Oxygen Bleach-activator Systems Stabilized With Puffed Borax

Abstract

Oxygen releasing bleaches such as perborates are combined with activators and puffed borax to provide compositions unusually stable upon storage under adverse conditions of high temperature and humidity to which they are normally subjected.

Description

The invention relates generally to bleach compositions comprising an oxygen-releasing bleach, an activator for the oxygen-releasing bleach and a stabilizer to prevent premature release of the oxygen and breakdown of the bleach composition. More specifically this invention concerns compositions of perborate bleaches, an activator for the perborate bleaches, puffed borax as a stabilizer and an optional non-ionic surfactant. The bleach-stabilizer-activator system may additionally contain additive ingredients common to bleach systems, such as those included in a heavy duty laundry detergent composition.

BACKGROUND OF THE INVENTION

The use of bleaching agents as aids to laundering is well known. Of the two major types of bleaches, oxygen-releasing and chlorine-releasing, the oxygen bleaches are more advantageous to use in that oxygen bleaches do not attack the fluorescent dyes commonly used as fabric brighteners or the fabrics and do not, to any appreciable extent, yellow the resin fabric finishes as chlorine bleaches are apt to do. However, one major drawback to an oxygen bleach is the high temperatures (140.degree.-160.degree. F.) necessary to efficiently activate the bleach. The United States washing temperatures are in the range of 120.degree.-130.degree. F., below the effective temperatures for activating an oxygen bleach. Considerable effort has been expended to find substances to activate the oxygen bleach at lower temperature.

The use of various substances as oxygen bleaches are taught. These include hydrogen peroxide and per compounds which give rise to hydrogen peroxide in aqueous solution. Suitable compounds include water soluble oxygen releasing compounds such as the alkali metal persulfates, percarbonates, perborates, perpyrophosphates and persilicates. Although not all of the preceding are true persalts in the chemical sense they are believed to provide hydrogen peroxide in aqueous solution. Among the suggested oxygen bleach activators are heavy metal salts of transition metals as cobalt, iron or copper combined with chelating agents as picolinic acid (U.S. Pat. No. 3,156,654) or stronger chelating agents at higher temperatures as methylaminodiacetic acid, aminotriacetic acid and hydroxyethylaminodiacetic acid (U.S. Pat. No. 3,211,658). Esters have been suggested as activators for oxygen releasing bleach. Exemplary are chloroacetyl phenol and chloroacetyl salicylic acid (U.S. Pat. No. 3,130,165), triacetyl cyanurate, N,N,N.sup.1, N.sup.1 -tetraacetylethylene diamine and sodium-p-acetoxy benzene sulfonate. Recently, benzoylimidazole and its derivatives with some success have been used. The problems inherent in activating oxygen bleach systems is discussed fully in, Effective Bleaching With Sodium Perborate, Dr. A.H. Gilbert, Detergent Age, June 1967 pages 18-20, July 1967 pages 30, 32, 33 and August 1967 pages 26, 27, and 67.

One major drawback which has prevented the widespread use and acceptance of the previously described oxygen bleach-activator systems is that the activators tend to react with the oxygen bleach in the package. This results in limited effectiveness of the bleach composition, a poor commercial product and lack of consumer acceptance. A prime requirement of a commercial bleach product is that it give standardized results, i.e., similar results from similar amounts of bleach at different times. The known activated perborate (oxygen) bleach compositions have failed to give such satisfactory standardized results. The premature activation in the package of the perborate bleach by the activator especially under the adversely high humidity conditions present in laundry areas results in products that continuously lose their original bleaching potential during product storage and use. This results in products which do not provide uniform results to the consumer.

OBJECT OF THE INVENTION

In the light of the noted disadvantages in using oxygen (perborate) bleaches, it is an object of this invention to provide an oxygen bleach-activator system which has been stabilized against deterioration in the presence of moisture.

In general, according to this invention, the stabilization of the oxygen bleach-activator system is accomplished by using a specific filler, namely, puffed borax, in the bleach compositions. The puffed borax used in this invention is a known form of borax made by the rapid heating of hydrates of sodium tetraborate. The compound is characterized by versatility of bulk density, large surface area, rapid solubility rate, and high absorptive potential for many substances. The puffed borax contemplated for inclusion in compositions of the invention, is further characterized by having less than 5 moles of water per mole of sodium tetraborate, a bulk density ranging from about 3 lbs./cu. ft. to about 40 lbs./cu. ft. and a particle size distribution based on the desired bulk density and the proper selection of the starting borax feed material. Found to be particularly useful are puffed boraxes having particle size distribution so that the major proportion of the puffed borax is of a size within the U.S. sieve range of from -20 to about +200. In the more preferred forms over 90 percent of the particles of puffed borax are in the U.S. sieve range from about 40 to 60. At the optimum compositions of the instant disclosed inventions, the bulk density of the puffed borax is about 15 lbs./cu. ft.

We have discovered that puffed borax has a surprising and unexpected stabilizing effect on oxygen bleach-activator systems, even when the systems are exposed to extremes of temperature and humidity.

The oxygen bleach-activator compositions of the present invention may also include conventional additives for such compositions. These may include binders, other fillers, builders, optical brighteners, perfumes, colorings, enzymes, bacteriostats, etc., all of which may be added to provide properties required in any particular instance. Additionally, the stabilized oxygen bleach-activator compositions can be incorporated into cleaning compositions containing soap and/or synthetic organic detergents and formulated for use as heavy duty household detergents, fine fabric washing detergent systems or clothes washing formulations in general.

Illustrative of the soaps which may be used in the present invention are the well known salts of fatty acids. These may include the Na, K, Li or ammonium salts of nyristic, palmitic, stearic, behenic, oleic, lauric, abietic, capric, caproic, ricinoleic, linoleic, hydrogenated and dehydrogenated abietic acids, the surface active hydrolysis products of tallow, coconut oil, cottonseed oil, soybean oil, peanut oil, sesame oil, linseed oil, olive oil, corn oil, castor oil, and the like.

Illustrative of the synthetic organic detergents useful in the present invention, there may be mentioned long chain alkyl aryl sulfonates such as sodium octyl-, nonyl-, dodecyl-, decyl-, tri-decyl and tetradecylbenzene sulfonates, N-long chain acyl N-alkyl taurates such as sodium oleoyl methyltaurate, sodium palmitoyl methyl taurate, sodium or potassium lauroyl methyl taurate and the corresponding acyl ethyl taurates, long chain alkyl oxyethlene sulfates such as sodium or potassium laurylpolyoxyethylene sulfate, sodium laurylmonooxyethylene sulfate, sodium octadecylpolyoxyethylene sulfate and sodium cetyl polyoxyethylene sulfate, long chain alkyl aryl oxyethylene sulfates such as ammonium, sodium or potassium nonyl-, octyl-, and tridecylphenol mono- and polyoxyethylene sulfates, long chain alkyl sulfates such as sodium lauryl- and stearylsulfates, long chain alkyl isethionates such as sodium oleic isethionate, sodium lauric isethionate, sodium diisopropyl naphthalene sulfonate, sodium isopropyl naphthalene sulfonate, sodium isobutyl- and diisobutyl naphthalene sulfonate, sodium isohexylbenzene sulfonate, monobutyl biphenyl sodium monosulfonate, monobutylphenylphenol sodium monosulfonate, dibutylphenylphenol sodium disulfonate, lower alkyl sulfates and sulfonates such as sodium sulfate derivative of 2-ethyl hexanol-1, sodium 2-ethyl-1-hexenyl sulfonate, sodium isooctyl sulfonate, sodium isononyl (also triisopropylene) sulfonate, lower alkyl esters of aliphatic sulfocarboxylic acids such as sodium diamyl sulfosuccinate, sodium diisobutyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium triamyl sulfotricarballylate, sodium triisobutyl sulfotricarballylate, and sodium tri-n-butyl sulfotricarballylate.

While the foregoing sodium salts of the above detergents may be preferred, other alkali metal and amine salts may be employed, as, for example, those with potassium, ammonium, lower alkyl amines such as methylamine, ethylamine, propylamine and isopropylamine, lower alkylolamines such as mono, di-, and triethanol- and isopropanolamines, cyclic amines such as cyclohexylamine, morpholine, and pyrrolidine and the like.

The above-mentioned detergents may be used alone or may be employed as mixtures. Additionally, the detergents can be used in combination with the water-soluble soaps and water conditioners. The term "water conditioner" as used in the present specification and claims designates those compounds which sequester, or inactive water hardness and aid in cleaning, and the term is fully intended to include both the inorganic and organic complexing agents, sequestering agents and chelating agents.

Referring first to the organic type of chelating and sequestering agents, the ethylene diamine tetraacetic acid type and its salts and nitrilotriacetic acid and its salts are among the most effective. While these foregoing materials are referred, there are numerous other types of organic products offered and reference may be had to the book "Chemistry of the Metal Chelating Compounds," by Martell and Calvin, for many further examples. Illustrative of the inorganic water conditioners useful in the present invention are the zeolites (hydrated silicates of aluminum and either sodium or calcium or both), sodium carbonate, sodium phosphate, sodium acid phosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, trisodium phosphate, sodium metaphosphate, sodium hexametaphosphate and sodium tetraphosphate. While the sodium salts of the inorganic compounds are preferred, the other alkali metal salts such as the potassium and lithium salts may be used.

Suitable additives, e.g., binders, additional fillers, builders, optical brighteners, perfumes, colorings, bacteriostats, etc., may be added to provide properties regarded as desirable in particular instance, as noted hereinbefore. Illustrative of some of the various additives used by those skilled in the detergent and soap art are builders (borax, sodium sulfate, sodium carbonate, etc.) corrosion inhibitors (sodium silicate), anti-redeposition agents (carboxymethyl cellulose), fabric brighteners fluorescent or optical pigments, fillers (talc), binders (gums, starches, dextrins), coloring, foam stabilizers and suppressors, preservatives and bacteriostats and bactericides (trichlorocarbanilide, trichlorosalicylanilide, tribromosalicylanilide). Each ingredient is selected to perform a specific function. The corrosion inhibitor protects the metals used in washing machines. The anti-redeposition agent is used to aid in preventing removed soil from redepositing on the fabric being washed. The foam stabilizer or suppressor aids in tailoring the sudsing characteristics of the product. The optical brighteners aid in maintaining fabric whiteness or brightness.

The compositions contemplated within this invention may be prepared in any forms recognized in the art. This would include granules, powders, beads, tablets, individual premeasured units (envelopes, packets, etc.) or combinations with coatings of various materials selected to provide a differential release rate of the ingredients forming the compositions.

The following examples are illustrative of the present invention.

EXAMPLE I

Samples were made by mixing the activating system, BID (Benzoylimidazole) with a number of fillers referred to hereinafter, and then combining the above mixture with sodium perborate monohydrate. The samples were than stored at 90.degree. F./90% R.H. in open containers for 72 hours. The samples were removed and titrated for the amount of active oxygen present with the standard permanganate titration. On Table 1, following column I specifies the filler tested. Columns II to IV, respectively, set out the amounts of filler, BID and sodium perborate in the compositions tested. Column V lists the measured O.sub.2 loss under the adverse storage conditions. ##SPC1##

Table 1 clearly delineates the unexpected stability of oxygen bleach-activator systems containing puffed borax and those containing standard fillers including light density fillers or soaps.

EXAMPLE II

A sodium perborate bleach composition was formulated into activated bleach compositions containing picolinic acid (2-pyridinecarboxylic acid) and cobalt sulfate heptahydrate (CoSO.sub.4 .sup.. 7H.sub.2 O). The sodium perborate bleach composition (control) was compared to the activated bleach compositions, with and without puffed borax, after storage under adverse conditions by measuring the amount of active oxygen lost. The compositions were prepared as follows:

a. 5 g. picolinic acid was dissolved in 100 g. ethanol to give (I);

b. 50 g. (I) was combined with 50 g. puffed borax (6 lbs./cu. ft.) to give (II);

c. 50 g. (II) was combined with 150 g. of a sodium perborate bleach composition to give (III);

d. 100 g. (III) was combined with 1 g. cobalt sulfate heptahydrate to give (IV);

e. 100 g. sodium perborate bleach composition was combined with 0.6 g. picolinic acid and 1.0 g. cobalt sulfate heptahydrate to give (V).

The samples were stored in closed glass containers at 90.degree.F./90% R.H. for 42 days. During storage the active oxygen content of the samples were measured using a standard permanganate titration.

TABLE

2 % Active Oxygen loss from Sample Composition 7- 42 days at 90.degree.F./90% R.H. __________________________________________________________________________ Control Sodium perborate None composition* IV Sodium perborate None composition* and CoSO.sub.4.sup.. 7H.sub.2 O (Puffed Borax and Picolinic Acid) V Sodium perborate 49% composition* and Picolinic Acid and CoSO.sub.4.sup.. 7H.sub.2 O __________________________________________________________________________ *Sodium perborate composition is a commercial type perborate bleaching composition containing about 4.3% available oxygen from 30% sodium perborate monohydrate, sodium tripolyphosphate, sodium silicate, sodium sulfate, non-ionic surfactant and additives such as perfumes, brighteners, etc.

The data presented in Table 2 clearly demonstrates that under the adverse test conditions the control composition showed no loss of active oxygen. The complete activated oxygen bleach activator system containing picolinic acid and cobalt sulfate showed a 49 percent loss under the measured adverse storage conditions; whereas, the same composition protected with puffed borax showed no loss.

EXAMPLE III

A perborate activating system was prepared in the following manner: One gram of benzoylimidazole (BID) was solubilized in a non-ionic surfactant or glycol which was liquid at ambient room temperature. Then 0.50 g. of the non-ionic-BID mixture was mixed with 2.00 g. of puffed borax (15 lbs./cu. ft. density). This puffed borax activator system was admixed with sodium perborate monohydrate (15.2 percent active oxygen) giving a BID:Na Perborate monohydrate ratio of 0.25:0.23. The sample was then stored in open containers at 90.degree. F./75% R.H. for 72 hours, after which time active oxygen content was determined by the standard permanganate titration.

The non-ionic surfactants used will preferably (although not necessarily) be liquid at ambient use temperature. The non-ionic surfactant glycol may be chosen from the following general classes:

1. Straight chain alkylphenoxypoly (ethyleneoxy) ethanols having the general formula:

wherein R is an alkyl radical and n is the number of moles of ethanol oxide in the molecule (Igepals, GAF).

2. Ethoxylates of isomeric linear secondary alcohols having the general formula:

wherein n is the number of moles of methylene and x is the number of moles of ethylene oxide in the molecule. (Tergitols, Union Carbide).

3. Condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol having the general formula:

wherein a and c represent moles of ethylene oxide and b represent moles of propylene glycol. (Pluronics, Wyandotte Chemical).

4. Addition products of propylene oxide to ethylene diamine followed by the addition of ethylene oxide having the general formula:

wherein x and y represent respectively the number of moles of propylene oxide and ethylene oxide in the molecule. (Tetronics, Wyandotte Chemicals).

5. Ethylene oxide adducts of straight chain alcohols having the general formula:

CH.sub.3 --(CH.sub.2).sub.x --CH.sub.2 --(O--CH.sub.2 --CH.sub.2).sub.y --OH

wherein x is the number of methyl groups (chiefly C.sub.12 to C.sub.18) and y is the number of moles of ethylene oxide present. (Alfonics, Conoco).

6. Glycols such as propylene glycol, triethylene glycol and trimethylene glycol.

For comparison purposes a cationic surfactant mixture was also used. A mixture of n-alkyl-di(lower)alkylbenzyl-ammonium chlorides and n-alkyl-di(lower)alkyl(lower)alkylbenzyl-ammonium chlorides was incorporated in sample compositions.

Each sample of table 3 contains 0.25 gm. of BID and 0.23 gm. of Na Perborate.sup.. H.sub.2 O.

TABLE 3

A B C D E Gm. Gm. Gm. % Active Sample Sur- Sur- Puffed Borax Oxygen loss __________________________________________________________________________ factant factant 1 None -- None 44 2 None -- 2.00 23 3 Pluronic.sup.a 0.25 2.00 20 L-61 4 Alfonic.sup.b 0.25 2.00 15 10-12-6 5 Triethylene 0.25 2.00 10 Glycol 6 Tetronic.sup.c 0.25 2.00 11 701 7 Tergitol.sup.d 0.25 2.00 22 15-S-9 8 BTC.sup.e 0.25 2.00 32 2125 __________________________________________________________________________ (a) Pluronic L-61--having a molecular weight of the poloxypropylene hydrophobic base of about 1750 and about 10% polyoxyethylene in the total molecule and an average molecular weight of about 2000. (b) Alfonic 10-12-6--having an average ethylene oxide content of about 60% and an alkyl chain of C.sub.10 to C.sub.12. (c) Tetronic 701--having a molecular weight of about 3600. (d) Tergitol 15-S-9--having C.sub.11 -C.sub.15 linear alcohol and 9 moles of ethylene oxide per molecule. (e) BTC 2125--(50% active) (U.S. Pat. No. 2,676,986) 25% n-alkyl (60% C.sub.14, 30% C.sub.16, 5% C.sub.12, 5% C.sub.18) dimethyl benzyl ammonium chlorides, 25% n-alkyl (50% C.sub.12, 30% C.sub.14, 17% C.sub.16, 3% C.sub.18) dimethyl ethylbenzyl ammonium chlorides. 50% inert ingredients.

It is apparent from the above data that: (1) the use of puffed borax as a filler increases the active oxygen life of Na Perborate, (2) the use of non-ionic surfactants tends to increase the active oxygen life of Na Perborate while cationics have an opposite effect (Sample No. 8) and (3), the various non-ionics give varying results.

EXAMPLE IV

The effect of puffed borax on various sodium perborate compositions was tested. The results expressed as percent tea stain removal was measured by a Tergotometer after washing at 120.degree. F. for 20 minutes. The data in Tables 4 and 5 clearly demonstrates that the effect of oxygen bleach activator is unhindered by the presence of puffed borax. The compositions are expressed as percent by weight.

TABLE 4

With heavy duty detergent composition

Sample A B C D __________________________________________________________________________ % BID 5.85 3.30 1.69 0.00 % Na Perborate 5.15 2.80 1.45 2.92 (15-16% Active O.sub.2) % Puffed Borax 44.50 46.95 48.43 48.54 % Detergent 44.50 46.95 48.43 48.54 Composition* % Tea Stain 80 75 65 47 Removal __________________________________________________________________________

TABLE 5

Without heavy duty detergent composition

Sample A B C D __________________________________________________________________________ % BID 17.44 10.44 6.19 0.00 % Na Perborate 15.44 9.23 5.31 10.31 (15-16% Active O.sub.2) % Puffed Borax 67.12 80.33 88.50 89.69 % Tea Stain 65.00 40.00 16.00 0.60 Removal __________________________________________________________________________ *A commercially available heavy duty detergent composition comprising about 20% alkyaryl sulfonate, 45-50% sodium tripolyphosphate and q.s. to 100% of additives.

The formulations of the present invention may be produced by various conventional mixing operations. These would include dry blending, spray drying and wet (slurry) blending methods. It has been found that the best stability characteristics of perborate bleaches are produced when the activator is mixed with a non-ionic (preferably liquid at ambient room temperature) and this mixture incorporated with puffed borax. If desired, small amounts (up to 5 percent by weight) of an alcohol such as methanol, ethanol or isopropanol may be included to act as a thinning agent in preparing the compositions of the present invention.

In general, the compositions of the present invention may comprise, by weight:

Puffed Borax from about 0.1 percent up to about 99.0 percent. Oxygen bleach activator from about 0.1 percent up to about 25.0 percent.

Non-ionic surfactant up to about 25.0 percent.

Oxygen releasing bleach substance from about 0.1 percent up to about 40.0 percent.

Builders and fillers up to about 99.0 percent.

Bleach composition adjuvants (brighteners, perfumes, detergents, etc.) up to about 99 percent.

In the more preferred form, the compositions of the active ingredients of the present invention may comprise, by weight:

Puffed Borax from about 40.0 percent up to about 95.50 percent. Oxygen bleach activator from about 1.50 percent up to about 20.0 percent.

Oxygen releasing bleach substance from about 1.00 percent up to about 30.0 percent.

Particular compositions which utilize the principles taught by the present invention are, by weight:

I. Spray Dried Build Oxygen Releasing Bleach Active Oxygen 2.25% Puffed Borax 47.75% BID 2.25% Sodium Perborate Composition.sup. (a) 50.00%

II. Dry Blended Oxygen Releasing Bleach Active Oxygen 0.75% Puffed Borax (6 to 30 lbs./cu. ft.) 50.0% BID 6.0% Pluronic L-61 6.0% Na Perborate .sup.. H.sub.2 O (15-16% active oxygen) 5.0% Sodium Tripolyphosphate 32.0% Adjuvants--dye, optical brightener, perfume, etc., q.s. 100.0%

Claims

What is claimed is:

1. A stabilized oxygen-active bleaching composition consisting essentially of about 1 to about 30 percent by weight of an inorganic peroxy compound which is an oxygen releasing bleaching substance, about 1.5 to about 20 percent by weight of an activator for said oxygen releasing bleaching substance, selected from the class consisting of benzoylimidazole, a chelating agent-transition metal salt composition, chloroacetyl phenol, chloroacetyl salicyclic acid, triacetyl cyanurate, N, N, N.sup.1, N.sup.1 -tetraacetylethylene diamine and sodium-p-acetoxy benzene sulfonate, about 40 to about 95.5 percent by weight of a puffed borax which is characterized by having a bulk density in the range from about 3 lbs./cu. ft. to about 40 lbs./cu. ft., a particle size in the U. S. sieve range of from about -20 to about +200 and having less than about 5 moles of water per mole of sodium tetroborate, and about 5 to about 25 percent by weight of an additive selected from the class consisting of a non-ionic surfactant and a glycol, said glycol being selected from the class consisting of propylene glycol, trimethylene glycol and triethylene glycol.

2. The composition of claim 1 wherein said peroxy compound is sodium perborate.

3. The composition of claim 1 wherein said activator for the oxygen-active bleach substance is benzoylimidazole.

4. The composition of claim 1 wherein said activator for the oxygen-active bleach substance is composed of a chelating agent and a transition metal salt.

5. The composition of claim 4 wherein said chelating agent is picolinic acid and said transition metal salt is cobalt sulfate.

6. The composition of claim 1 wherein said puffed borax has a bulk density of about 15 lbs./cu. ft. and wherein the major portion of the particle size in the U.S. sieve range is from about +40 to about +60.

7. The composition according to claim 1 wherein said additive is a glycol which is triethylene glycol and is present in an amount between about 5 and about 10 percent by weight of said composition.

8. The composition according to claim 1 wherein said oxygen-releasing bleaching substance is a perborate.

9. A stabilized oxygen-active bleaching composition consisting essentially of about 50.00 percent by weight of a puffed borax, about 6.0 percent by weight of a benzoylimidazole, about 5.0 percent by weight of sodium perborate, about 32.0 percent by weight of sodium tripolyphosphate, about 6.0 percent by weight of a compound of the formula

having a molecular weight of about 2,000 and a and c are selected such that the compound has about 10.0 percent of polyoxyethylene by weight, said puffed borax being characterized by a bulk density of about 15 lbs./cu. ft. and a particle size in the U.S. seive range from about -20 up to about +200 with the major portion in the U.S. sieve range of from about +40 to about +60.