cellulose derivatives

Abstract

To provide a cellulose derivative that can selectively make gel fatty acid in sebum and fatty acid-containing oil such as sebum.SOLUTION: A cellulose derivative comprises a cellulose ether comprising hydroxy groups, of which 5 mol% or more and 29 mol% or less are substituted with -O-M-R1 (M is a methylene group or a carbonyl group, and R1 is a C5-40 linear or branched alkyl group or alkenyl group).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cellulose derivative. [Background technology]

[0002] Cellulose derivatives are used as thickeners and the like in cosmetic compositions and topical skin preparations. Cellulose derivatives into which hydrophobic groups have been introduced are known for the purpose of improving solubility in oil, etc. For example, Patent Document 1 discloses, as an oil-soluble polysaccharide useful as a thickener for cosmetics, a polysaccharide stearate ester or a polysaccharide palmitate ester, in which the polysaccharide is selected from the group consisting of hydroxypropyl cellulose, methylhydroxypropyl cellulose, carboxymethylhydroxypropyl cellulose, hydroxypropyl guar, and hydroxypropyl starch.

[0003] Patent Document 2 discloses that a cellulose derivative in which 67 mol% or more of the total hydroxyl groups of the raw material cellulose derivative are substituted with the group -OCOR (R represents a linear or branched alkyl or alkenyl group having 4 to 40 carbon atoms) and which has a weight-average molecular weight within a specified range, gives a smooth, oily feel without stringiness when dissolved in a hydrophobic oil. Patent Document 3 discloses that an oil-based cosmetic composition containing a cellulose derivative having a cellulose skeleton in the main chain and in which 45 to 65 mol% of all hydroxyl groups are substituted with the group -OMR (where M represents CH2 or a carbonyl group C=O, and R represents a linear or branched alkyl or alkenyl group having 3 to 40 carbon atoms), a volatile hydrocarbon oil, a solid wax, and an ester oil, each in a specified range, breaks down smoothly when applied to the lips, spreads lightly, evenly, and without unevenness, and can be applied neatly along the corners and contours of the lips. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-255401 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-59408 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-224221 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, it has been known that among the components in sebum, unsaturated fatty acids such as oleic acid and palmitoleic acid are factors that cause mild inflammation, rough skin, noticeable irregularities such as pores, and makeup breakdown. Skin irritation caused by fatty acids in sebum is also a problem that causes uneven redness of the skin. More specifically, it is thought that when sebum comes out of pores and spreads over the surface of the skin, and then penetrates the stratum corneum, the oleic acid in the sebum irritates the skin, causing inflammation and resulting in uneven redness.

[0006] It is believed that uneven redness of the skin can be reduced by incorporating a scavenger capable of capturing fatty acids such as oleic acid in sebum into a cosmetic composition. Examples of such scavenger include gelling agents that react with fatty acids to form a gel. An example of a component (gelling agent) that can capture sebum is an oil-absorbing agent, and it is known that oil-absorbing agents are incorporated into cosmetics such as foundations. However, if an oil-absorbing agent has the ability to gel not only fatty acids but also other oil components, there is a problem in that it also gels the oil components incorporated into oil-based cosmetics.

[0007] An object of the present invention is to provide a cellulose derivative capable of selectively gelling fatty acids in sebum and fatty acid-containing oils such as sebum. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by using a cellulose derivative in which the hydroxy groups in a cellulose ether are substituted with predetermined hydrophobic substituents in a specific ratio. That is, the present invention relates to the following. [1] 5 mol% to 29 mol% of the hydroxyl groups in the cellulose ether are -OMR 1 (M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms. [2] A gelling agent for fatty acid-containing oils, containing the cellulose derivative of [1] above. [3] A sebum gelling agent containing the cellulose derivative of [1] above. [4] A skin external preparation composition containing the cellulose derivative of [1] above. [5] 5 mol% to 29 mol% of the hydroxyl groups in the cellulose ether are -OMR 1 (M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms.) Use of a cellulose derivative substituted with such a group as a sebum gelling agent. [Effects of the Invention]

[0009] The cellulose derivative of the present invention is useful as a gelling agent for fatty acids and fatty acid-containing oils. Because the cellulose derivative can selectively gel fatty acids and fatty acid-containing oils, it can be incorporated into, for example, topical skin preparation compositions containing oily ingredients other than fatty acids. When the topical skin preparation composition is applied to the skin, the gelling ability of the fatty acids and fatty acid-containing oils is expected to reduce uneven redness and other skin problems caused by oleic acid and other components in sebum. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Cellulose derivatives] In the cellulose derivative of the present invention, 5 mol % to 29 mol % of the hydroxy groups in the cellulose ether are -OMR 1(M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms. The cellulose derivative of the present invention has the above-mentioned constitution, and is therefore capable of selectively gelling fatty acids in sebum and fatty acid-containing oils such as sebum.

[0011] The reason why the cellulose derivative of the present invention exhibits the above-mentioned effects is not clear, but is thought to be as follows. As mentioned above, conventional oil-absorbing agents that have gelling properties not only for fatty acids but also for other oil components have the problem that when blended into oil-based cosmetics, they also gel oil components other than fatty acids. Therefore, the present inventors focused on cellulose ether as a gelling agent for fatty acids and fatty acid-containing oils (for example, sebum containing oleic acid). Cellulose ether is a compound in which at least some of the hydroxyl groups of cellulose are replaced with ether groups, and is more hydrophobic and has a higher affinity with oils than cellulose.Cellulose ether usually contains residual hydroxyl groups derived from cellulose, and among cellulose ethers, hydroxyalkyl cellulose obtained by reacting cellulose with ethylene oxide, propylene oxide, etc. has a hydroxyl group at the end of the alkyl ether group.The hydroxyl groups remaining in the cellulose ether and the carboxyl groups in the fatty acid are thought to form hydrogen bonds, thereby producing the effect of gelling the fatty acid.

[0012] Here, according to the findings of the present inventors, it has been found that cellulose ethers are likely to exhibit the gelling ability of fatty acids when fatty acids are present alone, but are unlikely to exhibit the gelling ability when used with oils containing fatty acids. The reason for this is thought to be as follows: Human sebum, a type of fatty acid-containing oil, is known to contain triacylglycerol (TAG), squalene, etc. in addition to fatty acids. It is presumed that because fatty acids are incorporated into other more hydrophobic oils (TAG and squalene), it becomes difficult for the highly hydrophilic cellulose ether and fatty acids to come into contact with each other in the sebum, resulting in a decrease in the fatty acid capture effect. On the other hand, cellulose derivatives having many hydrophobic groups introduced therein as described in the above patent documents have improved affinity with highly hydrophobic oils. However, the cellulose derivatives do not have a sufficient number of hydroxy groups to capture fatty acids, and the solubility in oils other than fatty acids is excessively high, which is thought to make it difficult for the gelling ability of fatty acids and fatty acid-containing oils to be expressed. In the cellulose derivative of the present invention, a specific amount of the hydroxy groups in the cellulose ether is converted into hydrophobic groups (-OMR 1 ), it is believed that by using a cellulose derivative substituted with hydroxyl groups, it is possible to enhance the effect of capturing fatty acids incorporated into other oil agents while retaining a sufficient number of hydroxyl groups for the carboxyl groups in the fatty acids to form hydrogen bonds, and to selectively gel fatty acids and fatty acid-containing oils. However, the mechanism of action of the present invention is not limited to the above.

[0013] <Cellulose ether> In the cellulose derivative of the present invention, 5 mol % to 29 mol % of the hydroxy groups in the cellulose ether are -OMR 1 (M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms. From the viewpoint of the gelling ability of the fatty acids and fatty acid-containing oils of the resulting cellulose derivative, the cellulose ether (hereinafter also referred to as "raw cellulose ether") is preferably at least one selected from the group consisting of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, glyceryl cellulose, and methylglyceryl cellulose.

[0014] From the viewpoints of ease of introduction of hydrophobic substituents, gelling ability of the fatty acids and fatty acid-containing oils of the resulting cellulose derivative, and stability when incorporated into topical skin compositions, etc., the starting cellulose ether more preferably has a constituent unit represented by the following general formula (1): [ka] (In the formula, R 2 represents a linear or branched alkylene group having 2 to 10 carbon atoms. n represents R 2 R denotes the average number of moles of O added per glucose unit 2 The average number of moles of O added is 0.5 or more and 5.0 or less. 2 and n may all be the same or different.

[0015] In general formula (1), R 2 is preferably a linear or branched alkylene group having 2 to 4 carbon atoms, more preferably an ethylene group or a propylene group, and even more preferably a propylene group. 2 The average number of moles of O added is the total number of three n's in the glucose unit represented by general formula (1), and is 0.5 or more, preferably 1.0 or more, more preferably 2.0 or more, and even more preferably 2.5 or more, and is 5.0 or less, preferably 4.5 or less, and more preferably 4.0 or less. R in raw cellulose ether 2The average number of moles of O added can be determined by the Zeisel method [see Analytical Chemistry, Vol. 51, No. 13, 2172 (1979), "The Japanese Pharmacopoeia, 15th Edition (section on analytical methods for hydroxypropyl cellulose)"].

[0016] The preferred starting cellulose ether is at least one selected from the group consisting of hydroxyethyl cellulose and hydroxypropyl cellulose, more preferably hydroxypropyl cellulose, from the viewpoints of ease of introduction of hydrophobic substituents, gelling ability of the fatty acids and fatty acid-containing oils of the resulting cellulose derivative, and stability when incorporated into topical skin preparation compositions and the like.

[0017] The weight-average molecular weight (Mw) of the starting cellulose ether is preferably 40,000 or more, more preferably 50,000 or more, even more preferably 100,000 or more, and even more preferably 300,000 or more, from the viewpoint of gelling ability of fatty acids and fatty acid-containing oils. From the viewpoint of stability when incorporated into external skin preparation compositions and the like, the weight-average molecular weight (Mw) is preferably 2,500,000 or less, more preferably 2,000,000 or less, even more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. The weight-average molecular weight (Mw) of the raw cellulose ether is measured by gel permeation chromatography (GPC) using water, alcohol, chloroform, dimethylformaldehyde, tetrahydrofuran, acetonitrile, or a combination of these solvents as the eluent, and is expressed as the molecular weight in terms of polystyrene.

[0018] The starting cellulose ether can be produced by a known method. For example, hydroxypropyl cellulose can be produced by adding propylene oxide to alkali cellulose activated by alkali cellulose ether. More specifically, cellulose is mixed in a slurry state with a large amount of water and a large excess of an alkali metal hydroxide such as sodium hydroxide to produce alkali cellulose, which is an activation treatment called alkali cellulose ether or mercerization, and then the alkali cellulose is reacted with propylene oxide to produce hydroxypropyl cellulose.

[0019] Commercially available cellulose ethers can also be used as the raw material. Among cellulose ethers, commercially available hydroxypropyl cellulose products include "HPC-SSL," "HPC-SL," "HPC-L," "HPC-M," "HPC-H," and "HPC-VH" manufactured by Nippon Soda Co., Ltd., and "KLUCEL MF Pharm" and "KLUCEL HPC" manufactured by Ashland Pharmaceuticals.

[0020] (Hydrophobic Substituent - OMR 1 ) In the cellulose derivative of the present invention, 5 mol % to 29 mol % of the hydroxy groups in the raw material cellulose ether are -OMR 1 (M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms. From the viewpoint of improving the gelling ability of fatty acids and fatty acid-containing oils and from the viewpoint of ease of production, the hydrophobic substituent -OMR 1 In this, M is preferably a carbonyl group. The above hydrophobic substituent -OMR 1 R in 1 The number of carbon atoms in the group is preferably 7 or more, more preferably 11 or more, and even more preferably 13 or more, from the viewpoint of improving the gelling ability of fatty acids and fatty acid-containing oils, and is preferably 30 or less, more preferably 23 or less, even more preferably 21 or less, and even more preferably 17 or less, from the viewpoint of suppressing excessive improvement in solubility in oils other than fatty acids and fatty acid-containing oils.

[0021] R 1 In the formula (I), examples of the straight-chain alkyl group include an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-icosyl group, an n-henicosyl group, an n-docosyl group, an n-tricosyl group, an n-tetracosyl group, an n- Examples include a pentacosyl group, an n-hexacosyl group, an n-heptacosyl group, an n-octacosyl group, an n-nonacosyl group, a triacontyl group, an n-hentriacontyl group, an n-dotriacontyl group, an n-tritriacontyl group, an n-tetratriacontyl group, an n-pentatriacontyl group, an n-hexatriacontyl group, an n-heptatriacontyl group, an n-octatriacontyl group, an n-nonatriacontyl group, and an n-tetracontyl group.

[0022] R 1 Examples of the branched alkyl group in the formula (I) include a methylpentyl group, a methylhexyl group, a methylheptyl group, a 2-ethylhexyl group, a methyloctyl group, a methylnonyl group, a methylundecyl group, a methylheptadecyl group, an ethylhexadecyl group, a methyloctadecyl group, a propylpentadecyl group, a 2-hexyldecyl group, a 2-octyldodecyl group, a 2-heptylundecyl group, a 2-decyltetradecyl group, a 2-dodecylhexadecyl group, a 2-tetradecyloctadecyl group, and a 2-hexadecylicosyl group.

[0023] R 1 Examples of the linear alkenyl group in the formula (I) include a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an icosenyl group, a henicosenyl group, a docosenyl group, a tricosenyl group, a tetracosenyl group, a pentacosenyl group, a hexacosenyl group, a heptacosenyl group, and an octacosenyl group. Also R1 Examples of the branched alkenyl group in the formula (I) include an isopentenyl group, an isohexenyl group, an isoheptenyl group, an isooctenyl group, an isononenyl group, an isodecenyl group, an isoundecenyl group, an isododecenyl group, an isotridecenyl group, an isooctadecenyl group, an isotriacontenyl group, a 2-butyloctenyl group, a 2-hexyldecenyl group, a 2-octyldodecenyl group, a 2-decyltetradecenyl group, and a 2-dodecylhexadecenyl group.

[0024] Among the above, from the viewpoint of improving the gelling ability of fatty acids and fatty acid-containing oils and from the viewpoint of ease of production, R 1 is preferably a linear alkyl group having 5 to 40 carbon atoms, more preferably a linear alkyl group having 7 to 23 carbon atoms, even more preferably a linear alkyl group having 7 to 21 carbon atoms, still more preferably a linear alkyl group having 11 to 17 carbon atoms, even more preferably a linear alkyl group having 13 to 17 carbon atoms, still more preferably one or more selected from the group consisting of an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, and an n-heptadecyl group, even more preferably one or more selected from the group consisting of an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, and an n-heptadecyl group, and still more preferably an n-pentadecyl group.

[0025] Specific examples of the cellulose derivative of the present invention include fatty acid esters of hydroxyalkyl cellulose, such as hydroxyethyl cellulose laurate, hydroxyethyl cellulose myristate, hydroxyethyl cellulose palmitate, hydroxyethyl cellulose stearate, hydroxyethyl cellulose behenate, hydroxypropyl cellulose laurate, hydroxypropyl cellulose myristate, hydroxypropyl cellulose palmitate, hydroxypropyl cellulose stearate, hydroxypropyl cellulose behenate, hydroxyethyl methylcellulose laurate, hydroxyethyl methylcellulose myristate, hydroxyethyl methylcellulose palmitate, hydroxyethyl methylcellulose stearate, hydroxyethyl methylcellulose behenate, hydroxypropyl methylcellulose laurate, hydroxypropyl methylcellulose myristate, hydroxypropyl methylcellulose palmitate, hydroxypropyl methylcellulose stearate, and hydroxypropyl methylcellulose behenate. Among the above, from the viewpoint of the gelling ability of fatty acids and fatty acid-containing oils, fatty acid esters of hydroxypropyl cellulose are preferred, and one or more selected from the group consisting of hydroxypropyl cellulose laurate, hydroxypropyl cellulose myristate, hydroxypropyl cellulose palmitate, hydroxypropyl cellulose stearate, and hydroxypropyl cellulose behenate are more preferred, with hydroxypropyl cellulose palmitate being even more preferred.

[0026] The weight-average molecular weight (Mw) of the cellulose derivative is preferably 40,000 or more, more preferably 50,000 or more, even more preferably 100,000 or more, and even more preferably 300,000 or more, from the viewpoint of the gelling ability of fatty acids and fatty acid-containing oils. Also, from the viewpoint of stability when incorporated into external skin preparation compositions, etc., it is preferably 2,500,000 or less, more preferably 2,000,000 or less, even more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. The weight average molecular weight (Mw) of the cellulose derivative can be measured by gel permeation chromatography (GPC) in the same manner as the Mw of the cellulose ether.

[0027] In cellulose derivatives, the hydrophobic substituent of the hydroxy group in the cellulose ether - OMR 1 The degree of substitution with (hereinafter also referred to as "amount of hydrophobic substituent introduced") is 5 mol% or more, more preferably 7 mol% or more, from the viewpoint of improving the gelling ability of fatty acids and fatty acid-containing oils. Also, from the viewpoint of suppressing excessive improvement in solubility in oils other than fatty acids and fatty acid-containing oils, it is 29 mol% or less, preferably 25 mol% or less, more preferably 20 mol% or less, and even more preferably 18 mol% or less. The amount of the hydrophobic substituent introduced was measured by nuclear magnetic resonance spectroscopy ( 1 It can be determined by calculating the ratio of the number of moles of hydrophobic substituents in the cellulose derivative to the number of moles of hydroxy groups in the cellulose derivative before the introduction of the hydrophobic substituents, using a H-NMR method. 1 When M is a carbonyl group, the amount of the hydrophobic substituent introduced can be measured by the method described in the Examples.

[0028] In addition, hydrophobic substituents of cellulose derivatives -OMR 1 When M is a carbonyl group, from the viewpoint of improving the gelling ability of fatty acids and fatty acid-containing oils, the absorption (1735 cm) corresponding to the ester group in the hydrophobic substituent in the cellulose derivative measured by infrared spectroscopy (IR) is -1The area (P1) of the absorption band corresponding to the hydroxyl group in the cellulose derivative (3450 cm -1 The ratio (P1 / P2) of the area (P1) of the surface area (P2) of the oil agent (near the surface area) to the area (P1 / P2) of the surface area (P1) of the oil agent (near the surface area ... The above ratio (hereinafter also referred to as "-COO- / -OH") can be specifically measured by the method described in the Examples.

[0029] The cellulose derivatives contain a hydrophobic substituent -OMR 1 The compound in which M is a carbonyl group can be produced by reacting a raw material cellulose ether with an acid halide having a linear or branched alkyl or alkenyl group having 5 to 40 carbon atoms. Examples of acid halides include fatty acid chloride, fatty acid bromide, fatty acid fluoride, and fatty acid iodide, with fatty acid chloride being preferred. These can be used alone or in combination of two or more. The amount of acid halide used is preferably 0.05 mol or more, more preferably 0.08 mol or more, per mol of hydroxyl groups in the raw cellulose ether. On the other hand, from the viewpoint of production cost, it is preferably 1.0 mol or less, more preferably 0.5 mol or less.

[0030] The reaction between the starting cellulose ether and the acid halide is preferably carried out in a basic solvent, which can act as a solvent and also make the solution basic. The basic solvent is a solvent that accepts protons, such as morpholine, acetylmorpholine, pyridine, 3-methylpyridine, 4-dimethylaminopyridine, N-methyl-2-pyrrolidone, α-picoline, β-picoline, γ-picoline, 2,4-lutidine, 2,6-lutidine, piperidine, pyrrolidine, quinoline, isoquinoline, etc., which can be used alone or in combination of two or more. The amount of the basic solvent used is preferably 1.0 mole or more, more preferably 1.5 moles or more, per mole of the acid halide from the viewpoint of reactivity, while it is preferably 10 moles or less from the viewpoint of production costs.

[0031] In addition, organic solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, dipropyl sulfoxide, dipropyl sulfoxide, methyl ethyl ketone, tetrahydrofuran, chloroform, dichloromethane, dichloroethane, toluene, xylene, hexaneheptane, etc. may be further added as needed within the range that does not impair the reactivity of the hydroxy groups of the starting cellulose ether with the acid halide. These may be used alone or in combination of two or more.

[0032] From the viewpoint of improving the acylation rate, the above reaction is preferably carried out in a homogeneous system in which the raw cellulose ether is dissolved in a solvent. From the viewpoint of improving the reaction efficiency, the concentration of the raw cellulose ether in the reaction solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1.0% by mass or more. From the viewpoint of improving the acylation rate by carrying out the reaction in a homogeneous system, the concentration is preferably 6% by mass or less, more preferably 5% by mass or less.

[0033] From the viewpoints of the thermal stability of the starting cellulose ether and the reactivity of the acid halide, the reaction temperature is preferably 0 to 150° C., more preferably 30 to 120° C. The reaction time is not particularly limited, but from the viewpoints of reactivity and production efficiency, it is preferably 0.5 to 30 hours. After the reaction is completed, the resulting reaction solution is poured into a non-polar organic solvent such as hexane to reprecipitate the cellulose derivative, which can then be purified by drying.

[0034] Alternatively, hydrophobic substituent -OMR 1 The cellulose derivative in which M is a carbonyl group can also be produced by transesterification (acidolysis) of acetyl cellulose.

[0035] In addition, hydrophobic substituent -OMR 1 Those in which M is a methylene group can be produced by reacting a starting cellulose ether with the corresponding alkyl halide or alkenyl halide, or a sulfonic acid ester such as alkyl mesylate, in the presence of a base.

[0036] [Gelling agent] The present invention also provides a gelling agent for fatty acid-containing oil containing the cellulose derivative of the present invention, and a sebum gelling agent containing the cellulose derivative of the present invention. Hereinafter, these are collectively referred to as "the gelling agent (of the present invention)." The gelling agent of the present invention contains the cellulose derivative, which allows it to selectively gel fatty acids and fatty acid-containing oils. Therefore, when the gelling agent of the present invention is incorporated into, for example, an oil-based cosmetic, it does not gel oils other than fatty acids, and when the topical skin preparation composition is applied to the skin, it has the effect of capturing and gelling oleic acid and sebum, a type of fatty acid-containing oil.

[0037] From the viewpoint of the gelling ability of fatty acid-containing oils, the content of the cellulose derivative in the gelling agent is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, and is 100% by mass or less.

[0038] Fatty acids in fatty acid-containing oils to be gelled by a gelling agent include saturated or unsaturated fatty acids having from 8 to 24 carbon atoms, such as one or more selected from the group consisting of 2-ethylhexanoic acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, margadelic acid, stearic acid, oleic acid, and linoleic acid. Oleic acid is preferred from the viewpoint of being a fatty acid contained in sebum. The content of fatty acids in the fatty acid-containing oil is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of more effectively exhibiting gelling ability. The upper limit may be 100% by mass, and even if the content is, for example, 80% by mass or less, preferably 60% by mass or less, the gelling ability can be effectively exhibited.

[0039] From the viewpoint of more effectively exhibiting the gelling ability of the cellulose derivative of the present invention, the acid value of the fatty acid-containing oil is preferably 0.1 mgKOH / g or more, more preferably 1 mgKOH / g or more, even more preferably 10 mgKOH / g or more, and even more preferably 40 mgKOH / g or more. There is no particular upper limit to the acid value of the fatty acid-containing oil, but it is usually 300 mgKOH / g or less.

[0040] The fatty acid-containing oil to be gelled by the gelling agent may be any of mineral oil, natural oil, synthetic oil, etc. Specific examples of fatty acid-containing oils include industrial lubricating oils such as cutting oil, hydraulic oil, bearing oil, rolling oil, gear oil, rust preventative oil, drawn oil, drawing oil, vacuum pump oil, etc.; oils for transport machinery such as automobiles and ships, such as engine oil and transmission oil; and secreted oils such as sebum. From the viewpoint of use in a skin external preparation composition, the fatty acid-containing oil is more preferably sebum.

[0041] [External skin preparation composition] The present invention provides a skin topical preparation composition containing the cellulose derivative of the present invention. The skin topical preparation composition is preferably a skin cosmetic composition, from the viewpoint of effectively exerting the gelling ability of the fatty acid and the fatty acid-containing oil. Examples of the skin cosmetic composition include makeup cosmetics, sunscreen cosmetics, makeup bases, emulsions, serums, and creams.

[0042] The formulation of the topical skin composition is not particularly limited, and can be any formulation, such as liquid, foam, paste, cream, solid, etc. From the viewpoint of preventing the oil in the formulation from gelling and selectively gelling oleic acid and sebum, a type of fatty acid-containing oil, when applied to the skin, the formulation of the topical skin composition is more preferably liquid. Here, "liquid" refers to a composition that has fluidity at room temperature (25°C).

[0043] The content of the cellulose derivative in the topical skin preparation composition is not particularly limited, but from the viewpoint of effectively exerting the gelling ability of the fatty acid and fatty acid-containing oil, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, and from the viewpoint of economy, it is preferably 40% by mass or less, more preferably 30% by mass or less.

[0044] [Use as a sebum gelling agent] The present invention relates to a cellulose ether in which 5 mol % or more and 29 mol % or less of the hydroxy groups are -OMR. 1 (M represents a methylene group or a carbonyl group, and R 1 represents a linear or branched alkyl or alkenyl group having from 5 to 40 carbon atoms.) is used as a sebum gelling agent. The cellulose derivative and preferred embodiments thereof are the same as those described above. The cellulose derivative of the present invention is capable of selectively gelling fatty acids and fatty acid-containing oils. Therefore, for example, when the cellulose derivative is used as a sebum gelling agent in an external skin preparation composition and applied to the skin, oleic acid and sebum containing oleic acid are selectively captured on the skin, and the effect of reducing uneven redness of the skin caused by oleic acid can be expected. [Example]

[0045] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples. In the examples, various measurements and evaluations were carried out by the following methods.

[0046] <Measurement of the amount of hydrophobic substituents introduced into cellulose derivatives> A measurement sample was prepared by dissolving each example of cellulose derivative (Xg) and an internal standard (tetramethylsilane) in deuterated chloroform. 1 H-NMR measurements were performed. The molar number (A mol) of the hydrophobic substituent in the cellulose derivative contained in the measurement sample was calculated from the ratio of the mass of the cellulose derivative contained in the measurement sample and the integral value of the proton signal derived from the ester group in the hydrophobic substituent at approximately 2.25 ppm to the mass of the internal standard and the integral value of the proton signal derived from the internal standard at approximately 0 ppm. Furthermore, the mass (Y g) of the hydrophobic substituent in the cellulose derivative contained in the measurement sample was calculated from this value. The mass of the cellulose derivative contained in the measurement sample, converted into cellulose before the introduction of the hydrophobic substituent (i.e., raw cellulose ether), is (XY) g, and the number of moles is (XY) / W mol, where W is the molecular weight of the raw cellulose ether. The molar ratio of the ester group in the hydrophobic substituent in the cellulose derivative to the hydroxy group in the cellulose derivative (hydroxypropyl cellulose in this example) before the introduction of the hydrophobic substituent was calculated using the following formula, and this value was taken as the amount of hydrophobic substituent introduced. Amount of hydrophobic substituent introduced (mol%) = number of moles of ester groups in cellulose derivative / number of moles of hydroxyl groups in raw cellulose ether × 100 = A / [(XY) / W × 3] × 100

[0047] <-COO- / -OH> Using an infrared spectrophotometer "Nicolet iS5 (iD7 ATR)" manufactured by Thermo Fisher Scientific Co., Ltd., infrared spectroscopic analysis (IR) was performed by the ATR method using the cellulose derivatives of each example as samples. In the IR measurement chart, the vertical axis represents Abs and the horizontal axis represents wavenumber (cm -1 ) and the absorption (1735 cm ) corresponding to the ester group in the hydrophobic substituent in the cellulose derivative. -1 The area (P1) of the absorption band corresponding to the hydroxyl group in the cellulose derivative (3450 cm -1 The ratio (P1 / P2) of the area of ​​the area surrounding the nucleus (P1) to the area of ​​the area surrounding the nucleus (P2) was calculated, and this value was taken as the -COO- / -OH value.

[0048] <Evaluation of insolubility in triacylglycerol (TAG)> 1 g of the cellulose derivative of each example was weighed into a glass container, and 10 g of TAG (Crupure OL (olive fruit oil) manufactured by Croda Japan Co., Ltd.) was added. After leaving it at room temperature (25°C) for 6 hours, the state was visually observed and evaluated according to the following criteria. 5: Insoluble 4: Insoluble (swelling) 3: Uniform dispersion 2: Partial dissolution 1: Completely dissolved

[0049] <Evaluation of insolubility in squalene> 1 g of the cellulose derivative of each example was weighed into a glass container, and 10 g of squalene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. After leaving it at room temperature (25°C) for 6 hours, the state was visually observed and evaluated according to the following criteria. 5: Insoluble 4: Insoluble (swelling) 3: Uniform dispersion 2: Partial dissolution 1: Completely dissolved

[0050] <Gelling ability of oleic acid> 1 g of the cellulose derivative of each example was weighed into a glass container, and 10 g of oleic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. After leaving it at room temperature (25°C) for 6 hours, the state was visually observed and evaluated according to the following criteria. 5: Gelation 4:High viscosity 3:Dissolution 2: Slightly soluble 1: Insoluble

[0051] <Gelling ability of artificial sebum> 1 g of the cellulose derivative of each example was weighed into a glass container, and 10 g of artificial sebum (TAG / squalene / oleic acid = 3 / 3 / 2 (mass ratio)) was added. After leaving it at room temperature (25°C) for 6 hours, the condition was visually observed and evaluated according to the following criteria. 5: Gelation 4:High viscosity 3:Dissolution 2: Slightly soluble 1: Insoluble

[0052] Example 1 (Production and Evaluation of Cellulose Derivative 1) Under a nitrogen stream, 100 g (0.283 mol) of the starting cellulose ether, hydroxypropyl cellulose (HPC-M, manufactured by Nippon Soda Co., Ltd., PO molar substitution: 3.3) and 105 g (1.13 mol) of 3-methylpyridine were dissolved in 2200 mL of a toluene-methyl ethyl ketone mixed solvent at 50°C. 61.7 g (0.22 mol) of palmitoyl chloride was added dropwise over 0.5 hours, and the mixture was allowed to react at 60°C for 5 hours. The resulting reaction product was precipitated in n-hexane for purification, and the precipitate was then dried to obtain a cellulose derivative (hydroxypropyl cellulose palmitate). The obtained cellulose derivative was evaluated by the above-mentioned method, and the results are shown in Table 1.

[0053] Example 2 (Production and Evaluation of Cellulose Derivative 2) Hydroxypropyl cellulose palmitate was produced in the same manner as in Example 1, except that the amount of palmitoyl chloride added was changed to 34.2 g (0.12 mol), and evaluated by the above-mentioned method. The results are shown in Table 1.

[0054] Example 3 (Production and Evaluation of Cellulose Derivative 3) Hydroxypropyl cellulose palmitate was produced in the same manner as in Example 1, except that the amount of palmitoyl chloride added was changed to 74.7 g (0.27 mol), and evaluated by the above-mentioned method. The results are shown in Table 1.

[0055] Comparative Example 1 (Production and Evaluation of Comparative Cellulose Derivative 1) Hydroxypropyl cellulose palmitate was produced in the same manner as in Example 1, except that the amount of palmitoyl chloride added was changed to 117.9 g (0.42 mol), and evaluated by the above-mentioned method. The results are shown in Table 1.

[0056] Comparative Example 2 (Production and Evaluation of Comparative Cellulose Derivative 2) Hydroxypropyl cellulose palmitate was produced in the same manner as in Example 1, except that the amount of palmitoyl chloride added was changed to 235.8 g (0.84 mol), and evaluated by the above-mentioned method. The results are shown in Table 1.

[0057] [Table 1]

[0058] As shown in Table 1, the cellulose derivative of this example exhibits gelling ability with both the fatty acid oleic acid and the artificial sebum containing oleic acid. Furthermore, it does not have gelling ability with oils other than fatty acids and fatty acid-containing oils, such as triacylglycerol and squalene, and has low solubility in these oils. In contrast, the cellulose derivatives of Comparative Examples 1 and 2, in which the amount of hydrophobic substituent introduced exceeds the range specified in the present invention, are easily soluble in triacylglycerol and squalene, and their gelling ability with oleic acid and artificial sebum is lower than that of the cellulose derivatives of this example. [Industrial Applicability]

[0059] The cellulose derivative of the present invention is useful as a gelling agent for fatty acids and fatty acid-containing oils. Because the cellulose derivative can selectively gel fatty acids and fatty acid-containing oils, it can be incorporated into, for example, topical skin preparation compositions containing oily ingredients other than fatty acids. When the topical skin preparation composition is applied to the skin, the gelling ability of the fatty acids and fatty acid-containing oils is expected to reduce uneven redness and other skin problems caused by oleic acid and other components in sebum.

Claims

1. The cellulose ether is a cellulose derivative having a constitutional unit represented by the following general formula (1): 7 mol % or more and 20 mol % or less of the hydroxy groups in the cellulose ether are -OM-R １ (M represents a carbonyl group, R １ represents a linear alkyl group having 11 or more and 21 or less carbon atoms. 【Chemistry 1】 (In the formula, R ２ represents a propylene group. n represents R ２ The average number of moles of O added is shown, and R per glucose unit is shown. ２ The average number of moles of O added is 2.0 or more and 4.0 or less. In the formula, the multiple n's may all be the same or different.

2. A gelling agent for fatty acid-containing oils, comprising the cellulose derivative according to claim 1.

3. A sebum gelling agent comprising the cellulose derivative according to claim 1.

4. A skin external preparation composition containing the cellulose derivative according to claim 1.

5. The cellulose ether is a cellulose derivative having a structural unit represented by the following general formula (1), and 7 mol % to 20 mol % of the hydroxy groups in the cellulose ether are -OM-R １ (M represents a carbonyl group, R １ represents a linear alkyl group having 11 to 21 carbon atoms.) Use of a composition containing a cellulose derivative substituted with such a group as a skin cosmetic composition. 【Chemistry 2】 (In the formula, R ２ represents a propylene group. n represents R ２ The average number of moles of O added is shown, and R per glucose unit is shown. ２ The average number of moles of O added is 2.0 or more and 4.0 or less. In the formula, the multiple n's may all be the same or different.

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