CN1471568A - Granular detergent composition with improved solubility - Google Patents

Abstract

A granular detergent composition comprising from about 0.01% to about 50% by weight of an anionic sulphonate surfactant, from about 0.01% to about 455 by weight of a hydrotrope, and from about 0.55 to about 5% by weight of a cationic surfactant. The granular detergent composition is substantially free from anionic sulphate surfactant. The granules are optionally coated with water soluble material. Process for preparing the granular detergent composition.

Description

Granular detergent composition with improved solubility

technical field

The present invention relates to a granular detergent composition and a method of producing the same. More particularly, the present invention relates to granular detergent compositions having improved solubility.

Background technique

Recently, the detergent industry has shown considerable interest in laundry detergents that possess the convenience, aesthetics and solubility of liquid laundry detergent products while retaining the cleaning performance and low cost of granular detergent products. Past granular detergent compositions have had certain problems with aesthetics, solubility and ease of use. These problems have been exacerbated by the advent of "compact" or low dosage granular detergent products and liquid laundry detergents which are generally insoluble in wash solutions. These low-dosage detergents are currently in high demand as they save resources and can be sold in small packages, making them more convenient for consumers to purchase. However, compared to liquid laundry detergents, which can be simply poured from a bottle rather than scooped out of a box and sprinkled into the wash solution, granular detergents are inferior in that they can be dispensed into a washing machine. too convenient.

As noted above, such low dosage or "compact" detergent products also sometimes suffer from dissolution problems, especially in cold laundry solutions (ie, below about 30°C). More specifically, poor dissolution leads to the formation of "coagulums," what appear to be white solids that remain in the washing machine or on washed clothes after a traditional wash cycle. These "agglomerates" are especially common in cold wash conditions and when the order of adding to the washing machine is laundry detergent first, then clothes, and finally water (often called "reverse order of addition" or "ROOA") . Such undesirable "agglomerates" also form when consumers add clothes, detergent, and finally water to the washing machine. Such agglomeration can lead to incomplete dispensing of detergent in washing machines equipped with dispensing drawers or other dispensing devices such as granulettes. In this case, an undesired result is residues of undissolved detergent in the dosing device.

The cause of the above dissolution problems is generally related to the "bridging" of "gel-like" substances between the surfactant-containing particles to form undesirable "agglomerates". However, from the standpoint of cleaning performance, surfactants are one of the most important ingredients in detergent compositions. If the surfactant content is reduced, although the dissolution problem can be avoided, the cleaning performance of the product will be affected.

It can be seen that there remains a need for a granular detergent having improved solubility with little or no loss of cleaning performance.

Summary of the invention

The present invention relates to a granular detergent composition comprising from about 0.01% to about 50% by weight of an anionic sulfonate surfactant, from about 0.01% to about 45% by weight of a hydrotrope and from about 0.5% to about 5% by weight of a cationic surfactant . The granular detergent composition is substantially free of anionic sulphate surfactants.

The granular detergents of the present invention provide improved solubility even in cold water with little or no loss of cleaning performance.

The above and other features, aspects and advantages of the present invention will become apparent to those skilled in the art after a study of the present disclosure and the appended claims.

A detailed description

The following are definitions of terms used in this article.

"Comprising" means that other steps and other ingredients can be added that do not affect the end result. The term encompasses the terms "consisting of" and "consisting essentially of".

All percentages given are by weight of the total composition unless otherwise indicated.

All references cited are hereby incorporated by reference in their entirety. Citation of any reference is not an admission that it is available as prior art to the invention as defined by the claims.

Various aspects of the product of the present invention are described in detail below.

Anionic Sulfonate Surfactant

Anionic sulfonate surfactants are an essential ingredient of the granular detergents of the present invention. Preferred anionic sulfonate surfactants include salts (or optionally acids) of the following: C5-C20 linear or branched alkylbenzene sulfonic acids, alkyl ester sulfonic acids, C6-22 primary or secondary alkanes Sulfonic acids, C6-C24 olefin sulfonic acids, sulfonated polycarboxylic acids, alkyl glycerol sulfonic acids, preferably derived from alcohols derived from tallow or coconut oil, fatty acid glycerol sulfonic acids, fatty oleyl glycerol sulfonic acids and their mixtures.

The cation of the anionic sulfonate surfactant may be any suitable cation, eg sodium, potassium, hydrogen, ammonium or an alcoholamine, preferably sodium or potassium.

More preferably, the anionic sulfonate surfactant of the present invention is selected from C11～13 branched or linear alkylbenzene sulfonic acid (LAS), C6～22 primary or secondary paraffin sulfonic acid (PS), C10 Sodium or potassium salt of C6-C24 olefin sulfonic acid (AOS) of ~18 methyl ester sulfonic acid (MES).

Anionic sulfonate surfactants are present in the granular detergent compositions at levels of from about 0.01% to about 50%, preferably from about 20% to about 50%, more preferably from about 20% to about 45% by weight of the granular detergent .

The granular detergent compositions of the present invention are substantially free of anionic sulphate surfactants. "Substantially free of anionic sulfate surfactants" means in the present invention that the level of anionic sulfate surfactants is less than about 0.001%, preferably less than about 0.0001%, more preferably 0%.

Hydrotrope

Hydrotropes are an essential ingredient of the granular detergent compositions of the present invention. Detergent granules comprising linear alkylbenzene sulphonates as surfactants tend to gel when in contact with water and the viscous gel surrounding the granules causes the granules to stick to each other and form agglomerates. While not intending to be bound by theory, it is believed that the hydrotrope changes the phase behavior of the sulfonate surfactant into a less sticky, less viscous phase and more rapidly solubilizes the sulfonate surface during washing active agent, thereby substantially avoiding the formation of coagulum or residue during the washing process.

Other suitable hydrotropes are described in known publications, eg, Mitijevic, Surface and Colloid Science, Plenum Press, Vol. 15 (1993), the disclosure of which is incorporated herein by reference.

Preferably, the hydrotropes of the present invention include sulfonic acids, sulfonate salts, polyethylene glycols, polypropylene glycols, and mixtures thereof.

Preferred ionizing salts are the alkali metal, alkaline earth metal, alkylamine and ammonium salts of sulfonic acids. More preferred salts are selected from sodium, potassium, monoethanolamine sulfonates and mixtures thereof.

More preferably, the hydrotrope is selected from the group consisting of sulfonic acids and sulfonates of lower chain aromatics, polyethylene glycol, polypropylene glycol and mixtures thereof.

Preferred sulfonates as hydrotropes of the present invention are sodium xylene sulfonate, sodium toluene sulfonate, sodium cumene sulfonate, alkyl diphenyl ether disulfonic acids with alkyl chain lengths C1 to C10, and their mixture.

Hydrotropes are present in the granular detergent compositions of the present invention at a level of from about 0.01% to about 45%, preferably from about 0.1% to about 15%, more preferably from 0.2% to about 10% by weight of the granular detergent composition.

cationic surfactant

Cationic surfactants are an essential ingredient of the granular detergent compositions of the present invention. Cationic surfactants are believed to have two functions in improving the cleaning performance of the granular detergent product: penetration of the surfactant on the soil and hardness tolerance. Anionic sulfonate surfactants have a negative charge, while soils generally have a positive charge. As a result, anionic sulfonate surfactants do not penetrate soil as well as positively charged cationic surfactants. Also, during washing, anionic sulfonate surfactants tend to precipitate by forming complexes with hardness ions in the water such as calcium and magnesium. Then, the cleaning performance of the granular detergent composition decreases. However, combinations of cationic and anionic surfactants tend to form micelles. Since the micelles do not interact with hardness ions, anionic sulfonate surfactants do not precipitate. Thus, the cleaning performance of the granular detergent composition is no longer degraded.

Preferred cationic surfactants are quaternary ammonium surfactants. Preferred quaternary ammonium surfactants are selected from single C6-C16, preferably C6-C10 N-alkyl or alkenyl ammonium surfactants, wherein the remainder of N is substituted with methyl, hydroxyethyl or hydroxypropyl groups . Another preferred cationic surfactant is a C6-C18 alkyl or alkenyl ester of a quaternary ammonium alcohol, such as a quaternary ammonium chloride ester.

More preferably, the cationic surfactant has the general formula: Wherein R1 is a C8-C18 hydrocarbon group and a mixture thereof, preferably a C8-14 alkyl group, more preferably a C8, C10 or C12 alkyl group, and X is an anion, preferably chlorine or bromine.

Cationic surfactants are present in an amount from about 0.5% to about 5%, preferably from about 1% to about 5% by weight of the granular detergent composition.

method

The granular detergent compositions of the present invention can be prepared according to a process comprising the steps of: (a) mixing an anionic sulfonate surfactant, a hydrotrope and a cationic surfactant; (b) adding other detergent ingredients, and (c) The detergent mixture from step (b) is dried.

Step (a) is mixing the anionic sulfonate surfactant, the hydrotrope and the cationic surfactant, with water, if desired. The purpose of adding the hydrotrope is to change the phase structure of the sulfonate surfactant. It is preferred that the anionic sulfonate surfactant is mixed with the cationic surfactant, followed by the addition of the hydrotrope, since the anionic sulfonate surfactant and the cationic surfactant form ion-pair complexes. The detergent granules preferably comprise anionic sulfonate surfactant to hydrotrope in a ratio of from about 50:1 to about 1:1, preferably from about 25:1 to about 5:1. Hydrotrope.

In step (b), other detergent ingredients are added, including builders such as carbonates, silicates, zeolites or brighteners.

Step (c) preferably comprises spray drying of the mixture obtained from steps (a) and (b) to produce granules. These particles can be compacted and ground in a roller compactor to increase density. Spray drying can be carried out in conventional spray drying equipment such as conventional towers as well as in other spray drying equipment. Conventional spray drying equipment may include, for example, spray dryers supplied by Ohkawara Corporation (Japan) or Niro Corporation (Denmark). For drying detergent granules, conventional spray drying equipment typically has a height of about 0.5 m to about 30 m and an internal temperature of about 200°C to about 500°C.

Examples of the spray drying process of the present invention are described in US Patent 5,149,455, Jacobs et al., issued September 22, 1992, and US Patent 5,565,442, Del Greco et al., issued October 15, 1996, which are incorporated herein by reference.

The mixture paste comprising anionic sulfonate surfactant, cationic surfactant and hydrotrope from step (a) may be agglomerated prior to step (c). In this agglomeration process, the paste from step (a) is fed into a mixer or densifier (eg Lodige Recycler CB30 and Lodige Recycler KM300 "Ploughshare") for agglomeration. A preferred method of agglomeration is disclosed in US Patent 5,366,652, Scott et al., issued April 28, 1992, incorporated herein by reference.

Additional ingredients/methods

clad

The granular detergent compositions of the present invention are optionally coated with a water soluble coating material selected from the group consisting of anionic sulphonate surfactants, hydrotropes and mixtures thereof.

The granular detergent compositions of the present invention are preferably coated with a water-soluble coating material as follows: (d) sending the detergent granules to a coating mixer; (e) providing the coating mixer with a water-soluble coating material; and ( f) at least partially coating the granules in a coating mixer to form a coated granular detergent composition.

Optional step (d) is to send the detergent granules from step (c) of the present invention to an overcoat mixer, eg a high or medium speed mixer, followed by an optional low or medium speed one. Alternatively coating may be performed in a single mixer which may be at low, medium or high speed. A mixer specifically for use in the present invention should include comminution and grinding as well as agglomeration means so that both techniques can be performed simultaneously in a single mixer.

The residence time of the mixer will vary with the type of mixer and operating parameters. In the case of the preferred high-speed mixer, the average residence time is between about 0.1 and 60 s, more preferably between about 0.1 and about 30 s, still more preferably between 0.1 and about 15 s. Other preferred conditions for the high-speed mixer include a tip speed of about 3 to 90 m/s, more preferably a tip speed of about 10 to 70 m/s, and a power consumption of about 0.005 W/kg to 100 W/kg, more preferably A power consumption of about 0.05W/kg to 80W/kg is preferred. Preferably, if a pulverizer is used, the pulverizer can be used inside the mixer to break up unconvincing oversized particles at a rotational speed of about 0-5000 rpm, more preferably about 100-3000 rpm. Preferably, the wall temperature is from ambient temperature to about 80°C and the gap between the mixer elements and the wall is between about 0.1 cm and 25 cm. An example of a high speed mixer with an average residence time in the range of about 0.1 to about 60 seconds is the Lodige Recycler CB 30 ^(TM) manufactured by Lodige, or a mixer manufactured by Drais, Schugi, or a similar brand of mixer.

In the case of the preferred medium speed mixer, the average residence time is from about 30 to 1800 s, more preferably from about 30 to about 1200 s, more preferably from about 30 to about 600 s. Other preferred conditions for a medium speed mixer include a tip speed of about 0.1 to 30 m/s, more preferably a tip speed of about 1 to 25 m/s, and a power consumption of about 5 W/kg to 1000 W/kg, more preferably about 20W/kg～500W/kg power consumption. Preferably, if a pulverizer is used, the pulverizer can be used inside the mixer to break up unconvincing oversized particles at a rotational speed of about 0-5000 rpm, more preferably about 100-4000 rpm. Preferably, the wall temperature is from about -20°C to about 80°C and the gap between the mixer elements and the wall is from about 0.1 cm to 25 cm. Examples of moderate speed mixers with an average residence time between about 30 and 1800 s are the Lodige Recycler KM "Ploughshare" 300 ^TM and 600 ^TM or Drais KT 160 ^TM mixers from Lodige, or mixers from Fukae. A particularly preferred mixer is a Lodige KM "Ploughshare" 600 ^™ medium speed mixer comprising a horizontal, hollow, stationary cylinder internally and centrally mounted with a rotating shaft around which are secured a number of plow-like paddles. Preferably, the rotational speed of the shaft is from about 15 rpm to about 140 rpm, more preferably from about 80 rpm to about 120 rpm. In a preferred mixer, grinding and comminution is accomplished by cutter knives, which are usually of small size and whose shaft rotates preferably at a speed of about 3600 rpm.

In a preferred low speed mixer, the average residence time is from about 30 s to about 1800 s, more preferably from about 30 s to about 1200 s, even more preferably from about 30 s to about 600 s. The tip velocity is preferably in the range of about 0.1 m/s to about 10 m/s, more preferably about 0.2 m/s to about 7 m/s, even more preferably about 0.2 m/s to about 3.5 m/s. Examples of preferred low-speed mixers include drum agglomerators, drum agglomerators, pot agglomerators, fluidized bed granulators, and extruders. Examples of extruders are multi-screw extruders manufactured by Werner-Pfliedder (Germany).

In a preferred embodiment it was found that step (c) can be carried out under the described process parameters in a Lodige Recycler KM ^TM (Ploughshare) medium speed mixer, Lodige CB ^TM high speed mixer or Fukae, Drais, Schugi blender, or a similar brand of blender, to complete successfully. The preferred LodigeRecycler KM ^™ (Ploughshare) medium speed mixer for use as a mixer in the present invention consists of a horizontal, hollow, stationary cylinder with a centrally mounted rotating shaft around which are fixed several plow-like paddles. Other mixers of similar nature suitable for use in the process include the Lodige Ploughshare ^(TM) mixer and the Drais ^(R) KT 160 mixer.

Optional step (e) is aimed at providing a water soluble coating material into the coating mixer. The water soluble coating material is selected from anionic sulfonate surfactants, hydrotropes and mixtures thereof. As explained above, the anionic sulfonate surfactant and the hydrotrope are added in step (a). However, additional anionic sulfonate surfactants and hydrotropes can be added during this step. Preferably, the water-soluble coating material is an anionic sulfonate surfactant and a hydrotrope in a ratio of about 95:5 to about 5:95, more preferably about 50:1 to about 1:1 mixture.

Optional step (f) is at least partially coating the granules from step (e) and obtaining a granular detergent composition according to the invention.

granularity

Granular detergent compositions herein preferably comprise at least about 50% by weight of particles having a geometric mean particle diameter of from about 400 microns to about 1500 microns and preferably having a geometric standard deviation of from about 1 to about 2. Preferably, the geometric standard deviation is from about 1.0 to about 1.7, preferably from about 1.0 to about 1.4. The granular detergent composition produced by the method may comprise undersized or fine particles, wherein "fine particle" is defined as having a geometric mean particle diameter smaller than the selected geometrical particle diameter of the granular detergent composition at a given geometric standard deviation. Particles approximately 1.65 standard deviations below the mean particle diameter. Oversized or large particles may also be present, where "large particles" are defined as particles having a geometric mean particle diameter at a given geometric standard deviation greater than about 1.65 standard deviations above the selected geometric mean particle diameter for granular detergent compositions. The fine particles are preferably separated from the granular detergent composition and returned to the process by feeding them to at least one mixer and/or fluid bed dryer, as described below. Likewise, large particles are preferably separated from the granular detergent composition and fed to a grinder, whereby their geometric mean particle diameter is reduced. After the geometric mean particle diameter of the large particles has been reduced, the large particles are returned to the process by feeding them to at least one mixer and/or fluid bed dryer.

other ingredients

The granular detergent compositions of the present invention may also comprise a wide variety of ingredients including, but not limited to, optical brighteners, pigments or dyes, chelating agents, nonionic surfactants, pH control agents, detergency builders, fillers and mixture of these materials. Especially preferred are pigments or dyes such as titanium dioxide, bluing agents such as copper sulfate, zinc thiosulfate and ultramarine blue, glitter enhancers such as mica flakes, fillers such as sodium carbonate and sodium sulfate and co-builders such as citrates and Nonionic surfactant.

The granular detergent composition may also contain bleach, bleach activators, enzymes, perfume, uncoated detergent granules and a variety of other ingredients to produce a fully formulated detergent composition.

Such suitable ingredients are disclosed and exemplified in US Patent 5,756,444, issued May 26, 1998 to Scott et al., and in US Patent 5,478,503, issued December 26, 1995 to Ronald. The entire disclosures of these references are incorporated herein by reference.

The various aspects and embodiments of the invention presented herein provide numerous advantages, including improved solubility, with little or no degradation in cleaning performance.

The following examples further describe and demonstrate preferred embodiments within the scope of the present invention. The purpose of giving the examples is only for illustration, and should not be regarded as a limitation to the present invention, because there are many variations of the present invention without departing from the spirit and scope of the present invention.

Example

Example 1~8

% by weight

1 2 3 4 5 6 7 8 LAS ^* 30 30 30 20 25 25 25 25S×S ^** 4 2 1 4 2 1 3 3 polyethylene glycol 0.1 - 0.1 0.1 0.5 0.1 0.5 0.5CocoK3 2 2 2 2 2 1 1 1 Brightener 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 Sodium carbonate 20 20 20 20 30 20 30 30 Zeolite A 5 5 5 10 5 5 10 10 Acrylic acid-maleic acid 10 10 10 10 10 10 10 10 Copolymer silicate 15 15 15 15 0 15 0 0 Coating material LAS - 6 - 6 6 6 6 6SXS - - 3 2 1 0.5 0.5 - Polyethylene glycol - - - - - - - 3 Sodium percarbonate 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2NOBS ^*** 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 Spices 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Protease 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Other Make up to 100%

^* 40% linear alkylbenzene sulfonate paste

^** 20% sodium xylene sulfonate solution

^*** Sodium nonanoyloxybenzenesulfonate (bleach activator)

Claims (10)

1. A granular detergent composition comprising: (a) from about 0.01% to about 50% by weight of an anionic sulfonate surfactant; (b) from about 0.01% to about 45% by weight hydrotrope; and (c) from about 0.5% to about 5% by weight cationic surfactant, wherein the granular detergent composition is substantially free of anionic sulfate surfactant. 2. The granular detergent composition of claim 1, wherein the detergent composition comprises from about 20% to about 50% by weight of anionic sulfonate surfactant. 3. The granular detergent composition of claim 1, wherein the anionic sulphonate surfactant is selected from the group consisting of sodium linear alkylbenzene sulphonate, MLAS (methyl alkyl benzene sulphonic acid), PS (paraffin sulphonic acid), MES (methyl ester sulfonic acid), AOS (olefin sulfonic acid) or mixtures thereof. 4. A granular detergent composition according to claim 1, wherein the detergent composition is coated with a water soluble coating material selected from the group consisting of anionic sulfonate surfactants, hydrotropes and mixtures thereof. 5. A granular detergent composition according to claim 4, wherein the water soluble coating material comprises a hydrotrope selected from the group consisting of polyethylene glycol, polypropylene glycol, sulphonates and mixtures thereof. 6. The granular detergent composition of claim 4, wherein the hydrotrope is selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate, sodium cumene sulfonate, alkyl dialkyl groups with chain lengths C1 to C10 Phenyl ether disulfonates, and mixtures thereof. 7. The granular detergent composition of claim 4, wherein the water-soluble coating material is anionic sulfonate surfactant and hydrotrope in a ratio of anionic sulfonate surfactant to hydrotrope of about 95:5 ~A mixture of about 5:95. 8. The granular detergent composition of claim 4, wherein the detergent composition has a geometric mean particle diameter of from about 400 microns to about 1500 microns with a geometric standard deviation of from about 1 to about 2. 9. A process for preparing the granular detergent composition of claim 1, comprising the steps of: (a) mixing an anionic sulfonate surfactant, a hydrotrope and a cationic surfactant; (b) adding other detergent ingredients; and (c) drying the detergent mixture from step (b). 10. The method of claim 9, further comprising the steps of: (d) sending the detergent granules to a coating mixer; (e) providing a water-soluble coating material to the coating mixer; and (f) at least partially coating the granules in a coating mixer to form a coated detergent granular composition.