CA2227803C

CA2227803C - Toilet bowl detergent system

Info

Publication number: CA2227803C
Application number: CA002227803A
Authority: CA
Inventors: Ricky Ah-Man Woo; Daniel Scott Cobb; Jeffrey Lawerence Flora
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1995-07-26
Filing date: 1996-07-25
Publication date: 2001-04-24
Anticipated expiration: 2016-07-25
Also published as: MX9800707A; EP0842258A1; US5562850A; BR9609753A; CO4750721A1; AU704769B2; AR003062A1; CA2227803A1; AU6599096A; JPH11510205A; WO1997005232A1

Abstract

Toilet bowl detergent compositions, preferably blocks of the "in-tank" or "rim-block" types, contain a cleaning system comprising: detergent surfactant of the amphoteric type, preferably zwitterionic, more preferably one that contains a carboxylate group and a cationic group, and even more preferably a fatty acid amidoalkylene betaine, and polycarboxylate chelating agent, preferably, citric acid, or similar polycarboxylic acid, are combined with some means of creating the desired concentration of the cleaning system in the toilet bowl water, preferably by means of blocks with a dissolution retarding system, preferably with the dissolution retarding system comprising a combination of water soluble cellulosic polymer, more preferably hydroxyethyl cellulose or hydroxypropyl cellulose and, polyethylene glycol containing polymer, any perfume present being selected to be mostly hydrophobic. The compositions have a pH, in use, of from about 4 to about 9 and the blocks are preferably extremely homogeneous. Processes for keeping toilet bowls clean are disclosed.

Description

2 PCT/IJS96/12248 TOILET BOWL DETERGENT SYSTEM
FIELD OF THE INVENTION
This invention relates to toilet bowl cleaners, especially those of the block type that typically either sit, or hang, in the water reservoir ("tank"), or hang on the rim of a toilet bowl and rely upon the water from the "flush" to dissolve a portion of the block io and wash the ingredients into the pooled water in the bowl. There is a continuing need for improved compositions of this type.
BACKGROUND OF THE INVENTION
Solid delivery systems provide effective and convenient treatment of the toilet bowl water through the use of slow dissolving blocks containing the desired cleaning ingredients. Solid blocks are extremely cost effective and typically contain materials to control dissolution. A variety of approaches have been used to control the release:
The actives can be selected to have the desired limited solubility as in U.S.
Pat.
4,820,449, Menke et al. or the actives can be incorporated into a microporous resin, as in U.S. Pat. 4,252,785, Isoldi.
2o Long-chain cellulosic polymers have been used as a major solid component to control dissolution and release of the active ingredients into the pooled water. For example, Barford et al., U.S. Pat. No. 4,269,723 teaches the use of water soluble, water dispersible clays and cellulosics to retard dissolution. Barford makes mention of chemically modified celluloses such as ethyl cellulose, methyl cellulose, sodium carboxymethyl cellulose, ethyl hydroxyethyl cellulose, and the like. Barford, et al., discloses a process for making lavatory cleansing blocks by tableting a free flowing particulate mix consisting essentially ot; on a weight basis, from 5 to 90% of a surface active component and from 0.5 to 75% of one or more binders selected from clays and water soluble or water dispersible gel fonming organic polymeric materials.
3o Various optional components are also mentioned by Barford; namely, dyestuffs, perfume, water soluble fillers, water softening or chelating agents, solid water soluble acids, inert water insoluble inorganic or organic fillers, tablet lubricants, and agents having disinfecting or germicidal activity.
U.S. Pat. No. 4,460,490 to Barford, et al., discloses a freestanding lavatory cleansing block that comprises a shaped body formed of a slow dissolving cleaning composition containing a surface active agent and a tablet comprising a bleaching agent embedded in or adhered to the shaped body. The shaped body, according to the '490 patent, may be melt cast, tableted, or extruded, depending upon the geometry of the shaped body. The shaped body preferably comprises the aforesaid surface active agent and a solubility control agent, for example, a water soluble or water dispersible gel forming polymer, for example, chemically modified celluloses.
Ziek et al., U.S. Pat. No. 4,722,802, also discloses hydrated cellulosics to ,, retard dissolution. In Ziek et al., the advantages of curing the resultant block are also discussed. Similarly, Bunczak et al., U.S. Pat. Nos. 4,911,858 and 4,911,859, disclosed very high molecular weight polyethylene oxide polymers together with guar gum and calcium salt to form a gelatin matrix that slows dissolution of the solid 1o system.
Like Menke et al., U.S. Pat. No. 4,820,449, Jeffrey et al., U.S. Pat. No.
4,043,931, seeks slow dissolution through the use of mono- or di-alkanolamides of various aliphatic chain lengths while adding ethylene oxidelpropylene oxide block copolymer surfactants with unspecified monomer ratios. Jeffrey, et al., discloses a lavatory cleansing block comprising a solid carrier base which is a mixture of two or more nonionic surface active agents, one of which is relatively insoluble in water and the other of which is relatively soluble in water. The lavatory block of Jeffrey may optionally include perfume, dyestuff germicide, and fillers, the latter being for example, a water softener such as a alkali metal polyphosphate. The blocks of 2o Jeffrey are made by tableting.
Polyethylene glycol, having a molecular weight of about 8000, is taught in U.S. Pat. 5,342,550, Burke et al. together with one or more fillers or binding agents for use in solid block compositions. Examples of acceptable binding agents disclosed include the water-soluble alkali metal and alkaline earth metal salts. The compositions also preferably comprise one or more additional ingredients such as, for example, cleaning agents, deodorizers or perfumes, bactericides, bacteriostats, hard water film inhibitors, stain inhibitors and dyes.
U.S. Pat. No. 4,438,015 to Huber discloses lavatory cleansing blocks comprising as a solid carrier base a mixture comprising a major proportion of a 3o nonionic surface active compound and a minor proportion of a partially esterified copolymer of vinylmethyl ether and malefic anhydride (PVM/MA). The blocks of Huber are melt cast.
U. S. Pat. No. 4,229,410 to Kosti discloses a bacteriostatic toilet element comprising a water sensitive, water soluble or swellable binding agent and a bacteriostatic and/or deodorizing and/or coloring agent. Kosti's element may be melt cast or extruded.

-3-As discussed above, surfactant cleansing blocks can be made by tablet forming methods, casting or extrusion as described for instance in U.S. Pat. Nos.:

, 4,043,931; 4,269,723; 4,460,490; 4,438,015; 4 802; 4 728; and 4 , , , , , , .

The surfactant in these cleansing blocks is released gradually over an extended period ,~ 5 of time to clean the porcelain surface of the toilets.

Toilet bowl detergent compositions that are not blocks can also be used to form detergent solutions. There are a variety of dispensers that provide for controlled release. For example, U.S. Pat. 4,813.084, Buecheler et al., discloses a rim-block holder that can use granular compositions. Similarly, there are a multitude 0 of "passive" dispensers, such as U.S. Pat. 4,462,121, Dirksing et al., that can use liquid or solid compositions to form the cleaning solution in the toilet tank.

SUMMARY OF THE INVENTION

This invention relates to improved cleaning systems for toilet bowls that can operate at near neutral pH. The cleaning systems are especially useful in toilet bowl ~s block detergent compositions of the "tank" or of the "rim-block"
types. Such block detergent compositions contain tine cleaning system comprising:
detergent surfactant of the amphoteric type, preferably zwitterionic, more preferably one that contains a carboxylate group and a cationic group, and even more preferably a fatty acid amidoalkylene betaine, and polycarboxylate chelating agent, preferably, citric acid, or 2o similar polycarboxylic acid, together with a dissolution retarding system. For a rim-block type, the composition preferably comprises a combination of water soluble cellulosic polymer, more preferably hydroxyethyl cellulose or hydroxypropyl cellulose, having a Viscosity Grade, as defined by, e.g., Cellosize~ by Union Carbide, of from about 40 to about 100,000 and, polyethylene glycol containing 25 polymer, having a molecular weight of from about 1,000 to about 20,000, any perfume present being selected to be mostly hydrophobic.
For an in-tank block, higher molecular weights are required, as disclosed hereinafter.

The compositions herein have a pH, in use, of from about

4 to about 9, preferably from about 6 to about 8. The block compositions are preferably 3o extremely homogeneous. Homogeneity can be achieved, e.g., by milling the ingredients together to provide a matrix that contains essentially no large particles of any one ingredient. Other processes that provide similar mechanical energy, especially by shearing, can also be used. Homogeneity is determined by the smoothness of the surface, including the surface of any cross section of the block 35 after cutting.

The process herein involves using the cleaning system on a regular basis in toilet bowls, to maintain the cleanliness of the toilet bowl and prevent buildup of soil.

.;.
DETAILED DESCR.I~TION OF THE INVENTION
The Cleaning System AmDhotetic_ a g._ Zwitterionic Detergent SLrfacta_rt~
Zwitterionic drcergent surfactants contain both cationic and anionic hydrophilic

5 groups on the same molecule a a relatively wide range of pFfs. The typical cationic group is a quaternary ammonium group, although other positively charged groups like sulfonium and phosphonium groups can also be used. The typical anionic hydrophilic groups are carboxylates and sulfonates, although other groups like sulfates, phosphates, ac., can be used. A generic formula for some preferred 1o zwitterionic detergent surfactants ia:
R.I~+)(R2XR3~4X~~) wherein R is a hydrophobic group; R2 and R3 are each C 1.,4 alkyl, hydroxy alkyl or other subsLtuted alkyl group which can also be joined to form ring structures with the N; R4 is a moietyr joining the cationic nitrogen atom to the hydrophilic group and 1s is typically an alkrylena, hydroxy alkylme, or polyallcoxy group wherein the group contains from about one to about four wbon atoms; and X is the hydrophilic group which is preferably a carboxylate or sulfonate group, for example, a C1~ alkyl sulphonate group.
Preferred hydrophobic grarps R ue alkyl groups containing from about 8 to about 2Z, preferably lest than about 18, more preferably less than about 16, carbon 2o atoms. The hydrophobic group un contain un:attu~stioa and/or subst'rtuents and/or linking groups such as aryl groups, amido groups, eater group:,, etc. Ia general, fatty aryl amido alkcylene groups ue preferred.
A spea5c 'simple' zwitwionic daergea~t s;ufactant is 3-(N~dodecyl-N,N~
dimet~l}.2-hydrmry-ProPane-1~aulfonate, available from the Sheroc Company under 2s the trade name'Varioa HC.' Other specisc zwiawionic daergart aiufactants have the generic formula:
R.C(p).N(R~.(CR3~.N(RZ~(+).(CR3~ S03~-) wherein each R is a hydrocarbon group, e.g. an alkyl group containing from about 8 up to about 20, pcafaably up to about 18, moa pre5aablyr up to about 16 carbon aroma, 3o each (R~ is either a hydrogen (when sttached to the ~ido nitrogen), short chain a11cy1 or sub~rted allc~rl contaiai~ from one to about four arb~ atoms, preferably groups sdectod from the group con:asting of mahyl, ahYl. propyl, hyd:oxy subs akryl or propyl and mixtvra thaeol~ preferably mahyl, each (R3) is selectad from the group coasasting of hydrogen and hydroxy groups, and each n is a 3s numbs from 1 to about 4, preferably from 2 to sbout 3; more pr~aably about 3, with no more than about one hydroxy group in any (CR3~ moiety. The R groups can be bru~h~ and/or uns~u~ated, and such structiues as provide spotting/slming * Trade-mark benefits, even when used as part of a mixtwe with straight chain alkyl R
groups. The R2 groups can also be connected to form ring structures, A detergent surfactant of this type is a C 1 ~ 14 ~nY aoYlamidopropyleae(hydroxypropylene)sulfobetaine that is available from the Sherex Company under the trade name "Varion CAS
s Sulfobetaine".
Other zwitterionic daergent siufactants useful, and, surprisingly, preferred, herein include hydrocarbyl, e.g., fauyacyiamidoalkylene betsina. These detergent surfactants, which are more cationic at the pH of the composition, have the generic formula:
1o R-C(O)-N(R2~.(CR3~-N(RZ~t+)-(CR3~-C(p~(-) wherein each R is a hydrocarbon, e.g., as alkyl group containing from about 8 up to about 20, preferably up to about 18, more preferably up to about 16 carbon atoms, each (R.2) is either a hydrogen (when sttached to the amido nitrogen), short cheat alkyl, or substituted alkyl, containing from one to about four carbon atoms, 1s preferably groups selected from the group coasiatiag of methyl, ethyl, propyl, hydroxy substituted ethyl or propyl and mixtures thaeol~ preferably mahy<, each (R3) is selected from the group caasiating of hydrogen sad hydroxy groups, and each n is s rumba from 1 to about 4, preferably from 2 to about 3; more preferably about 3, with no more that about one hydroxy group is nay (CR3~ moiety. The R groups 2o can be breached and/or unsaturated, and such st:ucairea can provide :potting/filcaing benefits, oval when used as part of a mixture with straight chain alkyl R
groups.
Aa example of such a detergent s<ufactarrt is a C 12-i 6 ~y acyiatnidopropylbasiaa avai>able is a prefaced powder form from Golds~chmidt undo the trade name "Tego Betaiae D.' *
2s ?ha laud of is from about 10~/~ to about 90'X. by weight, preferably fi~ about 1 S to about 50'/~ by weight, and moat fly from about 20'/~ to about 35'~ by weight At the pFI of the composition is use, the carboxyl group is substantWly nonionic, although some portion a ionized to create a negative charge.
T1m cleaning systaa also comptixs polyrarboxyfic acid harag strong i ProP~~ for cdc~m at the use pI~ e.gy citric acid, or alt thaeo~
pr~efa~sbly sodium or potasriurn, or as equivalent polycarboacytic acid, or salt thereof.
Fqvivalent polyoarboxyiic acids have similar calaum binding coastaass sad include, for example, sucuaic, glutaric, adipic, malde, etc. 'T6e level of polycarboxyiic, e.g., citric acid, is preferably from aboirt 10'yt~ to about 90'/~ by waght, preferably from 33 about 15'/~ to about 50'/~ by weight, sad most preferably 5~om about 20'/~
to about ao~/. by waght.
* Trade-mark

-6-The combination of amphotericJbetaiae detergent ~ and polcarboxylidcitric acid type of chelating agent provides an unusually effective cleaning effect that prolongs the time that the bowl remains clean without need for mechanical cleaning effort.
5 The cleaning system preferably does not include any of the solid bleaching agents, especially chlorine bleaching agents, or phosphorous containing cleaning ingredients. The materials in the composition are preferably biodegradable to the maximum extent possible and are preferably safe to ux. It is desirable that such compositions not pox a threat to pets.
10 The Dissolution Rrtardiag,,~y~
The dissolution retarding system for block detergent compositions can be any one of the systems disclosed in the art, or heraRer. Preferably the dissolution system comprises wstc soluble cellulosic material. The primary dissolution retarding agent is preferably either hydroxypropyi cellulose or hydroxyethyt cellulose.
The is secondary dissolution resarding agate is preferably polyethylene glycol, ~
a polymer that contains a major pacattage of polyethylene glycol, so thst the polymer hu the characteristics of polyethylene glycol. Mmuu~a of these agents are preferably present in the block st a laud of from about i'/~ to about 60'/° by wdght, and, espedaUy for 'ia tank° blocks, preferably from about 10'/a to about 50%
by weight, 2o and most preferably from about 20~/~ to about 40'/~ by weight. In tank blocks require more dissohnion retarding agent since thry aro in water for the longest time.
Both of thex agents are non-ionic, water soluble, acid stable polymers and have the capacity of acting as dissohrtion retuding agents.
For rim-block types, preferably the hydroxyethyl and/or hydroxypropyl 25 cellulose has a V'vcosity Giad~ as defined is the Union Carbide publicstion Cdlosize,*of 5bm about 44 to about 100,000, preferably 5om about 10,000 to about 30,000, sad hu a degroe of hydroxyahyl or hydroxyrpcopyl substitution of from about 0.5 to about 2.5, pcefaably 8rom about 0.83 to about 1.55, and more pre&rsbly from about 0.9 to abort 1. 'The polyethylene glycol has a molecular 3o weight 5nm about 1,000 to about 20,000, preferably form about 2,000 to abet 8,000.
For in-teak block types, prafasbly higher molearlar weights ua preferred.
Typic:liyr, the ceilulOSic poiymQS are those thst have a Brookfield viscosity at 25°C
sad at 1'/a concentration in water of from about 1,000 to aboirt 5,000, e.g., 3s Nstrosol~ braa~d gtaada of from Ivgi to HI;, available 8rom Haatles, Inc.
Similarly, the other polymer is poly(ethyiene oxide) which has a molecular weight of from about 2x105 to about 5x106 preferably from about 1x106 to about 5x106, e.g., * Trade-mark _7_ Polyox~ WSR 3b1 or Polyox Coagulant from Union Carbide.
The ratio of cellulosic material to polyethylene glycol (or their equivalents) is from about 0.1 to about oo, preferably from about 0.5 to about 30, more preferably from about 1 to about 10.
s The blocks contain relatively high levels of perfumes to impart an acceptable odor to the composition and subsequently to the treated water, and may include essential oils and pine extracts, terpinolenes, bornyl acetate, etc., as well as others known in the art. The level of perfume is preferably from about 0.196 to about 20 l , preferably from about 1 ~& to about 15, more preferably from about 3 °6 to to about 8 °6 . These high levels of perfume can drastically affect the dissolution rate.
Preferably, the perfume that is present should be relatively hydrophobic, especially in rim-block compositions, to avoid increasing the dissolution rate and the block should be homogeneous, as disclosed before, in order to minimize the presence of holes in the block and of water soluble areas that dissolve to create holes in the block.
15 Other dissolution retarding agents can be present. Other dissolution retarding agent modifiers include water dispersible, acid stable polyalkoxylated cetyl alcohol or stearyl alcohol, or a mixture thereoiy containing from about 2 to about 8 alkyleneoxy units per molecule, preferably from about 4 to about 6 units, and having a molecular weight of from about 360 to about 650. The allcyleneoxy units are preferably 2o ethyleneoxy. The level of dissolution is controlled to provide a level of cleaning actives (cleaning system ingredients) in the toilet bowl water of from about 1 ppm to about 1000 ppm, preferably from about 5 ppm to about 50 ppm, more preferably from about 10 ppm to about 30 ppm, the ratio of detergent surfactant to polycarboxylic acid being from about 1:100 to about 100:1, preferably from about 25 1:10 to about 10:1, and more preferably from about 1:3 to about 3:1.
The rate of dissolution for block detergent compositions can be adjusted by incorporating larger or smaller amounts of the various dissolution retarding agents to provide lesser and greater rates of dissolution. For example, for any given hanger that holds the block, and for any given type of toilet which has a given flow of water, 3o there will be an optimum dissolution rate. In general, the cellulosic material will provide the greatest resistance to dissolution. The polyethylene glycol will provide less resistance, and the perfume selection and homogeneity will affect the dissolution rate. Within the limits given herein before, one can adjust the dissolution system based upon the level of cleaning system actives, the surface area of the block that is 35 exposed to the water flow by the hanger, the type and level of perfume present, and the desired level of cleaning ingredients in the bowl water. By adjusting the amounts and identities of erosion rate modifiers, the dissolution rate can be readily adjusted to _g_ create the desired level of cleaning ingredients in the bowl. The life of the block can be varied from about one to about five months by adjusting the size of the block.
9ntional Ingredients The composition according to the invention can also, preferably, comprise one or more additional ingredients such as, for example, bactericides, bacteriostats, f hard water film inhibitors, stain inhibitors and dyes. These additional ingredients can be present in the composition in total amounts of from about 0.1% to about 20%
by weight, preferably about 1% to about 15% by weight and most preferably about 3%
to about 10% by weight of the composition.
1o Bactericides and bacteriostats are those agents which inhibit and kill germs and other undesirable organisms. These may include, for example, quaternary ammonium materials, oxygen bleaches like monopersulfates (typically potassium salts), etc. as well as others known to those skilled in the art. In general, however, these are not needed in the present invention.
Hard water inhibitors and stain inhibitors may include polymers such as sodium polyacrylates or copolymers of malefic and acrylic acids.
Dyes are those ingredients which typically impart a pleasing color to the composition, and can include any of the known blue, green or violet dyes.
Process for Manufacture 2o Although the solid block, controlled release compositions herein can be prepared by any known process, such as casting, molding or tablet compression, the compositions are preferably prepared by imparting mechanical energy and shearing forces to the composition, e.g., by milling the various ingredients, to effect a highly homogeneous mass and then extruding the mass. The extruded shape is then cut into convenient sizes, stamped, if desired, and packaged, preferably in association with a "hanger" that keeps the block in position where the water can erode the block and effect release of the cleaning system. Preferably, there should not be any large areas of water soluble ingredients in the block. As discussed herein before, the desired degree of uniformity will be accompanied by a smooth appearance of the surface, and of any cross section that is cut. The blocks of the invention can be molded into numerous shapes and sizes, but it is preferable that the blocks range in weight of from about 40 to about 120 grams to provide a life of from about four weeks to about four months.
All percentages, parts, and ratios herein are "by weight" unless otherwise stated and all numbers are approximations to account for normal variations in measurements.
The invention is illustrated by the following non limiting Examples.

E XAMPLE
I

Toilet Rim-Block Compositions EXAMPLE . 1 2 3 I

Component Wt. Wt. % Wt. % Wt.
%

Cocoamidopropylbetaine' 21 25 17 25 Sodium Citrate 25 30 20 32 Perfume (Hydrophobic) 6 5 7 Polyethylene Glycol (MW-8000)25 32 20 20 Hydroxyethyicellulox (VG-40) 5 - _ Hydroxyethyicellulox (VG~30,000)20 - 35 Hydmxyethyicellulox (VCr100,00)_ _ _ 15 Blue Dye (0.45% solution)1 4 0 SoR Water 2 3 1 3 Tos~r 100 100 loo 100-'C1216 ~Y doproPY from Goldschmidt ('Tego Besaine D).

Toilet Ia-Tank Block Compo:itloae EXAMPLE i I 3 4 Component Wt. x Wt. Y~ Wt. Wt.
x y~

Cocoamidopropyibdaina' 29 26 Z3 24 Sodium Citrate 27 27 27 27 Pa$rme (Hydrophobic) 1 1 1 1 .

Hydrmcyahy1ce11uloee (Haaulx Nstrosol 250- * * 9 is 27 27 Poly~ooc WSRm Coal (Union Carbldo) 27 13 9 9 Bhts Dya (0.45'X eohstson)1 1 1 1 So8 Water 6 9 12 9 ._ _. - ._.
Tote( 100 100 100 100 s 'C12-16 ~Y ~~ProPY~m Goldachmidt (Te~o Betaine D).
** Trade-mark

Claims

WHAT IS CLAIMED IS:

1. A block detergent composition for keeping a toilet bowl clean comprising:
a cleaning system comprising: detergent surfactant of the amphoteric type and polycarboxylate chelating agent, the ratio of said surfactant to said chelating agent being from about 1:100 to about 100:1; and system for providing a concentration of from about 1 ppm to about 1000 ppm of said detergent surfactant and said chelating agent in the water of said toilet bowl;
said system being a dissolution retarding system which comprises a mixture of (1) a water soluble cellulosic material; and (2) polyethylene glycol, or a polymer that contains a major percentage of polyethylene glycol so that the polymer has the characteristics of polyethylene glycol; said mixture being at a level of from about 5% to about 60% by weight of said composition; and said water in said toilet bowl having a pH of from about 6 to about 8.

2. The composition of Claim 1 wherein said detergent surfactant has the formula:
R-N(+)(R2)(R3)R4X(-) wherein each R is a hydrophobic group; R2 and R3 are each C1-4 alkyl, hydroxy alkyl or other substituted alkyl group which can also be joined to form ring structures with the N; R4 is a moiety joining the cationic nitrogen atom to the hydrophilic group X.

3. The composition of Claim 2 wherein each R is a hydrophobic group containing from about 8 to about 22 carbon atoms and can contain unsaturation and/or linking groups selected from the group consisting of: aryl groups, amido groups, ester groups, and mixtures thereof.

4. The composition of Claim 3 wherein said unsaturation and/or linking groups are selected from the group consisting of a fatty acylamidoalkylene group.

5. The composition of Claim 2 wherein R4 is selected from the group consisting of an alkylene, hydroxyalkylene, or polyalkoxy group containing from about one to about four carbon atoms.

6. The composition of Claim 2 wherein X is a cation selected from the group consisting of carboxylate group, C1-4 alkyl sulfonate group, or mixtures therof.

7. The composition of Claim 1 wherein said detergent surfactant has a fatty acylamidoalkylene group; R2 and R3 are each C1-4 alkyl, hydroxy alkyl or other substituted alkyl group which can also be joined to form ring structures with the N; R4 is a moiety joining the cationic nitrogen atom to the hydrophilic group X.

8. The composition of Claim 2, 3, 4, 5 or 6 wherein said detergent surfactant has the formula:
R-C(O)-N(R2)-(CR3 2)n -N(R2)2 (+)-(CR3 2)n -C(4)O(-) wherein each R is a hydrocarbon group containing from about 8 up to about 20 carbon atoms, each (R2) is either hydrogen when (R2) is attached to the amido nitrogen, or short chain alkyl or substituted alkyl containing from one to about four carbon atoms, each (R3) is selected from the group consisting of hydrogen and hydroxy groups, and each n is a number from 1 to about 4, with no more than about one hydroxy group in any (CR3 2) moiety.

9. The composition of Claims 1, 2, 3, 4, 5, 6 or 7 wherein said polycarobxylic acid is selected from the group consisting of: citric acid; succinic acid, glutaric acid, adipic acid, maleic acid; mixtures thereof, or salt thereof.

10. The composition of Claim 8 wherein said polycarobxylic acid is citric acid.

11. The composition of claims 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 wherein the level of said polycarboxylic acid is from about 10% to about 90% by weight.

12. The composition of Claim 11 wherein the level of said polycarboxylic acid is from about 15% to about 50% by weight.

13. The composition of Claim 12 wherein the level of said polycarboxylic acid is from about 20% to about 40% by weight.

14. The composition of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13 comprising dissolution retarding system which comprises a mixture of (1) cellulosic material that is either, hydroxypropyl cellulose or hydroxyethyl cellulose, and (2) polyethylene glycol or poly(ethylene oxide), or a polymer that contains a major percentage of polyethylene glycol or poly(ethylene oxide), so that the polymer has the characteristics of polyethylene glycol or poly(ethylene oxide), said mixture being at a level of from about 5% to about 60% by weight of said composition.

15. The composition of Claim 11 wherein said dissolution retarding system is at a level of from about 10% to about 50% by weight the hydroxyethyl and/or hydroxypropyl cellulose has a Viscosity Grade of from about 40 to about 100,000, and a degree of hydroxyethyl or hydroxypropyl substitution of from about 0.5 to about 2.5, and the polyethylene glycol has a molecular weight from about 1,000 to about 20,000.

16. The composition of Claim 15 wherein said dissolution retarding system is at a level of from about 20% to about 40% by weight.

17. The composition of Claims 15 or 16 wherein the hydroxyethyl and/or hydroxypropyl cellulose has a Viscosity Grade of from about 10,000 to about 30,000.

18. The composition of Claims 15, 16 or 17 wherein the degree of hydroxyethyl or hydroxypropyl substitution is from about 0.85 to about 1.55.

19. The composition of Claims 15, 16, 17 or 18 wherein the polyethylene glycol has a molecular weight from about 2,000 to about 80,000.

20. The composition of Claim 11 wherein said dissolution retarding system is at a level of from about 10% to about 50% by weight, the hydroxyethyl and/or hydroxypropyl cellulose has a Brookfield viscosity at 25°C and at 1%
concentration in water of from about 1,000 to about 5,000, and a degree of hydroxyethyl or hydroxypropyl substitution of from about 0.5 to about 2.5, and the or poly(ethylene oxide) has a molecular weight from about 2x10 5 to about x 10 6.

21. The composition of Claim 20 wherein said dissolution retarding system is at a level of from about 20% to about 40% by weight.

22. The composition of Claims 20 or 21 wherein the or poly(ethylene oxide) has a molecular weight from about 1x10 6 to about 5x10 6.

23. An article of commerce comprising a hanger for a rim-block detergent block composition containing the composition of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22.

24. The process of cleaning a toilet bowl comprising providing from about 1 ppm to about 1000 ppm of a mixture of (1) detergent surfactant having the formula:
R-N(+)(R2)(R3)R4X(-) wherein each R is a hydrophobic group, R2 and R3 are each C1-4 alkyl, hydroxy alkyl or other substituted alkyl group which can also be joined to form ring structures with the N; R4 is a moiety joining the cationic nitrogen atom to the hydrophilic group X, and (2) polycarboxylic acid selected from the group consisting of: citric acid; succinic acid, glutaric acid, adipic acid, maleic acid;
mixtures thereof, or salt thereof, in a ratio of from about 1:100 to about 100:1.

25. The process of cleaning a toilet bowl of Claim 24 wherein said detergent surfactant has the formula:
R-C(O)-N(R2)-(CR3 2)n -N(R2)2(+)-(CR3 2)n -C(O)O(-) wherein each R is a hydrocarbon group containing from about 8 up to about 20 carbon atoms, each (R2) is either hydrogen when (R2) is attached to the amido nitrogen, or short chain alkyl or substituted alkyl containing from one to about four carbon atoms, each (R3) is selected from the group consisting of hydrogen and hydroxy groups, and each n is a number from 1 to about 4, with no more than about one hydroxy group in any (CR3 2) moiety; said polycarboxylic acid is citric acid; and the ratio of surfactant to citric acid is from about 1:3 to about 3:1, the level of surfactant and citric acid being from about 5 ppm to about 50 ppm.