A wax composition for cosmetics, and a method for improving the storage stability of cosmetics and making cosmetics easily washable.

Abstract

The present invention provides a wax composition for cosmetics that can suppress the deterioration of storage stability of cosmetics in low-temperature, low-humidity or high-temperature, high-humidity environments, and improve the washability of cosmetics. [Solution] A cosmetic wax composition containing an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, wherein the ester contains tetraester T, the content of tetraester T in the wax composition is 80 to 98% by mass, the wax composition has an acid value of 2 mg KOH / g or less, a hydroxyl value of 1 mg KOH / g or more and 10 mg KOH / g or less, and a melting point of 75°C or higher.

Description

[Technical Field]

[0001] The present invention relates to a wax composition for cosmetics, and a method for improving the storage stability of cosmetics and making cosmetics easily washable using the said wax composition. [Background technology]

[0002] Waxes, typified by hydrocarbons that are solid at room temperature, are used to thicken or solidify cosmetics. In recent years, due to growing global environmental awareness, waxes made from plant-derived raw materials have attracted attention, and ester waxes, composed of fatty acid esters, are being investigated as representative plant-derived waxes. Examples of cosmetics in which such waxes are suitably used include non-aqueous oil-based cosmetics such as lipsticks and cleansing balms, oil-in-water emulsion cosmetics such as hand creams and face creams, and water-in-oil emulsion cosmetics such as sunscreens. All of these cosmetics require storage stability.

[0003] For example, Patent Document 1 states that a solid wax composition containing candelilla wax and a monoester with a total carbon number of 40 to 48 has an excellent hardness-adjusting effect and can be used as a solidifying agent for various cosmetics, and that cosmetics containing this composition can be given excellent shape retention, an effect of suppressing oil stains during use, a good feel, and storage stability.

[0004] Furthermore, in recent years, for the purpose of reducing the burden on the skin of cosmetics, cosmetics are also required to be easily washed off with water, that is, to have excellent water washability. For example, in Patent Document 2, an oil-based cleansing cosmetic containing a polyglycerol fatty acid ester esterified with a polyglycerol having a glycerol polymer content of 20% or less and an average degree of polymerization calculated from the hydroxyl value of 10 to 20 and a fatty acid having 12 to 22 carbon atoms is disclosed. It is described that the oil-based cleansing cosmetic contains the above specific polyglycerol fatty acid ester, is excellent in makeup compatibility and water washability during washing, and has no oily or dry feeling after cleansing.

[0005] On the other hand, in recent years, with the diversification of the usage environment and rapid environmental changes, storage stability in a wide range of environments from low-temperature and low-humidity environments to high-temperature and high-humidity environments has been required. Cosmetics containing wax may have deteriorated storage stability due to changes in the crystallinity of the wax in low-temperature and low-humidity environments or high-temperature and high-humidity environments. However, in Patent Documents 1 and 2, sufficient investigations on storage stability in low-temperature and low-humidity environments and high-temperature and high-humidity environments have not been made.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a wax composition for cosmetics that can suppress deterioration of the storage stability of cosmetics in low-temperature and low-humidity environments or high-temperature and high-humidity environments and improve the water washability of cosmetics. Furthermore, the present invention aims to provide a method for improving the storage stability of cosmetics containing oils and waxes and for making such cosmetics easily washable. [Means for solving the problem]

[0008] The inventors have discovered that a wax composition containing a specific tetraester and having a specific acid value, hydroxyl value, and melting point can improve the storage stability and water washability of cosmetics, and have completed the present invention.

[0009] In other words, the present invention is as follows: [1] A cosmetic wax composition containing an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, The ester contains a tetraester T represented by the following structural formula (I), and the content of the tetraester T in the wax composition is 80 to 98% by mass. The wax composition is a cosmetic wax composition having an acid value of 2 mg KOH / g or less, a hydroxyl value of 1 mg KOH / g or more and 10 mg KOH / g or less, and a melting point of 75°C or higher.

[0010] [ka] [In structural formula (I), R 1 CO, R 2 CO, R 3 CO and R 4 CO independently represents a straight-chain saturated acyl group with 14 to 26 carbon atoms.

[0011] [2] The ester further contains a partial ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, and the content of the partial ester in the wax composition is 2 to 20% by mass. The cosmetic wax composition according to [1], wherein the linear saturated fatty acid having 14 to 26 carbon atoms comprises 90% by mass or more of a linear saturated fatty acid having 18 to 22 carbon atoms.

[0012] [3] A method for improving the storage stability of a cosmetic composition and making the cosmetic composition easily washable, wherein the wax composition is the cosmetic wax composition described in [1] or [2] in a cosmetic composition containing an oil and a wax. [Effects of the Invention]

[0013] The wax composition for cosmetics of the present invention can suppress the deterioration of storage stability of cosmetics in low-temperature, low-humidity environments or high-temperature, high-humidity environments, and can improve the washability of cosmetics. Furthermore, the present invention provides a method for improving the storage stability of cosmetics containing oils and waxes, and for making such cosmetics easily washable. [Modes for carrying out the invention]

[0014] The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described herein and can be modified in various ways without departing from the spirit of the invention. The "cosmetic wax composition" of the present invention may sometimes be simply referred to as "wax composition." Furthermore, in this invention, a numerical range defined using the symbol "~" includes the numerical values ​​at both ends (upper and lower limits) of "~". For example, "2~10" represents the range of 2 to 10. Furthermore, among the numerical values ​​described to explain the present invention, the numerical values ​​that may include decimal places are, unless otherwise specified, obtained by rounding a digit that was one place smaller than the smallest digit included in the numerical value. Furthermore, within the numerical range described in the present invention, the upper or lower limit of that numerical range can be replaced with the values ​​shown in the examples or values ​​uniquely derived from the examples.

[0015] The cosmetic wax composition of the present invention contains an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, wherein the ester contains a tetraester T represented by the above structural formula (I), the content of the tetraester T in the wax composition is 80 to 98% by mass, the acid value is 2 mg KOH / g or less, the hydroxyl value is 1 mg KOH / g or more and 10 mg KOH / g or less, and the melting point is 75°C or higher. Cosmetics containing oils and waxes may experience deterioration in storage stability under low-temperature, low-humidity or high-temperature, high-humidity conditions. However, by using the cosmetic wax composition of the present invention as the wax, the deterioration of storage stability of cosmetics under both low-temperature, low-humidity and high-temperature, high-humidity conditions can be suppressed. Furthermore, since the cosmetic wax composition of the present invention can improve the water-washability of cosmetics containing oils, cosmetics containing the cosmetic wax composition of the present invention are easily washed off with water after application to the skin. Therefore, in a cosmetic composition containing an oil and a wax, the storage stability of the cosmetic composition can be improved and the cosmetic composition can be made easily washable by using the cosmetic wax composition of the present invention as the wax. Here, improving the storage stability of the cosmetic composition means that by using the cosmetic wax composition of the present invention, at least one of the deterioration of the storage stability of the cosmetic composition in a low-temperature, low-humidity environment and the deterioration of the storage stability of the cosmetic composition in a high-temperature, high-humidity environment can be suppressed. Furthermore, making the cosmetic composition easily washable means that by using the cosmetic wax composition of the present invention, the cosmetic composition exhibits good washability without significantly worsening the washability of the cosmetic composition, or by maintaining or improving the washability of the cosmetic composition.

[0016] 〔ester〕 The wax composition for cosmetics of the present invention contains an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. The ester contains at least the following tetraester T, which is a tetraester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, and may further contain a partial ester. The ester may be an ester synthesized collectively using a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol.

[0017] (Tetraester T) The tetraester T contained in the wax composition for cosmetics of the present invention is a pentaerythritol tetraester represented by the following structural formula (I).

[0018] [Chemical formula] [In the structural formula (I), R 1 CO, R 2 CO, R 3 CO and R 4 CO each independently represent a linear saturated acyl group having 14 to 26 carbon atoms.

[0019] The wax composition of the present invention may contain only one kind of compound as the above tetraester T, or may contain a combination of two or more kinds of compounds. In the present invention, without distinguishing each of R 1 CO, R 2 CO, R 3 CO and R 4 CO, stereoisomers of the compound represented by the above structural formula (I) are regarded as the same tetraester T. For example, when the number of carbon atoms of R 1 CO, R 2 CO, R 3 CO and R 4 CO are respectively represented as C1, C2, C3 and C4, the tetraester T of the following example (1) and the tetraester T of the following example (2) are regarded as the same in the present invention. Example (1): C1 = 18, C2 = 20, C3 = 22, C4 = 24 Example (2): C1=18, C2=22, C3=20, C4=24

[0020] R in the above structural formula (I) 1 CO, R 2 CO, R 3 CO and R 4 CO are each independently linear saturated acyl groups having 14 to 26 carbon atoms, and are residues of linear saturated fatty acids having 14 to 26 carbon atoms used as raw materials. From the standpoint of suppressing deterioration of the storage stability of cosmetics and improving the washability of cosmetics, R 1 CO, R 2 CO, R 3 CO and R 4 CO is preferably a linear saturated acyl group with 16 to 24 carbon atoms, independently of each other. 1 CO, R 2 CO, R 3 CO and R 4 It is preferable that the linear saturated acyl group represented by CO contains at least one linear saturated acyl group having 18 to 22 carbon atoms.

[0021] Specific examples of the above-mentioned tetraester T include pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol tetrapalmitate, pentaerythritol tetraarachidate, pentaerythritol tetralignocellate, pentaerythritol monostearate tribehenate, pentaerythritol monoarachidate tribehenate, pentaerythritol monolignocellate tribehenate, pentaerythritol monopalmitate tristearate, and pentaerythritol monostearate tripalmitate. In particular, from the standpoint of suppressing deterioration of the storage stability of the cosmetic and improving the washability of the cosmetic, at least one selected from the group consisting of pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol tetrapalmitate, pentaerythritol tetraarachidate, pentaerythritol monostearate tribehenate, and pentaerythritol monoarachidate tribehenate is preferably used, at least one selected from the group consisting of pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol monostearate tribehenate, and pentaerythritol monoarachidate tribehenate is more preferably used, and at least one selected from the group consisting of pentaerythritol tetrastearate and pentaerythritol tetrabehenate is particularly preferably used.

[0022] (Partial ester) The cosmetic wax composition of the present invention may further contain a partial ester as an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. This further suppresses deterioration of the storage stability of the cosmetic and improves the washability of the cosmetic. The partial ester may be a monoester, a diester, or a triester.

[0023] Examples of linear saturated fatty acids having 14 to 26 carbon atoms used in esters of linear saturated fatty acids having 14 to 26 carbon atoms with pentaerythritol include myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, and cerotic acid. In particular, at least one selected from the group consisting of palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid is preferably used, and at least one selected from the group consisting of stearic acid, arachidic acid, and behenic acid is more preferably used, from the viewpoint of suppressing deterioration of the storage stability of cosmetics and improving washability. From a similar viewpoint, it is preferable that the above-mentioned linear saturated fatty acids having 14 to 26 carbon atoms contain linear saturated fatty acids having 18 to 22 carbon atoms in a proportion of 90% by mass or more, and more preferably 95% by mass or more. Furthermore, in order to suppress deterioration of the storage stability of cosmetics and improve washability, it is more preferable that the straight-chain saturated fatty acids having 14 to 26 carbon atoms are only straight-chain saturated fatty acids having 16 to 24 carbon atoms.

[0024] The straight-chain saturated fatty acids having 14 to 26 carbon atoms described above may consist of only one type of fatty acid, or they may contain a combination of two or more types of fatty acids. The amount of the fatty acid with the highest content among the fatty acids contained in the straight-chain saturated fatty acids having 14 to 26 carbon atoms is not particularly limited, but in order to suppress deterioration of the storage stability of the cosmetic and improve its washability, it is preferable that it be 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, when the total amount of straight-chain saturated fatty acids having 14 to 26 carbon atoms is taken as 100% by mass. Similarly, it is preferable that it be 99% by mass or less, more preferably 94% by mass or less, and even more preferably 92% by mass or less.

[0025] [Wax composition for cosmetic use] The cosmetic wax composition of the present invention has a tetraester T content of 80 to 98% by mass when the wax composition is considered as 100% by mass. Preferably, the tetraester T content is 90 to 96% by mass, from the viewpoint of suppressing deterioration of the storage stability of the cosmetic and improving the washability of the cosmetic. When the cosmetic wax composition of the present invention contains two or more types of tetraester T, the tetraester T content is the total content of the multiple types of tetraester T.

[0026] Of the tetraester T contained in the cosmetic wax composition of the present invention, the tetraester T with the highest content A The content of is preferably 15 to 95% by mass, more preferably 17 to 80% by mass, and even more preferably 30 to 70% by mass, when the wax composition is considered as 100% by mass, in order to suppress deterioration of the storage stability of the cosmetic and to improve the washability of the cosmetic. Furthermore, the above-mentioned tetraester T contained in the wax composition of the present invention A This may consist of only one type or two or more types. The above tetraester T contained in the wax composition A If there are multiple types, the above tetraester T A The content of various tetraesters T A The content shall be as follows.

[0027] In the present invention, among the one or more tetraesters T contained in the wax composition, the tetraester T with the highest content is referred to as "tetraester T" as described above. A " and the tetraester T A A different tetraester T is called "tetraester T B It may be referred to as ". If the wax composition contains only one type of tetraester T, then that one type of tetraester T is tetraester T A That is the case.

[0028] When the wax composition of the present invention contains a partial ester as an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, the content of the partial ester is not particularly limited, but from the viewpoint of further suppressing deterioration of the storage stability of the cosmetic and improving the washability of the cosmetic, it is preferably 2 to 20% by mass, more preferably 4 to 10% by mass, when the wax composition is considered as 100% by mass.

[0029] In the wax composition of the present invention, the content of the ester between a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, that is, the sum of the content of the tetraester T and the content of the partial ester, is not particularly limited, but from the viewpoint of further suppressing deterioration of the storage stability of the cosmetic and improving the washability of the cosmetic, it is preferably 98% by mass or more, more preferably 99% by mass or more, and may be 100% by mass, when the wax composition is considered as 100% by mass.

[0030] The wax composition of the present invention may further contain a component X different from the ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. Examples of component X include pentaerythritol as a raw material alcohol and a linear saturated fatty acid having 14 to 26 carbon atoms as a raw material fatty acid. Furthermore, component X may be unreacted raw materials, by-products, or impurities derived from the raw materials that remain in the wax composition, or it may be intentionally added.

[0031] The content of each component constituting the cosmetic wax composition can be calculated, for example, from the amount of raw materials added during manufacturing, or it can be measured by analyzing the wax composition using gas chromatography (GC). In this invention, the numerical value of the content shall be an integer value rounded to the first decimal place.

[0032] The cosmetic wax composition of the present invention has an acid value AV of 2 mg KOH / g or less and a hydroxyl value OHV of 1 mg KOH / g or more and 10 mg KOH / g or less, that is, satisfies the following formulas (1) and (2). From the viewpoint of suppressing deterioration of the storage stability of cosmetics and improving the washability of cosmetics, the acid value AV of the cosmetic wax composition of the present invention is preferably 1 mg KOH / g or less, and more preferably 0.1 mg KOH / g or less. Furthermore, from the viewpoint of suppressing deterioration of the storage stability of cosmetics and improving the washability of cosmetics, the hydroxyl value OHV of the cosmetic wax composition of the present invention is preferably 5 mg KOH / g or less, and more preferably 4 mg KOH / g or less. AV ≤ 2 (1) 1 ≤ OHV ≤ 10 (2) Furthermore, the acid value AV of the cosmetic wax composition of the present invention can be adjusted by adjusting the reaction conditions or the ratio of raw materials used when synthesizing the ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, or by adjusting the purification conditions when purifying the crude product of the ester by recrystallization or neutralization washing, or by incorporating fatty acids into the wax composition. The hydroxyl value (OHV) of the cosmetic wax composition of the present invention can be adjusted by adjusting the reaction conditions or the ratio of raw materials used when synthesizing the ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, or by adjusting the purification conditions when purifying the crude product of the ester by recrystallization or the like, or by incorporating a partial ester into the wax composition.

[0033] The melting point of the cosmetic wax composition of the present invention is 75°C or higher. From the standpoint of suppressing deterioration of the storage stability of cosmetics and improving the washability of cosmetics, the melting point of the cosmetic wax composition of the present invention is preferably 78°C or higher, more preferably 80°C or higher, and similarly, preferably 95°C or lower, more preferably 90°C or lower. In this invention, the melting point of the wax composition refers to the temperature of the endothermic peak during melting of the wax composition, as measured by a differential scanning calorimeter (DSC). The melting point of the cosmetic wax composition of the present invention can be adjusted by adjusting the reaction conditions or the ratio of raw materials when synthesizing the ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, or by adjusting the purification conditions when purifying the crude product of the ester by recrystallization or neutralization washing, or by incorporating fatty acids or partial esters into the wax composition.

[0034] Since the wax composition of the present invention is typically used by being melted and mixed with a base oil (oil agent) during the manufacture of cosmetics, the wax composition of the present invention before being added to cosmetics may be a composition that has been uniformly mixed beforehand, or it may be a composition obtained by physically mixing finely ground materials of each component constituting the wax composition of the present invention.

[0035] The method for producing the cosmetic wax composition of the present invention is not particularly limited, as long as it is a method that yields the wax composition of the present invention as described above. As an example of a method for producing the cosmetic wax composition of the present invention, a method can be cited that includes the steps of obtaining a crude ester product of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, and purifying the crude product.

[0036] The process of obtaining a crude ester product of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol is carried out, for example, by dehydration condensation reaction between a raw material fatty acid containing a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. The above raw material fatty acids mainly consist of straight-chain saturated fatty acids having 14 to 26 carbon atoms, and their purity may be less than 100% by mass. Preferably, the main component is a straight-chain saturated fatty acid having 18 to 22 carbon atoms. In the present invention, the purity of the raw material fatty acids is the content of the most abundant fatty acid when the total amount of raw material fatty acids is taken as 100% by mass. Furthermore, the above raw material fatty acids may consist only of straight-chain saturated fatty acids having 14 to 26 carbon atoms, or only of straight-chain saturated fatty acids having 16 to 24 carbon atoms. Alternatively, the above raw material fatty acids may contain components other than straight-chain saturated fatty acids having 14 to 26 carbon atoms. Although not particularly limited, from the viewpoint of obtaining a wax composition that easily suppresses deterioration of the storage stability of cosmetics and easily improves the washability of cosmetics, the content of straight-chain saturated fatty acids having 14 to 26 carbon atoms in 100% by mass of the total amount of the above raw material fatty acids is preferably 95% by mass or more, and more preferably 99% by mass or more.

[0037] The crude ester product of straight-chain saturated fatty acids with 14-26 carbon atoms and pentaerythritol is tetraester T, which has the highest content. A It contains at least one of the following. When a raw material fatty acid containing two or more straight-chain saturated fatty acids with 14 to 26 carbon atoms is used, the crude product is tetraester T as the main product. A It contains tetraester T as a byproduct. B It contains [the specified compound]. Furthermore, the crude product typically further contains partial esters of a straight-chain saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. The amount of partial ester produced can be adjusted by the ratio of the raw materials used, the reaction conditions, etc.

[0038] In the purification process of the crude product described above, it is preferable to reduce the content of unreacted raw material fatty acids contained in the crude product. This makes it possible to set the acid value of the final wax composition to 2 mg KOH / g or less. Examples of purification processes include distillation, recrystallization, and liquid-liquid treatment using a basic aqueous solution. It is particularly preferable to reduce the content of unreacted fatty acids by liquid-liquid treatment using a basic aqueous solution. In the step of purifying the crude product described above, the cosmetic wax composition of the present invention may be obtained by purifying the crude product. Alternatively, after obtaining the purified ester by purifying the crude product described above, the cosmetic wax composition of the present invention may be obtained by mixing the purified ester with the above-mentioned component X, or an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, or both thereof, which is prepared separately.

[0039] There are no particular restrictions on the use of the cosmetic wax composition of the present invention in the cosmetic composition. The cosmetic wax composition of the present invention can be used as a wax in cosmetic compositions containing oils, such as oil-based solid cosmetics, oil-in-water emulsion cosmetics, or water-in-oil emulsion cosmetics. In particular, the effects of the wax composition of the present invention are easily exhibited, so it is preferable to use the cosmetic wax composition of the present invention in oil-based cosmetics, and more preferably in oil-based solid cosmetics. Furthermore, since the cosmetic wax composition of the present invention can improve the water-washability of cosmetics, it is particularly preferable to use it in cosmetics that require water-washability, such as oil-based cleansing cosmetics like cleansing balms.

[0040] There are no particular limitations on the method for producing cosmetics containing the wax composition for cosmetics of the present invention, and they can be produced by known methods. Examples of methods for producing cosmetics are shown below, but are not limited thereto. For example, first, the wax composition of the present invention is heated and melted. Base oil and other components are added to the resulting solution. The mixture thus obtained can be filled into a container and, if necessary, molded to obtain cosmetics containing the wax composition of the present invention. Although there are no particular limitations, in order to effectively exert the effects of the wax composition of the present invention, it is preferable to heat and melt the wax composition of the present invention in a base oil and then cool and solidify it before use, as described above.

[0041] In a cosmetic composition containing the wax composition of the present invention, the content of the wax composition of the present invention is not particularly limited, but from the standpoint of easily obtaining the effects of the wax composition of the present invention, it is preferably 1 to 30% by mass, more preferably 3 to 30% by mass, even more preferably 5 to 20% by mass, and even more preferably 7 to 15% by mass, based on 100% by mass of the cosmetic composition. Furthermore, in cosmetics containing the wax composition of the present invention, the effects of the wax composition of the present invention are easily obtained, so the mass ratio of the base oil to the wax composition of the present invention (base oil:wax composition) is preferably in the range of 97:3 to 70:30, more preferably in the range of 95:5 to 80:20, and even more preferably in the range of 93:7 to 85:15.

[0042] The wax composition of the present invention is preferably used by adding it to a base oil containing at least one selected from the group consisting of hydrocarbon oils and ester oils. This makes it easier to obtain the effects of the wax composition of the present invention. Examples of hydrocarbon oils include straight-chain alkanes such as decane, dodecane, and tetradecane, as well as branched alkanes such as hydrogenated polyisobutene and squalane. Examples of ester oils include vegetable oils such as olive oil, as well as synthetic oils such as tri(caprylic / caprin), cetyl ethylhexanoate, hexyl laurate, polyglycerin isostearate, and medium-chain triglyceride. [Examples]

[0043] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, parts and percentages are by mass.

[0044] In the following, the acid value (AV) was measured in accordance with JOCS (Japan Oil Chemists' Society) 2.3.1-1996, and the hydroxyl value (OHV) was measured in accordance with JOCS (Japan Oil Chemists' Society) 2.3.6.2-1996. Also, the conditions for gas chromatography (GC) were as follows. <GC Conditions> Gas chromatograph: Nexis GC-2030, manufactured by Shimadzu Corporation Column: MXT (registered trademark)-1HT Sim Dist (inner diameter 0.53 mm, length 10 m), manufactured by RESTEK Column temperature: The temperature was raised from an initial temperature of 100°C at a rate of 10°C / min to 430°C and held at 430°C for 10 minutes. Injection temperature: 430°C Detection temperature: 430°C

[0045] [Synthesis of Wax Composition] Using the raw material fatty acids shown in Table 1 and pentaerythritol (Perstorp's "Penta mono" with a pentaerythritol purity of 99%), wax compositions W-1 to W-13 shown in Table 2 were obtained by the method shown in the following synthesis examples.

[0046] [Synthesis Example 1: Synthesis of Wax Composition W-1] Into a 3 L four-necked flask equipped with a thermometer, a nitrogen inlet tube, a stirring blade, and a condenser, 200 g (1.47 mol) of pentaerythritol and 2058.5 g (6.05 mol) of fatty acid FA-1 were added, and the reaction was carried out at 240°C under a nitrogen stream. The obtained crude ester product was 2232.3 g, and the acid value was 8.7 mgKOH / g. 900 g of toluene and 500 g of 2-propanol were added to this crude ester product, and a 10 mass% potassium hydroxide aqueous solution containing an amount of potassium hydroxide equivalent to 2.0 times the residual acid value of the crude ester product was added, and the mixture was stirred at 70°C for 30 minutes. Then, it was allowed to stand for 30 minutes, and the aqueous layer (lower layer) was separated and removed. Washing with water was repeated 4 times until the pH of the drained water became neutral. The solvent in the remaining ester layer was distilled off under reduced pressure conditions of 180°C and 1 kPa, and filtration was performed to obtain 1800.7 g of wax composition W-1.

[0047] [Synthesis Example 2: Synthesis of Wax Composition W-2] In a 3 L four-necked flask equipped with a thermometer, nitrogen inlet tube, stirring blade, and condenser, 200 g (1.47 mol) of pentaerythritol and 2020.7 g (6.05 mol) of fatty acid FA-2 were added and reacted at 240 °C under a nitrogen stream. The resulting crude ester product was 2202.3 g with an acid value of 8.1 mg KOH / g. To the crude ester product, 900 g of toluene and 500 g of 2-propanol were added, and a 10% by mass potassium hydroxide aqueous solution containing an amount of potassium hydroxide equivalent to 2.0 times the residual acid value of the crude ester product was added. The mixture was stirred at 70°C for 30 minutes. After that, it was allowed to stand for 30 minutes to separate and remove the aqueous layer (lower layer). The mixture was washed with water four times until the pH of the wastewater became neutral. The solvent in the remaining ester layer was removed by distillation under reduced pressure of 1 kPa at 180°C, and the mixture was filtered to obtain 1785.7 g of wax composition W-2.

[0048] <Synthesis Example 3: Synthesis of Wax Composition W-3> Wax composition W-3 was obtained in the same manner as in Synthesis Example 2, except that the amount of fatty acid FA-2 added was changed to 1963.9 g (5.88 mol).

[0049] <Synthesis Example 4: Synthesis of Wax Composition W-4> Wax composition W-4 was obtained by weighing 100g of wax composition W-3 obtained in Synthesis Example 3 and 0.9g of fatty acid FA-2 into a glass petri dish and melting and mixing them on a hot plate heated to 120°C.

[0050] <Synthesis Example 5: Synthesis of Wax Composition W-5> Wax composition W-5 was obtained in the same manner as in Synthesis Example 1, except that fatty acid FA-3 was used instead of fatty acid FA-1.

[0051] <Synthesis Example 6: Synthesis of Wax Composition W-6> Wax composition W-6 was obtained in the same manner as in Synthesis Example 1, except that fatty acid FA-4 was used instead of fatty acid FA-1.

[0052] <Synthesis Example 7: Synthesis of Wax Composition W-7> Wax composition W-7 was obtained in the same manner as in Synthesis Example 1, except that fatty acid FA-5 was used instead of fatty acid FA-1.

[0053] <Synthesis Example 8: Synthesis of Wax Composition W-8> Wax composition W-8 was obtained in the same manner as in Synthesis Example 2, except that the amount of fatty acid FA-2 used was changed to 2158.0 g (6.46 mol).

[0054] <Synthesis Example 9: Synthesis of Wax Composition W-9> Wax composition W-9 was obtained in the same manner as in Synthesis Example 2, except that the amount of fatty acid FA-2 used was changed to 2160.3 g (6.46 mol).

[0055] <Synthesis Example 10: Synthesis of Wax Composition W-10> Wax composition W-10 was obtained in the same manner as in Synthesis Example 2, except that the amount of fatty acid FA-2 added was changed to 1924.6 g (5.76 mol).

[0056] <Synthesis Example 11: Synthesis of Wax Composition W-11> Wax composition W-11 was obtained by weighing 100g of wax composition W-9 obtained in synthesis example 9 and 2.1g of fatty acid FA-2 into a glass petri dish and melting and mixing them on a hot plate heated to 120°C.

[0057] <Synthesis Example 12: Synthesis of Wax Composition W-12> Wax composition W-12 was obtained in the same manner as in Synthesis Example 1, except that fatty acid FA-6 was used instead of fatty acid FA-1.

[0058] <Synthesis Example 13: Synthesis of Wax Composition W-13> Wax composition W-13 was obtained in the same manner as in Synthesis Example 1, except that fatty acid FA-7 was used instead of fatty acid FA-1.

[0059] The acid value, hydroxyl value, and melting point were measured for each wax composition. The measurement results are shown in Table 2. The melting point of the wax composition was measured using a differential scanning calorimeter (DSC7000, Hitachi High-Tech Science Co., Ltd.) by the following procedure to determine the temperature of the endothermic peak during melting of the wax composition, which was then defined as the melting point of the wax composition. First, 10 mg of the measurement sample (wax composition) was weighed into an aluminum sample pan. The weighed measurement sample was heated to 200°C at a heating rate of 10°C per minute in a measurement folder into which nitrogen was blown at a flow rate of 60 ml per minute, and then cooled to 30°C at a cooling rate of 2°C per minute to ensure a uniform thermal history of the measurement sample. Subsequently, the measurement sample was heated from 30°C to 200°C at a heating rate of 10°C per minute to obtain a DSC curve during heating. An endothermic peak was observed during this heating. The temperature of this endothermic peak was defined as the melting point of the wax composition. If two or more endothermic peaks were observed, the temperature of the peak showing the largest endothermic amount was defined as the melting point of the wax composition. The measurement results were analyzed using the analysis software included with the DSC7000.

[0060] Furthermore, the structure and content of each component contained in the wax composition were determined by gas chromatography (GC). The total content of tetraester T shown in the above structural formula (I) (T content, unit: mass%), and the tetraester T with the highest content among the tetraester T contained in the wax composition. A Content (T A Table 2 shows the content (unit: mass%), the content of partial esters (unit: mass%), and the content of fatty acid, which is component X (unit: mass%). Note that the "partial esters" shown in Table 2 are partial esters of the raw material fatty acid used in each synthesis example and pentaerythritol.

[0061] The raw material fatty acids FA-1 to FA-7 contained multiple types of straight-chain saturated fatty acids with different numbers of carbon atoms, as shown in Table 1. In the raw material fatty acids shown in Table 1, carbon numbers of 14, 16, 18, 20, 22, 24, 26, 28, and 30 represent the carbon atoms of the straight-chain saturated fatty acids, respectively. Table 1 also shows the mass percentage (mass%) of each straight-chain saturated fatty acid contained in each raw material fatty acid.

[0062] [Table 1]

[0063] [Table 2]

[0064] The wax compositions W-1 to W-8 contained 80 to 98% by mass of tetraester T represented by the above structural formula (I), had an acid value of 2 mg KOH / g or less, a hydroxyl value of 1 mg KOH / g or more and 10 mg KOH / g or less, and a melting point of 75°C or higher, which were the wax compositions of the present invention. On the other hand, wax compositions W-9 to W-13 were not the wax compositions of the present invention in the following respects. The wax composition W-9 contained more than 98% by mass of tetraester T represented by the above structural formula (I), and had a hydroxyl value of less than 1 mgKOH / g. Wax composition W-10 contained less than 80% by mass of tetraester T represented by the above structural formula (I), and its hydroxyl value exceeded 10 mgKOH / g. Wax composition W-11 had an acid value exceeding 2 mg KOH / g. The wax composition W-12 had a melting point of less than 75°C. Wax composition W-13 contained a tetraester of a linear saturated fatty acid having 28 to 30 carbon atoms and pentaerythritol, and did not contain the tetraester T shown in the above structural formula (I). Note that in wax composition W-13 shown in Table 2, the T content refers to the content of the tetraester of a linear saturated fatty acid having 28 to 30 carbon atoms and pentaerythritol, not the content of the tetraester T shown in the above structural formula (I). A The content refers to the content of the tetraester with the highest concentration among the tetraesters of straight-chain saturated fatty acids with 28-30 carbon atoms and pentaerythritol.

[0065] <Examples 1-16 and Comparative Examples 1-5: Preparation of Model Samples> The wax composition and base oil were mixed to the formulations shown in Table 3. The resulting mixture was melted and mixed at 100°C on a hot plate in an aluminum pan, and then allowed to cool at room temperature for 30 minutes to obtain model samples O-1 to O-21 of oil-based solid cosmetic composition. Note that "Pearlream EX" shown in Table 3 is hydrogenated polyisobutene (product name: Pearlream® EX) manufactured by NOF Corporation. "Panasate 810S" is medium-chain triglyceride (product name: Panasete® 810S) manufactured by NOF Corporation. "Cetiol SN-1" is cetyl ethylhexanoate (product name: Cetiol® SN-1) manufactured by BASF.

[0066] [Evaluation of storage stability under low temperature and low humidity conditions] For the obtained model samples, the gloss value was measured in 10 areas using a HORIBA IG-320 gloss checker under normal temperature and humidity conditions of 25°C and 50% relative humidity, with an incident angle of 60°C. The average value was then defined as the gloss value G. A That's what I decided. Subsequently, the model samples were left standing for one week in a low-temperature, low-humidity environment at 0°C and 40% relative humidity, and then returned to room temperature (25°C, 50% relative humidity). The average gloss value of the model samples at this time was calculated using the same method as above, and the gloss value G was calculated. L That's what I decided. The gloss value G can be calculated using the following formula (3). A and gloss value G L The absolute value of the difference ΔG L Based on this, the storage stability under low temperature and low humidity conditions was evaluated using the following evaluation criteria: ΔG L A smaller value indicates less change in appearance after storage in a low-temperature, low-humidity environment, and is considered to have superior storage stability in such conditions. ΔG L =|G L -G A (3) <Evaluation Criteria> (Excellent storage stability in low-temperature, low-humidity environments) ◎: 1.0≧ΔG L (Excellent storage stability in low-temperature, low-humidity environments) 〇: 2.0 ≥ ΔG L >1.0 (Poor storage stability in low-temperature, low-humidity environments) ×:ΔG L >2.0

[0067] [Evaluation of storage stability under high temperature and high humidity conditions] Similar to the evaluation of storage stability under low temperature and low humidity conditions described above, the gloss value G A The gloss value was measured. Subsequently, the model sample was left to stand for one week in a high-temperature, high-humidity environment of 40°C and 80% relative humidity, and then returned to room temperature (normal temperature and humidity environment of 25°C and 50% relative humidity). The average gloss value of the model sample was then calculated using the same method as above, and the gloss value G was determined. H That's what I decided. The gloss value G is calculated using the following formula (4). A and G H The absolute value of the difference ΔG H Based on this, the storage stability under high temperature and high humidity conditions was evaluated using the following evaluation criteria: ΔG H A smaller value indicates less change in appearance after storage in a high-temperature, high-humidity environment, and is considered to have superior storage stability in such conditions. ΔG H =|G H -G A (4) <Evaluation Criteria> (Excellent storage stability under high temperature and high humidity conditions) ◎: 1.0≧ΔG H (Excellent storage stability under high temperature and high humidity conditions) 〇: 2.0 ≥ ΔG H >1.0 (Poor storage stability in high temperature and high humidity environments) ×:ΔG H >2.0

[0068] [Evaluation of water-washability] A panel of 20 experts evaluated the washability of model samples applied to skin. Specifically, each panelist spread 1g of the model sample on the skin of their inner arm, then rinsed the area with tap water, and evaluated the feel of the skin after rinsing and drying, assigning a score of 1 to 3 based on the following criteria. (standard) 3 points: Easy to rinse off, and leaves skin feeling refreshed after rinsing. Points 2: It's easy to rinse off, but it leaves a slightly oily feeling on the skin after rinsing. 1 point: Difficult to wash off with water, leaves a greasy, sticky feeling on the skin, and lingers a strong oily sensation.

[0069] Furthermore, using the average score of all panelists' ratings, the washability of the model sample was evaluated according to the following criteria. <Judgment criteria> (Judgment): (Average score) ◎: 2.6 or higher ○: 2.0 or higher and less than 2.6 ×: Less than 2.0

[0070] [Table 3]

[0071] Model samples O-17 to O-21 containing wax compositions W-9 to W-13, which are not wax compositions of the present invention, did not exhibit good storage stability under low temperature and low humidity conditions, nor under high temperature and high humidity conditions, at least one of the following. Furthermore, model samples O-17 to O-19 and O-21 containing wax compositions W-9 to W-11 or W-13 had insufficient water washability. In contrast, model samples O-1 to O-16 containing the wax compositions W-1 to W-8 of the present invention exhibited excellent storage stability in both low-temperature, low-humidity environments and high-temperature, high-humidity environments. Therefore, by using the wax compositions W-1 to W-8 of the present invention, the deterioration of storage stability of cosmetics could be suppressed in both low-temperature, low-humidity and high-temperature, high-humidity environments, thereby improving the storage stability of cosmetics. Furthermore, model samples O-1 to O-16 containing the wax compositions W-1 to W-8 of the present invention also exhibited excellent washability. Therefore, by using the wax compositions W-1 to W-8 of the present invention, cosmetics could be made easily washable.

Claims

1. This is a cosmetic wax composition containing an ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol. The ester contains a tetraester T represented by the following structural formula (I), and the content of the tetraester T in the wax composition is 80 to 98% by mass. The wax composition is a cosmetic wax composition having an acid value of 2 mg KOH / g or less, a hydroxyl value of 1 mg KOH / g or more and 10 mg KOH / g or less, and a melting point of 75°C or higher. 【Chemistry 1】 [In structural formula (I), R １ CO, R ２ CO, R ３ CO and R ４ CO independently represents a straight-chain saturated acyl group with 14 to 26 carbon atoms.

2. The ester further contains a partial ester of a linear saturated fatty acid having 14 to 26 carbon atoms and pentaerythritol, and the content of the partial ester in the wax composition is 2 to 20% by mass. The cosmetic wax composition according to claim 1, wherein the linear saturated fatty acid having 14 to 26 carbon atoms contains linear saturated fatty acids having 18 to 22 carbon atoms in a proportion of 90% by mass or more.

3. A method for improving the storage stability of a cosmetic composition and making the cosmetic composition easily washable, wherein the wax composition is the cosmetic wax composition described in claim 1 or 2, in a cosmetic composition containing an oil and a wax.

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