LIQUID DETERGENTS AND CLEANING SOLUTIONS: BUILDER THEREFOR

Abstract: Quaternary ammonium silicates of certain composition and structure are useful ingredients for cleaning solutions and liquid laundry detergents. Such silicates wherein the organic ammonium cation has a molecular weight of less than about 240 can be formulated with surfactants to provide stable liquid detergent solutions that exhibit excellent cleaning when compared to commercial products.

Description: LIQUID DETERGENTS AND CLEANING SOLUTIONS: BUILDER THEREFOR Background of the Invention This invention relates to cleaning solutions, especially liquid laundry detergents. In particular, the invention involves quaternary ammonium silicates as builders or co-builders for liquid cleaners and laundry detergents. Formulation problems primarily associated with laun- dry detergents have changed over the years as a result of the development and availability of raw materials, govern¬ ment regulations, and public taste and acceptance of such products. One of the most important problems associated with laundering and laundry products is water hardness and its geographic variability. Hard water contains calcium and magnesium ions that inhibit the action of most surface active agents included in the formulation to perform the greatest portion of the cleaning job. The usual way of combating hard water is to include a builder in the formulation. Such builders function by reducing or elimi¬ nating the activity of calcium and/or magnesium ions but do not interfere with detersive action if said ions are not present. Initially these builders were precipitants—they reduced the activity of calcium and magnesium ions by precipitation from the washing bath. The activity of the hard water ions was effectively reduced, but the precipi¬ tated salts deposited onto fabrics, turning white fabrics grayish. The complex phosphates essentially displaced the earlier builders since they sequester the calcium and magnesium and maintain the resulting inactive complex in solution so that deposits do not form on clothes. Phosphates remained the builder of choice for many years, since they provided powder detergent with excellent cleaning properties. Liquid detergents that were built with phosphates were developed as taught in U.S. Patents 3,001,945; 3,066,104 and 3,208,947. These products could not compete with phosphate built powders. Recently many factors have changed washing practices and detergent formulations. These include new fabrics, new raw materials, higher energy costs, and government regula- tions of phosphate discharge into the environment. In this changing marketplace, liquid detergents have been competing successfully with detergent powders. The compositions of these liquid detergents are limited, because producing relatively stable systems with a number of components has proved difficult. In general, these systems do not contain builders, or they contain ex¬ pensive organic sequestering agents such as sodium citrate. In addition, other ingredients known as hydrotropes may be required to stabilize the liquids. These combinations are expensive and increase to some degree the BOD load on water treatment facilities. In addition, the incorporation of silicate for corro¬ sion control, for sequestration of magnesium ions, and as a source of alkalinity has been very difficult because of stability problems. U.S. Patents 3,935,192 and 4,388,205 teach the inclusion of silicates in liquid compositions of either very high pH or very complex, expensive composition. It is an object of this invention to provide organic silicates that have not previously been used in detergents and that provide stable liquid detergents and cleaning solutions. It is another object of this invention to pro¬ vide combinations of silicates that provide competitive building and cleaning power for detergents. Further objec¬ tives of this invention are to provide liquid detergents and cleaning solutions that utilize these silicates in less com¬ plex formulations and that provide corrosion protection. Summary of the Invention We have found that certain quaternary ammonium silicates have structures that differ from alkali metal silicates sufficiently to allow formulation of less complex liquid detergents and cleaning solutions. These silicates that contain 0.8 to 5.0 moles of Si0 2 per mole of Q 0 (Q = quaternary ammonium ion) can be formulated with combi¬ nations of surfactants and other detergent ingredients without the need for expensive hydrotropes. If appropriate hydrotropes are included in the composition, the ingredients and amounts of ingredients can vary more widely. For example, a higher level of silicate can be used in the detergent. The silicates that provide such stable liquid detergents have compositions wherein Q has a molecular weight of less than 240. These silicates provide builder properties by enhancing the performance of the surfactants. They can be formulated with organic sequestering agents as co-builders. A combination of sodium and/or potassium sili¬ cate and the quaternary ammonium silicate also provides excellent detergent properties. The liquid detergents or cleaners of our invention containing our limited number quaternary ammonium silicates use water as the solvent and/or continuous phase. Some undissolved materials may be suspended in the liquid, espe- cially if the material is thickened. Non-aqueous liquids can also be used as the solvent and/or continuous phase. Liquid surfactants can be used, and our selected quaternary ammonium silicates are compatible with such systems. The Invention The organic ammonium silicates useful in detergents and cleaners, especially liquid detergents and/or cleaning solutions, are of limited composition when considering the class of such organic silicates. U.S. Patents 3,239,521; 3,301,853; 3,346,334 and 3,383,386 disclose a broad range of organic ammonium silicates. These silicates have not been formulated into stable liquid detergents and/or cleaning solutions. Organic ammonium silicates that do form stable liquid detergents that are effective cleaning materials should contain 0.8 to 5.0 moles of Si0 2 for each mole of O-O. The composition of Q is important in providing the desired silicate. Its structure is as follows: Q = R n ' n , (CH 2 CH 2 OH) 4 _ (n + n , )N + When R and R' are methyl or ethyl, n + n' can be 0 to . If R is propyl, isopropyl or butyl n is 1 and n' must be 0. In general, the molecular weight of Q is less than about 240. The materials are available, as the hydroxides, as articles of commerce, or can be prepared by numerous well known syntheses such as the ethoxylation of amines. We do not believe that Q 2 0 exists in nature, but have adopted the convention used in the silicate industry of expressing the silicate compositions as oxides. The silicate is formed by dissolving a source of silica in the quaternary ammonium hydroxide. In general, nearly pure silica sources with associated water that dissolve in the hydroxide and equilibrate quickly are the most desirable. Silica gels made by neutralizing or partly neutralizing sodium or potassium silicate solution are very useful. Sodium or potassium silicates that have been partially or completely de-alkalized by methods such as ion exchange are also useful. We prefer to use a silica gel. The quaternary ammonium silicates that conform to these compositional requirements provide stable cleaning solutions or liquid detergents when combined with surfactants and other detergent ingredients. We consider a detergent stable if it passes all the tests accepted by the manu¬ facturers of such products. The detergent must be stable under storage at room temperature for one year. It must be stable for one month at 50°C or two months at 40°C and for a minimum of 4 months at 1.7 to 4.4°C. The liquid detergent must also be stable for seven freeze/thaw cycles. Each cycle involves 24 hours at -15°C and 24 hours at room temperature. Stability is evident if there is no phase separation, pre¬ cipitation or haze formation. We have found that sodium and potassium silicate solutions do not pass these tests, and that quaternary ammonium silicates that do not have the compositions des¬ cribed hereinbefore do not form stable liquid detergents or components thereof. In addition, we have found that certain levels of Si0 2 in the detergent are required for stability when hydrotropes are not included in the formulation. Essentially Si0 2 levels of 2.0 to 4.5% by weight provide the most stable liquids. At SiO„ levels less than about 2.0% the detergents failed at least one test. At SiO ? levels of more than about 4.5% the detergent is unstable. If the liquid detergent does contain a hydrotrope to provide additional stability, Si0 2 levels up to about 10% can be stable. The quaternary ammonium silicates of our invention provide builder properties in that they enhance the cleaning surfactants in water that contains ions of calcium and magnesium. The silicates of our invention provide such enhancement even though they have not been found to seques- ter calcium and/or magnesium ions. Indeed, the quaternary ammonium silicates do not appear to reduce the activity of calcium or magnesium ions in solutions in any way. Despite this lack of sequestering power, combinations of nonionic and anionic surfactants with the quaternary ammonium sili- cate provide cleaning that is competitive with a combination of the same surfactant system and sodium citrate, a known sequestrant. We therefore define "builder" as, "any mate¬ rial that provides enhancement of surfactant performance," and as such, we consider quaternary ammonium silicates to be builders. Combinations of the quaternary ammonium silicate and other materials that do reduce the activity of hard water ions such as calcium and magnesium in solution can be added to liquid detergents with advantage. Any material that can reduce these activities, and can be made stable with the surfactants of choice, can be used. Since reduced amounts of such co-builders can be used, some materials previously thought to be unsuitable because of stability problems at effective levels can be used. Inorganic phosphates that are stable along with organic sequestering agents provide desir¬ able combinations. Especially useful are the various salts of ethylinediaminetetroacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acid, citric acid, tartrate succinates and polyacetyl carboxylates. Aluminosilicate ion exchange materials are also useful when they are maintained in suspension. The surfactants useful with the quaternary ammonium silicate of our invention are any that form stable solutions upon combination with our quaternary ammonium silicate, remain stable in storage, and provide the desired cleaning level. We have found nonionic, anionic and combinations thereof to be useful. Zwitterionic and cationic surfactants can be included. Useful nonionic surfactants can be produced by condensing an alkylene oxide such as ethylene oxide with aliphatic or alkyl aromatic compounds. The important property is to balance the hydrophilic and hydro- phobic properties to provide stability and cleaning. The useful anionic surfactants include linear straight chain alkyl benzene sulfonates which are often called LAS materials, ether sulfates and alkyl benzene sulfonates that may have branched carbon chains. The quaternary ammonium silicates of our invention also provide corrosion resistance that has not been avail- able with most liquid detergents previously. Bleach stability is also enhanced by the inclusion of our silicates in such detergents. The relatively simple liquid detergent formulations that include our quaternary ammonium silicate can have lower pH values and allow the use of enzymes that had not been possible in the prior art. Essentially, the use of the quaternary ammonium silicate of our invention allows full formulation of a heavy duty liquid laundry detergent that had not been possible previously. The liquid detergents containing the quaternary ammonium silicate of our invention are about equal in laun¬ dering performance to commercially marketed liquid detergents. Several of these quaternary ammonium silicates crystallize to form solids at specific mole ratios. These materials can be used as components of powdered or granular detergents that are dry blended or agglomerated. Examples The following examples illustrate certain embodiments of our invention. These examples are not provided to estab¬ lish the scope of the invention, which is described in the disclosure and recited in the claims. The proportions are in parts by weight (pbw), percent by weight (% wt/wt) or parts per million (ppm) unless otherwise indicated. The quaternary ammonium silicates used in the fol¬ lowing examples were prepared by mixing silica hydrogel (34% Si0 2 ) with the various quaternary ammonium hydroxide solutions at room temperature. The silica gel dissolved to form water clear solutions. The compositions of these sili¬ cate solutions were 2 to 8 moles of Si0 2 for each mole of Q_0. They contained about 10 to 17% SiO_. The stability tests were carried out by preparing a skeleton detergent formulation of the components which are most difficult to maintain in a stable liquid. We define a stable liquid for cleaners and detergents as one that pro¬ vides a clear solution upon synthesis and is stable (does not exhibit phase separation, precipitation or haze) for at least: l year at room temperature (1) 1 month at 50°C or 2 months at 40°C (2) 3 months at 3.0 1.5°C (3) 7 freeze/thaw cycles of 24 hours at (4) -15°C and 24 hours at room temperature Our skeletal detergent formulation comprises: Anionic surfactant (linear alkyl sulfonate) 16.5% Nonionic surfactant (Neodol 25-7 from Shell) 7.5% Quaternary ammonium silicate (or sufficient ~20.0% to provide the desired level of Si0 2 ) Water Balance to 100.0% Example 1 Detergents formulated with various ratios of tetra- methy1ammonium silicate were tested for stability. The results are as follows: Table 1 Pass means that all four stability requirements were met. These results indicate that detergents formulated with [(CH 3 )- ] 2 0 silicate provide stability at about 3% sio 2 . Example 2 Detergents formulated with trimethylethanol-ammonium silicate, methyltriethanol-ammonium silicate and dimethyl- diethyl-ammonium silicate were tested for stability with the following results: Table 2 Example 3 Detergents formulated with dimethyldiethanol-, trimethylethyl- and methyltriethyl-ammonium silicate and sodium silicates were tested for stability with the following results: Table 3 Quaternary Mole Ratio Ammonium Ion (Si0 2 /Q 2 0 Si0 2 Stability or Sodium or a 2 0) (%) (1) (2) (3) (4) (CH 3 ) 2 (CH 2 CH 2 0H) 2 N+ (CH 3 ) 2 (CH 2 CH 2 OH) 2 N+ (CH 3 ) 3 (CH 2 CH 2 )N+ Na + Na + These results indicate that silicates that do not have structures conforming with that described hereinbefore do not form stable detergents under the conditions tested. Example 4 Detergents were formulated with tetramethylammonium silicate solution and sodium or potassium silicate solution. The results are as follows: Table 4 Tetramethyl ammonium Sodium Silicate Silicate Stability (%) (%) (1) (2) (3) (4) 15.1 1.6 Pass 12.4 3.1 Pass 9.8 4.7 (2) (4) 7.1 6.3 (2) (3) (4) Tetramethyl ammonium Potassium Silicate Silicate (%) <%) 15.1 2.1 12.4 4.3 9.8 6.4 7.1 8.6 These results indicate that some mixtures of quaternary ammonium silicates and alkali metal silicates provide stable liquids, but that if the proportion of inorganic alkali metal is too high instability results. Example 5 Several detergents formulated with silicates of our invention and a commercial product were tested for launder¬ ing efficiency using a Terg-o-tometer. The conditions were as follows. 1. Hardness levels of 150 and 90 ppm were used for washing and rinsing baths. 2. Washing and rinsing were carried out at 105°F. 3. Three types of cloth were used: cotton, polyester and a blend of cotton and polyester. These had standard soils of clay and dust sebum. Clean cloths were used to test redeposition. * 5 4. One and one-half grams of each detergent were used in 1 liter of water for 15 swatches of cloth (2 swatches each of 3 types of cloth and 2 types of soil with 1 clean swatch of each type of cloth) . 1 0 5. Washing time was 10 minutes and rinsing time was 5 minutes. 6. The cloth swatches were ironed on removal from the rinse 15 bath while being protected from contamination. They were allowed to dry overnight while being protected from contamination. 7. Reflectance numbers for the front and back of each 20 swatch of cloth (washed and unwashed) were obtained using the tristimulus L. scale of a Hunter colorimeter. The results, expressed as the average of the changes in reflectance (ΔL) for identical soil-fabric combinations, 25 are summarized in Table 5. These results indicate that liquid commercial detergents wherein the builder sodium citrate has been omitted and a quaternary ammonium silicate of our invention substituted provide satisfactory cleaning when compared to said commercial detergent. 30 35 Table 5 Average Hunter Reflectance Readings ( h) Hard- Cotton Builder Type ness Clean Clay Dust Poly- Poly- Grand Mole SiO /Mole Q 0 (ppm) Cloth Soil Sebum Cotton ester ester Total Comments <- *• Sodium citrate 90 -2.95 37.75 23.25 11.48 23.43 23.15 58.05 Commercial detergent Sodium citrate 90 -2.25 40.75 21.82 13.68 24.30 22.55 60.33 Commercial detergent 4 Siθ2/[(CH 3 ) 4 N] 2 0 90 -3.20 38.90 18.72 10.98 22.45 21.00 54.43 pH of wash water 10.12 4 Si0 2 /[(CH 3 ) N]2θ 90 -1.80 39.38 22.70 15.23 23.93 21.13 60.28 pH of wash water 10.38 NaOH added Si0,/[CH,(CH CH,0H) N] ^ 0 90 -2.20 38.10 21.65 13.20 23.25 21.10 57.55 pH of wash water 10.47 2 3 2 2 3 -2 NaOH added 4 SiO [CH 3 (CH 2 CH 2 OH) 3 N] 2 0 90 -2.80 37.35 18.30 10.33 21.83 20.70 52.85 pH of wash water 10 3.88 Si0 2 /[CH 3 ) 4 N] 2 0 + Na 2 0 90 -2.55 38.55 17.30 11.17 22.95 21.88 55.30 Sodium silicate added t the quaternary ammonium silicate 4 Si0 2 [CH 3 ) 4N ] 2 0 + K 2 0 90 -2.95 40.12 18.8 11.9 22.97 21.10 55.98 Potassium silicate adde to the quaternary ammo¬ nium silicate Notes: 1. The entry in each column is the sum of the SL scores for all appropriate items in the wash load. 2. Each item is included in two categories, soil and fabric types, so that the sum across the columns is twio the grand total. Example 6 The corrosion protection afforded by a tetramethyl- ammonium silicate was tested as follows. Aluminum coupons were submerged in 1% NaOH at room temperature. Gassing developed in a short period of time. Then the silicate of our invention that contained 3.9 moles of Si0 2 per mole of Q_0 was added slowly until gassing stopped. The amount of silicate required provided 2.7% Si0 2 which is in the range of silica required to provide stable liquid formulations. Example 7 The laundering efficiency of various surfactants with the silicates of our invention were tested using a Terg-o- tometer as described in Example 5. The hardness level was 90 ppm. The level of surfactants used was 0.0393% of the washing bath. The tetramethyl ammonium silicate (4Si0 2 /Q 2 0) was added at 0.026% of the washing.bath. The results for a nonionic surfactant (octyl phenoxy polyethoxy ethanol) are summarized in Table 6. These results show that the addition of the silicate of our invention to the nonionic surfactant provides improved cleaning in most categories. If an anti- redisposition agent were added to this formulation, the improvement provided by the quaternary ammonium silicate would be even greater. The results for an anionic surfactant (C 1.2-,-C1,5..-linear primary alcohol ethoxy sulfate ammonium salt) are summarized in Table 7. These results indicate that the addition of the silicate of our invention to the anionic surfactant provides improved cleaning in most categories. If an antiredisposi- ion agent were added to this combination, the improvement provided by the quaternary ammonium silicate would be even greater. Table 6 Ingredien (s) Surfactant Surfactant + 4Si0 2 [(CH 3 ) 4 ] Table 7 Average Hunter Reflectance Readings (ΔL) Ingredient(s) Surfactant -1.88 41.34 16.02 13.07 21.22 20.36 55.49 Surfactant + 4Si0 2 [(CH 3 ) 4 N] 2 0 -5.25 41.59 21.81 13.08 23.12 21.95 58.15 Notes: 1. The entry in each column is the sura of the L scores for all appropriate items in the wash load. 2. Each item is included in two categories, soil and fabric types, so that the sum across the columns is twice the grand total. Example 8 The laundering efficiency of another nonionic sur¬ factant with the silicate of our invention and Zeolite A Table 8 Average Hunter Reflectance Readings (SL) Clean Clay Dust Cotton Grand Ingredient(s) Cloth Soil Sebum Cotton Polyester Polyester Total Surfactant + 4Si0 2 [(CH 3 ) 4 N] 2 0 -4.20 40.05 21.22 12.22 22.24 22.16 56.80 Zeolite A -2.48 40.56 21.05 12.48 23.22 23.41 59.12 Surfactant + 4Si0 2 [(CH 3 ) 4 N] 2 0 -2.42 41.55 22.39 12.86 24.28 24.39 61.53 + sodium citrate Table 9 Average Hunter Reflectance Readings (ΔL) Clean Clay Dust Cotton Grand Inqreflient(s) Cloth Soil Sebum Cotton Polyester Polyester Total LAS + 4 Si0 2 [(CH 3 ) 4 N] 2 0 - 8.05 28.00 2.00 0.88 12.05 9.02 21.95 Zeolite A -10.00 34.13 3.28 2.30 13.95 11.15 27.40 Notes: 1. The entry in each column is the sum of the L scores for all appropriate items in the wash load. 2. Each item is included in two categories, soil and fabric types, so that the sum across the columns is twice the grand total.

Claims: Claims We claim: 1. A composition useful as an ingredient in cleaning and detergent solutions comprising an organic ammonium sili¬ cate that contains 0.8 to 5.0 moles of Si0 2 for each mole of Q 2 0 wherein: Q = R n (CH 2 CH 2 OH) 4 _ (n + n , )N + R and R' are methyl or ethyl, n + n' is 0 to 4, and Q has a molecular weight of less than 240. 2. A composition useful as an ingredient in cleaning and detergent solutions comprising an organic ammonium sili¬ cate that contains 0.8 to 5.0 moles of Si0 2 for each mole of Q 2 0 wherein: Q = R n R' n . (CH 2 CH 2 0H) 4 _ (n + nI) N + R is propyl, isopropyl or butyl, n is 1 and n' is 0, and Q has a molecular weight of less than 240. 3. A detergent or cleaning solution that comprises a surfactant and an organic ammonium silicate that contains 0.8 to 5.0 moles of Si0 2 for each mole of Q 2 0 wherein: Q - R n R < CH 2 CH 2 OH >4-(n + n') N π R and R' are methyl or ethyl, n + n' is 0 to 4, and Q has a molecular weight of less than 240. 4. The detergent or cleaning solution of claim 3 wherein the organic ammonium silicate provides about 2.0 to 4.5% by weight of Si0 2 . 5. The detergent or cleaning solution of claim 3 wherein the surfactant is anionic, nonionic or a mixture thereof. 5 6. The detergent or cleaning solution of claim 4 wherein the surfactant is anionic,. nonionic or a mixture thereof. 7. A detergent or cleaning solution that comprises 0 surfactant, a sodium or potassium silicate and an organic ammonium silicate that contains 0.8 to 5.0 moles of Si0 2 for each of mole of Q 2 0 wherein: Q = R n R V < CH 2 CH 2 0H >4-(n + n') N 5 R and R' are methyl or ethyl, n + n* is 0 to 4, and Q has a molecular weight of less than 240. 8. The detergent or cleaning solution of claim 7 0 wherein the surfactant is anionic, nonionic or a mixture thereof. 9. The detergent or cleaning solution of claim 7 wherein the organic ammonium silicate provides about 2.0 to 5 4.5% by weight of Si0 2> 10. A detergent or cleaning solution that comprises a surfactant, a hydrotrope and an organic ammonium silicate that contains 0.8 to 5.0 moles of Si0 2 for each mole of Q of Q 2 0 wherein: Q = R n R V < CH 2 CH 2 0H >4-(n + n') N+ R is propyl, isopropyl or butyl, n is 1, n' is 0, and Q has a molecular weight of less than 240. 11. The detergent or cleaning solution of claim 10 wherein the organic ammonium silicate provides about 2.0 to 10% by weight of Si0 2 . 12. The detergent or cleaning solution of claim 10 wherein the surfactant is anionic, nonionic or a mixture thereof. 13. The detergent or cleaning solution of claim 11 wherein the surfactant is anionic, nonionic or a mixture thereof.

Inventors: BOYCE SCOTT DANIEL, COFFEY RICHARD THOMAS, KRUMRINE PAUL HENRY, MORRIS TIMOTHY CHRISTOPHER, SIMMONS JOHN ANTHONY, ZEFFERI SUZANNE MARIE, BOYCE, SCOTT, DANIEL, COFFEY, RICHARD, THOMAS, KRUMRINE, PAUL, HENRY, MORRIS, TIMOTHY, CHRISTOPHER, SIMMONS, JOHN, ANTHONY, ZEFFERI, SUZANNE, MARIE
Applicants: PQ CORP, PQ CORPORATION
Application year: 1990
Main classification: C11D
IPC codes: C11D3, C11D17