Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2001-04-18
2003-07-22
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S441000, C510S504000, C510S507000, C510S509000, C023S3130FB
Reexamination Certificate
active
06596684
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a granular detergent component suitable for incorporation into particulate laundry detergent compositions, and a novel process for its preparation. The granular detergent component contains a cationic, zwitterionic or amphoteric surfactant.
BACKGROUND
Cationic, amphoteric and zwitterionic surfactants are useful ingredients in laundry detergent compositions, generally used in relatively minor amounts as co-surfactants to supplement non-soap anionic surfactants and, in some cases, nonionic surfactants.
These materials are commercially available as aqueous solutions of relatively low concentration, generally below 50 wt %, for example, 30 to 40 wt %. For some materials, for example, water-soluble quaternary ammonium cationic surfactants having a single long hydrocarbon chain, mobile solutions of higher concentration are not possible because gelling occurs.
While these solutions may be suitable for inclusion in liquid detergent compositions, or for incorporation in detergent powders via traditional slurry-making and spray-drying processes, the large amount of associated water can pose problems in preparing granular detergent compositions or components by non-spray-drying (mixing and granulation) processes. For incorporation into “compact” or “concentrated” laundry powders, a granule containing a relatively high surfactant loading is required.
PRIOR ART
WO 96 17042A (Procter & Gamble) discloses detergent granules containing a water-soluble cationic surfactant and an inorganic carrier, the granules also containing an anionic surfactant in a weight ratio to the cationic surfactant of less than 1:1, and preferably less than 0.5:1. The inorganic carrier material is zeolite. The granules are prepared by evaporating and concentrating a solution of the cationic and anionic surfactants to a concentration above 50 wt %, and then granulating with the carrier material. The presence of the anionic surfactant prevents gelling during the concentration step.
WO 98/53037A (Procter & Gamble) discloses a process for the preparation of cationic surfactant granules, in which a aqueous solution or dispersion of cationic surfactant, optionally plus sodium silicate and/or filler, is dried in the presence of a drying gas, preferably air, at a temperature of less than 250° C. The preferred drying method is co-current spray-drying.
The present inventors have now discovered that granules containing more than 20 wt % of cationic, amphoteric or zwitterionic surfactant may be obtained in a non-spray-drying process, without the need for elevated temperatures and without the need for anionic surfactant.
DEFINITION OF THE INVENTION
The invention accordingly provides a process for the preparation of a granular detergent component comprising
(a) at least 20 wt % of a surfactant selected from cationic surfactants, zwitterionic surfactants, amphoteric surfactants and mixtures thereof,
(b) an inorganic carrier material,
which process comprises spraying an aqueous solution of the surfactant (a) onto moving granules of the inorganic carrier material (b) in the presence of a drying gas at a temperature within the range of from 65 to 200° C., preferably from 80 to 200° C., and more preferably from 100 to 150° C.
In a second aspect, the present invention provides a granular detergent component comprising
(a) at least 20 wt % of a surfactant selected from cationic surfactants, zwitterionic surfactants, amphoteric surfactants and mixtures thereof,
(b) an inorganic carrier material,
the granular detergent component being free of sodium sulphate.
In a third aspect, the present invention provides a particulate laundry detergent composition comprising in total from 5 to 60 wt % of one or more organic detergent surfactants, from 10 to 80 wt % of one or more detergency builders and optionally other detergent ingredients, which composition includes a granular detergent component as defined above.
DETAILED DESCRIPTION OF THE INVENTION
The Cationic, Amphoteric or Zwitterionic Surfactant
The invention is applicable to any cationic, amphoteric or zwitterionic surfactant which is supplied as a relatively dilute (for example, less than 50 wt %) aqueous solution. It is especially applicable to such surfactants which are sensitive to heat and liable to degradation or decomposition at temperatures above 200° C., or even above 150° C.
Preferred water-soluble cationic surfactants are quaternary ammonium salts of the general formula I
R
1
R
2
R
3
R
4
N
+
X
−
(I)
wherein R
1
is a relatively long (C
8
-C
18
) hydrocarbon chain, typically an alkyl, hydroxyalkyl or ethoxylated alkyl group, optionally interrupted with a heteroatom or an ester or amide group; each of R
2
, R
3
and R
4
(which may be the same or different) is a short-chain (C
1
-C
3
) alkyl or substituted alkyl group; and X is a solubilising anion, for example a chloride, bromide or methosulphate ion.
In a preferred class of compounds, R
1
is a C
8
-C
18
alkyl group, more preferably a C
8
-C
10
or C
12
-C
14
alkyl group, R
2
is a methyl group, and R
3
and R
4
, which may be the same or different, are methyl or hydroxyethyl groups.
In an especially preferred compound, R
1
is a C
12
-C
14
alkyl group, R
2
and R
3
are methyl groups, R
4
is a 2-hydroxyethyl group, and X
−
is a chloride ion. This material is available commercially as Praepagen (Trade Mark) HY from Clariant GmbH, in the form of a 40 wt % aqueous solution.
Other classes of cationic surfactant include cationic esters (for example, choline esters).
Preferred zwitterionic surfactants include betaines of the formula II
wherein R
5
is a hydrocarbon chain containing 8 to 20 carbon atoms, optionally interrupted by an amide group, and m is an integer from 1 to 4.
Especially preferred zwitterionic surfactants are betaines of the formula IIa
wherein R
6
is a C
8
-C
18
alkyl group, and n is an integer of from 2 to 4.
An especially preferred material is cocoamidopropyl betaine (CAPB), in which R
6
is C
12
-C
14
alkyl and m is 3.
Preferred amphoteric surfactants include alkyl amine oxides of the general formula III
R
7
R
8
R
9
N→O (III)
wherein R
7
is typically a C
8
-C
18
alkyl group, for example, C
12
-C
14
alkyl, and R
8
and R
9
, which may be the same or different, are C
1
-C
3
alkyl or hydroxyalkyl groups, for example, methyl groups. The most preferred amine oxide is coco dimethylamine oxide, in which R
7
is C
12
-C
14
alkyl and R
8
and R
9
are methyl groups.
The Inorganic Carrier Material
The granular detergent component of the invention contains, as an essential ingredient, an inorganic carrier material.
According to a first preferred embodiment of the invention, the inorganic carrier material consists to an extent of at least 80 wt % of water-soluble material. The use of a predominantly water soluble carrier material is believed to be particularly advantageous in products intended for laundering by hand.
Preferred water-soluble carrier materials are sodium carbonate, sodium tripolyphosphate and mixtures thereof. Sodium carbonate is especially preferred.
In this embodiment of the invention, up to 20 wt % of the inorganic carrier material may be constituted by water-insoluble material. Preferred water-insoluble carrier materials are aluminosilicates, particularly crystalline alkali metal aluminosilicates (zeolites), silicas, calcites and clays.
Thus, advantageously the inorganic carrier material comprises from 80 to 100 wt % of sodium carbonate, and optionally up to 20 wt % of water-insoluble carrier material selected from crystalline alkali metal aluminosilicates (zeolites), silicas, calcites and clays.
In a second preferred embodiment of the invention, the inorganic carrier consists at least partially of water-insoluble material. Preferably the inorganic carrier material comprises from 80 to 100 wt % of water insoluble material. Advantageously, the inorganic carrier material may comprise from 20 to 100 wt % of crystalline alkali metal aluminosilicate. Most preferably, the inorganic carrier material comprise
Astley Martin Peter
Emery William Derek
Douyon Lorna M.
Rimma Mitelman
Unilever Home & Personal Care USA divison of Conopco, Inc.
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