Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-09-22
2003-01-07
Gupta, Yogendra N. (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, C510S452000, C510S477000, C510S533000
Reexamination Certificate
active
06503878
ABSTRACT:
The present invention relates to pellets, particularly those which disintegrate quickly in aqueous media and which are sufficiently strong to withstand breakage during storage, shipping and handling.
By “pellet”, we mean any solid formulation, including but not limited to, tablets, bricks, briquettes, bars, granules, balls, or blocks.
Pellets are well known in the fields of medicine and agriculture and more recently they are being used in detergent applications. Pellets offer certain advantages over granular compositions; they are non-dusting, do not require measuring, take up less space because they are compressed and the ingredients do not separate during transit and storage. However, problems are experienced regarding the dissolution or disintegration of the pellets in use as compared with granular compositions. In the manufacturing process, a balance must be kept between a pellet compacting pressure which is, on the one hand, high enough to ensure that the pellets are well formed and do not crumble during transport and storage, and a pellet compacting pressure which is, on the other hand, low enough to achieve an appropriate solubility/dispersibility profile. It is well known to use an additive to improve pellet dispersability, for example as disclosed in European Patent Application No. 99304428.8, and agents to improve the strength of the pellet so as to avoid the need for high pellet compacting pressure.
Looking specifically at agents which improve the strength of the pellet, GB 983,243 and GB 989,683 describe the use of a water-soluble organic film forming polymer to form on the pellet (briquette) surface a water soluble film which is sufficiently strong to help make detergent tablets resistant to abrasion and accidental breakage, when dry, and sufficiently soluble to help the detergent tablet to disintegrate readily in water. Suitable coating polymers are polyvinyl alcohol and polyvinyl acetate and, to a lesser extent, polyvinylpyrollidone, sodium carboxymethyl cellulose and hydroxypropyl methyl cellulose.
EP-A2-711828 teaches the use of a binder to improve the strength of detergent tablets; preferred binders are selected from polyethylene glycol, polyvinylpyrollidone, and polyacrylates and water soluble acrylate copolymers.
EP-A2-716144 teaches the use of the binders polyethylene glycol, polyvinylpyrollidone, and polyacrylates and water soluble acrylate copolymers in combination with an exterior coating of organic polymer. Suitable coating materials melt between 40 and 80° C. and preferably comprise a copolymer of (meth)acrylic acid and maleic acid or anhydride, or neutralised salts thereof.
EP-A1-896052 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.
Finally, 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 polymer has a Tg of from +40 to +120° C. and a molecular weight of from 10,000 to 120,000.
The aim of the present invention is to provide novel pellets which are strong enough to be shipped, handled and stored without breakage and yet dissolve quickly on contact with water.
Accordingly, the present invention provides a pellet comprising: one or more active ingredients; and either one or both of
(a) one or more binders incorporated within the body of the pellet; and
(b) one or more coating materials on the surface of the pellet;
characterised in that either one or both of the binder and coating materials comprise one or more polymers with a Tg in the range −85 to +35° C., and, optionally, wherein the binder and/or coating material comprise a multi-phase polymer and further wherein at least one of the phases of the multi-phase polymer has a Tg in the range −85 to +35° C.
It is not necessary for the binder materials and the coating materials to have the same polymer composition.
In a further embodiment of the present invention the pellet may comprise one or more binders with a Tg in the range −85 to +35° C. incorporated within the body of the pellet and a coating material on the surface of the pellet which may comprise one or more polymers with a Tg of greater than +30° C.
The polymers used in either one or both of the binder and coating materials of the present invention are mostly amorphous. The polymers used in the invention may be soluble or insoluble in water; those which are water insoluble are preferably readily dispersible in water. The binders and coating materials of the present invention comprise polymers with a Tg in the range −85 to +35° C. and preferably a Tg in the range from −60 to +10° C. These low Tg values are characteristic of “soft” polymers, that is, they will form a film or otherwise form an adhesive bond between the detergent granules within the pellet composition under the conditions of tablet manufacture, which, applicants believe, helps to maintain the integrity of the tablet from the point of manufacture, through storage, until used by the customer.
Such binder and/or coating polymers used in the present invention may comprise polymerized residues of one or more of the following monomers: (meth)acrylic acid, (meth)acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate iso-butyl (meth)acrylate or t-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate iso-bornyl (meth)acrylate, and (meth)acrylate esters of alkylene glycols, polyalkylene glycols and (C1-C30) alkyl substituted polyalkylene glycols including esters of the formula CH2═CR1—CO—O(CH2CHR3O)m(CH2CH2CHR3O)nR2 where R1=H or methyl R2=H or C1-C30 alkyl R3=H or C1-C12 alkyl, m=0-40, n=0-40, and m+n is ≧1, such as hydroxyethyl (meth)acrylate, hydroxypropyl(meth)acrylate; C(1-30) substituted acrylamides; vinyl sulfonate, acrylamidopropanesulfonate; dimethylaminopropyl(meth)acrylamide, alkyl vinyl ethers, vinyl chloride, vinylidene chloride, N-vinylpyrollidone, allyl containing monomers; aromatic vinyl compounds such as styrene, substituted styrenes; butadiene; acrylonitrile; monomers containing acetoacetoxy functional groups such as acetoacetoxyethyl methacrylate; vinyl esters of saturated carboxylic acid, e.g., acetate, propionate, neodecanoate; acid or base containing monomers such as, for example, (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, N,N-dimethylaminoethyl methacrylate; or combinations thereof. Additionally, crosslinking and grafting monomers such as 1,4-butyleneglycol methacrylate, trimethylolpropane triacrylate, allyl methacrylate, diallyl phthalate, divinyl benzene, or combinations thereof may be used. As used herein, by “(meth)acrylate” or “(meth)acrylic”, we mean either acrylate or methacrylate for “(meth)acrylate” and acrylic or methacrylic for “(meth)acrylic”.
The polymers used in the present invention may be made using known techniques, for example, solution, emulsion or suspension polymerisation. It is preferred that they are capable of being isolated in solid form, for example by spray drying. To facilitate this, they may comprise a multiphase polymer, that is, they have at least one phase which is relatively hard compared with another phase. Alternatively, a multiphase polymer dissolved or dispersed in water may also be used.
By “multi-phase” polymer we mean polymer particles with at least one inner phase or “core” phase and at least one outer or “shell” phase. The phases of the polymers are incompatible. By “incompatible” we mean that the inner and the outer phases are distinguishable using techniques
Baxter Steven Michael
Schwartz Curtis
Gupta Yogendra N.
Johnson Stephen E.
Mruk Brian P.
Rohm and Haas Company
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