Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-12-27
2002-12-10
Kopec, Mark (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S224000, C510S349000, C510S361000, C510S441000, C510S443000, C510S444000, C510S446000, C510S452000, C510S477000, C510S533000
Reexamination Certificate
active
06492320
ABSTRACT:
The present invention relates to pellets which disintegrate rapidly in aqueous media and which have sufficient mechanical strength to withstand breakage during manufacture, storage, shipping and handling. More particularly, the invention is directed to multifunctional aids for preparing pellets.
The term “pellet” refers to any solid formulation, including but not limited to, tablets, bricks, briquettes, bars, granules, granulates, co-granulates, balls, or blocks. Pellets are well known in the fields of medicine, food science, agriculture, consumer products and more recently they are being used in detergent applications. Pellets offer certain advantages over granular compositions. Pellets are non-dusting, do not require measuring, take up less space because they are compressed and the ingredients that make up a pellet do not separate during transit and storage. Pellets also allow the separation of incompatible ingredients within different layers of the pellet body. Pellets are generally made by compressing or compacting a solid composition which includes one or more active components and various additives or ingredients.
An ongoing problem associated with pellets is the difficulty in providing pellets which have adequate mechanical strength when compacted, yet disintegrate and dissolve quickly when added to an aqueous system. One approach has been to use an additive in preparing a pellet. The problem, however, has proved especially difficult due to the relative rates of dissolution or disintegration of pellets currently in use as compared with granular compositions. Often, it is necessary to compromise between the speed of disintegration of the pellet at the time of use and the strength of handling the pellet before use. In the manufacturing process, a balance must be maintained between a pellet compaction pressure which is, on the one hand, high enough to ensure that the pellets are well formed and do not fracture and/or crumble during transport and storage, and a pellet compaction pressure which is, on the other hand, low enough to achieve an appropriate solubility/disintegration profile. A single material or pellet aid that can be added to ingredients that constitute a pellet would be of significant utility, particularly if the pellet aid possessed a variety of useful functions, in other words a multifunctional pellet aid. The term multifunctional in the present invention refers to a granulated, polymeric pelleting aid which functions for example as a binder, a disintegrating agent and a wicking agent in one solid material.
U.S. Pat. No. 5,916,866 discloses a process for making compacted detergent tablets comprising spraying a coating of a water-soluble organic polymer binder onto the exterior of particles of detergent compositions including a detergent actives and detergent builders. European publication EP 0 896 052 A1 discloses detergent tablets with improved handling strength and swift dissolution which comprise a non-gelling binder and a coating. Examples of non-gelling binders are taken from the prior art but suitable coating materials are dicarboxylic acids for example selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid and mixtures thereof U.S. Pat. No. 5,883,061 teaches polymeric tablet binders which comprise (meth)acrylic acid, maleic anhydride, alkyl (meth)acrylates, alkylhydroxy (meth)acrylates or styrene monomers in polymerised form. The polymeric binders have a Tg ranging from +40 to +120° C. and a molecular weight of from 10,000 to 120,000. U.S. Pat. No. 5,360,567 discloses a detergent tablet coated with a polymeric binder, namely polyethylene glycol, which is also capable of acting as a disintegrant by disrupting the structure of the tablet when the tablet is immersed in water. The '567 patent, however, teaches that it is highly advantageous for the binder/disintegrant to coat or envelop the detergent matrix particles rather than to be simply mixed with them. Clearly, alternative pellet aids are still sought, pellet aids which have more than one type of functionality and which provide pellets having improvements in tablet strength and the rate of disintegration in aqueous media. A single, multifunctional material that can aid in the production of a compacted pellet, a pellet which disintegrates rapidly in aqueous media and which has sufficient mechanical strength to withstand breakage during storage, shipping and handling, would be of substantial utility.
The inventors have discovered a granulated, polymeric pelleting aid which surprisingly functions as a binder, a disintegrating agent and a wicking agent in one solid material. The present invention provides novel pellet aids in the form of granulated compositions used in the processing of pellets by direct compression. Pellets processed with such solid compositions have sufficient mechanical strength to be handled and stored without breakage, yet dissolve rapidly upon contact with water. The pellet aid can be incorporated at any stage of the pelleting process prior to pellet compaction and, optionally the pellet aid can be co-granulated with other functional additives.
In a first aspect of the present invention, there is provided a granulated composition as a pellet aid for binding one or more ingredients and then compacted into a pellet, the pellet having sufficient mechanical strength and rapidly disintegrating when contacted with an aqueous system, the composition including: (a) 20 to 80% by weight of one or more binders, wherein at least one binder is a solution, suspension or emulsion polymer having a Tg ranging from −20° C. to +95° C.; (b) 0 to 40% by weight of one or more inorganic solids; and (c) 10 to 80% by weight of one or more organic solids, wherein the granulated composition is present in an amount from 0.25 to 5% by weight of the total weight of the pellet, the granules having a particle size ranging from 100 &mgr;m to 3000 &mgr;m.
In a second aspect of the present invention, there is provided a process for preparing a multifunctional pellet aid which includes the steps of: (a) premixing 0 to 40% by weight of one or more inorganic solids and 10 to 80% by weight of one or more organic solids; (b) spraying 20 to 80% by weight of one or more solution, suspension or emulsion polymers having a Tg ranging from −20° C. to +95° C. on to the premixed solids to achieve a particle size ranging from 100 &mgr;m to 3000 &mgr;m.
In a third aspect of the present invention, there is provided a process for preparing a multifunctional pellet aid which includes the steps of: (a) preparing a slurry of 0 to 40% by weight of one or more inorganic solids and 20 to 80% by weight of one or more solution, suspension or emulsion polymers having a Tg ranging from −20° C. to +95° C.; and (b) spraying the slurry on to 10 to 80% by weight of one or more organic solids to achieve a particle size ranging from 100 &mgr;m to 3000 &mgr;m.
In a fourth aspect of the present invention, there is provided a process for preparing a solid pellet having high mechanical strength, which can withstand storage and handling without fracturing, and which rapidly disintegrates upon contact with an aqueous system comprising the steps of: (a) mixing 90 to 99.75% by weight of a plurality of ingredients and 0.25 to 10% by weight of a granulated, multifunctional pellet aid composition, wherein the pellet aid comprises (i) 20 to 80% by weight of one or more binders, wherein at least one binder is a solution, suspension or emulsion polymer having a Tg ranging from −20° C. to +95° C.; (ii) 0 to 40 % by weight of one or more inorganic solids; and (iii) 10 to 40% by weight of one or more organic solids, the particle size of pellet aid ranging from 100 &mgr;m to 3000 &mgr;m; (b) compacting the mixture of ingredients and pellet aid to form a pellet.
The solid pellet aid composition usefully employed in accordance with the present invention includes one
Chia Wen H.
Guo Hailan
Schwartz Curtis
Johnson Stephen E.
Kopec Mark
Mruk Brian P.
Rohm and Hass Company
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