US3509059A - Process of making built liquid detergents containing polymeric dispersing agents - Google Patents

Description

United States Patent US. Cl. 252135 9 Claims ABSTRACT OF THE DISCLOSURE Stable heavy duty liquid detergent compositions which contain high electrolyte content as the-builder component thereof are produced in stabilized form by polymerizing to a polymer a monomer in the presence of the detergent material the latter being present in major amounts, said polymer acting as a stabilizer for said compositions.

This invention relates to the production of polymer compositions and relates more particularly to the production of detergent compositions containing high polymers.

Liquid detergent compositions containing non-ionic surfactants in concentrated aqueous solutions of electrolytes (particularly builder salts, e.g. tetrapotassium pyrophosphate) have been previously suggested. Typically the electrolyte concentration (based on weight of water plus electrolyte) has been 10%. Particularly when the electrolyte concentration is more than about 15-20%, such compositions tend to separate into two distinct layers on standing (called salting out or creaming up), the liquid non-ionic surfactant forming the upper layer, and it has been suggested that this tendency can be reduced by adding to such compositions polymeric dispersing agents, such as sodium polyacrylates. The manufacture of emulsified compositions of this type is, however, difiicult and it is cumbersome readily to obtain highly concentrated detergent compositions.

In accordance with one aspect of this invention, I have found that the polymeric dispersing agent can be formed in situ by polymerization of the corresponding monomer in the presence of non-ionic detergents. This method makes it possible to manufacture readily a highly concentrated mixture of high stability containing a substantial proportion of the polymeric dispersing agent and of electrolytes.

Other aspects of this invention will be apparent from the following detailed description and claims. In this description and claims all proportions are by weight unless otherwise indicated.

The non-ionic detergents are well known in the art. One class of compounds comprises surfactants having alkylene oxide groups which are hydrophilic in nature combined with an organic hydrophobic group. The preferred class includes the ethoxylation products of hydrophobic hydroxyl compounds such as long chain aliphatic compounds and alkylaromatic compounds. Among such materials are the polyethylene oxide condensates of aliphatic alcohols having, for example, 8 or more (e.g. 8-18) carbon atoms, such as lauryl or tallow alcohols, combined with, for example, 3-30 moles of ethylene oxide for each mole of the long chain alcohol.

Other non-ionic detergents are the polyethylene oxide condensates of alkyl phenols, having, for example, an alkyl group of about 6 to 12 carbon atoms (e.g. nonyl phenol) in which there are a plurality of ethylene oxide units (e.g. up to 30) per mole of alkyl phenol. Another class of non-ionic detergents includes the polyethylene oxide condensates of higher glycols, which may be made, for example, by condensing ethylene oxide with a polypropylene glycol made by reacting propylene oxide and propylene glycol, said polypropylene glycol having a molecular weight of 1500-1800. Again, the non-ionic detergent may be made by condensing ethylene oxide with a water-insoluble reaction product (e.g. of molecular weight about 3000) of a diamine (e.g. ethylene diamine) and excess propylene oxide, to incorporate about 40-80% of ethylene oxide in the final condensation product. Ethoxylation products of compounds containing mercapto, rather than hydroxyl, groups may also be used.

The monomer used advantageously comprises a material polymerizable to form a polymer containing a plurality of acidic groups along the polymer chain. Preferred monomeric material includes an ethylenically unsaturated polymerizable compound whose polymers contain salt forming carboxyl groups, e.g. acrylic acid, maleic anhydride, itaconic acid, etc. Monomers containing sulfonic acid groups, e.g. styrene sulfonic acid, may also be employed. The monomeric material may be a single compound, whose polymerization results in the production of a homopolymer, or it may be a mixture of monomeric materials. For example, the polymerization process may be a copolymerization involving a monomer which contains water-solubilizing groups or contains precursors of such groups and a monomer which does not sup ply such groups. Examples of additional monomers are styrene, methyl styrene, vinyl acetate and other vinyl esters, ethyl acrylate, methyl acrylate and other acrylate or methacrylate esters. It will be understood that while monomers which polymerize by addition of unsaturated carbon-to-carbon bonds are preferred, it is within the broad scope of this invention to employ other types of polymerizable monomers. Also, while best results are obtained through the use of acidic salt-forming monomers, it is within the broad scope of the invention to use other monomers, e.g. vinyl acetate, to form polymers containing depending groups which can by suitable reaction (e.g. saponification) be converted to water-solubilizing groups (e.g. by conversion of polyvinyl acetate to polyvinyl alcohol). It is preferable to employ monomers which do not react substantially with the selected detergent during the polymerization reaction; similarly, during the conversion of the initial polymer to its final form as a dispersing agent, it is desirable to employ reaction conditions which do not adversely affect the non-ionic detergent.

The polymerization of the monomeric material advantageously takes place in the presence of an amount of the non-ionic detergent which is greater than the amount of monomer. Advantageously there is used about 8 to 1 parts, and, for maximum stability of the end product, preferably about 4 to 1 parts, of liquid non-ionic surfactant per part of monomer. For ease of handling, the mixture may be somewhat diluted, water being the preferred diluent, since the final detergent composition is generally to be employed in aqueous media. For best results, the degree of dilution is kept low, particularly in view of the fact that the final detergent compositions are intended for use as concentrates, and removal of excess diluent would be impractical. Advantageously the amount of diluent is so low that the soluble ingredients may be added as aqueous concentrates rather than as solids. Amounts of diluent below 40%, preferably about 30% or less, are advantageously employed. In the preferred process the detergent constitutes well over 50% of the weight of the polymerization mixture.

To promote the polymerization reaction suitable polymerization catalysts are advantageously employed. Thus, for addition polymerization of ethylenically unsaturated monomers there may be used a free radical- 3 yielding catalyst such as azo-bis-isobutyronitrile, benzoylperoxide, cumene hydroperoxide or t-butyl peroxy pivalate. These are employed in minor amounts in proportions well known to the art, e.g. in the range of about 0.1 to 3% of the weight of the monomer.

Modifying agents may also be present to insure the formation of a polymer of the preferred linearity and molecular weight. For example, mercaptosuccinic acid, thio glycolic acid, or thio phenol may be used to act as chain transfer agents and limit the length of the polymer chain. Advantageously, the amount of modifying agent is such as to yield a polymer having a molecular weight Well over 1000, preferably about 10,000 or higher, but not so high that the mixture produced by the polymerization is no longer pourable.

- Polymerization may be promoted by the use of elevated temperatures. Usually, the temperature of polymerization will be in the range from about room temperature to about 80 C., preferably in the range of about 60 to 80 C., but higher and lower temperatures may be employed if desired. Of course, it is desirable to avoid temperatures and catalyst concentrations which adversely affect the polymerization and/or the non-ionic surfactant. Conveniently, the temperature is chosen so that the polymerization can take place at atmospheric pressure, but it is within the scope of this invention to use higher or lower pressures.

In the preferred process, the formation of the polymeric dispersing agent takes place in two or more steps, rather than a single step; thus the polymerization reaction results in the formation of the polymeric backbone, or chain, of the polymeric dispersing agent, and the conversion of the polymeric material to the form in which it is most effective as an emulsifier occurs after polymerization.

In the case of the polymers of acidic monomers, this conversion may be carried out by simple salt formation, as by the addition of a suitable base (e.g. sodium, potassium, or ammonium hydroxide or carbonate); elevated temperatures (e.g. in the range of about 40 to 80 C.) may be employed to accelerate salt formation. The incorporation of the builder salt is preferably also delayed until after the polymerization reaction.

Builder salts may be of the types well known to the art, e.g. water-soluble sodium and potassium phosphates, silicates, carbonates, bicarbonates and borates. Alkaline salts are preferred, and phosphates, including polyphosphates and pyrophosphates are particularly suitable, It is often advantageous to include an alkaline silicate with the phosphate salts. Preferred are such sodium and potassium silicates known to be effective as inhibitors of corrosion of washing machines or other metal equipment, in which the detergent compositions are frequently used. The proportion of inorganic electrolyte in the solution may be varied, as desired, e.g. the proportions thereof may be in the range of about 100 to 500% (preferably in the range of about 250 to 350%) based on the weight of non-ionic surfactant. The concentration of the electrolyte (based on the amount of electrolyte plus water) may be, for example, in the range of about 40%, preferably about 35%. The total amount of water in the resulting mixture is advantageously less than about 50%, but larger amounts may be employed for purposes in which a highly concentrated mixture is not needed.

' Other ingredients which may be present in the composition are additives intended to prevent redeposition of soil during washing, such as carboxymethyl cellulose, and hydrotroping agents such as benzene-, tolueneor xylene-sulfonates. Coloring agents, optical bleaches, germicides, and other additives customarily found in such consumer products may also be included.

The following example is given to illustrate this invention further.

EXAMPLE 500 parts of an adduct of a straight chain 14-16 carbon primary alcohol with about 9 moles of ethylene oxide per 1 mol of alcohol were mixed with 0.1 part mercaptosuccinic acid. To this mixture were gradually added during about 24 hours with stirring at temperatures of 74-84 C. (avoiding ecessive temperature rises due to the exothermic polymerization reaction) parts monomeric methacrylic acid and, in three equal increments during such gradual addition, 0.9 part azo-bis-isobutyronitrile polymerization catalyst and 250 parts water, yielding 871 parts of an acidic clear, colorless and highly viscous but still pourable mixture.

parts of the above mixture was then added and thoroughly blended with a preformed mixture, maintained at a temperature of about 80 C., containing 39 parts of a 45% aqueous solution of potassium hydroxide, 600 parts of 21-60% aqueous solution of tetrapotassium pyrophosphate, 10 parts of carboxymethyl cellulose, 25 parts of a 40% aqueous solution of potassium toluene sulfonate and 91 parts of water. After stirring for about 10 minutes, the resulting blend was cooled to 40 C. and there were added thereto 25 parts of a 45% aqueous solution of medium viscosity sodium silicate, 18 parts of a 1% aqueous solution of Polar Brilliant Blue (or other suitable coloring agents), and a small amount of perfume.

Emulsions of the type described in the above example were found to be efficient and convenient cleaning agents. Because these concentrates are easily diluted with water, they are more convenient to clean spots or textiles, sinks, walls, etc. than are solids which need to be specially dissolved prior to use. The concentrated products may, as

seen above, be made with all the ingredients supplied in the liquid state, e-g. as technically available concentrates. Manufacturing is facilitated and the occurrence of cumbersome curds or precipitates during manufacturing is avoided.

While the invention finds its greatest utility in connection with detergents made from non-ionic surfactants, in its broader aspects it can also be used to make compositions containing other surfactants. Such surfactants may be of the well known anionic, cationic or amphoteric types. Examples of anionic detergents are water-soluble salts, particularly alkali metal salts of sulfate esters or sulfonates containing higher aliphatic hydrocarbon radicals of 8 or more carbon atoms (e.g. 8-22 carbon atoms); such as sodium or potassium sulfates of higher alcohols (e.g. sulfates of alkanols such as coco alcohol or sulfates of other higher alcohols such as the higher alkyl phenol-ethylene oxide ether sulfates or the higher fatty acid monoglyceride sulfates or the ethoxylated higher fatty alcohol sulfates), sodium or potassium salts of higher sulfonic acids (e.g. of higher alkylbenzene sulfonic acids such as pentadecyl benzene sulfonic acid, or of isothionate esters of higher fatty acids such as coconut oil fatty acids). Examples of cationic detergents are quaternary ammonium compounds in which there is a quaternary nitrogen atom directly linked to a carbon atom of a hydrophobic radical of at least ten carbon atoms (e.g. a long chain alkyl radical or an alkylaryl radical, in which there are l0'20 carbon atoms), three valences of the nitrogen atom being also directly linked to other carbon atoms which may be in separate radicals (such as alkyl, particularly lower alkyl, or aralkyl radicals) or in a cyclic structure including the quaternary nitrogen atom (as in a morpholine, pyridine, quinoline or imidazoline ring); stearyl trimethyl ammonium chloride being a specific example. I

Examples of amphoteric detergents are tertiary amine oxides having a hydrophobic radical (such as a hydrocarbon radical of l018 carbon atoms) attached to the nitrogen atom (cg. lauryl dimethyl amine oxide). Other examples are amino acids having a similar hydrophobic radical attached to the nitrogen atom of the amino acid (e.g., N-lauryl aminopropionic acid).

Although the present invention has been described with reference to particular embodiments and examples, it will be apparent to those skilled in the art that variations and modifications can be substituted therefor without departing from the principles and true spirit of the invention.

Having claimed is:

1. In the production of stable aqueous dispersions of a detergent selected from the group consisting of nonionic, anionic, cationic and amphoteric compounds in aqueous solutions of inorganic builder salts containing polymeric dispersing agent, wherein the amount of inorganic builder salt in the absence of said polymeric dispersing agent results in a salting out of the detergent, the improvement which comprises mixing in a ratio of from about 8:1 to greater than 1:1, a nonionic detergent With an ethylenically unsaturated monomer substantially unreactive with said nonionic detergent and which on polymerization yields a polymeric dispersing agent which contains a water solubilizing group, and converting said monomer in admixture with said nonionic detergent to said polymeric dispersing agent by a process including said polymerization.

2. Process as set forth in claim 1, in which after said polymerization the resulting polymer is converted to said dispersing agent by salt formation.

3. Process as set forth in claim 1 wherein the amount of said inorganic builder salt ranges from about 1 to- 5 parts per part of detergent.

4. Process as set forth in claim 1 in which said nonionic detergent is an ethoxylated compound having an aliphatic chain of at least 8 carbon atoms, said nonionic detergent being insoluble in said aqueous inorganic builder salt solution and being dispersed therein by said polymeric dispersing agent.

5. Process as set forth in claim 1 in which said monomer is an alpha-beta unsaturated carboxylic acid.

thus described the invention, what is 6. Process as set forth in claim 5 in which said dispersing agent is a Water-soluble salt of a polymer of said acid, said process including the steps, subsequent to polymerization, of converting the polymer of said acid to said polymeric salt and adding a builder salt.

7. Process as set forth in claim 1 in which said builder salt is tetrapotassium pyrophosphate.

8. Process as set forth in claim 3 wherein the inorganic builder salt concentration ranges from about 10 to 40% based on the weight of water plus builder salt.

9. Process as set forth in claim 4, said monomer comprising an alpha-beta unsaturated carboxylic acid polymerizable by addition polymerization at its olefinic double bond, said dispersing agent being a water-soluble salt of a polymer of said acid, said process including the steps, subsequent to polymerization, of converting the polymer of said acid to said polymeric salt and adding said builder salt in aqueous dissolved liquid condition, the polymerization being carried out in the presence of water in amount of less than 40% of the total weight of said monomer and said nonionic detergent, the ratio of the amount of said nonionic detergent to the amount of polymerizable monomer employed in the polymerization being in the range of about 4:1 to 1:1, said polymerization yielding a pourable mixture, said nonionic detergent being insoluble in said aqueous builder salt solution and being dispersed therein by said polymeric dispersing agent.

References Cited UNITED STATES PATENTS 3,321,408 5/1967 Briggs 252161 3,256,202 6/1966 Weiss 252138 3,235,505 2/1966 Tunell 252l35 3,294,727 2/1966 Grommers et a1. 26078.5

MAYER WEINBLATI, Primary Examiner D. L. ALBRECHT, Assistant Examiner U.S. Cl. X.R.