Dual layer tablet, method of making and use thereof

Abstract

A method for treating a recirculating water system which comprises introducing into said water system a multifunctional, multilayer tablet, wherein the multilayer tablet comprises a fast dissolving layer and a slow dissolving layer, wherein said fast dissolving layer releases a combination of active ingredients including a member selected from the group consisting of lithium hypochlorite, calcium hypochlorite, trichloroisocyanuric acid (TCCA), anhydrous sodium dichloroisocyanurate, sodium persulfate, potassium persulfate, potassium monopersulfate, sodium monopersulfate, and mixtures thereof, and at least one of a clarifier, chelating agent, sequesterant, algaestat, water softener, algaecide, corrosion inhibitor, scale inhibitor, flocculent, disintegrant, dispersant, colorant, dissolution control agent, fragrance, or surfactant and, wherein said slow dissolving layer includes a member selected from the group consisting of trichloroisocyanuric acid (TCCA), calcium hypochlorite, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH), 1,3-dichloro-5-ethyl-5-methylhydantoin (DCEMH), 1,3-dibromo-5-ethyl-5-methylhydantoin (DBEMH), 1-bromo-3-chloro-5-methyl-5-ethylhydantoin (BCEMH), and mixtures thereof, and at least one of a clarifier, chelating agent, sequesterant, algaestat, water softener, algaecide, corrosion inhibitor, scale inhibitor, flocculent, disintegrant, dispersant, colorant, dissolution control agent or surfactant.

Description

INTRODUCTION AND BACKGROUND [0001] The present invention relates to dual layer tablets for the treatment of water to enhance and improve the properties thereof. In a further aspect, the present invention relates to the methods of making the dual layer tablets and the uses thereof. [0002] In a water system that includes recreational applications (i.e. pools or spas), industrial water applications (i.e. cooling towers) or household applications (i.e. bathroom toilets), the purification of the water and the system containing the water are usually done by using a wide variety of biocides, sanitizers, disinfectants, dispersants, or surfactants. All the products are either in a liquid or solid form. [0003] One of the challenges for these types of products is that the tablets must have good tablet strength, good tablet quality and show no sign of fracture, swelling or breakage under normal storage conditions. The tablets must also readily dissolve and release the active ingredients to prov...