Liquid detergent fabric softening laundering composition

Abstract: A liquid detergent having fabric softening properties and including an improved fabric softening agent. The fabric softening agent is a silicone fabric softening agent selected from the group consisting of a polyorgano­ siloxane which is free of reactive organic functional groups and having a viscosity in excess of about 5,000 centistokes measured at 25°C.; a polydiorganosiloxane gum having a viscosity of about two million centistokes; or a mixture of the said gum with either a low viscosity polydiorganosiloxane or with a volatile cyclic silicone such as octamethylcyclo­ tetrasiloxane or decamethylcyclopentasiloxane. Certain emulsions of a highly branched and cross-linked silicone polymer may also be employed.

Description: This invention relates to a liquid detergent having fabric softening properties and including at least one fabric softening agent. The improvement involves the use of a silicone fabric softening agent selected from certain polydiorganosiloxane gums having a viscosity in excess of 1m²/s (one million centistokes) measured at 25°C, mixtures of at least one volatile cyclic silicone and said polydiorganosiloxane gum, and mixtures of said polydiorganosiloxane gum and a low viscosity polydiorganosiloxane with a viscosity of 10⁻⁴m²/s (100 cs.). Accordingly, the present invention provides a liquid laundry detergent having fabric softening properties and including at least one fabric softening agent a surfactant and a carrier fluid, characterised in that said detergent comprises 0.5 to 5 wt % of a silicone fabric softening agent selected from polydiorganosiloxane gums having a viscosity greater than 1m²/s (1,000,000 cs) at 25°C., and having an average unit formula: R a 3 SiO 4-a 2 wherein each R³ is a monovalent radical selected from methyl, vinyl, phenyl, ethyl and 3,3,3-trifluoropropyl radicals and a has an average value of 1.95 to 2.005, inclusive, at least 90 percent of the total R³ groups being methyl radicals and molecules of said polydiorganosiloxane gums being terminated by a group selected from silanols, alkoxys and R 3 3 SiO 0.5 , where R³ is as defined above; mixtures of at least one volatile cyclic silicone and a polydiorganosiloxane gum as defined above; and a mixture of a polydiorganosiloxane gum as defined above and a low viscosity polydiorganosiloxane having a viscosity of about 10⁻⁴m²/s (one hundred centistokes), and in that said surfactant comprises at least one anionic surfactant and at least one non-ionic surfactant, optionally together with a cationic surfactant, the ratio of said anionic surfactant to said non-ionic surfactant being in the range of from 4:1 to 1:4. The invention also provides a method of washing a textile fabric which comprises the step of adding to said fabric 0.05-0.3 percent, by weight based on the weight of fabric, of a detergent as defined in any of claims 1 to 9. The Invention further provides a method of making a detergent as claimed in any of claims 1 to 9, wherein said silicone fabric softening agent is first mixed with the acid form of said anionic surfactant and the resulting mixture of anionic surfactant and silicone is neutralized by the addition of a base before being admixed with the balance of the liquid detergent formulation, including said non-ionic surfactant. In some of the more preferred embodiments of the present invention, the volatile cyclic silicone constitutes about 90-70 percent by weight based on the total weight of the silicone mixture. The volatile cyclic silicone must be sufficiently volatile to evaporate at room temperature and exemplary materials are octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane or mixtures thereof. The detergent also includes a carrier fluid such as water, ethanol, isopropanol, butanol, hexanol, propylene glycol or diethylene glycol. The detergent further includes at least one anionic surfactant and at least one non-ionic surfactant. A cationic surfactant may also be included. The ratio between the anionic surfactant and the non-ionic surfactant is 4:1 to 1:4, more preferably from about one to one to about three to one. The detergent should include on a weight basis at least 0.5-5.0 percent of the silicone fabric softening agent. The detergent is employed in an amount of 0.05-0.3 percent by weight based on the weight of textile fabric being treated. While the liquid detergent of the present invention may contain many of the commonly included ingredients such as surfactants, builders, enzymes and enzyme stabilizers, pH modifiers, bleach activators and bleaches, antifoams, antiredeposition agents, chelants, soil release polymers, dye transfer protectants, zeolite dispersants, water softeners, perfumes, anti-oxidants and fluorescent brighteners, the essential ingredients for the purposes of the present invention are an anionic surfactant, a non-ionic surfactant, a carrier fluid and a softening agent as defined above. Water is a suitable carrier although other fluids such as ethanol, isopropanol, butanol, hexanol, propylene glycol or diethylene glycol may be employed. The softening agent as noted above, is a silicone and may include at least one of a polydiorganosiloxane gum as defined above having a viscosity greater than 1m²/s (1,000,000 centistokes) at 25°C°., e.g., about 2m²/s (two million centistokes) at 25°C., or an admixture of said polydiorganosiloxane gum together with about 95-70 percent by weight of a volatile cyclic silicone. These materials will be described in detail hereinafter. The liquid detergent contains at least one surfactant and the surfactants for purposes of the present invention are of the non-ionic and anionic surfactant type. In non-ionic surfactants, for example, there is no charge on the molecule and the solubilizing groups are ethylene oxide chains and hydroxyl groups. Such non-ionic surfactants are compatible with ionic and amphoteric surfactants and representative of non-ionic surfactants are, for example, polyoxyethylene or ethoxylate surfactants, such as alcohol ethoxylates and alkylphenol ethoxylates. Carboxylic acid ester non-ionic surfactants include glycerol esters, polyoxyethylene esters, anhydrosorbitol esters, ethoxylated anhydrosorbitol esters, natural fats, oils and waxes and ethoxylated and glycol esters of fatty acids. Carboxylic amide non-ionic surfactants which may be included are diethanolamine condensates, monoalkanolamine condensates and polyoxyethylene fatty acid amides. Representative of polyalkylene oxide block copolymer non-ionic surfactants are the polyalkylene oxides derived from ethylene, propylene, butylene, styrene and cyclohexene. Typical of the anionic surfactants that are employed herein are salts of alkyl sulfates, salts of alkylaryl sulfates, salts of alkyl ether sulfates, salts of alkylaryl ether sulfates and salts of alkylaryl sulfonates. Exemplary materials included are, for example, alkyl benzene sulfonates, alkyl glyceryl ether sulfonates, alkyl phenol ethylene oxide ether sulfates, esters of alpha-sulfonated fatty acids, 2-acyloxyalkane-1-sulfonic acids, olefin sulfonates, beta-alkyloxyalkane sulfonates, anionic surfactants based on higher fatty acids and tallow range alkyl sulfates. Both categories of surfactant are well known in the art and are described, for example, in U.S. Patent No. 4,075,118. Conventional cationic surfactants may also be included, if desired. The polydiorganosiloxane gums suitable for use in the present invention are for the most part polydimethylsiloxane gums. The polydiorganosiloxane gums are represented by an average unit formula: R a 3 SiO 4-a 2 where each R³ is a methyl radical, a vinyl radical, a phenyl radical, an ethyl radical or a 3,3,3-trifluoropropyl radical, and a has an average value of 1.95 to 2.005 inclusive. Since the polydiorganosiloxane gums are essentially polydimethylsiloxane gums, at least 90 percent of the total R³ groups are methyl radicals and the remaining R³ groups are vinyl, phenyl, ethyl or 3,3,3-trifluoropropyl. Small amounts of other groups may be present such as 1 or 2 percent of the total R³, where such groups are other monovalent hydrocarbon groups, such as propyl, butyl, hexyl, cyclohexyl, beta-phenylethyl or octadecyl; other halogenated monovalent hydrocarbon radicals, such as chloromethyl, bromophenyl, α,α,α-trifluorotolyl, perfluoroheptylethyl or dichlorophenyl; cyanoalkyl; alkoxyl, e.g., methoxy, propoxy, ethoxy or hexoxy; ketoxime; halogen; hydroxyl; or acyloxy. The groups which are present in small amounts are considered as incidental and not producing any significant characteristic changes of the polydimethylsiloxane gum. The polydiorganosiloxane gums suitable for the present invention are essentially composed of dimethylsiloxane units with the other units being represented by monomethylsiloxane, trimethylsiloxane, methylvinylsiloxane, methylethylsiloxane, diethylsiloxane, methylphenylsiloxane, diphenylsiloxane, ethylphenylsiloxane, vinylethylsiloxane, phenylvinylsiloxane, 3,3,3-trifluoropropylmethylsiloxane, dimethylphenylsiloxane, methylphenylvinylsiloxane, dimethylethylsiloxane, 3,3,3-trifluoropropyldimethylsiloxane, mono-3,3,3-trifluoropropylsiloxane, monophenylsiloxane or monovinylsiloxane. The polydiorganosiloxane gums are well known in the art and can be obtained commercially and are considered to be insoluble polydiorganosiloxanes which have viscosities greater than 1m²/s (1,000,000 cs.) at 25°C., preferably, greater than 2m²/s (2,000,000 cs.) at 25°C., more preferably, greater than 5m²/s (5,000,000 cs.) at 25°C. These gums may be used alone as well as in admixture with one or more volatile ingredients such as a cyclic silicone. Volatile cyclic silicones which may be employed are polydimethylcyclosiloxanes exemplary of which are octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. The viscosity at 25°C. of the volatile cyclics is generally of the order of 2.5x10⁻⁶ to 6.0x10⁻⁶ m²/s (2.5 to 6.0 cs). Such volatile ingredients are generally represented by the formula (CH₃)₂SiO x where x is 3-8. When used in admixture with the gum, the level of the cyclic is generally of the order of about thirteen percent by weight. The following examples are set forth in order to illustrate the concepts of the present invention. Example I In accordance with the present invention, silicones were emulsified in a detergent matrix by first mixing the silicone with the acid form of an anionic surfactant such as a linear alkyl benzene sulfonic acid. The mixture of the anionic surfactant and the silicone was neutralized by the addition of a base such as sodium hydroxide in a mixture of water and ethanol. The salt of the anionic surfactant results from this neutralization. Following completion of the neutralization, the non-ionic surfactant was added, together with other optional ingredients such as builders, fatty acids, cationic surfactants and optical brighteners. The mixture was mechanically agitated in order to insure a homogeneous product. It has been found that, in the event that the foregoing procedure is not followed, the silicone ingredient is caused to separate, thus forming an unstable product. This occurs, for example, by the addition of the silicone to a random mixture of various ingredients as in the procedures of U.S. Patent No. 4,639,321, where, in the examples, an amino-substituted silicone is admixed directly into a liquid composition of some fourteen ingredients under agitation. In accordance with the present invention, the silicone must be first mixed with an anionic surfactant and neutralized prior to being added to the balance of the liquid detergent formulation in order to provide a stable end product. The above procedure was followed and several formulations of liquid detergent containing a silicone softening agent were prepared. In each instance, there was employed twenty weight percent of an anionic surfactant, six weight percent of a non-ionic surfactant, five weight percent of ethanol and three weight percent of a silicone softening agent, the balance being water. The preferred ratio of the anionic surfactant to the non-ionic surfactant is within the range of from 1:1 to 3:1. The anionic surfactant employed was an alkylbenzene sulfonic acid of Vista Chemical Company. The non-ionic surfactant was NEODOL® 25-7, a trademark and product of Shell Chemical Company, Houston, Texas, USA, and a linear primary alcohol. Liquid detergents were prepared containing these ingredients and including one of two silicone softening agents, namely, a polydiorganosiloxane gum having a viscosity of about 2m²/s (two million centistokes); and a mixture of a polydiorganosiloxane gum having a viscosity of about 2m²/s (two million centistokes) and about thirteen weight percent of a volatile cyclic silicone of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane. Example II Towels were prepared for treatment by removing the mill textile conditioners applied at the mill during manufacture of the towels. The process was conducted at a commercial laundromat. Bundles of 86:14 cotton/polyester terry towels were washed five times with an anionic detergent containing a high level of phosphorus. Detergent remaining in the towels was removed by three final wash and rinse cycles from which detergent was omitted. Each bundle was subjected to eight complete wash and rinse cycles during the stripping process, followed by a drying cycle. The test used to measure softness was a panel test in which fifteen people were asked to rank several towels in order of softness. Following treatment, the towels were placed in a constant temperature and humidity room overnight to equilibriate, after which the towels were tested the next day. Dryers tend to overdry towels and to provide a harsher feel than normal, and, therefore, all towels tested in a given panel were conditioned at the same temperature and humidity before testing. Each test included one control towel. The control towel was a towel which had not been treated by a liquid detergent containing a softening agent. The fifteen people were asked to evaluate the towels by feeling the towels and choosing the harshest towel and the softest towel, and placing the remaining towels in order of increasing softness. The towels were assigned a ranking between one and five with the highest value corresponding to the softest towel. Before the test was conducted, each member of the panel was asked to wash his/her hands to remove any residue which might interfere with the test. During the evaluation, the panel members rewashed their hands to remove any softener buildup. Since the softness of a towel increases with repeated handling, a new surface of each towel was exposed for each panel member, and each towel was replaced after evaluation by three people. Example III Each of the liquid laundry detergents containing a silicone softening agent as prepared in accordance with Example I was used to treat a fabric bundle which had been conditioned in accordance with the procedure of Example II. The bundles contained six towels and weighed about 1200-1400 grams. The bundle was loaded into a washing machine and about fifty grams of liquid detergent containing a softening agent were added to the washing machine. The washing machine controls were established to provide a warm water wash (35°C.) and a cold water rinse. The duration of the wash cycle of the particular washing machine employed was about fourteen minutes. At the end of the cycle of the washing machine, the bundle was dried in a dryer for about one hour. Each bundle was exposed to two complete cycles including washing and drying. The bundles were then equilibrated and tested to measure softness as indicated in Example II. The results of the softness test are set forth in Table I hereinbelow. In addition to the silicone softening agents of the present invention, there were also tested softening agents of the prior art for comparative purposes. One softening agent was a commercially employed organic fabric softening agent and a product of Sherex Chemical Company, Dublin, Ohio, USA. The organic softening agent was monohydrogenated tallow trimethylammonium chloride available as a fifty percent by weight active material in isopropanol solvent. This organic softening agent is marketed under the trademark ADOGEN® 441. The comparative softening agent was employed in the same amount to treat the fabric bundles as the silicone softening agents of the present invention, namely, about 0.12 weight percent of active ingredient based on the weight of the bundle. The amount of the softening agent employed may vary from 50-100 grams per load depending upon the particular weight of the bundle being treated. Softening Agent Average Rank Polydiorganosiloxane gum, viscosity of about 2m²/s (two million centistokes) 3.2 Mixture of volatile cyclic silicone and polydiorganosiloxane gum 3.1 ADOGEN® 441 2.8 Control 1.9 Table I (above) indicates that the two silicone softening agents of the present invention attained an average rank of at least three or more, significantly above the rank attained by the prior art organic softening agent ADOGEN® 441 indicated above, and well above the rank attained by the control. It should be noted that the polydiorganosiloxane gum of the invention may also be employed in the form of a mixture including a low viscosity polydiorganosiloxane with a viscosity of about 10⁻⁴m²/s (one hundred centistokes).

Claims: A liquid laundry detergent having fabric softening properties and including at least one fabric softening agent a surfactant and a carrier fluid, characterised in that said detergent comprises 0.5 to 5 wt % of a silicone fabric softening agent selected from polydiorganosiloxane gums having a viscosity greater than 1m²/s (1,000,000 cs) at 25°C., and having an average unit formula: R a 3 SiO 4-a 2 wherein each R³ is a monovalent radical selected from methyl, vinyl, phenyl, ethyl and 3,3,3-trifluoropropyl radicals and a has an average value of 1.95 to 2.005, inclusive, at least 90 percent of the total R³ groups being methyl radicals and molecules of said polydiorganosiloxane gums being terminated by a group selected from silanols, alkoxys and R 3 3 SiO 0.5 , where R³ is as defined above; mixtures of at least one volatile cyclic silicone and a polydiorganosiloxane gum as defined above; and a mixture of a polydiorganosiloxane gum as defined above and a low viscosity polydiorganosiloxane having a viscosity of about 10⁻⁴m²/s (one hundred centistokes), and in that said surfactant comprises at least one anionic surfactant and at least one non-ionic surfactant, optionally together with a cationic surfactant, the ratio of said anionic surfactant to said non-ionic surfactant being in the range of from 4:1 to 1:4. A detergent in accordance with claim 1, wherein said carrier fluid is selected from water, ethanol, isopropanol, butanol, hexanol, propylene glycol and diethylene glycol. A detergent in accordance with claim 1 or claim 2, in which said polydiorganosiloxane gum has a viscosity of about 2m²/s (2,000,000 cs) at 25°C. A detergent in accordance with claim 1 or claim 2, in which said polydiorganosiloxane gum has a viscosity greater than 2m²/s (2,000,000 cs) at 25°C. A detergent in accordance with claim 4, in which said polydiorganosiloxane gum has a viscosity greater than 5m²/s (5,000,000 cs) at 25°C. A detergent in accordance with any of claims 1 to 5, in which said silicone fabric softening agent is a mixture of said polydiorganosiloxane gum and a volatile cyclic silicone, said silicone being present in said mixture in a proportion of 95-70 percent by weight. A detergent in accordance with claim 6, in which said volatile cyclic silicone is octamethylcyclotetrasiloxane. A detergent in accordance with claim 6, in which said volatile cyclic silicone is decamethylcyclopentasiloxane. A detergent in accordance with any of claims 1 to 8, in which the ratio of the anionic surfactant to the non-ionic surfactant is in the range of from one to one to three to one. A method of washing a textile fabric which comprises the step of adding to said fabric 0.05-0.3 percent, by weight based on the weight of fabric, of a detergent as defined in any of claims 1 to 9. A method of making a detergent as claimed in any of claims 1 to 9, wherein said silicone fabric softening agent is first mixed with the acid form of said anionic surfactant and the resulting mixture of anionic surfactant and silicone is neutralized by the addition of a base before being admixed with the balance of the liquid detergent formulation, including said non-ionic surfactant.

Inventors: DONKERS ANNEMIEKE CONSTANTIA M, MADORE LINDA MOY, DONKERS, ANNEMIEKE CONSTANTIA MARIA, MADORE, LINDA MOY
Applicants: DOW CORNING, DOW CORNING CORPORATION
Application year: 1990
Main classification: C11D3
IPC codes: C11D3, D06M13, C11D17, D06M15