Quench cooled particulate fabric softening composition

Abstract

 A detergent-compatible, dryer-released, quench cooled fabric softening composition prepared by quench cooling molten fabric softener on a cooling device, preferably a moving cooled belt. Fabric softener particles made therefrom are harder and have a more complex differential scanning calorimetry curve than a comparable nonquenched or prilled fabric softener. The average particle of this invention preferably has at least one flat or smooth surface covering at least about 10% up to 100% of its total surface area. The particulate particles are easier to coat and easier to handle.

Description

FIELD OF THE INVENTION

[0001] The invention pertains to fabric softener compositions which are included with detergent in the washing of fabrics. The fabric softener survives the wash and releases softener to the fabrics in a heated laundry dryer.

BACKGROUND OF THE INVENTION

[0002] The advantages obtained from the application of fabric conditioning agents (i.e., fabric softeners and/or antistatic agents) to laundered fabrics is well-known. The present inven­tion pertains to particulate softener/antistatic compositions which survive the wash process and release the active softening/­antistatic agent to the laundered fabrics in the dryer.

[0003] Fabric softening and antistatic benefits are a desirable part of the laundry process. Softening and antistatic compounds are, in general, quaternary ammonium compounds that are not compatible with anionic surfactants. These compounds will be referred to hereinafter as fabric softening compounds or fabric softeners, although it is to be understood that they deliver both softening and antistatic benefits to fabrics. The opposite electrical charge of the anionic surfactant used in most detergents and the quaternary ammonium fabric softening compounds leads to a mutual attraction which causes precipitation. This, in effect, removes surfactant and fabric softener from solution and reduces the cleaning capacity of the detergent while preventing effective fabric softener deposition on the fabric.

[0004] One solution to this incompatibility problem is the separate addition of the fabric softener during either the rinse cycle of the wash or while the fabrics are in the dryer. This increases the inconvenience of using fabric softeners because of the need to add them at a point in the laundering process which is different from that at which the detergent is added.

[0005] Various other solutions for this problem of incompatibility between detergent and softening compounds have been proposed in the art. U.S. Pat. No. 3,936,537, Baskerville Jr., issued Feb. 3, 1976, and U.S. Pat. No. 4,095,946, Jones, issued June 20, 1978, both incorporated herein by reference, teach the use of intimate mixtures of organic dispersion inhibitors (e.g., stearyl alcohol and fatty sorbitan esters) with solid fabric soft­ener to improve the survival of the softener in the presence of detergent in the washer so the softener can act on the fabrics when it melts in the dryer. U.S. Pat. No. 4,234,627, Schilling, issued Nov. 18, 1980, teaches microencapsulation of fabric soft­ener. The microcapsules survive the wash and adhere to the fabric surface. They are then ruptured by subsequent tumbling of the fabric in the dryer, thereby releasing softener to the fabrics. Fabric softener prills with a water-insoluble coating are known. However, the commercial production of such softener prills can be very expensive due to low yields.

[0006] Likewise, slowly cooling molten fabric softener in trays and grinding to the desired size is a state-of-the-art procedure that can be time consuming and can produce sticky softener particles; particles which are also jagged shaped granules with "fissures".

[0007] Thus, there is a continuing need for improved methods and compositions which are more suitable for conveniently and effec­tively preparing particulate fabric softeners for the home laundering process.

[0008] An object of the present invention is to provide a harder softener particulate which has a smooth surface without fissures.

[0009] It is also an object of the present invention to provide particulate fabric softener which survives the detergent wash solution and releases the softener to the fabrics at dryer temperatures.

[0010] Another object is to provide an improved process for making an improved and less sticky particulate fabric softener.

SUMMARY OF THE INVENTION

[0011] The present invention is directed to detergent-compatible, particulate, dryer-activated quench cooled cationic fabric softener having a differential penetration value of at least about 0.1 mm less than a comparable but nonquench cooled fabric softener composition. The particulate fabric softener of the present invention preferably has at least one surface which is sub­stantially smooth or flat. The smooth or flat surface area pref­erably ranges from about 10% to about 100% of the surface area of the particulate. In another respect, the present invention relates to an improved process for making particulate fabric softener, said process comprising quench cooling molten fabric softener via intimate contact with a solid cooling device.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention is directed to detergent-compatible, dryer-activated fabric softening particles comprising a quench cooled cationic fabric softener composition. This invention also relates to a quench cooled fabric softener process for preparing same. The invention also relates to laundry detergent compo­sitions containing said quench cooled softener particles. The quench cooled fabric softener composition (particles) can be added to the wash step of the fabric laundering process.

[0013] The process comprises quenching molten fabric softener on a cooling device. The softener is formulated to survive the wash and is released to the fabrics in a heated laundry dryer.

The Quench Cooled Softener Composition

[0014] The quench cooled, detergent-compatible, dryer-activated fabric softener composition of this invention comprises from about 70% to about 100% of fabric softener material, at least about 10% of which is a cationic fabric softener. The quench cooled softener composition has a melting point of from about 40°C to about 80°C, preferably from about 45°C to about 60°C. The quench cooled softener of the present invention is cooled by intimately contacting the molten fabric softener to a cooling device, pref­erably a moving belt cooler or a chilled rolls. The molten fabric softener is metered onto the cooling device as a thin film or a particulate where it is solidified in a few seconds.

[0015] Preferably, the molten fabric softener is applied to the cooling device as a thin film having a preferred thickness of from about 0.3 mm to about 6.4 mm, more preferably from about 0.4 mm to about 4.4 mm, and most preferably from about 0.5 mm to about 2.5 mm.

[0016] While not being bound to any theory, it is believed that a harder, more uniform crystalline softener material is formed via the intimate contact with the cooling device. The differential scanning curve (DSC) of a quench cooled softener is wavier than that of a slow cooled softener. A quench cooled softener is theorized to have a more complex DSC curve than the nonquench cooled softener.

[0017] Nonquench cooled softener can be made from molten fabric softener which is conventionally cooled solid in several minutes to several hours or cooled in a spray tower. In a conventional spray tower process, molten fabric softener is cooled quickly, however, such prills are distinguished from the quench cooled softeners of the present invention in that they are not in intimate contact with a solid cooling device. The quench cooled softener of the present invention is harder than comparable prilled fabric softener.

[0018] The quench cooled softener composition of this invention has a differential penetration value of at least about 0.1 mm less than a comparable nonquench cooled softener composition. The differ­ential penetration value can be less than 0.2 mm or less than about 0.4 mm. Penetration values herein are measured by ASTM Test D-1321 modified by using a 100 gm weight. Softener prills have numerous air holes and are much softer than the quench cooled and nonquench tray cooled softener because the latter two are more solid.

[0019] The quench cooled softener compositions of the present invention can have an absolute penetration value of up to about 2 mm, but preferably less than 1.5 mm, and more preferably about 1 mm or less. Within particle limits, the harder the soft­ener particle the better the handling of the particle for coating and packing purposes. The harder they are the less sticky and the better the handling.

[0020] In particulate form the quench cooled fabric softener com­position can have from 0% to about 30% of a coating surrounding the particulate fabric softener composition. The coating is preferably a substantially water-insoluble material having a melting point above about 35°C and a penetration value of about 0.6 mm or less.

[0021] The quench cooled fabric softener particles preferably have diameters of from about 100 microns to about 5,000 microns, pref­erably from about 300 microns to about 3,000 microns, and most preferably greater than about 500 microns up to about 2,000 microns, with a number average of from about 500 to about 1,200 microns. The particles can be of a generally spherical shape, but can have an irregular cubical shape with one or more flat or smooth surfaces. The particle sizes quoted herein refer to the largest dimension (diameter thickness or length) of the particle.

Preparation of Quench Cooled Softener Composition

[0022] In preparing the quench cooled fabric softener composition of this invention, molten fabric softener is applied onto a quenching device having a temperature below the melting point of the softener composition. The molten softener can be applied to the cooling device in the form of particles, ribbons, sheets, etc., whereby a heat exchange occurring between the cooling device and softener solidifies or quenches the molten softener solid. This "quenching" effect on the softener composition is believed to provide a harder or more crystalline softener. The quenched fabric softener has a greater area under its DSC curve than a comparable slow-cooled softener.

[0023] The process itself is more robust, more flexible than prill­ing, yet provides a superior softener product. The particles made from the quenched fabric softener are more conducive to encapsulation. The quench cooled softener has more flat surfaces than tray cooled softeners. The flat surfaces allow more efficient coating. The processing time is reduced and the yields are high. Some quench cooled processes provide softener particles which are more uniform in size.

[0024] The processing window is wider for the process of the present invention than for the processes of the prior art. Glue guns, spray nozzles, etc., can be used to spray the molten softener onto the cooling device to achieve tailored quenched particles. A weir or a similar device can be used to meter a sheet or a ribbon of molten softener onto the cooling device. The solid softener can then ground to a tailored particle size. An electronically controlled pastille-forming apparatus or a screen printer can be used to provide uniform softener particles. In the light of this disclosure, there are numerous other equivalent variations as will be known to one skilled in the art.

Preferred Cooling Device

[0025] Preferred cooling devices are steel belt coolers and chill rolls. A preferred cooling device commercially available is a Sandvik Rotoform System comprising dropformers or weirs, and a rotating steel belt cooler (Sandvik Process Systems, Inc., Totowa, New Jersey 07512). Another cooling belt manufactured by the Berndorf International Conveyor Belts, Inc., Schaumburg, Illinois 60193.

[0026] The cooling device must be capable of releasing the quenched cooled softener product via doctoring or some other separation means and is thus distinguished from substrate impreg­nated cooled softener.

The Softener Component

[0027] Typical cationic fabric softeners useful herein are quaternary ammonium salts of the formula
[R₁R₂R₃R₄N]⁺Y⁻
wherein one or two of R₁, R₂, R₃ and R₄ groups is an organic radical containing a group selected from a C₁₂-C₂₂ aliphatic radical or an alkylphenyl or alkylbenzyl radical having from 10 to 16 carbon atoms in the alkyl chain, the remaining groups being selected from C₁-C₄ alkyl, C₂-C₄ hydroxyalkyl and cyclic struc­tures in which the nitrogen atom in the above formula forms part of the ring, and Y constitutes an anionic radical such as halide, nitrate, bisulfate, methylsulfate, ethylsulfate and phosphate, to balance the cationic charge.

[0028] In the context of the above definition, the hydrophobic moiety (i.e., the C₁₂-C₂₂ aliphatic, C₁₀-C₁₆ alkyl phenol or alkylbenzyl radical) in the organic radical R₁ or R₂ may be directly attached to the quaternary nitrogen atom or may be indirectly attached thereto through an amide, ester, alkoxy, ether, or like grouping.

[0029] The quaternary ammonium compounds useful herein include both water-soluble compounds and substantially water-insoluble compounds which are dispersible in water. For example, imidazolinium compounds of the structure

wherein R is a C₁₆ to C₂₂ alkyl group, possess appreciable water solubility, but can be utilized in the present invention.

[0030] The quaternary ammonium softener compounds used in this invention can be prepared in various ways well-known in the art and many such materials are commercially available. The quat­ernaries are often made from alkyl halide mixtures corresponding to the mixed alkyl chain lengths in fatty acids. For example, the ditallowalkyl quaternaries are made from alkyl halides having mixed C₁₄-C₁₈ chain lengths. Such mixed di-long chain quater­naries are useful herein and are preferred from a cost stand­point.

[0031] The anionic group which can be the counter-ion in the quaternary compounds useful herein is typically a halide (e.g., chloride or bromide), nitrate, bisulfate, ethylsulfate, or methyl­sulfate. The methylsulfate and chloride ions are the preferred counter-ions from an availability standpoint; while the methylsul­fate anion is most preferred because of its minimization of cor­rosive effects on the automatic clothes dryers in which it is used.

[0032] The following are representative examples of quaternary ammonium softening compounds suitable for use in the present invention. All the quaternary ammonium compounds listed can be included in the present invention, but the compilation of suitable quaternary compounds hereinafter is only by way of example and is not intended to be limiting of such compounds. Dioctadecyldi­methylammonium methylsulfate is an especially preferred fabric softening compound for use herein, by virtue of its high anti­static, as well as fabric softening activity; ditallowalkyldi­methylammonium methylsulfate is equally preferred because of its ready availability and its good antistatic activity; other useful di-long chain quaternary compounds are dicetyldimethylammonium chloride, didocosyldimethylammonium chloride, didodecyldimethyl­ammonium chloride, ditallowalkyldimethylammonium bromide, diole­oyldimethylammonium methylsulfate, ditallowalkyldiethylammonium chloride, ditallowalkyldipropylammonium bromide, ditallowalkyl­dibutylammonium fluoride, cetyldecylmethylethylammonium chloride, bis-[ditallowalkyldimethylammonium] bisulfate, tris-[ditallowalkyl­dimethylammonium] phosphate, 1-methyl-1 -tallowamidoethyl-2-­tallowimidazolinium methylsulfate, and the like. Particularly preferred quaternary ammonium fabric softening compounds are ditallowalkyldimethylammonium chloride and ditallowalkyldimethyl­ammonium methylsulfate.

Coated Quenched Fabric Softener Particles

[0033] In a preferred embodiment the fabric softener is the core of particles and comprises from about 70% to about 97% and most preferably about 85% to about 97% of the particle. All percent­ages herein are "by weight" unless otherwise indicated.

[0034] The core composition can consist entirely of cationic fabric softeners, and will generally comprise at least 10%, usually 10% to 50% cationic fabric softener. Optionally, and preferably, the core can contain additional materials such as perfume, auxiliary fabric softening agents (e.g., smectite clay, fatty alcohols and fatty amine, such as ditallowmethyl amine or 1 -tallowamidoethyl-2-tallow­imidazoline), soil release agents, fabric brighteners, etc. Addi­tional disclosure of materials which can be applied to fabrics along with cationic fabric softening agents in a laundry dryer and, therefore, can be part of the core composition of the particles herein, are disclosed in U.S. Pat. Nos. 4,073,996, Bedenk et al., issued Feb. 14, 1978; 4,237,155, Kardouche, issued Dec. 2, 1980; and 4,421,792, Rudy et al., issued Dec. 20, 1983, all incorpo­rated herein by reference. Preferred additional materials are the encapsulated fabric conditioning perfume microcapsules of U.S. Pat. No. 4,234 ,627, Schilling issued Nov. 18, 1980, and British Pat. No. 1,549,432, both of which are incorporated herein by reference. A particularly preferred process for preparing such capsules is disclosed in U.S. Pat. No. 3,697,437, Fogle et al., issued Oct. 10, 1972, incorporated herein by reference. Particle sizes of from about 100 to about 200 microns are preferred.

[0035] Preferably, the core has an outer coating which completely surrounds the core and comprises a substantially water-insoluble material having a melting point above 35°C, preferably above 50°C. By "substantially water-insoluble" herein is meant having a solubility in 35°C water of less than about 50 ppm.

[0036] The coating materials are substantially water-insoluble materials, typically (but not necessarily) selected from waxy materials such as paraffinic waxes, microcrystall ine waxes, animal waxes, vegetable waxes, saturated fatty acids and fatty alcohols having from 12 to 40 carbon atoms in their alkyl chain, and fatty esters such as fatty acid triglycerides, fatty acid esters of sorbitan and fatty acid esters of fatty alcohols, or from sub­stantially water-insoluble polymers. Typical specific suitable waxy coating materials include lauric, myristic, palmitic, stearic, arachidic and behenic acids, stearyl and behenyl alcohol, micro­crystalline wax, beeswax, spermaceti wax, candelilla wax, sor­bitan tristearate, sorbitan tetralaurate, tripalmitin, trimyristin and octacosane. A preferred waxy material is stearyl alcohol.

[0037] Examples of water-insoluble polymeric materials which may be used for the coating of the particles herein are cellulose ethers such as ethyl, propyl or butyl cellulose; cellulose esters such as cellulose acetate, propionate, butyrate or acetate-butyrate; urea-­formaldehyde resins, polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, polyacrylates, polymethacrylates, polymethyl-methacrylates and nylon. Such materials and their equivalents are described in greater detail in any conventional handbook of synthetic organic plastics, for example, in Modern Plastics Encyclopaedia Volume, Vol. 62, No. 10A (for 1985-1986) at pages 768-787, published by McGraw-Hill, New York, N.Y. (October 1985), incorporated herein by reference. A preferred polymeric material is ethyl cellulose. The polymeric coating materials can be plasticized with known plasticizing agents such as phthalate, adipate and sebacate esters, polyols (e.g., ethylene glycol) tricresyl phosphate, castor oil and camphor.

[0038] The coating surrounds the cationic fabric softener core and is present in an amount of from 0% to about 30%, preferably from about 3% to about 15% by weight of the particle.

[0039] The coating material can comprise a mixture of waxy coating materials and polymeric coating materials. In such mixtures the waxy coating material will typically comprise from about 70% to about 90% of the mixture and the polymeric material about 30% to about 10%.

[0040] Typically, the coating material will have a hardness which corresponds to a needle penetration value of about 0.6 mm or less, and preferably less than about 0.1 mm, as measured by ASTM Test D-1321 modified by using a 100g weight instead of a 50g weight. The test is performed at 25-27°C. In the case of polymeric coating materials, sample preparation is accomplished by dissolving the polymer in a volatile solvent and then evaporating the solvent after the polymer solution has been placed in the test container. For waxy coating materials, sample preparation is done by melting the sample and then solidifying it in the test container in the manner set forth in the ASTM method.

[0041] Penetration values of a number of suitable coating materials are shown in the following table.

TABLE 1

Penetration Values of Representative Coating Materials
Material	Penetration in mm
Stearyl alcohol	0.57
Ethyl cellulose	0.09
Cellulose acetate	0.00
Ethyl cellulose + 10% dibutyl sebacate	0.00
70% Stearyl alcohol + 30% C₃₀ alcohol	0.32
90% Stearyl alcohol + 10% Elvax-4310¹	0.12
90% Stearyl alcohol + 10% BE-Square-195²	0.40

¹ Terpolymer of ethylene, vinyl acetate and acid from DuPont

² Microcrystalline wax from Petrolite, Specialty Polymers Group

[0042] The function of the coating which surrounds the fabric softener is to prevent the softener from becoming dissolved and/or dispersed in the wash water when the particles are pres­ent during the wash step of a laundry process, and thereby prevent interaction between the fabric softener and the deter­gent. During the washing and rinsing of the fabrics, a substan­tial amount of the particles adhere to, or become entrapped within folds of the fabrics. When the fabrics are dried in a heated automatic clothes dryer (typically at temperatures of about 65° to 85°C), the coating and the fabric softener core composition melt, thereby permitting the softener to spread throughout the fabric load and soften the fabrics.

[0043] If the particles are incorporated into a granular detergent composition, it is preferred that the particle size of the softener particles be similar to the particle size of the detergent granule in order to minimize segregation. This will typically be in the range of from about 500 to about 1000 microns. Softener particles which are smaller in size than the detergent granules can be agglomerated to form larger particles to match the particle size of the detergent granules into which they will be incorporated. The agglomeration can be accomplished by using water-soluble or dispersible materials such as polyvinyl alcohol, sodium carboxy­methyl cellulose, gelatin and polyoxyethylene waxes. The agglom­erates disintegrate when the detergent composition is added to water. Methods and agglomerating agents for agglomeration of fabric softener particles are described in U.S. Pat. No. 4,141,841, McDanald, issued Feb. 27, 1979, incorporated by reference herein.

[0044] The particles of softener composition are preferably coated with coating material which is either melted or dissolved in a volatile solvent. The coating is done at a temperature which is below the melting point of the softener composition, and the coated particles are then cooled (or the solvent is evaporated) to solidify the coating. The coating is typically applied in a fluid­ized bed type apparatus. A suitable type of apparatus is that described in U.S. Pat. No. 3,196,827, Wurster et al., issued July 27, 1965, incorporated by reference herein. In this appa­ratus, solid softener core particles are suspended on an air stream which carries them in a smooth cyclic flow past the coating nozzle, which sprays them with fluid coating material. Air atom­izes and expels the coating fluid through the coating nozzle. The atomized coating fluid covers the surfaces of the core particles. The coated particles are lifted on the air stream and the fluid coating solidifies on the surface of the particles as the air stream lifts them away from the nozzle. The particles then settle out of the air stream and begin another cycle which takes them past the nozzle again. The process is repeated until the desired amount of coating has been deposited on the particles. The amount of coating applied to the softener core particles is typically from about 3% to about 30%, preferably about 3% to about 15% by weight of total particle (i.e., core plus coating).

[0045] Alternatively, other types of encapsulating processes such as described in an article by Nack entitled "Microencapsulation Techniques, Applications and Problems," J. Soc. Cos. Chem., Vol. 21, Pages 85-98 (Feb. 4, 1970), incorporated herein by reference, can be used. When perfume microcapsules are incor­porated, the processes disclosed in U.S. Pat. No. 4,234,627, supra, incorporated herein by reference, can be used.

[0046] If it is desired to aggomerate the softener particles, this can be accomplished in the following manner. The softener particles are fed to a highly efficient mixer (e.g., Schugi Flexomix Model 160,335 or 400 from Schugi Process Engineers USA, 41-T Tamarack Circle, Skillman, New Jersey 08558), or a pan agglom­erator. Aqueous solution or dispersion of agglomerating agent is sprayed onto the moving particles causing them to stick to each other. The water is evaporated and the dried agglomerated particles are sized by sieving. Suitable agglomerating agents include dextrin starches, Pluronic Polyols (copolymers of ethylene oxide and/or propylene oxide with either ethylene glycol or propylene glycol) and hydratable salts such as sodium tripoly­phosphate or sodium sulfate.

[0047] The type of apparatus described in U.S. Pat. No. 3,196,827 (Wurster et al.), cited supra, can also be used for agglomerating particles.

Detergent Compositions

[0048] The particles of the present invention are preferably formu­lated into detergent compositions. Such compositions typically comprise detersive surfactants and detergency builders and, optionally, additional ingredients such as bleaches, enzymes, fabric brighteners and the like. The particles are present in the detergent composition at a level sufficient to provide from about 0.5% to about 10%, and preferably from about 1% to about 5% of quaternary ammonium fabric softener in the detergent composition. The remainder of the detergent composition will comprise from about 1% to about 50%, preferably from about 10% to about 25% detersive surfactant, and from about 15% to about 60%, preferably from about 20% to about 45% of a detergency builder, and, if desired, other optional laundry detergent components.

1. The Surfactant

[0049] Surfactants useful in the detergent compositions herein include well-known synthetic anionic, nonionic, amphoteric and zwitterionic surfactants. Typical of these are the alkyl benzene sulfonates, alkyl- and alkylether sulfates, paraffin sulfonates, olefin sulfonates, alkoxylated (especially ethoxylated) alcohols and alkyl phenols, amine oxides, alpha-sulfonates of fatty acids and of fatty acid esters, alkyl betaines, and the like, which are well known from the detergency art. In general, such detersive surfactants contain an alkyl group in the C₉-C₁₈ range. The anionic detersive surfactants can be used in the form of their sodium, potassium or triethanolammonium salts; the nonionics generally contain from about 5 to about 17 ethylene oxide groups. C₁₁-C₁₆ alkyl benzene sulfonates, C₁₂-C₁₈ paraffin-sulfonates and alkyl sulfates are especially preferred in the compositions of the present type.

[0050] A detailed listing of suitable surfactants for the detergent compositions herein can be found in U.S. Pat. No. 3,936,537, Baskerville, issued Feb. 3, 1976, incorporated by reference herein. Commercial sources of such surfactants can be found in McCutcheon's EMULSIFIERS AND DETERGENTS, North American Edition, 1984, McCutcheon Division, MC Publishing Company, also incorporated herein be reference.

2. Detergency Builders

[0051] Useful detergency builders for the detergent compositions herein include any of the conventional inorganic and organic water-soluble builder salts, as well as various water-insoluble and so-called "seeded" builders.

[0052] Nonlimiting examples of suitable water-soluble, inorganic alkaline detergent builder salts include the alkali metal carbo­nates, borates, phosphates, polyphosphates, tripolyphosphates, bicarbonates, silicates, and sulfates. Specific examples of such salts include the sodium and potassium tetraborates, bicarbonates, carbonates, tripolyphosphates, pyrophosphates, and hexameta­phosphates.

[0053] Examples of suitable organic alkaline detergency builder salts are: (1) water-soluble amino polyacetates, e.g., sodium and potassium ethylenediaminetetraacetates, nitrilotriacetates, and N-(2-hydroxyethyl)nitrilodiacetates; (2) water-soluble salts of phytic acid, e.g., sodium and potassium phytates; (3) water-­soluble polyphosphonates, including sodium, potassium and lithium salts of ethane-1-hydroxy-1,1-diphosphonic acid, sodium, potas­sium, and lithium salts of methylenediphosphonic acid and the like.

[0054] Seeded builders include such materials as sodium carbonate or sodium silicate, seeded with calcium carbonate or barium sulfate.

[0055] A detailed listing of suitable detergency builders can be found in U.S. Pat. No. 3,936,537, supra, incorporated herein by reference.

3. Optional Detergent Ingredients

[0056] Optional detergent composition components include enzymes (e.g., proteases and amylases), halogen bleaches (e.g., sodium and potassium dichloroisocyanurates), peroxyacid bleaches (e.g., diperoxydodecane-1,12-dioic acid), inorganic percompound bleach­es (e.g., sodium perborate), activators for perborate (e.g., tetraacetylethylenediamine and sodium nonanoyloxybenzene sulfo­nate), soil release agents (e.g., methylcellulose) soil suspending agents (e.g., sodium carboxymethylcellulose) and fabric bright­eners.

Pouched Products

[0057] When free fabric softener particles of the invention are added to the wash step of a laundering process, it is inevitable that some of the particles will not adhere to or become trapped in the folds of the fabrics and will, therefore, be lost in the dis­carded wash solution or rinse water. In order to avoid such loss, the particles can be added to the wash solution in a sealed, porous water-insoluble pouch such as the type described in U.S. Pat. No. 4,223,029, Mahler et al., issued Sept. 16, 1980, incor­porated by reference herein. Detergent granules can be included in the pouch with the softener particles. When the pouch is placed in water in the wash step of the laundering process, the detergent dissolves, but the softener particles remain in the pouch. The pouch remains with the fabrics through the wash and rinse. When the pouch is tumbled with the fabrics in the dryer, the softener particles release the softener, which melts onto the pouch material and is transferred from the pouch material to the fabrics as the pouch comes into contact with the fabrics during the drying cycle. Preferred pouch structures are multi-pouch porous sheet structures such as described in U.S. Pat. No. 4,638,907, Bedenk/Harden, issued Jan. 27, 1987, incor­porated herein by reference. A single pouch structure can also be used. Several examples are currently on the market.

[0058] Some preferred pouches and detergent compositions are disclosed in commonly assigned and allowed U.S. Pat. Appln. Ser. No. 055 ,802, filed Jan. 16, 1987, Ping/Beard, entitled "Glue Patterned Substrate for Pouched Particulate Fabric Softener Laundry Product"; and U.S. Pat. Appln. Ser. No. 017,103, Hortel/Ciauss/Williamson, filed Feb. 19, 1987, entitled "A Soil Release Polymer Coated Substrate Containing a Laundry Detergent for Improved Cleaning Performance"; both incorporated herein by reference in their entirety.

[0059] Suitable pouch materials include, paper, nonwoven synthetics such as spunbonded and wet laid polyester, and porous formed film plastic sheet material. Suitable formed plastic film material is disclosed in commonly assigned U.S. Pat. No. 4,679,643, Curro and Linman, issued Dec. 16, 1986. Said film has finely divided apertures smaller than most of the particulate materials inside and is capable of surviving the wash and dryer temperatures.

[0060] The invention will be illustrated by the following nonlimiting examples.

EXAMPLE I

[0061] Molten fabric softener which has a melting point of about 54°C is prepared using the following formula:

Ingredient	Wt. %
Ditallowdimethylammonium methylsulfate (DTDMAMS)	44
Sorbitan monostearate	22
Cetyl alcohol	22
Syloid® 234 (silica gel)	12
Total	100

[0062] The DTDMAMS is heated in a reaction vessel at 71°C under vacuum (Ca. 710 mm Hg) for 4 hours to remove residual moisture and/or isopropanol. The cetyl alcohol and sorbitan monostearate are then added, and the molten "triblend" is mixed for one hour at about 71°C.

[0063] The triblend is transferred into a Ross Versamix mixer (Charles Ross & Sons Company, Hauppauge, New York 11788). The temperature of the triblend is then raised to 79°-85°C under vacuum (about 330-430 mm Hg). When the temperature has stabilized in this range, the Ross anchor and disperser are turned on and the Syloid 234 is added. The mixture is blended for 5 minutes and then sheared with the Ross colloid mixer for 20 minutes. (Some of the molten softener composition is poured into trays and cooled overnight in a 4°C room. Thickness: 1.5 mm. This is used as a control.)

[0064] The molten softener mixture is transferred or pumped to the head of a steel belt cooler via heated piping. The softener is placed on the moving steel belt cooler, a Sandvik Process System belt (Sandvik Process Systems, Inc., Totowa, NJ 07512) directly from the piping, via a distribution bar or a distribution piping across the width of the belt. A weir is used to meter the molten softener in the form of a 0.06 inch (1.5 mm) thick film onto the moving cooled belt. The belt is cooled via waterjets underneath the belt. The temperature range in the first meter zone is from 32°-38°C, the second zone from 20°-32°C, and the third zone from 10°-20°C and combinations. Each zone is about 5 meters. The length of the belt is 18 meters. The belt is moving at a rate of about 40 feet (13 meters/min.) per minute, but can be adjusted to a rate of from about 30 to 80 feet per minute (9 to 25 meters per minute). The molten softener becomes solid film in about 40 seconds.

[0065] The film of softener traveling along the belt is quenched below its melting point, in this case the quenching temperature is below 32°C. The object is to quench the softener while main­taining intimate contact between the softener and the belt. Separation of the softener (curling up) by instantaneous quench­ing still produces a superior softener product. However, it is desirable to meter the softener onto the cooled belt at a tem­perature which will maintain maximum contact with the belt during the entire quenching process.

[0066] Quench cooled softener is released from the cooling belt by a doctoring device at the end of the belt and is delivered to a prebreaker, which breaks the solidified film into particles less than 4 inches (10.16 cm) in diameter.

[0067] However, some of the quench cooled softener is taken after being doctored off the belt but before prebreaking the sample to measure the hardness of the softener film.

[0068] The quench cooled softener of this example had a penetration value of about 0.8 mm and the above-mentioned overnight cooled controlled fabric softener had a penetration value of about 1 mm. A 0. 1 mm difference penetration is a significant difference.

[0069] The solid quenched softener prebreak is then converted to particles by milling in a Fitzmill, Model DAS06 (The Fitzpatrick Company, Elmhurst, Illinois 60126) at 4740 rpm's through a 4 mesh screen. The particles are then sized through 12 on 30 (U.S. Standard screens, 1.7-0.6 mm particle size). The particles of this example are cubical in shape with one or two flat sur­faces. There are little or no fissures on the particle surfaces.

EXAMPLE II

[0070] To improve the hot water wash survivability of the softener, the particles of Example I are coated with a hot melt of fatty alcohol-based coating. The coating is a mixture of 90% stearyl alcohol and 10% Elvax-4310, a terpolymer of ethylene, vinyl acetate and acid from E.I. du Pont de Nemours & Co., Polymer Products Dept., 1007 Market St., Wilmington, Delaware 19898. The coating is applied in an 18 Inch Wurster coater (Coating Place, Inc., P.O. Box 248, Verona, Wisconsin 53593). A de­tailed description of this type of equipment can be found in U.S. Pat. No. 3,196,827, supra, incorporated by reference herein.

[0071] Briefly, the Wurster Coater consists of an apparatus that is capable of suspending the softener core particles on a rapidly moving warm air stream. Encapsulation is accomplished by pass­ing the quench cooled softener particles through a zone of finely atomized droplets of coating. As the particles move up and away from the coating nozzle, the coating begins to solidify as the particles cool. When the particles can no longer be fluidized by the air stream, they move down in the opposite direction of the fluidizing air. The coated particles then reenter the coating zone and are recycled until the desired amount of coating is applied. The coating cycle takes place within a single chamber which preferably has a partition to separate the particles moving up through the coating zone from those moving down through the cooling zone.

[0072] The following conditions are used to apply a hot melt coating:

Stearyl Alcohol/Elvax Temperature	79°C
Fluidizing Air	15.8 Cu.M/min. at 40.5°C
Atomizing Air Volume	0.25 Cu.M/min.
Atomizing Air Rate	4218 g/sq.cm.
Inlet Air Temperature	20°C - 38°C
Outlet Air Temperature	20°C - 38°C
Pump Rate	0.2 Kg/min.
Nozzle Size	CPI-18-A74*
Partition Size	216 mm x 267 mm
Partition Gap	19 mm
Run Time	22 min.

*Available from Coating Place, Inc.

[0073] The amount of fatty alcohol coating applied to the quench cooled softener particles is about 15% by weight of the total coated particle. After the coating process is complete the par­ticles are resized through 12 on 20 mesh and are then ready for use "as is" or for blending into detergent granules.

EXAMPLE III

[0074] Quench cooled softener core particles prepared as in Example I are coated with ethyl cellulose based coating instead of fatty alcohol. The particles are coated with a 10% solution of Ethocel in methanol. The coating is applied in an 18 inch Wurster Coater (Coating Place, Inc., P.O. Box 248, Verona, Wisconsin 53593). The ethyl cellulose used is Ethocel Std. 10 (Dow Chemical Co., Midland, Michigan 48640), which has an Ubbelohde viscosity of 9.0-11.0, measured at 25°C as a 5% solution in 80% toluene/20% ethanol.

[0075] The following conditions are used to apply the cellulose-­based coating:

Fluidizing Air	15.8 Cu.M/min. at 40.5°C
Atomizing Air Volume	0.37 Cu.M/min.
Atomizing Air Rate	5624 g/sq.cm.
Inlet Air Temperature	38°C - 43°C
Outlet Air Temperature	30°C - 32°C
Pump Rate	0.2 Kg/min.
Nozzle Size	CPI-18-A74*
Partition Size	216 mm x 267 mm
Partition Gap	19 mm
Run Time	55 min.

*Available from Coating Place, Inc.

[0076] The amount of ethyl cellulose solids coated onto the particles is about 3% by weight of the total coated particle weight. When the coating is completed, the softener particles are resized through 11 on 26 Mesh U.S. Standard screens and are then ready for use "as is" or for blending into detergent granules.

EXAMPLE IV

[0077] A granular detergent/softener composition is prepared by mixing 4 parts of the quench cooled softener particles of either Example I, II or III with 96 parts of the following granular detergent composition.

Ingredient	Wt.%
Sodium C₁₃ linear alkylbenzene sulfonate	16.5
Sodium C₁₄-C₁₅ linear fatty alcohol sulfate	16.5
Sodium sulfate	23.8
Sodium silicate	9.2
Polyethylene glycol	0.9
Polyacrylic acid	1.3
Sodium tripolyphosphate	13.7
Sodium carbonate	4.8
Methyl cellulose	3.6
Optical brightener	1.3
Protease enzyme	1.6
Moisture and miscellaneous	6.8
Total	100.0

EXAMPLE V

[0078] A granular bleach/softener composition is prepared by mixing 4 parts of the quench cooled softener particles of either Example I, II or III with 96 parts of the following granular bleach compo­sition.

Ingredient	Wt.%
Diperoxydodecanedioic acid	24.0
Dodecanedioic acid	2.9
Sodium C₁₃ linear alkylbenzene sulfonate	5.5
Boric acid	27.7
Sodium sulfate	39.7
Miscellaneous	0.2
Total	100.0

EXAMPLE VI

[0079] A laundering article in the form of a multipouch sheet is prepared as follows.

[0080] The sheet is comprised of two sheets of Reemay® 2420 spun­bonded polyester (Dupont, Wilmington, Delaware). In between the sheets is a honeycomb web made from polyethylene. The web has a thickness of approximately 0.04 inch (0.10 cm) and the cells of the web are diamond shaped, having a cross dimension of approximately 0.19 inch (0.48 cm) and a length dimension of approximately 0.63 inch (1.60 cm). The three-layered structure has outer edge dimensions of approximately 4.5 inches x 11 inches (11 .4 cms x 27.9 cms). The structure is laminated together in a pattern so as to form six equal sized pouches, two pouches at each end containing about 14.7 grams each of the bleach/quench cooled softener composition of Example III and the four pouches in between containing about 15.5 grams each of the detergent/­quench cooled softener composition of Example IV.

[0081] The article is suitable for washing and softening laundry in a process involving washing and rinsing the fabrics, followed by tumble drying in a heated clothes dryer, wherein the article remains with the laundry throughout the entire process.

EXAMPLE VII

[0082] This example is the same as Example VI, except that (1) the softener and detergent levels are, respectively, 2.2 parts and 97.8 parts, (2) the softener and bleach levels are, respectively, 2.6 parts and 97.4 parts; and (3) the multipouched sheet is comprised of a top sheet of a latex bonded, wet laid polyester/­wood pulp substrate (James River 5227, James River Corp., Greenville, South Carolina) and an embossed sheet of Reemay® 2420, a spunbonded polyester (Dupont, Wilmington, Delaware). The two sheets are laminated together with an outer edge dimen­sion of approximately 4.5 inches x 11 inches (11.4 x 27.9 cms) and with a pattern so as to form six equal sized pouches. The two pouches at each end are filled with about 14.7 grams of the bleach/ethyl cellulose coated softener composition of Example III and the four pouches in between are filled with about 15.5 grams of the detergent/ethylcellulose coated softener composition of Example III.

[0083] When a dusty detergent powder is used in a pouched sheet, as set forth above, the porous substrates may not be able to contain the dust adequately. One solution to this problem is to spray the inside of the detergent pouches with a wetting agent selected from suitable, relatively nonvolatile, organic liquids like water, surfactant solutions, propylene or ethylene glycol, light oils, liquid polyethylene glycols, nonionic surfactants, etc., capable of forming and maintaining a tacky surface on the detergent powder particles. Said liquid should not be capable of forming, by itself, a barrier of any type between the substrate and the detergent composition. The portion of the substrate that defines the pouch that contains the detergent powder is sprayed with an effective amount, typically from about 0.01 gram to about 0.2 gram per square inch, preferably from about 0.04 gram to about 0. 1 gram per square inch, of said wetting agent. The detergent powder is added to the detergent pouch before the wetting agent evaporates or otherwise disappears. The tacky detergent powder then obstructs, at least partially, the pores of the substrate, and thus minimizes the escape of the very fine detergent powder particles (dust). The porous substrate in this Example is coated with approximately 0.06 gram per square inch of organic liquid (propylene glycol) and, before it dries, the detergent powder is added to the sheet.

[0084] The finished article is suitable for washing and softening laundry in a process involving washing and rinsing the fabrics, followed by tumble drying in a heated clothes dryer, wherein the article remains with the laundry throughout the entire process.

Claims

1. A particulate, detergent-compatible, dryer-activated, quench cooled fabric softener composition comprising at least about 10% of a cationic fabric softener, the said softener composition having a melting point of from about 40°C to about 80°C, and wherein an average of said particulate particles has a smooth surface, said smooth surface being at least about 10% of the total surface of said average particle.

2. The detergent-compatible, dryer-activated, quench cooled fabric softener composition of Claim 1 in particulate form, the said particles comprising:
(a) from about 70% to about 100% of said particulate fabric softener composition comprising at least about 10% of said cationic fabric softener; and
(b) from 0% to about 30% of a coating surrounding said particulate, said coating being a substantially water-­insoluble material having a melting point above about 35°C and a penetration value of about 0.6 mm or less as measured by ASTM Test D-1321 modified by using a 100 gram weight;
wherein said particles having a size range selected from about 100 to 5,000 microns, 300 to 3,000 microns, and 500 to 2,000 microns and wherein said fabric softener composition has a differential penetration value of at least about 0.1 mm less than a comparable nonquenched fabric softener as measured by ASTM Test D-1321, modified by using a 100 gm weight.

3. The quench cooled fabric softener composition of Claim 2 wherein said fabric softener composition has a differential penetration value of at least 0.2 mm less than said nonquenched fabric softener.

4. The quench cooled fabric softener composition of Claim 1 wherein the cationic softener is of the formula
[R₁R₂R₃R₄N]⁺Y⁻
wherein one or two of the R₁, R₂, R₃ and R₄ groups is an organic radical containing a group selected from C₁₂-C₂₂ aliphatic radicals having from 10 to 16 carbon atoms in the alkyl chain and alkylbenzyl radicals having from 10 to 16 carbon atoms in the alkyl chain, the remaining groups being selected from C₁-C₄ alkyl, C₂-C₄ hydroxyalkyl, and cyclic structures in which the nitrogen atom in the formula forms part of a ring, and wherein Y⁻ is an anionic radical, and wherein the cationic softener com­prises from about 10% to about 50% of the softener composition, and wherein the coating (b) comprises from about 3% to about 15% of said particle.

5. A process for making a detergent-compatible, dryer-activated fabric softener composition comprising the steps of:

1. forming a molten fabric softener composition;

2. intimately contacting said molten fabric softener com­position with cooling device; and

3. quenching said molten fabric softener to a temperature low enough to solidify said molten fabric softener within from about 1 second to about 60 seconds.

6. The process of Claim 5 wherein said molten fabric softener has a temperature selected from about 40°-100°C and 45°-80°C; said quenching temperature is selected from temperatures of about 4°-38°C and 10°-30°C, and combinations thereof and said quenching time is from about 20 seconds to about 40 seconds.

7. The process of Claim 6 wherein said quenching is done by casting the molten fabric softener on a cooling device selected from moving cooled belts and chilled rolls, wherein said cooling device has a temperature zone having a temperature range selected from about 32-38°C, 20-32°C, 10-20°C, and combinations thereof, and wherein said casted molten fabric softener is cast in a form selected from sheets, ribbons, pastilles, spray granules or screen printed particles.

8. A quench cooled fabric softener composition made according to the process of Claim 7.

9. A product comprising a water-insoluble, water-permeable pouch and a particulate dryer-activated quench cooled fabric softener composition contained in said pouch.

10. The product according to Claim 9 wherein said pouch also contains a laundry wash cycle component selected from detergents and bleaches.

11. A detergent-compatible, dryer-activated, quench cooled fabric softener composition comprising at least about 10% of a cationic fabric softener, the said softener composition having a melting point of from about 40°C to about 80°C, and a differential scanning calorimetry curve more complex than that of a compar­able nonquenched fabric softener.