Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
1998-08-27
2001-03-27
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S359000, C510S495000, C510S509000, C510S510000, C264S117000, C264S140000
Reexamination Certificate
active
06207635
ABSTRACT:
TECHNICAL FIELD
The invention involves a process for making built high active detergent agglomerates having improved free flow properties.
BACKGROUND OF THE INVENTION
Laundry detergent granules comprise one or more surfactants (usually of the anionic type) and one or more detergency builders (typically phosphates, carbonates, zeolites, etc.) Detergent granules are typically made by preparing a paste of the detergent ingredients, and spray drying the paste to form granules. Such products also can be made by agglomerating a mixture of the surfactant and builder in a mixer. In an agglomeration process, the anionic surfactant in its neutralized form can be used or it can be introduced into the agglomeration process in its acid form and be neutralized in situ by alkaline materials (e.g. sodium carbonate). Optional detergent materials such as brighteners, soil release agents, etc. can be agglomerated along with the surfactant and builder or can be mixed with the agglomerates after they are formed. Generally, agglomeration provides the ability to produce higher density detergent products than those which are produced by spray drying.
A frequent problem with detergent agglomerates, particularly those having a surfactant level of 20% or more, is a tendency to be somewhat sticky (i.e., poor free flow). To help alleviate this problem, flow aids such as clay, talc, zeolites or silica are typically used.
Representative examples of prior patents relating to agglomeration processes for the production of detergent granules are: U.S. Pat. No. 5,133,924 (Appel); U.S. Pat. No. 5,164,108 (Appel); U.S. Pat. No. 5,160,657 (Bartolloti); Brit. Pat. 1,517,713 Unilever); Euro. Appln. 451,894 (Curtis); U.S. Pat. No. 5,108,646 (Beerse et al.); Euro. Pat. Appln. 351,937 (Hollingsworth et al ); and U.S. Pat. No. 5,205,958.
The object of the present invention is to provide a process for producing detergent agglomerates having high surfactant levels and improved free flow characteristics.
SUMMARY OF THE INVENTION
The present invention is directed to a process comprising the steps of:
(a) preparing a mixture of detergent components in a mixer, the said components comprising:
(1) from about 20% to about 35% of a compound selected from the group consisting of anionic surfactants and acid precursors of anionic surfactants;
(2) from about 0% to about 65% particulate phosphate builder selected from the group consisting of polyphosphate, pyrophosphate, and mixtures thereof;
(3) from about 6% to about 60% of a particulate carbonate selected from the group consisting of sodium carbonate, potassium carbonate, and mixtures thereof; wherein when an acid precursor of an anionic surfactant is used in (a)(1), the amount of carbonate is at least 2 times that which is sufficient to neutralize the said acid precursor;
wherein at least about 20% of the total amount of Components (2) and (3) meets a particle size specification of 97% particles less than 50 microns and a median particle size of 5 to 20 microns, and
(b) agglomerating the mixture from Step (a) in a second mixer to produce detergent agglomerates.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, it has been found that in the preparation of anionic detergent agglomerates having high anionic surfactant content, (i.e., 20% or above) and containing carbonate and, optionally, phosphate builders, improved free flow characteristics can be achieved if at least 20% of the total (i.e., combined) amount of particulate carbonate/phosphate used in preparing the agglomerates meets a specification of 97% particles less than 50 microns and a median particle size of 5 to 20 microns.
Raw Materials
Anionic surfactant is an essential component of compositions prepared by the present process. Such surfactants are well known in the art. The anionic surfactants useful in the subject invention are preferably the alkali metal (i.e., sodium and potassium) salts of alkylbenzene sulfonates or alkyl sulfates or mixtures thereof. Examples of other anionic surfactants which are also useful are the alkali metal salts of paraffin sulfonates, alkyl glyceryl ether sulfonates and alkyl ether sulfates, all having about 8 to about 18 carbon atoms in their alkyl chains. The anionic surfactant raw materials preferably have a moisture content of less than about 1.0%, more preferably less than about 0.5%. Based on the total weight of raw materials added during the process of the subject invention, the amount of anionic surfactant is from about 20% to about 35%, preferably from about 20% to about 30%.
Preferred alkylbenzene sulfonates useful in the subject process include those with an alkyl portion which is straight chain or branched chain, preferably having from about 8 to about 18 carbon atoms, more preferably from about 10 to about 16 carbon atoms. The alkyl chains of the alkylbenzene sulfonate preferably have an average chain length of from about 11 to about 14 carbon atoms. Alkylbenzene sulfonate which includes branched chain alkyl is termed ABS. Alkylbenzene sulfonate which is all straight chain is preferred because it is more easily biodegraded; it is termed LAS.
Preferred alkyl sulfates useful in the subject process include those with an alkyl portion which is straight chain or branched chain, preferably having from about 8 to about 24 carbon atoms, more preferably from about 10 to about 20 carbon atoms, more preferably still from about 12 to about 18 carbon atoms. The alkyl chains of the alkyl sulfates preferably have an average chain length of from about 14 to about 16 carbon atoms. The alkyl chains are preferably linear. Alkyl sulfates are typically obtained by sulfating fatty alcohols produced by reducing the glycerides of fats and/or oils from natural sources, especially from tallow or coconut oil.
Preferred anionic surfactants useful in the subject invention process may also be combinations of alkylbenzene sulfonates and alkyl sulfates, whether mixed together or added during the process separately. Combinations having a ratio of alkylbenzene sulfonate to alkyl sulfate of from about 20:80 to about 80:20 are preferred;. those having a ratio of from about 40:60 to about 60:40 are more preferred. Additional disclosure of anionic synthetic surfactants can be found in U.S. Pat. No. 3,664,961, Norris, issued May 23, 1972, incorporated by reference herein. In practicing the process herein the anionic surfactant can be introduced in its neutralized (i.e., alkali metal) form or it can be introduced in its unneutralized acid precursor form, in which case it is neutralized by excess alkali metal carbonate, as discussed later herein.
Optionally, phosphates are used as builders in compositions made according to the process herein. The phosphate builder raw materials useful in the subject invention process are in particulate form and consist essentially of the water-soluble salts (e.g., the sodium and potassium salts) of polyphosphates (e.g., tripolyphosphate, hexametaphosphate, etc.) or pyrophosphates or mixtures thereof. The phosphate builder raw materials preferably have a moisture content of less than about 2%, more preferably less than about 1%. Based on the total weight of raw materials added during the process of the subject invention, the amount of phosphate builder is typically from about 5% to about 65%, preferably from about 15% to about 55%, more preferably from about 25% to about 45%. Phosphate builder raw materials are typically supplied from their manufacturers in powder form, usually having a median particle size of from about 25 microns to about 50 microns. Carbonate raw materials are typically supplied from their manufacturers in granular form, usually having a particle size of from about 25 microns to about 150 microns. “As is” median particle size for polyphosphate and carbonate varies for supplies obtained in different geographies as well as by supplier. For use in the present invention the polyphosphate builder and/or carbonate are ground to a particle size such that at least about 20% preferably at least about 40% of the total amount of particles of phos
Adams Donald Scott
Kao Junan
Riddick Eric Fitzgerald
Yeazell Bruce Albert
Bolam Brian M.
Douyon Lorna M.
Miller Steven W.
The Procter & Gamble & Company
William Zerby Kim
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