Seed coating composition

Abstract

The invention is directed to a seed coating composition containing a polymeric binder, a filler and a fibrous material. The seed coating composition can be formed by combining an aqueous composition pre-blend which contains a polymeric binder with a powder pre-blend which contains a filler and a fibrous material. The polymeric binder preferably contains polyvinylpyrrolidone, the filler preferably contains talc and the fibrous material preferably contains cellulose fibers.

Claims

1. A seed coating composition comprising: a range from greater or equal to 70 to less than 95% by weight of polyvinylpyrrolidone, where the polyvinylpyrrolidone has a molecular weight in a range of 9,000-11,000; a range from greater or equal to 5 to less than 30% by weight of a polymeric binder other than polyvinylpyrrolidone; a filler comprising talc; and a fibrous material comprising cellulose fibers having a median volume particle diameter value D(v,0.5) in a range 10-120 μm.

2. The seed coating composition according to claim 1 wherein the polymeric binder other than polyvinylpyrrolidione comprises at least one polymer selected from the group consisting of polyvinyl acetate, vinyl acetate copolymer, polyvinyl alcohol and polyacrylate.

3. The seed coating composition according to claim 1 comprising less than 20% by weight of water.

4. The seed coating composition according to claim 1, wherein the filler is in particle form and wherein the ratio of filler particles to fibrous material is 0.5 to 15.0:1 by weight.

Description

EXAMPLE 1

(1) Pre-blend formulations were prepared according to Table 1.

(2) TABLE-US-00001 TABLE 1 Aqueous Composition Pre-Blend and Powder Pre-Blend Formulations Aqueous Composition Pre-Blend (wt. %) water 43.12 rheology additive 0.2 defoamer 0.04 biocide 0.19 polyvinylpyrrolidone 30.0 polyvinyl alcohol (15 wt. %) 12.0 vinyl acetate-Veova copolymer (50 wt. %) 4.0 colored pigment 5.45 mica 5.0 Powder Pre-Blend (wt. %) cellulose fiber 20.0 talc 80.0

(3) A PPP (plant protection products) cocktail was used containing 20.77% Cruiser 5FS (insecticide, ex Syngenta) and 6.0% Maxim Quattro (fungicide, ex Syngenta). Corn seeds were coated with a mixture of 0.7 wt. % PPP cocktail, 30.5 wt. % aqueous composition pre-blend and 68.8 wt. % powder pre-blend; the application rate being such that 200 g dry film coating per kg seed was applied. The coated seeds were dried in warm air for 10 minutes.

EXAMPLE 2

(4) The rate of drying of the seeds produced in Example 1 was measured by using a cotton indicator. The coated seeds, after exiting the coater, were collected in a flat tray and a timer was activated. The drying was checked every 10 seconds by placing a fresh cotton indicator at a new seeds' surface in the seed tray each time. The moment there was no sign of color transfer on the cotton indicator from the seed, the timer was stopped and the time was recorded

(5) Clumping/bridging of seeds takes place when wet seeds exiting out of the coater are collected in the storage hopper and compacted by oncoming seeds. This presents a challenge to the seed treatment facility in terms of equipment blocking, labor and time.

(6) There was no color transfer on the cotton indicator after 10 seconds, the coated corn seeds were immediately dry to the touch, non-tacky and showed no clumping.

EXAMPLE 3

(7) 100 g of the coated corn seeds produced in Example 1 were submitted to a 4-minute Heubach test in duplicate, and the results averaged to a total amount of dust-off per 100,000 seeds. In the case of corn, the dust reference values that were developed by ESA for treated corn seeds is a maximum of 0.75 g of dust per 100,000 seeds. Dust level was reduced to 0.12 to 0.14 g per 100,000 seeds when using the coated corn seeds of Example 1. Abrasion on the corn seeds was visually observed after the dust experiment in the Heubach apparatus. The abrasion score is a visual quantification of the quality of seeds after subjecting them to 4 minutes in the Heubach apparatus closely simulating handling conditions in the industry. The abrasion score was allocated from 1 (high abrasion resistance/good quality seeds) to 5 (low abrasion resistance/poor quality seeds). The coated corn seeds had an abrasion score of 1.

EXAMPLE 4

(8) The flow of coated seeds is important at the seed treating facility as well as at the farm whilst going through the planter. The lower the friction between the seeds, the better the efficiency at various stages. Typically, the addition of PPPs and traditional film-coats to corn seeds slows down the flow of seeds considerably, which is not a desired characteristic. For testing the flow of the coated corn seeds produced in Example 1, 1 kg of seeds were placed in a funnel fitted with a stopper. The stopper was opened and timer started simultaneously. The time taken for the last seed to exit the funnel was recorded as the flow rate in (s/kg). The coated corn seeds had a flow rate of 6.39 s/kg, compared to uncoated corn seeds which had a flow rate of 6.18 s/kg, i.e. the coated corn seeds allowed flow almost as fast as untreated corn seeds.

(9) The above examples illustrate the improved properties of the seed coating composition and coated seeds according to the present invention.