Pasty washing agent

Details Pasty washing agent Pasty washing agent

2001-06-08

2003-09-30

Gupta, Yogendra N. (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

For cleaning a specific substrate or removing a specific...

C510S309000

Reexamination Certificate

active

06627592

ABSTRACT:

This invention relates to paste-form detergents for use in institutional laundries, to a process for their production and to a disinfecting washing process for institutional laundries.
Detergents used in the home are adapted to domestic requirements. Thus, they are normally powders or are sufficiently liquid to lend themselves to problem-free pouring and dosing. Since liquid detergents are also expected to be stable in storage over relatively broad temperature ranges, organic solvents and/or hydrotropes are often added to them although they do not themselves make any contribution to the washing/cleaning result and, for this reason, are not wanted. One way of avoiding possible dosing problems with insufficiently liquid detergents is proposed in European patent application EP 253 151 A2. This document describes liquid and, in some cases, highly viscous detergents based on nonionic and anionic surfactants which contain polyethylene glycol as hydrotrope and which do not have to be dosed in liquid form by the user, but instead are packed in portions in bags of water-soluble material, for example polyvinyl alcohol.
The paste-form detergent described in European patent EP 295 525 B1 consists of a liquid phase of nonionic surfactant which is liquid at temperatures below 10° C. and —dispersed therein—a solid phase with a certain particle size consisting of washing alkalis, sequestering agents and optionally anionic surfactants. The surfactants or surfactant mixtures used must have a pour point (solidification point) below 5° C. to avoid solidification of the paste at low transportation and storage temperatures. This detergent paste is intended for institutional laundries and has such good flow properties that it can be pumped through a suction line by a conventional delivery pump. However, it has been found that pastes of the type in question are not always able satisfactorily to guarantee the homogeneity of their ingredients during the production process and often tend to separate, even in storage. This separation involves not only the separation of solid from liquid ingredients, but also phase separation of the liquid ingredients.
Another paste-form detergent which contains as nonionic surfactant from 40 to 70% by weight of ethoxylated C
10-20
fatty alcohol—liquid at room temperature—with an average degree of ethoxylation of 1 to 8, 20 to 50% by weight of ethoxylated and propoxylated C
10-20
fatty alcohols—liquid at room temperature—with an average degree of ethoxylation of 2 to 8 and an average degree of propoxylation of 1 to 6 and 1 to 10% by weight of soap is described in International patent application WO 95/09229. This paste-form detergent is so pseudoplastic that it does not flow under the effect of gravity at room temperature, but assumes a distinctly lower viscosity on shearing and then flows under the effect of gravity. This paste-form detergent is preferably dosed by shearing to reduce its viscosity and then dosing the flowable product using feed pumps.
International patent application WO 98/10049 describes a paste-form detergent for use in institutional laundries containing nonionic surfactant, organic and/or inorganic builder, alkalizing agent and optionally bleaching agent, enzyme, redeposition-inhibiting polymer and/or other typical ingredients, characterized in that it contains 5% by weight to 30% by weight of an ethoxylated alcohol corresponding to the general formula R
1
—(OC
2
H
4
)
m
—OH (I), in which R
1
is an alkyl or alkenyl group containing 9 to 15 carbon atoms and the average degree of ethoxylation m can assume values of 1 to 8, 1% by weight to 20% by weight of an ethoxylated alcohol corresponding to the general formula R
2
—(OC
2
H
4
)
n
OH (II), in which R
2
is an alkyl or alkenyl group containing 12 to 22 carbon atoms and the average degree of ethoxylation n can assume values of 3 to 14, with the proviso that n is greater than m by at least 1.0, 20% by weight to 80% by weight of alkalizing agent, more particularly alkali metasilicate, 1% by weight to 20% by weight of medium-chain to long-chain alcohol or alkyl ether corresponding to the general formula R
3
—O—R
4
(III), in which R
3
is an alkyl or alkenyl group containing 6 to 22 carbon atoms and, more particularly, 8 to 22 carbon atoms and R
4
is hydrogen or an alkyl group containing 1 to 6 carbon atoms, and up to 15% by weight of organic builder of the polymeric polycarboxylate type. Polymeric polycarboxylates in this context are understood to be polymerization products of unsaturated mono- and/or dicarboxylic acids which, apart from carboxyl groups, have no other functionalities.
Institutional washing processes differ from household washing inter alia in the fact that, although different types of fabrics and variously soiled fabrics also accumulate, the material simultaneously arriving for washing contains largely the same bulk laundry which allows a washing technique specially adapted to the particular cleaning problem. However, there is a greater demand for high-performance cleaning processes in institutional laundries than in domestic washing because heavily soiled washing and infected hospital laundry can accumulate. To keep detergent consumption as low as possible, institutional laundries almost exclusively use water freed from hardness ions for washing. A detailed overview can be found in the article by H. Krü&bgr;mann and H. G. Hloch entitled “Waschverfahren in der gewerblichen Wäscherei”, Tenside Surfactants Detergents 24 (1987), 341-349 and the literature cited therein.
The detergents known from the documents cited above have high cleaning performance and are particularly suitable for the institutional washing of soiled laundry. However, in cases where laundry contaminated with microorganisms, possibly even pathogenic microorganisms, accumulates, they are unable to meet the need for simultaneous disinfection so that disinfecting preparations have to be used with them.
Accordingly, there was a need for a detergent of simple composition which would combine high cleaning performance with a disinfecting effect when used in the wash cycle of conventional institutional washing machines.
The present invention, which is intended to satisfy that need, relates to a paste-form detergent for use in institutional laundries containing nonionic surfactant, organic and/or inorganic builder, peroxygen-based bleaching agent and optionally other typical ingredients, characterized in that it contains 30% by weight to 60% by weight of nonionic surfactant, 0.5% by weight to 5% by weight and more particularly 0.5% by weight to 3% by weight of fatty acid and/or fatty acid alkali metal salt, 5% by weight to 15% by weight of citrate and/or citric acid and 15% by weight to 35% by weight of inorganic peroxygen compound and is free from alkali metasilicate and bleach activator. It must be regarded as surprising that, despite the absence of bleach activators, i.e. precursor compounds forming percarboxylic acids under perhydrolysis conditions, such as esters and amides, a detergent with a disinfecting effect is obtained.
The present invention also relates to a process for the washing and disinfection of laundry in institutional laundries using a corresponding paste-form detergent. The detergent is preferably used in the 60° C. wash program, i.e. at a washing temperature of about 60° C. In one preferred embodiment of the process according to the invention, not all the ingredients of the paste-form detergent according to the invention need be used together in one detergent paste, instead one or more of the ingredients, particularly the inorganic peroxygen compound, can be separately used, in which case a paste-form detergent corresponding to a detergent according to the invention except for the missing ingredient(s) is additionally used. In this particular embodiment, it is possible where a multiple-chamber washing installation is used to introduce the ingredient used separately, particularly the inorganic peroxygen compound, into the same chamber as or into a different chamber from the paste-form detergent. The word “

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