JPH0672238B2 - Method for producing thixotropic detergent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention One feature of the present invention is that it contains dissolved tripolyphosphate, silicate and alkali metal ions and dispersed non-swelling clay thickener (preferably attapargas clay). The present invention relates to a thixotropic aqueous dishwasher detergent comprising a liquid phase of water and a solid phase which is mainly sodium tripolyphosphate. The composition also preferably contains a chlorine bleach (preferably dissolved sodium hypochlorite) and a bleach-resistant anionic surfactant, preferably an alkali metal carbonate.

Prior Art U.S. Patent Application Serial No. 497,615 discloses several compositions of this type, the entire disclosure of which is incorporated by reference.

(Problems to be Solved by the Invention and Means for Solving the Problems) The composition contains a certain proportion of a water-soluble potassium compound such as a potassium salt (or KOH), and the weight ratio of K: Na is about 0.0.
It has been found that at 4 to 0.5, preferably about 0.07 to 0.4, for example about 0.08 or about 0.15, significantly improved results are obtained. The resulting product is undesirably thickened or aged (a) at, for example, 37.8 ° C (100%).
ge) is much more stable in that it has less tendency to separate when subjected to. Also, when a certain portion of the sodium salt is replaced with the corresponding potassium salt of the same weight, the viscosity (eg, viscosity measured at 25 ° C., 20 rpm using a Brutsk Field HATD viscometer # 4 spindle) is significantly reduced and left (eg It is more stable to separation at room temperature) and inhibits the growth of relatively large crystals during storage. The reduced viscosity makes it easier to handle in the production plant, easier to dispense during use and because the consumer can easily destroy the thixotropic structure of the product (by shaking the packaging). Allows easy injection into detergent cups of household automatic dishwashers.

For product formulation, the ingredients and proportions described in the aforementioned US patent application Serial No. 497,615 can be used.
The proportions of the components of the set in the application are approximately as follows by weight.

(A) 8 to 35% of alkali metal tripolyphosphate (b) 2.5 to 20% of sodium silicate, (c) 0 to 9% of alkali metal carbonate, (d) Water-dispersible organic active substance stable to chlorine bleach detergent
0.1 to 5%, (e) Chlorine bleaching stable defoamer 0 to 5%, (f) Chlorine bleaching compound, amount to give about 0.2 to 4% chlorine, and (g) Thixotropic thickener , Thixotropic index about
Sufficient to give a composition of 2.5 to 10.

In the compositions disclosed herein, the proportion of sodium tripolyphosphate is 15% or more (more preferably about 20-25 or
30% range), the proportion of sodium silicate is at least about 4
% (Eg in the range of about 5 to 10 or 15%), the proportion of alkali metal carbonate is about 2 to 6 or 7%, the proportion of chlorine bleach is 0.5% or more chlorine (eg about 1 to 2% chlorine).
The ratio of active substance detergent is 0.1 to 0.5
It is preferably within the range of%. A preferred proportion range for sodium silicate is about 3.5 in the composition, calculated as SiO _2.
To 7%.

The proportion of water measured with a "Cenco" moisture meter (heating the sample with an infrared lamp until a constant weight) is approximately 40-50
% Range is preferred, about 43-48%, for example about 44% or
46% is more preferable.

The pH of the compositions disclosed herein is typically greater than 11 or 12. In one preferred formulation, the pH when the composition is diluted to 0.75% with water is in the range of about 10.7 to 11.3.

The compositions disclosed herein are preferably formulated to have a viscosity of less than about 8,000 centipoise (measured using a Brutz Field HATD viscometer # 4 spindle at 25 ° C. and 20 rpm), preferably about 2,000 or 3,000 to 7,000. Even more preferred are formulations that give a viscosity in centipoise, for example about 4,000 to 6,000 centipoise. Viscosity and other properties are preferably measured several days after the composition has been adjusted (eg, one week),
Shake the sample before measuring the viscosity and adjust the viscometer before reading the value.
It's actually good to move it for 90 seconds.

The composition disclosed herein has a yield value of 200 dynes / cm ² or more, preferably about 1100 dynes / cm ² or less, and is preferably blended to give a yield value of about 300 dynes / cm ² or more, about 900. More preferably, it is less than or equal to dynes / cm ^2, for example about 400 to 600 dynes / cm ² . The yield value is a measure of the shear rate at which the thixotropic structure breaks. This is Haake
e) Measured on an RV12 or RV100 rotational viscometer with an MVIP spindle at 25 ° C., the shear rate increases linearly from 0 to 20 sec ⁻¹ in 5 minutes (5 minutes after rest). In the Haake viscometer, a thin layer of material is subjected to shear forces between a rotating cylinder and the intimate cylindrical wall of the surrounding container. 1-3 are graphs obtained when the products of the three examples were tested in this way, with peak Y indicating the yield value.

Another factor measured by the Haake viscometer described above is the extent to which the composition restores its thixotropic structure. According to one measurement method, after increasing the shear rate for 5 minutes as described above, the rotation was reduced to zero for 5 minutes, and then 30
After a resting period of seconds, the spin is accelerated again to bring the shear rate from zero to 22.6 sec ^-1 in 5 minutes. This method yields a second yield value, the peak Yr in FIG. This second (recovered) yield value is preferably at least 200 dynes / cm ² , 50%, 75% or more of the initially determined yield value.

FIG. 4 is a photograph of the composition of Example 4. (Photographed on the scale shown in the drawing) The present invention will be further described in the following examples.

In the examples, Attagel # 50 is an attapulgite viscosity powder (Engelhard Minerals & Chemicals).
According to the company's catalog, it contains about 12% by weight of free moisture at the time of manufacture (measured by heating at 104.4 ° C (220 ° F)),
The BET surface area is about 210 m ² / g calculated on a dry basis. ), Graphtol Green is a colorant, and LPKN158 is an American House company.
House (Knapsack) defoamer, a 2: 1 mixture of mono- and di- (C ₁₆ -C ₁₈ ) alkyl esters of phosphoric acid, a silicic acid with a Na ₂ O: SiO ₂ ratio of 1: 2.4. Contains sodium,
Dowfax 3B2 is a 45% aqueous solution of sodium monodecyl / didecyldiphenyl oxide disulfonate, a bleach-resistant anionic surfactant.
Is sodium tripolyphosphate. ST unless otherwise specified
PP is added as a finely divided commercial anhydrous substance, its water content is about 0.5%, and such material usually has about 4.5-6.5% thereof.
Exists as pyrophosphate. Unless patented, the water used is ion-exchanged water.

Example 1 The following ingredients were added to a vessel in the following order while mixing with a conventional propeller type laboratory stirrer. The temperature and mixing time at each stage are also shown below.

The viscosity of this mixture was measured as described above at 37.8 ° C (10
After aging at 0 ° F for 3 weeks, it is about 5000 centipoise, and after aging at 37.8 ° C (100 ° F) for 3 months, the viscosity is about 4800.
It was a centipoise.

The STPP hexahydrate of this example had the following particle size distribution. USS sieve % # 10 on 0 # 40 on 0 # 100 on 25.4 # 200 on 31.5 # 325 on 16.5% 325 passing 25.9 Example 2 The following formulation was prepared and its properties were measured by the methods described below.

Water, colorant, clay, half of phosphate, defoamer, hypochlorite, sodium carbonate, potassium carbonate, NaOH, silicate,
The components were mixed in the order of the second half of phosphate, surfactant.

Capillary drainage time is a normal test and
atman) Draw a circle of 6.8 cm diameter on a 15 cm diameter sheet of size 41 paper and place a plastic ring (3.5 cm inside diameter, 4.2 cm outside diameter, 6.0 cm height) vertically on the paper concentric with the circle. ,
The test composition is filled in the ring. The liquid from the composition is absorbed by the paper and gradually spreads out towards the circle drawn. The time elapsed until the liquid came into contact with the circle was measured at three predetermined points and the average value was calculated.

Example 3 The components were mixed in the order shown below to prepare the following ingredients. The composition was then centrifuged at 275 G and continued until the volume of the clear separating liquid (continuous) phase did not increase and the resulting liquid was analyzed.

That is, the composition is identical except for the K: Na ratio.

The viscosity of the product of this example was measured at 80 ° F. (26.7 ° C.) with a Brutkfield RVT viscometer spindle No. 5.

Examples 4-6 below illustrate new and useful methods for making the above products (containing a certain amount of potassium). This method comprises other products of the type shown in the aforementioned U.S. patent application Serial No. 497,615 (no potassium compound present), as well as fine particles of a water-soluble inorganic builder salt dispersed in water containing a dissolved builder salt,
It can also be used to make other detergent slurries containing clay or other colloidal thickeners and surfactants. In these examples (the particles of builder salt in the product are mostly STPP hexahydrate plus sodium carbonate hydrate), a very viscous (e.g. viscosity of 20.000-60.000 cps) constant A mixture of water, a highly alkaline saturated solution of the builder salt, and undissolved particles of the water-soluble builder salt as the main component is formed. This viscous mixture is subjected to a high-speed disperser to grind undissolved particles, and then solid particles of a thickening agent are added to mechanically disintegrate the clay agglomerates.
Then the rest of the ingredients (eg other liquids or substances that are easily dissolved or dispersed in a liquid phase with a high electrolyte content).
Mix in. This mixture is then subjected to further high shear mechanical action to further break up the clay agglomerates. It has been found that this method does not require the clay to be pre-dispersed in an aqueous medium. Solid particles of clay disperse easily, even if the medium is strongly alkaline. Milling of undissolved builder salt particles is much more efficient and rapid in the substantial absence of clay.

In the method described in Examples 4-6, the builder salt constituting the main part of the undissolved particles is preferably added to an aqueous solution in which the other builder salt is already dissolved at a high concentration,
Such addition causes the builder salt to precipitate out of solution (eg, by the common ion effect) and recrystallize as small crystals.

Another important feature of the mixing method described in Examples 4-6 is that a batch of reproducible properties is obtained by using the entire "heel" of the previously formed batch as a component of the next batch. It can be repeated.

As indicated previously, the methods described in Examples 4-6 are not limited in their use to the production of potassium salt-containing compositions. Although this method has been found to be highly effective in the preparation of formulations where the clay is attapulgite, some or all of the clay is of the swollen type, for example bentonite (Gelwhite GP) or Smectir such as hectorite
e) can also be used in compositions that are clay.

Example 4 Ion-exchanged water 3 mixed with a small amount of pigment (0.028 parts of Graftor Green, which is an aqueous paste containing 28% of pigment)
2.0 parts, K ₂ CO ₃ (water solubility is 100 parts or more per 100 parts of water even at 0 ° C) 2.0 parts and granular sodium carbonate (water solubility is 100 ° C at 100 ° C water)
5.0 parts (about 45 parts per part) were completely dissolved. The temperature of the solution was about 32.2 ° C (90 ° F). Then 23.116 parts of powdered STPP containing about 0.5% water of hydration were added while the mixture was continuously run through a high speed disperser. The amount of STPP far exceeded the amount soluble in the water present. The water solubility of STPP is about 20 g per 100 ml of water at 25 ° C. The STPP in this example is a product of Olin Corp-, has a very fine particle size with a sodium sulfate content of about 2%, and is powdered anhydrous STPP produced by the known "wet process". It is a mixture with powdered STPP hexahydrate. When this STPP was added to the solution, it rapidly hydrated to form a hard crystalline mass containing STPP hexahydrate. (23 parts STPP incorporates about 7 parts water upon hexahydrate formation.) The mixture was initially a thin slurry of undissolved STPP in a supersaturated solution. The temperature rose due to the hydration reaction, peaking at about 60 ° C (140 ° F). In about 3-4 minutes the mixture became very viscous and its viscosity was about
It has risen to over 20.000 cps. (Brookfield RVT,
Approximately 40.000-50.000 using Spindle # 6 at 10 RPM at slurry temperature). During this process, it is believed that sodium carbonate precipitates out of solution phase (in the form of very fine crystals) as crystals due to the common ion effect (of sodium in STPP). When the mixture becomes viscous, the high speed disperser acts to grind particles (eg, TPP hydrate particles) into a fine particle size, which in part increases the power consumption of the disperser and the temperature. Further rise (eg 65.6 ℃
(150 ° F.), which increases the solubility of the builder salt and recrystallises in finely divided form on cooling). The milling was continued for about 5 minutes after the initial slurry concentration. It is considered that during this crushing, the mass of material became invisible to the eyes and almost all undissolved particles had a particle size of 40 microns or less. Next, 9-367 parts of water was further added to reduce the viscosity to 10.000 cps or less (for example, measured near 5000 cps as described above), and then 3.3 parts of Attagel # 50 and 0.732 parts of white TiO ₂ (anatase). ) The pigment was added to a strongly alkaline mixture (pH is well above 9 eg 10.5) while the mixture was continuously placed under the action of a high speed disperser to break up most clay agglomerates. As a result, the thick mixture became uniform and smooth in appearance. Next, 2.70 parts of 50% NaOH aqueous solution and 0.16 of antifoaming agent (Kunapuzaku LPKN158)
Part, 47.5% sodium silicate aqueous solution (Na ₂ O: SiO ₂ is 1: 2.4)
10.53 parts, 12 parts of 12% aqueous sodium hypochlorite solution and bleach-resistant anionic surfactant (Dowfax 3B
0.8 parts of a 45% aqueous solution of 2) was added. These additions can be carried out under any desired mixing conditions such as simple stirring. The mixture is then Tekmar "dispax" (although it is convenient to continue the high shear dispersing action).
Grinding action is added to the mixture such as by passing it through an in-line mill such as a "reactor" (operating at a maximum speed of 22 m / sec). The "Dispats Reactor" imparts a high shear rate to the mixture in a relatively short time. (For example, the "residence time" in the mill is no more than 2 seconds.) The main effect is to further break up agglomerates of clay particles, which significantly increases the yield value, eg It is shown by increasing the yield value of the mixture by about 33%.

The resulting mixture is thixotropic. Regarding the particle size of the dispersed solid particles inside, it is considered that about 80% by weight or more is fine such that the particle size is 10 microns or less. The temperature of this mixture is near 120-130 ° F (48.9-54.4 ° C) (viscosity at this temperature is higher than that at 70 ° F (21.1 ° C)). The mixture is discharged from the mixing vessel. Approximately 10% of the mixture remains as a "heel" in the container (eg from the bottom valve if the bottom of the container is conical, or from the valve on the underside of a substantially flat bottom mixing container) . This flow characteristic makes it difficult to withdraw the entire composition from the container.

The entire procedure is then repeated many times in the same mixing vessel without removing the heel.

The high speed disperser comprises a circular horizontal plate with peripheral teeth extending alternately upwards and downwards, the disk having a peripheral speed (of the teeth).
22.9m / sec (75 feet / sec) or more (for example, 27.4m / sec,
It is mounted (on a shaft that extends vertically downward) so that it can rotate at a high speed (90 feet / second). For laboratory operations, the Cowles high-speed disperser is suitable; for large-scale operations, Myers
Model 800 series high speed disperser can be used. These high speed dispersers reduce particle size by impact milling on toothed plates and laminar shear stress on the mixture. In addition to the heat generated by dissolution, hydration, etc., this shearing action also generates heat in the hatch. At the resulting relatively high temperature, the components become more soluble and upon cooling, relatively fine crystals which do not settle rapidly are obtained. The high speed disperser induces "rolling" of the mixture. That is, the moving path of the mixture descends in the central part of the container and goes outward along the rotating plate,
It rises along the side wall of the container and faces inward at the top surface of the mixture. In the course of this transfer, the desired degassing occurs, ie air (which is always introduced during powder addition) will escape from the mixture as it passes through the inner legs of the circuit.

After treatment of the composition described above, crystal growth clearly occurs and a large number of large and relatively uniform size crystals are formed. That is, (shown in the photograph), that is, FIG. 4 shows the presence of crystals having a diameter on the order of 80 microns. These crystals appeared to contain polyphosphate but were not fully identified.

Example 5 STPP powder was manufactured by "dry method" Monsanto anhydrous ST
Anhydrous STPP whose PP is moistened to a water content of hydration of 0.5% (or somewhat higher, eg 1.5%)
Example 4 was repeated except that This STPP
Was also used in Example 3.

Example 6 A first water proportion of 28.0 parts, a second water proportion of 13.637 parts, of sodium polyacrylate (Acrycol LMW-45N, molecular weight about 4500) prior to addition of attapulgite viscosity. Example 4 was repeated except that 1.11 parts of a 45% aqueous solution was added. In this example, the amount of K ₂ CO ₃ was 3 parts and the amount of Na ₂ CO ₃ was 4 parts.

The products of Examples 4-6 had the following properties.

“Centrifugation” is the centrifugation performed at 275 G as in Example 3 above, and the volume of the transparent liquid phase was measured with respect to the total volume.

"Thixotropic index" is the viscosity at 30 rpm / viscosity at 3 rpm as measured at room temperature using a Brutsk Field HATD viscometer # 4 spindle as described in the above-referenced US patent application Serial No. 497,615. Is a ratio.

In Example 6, a soluble chlorine bleach resistant polymer was present. It has been found that the presence of this polymer improves the resistance of the product to separation on standing or on centrifugation, yet does not correspondingly increase the product viscosity significantly. This polymer is present in a very concentrated (saturated) electrolyte solution state. It has also been found that the presence of this polymer provides better protection of the glaze layer of tableware (fine-grained porcelain). These effects were observed with polyacrylates, which are quite compatible with the chlorine bleach of the system as well as the clay, ie the active chlorine content is kept constant like clay. Was found. Polymers having various molecular weights can be used, for example, those having a molecular weight of less than 10.000 or those having a molecular weight of 100.000 or more may be used. The ratio of the polymer is in the range of 0.01 to 3%, and it is more suitable to decrease the ratio as the molecular weight becomes higher. (For example, molecular weight 30
0.06% for 0.000 polymer) Other bleach-resistant polymers can also be used.

In this application, all percentages are by weight unless otherwise indicated.
In the examples, atmospheric pressure was used unless otherwise specified.

It will be appreciated that the foregoing detailed description is merely for purposes of illustration and that variations can be made without departing from the spirit of the invention.

[Brief description of drawings]

1 to 3 are graphs of the products of the three examples measured with a Haake viscometer, and the peak Y shows a yield value. FIG. 4 is a micrograph of the crystal structure of the composition of Example 4.

Claims (6)

[Claims] 1. A slurry of solid particles of an alkaline water-soluble builder salt is formed in an aqueous liquid saturated with an alkaline water-soluble builder salt, wherein the proportion of such solid particles is such that the viscosity of the slurry is about 20,000 to 60,000 centipoise high, wet milling the solid particles with the viscous slurry in a high speed disperser operating at a tip speed of at least about 22.9 m / sec (75 ft / sec). ,
Then water is added to reduce the viscosity of the slurry, and powdered clay is added, and in the presence of solid particles of the soluble builder salt, the agglomerates of the clay in the slurry are subjected to mechanical action. A method for producing a thixotropic detergent slurry, which comprises crushing by grinding. 2. The method of claim 1 wherein the particles are at least predominantly sodium tripolyphosphate and the clay is attapulgite clay. 3. The method according to claim 1, wherein a water-soluble anionic surfactant is subsequently added to the obtained mixture. 4. By adding substantially anhydrous sodium tripolyphosphate to an aqueous solution of an alkali metal carbonate,
The method of claim 1, wherein the viscous slurry is formed. 5. The method according to claim 4, wherein the concentration of the alkali metal carbonate in the solution is so large that sodium carbonate is crystallized from the solution by the added sodium tripolyphosphate. 6. A method according to claim 2 wherein the proportion of clay is about 1-5%.