Silicone Fatty Esters

1. Field of the Invention

The present invention relates to a series of novel silicone fatty esters which provide outstanding lubrication, and softening when applied to a variety of fiber substrates. The esterification by which the compounds are prepared involves the reaction of a hydroxyl containing silicone polymer, and a fatty acid, ester or anhydride.

2. Arts and Practices

Silicone compounds have been known to be active at the surface of cellulosic and synthetic fibers as well as paper. They are good nondurable lubricants and are very stable to oxidation, however, their high cost and lack of efficiency at low concentrations as well as low durability have made their acceptance in commercial products quite low.

In addition to their high cost, silicone compounds have little or no solubility in mineral oils, fatty triglycerides and other classical fatty quatarnary compounds used for softening. This has resulted in the inability to prepare stable blends for use as a textile fiber treatment.

In many applications, there is a desire for a more fatty soluble softener. The desired molecule should have the desirable softening and antistatic properties of silicone, yet have compatibility with traditional fatty materials and oils. Even though a textile softener which has both the desirable softening and antistatic properties of silicone as well as compatibility with fatty compounds has been a long felt need, it isn't until the compounds of the present invention that such a system has been attained.

U.S. Pat. No. 3,511,699 to Sterman issued May 12, 1970 teaches that epoxy compounds placed in the silicone backbone by hydrosilation can be cured onto certain fibers to give improved substantivity. The substantivity is based upon the reaction of hydroxyl groups on the cellulosic and the epoxy group in the silicone polymer. The resulting bond is a ether linkage and a new hydroxyl group. While a definite improvement over other compounds the efficiency and durability of the were not good enough to allow for cost effective incorporation of these materials in detergent formulations.

It is the object of the present invention to provide novel silicone based fatty ester compounds which are substantive to the surface of a fiber and other textile materials including cellulosic material and have increased solubility in fatty materials including mineral oil, fatty triglycerides and traditional fatty quaternary ammonium compounds. The compounds of the present invention render the lubricity, and hydrophobicity generally seen in silicone compounds, but because they are esterified with fatty groups have greater solubility in hydrocarbon oils as well as fatty materials than the traditional silicone compounds which are insoluble in those materials.

It is another objective of the current invention to provide silicone fatty esters which can be used in textile, formulations to render softness and lubrication to the substrates being treated. The superior antistatic properties are an important benefit, since this is a major aspect of consumer perception of softness in consumer and industrial laundry applications. Application of the compounds of the invention can be from solvent, aqueous dispersion or solution, or applied neat in these processes.

The present invention relates to novel silicone fatty ester compounds. The compounds by virtue of the fatty ester group are soluble in fatty and hydrocarbon products, but have many of the functional softening and lubrication properties of silicone. This property makes these materials excellent additives for highly effective surface modifying finishes for fiber and textiles. The compounds of the present invention are substantive to cellulosic and synthetic fibers as well as metal surfaces and plastic polymers.

The compounds of this invention are silicone fatty esters made by the esterification of a fatty acid, ester, or anhydride and a hydroxy containing silicone compound. The compounds of the present invention conform to the following structure; ##STR1## wherein; R is alkyl having 1 to 20 carbon units;

R.sup.1 is selected from lower alkyl CH.sub.3 (CH)n-- or phenyl;

n is an integer from 0 to 8;

a, b and c are integers independently ranging from 0 to 20;

EO is an ethylene oxide residue --(CH.sub.2 CH.sub.2 --O)--;

PO is a propylene oxide residue --(CH.sub.2 CH(CH.sub.3)--O)--;

o is an integer ranging from 1 to 100;

q is an integer ranging from 0 to 500.

In a preferred embodiment, R is CH.sub.3 --(CH.sub.2).sub.16 -- and is derived from stearic acid.

The compounds of the present invention are prepared by the reaction of a hydroxy silicone compound and a fatty acid. Examples of suitable reactants are as follows;

Union Carbide Chemicals and Plastics, Danbury, Conn., offers a series of hydroxy silicone compounds suitable for use as raw materials in the preparation of the esters of the present invention. These materials are marketed under the SILWET trade name.

The preferred method of placing this type of reactive hydroxyl group into the silicone polymer is by the reaction of silanic hydrogen containing polymer with allyl alcohol alkoxylates. This technology is well known to those skilled in the art and are described in U.S. Pat. No. 4,083,856. These hydroxyl functional silicone compounds are subsequently esterified, by reaction with fatty acids, esters or anhydrides, to make the compounds of the present invention.

Additionally, hydroxy silicone compounds are available from Siltech Inc. Norcorss, Ga. These compounds conform to the following generic structure;

The esterification can be carried out without catalyst; however, when no catalysts are used reaction rates are less efficient. Standard esterification catalysts are generally used at concentrations of between 0.05% to 0.50% with a preferred range of 0.1% to 0.3%. Catalysts which are effective include but are not limited to; sulfuric acid, p-toluene sulfonic acid, methane sulfonic acid, tin metal, zinc metal, titanium metal, organo titianates, organo tin compounds, organo zinc compounds, zinc oxide, magnesium oxide, calcium oxide, etc. The most preferred catalyst is stannous oxylate. The reaction is conducted at between 140 and 240 C. under an inert nitrogen blanket. The nitrogen blanket preserves the color. Preferred temperature range is between 180 and 210 C. Water is removed from the reaction which is done using a nitrogen sparge or vacuum.

The reaction can be run with either a stiochiometric amount of the fatty acid, or a slight excess of either reactant.

Into a suitable round bottom, three neck flask equipped with a Dean Stark trap, a thermometer and a nitrogen sparge is added 284.0 grams of stearic acid, 0.25% by weight of the total batch charged of stannous oxylate and 2,39 grams of Siltech H 1000. The reaction mass is blanketed with nitrogen, and heated to 180 and 200 C. under an inert nitrogen blanket. Once the reaction temperature reaches 120 C. water begins to boil off and is collected in the Dean Stark Trap. Within four to five hours the theoretical water is collected off and the acid value is very low. The product is a clear liquid and is used without additional purification.

Example 1 is repeated only this time substituting the specified number of grams of the fatty acid specified for the stearic acid and the specified type and number of grams of silicone compound as shown below:

Compounds of this invention were compared to standard compounds commercially available using AATCC Test Method 117-1979. The color fastness heat test uses a 400 F. (205 F.) hot iron which is applied for 60 and 180 seconds. The color is rated on a 1-5 basis for yellowness, (5 being the most yellow).

As can be seen the compounds of the present invention are non-yellowing softeners when compared to standard softeners.

As can be easily seen the compounds of the present invention are excellent lubricants.