-31-6 98.06

2-(dimethylamino)ethyl acrylate 2439-35-2 143 19

Ethanol, absolute 64-17-5 46 07

VA-044 287.88 Wako Thermal Polymerization Initiator

Distilled Water

7732-18-5 18 01

B_ Procedure The polymer was prepared as follows A 250 mL round-bottom flask equipped with a magnetic stirbar was flame-dried and cooled under nitrogen 2 00 g (0 0204 mol) of malaic anhydride was added to the flask and the flask purged with nitrogen 80 mL ethanol was added into the flask and the flask again purged with nitrogen 3 10 mL (0 0204 mol) of 2-(dimethylamino)ethyl acrylate were then added to the flask via disposable syringe The resulting yellow solution was allowed to stir over a weekend at room temperature, under positive nitrogen pressure

There was no precipitate present the following Monday However, there was a small amount of dark brown oil settled at the bottom of the flask The remaining ethanol was evaporated under vacuum to yield 5 05 g of isolated brown oil A magnetic stirbar and 15 mL water were added to the flask, and the contents of the flask stirred for one hour under vacuum, to remove any dissolved oxygen from the water After one hour, the vacuum was turned off and the flask was opened to a positive nitrogen atmosphere Meanwhile, 0 088 g of VA-044 (0 00031 mol) was dissolved in 0 5 mL distilled water in a 3 0 mL reaction vial equipped with a magnetic stirbar The vial was stirred for 30 minutes under vacuum to deoxygenate

Positive nitrogen pressure was established in both flasks and the VA- 044 solution was cannulated into the solution in the roundbottom flask with stirring

40 The resulting solution was heated to about 40° C, and maintained at this temperature for 2 hours. The solution was then allowed to cool slowly to room temperature.

This reaction scheme is schematically illustrated in Figure 9.

Example 9

A. Reagents

The reagents used in this Example are illustrated in Table 4, below.

Table 4

Reaεent CAS # MW

Acrylic Acid 79-10-7 72.06

2-(dimethylamino)ethyl acrylate 2439-35-2 143.19

Deionized Water 18.01

VA-044 287.88

Wako Thermal Polymerization Initiator

B. Procedure

1L of deionized water was placed into an oven-dried 2 L round- bottom flask equipped with a magnetic stir bar. The flask was placed under vacuum to remove the dissolved oxygen. Meanwhile, 10.0 g of VA-044 was dissolved in about 30.0 mL deionized water in an oven-dried round bottom flask equipped with a magnetic stirbar. The flask was stirred for 20 minutes under vacuum to deoxygenate.

In addition, a solution of N,N-methylenebisacrylamide (BIS) was prepared by adding 4.18 g of BIS to another oven-dried round bottom flask equipped with a magnetic stir bar. The flask was stirred for 20 minutes under vacuum to deoxygenate.

The water-containing 2 L round-bottom flask was removed from vacuum and opened to a positive nitrogen atmosphere. 167.2 g of acrylic acid and

41 332.7 g of 2-(dimethylamino)ethyl acrylate was added to the flask via syringe. The resulting solution was stirred under vacuum for 30 minutes. The flask was then removed from under vacuum and opened to a positive nitrogen atmosphere. The BIS solution, followed by the VA-044 solution were then added to the flask via syringe.

The flask was then immersed into a 55° C oil bath, while the contents of the flask were continually stirred. The contents of the flask reacted to form a gel, which was removed from the flask and dried in a vacuum oven. Example 10 A Reagents

The reagents used in this Example are illustrated in Table 5, below.

Table 5 Reagent CAS # MW Acrylic Acid 79-10-7 72.06

2-(dimethylamino)ethyl acrylate 2439-35-2 143.19

Deionized Water 18.01

VA-044 287.88

Wako Thermal Polymerization Initiator

B. Procedure 1L of deionized water was placed into an oven-dried 2 L round- bottom flask equipped with a magnetic stir bar. The flask was placed under vacuum to remove the dissolved oxygen.

Meanwhile, 10.0 g of VA-044 was dissolved in about 30.0 mL deionized water in an oven-dried round bottom flask equipped with a magnetic stirbar. The flask was stirred for 20 minutes under vacuum to deoxygenate.

The water-containing 2 L round-bottom flask was removed from vacuum and opened to a positive nitrogen atmosphere. 167.2 g of acrylic acid and 332.7 g of 2-(dimethylamino)ethyl acrylate was added to the flask via syringe. The resulting solution was stirred under vacuum for 30 minutes. The flask was then

42 removed from under vacuum and opened to a positive nitrogen atmosphere. The VA-044 solution was then added to the flask via syringe.

The flask was then immersed into a 55° C oil bath, while the contents of the flask were continually stirred. The contents of the flask reacted to form a gel, which was removed from the flask and dried in a vacuum oven.

Example 11. Horticultural Compositions comprising Grass Seeds

A Preparation of Horticultural Compositions

A 25%) by weight stock solution of a polymer in water with the present invention was made by dissolving 2.74 g of the amphoteric polymer of

Example 1 (EMA+ dimethyl-aminoethoxy ethanol) in 8.23 mL of distilled water.

Five additional horticultural compositions were then made from this stock horticultural composition by diluting aliquots of the stock horticultural composition to 18%, 10%), 5% 1% and 0.1 % solutions. 4 mL of each concentration of horticultural composition, including the 25% stock horticultural composition, was then added to respective Erlenmeyer flasks.

1.24 g of K-Gro Sunny lawn seed mixture was then added to each flask as well as to a control flask containing 4 mL of distilled water, but no polymer

(i.e., a 0%) solution). The flasks were shaken to ensure that the seeds were coated in the horticultural composition (or control solution) and subsequently allowed to sit for 5 minutes before planting.

E Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled with potting soil (containing perlite), and 50 mL of distilled water was added to each pot. Each of the horticultural compositions (the 25% stock solution, 18%, 10%, 5%, 1%, 0.1%, 0% solutions) were poured over the surface of a respective pot. The pots were left in the greenhouse until the grass seedlings emerged and finally died off. No further water or other nutrients were added to the pots.

C. Results

43 The grass seeds in the 18% and 25% horticultural composition test pots had a low emergence rate Initial emergence of the grass seedlings was approximately even between the 0%, 0 1%, 1%, 5% and 10% horticultural composition test pots

However, after 2 weeks without water or other nutrients, the grass seedlings in the 5% horticultural composition test pot were about 4 times as dense as the grass seedlings in the control test pot In fact, the grass seedlings in the 5% horticultural composition test pot were the longest and densest of all of the grass seedlings at 2 weeks The grass seedlings in the control test pot had started to die off by this time, while the grass seedlings in all of the l%-25% horticultural composition test pots continued to grow The grass seedlings in the 5% and higher horticultural composition test pots lasted about 10 days longer than the grass seedlings in the control test pot, and about 5-7 days longer than the grass seedlings in the 0 1% and 1% horticultural composition test pots These results are shown in Table 6, below

Table 6

Concentration of horticultural Onset of wilting Completely wilted composition fdavs after planting fdavs after planting) 0% (control) 7 11

0 1% 7 11

1 0% 16 17

5 0% 16 17

10 0% 16 17

18 0% 16 17

25 0% 16 17

Example 12. Applying the Horticultural Compositions to Grass Seeds in Test Pots

A_ Preparation of Horticultural Compositions

44 A 25% by weight stock solution of the amphoteric polymer of Example 1 was made by dissolving 10.0 g of the amphoteric polymer in 40 mL distilled water. Five additional horticultural compositions were then made from this stock horticultural composition by diluting aliquots of the 25% stock horticultural composition into 18%, 10%, 5%, 1% and 0.1% solutions. The solutions were stored in Erlenmeyer flasks. A control flask included distilled water. B_, Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled with Bachman's brand Garden Soil. 0.23g of K-Gro Sunny Lawn seed mixture was then sprinkled evenly on the surface of the soil in each pot. 4 mL of each horticultural composition, as well as one control (0%) solution, was applied uniformly on top of the seeds of a respective pot. The pots were left in the greenhouse until the grass seedlings emerged. No additional water or nutrients were added to any pot. C. Results The seeds planted in the 10% horticultural composition test pot seemed to have the highest emergence rate. The longevity of those seedlings planted in horticultural composition test posts was enhanced over the longevity of the seedlings in the control test pot and the soil in the horticultural composition test pots remained moist looking longer than the soil in the control test pot. Thus, this experiment further substantiates the conclusion that coating seeds with the horticultural compositions of the present invention retains soil moisture, provides an enhanced emergence rate, and promotes longevity.

Example 13. Applying the Horticultural Compositions to Test Pots in which Grass Seeds are Incorporated

A, Preparation of Horticultural Compositions

A 25%) by weight stock horticultural composition of the amphoteric polymer of Example 1 was made by dissolving 10.0 grams of an amphoteric polymer in 40 mL distilled water. Five additional horticultural compositions were

45 then made from this stock horticultural composition by diluting aliquots of the 25% stock horticultural composition into 18%, 10%, 5%, 1% and 0.1% solutions. The samples were stored an Erlenmeyer flask. A control flask, containing distilled water, was also prepared. R Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled with Bachman's brand Garden Soil. 0.23g of K-Gro Sunny Lawn seed mixture was then sprinkled evenly on the surface of the soil in each pot. About 1/16th of an inch of soil was then added to the pots to cover the seeds. 4 mL of each horticultural composition, as well as one control (0%) solution, was applied uniformly over the soil in a respective pot. The pots were left in the greenhouse. No further water or nutrients were added to any pot. C. Results

Initial emergence of the grass seedlings in the 10%-25% horticultural composition test pots was more than 5 times that of the grass seedlings in the control test pot. Throughout the experiment, the grass seedlings in the 10% and 18% horticultural composition test pots grew the tallest and densest as compared to the grass seedlings in the control test pot.

The grass seedlings in the 5-25% horticultuiαl composition test pots lasted 18 days before wilting began, while the grass seedlings in the control pot lasted only 11 days until wilting began. Thus, the longevity of those seedlings planted in horticultural composition test posts was enhanced over the longevity of the seedlings in the control test pot and the soil in the horticultural composition test pots remained moist looking longer than the soil in the control test pot.

The data of this example when viewed in combination with the other examples further substiates the conclusion that coating seeds with the horticultural compositions of the present invention retains soil moisture, provides an enhanced emergence rate, and promotes longevity.

46 Example 14. Applying the Horticultural Compositions to Grass Seeds in Test Pots

A Preparation of Horticultural Compositions

A 25% by weight stock horticultural composition of the amphoteric polymer of Example 1 (JE51) was made by dissolving 10 g of an amphoteric polymer in 40 mL distilled water. Five additional horticultural compositions were then made from this stock horticultural composition by diluting aliquots of the 25% stock horticultural composition into 18%, 10%, 5%, 1% and 0.1% solutions. 2 mL of each concentration of horticultural composition was prepared and added to an Erlenmeyer flask. A control flask included 2 mL of distilled water. Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled with Bachman's brand Garden Soil. 0.25g of K-Gro Sunny Lawn seed mixture was then sprinkled evenly on the surface of the soil in each pot. 2 mL of each horticultural composition, as well as one control (0%) solution, was applied uniformly on top of the seeds of a respective pot. The pots were left in the greenhouse until the grass seedlings emerged. No further water or nutrients were added to any pot. Thus, this example is comparable to Example 13, with the difference being in the amount of horticultural composition applied to the pots. This example used 2 mL, rather than 4 mL, of the horticultural composition per test pot. C. Results

Although the 0.1% horticultural composition test pot had a few seeds emerge, the emergence rate in all test pots was very low.

Example 15. Applying the Horticultural Compositions to Test Pots in which Grass Seeds are Incorporated

A Preparation of Horticultural Compositions

A 25%> by weight stock horticultural composition of the amphoteric polymer of Example 1 was made by dissolving 10.0 g of the amphoteric polymer in

47 40 mL distilled water. Five additional horticultural compositions were then made from this stock horticultural composition by diluting aliquots of the 25%) stock horticultural composition into 18%, 10%, 5%, 1% and 0.1 % solutions in Erlenmeyer flasks. A control flask containing only distilled water was also prepared.

I Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled with Bachman's brand Garden Soil. 0.23g of K-Gro Sunny Lawn seed mixture was then sprinkled evenly on the surface of the soil in each pot. About 1/16th of an inch of soil was then added to the pots to cover the seeds. 2 mL of each horticultural composition, as well as one control (0%) solution, was applied uniformly over the soil in a respective pot. No further water or nutrients were added to any pot. C. Results

The emergence rate in all test pots was very low

Example 16. Horticultural Compositions comprising Grass Seeds A Preparation of Horticultural Compositions

A 25% by weight stock horticultural composition was made by dissolving 10 g of the amphoteric polymer of Example 1 (EMA+dimethylaminoethoxy ethanol) in 40 mL of distilled water. Five additional horticultural compositions were then made from this stock horticultural composition by diluting the stock horticultural composition into 18%, 10%, 5% 1%> and 0.1% solutions. 4 mL of each concentration of horticultural composition was then added to respective Erlenmeyer flasks. A control flask included 4 mL of distilled water.

0.23 g of K-Gro Sunny lawn seed mixture was then added to each flask, including a control flask containing 4 mL of distilled water. The flasks were shaken to ensure that the seeds were coated in the horticultural compositions (or control solution) and subsequently allowed to sit for 5 minutes.

48 B_ Application of the Horticultural Compositions to a Substrate

Seven 2x2 inch pots were filled about 3/4 full with Bachman's brand Garden soil Each of the horticultural compositions (the 25% stock solution, 18%, 10%, 5% 1% and 0 1% solutions) as well as the control solution, were then added to separate pots and spread over the surface of the potting soil by hand

Approximately 1/16th of an inch of soil was then added to the pots, i e , to cover the seeds, followed by 40 mL of distilled water being applied to the surface of the soil in each pot C Results Initial emergence of the grass seedlings was approximately equivalent in all test pots, with the exception that the grass seedlings in the 5% horticultural composition test pot exhibited a slightly more rapid emergence and the grass seedlings in the 25% horticultural composition test pot exhibited a slightly slower emergence However, as time passed, the grass seedlings in the control test pot did not grow as quickly as the grass seedlings in the 5-25%> horticultural composition test pots

At the end of the experiment, the grass seedlings in the 5% horticultural composition test pot were twice as dense as the grass seedlings in the control test pot The grass seedlings in the 5%> horticultural composition test pot were also the tallest of the grass seedlings as compared to all other test pots The grass seedlings in the 5-25% horticultural composition test pots lasted 14 days before the onset of wilting, whereas the grass seedlings in the control test pot began wilting at 7 days The results of this Example are further illustrated by Figures 10 and 11

Example 17. Horticultural Compositions comprising Grass Seeds

A_ Preparation of Horticultural Compositions

Three 90 mL horticultural compositions of the amphoteric polymer of Example 3 were made at weight concentrations of 5%>, 10% and 18% in water A

49 90 mL aliquot of distilled water (0% solution) for use as a control was also set aside. 90 mL of each concentration of horticultural composition, including the 0% control solution, was then added to respective Erlenmeyer flasks.

6.04 g bluegrass seed (purchased from Leitner's, Minneapolis, MN) was then added to each flask. The flasks were shaken to ensure that the seeds were coated with the horticultural compositions (or control solution) and subsequently allowed to sit for 5 minutes.

B, Application of the Horticultural Compositions to a Substrate

A 10.5 x 20 inch container was filled about 3/4 full with Bachman's brand Garden soil. A cardboard partition was inserted into the container in a manner that resulted in the container being divided into four 5.25 x 5 inch partitions. Each of the horticultural compositions (18%, 10% and 5% solutions) as well as the control were then added to a separate partition and spread over the surface of the potting soil by hand. Approximately l/16th of an inch of soil was then added to the pots, i.e., to cover the seeds, followed by 300 mL of distilled water being applied to the surface of the soil in each pot. No other water or nutrients were added to the pots.

C. Results

Initial emergence of the grass seedlings was approximately equivalent in all test pots; with the exception that the grass seedlings in the control test pot exhibited a slightly more rapid emergence rate. However, as time passed, the grass seedlings in the 10% horticultural composition test pot surpassed the growth of the grass seedlings in all other test pots. Additionally, the grass seedlings in the 10% horticultural composition test pot lasted about 5 days longer than the grass seedlings in the control test pot before the onset of wilting. The grass seedlings in the 18% horticultural composition test pot had a poor emergence rate and died sooner than the grass seedlings in the other test pots.

The data from Examples 11-17 shows that a particularly effective embodiment of the invention comprises coating grass seeds with an aqueous

50 solution preferably comprising 5 to 25% by weight of the amphoteric polymer of the present invention. The examples further show that the coated seeds must be sown with enough water for proper germination to occur. If too little water is present, the emergence and growth rates will be low. If too much water is used, mold will develop. Generally, using 2 mL to 15 mL, preferably about 4 mL of solution per 4 in² of potting area was effective when planting coated seeds. The results of these examples also shows that grass grew best when coated seeds are topically applied onto a growing medium, or when the coated seeds are coated with a thin layer of dirt. Other embodiments of this invention will be apparent to those skilled in the art upon consideration of this specification or from practice of the invention disclosed herein. Various omissions, modifications, and changes to the principles and embodiments described herein may be made by one skilled in the art without departing from the true scope and spirit of the invention which is indicated by the following claims.

51

Claims

WHAT IS CLAIMED IS

1 A horticultural composition for promoting growth and viability of a horticulturally viable substrate, comprising at least one amphoteric polymer having cationic functionality in a first pH range, zwitterionic functionality in a second pH range, and anionic functionality in a third pH range

2 The horticultural composition of claim 1, further comprising a horticulturally effective amount of at least one nutrient

3 The horticultural composition of claim 2, wherein the plant treatment agent is selected from the group consisting of a fertilizer, a micronutrient, a pesticide, a herbicide, a game repellent, a nematocide, a fungicide, a growth retardant, a germination promoter, and combinations thereof

4 The horticultural composition of claim 1, further comprising an amount of water sufficient to result in the horticultural composition being coatable or sprayable onto a horticulturally viable substrate

5 The horticultural composition of claim 4, further comprising at least 10 parts by weight of water per 100 parts by weight of the amphoteric polymer

6 The horticultural composition of claim 5, further comprising 10 to 50,000 parts by weight of water per 100 parts by weight of the amphoteric polymer

7 The horticultural composition of claim 1, further comprising a horticulturally viable substrate bearing a coating comprising the amphoteric polymer

52

8. The horticultural composition of claim 7, wherein the coating is coated onto at least a portion of the surface of the horticulturally viable substrate.

9. The horticultural composition of claim 8, wherein the coating coats substantially the entirety of the horticulturally viable substrate.

10. The horticultural composition of claim 8, wherein the horticulturally viable substrate comprises at least one viable seed.

11. The horticultural composition of claim 8, wherein the horticulturally ^• viable substrate is a seedling or plant.

12. The horticultural composition of claim 1, wherein said composition is a growing medium.

13. The horticultural composition of claim 12, wherein the growing medium further comprises at least one additional soil medium in addition to the amphoteric polymer.

14. The horticultural composition of claim 12, wherein the amphoteric polymer is present in an amount effective to increase the water holding capacity of the growing medium.

15. The horticultural composition of claim 12, wherein the growing medium comprises 0.1 to 100 weight percent of the amphoteric polymer.

16. The horticultural composition of claim 12, wherein the growing medium comprises 0.5 kg to 100 kg of the amphoteric polymer per square meter of planing area.

53

17. The horticultural composition of claim 1, wherein the amphoteric polymer comprises a plurality of pendant carboxylate moieties and a plurality of pendant ammonium moieties.

18. The horticultural composition of claim 17, wherein the molar ratio of carboxylate moieties to ammonium moieties is about 1 : 1 and the amphoteric polymer comprises substantially no separate counterions complexed with the carboxylate and ammonium moieties.

19. The horticultural composition of claim 17, wherein the amphoteric polymer has a weight average molecular weight in the range from about 1,000 to about 1.8 million, and wherein the equivalent weight of the carboxylate moieties is in the range from about 170 to about

900,000 g/eq and the equivalent weight of the ammonium moieties is in the range from about 170 to about 900,000 g/eq.

20. The horticultural composition of claim 17, wherein at a substantially neutral pH, the amphoteric polymer comprises a plurality of anionic first chain segments of the formula:

( C )

Xi C = O

I

O^θ

and a plurality of cationic second chain segments of the formula:

( C ,

X₂

54 wherein each of X_t and X₂ is independently a single bond or a divalent linking group; cationic counterion and A^θ is a positively charged, ionic moiety comprising a nitrogen atom covalently linked to four moieties with the proviso that no more than one of said four moieties is hydrogen.

21. The horticultural composition of claim 20, wherein the first chain segments further comprise a separate cationic counterion complexed with the carboxylate moiety and a separate anionic counterion complexed with the ammonium moiety.

22. The horticultural composition of claim 20. wherein the ratio of the number of first chain segments to the number of second chain segments is in the range from about 100: 1 to about 1 : 100.

23. The horticultural composition of claim 22, wherein the ratio of the number of first chain segments to the number of second chain segments is in the range from about 20: 1 to about 1 :20.

24. The horticultural composition of claim 23, wherein the ratio of the number of first chain segments to the number of second chain segments is about 1 : 1.

25. The horticultural composition of claim 20, wherein Xi is a single bond and X₂ is a divalent linking group of the formula:

C=O

I γ₂

χ₃

55 wherein X₃ is a divalent linking group selected from an alkylene moiety, a perfluorinated polyether moiety, a polyether moiety, a polyester moiety, a polyurethane moiety, a polycarbonate moiety, and combinations thereof; and Y₂ is selected from -O-, -NH-, -S-, and -NR₃-, wherein R₃ is a monovalent moiety other than H or an acid group.

26. The horticultural composition of claim 25, wherein X₃ is an alkylene moiety of 1 to 20 carbon atoms.

27. The horticultural composition of claim 25, wherein X₃ is a polyether moiety having a molecular weight in the range from about 44 to about 2,500.

28. The horticultural composition of claim 20, wherein A^θ is:

H

I a — N — Rj

R₂ wherein each of Ri and R₂ is independently a monovalenc moiety other than H or an acidic moiety.

29. The horticultural composition of claim 28, wherein Ri and R₂ are each independently an alkyl group of 1 to 20 carbon atoms.

30. The horticultural composition of claim 20, wherein A^θ is:

H

/ — S^θ \ Ri wherein Ri is a monovalent moiety other than H or an acidic group.

56

31. The horticultural composition of claim 30, wherein A^θ is

H

I ^θ

— P— R_!

I

R₂ wherein each of Ri and R₂ is independently a monovalent moiety other than hydrogen.

32. The horticultural composition of claim 20, wherein at least a portion of the first and second chain segments are covalently linked to each other such that the amphoteric polymer comprises a plurality of chain segments of the formula:

( C C )

Xi X₂

I I

O=C A^θ

O^θ

33. The horticultural composition of claim 20, wherein at least a portion of the first and second chain segments are covalently linked to each other and the amphoteric polymer further incorporates copolymerized units derived from ethylene such that the amphoteric polymer comprises a plurality of chain segments of the formula:

( C C C C )

I I

Xi x₂

O=C C=O

O^θ A^θ

34. The horticultural composition of claim 32, wherein the first chain segments further comprise a separate cationic counterion complexed with the

57 carboxylate moiety and a separate anionic counterion complexed with the ammonium moiety.

35. The horticultural composition of claim 33, wherein the first chain segments further comprise a separate cationic counterion complexed with the carboxylate moiety and a separate anionic counterion complexed with the ammonium moiety.

36. The horticultural composition of claim 17, wherein the amphoteric polymer comprises a plurality of chain segments of the formula:

( C C )

O=C C=O

O^θ O

CH₂

H₃C— N— CH₃

I a H

37. The horticultural composition of claim 20, wherein the amphoteric polymer further incorporates a plurality of chain segments derived from N,N' — methylenebisacrylamide.

38. The horticultural composition of claim 20, wherein the amphoteric polymer comprises a sufficient amount of the carboxylate and ammonium moieties such that the amphoteric polymer is water soluble in a pH range from 2 to 11.

39. A method of promoting plant growth and viability, comprising the steps of providing a horticultural composition comprising a horticulturally

58 therapeutic amount of at least one amphoteric polymer and applying the horticultural composition in functional proximity to a horticulturally viable substrate.

40. The method of claim 39, wherein the horticultural composition further comprises an amount of water sufficient to result in the horticultural composition being sprayable or coatable.

41. The method of claim 40, wherein the aqueous horticultural composition comprises 100 parts by weight of water and 0.1 to 100 parts by weight of the amphoteric polymer.

42. The method of claim 41, wherein the horticultural composition comprises 100 parts by weight of water and 0.1 to 50 parts by weight of the amphoteric polymer.

43. The method of claim 40, wherein the applying step comprises coating the horticulturally viable substrate with the horticultural composition.

44. The method of claim 40, wherein the horticulturally viable substrate is a seed.

45. The method of claim 40, wherein the horticulturally viable substrate is a seedling or plant.

46. The method of claim 45, wherein the applying step comprises dipping at least a root of the seedling plant into the horticultural composition.

59

47. The method of claim 45, wherein the applying step comprises coating the horticultural composition onto an above-ground portion of the plant.

48. The method of claim 40, wherein the applying step comprises spraying the horticultural composition onto a growing medium.

49. The method of claim 40, wherein the applying step comprises intermixing the horticultural composition into a growing medium.

60