WO2021240442A1

WO2021240442A1 - Solid state cleaning article

Info

Publication number: WO2021240442A1
Application number: PCT/IB2021/054659
Authority: WO
Inventors: Chunjie Zhang; Yifan Zhang; Zai-Ming Qiu; Kyle C. Bryson; Thomas A. PORTELLI; Rachel ULRICH; Siwei LENG; Eric J. OLSON; Narina Y. Stepanova
Original assignee: 3M Innovative Properties Company
Priority date: 2020-05-29
Filing date: 2021-05-27
Publication date: 2021-12-02

Abstract

The present invention is a cleaning composition including a gas generator having particle sizes of between about 44 and about 2000 µm, an acid having particle sizes of between about 44 and about 4000 µm, a chelating agent having a particle size of between about 74 and about 4000 µm, and a surfactant. The solid cleaning composition has a pH of between about 1 and about 5 when dissolved in water. A weight ratio of gas generator to acid is between about 1:0.6 to about 1:3 and a weight ratio of acid to chelating agent is between about 1:0.4 and about 1:3.

Description

SOLID STATE CLEANING ARTICLE

Field of the Invention

The present invention relates generally to the field of cleaning compositions. In particular, the present invention is a cleaning composition for toilets

Background

Cleaning toilets is an undesirable but necessary task. Current methods of cleaning toilets commonly involve applying a cleaning agent within a toilet bowl and then scrubbing the toilet bowl with a handheld tool. The handheld tool generally includes bristles or a cleaning head that can be used to scour the inner surface of the toilet bowl, removing debris and stains. Due to the need to manually scrub the toilet bowl, the person cleaning the toilet must be in close proximity to the toilet, a condition which most people find unappealing.

In an attempt to create more distance from the toilet while cleaning it, various products have been developed that can be dropped into a toilet bowl to clean the debris and stains without the need for manually scrubbing the toilet bowl. However, most of these products include bleach or other harsh chemicals with their unpleasant, harsh odor and problematic environmental profile, to kill microbial soils. Other products do not include bleach, but do not clean the toilet bowl as thoroughly.

Summary

In one embodiment, the present invention is a cleaning composition including a gas generator having particle sizes of between about 44 and about 2000 pm, an acid having particle sizes of between about 44 and about 4000 pm, a chelating agent having a particle size of between about 74 and about 4000 pm, and a surfactant. The solid cleaning composition has a pH of between about 0 and about 5 when dissolved in water. A weight ratio of gas generator to acid is between about 1:0.6 to about 1:3 and a weight ratio of acid to chelating agent is between about 1:0.4 and about 1:3. Detailed Description

The present invention is a solid-state cleaning composition that provides effervescence, foaming, acidity and oxidizing ability after being dissolved in water. This cleaning composition has good stability at both room temperature and elevated temperatures. In one embodiment, the cleaning composition can be used along with other materials, e.g. surfactants and abrasives, to make a cleaning product. Compared to bicarbonate-based effervescent compositions, the cleaning composition of the present invention shows good stability when aged at elevated temperatures, indicating good stability and shelf life under ambient conditions. Thus, effervescence and foaming are not compromised compared to bicarbonate -based compositions. In addition, the cleaning composition of the present invention is environmentally friendly, being benign to humans and the environment. The cleaning composition is fully dissolvable in water and leaves no residue after cleaning. In one embodiment, the cleaning composition is used to clean toilet bowls.

The cleaning composition of the present invention provides effervescence, acidity, and oxidizing ability and can be used to clean and/or remove stains such as hard water stains. It is based on benign and environment-friendly chemistry and is compatible with many other materials such as surfactants, fragrance, abrasives, minerals, and colorants, to allow the creation of a wide spectrum of cleaning products. The key characteristics of this composition can be tuned to specifically allow enhanced oxidizing power, acidity or effervescence as needed by product development needs.

The cleaning composition generally includes a gas generator, an acid, a chelating agent, and a surfactant. In one embodiment, the cleaning composition includes between about 15 and about 30 wt% gas generator, between about 20 and about 60 wt% acid, between about 25 and about 50 wt% chelating agent, and up to about 5% surfactant. Particularly, the cleaning composition includes between about 20 and about 30 wt% gas generator, between about 20 and about 45 wt% acid, between about 35 and about 45 wt% chelating agent, and up to about 4 wt% surfactant.

The gas generator functions as an effervescent agent to create foam/bubbles. By producing foam and/or bubbles, the cleaning composition is capable of reaching additional surface area. Examples of suitable gas generators include, but are not limited to: carbon dioxide generators and oxygen generators. Examples of suitable carbon dioxide generators include, but are not limited to: bicarbonate salts of Group I metals, of Group II metals and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals; carbonate salts of Group I metals, of Group II metals, and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals; and percarbonate salts of Group I metals, of Group II metals, and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals. Examples of particularly suitable carbon dioxide generators include, but are not limited to: sodium carbonate and sodium bicarbonate.

Examples of suitable oxygen generators include, but are not limited to: hydrogen peroxide; peracetic acid generated from sodium percarbonate/TAED (tetraacetylethylenediamine); percarbonate salts of Group I metals, of Group II metals and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals; chlorate and perchlorate salts of Group I metals, of Group II metals and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals; superoxide salts of Group I metals, of Group II metals and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals; and peroxide salts of Group I metals, of Group II metals and of other cations, including ammonium, alkyl (mono-, di-, or tri-) ammonium, or those of transition metals.

The particle size of the gas generator is critical for both product performance and stability. Generally, small particle sizes dissolve quickly in water, foams quickly, and shows improved overall cleaning performance. However, due to its small size, smaller particles tend to be less stable under ambient conditions and at high temperatures. Compositions including larger particle sizes tend to show improved stability, but with reduced foaming and product performances. As such, an optimal particle size range is needed to achieve desired shelf life and product performance. In one embodiment, the gas generator has a particle size of between about 44 and about 2000 pm and particularly between about 74 and about 1000 pm.

The acid functions as both an effervescent agent and a cleaning agent. Examples of suitable acids include, but are not limited to: sodium bisulfate, sulfamic acid, benzoic acid, and succinic acid. In one embodiment, the gas generator has a particle size of between about 44 and about 42000 pm and particularly between about 500 and about 1500 pm. The chelating agent primarily functions as complex forming agents with metal ions dissolved in water. It also promotes cleaning as well as foaming. Examples of suitable chelating agents include, but are not limited to: citric acid and its sodium salts, ethylenediaminetetraacetic acid (EDTA) and its sodium salts, ethylene glycol tetraacetic acid (EGTA) and its sodium salts, and maleic acid and its sodium salts.

The particle size of the chelating agent is critical for both product performance and stability. Generally, small particle sizes dissolve quickly in water, foams quickly, and shows improved overall cleaning performance. However, due to its small size, smaller particles tend to be less stable under ambient conditions and at high temperatures. Compositions including larger particle sizes tend to show improved stability, but with reduced foaming and product performances. As such, an optimal particle size range is needed to achieve desired shelf life and product performance. In one embodiment, the chelating agent has a particle size of between about 74 and about 4000 pm and particularly between about 250 and about 2000 pm.

The surfactant is used as a cleaning and foaming agent. Examples of suitable surfactants include, but are not limited to: anionic surfactants, nonionic surfactants, cationic surfactants, zwitteronic surfactants, amphoteric surfactants, oligomeric and polymeric surfactants. Examples of suitable anionic surfactants include, but are not limited to: alkyl and alkyl ether sulfates, sulfated monoglycerides, sulfonated olefins, alkyl aryl sulfonates, primary or secondary alkane sulfonates, alkyl sulfosuccinates, acid taurates, alkyl sulfoacetates, acid isethionates, alkyl glycerylether sulfonate, sulfonated methyl esters, sulfonated fatty acids, alkyl phosphates, acyl glutamates, acyl sarcosinates, alkyl lactylates, anionic fluorosurfactants, sodium lauroyl glutamate, and combinations thereof. Additional suitable anionic surfactants include those disclosed in U.S. Patent Application No. 61/120,765 and those surfactants disclosed in McCutcheon’s Detergents and Emulsifiers, North American Edition (1992), Allured Publishing Corp. Examples of suitable nonionic surfactants include, but are not limited to: polyoxyethylenated alkyl phenols, polyoxyethylenated alcohols, polyoxyethylenated polyoxypropylene glycols, glyceryl esters of alkanoic acids, polyglyceryl esters of alkanoic acids, propylene glycol esters of alkanoic acids, sorbitol esters of alkanoic acids, polyoxyethylenated sorbitor esters of alkanoic acids, polyoxyethylene glycol esters of alkanoic acids, polyoxyethylenated alkanoic acids, alkanolamides, N-alkylpyrrolidones, alkyl glycosides, alkyl polyglucosides, alkylamine oxides, and polyoxyethylenated silicones. Examples of suitable cationic surfactants include, but are not limited to, those selected from the “quaternary ammonium” class of materials including but not limited to; cetyltrimethylammonium chloride, behenyltrimethylammonium chloride, stearyltrimethylammonium chloride, cetylpyridinium chloride, octadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octyldimethylbenzylammonium chloride, decyldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, didodecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, distearyldimethylammonium chloride, tallowtrimethylammonium chloride, cocotrimethylammonium chloride, dipalmitoylethyldimethylammonium chloride, PEG-2 oleylammonium chloride, and salts of these, where the chloride is replaced by halogen, (e.g., bromide), acetate, citrate, lactate, glycolate, phosphate nitrate, sulphate, or alkylsulphate. Examples of suitable zwitteronic and amphoteric surfactants include, but are not limited to: amine oxides, betaines (carboxylic acid/quatemary ammonium or carboxylic acid/phosphonium), sulfobetaines, or carboxybetaines, sultaines (sulfonic acid/quatemary ammonium or sulfonic acid/phosphonium), amino acid derivatives, imidizoline derivatives, lecithins, and phospholipids. Examples of suitable polymeric surfactants include, but are not limited to: block copolymers of ethylene oxide and fatty alkyl residues, block copolymers of ethylene oxide and propylene oxide, hydrophobically modified polyacrylates, hydrophobically modified celluloses, silicone polyethers, silicone copolyol esters, diquatemary polydimethylsiloxanes, and co-modified amino/polyether silicones.

The ratio of gas generator to acid enables an optimal combination of the amount of gas generated, pH of the solution, and cleaning performance. If there is a minimal amount of gas generator (low gas generator to acid ratio), not enough gas is generated, leading to minimal foaming height. If the amount of gas generator is present in an exceedingly large amount (high gas generator to acid ratio), the pH of the resulting solution is basic, compromising cleaning performance. In one embodiment, the solid cleaning composition has a weight ratio of gas generator to acid of between about 1:0.6 to about 1:3, particularly between about 1:0.6 and about 1:1, and more particularly between about 1:0.9 and about 1: 1. The ratio of acid to chelating agent can provide an optimal combination of foaming speed, solution acidity, and cleaning performance. If there is a minimal amount of acid present (low acid to chelating agent ratio), foaming speed and solution acidity is reduced. If there is a minimal amount of chelating agent present (high acid to chelating agent ratio), removal of hard water stains is reduced as well as foaming height. In one embodiment, the solid cleaning composition has a weight ratio of acid to chelating agent of between about 1:0.4 and about 1:3, particularly between about 1:0.4 and about 1:1.8, and more particularly between about 1 : 1 and about 1:1.8.

The cleaning composition may optionally include an oxidizer to oxidize organic stains and to remove bacteria. Examples of suitable oxidizers include, but are not limited to: sodium persulfate and ammonium persulfate. In one embodiment, when the cleaning composition includes oxidizer, the cleaning composition includes up to about 15 wt% oxidizer, and particularly up to about 5 wt% oxidizer.

The cleaning composition may optionally include a biocide to remove bacteria. Examples of suitable biocides include, but are not limited to: benzalkonium chloride, sodium dichloroisocyanurate, benzisothiazolinone and chlorhexidine. In one embodiment, when the cleaning composition includes biocide, the cleaning composition includes up to about 5 wt% biocide, and particularly up to about 2 wt% biocide.

Other additives can be included in the cleaning composition to perform various functions. Examples include, but are not limited to: anti-caking agents, dispersants, fdlers/tougheners, binder softeners, abrasive particles, desiccants, cleaning agents, coupling agents, photoinitiators, thermal initiators, viscosity modifiers, adhesion promoters, grinding aids, wetting agents, dispersing agents, light stabilizers, antioxidants, anti-foam agents, coloring agents, dyes, pigments, and fragrances.

An acidic pH is favorable to cleaning surfaces, such as a toilet bowl, which are etched by protons in aqueous solution. In addition, hard water stains and lime scales can be dissolved under acidic conditions. A basic pH is favorable to forming hard water stains and deposits of organic matters on toilet bowl. Thus, it is desirable for the cleaning composition to have an acidic pH. In one embodiment, the cleaning composition has a pH of between about 0 and about 6 and particularly between about 1 and about 5 when dissolved in water. The cleaning composition of the present invention can take on any form in which it is deliverable to the area to be cleaned. In one embodiment, the cleaning composition is in the form of a tablet or pod. In one embodiment, the pod is formed of a water-soluble polymer fdm. For example, the pod may be formed of polyvinyl alcohol (PVA). This allows for the cleaning composition to be, for example, dropped into a toilet bowl. However, the cleaning composition may take any form, such as solid, liquid, or a combination of both, without departing from the intended scope of the present invention.

The cleaning composition can effectively remove various debris and stains, such as hard water stains and lime scale. In practice, the cleaning composition must come into contact with a sufficient amount of water, polar solvents, or a mixture of water and polar solvents to begin the reactions needed to clean the intended surface. Once the cleaning composition is exposed to water, the cleaning composition will begin to dissolve and foam. Water serves as a media for reactions to take place. The acid and gas generator react to release carbon dioxide which rises to the surface through aqueous solution of surfactants, creating bubbles in solution and forming a foam layer on surface. The foam and the aqueous solution underneath contain acid, chelating agent, and oxidizer. The foaming allows the cleaning agent to contact hard to reach surfaces, such as the underside of the inner surface of a toilet bowl. In one embodiment, a sufficient amount of foam is produced to have a foam height of at least about 0.5 cm, at least about 0.75 cm, at least about 1 cm, at least about 1.25 cm, at least about 1.5 cm, at least about 1.75 cm, at least about 2 cm, at least about 3 cm, at least about 4 cm, and least about 5 cm.

In one embodiment, when the cleaning composition is exposed to a surface for at least about 10-12 minutes, the cleaning composition can remove at least about 25%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95% of hard water stains. In one embodiment, when the cleaning composition is exposed to a surface for at least about 10-12 minutes, the cleaning composition can remove at least about 25%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95% of lime scale.

To make the cleaning composition of the present invention, the components are mixed together. If there is a fragrance, or any other liquid component, it is first mixed with any surfactants to form a pre-mixture, after which the pre-mixture is mixed with the mixture of remaining components. In one embodiment, the resulting cleaning composition is compressed to form a tablet. In one embodiment, the cleaning composition is wrapped by a water-soluble polymer film to form a pod.

Examples The present invention is more particularly described in the following examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to those skilled in the art. Unless otherwise noted, all parts, percentages, and ratios reported in the following examples are on a weight basis. MATERIALS

Table 1.

Test Method 1: Hard Water Stain Removal

Hard Water Stain Preparation

Part A solution was prepared as follows: about 9.9 g of calcium chloride dihydrate and 6.8 g of magnesium chloride hexahydrate were added into 250 g water. Part B solution was prepared as follows: about 7.1 g of sodium carbonate and 4.7 g of sodium sulfate were added into 250 g water. Hard water stains were then created on the surfaces of a black ceramic tile (2in x 2in, purchased from Home Depot). The black tile was put in a 100.5 °C (212 °F) oven and 4 droplets of Part A solution were deposited on the tile using a plastic disposable pipette. Each droplet was about 0.04 g. 6 droplets of Part B solution were then quickly added to the Part A solution droplets on the tile, and white precipitates were formed immediately. The mixture was then aged in the 100.5 °C (212 °F) oven for 4 hours and cooled at room temperature before testing.

Test Procedure

About 1000 mL of regular tap water was added to a 4 liter beaker. Then a black ceramic tile with hard water stains was added into the water at a tilted angle. A 20 g sample of the solid cleaning composition to be tested was added into the water, was allowed to react for about 12 minutes, and the foaming height of the system was recorded. The black ceramic tile was then taken out of the testing solution and dried at room temperature. The pH of the final solution was also measured and recorded.

After the tile completely dried, the amount of hard water stains removed was determined visually using a scale of 0-5 according to Table 2. All samples were tested in triplicate.

Table 2.

Test Method 2: Limescale Removal

Sample Preparation

A polished marble mosaic tile (Carrara white, lin x lin x l/4in, purchased from Home Depot) was used for limescale removal testing because like limescale, marble is composed primarily of calcium carbonate. The marble tile was pre-cleaned first by dipping into ethanol solution for about 30 seconds, and then rinsed with running water for about 2 minutes. While being rinsed, any residual left on the tile was removed by a brush to make sure the tile was clean. The marble tile was then dried at about 105.5 °C (222 °F) oven for 1 hour and cooled to room temperature before testing. The tile was weighed individually using an analytical balance, and the weight of the tile was recorded.

Test Procedure

About 1000 mL of regular tap water was added to a 4 liter beaker. A test marble tile (weight recorded) was then completely immersed into the water. A 20 g sample of the solid cleaning composition was added into the water to create a test solution and after 12 minutes, the marble tile was taken out of the test solution. The tile was rinsed under running water and any adhering residues was brushed off, followed by drying at about 105.5 °C (222 °F) for 1 hour. After the tile cooled to room temperature, the treated tile was weighed using an analytical balance and the weight was recorded. The quantity of dissolved limescale (calcium carbonate) was determined by the difference of the tile weight before and after treatment. All samples were tested in triplicate.

Test Method 3: Foaming Height

About 100 g of water was added to a 500 mL graduated cylinder. About 4 g of solid cleaning composition was added directly into the cylinder and the foaming formed from the product was monitored. Within 3 minutes, the maximum foaming height was measured and recorded.

Test Method 4: Time-Kill Assay

An in vitro, time-kill assay was used to determine the effectiveness of the antimicrobial solutions. The microorganism tested in these experiments was E. coli ATCC 8789. Microorganisms (E. coli ATCC 8789) were grown on DIFCO Tryptic Soy Agar (VWR, Radnor, PA) overnight. After incubation, E. coli inoculum was prepared in Butterfield’s phosphate buffer (3M Company, St. Paul, MN) with a cell density of approximately 1.0 x 10⁸ CFU/mL.

An antimicrobial solution (test sample, 30 ml) was combined with inoculums (300 ul) and vortexed to achieve good mixing. At determined time points (5 min and 10 min), the solution was neutralized to stop antimicrobial activity by combining 1 ml of test solution (sample) with 19 ml of DIFCO DE (Dey-Engley) broth (Fisher Scientific, Waltham, MA). The neutralized sample was further serial diluted in Butterfield’s phosphate buffer (3M Company, St. Paul, MN) and plated onto 3M Aerobic PETRIFILM (3M Company, St. Paul, MN). After 24 hours of incubation, the PETRIFILM plates were counted and the number of surviving microorganisms expressed in colony forming units (CFU) estimated.

Test control was prepared by combining Butterfield’s phosphate buffer (3M Company, St. Paul, MN) with E. coli inoculum and carried out in the same manner as a test sample.

Log reduction was calculated by subtracting viable cell counts of the test sample from the test control at determined time points.

Comparative Example A (C.E.-A)

About 0.8 g of sodium persulfate, 1.3 g of sodium bisulfate, and 0.5 g of potassium carbonate were added to a 20 mL glass vial, followed by manual tumbling to form a powder mixture, shown in Table 3. The powder mixture was then added to about 40 mL of deionized water. The powder mixture effervesced immediately without creating foam on top of water. The pH was measured to be between 0 and 1 using a pH strip after effervescence stopped. Some solid residue was left in the bottom of the water. A QUANTOFIX peroxide test strip was used to measure the equivalent amount of hydrogen peroxide created in solution. The solution exceeded the 100 mg/L upper limit of the test strip. Table 3.

Comparative Example B (C.E.-B)

About 0.8 g of sodium persulfate, 1.3 g of sodium bisulfate and 0.3 g of sodium bicarbonate were added to a 20 mL glass vial, followed by manual tumbling to form a powder mixture, shown in Table 4. The powder mixture was then added to about 40 mL of deionized water. The powder mixture effervesced immediately without creating foam on top of water. The pH was measured to be 1 using a pH strip after effervescence stopped. No solid residue was observed in the bottom of water. A QUANTOFIX peroxide test strip was used to measure the equivalent amount of hydrogen peroxide created in solution. The solution exceeded the 100 mg/L upper limit of the test strip.

Table 4.

Comparative Example C (C.E.-C)

About 8.5 g of sodium persulfate, 35.0 g of glycolic acid, 15.0 g of sodium bicarbonate and 0.50 g of CAB-O-SIL M-5 were added to a glass vial, followed by manual tumbling to form a powder mixture, shown in Table 5. The powder mixture was not free floating and formed clumps. Pressure built up inside the vial immediately after mixing. After about 7 weeks, liquid formed on the bottom of the vial. Table 5.

Comparative Example D (C.E.-D)

About 1.6 g of sodium persulfate, 2.7 g of sodium bisulfate, 1.5 g of sodium bicarbonate and 0.05 g of CAB-O-SIL M-5 were added to a 20 mL glass vial, followed by manual tumbling to form a powder mixture, shown in Table 6. The powder mixture was free floating and remained free floating after 2 months of aging at room temperature. The powder mixture was added to 300 mL of deionized water. The powder mixture effervesced immediately without creating foam on top of the water. The pH was measured to be 3 using a pH strip after effervescence stopped. No solid residue was observed in the bottom of water. A QUANTOFIX peroxide test strip was used to measure the equivalent amount of hydrogen peroxide created in solution. The solution exceeded the 100 mg/L upper limit of the test strip.

Table 6.

Comparative Example E (C.E.-E)

About 0.85 g of sodium persulfate, 3.5 g of sodium bisulfate, 1.5 g of sodium bicarbonate and 0.05 g of CAB-O-SIL M-5 were added to a 20mL glass vial, followed by manual tumbling to form a powder mixture. The powder mixture was free floating and remined free floating after 2 months of aging at room temperature. The powder mixture was added to 300 mL of deionized water. The powder mixture effervesced immediately without creating foam on top of water. The pH was measured to be 1 using a pH strip after effervescence stopped. No solid residue was observed on the bottom of water. A QUANTOFIX peroxide test strip was used to measure the equivalent amount of hydrogen peroxide created in solution. The solution exceeded the 100 mg/L upper limit of the test strip.

About 18.5 g of the solid formula was mixed with 0.62 g of LANTHANOL LAL and 0.40 g STEPANOL WA-100 NF/USP (Table 7). The powder mixture was added to 1 L of tap water in a 4 L glass beaker. The maximum foam height was measured to be about 1.7 cm. When the powder mixture was sealed in a PVA bag and put into 1 L of tap water in a 4 L glass beaker, the bag sank to the bottom. Effervescence started when the PVA bag started to dissolve. The maximum foaming height was measured according to Test Method 3 and was about 2.5 cm.

Table 7.

Comparative Example F (C.E.-F) and Examples 1-6

About 8.3 g of sodium persulfate, 57.9 g of sodium bisulfate, 25.0 g of sodium bicarbonate, 0.8 g of CAB-O-SIL M-5, 2.0 g of SIPERNAT 50S, 2.0 g of cornstarch, 2.5 g of LANTHANOL LAL, and 1.5 g of STEPANOL WA-100 NF/USP were added to a glass jar, followed by manual tumbling, to form a powder mixture shown in Table 8. The powder mixture was free floating. About 5.9 g of the powder mixture was added to 300 mL of tap water. The powder mixture effervesced immediately, creating foam on top of water. The pH was measured to be 2 using a pH strip after effervescence stopped.

Table 8.

The powder mixture of Comparative Example F was dissolved at about 10 g per 500 mL ultrapure water (resistivity of 18.2 MQ m at 25°C) and allowed to stand for five minutes. This solution was then sampled by volumetric pipette and titrated for total oxidizing capacity. The sample was transferred into a 125 mL iodine flask by volumetric pipette. A magnetic stir bar, 50 mL deionized water, 6 drops concentrated sulfuric acid, and about 10.0 mL ferrous ammonium sulfate were added. The flask was stoppered tightly and allowed to react for a minimum of three minutes before titrating with about 0.10 N ceric sulfate in sulfuric acid titrant that had previously been standardized with AR grade sodium oxalate. The sample was titrated in triplicate and triplicate blanks were carried through. All titrations were carried out using a Metrohm automatic titrator and combination platinum -pH Titrode electrode.

The total oxidizing capacity is calculated as follows:

Where: V_Biank = average volume to endpoint of the blanks (mL) Vsampie= volume to endpoint of the sample replicate (mL) N = Normality of titrant (Eq/L)

Sample Volume = Volume of sample analyzed (mL)

The oxidizing capacity was 0.01434 ± 0.00009 mEq/mL with 3 measurements, which corresponds to 0.00717 mEq/mL (mole/L) persulfate.

Comparative Example E and Comparative Example F were tested for E. Coli reduction using Test Method 4 described above. About 0.6 g of each formulation was dissolved in about 30 mL of phosphate buffer and about 6 log of E. coli ATCC 8789 was added. The resulting solution was then vortexed. After 5 min or 10 min incubation at room temperature, the solution was plated on AC PETRIFILM. The AC PETRIFILM was incubated for 24 hours and colonies were counted. The reduction of E. Coli is summarized in Table 9. able 9.

Comparative Example F was used to make Examples 1-2 (shown in Table 10) by adding to it specified amounts of citric acid. Citric acid was first added to the Comparative Example F powder mixture. Examples 1-2 were made as powder mixtures, and then put into water for testing. 1 L of tap water was added to a 4 L beaker with a hard water-stained black ceramic tile and a pre-weighed marble tile. Comparative Example F and Examples 1 and 2 were added into the water to create a test solution and allowed to react without agitation for 12 minutes. The black ceramic tile and the marble tile were then removed, rinsed with running water, and dried. The marble tile was dried in a 100.5 °C (212 °F) oven for 1 hour and then cooled to room temperature before the weight was measured.

Table 10.

The weight of the marble tiles before and after testing is summarized in Table 11. Table 11.

The photos of the hard water stained tiles before and after testing are shown in FIG 1. Hard water stain removal was determined by visual observation. The hard water stain removal was determined as being about 50%, 70% and 90% for Comparative Example F and Examples 1 and 2, respectively.

Figure 1.

The Comparative Example F composition of Table 8 was used to make Examples 3-6 by adding specified amounts of sodium bisulfate and citric acid. The additional components were first added to powder mixture. The Examples 3-6 powder mixtures were then put into water for testing using Test Methods 1 and 2 described above. Table 12.

The amount of limescale removal (weight loss of marble tile before and after the test) was determined and is summarized in Table 13.

Table 13.

The photos of the hard water stained black ceramic tiles before and after being submerged in solutions of Examples 3-6 are shown in FIG. 2. Hard water stain removal was determined by visual observation and was determined as being about 80%, 70%, 95%, 60% for Examples 3-6, respectively.

Foaming height was tested for Examples 3-6 using Test Method 3 above. The maximum foaming height for each Example is summarized in Table 14. Table 14.

Comparative Example G (C.E.-G)

About 0.83 g of sodium persulfate, 5.79 g of sodium bisulfate, and 2.5 g of sodium bicarbonate were added to a glass vial, followed by manual tumbling to form a powder mixture, shown in Table 15. The resulting Comparative Example G was used for thermal gravimetric analysis (TGA) analysis along with Comparative Example F and sodium bicarbonate. TGA curves were summarized in FIG.3. High resolution TGA (TA Instruments Discovery TGA, a thermal gravimetric analyzer equipped with an IR furnace that covers a temperature range from ambient to 1200 °C) was used to analyze samples by ramping up temperature at 20 °C/min from room temperature to 500 °C as shown in Figure 3(a). Isothermal TGA was performed by holding temperature at 65 °C for 1 hour as shown in Figure 3(b).

Table 15.

Figure 3.

Comparative Examples H-L (C.E.-H to C.E.-L)

To compare the gas generation of bicarbonate and carbonate -based formulations, sodium bicarbonate and sodium carbonate were mixed with sodium bisulfate or citric acid and the resultant mixture was sealed in a PVA bag. The compositions are shown in Table 16. The PVA bags containing the mixture were aged at 70 °C (158 °F) for 2 hours.

Comparative Examples H-I generated gas, inflating the PVA bag, while Comparative Examples J-L did not generate gas.

Table 16.

Comparative Example M (C.E-M)

About 24.9 g of sodium persulfate, 173.7 g of sodium bisulfate, 94.5 g of sodium carbonate and 2.4 g of CAB-O-SIL M-5, 6.0 g of SIPERNAT 50S, 6.0 g of cornstarch, 7.5 g of LANTHANOL LAL and 4.5 g of STEPANOL WA-100 NF/USP were added to a glass vial, followed by manual tumbling to form a powder mixture, shown in Table 17. The powder mixture was free floating.

Table 17.

For hard water stain removal test, about 5 g of sodium bisulfate and 5 g of citric acid were added to 20 g of the powder mixture. About 30 g of the powder mixture was used as a control. Both mixtures were then tested for hard water stain removal using the test methods described above. The powder mixture containing sodium bisulfate and citric acid showed about 60% removal with higher foaming while the powder mixture alone showed about 50% removal of hard water stains. About 20 g of the powder mixture was aged in a PVA bag in an oven at 70 °C (158 °F) for 2 hours. The PVA bag was not inflated. PVA fdm used for the PVA bag is available from Aicello America Corp., Princeton, NJ. The PVA fdm thickness was typically 40 or 50 mil for the PVA bag.

Example 7

About 20.3 g of sodium persulfate, 173.9 g of sodium bisulfate, 76.9 g of sodium carbonate and 97.5 g of citric acid, 4.9 g of SIPERNAT 50S, 4.9 g of cornstarch, 6.1 g of LANTHANOL LAL and 3.7 g of STEPANOL WA-100 NF/USP were added to a glass vial, followed by manual tumbling to form a powder mixture, shown in Table 18. The powder mixture was free floating. About 30 g of the powder mixture was sealed in a PVA bag. Table 18.

The sealed powder mixture was aged in an oven at 70 °C (158 °F) for 161 hours. The inflation of PVA bag was rated from 0-1 (with 0 having no inflation and 5 being fully inflated). About 20 g of the powder mixture was then used for hard water stain removal and foaming height testing using the test methods described above. Visual observation of the hard water stain removal was determined to be about 80% and the maximum foaming height was measured to be about 1.6 cm.

Example 8

About 10.0 g of sodium persulfate, 173.9 g of sodium bisulfate, 76.9 g of sodium carbonate, 97.5 g of citric acid, 5.0 g of SIPERNAT 50S, 6.1 g of LATHANOL LAL and 3.7 g of STEPANOL WA-100 NF/USP were added to a glass jar, followed by manual tumbling to form a powder mixture, shown in Table 19. The powder mixture was free floating. About 30 g of the powder mixture was sealed in a PVA bag.

Table 19.

The sealed sample was aged in an oven at 70 °C (158 °F) for 136 hours. The inflation of PVA bag was rated as 1-2 (with 0 as no inflation and 5 as being fully inflated). About 20 g of the powder mixture was then used for hard water stain removal and foaming height testing using the test methods described above. Visual observation of the hard water stain removal was determined to be about 85% and the maximum foaming height was measured to be about 1.4 cm.

Example 9

About 2.68 g of sodium persulfate, 24.0 g of sodium bisulfate, 26.6 g of sodium carbonate, 42.7 g of citric acid, 1.34 g of SIPERNAT 50S, 1.64 g of LATHANOL LAL, and 0.98 g of STEPANOL WA-100 NF/USP were added to a glass jar, followed by manual tumbling to form a powder mixture, shown in Table 20. The powder mixture was free floating.

Table 20.

About 20 g of the powder mixture was then used for hard water stain removal and foaming height testing using the test methods described above. Visual observation of the hard water stain removal was determined to be about 55% and the maximum foaming height was measured to be about 1.6 cm.

Comparative Examples N-P (C.E.-N to C.E.-P)

Comparative Examples N-P were tested for weight loss using TGA. High resolution TGA was performed by ramping up temperature at 20 °C/min from room temperature to 250 °C. The measurements and results are shown in Table 21 and Figure 4.

Table 21.

Figure 4.

Example 10

About 23.6 g of sodium bisulfate, 26.1 g of sodium carbonate, 42.1 g of citric acid, and 1.28 g of SIPERNAT 50S were added to ajar, followed by manual tumbling to form a powder mixture, shown in Table 22. About 2.47 g of LATHANOL LAL and 1.48 g of STEPANOL WA-100 NF/USP were first mixed in ajar followed by adding about 0.30 g of SZ 41894 Citrus and manual tumbling. The two mixtures were combined and about

0.0065g of Duasyn Ink Blue SLK was added. The final mixture was further homogenized using a mechanical stirrer for 1 hour.

Table 22.

30 g of the powder mixture was then used for hard water stain removal, limescale removal, and foaming height testing using the test methods described above. Visual observation of the hard water stain removal was determined to be about 65% and the maximum foaming height was measured to be about 2.2 cm. Limescale removal was measured to be about 0.111%.

Example 11

About 2.7 g of sodium persulfate, 23.9 g of sodium bisulfate, 26.5 g of sodium carbonate, 42.7 g of citric acid, and 1.3 g of SIPERNAT 50S were added to ajar, followed by manual tumbling to form a powder mixture, shown in Table 23. About 1.6 g of LATHANOL LAL and 1.0 g of STEPANOL WA-100 NF/USP were mixed in a jar followed by adding about 0.30 g of SZ 41894 Citrus and manual tumbling. The two mixtures were combined and about 0.0065g of Acid Blue 9 was added afterwards. The final mixture was further homogenized using a mechanical stirrer for 1 hour.

Table 23.

About 30 g of the powder mixture was then used for hard water stain removal, limescale removal, and foaming height testing using the test methods described above. Visual observation of the hard water stain removal was determined to be about 58% and the maximum foaming height was measured to be about 2.4 cm. Limescale removal was measured to be about 0.09%. About 4g of Example 11 were added into about 100 g of tap water in a 1 L graduated cylinder and the maximum foaming was recorded as about 8.3 cm.

Various modifications and alterations to this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure. It should be understood that this disclosure is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the disclosure intended to be limited only by the claims set forth herein as follows. All references cited in this disclosure are herein incorporated by reference in their entirety.

Claims

What is claimed is:

1. A cleaning composition comprising: a gas generator having particle sizes of between about 44 and about 2000 pm; an acid having particle sizes of between about 44 and about 4000 pm; a chelating agent having a particle size of between about 74 and about 4000 pm; and a surfactant, wherein the solid cleaning composition has a pH of between about 0 and about 5 when dissolved in water, wherein a weight ratio of gas generator to acid is between about 1:0.6 to about 1:3, and wherein a weight ratio of acid to chelating agent is between about 1:0.4 and about 1:3.

2. The cleaning composition of claim 1, wherein the solid cleaning composition has a pH of between about 1 and about 5.

3. The cleaning composition of claim 1, wherein the gas generator is one of sodium carbonate or sodium bicarbonate.

4. The cleaning composition of claim 1, wherein the acid is sodium bisulfate.

5. The cleaning composition of claim 1, wherein the chelating agent is citric acid.

6. The cleaning composition of claim 1, further comprising an oxidizer.

7. The cleaning composition of claim 6, wherein the oxidizer is one of sodium percarbonate and sodium persulfate.

8. The cleaning composition of claim 1, wherein the cleaning composition is in pod or tablet form.

9. The cleaning composition of claim 8, wherein the cleaning composition is in pod form, and wherein the pod is formed of a water-soluble polymer fdm.

10. The cleaning composition of claim 1, wherein the gas generator has particle sizes of between about 74 and about 1000 pm.

11. The cleaning composition of claim 1, wherein the chelating agent has a particle size of between about 250 and about 2000 pm.

12. The cleaning composition of claim 1, wherein the acid has a particle size of between about 500 and about 1500 pm.

13. The cleaning composition of claim 1, further comprising a biocide.