JP2012080913A - Silk sponge body for skin care - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silk sponge body for skin care, which has a sufficient scrub effect being hypoallergenic to skin and keeps the skin clean.SOLUTION: The silk sponge body for skin care is constituted by allowing a sponge body formed of a silk fibroin porous material as a base material, and allowing the silk fibroin porous material to include a porous layer and a film layer which is arranged only on one surface. The silk fibroin porous material is the material which coexists with an additive to be selected from a group including silk fibroin, an organic solvent, amino acid, and aliphatic carboxylic acid and is frozen and kept. The silk sponge body for skin care is suitable as a scrub item by impregnation with facial cleanser.

Description

  The present invention relates to a silk sponge body for skin care, and more particularly to a silk sponge body for skin care that is simple to manufacture, has low irritation to skin, has a sufficient scrubbing effect, and can keep the skin clean.

When removing makeup, washing face, and taking a bath, it is not easy to cleanly remove dust held in pores, skin grooves, oil stains, waste and sebum on the skin surface, old keratin, etc. with ordinary detergents. In addition, since the stratum corneum on the skin surface is bound by an intercellular adhesion protein such as desmosome, there are cases where it does not easily peel off, and it is necessary to apply some external force.
Conventionally, various powders have been used as a scrub agent in addition to cleansing agents such as face-wash creams and soaps, for scrubbing to remove old stratum corneum along with dirt and to make the skin beautiful. It was. Pumice may be used especially for keratin care such as heels and elbows. Examples of these scrubbing agents include crystalline cellulose powder, apricot, walnut, peach, pulverized fruit such as plum (see Patent Document 1), minerals such as talc and silica, polyethylene, and vinyl chloride. Synthetic fine powders such as the above have been used to scrape and remove dirt and aging stratum corneum and lift them up.
In addition, a product having a soft feeling with a puffed sponge body mainly composed of a synthetic resin as a carrier for these cleaning and scrubbing agents has also been provided.
However, emphasis was placed on the removal of dirt and the like, and the effect on the skin was rarely considered. In order to provide a low-irritant material for skin while having an effect of removing dirt and keratin, as shown in Patent Document 2, the strength is lowered when a sufficient granule strength is blended with a detergent or the like during granulation. There are also proposals to accelerate the disintegration of the scrub agent to reduce irritation to the skin, and proposals to solve this point with a gel-like scrub agent as seen in Patent Documents 3-5.
However, no product has yet been provided that is simple to manufacture, hypoallergenic to the skin, has a sufficient scrubbing effect and keeps the skin clean.

Japanese Unexamined Patent Publication No. 7-025723 JP 2007-261947 A JP-A-6-321728 Japanese Patent Laid-Open No. 9-143046 JP 2003-292419 A

  The present invention has been made to solve the above-mentioned problems, and is a silk for skin care that is easy to manufacture, has low irritation to the skin, has a sufficient scrubbing effect, and can keep the skin clean. An object is to provide a sponge body.

  As a result of intensive studies to achieve the object, the present inventors have found that the object can be achieved by using a sponge body made of a silk fibroin porous material as a base material. It came to complete.

That is, the present invention provides the following inventions.
(1) A silk sponge body for skin care based on a sponge body made of a silk fibroin porous body.
(2) The silk sponge for skin care according to (1), wherein the silk fibroin porous body has a porous layer and a film layer only on one surface thereof.
(3) The porous layer has a water absorption rate of 20 to 30 μl / s and / or an evaporation rate of 0.008 to 0.2 g / m ² · s, and the film layer has a water absorption rate of 0.1. The silk sponge body for skin care according to (2), having a viscosity of ˜3.5 μl / s and / or an evaporation rate of 0.03 to 0.07 g / m ² · s.
(4) The silk fibroin porous material is a porous material produced by freezing and holding in the presence of silk fibroin and an additive selected from the group consisting of organic solvents, amino acids and aliphatic carboxylic acids. The silk sponge body for skin care according to any one of (1) to (3).
(5) The silk sponge body for skin care according to any one of (1) to (4), wherein the pore diameter of the silk fibroin porous body is 30 μm or more and 200 μm or less.
(6) The silk sponge body for skin care according to any one of (1) to (5), wherein the silk fibroin porous body is impregnated with a facial cleanser.
(7) The silk sponge body for skin care according to any one of (1) to (6), which is a scrub product.

  The silk sponge body for skin care of the present invention is easy to manufacture, has low irritation to the skin, has a sufficient scrubbing effect, and can keep the skin clean. In addition, it has high safety, is easy to handle, has sufficient strength, and is biodegradable, thereby reducing the environmental burden.

It is a figure which shows the various shapes of the silk sponge body for skin care of this invention.

The silk sponge body for skin care of the present invention is a silk sponge body for skin care based on a sponge body made of a silk fibroin porous body.
The silk fibroin in the present invention refers to the protein main component of silk thread made from rabbits and the like. As the silk fibroin raw material, sericin is removed from cocoons, raw silk, swarf, raw silk, etc. by removing a sericin by a normal scouring method such as a sodium carbonate method, a soap-soda method or an enzyme scouring method.

  The silk fibroin porous material used in the present invention can be produced by freezing and holding in the presence of silk fibroin and an additive selected from the group consisting of an organic solvent, an amino acid and an aliphatic carboxylic acid. For example, silk fibroin is dissolved in a copper ethylenediamine aqueous solution, a lithium bromide aqueous solution, a calcium chloride-alcohol aqueous solution at room temperature or warmed, dissolved, desalted by dialysis, etc., and purified by centrifugation or the like (concentration 0.1). 1 to 4% by mass of a water-soluble organic substance such as dimethylformamide and acetic acid is added to -40% by mass, preferably 3 to 8% by mass) After melting, it is manufactured by washing and removing the additive.

  The pore size (pore diameter: pore diameter) in the silk fibroin porous material used in the present invention is preferably 30 μm or more and 200 μm or less. The pore diameter can be controlled to some extent by adjusting the mixing ratio of the silk fibroin and the additive and the conditions of the cooling process at the time of freezing as described above, and is determined according to the application.

The silk sponge body of the present invention can be sterilized at high pressure, and can be used after sterilization as necessary. The sterilization method is not limited to high-pressure sterilization, and gas sterilization, electron beam, or gamma ray sterilization can be used as necessary.
Furthermore, the silk sponge body of the present invention can be punched into a certain shape with Thomson or the like after the sponge body is produced, but by changing the form of the mold as a container when producing the silk sponge body, As shown in FIG. 1, in addition to the cube (a), the rectangular parallelepiped (b), and the oval (c), it can be made into a spherical shape, etc., and punched out like other sponge bodies It is not necessary to use a process, a polishing process, etc., and it is excellent in productivity.

The silk sponge body of the present invention may have a porous layer and a film layer only on one surface thereof.
When the silk sponge body is produced as described above, the center part of the silk porous body is a porous layer, but the vicinity in contact with the container is a film layer having few pores. The film layer preferably has pores with an area ratio of 10% or less on the surface, and the porous layer preferably has a surface with pores with an area ratio of 50 to 98%. Further, even when the film layer has fine pores, the fine pores having a pore diameter of 0.5 μm or more are 20 pieces / mm ² or less (preferably 10 pieces / mm ² or less). It is preferable that it does not have a hole.
The porous layer has a water absorption rate of 20-30 μl / s and / or an evaporation rate of 0.008-0.2 g / m ² · s, and the film layer has a water absorption rate of 0.1-3. 5 μl / s and / or the evaporation rate is preferably 0.03 to 0.07 g / m ² · s.

Each item measured in the above and examples can be defined and measured as follows.
The area ratio, number and diameter of the pores can be defined as follows.
The structure of the silk fibroin porous material was observed using a scanning electron microscope. The scanning electron microscope was measured using a Philips XL30-FEG in a low vacuum non-deposition mode and an acceleration voltage of 10 kV. The structure of the porous body is obtained by observing the cross section of the film layer, the porous layer, and the porous body, and using the image analysis software ImageJ (manufactured by National Institutes of Health, USA) for the obtained scanning electron micrograph. By processing, the pore area ratio, number and diameter were measured. In addition, the measurement was performed 5 times and the average value was calculated.
The water absorption rate can be defined as follows.
The silk fibroin porous material was immersed in pure water for 24 hours to contain water, and the wet weight was measured (Wa). The porous body was freeze-dried and sufficiently dried, and the dry weight of the porous body was measured (Wb). From these values, the water absorption rate of the porous body was calculated according to the following equation.
Water absorption (%) = (Wa−Wb) × 100 / Wb
The water absorption rate can be defined as follows.
100 μl of pure water was dropped on the silk fibroin porous material (porous layer or film layer), and the time until absorption was measured. The water absorption rate is a value calculated from the following equation using the measured time. The measurement was performed 5 times, and the average value was taken as the water absorption rate.
Water absorption rate (μl / s) = pure amount of pure water / time required for water absorption The evaporation rate can be defined as follows.
Silk fibroin porous material (porous layer or film layer) is immersed in pure water for 48 hours and completely absorbed, then in a constant temperature and humidity chamber set at a temperature of 40 ° C. and a relative humidity of 50%. The weight was measured every minute until 10 minutes passed, and every 2 minutes after 10 minutes, and the change was regarded as a change in the amount of water evaporated. The evaporation rate is a value calculated from the following equation from the change in the evaporation amount from 1 minute to 30 minutes after standing.
Evaporation rate (g / m ² · s) = (Change in evaporation) / Porous material surface area

The thickness of the film layer is preferably 10 to 100 μm.
Moreover, in order to have a film layer only on such one surface, the silk porous body obtained above may be sliced so that the porous layer and the film layer have a desired thickness.
In this way, by making the outer surface of the silk fibroin porous body more dense than the skin contact surface, the effect of delaying the evaporation of the essence, etc., the retention efficiency of the essence on the skin contact surface, and the moisture retention of the skin surface Has the effect of enhancing the properties.

Silk fibroin used in the present invention is blended in cosmetics and has been used for a long time as a hair care product such as champulins, has a high biocompatibility, and has a track record as a safe material without skin irritation and sensitization. It has a high reputation as a skin care product, and its product value is high as a high-quality image. Furthermore, silk fibroin has an advantage that it is a material that can contribute to environmental problems that have been emphasized in recent years because of its biodegradability.
The silk fibroin used in the present invention has both hydrophilic and lipophilic properties, easily retains an oily cleansing agent and a hydrophilic cleaning agent, and has good foaming with soaps. Accordingly, the skin care cosmetics that can be impregnated in the silk sponge body used in the present invention are not particularly limited, and known scrub cosmetics are used. In addition, it is possible to use a skin care agent such as a conventional cleaning agent or cosmetic liquid soaked in a sponge body, and a facial cleanser is particularly preferable.
The silk sponge for skin care of the present invention is weaker than a synthetic resin sponge, cellulose sponge, sponge sponge, etc., and even when rubbed strongly, the sponge base material itself is less likely to collapse and damage the skin. Therefore, dirt present on fine irregularities of the skin due to the porous nature of the sponge body can be removed with little damage to the skin.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
(Preparation of silk fibroin solution)
Silk fibroin aqueous solution is prepared by dissolving silk fibroin powder (KB Selen, trade name: “Fibroin IM”) in 9M lithium bromide aqueous solution, removing insoluble matter by centrifugation, and then dialysis against ultrapure water. Obtained by repeating. The obtained silk fibroin aqueous solution was air-dried in a dialysis tube and concentrated. An acetic acid aqueous solution was added to the concentrate as an additive to prepare a silk fibroin solution having a silk fibroin concentration of 5 mass% and an acetic acid concentration of 2 mass%.
(Manufacture of porous material)
The silk fibroin solution was poured into a mold (inside size; 80 mm × 40 mm × 4 mm) made of an aluminum plate, placed in a low temperature thermostatic bath (NCB-3300 manufactured by EYELA), and allowed to stand at −1 ° C. for 10 hours. Thereafter, it was frozen under the following conditions.
(Freezing condition)
Freezing is performed by cooling a low-temperature thermostat bath to -1 ° C in advance, putting a mold containing a silk fibroin solution in the low-temperature thermostat bath, precooling for 30 hours, and then up to -20 ° C at a rate of 3 ° C / hour. Cooled and held at that temperature for 5 hours.
The frozen sample was returned to room temperature by natural thawing, then removed from the mold, immersed in ultrapure water, and the acetic acid used was removed by exchanging the ultrapure water twice a day for 3 days.

  The structure of the obtained silk fibroin porous material was observed using a scanning electron microscope. The scanning electron microscope was measured using a Philips XL30-FEG in a low vacuum non-deposition mode and an acceleration voltage of 10 kV. In addition, the structure of the silk fibroin porous body includes the surface of the porous body (film layer), the cross section including the film layer and the porous layer, and the inside (porous layer) exposed by cutting the porous body. Observed.

  Moreover, the average pore diameter was calculated by image-processing the obtained scanning electron micrograph using image analysis software ImageJ (made by the National Institutes of Health). The average pore diameter was obtained by taking five scanning electron micrographs from the produced porous material, and further taking five scanning electron micrographs from the porous material produced on different days. The average value of the measurement results obtained by measuring a single scanning electron micrograph is shown. The average pore diameter is shown in Table 1 together with the results of Examples 2 and 3 described below.

Example 2
In Example 1, a silk sponge body was obtained in the same manner as in Example 1 except that the precooling time was 30 minutes.

Example 3
In Example 1, the silk fibroin concentration was 1% by mass, the additive was aspartic acid, the precooling time was 30 minutes, the precooling temperature was −5 ° C., and the cooling rate was 1 ° C./hour. A silk sponge body was obtained in the same manner as in 1.

Example 4
Table 3 shows the results of evaluation of the three types of sponges of Examples 1 to 3 by the strength of rubbing the sponge body with water and rubbing it on the upper arm skin surface during normal face washing or bathing.
The touch was evaluated as follows.

○: The texture is soft and there is no irritation to the skin. △: The touch feels a little hard, and there is a slight irritation.

Example 5
Using the sponge body produced in Example 2, cellulose sponge (manufactured by Toray), urethane sponge (general commercial sponge), 0.5 parts by mass of carbon powder is kneaded with 10 parts by mass of petroleum jelly in the upper arm inner skin. Table 3 shows the results obtained by applying the paste-like material as a contaminant, impregnating the sponge body with water, and evaluating the strength by rubbing on the upper arm skin surface during normal face washing or bathing. The evaluation criteria were as follows.

Degree of skin (redness): ◎: None, ○: Slight erythema is observed, △: Redness remains, ×: Erythema, degree of dirt that causes scratches (remaining carbon in skin groove) Condition): ◎: No residual dirt is observed in the hide and skin, ○: Conspicuous dirt does not remain, but some residual dirt is observed, △: Carbon remains in the skin groove Yes, x: How to remove the dirt that remains partially (the condition of the vaseline remaining in the crevice): ◎: Neither the dermis nor the crevice remains, the skin is wet, ○ : Vaseline remains in the hides and skin grooves, but partially repels water, △: Remains in the groove area, x: The fall is sparse and partially remains, and the entire skin is watered Repel.

Example 6
About the sponge body of Examples 1-3, the water absorption rate, the water absorption rate, and the evaporation rate were measured according to the said method. The results are shown in Table 4.

  The silk sponge body for skin care of the present invention is easy to manufacture, has low irritation to the skin, has a sufficient scrubbing effect, and can keep the skin clean. In addition, it has high safety, is easy to handle, has sufficient strength, and is biodegradable, thereby reducing the environmental burden. Therefore, it can be widely applied for health care in the cosmetics / esthetic field, and is particularly suitable as a scrub product.

Claims (7)

  A silk sponge body for skin care based on a sponge body made of a silk fibroin porous body.   The silk sponge body for skin care according to claim 1, wherein the silk fibroin porous body has a porous layer and a film layer only on one surface thereof. The porous layer has a water absorption rate of 20-30 μl / s and / or an evaporation rate of 0.08-0.2 g / m ² · s, and the film layer has a water absorption rate of 0.1-3. The silk sponge body for skin care according to claim ² , having an evaporation rate of 5 µl / s and / or 0.03 to 0.07 g / m ² · s.   2. The silk fibroin porous material is a porous material produced by freezing and holding together with silk fibroin and an additive selected from the group consisting of an organic solvent, an amino acid and an aliphatic carboxylic acid. A silk sponge body for skin care according to any one of -3.   The silk sponge body for skin care according to any one of claims 1 to 4, wherein the silk fibroin porous body has a pore diameter of 30 µm or more and 200 µm or less.   The silk sponge body for skin care according to any one of claims 1 to 5, wherein the silk fibroin porous body is impregnated with a facial cleanser.   It is a scrub article, The silk sponge body for skin care in any one of Claims 1-6.