Plant protecting and regulating compositions – Fertilizers with insecticide – fungicide – disinfectant – or...
Reexamination Certificate
2001-02-28
2003-12-02
Levy, Neil S. (Department: 1616)
Plant protecting and regulating compositions
Fertilizers with insecticide, fungicide, disinfectant, or...
C071S064070, C424S421000, C514S772400, C514S782000, C514S783000, C523S123000, C523S132000
Reexamination Certificate
active
06656882
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to controlled release products such as controlled release fertilizer products. More particularly, it relates to coated products in particulate form which are structured to provide release profiles wherein initial release of active ingredients such as fertilizer nutrients therefrom is suppressed or inhibited for a predetermined period and longevity for release the active ingredients is within a period of time of 60 days or less after the time of application. The invention further relates to the use of such products, particularly, as potting soil starter fertilizers and to processes for producing particulate products exhibiting the desired release profiles.
2. Description of Related Art
The use of controlled release products such as controlled release fertilizer compositions to provide nutrients in growing media has been well known for a long period of time heretofore. Also, it has been known heretofore that the presence of additional nutrients in growing media may be beneficial depending on when these additional nutrients are made available to the plants growing in these media. However, the availability of too many nutrients can be detrimental to the plants. Furthermore, the presence of too much available nutrients can be considered not only an inefficient use of fertilizer, but also a threat to the environment.
Thus, it has been recognized previously that delivery of the correct amount of nutrients at the correct time is crucial for growing plants. However, with conventional water-soluble fertilizers optimal delivery of nutrients can only be achieved by employing very labor intensive methods. Alternatively, correct delivery of nutrients for nutrient uptake by plants can be achieved by modification of the fertilizer products such as by chemical means to reduce the solubility of the nutrients, or by physical means such as by coating or encapsulating the fertilizer compositions.
Likewise, it has been recognized heretofore that the controlled release of other water soluble core materials such as insecticides, herbicides, fungicides, pheromones, biostimulants, growth regulators and the like within a predetermined time period would be advantageous from a utilitarian and commercial standpoint.
With specific regard to coated or encapsulated fertilizers, such products are known to be very effective sources for providing controlled release of nutrients for growing of plants. In such products, the nutrients are released at controlled rates, resulting in sustained feeding of plants treated with the fertilizer. As a result, a single application of these so-called controlled release fertilizers (CRFs) can provide the necessary nutrients that would take multiple applications of soluble fertilizers.
The types of coatings that may be applied to soluble core materials such as fertilizer particles to produce CRFs include impermeable coatings, impermeable coatings with tiny pores, and semi-permeable coatings. Typical examples of CRFs with an impermeable coating are sulfur-coated fertilizers such as those disclosed in U.S. Pat. No. 4,636,242. With such sulfur-coated fertilizers, the release of nutrients from the sulfur-coating occurs by diffusion through imperfections in the sulfur coating and through coating breakdown followed by a relatively rapid release of nutrients.
Polymer/sulfur-coated fertilizers such as those disclosed in U.S. Pat. No. 5,405,426 and U.S. Pat. No. 5,219,465 are hybrid products that utilize a primary or inner coating of sulfur with a secondary or outer polymer coating. The nutrient release mechanism in such products results from a combination of water diffusion through the polymer coating and subsequently water penetration through the defects in the sulfur coating. Thus, the release properties of such polymer/sulfur-coated fertilizers are more uniform, and approach those of polymer-coated fertilizers, but at a reduced cost.
Polymer-coated fertilizers are considered to present a more technically advanced approach for controlling the release characteristics. Polymer coatings for soluble nutrient sources may be either impermeable coatings with tiny pores or semi-permeable coatings. The addition of a special surfactant to an impermeable coating material results in microscopic pores. Water diffuses through these pores into the core fertilizer granule dissolving the nutrients. The amount of surfactant in the coating determines its porosity and as a result its release characteristics (typical examples of these CRF products are sold with the trademark Nutricote®). It should be noted that, although these products cover a wide time period of release (from 40 days up to 12 months), these type of CRFs have the disadvantage that they always require the addition of a special compound in order to achieve the desired release profiles.
Semi-permeable polymeric coatings used for coating CRFs can be categorized as based either on thermoplastic (such as disclosed in U.S. Pat. Nos. 4,019,890 and 5,186,732) or on thermosetting (such as disclosed in U.S. Pat. Nos. 3,223,518 and 4,657,576, and sold with the trademark Osmocote®) resins. The presence of a polymeric coating on CRFs allows for a rather uniform and consistent nutrient release, provided that the barrier properties of the coating are sufficient. In such products, the release essentially is determined by the coating thickness alone. With some polymer-coated fertilizers, a relatively high initial rate of nutrient release is observed within the first 24 hours after application which is followed by a decreasing nutrient release rate for an extended period thereafter.
The application of a second polymeric coating may compensate for the high initial release rate, thus resulting in CRF products exhibiting delayed release (such as disclosed in U.S. Pat. No. 5,652,196). The most technically advanced state of the art in CRFs with delayed release characteristics comprises single layer coated products (such as disclosed in U.S. Pat. No. 5,993,505). The latter compositions are structured to provide a cumulative release of nutrients of less than 10% of the total nutrients within 30 days after exposure to moisture.
A general characteristic of the presently available commercial CRF products with semi-permeable coatings, such as the Osmocote® type products, is that these products provide a controlled release of nutrients for relatively long periods of time. Although the release rate of the nutrients out of the CRF products depends on several factors, the only one presently being used in practice to control the length of the release is the amount of coating. The generally accepted method of producing CRF products with different release periods is by using a coating material with high barrier properties at varying coating amounts or thicknesses.
The CEN (Comité Européen de Normalisation) TC 260/WG 4/Task Force (hereinafter referred to as “the CEN TC 260) has provided a standard definition for controlled or slow-release fertilizers. Under that definition, a product may be considered a CRF if the release profile of the product meets the following criteria:
(1) No more than 15 weight percent (wt. %) of core material is released from the fertilizer product within the first 24 hours after application of the product, at ambient temperature;
(2) No more than 75 weight percent (wt. %) of core material is released from the fertilizer product within 28 days after application of the product, at ambient temperature; and
(3) At least 75 weight percent (wt. %) of core material is released from the fertilizer product within a predetermined release time after application, at ambient temperature.
With regard to criterion 1 above, it should be noted that this standard is applied to all of the controlled release products of the present invention in defining the suppressed or inhibited initial release characteristics thereof. Concerning criterion 3 above, it should be further noted that for purposes of the present invention, the predetermined release time after application, at ambient tempera
Haas-Schrijen Saskia
Terlingen Johannes Gijsbertus Antonius
Tijsma Edze Jan
Vriesema Hein Herman
Day Jones
Levy Neil S.
OMS Investments, Inc.
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