WO1996004362A1

WO1996004362A1 - Toilet bowl cleaner

Info

Publication number: WO1996004362A1
Application number: PCT/US1995/009523
Authority: WO
Inventors: Deborah A. Quebedeaux; Joe D. Sauer; Patrick C. Hu
Original assignee: Albemarle Corporation
Priority date: 1994-08-01
Filing date: 1995-07-27
Publication date: 1996-02-15

Abstract

The longevity of a cleaning block containing a high sudsing amine oxide surfactant (e.g., N,N-dimethyltetradecylamine oxide) is increased by also including in the block at least one higher molecular weight amine oxide (e.g., N,N-dimethyloctadecylamine oxide), at least one soap, and at least one water-soluble alkali metal salt so that the block (1) has a water-soluble alkali metal salt content of 15-60 % by weight and a surfactant content of 10-70 % by weight and (2) contains as the surfactant a mixture of (A) 10-60 % by weight of a soap component and (B) 90-40 % by weight of a non-soap component having an amine oxide content of at least 15 % and containing as the amine oxide ingredient a mixture of 0.1-10 parts by weight of the higher molecular weight amine oxide and one part by weight of the high sudsing amine oxide.

Description

TOILET BOWL CLEANER

Field of Invention

This invention relates to blocks useful for cleaning toilet bowls via the flush water. More particularly, it relates to such blocks having good longevity.

Background

As taught in U. S. Patent 4,911 ,858 (Bunczk et al.), it is known that desirable effects such as bowl aesthetics, cleaning, and disinfection can be achieved by depositing a suitable shaped chemical composition, e.g., a tablet or cleaning block, in the cistern of a flush toilet so that the active ingredients are automatically dispensed into the bowl via the flush water each time the toilet is flushed. It is also known that practical utility in this application requires the cleaning block or other shaped chemical composition to be so formulated that it will have a long and uniform block life and provide evidence of its continuing effectiveness so that it can be replaced at the appropriate time.

When the function of the composition is merely to mask stains and/or odors, the dyes and/or fragrances used for that purpose provide their own evidence of continuing effectiveness; and dyes and/or fragrances may also be included in compositions intended primarily for cleaning purposes to provide an indication that the shaped composition in the toilet tank has not yet been devoided of its ingredients. However, even when the presence of such indicators in cleaning blocks is acceptable to the user, they do not provide reliable evidence of the continued presence of surfactant, since cleaning blocks do not necessarily release all of their ingredients at a uniform rate. It could therefore be very desirable to employ a high sudsing surfactant in a cleaning block so that its gradual release from the block could be monitored by the user.

U.S. Patent 4,731,223 (Forestier et al.) shows that cleaning blocks have been formed from compositions containing a particular high sudsing surfactant — N,N-dimethyldodecyla- mine oxide — and that the blocks retained cleaning effectiveness for two weeks. However, for practical reasons, a cleaning block should have greater longevity than can be achieved by the use of known compositions containing high sudsing amine oxide surfactants. Summary of Invention

It has now been found that the useful life of cleaning blocks containing high sudsing amine oxide surfactants can be extended when the blocks also contain higher molecular weight amine oxides and soaps as additional surfactants, as well as at least one water-soluble alkali metal salt. Thus, the cleaning blocks of the invention, suitable for insertion in the tank of a flush toilet, are cleaning blocks formed from a composition having a water-soluble alkali metal salt content of 15-60% by weight and a surfactant content of 10-70% by weight and containing as the surfactant a mixture of:

(A) 10-60% by weight of a soap component and (B) correspondingly, 90-40% by weight of a non-soap surfactant component having an amine oxide content of at least 15 % and containing as the amine oxide ingredient a mixture of (1) at least one amine oxide corresponding to the formula RR'TNO ^• «H₂O and (2) at least one amine oxide corresponding to the formula RR'T'NO ^• /ιH₂O in a weight ratio of 0.1-10/1, R and R' being independently selected from methyl, ethyl, and 2- hydroxyethyl, T being a primary alkyl group containing 16-24 carbons, T' being a primary alkyl group containing 8-14 carbons, and n representing 0, 1, or 2.

In a preferred embodiment, the invention resides in cleaning blocks which have no ingredients other than the water-soluble alkali metal salt(s) and surfactant mixture or which have as their only other ingredients up to 15% by weight of one or more oils, up to 20% by weight of one or more water-soluble dyes, up to 15% by weight of one or more antimicrobial agents, and up to 10% by weight of any additional adjuvants or fillers.

Detailed Description

The amine oxides utilizable in the practice of the invention are well known and include, e.g., N,N-dimethyloctyl-, N,N-dimethyldecyl-, N,N-dimethyldodecyl-, N,N- dimethyltetradecyl-, N,N-dimethylhexadecyl-, N,N-dimethyloctadecyl-, N,N-dimethyl- eicosyl-, N,N-dimethyldocosyl-, and N,N-<limemyltetraα)sylamine oxides; the corresponding N,N-diethyl-, N,N-di-2-hydroxyethyl, N-methyl-N-ethyl-, N-methyl-N-2-hydroxyethyl-, and N-ethyl-N-2-hydroxyethylalkyl amine oxides; and the corresponding amine oxide monohydrates and dihydrates. It is generally preferred that both the high sudsing amine oxides and those containing the larger alkyl groups be amine oxides in which at least some of the molecules are dihydrate molecules, i.e., the appropriate amine oxides described and claimed in U.S. Patent 5,075,501 (Borland et al.). Such amine oxides are commercially available from Albemarle Corporation under the tradename ADMOX*.

Although the objective of increasing the life of the cleaning block can be achieved when any one or more of the RR'TNO ^• «H₂O amine oxides is used in admixture with any one or more of the high sudsing RR'T'NO ^• «H₂O amine oxides, optimum results are apt to be obtained when the amine oxides are compounds wherein R and R' are methyl, T contains 16-18 carbons, and T' contains 12-14 carbons and when the T/T' weight ratio is in the range of 1.5-5.0/1. It is generally most preferred to employ mixtures of N,N- dimethyloctadecylamine oxide and N,N-dimethyltetradecylamine oxide, especially in a weight ratio of 2.9-3.0/1.

The surfactant may have no non-soap ingredients other than the amine oxide mixture. However, as already indicated, the desired results can also be achieved when the non-soap component ofthe surfactant contains up to 85% by weight of surfactants other than amine oxides. When such other surfactants are employed, they may be any anionic, cationic, nonionic, amphoteric, or zwitterionic surfactants which have melting points high enough to permit processing (usually higher than 43 °C, preferably higher than 50°C) or lower- melting surfactants that are present in amounts too small to interfere with processing. Exemplary of these optional components ofthe surfactant are the cationics known to be useful for their germicidal properties; salts of alkylbenzene sulfonates, alkyl sulfates, and olefin sulfates and sulfonates; alkoxylated fatty alcohols and alkylphenols; ethoxylated amines and amides; and the other surfactants commonly used in cleaning blocks. Of these surfactants, the anionic alkyl sulfates (especially sodium lauryl sulfate) are usually preferred.

The soap used in conjunction with the amine oxide mixture may be any alkali metal salt of a long-chain fatty acid, such as the sodium salts of lauric, palmitic, oleic, stearic, erucic, and cerotic acids. However, most conveniently, it is a soap derived from natural sources, e.g., a tallow or coco soap or mixture thereof. Of these soaps, tallow soap is ordinarily preferred, since its use in combination with the amine oxides and optional surfactant component appears to give the greatest longevity to the cleaning blocks. As already mentioned, the ingredients of the surfactant are employed in such amounts that the cleaning blocks have a surfactant content of 10-70% by weight, 10-60% of that weight being constituted by the soap component and 90-40% of that weight being constituted by the non-soap component. It is usually preferred, however, that the blocks have a total surfactant content of 30-60 % by weight, with 15-40 % of that weight constituted by the soap component and 85-60% of that weight constituted by the non-soap component. It is also generally preferable for the non-soap component to have an amine oxide content of at least 25%, most preferably at least 50%.

The water-soluble alkali metal salt constituting the remaining essential ingredient of the cleaning blocks functions inter alia to enhance the cleaning power and increase the specific gravity of the blocks. It may be a single salt or a mixture of salts that are preferably neutral or only mildly acidic or alkaline, e.g. , alkali metal carbonates, bicarbonates, sulfates, citrates, and phosphates. Although other alkali metal salts may be used, the sodium salts are preferred; and it is also generally preferred for at least 30% , more preferably at least 40%, of the weight of the salts to be provided by sodium citrate. Phosphates, when employed, should constitute not more than 10% of the weight of the blocks. In preparing the cleaning blocks of the invention, the amount of this ingredient utilized is such that the blocks have a water-soluble alkali metal salt content of 15-60%, preferably 20-55% by weight.

If desired, the aforementioned essential ingredients may be combined with certain other ingredients before being shaped into cleaning blocks, although the amounts of additional ingredients employed should be such that the essential ingredients constitute at least 50% of the weight of the cleaning blocks.

Among the optional ingredients apt to be desired in the preparation ofthe cleaning blocks are organic oils, which are beneficial in facilitating homogeneous blending of the constituents and, when perfumes, can also function as fragrances. Utilizable oils include, e.g., glycerin, low molecular weight polyethylene glycols, paraffimc and naphthemc hydrocarbons, and oily perfumes such as pine oil, eugenol, limonene, methyl salicylate, ethyl salicylate, and ethyl succinate. When employed, the oil component may be a single oil or a mixture of oils used in an amount such that the oil content of the cleaning block does not exceed 15% by weight and is usually in the range of 1-15% by weight. It is also permissible to include one or more water-soluble dyes in the cleaning blocks to color the aqueous media in which the blocks are placed — the amount included being such that the dye content of a block is not more than 20% by weight. Since blue is the color that appears to be most acceptable to cleaning block users, a particularly suitable dye is Colour Index No. dye 42,090.

When the cleaning blocks are intended to have a disinfecting function, they also contain up to 15 % by weight of one or more antimicrobials, such as those conventionally used in toilet cleaners, e.g., Dowicil 75, a product of Dow Chemical Company.

Other utilizable ingredients are additional adjuvants (e.g., die builders, chelating agents, sequestering agents, buffers, enzymes, bleaches, and bleach activators that have been found useful in known cleaning blocks) and fillers (such as sodium borate, magnesium chloride, magnesium sulfate, and high molecular weight polyethylene glycols and polypropylene glycols) which provide additional bulk and may enhance leaching out of the surfactant when the block is placed in water. When employed, the combined weights of these additional adjuvants and fillers should be such that they constitute not more than 10% of the weight of a cleaning block. The cleaning blocks of the invention are prepared by homogeneously mixing the desired ingredients in the proper amounts and shaping the resultant mixture into blocks having the desired size — typically cylinders having a weight of 30-100 grams, a length of 1.2-5.2 cm, and a diameter of 2.5-7.6 cm. Except for the use of the particular ingredients required for the preparation of the novel blocks, the mixing and shaping can be effected by any of the conventional techniques already employed in the preparation of cleaning blocks, e.g., the techniques taught in U.S. Patent 4,722,802 (Hutchings et al.).

The invention is advantageous in that it provides cleaning blocks which contain a high sudsing surfactant that permits easy monitoring of the continuing effectiveness of the blocks but which also have greater longevity than known cleaning blocks containing such high sudsing surfactants. These blocks resist sloughing and fragmentation, automatically dispense their cleaning agents and any other active ingredients (such as disinfectants, bleaches, dyes, and fragrances) in a uniform manner, and have a life which can be three or more times longer than the life of comparable blocks in which a high sudsing amine oxide is the only amine oxide ingredient. The following examples are given to illustrate the invention and are not intended as a limitation thereof. Unless otherwise specified, quantities mentioned in these examples are quantities by weight. Codes used in the examples have the meanings given below.

Code Definition

AX 1485 N,N-dimethyltetradecylamine oxide dihydrate, prepared essentially as in Borland et al.

AX 1885 N,N-dimethyloctadecylamine oxide dihydrate, prepared essentially as in Borland et al.

Oil 4243 HT a commercial pine oil

PVA a polyvinyl alcohol having a molecular weight of 86,000

SLS sodium lauryl sulfate

STPP sodium tripolyphosphate

EXAMPLE 1 Prepare a series of cleaning bars by homogeneously blending the ingredients in a Kitchen Aid blender and then in a Plodder mixer, extruding the blend at 50-55 °C, cutting the extrudate, shaping the cut extrudate into bars in a mold, and allowing the bars to set up for at least one hour. Then determine the relative longevity of each bar by ( 1 ) weighing the bar, (2) letting it stand overnight in a 5"x5" (12.7 cm x 12.7 cm) dish containing 100 mL of distilled water, (3) pouring the water out of the dish, scraping the soft slough from the bar, allowing the bar to dry until 4:00 p.m., and reweighing the bar, (4) repeating steps 2 and 3, and (5) calculating the wt% sloughing by dividing the average weight loss by the average initial weight of the bar and multiplying by 100. The ingredients used in preparing the different bars and the slough test results are shown in Table I.

TABLE I

Example 1-A 1-B 1-C 1-D 1-E

Tallow soap 9.8 9.8 9.9 9.8 10.0

AX 1485 4.9 4.9 9.9 4.9 5.0

AX 1885 14.6 14.6 9.9 14.6 15.0

SLS 18.6 18.6 18.8 18.6 19.0 Na₂SO₄ 34.2 34.2 34.6 34.2 35.0

Na₂CO₃ 7.8 7.8 7.9 7.8 8.0

Oil 4243 HT 6.0 — — — —

Pine oil 60 — 6.0 5.4 6.0 4.8

Pine oil 80 4.0 4.0 3.6 4.0 3.2

Slough (wt%) 2.3 2.4 2.6 1.5 2.0

As demonstrated by the low slough test results, each of the bars of Example 1 has a relatively slow dissolution rate that gives it a longer effective life. When used as cleaning blocks, these bars dispense their cleaning and fragrance components uniformly; and the foam provided by the AX 1485 permits monitoring of its continued presence until the bar is depleted of its active ingredients. The following example demonstrates the poorer longevity of bars containing AX 1485 as the sole amine oxide component.

EXAMPLE 2 (COMPARATIVE) Repeat Example 1 except for preparing the bars from the ingredients shown in Table π, which also shows the results of the slough test.

TABLE II

Example 2-A 2-B 2-C 2-D 2-E

Tallow soap 10.0 — 9.7 9.6 10.0

Coco soap — 10.0 — — —

AX 1485 20.0 20.0 19.3 19.1 20.0

SLS 19.0 19.0 18.4 18.1 19.0

Na₂SO₄ 35.0 35.0 33.9 33.5 35.0

Na citrate 8.0 8.0 7.7 7.7 —

STPP — — — — 8.0

Oil 4243 HT 4.8 4.8 6.6 7.2 4.8

Pine oil 80 3.2 3.2 4.4 4.8 3.2

Slough (wt%) 6.1 9.2 5.6 5.3 3.7

The subsequent example shows that cleaning blocks containing only AX 1885 can have the same good longevity as those containing both AX 1485 and AX 1885 — their inferiority being that they contain no high sudsing component to permit easy monitoring of the presence of surfactant in the blocks. The example also demonstrates the need for the surfactant to have a soap component in order for a cleaning block to be formed from the composition.

EXAMPLE 3 Repeat Example 1 except for preparing the bars from the ingredients shown in Table

UI, which also shows the results of the slough test. TABLE HI

Example 3-A¹ 3-B¹ 3-C

Tallow soap 9.6 -- 9.90

AX 1485 — 5.0 5.00

AX 1885 19.1 14.8 14.80

SLS 18.1 18.8 18.80

Na₂SO₄ 33.5 34.6 34.60

STPP 7.7 — —

Borax — 7.9 3.95

PVA — 9.9 3.95

Oil 4243 HT 7.2 5.4 5.40

Pine oil 80 4.8 3.6 3.60

2

Slough (wt%) 1.9 1.9

¹ Comparative examples

² Bars for slough test could not be formed.

Claims

1. A cleaning block which is suitable for insertion in the tank of a flush toilet, has a water-soluble alkali metal salt content of 15-60% by weight and a surfactant content of 10-70% by weight, and contains as the surfactant a mixture of: (A) 10-60% by weight of a soap component and

(B) correspondingly, 90-40% by weight of a non-soap surfactant component having an amine oxide content of at least 15 % and containing as the amine oxide ingredient a mixture of (1) at least one amine oxide corresponding to the formula RR'TNO ^• /ιH₂O and (2) at least one amine oxide corresponding to the formula RR'T'NO ^• nH₂O in a weight ratio of 0.1-10/1, R and R' being independently selected from methyl, ethyl, and 2- hydroxyethyl, T being a primary alkyl group containing 16-24 carbons, T' being a primary alkyl group containing 8-14 carbons, and n representing 0, 1, or 2.

2. The cleaning block of claim 1 wherein at least some of the amine oxide molecules are dihydrate molecules.

3. The cleaning block of claim 2 wherein R and R' are methyl, T contains 16-18 carbons, T' contains 12-14 carbons, and the T/T' weight ratio is in the range of 1.5-5.0/1.

4. The cleaning block of claim 3 wherein the amine oxide ingredient is a mixture of N,N-dimemyloctadecylamine oxide and N,N-dimethyltetradecylamine oxide in a weight ratio of 2.9-3.0/1.

5. The cleaning block of claim 1 wherein the non-soap component of the surfactant mixture contains at least one surfactant in addition to the amine oxide mixture.

6. The cleaning block of claim 1 consisting of:

(A) 10-70% by weight of a surfactant which is a mixture of:

(1) 10-60% by weight of a soap component and

(2) correspondingly, 90-40% by weight of a non-soap surfactant component having an amine oxide content of at least 15% and containing as the amine oxide ingredient a mixture of (1) at least one amine oxide corresponding to the formula RR'TNO ^• πH₂O and (2) at least one amine oxide corresponding to the formula RR'T'NO ^• ΛH₂O in a weight ratio of 0.1-10/1 , R and R' being independently selected from methyl, ethyl, and 2-hydroxyethyl, T being a primary alkyl group containing 16-24 carbons, T' being a primary alkyl group containing 8-14 carbons, and n representing 0, 1, or 2,

(B) 15-60% by weight of one or more water-soluble alkali metal salts,

(C) 0-15% by weight of one or more oils,

(D) 0-20% by weight of one or more water-soluble dyes,

(E) 0-15% by weight of one or more antimicrobial agents, and (F) 0-10% by weight of one or more additional adjuvants or fillers.

7. The cleaning block of claim 6 wherein the water-soluble alkali metal salt content is 20-55 % by weight, the surfactant content is 30-60 % by weight, the surfactant is a mixture of 15-40% by weight of the soap component and 85-60% by weight of the non-soap component, and the non-soap component has an amine oxide content of at least 25% by weight.

8. The cleaning block of claim 7 wherein R and R' are methyl, T contains 16-18 carbons, T' contains 12-14 carbons, and the T/T' weight ratio is in the range of 1.5-5.0/1.

9. The cleaning block of claim 8 wherein the amine oxide ingredient is a mixture of N,N-dimethyloctadecylamine oxide and N,N-dJ nemyltetradecylamine oxide in a weight ratio of 2.9-3.0/1.