Laundry additive substrate for stain removal

Abstract

 Additive products are provided for use in the washing of textiles comprising a mixture of an organic peroxy bleach precursor, a cationic surfactant and an alkoxylated nonionic surfactant of HLB 8 -17 in water releasable combination with a non-particulate substrate, the additive products being adapted for addition to conventional inorganic persalt- containing detergent liquors to enhance the removel of bleachable and greasy stains.

Description

[0001] This invention relates to detergent additive products intended for the washing of textiles and especially for the removal of stains from textiles, particularly oxidisable stains and those having an oily or greasy character.

[0002] In the Applicants' Swedish Patent Application No. 7711151-6 published on April 6th 1978 there is disclosed a laundry additive product comprising:

(a) a substrate in the form of a non-particulate solid article in water releasable combination with

(b) an organic peroxy compound precursor, wherein the weight ratio of the precursor to the substrate lies in the range 90:1 to 1:10.

[0003] The above disclosed invention is especially adapted for the removal of oxidisable stains from textiles when used in conjunction with conventional inorganic persalt- containing detergent compositions. It has now been found that certain mixtures of nonionic and cationic surfactants incorporated together with the organic peroxy compound precursor in water releasable combination with a non-particulate substrate provide enhanced removal of a broad range of stains especially greasy and oily stains. The effect is further increased when the additive product is used in conjunction with a conventional heavy duty laundry detergent containing an anionic surfactant and an inorganic persalt.

[0004] Accordingly the present invention provides a laundry additive comprising:

(a) a substrate comprising a non-particulate solid article in water-releasable combination with,

(b) an organic peroxy compound precursor wherein the weight ratio of the precursor to the substrate lies in the range from 30:1 to 1:10 and

(c) a surfactant system comprising an alkoxylated nonionic surfactant having an HLB in the range 8.0-17.0 and a cationic surfactant having the empirical formula -
R¹_mR²_xY_L^Z
wherein R¹ is a hydrophobic organic radical containing alkyl chains, and/or aryl groups and which may also contain ether linkages, ester linkages, or amide linkages and containing a total of from 8 to 20 carbon atoms, m is a number from one to three, and-no more than one R¹ can have more than 16 carbon atoms when m is 2, or more than 12 carbon atoms when m is 3, R² is a substituted or unsubstituted alkyl group containing from one to four carbon atoms or a benzyl group provided that not more than one such benzyl group is directly attached to each Y group, x is a number from zero to three, the remainder of any carbon atom positions being filled by hydrogens, Y is selected from the group consisting of







L is a number from 1 to 4, Z is a water-soluble anion in a number to give electrical neutrality, the cationic surfactant being water dispersible in admixture with the nonionic surfactant, the weight ratio of the nonionic surfactant to the cationic surfactant being in the range 20:1 to 1:2, the weight ratio of the surfactant system to the substrate being in the range 20:1 to 1:5.

[0005] As used herein, an organic peroxy compound precursor is any.organic compound capable of reaction with an inorganic peroxygen-containing compound in aqueous solution to give an organic peroxy compound having a bleaching performance at a temperature of 70⁰C and below, at least equivalent to that of the inorganic peroxygen containing compound under the same conditions.

[0006] Also as used herein, the terms inorganic peroxy bleach and inorganic pcrsalt arc intended to cover such salts as alkali metal perborates, percarbonates, persilicates and perpyrophosphates which produce hydrogen peroxide in aqueous solution rather than compounds such as persulphates and permanganates which produce other peroxy species.'

[0007] In a preferred aspect of the present invention, the cationic-nonionic surfactant mixture comprises a · mono-C₁₂C₁₄ alkyl, tri- C₂-C₄ alkyl quaternary ammonium salt, particularly the chlonide or the methosulphate, and an ethoxylated linear C₂₄-C₂₃ primary alcohol containing an average of from 'about 5 to about 30 moles of ethylene oxide per mole of alcohol, the weight ratio of the nonionic to the cationic surfactant being in the range 5:1 to 3:2.

[0008] In a further preferred aspect of the invention, the organic peroxy compound precursor or each of the components of a mixture of such precursors is selected from the group consisting of anhydrides, esters, oximes and N-acylated compounds. Preferably the precursor is one or more N-acetylated compounds of structure:

where x can be O or any integer between 1 and 6 and is most preferably O, 2 or 6.

[0009] Preferably the substrate is in the form of a flexible sheet wherein the weight ratio of the precursor to the substrate lies in the range 10:1 to 1:10_.

[0010] In a method aspect of the invention, a method of making a laundry additive product comprises the steps of forming the nonionic-cationic surfactant system and the peroxy compound precursor into a fluid mass, impregnating a solid non-particulate water permeable article with said mass and causing said mass to solidify.

[0011] Preferably the combination of the surfactant system and the precursor is mixed with a solid non-hygroscopic organic adjuvant to provide a melt having a viscosity of up to 5000 centipoises at 50οC, this melt constituting a fluid mass with which the substrate is impregnated.

[0012] The additive produchs of the invention are designed to be introduced into the washing machine with the soiled fabrles, or at the boaimning of the wash cycle in pro- grammod drum machines,
In accordance with the invention disclosed in Swedish Patent Application No. 7711151-G, the precursor or mixture thereof is normally added in a separate product to that containing the inorganic peroxygen-containing compound although, as described hereinafter, the precursor and the peroxygen-containing compound can be incorporated on a single substrate provided they are physically separated from each other.

[0013] Thus, the precursor or mixture of precursors and the inorganic peroxy bleach do not come into contact with each other except in the washing liquor. The delivery of the precursor mixture to the wash liquor in water-releasable combination with a non-particulate solid article avoids most of the stability problems encountered in prior art products and also permits control by the user of whether or not low temperature bleaching is to be employed and the level of bleaching that is to be used. The additive products of the present invention also enhance the human safety of low temperature bleaching of domestic laundry by materially increasing the difficulty of accidental ingestion of the combination, of the combination.

[0014] The products of the present invention also provide an enhanced rate of release for the peroxy compound precursors into the wash liquor relative to that achieved from prior art granular products and this, in turn, improves the rate of conversion into the organic peroxy bleaching species. The disinfectant efficiency of the organic perox^y compounds is thereby improved and the harmful effects of catalase on the bleaching capability of residual inorganic peroxy bleach are reduced.

THE ORGANIC PEROXY COMPOUND PRECURSOR

[0015] Organic peroxy compound precursors, or inorganic persalt activators, as they are usually known, are well known in the art and are described extensively in the literature.

[0016] In the broadest aspect of the invention, any of the organic peroxy compound precursors described in the above mentioned Swedish Patent Application No 7711151-6 can be employed cither ainglyor in combination, but it has been found that where the pmecursor or mixture of precursors comprises perbenzoic acid generating compounds, combinations thereof with at least one peracetic acid-generating compound in a weight ratic of from 5:1 to 1:5 provide an optimum balance of bleaching and colour safety characteristics.

[0017] Thus anhydrides, eiters, cnrbonates, acylated oximes, chloroformates and cyano cempounds are all useful classes of organic peroxy compound precursors. N-acylated compounds are also useful, typical examples being the imide, imidazole, sulphonamide and triazine classes and certain acylated hydrazines. Preferred classes of materials are the anhydrides, esters, acylated oximes, imides and acylated hydrazines.

[0018] Particularly preferred compounds are N,N,N',N'-tetra acetylated compounds of formula

in which x can be O or an integer between 1 and 6. Where x is an integer between. 1 and 6, the compounds are imides, examples being tetraacetyl methylene diamine (TAMD) where x=l, tetra-acetyl ethylene dianine (TAED) where x=2, and tetraacetyl hexamethylene diamine (TAHD) where x=6. Where x=O the compound is tetraacotyl hydrazine (TAH). TAHD and TAH arc particularly preferred because of their low melting points (59°C and 83°C respectively) which facilitates their processing in additive products of the present invention as described hereinafter. All of these compounds and the process for making them are described in British Patent Specification No. 907,856 the disclosures of which are specifically ineorporamed herein by reference.

[0019] The amernt be the pordxy compound precursor or precursor mixture applied be the substrate is arranged such that. the prccursorsor:subsbrale raude is within the range 30:1 to 1:10 preferably 8:1 to 1:4 and most preferably 5:1 to 1:2 by weight.

[0020] The level of usage of organic peroxy compound precursor will naturally be dependent on a number of factors eg. the size of the fabric load in the machine, the level of bleaching performance desired, the amount of inorganic persalt in the conventional detergent products and the usage of the detergent product, the bleaching efficacy of the organic peroxy species derived from the precursor and the efficiency of conversion of the precursor into that peroxy species. It is conventional with inorganic peroxy bleaches to provide a level of available oxygen in solution of from 50 ppm to 350 ppm by weight for heavy duty laundry purposes. However, when using organic peroxy bleaches a level or available oxygen provided by the organic peroxy compound should be in the range 10 ppm to 80 ppm. This level of available oxygen should be attained within the normal wash cycle time ie. within 15 to 25 minutes depending on the particular wash cycle being employed.

[0021] For a machine having a liquid capacity in use of 20. to 30 litres, such a level of available oxygen requires the delivery of from 1 gr to 20 gr of organic peroxy compound precursor assuming quantitive conversion. This figure will increase proportionately with any decrease in the efficiency of conversion. Preferably a single unit of substrate should be capable of accommodating this level of precursor and any adjuvants and additives that it is necessary to incorporate into the product although the number of units to be used to deliver a given quantity of precursor is a matter of choice. Normally the weight of precursor per delivery will lie in the range 3 to 10 grs.

THE NONIONIC-CATIONIC SURFACTANT MIXTURE

[0022] The grease and oil removal component of the present invention comprises a mixture of a water-soluble, cationic surfactant and an alkoxylated nonionic surfactant of defined HLB range, the weight ratio of the two surfactants being within the range 20:1 t6 1:2, preferably 10:1 to 1:1, and most preferably 5:1 to 3:2. The nonionic surfactants used in the compositions may be alkoxylated aliphatic alcohols, alkyl phenols, esters, anudes and fatty acids having an HLB within the range 8.0-17.0. The aliphatic alcohols include linear and branched chain primary and secondary C₈-C₂₂ alcohols, the alkyl phenols are the C₆-C₁₂ alkyl phenols, and the fatty esters, fatty amides and fatty acids are those having a C₁₂-C₁₈ alkyl group in the acyl residue. The preferred alkoxylating group is ethylene oxide.

[0023] Suitable nonionic surfactants based on aliphatic alcohols are condensation products of primary and secondary alcohols with from about 4 to about 30 moles of ethylene oxide. The alkyl chain of the aliphatic alcohol can either be straight or branched and generally contains from about 8 to about 22 carbon atoms. Examples of such ethoxylated alcohols include the condensation product of myristyl alcohol with about 10 moles of ethylene oxide per mole of alcohol and the condensation product of about 9 moles of ethylene oxide with coconut alcohol (a mixture of fatty alcohols with alkyl chains varying in length from 10 to 14 carbon atoms). Examples of commercially available nonionic surfactants of this type include Tergitol 15-S-9, marketed by Union Carbide Corporation, Dobanol 45E9, marketed by Shell Chemical Company, and kyro EO, marketed by The Procter & Gamble Company. Other suitable alcohol ethoxylates include:-

Tallow (C₁₆-C₁₈) alcohol (E₂₅)

Linear (C₁₄-C₁₅) alcohol (E₅) (C₁₄-C₁₅) aleohol (E₇) (C₁₂ C₁₃)slcohol (E₆) (C₉-C₁₁) alcohol (E₅)

Branched (C₁₀-C₁₃) alcohol (E₄)

Linear (s-C₁₁-C₁₅) alcohol (E₅) (s-C₁₁-C₁₅) alcohol (E₇) (S-C₁₁-C₁₅) alcohol (E₉) ___

[0024] Alcohol cthoxylatcs'such as those disclosed in British Patent Specification No. 1,462,134, incorporated herein by reference, are also useful in the present invention.

[0025] Suitable alkyl phenol ethoxylates include the condensation products of alkyl phenols having an alkyl group containing from about 6 to about 12 carbon atoms in either a straight chain or branched chain configuration with ethylene oxide, said ethylene oxide being present in an amount equal to 8 to 20 moles of ethylene oxide per mole of alkyl phenek. The alkyl substituent in such compounds can be derived, ter

[0026] Suitable fatty acid ethoxylates include coconut ratty acid (E₅) and oleic fatty acid (E₁₀), while ecter ethexy- lates include:

Other nonionic surfactants useful

condensation promets of ethylene

resulting from the condensation of propylene oxide with propylene glycol. Surfactants of this type are available commerically from the xyandotte Chemicals Corporation under the names "Tetronic" and "Pluronic" respectively.

[0027] Particularly preferred materials are the primary linear and branched chain primary alcohol ethoxylates, such as C₁₄-C₁₅ linear alcohols condensed with 7-15 moles of ethylene oxide available from Shell Oil Company under the "Dobanol" Trade Mark and the C₁₀-C₁₃ branched chain alcohol ethoxylates obtainable from Liquichimica SA under' the 'Lial' Trade Mark.

[0028] The cationic surfactants used in the compositions of the present invention have the empirical formula -

wherein each R¹ is a hydrophobic organic group containing alkyl chains, alkenyl chains, alkyl benzyl chains, alkyl phenyl chains, ether linkages,alkylene groups, alkenylene groups, ester linkages, and amide linkages totalling from about 8 to 20 carbon atoms and which may additionally contain or be attached to a polyethylene oxide chain containing up to about 20 ethoxy groups, and m is a number from one to three. No more than one R¹ in a molecule can have more than 16 carbon atoms when m is 2 and no more than 12 carbon atoms when m is 3. R² is an alkyl or hydroxyalkyl group containing from 1 to 4 carbon atoms or a benzyl group with no more than one R² in a molecule being benzyl, and x is a number from 0 to 3. The remainder of any carbon atom positions on the Y group are filled by hydrogens. Y is selected from the group consisting of:







L is a number from 1 to 4, and Z is a water-soluble arion, such as halide, methylsulfate, hydroxide, or nitrate anion, particularly preferred being chloride, bromide or ledide anions, in a number to give electrical neutrality of the cationic component. The particular cationic component to be included in a given system depends to a large extent upon the particular nonionic component to be used in this system, and is selected such that it is at least water-dispersible, or preferably water-soluble, when mixed with said nonionic surfactant. It is preferred that the cationic component be substantially free of hydrazinium groups. Mixtures of these cationic materials may also be used in the compositions of the present invention.

[0029] When used in combination with nonionic surfactants, these cationic components provide excellent soil removal characteristics, confer static control and fabric softening benefits to the laundered fabrics, and inhibit the transfer of dyes among the laundered fabrics in the wash solution.

[0030] In preferred cationic materials, E is equal to and Y is :

[0031] However, L may be greater than 1, such as in cationic components containing 2 or 3 cationic charge centers. Other cationic materials which are useful in the compositions of the present invention include phosphonium, sulfonium, and imidazolinium materials.

[0032] Wherein Y is

and m = 1 it is preferred that x is equal to 3. R² is typically C₁-C₄ alkyl, hydroxyalkyl or benzyl(no more than one benzyl group being permissible) but is usually a methyl group. A preferred structure is where one R² group is hydroxyethyl. Cationic surfactants of this mono long chain type include those in which R¹ is a C₁₀-C₂₀ alkyl group more preferably a C₁₀-C₁₆ alkyl group or a C₁₀-C₁₅ alkylbenzyl group. Particularly preferred compositions of this class include C₁₂ alkyl trimethyl ammonium bromide, C₁₂ alkyl dimethyl hydroxyethyl ammonium bromide, C₁₂ alkyl dimethyl hydroxypropyl ammonium bromide, C₁₂ alkyl dimethylbenzyl ammonium chloride and their counterparts based on middlecut coconut alcohol as the source of the alkyl group. Other counter ions such as methosulphate , sulphate, sulphonate and carboxylate can also be used particularly with the hydroxyalkyl- substituted compounds.

[0033] Specific examples of hydroxyalkyl substituted compounds are the C₁₀-C₁₆ dimethyl hydroxyethyl ammonium lauratcs, palmitaees, cleates and stearates. These compounds have a waxy physical form and are relatively non- hygroscopic, thereby faeilitating their incorporation into the additive products of the invention.

[0034] Where m is eequal to 2, only one of the R¹ chains can be longer than 16 carbo. atoms. 'Thus ditallowdimethyl- ammonium chloride and distearyldimethylammonium chloride, which are used conventionally as fabric softeners and static control agents in detergent compositions, may not be used as the cationic component in the surfactant

of the present invention. Preferred di-long chain catiemoes of this type include those in which x.is equal to 2 and R² is a methyl group. In this instance it is also preferred that R¹ is a C₈ to C₁₂ alkyl group. Particularly preferred cationic materials of this class include di-C₈ alkyldimetnyl- ammonium halide and di-C₁₀ alkyldimethylammonium halide materials.

[0035] Where m is equal to 3, only one of the R¹ chains can be greater than 12 carbon atoms in length. The reason for this chain length restriction, as is also the case with the di-long chain cationics described above,is the relative insolubility of these tri- and di-long chain materials. Where tri-long chain alkyl materials are used, it is preferred that R² is a methyl group. In these compositions it is preferred that R¹ is a C₈ to C₁₁ alkyl group. Par ticularly preferred tri-long chain cationics induce cri- octylmethylammonium halide, and tridecylmethylammonlum halide.

[0036] Cationic surfactants of this type can be preporea oy techniques well known to those skilled in the art and which do not form part of the present invention. However a particularly preferred technique
comprises the quaternisation of a tertiary amine in a liquid polyethylene oxide condensate reaction medium which is itself a component of the present invention. The resistant mixture of a cationic surfactant and a polyethylene oside condcnsatc can be applied directly to the substrate without isolatien of the cationic surfactant per se.

[0037] The technique involves dissolving or dispering a normally non-volatile tertiary amine, coptaining one or more long chain hydroearbon residues,

ethoxylate oondensate. A relatively volatile quaternising agent having a boiling point less than 200°C, preferably less than 100°C_' and most preferably less than ambient temperature, is reacted with this mixture to form the cationic surfactant. The mixture of cationic surfactant and ethoxylate is normally a dispersion which is solid at ambient temperatures and liquid at temperatures greater than approximately 45°C but certain preferred hydroxyalkyl group containing quaternary ammonium surfactants having a long chain carboxylate counter ion are miscible with polyethoxylated nonionic surfactants and form clear solutions.

[0038] Specific examples of these preferred quaternary ammonium surfactants are myristyl dimethyl hydroxyethyl ammonium stearate, lauryl dimethyl hydroxyethyl ammonium palmitate, and lauryl dimethyl hydroxyethyl ammonium oleate. These compounds are non-crystalline low melting solids having acceptable water solubility together with low hydroscopicity and provide, in combination with nonionic surfactants, enhanced grease and oily stain removal.

[0039] Because of their waxy nature and their high affinity for conventional solvents these hydroxyalkyl group-containing quaternary ammonium surfactants are very difficult to prepare in the solvent-free solid state and the above-described technique is a convenient way to obtain them in a form suitable for the purposes of the present invention.

[0040] Another useful type of cationic component has the formula

wherein R¹ is C₁ to C₄ alkyl or hydroxyalkyl; R² is C₅ to C₃₀ straight or branched chain alkyl or alkenyl, Alkyl benzene, or

R³ is C₁ to C₂₀ alkyl or alkcnyl; a is O or 1; n is O or 1; m is from 1 to 5; Z¹ and Z² are each selected from the group consisting of

and wherein at least one of said groups is selected from the group consisting of ester, reverse ester, amide and reverse amide; and X is an anion which makes the compound at least water-dispersible, preferably selected from the group consisting of halide, methylsulfate, hydroxide, and nitrate preferably chloride, bromide or iodide.

[0041] Particularly preferred cationic

type are the choline ester derivatives

formula



well

formula

amide linkage.

[0042] Particularly preterred examples of this type of cationic surfactant include stearoyl choline ester quaternary ammonium halides (R² = C₁₇ alkyl), palmitoyl choline ester quaternary ammonium halides (R² = C₁₆ alkyl), myrist- oyl choline ester quaternary ammonium halides (R2 = C₁₃ alkyl), lauroyl choline ester ammonium halides (R² = C₁₁ alkyl), and tallowoyl choline ester quaternary ammonium halides (R² = C₁₆-C₁₈ alkyl).

[0043] Additional preferred cationic components of the choline ester variety are given by the structural formulas below, wherein p may be from O to 20.

[0044] The preferred choline-derivative cationic substances, discussed above, may be prepared by the direct esterification of a fatty acid of the desired chain length with dimethylaminoethanol, in the presence of an acid catalyst. the reaction product is then quaternized with a methyl halide, forming the desired cationic material. The choline- derived cationic materials may also be prepared by the direct esterification of a long chain fatty acid of the desired chain length together with 2-haloethanol, in the presence of an acid catalyst material. The reaction product is then used to quaternize triethanolamine, forming the desired cationic component.

[0045] Another type of novel, particularly preferred cationic material has the formula

In the above formula, each R¹ is a C₁ to C₄ alkyl or hydrexy- alkyl group, preferably a methyl group. Each R² is either hydrogen or C₁ to C₃ alkyl, preferably hydrogen. R³ is a C₄ to C₃₀ straight or branched chain alkyl, alkenylene, or alkyl benzyl group, preferably a C₈ to C₁₈ alkyl group, most preferably a C₁₂ alkyl group. R is a C₁ to C₁₀ alkylene or alkenylene group. n is from 2 to 4, preferably 2; y is from 1 to 20, preferably from about 1 to 10= most preferably about 7; a may be O or 1; t may be 0 or 1; and m is from 1 to 5, preferably 2. Z¹ and Z² are each selected from the group consisting of

and wherein at least one of said groups is selected from the group consisting of ester, reverse ester, amide and reverse amide. X is an anion which will make the compou at least water-dispersible, and is selected from the 9 consisting of halides, methylsulfate, hydroxide and moera re. particularly chloride bromide and iodide.

[0046] These novel cationic surfactants may be used in nonionic/cationic surfactant mixtures in a ratio of nonionic component to cationic component of from about 10;6 to about 20:1. When these surfactants are used in the compositions of the present invention they are used in nonionic to cationic ratios of from about 10:6 to about 10:2.

[0047] These surfactants, when used in the compositing of the present invention, yield excellent partiuclate soil, body soil, and grease and oil soil removal. In addition the detergent compositions control static and soften the fabrics laundered therewith, and inhibit the transfer of dyes in the washing solution. Further, these novel cationic surfactants are environmentally desirable, since both their long chain alkyl segments and their nitrogen segments are biodegradable.

[0048] Preferred embodiments of this type of cationic component are the choline esters (R¹ is a methyl group and Z² is an ester or reverse ester group), particular formulas of which are given below.

[0049] The preferred choline derivatives, described above, may be prepared by the reaction of a long chain alkyl poly- alkoxy (preferably polyethoxy) carboxylate, having an alkyl chain of desired length, with oxalyl chloride, to form the corresponding acid chloride. The acid chloride is then reacted with dimethylaminoethanol to form the appropriate amine ester, which is the ^quaternized with a methyl halide to form the desired choline ester compound. Another wav of preparing these compounds is by the direct esterification of the appropriate long chain ethoxylated carboxylic. acid together with 2-haloethanol or dimethyl aminosthanol, in the presence of heat and an acid catalyse. The reaction formed is then quaternized with methylhalide or used to quaternized trimethylamine to form the desired choline ester compound.

[0050] The amount of the nonionic-cationic mixture is such that the surfactant mixture:substrate weight ratio lies in the range 20:1 to 1:5, preferably from 10:1 to 1:2, and most preferably from 8:1 to 1:1. In preferred exsor- tions using non-woven sheet substrates of approximately 100 sq. ins. plan area and ≃ 3 grs./sheet basis weight, the loading of nonionic-cationic surfactent mixture is in the range 4-15 grs./sheet.

[0051] Where the nonionic-cationic surfactant mixture is liquid at normal temperatures, its physical incorporation can take place in a number of ways. Where the substrate

non-hygroscopic material of higher melting point to provide a waxy solid in which the surfactant is present in the form of a solid solution and/or as a dispersed phase. The melting point range and waxy nature of polyethylene glycols of molecular weight > 4000 make them useful for this purpose, although their hygroscopicity under extreme conditions of humidity leads to high levels of'moisture pick-up if appreciable amounts of such glycols are used. Other useful materials include C₁₂-C₁₈ fatty acid alkanolamides. However, the preferred materials are the higher fatty acids, particularly the C₁₆-C₁₈ saturated fatty acids which are employed in an amount such that the weight ratio of fatty acid to nonionic-cationic surfactant mixture is in the range 1:5 to 4:1, preferably 1:3 to 3:2 and most preferably 2:3 to 1:1.

[0052] Where the surfactant mixture is a solid at normal temperature but is molten at a temperature less than about 100°C preferably less than about 80°C, the surfactant mixture itself can be used as the vehicle for incorporating other non liquid components into the substrate. Surfactant mixtures in which the nonionic is a high ethoxylate such as Tallow alcohol (E₂₅₎ and C₁₄-C₁₅ primary alcohol (E₁₅) are examples'of this type.

[0053] Highly preferred surfactant mixtures are those produced by the technique of cationic surfactant formation in the ethoxylated nonionic surfactant described hereinbefore.

SUBSTRATE

[0054] The present invention requires that the peroxy compound precursor be in water-releasable combination with a substrate comprising a non-particulate solid article. The substrate may itself be water soluble or water insoluble and in the latter case it should possess sufficient structural integrity under the conditions of the wash to be recovered from the machine at the end of the laundry cycle. Structures which are water disintegratable ie. that break down in aqueous media to individual fibres or insoluble particles are not considered satisfactory for the purposes of the present invention.

[0055] Water soluble materials include certain cellulose ethers, alginates, polyvinyl alcohol and water soluble polyvinyl pyrrolidone polymers, which can be formed into non-woven and woven fibrous structures. Suitable water insoluble materials include, but are not restricted to, natural and synthetic fibres, foams, sponges and films.

[0056] The substrate may have any one of a number of physical forms such as sheets, blocks, rings, balls, rods or tubes. Such forms should be amenable to unit usage by the consumer, ie. they should be capable of addition to the washing liquor in measured amounts, such as individual sheets, blocks or balls and unit lengths of rods or tubes. Certain of these substrate types can also be adapted for single or multiple uses, and can be provided with loadings of organic peroxy acid precursor up to a precursor:substrate ratio of 30:1 by weight.

[0057] One such article comprises a sponge material releasably enclosing enough organic peroxy compound precursor to provide bleaching action during several washing cycles. This multi-use article can be made by impregnating a sponge ball or block with about 20 grams of the precursor and anv adjuncts therewith. In use, the precursor leaches out through the pores of the sponge into the wash liquor and reacts with the inorganic peroxy bleach. Such a filled sponge can be used to treat several loads of fabrics in conventional washing machines, and-has the advantage that it can remain in the washer after use.

[0058] Other devices and articles that can be adapted for use in dispensing the organic peroxy compound precursor in a washing liquor include those described in Dillarstone, U.S. Patent 3736668, issued 5 June, 1973: Compa et al, U.S. Patent 3701202, issued 31 October, 1972: Purgal, U.S. Patent 3634947, issued 18 January, 1972: Hoeflin, U.S.. Patent 3633538, issued 11 January, 1972 and Rumsey, U.S. Patent 345537, issued 1 April, 1969. All of these patents are incorporated herein by reference.

[0059] A highly preferred article herein comprises the organic pcroxy compound precursor in water-releasable combination with a sheet and this should be flexible so as to make it compatible with the movement of the fabrics in the washing machine and to facilitate its handling during manufacture of the product. Preferably the sheet is water pervious i.e. water can pass from one surface of the sheet to the opposite surface and, for film type substrates, perforation of the sheet is desirable. The most preferred form of the substrate is a sheet of woven or non-woven fabric or a thin sheet of cellular plastic material. Woven fabric sheets can take the form of a plain weave natural or synthetic fibre of low fibre count/unit length, such as is used for surgical dressings, or of the type known as cheese cloth. Loading limitations on non-woven sheet type substrates limit the amount of precursor that can be applied to the sheet, namely to a maximum required by the precursor: sheet weight ratio of about 10:1.

[0060] A desirable feature of a substrate to be utilised in the present invention herein is that it be absorbent in nature. It is known that most substances are able to absorb a liquid substance to some degree; however, the term "absorbent", as used herein, is intended to mean a substance with an absorbent capacity (ie. values representing a substrate's ability to take up and retain a liquid) of up to approximately 12 times its weight of water.

[0061] Determination of absorbent capacity values is made by using the capacity testing procedures described in U.S. Federal Specification UU-T595b modified as follows:

1. tap water is used instead of distilled water;

2. the specimen is immersed for 30 seconds instead of 3 minutes;

3. draining time is 15 seconds instead of 1 minute; and

4. the specimen is immediately weighed on a torsion balance having a pan with turned-up edges.

[0062] Absorbent capacity values are then calculated in accordance with the formula given in said specification. Based on this test, one-ply, dense, bleached paper (eg. kraft or bond having a basis weight of about 32 pounds per 3,000 square feet, has an absorbent capacity of 3.5 to 4; commercially available household one-ply towelling paper has a value of 5 to 6; and commercially available two-ply household towelling paper (a paper structure preferred herein) has a value of 7 to about 9_'.5.

[0063] The substrate of this invention can also be defined in terms of "free space". Free space, also called "void volume", as used herein is intended to mean that space within a structure that is unoccupied. For example, certain multi-ply paper structures comprise plies embossed with protuberances, the ends of which are mated and jointed; such a paper structure has a void volume of free space between the unembossed portion of the plies, as well as between the fibres of the paper sheet itself. A non-woven cloth also had such space between each of its fibres. The free space of non-woven cloth or paper, having designated physical dimensions, can be varied by modifying the density of the fibres of the paper or non-woven cloth. Substances with a high amount of free space generally have low fibre density, high density substrates generally have a low amount of free space. Preferred substrates of the invention herein have up to about 90% free space based on the overall voluma of the substrate's structure.

[0064] As stated above, suitable materials

as a substrate in the invention herein

others, sponges, paper, and woven and

[0065] A preferred paper substrate is a compressible, laminated, calendered, multi-ply absorbent paper structure. Preferably, the paper strcoure has 2 or 3 plies and a total basis weight of from 14 to 90 pounds per 3,000 square feet and absorbent capacity values within the range of 7 to 10. Each ply of the preferred paper struoture has a basis weight of about 7 to 30 pounds,

feet, and the paper structure can

the same or different basis weights.

ably made from creped, or otherwise extensible, paper with crepe percentage of ahout 15% to 40% and a machine direction (MD) tensile and cross-machine (CD) tensile of from about 100 to 1,500 grams per square inch of paper width. The two outer plies of a 3-ply paper structure or each ply of a 2-ply paper structure are embossed with identical repeating patterns consisting of about 16 to 20QO discrete protuberances per square inch, raised to a height of from about 0.010 inch to 0.40 inch above the surface of the unembossed paper sheet. From about 10% to 60% of the paper sheet surface is raised. The distal ends (ie. the ends away from the unembossed paper sheet surface) of the protuberances on each ply are mated and adhesively joined together, thereby providing a preferred paper structure exhibiting a compressive modulus of from about 200 to 800 inch-grams per cubic inch and Handle-O-Meter (HOM) MD and CD values of from about 10 to 130.

[0066] The compressive modulus values which define the compressive deformation characteristics of a paper structure compressively loaded on its opposing surfaces, the HOM values which refer to the stiffness or handle of a paper structure, the MD and CD HOM values which refer to HOM values obtained from paper structure samples tested in a machine and cross-machine direction, the methods of determining these values, the equipment used, and a more detailed disclosure of the paper structure preferred herein, as well as methods of its preparation, can be found in Edward R. Wells, US Patent No. 3,414,459, issued on 3rd December, 1968, the full disclosure of which is hereby incorporated hereinto.

[0067] The preferred non-woven cloth substrates usable in the invention herein can generally be defined as adhesively bonded fibrous or filamentous products, having a web or carded fibre structure (where the fibre strength is suitable to allow carding) or comprising fibrous mats, in which the fibres or filaments are distributed haphazardly or in random array (ie. an array of fibres in a carded web wherein partial orientation of the fibres is frequently present

distrubitonal orientation) or substantially aligned. The fibres of filaments can be natural (eg, wool, silk, jute, hemp, cotton,

or synthetic (eg. rayon, cellulose, or polyesters).

[0068] Methods of making non-woven cloths are not a part of this invention and being well known in the art, are not described in detail herein. Generally, such cloths are made by air or water laying processes in which the fibres or filaments are first cut to desired lengths from long strands, passed into a water or air stream, and then deposited onto a screen through which the. fibre-laden air or water is passed. The deposited fibres or filaments are then adhesively bonded together, dried, cured and otherwise treated as desired to form the non-woven cloth. Non-woven cloths made of polyesters, polyamides, vinyl resins, and other thermoplastic fibres can be spunbonded, i.e. the fibres are spun out onto a flat-surface and bonded (melted) together by heat or by chemical reactions.

[0069] The absorbent properties desired herein are

easy to obtain with non-woven cloths and are provided nerely by building up the thickness of the cloth, ie. by superimposing a plurality cf carded webs or mats to a thickness adequate to obtain the necessary absorbent properties. or by allowing a sufficient thickness of the fibres to deposit on the screen. Any diameter or denier of the fibre (generally up to about 10 denier) can be used. inasmuch as it is the free space between each fibre that makes the thickness of the cloth directl" related to the absorbent capacity of the cloth, and which further makes the non-woven cloth espcically suitable for impregnation with a peroxy compound procursor by means of intersectional or capillary action. Thus, any thickness necessary to obtain the required absorbent capocity can be used.

[0070] The choice of pinder-resins used in the manufacture of non-woven clothe can provide substrates possessing a

regulated by respectively using a hydrophilic binder-resin,a hydrophobic binder-resin or a mixture thereof in the fibre bonding step. Moreover, the hydrophobic binder-resin, when used singly or as the predominant compound of a hydrophobic-hydrophilic mixture, provides non-woven cloths which are especially useful as substrates when the precursor substrate combinations disclosed herein are used in an automatic washer.

[0071] When the substrate herein is a non-woven cloth made from fibres, deposited haphazardly or in random array on the screen, the compositions exhibit excellent strength in all directions and are not prone to tear or separate when used in the washer. Apertured non-woven substrates are also useful for the purposes of the present invention. The apertures, which extend between opposite surfaces of the substrate are normally in a pattern and are formed during laydown of the fibres to produce the substrate. Exemplary apertured non-woven substrates are disclosed in US Patent Nos. 3,741,724, 3,930,086 and 3,750,237, the disclosures of which are specifically incorporated herein by reference.

[0072] Preferably, the non-woven cloth is water-laid or air-laid and is made from cellulosic fibres, particularly from regenerated cellulose or rayon, which are lubricated with standard textile lubricant. Preferably, the fibres are from 3/16" to 2" in length and are from 1.5 .to 5 denier (Denier is an internationally recognised unit in yarn meausrc, corresponding to the weight in grams of a 9,000 meter length of yarn). Preferably, the fibres are at least partially orientated haphazardly, particularly substantially haphazardly, and are adhesively bonded together with hydrophobic or substantially hydrophobic binder-resin, particularly with a nonionic self-crosslinking acrylic polymer or polymers. Conveniently, the cloth comprises about 70% fibre and 30% binder-resin polymer by weight and has a basis weight of from 10 to about 100, preferably 20 to GO grammes per square yard.

[0073] A particularly preferred example is an air-laid non-woven cloth comprising 70% regenerated cellulose (American Viscose Corporation) and 30% hydrophobic binder-resins (Rhoplex HA-8 on one side of the cloth, Rhoplex HA-16 on the other; Rohm & Haas, Inc.). The cloth has a thickness of 4 to 5 mils., a basis weight of about 24 grams per square yard, and an absorbent capacity of 6. One foot length of the cloth 8 1/3" wide, weighs about 1.78 grams. The fibres are 1/4 in length, 1.5 denier and are orientated substantially haphazardly. The fibres are lubricated with sodium oleate.

[0074] A further preferred substrate is a water-laid, non-woven cloth commerically available from C.H. Dexter Co. Inc. The fibres are regenerated cellulose, about ⅜" in length, about 1.5 denier, and are lubricated with a similar standard textile.lubricant. The fibres comprise about 70% of the non-woven cloth by weight and are orientated substantially haphazardly; the binder-resin (HA-8) comprise about 30% by weight of the cloth. The substrate is about 4 mils. thick, and it has a basis weight of about 24 grams per square yard and an absorbent capacity of 5.7. One foot length of the cloth, 8 1/3" wide, weights about 1.66 grams.

[0075] A further class of substrate material that can be used in the present invention comprises an absorbent foam like material in the form of a sheet. The term 'absorbent foam- like material' is intended to encompass three dimensional absorptive materials such as 'gas-blown foams', natural sponges and composite fibrous based structures such as are disclosed in US Patent Nos. 3311115 and 3430630 specifically incorporated herein by reference. Synthetic organic polymeric plastics material such as polyether, polyurethane, polyester, polystyrene, polyvinylchloride, nylon, polyethylene and polypropylene are most often employed and a particularly preferred material of this type is a hydrophilic polyurethane foam in which the internal cellular walls of the foam have been broken by reticulation. Foams of this type are described in detail in Dulle US Patent No. 3794029 which is hereby specifically incorporated by reference, A preferred example of this foam type comprises a hydrophilic polyurethane foam of density about 0.596 grs. per cubic inch with a cell count of between 20 and 100 cells per inch, preferably about 60 to 80 per inch available from the Scott Paper Company, Eddystone, Pennsylvania USA, under the Registered Trade Mark "Hydrofoam'' .

[0076] The size and shape of the substrate sheet is a matter of choice and is determined principally by factors associated with the convenience of its use. Thus the sheet should not be so small as to become trapped in the crevices of the machine or the clothes being washed or so large as to be awkward to package and dispense from the container in which it is sold. For the purposes of the present invention sheets ranging in plan area from 20 square inches to 200 square inches are acceptable, the preferred area lying the range of from 80 to 160 square inches for non-woven substrates and 30 to 30 square inches for foamed sheets. Such a size has the additional advantage of being too large to be swallowed by eg. small children, thereby minimising the risk of internal tissue damage from ingestion of the materials absorbed on the substrate.

OPTIONAL COMPONENTS

[0077] In adaition to the peroxy compound precursors, one or more other materials can be applied to the substrate either separately or together with the precursors, the only constraint on such materials being that the amount that can be incorporated is restricted because of the loading limitations of the substrate. For the substrate types preferred in the present invention the weight of optional component per sheet is unlixcly to be more than 10 times the sheet weight, and preferably is less than 5 times the sheet weight and oreferably is less than 5 times the sheet weight.

[0078] The principal optional components are solid water soluble or

organic adjuvants. These adjuvants can fulfill a variety of functions in the product, such as processing and release aids, specific additives providing performance improvement in the wash cycle and aesthetic ingredients.

[0079] One major ingredient can be a processing aid which serves as a plasticiser or thickener in the incorporation of the precursors into or onto the substrate. However, in certain preferred compositions of the present invention, the cationic-nonionic surfactant mixture itself serves as a processing aid as hereinbefore described, and thus little or no additional processing aid is required. Certain other preferred cationic-nonionic mixtures, particularly those wherein the alkoxylated nonionic product is of low HLB, require the use of a thickening adjuvant as described hereinbefore. These adjuvants are solids that are mixed with the precursors and melted to provide.mixtures having a viscosity of up to 5000 centipoises at 50°C. Typical solids are polyvinyl pyrrolidone of M.Wt. 44,000 - 700,000. preferably 500,000 - 700,000 tallow alcohol ethoxylates containing from 5 to 30 ethylene oxide groups, C₁₂ -C₁₈ fatty acids and certain amides and esters thereof, sorbitan esters of C₁₆ -C₁₈ fatty acids and polyethylene glycols of molecular weight greater than 4,000. As stated hereinbefore, preferred adjuvants are those having low hygroscopicity such as the ^C₁₆ -^C₁₈ saturated fatty acids.

[0080] Certain compounds which are themselves ^peroxy compound precursors, such as methyl o-acetoxy benzoate, polyazelaic polyanhydride of M.Wt. 1,000 - 2,000 and succinic acid dinitrile, have the required characteristics for use as processing aids and can be employed as such. Paraffin waxes can also be used in minor amounts. Where the processing aid does not have any other function in the product, such as a surfactant component of the grease- removal surfactant mixture, its level of incorporation will be such that the precursor:processing aid weight ratio will be in the range from 20:1 to 1:3, the latter value being for economic reasons. However, the weight ration of precursor:processing aid can be as low as 1:10 where the processing aid has other functional properties such as surfactancy. A further class of materials useful as a processing aid are the polyacrylamides of molecular weight ≈500,000 which are thixotropic water soluble polymers that can retain water in the solid state. The organic peroxy compound precursor can be dissolved or dispersed in an aqueous mull of the polymer. The mull is then fed to the substrate web and deposited to impregnate/ coat the substrate whereupon it sets as a solid, but water soluble, gel. This particular class of materials is especially valuable for applying the organic peroxy compound precursors to water soluble substrates such as polyvinyl alcohols which tend to lose their water solubility when exposed to elevated temperatures.

[0081] As indicated above, a further type of adjuvant is a release aid that assists in releasing the precursors from the substrata upon addition of the product to a wash liquor. In general, materials serving as processing aids are also suitable as release aids but certain materials, notably stearic acid and polyethylene glycols of M.Wt. 4,000 - 6,000, are particularly effective when used in amounts such that the weight ratio of precursors : release aid lies in the range 20:1 to 1:2 particularly 4:1 to 1:1. The benefits of the release aid are most clearly seen for water insoluble precursors such as 2,2-di-(4-hydroxyphenyl) propane diacctate.

[0082] A further type of rolease aid is one that is applied to the substrate either during manufacture or prior to the loading of the substrate by the precursor and any other components. Adjuvants of this type are conventionally fluorocarbons or silicone polymers adapted to modify the suriace characteristics of the substrate so as to facilitate the romoval of the active components on contact with water.
Fluorocarbon treating solutions identified as FC 807 and 808 and available from the 3M Company, Minneapolis, Minnesota, provide improved release when applied in amounts such that the weight ratio of substrate-fluorocarbon solids lies in the range 500:1 to 50:1, preferably about 300:1

[0083] In addition to the foregoing optional components, detergent ingredients other than inorganic bleaches can also be incorporated. Thus, surfactants, in addition to the nonionic-cationic mixtures specified hereinbefore, suds modifiers, chelating agents, anti-redeposition and soil suspending agents; optional brighteners, bactericides, anti-tarnish agents, enzymatic materials, fabric softeners, antistatic agents, perfumes and bleach catalysts can all be introduced into a wash liquor by means of the additive products of the present invention, subject to the constraints imposed by the loading limitations of the substrate.

[0084] The surfactant can by any one or more surface active agents selected from anionic, zwitterionic, non-alkoxylated nonionic and amphoteric classes and mixtures thereof. Specific examples of each of these classes of compounds are disclosed in Laughlin & Heuring US Patent No. 3,929,678 issued 30th December 1975, which is hereby specifically incorporated herein by reference.

[0085] The optional surfactants can be incorporated at levels such that the optional surfactant:substrate ratio is less than 10:1.

[0086] Other optional ingredients include suds modifiers which can be of the suds boosting, suds stabilising or suds suppressing type. Examples of the first type include the C₁₂-C₁₈ fatty acid amides and alkanolamides, the second type is exemplified by the C₁₂-C₁₆ alkyl dilower alkyl amine oxides and the third type by C₂₀-C₂₄ fatty acids, certain ethylene oxide-propylene oxide copolymers such as the "Pluronic" series, silicones, silica-silicone blends, micro-crystalline waxes, triazincs and mixtures of any of the foregoing.

[0087] Preferred _'suds suppressing additives are described in U.S. Patent 3,933,672 issued January 20, 1976, Bartolotta et al., incorporated herein by reference, relative to a silicone suds controlling agent. The silicone material can be represented by alkylated polysiloxane materials such as silica aerogels and xerogels and hydrophobic silicas of various types. The silicone material can be described as siloxane having the formula:

wherein x is from about 20 to about 2,000, and R and R' are each alkyl or aryl groups, especially methyl, ethyl, propyl, butyl and phenyl. The polydimethylsiloxanes (R and R' are methyl) having a molecular weight within the range of from about 200 to about 200,000, and higher, are all useful as suds controlling agents. Additional suitable silicone materials wherein the side chain groups R and R' are alkyl, aryl, or mixed alkyl and aryl hydrocarbyl groups exhibit useful suds controlling properties. Examples of the like ingredients include diethyl-, dipropyl-, dibutyl-, methyl-, ethyl-, phenylmethyl- polysiloxanes and the like. Additional useful silicone suds controlling agents can be represented by a mixture of an alkylated siloxane, as referred to hereinbefore, and solid silica. Such mixtures are prepared by affixing the silicone to the surface of the solid silica. A preferred silicone suds controlling agent is represented by a hydrophobic silanated (most preferably trimethylsilanated) silica having a particle size in the range from about 10 millimicrons to 20 millimicrons and a specific surface area above about 50 m²/gm. intimately admixed with dimethyl silicone fluid having a molecular weight in the range from about 500 to about 200,000 at a weight ratio of silicone to silanated silica of from about 19:1 to about 1:2. The silicone suds suppressing agent is advantageously releasably incorporated in a water-soluble or water-dispersible, substantially non- surface-active detergent-impermeable carrier.

[0088] Particularly useful suds suppressors are the self- emulsifying silicone suds suppressors, described in German Patent Application DTOS No. 2646217, Gault et al, published April 28, 1977, incorporated herein by reference. An example of such a compound is DC-544, commercially available from Dow Corning, which is a siloxane/glycol copolymer.

[0089] A preferred mode of incorporation of the silicone suds suppressors is as a separately impregnated area on the substrate, e.g. as a stripe onsheet-type substrates formed from continuous lengths of substrate material.

[0090] Suds modifiers as described above are incorporated at levels of up to approximately 5%, preferably from 0.1 to 2% by weight of the cationic-nonionic surfactant mixture.

[0091] Chelating agents that can be incorporated include citric acid, nitrilotriacetic and ethylene diamine tetra acetic acids and their salts, organic phosphonate derivatives such as those disclosed in Diehl US Patent No. 3,213,030 issued 19th October, 1965, by Roy US Patent No. 3,433,021 issued 14th January, 1968, Gedge US Patent No. 3,292,121 issued 9th January, 1969, Bersworth US Patent No. 2,599,807 issued 10th June, 1952, and carboxylic acid builders such as those disclosed in Diehl US Patent No. 3,308,067 issued 7th March, 1967, all of the foregoing patents being hereby incorporated herein by reference. Preferred chelating agents include nitrilotriacetic'acid (NTA), nitrilotrimethylene phosphonic acid (NTMP), ethylene diamine tetra methylene phosphonic acid (EDTMP) and diethylene triamine penta methylene phosphonic acid (DETPMP), and the chelating agents are incorporated in amounts such that the substrate-chelating agent weight ratio lies in the rance 20:1 to 1:5, preferably 5:1 to 1:5 and mos preferably 3:1 to 1:1. Certain polybasic acids have been found to enhance the bleaching effect of organic peroxyacids produced when the products of the present invention are used with conventional detergent composition, examples being EDTMP, NTMP and DETPMP. However, not all chelating polybasic acids are useful in this respect, while certain non-chelating polybasic acids, particularly succinic acid, do show efficacy.

[0092] Any of the conventional soil suspending and anti-redeposition agents can be included as optional components, examples being carboxymethyl cellulose and its derivatives and high M.Wt. copolymers of maleic anhydride with methylvinyl ether or ethylene.

[0093] A wide range of fabric softeners and antistatic agents can be included as optional compounds. Exemplary cationic nitrogen compounds include the di- C₁₆-C₁₈ alkyl, di- C₁-C₄ alkyl quaternary ammonium salts, imidazolinium salts and non-nitrogenous materials such as the sorbitan esters of C₁₆-C₁₈ fatty acids. A preferred fabric softening and antistatic composition suitable for incor- ^poration into additive products of the present invention is disclosed in US Patent No. 3,936,537 issued 3rd February, 1976 to R. Baskerville & F.G. Schiro. Compounds of this type arc disclosed in German Patent Application OLS 2,516,104 published 30th October, 1975, specifically incorporated herein by reference.

[0094] Preferred enzymatic materials include the commercially available amylases, and neutral and alkaline proteases conventionally incorporated into detergent compositions, Because of their heat sensitivity, these materials require incorhoration at or close to ambient temperatures and thus addition to a molt of the prevursor and other additives is not possible. Accordingly ensymatic materials are best

[0095] Catalysts of use heroin are those that enhance the effect of the bleaching species. Examples of such materials are the-salts of transition metals of atomic number lying between 24 and 29, utilised in conjunction with a chelating agent. Woods US Patent No. 3,532,634 issued 6th October, 1970 and specifically incorporated herein by reference discloses perborate bleach compositions containing an organic peroxy bleach precursor and catalytic compounds of this type.

[0096] The compositions herein comprise a precursor together with a nonionic-cationic surfactant mixture and optionally other ingredients in water-releasable combination with a solid non-particulate substrate. Preferably the substrate is absorbent and the materials are impregnated therein. Application of the materials can be carried out in any convenient manner, and many methods are known in the art. For example, where the materials are in liquid form they can by sprayed onto a substrate as it is manufactured. Where the precursor is in liquid form, this.can be a melt, and it is highly preferable that the precursors melt at a temperature below 'that at which they decompose on being heated. Where the precursor is a solid at normal temperatures, alternative liquid forms can be used such as solution in organic solvents which are volatilised after application, and slurries or suspensions of the finely divided solid in water or other liquid media, such as the surfactant mixture.

[0097] As previously indicated, inorganic peroxy bleaches and other materials reactive towards organic peroxy compound precursors can be incorporated in the additive products of the present invention provided that the precursor and the bleach (or other material) are spatially separated from each other.

[0098] In those embodiments in which the precursor and the inorganic peroxygcn bleach are incorporated in physically separate locations on the same substrate, a convenient method of application is the deposition of the respective melts, suspensions or solutions as discrete bands of material on the substrate. Preferably the bleach is applied as a dispersion of solid particles in a molten processing aid (as hereinbefore described) at a temeerature in the range 40° to 60°C. Using this tech- temperature in the range 40 to C. Using this technique, bleachesubstrate weight ratios of up to 15:1 can be obtained. This level of loading is attainable with cellular substrates but substrates of fibrous character are limited in practice to weight ratios of about 5:1. Furthermore, loading limitations imposed by the substrate surface area required for the incorporation of the precursor may limit the amount of bleach to less than 6:1. Provision must also be made for the separation of the bands or areas of bleach and the corresponding bands or areas of precursor during transport and/or storage. This is achieved by interposing layers of material between the layers of substrate or by producing patterns of deposited material that are not conicident on stacking of the substrate.

[0099] Where the substrate is impregnated, it is believed that the surfaces of the pores or fibres making up the substrate are themselves coated and it is a highly desirable aspect of the substrate that it permits an extensive coating of the peroxy compound precursor to be formed. The term "coating" connotes the adjoining of one substrate to the surface of another; "impregnation" is intended to mean the permeation of the entire substrate structure, internally as well as oxternally. One factor affecting a given substrate's absorbent capacity is its free space. Accordingly, when a precurson is applied to an absorbent substrate, it penetrates into the free space, hence the substrate is deemed impregnated. The free space in a substrate of low abserbency, such as a one-ply kraft or bond paper, is very limitod; such a substrate is, therefore,

a small portion of the precursor

free space avall- able in a dense substrate, a rather substantial balance of the precursor does not penetrate and remains on the surface of the substrate-so that it is deemed a coating.

[0100] In one method of making an impregnated sheet-like substrate, the impregnating mixture is applied to absorbent paper or non-woven cloth by a method generally known as padding. The mixture is preferably applied in liquid form to the substrate and precursors and other ingredients which are normally solid at room temperature should first be melted and/or solvent-treated. Methods of melting the ingredients with a solvent are known and can easily be carried out to provide a satisfactorily treated substrate.

[0101] In this method, the mixture of precursor,surfactants etc in liquid form, is placed into a pan or trough which can be heated, if necessary, to maintain the contents in liquid form. To the liquid mixture is then added any further additive. A roll of absorbent substrate is then set up on an apparatus so that it can unroll freely. As the substrate unrolls, it travels downwardly and, sub- mersed, passes through the pan or trough containing the liquid mixture at a'slow enough speed to allow sufficient impregnation. The absorbent substrate then travels, at the same speed, unwardly and through a pair of rollers which squeeze off excess bath liquid. The impregnated substrate is then colled to room temperature, after which it can be folded, cut or perforated at uniform lengths, and subsequently packaged and/or used.

[0102] The rollers used resemble "squeeze rolls" used by those in the paper and paper-making art; they can be made of hard rubber or steel. Preferably, the rollers are adjustable, so that the orifice between their respective surfaces can be regulated to control the amount of the liquid on the substrate.

[0103] In an exemplary execution of the invention, the precursor and other ingredients in liquid form, is sprayed onto absorbent substrate as it unrolls. The unrolled substrate web is arraged to slide over the spray nozzle which comprises a horizontally disposed tube formed with a slit extending along its top surface. The molten slurry of organic peroxy compound precursor surfactant mixture and any idditives mixed therewith is forced through the slit into the substrate and the excess liquid is then squeexe off by the use of squeeze rollers. A melt temperature in the range of 40°-80°C preferably 45°-65°C is "sed and the molten material should have a viscosity of less than 5000 centipoises at 50°C, preferably no more than 500 centipciscs.





rotating horizontal roll and a plate inclined thereto so as to leave a small clearance between the bottom of the plate and the roll face. A thin coating of suspension is carried downwards through the clearance and is transferred to a second horizontal roll in contact with the first but rotating in the opposite direction. This second roll is in contact with a continuously advancing web of substrate material and its direction of rotation is such as to make its direction of movement opposite to that of the substrate at the point of contact. Under these conditions the coating on the roll transfers to the substrate and impregnates it without any build up of the suspended solids occurring on the roll. In order to ensure uniform distribution of the molten suspension the impregnated substrate is preferably passed over one or more further counter rotating rolls that serve to spread the suspension evenly over the substrate before it is cooled in an air stream to solidify the impregnating material.

[0104] In order to provide a mixture having suitable characteristics ie. solidification over a range of temperature to give a waxy rather than a crystalline solid, certain of the precursors suitable for the purposes of the invention need to be blended with a plasticising or thickening agent. For this purpose the peroxy compound precursors can be divided into three different types, namely:

(a) those.that are liquid at temperatures up to 25°C or are solids melting between 25°C and 40 C

(b) solids melting between 40°C and 95⁰C,

(c) solids melting above 95^o_C.

[0105] In the high melting solid group it is preferred that the melting point be less than 150°C although materials having melting points up to 250°C can be processed by handling as a dispersion in a melt of another material. Of course it should be appreciated that the organic peroxy compound precursor should not decompose to any substantial extent at temperatures below its melting point.

[0106] Melting pcirts of a number of peroxyacid precursors suitable for use in the present invention are shown in the table below:

[0107] For the high and low melting point types a water soluble or dispersible organic adjuvant is required that has a range of.temperature over which it melts,.the adjuvant serving to provide a matrix of acceptable physical properties when impregnated on a non particulate substrate, together with acceptable viscosity temperature characteristics to facilitate impregnation itself. It should also be non-hygroscopic. The adjuvant can be a single material or more commonly a mixture of materials whose overall physical properties are satisfactory. Materials that fall into this category include the long chain fatty acids and their water-soluble or water dispersible esters, certain nonionic ethoxylates such as tallow alcohol ethoxylates having more than 10 ethylene oxide groups per mole of alcohol and high.molecular weight polyethylene glycols. Certain mixtures of cationic and nonionic surfactants, notably those incorporating a quaternary ammonium surfactant bearing a long chain carboxylate counter ion,have also been found to be satisfactory components of the water soluble adjuvant.

[0108] As indicated above, the adjuvant:precursor weight ratio can have a value of up to 10:1 but may be limited to values less than this by substrate loading constraints.

[0109] For precursor materials melting in the optimum range ie. 40 C-80 C an organic adjuvant is not essential as a processing aid in the preferred method of manufacture of products in accordance with the invention. Such materials can be melted and applied directly to the substrate and indeed may be used as carriers themselves for other components of the products such as solid chelating agents or liquid nonionic surfactants. However adjuvants of a waxy character may still be utilised in order to provide robustness to the process, for example by reducing dust, to ensure a rapid rate of release and dissolution of the precursor in aqueous media, and/or to modify the surface characteristics of the treated substrate.

[0110] In use, the additive products of the present invention are introduced into the washing liquor at a point in the washing process where formation of an organic peroxy bleaching species is of most value. In practice optimum results are obtained, irrespective of the washing cycle being employed, when the additive products of the present invention are fed into the machine at the same time as the fabric load. For machines including a prewash cycle, addition of the additive product at the beginning of the main wash cycle is preferred.

[0111] The invention is illustrated in the following non- limitative examples in which parts and percentages are by weight unless otherwise specified. Reference herein to a test method for assessing the efficacy of peroxy compound precursors in forming organic peroxy bleaching species is to the procedure as set out below.

Activator Perhydrolysis Test

[0112] In. Mole of the peroxy compound precurscr* is added to a stiried solution of sodium perborate tetrahydrate (0.9 gram; sodium pyrophosphate decahydrate (1.25 grams) EDTA (35 ppm) and 0.25 g. sodium tetrapropylene benzene sulphonate in 500 mls of distilled water maintained at 25°C by a circulating water bath and stirred mechanically.

* Water soluble precursors can by added directly. Other materials can be predissolved in 10 mls of a suitable solvent which will not react with the species present eg. 1,4 dioxan. In such cases the volume of distilled water should be reduced to 490 mls.

thiosulphate solution using an iodine indicator ('Iotect' available from British Drug Ilouses Limited) to the first end point (blue/black - colourless). Precursors which require a titre of greater than 2 mls of 0.01M sodium thiosulphate are preferred materials for the purposes of the present invention.

EXAMPLE 1

[0113] 

[0114] The substrate was drawn off the reel over feed rolls and past the lower heated roll in contact therewith, the rotation of the heated rolls being arranged such that the direction of movement of the coated roll surface and the substrate were opposed to each other. The consequent wiping action impregnated the substrate and the uniformity of the substrate loading was enhanced,, by passage over further heated rolls arranged to contact each side of the substrate. The impregnated substrate was then solidified in a current of air before being stored on a product reel and subsequently cut into sheets of approximately 120 sq ins area.

[0115] The loading of the substrate was adjusted to provide on each sheet

[0116] Sheets made up as described above had a pleasant waxy feel, a low tendency to pick up moisture on storage and when used with a conventional anionic surfactant-based perborate-containing laundry detergent provided enhanced removal of both grease and oil and oxidisable fabric stains.

EXAMPLE II

[0117] The procedure of Example I was followed using C₁₂-^C₁₄ alkyl methyl dihydroxyethyl ammonium methosulphate as the quaternary ammonium surfactant. T'he resulting sheets had acceptable feel and hygrosccpicity characteristics.

EXAMPLE III

[0118] The procedure of Example I was followed except that the cationic surfactant was C_12.5 alkyl dimethyl hydroxy propyl ammonium triborate. Sheets having acceptable feel and stain removal performance characteristics were producted.

EXAMPLE IV

[0119] The general procedure of Example I was used with the following exceptions.

[0120] A first dispersion comprised:

[0121] A second dispersion comprised:

[0122] Sheets made from the combination of the two dispersions containcd:-

* Made in accordance with the process described hereinbefore and the subject of our copending British Patent applicatior N. 8989/78 filed March with 1978, and entitled 'Process for makind Detempent Compositions'.

and had a smooth waxy feel and a reduced tendency to pick up moisture on storage. When used with a conventional laundry detergent containing anionic surfactant and sodium perborate bleach enhanced removal of a range of greasy oily stains and oxidisable stains were noted.

EXAMPLE V

[0123] The following compositions are made up in accordance with the procedure of Example I.

[0124] In these compositions, the, components are identified by the following abbreviations:-

Claims

1. A laundry additive product characterised in that it comprises

(a) a substrate comprising a non-particulate solid article in water releasable combination with,

(b) an organic peroxy compound precursor wherein the weight ratio of the precursor to the substrate lies in the range from 30:1 to 1:10, and

(c) a surfactant system comprising an alkoxylated nonionic surfactant having an HLB in the range 8.0-17.0 and a cationic surfactant having the empirical formula -

wherein _R¹ is a hydrophobic organic group containing alkyl chains optionally including aryl groups and which may also contain ether linkages, ester linkages, or amide linkages, and containing a total of from 8 to 20 carbon atoms, m is a number from one to three, and no more than one R¹ can have more than 16 carbon atoms when m is 2 and no more than 12 carbon atoms when m is 3, R² is a substituted or unsubstituted alkyl group containing from one to. four carbon atoms or a benzyl group, provided that not more than one such benzyl group is directly attached to each Y group, x is a number from zero to three, the remainder of any carbon atom positions being filled by hydrogens, Y is selected from the group consisting of





L is a number from to 10 Z is a water-soluble anion in a number to give electrical neutrality, the cationic surfactant being water dispersible in admixture with the nonionic surfactant, the weight ratio of the moniomie surfactant to the cationic surfactant being in the range 20:1 to 1:2 and the weight ratio of the surfactant system to the substrate being in the range 20:1 to 1:5.

2. A laundry additive product according to Claim 1 wherein the alkoxylated nonionic sumfactant is a C₁₀-C₁₈ linear or branched chain alcohol ethoxylate.

3. A laundry additive product according to Claim 2 wherein the nonionic surfactant is a primary C₁₀-C₁₅ substantially linear alcohol ethoxylate containing from seven to fifteen ethylene oxide groups per alcohol group.

4. A laundry additive product according to any one of Claims 1 to 3 wherein the cationie zurfactant is such that it has the structure (1), L is 1,2 is selected from C₁₀-C₂₀ alkyl and C₁₀-C₁₅ alkylbenzyl, m is 1 or 2, R₂ is selected from -CH₂C₆H_5' -CH₃, -CH₂CH₂OH and -CH₂CHOHCH₃, x is 2 or 3 and Z is a halide, methosulphate and carboxylate.

5. A laundry additive product according to any one of Claims 1 to 4 wherein the weight ratio of nonionic surfactant to cationic surfactant is within the ramge 10:1 to 1:1, preferably 5:1 to 3:2.

6. A laundry additive predict according to any one of Claims 1 to 5 wherein the weight ratio of the surfactant system t6 the substrate is within the rance 10:1 to 1:2, preferably 8:1 to 1:1.

7. A laundry additive product according to any one of Claims 1 to 6 wherein the weight ratio of the precursor to the substrate lies in the range 8:1 to 1:4, preferably 5:1 to 1:2.

8. A laundry additive product according to any one of Claims 1 to 7 wherein the precursor is selected from the group consisting of imides, acyl hydrazides, acylated oximes, anhydriden and esters.

9. A laundry additive product according to any one of Claims 1 to 8 further comprising an organic adjuvant which is a detergent component selected from surfactants other than those specified in (c) of Claim 1, suds modifiers, chelating agents, softeners, antistatic agents, anti redeposition or soil suspending agents, optical brighteners, perfumes, enzymes and mixtures of the foregoing, the amount of the detergent component or components being such that the total component:substrate weight ratio is less than 10:1 and the weight ratio of the precursor to the adjuvant being in the range from 500:1 to 10:1.

10. A laundry additive product according to Claim 9 wherein the chelating agent is selected from the group consisting of ethylene diamine tetramethylene phosphonic acid, nitrilo trimethylene phosphonic acid, diethylene triamino pentamethylene phosphonic acid and alkali metal or ammonium salts thereof.

11. A laundry additive product according to Claim 9 incorporating as an adjuvant, a suds modifier selected from C₂₀-C₂₄ fatty acids, copolymers of ethylene oxide with a hydrophobic group by condensing propylene oxide propylene glycol, polydialkyl siloxanes and mixtures thereof with silica; microcrystalline waxoc, triazine derivatives and mixtures of any of the foregoing.

12. A laundry additive product according to any one of Claims 9 to 11 wherein the adjuvant is a processing aid comprising a C₁₆-C₁₈ fatty acid.

13. A laundry additive product according to Claim 12 wherein the weight ratio of the nonionic-cationic surfactant mixture to the C₁₆-C₁₈ fatty acid is in the range 1:5 to 4:1, preferably 1:3 to 3:2.

14. A laundry additive product according to any one of the preceding Claims in the form of a flexib