Cleaning compositions for solid surfaces – auxiliary compositions – Auxiliary compositions for cleaning – or processes of preparing – Textile softening or antistatic composition
Reexamination Certificate
1995-10-19
2003-05-06
Green, Anthony (Department: 1755)
Cleaning compositions for solid surfaces, auxiliary compositions
Auxiliary compositions for cleaning, or processes of preparing
Textile softening or antistatic composition
C510S276000, C510S329000, C510S330000, C510S504000, C510S521000, C510S522000, C510S527000
Reexamination Certificate
active
06559117
ABSTRACT:
TECHNICAL FIELD
The present invention relates to concentrated aqueous textile treatment compositions. In particular, it relates to textile treatment compositions for use in the rinse cycle of a textile laundering operation to provide fabric softening/static control benefits, the compositions being characterized by excellent storage stability and excellent viscosity stability after freeze/thaw cycling.
BACKGROUND OF THE INVENTION
Aqueous textile treatment compositions suitable for providing fabric softening and static control benefits during laundering are well-known in the art and have found wide-scale commercial application. Conventionally, aqueous, rinse-added, fabric softening compositions contain, as the active softening component, substantially water-insoluble cationic materials having two long alkyl chains. Typical of such materials are di-hydrogenated tallow di-methyl ammonium chloride and imidazolinium compounds substituted with two stearyl groups. These materials are normally prepared in the form of a dispersion in water. It is generally not possible to prepare such aqueous dispersions with more than about 10% cationic materials without encountering intractable problems of product viscosity and stability, especially after storage at lower temperatures, such that the compositions are unpourable and have inadequate dispensing and dissolving characteristics in rinse water. This physical restriction on softener concentration limits the level of softening performance achievable without using excessive amounts of product and also adds substantially to the costs of distribution and packaging. Accordingly, it would be highly desirable to prepare physically acceptable aqueous textile treatment compositions containing much higher levels of substantially water-insoluble cationic softener materials.
Cationic softener materials are normally supplied by the manufacturer containing about 70%-90% of active material in an organic liquid such as isopropanol or ethanol, sometimes containing a minor amount of water (up to 10%). Retail fabric softening compositions are then prepared by dispersion of the softener in warm or hot water under carefully controlled conditions. The physical form and dispersibility constraints of these industrial concentrates are such as to preclude their direct use by the domestic consumer; indeed, they can pose severe processing problems even for the industrial supplier of retail fabric softening compositions.
Many of the various solutions to the specific problem of preparing aqueous fabric softening compositions in concentrated form suitable for consumer use have not been entirely satisfactory. It is generally known (for example, in U.S. Pat. No. 3,681,241, Rudy, issued Aug. 1, 1972) that the presence of ionizable salts in softener compositions does help reduce viscosity, but this approach by itself is ineffective in preparing compositions containing more than about 12% of dispersed softener, inasmuch as the level of ionizable salts necessary to reduce viscosity to any substantial degree has a seriously detrimental effect on product viscosity stability.
SUMMARY OF THE INVENTION
It has now been discovered that the product stability and viscosity characteristics of concentrated fabric softener compositions containing mixtures of (A) biodegradable diester quaternary ammonium softening materials, (hereinafter referred to as “(A)”), and (B) specific co-active fabric softening materials, (hereinafter referred to as “(B)”), (i.e., substituted imidazoline compounds and specific quaternary ammonium salts which are not the same as (A)), are superior both at normal and lower temperatures. The value of using such mixtures of fabric softening materials for enhancing the long term viscosity characteristics and stability of concentrated aqueous cationic fabric compositions especially after freeze/thaw cycling, has hitherto not been recognized in the art.
DETAILED DESCRIPTION OF THE INVENTION
(A). Biodegradable Quaternized Ester-Amine Softening Material
The present invention contains diester quaternary ammonium material (hereinafter referred to as “DEQA”) as an essential component. The DEQA preferably comprises, as the primary active, compounds of the formula:
wherein each R substituent is a short chain C
1
-C
6
, preferably C
1
-C
3
alkyl or hydroxyalkyl group, e.g., methyl (most preferred), ethyl, propyl, hydroxyethyl, and the like, benzyl or mixtures thereof; each m is 2 or 3; each n is from 1 to about 4; each Y is —O—(O)C—, or —C(O)—O—, but not —OC(O)O—; each R
2
is a long chain C
12
-C
22
hydrocarbyl, or substituted hydrocarbyl substituent, preferably C
15
-C
19
alkyl or alkylene, most preferably C
15
-C
17
straight chain alkyl or alkylene such that the Iodine Value (hereinafter referred to as IV) of the parent fatty acid of this R
2
group is less than about 10, preferably less than about 5, most preferably less than about 2; and the counterion, X(−), can be any softener-compatible anion, preferably the anion of a strong acid, for example, chloride, bromide, methylsulfate, formate, sulfate, nitrate and the like. The anion can also, but less preferably, carry a double charge in which case X(−) represents half a group. These materials containing a divalent anion, in general, are more difficult to formulate as stable concentrated liquid compositions.
Carbonate esters, i.e., where Y═—O—C(O)O—, are unstable compounds and are not included as DEQA (A) compounds.
It will be understood that substituents R and R
2
can optionally be substituted with various groups such as alkoxyl or hydroxyl groups, and can be straight, or branched so long as the R
2
groups maintain their basically hydrophobic character. The preferred compounds can be considered to be diester variations of ditallow dimethyl ammonium chloride (hereinafter referred to as “DTDMAC”), which is a widely used fabric softener. At least 80% of the DEQA is in the diester form, and from 0% to about 20% can be DEQA monoester (e.g., only one of the ester groups is hydrolyzed to yield either —Y—H, or an —OH group).
As used herein, when the diester is specified, it can include the monoester that is present. For softening, under no/low detergent carry-over laundry conditions the percentage of monoester should be as low as possible, preferably no more than about 2.5%. However, under high, anionic detergent surfactant or detergent builder carry-over conditions, some monoester can be preferred. The overall ratios of diester to monoester are from about 100:1 to about 2:1, preferably from about 50:1 to about 5:1, more preferably from about 13:1 to about 8:1. Under high detergent carry-over conditions, the di/monoester ratio is preferably about 11:1. The level of monoester present can be controlled in manufacturing the DEQA.
The above compounds, used as the biodegradable quaternized ester-amine softening material in the practice of this invention, can be prepared using standard reaction chemistry. In one synthesis of a di-ester variation of DTDMAC, an amine of the formula RN(CH
2
CH
2
OH)
2
is esterified at both hydroxyl groups with an acid chloride of the formula R
2
C(O)Cl, then quaternized with an alkyl halide, RX to yield the desired reaction product (wherein R and R
2
are as defined hereinbefore). However, it will be appreciated by those skilled in the chemical arts that this reaction sequence allows a broad selection of agents to be prepared. The following are non-limiting examples (wherein all long-chain alkyl substituents are straight-chain):
where —C(O)R
2
is derived from hardened tallow fatty acid.
Since the foregoing materials (diesters) are somewhat labile to hydrolysis, they should be handled rather carefully when used to formulate the fabric softening composition herein. For example, stable liquid compositions herein are formulated at a neat pH in the range of from about 2 to about 5, preferably from about 2 to about 4.5, more preferably from about 2.5 to about 4. The pH can be adjusted by the addition of a Bronsted acid. pH ranges for making stable softener compositions containing diester qu
Mermelstein Robert
Severns John Cort
Vogel Alice Marie
Wahl Errol Hoffman
Green Anthony
William Zerby Kim
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