US 3501335 A
Description (OCR text may contain errors)
United States Patent O Int. Cl. Bc 9/08 US. Cl. 117-66 Claims ABSTRACT OF THE DISCLOSURE A novel process of fabric conditioning is disclosed employing N-2-hydroxyalkylamine oxides, and ethylene oxide adducts thereof as the fabric conditioning agents. The use of the ethylene oxide adducts of the N-2- hydroxyalkylamine oxides has been found especially advantageous because these compounds possess self-emulsifying properties.
This invention relates to the conditioning of fabrics and more particularly to novel fabric softeners and to a method of treating fabrics to impart a desirable softness thereto.
It has been well-known for a number of years in the manufacture of fabrics to provide for one or more finishing steps whose function is to impart a desirable softness or feel to the finished fabric. With the advent of chemical fabric softeners in the l930s, the use of a variety of chemical agents for this purpose has become increasingly widespread.
In more recent years the use of fabric softeners in home laundries has also become popular. This has been brought about largely by the widespread use of synthetic detergents containing significant amounts of alkaline phosphates for home laundry purposes. It is known that certain of the alkaline phosphates will combine with the calcium and magnesium salts characteristic of hard water to leave deposits in the washed fabric which tend to impart a harshness or stiffness to the fabric. The use of fabric softeners in the final rinse, analogous to the commercial finishing of fabrics, has become widely used in home laundries for overcoming this characteristic harshness.
The present invention is directed to certain novel compounds having unexpected fabric softening ability. More specifically, the present invention is concerned with amine oxides of the general formula:
R is an alkyl radical having from 14 to 18 carbon atoms;
R and R are selected from the group consisting of alkyl and hydroxyalkyl containing from 1 to 3 carbon atoms;
R is an alkyl group containing from 14 to 22 carbon atoms; and
n is a small whole number from x being the number of carbon atoms in R in excess of 12.
By treating fabrics with the foregoing amine oxides,
they are rendered soft to the touch and are more easily ironed after laundering.
Treatment may be carried out by employing any of the methods known in the art for the purpose of softening fabrics. In general terms, these methods are adapted to bring about the formation of at least a more or less monomolecular layer on the fabric to be softened. One of the most effective and Widely used methods is to prepare an aqueous dispersion of the fabric softening agent in the order of about 0.01% (by weight), and immersing the fabric to be softened in such a dispersion. When employing fabric softeners having appropriate substantivity, the softening agent dispersed in the water will be exhausted onto the fabric immersed therein. Other methods of application are known, however. One method which has been proposed as a household convenience is to package the softening agent in an aerosol dispensing can, whereby the agent may be sprayed as a mist and applied directly to the article to be softened. This latter method, obviously, is likely to result in a film of significantly more than monomolecular thickness. The excess amount of fabric softener, however, is in no way deleterious to the softening action of the agent employed.
The ability of various compounds to soften fabrics is quite unpredictable. Many of the commercial fabric softeners are Well-known to be characterized by the presence of one or more 16-20 carbon atom fatty groups. If the fatty groups of the compound have substantially fewer than 16 carbon atoms (i.e., C groups), the fabric softening ability appears to be lost. On the other hand, compounds in which the fatty groups have substantially more than 20 carbon atoms, i.e., C tend to impart an undesirable water repellency to the fabric.
Nevertheless, the mere presence in the compound of fatty radicals which predominantly contain 16 to 20 carbon atoms provides no assurance that the compound will have fabric softening ability.
The chain length of the fatty radicals in the fabric softening compound is believed to be closely related to the hydrophilic-hydrophobic balance of these compounds in qualitative terms, it is known that the successful fabric Softeners must have a marginal solubility, that is, they are compounds which will dissolve in water but the resulting solution is colloidal in nature, rather than being a true solution. Materials which are too soluble will not be readily retained by the fabric, or, even if retained, will be lost through subsequent handling and/or washing. On the other hand, materials which are of too low a solubility are usually ineffective for the reason that they cannot be dispersed in water in a concentration sufficiently high to provide useful results.
It will be apparent to those skilled in the art, that there is some latitude in controlling the hydrophilic-hydrophobic balance of various classes of surface-active agents. Thus, for instance, in the amine oxides with which the present invention is concerned, if the low molecular weight groups attached to the oxidized nitrogen (i.e., CH C H C H OH, etc.) do not provide a high degree of solubility, then the amine oxides having lower molecular weight i.e., C or C can be used successfully. On the other hand, if the amine oxide is ethoxylated to to increase its solubility, the longer chain fatty groups may be present, i.e., C or C and the shorter chain, fatty groups, such as the C groups, may be of reduced effectiveness as fabric softeners.
While the marginal solubility property just described is an important attribute of fabric softeners, other characteristics are also desirable. Substantivity is particularly important. This is desired not only for the purpose of obtaining effective deposition of the fabric softener onto the fabric to be softened, but also to prevent subsequent loss of the fabric softener through handling and/ or Washing. In the case of the well-known quaternary ammonium compounds, substantivity to cotton (which is particularly important) is commonly attributed to an electrostatic attraction between the negatively charged cotton molecules and the positively charged quaternary ammonium ion. Other fabric softeners having substantivity are known, which, however, do not have the characteristic positive charge of the quaternary ammonium ion. As to these, the theoretical basis of substantivity is not clear.
The compound with which the present invention is concerned falls into the latter class. It is known that the amine oxides are essentially nonionic in character in neutral or alkaline medium. It should be noted that the nonionic character of the amine oxides is particularly desirable since the fabric softeners based thereon will be compatible with ionic substances which may be present such as detergents and builders.
Still another important property is the ability of the fabric softener to be easily dispersed in preparing formulations for household use. In this respect the ethoxylated derivatives of the amine oxides are especially suitable. It has been found that the ethoxylated compounds have the surprising and unexpected property of being self-emulsifying. Hence, when incorporated into an aqueous dispersion, the presence of special emulsifiers or emulsion stabilizerS is not needed.
Having in mind the foregoing general characteristics of the compounds within the scope of the present invention, a number of suitable examples of fabric softeners may be mentioned. These include:
be prepared by reacting a 1,2-epoxyalkane with a secondary amine according to the following equation:
the resulting 2-hydroxy-alkylamine may be oxidized by techniques known in the art. Suitable procedures using hydrogen peroxide or other oxidizing agents are disclosed in United States Patent No. 2,169,976 and No. 2,769,824. The preparation of these compounds is illustrated by the following example.
EXAMPLE I (a) Preparation of 2-hydroxyalkylamines Into a 500 ml. Erlenmeyer flask was placed a mixture composed of 0.3 mole of a 1,2-epoxyalkane, 0.3 mole (31.5 grams) of diethanolamine and 50 ml. of 95% ethyl alcohol (in the case of 1,2-epoxyoctadecane, 100 ml. of alcohol were required). The mixture was heated with occasional stirring until a homogeneous solution was obtained. The alcohol was then distilled off, final traces of alcohol being removed by heating the residue at reduced pressure.
The product N,N-(di 2 hydroxyethy1)-2-hydroxyalkylamine, was cooled to room temperature where it solidified. A sample of the crude product was recrystallized in ethyl acetate, and the recrystallized material was used for analysis and melting point determination. N,N- (di 2 hydroxyethyl) 2 hydroxyhexadecylamine and N,N (di-Z-hydroxyethyl) 2 hydroxyoctadecylamine were prepared.
The foregoing was repeated substituting methylethanolamine and di-2-hydroxypropylamine for the di-2-hydroxyethylamine mentioned above, except that the recrystallization step was omitted. Products thus prepared were:
N-methyl-N-(Z-hydroxyethyl) -2-hydroxyhexadecylamine N,N- 2-hydroxypropyl) -2-hydroxyhexadecylamine (b) Preparation of Z-hydroxyalkylamine-N-oxides To an alcoholic solution of a 2-hydroxyalkylamine prepared from 0.04 mole of the amine and 100 ml. of ethyl alcohol were added 24 ml. of 30% hydrogen peroxide. The solution was maintained at 4050 C. for 24 hours. Excess hydrogen peroxide was then decomposed by placing a 1" by 2" piece of platinum foil into the solution, and allowing it to remain for an additional three to four days. When gas bubbles no longer formed on the surface of the platinum, it was removed and the solvent was evaporated by passing a stream of air over the surface of the solution. The residual paste Was placed in a resin kettle and dried over phosphorus pentoxide at 0.5 mm. absolute pressure of mercury.
The dried residue was recrystallized from ethyl acetate. The product, as isolated, contained free hydrogen peroxide, detected by a potassium iodide-starch test. To decompose this residual hydrogen peroxide, the crystalline amine oxide was dissolved in ethyl acetate at 50 C. and 0.1 to 0.5 g. of solid lead acetate was added thereto. When gas evolution had subsided the suspension was filtered. The compounds thus prepared were:
N,N- (di-2-hydroxyethyl -2-hydroxyhexadecylamine oxide;
N,N- (di-Z-hydroxyethyl) -2-hydroxyoctadecylamine oxide;
N-methyl-N- 2-hydroxyethyl) 2-hydroxyhexadecylamine oxide; and
N,N- di-Z-hydroxypropyl -2-hydroxyhexadecylamine oxide. In an analogous manner other compounds may be prepared, for example:
N-methyl-N-( 2-hydroxyethyl -2-hydroxyoctadecylamine oxide;
Each of the foregoing compounds may be converted into the corresponding ethoxylated compound by reacting ethylene oxide with an amine oxide following methods known in the art.
Various compounds prepared in accordance with Example I Were tested for fabric softening ability, A simple test for this purpose was devised as outlined in EX- ample II.
EXAMPLE II Three pieces of Startex cloth and three pieces of terry cloth, all four inches square, were washed in a Terg-O Tometer in 1,000 ml. of a solution of a commercial detergent at a concentration equivalent to 3.5 ounces per 16 gallons of water. The agitator was operated for 20 minutes, and the detergent solution waes at a temperature of 125 C.
After the 20 minute washing period, the cloths were rinsed for 5 minutes in 1,000 ml. of water at F. Thereafter, the cloths were treated with a second rinse solution containing a fabric softener, by agitating 1,000 ml. of a dispersion of the fabric conditioner at a concentration equivalent to 1.3 ounces per 16 gallons. The Terg-O-Tometer was used for this step also, The temperature of treatment was 100 F.
After the second rinse step, the cloths were dried and subjectively evaluated for softness by a panel of laboratory personnel.
Using the foregoing procedure, a variety of fabric softeners prepared in accordance with the present invention were tested.
As may be seen from the foregoing; the compounds of the present invention are of particular value as the active agents in fabric softening formulations. Typical fabric softening formulations within the contemplation of the present invention include, but are not limited to, the following:
EXAMPLE III Percent N,N-(di-2-hydroxyethyl) 2 hydroxytetradecyl- 6 N,N-(di-2-hydroxyethyl) 2 hydroxyocetadecyl- 2 Emulsion stabilizer. 3 Emulsifier.
EXAMPLE IV The ethoxylated amine oxide mentioned in the foregoing examples can be prepared by a procedure analogous to that described in Example I. The following preparation of the hexa-ethoxylated N(Z-hydroxyhexadecyl) diethanolamine-N-oxide is illustrative.
1,2 epoxy hexadecane was reacted with diethanol amine in accordance with the procedure of Example I, and the reaction product was recovered. Thereafter the N(2-hydroxyhexadecyl) diethanol amine thus prepared was ethoxylated using a standard ethoxylation procedure. A mixture of the amine and a catalytic amount of sodium methoxide was heated to to C. and ethylene oxide was passed through the system. The ethylene oxide was added until the weight increase of the system corresponded to the gain calculated for the addition of 6 moles of ethylene oxide for each mole of amine. The catalyst was then neutralized and the reaction product was separated.
The oxidation of the ethoxylated N(Z-hydroxyhexadecyl) diethanol amine was carried out as illustrated in Example I for the oxidation of the non-ethoxylated analogues. In a 150 ml. beaker, 10 gm. of the ethoxylated amine were dissolved in 50 ml. of isopropanol. 5 ml. of 30% hydrogen peroxide were added and the resultant solution was heated to 40 to 50 C. for 12 hours. Thereafter the unreacted peroxide was decomposed with platinum foil, and the product was recovered. The product had the formula:
1. In a method of cleansing and softening cloth articles comprising the steps of washing the cloth article to be softened and thereafter rinsing the washed cloth article in rinse water, the improvement wherein there is present in said rinse water an effective amount of a fabric softening compound selected from the group consisting of amine oxides of the formula and adducts of amine oxides of the formula with n moles of ethylene oxide, wherein R is an alkyl radical having from 14 to 18 carbon atoms;
R and R are selected from the group consisting of alkyl and hydroxyalkyl containing from 1 to 4 carbon atoms;
R; is an alkyl group containing from 14 to 22 carbon atoms; and
n is a small whole number from x being the number of carbon atoms in R in excess of 12;
said rinsing being carried out under conditions which cause exhaustion of said fabric softening compound on to said fabric. a
2. A method according to claim 1 wherein the compound is N,N-(di-2-hydroxyethyl)-2-hydroxytetradecylamine oxide.
3. A method according to claim 1 wherein the compound is, N,N-(di-Z-hydroxyethyl)-2-hydroxyhexadecylamine oxide.
4. A method according to claim 1 wherein the compound is N,N- (di-2-hydroxyethyl)-2-hydroxyoctadecylamine oxide.
5. A method according to claim 1 wherein the compound is N -methyl-N-(2-hydroxyethy1)-2-hydroxyhexadecylamine oxide. 4
6. A method according to claim 1 wherein the compound is N-methyl-N-(2-hydroxyethyl)-2-hydroxyoctadecylamine oxide.
' 7. A method according to claim 1 wherein said compound is the adduct of an amine oxide of the formula:
H g C 15H33- (BH- 0 Hz-N with two moles of ethylene oxide.
9 A'method according to cla'un'1 wherein said compound is the adduct of an amine oxide of the formula:
with 5 moles of ethylene oxide.
10. A method of softening fabrics which comprises contacting a fabric to be softened with an aqueous solution of an adduct of an amine oxide of the formula:
OH 0 R:
l T R4-OHOHr-N R: with n moles of ethylene oxide wherein R and R are selected from the group consisting of alkyl and hydroxyalkyl containing from 1 to 3 carbon atoms;
R is an alkyl group containing from 14 to 22 carbon atoms; and n is a small whole number from x, being the number of carbon atoms in R in excess of 12;
under conditions which will cause exhaustion of said compound onto said fabric.
HERBERT B. GUYNN, Primary Examiner US. Cl. X.R.
Po-1o5o Patent No., 3 ,501 335 Dated March 17, 197
flfiikrno Cahn! Thaddeus John Kaniecki, Oscar Walter Neiditch and Jerome Rudy It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 6, line 63, that portion of the formula MIMI more
reading "CH should read R2-'-5 that portion of the formula reading; "CH should read SHINE? AND SEA! EU si s-1970 mm B. JR. Oomissioner of Patents