JP2014201588A - Medicine-impregnated sheet with controlled zeta potential and face mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medicine-impregnated sheet of high adhesion, and a face mask prepared using the same.SOLUTION: This invention relates to a medicine-impregnated sheet in which an absolute value of a surface zeta potential on at least one face is in the range of 35 mV or more and 250 mV or less, and a face mask prepared using the same.

Description

  The present invention relates to a chemical liquid impregnated sheet having a controlled zeta potential and a face mask using the same. Specifically, the zeta potential is controlled to an appropriate value, so that the skin adhesion at the time of wearing on the human body is exceptionally high and the liquid retention property of the chemical is excellent, It relates to the used face mask.

  In recent years, sheets and face masks impregnated with medicinal solutions are expanding as anti-aging products for particularly busy modern women as health and beauty awareness increase. The materials used for these sheets and face masks are cellulosic fibers represented by cupra long fibers, cotton and rayon, and their nonwoven fabrics are typical examples. The reason why cellulose-based non-woven fabrics are preferably used is that they have a higher hydrophilicity than synthetic non-woven fabrics, so the liquid retention of chemicals is high, the liquids are good when worn, and the time during which they can be kept wet when worn For example, it is long and easy to penetrate the skin into the skin.

Cupra filament nonwoven Among cellulosic fiber nonwoven fabric (Asahi Kasei Fibers Corp. Bemliese ^TM), because the degree of crystallinity in cellulose fibers is small, high liquid retention chemical solution, high flexibility when wet , It is excellent in following ability and adhesion (wearing to the skin) at the time of wearing. Moreover, since it is a nonwoven fabric consisting of continuous long fibers and the cross-sectional shape is a round cross section, it is used as a particularly suitable material as a gentle material per skin when worn.
However, as a chemical solution impregnated sheet for face masks and cosmetic sheets, in recent years, there has been a demand for a sheet that exhibits adhesiveness following the curved surface and unevenness of the face when worn. In particular, high adhesion without peeling has been demanded even during movements from the initial wear to removal and changes in conversation and facial expressions.

  Therefore, as an improvement of the beauty sheet for obtaining high adhesion, a face pack using a nonwoven fabric layer composed of nanofibers made of a thermoplastic resin having a single fiber diameter of 1 to 500 nm as a sticking surface has been proposed ( See Patent Document 1 below). However, since the nanofiber described in Patent Document 1 is composed of a thermoplastic resin, it is inferior in flexibility when wet, and in reality, it has not reached a sufficiently satisfactory level from the viewpoint of adhesion. It was.

  In Patent Document 2 below, an ultrafine fiber layer containing 10% by mass or more of ultrafine fibers having a fineness of 0.5 dtex or less is located on one or both surfaces of the hydrophilic fiber layer containing 50% by mass or more of hydrophilic fibers. In addition, a skin covering sheet for impregnating cosmetics having an ultrafine fiber layer as a contact surface with the skin and a face mask impregnated with liquid cosmetics have been proposed. However, Patent Document 2 discloses cellulosic fibers such as rayon and pulp as hydrophilic fibers, but the fibers specifically used in the examples are heated as ultrafine fibers having a fineness of 0.5 dtex or less. Since it is a split type composite fiber made of a plastic resin, it is inferior in flexibility when wet as in Patent Document 1, and has not reached a sufficiently satisfactory level from the viewpoint of adhesion.

Japanese Patent No. 4816312 Japanese Patent No. 3944526

  In view of such circumstances, an object of the present invention is to provide a highly adhesive chemical liquid impregnated sheet that cannot be achieved with a conventional nonwoven fabric when attached and a face mask using the same. Furthermore, it is providing the chemical | medical solution impregnation sheet | seat excellent in the liquid retention performance of a chemical | medical solution, and the sustained release of an active ingredient, and a face mask using the same.

The inventors of the present invention are not sufficient to make the fiber diameter finer in order to develop the performance having the adhesion, liquid retention, and component sustained release properties required for chemical liquid impregnated sheets, especially beauty sheets and face masks. As a result of intensive studies on the fact that it is necessary to utilize the fact that the skin has a potential and the potential acts on the skin, the present invention has been achieved.
That is, the present invention provides the following inventions.

(1) A chemical solution-impregnated sheet, wherein the absolute value of at least one surface zeta potential is in the range of 35 mV to 250 mV.
(2) It is composed of a structure composed of fibers, and has an average fiber diameter of at least 0.01 μm and not more than 50 μm and a porosity of 50% to 90% at least in the range where the surface zeta potential is in the above range. The chemical liquid impregnated sheet according to the above item 1.
(3) The chemical solution impregnated sheet as described in (2) above, wherein the structure comprises a cellulose-based non-woven fabric.
(4) The chemical liquid impregnated sheet according to any one of the above items 1 to 3, wherein 100 to 2000 parts by weight of the chemical liquid is impregnated with respect to 100 parts by weight of the sheet.
(5) A face mask comprising the chemical liquid impregnated sheet according to any one of items 1 to 4 above.

  The present invention is a chemical solution impregnated sheet in which the zeta potential is controlled to an appropriate value and a face mask using the same, and the adhesion at the time of wearing is remarkably higher than that of a conventional product, and the liquid retention property of the chemical solution and the skin Enables product design with excellent chemical penetration.

Hereinafter, the present invention will be described in detail.
The present invention is the chemical solution impregnated sheet, wherein the absolute value of the surface zeta potential is in the range of 35 mV to 250 mV. More preferably, it is the range of 40 mV or more and 200 mV or less. By controlling within this range, it is possible to control the adhesion when brought into contact with the skin and the permeability of the drug solution into the skin.
For example, a healthy skin surface is said to exhibit a zeta potential of about −40 mV. In contrast, when a compound having a cationic substituent, for example, a compound having a quaternary ammonium group or the like is introduced to the surface of the sheet of the present invention by physical adsorption or surface reaction, the skin and the surface of the present invention are statically separated. This is preferable because adhesion is increased through electrical interaction.

  On the other hand, when a suitable amount of a compound having a strong anionic substituent, for example, a p-benzenesulfonic acid group having a sulfone group or an alkylsulfonic acid group, is introduced by a surface reaction, the surface zeta potential is controlled to a large negative value. be able to. When a large surface potential difference is provided between the surface in contact with the skin and the skin, the same effect as that when an electric field is applied to the surface of the skin appears. According to Japanese Patent Laid-Open No. 2002-291909, it is said that when a negative DC electric field of about 500 mV is applied to the surface of the skin, a remarkable effect appears in the recovery of the skin barrier function. When a zeta potential of about 100 mV, for example, as an absolute value is applied to the skin contact surface of the chemical liquid impregnated sheet of the present invention, the same effect can be exhibited.

  Further, when the chemical liquid impregnated in the chemical liquid-impregnated sheet contains an ionic compound having a charge, the compound itself is provided by providing a potential difference (electric field) between the sheet and the skin. Alternatively, a compound that interacts with the compound can be delivered to the skin, that is, a pumping action by an electric field gradient can be imparted, and the medicinal solution permeability to the skin can be increased, which is sometimes effective. In other words, by controlling the zeta potential within a predetermined range, in addition to the function of the sheet having high adhesion to the skin defined in the present invention, the conventional product has been observed such as promoting the penetration of the impregnating chemical into the skin. It becomes possible to provide a plurality of effects that were not achieved. The effect may be appropriately selected according to the needs required for the chemical-impregnated sheet, and a zeta potential suitable for the required effect may be set, and is not particularly limited to the compounds and substituents described above.

  In the chemical liquid impregnated sheet of the present invention, the surface having the surface zeta potential does not have to be both surfaces, and may be at least one surface. In the case of one side, the product may be designed so that the surface having the surface zeta potential is the side in contact with the skin when worn on the human body.

  The chemical liquid impregnated sheet of the present invention is preferably a structure composed of fibers, and the average fiber diameter of the surface in contact with the skin is preferably 0.01 μm or more and 50 μm or less. More preferably, it is 0.02 μm or more and 30 μm or less. When the thickness is 50 μm or more, the surface area becomes small and it becomes difficult to apply a zeta potential, and the adhesion cannot be improved anymore. On the other hand, since 0.01 micrometer or less is very fine, production is difficult, and it is hard to say that it is preferable from economical viewpoint, and is not realistic.

  Moreover, it is preferable that the porosity of the chemical | medical solution impregnation sheet | seat of this invention needs to be 50 to 90%, More preferably, it is 60 to 85%. If it is less than 50%, the liquid or cosmetic liquid retainability is poor, and the sheet becomes rigid, so that the followability is impaired when it comes into contact with the skin. On the other hand, if it exceeds 90%, a large amount of chemical solution can be impregnated, but since it is too soft, handling becomes difficult.

  In the present invention, the structure composed of fibers is suitably a nonwoven fabric containing cellulosic fibers, from the viewpoints of drug solution retention and sustained release. The proportion of cellulosic fibers is preferably 30 wt% to 100 wt%, more preferably 50 wt% to 100 wt%. If it is less than 30 wt%, the retention of the chemical solution becomes insufficient, and it becomes difficult to hold the desired chemical solution on the skin for a certain period of time.

  The cellulose-based fiber material of the present invention is pure cellulose pulp, rayon, cupra, lyocell, etc. made of cellulose softwood pulp, hardwood pulp, cotton-derived pulp, hemp-derived pulp, kenaf-derived pulp, bamboo-derived pulp, bagasse-derived pulp, etc. In addition to various cellulose fibers, it is selected from cellulose derivative fibers such as cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, carboxymethylcellulose, carboxyethylcellulose, nitrocellulose, and methylcellulose. These fiber diameters are not particularly limited, and the fiber length is not limited at all, and short fibers (fiber length 2 mm to 100 mm) and long fibers can be used. Of these, cupra, lyocell, etc. The long fiber made of regenerated cellulose is particularly preferable because it has a low crystallinity and thus has a high liquid-retaining property, high flexibility when wet, and excellent followability when worn.

  You may mix another fiber in the range which does not inhibit chemical | medical solution containing immersion. For example, in order to improve the strength, fibers including polyethylene fibers, polypropylene fibers, nylon fibers, polyketone fibers, polyester fibers and the like may be used.

  The material for the skin surface of the chemical-impregnated sheet of the present invention is not particularly limited. However, inclusion of cellulose fibers facilitates the introduction of a charged substituent and is convenient for controlling the zeta potential. As methods for introducing a substituent having a charge, two methods, physical adsorption and surface reaction, can be mentioned. In the case of the physical adsorption method, utilizing the fact that the cellulose fiber surface usually has a zeta potential of about −30 mV, a compound having a cationic substituent is physically adsorbed on the surface and immobilized. In addition to the interaction between charges, the motive force of adsorption also acts as an attractive interaction due to hydrogen bonding. Therefore, if a strong cationic compound is successfully adsorbed, a positive charge of up to about +100 mV can be introduced by this method. Is possible. Further, a negative surface potential can be imparted by physically adsorbing a negatively charged compound in the same manner on the positively charged surface. By making full use of such an alternate adsorption technique, the surface of the fine cellulose fiber can be controlled in a zeta potential range of −150 mV to +150 mV.

  In such a physical adsorption method, a cationic or anionic compound is adsorbed and immobilized on the surface of fine cellulose fibers. Specifically, amine base, quaternary ammonium base, carboxylate base, sulfonate group, phosphoric acid An ionic compound having a base or nitrate group in the molecule, more specifically, anionic surface activity such as alkyl sulfate ester salt, polyoxyethylene alkyl sulfate ester salt, alkylbenzene sulfonate, α-olefin sulfonate And cationic surfactants such as agents, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, benzalkonium chloride, and ionic water-soluble polymers such as cationized polyvinyl alcohol and anionized polyvinyl alcohol. Is limited to these Not to.

  Next, a surface reaction method as a second method for introducing a charged substituent will be described. Since the cellulose fiber contained in the chemical liquid impregnated sheet of the present invention contains a large number of hydroxyl groups on the surface, a compound having a charge is introduced by a chemical reaction utilizing the reactivity of the hydroxyl groups. As the chemical reaction at this time, it is possible to use all chemical reactions represented by reactions to hydroxyl groups, that is, esterification, etherification, silicateization, urethanization, carboxylation by TEMPO oxidation, and the like. In this method, since the structure of the compound can be designed freely, for example, surface reaction with a compound (for example, para-benzenesulfonate isocyanate) designed with a strong ionic substituent located slightly away from the reaction site. Thus, it is possible to introduce a large surface potential as an absolute value, and the surface zeta potential of the contact surface with the skin of the chemical liquid impregnated sheet of the present invention can be controlled in the range of −250 mV to +250 mV. By such a surface reaction method, an amine base or a quaternary ammonium base can be introduced as a cationic group, and a carboxylate base, a sulfonate group, a phosphate base, or a nitrate base can be introduced as an anion group.

In the chemical solution impregnated sheet of the present invention, those having a total weight per unit area of 10 g / m ² or more and 200 g / m ² or less are preferably used. If it is less than 10 g / m ² , the mechanical strength cannot be obtained, and the handleability when worn on the skin surface is deteriorated. When it exceeds 200 g / m ² , the flexibility when wet is inferior, and a high adhesion feeling cannot be obtained. Preferably, at 15 g / m ² or more 150 g / m ² or less, more preferably 20 g / m ² or more 120 g / m ² or less.

  The film thickness of the sheet used for the chemical liquid impregnated sheet of the present invention is preferably 20 μm or more and 800 μm or less. If the film thickness is less than 20 μm, the mechanical strength is small and the handleability is poor. If it exceeds 800 μm, the followability is deteriorated and the adhesion performance is impaired. In order to use suitably, Preferably they are 30 micrometers or more and 600 micrometers or less, More preferably, they are 50 micrometers or more and 500 micrometers or less.

  In the chemical liquid impregnated sheet of the present invention, although depending on the purpose of use of the chemical liquid impregnated sheet, it is preferable that 100 to 2000 parts by weight of the chemical liquid is impregnated with respect to 100 parts by weight of the sheet. The chemicals targeted by the present invention include cosmetic chemicals and medical chemicals. That is, in the present invention, the chemical liquid-impregnated sheet means a generic name of a cosmetic liquid-impregnated sheet for cosmetic purposes such as a face mask, and a medical liquid-impregnated sheet for medical purposes such as a wound dressing or a sustained-release medicine patch.

Hereinafter, the present invention will be described in more detail with reference to examples. The main measured values of physical properties were measured by the following methods.
(1) Zeta potential evaluation method The surface zeta potential of the sheet surface was measured using Zeta Sizer Nano ZS ^TM manufactured by Spectris. As measurement conditions, flat cell ZEN1020 is used as a measurement cell, 1 to 1.5 ml of potassium chloride 0.01 mol / L aqueous solution is used as a measurement solvent, latex particles charged negatively or titanium oxide charged positively is used as tracer particles. Particles were used. The measurement was performed at 25 ° C.

(2) Average fiber diameter With respect to the sheet surface, observation at 3 locations at random is carried out with a scanning electron microscope (SEM) at a magnification equivalent to 1000 to 10,000 times. With respect to the obtained SEM image, a line is drawn in the horizontal direction and the vertical direction with respect to the screen, and the fiber diameter of the fiber intersecting the line is measured from the enlarged image, and the number of intersecting fibers and the fiber diameter of each fiber are counted. In this way, the number average fiber diameter is calculated using two series of measurement results for one image. Further, the number average fiber diameter is calculated in the same manner for the other two extracted SEM images, and the results for a total of three images are averaged to obtain the average fiber diameter of the target sample.

(3) Weight per unit area The weight per unit area was calculated according to JIS P 8124.
(4) Thickness measuring method The humidity-controlled nonwoven fabric structure was measured with an automatic micrometer manufactured by Hibridge Corporation under an atmosphere of room temperature of 20 ° C. and humidity of 65% RH.

(5) Face mask wearing feeling evaluation method A face mask impregnated with 1000 parts by weight of a moisturizing liquid (Kanebo Cosmillion Co., Ltd. Ururi) is prepared for 100 parts by weight of a sheet punched into a certain face shape. Ten female panelists in their 40s were allowed to wear, and sensory evaluation was performed for the feeling of closeness and handling at the time of wearing, as well as the moisture retention after 3 hours after wearing. In addition, each evaluation was evaluated on a 5-point scale, and the average value of 10 people (rounded off after the decimal point) was calculated.
5 points: Excellent adhesion, handling and moisture retention.
4 points: Good adhesion, handleability and moisture retention.
3 points: There is no problem in adhesion, handleability, and moisture retention.
2 points: Slightly inferior in adhesion, handling and moisture retention.
1 point: Adhesion feeling, handleability and moisture retention are poor.

Example 1
Prepare a 0.5 wt% aqueous solution of polydiallyldimethylammonium chloride (PDADMAC, manufactured by Nitto Bo Medical, PAS-H-10L, average molecular weight 200,000), which is a water-soluble polymer containing a quaternary ammonium salt, and prepare a cupra rayon nonwoven fabric. (Made by Asahi Kasei Fibers, trade name: Benrize ^™ SE603, basis weight 60 g / m ² , film thickness 400 μm, density 0.15 g / cm ³ , average fiber diameter 13 μm) cut into 30 cm square size in a stainless steel pad 20 Dipped for a minute. Next, after washing with pure water for 1 hour, drying was performed with a drum dryer apparatus at 130 ° C. When the weight after drying was weighed, a 0.9 wt% weight increase due to the adsorption of PDADMAC was observed.

It was +41 mV when the surface zeta potential of the obtained nonwoven fabric sheet was measured.
This sheet was punched into a certain face shape, and a panel was used for sensory evaluation using 100 parts by weight of the sheet impregnated with 1000 parts by weight of moisturizing liquid (Kanebo Cosmilion Co., Ltd. Ururi). When provided, the feeling of adhesion at the time of wearing, handleability, and moisture retention after wearing were the results shown in Table 1. It was a good face mask that greatly improved the feeling of adhesion and maintained the moisture retention after wearing.

(Example 2)
After preparing a 3.0 wt% aqueous solution of polydiallyldimethylammonium chloride (PDADMAC, manufactured by Nittobo Medical, PAS-H-10L, average molecular weight 200,000), which is a water-soluble polymer containing a quaternary ammonium salt, The same operation as in Example 1 was performed. A weight increase of 2.3 wt% due to the adsorption of PDADMAC was observed.
When the surface zeta potential of the obtained nonwoven fabric sheet was measured, it was +58 mV, and when this was subjected to sensory evaluation, the adhesion feeling at the time of wearing, the handleability, and the moisture retention after wearing were the results shown in Table 1. . It was a good face mask in which the feeling of adhesion and moisture retention after wearing were continuously maintained.

(Comparative Example 1)
When the surface zeta potential was measured independently for a cupra rayon nonwoven fabric (Asahi Kasei Fibers, trade name: Benrize ^™ SE603, basis weight 60 g / m ² , film thickness 400 μm, density 0.15 g / cm ³ , average fiber diameter 13 μm), It was −30 mV.
When this sheet was punched into a certain face shape and subjected to sensory evaluation by a paneler in the same manner as in Example 1, the adhesion feeling at the time of wearing, handleability, and moisture retention after wearing were as shown in Table 1. became. It has been found that the face mask has insufficient adhesion and does not retain moisture retention, i.e., it is difficult for medicinal components to penetrate into the skin.

  According to the present invention, it is possible to provide a chemical liquid-impregnated sheet that has remarkably high adhesion at the time of wearing, and excellent in liquid retention of cosmetics and chemical liquid permeation into the skin, and a face mask using the same.

Claims (5)

  A chemical solution-impregnated sheet, wherein the absolute value of the surface zeta potential on at least one side is in the range of 35 mV to 250 mV.   It is composed of a structure composed of fibers, and at least the surface zeta potential in the above range has an average fiber diameter of 0.01 μm or more and 50 μm or less, and a porosity of 50% to 90%. Item 2. A chemical-impregnated sheet according to Item 1.   The chemical structure impregnated sheet according to claim 2, wherein the structure includes a nonwoven fabric of cellulosic fibers.   The chemical liquid impregnated sheet according to any one of claims 1 to 3, wherein 100 to 2000 parts by weight of the chemical liquid is impregnated with respect to 100 parts by weight of the sheet.   A face mask comprising the chemical liquid impregnated sheet according to any one of claims 1 to 4.