Industrial Technology Research Institute

Chien-Chun Yang

I-Horng Pan

Suey-Sheng Kao

Mei-Hueih Chen

Yeong-Sheng Tsai

Ching-Chou Tzeng

This invention relates to a novel method for preparing pesticide microcapsules in which the release rate and the release period of the pesticide are controlled. A process has been discovered for encapsulating a trace amount of pesticide with a urea-formaldehyde resin, mechanically stirring the resin in the presence of vegetable oil and the pesticide and reacting the mixture under suitable conditions to form a desired pesticide microcapsule.

Preparation of pesticide microcapsule

A particulate controlled-release pesticide composition having a pesticide encapsulated in a polymer matrix of starch-borax-urea and method of preparation and use thereof is provided. The release rates and release duration of the pesticide compositions are controllable by adjusting the urea content in the compositions. The pesticide composition is preparable by admixing starch, pesticide, urea and water together to form a mixture and agitating the same at a temperature sufficient to gelatinize the mixture and to disperse the mixture. Borax is then added to the mixture in an amount effective to convert the mixture into a rubbery mass. The rubbery mass is then comminuted into small particles, in the presence of added starch, and dried.

Controlled-release pesticides and methods for preparation and use thereof

A biocidal formulation with improved resistance to ultraviolet rays comprising: (a) an appropriate biocide which is Bacillus thuringiensis; (b) an anti-ultraviolet agent selected from the group consisting of 2-(2-H-benzotriazole-2-yl)-phenol and their derivatives represented by the following formula: ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from the group consisting of alkyl, aryl, and alkylaryl groups; (c) pre-gelatinized starch; and (d) natural starch, the biocide, the anti-ultraviolet agent, the pre-gelatinized starch and the natural starch are mixed then baked at 60.degree.-90.degree. C. to form the biocidal formulation.

Anti-ultraviolet biocidal composition

Biocidal formulations prepared by: (a) blending predetermined amounts of pre-gelatinized starch, natural starch, biocide such as Bacillus thuringiensis and water to form a mass; (b) drying said mass by heating prepared by with a hot roller at temperatures between 50.degree. and 100.degree. C., preferably between 60.degree. and 90.degree. C., to form a dried mass; and (c) crushing the dried mass to form the final product having the shape of flakes with a diameter preferably less than about 900.mu.. With the method disclosed in the present invention, the process time can be reduced from 24 hours in the prior art to no more than 30 minutes, preferably about 3 to 15 minutes. The present invention represents substantial economic benefits as well as reductions of potential health risks as a result of the reduced contact by operators with biocides during the preparation process.

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Hsin-Chu, Taiwan

Chien-Chun Yang