EP0163352B1

EP0163352B1 - Detergent with suds control

Info

Publication number: EP0163352B1
Application number: EP85200821A
Authority: EP
Inventors: David William York
Original assignee: Procter and Gamble European Technical Center; Procter and Gamble Co
Current assignee: Procter and Gamble European Technical Center; Procter and Gamble Co
Priority date: 1984-05-30
Filing date: 1985-05-22
Publication date: 1990-11-07
Anticipated expiration: 2005-05-22
Also published as: GB8413802D0; EP0163352A2; ATE58165T1; EP0163352A3; DE3580398D1

Abstract

Granular laundry detergents comprising conventional detersive surfactants, builders, enzymes, as well as a fabric softener clay, are coated with a mixture of silica-silicone-alkoxylated siloxane-ethoxylated alcohol which provides suds control, especially in front loading automatic washing machines.

Description

Technical field

The present invention relates to compositions suitable for use in suppressing excess suds in laundry detergent compositions containing fabric softener clay. The detergent compositions herein comprise mixtures of conventional detersive surfactants and detergency adjuvants and fabric softener clays, all in the form of granules, having coated thereon a suds control agent which comprises a mixture of particulate silica, polydimethylsiloxane, alkoxylated siloxane and ethoxylated alcohol.

Background

The use of suds suppressors of various types in laundry detergents is common commercial practice, especially in situations where the detergent is intended for use in front-loading automatic washing machines. A wide variety of suds suppressors are known from the literature, including, for example, various fatty-chain length materials adsorbed on various carrier granules, as well as various silicone materials which are well-known as suds and foam depressants.
EPO patent application 0 046 342 relates to suds control agents which comprise mixtures of alkoxylated nonionic surfactants, polydimethylsiloxane and, optionally, a particulate hydrophobic silica having preferably a particle size of 10 to 20 nm, as a foam-controller dispersed therein and siloxane- oxyalkylene copolymer as dispersing agent therefor.
Various detergent compositions which use clay as through-the-wash fabric softeners are described in several patent documents: German 29 64 114, 28 57 163, 2439541, 23 34 899 and EP-A-0 023 367, 0 026 528 and 0 028 432.
EP-A-011 340 discloses the combination or employment of a certain class of tertiary amines and smectite-type clay in or with an alkaline detergent composition, to produce textile softening benefits.
FR―A―2 524 902 discloses organic synthetic detergent compositions comprising detersive surfactants, adjuvants, bentonite and a siliconate agent, which produce textile softening benefits.
The present invention relates to granular detergent compositions which contain clay (especially smectite clay) fabric softeners, said compositions having controlled sudsing by virtue of the suds suppressor herein. Importantly, the suds suppressors described herein can be coated onto the detergent granules without undesirably affecting the fabric softening performance of the clay, nor the dispensing quality of the granules.
The present invention encompasses granular detergent compositions which comprise fabric softener clays, detersive surfactants and detersive adjuncts, all at conventional levels, said compositions being characterized in that the granules are substantially coated with a suds control agent mixture which comprises (as percentages of total composition):

i) from 0.18%-0.35% (preferably 0.25%) polydimethylsiloxane fluid;
ii) 0.06%-0.12% (preferably 0.08%) of impalpable hydrophobic silica having a particle size of 1 to 10 µm;
iii) 0.015%0.035% (preferably 0.026%) alkoxylated siloxane; and
iv) 0.5%-1.5% (preferably 0.9%) ethoxylated fatty alcohol (preferably tallow alcohol ethoxylated with 11 (avg.) EO units).

All percentages herein are by weight of the total detergent compositions, unless otherwise specified.
In a highly preferred mode, the compositions will also contain 0.1 % to 15% one or more of the amine and/or cationic fabric softener adjuncts (described in EP-A-0 026 528), together with the softener clay.

Suds control agent:

The suds control agent which is key to the practice of this invention is prepared using commercially- available materials.
i) polydimethylsiloxane fluid is commercially available in the viscosity range of 700 to 1400 mPa - s which is entirely suitable for use herein.
ii) hydrophobic silica (impalpable, 1-10 µm particle size) is also commercially available as coated "fumed" silica, or "micronized" silica from various commercial suppliers.
iii) alkoxylated siloxanes are rather thoroughly described in EP-A-0 046 342, and are, generally, ethoxylated or mixed ethoxy-propoxy polysiloxanes that are commercially available, for example, as DC 198^®.
iv) ethoxylated fatty alcohols are preferably the 8-16 ethoxylates of C₁₀-C₁₈ alcohols, and mixtures thereof such as the "tallow alcohol" ethoxylates.

In a typical process, the suds control agent is prepared by simply admixing ingredients (i)-(iv) in a suitable mixer (preferably, a mill) and blending thoroughly. The resulting composition is in fluid form that is suitable for spraying onto the detergent "base" granules.

Softener clay:

Clay softeners are well-known in the detergency patent literature and are in broad commercial use, both in Europe and in the United States. Included among such clay softeners are various heat-treated kaolins and various multi-layer smectites. Preferred clay softeners are smectite softener clays that are described in German patent document 2 334 899 and in U.K. Patent 1 400 898 which can be referred to for details. Softener clays are used in the preferred compositions at levels of at least 1%, generally 1-20%, preferably 2-7%. Highly preferred smectite clay softeners are those having an exchange capacity of at least 50 meq/100 g (measured as Ca⁺⁺ exchange; expressed as CaC0₃ capacity).

Detersive surfactants:

The detergent compositions of this invention will contain organic surface-active agents ("surfactants") to provide the usual cleaning benefits associated with the use of such materials.
Detersive surfactants useful herein include well-known synthetic anionic, amphoteric and zwitterionic surfactants. Typical of these are the alkyl benzene sulfonates, alkyl- and alkylether sulfates, paraffin sulfonates, olefin sulfonates, amine oxides, a-sulfonates of fatty acids and of fatty acid esters, and the like, which are well-known from the detergency art. In general, such detersive surfactants contain an alkyl group in the Cg-C_le range; the anionic detersive surfactants can be used in the form of their sodium, potassium or triethanolammonium salts. U.S. Patent 4111 855 contains detailed listings of such typical detersive surfactants. C₁₁―C₁₆ alkyl benzene sulfonates, C,₂-C_l, paraffin-sulfonates and alkyl sulfates are especially preferred in the compositions of the present type.
Also useful herein as the surfactant are the water-soluble soaps, e.g. the common sodium and potassium coconut or tallow soaps well-known in the art.
The surfactant component can comprise as little as 1% of the laundry detergent compositions herein, but generally the compositions will contain 5% to 40%, preferably 6% to 30%, of surfactant. Mixtures of the anionics, such as the alkyl benzene sulfonates, alkyl sulfates and paraffin sulfonates are preferred for through-the-wash cleansing of a broad spectrum of soils and stains from fabric.

Detersive adjuncts

The compositions herein can contain other ingredients which aid in their cleaning performance. For example, it is highly preferred that through-the-wash detergent compositions contain a detergent builder and/or metal ion sequestrant. Compounds classifiable and well-known in the art as detergent builders include the nitrilotriacetates, polycarboxylates, citrates, water-soluble phosphates such as tripolyphosphate and sodium ortho- and pyro-phosphates, silicates, and mixtures thereof. Metal ion sequenstrants include all of the above, plus materials like ethylenediaminetetraacetate, the amino- polyphosphonates and phosphates (Dequest@) and a wide variety of other poly-functional organic acids and salts too numerous to mention in detail here. See U.S. Patent 3 579 454 for typical examples of the use of such materials in various cleaning compositions. In general, the builder/sequestrant will comprise about 0.5% to 45% of the composition. The 1-10 pm size zeolite (e.g. zeolite A) builders disclosed in German patent 2 422 655 are especially preferred for use in low-phosphate compositions which contain the softeners described herein.
The laundry compositions herein also preferably contain enzymes to enhance their through-the-wash cleaning performance on a variety of soils and stains. Amylase and protease enzymes suitable for use in detergents are well-known in the art and in commercially available liquid and granular detergents. Commercial detersive enzymes (preferably a mixture of amylase and protease) are typically used at levels of 0.001% to 2%, and higher, in the present compositions.
Moreover, the compositions herein can contain, in addition to ingredients already mentioned, various other optional ingredients typically used in commercial products to provide aesthetic or additional product performance benefits. Typical of such ingredients (used at 0.5-35% levels) are: pH regulants, perfumes, dyes, bleaches, optical brighteners, soil suspending agents, hydrotropes and gel-control agents, freeze- thaw stabilizers, bactericides, preservatives, bleach activators and the like.
Another class of optional ingredient includes the softener adjuncts known in the patent literature for use in combination with smectite clay softeners. In general such materials are amine or quaternary ammonium compounds, and mixtures thereof. Included among such preferred materials are the C₁₂―C₁₈ alkyl trimethyl ammonium chlorides and bromides, dioctyl dimethyl ammonium chloride and bromide, coconutalkyl amine, dicoconut alkyl amine, tri-C,₂-C₁₄ alkyl amine, and the like.
In a through-the-wash mode, the compositions prepared in the manner of this invention are typically used at a concentration of at least 500 ppm, preferably 0.10% to 1.5%, in an aqueous laundry bath at pH 7-11 to launder fabrics. The laundering can be carried out over the range from 5°C to the boil, with excellent results and without excessive sudsing.

Industrial application

The compositions herein are prepared by separately forming the suds control agent and the detergent "base" granule, and then coating the granule with the suds control agent. In a commercial process, the coating will not usually completely cover each granule, and, indeed, perfect coating is not necessary to the successful practice of the invention; "substantially" coating the base granules will suffice.
The base granules can be formed from an aqueous crutcher mix by any of a number of well-known processes, but conventional spray-drying is convenient.
The coating can be applied in any number of ways, but simple spraying onto the granules is convenient.
One of the advantages of the present invention is that it can be performed using conventional procedures and apparatus known in the detergency arts.
The following examples are typical of a composition prepared according to this invention, but are not intended to be limiting thereof.

Example I

An aqueous crutcher mix comprising the following ingredients is prepared (percentages listed relate to percent ingredients in the complete formulation after spray-drying) and spray-dried in a standard tower to form base granules.

^*Natural smectite; ion-exchange capacity above 50 meq/100 g clay
^**U.S. Patent 3.927.967.
^***Dry-mixed with granule after spray-drying.

A suds-control agent is prepared by milling 0.09% hydrophobic silica (1-10 um); 0.3% polydimethylsiloxane fluid; 1.0% tallow alcohol ethoxylate (11) and 0.015% ethoxy/propoxy siloxane (all percentages reported based on final composition) and sprayed onto the base granules.
The composition of Example I is free-flowing and exhibits excellent through-the-wash fabric softening performance.

Example II

A highly preferred spray-dried granule which contains a mixed softener active comprising clay/amine/ quaternary is prepared as follows.

^*The indicated ingredients are mixed with the granules after spray-drying.

A suds control agent comprising microfine hydrophobic silica (0.08%; Sipernat D-10^®) plus tallow alcohol ethoxylate (E011) 0.9% plus ethoxypropoxysiloxane (0.026%; DC 198^@) and polydimethylsiloxane (0.25%; DC 200⁰) is prepared by milling the ingredients together. The agent is then sprayed uniformly onto the granules of Example II.

Claims

1. A granular detergent composition comprising conventional detersive surfactants, fabric softener clay, and detersive adjuncts, characterized in that the granules of said composition are substantially coated with a suds control agent comprising (as percentages of total composition):

i) 0.18-0.35% polydimethylsiloxane fluid;

ii) 0.06-0.12% impalpable hydrophobic silica having a particle size of 1-10 µm;

iii) 0.015-0.035% alkoxylated siloxane; and

iv) 0.5-1.5% ethoxylated alcohol.

2. A granular detergent composition according to Claim 1 which comprises 0.5%-45% sodium tripolyphosphate, nitrilotriacetate, zeolite, or mixtures thereof as a detersive adjunct.

3. A granular detergent composition according to Claim 2 which comprises smectite clay as the fabric softener clay.

4. A granular detergent composition according to Claim 3 which additionally comprises 0.1 %-15% of an amine or quaternary ammonium fabric softener adjunct, or mixtures thereof.

5. A granular detergent composition according to Claims 1-4 which contains a bleach, a bleach activator or an enzyme as a detersive adjunct.