GB2061996A

GB2061996A - Lavatory cleansing blocks

Info

Publication number: GB2061996A
Application number: GB7932840A
Authority: GB
Original assignee: Jeyes Group Ltd
Current assignee: Jeyes Group Ltd
Priority date: 1979-09-21
Filing date: 1979-09-21
Publication date: 1981-05-20
Also published as: GB2061996B

Abstract

A process for the preparation of a lavatory cleansing block consisting essentially of: (a) from 5 to 90% by weight of a surface active component comprising one or more organic surface active agents; (b) from 0.5 to 75% by weight of one or more binders selected from clays and water-soluble or water- dispersible gel-forming organic polymeric materials; (c) from 0 to 20% by weight of one or more dyestuffs or other colouring agents; (d) from 0 to 35% by weight of a perfume component; (e) a total of from 0 to 75% by weight of (i) one or more inert water- soluble fillers, (ii) one or more water-softening or chelating agents, (iii) one or more solid water- soluble acids or acid-release compounds; and (iv) one or more inert water- insoluble inorganic or polymeric organic fillers (in an amount of not more than 50% by weight of the block); and (f) from 0 to 20% by weight of one or more germicides, fungicides and/or chlorine release agents; comprises forming a melt of those components of the block having a melting point of from 25 to 100 DEG C, uniformly dispersing in the melt any components of the blocks having a melting point above the temperature of the melt and/or any components of the block which are liquids at ambient temperature, casting the resultant composition into a mould and cooling the composition in the mould to form a solid block.

Description

SPECIFICATION Lavatory cleansing blocks This invention is concerned with improvements in and relating to blocks for cleansing lavatory bowls or urinals.

More particularly, this invention is concerned with cleansing blocks which are immersed in the flush-water cistern of a lavatory bowl or urinal and are slowly dissolved in the water therein, thereby to release active ingredients contained in the blocks to the water, which active ingredients serve to assist in cleansing the lavatory bowl or urinal when water is flushed from the cistern into the lavatory bowl or urinal. Such blocks generally comprise two types, the "containerised" type and the "naked" type. In the case of the former, the block is contained in a suitable container generally so arranged as to allow for a more or less metered dose of the block to be dissolved into the flushing water in the cistern each time the lavatory bowl or urinal is flushed.The "naked" block does not involve the use of such a container, the solubility characteristics of the block being such that the block only slowly dissolves to release its active ingredients to the water in the cistern.

In both cases the composition of which the block is formed generally comprises a water-soluble surface active agent to impart cleansing or detergent properties to the flush water and in the case of the naked block the composition also contains one or more hydrophobic materials or relatively waterinsoluble materials to slow down the rate of dissolution of the block. The formulation of a naked block is thus so arranged that the block, which is wholly immersed in the water of the cistern, slowly dissolves in the water of the cistern over a fairly extended period of time.

It has now been found, in accordance with the present invention that the incorporation of certain binder materials in a naked block serves to decrease the rate of dissolution of the block.

Accordingly, one embodiment of the present invention provides a process for the preparation of a lavatory cleansing block consisting essentially of: (a) from 5 to 90% by weight of a surface active component comprising one or more organic surface active agents; (b) from 0.5 to 75% by weight of one or more binders selected from clays and water-soluble or water-dispersible gel-forming organic polymeric materials; (c) from 0 to 20% of one or more dystuffs or other colouring agents; (d) from 0 to 35% by weight of a perfume component; (e) a total from 0 to 75% by weight of (i) one or more inert water-soluble fillers; (ii) one or more water-softening or chelating agents; (iii) one or more solid water-soluble acids or acid-release compounds; and (iv) one or more inert water-insoluble inorganic or polymeric organic fillers (in an amount of not more than 50% by weight of the mixture); (f) from 0 to 20% by weight of one or more germicides, fungicides, and/or chlorine release agents; which comprises forming a melt of those components of the block having a melting point of from 25 to 1 O00C, preferably from 35 to 700 C, uniformly dispersing therein any components of the block having a melting point above the temperature of the melt and/or any components of block which are liquids at ambient temperature, casting the resultant composition into moulds and cooling the composition in the moulds to form solid blocks.

The invention also provides lavatory cleansing blocks when produced by the above process.

The two essential ingredients of the blocks of the invention are (a) an organic surface active agent component and (b) a binder component and in its simplest form the blocks may comprise only these two ingredients. However, the blocks produced in accordance with the invention may, and frequently desirably do, contain other ingredients as indicated above.

One principal and essential ingredient of the particulate mixture is the binder. This may be a clay, such as bentonite or Laponite, or; preferably, a water-soluble or water-dispersible gel-forming organic polymer. The term "gel-forming" as applied to this polymer is intended to indicate that on dissolution or dispersion in water it first forms a gel which, upon dilution with further water, is dissolved or dispersed to form a free-flowing liquid.

The binder is believed to serve in controlling the rate of dissolution of the block. Thus, whilst we do not wish to be limited by theoretical considerations, it is believed that the mode of dissolution of the block of the invention is somewhat as follows. The block is introduced into the cistern containing water and sinks to the bottom (as discussed below the block should have an apparent specific gravity greater than that of water to ensure that it does so).The water in the cistern dissolves or disperses a part of the exposed surface of the block and, in consequence of the presence of the binder a layer of thickened gelled solution is formed around the block. (Where the binder is a clay it is believed that a thickened solution of surface active agent containing dispersed binder is formed whereas where the binder is a gel-forming polymer a gel containing dissolved surface active agent is formed).

Since the water in the cistern is comparatively still this layer tends to remain in contact with the block (although of course some diffusion of the gel layer to the body of the water in the cistern will occur, but only slowly), thereby tending to isolate the block from the body of water in the cistern thereby protecting or retarding further dissolution of the block. When the cistern is flushed the movement of the outgoing water removes at least a part of the thickened or gelled layer and due to the agitation and turbulence of the outgoing water this layer is dispersed and dissolved in the flushed water. The cistern is then refilled with water until relatively still water conditions obtain in the cistern and, as described above, a thickened or gelled layer again forms around the block.

A wide variety of water-soluble polymers are suitable for use in accordance with the invention.

Such polymers may be wholly synthetic or may be semi-synthetic polymers derived from natural materials. Thus, for example, one class of polymers for use in accordance with the invention are chemically modified celluloses such as ethyl cellulose, methyl cellulose, sodium carboxymethyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, and hydroxyethyl cellulose. Another class of polymers which may be used are naturally derived polymeric materials such as alginates and caragheenates; alternatively the semi-synthetic analogues thereof produced by fermentation processes may also be used. Similarly, water-soluble starches and gelatin may be used as organic polymers in accordance with the invention.

The cellulose based binders are a preferred class of binder for use in the invention and may possess the property of inverse solubility that is their solubility decreases with increasing temperature, thereby rendering the tablets of the invention suitable for use in locations having a relatively high ambient temperature.

Wholly synthetic polymers which may be used in accordance with the invention include polyvinyl alcohols; water-soluble partially hydrolysed polyvinyl acetates; polyacrylonitriles; polovinyl pyrrolidones; water-soluble polymers of ethylenically unsaturated carboxylic acids, such as acrylic acid and methacrylic acid, and salts thereof; base-hydrolysed starch-polyacrylonitrile copolymers; polyacrylamides; ethylen oxide polymers and copolymers; and carboxypolymethylenes.

In the case of the organic polymeric binders it may be noted that, in general, the higher the molecular weight of the polymer the greater the in-use life of the block, other things being equal. The total binder content of the block is from 0.5 to 95% by weight, preferably from 1 to 70% by weight, more preferably from 5 to 60% by weight.

As will be appreciated, certain of the gel-forming polymers envisaged for use in accordance with the invention also have surface active properties and thereby serve not only as binders but also enhance the cleansing ability of the blocks of the invention. Further certain organic polymers, such as substituted cellulose, also serve as soil antiredeposition agents.

The second essential ingredient of the blocks comprises on or more surface active agents and it is generally preferred that at least one of these be one capable of forming the base melt. The surface active component may comprise an anionic, nonionic, cationic or amphoteric surface active agent or mixture thereof. Suitable anionic surface active agents include, for example, alkali metal salts of alkyl substituted benzene sulphonic acids, alkali metal salts of long chain fatty sulphates, alkali metal ether sulphates derived from alcohols and alkyl phenols, alkali metal sulphosuccinates, alkali metal sarcosinates and alkali metal taurides.

(It may be noted that in general anionic surface active agents do not melt in the required temperature range and hence should be employed in admixture with suitable components capable of melting, preferably other surface active agents such as nonionic surface active agents).

Suitable nonionic surface active agents include, for example, alkylene oxide condensates of fatty acids, fatty alcohols or alkyl substituted phenols; ethylene oxide/propylene oxide block copolymers; amine ethylates; fatty acid alkanolamides; sucrose surfactants and fatty acid alkanolamide ethoxylates.

Suitable cationic surface active agents include quaternary ammonium bromides and chlorides containing surface active agents include quaternary ammonium bromides and chlorides containing a long chain alkyl group such as, for example, Centrimide or benzalkonium chloride. Suitable amphoteric surface active agents include so-called "betaine" type and imidazoline type surface active agents.

It may be noted that cationic surface active agents also often possess germicidal properties and thereby impart not only detergent activity but germicidal activity to the flushing water.

The surface active agent component will be present in the block of an amount of 5 to 90% by weight, preferably from 5 to 80% by weight, more preferably from 5 to 60% by weight. The most preferred content for surface active agent is from 10 to 40% by weight.

The blocks will generally also contain a dyestuff or other colouring agent such as a pigment in order to impart a pleasant coloration to the water and also to indicate to the user when the block has become exhausted (i.e., on exhaustion of the block the water becomes colourless). Accordingly, the block preferably contains a powdered solid dyestuff, suitably in an amount of up to 20% by weight, preferably in an amount of from 1 to 1 5% by weight, more preferably from 1 to 10% by weight. Suitable dyestuffs include, for example, acid blue and acid blue 9 type dyes.

The blocks may also contain perfumes to impart an acceptable odour to the flushing water. The perfume may be a solid perfume, which term is intended to include micro encapsulated perfumes (i.e.

liquid perfumes contained in a water-soluble microcapsule) or other solid perfumes materials such as paradichlorbenzene or diphenyl oxide. Alternatively the perfume may be a liquid and in this case the term liquid perfume is intended to cover not only poerfumes per se, but solution of perfumes in solvents therefor. The total amount of perfume should not be more than 35% by weight and is preferably from 2 to 20% by weight. It may be noted that the term "perfume" is intended to refer to any material giving an acceptable odour and thus materials giving a "disinfectant" odour such as pine oils, terphinolenes or paradichloro-benzene may be employed.

The blocks in accordance with the invention may also contain germicides, fungicides and/or chlorine release agents, especially when the surface active agent employed is not a cationic germicidal surface active agent. Suitable germicides include, for example, formaldehyde release agent, chlorinated phenols and suitable chlorine release agents include sodium dichloroisocyanurate. These components may be present in the blocks in amounts of up to 20% by weight, preferably from 1 to 15% by weight, although it is to be understood that where the surface active agent is germicidal, these weight limitations do not apply.

The blocks may also contain water-soluble fillers, for example organic fillers such as urea or watersoluble inorganic fillers such as sodium carbonate, sodium bicarbonate, sodium chloride, copper sulphate, sodium sulphate, borax, zinc sulphate and the like. It may be noted that where copper salts, such as copper sulphate, are employed as fillers they may also serve to impart fungicidal or fungistatic properties to the flush water.

Other ingredients which may be present in the blocks of the invention include water-softening or chelating agents, for example inorganic water-softening agents such as sodium hexametaphosphate or other alkali metal polyphosphates or organic water-softening agents such as ethylenediaminetraacetic acid and nitrilotriacetic acid and alkali metal salts thereof.

The blocks may also contain particulate solid water-insoluble fillers such as talc or particulate organic polymeric materials but these should not be present in an amount of more than 50% by weight of the mixture, preferably not more than 30% by weight of the mixture.

The mixture may also contain solid water-soluble acids or acid-release agents such as sulphamic acid, citric acid and sodium hydrogen sulphate.

Preferably the mixture will contain a total of from 0 to 60%, more preferably 20 to 50% by weight of water-soluble fillers, water-softening or chelating agents, water-soluble acids and water-insoluble particulate fillers.

The process of the invention makes it possible to produce lavatory cleansing blocks from ingredients which are readily water-soluble or water-dispersible, i.e. which readily form solutions or dispersions on contact with water, in contradistinction to the hydrophobic or difficulty water-soluble materials employed in prior art blocks.

As indicated above the process of the invention comprises first forming a melt of those ingredients of the block having a melting point of from 25 to 1 000C. One of these components will generally be a surface active agent or agents and, indeed, this will often be the only component melting within the desired range.

Generally in order to achieve a satisfactory product such melt forming components will form at least 25% by weight, preferably at least 50% by weight of the block. The remainder of the ingredients of the block, which are subsequently dispersed in the melt, should, of course, be stable at the melt temperature that is should not undergo thermal decomposition at the melt temperature nor should volatalise to too great an extent at the melt temperature. In order to overcome such problems it is therefore preferred that the melt be formed at a temperature at or only a few degrees above the melting point of the melt components.

The block formed in accordance with the invention suitably have a weight of from 20 to 1 50 grams, preferably from 30 to 60 grams.

The blocks produced in accordance with the invention may subsequently be provided with a coating of a water-soluble film, such as polyvinyl acetate, to make handling thereof more convenient.

The invention also provides a method of cleansing a lavatory or urinal which comprises immersing a block in accordance with the invention in the cistern thereof.

In order that the invention may be well understood the following Examples are given by way of illustration only.

EXAMPLES Lavatory cleansing blocks were prepared from each of the compositions listed in the table below by firstly melting the ingredient(s) of the composition indicated by (m) dispersing the remainder of the ingredients in the resultant melt by stirring; casting the resultant melt/dispersion into moulds of approximately 45 ml capacity; allowing the melt/dispersion to cool and solidifying in the moulds; and recovering blocks having a weight of about 50 grams from the moulds.

TABLE

% by weight of ingredient in block of Example Ingredient 1 2 3 4 5 6 7 8 9 10 11 SCMC 40 35 30 25 - - - - - - - HPC - - - - 40 20 - - - - HPMC 5000 - - - - - - 10 10 10 5 5 AEO2O (m) - - 45 - - - - - - - AEO5O (ml 30 30 - 35 - - - 50 30 - AEO8O (m) - - - - - - 50 - - - EO/PO (m) 5 10 5 5 35 40 - - - 40 45 NDBS - - - - - - - - - 30 25 Dye 1 4 4 4 4 - - - - - 4' 4' Dye - - - - 13 5 4 4 4 - - Terpinolene - 10 5 - 5 10 15 10 10 10 10 PDCB - - - 5 - - - - - - Hex 20 10 10 20 - - - - - 10 10 Sodium chloride - - - - 13 23 19.5 24.5 44.5 - Centrimide BP 1 1 1 1 2 2 1,5 1.5 1.5 1 1 NOTES SCMC = Sodium carboxymethylcellulose (Coulose A680) HPC - Hydroxypropylcellulose (Klucel J) HPMC 5000= Hydroxypropylmethylcellulose (Celacol HPM 5000) AEO20 = Ethoxylated fatty alcohol (20 moles EO/mole) (@mpilan KM50) AEO50 = Ethoxylated tatty alcohol (50 moles EO/mole) (Empilan KM50) AEO50 @@ Ethoxylated fatty alcohol (60 moles EO/mole) (Ethylan D2560) EO/PO = Ethylene oxide/propylene oxide block copolymer (Monolan 8000/E80) NDBS = Sodium dodecylbenzene sulphonate (Nansa HS 805) Dye 1 = Acid blue dye 1 Dye 9 = Acid blue dye 9 PDCB = Paradichlorobenzene Hex = Sodium hexametaphosphate

Claims

1. A process for the preparation of a lavatory cleansing block consisting essentially of: (a) from 5 to 90% by weight of a surface active component comprising one or more Qrnisnic surface active agents; (b) from 0.5 to 75% by weight of one or more binders selected from clays and water-soluble or water-dispersible gel-forming organic polymeric materials; (c) from 0 to 20% by weight of one or more dyestuffs or other colouring agents; (d) from 0 to 35% by weight of a perfume component; (e) a total of from 0 to 75% by weight of (i) one or more inert water-soluble fillers, (ii) one or more water-softening or chelating agents; (iii) one or more solid water-soluble acids or acid-release compounds; and (iv) one or more inert water-insoluble inorganic or polymeric organic fillers (in an amount of not more than 50% by weight of the block); and (f) from 0 to 20% by weight of one or more germicides, fungicides and/or chlorine release agents; which comprise forming a melt of those components of the block having a melting point of from 25 to 1 0O0C, uniformly dispersing in the melt any components of the blocks having a melting point above the temperature of the melt and/or any components of the block which are liquids at ambient temperature, casting the resultant composition into a mould and cooling the composition in the mould to form a solid block.

2. A process as claimed in claim 1 in which the melt is formed of components of the block having a melting point of from 35 to 700 C.

3. A process as claimed in claim 1 or claim 2 in which the ingredients of the block employed to form the melt form at least 25% by weight of the block.

4. A process as claimed in any one of the preceding claims in which the binder is a semi-synthetic gel-forming polymer.

5. A process as claimed in claim 4 in which the binder is a chemically modified cellulose.

6. A process as claimed in any one of the of the preceding claims in which the binder is present in the block in an amount of from 1 to 70% by weight of the block.

7. A process as claimed in claim 6 in which the binder is present in the block in an amount of from 5 to 60% by weight of the block.

8. A process as claimed in any one of the preceding claims in which the surface active component comprises one or more nonionic surface active agents.

9. A process as claimed in any one of the preceding claims in which the surface active component is present in the block in an amount of from 5 to 80% by weight of the block.

10. A process as claimed in claim 9 in which the surface active component is present in the block in an amount of from 5 to 60% by weight of the block.

11. A process as claimed in any one of the preceding claims containing from 1 to 1 5% by weight, based on the weight of the block, of a solid powdered dyestuff.

12. A process as claimed in any one of the preceding claims containing a total of from 0 to 60% by weight of component (e).

13. A process as claimed in claim 1 in which the block is in a mould to give a block having a weight of from 20 to 150 grams.

14. A process as claimed in claim 1 substantially as hereinbefore described with reference to the examples.

15. A lavatory cleansing block when obtained by a process as claimed in any one of the preceding claims.

1 6. A method of cleansing a lavatory or urinal which comprises immersing in the cistern thereof a block as claimed in claim 1 5.