COATED AGRICULTURAL PESTICIDE GRANULES, PROCESS FOR PREPARING THE SAME, AND USE OF THE SAME
申请人:CHISSO CORPORATION
公开号:EP0848906A1
公开(公告)日:1998-06-24
The present invention provides a coated granular pesticide comprising a granular pesticide, which comprises at least one hardly water-soluble active ingredient and at least one water-swelling substance, and a thermoplastic resin-based film which covers the surface of the granular pesticide; a method for producing the same; and applications thereof. It is preferred to incorporate, into the film, a surfactant, inorganic powder insoluble or hardly soluble in water, water-absorbing and/or water-soluble polymer fine powder, a thermosetting resin, or a biodegradable polymer insoluble or hardly soluble in water, or a combination thereof. The coated granular pesticide of the present invention can externally release the hardly water-soluble active ingredient according to the following mechanism, due to the combined effects of the thermoplastic resin as the film-forming component and the water-swelling component as the core component. The water-swelling substance absorbs the water present in the exterior of the coated granular pesticide, which gradually penetrates into the granule through the coating film, the granular pesticide containing the water-swelling substance gradually expands, cracks are thus formed on the film after the elapse of a predetermined time, a large amount of water rapidly enters into the granule through the cracks thus formed, the coated granular pesticide is rapidly swollen to thus greatly grow the cracks and to thus rapidly disintegrate the film and the hardly water-soluble active ingredient included in the coated granular pesticide is thus brought into close contact with a large amount of water to externally release the active ingredient. The foregoing components to be incorporated into the film serve to control the disintegration time of the resulting film. The gradual release of the hardly water-soluble active ingredient is initiated after a predetermined time from the application of the coated granular pesticide and therefore, the latter exhibits a desired efficacy depending on a particular crop without being accompanied by any problem of damages of crops from the pesticide and of environmental load.
For instance, the coated granular pesticide of the present invention may directly be applyed on the ground or may be used in the form of a mixture with soil, but preferably the coated granule is used in the form of a substrate for raising seedlings, which may be obtained by admixing with a seedling-support substance having water-holding properties.
本发明提供了一种包衣颗粒状农药,包括颗粒状农药(其中包含至少一种难溶于水的活性成分和至少一种遇水膨胀的物质)和覆盖颗粒状农药表面的以热塑性树脂为基材的薄膜;本发明的生产方法及其应用。最好在薄膜中加入表面活性剂、不溶于水或难溶于水的无机粉末、吸水性和/或水溶性聚合物细粉、热固性树脂或不溶于水或难溶于水的生物可降解聚合物,或它们的组合。由于热塑性树脂作为成膜成分和水膨胀成分作为核心成分的共同作用,本发明的包衣颗粒农药可以按照以下机理从外部释放难溶于水的活性成分。水膨胀物质吸收包衣颗粒状农药外部的水分,水分通过包衣膜逐渐渗入颗粒内部,含有水膨胀物质的颗粒状农药逐渐膨胀,经过预定时间后,包衣膜上形成裂纹、大量的水通过裂缝迅速进入颗粒,包衣颗粒状农药迅速膨胀,使裂缝大大增加,从而使薄膜迅速崩解,包衣颗粒状农药中几乎不溶于水的有效成分与大量的水紧密接触,从外部释放出有效成分。加入薄膜中的上述成分可以控制薄膜的崩解时间。几乎不溶于水的活性成分在施用包衣颗粒杀虫剂后的预定时间后开始逐渐释放,因此,后者可根据特定作物的情况显示出所需的药效,而不会伴随着杀虫剂对作物的损害和环境负荷问题。
例如,本发明的包衣颗粒杀虫剂可以直接施用在地面上,也可以以与土壤混合的形式使用,但包衣颗粒最好以育苗基质的形式使用,育苗基质可以通过与具有保水特性的育苗物质混合获得。