I
GRANULAR MULTI-SURFACE CLEANER WITH BLEACH
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of granular multi-surface cleaners. In more detail, the compositions of this invention contain a high level of dry chlorine bleach which provides the benefits of deodorization and sanitization, as well as high detergent levels for excellent cleaning. At the same time, the product is very resistant to the release of excessive levels of heat, gas, and foam that may result from accidental contact with water in a product not made according to the invention.
2. Description of the Related Art
U.S. Patent 3,361,675 to Fuchs et al., issued January 2, 1968, discloses dry-mixed, built detergent compositions said to be resistant to formation of objectionable fines. For example, the patent describes a hard surface cleaner containing sodium carbonate, and spray-dried beads of alkyl benzene sulfonate and sodium sulfate, along with other ingredients. The patent also discloses a machine dishwashing detergent containing granular sodium tripolyphosphate, sodium carbonate, and sodium dichloro- cyanurate. Since the ingredients of the detergent compositions are dry mixed, the detergents will have a high bulk density.
U.S. Patent 3,278,443 to Bright et al . , issued October 11. 1966, discloses a scouring powder made of sodium dodecyl benzene sulfonate, sodium tripolyphosphate, sodium carbonate, trichlorocyanuric acid, and a stabilizing compound to prevent loss of active chlorine over time. The ingredients of the scouring powders are dry mixed, and as a result will be high in density.
U.S. Patent 3,789,000 to Berkowitz, issued January 29, 1974, discloses an automatic dishwasher composition containing sodium carbonate, a surfactant, sodium tripolyphosphate, and sodium dichloroisocyanurate dihydrate. The patent discloses dry mixing the product in a commercial mixer.
U.S. Patent 3,360,469 to Fuchs, issued December 26, 1967, discloses granular detergent compositions containing sodium tripolyphosphate. The granules are compacted to a high density in order to overcome a problem with dissolving the granules in water. U.S. Patent 3,338,836 to Krusius et al., issued August 29, 1967, discloses cleansing tablets containing sodium chloride, polyphosphate, detergents, and a chlorocyanuric compound. The tablet is characterized as being physically strong and capable of fast dissolution in water. U.S. Patent 3,293,188 to Brown et al., issued December 20, 1966, discloses a powdered bleaching, sterilizing, and disinfect¬ ing composition that contains dichlorocyanurate, sodium tripolyphosphate, and sodium sulfate. The composition is mixed with a special carrier agent to provide stability for the bleach. U.S. Patent 3,265,624 to Inamorato, issued August 9, 1966, discloses anionic detergent compositions containing chlorine bleach. The compositions also contain a specific kind of quaternary ammonium salt.
U.S. Patent 3,256,199 to Sy es, issued June 14, 1966, dis- closes a household laundry bleach containing a chloroisocyanurate compound, sodium tripolyphosphate, sodium sulfate, and sodium dodecylbenzene sulfonate.
U.S. Patent 3,213,029 to Muchow et al., issued October 19. 1965, discloses granular compositions having a bulk density of from 0.85 to 1.0 g/cc, that contain a trichlorocyanuric acid or dichlorocyanuric acid, and that can also contain surfactants, builders and other materials.
U.S. Patent 2,913,460 to Brown et al . , issued November 17. 1959, discloses a powdered bleaching, sterilizing and disinfect.nq composition that contains dichlorocyanuric acid. The composition
can also contain sodium tripolyphosphate, sodium sulfate and other ingredients. It is stated that the density and particle size of the powder is regulated during the spray-drying operation. However, it is not suggested that a low density product is impor- tant for the stability of the bleach.
U.S. Patent 2,897,154 to Low, issued July 28, 1959, discloses dry bleaching and disinfecting compositions which contain trichlorocyanuric acid as a bleaching agent. Silver nitrate, silver phosphate, silver oxide, silver carbonate, or mercuric nitrate are added to stabilize the bleach in the cleaning composi¬ tion.
U.S. Patent 2,607,738 to Hardy, issued August 19, 1952, and Reissue Patent 24,412 to Hardy, reissued December 31, 1957, discloses bleaching, sterilizing, disinfectant and detergent compositions containing trichlorocyanuric acid, tetrasodium pyrophosphate, sodium silicate, sodium sesquicarbonate, and sodium dodecyl benzene sulfonate.
None of these prior patents suggests a good way of making a dry granular detergent that contains high levels of chlorine bleach, surfactant and builder, and which is at the same time stable upon contact with water so that there is an avoidance of accidental release of excessive levels of heat, gas and foam.
SUMMARY OF THE INVENTION The invention is a granular multi-surface cleaner comprising detergent granules admixed with dry bleach;
(a) wherein the multi-surface cleaner has a particle size between about 50 microns and about 2000 microns in diameter, a bulk density between about 250 grams/liter and about 600 grams/liter, and a pH above 7; (b) wherein the detergent granules comprise:
(i) from about 11% to about 35% surfactants by weight of the multi-surface cleaner, wherein nonionic surfactants comprise not more than about 2% by weight of the cleaner;
(ii) from about 10% to about 80% combined builder plus alkalinity source by weight of the multi-surface cleaner, wherein the alkalinity source is selected from the group of compounds consisting of hydroxides, amines, and mixtures thereof, and wherein the cleaner comprises not more than about 5% by weight alkalinity source; and (iii) the remaining part fillers, minor ingredients, moisture, and mixtures thereof; (c) wherein the bleach is a dry bleach selected from the group consisting of N-chloro compounds, and mixtures thereof, and wherein the multi-surface cleaner comprises from about 5% to about 30% bleach by weight of the cleaner. The cleaner of the invention incorporates high levels of chlorine bleach, surfactant and builder. At the same time, the product is stable against the hazards of accidental decomposition from contact with water.
DESCRIPTION OF THE PREFERRED EMBODIMENTS 1. Background A desirable cleaner would be effective at cutting grease and dirt on floors, and at the same time effective in sanitizing and deodorizing. To obtain these benefits, a suitable cleaner should have levels of surfactant, builder, and bleach. Liquid cleaners have the disadvantage in that levels of not more than about 0.5% surfactant can be incorporated in the presence of chlorine bleach, because the cleaner will quickly lose available chlorine activity due to instability of the bleach in the presence of water and higher levels of surfactant. Available chlorine levels above 5.5% are not recommended due to loss of available chlorine activity after only a few weeks of storage. Accordingly, in the present invention it was determined to attempt to make a dry granular cleaner that could incorporate higher levels of bleach, surfactant and builder.
It was discovered that mechanically dry mixed versions of detergent plus chlorine bleach with densities in the range of 740
to 855 grams/liter generated temperatures in the range of 200βF (93*C) when wetted with water. This resulted in the water boiling, foaming of the mixture out of its container and evolution of gases containing chlorinated compounds. The gases were noxious and could possibly be harmful to restaurant patrons and employees in an enclosed space.
On the other hand, when the desired finished product was formulated with spray-dried detergent granules in combination with admixed dry chlorine bleach and sodium carbonate with a finished product density of approximately 350 grams/liter and exposed to the same volume of water, the temperature did not rise above 150βF (66"C) and very little foaming or evolution of gases containing chlorinated compounds was observed.
In view of this discovery, it was concluded that a low density product must be used in order to incorporate the combination of desirably high levels of chlorine bleach, surfactant and builder into a dry cleaner, while avoiding the danger of release of excessive levels of heat, gas and foam that could result in a "restaurant clearing" incident of patrons and employees and loss of available chlorine activity.
A multi-surface cleaner having a specific low density according to the present invention is stable against this accidental decomposition. Moreover, the product of the invention does not require inclusion of any special ingredient to protect against thermal decomposition of the formula. 2. The Multi-Surface Cleaner
As discussed above, the present invention allows the combining of very high levels of surfactant, builder, alkalinity and chlorine bleach into a stable granular floor cleaner, and avoids the liberation of excessive amounts of heat, foam and gases when the storage container of product is brought in contact with water simulating a misuse splashing situation that can occur in the restaurant environment. The product is also stable upon storage, warehousing and transportation.
The granular multi-surface cleaner of this invention com¬ prises detergent granules admixed with dry bleach. The cleaner must h_ave a low bulk density, in the range between about 250 grams/liter and about 600 grams/liter, to effectively avoid the above-described problems. While not intending to be limited by theory, it is believed that by having a low density cleaner, the concentration of the surfactant and builder are kept low enough to avoid the problems caused by a denser product. Preferably, the cleaner has a density between about 300 grams/liter and about 500 grams/liter, and more preferably, between about 300 grams/liter and about 425 grams/liter.
The cleaner of the invention has a particle size range between about 50 and about 2000 microns in diameter, preferably between about 100 and about 1500 microns. The pH of the cleaner product must be above 7, preferably above about 9, and most preferably between about 9 and about 11, for the product to provide good cleaning properties. As with other cleaners and detergents, the present multi-surface cleaner functions optimally within this basic pH range to remove soils and stains. This alkaline pH can be derived from various ingredients of the cleaner composition (e.g., the alkalinity source, usually the surfactant and sometimes the builder provide alkalinity), and if needed, other ingredients such as pH-adjusting agents can also be added. In order to provide a low density cleaner product, and to avoid decomposition of the dry bleach, the detergent granules of the cleaner are made separately and then admixed with the bleach. This and related matters are discussed in more detail hereinbelow in the "Processing" section. Since the dry bleach typically has a fairly high density of about 900-1000 grams/liter, the detergent granules of the cleaner product usually must be low in density so that the overall product has a low density. (If a dry bleach is used that has a low density itself, the granules do not have to be quite as low density as otherwise.) The detergent granules preferably have a density between about 200 and about 575 grams/liter, more preferably between about 220 and about 500
grams/liter, and most preferably between about 240 and about 360 grams/liter.
3. Bleach The multi-surface cleaner of this invention comprises from about 5% to about 30% bleach by weight of the cleaner, preferably from about 7% to about 25%, and more preferably from about 8% to about 20%. The delivery of these high levels of bleach is an important benefit of the present invention. The bleaches that are useful in the invention are nitrogen-chlorine systems or
"chlorinated isocyanurates". These bleaching agents are disclosed in Kirk-Othmer, Encyclopedia of Chemical Technology. 3rd edition, Vol. 3, at page 942. As stated by Kirk-Othmer, nitrogen-chlorine or "N-chloro" systems are all compounds in which chlorine is chemically bonded with nitrogen, including chloraraines, chloramides, chlorimines, chlorimides, chlorosulfanamides, and chlorohydantoins such as l,3-dichloro-5,5-dimethylhydantoin. These compounds yield hypochlorous acid and/or hypochlorite anion. The preferred bleaching compounds for use in the present invention are the chlorinated isocyanurates, which are chlorimides. As discussed by Kirk-Othmer, they are prepared by chlorination of cyanuric acid under various reaction conditions to produce di- or trichloroisocyanuric acid or various alkali metal or alkaline earth metal dichloroisocyanurate salts. Several of these bleaching compounds are sold by 01in
Chemicals Research, 350 Knotter Dr., Cheshire, CT 06410. 01 in's "CDB Clearon" is a sodium dichloro(iso)cyanurate dihydrate. "CDB 63" is a sodium dichloro(iso)cyanurate. "CDB 90" is a trichloro(iso)cyanuric acid. 4. Surfactant
The detergent granules of the present multi-surface cleaner comprise from about 11% to about 35% surfactants, preferably from about 15% to about 30%, and more preferably from about 15% to about 25%, by weight of the cleaner. The surfactant can be any organic surfactant selected from the group consisting of anionic. nonionic, zwitterionic, a phlolytic and cationic surfactants, and
mixtures thereof. The detergent granules can contain any of the surfactants disclosed in U.S. Patent 4,379,080 to Murphy, issued April 5, 1983, at column 3, line 31 to column 5, line 62, the disclosure of which is incorporated by reference herein. Surfactants useful herein are also listed in U.S. Patent 3,644,961 to Norn's, issued May 23, 1972, and in U.S. Patent 3,919,678 to Laughlin et al., issued December 30, 1975, both incorporated herein by reference. Useful cationic surfactants also include those described in U.S. Patent 4,222,905 of Cockrell, issued September 16, 1980, and in U.S. Patent 4,239,659 to Murphy, issued December 16, 1980, both incorporated herein by reference.
The only limitation on the use of surfactants in this inven¬ tion is that nonionic surfactants must comprise not more than about 2% by weight of the multi-surface cleaner. It has been found that nonionic surfactants at levels of more" than about 2% are unstable in combination with the bleach used in the invention.
Particularly preferred surfactants herein include linear alkylbenzene sulfonates containing from about 11 to 14 carbon atoms in the alkyl group, especially sodium linear Cπ-13 alkylbenzene sulfonate; tallowalkyl sulfates; coconutalkyl glyceryl ether sulfonates; alkyl ether sulfates wherein the alkyl moiety contains from about 14 to 18 carbon atoms and wherein the average degree of ethoxylatioπ is from about 1 to 4; olefin or paraffin sulfonates containing from about 14 to 16 carbon atoms; alkyldimethyl amine oxides wherein the alkyl group contains from about 11 to 16 carbon atoms; alkyldimethylammonio propane sulfonates and alkyldimethylammonio hydroxy propane sulfonates wherein the alkyl group contains from about 14 to 18 carbon atoms: soaps of higher fatty acids containing from about 12 to 18 carbon atoms; and mixtures thereof. 5. Builder
The detergent granules of the present multi-surface cleaner also comprise from about 10% to about 80% combined builder plus alkalinity source (by weight of the multi-surface cleaner), preferably from about 25% to about 50%, and more preferably f/om
about 30% to about 45%. (That is, when the amount of the builder is added to the amount of the alkalinity source, the combined percentage is 10-80%.) The "alkalinity source" is defined hereinbelow. The builder can be any kind known to the art for use in cleaner or detergent compositions. Specifically, examples of suitable builders are disclosed in U.S. Patent 3,985,669 to Krummel et al., issued October 12, 1976, at column 12, line 62 to column 14, line 14, the disclosure of which is incorporated by reference herein. Specific examples of non-phosphorus, inorganic detergent builder ingredients include water-soluble inorganic carbonate and bicarbonate salts. The alkali metal, e.g. sodium and potassium, carbonates and bicarbonates are particularly useful herein, especially sodium carbonate. Examples of suitable phosphorous builder compounds are disclosed in U.S. Patent Nos. 3,159,981, 3,213,030, 3,422,021, 3,422,137, 3,400,176, and 3,400,148, which are incorporated herein by reference. Such builders can be, for example, water-soluble salts of phosphates, pyrophosphates, orthophosphates, polyphosphates, phosphonates, carbonates, polyhydroxysulfonates, polyacetates, carboxylates, polycarboxylates, and succinates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, pyrophosphates, phosphates, and hexametaphosphates.
The "alkalinity source", as used herein, is a water-soluble, basic material selected from the group of compounds consisting of hydroxides, amines, and mixtures thereof. The hydroxides are alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, or ammonium hydroxide. The "amines" are the mono-, di- and tri-ethanolamines. The amount of "alkalinity source", defined herein as the hydroxides and amines, is limited to not more than about 5% by weight of the multi-surface cleaner. (The amount of various other types of compounds that provide alkalinity to the cleaner is not limited, as long as the resulting cleaner product has an acceptable pH.)
6. Other Ingredients
Other ingredients commonly used in cleaner or detergent compositions can be included in the detergent granules of the multi-surface cleaner of this invention. These include fillers (e.g., sodium sulfate), color speckles, suds boosters or suds suppressors, anti-tarnish and anti-corrosion agents, soil suspending agents, soil release agents, dyes, optical brighteners, germicides, anti-caking agents, hydrotropes, enzymes, enzy e- stabilizing agents, and perfumes.
Besides fillers and the other minor ingredients discussed hereinabove, moisture will make up the remaining part of the detergent granules. By weight of the multi-surface cleaner, the detergent granules preferably comprise about 1-20% moisture, more preferably about 1-12%, about 5-15% filler, and about 0-10% other minor ingredients.
7. Processing
The granular multi-surface cleaner of the present invention is prepared by making low density detergent granules, and then mixing the detergent granules with dry bleach using a low work input mixing method to avoid densifying the product. The low density granules are generally prepared by drying an aqueous slurry of the ingredients which make up the granules. The drying operation can be accomplished by any convenient means, for example, by using spray-drying towers, both counter-current and co-current, fluid beds, rotary dryers, flash-drying equipment, or industrial microwave or oven drying equipment. What is important is that the resulting product granules have the low bulk density required for the present invention. Persons skilled in the art will understand how to adjust a given type of drying equipment to make low density granules. For example, adjustments to the types and arrangements of spraying nozzles in a spray-drying tower can be made depending on the rate of product through the tower and the product compositions. A process in which the ingredients are simply mechanically admixed (instead of spray-drying or the like) would not be
suitable for the present invention, because the density of the detergent granules and the resulting cleaner product would be too high.-
As an alternative to spray drying, low density granules can be produced by a method described in GB 1,404,317 (Bell). The ingredients are mixed with an excess of soda ash in the presence of sufficient water to initiate the neutralization reaction but not enough to wet the resultant product, which is in the form of a free-flowing powder. The process is carried out in an apparatus, for example a ribbon blender, planetary mixer of air transfer mixer, in which the reactants are "tossed and fluffed", and carbon dioxide liberated during the neutralization is entrapped in the product particles. Light, porous particles are produced comparable to those obtained by spray drying. It is important that the dry chlorine bleach be admixed separately after the detergent granule ingredients have been spray-dried or otherwise processed to make low density granules. Addition before the spray-drying could cause the bleach to become unstable and decompose. When the bleach and any other remaining ingredients are admixed with the low density detergent granules, it is important that this mixing be conducted with a low work input. Too much work input could cause the resulting multi-purpose cleaner product to have a density that is tod high. Suitable low work input mixing equipment includes belt mixers, rotating drum mixers, and Speed Flow mixers.
A small proportion of the ingredients making up the detergent granules can be left out of the granules and admixed separately with the granules along with the dry bleach, provided the overall product density is kept low enough to be within the present claims. If too much of the composition is admixed separately along with the bleach, the bulk density of the resulting product will be too high. As shown in the Example below, in the preferred embodiment of the present invention the sodium carbonate of the formula is separately admixed along with the dry bleach.
EXAMPLE A granular multi-surface cleaner according to the present invention is made as follows.
Product Formulation NaCn.8--AS (surfactant) Sodium sulfate (filler/reaction by-product)
Sodium silicate, 1.6R (processing aid)
Sodium tripolyphosphate (builder)
Polyacrylate solids (processing aid)
Sodium carbonate (builder) NaDCC-2H2θ (sodium dichloroisocyanurate dihydrate, bleach source)
Phthalocyanine green (green dye)
Moisture
Misc.
Mineral oil (dedusting agent)
Process First, a surfactant paste is made as follows. Continuous sulfonation of linear alkyl benzene with H SO4 and dissolved SO3 yields linear alkyl benzene sulfonic acid. Sodium hydroxide solution is added and neutralizes the sulfonic acid to form sodium linear alkyl benzene sulfonate (NaLAS) plus sodium sulfate and water.
In a large mixing apparatus, the surfactant paste is mixed with extra sodium sulfate and water, and with the sodium silicate. sodium tripolyphosphate and polyacrylate solids. During the mixing operation, this mixture of ingredients has a moisture content between 32% and 45%, and the temperature of the mixture ■ > between 140'F (60βC) and 160'F (71"C) . The ingredients are mixed
for a time between 5 minutes and 30 minutes, typically about 20 minutes.
The mixture of ingredients next flows into a drop tank, then flows through a low pressure pump and a high pressure pump to a countercurrent spraying tower. The spraying tower is 21 feet in diameter and about 60-70 feet high. The tower has top, middle and bottom arms that enter the tower chamber for injection of the ingredient mixture into the chamber, the top arm being about 56 feet high, the middle arm being about 32 feet high, and the bottom arm being about 16 feet high. The top and middle arms each have two injection nozzles, while the bottom arm has seven nozzles. No. 10 type nozzles are used, having 10/64-inch diameter openings. Hot air at 500βF-750βF (260'C-400βC) enters through an inlet at the bottom of the tower, and the air moves up the tower chamber and exits through an outlet at the top of the tower. The outlet air temperature is about 200°F (93*C). The pressure in the injection nozzles is 800-1100 psig, and as the ingredient mixture is sprayed through the nozzles into the tower chamber it becomes atomized into tiny droplets, which upon drying form aerated, light and porous granules. The hot granules (temperature about
100#F-140*F, 38#C-60'C) fall to the bottom of the tower, and are collected. The,detergent granules after spray drying have a bulk density of about 300 grams/liter.
The detergent granules are next transported up an air lift (to cool and transport), and through a Rotex particle sizer which removes particles larger than 2000 microns. The granules are then dropped onto a conveyor belt. At the same time, the sodium carbonate and bleach of the product are separately dropped onto the belt. The granules, sodium carbonate and bleach are admixed together by dropping them from belt to belt. (Alternatively, a rotating drum or other continuous mixer could be used.) This mixing involves low work input, because too much working would produce a too dense product. During the mixing operation the mixture is sprayed with mineral oil (to reduce dustiness of the
product) and green dye. The product is then transported to storage before packaging.
The multi-surface cleaner product has a bulk density of about 350 grams/liter, an average particle size of about 500 microns and a particle size range between about 100 and about 1500 microns. The cleaner product has a pH of about 10.