JPH0579045B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an oil-in-water (hereinafter referred to as O/W) emulsion composition, more specifically, an oil-in-water type (hereinafter referred to as O/W) emulsion composition, which has excellent storage stability and skin safety over a wide temperature range. The present invention relates to an O/W makeup cosmetic having the following.

[Prior Art] Generally, separation of makeup cosmetics occurs by creaming (or precipitation), agglomeration, or coalescence of emulsified particles. At high temperatures, water droplets tend to coagulate, resulting in a syneresis phenomenon, that is, the water phase, which is a continuous layer, tends to separate into the lower layer.As the water droplets coalesce, the particle size increases, and as a result, the water droplets settle and form the upper layer. part is only an oil phase, and separation of the oil phase is likely to occur. If the coalescence proceeds further, separation of the aqueous phase will occur.
In particular, relatively stable O/W emulsion compositions can be obtained with non-polar oils such as paraffin oil, but with polar oils such as olive oil, even the stability at room temperature is not satisfactory.

Particularly in the case of cosmetics containing various pigments such as make-up cosmetics, it is difficult to ensure not only emulsion stability but also pigment dispersion stability.

Conventionally, emulsified compositions have generally been emulsified using surfactants. Surfactants are a group of substances that have a hydrophilic group and a lipophilic group in one molecule and exhibit surfactant ability, and have high solubility in base materials and strong permeability into the skin. Therefore, it may cause skin irritation in some people.

[Problems to be Solved by the Invention] In view of the above circumstances, the present inventors have conducted intensive research with the aim of obtaining O/W makeup cosmetics that have excellent storage stability and good safety, and as a result, have identified The present inventors have discovered that the above object can be achieved by using a fine particle-sized organic polymer powder as an emulsifier without the need for the combined use of conventionally used surfactants, leading to the completion of the present invention.

[Means for Solving the Problems] That is, the present invention is an oil-in-water makeup cosmetic containing a polymethacrylic acid alkyl ester having an average particle size of 0.01 μm to 1 μm.

The present invention differs from the conventional concept of dissolving a surfactant in a base to emulsify an oil phase and an aqueous phase.
It is based on a completely new concept of emulsifying an oil phase and an aqueous phase by directly dispersing a solid with emulsifying ability in a base.

This emulsification method is not affected by the polarity of the oil phase, and does not require the conventional complicated procedure of selecting surfactants based on the HLB (hydrophilic/lipophilic) balance. Furthermore, since the organic polymer fine powder is a substance that does not dissolve in either the water phase or the oil phase, the balance of the system is less likely to be disrupted even when various pigments are added, and pigment aggregation is less likely to occur.
Furthermore, it has good safety against the skin, etc., and is compatible with polyoxyethylene (hereinafter referred to as
POE) sorbitan fatty acid ester or POE
It is clearly superior to hydrophilic surfactants such as alkyl ethers.

The configuration of the present invention will be described below.

Polymethacrylic acid alkyl esters used in the present invention include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, octyl methacrylate, decyl methacrylate, nonyl phenyl methacrylate, benzyl methacrylate, Examples include cyclopentenyl methacrylate, isobornyl methacrylate, etc. Polymethyl methacrylate is particularly easy to make into fine powder, the powder itself is spherical and transparent, has almost no odor, is safe, and is suitable for O/W makeup. It has excellent emulsifying ability.

The average particle size of the polymethacrylic acid alkyl ester is 0.01 μm to 1 μm, preferably
It is 0.2 μm to 0.5 μm. Particle size is less than 0.01μm
If it exceeds 1 μm, it is difficult to obtain a stable emulsion.

The organic polymer fine powder may be produced by a conventionally known method. One production example is shown below using polymethyl methacrylate as an example.

A monomer of methyl methacrylate is emulsion polymerized in the presence of another monomer that can be emulsion copolymerized with it, such as methacrylic acid, a metal salt is added as necessary to prepare an emulsion of polymer particles, and a polymer is produced from this emulsion. Collect and dry the particles,
Thereafter, this is crushed in a jet mill and classified.

The amount of polymethacrylic acid alkyl ester is 0.1% to 10% by weight based on the total amount of O/W emulsion composition,
Preferably it is 0.5% to 5% by weight. If the blending amount is less than 0.1% by weight, it may be difficult to stabilize O/W makeup cosmetics, and 10% by weight.
If it exceeds 20%, the viscosity tends to increase, making it difficult to manufacture.

As the oil used in the O/W makeup cosmetic of the present invention, oils generally used in foods, paints, medicines, cosmetics, etc. can be used, and examples include paraffin oil, squalane, paraffin wax, ceresin, etc. hydrocarbons, natural animal and vegetable oils and fats such as olive oil, camellia oil, soybean oil, macadamia nut oil, castor oil, lanolin, carnauba wax, yellowtail wax, spermaceti wax, beeswax, jojoba oil, waxes, fatty acids with 10 to 35 carbon atoms, carbon atoms 10 or more
35 alcohol, synthesized esters having 16 or more carbon atoms, such as isopropyl myristate, isostearate diglyceride, 2-ethylhexanoate triglyceride, diisostearyl malate,
Myristyl myristate etc.

Any one kind or two or more kinds of these oils can be used, and the blending amount is generally 20% by weight to 80% by weight.

In addition to the above-mentioned essential ingredients of polymethacrylic acid alkyl ester, oil, and water, the O/W makeup cosmetic of the present invention may optionally contain other surfactants, humectants, dyes, pigments, ultraviolet absorbers, fragrances, and medicinal ingredients. agent,
Preservatives, antioxidants, etc. can be added as appropriate.

[Examples] In order to further understand the present invention, Examples and Comparative Examples are listed below. All parts in the examples are expressed by weight.

Example 1 Cream foundation Purified water 36.8 Propylene glycol 3 Glycerin 2 Methyl paraoxybenzoate 0.1 Methyl methacrylate/methacrylic acid copolymer (average particle size 0.3 μm) 3 Kaolin 5 Talc 10 Titanium oxide 2 Red iron oxide 0.2 Yellow iron oxide 0.8 Fragrance 0.1 Manufacturing method Dissolve ~ uniformly at 80℃, add ~ to disperse, and further add ~ to emulsify. The mixture was cooled while stirring to obtain an O/W cream foundation.

The O/W cream foundation produced in this example had good iron oxide dispersibility during production,
Furthermore, even when stored for 3 months under temperature conditions of 0°C, room temperature, and 37°C, the product remained stable without separation of oil and water.

It also had an excellent creamy feel and caused less makeup smearing.

Comparative Example 1 Comparative Example 2 was obtained in the same manner as in Example 1 except that the methyl methacrylate/methacrylic acid copolymer in Example 1 was replaced with 3 parts of POE (30 mol) oleyl ether.

The emulsion type of the prepared sample was confirmed by electrical conductivity, and the emulsion particle size was observed using a microscope. The samples were stored at each temperature for 15 days, and their stability was examined based on the state of separation and changes in particle size.

In Comparative Example 1, although emulsification was achieved, iron oxide and titanium oxide were agglomerated and the original color tone could not be obtained.Also, although stirring was continued for 1 hour, the aggregation of iron oxide and titanium oxide further progressed. Eventually everything settled down.

In contrast, Example 1 had good emulsion stability and dispersion stability, and was an O/W emulsion cosmetic that was stable for 3 months or more even when left at 37°C, room temperature, and 0°C.

[Effects of the Invention] The O/W emulsion composition according to the present invention has extremely good storage stability (emulsion stability and dispersion stability) over a wide temperature range compared to conventional compositions. It is also an emulsified composition with extremely high safety in terms of skin irritation. Therefore, O/W in various fields
It is an emulsifying composition that can be applied as an emulsifying composition and is particularly useful in the field of cosmetics.

Claims (1)

[Claims] 1. An oil-in-water makeup cosmetic comprising polymethacrylic acid alkyl ester having an average particle size of 0.01 μm to 1 μm.