PT88598B - PROCESS FOR THE PREPARATION OF A DETERGENT AQUOSA LIQUID THIXOTROPIC FOR AUTOMATIC LAUNDERING OF CRAZY CONTAINING AN ANTI-FORMACATIVE AGENT OF FILM BASED ON SILICA - Google Patents

Abstract

Thixotropic aqueous liquid automatic dishwashing detergent composition with improved anti-filming properties and method of using the detergent composition. The detergent composition comprises alumina or titanium dioxide anti-filming agent, inorganic builder salts, chlorine bleach, bleach-stable detergent and a thixotropic thickener. The compositions provide reduced filming on dishware, glassware, china and the like, praticularly in hard water, and remain stable against phase separation.

Description

FIELD OF THE INVENTION

The present invention relates to a process for the preparation of a thixotropic aqueous liquid detergent composition for automatic dishwashing with better anti-film properties and a method for using the detergent composition for washing dishes, glasses, porcelain articles. and others.

The dishwashing composition contains silica, as a film-forming agent, inorganic structuring salts, chlorine-based bleaching agent, stable detergent in the presence of the bleaching agent and a thixotropic thickener.

The dishwashing detergent composition of the present invention reduces the formation of films on plates, glasses, porcelain and the like, especially in hard water, and remains stable against phase separation.

More specifically, the invention relates to the use of silica as an anti-film forming agent in thixotropic aqueous liquid detergent compositions for dishwashing, to reduce film formation.

Detergent compositions do not require the addition of a rinse aid, are stable in storage, do not settle and are quickly redispersible and spillable.

the present invention also relates to an aqueous thixotropic suspension with better physical stability.

The invention relates to the use of long-chain fatty acids, metal salts of fatty acids and clay, as thixotropic agents, to form stable liquid gel suspensions suitable for use as liquid detergent compositions for automatic dishwashers.

the present invention relates specifically to aqueous liquid detergent compositions for automatic dishwashing, having thixotropic properties, better film anti-formation properties and this physical stability, which are quickly dispersible in the washing medium to provide an efficient cleaning of dishes, porcelain cups and the like.

PREVIOUS TECHNICAL SPECIALTY

Commercially available detergents for domestic dishwashers, presented in powder form, have some disadvantages, eg, non-uniform composition, expensive operations necessary for their manufacture; tendency to jam in the warehouse at high humidity, resulting in the formation of clumps that are difficult to disperse; dust, a source of particular irritation for users suffering from allergies; and tendency to stick to the machine's dispensing device.

However, the liquid forms of the dishwashing compositions cannot generally be used in automatic dishwashers due to high foam levels, unacceptably low viscosities and excessively high alkalinity.

-5In addition, the powder detergents presently used often require a separate cleaning and manual drying step, with a cloth, of the plates, glasses, porcelain and the like, to eliminate the undesirable traces or film of precipitated calcium and magnesium salts.

The use of liquid detergent compositions presents other problems. Structuring salts sediment in the warehouse and are not easily redispersed. The compositions also often become thicker in storage and are not easily spilled.

Recent research and development activity has focused on the gel or thixotropic form of such compositions, however they have generally been shown to be insufficiently viscous to remain anchored in the dispensing cup of the washing machine and, furthermore, they leave residues in the form of stains, on plates, glasses, porcelain articles and the like.

Ideally, thixotropic cleaning compositions should be highly viscous at rest, have a Bingham plastic nature and have relatively high yield values.

When subjected, however, to shear stresses, such as when they are agitated in a container or ejs pressed through an orifice, they must fluidize quickly and, after cessation of the applied shear stress, quickly revert to the state of high viscosity / plastic nature of Bingham.

Stability is also of primary importance, that is, there should be no significant evidence of phase separation or absence of tightness after long rest.

For effective use, it is generally recommended that the automatic dishwashing detergent, hereinafter also referred to as DLA, contains (1) sodium tripolyphosphate (NaTPF) to soften or bind hard water minerals and to emulsify and / or peptize the sufficiency; (2) sodium silicate to provide the necessary alkalinity for effective detergency and to protect the contour and enamel of fine porcelain articles; (3) sodium carbonate, generally considered optional, to increase alkalinity; (4) a heat release agent to help remove dirt stains that lead to water staining; and (5) foam suppressor / surfactant to reduce foam, thus increasing the efficiency of the machine and providing the necessary detergency.

See for example SDÃ Detergents in Depth, Formulations Aspects of machine Dishwashing, Thomas Oberle (1974). The cleaning products that come close to the aforementioned compositions are, for the most part, liquids or powders.

In general, such compositions omit the hypochlorite-based bleaching agent, since it has a tendency to react with other chemically active ingredients, in particular the surfactant, thus degrading the suspending or thixotropic agent and impairing its effectiveness.

For this reason, U.S. Patent No. 3,985,668 describes abrasive degreasing cleaners of a gel-like consistency, containing (1) suspending agent preferably clay of the types smithite and atapulgite; (2) abrasive, eg, silica or perlite sand; and (3) filler consisting of low density powder polymers, expanded perlite and the like, which has a buoyant power and thereby a stabilizing effect on the composition in addition to functioning as a swelling agent, thereby replacing water otherwise available for formation of the undesirable supernatant layer due to the absence of tightness and destabilization of phases.

The above are the essential ingredients. Optional ingredients include hypochlorite bleaching agent, stable surfactant stable in the presence of the bleaching agent and buffer solution, eg, silicates, carbonates, and monophosphates.

Structurers, namely NaPTF, can be included as other optional ingredients, to provide or complete the structuring function not ensured by the Buffer Solution, not exceeding the amount of such structurer 5% of the total composition, according to the patent

Maintaining the desired levels of pH equal (or higher) to 10 is achieved by the components of the buffer / builder solution. A high pH is said to minimize the decomposition of the chlorine-based bleaching agent and the undesirable interaction between the surfactant and the bleaching agent.

When present, NaTPF is limited to 5%, as noted. No disclosure is made regarding a foam suppressor.

In UK Patent Applications GB 2,116,199A, and GB 2,140,450A, both assigned to ColgatePalmolive, liquid DLA compositions are disclosed that have desirably thixotropic, gel-like characterization properties and that include each of the various necessary ingredients for effective detergency with an automatic dishwasher.

The aqueous detergent composition, usually gel type for automatic dishwasher, having thixotropic properties, includes the following ingredients, on a weight basis:

(a) 5 to 35% alkali metal tripolyphosphate;

(b) 2.5 to 20% sodium silicate;

(c) 0 to 9% alkali metal carbonate;

(d) 0.1 to 5% of active water-dispersible organic detergent material, stable in the presence of chlorine-based bleaching agent;

(e) 0 to 5% stable foam suppressant in the presence of the chlorine-based bleaching agent;

(f) chlorine-based bleaching compound in an amount sufficient to provide about 0.2.

to 4% available chlorine;

(g) thixotropic thickening agent in an amount sufficient to provide the composition with a thyrotropic index of about 2.5 to 10; and (h) sodium hydroxide, when necessary, to adjust the pH.

The DLA compositions thus formulated are of low foaming; they are quickly soluble in the washing medium and highly effective at pH values that best lead to a better cleaning performance, viz., pH 10.5-13.5. The compositions usually have the consistency of the gel, that is, a highly viscous, opaque, ti material. icy powder, having a plastic nature of Bingham and, therefore, relatively high yield values.

Accordingly, a certain cutting force is required to initiate or increase the flow as it would be obtained in the stirring cup of an automatic dishwasher in operation.

Under these conditions, the composition is rapidly fluidized and easily dispersed. When the cutting force is interrupted, the fluid composition quickly reverts to a state of high viscosity and of a plastic nature of “Bingham very close to its previous consistency.

U.S. Patent 4,511,487 of April 16, 1985 describes a low foaming detergent paste for dishwashers. The composition is based on a mixture of finely divided hydrated sodium metasilicate, an active chlorine compound and a thickening agent which is a hectori schist silicate

A small amount of nonionic surfactant derivatives and alkali metal carbonates and / or hydroxides can be used.

A similar pending application, which is attributed to the common applicant, is the series n ° 816,535, filed on January 7, 1987, which is incorporated herein by reference. The equally pending application discloses an aqueous thixotropic detergent composition for automatic dishwashing, which contains a long-chain fatty acid as a thixotropic thickener.

ADVANTAGES OVER THE PREVIOUS TECHNIQUE OF SPECIALTY

The thixotropic aqueous liquid detergent compositions of the present invention overcome many of the problems of the prior art in the art associated with liquid and powder detergents.

Due to the addition of a small effective amount of an anti-film-forming silica agent to the composition, it is unnecessary to add a rinse aid and it is not necessary to clean and dry with cloth to obtain plates, glasses, cups and clean and shiny kitchen utensils.

The thixotropic aqueous liquid detergent composition has the additional advantages of being stable, of not settling in a warehouse, of being readily redispersible. The liquid compositions of the present invention are easily pourable, easy to measure and easy to place in dishwashers.

-11 Another and unexpected advantage of adding the anti-silica-based film-forming agent to the detergent formulation is the fact that silica inhibits the formation of brown spots in the dishwasher.

The brown stain results from the deposition of iron and / or manganese oxides in the machine.

The formation of brown spots is a particularly serious problem in areas of hard water. The silica in the formulation acts on iron and / or manganese in the washing water to prevent its deposition in the dishwasher, in the form of iron oxides and / or manganese.

OBJECTIVES OF THE PRESENT INVENTION

It is an object of the present invention to provide a thixotropic aqueous liquid detergent composition for automatic dishwasher, which has better anti-film properties.

It is another object of the invention to provide a thixotropic aqueous liquid detergent composition that is stable in the warehouse, easily pourable and readily dispersible in the washing water.

Another object of the invention is to present a method for washing dishes, glass, porcelain and the like in an automatic dishwasher, using a thixotropic aqueous liquid detergent composition, in which it is unnecessary to resort to a separate rinse.

It is yet another object of the invention to present a method for washing dishes, glass, porcelain and the like, in an automatic dishwasher, using an aqueous liquid detergent composition, whereby cups, plates, dishes and the like are used. machine-dried without leaving any residue or skin.

It is another object of this invention to provide stable thixotropic aqueous liquid detergent compositions, in particular detergent compositions for automatic dishwashers, incorporating in the aqueous suspension a small effective amount of a silica-based film-forming agent.

A smaller amount of a fatty acid, metal salt of a fatty acid and / or thixotropic clay-based thickener is also added to inhibit the sedimentation of the suspended particles and to prevent phase separation.

DESCRIPTIVE MEMORY OF THE INVENTION

These and other objectives of the invention, which will become more easily noticeable from the following descriptive memory of the invention and its forms of realization, are achieved by incorporating, in a composition of liquid liquid detergent, a small but effective amount of a silica-based film-forming agent.

The physical stability of the composition improves with the addition of a fatty acid, metal salt of a fatty acid and / or thixotropic thickener based on clay.

<< '-13-

More particularly, according to a specific and preferred embodiment of the invention, there is a detergent composition, usually of the gel type, for automatic dishwashers, in which about 0.5 to 5% of a silica-based anti-film agent.

The silica based film forming agent has a particle size of about 0.1 to 10 microns. In a preferred embodiment of the invention, a sufficient amount of a long-chain fatty acid or a metal salt of a long-chain fatty acid is added to the composition, or either of the above in admixture with a thixotropic thickener of clay to obtain a thixotropic index of about 2.5 to 10 and to inhibit sedimentation of suspended particles, namely alkali metal structuring salts, etc.

In accordance with this aspect, the present invention provides an aqueous liquid detergent composition, usually of a gel type, for automatic dishwasher, having thixotropic properties, which includes, on a weight basis:

(a) 5 to 35% alkali metal tripolyphosphate;

(b) 2.5 to 40% sodium silicate;

(c) 0.5 to 5% silica-based film anti-forming agent (d) 0 to 9% alkali metal carbonate;

-14 (e) 0.1 to 5% of active water-dispersible organic detergent material, stable in the presence of chlorine-based bleaching agent;

(f) 0 to 5% stable foam suppressant in the presence of the chlorine-based bleaching agent;

(g) chlorine-based bleaching compound in an amount sufficient to provide about 0.2% to 4% of available chlorine;

(h) the thixotropic thickener in an amount sufficient to provide a thixotropic index of about 2.5 to 10;

(i) 0 to 8% sodium hydroxide; and (j) water to be made up.

Also with regard to this specific aspect, the invention features a method for washing dishes in an automatic machine with an aqueous washing bath containing an effective amount of the liquid detergent composition of the automatic dishwasher (DLAL), as previously described.

In accordance with this aspect of the invention, the DLAL composition can be quickly poured into the dispenser cup of the automatic dishwasher and, in just a few seconds, will become thick, returning to its normal pasty or dry state. gel type to remain safe inside the dispensing cup until cutting forces are applied again, namely those developed by the water jet of the dishwasher.

The invention will now be described in more detail by means of its specific embodiments. The DLAL products of the previous disclosure, for example, in the aforementioned GB 2,116,199 A and GB 2,140,450 A, have rheological properties of the product, depending on the cutting speed.

The compositions exhibited a higher viscosity at a low cutting speed and a lower viscosity at a high cutting speed, indicating that there was an efficient fluidization and gelation well within the cutting speeds existing within a standard dishwasher.

In practical terms, this means better pouring and processing characteristics, as well as less lack of tightness in the machine's distribution cup, compared to previous liquid or gel DLA LL products.

For applied cutting speeds corresponding to 3-30 rpm, the viscosities (Brookfield) varied, correspondingly, from about 10,000 to 30000 cps to about 3000 to 7000 cps, as measured at ambient temperature using a Brookfield LVT viscometer after 3 minutes using a No. 2 spindle. A cutting speed of 7.4 sec ^-1 corresponds to a rpm of the spindle of about 3.

An approximate 10-fold increase in cutting speed produces a viscosity reduction of about 3 to 9 times. The compositions of the applicant's previous invention thus show plateaus fluidifications at significantly lower cutting speeds and of significantly greater extension in terms of increasing speeds of </ 2.

-16 cut versus increasing decrease in viscosity. This property of the DLAL products of the previous invention is summarized in terms of a thixotropic index (IT) ³ , which is the ratio of apparent viscosity at 3 rpm and 30 rpm.

The previous compositions have an IT of 2 to 10. DLAL compositions must show a quick and substantial return to the previous consistency in a resting state, when the cutting force is interrupted.

In terms of apparent viscosity, see. it was found that, since the viscosity at ambient temperature (22 ° + 1 ° C) measured on a Brookfield HATD viscometer, using a spindle number 4 at 20 rpm, is less than about 20000 cps, the The composition can be readily agitated so that a thixotropic composition can be easily fluidized or liquefied to allow the product to be delivered through a conventional compressible tube-shaped vial or other convenient dispensing device.

The present invention is based on the surprising discovery that substantially better anti-film properties can be achieved by adding a small effective amount of a silica-based film anti-film agent to the thixotropic aqueous liquid detergent composition.

Physical stability, that is, resistance to phase separation, sedimentation, etc., can be achieved by adding to the composition a small but effective amount of a thixotropic thickener and a stabilizing agent.

ANTI FILM FORMING AGENTS

The silica-based film-forming agent materials, which can be used, are either precipitated or exhaled natural or synthetic silica. Silica can be amorphous or crystalline.

The silica material that is used can contain up to about 0.1 to 5% alumina (A ^ Og), normally up to about 0.5 to 3%, and more usually about 1% alumina, based on silica weight.

A preferred silica material is Sy loid 244, which is amorphous silica, has a particle size of about 4 microns and is sold by W.R. Grace Co.

Another suitable silica material is Silox 15, also from W.R. Grace Co., which has a particle size of about 4 microns.

Another preferred silica material is Huber Zeo 49, which is amorphous silica and is sold by JM Huber Corporation and which contains about 1% alumina (A ^ Og) The presence of as little as 1% A ^ Og contributes to reduce hydrolysis and subsequent silica solubilide in the very alkaline detergent composition for automatic dishwashing.

The particle size of the silica material that is used is important to achieve the desired anti-film properties.

The silica particles used are. finely divided and can have a particle size of about 0.10 to 10 microns, preferably 0.50 to 8 microns and more preferably about 1.0 to 5.0 microns.

-18Silica particles of this size and in this amount used here are not abrasive.

The finely divided silica particles. in the dishwasher bath act as coagulants of protein particles in particles, keeping them in suspension to prevent them from settling on clean dishes.

The amount of silica-based film-forming agent that can be used to achieve the desired improvement in film formation will depend on the hardness of the water, the active detergent compound, the inorganic salts and other ingredients of the DLA. The silica-based anti-film agent is particularly effective in hard washing water of, for example, 300 ppm hardness or more.

The amount of silica-based anti-film agent used can be about 0.5 to 5%, preferably about 1 to 4% and more preferably about

1.5 to 3% by weight, based on the weight of the total composition.

THIXOTROPIC THICKENERS

The thixotropic thickeners or suspending agents, which can be used according to the present invention, to provide the aqueous medium with thixotropic properties, can be organic, for example, fatty acid or polyvalent metal salts of fatty or mate acid? inorganic clay materials that form colloids.

Thixotropic thickeners must be stable in the presence of high alkalinity and stable in the presence of chlorine-based bleaching compounds,

-13 namely sodium hypochlorite. Preferred thixotropic thickeners comprise fatty acids, polyvalent metal salts of fatty acids and inorganic clays, which form colloids, of the types smithite and / or atapulgite.

The amount of thixotropic thickener used will depend on the specific thickener used, but it should be added to the thickener formulation sufficient to provide the composition with a deitixotropic index of about

2.5 to 10.

Preferred thixotropic fatty acid thickeners are higher aliphatic monocarboxylic fatty acids, having from about 8 to about 22 carbon atoms, more preferably from about 10 to 20 carbon atoms, and most preferably from about 12 to 18 carbon atoms, including the carbon atom of the fatty acid carboxyl group.

The aliphatic radical can be saturated or unsaturated and can be linear or branched. Straight chain saturated fatty acids are preferred. Mixtures of fatty acids can be used, such as those derived from natural sources, mainly tallow fatty acid, coconut fatty acid, soy fatty acid, etc., or from synthetic sources resulting from industrial manufacturing processes.

Thus, examples of fatty acids that can be used as thickeners include, for example, decanoic acid, lauric acid, dodecanoic acid, palmetic acid, myristic acid, stearic acid, oleic acid, eicosanoic acid, tallow fatty acid, coconut fat, soy fatty acid and mixtures of these acids.

-20 Stearic acid and mixed fatty acids, eg coconut fatty acid, are preferred.

The amount of the fatty acid thickener required to obtain the desired values of thixotropy and physical stability will depend on factors such as the nature of the fatty acid, active detergent compound, inorganic salts, in particular TPF, other DLAL ingredients, as well as the conditions of advance storage and shipping.

Generally, however, the amounts of fatty acid thixotropic agent that can be used are in the range of about 0.03 to 0.5%, with a preference of about 0.03 to 0.2%, most preferably from about 0.05 to 0.15%, and provide the desired long-term stability and absence of phase separation.

The polyvalent metal salts of the above fatty acids can also be used in the present invention, as thixotropic thickeners. Suitable thixotropic thickeners of metal salts are disclosed in the previous application, series No. 903,924, filed on September 5, 1986, in the name of Drapier es al., Which is incorporated herein by reference.

The preferred metals are the polypalent metals, namely magnesium, calcium, aluminum and zinc. In general, metals can be present in the bivalent to pentavalent state. Preferably, the metal salts are used in their higher oxidation states.

^: L,

-21 As is evident, for DLAL compositions, as well as any other applications in which the composition of the invention is or may come into contact with articles used for the handling, storage or service of food products or that may otherwise come into contact with contact with, or be consumed by, people and animals, the metal salt should be selected taking into account the toxicity of the metal.

For this purpose, calcium and magnesium salts are particularly preferred as generally safe additives to foods.

Many of these metal salts are commercially available. For example, aluminum salts are in the form of tracids, e.g., aluminum rat as aluminum tri-stearate, O ^ -Η ^, COO) g. The monoacid salts, eg, aluminum mono-stearate, Al (OH ^ (C ^^ H ^^ COO) and diacid salts, eg, aluminum di-e-stearate, AHOfOC- ^ Hgj-COO ^ , θ mixtures of two or three of the mono-, di-, and tri-acid salts can be used for those metals, eg Al, with valences of +3 and mixtures of the mono- and diacid salts can be used for those metals, eg, Zn, with valences of +2.

It is more preferred that the diacids of metals with a valence of +2 and the triacids of metals with a valence of +3, tetra acids of metals with a valence of +4 and penta-acids of metals with a valence of +5 are used. in predominant quantities.

For example, at least 30%, preferably at least 50%, most preferably 80% to 100% of the total metal salt should be in the highest possible oxidation state, that is, each of the possible sites of

i v

-22valence is occupied by a fatty acid residue.

Metal salts, as mentioned above, are generally commercially available but can be easily produced by, for example, saponification of a fatty acid, eg animal fat, stearic acid, etc. or the corresponding fatty acid ester, if treated with a hydroxide or metal oxide ροΐ £ valente, eg in the case of aluminum salt, with alum, alumina, etc.

Preferred fatty acid polyvalent salt stabilizers are calcium stearate, i.e., calcium stearate, magnesium stearate, that is, magnesium distearate, aluminum stearate, that is, aluminum tri-stearate and stearate. zinc, that is, zinc distearate.

Metal salts of mixed fatty acids, such as naturally derived acids, eg coconut acid, as well as mixed fatty acids resulting from the commercial manufacturing process, are also used to advantage, as an inexpensive source , but effective, long-chain fatty acid.

The amount of fatty acid salt stabilizers required to obtain the desired increase in physical stability will depend on factors such as the nature of the fatty acid salt, the nature and amount of the thixotropic agent, active detergent compound, inorganic salts, in particular TPF, other ingredients of DLAL, as well as storage and forward shipping conditions.

-23's

However, in general, amounts of fatty acid polyvalent metal salt stabilizing agents in the range of about 0.02 to 1%, preferably about 0.06 to 0.8%, most preferably about 0 , 08 to 0.4%, provide long-term stability and absence of phase separation at rest or during transport at both low and high temperatures, as necessary for an eomercially acceptable product.

The conventional inorganic thixotropic clay thickeners can also be used in the present invention. Clay thickeners can be used in small amounts, in combination with fatty acid thickeners or in combination with polyvalent fatty acid metal salt thickeners. Clay thickeners, however, can be used per se, as thixotropic thickeners.

The preferred clay thickeners are made up of inorganic clays, which form colloids, of the types smethite and / or atapulgite.

Esmetite clays include montmorillonite (bentonite), hectorite, atapulgite, smetite, saponite, and the like. Montmorillonite clays are preferred and are sold under the trade names of Thixogel (Registered Trademark) No. 1 and Gelwhite (Registered Trademark) GP, H, etc., from Georgia Kaolin Company; and Eccagum (Registered Trademark) GP, H, etc., by Luthern Clay Products.

Atapulgite clays include materials sold under the trade name Altagel (Trade Mark), i.e. Altagel 40, Altagel 50 and Altagel 150 by Engelhard Minerais & Chemicals Corporation.

\, -24 Mixtures of the types of esmetite and atapulgite in weight ratios from 4: 1 to 1: 5 are also useful. Thickeners or suspending agents of the above types are well known in the art, as described, for example, in U.S. Patent No. 3,985,668 mentioned above. Abrasives or polishing agents should be avoided in DLAL compositions, as they can damage the surface of fine china, crystals, etc.

* When used in combination with fatty acids or polyvalent metal salts of fatty acids, thixotropic clay-based thickeners are used in quantities of 0.1 to 3%, preferably 0.1 to 2.5% and more preferably from 0.1 to 2%.

When clay-based thixotropic thickeners are used alone as a thixotropic thickener, they can be used in amounts of about 1.5 to 8%, preferably 2 to 5%, by weight, of the formulation.

₍ In general, the effectiveness of DLAL is directly related to (a) levels of available chlorine; (b) alkalinity; (c) solubility in washing medium; and (d) foam inhibition. It is preferable for this purpose that pH of the DLAL composition is at least 9.5, more preferably about 10.5 to 13.5, and more preferably at least about 11.5.

At relatively lower pH values, the DLAL product is too viscous, that is, similar to a solid, and thus not rapidly fluidizable at cutting force levels created within the dispensing cup under normal machine operating conditions.

Thus, the addition of NaOH is often necessary to increase the pH to levels within the above ranges and to increase the flow properties. The presence of carbonate is also often required for this purpose, as it acts as a buffer solution helping to maintain the desired pH level.

However, excess carbonate should be avoided as it may cause the formation of cat. acidified bonate, thereby impairing the stability, thixotropy and / or detergency of the DLAL product, and also impairing the product's dispersibility of, for example, compressible tube-shaped vials. Caustic soda (NaOH) also has the function of neutralizing the phosphoric or phosphonic acid ester foam suppressant, when present.

Typical amounts of about 0.5 to 3% by weight of NaOH and about 2 to 9% by weight of sodium carbohydrate in the DLAL composition are typical, although it should be noted that sufficient alkalinity can be provided by NaTPF and sodium silicate. NaTPF can be used in the DLAL composition in a range of about 8 to 35% by weight, preferably about 20 to 30% by weight, and should preferably be free of heavy metal that tends to decompose or inactivate the hypoclo preferred sodium rite and other chlorine-based bleaching compounds.

NaTPF can be anhydrous or hydrated, including stable hexahydrate with a hydration degree of 6, corresponding to about 18% by weight of water or more.

In fact, given the stability of hexahydrate, the presence of some hydration water is highly effective, serving, it is thought, to form seeds

-26 of the stable hexahydrate that delivers hydration and solubilization of the remaining NaTPF particles. If only hexahydrate is used, the detergent product can be too liquid. On the contrary, if only anhydrous NaTPF is used, the product may, in some cases, be too thick and therefore inappropriate.

Especially preferred DLAL compositions are obtained, for example, when using a weight ratio of 0.5: 1 to 2: 1 of anhydrous NaTPF to hexahydrate, with values of about 1: 1.

Foam inhibition is important to increase the efficiency of the dishwasher and to minimize the destabilizing effects that could occur due to the presence of excess foam inside the machine during washing. The foam can be sufficiently reduced by the appropriate selection of the type and / or amount of active detergent material, the main foam-producing component.

Foam grade is also somewhat dependent on the hardness of the washing water in the machine, so an appropriate adjustment of the proportions of NaTPF, which has a water softening effect, can contribute to providing the desired degree of foam inhibition. However, it is generally preferable to include a stable foam suppressant or inhibitor in the presence of the chlorine-based bleaching agent.

The phosphoric acid alkyl esters of the formula are particularly effective

-27ο

HO-P— ^R OR sold, for example, by BASF - Wyandotte (PCUK - PAC), and in particular the acidic phosphate alkyl esters of the formula

O "

HO — P —OR

I

OR sold, for example, by Hooker (SAP) and Knapsack (LPKN -158), where one or both R groups in each type of ester can independently represent an alkyl group ^c ^ 2_2 Mixtures of the two can be used types or any other types stable in the presence of the chlorine-based bleaching agent, or mixtures of mono- and di-esters of the same type.

Especially preferred is a mixture of mono- and dialkyl esters C ₁₆ -C _1g of acid phosphate, such as monostearyl / distearyl acid phosphates 1.2 / 1 (TKnapsack). When foam suppressors are used in the composition, proportions of 0.01 to 5% by weight, preferably 0.1 to 5% by weight, and in particular about 0.1 to 0.5%, are typical, by weight, the weight ratio of active detergent to foam suppressant varying generally from about 10: 1 to 1: 1 and preferably from about 4: J. to 1: 1.

Other foam suppressants that can be used include, for example, the known silicones.

Although any chlorine-based bleaching compound, such as dichloro-isocyanurate, dichloro-dimethylhydantoin, or chlorinated TSF can be used in the compositions of this invention, an alkali metal, eg sodium hypochlorite, is especially preferred , or potassium, lithium and magnesium. The composition should contain sufficient chlorine-based bleaching compound to provide about 0.2 to 4.0%, by weight, of available chlorine, as determined, for example, by acidifying 100 parts of the composition with excess hydrochloric acid.

A solution containing about 0.2 to 4.0% by weight of sodium hypochlorite contains or provides almost the same percentage of available chlorine. A solution containing about 0.8 to 1.6%, by weight, of sodium chloride, contains about 0.8 to 1.6%, by weight, of available chlorine, and is especially preferred.

For example, a sodium hypochlorite solution (NaOCl) with about 11 to about 13% available chlorine can be used to advantage, in amounts of about 3 to 20%, preferably about 7 to 12%.

sodium silicate, which provides alkalinity and protection of hard surfaces, namely enamel and fine porcelain contour, is used in an amount ranging from about 2.5 to 40% by weight, preferably about 10 to 35% by weight in the composition. The sodium silicate also protects the washing machine from corrosion.

At the higher levels indicated herein, for example, at levels greater than about 10% by weight, the silicate also provides a greater anti-scabbing action. Sodium silicate is generally added in the form of an aqueous solution, preferably having a Na2O: SiO2 ratio of about 1: 2.2 to 1: 2.8, for example, 1: 2.4.

Most of the other components of the composition, in particular NaOH, sodium hypochlorite and foam suppressant, can also be added in the form of an aqueous solution or dispersion.

The detergent active material useful for this purpose must be stable in the presence of the chlorine-based bleaching agent, in particular hypochlorite-based bleaching agent and those of the types of water-dispersible surfactants, anionic organic, oxide are preferred. amine, phosphine oxide, sulfoxide or betaine, the anionic ones mentioned above being most preferred.

They are used in amounts ranging from about 0.1 to 5%, preferably between about 0.3 and 20%. The surfactant agents particularly preferred for this purpose are the linear or branched mono- and / or di- (Cg) -alkyl-phenyl-oxide mono- and / or alkali metal disulfides, for example , DOWFAX (Trademark) 3B-2 and DOWFAX-2A-l.

In addition, the surfactant must be compatible with the other ingredients of the composition. Other suitable surfactant agents include primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates and sec-alkyl sulfates.

Examples include sodium alkyl iq_i8- ^{C su} 1fatos such as sodium dodecyl sulfate and sodium tallow alcohol sulfate and sodium alkane g_ ^ -C ^ g sodium sulfonates.

such as sodium hexadecyl-1-sulfonate and sodium ^{c 2} x- ^18-18 and sodium ^zene -sulfonates, such as sodium dodecyl-benzene-sulfonates.

The corresponding potassium salts can also be used. Like other suitable surfactants, or detergents, amine oxide surfactants are typically of the structure Ι ^ κΝΟ, where each R represents a lower alkyl group, for example, methyl, and represents an alkyl group of long chain having from 8 to 22 carbon atoms, for example a lauryl, myristyl, palmityl or cetyl group.

Instead of an amine oxide, a corresponding surfactant, phosphine oxide RR ^ PO or sulfoxide RR ^ SO, can be used. The surface-active betaine i ^z you agents are typically of the structure _R2 R N RCOO-wherein each R represents a lower alkylene group having 1 to 5 carbon atoms.

Specific examples of these surfactants are lauryl dimethylamine oxide, myristyl dimethyl amine oxide, the corresponding phosphine oxides and sulfoxides, and the corresponding betaines, including dodecyl dimethyl ammonium acetate, diethyl tetradecyl pentanoate -ammonium, hexadecyl-dimethyl-ammonium hexanoate and the like.

For reasons of biodegradability, the alkyl groups in these surfactants should be linear, with such compounds being preferred.

Surfactants of the foregoing type, all well known in the art, are described, for example, in U.S. Patent Nos. 3,985. 668 and 4,271,030.

The amount of water contained in these positions must, of course, neither be so high as to produce unduly low viscosity and fluidity, nor so low as to produce unduly high viscosity and reduced fluency, in both cases being reduced or destroyed. thixotropic properties. Such a quantity is easily determined by routine experimentation in any specific case, usually ranging from about 25 to 75% by weight, preferably about 50 to 65% by weight.

The water must also be deionized or softened. These amounts of water in the composition include water added as parts of the liquid solutions of other ingredients, but do not include water bound, for example, that of NaTPF hexahydrate.

These conventional compositions or other ingredients may be included in small amounts, generally less than about 3% by weight, such as perfume, hydrotropic agents such as benzene, toluene, xylene and sodium cumene sulfonates, preservatives, dyes, pigments and the like, of course all being stable in the presence of chlorine bleaching compound and high alkalinity (properties of all components).

As dyes, chlorinated phthalocyanines and aluminosilicate polysulphides are especially pre-injected which provide pleasant green and blue colors, respectively.

-32The liquid DLA compositions of this invention are easy to use, in the known way to wash dishes, glasses, glasses, kitchen utensils and the like, in an automatic dishwasher, equipped with a suitable detergent dispensing device, in a washing bath. aqueous solution containing an effective amount of the composition.

In a preferred embodiment of the invention, the liquid dishwashing liquid detergent composition is formulated using the ingredients mentioned below.

Component

Percentage by weight

Alkali metal tripolyphosphate

Sodium silicate (47.5%)

Anti-silica film-forming agent

Alkali metal carbonate (anhydrous)

Active organic detergent material, dispersible in water, stable in the presence of chlorine-based bleaching agent

Stable foam suppressor in the presence of chlorine-based bleaching agent

Bleaching compound based on sodium hypochlorite

Thixotropic fatty acid thickener Sodium hydroxide (50%)

- 25

- 40

1- 4

2- 8

0.5 - 3

0.10-3

0.2 - 4

0.03 - 5

2-6

Water to make up

The thixotropic aqueous liquid detergent compositions for automatic dishwashing of the present invention can contain the conventional additives of dishwashing detergent compositions.

The formulations can be prepared with commercially available solid powder builders and / or the ingredients can be mixed and the formulations subjected to grinding to obtain the desired particle size.

The invention can be practiced in several ways and a number of specific embodiments will be described to illustrate the invention, with reference to the accompanying examples.

All amounts and proportions referred to herein are percentages by weight of the composition, unless otherwise specified.

the present invention is further illustrated by the following examples.

-34Example 1

A thixotropic aqueous liquid detergent composition is formulated for automatic dishwashing. from the following ingredients, in the quantities indicated.

Component Weight percentage

Deionized Water 26.26

Knapsack Foam Suppressor

LPKN-158 ⁽¹⁾ 0.16

Sodium hydroxide (50%) 5.00

Sodium carbonate (anhydrous) 5.00

Sodium tripolyphosphate (anhydrous) 20.00

2.00 «silica-based film-forming agent?

Thixotropic thickener of stearic acid 0.10 Surfactant DOWFAX 3B-2 0.80

Sodium hypochlorite (11%) 9,10

Sodium silicate (1 / 2.23 - 47%) 31.58

100.00 (D Mixture of mono- and distearyl-alkyl esters () of phosphoric acid, mol ratio 1: 1.3.

(2)

Silica Syloid 244 has a particle size of about 4 microns and is sold by W.R. Grace Co.

(3)

Na mono- and didecyl diphenyl disulfonate (45% solution).

* »

stearic acid is melted and the ingredients are added to the water generally in the order mentioned, under gentle stirring, until a homogeneous mixture is obtained. The formulation is tested, washing glasses and dishes at 55 ° C (130 ° F) in hard water (300 ppm hardness) in an automatic dishwasher and it was found that the dishes were washed and dried they had no apparent film.

Example 2

To demonstrate the effect of adding the silica-based film anti-forming agent, formulations are prepared with and without the silica-based film anti-fusion agent and compared to a powder detergent composition. commercially available.

The compositions are formulated containing the following ingredients:

Component

-36Silica based anti-film agent

Anti-film forming agent without silica

Deionized water 32.05 34.55 Foam suppressor LPKN-158 Knapsack 0.16 0.16 Sodium hydroxide (50%) 5.00 5.00 Sodium carbonate (anhydrous) 5.00 5.00 Sodium tripolyphosphate (anhydrous) 20.00 20.00 Anti-formation agent silica-based film (Syloid 244) 2.50 - Thixotropic thickener of stearic acid 0.10 0.10 Surfactant DOWFAX 3B-2 0.80 0.80 Sodium hypochlorite (11%) 9.10 9.10 Sodium silicate (1 / 2.23-47%) 25.29 25.29 100.00 100.00 The stearic acid is fused and the dients are added to the usually in the order indicated. under gentle agitation, until get a homogeneous mixture. The formulation is subjected to test , washing glasses at 55 ° C (130 ° F) in hard water (300 ppm of toughness).

’Χ

The two previous formulations (A) and (B) were tested and compared with a commercially available automatic dishwasher powder formulation (C). The formulations were tested in a Kenmore automatic dishwasher, following the procedure described in ASTMD 3566-79, with the exception of using only four washing cycles.

The formation of film and spots was evaluated according to the following scales:

Film forming scale

1. Very good, with no visible film.

2. Slight film formation, becoming apparent.

3. Visible film, increasing.

4. Continuous increase of significant film.

5. Film formation becoming excessive.

6. High film formation, excessive formation.

7. Continuous increase of excessive film.

Scale of stain formation

A - Very good - no stains

B - Very few apparent stains

C - Different

D - Significant coverage of approximately 50%.

The results obtained in the fourth cycle. are shown in Table I below.

-38 TABLE 1

Formulation evaluation of Performance Stains Pelicula (A) Anti-formation agent silica-based film B-C 1-2 (B) Anti-formation agent silica-free film B-C 5-6 (C) Commercial detergent in powder B-C 4-5

Example 3

The formulation of compositions of. thixotropic aqueous liquid detergents for automatic washing of dishes from the following ingredients, in the quantities indicated.

I

-39 (D) (Ε

Anti-for- agent Anti-for- agent

film mation Component based on silica} film mation without silica Deionized water 32,638 34,638 Green pigmentGraphtol 0.002 0.002 Foam suppressor LPKN-158 Knapsack 0.160 0.160 Sodium hydroxide (50%) 5,000 5,000 Sodium carbonate (anhydrous) 5,000 5,000 Sodium silicate (1 / 2.35-43.5%) 25,300 25,300 Sodium tripolyphosphate (anhydrous) 20,000 20,000 Anti-formation agent silica-based film ⁽¹⁾ 2,000 - DOWFAX 3B-2 surfactant ⁽²⁾ 0.800 0.800 Stearic acid 0.100 0.100 Sodium hypochlorite (11%) 9,000 9,000 100,000 100,000 (1) Asilica (Huber Z and 0 49) contains about 1% alumina

(Al ^ O ^) and has a particle size of about 9 microns.

(2 )

Na mono and didecyl-di-phenyl disulfonate (45% solution)

Emersoll32 sold by Emery Company.

(3)

-400 stearic acid is melted and the ingredients are added to the water, usually in the order indicated, with gentle stirring, until a homogeneous mixture is obtained

The formulations are tested, washing glasses and plates at a temperature of approximately 55 ° C (130 ° F) in hard water (300 ppm hardness). The two formulations were tested and compared with a commercial powder detergent (F) formulation for automatic dishwashing.

The formulations were tested on a Kenmore machine, using the procedure described in ASTMD 3566-79, with the exception that only four wash cycles were used. The evaluation of stain and film formation was carried out, as in Example 2, and the results obtained in the fourth cycle are shown below in Table 2.

TABLE 2

Performance evaluation

Film Stains (D) Anti-formation agent

Silica-based film B-C (E) Anti-film forming agent, without silica B-C (F) Commercial powder detergent

B-C

1-2

5-6 «

-41Example 4

A thixotropic aqueous liquid detergent composition for automatic dishwashing is formulated from the following ingredients, in the amounts indicated.

Component Weight percentage

Deionized water 38.79 Thixotropic thickener based on aluminum stearate 0.25 Thixotropic thickener based on clay (Pharmagel H) 1.25 Sodium silicate (1 / 2.4-47.5%) 17.73 Sodium tripolyphosphate (anhydrous) 12.00 Sodium tripolyphosphate (hexahydrate) 12.00 Silica-based film-forming agent 2.00 Sodium carbonate (anhydrous) 5.00 Sodium hypochlorite (11%) 7.61 Agent surfactant DOWFAX 3B-2 0.80 Foam suppressor 0.16 Sodium hydroxide (50%) 2.40 Graphitol Green 0.01

100.00

1: 1 mix of LPKN-158 and PCUK-PAE.

(1)

-42The ingredients are mixed in the conventional manner or are mixed according to the procedure of the common and also pending allocation request, series n ° 903.924, filed on September 5, 1986, which is incorporated herein by reference.

The formulation is tested, washing glassware at approx. 55 ° C (130 ° F) in hard water (300 ppm hard) in an automatic dishwasher. The washed and dried glass dishes were found to be free of film.

The thixotropic aqueous liquid detergent compositions for automatic washing of dishes. this invention has better anti-film properties.

The invention is not limited to the previous description and the examples are given by way of illustration only. The invention must be interpreted in accordance with the appended claims.

Claims (14)

claims 1 ^. - Process for the preparation of a thixotropic aqueous liquid detergent composition of the gel type for automatic dishwashing, characterized in that at least one ingredient from the group consisting of organic detergent, bleaching agent, structuring agent is included in the said composition. detergents, sequestering agent, foam inhibitors, and mixtures thereof, of about 0.5 to 5% of a silica-based film-forming agent and an amount of a thixotropic thickener sufficient to provide a thixotropic index of about in 2.5 to 10. 2nd - Process according to claim 1, characterized in that the amount of the silica-based anti-foaming agent is in the range of about 1 to 4%. 3a, _ Process for the preparation of an aqueous thixotropic liquid composition for an automatic dishwasher, characterized in that it includes in the said composition, by weight, in approximate values: (a) 5 to 35% of detergent builder; (b) 2.5 to 40% sodium silicate; (c) 0.5 to 5% silica-based anti-foaming agent having a particle size of about 0.1 to 10 microns; (d) 0 to 9% alkali metal carbonate; (e) 0.1 to 5% of active organic detergent material, dispersible in water, stable in the presence of chlorine-based bleaching agent; (f) 0 to 5% stable foam suppressant in the presence of the chlorine-based bleaching agent; (g) chlorine bleach compound in an amount sufficient to provide about 0.2 to 4% of available chlorine; (h) an amount of a thixotropic thickener sufficient to provide a thixotropic index of about 2.5 to 10. (i) 0 to 8% sodium hydroxide; (j) water to be made up. 4th. Process according to claim 3, characterized in that the thixotropic thickener consists of a long chain fatty acid in an amount of about 0.03 to 0.5%. 5th. - Process according to claim 3, characterized in that the thixotropic thickener consists. into a polyvalent metal salt of a long chain fatty acid in an amount of about 0.02 to 1.0%. 6th. Process according to claim 4, characterized in that a thixotropic thickener based on clay is also included in the said composition, in an amount of about 0.1 to 3.0%. -45 \ .. 7§. Process according to claim 5, characterized in that a thixotropic thickener based on clay in an amount of about 0.1 to 3.0% is also included in said composition. 8th. Process according to claim 3, characterized in that the anti-silica-based film-forming agent has a particle size of about 0.5 to 8.0 microns. 9â. - Process for the preparation of a thixotropic aqueous liquid composition for an automatic dishwasher, characterized in that it includes in the said composition, by weight, in approximate values: (a) 5 to 35% alkali metal tripolyphosphate; (b) 2.5 to 40% sodium silicate; (c) 1 to 4% silica-based film-forming agent having a particle size of about 0.5 to 8.0 microns; (d) 0 to 9% alkali metal carbonate; (e) 0.1 to 5% of active organic detergent material, dispersible in water, stable in the presence of chlorine-based bleaching agent; (f) 0 to 5% stable foam suppressant in the presence of the chlorine-based bleaching agent; (g) chlorine-based bleaching compound in an amount sufficient to provide about 0.2 to 4% of available chlorine. -46 (h) an amount of a thixotropic thickener sufficient to provide a thixotropic index of about 2.5 to 10; (i) 0 to 8% sodium hydroxide; and (j) water to be made up. lOã. - Process according to claim 8, characterized in that the silica-based anti-foaming agent contains about 0.1 to 5% alumina, based on the weight of silica. llá. - Process according to claim 8, characterized in that the silica has a particle size of about 1 to 5 microns. 12th. Process according to claim 8, characterized in that the thixotropic thickener consists of a long-chain fatty acid having C C to C2Q carbon atoms in an amount of about 0.03 to 0.20%. 13á. _ Process according to claim 8, characterized in that the thixotropic thickener consists of a polyvalent metal salt of a long-chain fatty acid having C ^g carbon atoms in an amount of about 0.06 to 0.8% . 14á. - Process according to claim 13, characterized in that the polyvalent metal is aluminum, calcium, zinc and magnesium. Λ · 9 $ ¢ -. -Μ 15a, - Process according to claim 12, characterized in that a thixotropic thickener based on clay in an amount of about 0.1 to 2.5% is also included in said composition. 16th. Process according to claim 13, characterized in that an apixila-based thixotropic thickener is also included in said composition in an amount of about 0.1 to 2.5%.