JP6836406B2 - Scrub and skin cleansing composition - Google Patents

Description

The present invention relates to scrubbing agents and skin cleansing compositions.

Polysaccharides such as porous cellulose particles and their derivatives have characteristics such as having a large surface area, high mechanical strength, and being able to support various ligands by modifying hydroxyl groups. Conventionally, it has been used for the purpose of fulfilling various functions such as filtration, absorption and adsorption in the fields of cosmetics, pharmaceuticals and foods, and other fields of industrial use.

Previously, cosmetics and industrial abrasives contained fruit seeds such as natural walnuts and apricots and coconut shells as scrubbing agents. However, in recent years, synthetic polymer fine particles such as polyethylene have been made because it is easy to control the particle size from small to large, the surface area can be made very large, and the dispersibility in other substances is good. However, it is used especially in cosmetics and pharmaceuticals.

Among the synthetic polymer fine particles, there are those called microbeads in particular. Microbeads are small spherical beads made of plastic such as polyethylene or polypropylene. The size is about several microns to several hundred microns (0.001 mm to 0.1 mm), but the particle size varies depending on the application. Microbeads are added to cosmetics such as face wash, body wash and toothpaste as a material exhibiting a so-called scrub function for the purpose of removing stains on the skin and old keratin, for example.

Synthetic polymer fine particles, especially polyethylene polymer fine particles, are widely used and are contained in more than 2,000 cosmetic products out of about 30,000. Specifically, for example, facial cleansers such as face wash soap, face wash foam and face wash powder; cleansing agents such as cleansing oil, cleansing gel, cleansing cream and cleansing point remover; skin care beauty liquid emulsion, face cream, face oil, face balm And moisturizing cosmetics such as lip care; special care cosmetics such as cleansing packs, mask sheet packs, mask gommages and peeling massages; eye care cosmetics such as eyelash beauty liquids; hair care shampoos, conditioners, hair packs, hair treatments and Hair or scalp cosmetics such as non-rinse treatments; Body care cosmetics such as body cleansers, body lotions, body milk, body creams, body oils, body scrubs, bust care, hip care, leg care, foot care and hand care; face Examples include sunscreens for the body or for the body.

However, microbeads are small spherical beads made of plastic such as polyethylene or polypropylene, which have a light specific gravity of 1 or less and the particle size is too small, so that they easily float on water and cannot be removed by wastewater treatment facilities. In some cases, it may flow directly into the sea through a river or even a river. Therefore, there is a problem that the ocean and the like are contaminated with plastic microbeads.

Furthermore, since plastic has the property of adsorbing trace amounts of chemical pollutants in the environment, if a plankton or fish swallows microbeads that have adsorbed the chemical pollutants, it may have an adverse effect on the human body. There are concerns that it will have various effects.

Due to these concerns, attempts have been made to replace the fine particles of synthetic polymers used in various applications with biodegradable particles.

Non-Patent Document 1 proposes a biodegradable scrubbing agent manufactured by LESSONIA (France) and used for all cosmetics containing polishing and scrubbing. Further, it is described that the raw material of the scrubbing agent is cellulose acetate, which has the same polishing performance, the same particle size, and the same suspension (dispersion) property as polyethylene beads with the same specific gravity.

Patent Document 1 describes a cosmetic product containing porous spherical cellulose having a particle size of 0.1 to 1.0 mm and a bulk specific gravity of 0.1 to 0.7 g / cc.

Patent Document 2 describes a scrubbing agent composed of non-spherical cellulose particles having a particle size of 0.1 to 1 mm and a bulk specific gravity of 0.08 to 0.7 g / ml.

Patent Document 3 describes a scrubbing agent containing at least one selected from the group consisting of microbially produced cellulose and sweet potato straining residue as an active ingredient.

Japanese Unexamined Patent Publication No. 63-238008 Japanese Unexamined Patent Publication No. 2001-122766 JP-A-2007-091717

"CELLLOSCRUBTM Cellulous Club-Ultimate Polyethylene Bead Replacement, Scrub Agent-", [online], TS Trading Co., Ltd., [Searched October 03, 2016], Internet (URL: http://www.tsti.co. jp / cosmetic / data / 1-3.pdf)

However, the porous spherical cellulose described in Patent Document 1 does not have sufficient porosity. Although the cellulose particles described in Patent Document 2 are irregularly shaped particles, they also do not have sufficient porosity. As a problem to be solved by the scrubbing agent described in Patent Document 3, it is described to provide a scrubbing agent derived from a natural product having excellent water absorption and not requiring a surface treatment. Since it has a fiber shape and is not in the form of particles, it is inferior in usability. Further, cellulose acetate having a general degree of substitution as described in Non-Patent Document 1 is inferior in biodegradability with respect to cellulose.

In addition, the seeds and coconut shells of fruits such as natural walnuts and apricots that have been used for a long time have excellent biodegradability and are environmentally friendly. However, the hardness is high and there is a risk of damaging the skin, the water absorption and oil retention properties are low, and the detergency is not sufficient.

An object of the present invention is to provide a scrubbing agent having sufficient biodegradability and excellent detergency and usability.

The first aspect of the present invention is a scrubbing agent composed of porous cellulose particles, wherein the porous cellulose particles have a cellulose type II crystal structure, a particle size of 100 μm or more and 1,000 μm or less in a median diameter, and a nitrogen method. The specific surface area obtained by the BET specific surface area measurement method is 10 m ² / g or more and 100 m ² / g or less, the bulk specific surface area is 0.38 g / ml or more and 0.55 g / ml or less, and the biodegradability rate is within 10 days. With respect to scrubbing agents, which are at least 50% by weight.

The scrubbing agent preferably has the porous cellulose particles having a median diameter of 100 μm or more and 900 μm or less.

^{The scrubbing agent preferably has a specific surface area of 10 m 2} / g or more and 50 m ² / g or less obtained by the nitrogen method BET specific surface area measurement method of the porous cellulose particles.

The second aspect of the present invention relates to a skin cleansing composition containing the scrubbing agent.

A third aspect of the present invention relates to a facial cleansing composition containing the scrubbing agent.

According to the present invention, it is possible to provide a scrubbing agent having sufficient biodegradability and excellent detergency and usability.

Hereinafter, an example of a preferred embodiment will be specifically described.

[Scrub agent]
The scrubbing agent of the present disclosure comprises porous cellulose particles. Here, the scrubbing agent is a makeup for removing pores such as keratin, sebum, dust, and waste products and dirt on the skin surface (skin) to beautify the skin and nails of the body, face, scalp, etc. The fee.

[Porous Cellulose Particles]
The porous cellulose particles of the present disclosure have a cellulose type II crystal structure, the particle diameter is 100 μm or more and 1,000 μm or less in the median diameter, and the specific surface area obtained by the nitrogen method BET specific surface area measurement method is 10 m ² / g or more and 100 m. ^{It is 2} / g or less, the bulk specific surface area is 0.38 g / ml or more and 0.55 g / ml or less, and the biodegradability rate is 50% by weight or more within 10 days.

[Cellulose type II crystal structure]
The porous cellulose particles of the present disclosure have a cellulose type II crystal structure. The fact that it has a cellulose type II crystal structure means that in the diffraction profile obtained from the X-ray diffraction photograph using CuKα (λ = 1.542184 Å), 2θ = 11 to 13 ° and 2θ = 19 to 21 It can be identified by having typical peaks at three positions near ° and around 2θ = 21-23 °.

Further, having a cellulose I-type crystal structure means that in the diffraction profile obtained from the X-ray diffraction photograph using CuKα (λ = 1.542184 Å), 2θ = 15 to 17 ° and 2θ = 22 to 23. It can be identified by having typical peaks at two locations near °.

[Particle size]
The porous cellulose particles of the present disclosure have a median diameter of 100 μm or more and 1,000 μm or less. The median diameter is preferably 100 μm or more and 900 μm or less, more preferably 100 μm or more and 800 μm or less, further preferably 100 μm or more and 700 μm or less, and most preferably 100 μm or more and 600 μm or less.

When the median diameter is 100 μm or more and 1,000 μm or less, the scrubbing agent composed of the porous cellulose particles has the ability to scrape or scrape off waste products and dirt on the pores and the skin surface (skin). Since it is high, it has excellent detergency, and because it feels good, it has an excellent usability. When the median diameter is less than 100 μm, the ability to remove waste products and dirt on the pores and the skin surface (skin) is low, so that the detergency is inferior and the usability is also inferior. When the median diameter exceeds 1,000 μm, the particles are too large, so that the feel is poor during cleaning and the usability is poor. The detergency refers to the ability to remove pores such as keratin, sebum, and dust, and waste products and dirt on the skin surface (skin).

The median diameter can be measured using dynamic light scattering. Specifically, it is as follows. First, a sample is prepared by preparing a pure water suspension of 100 ppm-concentrated porous cellulose particles using an ultrasonic vibration device. After that, the median diameter is measured by measuring the volume frequency particle size distribution by a laser diffraction method (“SK Laser Micronsizer LMS-2000e” manufactured by Seishin Enterprise Co., Ltd., sonication for 1 minute, refractive index 1.52). Can be done. The median diameter referred to here means a value (μm) of the particle diameter corresponding to an integrated 50% of the scattering intensity in this particle size distribution.

[Specific surface area]
The porous cellulose particles of the present disclosure have a specific surface area of 10 m ² / g or more and 100 m ² / g or less obtained by the nitrogen method BET specific surface area measurement method. The upper limit of the specific surface area ^{is preferably 50 m 2} / g or less, and ^{more preferably 40 m 2} / g or less. The lower limit ^{is preferably 10.6 m 2} / g or more, and more preferably 11 m ² / g or more. When the specific surface area is 10 m ² / g or more and 100 m ² / g or less, the ability to scrape or scrape off waste products and dirt on the pores and skin surface (skin) and oil retention are high and excellent. It has detergency and a sufficient usability. If the specific surface area is ^{less than 10 m 2} / g, the detergency is inferior because the ability to remove waste products and dirt on the pores and the skin surface (skin) and the oil retention property are low. The specific surface area is preferably larger because it improves the detergency, but if it is too large, the oil absorption property is too high, so that the oil content of the skin is absorbed more than necessary and the skin becomes dry. In addition, since the space volume is too large and the shape cannot be maintained, the space becomes brittle, and a sufficient usability required as a scrubbing agent cannot be obtained.

The specific surface area using the nitrogen method BET specific surface area measurement method is determined after the sample is heated and vacuum exhausted in advance at a temperature of 100 ° C. for about 1 hour using a MasterPrep degassing device manufactured by Cantachrome Instruments. Using a surface area measuring device (“Autosorb iQ Station 2” manufactured by Cantachrome Instruments), nitrogen adsorption is measured at about 7 points in the range of relative pressure of 0.05 to 0.28 by the nitrogen gas adsorption method, and the BET method is used. Can be obtained by calculating the specific surface area by applying.

[Bulk specific gravity]
The porous cellulose particles of the present disclosure have a bulk specific gravity of 0.38 g / ml or more and 0.55 g / ml or less. The bulk specific gravity is preferably 0.38 g / ml or more and 0.54 g / ml or less, and more preferably 0.38 g / ml or more and 0.53 g / ml or less. When the bulk specific gravity is 0.38 g / ml or more and 0.55 g / ml or less, deeper pores are formed from the surface of the particles toward the inside, so that waste products and dirt on the pores and the skin surface (skin) are formed. It has a high ability to scrape or scrape off and has excellent detergency. If the bulk specific gravity is too small (particularly, when it is about 0.1 g / ml), the particles tend to fly in the air and are inferior in handleability. If the bulk specific gravity is too large, it will be too hard and the usability will be poor.

The bulk specific gravity can be calculated as the average apparent specific gravity as follows. Using a powder tester (TYPE PT-E, manufactured by Hosokawa Micron Co., Ltd.), the loose apparent specific gravity and the hardened apparent specific gravity can be measured, and the average apparent specific gravity can be calculated by the following formula. Loose apparent specific gravity is obtained by vibrating the sieve, dropping the sample through a chute, receiving it in a specified container and measuring it. The apparent specific gravity of compaction is obtained by placing a sample in a specified container, dropping it from a certain height a specified number of times, solidifying it by the impact of the drop, and then measuring it.
Average apparent specific gravity = (loose apparent specific gravity + firm apparent specific gravity) / 2

[Biodegradability]
The porous cellulose particles of the present disclosure have a biodegradability rate of 50% by weight or more within 10 days. Its biodegradability rate is preferably 55% by weight or more, more preferably 58% by weight or more within 10 days. When the porous cellulose particles of the present disclosure are used as a scrubbing agent and then flow into a river or the sea as wastewater, the scrubbing agent is prevented from adsorbing a trace amount of pollutants such as harmful chemical substances, and further in the river or the sea. Higher biodegradability rates are more likely to reduce the likelihood that inhabiting organisms (coral, shellfish, plankton, etc.) will swallow pollutant-adsorbed scrubbing agents, resulting in less impact of pollutants on the ecosystem. preferable. Therefore, the upper limit value is not particularly limited, but since the impact on the ecosystem can be sufficiently reduced, the upper limit value may be, for example, 90% by weight or less, or 85% by weight or less within 10 days. When the biodegradability rate is 50% by weight or more within 10 days, it has the same biodegradability as natural fruit seeds and coconut shells, and is naturally decomposed by microorganisms and light. If the biodegradability rate is less than 50% by weight, it will stay in rivers and oceans for a long period of time, and as a result of the scrubbing agent adsorbing pollutants such as harmful chemical substances in the environment, the impact of the pollutants on the ecosystem. Becomes larger.

The biodegradability rate can be measured by a method using activated sludge according to JIS K6950.

[Manufacturing of porous cellulose particles]
The porous cellulose particles of the present disclosure can be obtained by the following production method.
Step (I), in which cellulose acetate flakes having a particle size of 120 μm or more and 1,000 μm or less and an acetyl substitution degree of 2.0 or more are immersed in an organic solvent / water mixed solution to swell and are saponified with an excessive amount of strong base. A step of neutralizing the saponified cellulose acetate flakes with a neutralizing agent (II), a step of solid-liquid separation of the obtained slurry containing the cellulose particles after the neutralization, and a step of obtaining solid-phase cellulose particles (III). It includes a step (IV) of washing the cellulose particles with water and then washing with an organic solvent, and a step (V) of drying the washed cellulose particles.

(Saponification step (I))
Details of step (I) of swelling cellulose acetate flakes with a particle size of 120 μm or more and 1,000 μm or less and an acetyl substitution degree of 2.0 or more in an organic solvent / water mixed solution and saponifying with an excess amount of strong base. Describe. In addition, saponification can be paraphrased as deacetylation.

The particle size of the cellulose acetate flakes is preferably 120 μm or more and 1,000 μm or less, and more preferably 120 μm or more and 900 μm or less, 120 μm or more and 800 μm or less, 120 μm or more and 700 μm or less, and 120 μm or more and 650 μm or less.

The particle size of the cellulose acetate flakes may be adjusted to 120 μm or more and 1,000 μm or less by mechanically pulverizing. Mechanical crushing can be done by a conventional crusher. As the crusher, for example, a sample mill, a hammer mill, a turbo mill, an atomizer, a cutter mill, a bead mill, a ball mill, a roll mill, a jet mill, a pin mill and the like can be used. Among these, it is preferable to use a pin mill. Further, freeze pulverization, dry pulverization at room temperature, or wet pulverization may be performed.

When the cellulose acetate flakes used for producing the porous cellulose particles of the present disclosure are classified by the degree of acetyl substitution, cellulose triacetate (degree of acetyl substitution (DS): 2.6 or more and 3 or less) and cellulose diacetate (degree of acetyl substitution (DS)) are classified. ): 2.0 or more and less than 2.6). Specifically, for example, the cellulose triacetate is LT-55 (manufactured by Daicel Corporation), and the cellulose diacetate is L-50. (Manufactured by Daicel Co., Ltd.) and the like.

As the cellulose acetate flakes, it is preferable to use cellulose triacetate having a higher degree of acetyl substitution from the viewpoint that the specific surface area of the obtained porous cellulose particles can be further increased. On the other hand, from the viewpoint that the time required for saponification can be shortened and the productivity can be increased, it is preferable to use cellulose diacetate having a relatively low degree of acetyl substitution.

The organic solvent / water mixed solution used in the saponification step (I) is not particularly limited as long as the cellulose acetate flakes can be swollen, but since it is economically inexpensive, an isopropyl alcohol / water mixed solution and an acetone / water mixed solution are used. , Ethanol / water mixed solution, methanol / water mixed solution and the like. Among these, it is particularly preferable to use an isopropyl alcohol / water mixed solution because the cellulose acetate flakes are excellent in swelling property.

The composition of these organic solvent / water mixed solutions can be any ratio as long as the organic solvent and water are not separated from each other and are mixed, and the composition is not limited, but is excellent in swelling property. Therefore, the organic solvent is an organic solvent. It is preferably 40% by weight or more and 80% by weight or less, more preferably 40% by weight or more and 70% by weight or less, and further preferably 40% by weight or more and 60% by weight or less with respect to the total weight of water. ..

Further, since the swelling property of the organic solvent / water mixed solution changes depending on the degree of acetyl substitution of the cellulose acetate flakes, it is preferable to appropriately adjust the composition according to the degree of substitution. For example, in the case of cellulose diacetate having a degree of acetyl substitution of cellulose acetate flakes of 2.0 or more and less than 2.6, the composition of the organic solvent / water mixed solution is such that the organic solvent is 20% by weight based on the total weight of the organic solvent and water. 80% by weight or more is preferable, 35% by weight or more and 70% by weight or less is more preferable, 35% by weight or more and 60% by weight or less is further preferable, and 37% by weight or more and 52% by weight or less is most preferable. In the case of cellulose triacetate having an acetyl substitution degree of 2.6 or more and 3 or less of cellulose acetate flakes, it is preferably 50% by weight or more and 80% by weight or less, and more preferably 55% by weight or more and 75% by weight or less. ..

In the saponification step (I), the amount of water in the organic solvent / water mixed solution is not particularly limited, but is preferably 800 parts by weight or more and 1,000 parts by weight or less with respect to 100 parts by weight of the cellulose acetate flakes.

It can be visually determined that the cellulose acetate flakes have swollen by immersing the cellulose acetate flakes in an organic solvent / water mixed solution. Swelling is a state in which cellulose acetate flakes become an opaque suspension that has absorbed an organic solvent. As proposed by Flory et al., The dissolution of a polymer compound is a state in which a transparent solution in which the polymer chain can be freely extended is dissolved. Here, in order to swell the cellulose acetate flakes, it is preferable to immerse the cellulose acetate flakes in an organic solvent / water mixed solution at room temperature (23 ° C.) for 60 minutes or more. The upper limit of the time is not particularly limited, but if it is too long, cellulose acetate may dissolve. Therefore, for example, it is 3 hours or less at room temperature.

By sufficiently swelling the cellulose acetate flakes in this way, the strong base described below rapidly and uniformly permeates deep inside the cellulose acetate, and saponification easily proceeds deep inside the cellulose acetate. As a result, as will be described in the subsequent drying step (V), the organic solvent and water contained deep inside the cellulose particles escape from the inside of the cellulose particles to form a porous portion of the porous cellulose particles, and the specific surface area is formed. Can obtain large porous cellulose particles.

An excess amount of strong base used in the saponification step (I) will be described. Examples of the strong base include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, barium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide or a mixture thereof. These strong bases can be used as an aqueous solution. As the strong base, it is preferable to use an aqueous sodium hydroxide solution from the viewpoint of economy. As the sodium hydroxide aqueous solution, for example, 2% by weight or more and 6% by weight or less can be used.

Here, the excess amount means an equivalent amount exceeding twice the equivalent amount with respect to the number of moles of acetyl groups present in the cellulose acetate flakes. The excess amount of sodium hydroxide means an amount containing sodium ions in excess of twice the equivalent amount with respect to the number of moles of acetyl groups present in the cellulose acetate flakes. Preferably, it is 5 times equivalent or more.

When cellulose diacetate is used as the cellulose acetate flakes, about 150 parts by weight can be used with respect to 100 parts by weight of the cellulose acetate flakes as long as it is an aqueous solution of 4% by weight of sodium hydroxide.

In the saponification step (I), once the swelling and saponification of the cellulose acetate flakes are completed, the order in which the organic solvent / water mixed solution, the excess amount of the strong base and the cellulose acetate flakes are put into the reactor is not limited. Cellulose acetate flakes may be saponified by immersing them in an organic solvent / water mixed solution to sufficiently swell them, and then adding an excess amount of strong bases, or in advance, an organic solvent / water mixed solution and an excess amount of strong bases may be added. May be added to the mixture of cellulose acetate flakes. Further, when the cellulose acetate flakes are immersed in the organic solvent / water mixed solution, an excessive amount of strong base may be added at the same time or without a gap. Among these, it is preferable to add cellulose acetate flakes in a mixture of an organic solvent / water mixed solution and an excessive amount of strong bases in advance. In any case, it is preferable to stir and mix in the reactor.

Here, saponification means that the degree of acetyl substitution of the cellulose acetate flakes becomes substantially zero. The degree of acetyl substitution of the cellulose acetate flakes is determined by measuring the absorption intensity due to the carboxyl group of the infrared (IR) absorption spectrum 1740 to 1750 cm ^{-1 and quantitatively evaluating it.} At this time, among the methods for measuring the infrared (IR) absorption spectrum, it is particularly preferable to use the ATR method or the like for solid cellulose acetate.

In the saponification step (I), the temperature in the reaction system when the cellulose acetate flakes are saponified with an excessive amount of strong base can be set to room temperature. Here, the normal temperature means about 30 ° C. That is, in the present disclosure, since the heat generated by the reaction in the saponification step (I) is not small, the temperature rise of the reaction system in the saponification step (I) is slight.

Further, when the cellulose acetate flakes are dipped in an organic solvent / water mixed solution to sufficiently swell, and then saponified by adding an excessive amount of a strong base, they are dipped in an organic solvent / water mixed solution to sufficiently swell. The temperature in the system may be 20 ° C. or higher and 40 ° C. or lower, and may be room temperature (23 ° C.).

The time for saponifying the cellulose acetate flakes with an excessive amount of strong base is not particularly limited as long as the saponification is completed. In the case of cellulose triacetate (acetyl substitution degree (DS): 2.6 or more and 3 or less), saponification is completed in about 2 hours or more and 24 hours after adding an excessive amount of sodium hydroxide aqueous solution at room temperature. be able to. In the case of cellulose diacetate (acetyl substitution degree (DS): 2.0 or more and less than 2.6), at room temperature, for example, after adding an excessive amount of sodium hydroxide aqueous solution, saponification takes about 6 hours or more and 12 hours. Can be completed. The higher the degree of substitution of cellulose acetate flakes, the longer it takes to complete saponification.

(Neutralization step (II))
The step (II) of neutralizing the saponified cellulose acetate flakes with a neutralizing agent will be described in detail.

In the neutralization step (II), after the saponification of the cellulose acetate flakes is completed in the saponification step (I), the neutralizing agent is added to the reaction solution obtained by adding an organic solvent / water mixed solution and a strong base to cellulose acetate. By adding, the neutralization reaction is started and the reaction solution is neutralized. Neutralization brings the pH of the reaction solution as close to pH 7 as possible.

Examples of the neutralizing agent include acids such as acetic acid, propionic acid and hydrochloric acid. Further, it is preferable to use acetic acid of about 2.9% by weight to 3.5% by weight.

The amount of the neutralizing agent may be an amount capable of neutralizing the reaction solution, and is added so that the pH becomes 7.

In the neutralization step (II), the temperature in the reaction system is preferably adjusted to 10 ° C. or higher and 40 ° C. or lower, and preferably 20 ° C. or higher and 30 ° C. or lower. Since heat is generated by the heat of neutralization, it is preferable to control the temperature to 40 ° C. or lower.

The time of the neutralization reaction in the neutralization step (II) is not particularly limited as long as the neutralization reaction proceeds sufficiently, but is preferably 10 minutes or more and 30 minutes or less, for example.

(Solid-liquid separation step (III))
After the neutralization, the step (III) of solid-liquid separating the obtained slurry containing the cellulose particles to obtain solid-phase cellulose particles will be described in detail.

After the neutralization, the cellulose acetate flakes become cellulose by saponification, and the reaction solution subjected to the neutralization reaction becomes a slurry containing cellulose particles. Cellulose particles forming a solid phase can be obtained by solid-liquid separation of the slurry containing the cellulose particles. Here, the solid-liquid separation can also be performed by using a centrifugal deflated machine. For example, a solid-liquid separator of GEA Westfalia Separator Japan Co., Ltd. can be used. As the conditions of the centrifugal desorber, the rotation speed and the separation time may be adjusted according to the normal operation conditions for centrifuging particles.

(Washing step (IV))
The step (IV) of washing the cellulose particles with water and then washing with an organic solvent will be described in detail.

By washing the cellulose particles obtained in the solid-liquid separation step (III) with water, the strong base required for saponification, the neutralizing agent required for neutralization, and the salt with which they have reacted can be washed away. Specifically, the washing with water is performed by mixing 100 parts by weight of cellulose particles with 4,000 parts by weight or more and 5,000 parts by weight or less of water and separating them into solid and liquid by a centrifugal deflated machine. be able to. When the process from mixing cellulose particles and water to solid-liquid separation by a centrifugal deflated machine is performed once, the number of times is not particularly limited as long as neutralizing salts and the like can be prevented from remaining, but the result of neutralization In order to thoroughly wash away the produced salt, for example, sodium acetate, it is preferable to carry out the procedure three times or more in total.

The organic solvent used for washing the cellulose particles may be an organic solvent alone or a mixed organic solvent / water solution as long as the organic solvent is contained. Further, the organic solvent / water mixed solution may be the same as or different from the organic solvent / water mixed solution used in the saponification step (I). Examples of this organic solvent include isopropyl alcohol and acetone, but a lipophilic solvent is preferable and isopropyl alcohol is preferably used in the sense that the particles prevent secondary aggregation.

As described above, by washing the cellulose particles with water and then with an organic solvent, the formation of hydrogen bonds in the cellulose particles can be prevented and the particles can be easily dried. Aggregation can be prevented.

When an organic solvent / water mixed solution is used, the composition may be any ratio as long as the organic solvent and water are not separated from each other and are mixed, and the composition is not particularly limited, but in consideration of solubility and the like. The organic solvent is preferably 5% by weight or more and 20% by weight or less, and more preferably 7% by weight or more and 15% by weight or less with respect to the total weight of the organic solvent and water.

Specifically, the washing with the organic solvent is the same as the washing with water. For example, 300 parts by weight or more and 600 parts by weight or less of the organic solvent are mixed with 100 parts by weight of the cellulose particles, and the solid liquid is solidified by a centrifugal deflated machine. It can be done by separating. When the process from mixing the cellulose particles and the organic solvent to the solid-liquid separation by the centrifugal liquidator is performed once, the number of times is not particularly limited as long as the cellulose particles can be prevented from aggregating, but the substitution with the organic solvent is performed. In order to ensure it, it is preferable to perform it once or more and three times or less in total.

(Drying step (V))
The step (V) of drying the washed cellulose particles will be described in detail.

By drying the washed cellulose particles, the organic solvent and water contained deep inside the cellulose particles escape from the inside of the cellulose particles, a porous portion of the porous cellulose particles is formed, and the porous cellulose particles have a large specific surface area. It becomes.

The method for drying the washed cellulose particles is not particularly limited as long as the porous cellulose particles can be formed, but it is preferable to use a vacuum drying method. The drying pressure in the vacuum drying method may be, for example, about 10 kPa · A. Examples of the dryer used in the vacuum drying method include a Nauter type dryer, a conical dryer, a paddle dryer, a shelf type dryer, a vibration flow dryer and a band ventilation dryer.

The finally obtained porous cellulose particles are somewhat smaller than the median diameter of the cellulose acetate flakes used as the raw material. This is associated with shear collision due to stirring or the like in each step such as the saponification step (I) or the neutralization step (II), dissolution, or a chemical reaction due to saponification in the saponification step (I).

A certain amount of acetyl groups based on cellulose acetate flakes remain inside the obtained porous cellulose particles. This is because the production of the porous cellulose particles of the present disclosure uses a heterogeneous reaction in which the cellulose acetate flake raw material is swelled with a solvent and then saponified with a strong base, as described above. This is because saponification does not easily proceed and acetyl groups tend to remain.

Further, the obtained porous cellulose particles have an indefinite shape. Since the obtained porous cellulose particles have an indefinite shape, they are excellent in detergency. In order to obtain an indefinite shape, it is preferable to mechanically pulverize the cellulose acetate flake raw material as described above. The indefinite shape refers to the shape of the surface of the porous cellulose particles, and refers to a shape having irregularities rather than a spherical shape having no irregularities on the particle surface.

[Skin cleansing composition]
The skin cleansing composition of the present disclosure contains the scrubbing agent. The skin cleansing composition refers to a composition for washing the skin such as the body, face, and scalp. Examples of the skin cleansing composition include a facial cleansing composition, a scalp cleansing composition (shampoo), and a body cleansing composition (body shampoo).

The content of the scrubbing agent in the skin cleansing composition is preferably 2% by weight or more and 20% by weight or less, more preferably 3% by weight or more and 15% by weight or less, and 5% by weight or more and 10% by weight or less. Is even more preferable. Within this range, the scrubbing agent exhibits good dispersibility in the skin cleansing composition, and it is possible to achieve both sufficient cleansing power and a feeling of use when using the scrubbing agent.

The skin cleansing composition of the present disclosure may take any form of liquid preparations such as aqueous solutions, emulsions and suspensions; semi-solid preparations such as gels and creams; solid preparations such as powders, granules and solids.

As the components other than the scrubbing agent of the skin cleaning composition of the present disclosure, those contained in the conventional skin cleaning composition can be adopted, and for example, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can be adopted. Surfactants such as activators and nonionic surfactants; polyhydric alcohols such as glycerin; fats and oils such as vegetable oils; hydrocarbons such as squalane; higher fatty acids such as lauric acid and myristic acid; higher alcohols such as lauryl alcohol Silicone such as dimethylpolysiloxane of chain polysiloxane; Preservative; Thickener; Metal ion blocking agent; Polymer such as water-soluble polymer; UV absorber; UV blocker; Moisturizer such as hyaluronic acid and amino acid Perfume; pH adjuster; pearlizing agent; desiccant; vitamins; skin activator; blood circulation promoter; indigenous bacteria control agent; active oxygen scavenger; anti-inflammatory agent; whitening agent; bactericidal agent; and physiologically active ingredient Etc. can also be contained.

Hereinafter, the present invention will be specifically described with reference to Examples, but the technical scope of the present invention is not limited by these Examples.

Each of the physical properties described in Examples and Comparative Examples described later was evaluated by the following method.

<Median diameter>
The median diameter was measured using dynamic light scattering. First, pure water was used to make the sample 100 ppm concentration, and an ultrasonic vibration device was used to prepare a pure water suspension. Then, the median diameter was measured by measuring the volume frequency particle size distribution by a laser diffraction method (“SK Laser Micronsizer LMS-2000e” manufactured by Seishin Enterprise Co., Ltd., sonication for 1 minute, refractive index 1.52). The median diameter referred to here is a value (μm) of the particle diameter corresponding to the cumulative 50% of the scattering intensity in the particle size distribution.

<Specific surface area>
A sample is heated and evacuated in advance at a temperature of 100 ° C. for about 1 hour using a MasterPrep degassing device (Cantachrome Instruments Japan GK), and then a specific surface area measuring device (manufactured by Cantachrome Instruments). Using "Autosorb iQ Station 2"), the BET equation (1) was determined in the range of relative pressure of 0.05 to 0.28 by the nitrogen gas adsorption method.

ここで、Ｐは吸着平衡における吸着質の気体の圧力、Ｐ_０は吸着平衡における吸着質の飽和蒸気圧、Ｗは吸着平衡圧Ｐにおける吸着量、Ｗｍは単分子吸着量、ＣはＢＥＴ定数である。ｘ軸を相対圧力Ｐ_０／Ｐ、ｙ軸を１／［Ｗ・｛（Ｐ_０／Ｐ）−１｝］としてプロット（ＢＥＴプロット）すると線形となる。このプロットは７点行ったものであり、その直線の勾配と切片の和の逆数から単分子吸着量Ｗｍを得た。

Here, P is the pressure of the adsorbent gas in the _{adsorption equilibrium, P 0} is the saturated vapor pressure of the adsorbate in the adsorption equilibrium, W is the adsorption amount in the adsorption equilibrium pressure P, Wm is the single molecule adsorption amount, and C is the BET constant. is there. When the x-axis is the relative pressure P ₀ / P and the y-axis is 1 / [W · {(P ₀ / P) -1}], the plot (BET plot) is linear. This plot was performed at 7 points, and the single molecule adsorption amount Wm was obtained from the reciprocal of the sum of the gradient of the straight line and the intercept.

Next, the specific surface area Ss is calculated by the following formula.
Ss = (Wm ・ N ・ Acs ・ M) / w
Here, N is the Avogadro's number, M is the molecular weight, Acs is the adsorption cross-sectional area, and w is the sample weight. The specific surface area, which is the surface area per 1 g of the solid sample, was determined by setting the adsorption cross-sectional area Acs of the nitrogen gas molecule to 0.162 nm ² (16.2 Å ^2).

<Bulk specific gravity (average apparent specific gravity)>
The bulk specific gravity was calculated as the average apparent specific gravity as follows. Using a powder tester (TYPE PT-E, manufactured by Hosokawa Micron Co., Ltd.), the loose apparent specific gravity and the hardened apparent specific gravity were measured, and the average apparent specific gravity was calculated. The apparent specific gravity of looseness was measured by vibrating the sieve, dropping the sample through a chute, receiving it in a specified container, and measuring it. The apparent specific gravity of compaction was measured after placing the sample in a specified container, dropping it from a certain height a specified number of times, and then solidifying it with the impact of the drop. Then, the average apparent specific gravity was calculated by the following formula.
Average apparent specific gravity = (loose apparent specific gravity + firm apparent specific gravity) / 2

<Biodegradable rate>
The biodegradability rate was measured by a method using activated sludge according to JIS K6950.
Activated sludge was obtained from a sewage treatment plant. About 300 mL of the supernatant (activated sludge concentration: about 360 ppm) obtained by leaving the activated sludge for about 1 hour was used per culture bottle. The measurement was started at the time when 0.03 g of the sample was stirred in the supernatant, the first measurement was performed 24 hours later, and the measurement was performed 21 times every 24 hours thereafter. Within 10 days from the start of measurement to 240 hours later. The details of the measurement are as follows. The biochemical oxygen demand (BOD) in each culture bottle was measured using a coolometer OM3001 manufactured by Okura Electric Co., Ltd., and the biodegradability (%) was calculated based on the chemical composition of each sample.

<Solid content concentration>
The solid content concentration was determined by the heating weight subtraction method. That is, it was measured as follows. Approximately 10 g of the sample is weighed on an aluminum dish (W2), dried in a vacuum dryer at 60 ° C. for 3 hours, cooled to room temperature in a desiccator, and then weighed (W3), and the solid content concentration can be determined according to the following formula. ..
Solid content concentration (%) = (W3-W1) / (W2-W1) × 100
W1 is the weight of the aluminum plate (g), W2 is the weight of the aluminum plate containing the sample before drying (g), and W3 is the weight of the aluminum plate containing the sample after drying (g).

(Example 1)
The reactor was charged with 351.4 parts by weight of isopropyl alcohol (IPA), 411.1 parts by weight of pure water (IPA concentration 46.08% by weight), and 74.7 parts by weight of a 48% by weight aqueous sodium hydroxide solution. Further, 50 parts by weight of (cellulose acetate flakes having a median diameter of 130 μm and an acetyl substitution degree (DS): 2.45) were added as cellulose acetate flakes, and the reactor was set to a set temperature of 30 ° C. for 6 hours with stirring and mixing. It was.

Next, 26.9 parts by weight of acetic acid was added to the reactor, the temperature of the reactor was controlled to 40 ° C. or lower, and stirring and mixing was carried out for 30 minutes. The obtained reaction solution was in the form of a slurry. Cellulose particles on a solid phase were separated from this slurry-like reaction solution using a centrifugal deflated machine. The separated cellulose particles were 516 parts by weight, and the solid content concentration was about 12% by weight. Subsequently, 258 parts by weight of the obtained cellulose particles (wet powder; cake after deliquescent) and 500 parts by weight of water were mixed, and the cellulose particles of the solid phase were separated by using a centrifugal desorption machine. Cellulose particles were washed with water. Similarly, the cellulose particles were washed with water three more times.

Then, 285 parts by weight of cellulose particles (wet powder; cake after deliquescent) and 500 parts by weight of isopropyl alcohol (IPA) are mixed, and the cellulose particles of the solid phase are separated by using a centrifugal desorption machine. Cellulose particles were washed with isopropyl alcohol (IPA). Similarly, the cellulose particles were washed once more with isopropyl alcohol (IPA). Finally, the cellulose particles were dried by a conical dryer under the condition of full vacuum at 80 ° C. for 48 hours to obtain porous cellulose particles. The median diameter, specific surface area, bulk specific gravity and biodegradability rate of the obtained porous cellulose particles were determined. The results are shown in Table 1. The crystal structure of cellulose measured by X-ray diffraction of the porous cellulose particles obtained in Example 1 was a cellulose type II crystal structure.

(Example 2)
As the cellulose acetate flakes, except that cellulose acetate flakes having a median diameter of 277 μm and an acetyl substitution degree (DS) of 2.45 were used instead of the cellulose acetate flakes having a median diameter of 130 μm and an acetyl substitution degree (DS) of 2.45. Porous cellulose particles were obtained in the same manner as in Example 1. The median diameter, specific surface area, and bulk specific gravity of the obtained porous cellulose particles were determined. The results are shown in Table 1. The crystal structure of cellulose measured by X-ray diffraction of the obtained porous cellulose particles was a cellulose type II crystal structure.

(Example 3)
As the cellulose acetate flakes, except that cellulose acetate flakes having a median diameter of 400 μm and an acetyl substitution degree (DS) of 2.45 were used instead of the cellulose acetate flakes having a median diameter of 130 μm and an acetyl substitution degree (DS) of 2.45. Porous cellulose particles were obtained in the same manner as in Example 1. The median diameter, specific surface area, and bulk specific gravity of the obtained porous cellulose particles were determined. The results are shown in Table 1. The crystal structure of cellulose measured by X-ray diffraction of the obtained porous cellulose particles was a cellulose type II crystal structure.

(Example 4)
As the cellulose acetate flakes, except that cellulose acetate flakes having a median diameter of 700 μm and an acetyl substitution degree (DS) of 2.45 were used instead of the cellulose acetate flakes having a median diameter of 130 μm and an acetyl substitution degree (DS) of 2.45. Porous cellulose particles were obtained in the same manner as in Example 1. The median diameter, specific surface area, and bulk specific gravity of the obtained porous cellulose particles were determined. The results are shown in Table 1. The crystal structure of cellulose measured by X-ray diffraction of the obtained porous cellulose particles was a cellulose type II crystal structure.

(Comparative Example 1)
The median diameter, specific surface area, and bulk specific gravity of the cellulose particles and Asahi Kasei Corporation Theoras (registered trademark) FD101 were determined in the same manner as in Example 1. The results are shown in Table 1. The particles had a fairly structure I type. The results are shown in Table 1.

(Comparative Example 2)
For polyethylene particles and MSC50PC of DSP Gokyo Food & Chemical Co., Ltd., the median diameter was determined in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
The median diameter, specific surface area, and bulk specific gravity of the cellulose particles and Bisco Pearl Mini (registered trademark) of Rengo Co., Ltd. were determined in the same manner as in Example 1. The results are shown in Table 1. The particles were fairly structural type II. The results are shown in Table 1.

(Example 5)
(1) Preparation of Cleaning Composition Containing Scrub Agent Potassium laurate, potassium myristate, glycerin, propylene glycol and hydroxypropyl cellulose were mixed with ion-exchanged water and dissolved by heating at 60 ° C. Then, ethylene glycol distearate was added, and the porous cellulose particles produced in Example 2 as a scrubbing agent were added and mixed uniformly. This was cooled to room temperature to obtain a cleaning composition (liquid agent) containing a scrubbing agent. The blending amount of each blending component is as shown in Table 2.

(2) Evaluation of usability The usability of the cleaning composition obtained in (1) was evaluated by the following method.
Each of the five panelists applied a small amount of the cleaning composition obtained in (1) to the back of the hand and performed rubbing cleaning with fingers. The evaluation was evaluated in the following three stages. The evaluation result was the most frequently evaluated among the five. The results are shown in Table 2.
◯: Comfortable with a smooth feel and moderate irritation.
Δ: The stimulus tends to be strong, and there is a slight sense of discomfort.
×: Stimulation is strong and it hurts.

(3) Evaluation of detergency The detergency of the cleaning composition obtained in (1) was evaluated by the following method.
A small amount of model sebum colored with carbon black was applied to the back of the hand and dried, and then the cleaning composition obtained in (1) was applied, and the model was washed by rubbing with fingers and washed with water. Furthermore, after drying, the degree of model sebum remaining on the back of the hand was observed with an optical microscope and evaluated in the following three stages. The results are shown in Table 2.
◯: Almost all the dirt is removed, and the cleaning power is high.
Δ: About 70% of the dirt has been removed, and the cleaning power is medium.
X: Dirt removal is insufficient and detergency is low.

(Example 6)
For cleaning containing a scrubbing agent in the same manner as in Example 5, except that the porous cellulose particles produced in Example 3 were used instead of the porous cellulose particles produced in Example 2 as the scrubbing agent. A composition (liquid agent) was obtained, and the feeling of use and the detergency were evaluated. The results are shown in Table 2.

(Comparative Example 4)
Cleaning containing a scrubbing agent in the same manner as in Example 5 except that cellulose particles and Asahi Kasei Co., Ltd. Theoras (registered trademark) FD101 were used instead of the porous cellulose particles produced in Example 2 as the scrubbing agent. A composition (liquid agent) for use was obtained, and the feeling of use and the detergency were evaluated. The results are shown in Table 2.

(Comparative Example 5)
Cleaning containing a scrubbing agent in the same manner as in Example 5 except that polyethylene particles and DSP Gokyo Food & Chemical Co., Ltd. MSP50PC were used instead of the porous cellulose particles produced in Example 2 as the scrubbing agent. A composition (liquid agent) for use was obtained, and the feeling of use and the detergency were evaluated. The results are shown in Table 2.

(Comparative Example 6)
As the scrubbing agent, the scrubbing agent is contained in the same manner as in Example 5 except that cellulose particles and Viscopearl Mini (registered trademark) of Rengo Co., Ltd. are used instead of the porous cellulose particles produced in Example 2. A cleaning composition (liquid agent) was obtained, and the feeling of use and the detergency were evaluated. The results are shown in Table 2.

As shown in Table 1, the porous cellulose particles of the present disclosure are made of cellulose and therefore have excellent biodegradability. Then, as shown in Table 2, the cleaning compositions (Examples 5 and 6) containing the porous cellulose particles of Examples 2 and 3 having a predetermined particle size, specific surface area, and bulk specific gravity as a scrubbing agent It was confirmed that all of them have a smooth feel and moderate irritation, are excellent in usability, and have high detergency. On the other hand, the cleaning composition (Comparative Example 4) containing the porous cellulose particles of Comparative Example 1 having insufficient particle diameter, specific surface area, and bulk specific gravity as a scrubbing agent has a feeling of strangeness in use. It was confirmed that the cleaning power was low. It was confirmed that the cleaning composition (Comparative Example 5) containing the polyethylene particles of Comparative Example 2 as a scrubbing agent was moderately irritating and comfortable, but the detergency was moderate and inferior. It was confirmed that the cleaning composition (Comparative Example 6) containing the porous cellulose particles of Comparative Example 3 having a low bulk specific gravity as a scrubbing agent was also comfortable with moderate irritation, but the detergency was moderate and inferior. ..

Claims (5)

A scrubbing agent composed of porous cellulose particles
The porous cellulose particles are
Has a cellulose type II crystal structure
Particle diameter is 100 μm or more and 1,000 μm or less in median diameter,
The specific surface area obtained by the nitrogen method BET specific surface area measurement method is 10 m ² / g or more and 100 m ² / g or less.
The bulk specific gravity is 0.38 g / ml or more and 0.55 g / ml or less.
And a scrubbing agent having a biodegradable rate of 50% by weight or more within 10 days. The scrubbing agent according to claim 1, wherein the porous cellulose particles have a median diameter of 100 μm or more and 900 μm or less. The scrubbing agent according to claim 1, wherein the specific surface area of the porous cellulose particles obtained by the nitrogen method BET specific surface area measurement method is 10 m ² / g or more and 50 m ^{2 / g or less.} A skin cleansing composition containing the scrubbing agent according to any one of claims 1 to 3. A facial cleansing composition containing the scrubbing agent according to any one of claims 1 to 3.