EP0395976A1 - Pasty, phosphate-free, effectively water-free detergent - Google Patents

Abstract

The concentrated detergent paste substantially free of water and containing no phosphate contains (A) 2 to 7 % wt. sodium alkylbenzole sulphonate with linear C9-13 alkyl chains, (B) 20 to 40 % wt. non-ionic tensides with linear alkyl or alkylene groups with 10 to 18 C atoms, (C) 35 to 65 % wt. synthetic, fine-crystalline, water-containg zeolith of type NaA, (D) 3 to 15 % wt. of at least one organic polycarboxylate builder (related to free acids), (E) 0 to 20 % wt. alcaline washing agents of the sodium carbonate and sodium silicate class, (F) 0 to 5 % wt. of a suspension stabiliser and (G) other common detergent components. The sum of components (C) and (D) should not exceed 70 % wt. and the setting point of component (B) should be below 10 DEG C.

Description

The present invention relates to a pasty, phosphate-free, essentially water-free detergent, which is distinguished by high storage stability and improved dispersibility and solubility in water.

Pasty detergents have the advantage over powdered agents that they can be handled and dosed without dust. They are therefore also suitable for automatic dosing devices. Their problem is that they must be sufficiently flowable over a wide temperature range, which considerably limits the freedom from recipes, especially if high proportions of solid active ingredients are to be incorporated into the paste. On the other hand, it is required that the agents do not separate during storage, which is difficult to reconcile with the requirement for good flowability and a correspondingly reduced viscosity. Furthermore, the aim is not to use solvents and suspension stabilizers, since they do not contribute to the washing performance when used. After all, when cold water is added, especially during the washing-up process in the washing machine, they should not form tough, difficult-to-disperse gels, but should dissolve quickly and completely. This danger arises in particular when the agents contain high proportions of nonionic surfactants.

DE 12 79 878 (GB 12 05 711) describes a pasty, essentially anhydrous agent, the liquid phase of which consists of nonionic surfactants and lower alcohols. Sodium tripolyphosphate (TPP) and soda are used as skeleton salts and sodium perborate monohydrate as bleaching agent. In order to prevent the pastes from segregating during storage, the solids are finely ground and suspension stabilizers in the form of finely divided silica are additionally added to the agent. DE 22 33 771 (US 38 50 831) discloses washing pastes which contain mixtures of nonionic surfactants and polyols as the liquid phase and phosphates, citrate and nitrilotriacetate as the structural salts. Also water glass, i. H. a weakly alkaline-reacting silicate with the composition Na₂O: SiO₂ 1: 3.3 may be present.

No. 4,115,308 describes pasty detergents which can be anhydrous and in this case contain large proportions of solvents, such as triethanolamine, polyethylene glycol or free fatty alcohols. These additives do not contribute to the washing effect of the agents. The majority of the pastes also contain tripolyphosphate in proportions of 32 to 35% by weight. The paste-like compositions according to DE 28 25 218 (US Pat. No. 4,316,812) are also extremely phosphate-rich with fractions of 30 to 35% by weight Na tripolyphosphate. As a dispersion stabilizer, the agents contain finely divided silicon dioxide in proportions of approximately 2% by weight. Phosphate-free detergent pastes, which, however, contain high proportions of water-soluble builder substances which are also problematic for environmental reasons, such as nitrolotriacetate or phosphonates (between 38 and 55% by weight) are known from DE 2 054 866. In addition, the agents contain larger proportions of alcohols as a solvent and small amounts of soap in the form of the alkali or alkaline earth metal salts as a suspension stabilizer.

EP 30 096 teaches that in liquid to pasty detergents, the solids, consisting of skeleton salts and persalts, have to be ground to particle sizes below 10 μm in order to avoid segregation of the pastes during storage. The skeleton salts consist essentially of polyphosphonates. Alkali silicates and organic builder salts can also be present, but no further details are given here. The surfactant component consists exclusively of liquid non-ionic surfactants. Anionic surfactants are not included in the pastes. The need to grind the solids to a very small grain size requires a considerable amount of equipment and time.

The paste-like agents mentioned essentially contain phosphates as builder salts. In the interest of minimal wastewater pollution, however, an extensive absence of phosphates is desirable. P-free detergents, however, require a different overall concept compared to P-containing detergents in order to avoid a decrease in cleaning power. This development is already well advanced for powder detergents, while for pasty agents the problems are much greater due to the limited choice with regard to the usable raw materials. Particular problems arise with pastes in which the phosphate is to be replaced by zeolite. These are particularly difficult to disperse in cold water because of the water insolubility of the zeolites. The experience gained with phosphate-containing agents can therefore not be easily transferred to liquid concentrates containing phosphate-free, high proportions of zeolite.

EP 295 525 describes a pasty detergent which does not flow under the influence of gravity, and a method for automatic Dosing this agent in the washing machine known. As a liquid component, the agent contains nonionic surfactants and builder salts dispersed therein. The high viscosity of the agents and their tendency to form viscous, difficult to disperse gels when mixed with cold water requires the use of mechanical conveying and dispersing devices, such as pumps, agitators and injectors, as well as process control. Although they enable a high degree of automation, exact dosing and trouble-free operation, they also require corresponding investments.

It was therefore the task of developing a phosphate-free liquid detergent which is resistant to segregation and whose viscosity or flowability is selected so that it can be metered without the use of apparatus. Furthermore, the agent should be quickly and completely dispersible and soluble in cold water without the formation of tough and poorly dispersible gels.

• A) 2 bis 7 Gew.-% an Natrium-Alkylbenzolsulfonat mit linearen C₉₋₁₃-Alkylketten,
• B) 20 bis 40 Gew.-% an nichtionischen Tensiden mit linearen, 10 bis 18 C-Atome aufweisenden Alkyl- oder Alkenylgruppen,
• C) 35 bis 65 Gew.-% an synthetischem, feinkristallinem, wasser­haltigem Zeolith vom Typ NaA,
• D) 3 bis 15 Gew.-% mindestens eines organischen Polycarboxylat-­Builders (bezogen auf freie Säure),
• E) 0 bis 20 Gew.-% an Waschalkalien aus der Klasse Natriumcarbonat und Natriumsilikat,
• F) 0 bis 5 Gew.-% eines Suspensionsstabilisators, mit der Maßgabe, daß die Summe der Bestandteile (C) und (D) 70 Gew.-% nicht übersteigt.

The invention with which these objects are achieved is a pasty, phosphate-free, essentially water-free detergent concentrate, characterized by a content of

• A) 2 to 7 wt .-% of sodium alkylbenzenesulfonate with linear C₉₋₁₃ alkyl chains,
• B) 20 to 40% by weight of nonionic surfactants with linear alkyl or alkenyl groups having 10 to 18 carbon atoms,
• C) 35 to 65% by weight of synthetic, finely crystalline, water-containing zeolite of the NaA type,
• D) 3 to 15% by weight of at least one organic polycarboxylate builder (based on free acid),
• E) 0 to 20% by weight of washing alkalis from the class sodium carbonate and sodium silicate,
• F) 0 to 5% by weight of a suspension stabilizer, with the proviso that the sum of the components (C) and (D) does not exceed 70% by weight.

The water content of the compositions is less than 4% by weight, preferably less than 2% by weight. According to this definition, water is considered free, i.e. H. not as water of hydration or water bound to zeolite.

The viscosity of the agents is generally between 10.00 and 70,000 mPa · s, preferably 15,000 and 60,000 mPa · s and in particular up to 50,000 mPa · s (milli-Pascal x sec.). The agents are thus still flowable and can be metered by hand, but on the other hand can also be fed to the washing machines by means of automatic metering and washing devices.

The proportion of Na-alkylbenzenesulfonate (component A), which is generally referred to in industry as dodecylbenzenesulfonate, is preferably 3 to 6% by weight.

Component (B) consists of alkoxylated, preferably ethoxylated, linear alcohols or their mixtures with alcohols (oxo alcohols) having 8 to 18 carbon atoms which are methyl-branched in the 2-position. Alcohols with 8 to 16 carbon atoms are preferably saturated. Those with 18 carbon atoms are preferably unsaturated and consist, for example, of oleyl alcohol. The number of ethylene glycol ether groups (EO) is 2 to 10, preferably 3 to 8 and should preferably be coordinated with respect to the alcohol residue in such a way that the ethoxylates or ethoxylate mixtures have a pour point of less than 10 ° C., preferably less than 5 ° C. Particularly suitable Nonionics from this class are C₁₀₋₁₄ coco alcohols with 3 - 8 EO, oley alcohol with 5 - 10 EO, C₁₀₋₁₄ oxo alcohols with 3 - 8 EO and C₁₂₋₁₅ oxo alcohols with 3 - 7 E0, as well as their mixtures.

Alcohol alkoxylates of the general formulas R- (EO) _a - (PO) _b - (EO) _c and R- (PO) _x - (EO) _y - (PO) _z in the EO for an ethylene glycol ether radical are also useful, PO for a propylene glycol ether residue, a for numbers from 1 to 10, b for numbers 1 to 3, c for the numbers 0 to 10 with (a + c) = 5 to 15, x for the numbers 1 to 3, y for the numbers 3 to 10 and z stand for the numbers 0 to 3 with (x + z) = 1 to 4. Preferred nonionics of this class are oleyl alcohol with 1 - 2 PO and 4 - 8 EO, C₈₋₁₂-oxo alcohol with a = 2 to 6, b = 1 to 2 and c = 2 to 6 and C₁₀₋₁₄-oxo alcohols or C₁₀₋ ₁₄ fatty alcohols with x = 1 to 2 and y = 5 to 12 according to the formulas above. Likewise, the aforementioned ethoxylates and alkoxylates can be mixed with one another in any manner.

The proportion of the surfactant component (B) is on average 20 to 40% by weight, preferably 25 to 35% by weight. The total amount of surfactants is 20 to 35% by weight, preferably 22 to 33% by weight.

Component (C) consists of hydrated, finely crystalline, synthetic zeolite of the NaA type. Suitable zeolites have practically no particles larger than 30 μm and preferably consist of at least 80% of particles smaller than 10 μm. Their calcium binding capacity, which is determined according to the information in DE 24 12 837, is in the range from 100 to 200 mg CaO / g. The zeolite content of the agent is hydrated based on zeolite, 35 to 65% by weight, preferably 37 to 60% by weight and in particular 50 to 57% by weight.

Suitable polycarboxylates to be assigned to component (D), which can be used either alone or in a mixture, are monomeric polycarboxylates, such as citric acid and nitrilotriacetic acid (NTA) in the form of the sodium salts. If only citric acid is used, its proportion (based on acid) is preferably 8 to 15% by weight. If only NTA is used, its proportion (based on acid) is preferably 3 to 10% by weight.

Preferred components of component (D) are polymeric or copolymeric carboxylic acids in the form of the sodium salts. Suitable homopolymers are polymethacrylic acid and preferably polyacrylic acid, for example those with a molecular weight of 800 to 200,000. Of particular interest are low molecular weight, low-viscosity polyacrylic acids which do not adversely affect the fluidity of the liquid concentrates, but at the same time still have sufficient sequestering capacity. Such polyacrylic acids have a molecular weight of 1,000 to 50,000. They are present in the compositions as sodium salts, although mostly not all acid groups are neutralized. The polyacrylic acid content of the agents can be 3 to 10, preferably 4 to 8,% by weight, based on acid.

Suitable copolymers are those of acrylic acid with methacrylic acid or copolymers of acrylic acid, methacrylic acid or maleic acid with vinyl ethers, such as vinyl methyl ether or vinyl ethyl ether, furthermore with vinyl esters, such as vinyl acetate or vinyl propionate, acrylamide, methacrylamide and with ethylene, propylene or styrene. In such copolymeric acids in which one of the components has no acid function, the proportion thereof in the interest of sufficient water solubility is not more than 60 mole percent, preferably less than 50 mole percent. Copolymers of acrylic acid or methacrylic acid with maleic acid, such as are characterized, for example, in EP 25 551-B1 have proven to be particularly suitable. These are copolymers which contain 50 to 90% by weight of acrylic acid or methacrylic acid and 50 to 10% by weight of maleic acid. Copolymers in which 60 to 85% by weight of acrylic acid and 40 to 15% by weight of maleic acid are present are particularly preferred. The content of such (co) polymers in the compositions, based on free acid, can be up to 10% by weight, preferably 3 to 8% by weight.

Anhydrous soda and sodium silicate are suitable as washing alkalis (component E). The sodium silicate can have a Na₂O: SiO₂ ratio of 1: 0.9 to 1: 3.5. Waterglass with a ratio of 1: 2 to 1: 3.5 and metasilicate with a ratio of 1: 1 to 1: 1.5 are preferred. The proportion of washing alkalis is 0 to 20, preferably 0 to 10% by weight, the proportion of soda preferably being up to 10% by weight and that of sodium silicate preferably up to 7% by weight.

Optionally, suspension stabilizers (component F) can be added to the agents in proportions of up to 5% by weight, preferably from 0.2 to 3% by weight. Alkaline soaps are suitable, in particular sodium soaps from fatty acids having 12 to 22 carbon atoms, preferably saturated C₁₄₋₁₈ fatty acids. Also suitable are finely divided silica, such as precipitated or thermally produced silica (Aerosil) or diatomaceous earth. Mixtures of soap and finely divided silica can also be used.

Further optional components are cellulose ethers with graying-inhibiting action, such as sodium carboxymethyl cellulose and their mixtures with other cellulose ethers, such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose or mixed ethers, such as methyl hydroxyethyl cellulose, methyl carboxymethyl cellulose or ethyl hydroxyethyl cellulose. Cellulose ethers and (co) polymers can advantageously be used together. The graying inhibitor content of the agents can be up to 1.5% by weight, preferably up to 0.5% by weight.

Further optional components are enzymes, in particular proteases, amylases and their mixtures, fragrances and customary optical brighteners, in particular optical brighteners with substantivity for cellulose fibers (cotton) from the class of the substituted bis-triazinylstilbene disulfonic acids and the sulfonated distyryle, which are customary in proportions of 0.05 to 0.5% by weight.

In addition, agents for improving the flowability can also be added. These include known hydrotropes, such as alkylbenzenesulfonate with 1 to 3 carbon atoms in the alkyl groups, such as toluene, cumene or xylene sulfonate. In contrast to the C₉₋₁₃ alkylbenzenesulfonates, however, they contribute nothing to the detergency of the agents and are therefore less preferred. Solvents such as lower alcohols and ether alcohols and polyethylene glycols with a molecular weight of 200 to 1,000 can also be used. The proportion of polyglycols can be up to 10% by weight. Alcohols can be used in the same amount, but they are less preferred.

The water content of the agents should be as low as possible, since free water increases the viscosity of the agents and thus makes processing and metering the agents more difficult. Water contents of less than 3% by weight, in particular less than 1.5% by weight, are therefore particularly preferred.

The agents are produced by mixing and homogenizing the solid, finely divided constituents with the liquid nonionic surfactants, in particular with the liquid surfactant mixture. Surprisingly, it was found that about half of the solid alkylbenzenesulfonates behave like liquid constituents and thus favor the incorporation of high solids contents. At the same time, they lower the viscosity of the agents or enable higher proportions of solids. They also improve the dispersing properties of the agents in cold tap water. The mixture is expediently ground while the constituents are combined or subsequently, for example in a colloid mill or on a roller mill, so that the particle size of the suspended solids is less than 50 μm, preferably between 5 and 40 μm. The proportion of coarse particles (over 80 µm) should preferably be less than 5% by weight.

The agents are generally used in a concentration of 4 to 12 g / l, preferably 5 to 10 g / l, with suitably softened, i.e. H. to a degree of hardness of less than 2 ° dH, in particular less than 1 ° dH, softened water is used to prepare the wash liquor.

The agents are characterized by a high washability and a low, non-disturbing foam development during use. Surprisingly, it has been shown that the agents are extremely stable against segregation even under prolonged storage under changing climatic conditions and dissolve and distribute completely within a short time even at water temperatures of 5 ° C.

Examples

The composition of the compositions, based on non-aqueous constituents, is shown in Table 1. It means:
ABS = sodium salt of a linear C₁₀₋₁₃ alkylbenzenesulfonic acid (average alkyl chain length C _11.8 )
OA-6 = oxo alcohol C₁₂₋₁₃ with 6EO
OA-424 = oxo alcohol C₁₀₋₁₃ with 4EO, 2PO and 4EO CO-16 = cetyl oleyl alcohol with 65% oleyl alcohol + 1PO + 6EO

The Na silicate had the composition Na₂O: SiO₂ = 1: 2.4. The polyacrylate had a molecular weight of 5,000. The copolymer was composed of acrylic acid and maleic acid (3: 1) and had a molecular weight of approximately 70,000. Both polymer salts were used in the form of the Na salts. The Na citrate was present as a dihydrate. The NaA type zeolite had a water content of 20%. The Na salt of 4,4′-bis- (2-anilino-4-morpholino-1,3,5-triazin-6-yl-amino) -stilbene-2,2′-disulfonic acid was used as the optical brightener. The soap consisted of a sodium tallow soap. The silica designated SiO₂ consisted of diatomaceous earth. The enzyme consisted of a protease-amylase mixture (3: 2). The unbound water content was less than 0.5% by weight. The contents given in the table mean percentages by weight. In the case of component (B), the acid content is given in brackets. example component component 1 2nd 3rd 4th A SECTION 5.0 6.0 3.0 5.0 B OA 6 3.9 3.9 3.7 4.0 OA 422 25.3 25.6 27.3 - CO 16 - - - 25.0 C. Zeolite 57.0 55.9 37.3 51.1 D Polyacrylate 6.1 6.2 - - (Acid) (5.2) (5.3) Citrate - - 18.6 - (Acid) (12.1) Copolymer - - - 5.0 (Acid) (4.4) E Na silicate - - 5.0 - soda - - - 5.0 F Soap - - - 2.0 SiO₂ - - 2.0 - opt. Brightener 1.0 0.8 1.0 1.0 enzyme 1.3 1.2 1.7 1.5 Perfume 0.4 0.4 0.4 0.4

• Beispiel 1: 42 000 mPa·s
• Beispiel 2: 49 000 mPa·s
• Beispiel 3: 29 000 mPa·s
• Beispiel 4: 32 000 mPa·s

The viscosity determined with a rotary viscometer at 20 ° C was:

• Example 1: 42,000 mPa · s
• Example 2: 49,000 mPa · s
• Example 3: 29,000 mPa · s
• Example 4: 32,000 mPa · s

The agents proved to be stable in storage, ie there was no discernible sedimentation within a period of 6 weeks. The solution rate at 4.5 ° C and 21 ° C determined under standardized conditions was excellent. The following percentages of 10 g paste, stirred into 1 liter water, were dissolved after 2 minutes and 5 minutes: 4.5 ° C 21 ° C 2 min. 5 min. 2 min. example 1 95.9% 100% 100% Example 2 94.8% 100% 100%

Claims (6)

1. Pasty, phosphate-free, essentially water-free detergent concentrate, characterized by a content of A) 2 to 7 wt .-% of sodium alkylbenzenesulfonate with linear C₉₋₁₃ alkyl chains, B) 20 to 40% by weight of nonionic surfactants with linear alkyl or alkenyl groups having 10 to 18 carbon atoms, C) 35 to 65% by weight of synthetic, finely crystalline, water-containing zeolite of the NaA type, D) 3 to 15% by weight of at least one organic polycarboxylate builder (based on free acid), E) 0 to 20% by weight of washing alkalis from the class sodium carbonate and sodium silicate, F) 0 to 5% by weight of a suspension stabilizer, G) and other usual detergent ingredients with the proviso that the sum of the ingredients (C) and (D) does not exceed 70% by weight. 2. Composition according to claim 1, characterized by a content of 3 to 6 wt .-% of component A. 3. Composition according to one or more of claims 1 and 2, characterized by a content of 25 to 35 wt .-% of component B, which has a pour point of below 10 ° C, preferably below 5 ° C. 4. Composition according to one or more of claims 1 to 3, characterized by a content of 37 to 60 wt .-% of component C. 5. Composition according to one or more of claims 1 to 4, characterized by a content of 3 to 10 wt .-% based on acid, of homopolymeric and copolymeric acrylic acid. 6. A process for the preparation of the compositions according to one or more of claims 1 to 5, characterized in that the mixture of the constituents is comminuted to a particle size of the solids below 50 µm.