By a News Reporter-Staff News Editor at Life Science Weekly — From Washington, D.C., NewsRx journalists report that a patent application by the inventors LETZELTER, Nathalie Sophie (Trimdon, GB); CURCIC, Nikola (Newcastle upon Tyne, GB); ALDA, Elena (Newcastle upon Tyne, GB); PRESTON, Karen Margaret (Newcastle upon Tyne, GB); KEULEERS, Robby Renilde Francois (Lippelo (Sint-Amands); BE), filed on December 12, 2013, was made available online on July 3, 2014 (see also The Procter & Gamble Company).
The patent’s assignee is The Procter & Gamble Company.
News editors obtained the following quote from the background information supplied by the inventors: “The detergent formulator is constantly facing cleaning and stability issues. Unit dose products can be more challenging than loose powders or liquids. Detergents in unit dose form have associated constrains in terms of volume that imply limitations in terms of the amount of actives.
“Most if not all the cleaning ingredients can be susceptible to degradation to a greater or lesser extent. In unit dose products the different ingredients are in close proximity to one another this can negatively affect the stability of the product. The current trend is to reduce the size of the unit dose product making the cleaning and stability issues more of a challenge.
“In recent years cleaning and stability of cleaning products have been impacted by the tendency to eliminate phosphate from cleaning formulations. Phosphate is not only an excellent cleaning active but also contributes to product stability by adsorbing moisture from the surrounding environment and/or from the product itself.
“Another added complication that the detergent formulator faces is that different actives can be in different physical forms, some of them are in liquid form and some other in solid form. In order to have a cleaning composition in one physical form processing of ingredients in a different form is required. For example, organic dispersants such as organic polymers and organic builders are usually synthesized in liquid form. A great deal of work and high cost is associated with the transformation of these materials into particles in order to introduce them into products in solid form.
“For example, a great deal of work has been done to convert organic polymers into particles. US 2012/0225450 A1 relates to carboxyl-containing polymer in solid form. These polymers are usually synthesized in aqueous solution. WO2011/133483 relates to a particle comprising an organic builder, in particular an aminocarboxylate builder. Aminocarboxylate builders are usually synthesized in aqueous solution.
“The usual form in which aminocarboxylate and other dispersants, for example salts of glutamic acid N,N-diacetic acid (GLDA), methyl glycine diacyl acid (MGDA) are available is as liquid solutions with different active content. After drying the solution, the powder or granules, especially when obtained in the amorphous state, usually show hygroscopic and deliquescent properties which make them difficult to use in detergents. Moreover, the granules obtained from a granulation process (such as fluid bed granulation) are somewhat brittle and thus cannot grow easily to the required size, resulting in slow processing and lots of fines. In addition, whether in powder or granule form, the material can exhibit hygroscopic and deliquescent properties, and this will render the material sticky and thus introduce storage, handling, and manufacturing problems. These problems can be more acute in the case of dispersants such as aminocarboxylic acids and organic polymers. WO2011/076769 A1 addresses the problem by providing a process to make coated GLDA particles.
“Flow properties of particles are critical in many ways. During manufacture of the particles themselves, they must flow smoothly relative to one another, e.g. in a fluid bed. Additionally, they must then be successfully transported to storage and transport containers. Finally, they must again be transported from storage and fed into a powder or tablet manufacturing facility. Flow problems arise due to several causes. For dispersants, poor flow can be due to theirs hygroscopic properties.
“Another problem associated with unit-dose products, in particular with water-soluble packs comprising a cleaning composition and an enveloping material is the interaction between the cleaning composition and the enveloping material. The enveloping material is water-soluble and usually contains a certain amount of water thus the presence of water in the cleaning composition could affect the integrity and properties of the film.
“A further problem associated with multi-compartment unit dose products, is that the enveloping material is usually moisture permeable, allowing the transfer of moisture across compartments, negatively impacting on the stability of the product.
“The objective of this invention is to provide a product that has a good environmental and cleaning profile, it is stable upon storage and it is favourable from a process viewpoint.”
As a supplement to the background information on this patent application, NewsRx correspondents also obtained the inventors’ summary information for this patent application: “According to a first aspect of the invention there is provided a multi-compartment water-soluble pack. The pack comprises a cleaning composition, preferably an automatic dishwashing detergent composition and an enveloping material. The enveloping material is preferably a water-soluble film. Both the cleaning composition and the enveloping material are water-soluble. They readily dissolve when exposed to water in an automatic dishwashing process, preferably during the main wash.
“The pack has at least two compartments. The first compartment contains a first composition in liquid form. Herein sometimes referred to as ‘first liquid’. The first liquid comprises a hygroscopic material, preferably solubilised therein. The first liquid also comprises a high level of water. The water is partially or totally immobilized by the hygroscopic material providing great chemical stability to the cleaning composition and mechanical stability to the enveloping material.
“The first liquid has a low equilibrium relative humidity (eRH) (less than about 65%, preferably less than about 60%, more preferably less than about 50% and especially less than about 40% as measured at 20.degree. C.) and thereby low water activity that contributes to the stability of the pack. The eRH is measured as specified in the method detailed herein below.
“In a preferred embodiment the product comprises a second compartment containing a second composition. The second composition comprises a moisture sensitive ingredient. Usually the first and second compositions contain different levels of water, however, due to the water retention capacity of the first liquid the water difference does not seem to affect the moisture sensitive ingredient. An ingredient forming part of a cleaning composition is considered to be moisture-sensitive when it can be partially or fully degraded during storage by the interaction of moisture with the composition thereby decreasing the detergency activity of the ingredient as for example detergency bleach, enzymes, etc. The activity (i.e., cleaning capacity) of moisture sensitive ingredients can decrease during storage when the cleaning composition is exposed to moisture. The second composition can be in any physical form, for example, it can be a liquid, gel or paste or be a solid composition. Preferably the second composition is in solid form, this allows having a product with different actives in their native forms thereby simplifying the manufacture of the product.
“In a preferred embodiment the compartments are in a superposed configuration, i.e., one above the other, thereby providing improved stability by reducing the area of the compartments directly exposed to the surrounding environment.
“In a preferred embodiment the hygroscopic material is deliquescent. A ‘deliquescent’ material is so good at water absorption that when it is left in dry form at ambient conditions it takes so much moisture that it dissolves and becomes liquid. Deliquescent materials provide benefits in terms of water binding thereby contributing to the stability of the pack.
“Preferably the hygroscopic material is an organic material. Preferably the hygroscopic material is a dispersant, more preferably a salt of a carboxylic acid. Preferred carboxylic acid salts for use herein include organic polymers containing carboxylate monomers, carboxylates such as citrate, aminocarboxylates such as salts of MGDA, GLDA, etc. The hygroscopic material not only contributes to the stability of the pack but it is also an active ingredient in the cleaning process. Preferably, the first composition comprises from 10 to 60%, more preferably from 20 to 60% and especially from 30 to 60% by weight of hygroscopic material.
“For environmental reasons the pack is preferably free of phosphate, i.e. the composition comprises less than 20, more preferably less than 10 especially less than 5 ppm by weight of the composition of phosphate.
“In preferred embodiments the first composition has an ionic strength of at least about 15 moles/1, preferably 20 moles/1 and especially 30 moles/l at 20.degree. C. During the course of this work, it has been found that higher ionic strength of the first liquid is associated with lower eRH.
“Preferably the first liquid is a Newtonian fluid, this helps in terms of manufacture of the pack and in terms of solubility of the composition in the cleaning process. Alternatively, the first liquid can be shear thinning.
“According to a second aspect of the invention there is provided a process for making a multi-compartment water-soluble pack comprising the step of forming and filing a first open compartment with a first liquid composition comprising a hygroscopic material in liquid form. This process is advantageous because it allows the use of hygroscopic materials in the form in which they are synthesized, avoiding the need of secondary process steps to convert the liquid hygroscopic material into a solid. This would involve not only drying the material but also secondary steps to convert the dried material into particles.
BRIEF DESCRIPTION OF THE DRAWINGS
“FIG. 1 is a plot of the percent amylase enzyme retained versus initial after storage for 4 weeks at 32 C and 80% relative humidity.
“FIG. 2 is a plot of the percent protease enzyme retained versus initial after storage for 4 weeks at 32 C and 80% relative humidity.”
For additional information on this patent application, see: LETZELTER, Nathalie Sophie; CURCIC, Nikola; ALDA, Elena; PRESTON, Karen Margaret; KEULEERS, Robby Renilde Francois;. Cleaning Pack. Filed December 12, 2013 and posted July 3, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=2452&p=50&f=G&l=50&d=PG01&S1=20140626.PD.&OS=PD/20140626&RS=PD/20140626
Keywords for this news article include: Anions, Detergents, Phosphates, Phosphoric Acids, Surface-Active Agents, The Procter & Gamble Company.
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