WO2005053633A1

WO2005053633A1 - Water in oil form cosmetic composition

Info

Publication number: WO2005053633A1
Application number: PCT/KR2004/002123
Authority: WO
Inventors: Jin-Hwang Kim; Seung-Ki Hong; Kee-Yeol Kyong; Moung-Seok Yoon
Original assignee: Lg Household & Health Care Ltd.
Priority date: 2003-12-03
Filing date: 2004-08-24
Publication date: 2005-06-16
Also published as: CN100421640C; KR100550967B1; KR20050053922A; CN1889921A

Abstract

The present invention relates to a water-in-oil cosmetic composition in the absence of an emulsifier, which offers long-term storage stability, causes no skin irritation and offers very good feeling when applied on skin by using a silica silylate instead of an emulsifier in the oil phase.

Description

WATER IN OIL FORM COSMETIC COMPOSITION

BACKGROUND OF THE INVENTION (a) Field of the Invention

The present invention relates to a water-in-oil cosmetic composition

having superior long-term storage stability, offering superior functionality when

applied on skin and causing little skin irritation. These effects are achieved

due to the stabilized dispersion of water drops by positioning silica silylate

particles at the interface of an inner phase of the water drops and an outer oil

phase. (b) Description of the Related Art

Generally, cosmetic compositions are emulsions of either the oil-in-

water type, in which a hydrophilic emulsifier is used, or the water-in-oil type, in

which a lipophilic emulsifier is used. Of the two types, the oil-in-water type is

preferred as cosmetic composition because the outer phase, or the water phase,

is light and offers a matte effect and superior emulsion stability. However, the

oil-in-water type has poor water resistance and tends to be sticky and take time

for absorption because a thickener has to be used to ensure long-term stability.

Moreover, the use of an emulsifier causes skin irritation.

On the other hand, the water-in-oil type can have a variety of

functionalities because the outer phase is an oil phase and the cosmetic effect

lasts for a long time because of improved water resistance. However, the

emulsion tends to be weighty and sticky because a wax or other additives are mixed in to the outer oil phase to ensure stability. Also, the long-term stability

is not good (European Patent No. 0770379).

Therefore, there have been efforts to solve the long-term stability

problem by using a silicone based emulsifier in the water-in-oil emulsion. To take a specific example, U.S. Patent No. 5,942,213 discloses a

method of preparing a water-in-oil emulsion, which is stable for as long as three

months in the temperature range of 4 °C to 45 °C, by adding a gelling agent, a

wax, etc. to a mixture of oil and water and increasing the content of silicone oil

up to 40 % using a silicone based emulsifier. This water-in-oil emulsion has

superior cosmetic consistency because the outer phase is oil. However,

because a silicone based emulsifier having an HLB (hydrophile-lipophile

balance) value of between about 2 and 6 is used, it gives a weighty feeling,

causes skin irritation and is not cleansed off well.

To solve this problem, research is being conducted on powders or

particles having amphiphilic surface which may be used to replace an emulsifier

to attain a long-term stability and skin safety of the emulsion (U.S. Patent Nos.

6585983, 6579529, 6410035, 6391321 and 6440399; Japan Patent Publication

Nos. 2000-095639 and 2000-095638).

The particles having an amphiphilic surface, employed in the above-

mentioned patents, are classified into surface-treated powders and composite

powders. Surface-treated powders refer to such inorganic particles as talc,

silica, titanium dioxide, zinc, etc. partially coated with a silicone polymer, so that hydroxyl groups and alkyl groups are present on the particle surface.

Composite powders refer to cross-linked polysiloxane particles, or the mother

particles, coated with inorganic oxide particles, so that alkyl groups are present

on the polysiloxane particles and hydroxyl groups are present on the inorganic

oxide particles. Although the surface-treated inorganic particles are

advantageous in controlling particle size and surface composition, the silicone

polymers coated on the surface may be peeled off easily. Also, because the

inorganic particles have a large specific gravity, stabilization of the emulsion is

very difficult. For the composite particles, it is impossible to reduce the particle

size, because the cross-linked polysiloxane particles are used as mother

particles. As a result, the resultant emulsion cannot be commercialized due to

lack of long-term stability.

SUMMARY OF THE INVENTION

It is an aspect of the present invention to provide a water-in-oil cosmetic

composition having as light a feeling and a matte appearance as that of oil-in-

water cosmetic compositions. The water-in-oil composition may have long-term

emulsion stability and be unharmful to skin in the absence of an emulsifier

which causes skin irritation,

DETAILED DESCRITPION OF THE PREFERRED EMBODIMENTS The present invention provides a water-in-oil cosmetic composition

comprising 5 to 90 parts by weight of an oil phase comprising silica silylate and

10 to 95 parts by weight of an aqueous phase. To be specific, the water-in-oil cosmetic composition comprises

(A) 5 to 90 parts by weight of an oil phase comprising (i) 5 to 90 parts by weight of an oil;

(ii) 0.001 to 10 parts by weight of a quaternary ammonium compound;

(iii) 0.001 to 10 parts by weight of an oil-soluble polymer; and (iv) 0.05 to 10 parts by weight of silica silylate; and

(B) 10 to 95 parts by weight of an aqueous phase comprising (i) 0.01 to 50 parts by weight of a moisturizer; (ii) 0.001 to 20 parts by weight of a low alcohol;

(iii) 0.001 to 10 parts by weight of an electrolyte; and (iv) 5 to 90 parts by weight of water. Preferably, the silica silylate has an average particle size of at most 500

nm and a surface silanol concentration ranging from 20 to 80 %. The water-in-oil composition has a structure of a water drop surrounded

by an oil, with the silica silylate present in the interface of the water drop and the

oil,

Preferably, the water drop has a size ranging from 0.1 to 100 μm. The present invention also provides a method of preparing a water-in-oil

cosmetic composition comprising the steps of

(a) mixing an oil, a quaternary ammonium compound, an oil-soluble polymer and silica silylate to prepare an oil phase; (b) mixing a moisturizer, water, a low alcohol and an electrolyte to prepare an aqueous phase; and

(c) adding the oil phase to the aqueous phase. Hereinafter, the present invention is described in more detail. Since the water-in-oil cosmetic composition of the present invention

comprises silica silylate instead of an emulsifier, it has a light feeling and

causes no optical irritation in anti-UV cosmetics. Also, because it can

comprise an oil phase up to 90%, it offers a superior consistency and a unique

skin feeling while capable of being easily cleansed off. The water-in-oil cosmetic composition of the present invention

comprises 5 to 90 parts by weight of an oil phase comprising silica silylate and

10 to 95 parts by weight of an aqueous phase comprising water-soluble

constituents. That is, in the water-in-oil cosmetic composition of the present

invention, a weight proportion of the oil phase [A] to the aqueous phase [B] ([A] /

[B]) ranges preferably from 0.05 to 9.0, more preferably from 0.1 to 3.0, to

provide superior long-term storage stability, skin safety and feeling. If the

proportion of the oil phase to the aqueous phase is below 0.05, a water-in-oil

emulsion may not be formed. Otherwise, if it is larger than 9.0, the water-in-oil

emulsion is separated. The silica silylate comprised in the oil phase is represented by the

general formula [SiO₂] and is prepared by substituting part of hydroxyl (-OH)

groups of the silanols (SiOH) present on the surface of hydrophilic silica with trimethylsiloxyl [-OSi(CH₃)₃] groups. Therefore, the silica silylate has both

hydrophilic hydroxyl groups (-OH) and lipophilic methyl groups (-CH₃), and thus

it has amphiphilic characteristics. This amphiphilicity may allow the silica

silylate to be present at the interface of oil and water, thereby stabilizing the

water drop. The degree of the hydrophilicity and the lipophilicity may be

different depending on the degree of substitution of the trimethylsiloxyl groups,

or the concentration of silanol on the surface of the silica silylate particle. As a

result, the water-in-oil cosmetic composition of the present invention may be

prepared into a stable emulsion without using an emulsifier. As the particle size of the silica silylate increases, the specific surface

area decreases. Thus, a lot of silica silylate is required to obtain an emulsion,

which worsens stability. Since more stable water-in-oil emulsion is obtained

when the particle size is smaller, it is preferable to use silica silylate particles

having an average diameter of at most 500 nm and a x silanol concentration at

the water-in-oil emulsion ranging from 20 to 80 %.

Preferably, the content of the silica silylate in the oil phase is within a

range from 0.05 to 10 parts by weight, more preferably 0.1 to 8 parts by weight,

per 100 parts by weight of the cosmetic composition. If the content of the silica

silylate is below 0.05 part by weight, it cannot function as emulsifier.

Otherwise, if it exceeds 10 parts by weight, it is difficult to prepare an emulsion

because of excess powders.

The oil phase also may include 5 to 90 parts by weight of an oil and may further comprise 0.001 to 10 parts by weight of a quaternary ammonium

compound and 0.001 to 10 parts by weight of an oil-soluble polymer to improve

feeling and stability of the cosmetic composition.

The oil is not particularly limited and may be at least one selected from

the group consisting of a plant oil, a mineral oil, a silicone oil and a synthetic oil,

which are conventionally used for this purpose.

The oil-soluble polymer may be any polymer known in the art. For

example, the oil-soluble polymer may include a phyto-polymer, a mineral

polymer, a silicone based polymer, a synthetic polymer and copolymers thereof

may be used.

For every 100 parts by weight of the cosmetic composition, the aqueous

phase include 0.01 to 50 parts by weight of a moisturizer to offer a moisturizing

effect, 0.001 to 50 parts by weight of a low alcohol to offer a freshening feeling,

0.001 to 10 parts by, weight of an electrolyte to improve stability and 5 to 90

parts by weight of water, per 100 parts by weight of the cosmetic composition.

The low alcohol is a Ci to C alcohol, preferably methanol, ethanol,

propanol, butanol or isopropanol, more preferably ethanol, which has been

shown to be safe for human.

The moisturizer may be any one that is conventionally used. For

example, the moisturizer is at least one compound selected from the group

consisting of glycerin, glycerol, sorbitol, propylene glycol and butylene glycol

may be used. The electrolyte may be any one known in the art. For example, the

electrolyte is at least one compound selected from the group consisting of

monovalent, divalent and trivalent compounds may be used.

The cosmetic composition of the present invention may further comprise

0.1 to 50 parts by weight of an organic UV protecting agent such as octyl

methoxycinnamate, octyl salicylate, octocrylene, butyl

methoxydibenzoylmethane, oxybenzone, octyl triazone, menthyl anthranilate,

3,4-methylbenzylidene camphor, etc., per 100 parts by weight of the cosmetic

composition, and 0.1 to 50 parts by weight of at least one inorganic metal UV

protecting agent selected from the group consisting of titanium dioxide, zinc

oxide, iron oxide, etc. in the oil phase, in order to block ultraviolet rays.

The cosmetic composition may further comprise common ingredients

mixed into general skin cosmetics, such as a low alcohol, a thickener, a

chelating agent, a pigment, an antiseptic, a perfume, etc., as required. The water-in-oil cosmetic composition of the present invention is

prepared by

(a) mixing an oil, a quaternary ammonium compound, an oil-soluble polymer and silica silylate to prepare an oil phase;

(b) mixing a moisturizer, water, a low alcohol and an electrolyte to prepare an aqueous phase; and

(c) adding the oil phase to the aqueous phase.

The water-in-oil emulsion prepared according to the present invention has a water drop size in a range from 0.1 to 100 μm, and thus it has superior

stability. The larger the size of water drop particles in an emulsion, the less

stable the emulsion is due to coagulation or consolidation. The water-in-oil

cosmetic composition of the present invention has a well-controlled particle size

due to the use of silica silylate. Therefore, the water-in-oil compositions

described herein have superior stability.

The cosmetic composition of the present invention is intended to be

used on skin. It may be prepared into common cosmetics, such as a

nourishing lotion, a nourishing cream, a massage cream, an essence, a pack, a

skin patch, a skin gel, a powder, an ointment, a suspension, an emulsion, a

spray, a lotion, etc. along with adequate conventional carriers or additives

known in the art. Also, the cosmetic composition may be prepared into skin-

contacting substances such as cosmetics, detergents, fibers, etc.

Hereinafter, the present invention is described in more detail through

examples. However, the following examples are only for the understanding of

the present invention and they do not limit the present invention.

EXAMPLES

An oil phase and an aqueous phase were prepared at a temperature

ranging from room temperature to 80 ^°C with the composition and content

shown in Table 1 below. The aqueous phase was slowly added to the oil

phase to prepare a water-in-oil emulsion. Then, the emulsion was cooled to 50 ^°C or lower and a perfume and an additive were added to prepare a water-in-

oil cosmetic composition.

The oil phase and aqueous phase of Examples and Comparative

Examples are as follows. (A) Oil phase

(i) Oil: Cyclomethicone, dimethicone, dimethicone polyol (ii) Quaternary ammonium compound: Distearatedimonium hectorite (iii) Oil-soluble polymer: Dimethicone/vinyldimethicone cross polymer (iv) Silica silylate: Average particle diameter = 500 nm or smaller, silanol concentration at the particle surface = 20 to 80 %

(v) Octyl hexanoate: Oil component (B) Aqueous phase (i) Low alcohol: Ethanol (ii) Electrolyte: Magnesium sulfate (iii) Moisturizer: Glycerin, propylene glycol, butylene glycol

Table 1

Uniformity and particle size of the water drop of the water-in-oil cosmetic

compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2

were compared with an optical microscope. The compositions were exposed to a temperature change of 50 ^°C to -15 ^°C for one to three months. The

separation status was evaluated to confirm the emulsion stability. The result is

shown in Table 2 below.

Table 2

As seen in Table 2, a water-in-oil cosmetic composition was not

prepared when neither silica silylate nor an emulsifier (dimethicone copolyol)

was used (Comparative Example 1 ). When the content of silica silylate was

0.1 wt% or lower, the particle size of water drop was very large and the

emulsion was unstable (Example 4). When the content of silica silylate was

0.1 wt% or over, a stable water-in-oil cosmetic composition was obtained, as

when an emulsifier was used (Comparative Example 2). <Testing Example 3: Feeling>

The cosmetic compositions prepared in Examples and Comparative

Examples were given to 50 women of ages ranging from 20 to 40 years old.

Feelings, such as lightness, sliminess, etc., cosmetic consistency and easiness

of cleansing were evaluated. Evaluation was performed by the following

standard: very superior = 5 points, superior = 3 points, moderate = 0 point, poor

= -3 points, very poor = -5 points. Rating was calculated by Equation 1 below.

The result is given in Table 3 below.

Equation 1

(N_vs x 5) + (N_s x 3) + (N,„ x 0) + [N x (-3)] + [N x (-5)] Rating N

where

N = Total number of subjects

N_vs - Number of subjects who evaluated as very superior

N_s = Number of subjects who evaluated as superior

N_m = Number of subjects who evaluated as moderate

N_p = Number of subjects who evaluated as poor

N_vp = Number of subjects who evaluated as very poor Table 3

As seen in Table 3, the cosmetic compositions prepared using silica

silylate (Examples 1 to 3) showed better feelings such as freshness, sliminess,

etc., cosmetic consistency and ease of cleaning compared with the cosmetic

composition prepared using a silicone based emulsifier (Comparative Example

2). Therefore, they offered better overall satisfaction. This seems to be due

to that fact that use of silica silylate improves sliminess and stickiness, which is

caused by an emulsifier. Ease of cleansing also seems to have been

improved in the absence of an emulsifier.

<Testing Example 4: Primary irritation test to human body (closed

patch)>

A human patch test was performed to confirm safety and irritation of the

cosmetic compositions prepared in Example 1 and Comparative Example 2.

The test was performed for 50 healthy adults (both men and women) according

to the CTFA guideline [Cf. The Cosmetic, Toility and Fragrance Association. Inc.

Washington, D.C., 20036, 1991]. 15 μL of each sample solution was added dropwise to a Finn chamber. Then, the solution was applied on the skin and

covered by a tape. The patch was removed 24 hours later. After 4 hours, the

status of the skin was evaluated by the following standard. The result is given

in Table 4 below.

(Evaluation standard)

- : No red spot or peculiarity

±: Slightly reddened

+: Significantly reddened

++: Significantly reddened and swollen

Equation 2

(N_± x l) + (N₊ x 2) + (N_+÷ x 3) Irritation index Number of subjects

Table 4

As seen in Table 4, the cosmetic composition not comprising an

emulsifier (Example 1 ) showed much less skin irritation than the one comprising

an (Comparative Example 2).

<Example 5 and Comparative Examples 3 and 4> An oil phase and an aqueous phase were prepared at 80 °C with the composition and content given in Table 5 below. A perfume and an additive

were added at a temperature of 50 ^°C or less to prepare a water-in-oil anti-UV

cosmetic composition (Example 5 and Comparative Example 3) and an oil-in-

water anti-UV cosmetic composition (Comparative Examples4). Example 5 and Comparative Example 3

(1 ) The oil phase and a UV protecting agent were mixed uniformly.

(2) The aqueous phase was mixed uniformly.

(3) The aqueous phase was slowly added to the oil phase while stirring

to obtain a water-in-oil emulsion. Comparative Example 4

(1 ) The oil phase and a UV protecting agent were mixed uniformly.

(2) The aqueous phase was mixed uniformly.

(3) The aqueous phase was slowly added to the oil phase while stirring

to obtain an oil-in-water emulsion.

Table 5

<Testing Example 5: Cosmetic consistency of anti-UV cosmetic

compositions> Each 100 mg of the water-in-oil cosmetic compositions of Example 5

and Comparative Example 3 and the oil-in-water anti-UV cosmetic composition

of Comparative Example 4 was applied on a vitroskin on an area of 50 cm².

After drying for 20 minutes, the vitroskin was moved back and forth repeatedly

in clean water for 40 minutes. Then, it was dried for 20 minutes. The

vitroskin was analyzed with a SPF290s analyzer. The in-vitro SPF analysis

result before and after immersion in water is given in Table 6 below.

Table 6

As seen in Table 6, the water-in-oil anti-UV cosmetic composition not

including an emulsifier (Example 5) maintained the in-vitro SPF value at over

90 % before and after immersion in water. The water-in-oil cosmetic

composition of Example 5 had a similar in-vitro SPF value when compared to

the water-in-oil anti-UV cosmetic composition including a silicone based

emulsifier. However, in the oil-in-water anti-UV cosmetic composition of

Comparative Example 4, the in-vitro SPF value after immersion in water

decreased to 40% of the in vitro SPF value before immersion. That is, the

water-in-oil anti-UV cosmetic composition prepared using silica silylate offers

better UV blocking consistency without being affected by water or sweat. As described above, because a stable water-in-oil cosmetic composition

can be prepared using silica silylate without using an emulsifier, a water-in-oil

cosmetic composition having superior lightness, mattness and cosmetic

consistency can be obtained. Also, the water-in-oil cosmetic composition of

the present invention causes no skin irritation.

While the present invention has been described in detail with reference

to the preferred embodiments, those skilled in the art will appreciate that various

modifications and substitutions can be made thereto without departing from the

spirit and scope of the present invention as set forth in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A water-in-oil cosmetic composition not comprising an emulsifier,

which comprises 5 to 90 parts by weight of an oil phase comprising silica

silylate and 10 to 95 parts by weight of an aqueous phase.

2. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 1 , which comprises 0.05 to 10 parts by weight of the silica silylate per 100

parts by weight of the cosmetic composition.

3. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 1 , wherein the silica silylate has an average particle size of at most 500

nm and a silanol concentration at the particle surface ranging from 20 to 80 %.

4. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 1 , wherein the oil phase further comprises 5 to 90 parts by weight of an oil,

0.001 to 10 parts by weight of a quaternary ammonium compound and 0.001 to

10 parts by weight of an oil-soluble polymer per 100 parts by weight of the oil

phase.

5. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 4, wherein the oil is at least one selected from the group consisting of a

plant oil, a mineral oil, a silicone oil and a synthetic oil.

6. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 4, wherein the oil-soluble polymer is at least one selected from the group

consisting of a phyto polymer, a mineral polymer, a silicone based polymer, a

synthetic polymer and copolymers thereof.

7. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 1 , wherein the aqueous phase comprises 0.01 to 50 parts by weight of a

moisturizer, 0.001 to 20 parts by weight of a low alcohol, 0.001 to 10 parts by

weight of an electrolyte and 5 to 90 parts by weight of water per 100 parts by

weight of the aqueous phase.

8. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 7, wherein the moisturizer is at least one selected from the group

consisting of glycerin, glycerol, sorbitol, propylene glycol and butylene glycol.

9. The water-in-oil cosmetic composition not comprising an emulsifier of

claim 7, wherein the low alcohol is ethanol.

10. The water-in-oil cosmetic composition not comprising an emulsifier

of claim 7, wherein the electrolyte is at least one selected from the group

consisting of a monovalent, divalent and trivalent compounds.

11. The water-in-oil cosmetic composition not comprising an emulsifier

of claim 1 , which further comprises an additive selected from the group

consisting of an organic UV protecting agent and an inorganic metal UV

protecting agent.

12. The water-in-oil cosmetic composition not comprising an emulsifier

of claim 11 , wherein the UV protecting agent is comprised in 0.1 to 50 parts by

weight and the inorganic metal UV protecting agent is comprised in 0.1 to 50

parts by weight per 100 parts by weight of the cosmetic composition.

13. The water-in-oil cosmetic composition not comprising an emulsifier according to any one of claims 11 and 12, wherein the organic UV protecting

agent is at least one selected from the group consisting of octyl

methoxycinnamate, octyl salicylate, octocrylene, butyl

methoxydibenzoylmethane, oxybenzone, octyl triazone, menthyl anthranilate

and 3,4-methylbenzylidene camphor.

14. The water-in-oil cosmetic composition not comprising an emulsifier

according to any one of claims 11 and 12, wherein the inorganic metal UV

protecting agent is at least one selected from the group consisting of titanium

dioxide, zinc oxide and iron oxide.

15. The water-in-oil cosmetic composition not comprising an emulsifier

of claim 1 , futher comprising a structure of a water drop surrounded by an oil,

wherein the silica silylate is present at the interface of the water drop and the oil.

16. The water-in-oil cosmetic composition not comprising an emulsifier

of claim 15, wherein the water drop has a size in a range from 0.1 to 100 μm.

17. A method of preparing a water-in-oil cosmetic composition not

comprising an emulsifier, which comprises the steps of

(a) mixing an oil, a quaternary ammonium compound, an oil-soluble

polymer and silica silylate to prepare an oil phase;

(b) mixing a moisturizer, water, a low alcohol and an electrolyte to

prepare an aqueous phase; and

(c) adding the aqueous phase to the oil phase.

18. A cosmetic composition comprising the water-in-oil cosmetic composition of claim 1.

19. The cosmetic composition not comprising an emulsifier of claim 18, which is at least one selected from the group consisting of a nourishing lotion, a nourishing cream, a massage cream, an essence, a pack, a skin patch, a skin

j gel, a powder, an ointment, a suspension, an emulsion and a spray.