JP5154037B2 - Hydrogel particles - Google Patents

Description

  The present invention relates to a hydrogel particle having excellent cleaning power and massage effect on an object to be cleaned, and having extremely good washability with rinse water or tears.

  In recent years, various washing-type skin cleansing agents (whole body cleansing agents, facial cleansers, massage creams, etc.) containing particles (scrub agents) have been sold and used. The reason for this is that, in addition to the new feeling of use, there is an advantage that it is possible to remove things that are difficult to remove with ordinary skin cleansing agents such as extra keratin (stain) and dirt that has entered pores due to physical effects.

  In addition, it is known that a scrub agent with high detergency and low irritation can be obtained by controlling the size and hardness of the particle in consideration of problems such as irritation to the skin and rough skin (Patent Literature). 1, Patent Document 2).

  However, detergents that contain a scrub agent with controlled particle size and hardness have problems in use such as feeling foreign matter during massage, difficult to wash off after washing, and difficult to remove when in contact with eyes. There is a growing need for particles with these improvements. Patent Document 3 discloses a detergent composition having a specific gravity of 1 or less and containing cross-linked polymer particles of a (meth) acrylic acid ester-based monomer and having good washability of particles after washing. However, the particles disclosed herein are hydrophobic cross-linked polymer particles, and are likely to cause adhesion and aggregation between particles in water, and the apparent particle size may be increased.

On the other hand, Patent Document 4 discloses a water-soluble polymer molded article containing bubbles and having a specific gravity of less than 1. Particularly, when used as a bath agent, it does not sink in water and has a unique property as a bath agent. It is described that it has. This polymer molded product is obtained by mixing an aqueous solution containing a water-soluble polymer compound and a cell regulator, containing bubbles, and then molding and drying into a sheet or the like. It itself dissolves in water (about 40 ° C. hot water).
Japanese Patent Laid-Open No. 2-151593 JP-A-9-31492 JP-A-6-57293 JP-A-62-81432

  An object of the present invention is to provide hydrogel particles that have a high detergency and good usability and can be easily removed from eyes and skin after washing.

  The present inventor has high detergency and good usability by including bubbles in the hydrogel, making the specific gravity less than the specific gravity of water or tears, and further making the particles have an average particle size of 50 to 500 μm. Thus, it has been found that hydrogel particles can be obtained that have less adhesion and aggregation between particles in an aqueous system and can be easily removed from eyes and skin after washing.

  That is, the present invention provides hydrogel particles containing bubbles, having a specific gravity of 0.7 to 1.00 and an average particle size of 50 to 500 μm, and a method for producing the same.

  The hydrogel particles of the present invention have an excellent physical cleaning effect, and are extremely low irritation and low damage to the surface of the object to be cleaned, such as the skin and scalp, and have a good feel during cleaning. It is a safer hydrogel particle that can be easily removed from eyes, skin, etc. after washing.

  The hydrogel particles of the present invention are hydrogel particles containing bubbles, having a specific gravity of 0.7 to 1.00 and an average particle size of 50 to 500 μm.

  The “hydrogel” in the present invention is a gel that is gelled by a gel-forming agent using water as a solvent, and gelation does not occur by reaction with ions, such as potassium ions or calcium ions. This is caused by the thermoreversibility of the sol-gel as in the case where the forming agent is agar.

  The shape of the hydrogel particles of the present invention is not particularly limited, but preferred particle shapes include spherical or elliptical shapes. Moreover, the average particle diameter of the hydrogel particle of this invention is 50 micrometers or more from a viewpoint of giving a scrub feeling, and 60 micrometers or more are preferable. In addition, the anxiety of mixing into the eye is reduced, and the discomfort and skin irritation are less likely to occur.

  In the present invention, the average particle size of the hydrogel particles is randomized by observing the particles with a low magnification zoom lens (VH-6300 (main body) manufactured by Keyence Corporation, VH-Z05 (CCD camera lens) manufactured by Keyence Corporation). The particle size of 10 particles selected in the above was compared with the scale and calculated proportionally.

  Further, the specific gravity of the hydrogel particles of the present invention is 1.00 or less, preferably less than 1.00, preferably 0.99 or less, from the viewpoint of being easily removed from the skin, eyes, etc. during washing and less likely to cause a foreign body sensation. Is more preferable, and 0.98 or less is particularly preferable. Moreover, from a viewpoint of giving moderate strength of the hydrogel particles, it is 0.7 or more, preferably 0.8 or more, and more preferably 0.85 or more.

  In the present invention, the specific gravity of the hydrogel particles is determined by arbitrarily preparing an ethanol aqueous solution at 25 ° C. described in Chemical Handbook (Edition 4 edition, page II-12, Maruzen Co., Ltd., Japan Chemical Society). It was measured by floating hydrogel particles.

  The hydrogel particles of the present invention are preferably hydrophilic hydrogel particles containing a gel-forming agent derived from a natural polymer compound. Examples of gel formers derived from natural polymer compounds include agar, gelatin, gum arabic, quince seed mucus, tragacanth gum, guar gum, karaya gum, locust bean gum, glucomannan, pectin, galactan, pullulan, xanthan gum, casein, casein Examples include potassium salt, sodium caseinate, sodium chondroitin sulfate, starch-based semisynthetic polymer compound (for example, carboxymethyl starch, methylhydroxypropyl starch, methylhydroxymethyl starch, etc.), dextrin, and agar and gelatin are preferred. The gel forming agent can be used singly or in combination of two or more of these. From the viewpoint of obtaining the effects of the present invention, agar is particularly preferred, and the hydrogel particles are composed mainly of this. Is more preferable.

In addition, it is preferable that it is 147 kPa (1500 g / cm < ² >) or less from the viewpoint of the feel at the time of use when applying to the cosmetics etc., and 19.6 kPa (200 g / cm < ² >)-127 kPa (1300 g) / Cm ² ) is more preferable. The jelly strength can be determined by the Nissho water method. Specifically, the jelly strength was determined by producing a 1.5% by weight aqueous solution of a gel-forming agent and allowing the aqueous solution to solidify by standing at 20 ° C. for 15 hours. The maximum mass (g) per surface area of 1 cm ² when the gel withstands the load at 20 ° C. for 20 seconds at 20 ° C.

  The gelation temperature of the hydrogel is preferably 30 ° C. or higher, and more preferably 35 ° C. or higher, from the viewpoint of preventing dissolution during washing and blending into cosmetics. Further, from the viewpoint of easy washing away, it is preferably 45 ° C. or lower, more preferably 40 ° C. or lower. For example, in the case of agar, the dissolution temperature in water is generally 75 ° C. or higher, the main one is 75 to 90 ° C., and the gelation temperature when cooled after being dissolved in water is 30 to 45 ° C. .

  The content of the gel-forming agent in the hydrogel particles of the present invention has a good feel when used when applied to cosmetics, etc., and prevents disintegration when the hydrogel particles are washed and blended into cosmetics etc. From this viewpoint, 0.1 to 8.0% by mass is preferable, 0.3 to 7.0% by mass is more preferable, 0.4 to 6.0% by mass is further preferable, and 0.5 to 5.0% by mass. % Is particularly preferred.

  On the other hand, when gelatin is used as the gel forming agent, the content of the gel forming agent in the hydrogel particles is preferably 15 to 40% by mass, and more preferably 20 to 30% by mass.

  The hydrogel particles of the present invention contain bubbles, but in order to make the hydrogel particles contain bubbles, it is preferable to use a bubble regulator during the production of the hydrogel particles. Various surfactants can be used as the bubble regulator, and at least one selected from anionic surfactants and nonionic surfactants is preferred. Examples of the anionic surfactant include fatty acid salts, phosphate esters, acylated amino acids, sulfosuccinic acids and the like. Examples of the nonionic surfactant include alkyl saccharides and ethylene oxide addition type surfactants. These surfactants can be used singly or in combination of two or more. In particular, anionic surfactants are preferable in terms of stability and safety of bubbles or fineness of bubbles, and fatty acid salts and phosphate esters. Are more preferable, and fatty acid salts are still more preferable. The fatty acid salts are preferably alkali metal salts of fatty acids having 8 to 24 carbon atoms.

  From the viewpoint of obtaining hydrogel particles having a specific gravity of 0.7 to 1.00, the content of the air conditioner in the hydrogel particles of the present invention is preferably 0.5 to 5.0% by mass, and 1.0 to 5%. 0.0 mass% is more preferable.

  The hydrogel particles of the present invention contain, in addition to the above components, water-soluble organic compounds such as saccharides, polyhydric alcohols, water-soluble polymer compounds and water-soluble fragrances described in JP-A No. 2000-126586. Also good.

  The hydrogel particles of the present invention can be produced by preparing a hydrogel containing bubbles by stirring and mixing an aqueous solution containing a gel-forming agent and a bubble regulator, and then producing the particles.

  The stirring method of the aqueous solution containing a gel forming agent and a bubble regulator is not particularly limited, and bubbles can be easily contained in the hydrogel by a conventionally known stirring method. For example, an aqueous solution containing a gel forming agent and a bubble regulator is treated with a normal stirrer or a disperser. By appropriately selecting the amount of the bubble adjusting agent and the processing conditions of the stirring or dispersing machine, bubbles are contained so that the specific gravity of the hydrogel is 1 or less. The specific gravity here refers to the ratio with the density of distilled water at 4 ° C. In addition, the temperature at the time of making a hydrogel contain a bubble is performed at the temperature which hydrogel does not solidify, for example, it carries out between 60 to 100 degreeC, and 70 to 90 degreeC is especially preferable.

  Thus, the hydrogel containing bubbles can be made into particles by a conventionally known method to obtain the hydrogel particles of the present invention. Examples of the particle formation method include a general dropping method and a spraying method.

  The dropping method uses the property that a hydrogel containing bubbles is discharged from a hole and the discharged hydrogel becomes a droplet by its surface tension or interfacial tension, and the droplet is placed in a gas phase such as air or This is a method for producing hydrogel particles by cooling and solidifying in a liquid phase such as cooling oil. In addition, it is preferable to give a vibration to the hydrogel discharged from a hole from a viewpoint of manufacturing a hydrogel particle with a uniform particle diameter.

  The spraying method uses a spray nozzle, sprays hydrogel containing bubbles from the spray nozzle into the gas phase, forms droplets by the surface tension, and cools the droplets in the gas phase to solidify them. A method for producing hydrogel particles.

  In either case of the dropping method or the spraying method, it is preferable that the temperature of the hydrogel containing bubbles at the time of discharge or spraying is set to a temperature not lower than the gelling temperature and not higher than 100 ° C. Further, from the viewpoint that spherical particles having excellent aesthetics can be easily produced, the temperature of the hydrogel containing bubbles is preferably set to a gelation temperature + 10 ° C. or more, and the gelation temperature + 20 ° C. More preferably. The upper limit of this temperature is 100 ° C., which is the boiling point of water. On the other hand, the temperature at which the hydrogel is cooled and granulated is preferably 0 to 30 ° C, more preferably 0 to 20 ° C.

  Moreover, it is preferable to carry out by the fall distance of the hydrogel particle at the time of cooling at 1-10 m, and it is more preferable to carry out at 1-5 m.

  The hydrogel particles of the present invention can contain various other components depending on the application. For example, humectants, cleaning agents, fragrances, pigments, antioxidants, preservatives, and the like can be added. In addition, an ultraviolet absorber, an antibacterial agent, and the like can be added.

  The hydrogel particles of the present invention can be used as a facial cleanser, whole body cleanser, skin cleanser such as bar soap, shampoo, scalp cleanser, dish cleanser, contact lens cleaner, toothpaste, hair restorer, and other massage agents. Can also be used widely.

  In the following examples,% and part are% by mass and part by mass unless otherwise specified.

Example 1
In a 1000 mL separable flask, 30.0 g of agar powder (manufactured by Ina Food Industry; AX-200), which is a gel forming agent made of a natural polymer compound, is weighed, and 870.0 g of ion-exchanged water is charged. While stirring, the gel-forming agent was heated and dissolved at 80 to 90 ° C., and then 96.6 g of a 10% aqueous solution of potassium laurate as a foam regulator and 3.4 g of a 10% aqueous solution of potassium stearate were added to the solution. The total mass was 1000 g.

  Next, this liquid mixture was mixed with an emulsifier [made by Tokushu Kika Co., Ltd., trade name: T. K. Using a homomixer MARK II 2.5 type], the mixture was stirred for 2 minutes at a rotation speed of 10,000 r / min to prepare a hydrogel with bubbles.

  The foamed hydrogel was sprayed at a flow rate of 12 kg / hr into a gas phase at 25 ° C. at a height of 3.4 m from a spray nozzle (Ikeuchi Co., Ltd. empty cone nozzle; K-008). Hydrogel particles were obtained by collecting the particles that settled inside. The average particle diameter of the obtained hydrogel particles was 234 μm, and the specific gravity was 0.96.

Examples 2-4
Hydrogel particles were obtained by the preparation method shown in Example 1 except that the type of the air conditioner was changed as shown in Table 1.

Comparative Example 1
Hydrogel particles were obtained by the preparation method shown in Example 1 except that the type and amount of the air conditioner were changed.

Comparative Example 2
Hydrogel particles were obtained by the preparation method shown in Example 1 except that no air bubble modifier was added.

  The average particle diameter and particle specific gravity of the hydrogel particles obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were measured by the above methods. Moreover, the washing | cleaning property and the rinse-off property were evaluated by the following method. These results are shown in Table 1.

<Evaluation method for detergency>
(1) Preparation of cleaning liquid 10% of potassium laurate (Wako Pure Chemical Industries), 20% each of hydrogel particles obtained in Examples 1 to 4 or Comparative Examples 1 to 2, and 70% ion-exchanged water uniformly at room temperature Dissolve and disperse.

(2) Evaluation of detergency A model sebum having the composition shown below in which carbon black is dispersed is prepared, 20 mg thereof is applied in a circle of Φ25 mm on artificial leather, 200 mg of the above-mentioned cleaning solution is dropped on the applied portion, and massaged 20 times. It was washed and rinsed with tap water and air dried.
・ Model sebum composition (model sebum)
Squalane (manufactured by Wako Pure Chemical Industries, Ltd.) 9.0 parts Myristyl myristate (trade name EXCEPAR MY-M, manufactured by Kao Corporation) 24.0 parts Cotton seed oil (manufactured by Kanto Chemical Co., Ltd.) 47.0 parts Cholesterol (Wako Pure Chemical Industries, Ltd.) Industrial Co., Ltd.) 2.0 parts cholesterol palmitate (Tokyo Chemical Industry Co., Ltd.) 2.0 parts Lauric acid (trade name Lunac L-98, manufactured by Kao Corporation) 0.2 parts Myristic acid (trade name Lunac MY-98, 2.5 parts palmitic acid (trade name Lunac P-95, manufactured by Kao Corporation) 6.0 parts stearic acid (trade name Lunac S-98, manufactured by Kao Corporation) 0.9 parts oleic acid (Wako Pure Chemicals) Kogyo Co., Ltd.) 6.4 parts Total 100 parts (Marker)
5 parts of carbon black (Mitsubishi Chemical Corporation).

The chromaticity (Lab) of the arm at each time point before the washing procedure (before applying model sebum), before washing (after applying model sebum), and after washing (after rinsing and air drying) is measured with a color difference meter CR-200 ( The color difference before and after the cleaning was measured and displayed with a color difference meter.
Then, the washing rate of the model sebum was calculated according to the following formula from the color difference before treatment and before washing, and the color difference before and after washing, and the washing rate of 10% aqueous solution of potassium laurate (no hydrogel particles) was set to 1. Relative values were evaluated against the following criteria.

Washing rate (%) = (1− (color difference after washing / color difference before washing)) × 100
Evaluation criteria for detergency x: Detergency <detergency without hydrogel particles Δ: Detergency without hydrogel particles <detergency <[detergency without hydrogel particles x 1.1]
○: [Washing rate without hydrogel particles × 1.1] ≦ Washing rate <Evaluation method of flushability>
0.1 g of hydrogel particle aqueous solution prepared in 20% aqueous solution was left on black artificial leather. After the black artificial leather was tilted at 10 °, 2 g of ion-exchanged water was dropped with a dropper. The state of dripping was observed with a Nikon stereo microscope (SM2-2T), and the number of hydrogel particles remaining in the visual field (about 1 cm) after 10 seconds of dropping was counted to determine the washability on the basis of the following criteria.
×: 10 or more hydrogel particles were observed in the visual field Δ: 1-9 hydrogel particles were observed in the visual field ○: No hydrogel particles were observed in the visual field

* 1 MAP-115K: 30% aqueous solution of potassium monoalkyl phosphate having an alkyl chain length of alkyl group composition C11 / C13 / C15 = 48/31/21 (mass ratio)
* 2 Mass% with respect to the total amount of hydrogel particles

The hydrogel particles of the present invention are excellent in physical detergency, and by making the hydrogel particles have a specific gravity equal to or lower than that of water or tears, the rinse properties are very good in rinsing water and tears, and the detergent composition Etc. are useful.

Claims (5)

A method for producing hydrogel particles containing bubbles, having a specific gravity of 0.7 to 1.00 and an average particle size of 50 to 500 μm ,
It is a production method in which an aqueous solution containing a gel forming agent and a bubble regulator is mixed by stirring to contain bubbles, sprayed at a temperature not lower than the gelation temperature and not higher than 100 ° C., and cooled.
The gel-forming agent is agar, the bubble regulator is at least one selected from an anionic surfactant and a nonionic surfactant, and the content of the gel-forming agent in the hydrogel particles is 0. The manufacturing method of hydrogel particle which is 0.1-8.0 mass%, and content of the said bubble regulator in the said hydrogel particle is 0.5-5.0 mass% . The manufacturing method of the hydrogel particle of Claim 1 which performs cooling between 0-30 degreeC. The method for producing hydrogel particles according to claim 1 or 2 , wherein the gelation temperature of the hydrogel is 30 ° C or higher. The method for producing hydrogel particles according to any one of claims 1 to 3, wherein the bubble regulator is a fatty acid salt. The said hydrogel particle is a scrub agent, The manufacturing method of the hydrogel particle in any one of Claims 1-4.