Silicone esters of hydroxy acid

Abstract

The invention relates to a series of novel silicone esters of hydroxy acids. The compounds of the present invention are prepared by reacting a the hydroxyl group in a silicone polymer with a hydroxy acid selected from the group consisting of lactic acid and glycolic acid. The compounds of the present invention find use in skin care products and other personal care products.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to a series of novel silicone esters prepared by the esterification reaction of a dimethicone copolyol and a hydroxy acid selected from the group consisting of lactic and glycolic acid. These materials provide outstanding skin feel and lubrication as well as emmoliency properties. The compounds of the present invention are prepared by reacting a hydroxyl containing silicone polymer, and a hydroxy acid selected from the group consisting of lactic acid and glycolic acid.

ARTS AND PRACTICES

Silicone fluids have been known to be good oily additives to cosmetic products. They are good nondurable oily materials.

They are very stable to oxidation, however, their use has been restricted to those applications where oily materials are needed.

In many applications, there is a desire for a silky skin feel. The desired molecule should have the desirable dry feel and yet have mildness and durability of silicone oils.

THE INVENTION

OBJECT OF THE INVENTION

It is the object of the present invention to provide novel silicone ester which are prepared by the esterification reaction of a hydroxy acid selected from the group consisting of lactic and glycolic acid with a dimethicone copolyol. These compounds are substantive to the skin giving a dry talc like feel to the skin, are non-irritating, and provide emmoliency properties to the skin.

It is another objective of the current invention to provide silicone hydroxy acid esters which can be used in personal care products, more specifically skin care products.

SUMMARY OF THE INVENTION

The present invention relates to novel silicone ester which is prepared by the esterification reaction of a hydroxy acid selected from the group consisting of lactic and glycolic acid with a dimethicone copolyol. The compounds by virtue of the fatty hydroxy containing ester group are provide unique skin feel and emmoliency properties to the skin when applied in a variety of personal care products.

As will become clear from the disclosure, the compounds of the present invention while having silicone present in the molecule, have unique skin feel which is a direct result of the structure. The pendant group needs to contain (a) a silicone atom linked covalently through carbon to (b) an alkoxylated portion linked covalently to (c) an ester function, linked covalently to (d) a hydroxy containing group selected from the group consisting of lactic and glycolic acid. Compounds lacking these functional parts do not give the desired dry feel and emmoliency.

The compounds of the present invention are prepared by the by the esterification reaction of a hydroxy acid selected from the group consisting of lactic and glycolic acid with a dimethicone copolyol.

The compounds of this invention are by the esterification reaction of a hydroxy acid selected from the group consisting of lactic and glycolic acid with a dimethicone copolyol. In a preferred embodiment the dimethicone is selected from the group consisting of

(a) terminal dimethicone copolyols which conform to the following structure; ##STR1## wherein; Me is methyl; R' is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b--(EO).sub.c --H EO is --(CH.sub.2 CH.sub.2 --O)--; PO is a --(CH.sub.2 CH(CH.sub.3 )--O)-- o is an integer ranging from 1 to 100; and (b) comb dimethicone copolyols which conform to the following structure; ##STR2## wherein; Me is methyl; R is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H EO is --(CH.sub.2 CH.sub.2 --O)--; PO is a --(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 one preferred embodiment the compounds of the invention conform to the following structure; ##STR3## wherein; Me is methyl; R.sup.1 is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --C(O)--R.sup.2 R.sup.2 is selected from the group consisting of CH.sub.3 --CH(OH)-- and HO--CH.sub.2 --; o is an integer ranging from 1 to 100; EO is --(CH.sub.2 CH.sub.2 --O--; PO is a --(CH.sub.2 CH(CH.sub.3)--O)--. In another preferred embodiment the compounds of the invention conform to the following structure; ##STR4## wherein; R.sup.1 is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --C(O)--R.sup.2 R.sup.2 is selected from the group consisting of CH.sub.3 --CH(OH)-- and HO--CH.sub.2 --; Me is methyl; EO is --(CH.sub.2 CH.sub.2 --O--); PO is a --(CH.sub.2 CH(CH.sub.3)--O)-- o is an integer ranging from 1 to 100; R.sup.1 is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --C(O)--R.sup.2 R.sup.2 is selected from the group consisting of CH.sub.3 --CH(OH)-- and HO--CH.sub.2 --.

EXAMPLES

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

REACTANTS

Hydroxy Acids

The hydroxy acids useful as raw materials for the preparation of the compounds of the present invention are commercially available. They are;

______________________________________Lactic Acid CH.sub.3 --CH(OH)C(O)--OHGlycolic Acid HO--CH.sub.2 --C(O)--OH______________________________________

Hydroxy Silicone Compounds

Many manufacturers offer 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 many trade names. Siltech Inc, Union Carbide, Dow Corning, Mazer and many other manufacturers also offer the compounds commercially.

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 reacted with hydroxy acids, to make the compounds of the present invention.

Additionally, hydroxy silicone compounds are available from Siltech Inc. Norcross Ga. These compounds conform to the following generic structure; ##STR5## wherein; Me is methyl;

R.sup.5 is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H R.sup.1 is selected from lower alkyl CH.sub.3 (CH).sub.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. ______________________________________Example Name a b c o q______________________________________1 Siltech H 1000 3 0 0 2 542 Siltech H 1100 10 5 10 10 1003 Siltech H 1200 20 20 20 2 564 Siltech H 1300 10 10 10 6 265 Siltech H 1400 0 10 0 4 2006 Siltech H 1500 5 5 5 2 507 Siltech H 1600 0 6 0 10 258 Siltech H 1700 0 0 0 5 10______________________________________

Terminal Substituted Dimethicone Copolyol Compounds

Terminal substituted dimethicone copolyol compounds are well known and are marketed in the trade under many names.

The preferred method of placing this type of reactive hydroxyl group into the silicone polymer is by the reaction of terminal 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 materials are available from Siltech Inc. Norcross Ga. and are marketed under the Siltech T series trade name. ##STR6## wherein; Me is methyl;

R.sup.6 is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H R.sup.1 is selected from lower alkyl CH.sub.3 (CH).sub.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. ______________________________________ Equivalent MolecularExample Name a b c Weight______________________________________ 9 Siltech T 701 0 0 0 1,00010 Siltech T 706 5 1 0 6,00011 Siltech T 710 2 1 1 10,00012 Siltech T 750 10 5 10 50,00013 Siltech T 790 20 20 20 86,000______________________________________

General Reaction Conditions

The reaction can be run with either a stiochiometric amount of the hydroxy acid or with an excess of silicone polymer. 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.

Example 14

Into a suitable round bottom, three neck flask equipped with a thermometer and a nitrogen sparge is added 1,000 grams of the silicone compound example 1 and the 90.0 grams of lactic acid. The reaction mass is blanketed with nitrogen, and heated to 180 and 210 C. under the inert nitrogen blanket.

Water is distilled off. Within four to five hours the acid value is vanishingly low. The product is a clear liquid and is used without additional purification.

Examples 15-32

Example 14 is repeated only this time substituting the specified number of grams of the specified hydroxy acid and the specified type and number of grams of silicone compound as shown below;

______________________________________ Hydroxy Silicone ReactantExample Acid Grams Example Grams______________________________________15 Lactic 90.0 1 2,329.016 Lactic 90.0 2 2,032.017 Lactic 90.0 3 5,129.018 Lactic 90.0 4 347.619 Lactic 90.0 5 4,407.020 Lactic 90.0 6 2,743.021 Lactic 90.0 7 3,550.822 Lactic 90.0 8 1,512.423 Lactic 90.0 9 1,000.024 Lactic 90.0 10 6,000.025 Lactic 90.0 11 10,000.026 Lactic 90.0 12 50,000.027 Lactic 90.0 13 86,000.028 Glycolic 76.0 1 2,329.029 Glycolic 76.0 2 2,032.030 Glycolic 76.0 3 5,129.031 Glycolic 76.0 4 347.632 Glycolic 76.0 5 4,407.033 Glycolic 76.0 6 2,743.034 Glycolic 76.0 7 3,550.835 Glycolic 76.0 8 1,512.436 Glycolic 76.0 9 1,000.037 Glycolic 76.0 10 6,000.038 Glycolic 76.0 11 10,000.039 Glycolic 76.0 12 50,000.040 Glycolic 76.0 13 86,000.041 Lactic 45.0 1 2,329.042 Lactic 45.0 2 2,032.043 Lactic 45.0 3 5,129.044 Lactic 45.0 4 347.645 Lactic 45.0 5 4,407.046 Lactic 45.0 6 2,743.047 Lactic 45.0 7 3,550.848 Lactic 45.0 8 1,512.449 Lactic 45.0 9 1,000.050 Lactic 45.0 10 6,000.051 Lactic 45.0 11 10,000.052 Lactic 45.0 12 50,000.053 Lactic 45.0 13 86,000.054 Glycolic 36.0 1 2,329.055 Glycolic 36.0 2 2,032.056 Glycolic 36.0 3 5,129.057 Glycolic 36.0 4 347.658 Glycolic 36.0 5 4,407.059 Glycolic 36.0 6 2,743.060 Glycolic 36.0 7 3,550.861 Glycolic 36.0 8 1,512.462 Glycolic 36.0 9 1,000.063 Glycolic 36.0 10 6,000.064 Glycolic 36.0 11 10,000.065 Glycolic 36.0 12 50,000.066 Glycolic 36.0 13 86,000.0______________________________________ The compounds of the present invention were found to have a silky talc like feel when applied to skin. They have been found to have low toxicity when applied to the skin and eyes, and non-toxic when ingested.

Claims

1. A silicone ester prepared by the esterification reaction of a hydroxy acid selected from the group consisting of lactic and glycolic acid with a dimethicone copolyol.

2. A compound of claim 1 wherein the dimethicone is selected from the group consisting of

(a) terminal dimethicone copolyols which conform to the following structure; ##STR7## wherein; Me is methyl;

R' is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H

EO is --(CH.sub.2 CH.sub.2 --O)--;

PO is a --(CH.sub.2 CH(CH.sub.3)---O)--

is an integer ranging from 0 to 20;

b is an integer ranging from 0 to 20;

c is an integer ranging from 0 to 20;

o is an integer ranging from 1 to 100; and

(b) comb dimethicone copolyols which conform to the following structure; ##STR8## wherein; Me is methyl;

R is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H;

o is an integer ranging from I to 100;

q is an integer ranging from 0 to 500;

EO is --(CH.sub.2 CH.sub.2 --O)--;

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

a is an integer ranging from 0 to 20;

b is an integer ranging from 0 to 20;

c is an integer ranging from 0 to 20.

3. A silicone polymer of claim 2 wherein said dimethicone copolyol conform to the following structure; ##STR9## wherein; Me is methyl;

R' is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H;

o is an integer ranging from 1 to 100;

EO is --(CH.sub.2 CH.sub.2 --O)--;

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

a is an integer ranging from 0 to 20;

b is an integer ranging from 0 to 20;

c is an integer ranging from 0 to 20.

4. A silicone polymer of claim 2 wherein said dimethicone copolyol conform to the following structure; ##STR10## wherein; Me is methyl;

R is --(CH.sub.2).sub.3 --O--(EO).sub.a --(PO).sub.b --(EO).sub.c --H;

o is an integer ranging from 1 to 100;

q is an integer ranging from 0 to 500;

EO is --(CH.sub.2 CH.sub.2 --O)--;

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

a is an integer ranging from 0 to 20;

b is an integer ranging from 0 to 20;

c is an integer ranging from 0 to 20.

5. A silicone polymer of claim 3 in which R.sup.2 is CH.sub.3 --CH(OH)--.

6. A silicone polymer of claim 3 wherein R.sup.2 is HO--CH.sub.2 --.

7. A silicon polymer of claim 4 in which R.sup.2 is

8. A silicone polymer of claim 4 wherein R.sup.2 is HO--CH.sub.2 --.