Oily moisturizer and topical skin composition containing same

Abstract

This oily moisturizer is composed of either an esterified product of a component A that is ditrimethylolpropane, and a component B that is one fatty acid, or two or more fatty acids, selected from among saturated fatty acids of 6 to 12 carbon atoms, or an esterified product of the component A, the component B, and a component C that is one fatty acid, or two or more fatty acids, selected from among fatty acids of 13 to 28 carbon atoms, wherein the hydroxyl value of the esterified product is not more than 140 mgKOH/g, and the mass ratio between fatty acid residues derived from the component B and fatty acid residues derived from the component C within the fatty acid residues that constitute the esterified product of the component A, the component B and the component C is within a range from 99.9:0.1 to 60:40.

Claims

1. An oily moisturizer comprising an esterified product of a component A and a component B1, wherein a hydroxyl value of the esterified product is less than 10 mgKOH/g, the component A is ditrimethylolpropane, and the component B1 is capric acid, or a mixture of capric acid and caprylic acid.

2. The oily moisturizer of according to claim 1, wherein the hydroxyl value of the esterified product is not more than 3 mgKOH/g.

3. The oily moisturizer according to claim 1, wherein the oily moisturizer comprises the esterified product of the component A and the component B1, and the esterified product includes a tetraester of the component A and the component B1.

4. The oily moisturizer according to claim 1, wherein the component B1 is a mixture of caprylic acid and capric acid.

5. A topical skin composition comprising the oily moisturizer according to claim 1.

6. The topical skin composition according to claim 5, wherein the topical skin composition is a cosmetic, a face wash, a full body cleanser, or a topical pharmaceutical.

7. A moisture retention method for skin, comprising applying a topical skin composition comprising the oily moisturizer according to claim 1 to a skin surface.

8. A method of retaining moisture of a surface, comprising applying the oily moisturizer according to claim 1 to the surface.

9. A method for producing the oily moisturizer according to claim 1, the method comprising: mixing the esterified product of the component A and the component B1 with an additional component, wherein the additional component is selected from the group consisting of a cosmetic component, a cleanser component, and a topical pharmaceutical component.

10. The method for producing the oily moisturizer according to claim 9, wherein the oily moisturizer is a moisturizing cosmetic, a face wash, or a fully body cleanser.

11. A topical skin composition comprising the oily moisturizer according to claim 2.

12. The topical skin composition according to claim 11, wherein the topical skin composition is a cosmetic, a face wash, a full body cleanser, or a topical pharmaceutical.

Description

EXAMPLES

(1) The present invention is described below in further detail based on a series of examples, but the present invention is in no way limited by these examples. In the following description, unless specifically stated otherwise, “%” means “% by mass”.

[Example 2] Production of Esterified Product

(2) Using ditrimethylolpropane and caprylic acid as reaction raw materials, an esterification reaction was performed with appropriate adjustment of the molar ratio between the ditrimethylolpropane and the caprylic acid to achieve a hydroxyl value of 0 mgKOH/g, thus producing an esterified product.

(3) Specifically, first, 434.6 g (3.0 mol) of caprylic acid and 175.4 g (0.7 mol) of ditrimethylolpropane were placed in a four-neck flask, and under a stream of nitrogen, the mixture was heated to 230 to 240° C., and an esterification reaction was conducted for about 20 hours while the produced water was removed from the system. Following completion of the reaction, the excess acid was removed, yielding 476 g of the target esterified product.

(4) The obtained esterified product had an acid value of 0.1, and a hydroxyl value of 0.1 mgKOH/g.

[Example 7] Production of Esterified Product

(5) Using ditrimethylolpropane and caprylic acid as reaction raw materials, an esterification reaction was performed with appropriate adjustment of the molar ratio between the ditrimethylolpropane and the caprylic acid to achieve a hydroxyl value of 81 mgKOH/g, thus producing an esterified product.

(6) Specifically, first, 432.6 g (3.0 mol) of caprylic acid and 250.3 g (1.0 mol) of ditrimethylolpropane were placed in a four-neck flask, and under a stream of nitrogen, the mixture was heated to 230 to 240° C., and an esterification reaction was conducted for about 15 hours while the produced water was removed from the system. The acid value of the product was checked during the reaction, and the reaction was halted at the point where the acid value was confirmed as having reached approximately zero, thus obtaining 560 g of the targeted esterified product. The obtained esterified product had an acid value of 0.1, and a hydroxyl value of 81 mgKOH/g.

[Examples 1, 3 to 6, 8 to 19, and 27] Production of Esterified Products

(7) Using the alcohols and fatty acids shown in Tables 44 and 45 as reaction raw materials, esterified products of Examples 1, 3 to 6, 8 to 19, and 27 were produced in the same manner as the production of the esterified product of Example 2 or Example 7.

(8) The reaction raw materials, the hydroxyl value, and the properties (physical properties) at 35° C. of the obtained esterified products are shown in Tables 44 and 45.

(9) Further, for those esterified products produced using two types of fatty acids as raw materials, such as Examples 14 to 19 and 27, the composition of constituent fatty acid residues in the obtained esterified product was measured, and the mass ratio between each of the constituent fatty acid residues was calculated. Those values are shown in Tables 44 and 45. For example, as shown in Table 45, in the esterified product of Example 14, which was obtained by using linear fatty acids of 8 carbon atoms and 10 carbon atoms in a mass ratio of about 80:20 as reaction raw materials, the composition of the fatty acid residues was 8 carbon atoms: 10 carbon atoms=80:20 (mass ratio).

[Comparative Examples 1 to 8] Production of Esterified Products

(10) Using the alcohols and fatty acids shown in Table 46 as reaction raw materials, esterified products of Comparative Examples 1 to 8 were produced in the same manner as the production of the esterified product of Example 2 or Example 7.

(11) The reaction raw materials, the hydroxyl value, the mass ratio between the constituent fatty acid residues, and the properties (physical properties) at 35° C. of the obtained esterified products are shown in Table 46.

[Comparative Example 9] Production of Esterified Product

(12) Using 2-methyl-1-propanol and isostearic acid as reaction raw materials, an esterification reaction was performed with appropriate adjustment of the molar ratio between the 2-methyl-1-propanol and isostearic acid to achieve a hydroxyl value of 0 mgKOH/g, thus producing an esterified product.

(13) Specifically, 284.4 g (1 mol) of isostearic acid and 148.2 g (2 mol) of 2-methyl-1-propanol were placed in a four-neck flask, and under a stream of nitrogen, the mixture was heated to 210 to 220° C., and an esterification reaction was conducted for about 10 hours while the produced water was removed from the system. Following completion of the reaction, the excess alcohol was removed, yielding 251 g of an esterified product.

(14) The obtained esterified product (isobutyl isostearate) had an acid value of 0.1, and a hydroxyl value of 0.1 mgKOH/g.

(15) The reaction raw materials, the hydroxyl value, the mass ratio between the constituent fatty acid residues, and the properties (physical properties) at 35° C. of the obtained esterified products are shown in Table 46.

(16) <Measurement of Composition of Constituent Fatty Acid Residues of Esterified Product>

(17) In the following examples and the like, the mass ratio between the various constituent fatty acid residues of an esterified product were measured by preparing a derivative in which the fatty acid residues within the esterified product had been methyl esterified using a method corresponding with the 2.4.1.1-2013 methyl esterification method (sulfuric acid-methanol method) (Japan Oil Chemists' Society Standard Methods for the Analysis of Fats, Oils and Related Materials—2013 edition” published by Japan Oil Chemists' Society), and then separating and measuring the obtained derivative using a method corresponding with the 2.4.2.3-2013 fatty acid composition (capillary gas chromatograph method) (Japan Oil Chemists' Society Standard Methods for the Analysis of Fats, Oils and Related Materials—2013 edition” published by Japan Oil Chemists' Society).

(18) Specifically, one drop of the esterified product was first placed in a test tube and dissolved in 2 mL of a sulfuric acid-methanol solution (a solution prepared by mixing 2 mL of sulfuric acid with 230 mL of methanol). Subsequently, the test tube was heated, and a transesterification reaction was used to prepare a derivative in which the fatty acid residues in the esterified product had been methyl esterified.

(19) This methyl esterified derivative was dissolved in 2 mL of hexane and injected into the column of a gas chromatograph device fitted with a FID, and each of the methyl ester derivatives was separated and detected under the following GC analysis conditions.

(20) <GC Analysis Conditions>

(21) Column: DB-lht (manufactured by Agilent Technologies, Inc.)

(22) Injection volume: 1 μL

(23) Carrier gas: helium

(24) Column temperature: 50 to 370° C. (rate of temperature increase: 15° C./min)

(25) Identification of the peaks in the chromatograph was performed by comparison with the retention times for peaks obtained by analyzing standard substances under the same measurement conditions as the test sample. The composition of the fatty acid residues of the esterified product was calculated based on the percentage (%) of the peak surface area for the peak of the methyl ester derivative corresponding with each fatty acid residue in the chromatograph.

(26) Further, because a high-temperature compatible column is used in these GC analysis conditions, the esterified product could be injected directly into the gas chromatograph, and the ester composition of the esterified product in terms of the amounts of tetraester, triester, diester and monoester within each esterified product could also be calculated based on the percentage of the various peak surface areas in the chromatograph.

(27) <Skin Stratum Corneum Moisture Content Measurement Test>

(28) In the present invention, the moisture retention effect of the esterified product, namely the improvement effect on the moisture retention function of the skin, was evaluated based on the change in the stratum corneum moisture content of the skin before and after application of the esterified product.

(29) Measurement of the stratum corneum moisture content was performed using a stratum corneum moisture content measuring device (device name: SKICON-200), manufactured by IBS Co., Ltd. This stratum corneum moisture content measuring device is a device that is widely used for measuring the moisturestate of the stratum corneum, and is a device that measures the electrical conductivity (μS) of the stratum corneum. The larger the skin moisture content, the higher the electrical conductivity of the stratum corneum becomes. Accordingly, the electrical conductivity (μS) measured using the stratum corneum moisture content measuring device was deemed to indicate the stratum corneum moisture content.

(30) <Evaluation Test of Moisture Retention Effect Upon Single Application>

(31) The skin moisture retention effect of each test sample was evaluated by applying the test sample directly to washed skin, and then measuring the change in the skin stratum corneum moisture content after wiping the test sample off the skin using a cotton swab soaked in hexane.

(32) The skin stratum corneum moisture content measurement test was conducted on a plurality of panelists in the season from autumn to spring when the skin is prone to dryness. Further, in order to remove the effects of room temperature and humidity on the measurement results, the tests were performed in a room in which the room temperature had been adjusted to 18 to 22° C. and the humidity had been adjusted to 40 to 55% RH.

(33) Specifically, first, the forearm of the person was washed with soap, and the person was then held for 30 minutes in a room in which the room temperature and the humidity had been controlled within the above ranges to acclimatize the skin of the forearm to the measurement environment, thus completing preparations for the initial conditions for measurement.

(34) Then, a square portion of the forearm having a length of 3 cm and a width of 3 cm was designated as the measurement region, and the stratum corneum moisture content of the skin in that region was measured and recorded as a blank value (the stratum corneum moisture content prior to test commencement).

(35) Subsequently, 40 μL of the test sample being evaluated was applied uniformly to the square measurement region of the forearm. Sixty minutes after the application, a cotton swab that had been immersed in hexane was used to wipe off the test sample, and 30 minutes after the test sample had been wiped off, the stratum corneum moisture content of the wiped region of the skin (the stratum corneum moisture content upon test completion) was measured.

(36) Further, when evaluating the moisture retention effect of the test sample, in order to consider and subtract the change in the state of the skin during the measurement period, the stratum corneum moisture content of a portion of the skin to which the sample had not been applied was also measured prior to test commencement and upon test completion, and the change in the stratum corneum moisture content of this uncoated portion was calculated.

(37) A moisture retention effect value (μS) was determined from the measured values for the skin stratum corneum moisture content based on the formulas below. The moisture retention effect value (μS) for each test sample was calculated as the average value for the moisture retention effect values (μS) across five panelists.
[Moisture retention effect value(μS)]=[stratum corneum moisture content(μS) of applied region upon test completion]−[stratum corneum moisture content(μS) of blank]−[change in stratum corneum moisture content(μS) of uncoated portion]  (Formula 1)
[Change in stratum corneum moisture content(μS) of uncoated portion]=[stratum corneum moisture content(μS) of uncoated portion upon test completion]−[stratum corneum moisture content(μS) of uncoated portion prior to test commencement]  (Formula 2)

(38) Based on the moisture retention effect value (μS) for each test sample, the moisture retention effect of each test sample was evaluated using the criteria in Table 43. Test samples having a moisture retention evaluation of a1, b1 or c1 were adjudged to have a moisture retention effect, and were therefore useful as moisturizers, whereas test samples having an evaluation of d1 or e1 were adjudged to lack a satisfactory moisture retention effect, and were therefore not useful as moisturizers.

(39) TABLE-US-00044 TABLE 43 Moisture Retention Evaluation Criteria Usability as Evaluation Moisture retention effect value (μS) moisturizer a1 70 or greater yes b1 at least 60 but less than 70 yes c1 at least 50 but less than 60 yes d1 at least 40 but less than 50 no e1 less than 40 no
<Evaluation of Moisture Retention Effect Upon Single Application>

(40) Using each of the esterified products of Examples 1 to 19, Example 27, and Comparative Examples 1 to 9, the <Evaluation test of moisture retention effect upon single application> described above was conducted using five panelists to evaluate the moisture retention.

(41) However, because the surface temperature of the skin during testing is about 30 to 35° C., evaluation samples such as the esterified products of Comparative Example 1 and Comparative Example 8 that are solid at 35° C. could not be applied satisfactorily to the skin. Accordingly, for those esterified products that are solid at 35° C., the esterified product was mixed with cetyl 2-ethylhexanoate (product name “SALACOS 816T” manufactured by The Nisshin OilliO Group, Ltd.) in a mass a ratio of 1:1, and the resulting mixture that was liquid at 35° C. was used as the test sample for evaluation.

(42) TABLE-US-00045 TABLE 44 Reaction raw materials, physical properties, and moisture retention evaluation results for esterified products Con- stituent Appearance Moisture fatty acid at retention Moisture Reaction raw materials residue Hydroxyl 35° C. effect retention Fatty acid mass value (external value evaluation Alcohol (carbon atoms) ratio [mgKOH/g] appearance) [μS] result Example 1 Ditri- caproic acid (6) — 1 liquid 81 a1 Example 2 methylol caprylic acid (8) — 0 liquid 87 a1 Example 3 propane capric acid (10) — 0 liquid 70 a1 Example 4 lauric acid (12) — 1 liquid 76 a1 Example 5 caprylic acid (8) — 9 liquid 80 a1 Example 6 caprylic acid (8) — 14 liquid 87 a1 Example 7 caprylic acid (8) — 81 liquid 73 a1 Example 8 caprylic acid (8) — 105 liquid 65 b1 Example 9 caprylic acid (8) — 140 liquid 51 c1 Example 10 capric acid (10) — 102 liquid 52 c1

(43) TABLE-US-00046 TABLE 45 Reaction raw materials, physical properties, and moisture retention evaluation results for esterified products Con- stituent Appearance Moisture fatty acid at retention Moisture Reaction raw materials residue Hydroxyl 35° C. effect retention Fatty acid mass value (external value evaluation Alcohol (carbon atoms) ratio [mgKOH/g] appearance) [μS] result Example 11 Ditri- 2-ethylhexanoic — 0 liquid 51 c1 methylol acid (8) Example 12 propane 2-ethylhexanoic — 82 liquid 69 b1 acid (8) Example 13 3,5,5trimethyl — 2 liquid 55 c1 hexanoic acid (9) Example 14 caprylic acid (8)/ 80:20 0 liquid 70 a1 capric acid (10) Example 15 caprylic acid (8)/ 81:19 104 liquid 60 b1 capric acid (10) Example 16 caprylic acid (8)/ 90:10 0 liquid 78 a1 myristic acid (14) Example 17 caprylic acid (8)/ 80:20 0 liquid 67 b1 myristic acid (14) Example 18 caprylic acid (8)/ 70:30 1 liquid 60 b1 myristic acid (14) Example 19 caprylic acid (8)/ 60:40 1 liquid 58 c1 myristic acid (14) Example 27 caprylic acid (8)/ 70:30 1 liquid 68 b1 octyldodecanoic acid (20)

(44) TABLE-US-00047 TABLE 46 Reaction raw materials, physical properties, and moisture retention evaluation results for esterified products Con- stituent Appearance Moisture fatty acid at retention Moisture Reaction raw materials residue Hydroxyl 35° C. effect retention Fatty acid mass value (external value evaluation Alcohol (carbon atoms) ratio [mgKOH/g] appearance) [μS] result Comparative Ditri- myristic acid (14) — 1 liquid 44 d1 Example 1 methylol Comparative propane caprylic acid (8) — 148 liquid 42 d1 Example 2 Comparative isotridecanoic — 2 liquid 48 d1 Example 3 acid (13) Comparative caprylic acid (8)/ 50:50 1 liquid 48 d1 Example 4 myristic acid (14) Comparative caprylic acid (8) — 1 liquid 26 e1 Example 5 Trimethylol Comparative propane capric acid (10) — 1 liquid 36 e1 Example 6 Comparative Pentaeryth- caprylic acid (8) — 0 liquid 39 e1 Example 7 ritol Comparative capric acid (10) — 1 liquid 29 e1 Example 8 Comparative 2-methyl-1- isostearic — 0.1 liquid 47 d1 Example 9 propanol acid (18)

Comparative Examples 10 to 21

(45) Using various commercially available oils and glycerol, the <Evaluation of moisture retention upon single application> described above was conducted to ascertain the moisture retention effect. The properties (physical properties) of the commercially available oils and glycerol at 35° C. and the evaluation results are shown in Table 47.

(46) The glycerol of Comparative Example 21 is a typical aqueous moisturizer, and is widely used as a moisturizer. In the case of glycerol, removal of the glycerol that had been applied to the skin during the <Evaluation of moisture retention upon single application> described above was performed using a cotton swab that had been immersed in water rather than hexane. With the exception of changing the removal solvent from hexane to water, the evaluation conditions were the same as those described above in the <Evaluation of moisture retention upon single application>.

(47) TABLE-US-00048 TABLE 47 Properties and moisture retention evaluation results for various oils and glycerol Appearance Moisture Moisture at 35° C. retention retention (external effect evaluation Name appearance) value [μS] result Comparative 2-ethylhexyl palmitate liquid 26 e1 Example 10 (product name “SALACOS P-8”, manufactured by The Nisshin OilliO Group, Ltd.) Comparative Cetyl 2-ethylhexanoate liquid 26 e1 Example 11 (product name “SALACOS 816T”, manufactured by The Nisshin OilliO Group, Ltd.) Comparative Neopentyl glycol dicaprate liquid 22 e1 Example 12 (product name “ESTEMOL N-01”, manufactured by The Nisshin OilliO Group, Ltd.) Comparative Glyceryl tri(caprylate/caprate) liquid 26 e1 Example 13 (product name “O.D.O”, manufactured by The Nisshin OilliO Group, Ltd., constituent fatty acid ratio: caprylic acid/capric acid = 75/25) Comparative Glyceryl tri(2-ethylhexanoate) liquid 32 e1 Example 14 (product name “T.I.O”, manufactured by The Nisshin OilliO Group, Ltd.) Comparative Pentaerythrityl tetra(2-ethylhexanoate) liquid 27 e1 Example 15 (product name “SALACOS 5408”, manufactured by The Nisshin OilliO Group, Ltd.) Comparative Liquid paraffin liquid 31 e1 Example 16 Comparative Squalane liquid 35 e1 Example 17 Comparative Macadamia nut oil liquid 44 d1 Example 18 Comparative Castor oil liquid 47 d1 Example 19 Comparative Vaseline liquid 33 e1 Example 20 Comparative Glycerol liquid 8 e1 Example 21

(48) From the results in Tables 44 to 47, it was evident that the esterified products having a hydroxyl value of not more than 140 mgKOH/g of Examples 1 to 19 and Example 27, which used ditrimethylolpropane as the alcohol and a saturated fatty acid of 6 to 12 carbon atoms as the fatty acid as the raw materials for the esterification reaction, were oily substances which exhibited a high moisture retention effect value of at least 50 and a moisture retention evaluation of c1 or better, and were extremely useful as oily moisturizers. In contrast, the esterified products of Comparative Examples 5 to 9 which used an alcohol other than ditrimethylolpropane as the esterification reaction raw material, and the esterified products of Comparative Examples 1 and 3 which used ditrimethylolpropane as the alcohol raw material but used only a fatty acid of 13 or more carbon atoms as the fatty acid raw material, exhibited a moisture retention evaluation of d1 or poorer, and did not display a satisfactory moisture retention effect for use as a moisturizer. Furthermore, the esterified product of Comparative Example 2, which used ditrimethylolpropane as the alcohol raw material and used caprylic acid as the fatty acid, but had a hydroxyl value greater than 140 mgKOH/g, exhibited a moisture retention evaluation of d1, and did not display a satisfactory moisture retention effect for use as a moisturizer. Further, the esterified product of Comparative Example 4, which although using caprylic acid as a fatty acid raw material, has a low fatty acid residue proportion derived from caprylic acid (one of the saturated fatty acids of 6 to 12 carbon atoms) that represents only 50% of all of the constituent fatty acid residues in the obtained esterified product, exhibited a low moisture retention effect value of less than 50. Furthermore, although the oils of Comparative Examples 10 to 20 are all oils that have been conventionally used as raw materials for topical skin compositions, it was confirmed that the esterified products of Examples 1 to 19 and Example 27 which represent oily moisturizers according to the present invention exhibited superior moisture retention effects to the oils of Comparative Examples 10 to 20.

(49) The esterified products of Examples 1 to 19 and Example 27 were able to retain a high level of stratum corneum moisture content even after removal from the skin. It is thought that this indicates that these esterified products exhibit a moisture retention effect that relies on a mechanism of action that differs from that of conventional oily moisturizers which display a moisture retention effect by forming an oily film on the skin surface that suppresses moisture transpiration from the skin surface.

(50) Despite the fact that the glycerol of Comparative Example 21 is generally considered to have favorable moisture retention properties and is widely used as an aqueous moisturizer, the moisture retention evaluation result achieved in this test revealed a moisture retention effect value for glycerol of 8 μS, and a satisfactory moisture retention effect could not be confirmed. For reference purposes, after 60 minutes had elapsed from application of the glycerol, the skin stratum corneum moisture content with the glycerol still applied to the skin surface was measured prior to removal using water, and the increase in the electrical conductivity that corresponds with the moisture retention effect value was an extremely high numerical value of 477 μS, confirming why glycerol is said to be useful as a moisturizer. However, if the fact that glycerol is highly hygroscopic, and the fact that this numerical value decreases dramatically upon removal of the glycerol from the skin surface are taken into consideration, then it is surmised that this moisture retention effect of glycerol observed prior to removal represents a result of measuring a combination of the moisture content of the stratum corneum and the moisture content contained within the glycerol.

(51) <Evaluation of Sensation Upon Use>

(52) For topical skin compositions, an excellent sensation upon use is also very important for practical application.

(53) Accordingly, the esterified products of Example 1 and the like were subjected to sensory evaluations for sensation upon use, namely “lack of stickiness and good skin compatibility”.

(54) Specifically, four specialist evaluation panelists evaluated the sensation when a test sample of the evaluation target product was applied uniformly to the forearm on a five-grade scale (5 points: sensation upon use is good, 4 points: sensation upon use is fairly good, 3 points: sensation upon use is normal, 2 points: sensation upon use is slightly poor, 1 point: sensation upon use is poor). The evaluation score for the sensation upon use for each test sample was recorded as the average of the evaluation scores of the four panelists.

(55) Based on the evaluation score for the sensation upon use for each test sample, the sensation upon use of each test sample was evaluated against the criteria in Table 48. The evaluation results are shown in Table 49.

(56) TABLE-US-00049 TABLE 48 Sensation upon Use Evaluation Criteria Sensation upon use evaluation score (average) a2 greater than 4 points but not more than 5 points b2 greater than 3 points but not more than 4 points c2 greater than 2 points but not more than 3 points d2 greater than 1 point but not more than 2 points e2 1 point

(57) TABLE-US-00050 TABLE 49 Sensation upon Use Evaluation Results Sensation Sensation Sensation Evaluated upon use Evaluated upon use upon use esterified evaluation esterified evaluation Evaluated evaluation product result product result oil result Example 1 a2 Comparative e2 Comparative e2 Example 1 Example 21 Example 2 a2 Comparative e2 Example 2 Example 3 a2 Comparative e2 Example 3 Example 4 b2 Comparative c2 Example 4 Example 5 a2 Comparative a2 Example 5 Example 6 b2 Comparative a2 Example 6 Example 7 c2 Comparative a2 Example 7 Example 8 c2 Comparative e2 Example 8 Example 9 e2 Comparative a2 Example 9 Example 10 c2 Comparative a2 Example 10 Example 11 c2 Comparative a2 Example 11 Example 12 e2 Comparative a2 Example 12 Example 13 c2 Comparative a2 Example 13 Example 14 b2 Comparative a2 Example 14 Example 15 b2 Comparative a2 Example 15 Example 16 b2 Comparative a2 Example 16 Example 17 b2 Comparative a2 Example 17 Example 18 b2 Comparative a2 Example 18 Example 19 b2 Comparative e2 Example 19 Example 27 c2 Comparative e2 Example 20

(58) Based on the results in Table 49, it was evident that the esterified product that was an oily moisturizer according to the present invention exhibited a favorable sensation upon use, and also had an excellent overall evaluation as an oily moisturizer. In particular, the esterified products of Examples 1 to 3 in which the fatty acid residue were linear saturated fatty acid residues of 6 to 10 carbon atoms and the hydroxyl value was less than 10 mgKOH/g exhibited extremely superior results for both the moisture retention effect and the sensation upon use.

Examples 20 to 22, Comparative Examples 22 to 27

(59) Emulsions containing the esterified products of Examples 2, 3 and 8, the esterified product of Comparative Example 5 and the oils of Comparative Examples 11, 14, 16 and 18 were each investigated for moisture retention effect using a single application test (a test in which the number of repetitions of application to the skin surface was only one).

(60) Specifically, emulsions having the blend formulations shown in Tables 51 and 52 were first produced by the following steps A to C. A product “LASEMUL 92AE” manufactured by Industrial Quimica Lasem (IQL) was used as the glyceryl stearate, a product “LASEMUL 4000” manufactured by IQL was used as the PEG-100 stearate, and a product “Pemulen TR-1” manufactured by The Lubrizol Corporation was used as the (acrylates/alkyl acrylate (C10 to C30)) crosspolymer.

(61) A: components 1 and 2 were heated and mixed at 70° C.

(62) B: components 3 to 10 were heated and mixed uniformly at 70° C.

(63) C: the mixture obtained in step A was added to the mixture obtained in step B, and an emulsion was obtained by using an emulsifier (table-top Disper mixer) to perform an emulsification at 2,000 rpm and 70° C. for 5 minutes.

(64) <Evaluation Test of Moisture Retention Effect Upon Single Application of Emulsion>

(65) The emulsions of Examples 20 to 22 and Comparative Examples 22 to 27 were evaluated for moisture retention by 10 panelists.

(66) Specifically, the moisture retention effect of each emulsion containing an esterified product was evaluated by applying the emulsion containing the esterified product or oil to a washed portion of skin, washing the emulsion off with running water, and then measuring the stratum corneum moisture content of the skin.

(67) The skin stratum corneum moisture content measurement test was conducted in the season from autumn to spring when the skin is prone to dryness. Further, in order to remove the effects of room temperature and humidity on the measurement results, the tests were performed in a room in which the room temperature had been adjusted to 18 to 22° C. and the humidity had been adjusted to 40 to 55% RH.

(68) The skin stratum corneum moisture content was measured in the following manner.

(69) First, in the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the measurement portion was washed, the skin was left to acclimatize to the environment, a blank value measurement was performed, and an uncoated portion measurement was performed.

(70) Subsequently, 40 mg of the emulsion was applied uniformly to a square measurement region of the forearm. Five hours after the application, the coated portion of the skin was washed under running water (2 L/min) for 20 seconds, any excess water was then wiped away, and 30 minutes later, the stratum corneum moisture content (μS) was measured.

(71) Subsequently, in the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the average value of the moisture retention effect values from the 10 panelists, determined using formula 1 and formula 2, was recorded as the moisture retention effect value (μS) for the emulsion.

(72) Based on the moisture retention effect value (μS) for each emulsion, the moisture retention effect of each emulsion was evaluated based on the criteria in Table 50. Emulsions having a moisture retention evaluation of a3, b3 or c3 were adjudged to be useful as emulsions having a moisture retention effect, whereas emulsions having an evaluation of d3 or e3 were adjudged to lack a satisfactory moisture retention effect, and were therefore not useful as emulsions having a moisture retention effect. The evaluation results for the various emulsions are shown in Tables 51 and 52.

(73) TABLE-US-00051 TABLE 50 Moisture Retention Evaluation Criteria Usability as emulsion Moisture retention having a moisture Evaluation effect value (μS) retention effect a3 86 or greater yes b3 at least 76 but less than 86 yes c3 at least 66 but less than 76 yes d3 at least 56 but less than 66 no e3 less than 56 no

(74) TABLE-US-00052 TABLE 51 Emulsion blend formulations and moisture retention evaluation results upon single application Blend formulation [% by mass] Exam- Exam- Exam- Components (raw materials) ple 20 ple 21 ple 22 1 Esterified product (Example 2) 10.0 0 0 Esterified product (Example 3) 0 10.0 0 Esterified product (Example 8) 0 0 10.0 2 Cetanol 0.2 0.2 0.2 3 Glyceryl stearate 0.02 0.02 0.02 4 PEG-100 stearate 0.08 0.08 0.08 5 (Acrylates/alkyl acrylate (C10 to 15.0 15.0 15.0 C30)) crosspolymer 2% aqueous solution 6 Glycerol 2.0 2.0 2.0 7 1,3-butylene glycol 5.0 5.0 5.0 8 1% aqueous solution of sodium 6.0 6.0 6.0 hydroxide 9 Methylparaben 0.1 0.1 0.1 10 Water 61.6 61.6 61.6 Total 100.0 100.0 100.0 Moisture retention effect value [μS] 89 78 76 Moisture retention evaluation result a3 b3 b3

(75) TABLE-US-00053 TABLE 52 Emulsion blend formulations and moisture retention evaluation results upon single application Blend formulation [% by mass] Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative Components Example Example Example Example Example Example (raw materials) 22 23 24 25 26 27 1 Esterified product 10.0 0 0 0 0 0 (Comparative Example 5) Commercially available oil 0 10.0 0 0 0 0 (Comparative Example 11) Commercially available oil 0 0 10.0 0 0 0 (Comparative Example 14) Commercially available oil 0 0 0 10.0 0 0 (Comparative Example 16) Commercially available oil 0 0 0 0 10.0 0 (Comparative Example 18) 2 Cetanol 0.2 0.2 0.2 0.2 0.2 0.2 3 Glyceryl stearate 0.02 0.02 0.02 0.02 0.02 0.02 4 PEG-100 stearate 0.08 0.08 0.08 0.08 0.08 0.08 5 (Acrylates/alkyl acrylate 15.0 15.0 15.0 15.0 15.0 15.0 (C10 to C30)) crosspolymer 2% aqueous solution 6 Glycerol 2.0 2.0 2.0 2.0 2.0 2.0 7 1,3-butylene glycol 5.0 5.0 5.0 5.0 5.0 5.0 8 1% aqueous solution of 6.0 6.0 6.0 6.0 6.0 6.0 sodium hydroxide 9 Methylparaben 0.1 0.1 0.1 0.1 0.1 0.1 10 Water 61.6 61.6 61.6 61.6 61.6 71.6 Total 100.0 100.0 100.0 100.0 100.0 100.0 Moisture retention effect value [μS] 59 55 65 55 63 6 Moisture retention evaluation result d3 e3 d3 e3 e3 e3

(76) Based on Tables 51 and 52, it was evident that, compared with the emulsions of the various comparative examples, the emulsions containing an esterified product that was an oily moisturizer according to the present invention yielded a superior moisture retention effect even upon a single application to the skin surface and subsequent removal from the skin surface. Further, it was also confirmed that, compared with the emulsion that contained no oil (Comparative Example 27), adding an oily moisturizer yields an improved moisture retention effect value for the emulsion.

Examples 23 and 24, and Comparative Examples 28 and 29

(77) Emulsions containing the esterified product of Example 2 and the commercially available oil of Comparative Example 14 were used continuously for 3 weeks, and the moisture retention effect of these emulsions was investigated using the change in the skin stratum corneum moisture content before and after use as an indicator.

(78) Specifically, emulsions having the blend formulations shown in Table 54 were first produced by the following steps A to C. A product “LASEMUL 92AE” manufactured by Industrial Quimica Lasem, that is, IQL was used as the glyceryl stearate, a product “LASEMUL 4000” manufactured by IQL was used as the PEG-100 stearate, and a product “Pemulen TR-1” manufactured by The Lubrizol Corporation was used as the (acrylates/alkyl acrylate (C10 to C30)) crosspolymer.

(79) A: components 1 to 3 were heated and mixed at 70° C.

(80) B: components 4 to 11 were heated and mixed uniformly at 70° C.

(81) C: the mixture obtained in step A was added to the mixture obtained in step B, and an emulsion was obtained by using an emulsifier (table-top Disper mixer) to perform an emulsification at 2,000 rpm and 70° C. for 5 minutes.

(82) <Evaluation Test of Moisture Retention Effect Upon Continuous Application of Emulsion>

(83) The emulsions of Examples 23 and 24 and Comparative Examples 28 and 29 were evaluated for moisture retention by four panelists.

(84) Specifically, the moisture retention effect of each emulsion was evaluated by applying the evaluation target emulsion to a washed portion of the cheek surface once in the morning and once in the evening for a period of three weeks, and then measuring the stratum corneum moisture content of the cheek after the three-weeks period.

(85) The moisture retention effect evaluation test upon continuous application of the emulsion was conducted in the season from autumn to spring when the skin is prone to dryness. Further, in order to remove the effects of room temperature and humidity on the measurement results, the tests for measuring the skin stratum corneum moisture content were performed in a room in which the room temperature had been adjusted to 18 to 22° C. and the humidity had been adjusted to 40 to 55% RH.

(86) Specifically, first, a portion on the face of the person was washed with soap, and the person was then held for 30 minutes in a room in which the room temperature and the humidity had been controlled within the above ranges to acclimatize the skin of the facial surface, thus completing preparation of the measurement conditions.

(87) Then, a square portion of the washed cheek portion having a length of 3 cm and a width of 3 cm was designated as the measurement region, and the stratum corneum moisture content (μS) of the skin in that region was measured and recorded as a blank value (the stratum corneum moisture content (μS) prior to continuous test commencement).

(88) Subsequently, for a three-week period, about 0.4 g of the evaluation target emulsion was applied uniformly to the left and right washed facial surfaces once in the morning and once in the evening.

(89) The day following completion of the three-week period from the commencement of application, the stratum corneum moisture content (μS) of the skin of the cheek portion was measured in the same manner as prior to continuous test commencement and recorded as the stratum corneum moisture content (μS) upon continuous test completion.

(90) A moisture retention effect value (μS) was determined from the measured values for the skin stratum corneum moisture content based on the formulas below. The moisture retention effect value (μS) for each emulsion was calculated as the average value for the moisture retention effect values (μS) across the four panelists.
[Moisture retention effect value(μS)]=[stratum corneum moisture content(μS) upon continuous test completion]−[stratum corneum moisture content(μS)prior to continuous test commencement]  (Formula 3)

(91) Based on the moisture retention effect value (μS) for each emulsion, the moisture retention effect of each emulsion was evaluated using the criteria in Table 53. Emulsions having a moisture retention evaluation of a4, b4 or c4 were adjudged to be useful as emulsions having a moisture retention effect, whereas emulsions having an evaluation of d4 or e4 were adjudged to lack a satisfactory moisture retention effect, and were therefore not useful as emulsions having a moisture retention effect. The evaluation result for each emulsion is shown in Table 54.

(92) TABLE-US-00054 TABLE 53 Moisture Retention Evaluation Criteria Usability as emulsion Moisture retention having a moisture Evaluation effect value (μS) retention effect a4 110 or greater yes b4 at least 100 but less than 110 yes c4 at least 90 but less than 100 yes d4 at least 80 but less than 90 no e4 less than 80 no

(93) TABLE-US-00055 TABLE 54 Emulsion blend formulations and moisture retention evaluation upon continuous application Blend formulation [% by mass] Comparative Comparative Components (raw materials) Example 23 Example 24 Example 28 Example 29 1 Esterified product (Example 2) 10.0 5.0 0 0 Commercially available oil 0 0 10.0 5.0 (Comparative Example 14) 2 Liquid paraffin 0 5.0 0 5.0 3 Cetanol 0.5 0.5 0.5 0.5 4 Glyceryl stearate 0.1 0.1 0.1 0.1 5 PEG-100 stearate 0.4 0.4 0.4 0.4 6 (Acrylates/alkyl acrylate 10.0 10.0 10.0 10.0 (C10 to C30)) crosspolymer 2% aqueous solution 7 Glycerol 2.0 2.0 2.0 2.0 8 1,3-butylene glycol 5.0 5.0 5.0 5.0 9 1% aqueous solution of sodium 4.0 4.0 4.0 4.0 hydroxide 10 Methylparaben 0.1 0.1 0.1 0.1 11 Water 67.9 67.9 67.9 67.9 Total 100.0 100.0 100.0 100.0 Moisture retention effect value [μS] 156 136 84 77 Moisture retention evaluation result a4 a4 d4 e4

(94) As illustrated in Table 54, in the emulsion continuous application test, it was evident that compared with the emulsion containing Comparative Example 14 which is glyceryl tri(2-ethylhexanoate), the emulsion containing an esterified product that was an oily moisturizer according to the present invention yielded a superior moisture retention effect.

Examples 25 and 26, and Comparative Examples 30 to 32

(95) Cleansing oils containing the esterified products of Examples 2 and 3, the esterified product of Comparative Example 2, and the commercially available oils of Comparative Examples 10 and 16 were each investigated for moisture retention effect using a single application test.

(96) Specifically, the cleansing oils having the blend formulations shown in Table 56 were first produced by uniformly mixing the components 1 and 2 at 25° C. A product “SALACOS GE-318” manufactured by The Nisshin OilliO Group, Ltd. was used as the PEG-20 glyceryl triisostearate.

(97) <Evaluation Test of Moisture Retention Effect Upon Single Application of Cleansing Oil>

(98) The cleansing oils of Examples 25 and 26 and Comparative Examples 30 to 32 were evaluated for moisture retention by five panelists.

(99) Specifically, each cleansing oil containing an esterified product or oil was placed on a cleaned portion of skin and massaged for a certain period. Water was then added, and following formation of an emulsified state on the skin, the skin was washed with running water.

(100) The moisture retention effect of the cleansing oil containing the esterified product was evaluated by performing a stratum corneum moisture content measurement of the washed skin.

(101) The skin stratum corneum moisture content measurement test was conducted in the season from autumn to spring when the skin is prone to dryness. Further, in order to remove the effects of room temperature and humidity on the measurement results, the tests were performed in a room in which the room temperature had been adjusted to 18 to 22° C. and the humidity had been adjusted to 40 to 55% RH.

(102) The stratum corneum moisture content of the skin was measured in the following manner.

(103) In the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the measurement portion was washed, the skin was left to acclimatize to the environment, a blank value measurement was performed, and an uncoated portion measurement was performed.

(104) Subsequently, about 40 mg of the cleansing oil was applied uniformly to a square measurement region of the forearm. After the application, the coated forearm was massaged for 30 seconds. About 40 mg of water was then added, and following massaging for 30 seconds to emulsify the mixture, the forearm was washed under running water (2 L/min) for 20 seconds. The excess water was then wiped away, and 3 hours later, the stratum corneum moisture content (μS) was measured.

(105) Subsequently, in the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the average value of the moisture retention effect values from the five panelists, determined using formula 1 and formula 2, was recorded as the moisture retention effect value (μS) for the cleansing oil.

(106) Based on the moisture retention effect value (μS) for each cleansing oil, the moisture retention effect of each cleansing oil was evaluated using the criteria in Table 55. Cleansing oils having a moisture retention evaluation of a5, b5 or c5 were adjudged to be useful as cleansing oils having a moisture retention effect, whereas cleansing oils having an evaluation of d5 or e5 were adjudged to lack a satisfactory moisture retention effect, and were therefore not useful as cleansing oils having a moisture retention effect. The evaluation results for the various cleansing oils are shown in Table 56.

(107) TABLE-US-00056 TABLE 55 Moisture Retention Evaluation Criteria Usability as cleansing Moisture retention oil having a moisture Evaluation effect value (μS) retention effect a5 50 or greater yes b5 at least 43 but less than 50 yes c5 at least 36 but less than 43 yes d5 at least 29 but less than 36 no e5 less than 29 no

(108) TABLE-US-00057 TABLE 56 Cleansing oil blend formulations and moisture retention evaluation results upon single application Blend formulation [% by mass] Compar- Compar- Compar- ative ative ative Components Example Example Example Example Example (raw materials) 25 26 30 31 32 1 Esterified product 90.0 0 0 0 0 (Example 2) Esterified product 0 90.0 0 0 0 (Example 3) Esterified product 0 0 90.0 0 0 (Comparative Example 2) Commercially available oil 0 0 0 90.0 0 (Comparative Example 10) Commercially available oil 0 0 0 0 90.0 (Comparative Example 16) 2 PEG-20 glyceryl triisostearate 10.0 10.0 10.0 10.0 10.0 Total 100.0 100.0 100.0 100.0 100.0 Moisture retention effect value [μS] 50 40 35 17 21 Moisture retention evaluation result a5 c5 d5 e5 e5

(109) As illustrated in Table 56, it was evident that compared with the cleansing oils of the various comparative examples, the cleansing oils containing an esterified product that was an oily moisturizer according to the present invention yielded a superior moisture retention effect.

Examples 28 to 30, and Comparative Examples 33 and 34

(110) Ointments containing the esterified products of Example 2, Example 5 and Example 14, and the commercially available oils of Comparative Examples 14 and 16 were each investigated for moisture retention effect using a single application test.

(111) Specifically, the ointments having the blend formulations shown in Table 58 were first produced by heating and uniformly mixing the components 1 and 2 at 90° C. A product “Rheopearl KL” manufactured by Chiba Flour Milling Co., Ltd. was used as the dextrin palmitate.

(112) <Evaluation Test of Moisture Retention Effect Upon Single Application of Ointment>

(113) The ointments of Examples 28 to 30 and Comparative Examples 33 and 34 were evaluated for moisture retention by five panelists.

(114) Specifically, each ointment containing an esterified product or oil was placed on a cleaned portion of skin, and after one hour, a cotton swab that had been immersed in hexane was used to wipe off the ointment, and the moisture retention effect of the ointment containing the esterified product was evaluated based on the change in the stratum corneum moisture content of the skin.

(115) The stratum corneum moisture content of the skin was measured in the following manner.

(116) In the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the measurement portion was washed, the skin was left to acclimatize to the environment, a blank value measurement was performed, and an uncoated portion measurement was performed.

(117) Subsequently, about 40 mg of the ointment was applied uniformly to a square measurement region of the forearm. After one hour had elapsed, the ointment was wiped off with a cotton swab that had been immerse in hexane, and 30 minutes later, the skin stratum corneum moisture content was measured.

(118) Then, in the same manner as described above in the <Evaluation test of moisture retention effect upon single application>, the average value of the moisture retention effect values from the five panelists, determined using formula 1 and formula 2, was recorded as the moisture retention effect value (μS) for the ointment.

(119) Based on the moisture retention effect value (μS) for each ointment, the moisture retention effect of each ointment was evaluated using the criteria in Table 57. Ointments having a moisture retention evaluation of a6, b6 or c6 were adjudged to be useful as ointments having a moisture retention effect, whereas ointments having an evaluation of d6 or e6 were adjudged to lack a satisfactory moisture retention effect, and were therefore not useful as ointments having a moisture retention effect. The evaluation results for the various ointments are shown in Table 58.

(120) TABLE-US-00058 TABLE 57 Moisture Retention Evaluation Criteria Usability as ointment Moisture retention having a moisture Evaluation effect value (μS) retention effect a6 45 or greater yes b6 at least 40 but less than 45 yes c6 at least 35 but less than 40 yes d6 at least 30 but less than 35 no e6 less than 30 no

(121) TABLE-US-00059 TABLE 58 Ointment blend formulations and moisture retention evaluation results upon single application Blend formulation [% by mass] Compar- Compar- ative ative Components Example Example Example Example Example (raw materials) 28 29 30 33 34 1 Esterified product 96.0 0 0 0 0 (Example 2) Esterified product 0 96.0 0 0 0 (Example 5) Esterified product 0 0 96.0 0 0 (Example 14) Commercially available oil 0 0 0 96.0 0 (Comparative Example 14) Commercially available oil 0 0 0 0 96.0 (Comparative Example 16) 2 Dextrin palmitate 4.0 4.0 4.0 4.0 4.0 Total 100.0 100.0 100.0 100.0 100.0 Moisture retention effect value [μS] 54 50 46 26 24 Moisture retention evaluation result a6 a6 a6 e6 e6

(122) As illustrated in Table 58, it was evident that compared with the ointments of the various comparative examples, the ointments containing an esterified product that was an oily moisturizer according to the present invention yielded a superior moisture retention effect.

INDUSTRIAL APPLICABILITY

(123) The present invention is able to provide an oily moisturizer having an excellent skin moisture retention effect, and a topical skin composition containing the oily moisturizer.