JP2014065666A - Volatile oil for skin external preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a volatile oil for skin external preparation that is superior in volatility and skin care characteristics.SOLUTION: A volatile oil for skin external preparation comprises a paraffin mixture that comprises 12-16C isoparaffin, has the boiling point range of 185-215°C, and has the 2,2,4,6,6-pentamethylheptane content of less than 10 mass%.

Description

  The present invention is used for skin external preparations such as skin lotions, cleansing agents, emulsions, creams, ointments, packs, hair tonics, foundations, and other skin cosmetics and pharmaceuticals, and has excellent volatility and skin care properties. Relates to volatile oil.

  Conventional hydrocarbons that have been used as volatile oils include hydrocarbons having 6 to 12 carbon atoms such as n-hexane, isohexane, cyclohexane, n-octane, isooctane, n-nonane, and n-decane. And isododecane are known. However, since these volatile oils have a low flash point of 50 ° C. or lower, there is a problem that safety is poor. In addition, when these volatile oils are used in cosmetics and cleaning oils for the skin, there is a problem of high irritation to the skin and mucous membranes including the scalp, and moisture is easily evaporated from the surface of the living body due to high volatility. There's a problem.

  On the other hand, hydrocarbons having 15 or more carbon atoms such as n-pentadecane and isohexadecane are expected to improve performance such as an increase in flash point and a decrease in irritation to skin and mucous membranes due to their high molecular weight. Due to the decrease in volatility, the oil tends to remain and there is a problem that the feeling of use is inferior when applied to the skin.

  From such a background, as a volatile oil agent having excellent volatility, high flash point and safety for human body, for example, Patent Document 1 includes hydrocarbons having 12 to 14 carbon atoms and carbon atoms having 13 to 16 carbon atoms. It is disclosed that non-silicone compositions combining hydrocarbons and non-volatile hydrocarbons are used. In the field of cosmetics, for example, Patent Document 2 discloses that cyclic silicones such as cyclomethicone are used as volatile components (see paragraphs [0039] and [0040]).

Special table 2011-503192 gazette JP-A-6-157276

  However, in the method of Patent Document 1, 2,2,4,6,6-pentamethylheptane is contained in the non-silicone composition, so that the odor is strong and the skin becomes white when applied to the skin and feels dry. There is a problem that it is inferior to the feeling of use such as the occurrence of oil and is not preferable as an oil agent for external preparations for skin. On the other hand, although the method of Patent Document 2 is excellent in volatility, there is a concern that safety to the human body and the environment is concerned, and therefore there is a problem that use as an oil for external preparations on the skin is not preferable.

  Then, the objective of this invention is providing the volatile oil for skin external preparations which is excellent in volatility and skin care characteristics.

  The present inventors have found that the above-mentioned object can be achieved by setting the carbon number of the paraffin, the boiling range, 2, 2, 4, 6, 6-pentamethylheptane content in the specific range in the mixture of paraffins. .

That is, the present invention includes an isoparaffin having 12 to 16 carbon atoms, a boiling point range of 185 to 215 ° C., and a 2,2,4,6,6-pentamethylheptane content of less than 10% by mass. It is a volatile oil for external preparation for skin consisting of a mixture.
The skin external preparation in the present invention includes skin external preparations such as skin lotions, skin care products such as skin lotions, cleansing agents, emulsions, creams, ointments, packs, hair tonics and foundations. However, hair cosmetics are excluded from the external preparation for skin in the present invention. Hair cosmetics are cosmetics, cleaning products and pharmaceuticals for hair, such as aerosol hair spray, pump hair spray, foam hair spray, hair mist set lotion, hair styling, hair oil, shampoo, rinse, permanent liquid, Hair treatment.

  The volatile oil for external preparation for skin of the present invention has excellent volatility, high flash point, safety of operation, safety to human body and environment, and is excellent in various skin care characteristics when applied to the skin. Therefore, the volatile oil for external skin preparation of the present invention is useful as a raw material for external skin preparations such as cosmetics for skin, cleaning oils and pharmaceuticals. For example, it is useful as a substitute for cyclic silicones such as cyclopentasiloxane.

Hereinafter, embodiments of the present invention will be described.
The volatile oil for external skin preparation of the present invention comprises a mixture of paraffins (saturated hydrocarbons) containing isoparaffins (branched saturated hydrocarbons) having 12 to 16 carbon atoms, and is a straight chain having 12 to 16 carbon atoms. May contain chain saturated hydrocarbons. In addition, the volatile oil for external preparation for skin of the present invention includes hydrocarbons other than saturated hydrocarbons having 12 to 16 carbon atoms, such as cyclic saturated hydrocarbons and unsaturated hydrocarbons, to an extent not contrary to the object of the present invention. Etc. may be included.

  The paraffin mixture in the volatile oil for external preparation for skin of the present invention has a boiling range of 185 to 215 ° C, preferably 186 to 210 ° C. When the boiling point of the paraffin mixture is less than 185 ° C., the flash point becomes low, which is not preferable in terms of safety. When the boiling point exceeds 215 ° C., the volatility decreases and the oil tends to remain, so that the feeling of use when applied to the skin is inferior. The boiling point can be measured by a distillation test according to JIS K2254. In addition, the paraffin mixture in the present invention preferably has a flash point in the range of 61 to 70 ° C., particularly 62 to 67 ° C. in the sealing test according to JIS K2265, in terms of safety and odor. For example, commercially available isododecane (2,2,4,6,6-pentamethylheptane content of 95% by mass or more) has a boiling point as low as 177 ° C. and a flash point of about 48 ° C., so care must be taken when handling fire. And strong odor. On the other hand, when the flash point exceeds 70 ° C., the drying property is deteriorated and the feel may be heavy.

  In the paraffin mixture of the present invention, the content of 2, 2, 4, 6, 6-pentamethylheptane (hereinafter also referred to as isododecane) is less than 10% by mass, preferably less than 8% by mass, and more preferably Is less than 5% by weight. If the content of isododecane in the mixture is 10% by mass or more, the boiling point is lowered, which is not preferable in terms of safety, and the odor becomes strong and the feeling of use on the skin is reduced, so that the use as a raw material for cosmetics is restricted. Is done.

The paraffin mixture in this invention can be manufactured through the process containing the following processes 1-4, for example.
Step 1) A step of removing a non-reacted component and a polymer having 20 or more carbon atoms from a polymerization reaction system of isobutylene and normal butene to obtain a polybutene mixture having 16 or less carbon atoms.
Step 2) A step of hydrogenating the polybutene mixture having 16 or less carbon atoms obtained in Step 1 to obtain a paraffin mixture having 16 or less carbon atoms.
Step 3) A step of adsorbing the paraffin mixture having 16 or less carbon atoms obtained in Step 2 with an adsorbent to bring the iron content to 10 ppm or less.
Step 4) A step of distilling the paraffin mixture having 16 or less carbon atoms adsorbed in Step 3 under reduced pressure to distill off 15% by mass or more based on the charged amount.

The steps 1 to 4 will be described sequentially.
First, the polymerization reaction system of isobutylene and normal butene used in Step 1 uses a known method, for example, a catalyst, using a mixed gas of isobutylene and normal butene which is a C4 fraction in the fraction obtained by cracking of naphtha. It can be obtained by the conventional cationic polymerization method. Therefore, the polymerization reaction system of isobutylene and normal butene includes a polybutene mixture (a copolymer of isobutylene and normal butene, an isobutylene (co) polymer, and a normal butene polymer). A mixture of saturated hydrocarbons), unreacted components (such as isobutylene and normal butene contained in the mixed gas), and a catalyst.

  In normal butene, there are isomers of 1-butene, cis-2-butene and trans-2-butene. The mixed gas composition for obtaining a copolymer of isobutylene and normal butene is 15 to 80% by mass of isobutylene, 10 to 40% by mass of 1-butene and 10 in total of cis-2-butene and trans-2-butene. It is preferably ˜60% by mass, more preferably 15 to 70% by mass of isobutylene, 15 to 40% by mass of 1-butene, and 15 to 60% by mass in total of cis-2-butene and trans-2-butene. Particularly preferably 15 to 60% by weight of isobutylene, 15 to 40% by weight of 1-butene and 15 to 40% by weight in total of cis-2-butene and trans-2-butene, Preferably, isobutylene is 20 to 50% by mass, 1-butene is 18 to 25% by mass, cis-2-butene and trans-2- 10 to 40% by mass in total, more preferably 20 to 33% by mass of isobutylene, 18 to 25% by mass of 1-butene and 18 to 25 in total of cis-2-butene and trans-2-butene % By mass. The mixed gas may contain components that do not contribute to the copolymerization reaction, such as isobutane and butane.

  Examples of the catalyst used in the cationic polymerization method include aluminum chloride, acidic ion exchange resin, sulfuric acid, boron fluoride, and complexes thereof. It is also possible to control the polymerization reaction by adding a base to the catalyst. The polymerization reaction is usually performed at 40 to 120 ° C.

  As described above, the polymerization reaction system of isobutylene and normal butene contains a polybutene mixture which is a polymerization reaction product of isobutylene and normal butene, an unreacted component, and the like. In step 1, unreacted components and a polymer having 20 or more carbon atoms are removed from the polymerization reaction system to obtain a polybutene mixture having 16 or less carbon atoms. As the removal method, distillation is preferred. Examples of the distillation method include a simple distillation method, a continuous distillation method, a steam distillation method, and a thin film distillation method, and these methods can be performed alone or in combination. The apparatus used for distillation is not particularly limited in terms of the material, shape, type, and the like, and examples thereof include a distillation column filled with a packing such as Raschig ring, a plate distillation column having a dish-like shelf, and the like. The number of theoretical plates showing the separation ability of the distillation column is preferably 10 or more. In addition, the conditions for the feed amount to the distillation column, the reflux ratio, and the removal amount can be appropriately selected depending on the distillation apparatus.

  In Step 2, the polybutene mixture having 16 or less carbon atoms obtained in Step 1 is hydrogenated to obtain a polybutene hydride, that is, a mixture of 16 or less carbon atoms containing isoparaffin. The polybutene having 16 or less carbon atoms obtained in Step 1 leaves a double bond at the polymerization terminal, and therefore causes deterioration such as coloring when stored for a long period of time. In order to solve this, a hydrogenation reaction is performed in step 2 to obtain a hydrogenated product. The hydrogenation reaction can be performed, for example, using nickel, palladium, or the like as a hydrogenation catalyst at a temperature of 180 to 230 ° C., and contacting hydrogen at a pressure of 2 to 10 MPa. The degree of hydrogenation for obtaining the paraffin mixture in the present invention is preferably 10 or less in terms of iodine value. A more preferred degree of hydrogenation is 1 or less in terms of iodine value, and a further preferred degree of hydrogenation is 0.1 or less in terms of iodine value. When the iodine value exceeds 10, oxidation by heat and light tends to proceed, and odor is likely to be generated.

  The paraffin mixture having 16 or less carbon atoms obtained in step 2 includes trace metal compounds contained in the catalyst used in the hydrogenation reaction, iron content generated by corrosion of the reactor due to the high acidity of the catalyst, etc. Trace metals may be mixed. These trace metals adversely affect the odor and storage stability of the paraffin mixture. Among trace metals, especially the iron content is a cause of an unpleasant odor due to the further worsening of the odor in the reaction in the subsequent distillation operation for obtaining the paraffin mixture in the present invention. Therefore, for the purpose of suppressing coloring and odor, in Step 3, a paraffin mixture having 16 or less carbon atoms is adsorbed with an adsorbent.

  As the adsorbent, inorganic and organic adsorbents are used. For example, clay, kaolin, talc, calcium carbonate, diatomaceous earth, zeolite, bentonite, acid clay, activated clay, vermiculite, silica gel, molecular sieve, and activated carbon are used. In particular, activated clay and clay are effective. These adsorbents can be used alone or in combination of two or more. The adsorbent is effective not only for physically removing trace metals and iron components derived from the hydrogenation reaction catalyst, but also for removing trace decomposition and by-product low-molecular oxides caused by high temperatures in hydrogenation, This is more effective for maintaining the stability of the product after distillation. The particle size of the adsorbent to be used is not particularly limited. However, when one kind of adsorbent is used, it is preferable to combine two or more adsorbents having different particle sizes. The combination of adsorbents is appropriately selected according to the dispersion of pressure in the column packed with the adsorbent and efficient processing. When two or more kinds of adsorbents are used, it is more effective in terms of production to pack 50 to 80% by volume of the smallest particle size with respect to the column volume.

  The paraffin mixture adsorbed in step 3 contains isododecane with a low flash point and an unpleasant odor. Therefore, in step 4, the paraffin mixture having 16 or less carbon atoms adsorbed in step 3 is distilled under reduced pressure, and 15% by mass or more, preferably 25% by mass or more with respect to the charged amount before performing this vacuum distillation. Distill off. In addition, from a viewpoint of suppressing the fall of the flash point of a paraffin mixture, 40 mass% or less is preferable with respect to the preparation amount before performing vacuum distillation, and 35 mass% or less is more preferable.

For distillation in vacuum distillation, the distillation method and distillation apparatus described in Step 1 above can be employed. The distillation conditions are such that the liquid temperature in the container is 50 to 180 ° C., preferably 100 to 180 ° C., and the internal pressure of the container is 0.5 to 80 kPa, preferably 5 to 80 kPa. By the distillation step of this step, isododecane and other low-boiling substances (such as saturated hydrocarbons having 8 carbon atoms) contained in the paraffin mixture can be distilled off.
Through the steps including the above steps 1 to 4, a paraffin mixture containing isoparaffin having 12 to 16 carbon atoms can be produced.

  The volatile oil for skin external preparation of the present invention comprising the above paraffin mixture can be used as a solid and liquid base material used for skin external preparations such as cosmetics, cleansing oils and pharmaceuticals for the skin.

  When the volatile oil for external preparation for skin of the present invention is used for the external preparation for skin, the content of the volatile oil for external preparation for skin can be appropriately selected. In particular, when the effect of the volatile oil for external preparation of the present invention can be remarkably expressed, for example, when improving the volatility or improving the dilutability and compatibility of other cosmetic base materials, Although the blending amount varies depending on the purpose of use, the volatile oil for external preparation for skin of the present invention is used in 3 to 90% by mass, preferably 10 to 70% by mass for external preparation for skin (cosmetics for skin, cleansing oils, pharmaceuticals, etc.) % Blended.

  Skin external preparations (cosmetics for skin, cleansing oils, pharmaceuticals, etc.) containing the volatile oil for external preparations of the present invention include auxiliaries and additives such as surfactants, further oil components, Moisturizer, pearlescent wax, thickener, thickener, overfat, stabilizer, water-soluble and oil-soluble polymer, fat, wax, lecithin, phospholipid, biogenic active substance, UV absorber, UV scattering agent , Organic and inorganic pigments, antioxidants, deodorants, whitening agents, antiperspirants, analgesic and anti-inflammatory agents, blood circulation promoters, film formers, swelling agents, insect repellents, antiseptics, tyrosinase inhibitors (depigmenting agents) ), Hydrotropes, solubilizers, preservatives, perfume oils, colorants, pH adjusters, chelating agents can also be added.

Skin external preparations (cosmetics for skin, cleansing oils, pharmaceuticals, etc.) containing the volatile oil for external skin preparation of the present invention can be applied to various dosage forms, for example, liquid, cream, emulsion Skin lotion, skin cream, cleansing oil, cleansing cream, cleansing foam, cleansing gel, cleansing lotion, cleansing mask, essence, beauty cream etc., ointment Useful as a spray.
Such an external preparation for skin can also be produced by emulsification or mixing, for example, using a stirrer such as a homogenizer, a homomixer or a mill, or using a stirrer applying other principles such as high pressure or ultrasonic waves. Emulsification and mixing can be performed.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Various physical property values in each example were measured by the following methods.

<Iodine number>
It conforms to the iodine value test method of JIS K0070.
<Boiling range>
It conforms to the distillation test method of JIS K2254.
<Flash point>
Conforms to the closed flash point measurement method of JIS K2265.

<Number average molecular weight>
The number average molecular weight (polystyrene conversion) was measured using a Shimadzu GPC (gel permeation chromatography) measuring device.

<Method for analyzing isododecane content>
Using isododecane as a sample, the elution position was confirmed by GC-14B gas chromatography analysis made by Shimadzu, and the content of the compound corresponding to the elution position was measured.
Gas chromatography analysis conditions Column: Nonpolar capillary column, 0.55 mm, 30 m, 5 μm
Temperature: 80 ° C-250 ° C, temperature rise analysis at 10 ° C / min

[Example 1]
The volatile oil for skin external preparation which consists of a paraffin mixture was manufactured through the following processes 1-4.
360 g of a mixed gas composed of 30% by mass of isobutylene, 18% by mass of 1-butene and 25% by mass of 2-butene and a mixed gas of 4 carbon atoms and the remaining 27% by mass of butane gas are charged into an autoclave. The polymerization reaction was carried out in the presence to obtain a polymerization reaction system of isobutylene and normal butene.

(Process 1)
After the reaction, the unreacted gas in the autoclave was removed by nitrogen gas replacement, and then the polybutene mixture as the polymerization reaction mixture was extracted. The catalyst was removed by a caustic aqueous solution treatment and a water washing step. Next, the polybutene mixture after water washing is charged into a 1 L four-necked flask, heated by an oil bath, and after removing unreacted gas components dissolved in the polybutene mixture by nitrogen bubbling at an internal temperature of 40 ° C., Simple distillation was performed at an internal temperature of 140 ° C. and a degree of vacuum of 5 kPa. As a result, a polymer having 20 or more carbon atoms was left as a distillation residue in the flask, and a polybutene mixture having 16 or less carbon atoms was obtained. This polybutene mixture had a number average molecular weight of about 185.

(Process 2)
This polybutene mixture was hydrogenated in an autoclave with a hydrogenation catalyst (0.5% Pd-supported alumina catalyst) 10% by mass at a hydrogen pressure of 3 MPa and 220 ° C. to obtain 160 g of a paraffin mixture. The paraffin mixture had an iodine number of 0.1 and a number average molecular weight of about 180.

(Process 3)
A glass cylinder having an outer diameter of 4 cm and a length of 30 cm was filled with attapulgus clay and activated clay in a volume ratio of 50:50 in advance, and then filled with activated clay, and then an adsorption column was obtained. The paraffin mixture obtained in step 2 was continuously fed from the lower part of the adsorption column at a flow rate of 1 ml at a flow rate of 25 ° C. to perform adsorption treatment of trace metal compounds derived from the catalyst and from the apparatus material.

(Process 4)
150 g of the paraffin mixture after the adsorption treatment obtained in Step 3 is charged in the bottom container of the 15-stage Older Show shelf rectification column, put in an oil bath, and dried nitrogen gas until the liquid temperature in the container reaches 110 ° C. Bubbling was performed to avoid contact with air. When the liquid temperature in the container reached 110 ° C., vacuum distillation was performed for 8 hours under reduced pressure (10 kPa) with a reflux ratio of 10 and a distillation outflow temperature of 95 ° C. to distill off 25% by mass of the total amount charged. Thereafter, dry nitrogen gas was bubbled again under reduced pressure to cool the liquid in the bottom container to obtain 112.5 g of a paraffin mixture. The 2, 2, 4, 6, 6-pentamethylheptane (isododecane) content in the paraffin mixture was 2% by mass.

[Example 2]
In Step 4, except that 18% of the total amount charged was distilled off, the same operation as in Example 1 was performed to obtain 123 g of a volatile oil for external preparation for skin comprising a paraffin mixture. The content of 2, 2, 4, 6, 6-pentamethylheptane (isododecane) in this paraffin mixture was 8% by mass. Moreover, the boiling range of this paraffin mixture was 185.0-212.1 degreeC.

  The boiling point, volatility of the volatile oil for external preparation for skin comprising the paraffin mixture obtained in Example 1, the feeling of use when applied to the skin, compared with various conventional external preparation oils having volatility, The results are summarized in Table 1.

  In addition, the volatility order in Table 1 was obtained by spreading 0.1 g of a sample on a filter paper having a diameter of 110 mm and measuring the mass of drying for 2 hours. The order was given in order from the fastest speed of complete drying and mass of 0 g.

  The feeling of application on the skin was sensory evaluated by 10 panelists.

(Note 1) “Marcazole R” manufactured by Maruzen Petrochemical Co., Ltd.
[12 carbon atoms, flash point 48 ° C., isododecane content 95 mass% or more]
(Note 2) “SH-245” manufactured by Toray Dow Corning Co., Ltd. [flash point 77 ° C.]
(Note 3) Made by NOF Corporation, hydrogenated polybutene: Pearl Ream 4
[16 carbon atoms, boiling range 220-252.5 ° C., flash point 88 ° C., isododecane content 0 mass%]

  As shown in Table 1, the volatile oil for skin external preparation of the present invention according to Example 1 is not only superior in volatility than the cyclic silicone, but also excellent in the feeling of use of the oil alone. Was also confirmed to be good. Next, the result of having evaluated the various characteristics with respect to the skin as volatile oil for external preparations for skin is shown.

  Using the volatile oil for external preparation for skin made of a paraffin mixture produced in Examples 1 and 2, comparative evaluation with blanks without oil treatment having various characteristics shown below was performed. As a comparative example, Table 2 also shows the results of a similar evaluation of cyclic silicone oil, isododecane and hydrogenated polyisobutene.

[Slip evaluation]
Using the volatile oil for external preparation for skin of the present invention, the coefficient of friction was measured by the following method to evaluate the improvement of the slipperiness at the time of skin application.
Slip evaluation (improvement effect after treatment of each sample on skin) Method (evaluation) MIU (resistance value: μ): Friction resistance of skin surface (measuring device) Use of friction tester (manufactured by Kato Tech Co., Ltd.) (measuring conditions) ) Measurement environment 20 ° C., humidity 40%, constant temperature and humidity chamber, measurement site: upper arm inner side, contactor: silicon rubber, load amount: 25 gf
(Various oil application and test preparation)
(1) The subject's measurement site is washed with a neutral detergent and tap water and dried. A subject enters a constant temperature and humidity room 30 minutes before the measurement, and adjusts the measurement site to the indoor environment.
(2) Measure the coefficient of friction at the site of application before applying the sample.
(3) Use a micropipette to drop 10 μL of the sample onto the measurement site, and use a finger to extend a region approximately 1.5 cm wide and approximately 5 cm long from the elbow to the wrist. Wipe off the excess sample with a paper cloth (trade name: Kimwipe).
(4) After applying the sample, measure the coefficient of friction at the application site every 30 minutes.
(Determination) The sliding property after each sample treatment was evaluated with the coefficient of friction of the measurement site before the oil treatment as 100%. If there is an improvement effect on the untreated oil (blank), the value is lower than 100%.

[Moisture retention evaluation]
Using the volatile oil for external preparation for skin of the present invention, the amount of water in the stratum corneum was measured by the following method to evaluate the amount of water (moisture retention).
(Measurement device) SKICON-200EX (IBS)
(Measurement conditions) Temperature 20 ° C, humidity 40%
(Test method) A sample is applied to the inner side of a human forearm, and the water content after 2 hours is measured.
(Various oil application and test preparation)
(1) The subject's measurement site is washed with a neutral detergent and tap water and dried. A subject enters a constant temperature and humidity room 30 minutes before the measurement, and adjusts the measurement site to the indoor environment.
(2) Measure the amount of water at the site of application marked in a 1 cm diameter circle before applying the sample.
(3) Drop 10 μL of the sample with a micropipette on the measurement site marked in a circle with a diameter of 1 cm, and apply it to the skin on the marking site.
(4) Measure the moisture content at the measurement site 2 hours after application.
(Determination) The water content after each sample treatment was evaluated with the water content of the untreated oil (blank) at the measurement site as 100%. If there is an improvement effect on the blank, the value is higher than 100%.

[Evaluation of barrier properties]
Using the volatile oil for external preparation for skin according to the present invention, the amount of water transpiration in the stratum corneum was measured by the following method to evaluate the amount of transpiration (barrier property).
(Measurement device) Tewameter TM210 (Courage + Kahazaka)
(Measurement conditions) Temperature 20 ° C, humidity 40%
(Test method) A sample is applied to the inner side of a human forearm, and the amount of water transpiration after 2 hours is measured.
(Various oil application and test preparation)
(1) The subject's measurement site is washed with a neutral detergent and tap water and dried. A subject enters a constant temperature and humidity room 30 minutes before the measurement, and adjusts the measurement site to the indoor environment.
(2) Measure the amount of water transpiration at the site of application marked in a 1 cm diameter circle before sample application.
(3) Drop 10 μL of the sample with a micropipette on the measurement site marked in a circle with a diameter of 1 cm, and apply it to the skin on the marking site.
(4) Measure the amount of water transpiration at the measurement site 2 hours after application.
(Determination) The amount of water transpiration after the treatment of each sample was evaluated with the amount of water transpiration of the untreated (blank) of the measurement site as 100%. If there is an improvement effect on the blank, the value is lower than 100%.

(Skin viscoelasticity evaluation)
Using the volatile oil for external preparation for skin of the present invention, the viscoelasticity of the skin was measured by the following method to evaluate the skin viscoelasticity.
(Measurement device) Cutometer (made by IBS)
(Measurement conditions) Temperature 20 ° C, humidity 40%
(Test method) A sample is applied to the inner side of a human forearm, and viscoelasticity after 2 hours is measured.
(Various oil application and test preparation)
(1) The subject's measurement site is washed with a neutral detergent and tap water and dried. A subject enters a constant temperature and humidity room 30 minutes before the measurement, and adjusts the measurement site to the indoor environment.
(2) Measure the viscoelasticity of the site to be coated marked in a 1 cm diameter circle before applying the sample.
(3) Drop 10 μL of the sample with a micropipette on the measurement site marked in a circle with a diameter of 1 cm, and apply it to the skin on the marking site.
(4) The viscoelasticity of the measurement site 2 hours after application is measured.
(Determination) The skin viscoelasticity after the treatment of each sample was evaluated with the moisture content of the untreated oil (blank) at the measurement site as 100%. If there is an improvement effect on the blank, the value is higher than 100%.

(Note 1) “SH-245” manufactured by Toray Dow Corning Co., Ltd. [flash point 77 ° C.]
(Note 2) “Marcazole R” manufactured by Maruzen Petrochemical Co., Ltd.
[12 carbon atoms, flash point 48 ° C., isododecane content 95 mass% or more]
(Note 3) Made by NOF Corporation, hydrogenated polybutene: Pearl Ream 4
[16 carbon atoms, boiling range 220-252.5 ° C., flash point 88 ° C., isododecane content 0 mass%]

  The volatile oil for external preparation for skin of the present invention is not only excellent in volatility and the feeling of use when applied to the skin, but from the evaluation results shown in Table 2, it is more slippery than various conventional external preparation oils, It is clear that the skin care properties of moisture retention, barrier properties and skin viscoelasticity are also excellent. Therefore, the skin external preparation excellent in these effects is obtained by mix | blending the volatile oil for skin external preparations of this invention with a skin external preparation.

Claims (1)

  Skin external use comprising an isoparaffin having 12 to 16 carbon atoms, a boiling range of 185 to 215 ° C., and a paraffin mixture having a content of 2,2,4,6,6-pentamethylheptane of less than 10% by mass Volatile oil.