US3756950A

US3756950A - Fabric softening compositions

Info

Publication number: US3756950A
Application number: US00122186A
Authority: US
Inventors: B Gluck
Original assignee: Lever Brothers Co
Current assignee: Lever Brothers Co
Priority date: 1971-03-08
Filing date: 1971-03-08
Publication date: 1973-09-04
Anticipated expiration: 1990-09-04

Abstract

A FABRIC SOFTENING COMPOSITION IS DISCLOSED WHICH INCORPORATES A CATIONIC FABRIC SOFTENING AGENT AND A WATERSOLUBLE ACID SALT OF AN AMPHOTERIC AMINO CARBOXYLIC ACID CHELATING AGENT TO DECREASE FABRIC YELLOWING CAUSED BY THE PRESENCE IN THE WATER USED OF DISSOLVED OR SUSPENDED METAL COMPOUNDS.

Description

United States Patent @1 Eco:

3,756,950 FABRIC SUF'IENING COMPOSITIONS Bruno Anthony Gluck, Hamburg, Germany, assignor to Lever Brothers Company, New York, NY.

No Drawing. Continuation-impart of abandoned application Ser. No. 746,324, July 22, 1968. This application Mar. 8, 1971, Ser. No. 122,186

Int. Cl. D06m 13/46 US. Cl. 252-8.75 12 Claims ABSTRACT OF THE DISCLOSURE A fabric softening composition is disclosed Which incorporates a cationic fabric softening agent and a watersoluble acid salt of an amphoteric amino carboxylic acid chelating agent to decrease fabric yellowing caused by the presence in the water used of dissolved or suspended metal compounds.

This is a continuation-in-part of my copending US. application Ser. No. 746,324, filed July 22, 1968, now abandoned.

This invention relates to fabric softening compositions incorporating cationic fabric softening agents.

There is a common tendency for fabrics treated with aqueous solutions of cationic softening agents to acquire a dull or yellowish appearance. This is believed to be caused by the presence in the water used of metal salts, including in particular iron salts, either in solution or as suspended solid particles.

It is an object of the present invention to provide a fabric softening composition having a decreased tendency to cause the dulling or yellowing of treated fabrics.

The fabric softening composition of the present invention comprises a cationic fabric softening agent and a water-soluble acid salt of an amphoteric amino-carboxylic acid chelating agent.

The compositions of the invention give a surprising improvement by way of decreased fabric yellowing due to their incorporating the acid salts of the chelating agents. This is believed to be due to the sequestering action of the acid salts on any metal ions, in particular iron, present in the water used. It has been found that the use of conventional chelating agents does not result in the decreased fabric yellowing desired.

Amphoteric amino-carboxylic acid chelating agents are well-known and readily available. Examples of such compounds are:

(i) nitrilo-triacetic acid (NTA) (ii) ethylene-diamine-tetracetic acid (EDTA) (iii) hydroxy-ethylene-diamine tetracetic acid (HEDTA) (iv) dihydroxy-ethyl glycine (DEG) (v) diethylene-triamino-pentacetic acid (DTPA) It will be seen from the above list that the expression amino-carboxylic acid chelating agent is used to include hydroxyamino-carboxylic acid chelating agents.

The acids used to form the salts of the amino-carboxylic acid chelating agents are preferably aliphatic carboxylic acids, which term is used to include hydroxy carboxylic acids, for example oxalic, citric, gluconic, tartaric, lactic and hydroxy-acetic acids.

The acid salts of the amino-carboxylic acid chelating agents can readily be obtained simply by mixing stoichiometric amounts of both components in aqueous solution. If desired, the salts can be obtained by crystallization from the aqueous solution. Alternatively, for practical purposes, it may be advantageous to use the aqueous solution of the acid salt directly. A simple way of preparing a suitable solution is to add to a solution of the amphoteric amino carboxylic acid chelating agent, which is usu- 3,756,950 Patented Sept. 4, 1973 ally available as its sodium salt, sutficient acid until a pH below its isoelectric point is reached.

Cationic fabric softening agents are well known and are commercially available. They are nitrogenous compounds such as the quaternary ammonium type having four alkyl or substituted alkyl groups of differing chain lengths attached to a nitrogen atom. Typical representative, but not limiting, examples of quaternary ammonium fabric softenmg agents are:

[H -N-Ih] X l. 2 6B [Br-N-CHz-Q] x it,

3 [Br-CO-NH-lh-bf 1 X R4CONHR5-N-RB e X I O R -CONHR NRo y HN Jim] x oH3-0oNH-R, 0 y R4- -N G3 I: N 4:11,] X 1 y (7) Diethyl aminoethanol-stearamide-ethyl sulfates; (8) The reaction product of 2 moles of an acid of the formula R COOH and an alkylene diamine of the formula:

In the foregoing formulas, R is an aliphatic hydrocarbon group containing from 16 to 20 carbon atoms; R is an alkyl group containing from 1 to 3 carbon atoms; R is selected from the group consisting of R and R R is an aliphatic hydrocarbon group containing from 15 to 19 carbon atoms; R is an alkylene group containing 2 carbon atoms; R is a hydroxy-alkyl group containing from 1 to 3 carbon atoms; R, is an alkyl group of 1 to 3 carbon atoms; X is an anion selected from the group consisting of halides, sulfates, alkyl sulfates having 1 to 3 carbon atoms in the alkyl group, and acetates, and y is the valency of X.

The anion portion of the long chain quaternary ammonium compounds (1) may be a halide, particularly chloride, bromide, or iodide, a sulfate or an alkylsulfate such as methyl sulfate, or an acetate.

Preferred long chain quaternary ammonium compounds (1) for use in this invention have two long chain aliphatic and two lower alkyl groups. Typical compounds are dihexadecyl dimethyl ammonium bromide, distearyl diethyl ammonium chloride, distearyl dipropyl ammonium chloride and ditallow dimethyl ammonium methyl sulfate, quaternary ammonium compounds containing three longchain aliphatic groups may also be used, but lesser quantities may be required, as the fabric conditioning properties are affected by the number of long-chain aliphatic groups. A typical compound of this category is tristearyl monomethyl ammonium chloride.

The fatty acid amides, Compound (8), which may be used in the preferred embodiment are the products of the reaction of one mole of a long-chain fatty acid with two moles of a hydroxyalkyl alkylene diamine. The longchain fatty acid should contain from 16 to carbon atoms as described above with respect to the long-chain aliphatic hydrocarbon portions of the quaternary ammonium compounds (1). The hydroxyalkyl group may contain from 1 to 3 carbon atoms, typical groups being methanol, ethanol and propanol radicals. The alkylene group is ethylene, The preferred compounds contain about 2 fatty acid groups, having a nominal formula such as N,N'-distearoyl-N-hydroxyethyl ethylene diamide. While the reaction product of the fatty acid and alkanol alkylene diamine is nominally a diamide, spectral analysis shows that a number of chemical species are present in the material. A typical analysis indicates that the product contains about percent cationics such as imidazolines, and the balance being esters and amides.

Representative fabric softeners which may be used in accordance with the foregoing include, but are not limited to, dimethyl distearyl [or di-(hydrogenated tallow)] ammonium chloride, bromide, iodide, sulfate, methylsulfate and acetate; dimethyl-N-alkyl (C -C benzyl ammonium chloride, bromide, iodide, sulfate, methylsulfate and acetate; N-methyl-N-(2-hydroxyethyl)-N-(2-hydroXy dodecyl)-N-benzyl ammonium chloride, bromide, iodide, sulfate, methylsulfate, and acetate; and N,N-dimethyl-N- dodecyl-(2-hydroxy ethyl) ammonium chloride, bromide, iodide, sulfate, methylsulfate, and acetate. In the foregoing compounds the dodecyl moieties referred to can be replaced by higher molecular weight alkyl moieties as is well known in the art.

Other well-known fabric softening agents include 1-(2- alkylamido ethyl)-2-alkyl imidazoline salts, salts of heptadecyl imidazoline, and alkylamido alkylene pyridinium chloride.

The composition of the invention may be a dry composition if desired. However, it is generally more convenient both for the manufacturer and for the user to form a solution for fabric treatment if the composition is sold as a concentrated aqueous solution or suspension of the cationic fabric softening agent and the acid salt of the amino carboxylic acid chelating agent. In this connection it has been found that when a concentrated aqueous solution of an acid salt is added to melt of a fabric softening agent and thoroughly stirred, a semi-solid paste is obtained on cooling which subsequently can be dispersed in water and used for effective fabric treatment.

The ratio of the cationic fabric softening agent to the acid salt of the amino-carboxylic acid chelating agent is generally within the range of from 20:1 to 4:1 and is preferably about 10:1. In a liquid composition, for subsequent dilution on use, the concentration of the cationic fabric softening agent is normally within the range of from about 2 to about 20 percent, preferably about 10 percent, by weight and the concentration of the acid salt is normally within the range of from about 0.2 to about 5 percent, preferably about 1 percent, by weight.

The aqueous solutions of the compositions when used for fabric treatment may be made with different concentrations of the composition in water, but a concentration of about 0.2 percent of a liquid composition, or an equivalent concentration of a solid composition, is generally satisfactory. The resultant concentrations of the fabric softening agent and the acid salt are then generally within the ranges of from about 0.005 to 0.05 and from about 0.0005 to 0.01 percent, by weight, respectively.

It will be appreciated that the compositions of the invention may include, in addition to the essential ingredients, minor amounts of conventional optional additives, including, for example, colorants, perfumes, thickeners, fluorescent agents, inorganic salts and anti-redeposition agents such as sodium carboxymethylcellulose.

Fabric softening compositions according to the invention are illustrated by the following examples, in which parts and percentages are by weight:

EXAMPLE I To a solution of 38.0 parts of the tetrasodium salt of EDTA in 100 parts of water, 38.4 parts of anhydrous citric acid were added with stirring until a clear solution was obtained. It was found that crystals of the citric acid salt could be isolated by concentration of the solution.

A fabric softening composition was then prepared by admixture of the following ingredients:

Parts Di-stearyl dimethyl ammonium chloride 7.5

Colorant 0.0005 The acid salt solution prepared as described above 1.0

Water to 100.0.

The resultant composition was found to be an effective softening agent for textile fabrics and had a decreased tendency to cause yellowing of the fabric when used in aqueous solution in water containing dissolved iron salts, in comparison with a similar composition not containing the acid salt.

EXAMPLE II To 100 parts of an aqueous paste concentration) of distearyl-dimethyl-ammonium chloride heated to a temperature of approximately 70 C., 10 parts of the solution prepared as described in Example I were added with thorough stirring and the product was allowed to cool. The resultant composition can be used by dispersion in water to make up a formulation similar to that described in Example I.

EXAMPLE III A fabric softening composition was prepared with the following formulation:

Percentage l-methyl 1 alkylamido ethyl-2-alkylimidazolonium methosulfate 7.5. Citric acid salt of EDTA 2 1.05. Colorant About 0.002. Perfume About 0.075. Water To 100.00.

noisolgasirlfd as Culsoft S75 from Culver Chemical 00., Illi- -Added as an aqueous solution containing 10% of EDTA and 10% of citric acid salt of EDTA.

Samples of three fabrics-cotton sheeting, terry toweling and woven nylon-were treated as follows with the compositions prepared above after firstly washing the fabrics in a washing machine using a conventional anionic detergent composition. The washed fabrics were wrung and then twice hand rinsed in cold water and finally rinsed with an aqueous solution (0.2% concentration) of one of the compositions described above. Samples of the fabrics were also similarly washed and then rinsed without using a fabric softening agent. The cold water used contained about 30 ppm. of hardness salts (calculated as CaCO and 40 p.p.m. of suspended solids.

The fabrics so treated were examined for softness and appearance by a large number of people with the following results:

Proportion of bries considered softest,

Fabric softening composition percent Appearance N 0 composition used 0 Least yellowing.

EXAMPLES IV AND V Compositions incorporating the citric acid salt of EDTA were prepared with formulations similar to that in Example III with the exception that the cationic softening agent was replaced in these examples, respectively, by di-(hydrogenated)tallow dimethyl ammonium chloride (obtained as Arquad 2HT from Armour Hess Chemicals Ltd., Great Britain) and a substituted tetramine-amido diacetate (obtained as Kem-Soft 12/252 from Chemical Materials Ltd., Sydney, Australia).

Both compositions were found to be effective for the softening of fabrics and imparted little yellowing to the fabrics even when used with water containing a high proportion of dissolved and suspended metal salts.

EXAMPLE VI A composition was prepared by a procedure similar to Example I with the exception that the citric acid was replaced by an equimolar amount of gluconic acid. The composition was satisfactory for fabric softening with decreased fabric yellowing compared with a composition containing no acid salt.

EXAMPLE VII In order to demonstrate the surprising advantage of the use of a carboxylic acid salt of an aminocarboxylic acid chelating agent, in comparison with the use separately of the components of the salt, both of which can be used alone as chelating agents, and the use alone of the fabric softening agent, four compositions were made as follows:

Percentage Composition- A B 3 C D Ingredient:

Fabric softening agent 7. 5 7. 6 7. 5 7. 5

Citric acid salt of EDTA 1. 05

EDTA Y 1. 05

Citric acid 1. 05

Water to 100 100 100 100 Percent Percent fabric fabric Composition softening yellowing It can be seen that the least fabric yellowing is obtained using the composition of the invention, with a slight decrease in fabric softening in comparison with the use of the fabric softening agent alone. The use of EDTA or citric acid separately gives no decrease in fabric yellowing and a considerable decrease in fabric softening.

It will be appreciated that the foregoing examples are provided for the purpose of illustration and are not to be taken as limiting the invention thereto. Whilst the preferred acid salt of an amphoteric aminocarboxylic acid used in the composition of the present invention is the .salt of EDTA and citric acid, other acid salts are used effectively in the compositions of the invention, particularly the salts of EDTA with oxalic, gluconic, tartaric, lactic or hydroxyacetic acids and of NTA, HiEDTA, DEG, and DTPA with any of the same acids or citric acid.

I claim:

1. \A fabric softening composition comprising:

(a) at least one cationic nitrogenous compound as an active fabric softening agent which tends to cause yellowing in the presence of dissolved or suspended metal compounds; and

(b) an acid addition salt of an amphoteric amino carboxylic acid chelating agent selected from the group consisting of nitrilo-triacetic acid, ethylene-diaminetetracetic acid, dihydroxy-ethyl glycine, and diethylenetriarninopentacetic acid with an aliphatic carboxylic acid selected from the group consisting of oxalic acid, citric acid, gluconic acid, tartaric acid, lactic acid and hydroxyacetic aid, there being 1 part by weight of said water-soluble acid addition salt for each 4 to 20 parts by weight of said cationic nitrogenous compound.

2. The composition according to claim 1 wherein said amino carboxylic acid is ethylene diamine tetracetic acid and said aliphatic carboxylic acid is citric acid.

3. A fabric softening composition comprising (a) at least one cationic nitrogenous fabric softening agent which tends to cause yellowing in the presence of dissolved or suspended metal compounds, said cationic nitrogenous fabric softening agent being selected from the group consisting of:

R I I-R X 1'1.

[R.I I-cm:| X 2 1! (m) [Br-CO-NH-Rr-NQ x Rr-C 0-NH-R,-r I-R, e

O X RiOONHR I I-R9 y R4C=N ca m x on, x cn,-co-NH-R. oil,

(Vi) R4C:N

Hi l nn x 7 CQ 5! (vii) diethyl amino ethanol-stearamide-ethyl sulfates; and

(viii) the reaction product of 2 moles of an acid of the formula R COOH and an alkylene diamine of the formula:

said reaction product comprising a mixture of imidazolines, esters and amides, wherein R is an aliphatic hydrocarbon group containing from 16 to 20 carbon atoms; R is an alkyl group containing from 1 to 3 carbon atoms; R is selected from the group consisting of R and R R is an aliphatic hydrocarbon group containing from 15 to 19 carbon atoms; R is a hydroxy-alkyl group containing from 1 to 3 carbon atoms; R, is an alkyl group of 1 to 3 carbon atoms; X is an anion selected from the group consisting of halides, sulfate, alkyl sulfates having 1 to 3 carbon atoms in the alkyl group, and acetate, and y is the valency of X;

and (b) an acid addition salt of an amphoteric amino carboxylic acid chelating agent selected from the group consisting of nitrilo-triacetic acid, ethylene-diaminetetracetic acid, dihydroxy-ethyl glycine, and diethylenetriamino-pentacetic acid with an aliphatic carboxylic acid selected from the group consisting of oxalic acid, citric acid, gluconic acid, tartaric acid, lactic acid and hydroxy-racetic acid, there being 1 part by weight of said Water-soluble acid addition salt for each 4 to 20 parts by weight of said cationic nitrogeneous compound.

4. A fabric softening composition comprising: (a) from about 4 to about 20 parts by weight of a cationic fabric softening agent selected from the group consisting of:

dimethyl distearyl ammonium chloride,

dimethyl distearyl ammonium bromide,

dimethyl distearyl ammonium iodide,

dimethyl distearyl ammonium sulfate,

dimethyl distearyl ammonium methyl sulfate,

dimethyl distearyl ammonium acetate;

di-(hydrogenated) tallow ammonium chloride,

di-(hydrogenated) tallow ammonium bromide,

di-(hydrogenated) tallow ammonium iodide,

di-(hydrogenated) tallow ammonium sulfate,

di-(hydrogenated) tallow ammonium methyl sulfate,

di-(hydrogenated) tallow ammonium acetate;

climethyl-N-alkyl (C -C benzyl ammonium chloride,

dimethyl-N-alkyl (C -C benzyl ammonium bromide,

dimethyl-N-alkyl (C -C benzyl ammonium iodide,

dimethyl-N-alkyl (C -C benzyl ammonium sulfate,

dimethyl-N-alkyl (C -C benzyl ammonium methyl sulfate,

dimethyl-N-alky1 (C -C benzyl ammonium acetate;

N-methyl-N- (Z-hydroxyethyl) -N- 2-hydroxy dodecyD-N-ammonium chloride,

N-methyl-N- Z-hydroxyethyl) -N- (Z-hydroxy dodecyl)-N-ammonium bromide,

N-methyl-N- (2-hydroxyethyl -N- 2-hydroxy dodecyl)-N-ammonium iodide,

N-methyl-N- (2-hydroxyethyl) -N- (Z-hydroxy dodecyl)-N-ammonium sulfate,

N-methyl-N-(Z-hydroxyethyl)-N-(2-hydroxy dodecyl)-N-ammonium methyl sulfate,

N-methyl-N- (2-hydroxyethyl -N-( 2-hydroxy dodecyl)-N-ammonium acetate;

N,N-dimethyl-N-dodecyl- (2-hydroxyethyl ammonium chloride,

N,N-dimethyl-N-dodecyl-(2-hydroxyethy1)- ammonium bromide,

N,N-dimethyl-N-dodecyl- (2-hydroxyethyl) ammonium iodide,

N,N-dimethylN-dodecyl-(2-hydroxyethyl)- ammonium sulfate,

N,N-dimethyl-N-dodecyl- (2-hydroxyethyl ammonium methyl sulfate,

N,N-dimethyl-N-dodecyl- (Z-hydroxyethyl ammonium acetate;

1-(2-alkylamidoethyl)-2-alkyl imidazoline salts;

heptadecyl imidazoline salts;

the reaction product of about 2 moles of C C fatty acid with a hydroxy alkyl ethylene diamine containing from 1 to 3 carbon atoms in the hydroxy alkyl group, said reaction product being a mixture of amides, esters, and imidazolines; and

alkylamido alkylene pyridinium chlorides; and

(b) about 1 part by weight of a water-soluble salt of an amphoteric amino-carboxylic acid chelating agent selected from the group consisting of nitrilo-triacetic acid, ethylene diamine tetracetic acid, diethylene triamino pentacetic acid, and dihydroxyethyl glycine,

with an aliphatic carboxylic acid selected from the group consisting of oxalic acid, tartaric acid, citric acid, gluconic acid, lactic acid and hydroxyacetic acid.

5. A fabric softening composition according to claim 4 wherein the amino-carboxylic acid is ethylene diamine tetracetic acid and the aliphatic acid is citric acid.

6. A fabric softening composition according to claim 4 containing about 10 percent by weight of the cationic fabric softening agent and about 1 percent by weight of the acid salt of the amphoteric amino-carboxylic acid chelating agent.

7. A fabric softening composition according to claim 4 containing from about 2 to about 20 percent by weight of the cationic fabric softening agent, from about 0.2 to about 5 percent by weight of the acid salt of the amphoteric amino-carboxylic acid chelating agent and the balance being substantially water.

8. A fabric softening composition according to claim 7 wherein the amino-carboxylic acid is ethylene diamine tetracetic acid and the aliphatic carboxylic acid is citric acid.

9. In a method of softening fabrics wherein the fabric to be softened is treated with an aqueous solution containing at least one cationic nitrogenous compound as an active fabric softening agent which tends to cause yellowing in the presence of dissolved or suspended metal compounds, the improvement comprising adding to the solution an acid addition salt of an amphoteric amino carboxylic acid chelating agent selected from the group consisting of nitrilo-triacetic acid, ethylene-diamine-tetracetic acid, dihydroxy-ethyl glycine, and diethylene-triaminopentacetic acid, with an aliphatic carboxylic acid selected from the group consisting of oxalic acid, citric acid, gluconic acid, tartaric acid, lactic acid and hydroxy-acetic acid, there being 1 part of said water-soluble acid addition salt for each 4 to 20 parts by weight of said cationic nitrogenous compound, and then treating the fabric with said aqueous solution.

10. A method of softening fabrics in accordance with claim 9 wherein said amino carboxylic acid is ethylene diamine tetracetic acid and said aliphatic carboxylic acid is citric acid.

11. A method according to claim 9 in which the cationic nitrogenous compound comprises from about 0.005 percent to about 0.05 percent by weight of said aqueous solution and said addition salt comprises from about 0.0005 percent to about 0.01 percent by weight of said aqueous solution.

12. In a method of softening fabrics wherein the fabric to be softened is treated with an aqueous solution containing at least one cationic nitrogenous compound as an active fabric softening agent which tends to cause yellowing in the presence of dissolved or suspended metal compounds, said cationic nitrogenous fabric softening agent being selected from the group consisting of:

[ -i- QT (iii) 9 10 (v) e 3 carbon atoms in the alkyl group, and acetate, and 1 X9 Y is the valency of X, the improvement comprising adding to the solution an acid addition salt of an as C a v amphoteric amino carboxylic acid chelating agent se- M) a) 5 lected from the group consisting of nitrilo-triacetic 6 acid, ethylene-diamine-tetracetic acid, dihydroxy- E H1 x ethyl glycine, and diethylenetriamino-pentacetic acid R1 0 2 y with an aliphatic carboxylic acid selected from the group consisting of oxalic acid, citric acid, gluconic gg ammo ethanol Steammlde ethyl sulfates 10 acid, tartaric acid, lactic acid and hydroxyacetic acid, (viii) the reaction product of 2 moles of an acid of t? 1 part by weight of said water'sc'hfble the formula R COOH and an alkylene diamine of a m f each 4 to 20 Parts by welght the formula: of said cationic nitrogenous compound, and then H R. treating the fabric with said aqueous solution.

NO2H4-N References Cited n UNITED STATES PATENTS said reaction product comprising a mixture of imid- 2,584,017 1/1952 Dvorkovitz et a1. 252152 X azolines, esters and amides, wherein R is an aliphatic 2,742,434 4/ 1956 Kopp 252137 X hydrocarbon group containing from 16 to 20 carbon 20 3,154,489 10/ 1964 Dubrow et a1 252--8.8 X atoms; R is an alkyl group containing from 1 to 3 3,325,414 6/1967 Inamorato 252137 carbon atoms; R;, is selected from the group consist- 3,447,965 6/1969 Teumac 134--2 ing of R and R R is an aliphatic hydrocarbon group containing from 15 to 19 carbon atoms; R HERBERT G'UYNN, 'y EXamll'lel' is a hydroxy-alkyl group containing from 1 to 3 carbon atoms; R-; is an alkyl group of 1 to 3 carbon atoms; X is an anion selected from the group con- 117 139 5 'CQ; 252 8,8, UK}, 11

sisting of halides, sulfate, alkyl sulfates having 1 to UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,756,950 Dated gggmmhg'r g 1913" "Inventor(s) Bruno Anthony Gluck It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line '52', "diamine tetracetic" should read dlamine-tetracetic Col. 2, line '34, "aminoethanol" should read amino et ano Col. 2, line 171,1 "Compound" should read compound Col. 5,-line 37 (Footnote 1) "imidazolinium'? should read imidazolonium Col. 6, line 11, "aid" should read acid Col. 8, li-nesv6265, should be corrected to read Signed and sealed this 13th day of August 1974.

(SEAL) Attest Z McCOY M. GIBSON, JR.. C. MARSHALL DANN Attesting Officer Commissioner of Patents