EP1925231A1

EP1925231A1 - Skin care implement and method for manufacture thereof

Info

Publication number: EP1925231A1
Application number: EP06782988A
Authority: EP
Inventors: Masanobu Takeda; Takahiro Hasui; Naomi Matsumoto
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2005-08-26
Filing date: 2006-08-24
Publication date: 2008-05-28
Also published as: CN101296633A; TW200716806A; US20090145507A1; TWI379023B; EP1925231A4; KR20080037049A; WO2007023887A1

Abstract

An object of the present invention is to prove a skin care goods that is low irritant to the skin and superior in wiping efficiency of the dirt in the sulucus cutis and pores of the skin. Thus, the present invention provides a skin care goods of a pile fabric, the pile fabric comprising pile yarns of nanofibers of thermoplastic polymer having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex and ground yarns.

Description

TECHNICAL FIELD

The present invention relates to a skin care goods utilizing nanofiber. The term "skin care" used in the present invention is to make the entire skin of the body clean and refreshed, and the "skin care goods" is a goods generally used for that purpose.

[BACKGROUND ART]

It is very important to remove wastes such as cosmetics and sebum effectively during face wash for preservation and promotion of skin health and for prevention, for example, of acne and pimple. However, it is quite difficult to remove the wastes present in the depth of the wrinkles and pores of the skin simply by normal face wash. In addition, although "waterproof cosmetic preparations" and "waterproof sunscreens", which were developed along with the recent progress of production technology, have advantages in durability and effectiveness, they also have a problem in removal during face wash and cleansing. There are many cleansing lotions developed for removal of these cosmetic preparations, but it is still practically difficult even now to remove the cosmetic preparations and sebum stains in the pores even with an cleansing oil that is regarded most effective in cleansing action. In addition, there are recently in the market many cosmetic preparations that are applied not only on the face but also on the entire body, especially on the legs and the breast for attractiveness, and these products too have the same problem.
On the other hand, generally known is use of a skin care goods employing ultrafine fiber, for example partially during face wash, as a means of increasing cleaning efficiency.
For example, a skin care goods employing an ultrafine fiber having a fineness of 0.001 to 1 dtex is disclosed (e.g., Patent Document 1).
However, the cleansing effect thereof is based on the fine foams generated by a soap solution passing through the fine spaces among the ultrafine fibers (see, e.g., Patent Document 1, paragraph number 0020), and the goods is still insufficient in removing highly persistent cosmetic preparation and others completely.
Also disclosed is a skin care goods that wipes off dirt and old cuticle directly with an ultrafine fiber having a fineness of 0.001 to 1 dtex (e.g., Patent Documents 2 and 3). However, such a method of wiping off dirt and old horny layer by rubbing the skin directly with an ultrafine fiber having a fineness of 0.001 to 1 dtex imposes excessive stimulus and friction on the skin, causing concern about possibly skin troubles such as chromatosis, cuticle thickening, as well as frictional melanoderma in some cases.
As described above, there is still no skin care goods that is low irritative to the skin and superior in wiping efficiency of the dirt in the depth of the pores, and thus, there is an urgent need currently for prompt development thereof.
Patent Document 1: Japanese Unexamined Patent Publication No. 2004-332149
Patent Document 2: Japanese Unexamined Patent Publication No. 2004-329628
Patent Document 3: Japanese Registered Utility Model No. 3100954
Patent Document 4: Japanese Unexamined Patent Publication No. 2005-330637

SUMMARY OF THE INVENTION

[Problems to be Solved by the Invention]

An object of the present invention, which was made under the circumstances above to solve the problems above in traditional technology, is to prove a skin care goods that is low irritant to the skin and superior in wiping efficiency of the dirt in the sulcus cutis and pores of the skin.

[Means to Solve the Problems]

The present invention, which solved the problems above, has the following aspects:

1. A skin care goods of a pile fabric, the pile fabric comprising pile yarns of nanofibers of thermoplastic polymer having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex and ground yarns.

2. The skin care goods according to Aspect 1, wherein the thermoplastic polymer is nylon.

3. The skin care goods according to Aspect 1 or 2, wherein the number-average monofilament fineness of the nanofiber is 4×10^-4 dtex or less.

4. The skin care goods according to any one of Aspects 1 to 3, wherein the pile yarn is a bundle of nanofiber filaments.

5. The skin care goods according to any one of Aspects 1 to 4, wherein the monofilament fineness of the ground yarn is larger than 8×10^-4 dtex.

6. The skin care goods according to any one of aspects 1 to 5, wherein the monofilament fineness of the ground yarn is larger than 1×10^-1 dtex.

7. The skin care goods according to any one of Aspects 1 to 6, wherein the length of the pile is in the range of 1 to 10 mm.

8. The skin care goods according to any one of Aspects 1 to 7, wherein the length of the pile is in the range of 2 to 5 mm.

9. The skin care goods according to any one of Claims 1 to 8, wherein the tips of the pile filaments are cut.

10. The skin care goods according to any one of Aspects 1 to 9, wherein the skin care goods has a sheet shape and the double faced piles.

11. The skin care goods according to Aspect 10, wherein the pile fabrics with the single faced piles are laminated to each other.

12. A method of producing the skin care goods according to any one of Aspects 1 to 11, comprising a step of forming a nanofiber having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex by treating a pile fabric having pile yarns of polymer alloy fibers consisting of sea and island components with a liquid dissolving the sea component but not dissolving the ground yarn.

ADVANTAGEOUS EFFECT OF THE INVENTION

As will be described below, it is possible according to the present invention to provide a skin care goods that is superior in the wiping efficiency of removing dirt on the skin surface and also in the depth of the sulcus cutis and pores of the skin and yet low irritant to the skin. In addition, the skin care goods utilizing nanofiber according to the present invention also provides the user with comfortableness. The skin care goods according to the present invention is also superior in dimensional stability and texture and favorable in hand, compared to the fabrics only of nanofiber.

BREIF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic crosssectional view illustrating an example of the woven or knitted fabric constituting the skin care goods according to the present invention.
Figure 2 is a TEM micrograph showing the cross section of a polymer alloy fiber, nanofiber precursor.
Figure 3 is SEM micrograph showing the surface of a bundle of nylon 6 nanofiber filaments.
Figure 4 is a surface SEM micrograph showing a bundle of nylon 6 nanofiber filaments when wetted and swollen with water.
Figure 5 is a crosssectional micrograph of a pile yarn of a bundle of nylon 6 nanofiber filaments bonded to an artificial skin (cow leather).
Figure 6 is a SEM micrograph showing a pile yarn of a bundle of nylon 6 nanofiber filaments capturing dirt (a captured dirt particle shown in circle).
Figure 7 is a schematic view illustrating a bundle of nanofiber filaments being swollen by absorption of water and deformed by external force and capturing and removing a dirt in the depth of a pore while enclosing the dirt.
Figure 8 is a schematic view comparing the cut pile (a) and the loop pile (b) of a pile yarn of a bundle of nanofiber filaments.

Explanation of Numerals

1: Loop pile yarn
2: Ground yarn
3: Cut pile yarn
4: Cow leather
5: Nanofiber pile yarn
6: Nanofiber bundle under standard condition
7: Nanofiber bundle under wet codition
8: Nanofiber bundle during deformation
9: Skin
10: Dirt particle
11: Pile fabric ground (basic structure)
12: Island (domain)
13: Sea (matrix)

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The thermoplastic polymer for the nanofibers constituting the pile yarn for the skin care goods according to the present invention may be, for example, polyester, polyamide, polyolefin, polyphenylene sulfide (PPS) or the like. Among them, polyamides such as nylon 6, which have strong hydrogen bonds, are preferable for preservation of the nanofiber bundle shape, as will be described below.
It is important that the pile yarn is made of nanofibers in the skin care goods according to the present invention. The nanofiber, when used, reaches into the depth of the sulcus cutis and pores of the skin and allows removal of the dirt therein, differently from skin care goods made of conventional ultrafine fibers (microfibers). It is probably because the nanofiber has a smaller fiber diameter, and also a small geometrical moment of inertia, an indicator of the deformability of nanofiber, of 1.0×10^-32 to 2.5×10^-3, which is smaller than that of conventional ultrafine fibers, and thus, higher fiber flexibility. Thus, the pile yarn, which contains nanofiber filaments that are more deformable and dispersible when in contact with the skin, reaches together densely into the depth of sulcus cutis and pores of the skin, removing fine dirt therein (see Figure 5).
In addition, the nanofiber prohibits localized concentration of stress and also of friction on the skin significantly and enlargement of the pores.
Further, the nanofiber also allows preparation of fine foams having a diameter of 1×10¹ µm or less and adsorption of the dirt in the depth of the pores on the fine foams. The foam is smaller and more fine than that made with conventional ultrafine fibers reported for example in Patent Document 3 described above.
On the other hand, with a conventional ultrafine fiber, it is not possible to make a sufficient number of the filaments fit into the sulcus cutis and pores of the skin, because of its larger monofilament fineness. Because such a fiber does not give a bundle as described below and is thus resistant to deformation along the sulcus cutis and pores of the skin, it cannot remove the fine dirt therein. In addition, the less deforming ultrafine fiber often causes stress concentration on the skin, damaging the horny layer and applying excessive friction on the skin.
The fineness of the nanofiber is 1×10^-8 to 2.2×10^-3 dtex, as number-average monofilament fineness (corresponding to a monofilament diameter of 1 to 500 nm in the case of nylon 6), and preferably 4×10^-4 dtex or less (corresponding to a monofilament diameter of 211 nm, in the case of nylon 6 having a density of 1.14 g/cm³), more preferably 2×10^-4 dtex or less (monofilament diameter of 149 nm or less in the case of nylon 6), still more preferably 1×10^-4 dtex or less (monofilament diameter of 106 nm or less in the case of nylon 6), and still more preferably, 8×10^-6 to 6×10^-5 dtex (monofilament diameter of 30 to 82 nm in the case of nylon 6). It is possible advantageously to make the nanofiber fit into the depth of the sulcus cutis and pores of the skin easily and remove the dirt therein, by reducing the number-average monofilament fineness of the nanofiber to 2.2×10^-3 dtex or less. On the other hand, when the fineness is smaller than 1×10^-8 dtex, the nanofiber and also its pile yarn become unsatisfactory in strength.
The nanofiber preferably forms a bundle of filaments by aggregation under standard condition. The nanofiber bundle swells by absorption of liquid (see Figure 4) and is flattened when in contact with the skin, with the surface nanofiber filaments deforming or dispersing themselves along the wrinklessulcus cutis and pores of the skin. The deformation and dispersion of the nanofiber filaments leads to breakdown of larger dirt and takes the dirt deep into the nanofiber bundle. Fine dirt present in the sulcus cutis and pores of the skin are collected deep into the bundle during high contact of the dispersed nanofiber filaments with the depth the sulcus cutis and pores of the skin (see Figures 6 and 7). The removed dirt is protected from re-deposition on the skin, as it is taken deep into the nanofiber bundle.
Such a nanofiber is obtained, for example, by the following method:
Namely, it is produced by preparing a polymer alloy consisting of the sea (matrix) of an easily soluble polymer and islands (domains) of a hardly soluble polymer by using two or more polymers different in solubility in solvents, and spinning and solidifying the polymer alloy into fiber by cooling. After drawing and heat treatment as needed, the polymer alloy fiber obtained is treated with a solvent for removal of the easily soluble polymer preferably to an extent of 99.9% or more, to give nanofiber.
In the method above, the diameter of the nanofiber is determined mostly by the size of the islands (domains) in the nanofiber precursor polymer alloy fiber.
The size of the island (domain) may be controlled by adjustment of polymer blending, and intense blending in a kneading extruder, static mixer or the like is desirable.
The combination of polymers also exerts significant influence on the size of the island (domain). The island (domain) polymer and the sea (matrix) polymer are preferably incompatible to each other, to make the island (domain) more circular in shape. However, it is difficult to disperse the island (domain) polymer ultrafinely simply by using a combination of different incompatible polymers. Thus, the polymer combination is preferably selected by using solubility parameter (SP value) as an indicator. The SP value is a parameter reflecting the cohesive force of substance, which is defined by (energy of vaporization/molar volume)^1/2. A difference of two polymer SP values of 1 to 9 (MJ/m³)^1/2 is favorable both for the circularity of the island (domain) and ultrafine dispersion of the islands by incompatibilization. For example, nylon 6 (N6) and polyethylene terephthalate (PET), which have a SP value difference of about 6 (MJ/m³)^1/2, is a favorable combination, but N6 and polyethylene (PE), which have a SP value difference of about 11 (MJ/m³)^1/2, is an example of unfavorable combination.
The melt viscosity also influenced on the size of the island (domain). It is favorable to make the melt viscosity of the island-component polymer smaller than that of the sea-component polymer for production of nanofiber, because it facilitates deformation of the island-component polymer by shearing force and thus fine dispersion of the island-component polymer. However, excessive reduction of the viscosity of the island-component polymer makes the polymer more like the sea-component polymer, prohibiting increase in the blend rate in the entire fiber, and thus, the viscosity of the island-component polymer is preferably 1/10 or more of the viscosity of the sea-component polymer.
The solvent dissolving the sea (matrix) polymer but hardly dissolving the island (domain) polymer is, for example, an alkaline solution, an acidic solution, an organic solvent, a supercritical fluid, or the like. For example, in the case of a combination of nylon and polyester, Nylon is hardly soluble, while polyester, easily soluble in alkaline solution.
The raw material for the ground yarn constituting the pile fabric in the skin care goods according to the present invention may be a synthetic or a natural fiber, but, if the polymer alloy fiber is converted into the pile yarn by sea-removing treatment after a pile fabrics is prepared, the raw material is preferably a material undissolved in the sea-removing treatment, more preferably the same as the nanofiber used as pile, from the points of freedom in designing for example of dyeing and also of the texture and touch feeling during use of the resulting goods.
In addition, the water- or oil-absorbing property thereof is preferably is not larger than that of the nanofiber for the pile yarn. It is thus possible to make the nanofiber pile filaments used as the skin-wiping layer hold aqueous or oil cleansing lotion or facial wash more efficiently.
The monofilament fineness of the ground yarn is preferably more than 8×10^-4 dtex, more preferably 1×10^-1 dtex or more. It is possible to improve the dimensional stability and the texture without sacrifice of the nanofiber wiping efficiency, by using such a ground yarn.
Favorable shapes of the pile fabric include woven and knit fabrics. Typical examples of the knit fabrics include circular knitted fabric, tricot fabric, double raschel fabric, and the like.
The length of the pile in pile fabric is preferably in the range of 1 to 10 mm, more preferably in the range of 2 to 5 mm. It is possible to make the nanofiber pile filaments more flexible and provide the filaments with favorable wiping efficiency and comfortable texture when wet, by making the length 1 mm or more. It is also possible to prevent deterioration in texture by fall down of the pile filaments, by making the length not more than 10 mm.
The nanofiber pile filaments in the pile fabiric of the skin care goods according to the present invention are favorably cut pile. In this way, it is possible to increase the degree of freedom in movement of the nanofiber in pile yarn, to make the tip of the nanofiber fit into the sulcus cutis and pores of the skin, and to increase the wiping efficiency of the yarn. It is further possible to spread the stress applied to the skin widely during wiping and obtain comfortable texture under wet condition.(see Figure 8).
When a conventional microfibers is used for the pile yarn, the cut pile often gave unfavorable irritate to the skin by contact of the tip of the fiber to the skin. For that reason, the cut of pile filaments at the tip in skin care goods could be conceivable only when such a nanofiber is used.
The possible shapes of the skin care goods according to the present invention include towel, mitten, gloves, finger cot, and the like. The towel shape is preferable, because it allows modification of its use method according to the preference of the user. In addition, shapes covering the hand or the finger such as mitten, gloves and finger cot are also favorable, from the point of easiness in handling.
In addition, double faced pile fabricis a favorable shape of the skin care goods according to the present invention. It is possible, by double faced pile fabric containing nanofiber pile yarns, to make the user use the skin care gooods according to the present invention without recognition of the front or rear face of it and improve the handling efficiency and the impression of use. In processing into such a shape, the pile filaments may be formed directly on both faces of the pile fabric, but, for preparation of a skin care goods with high pile density, it is preferable to laminated two single faced pile fabrics. For example, a method of sewing the edge of the fabric or a method of bonding the pile fabrics with an adhesive agent such as urethane adhesive may be used in laminating the pile fabrics.
Alternatively, a medium such as net that accelerates foaming of facial wash may be used in combination for more favorable foaming of the facial wash.
Yet alternatively, a cushion material covered with a pile fabric containing nanofiber pile yarns is also favorable, and the shape thereof may be mitten or gloves.
Then, the method of producing a skin care goods according to the present invention is a method of producing the skin care goods according to the present invention, comprising a step of treating a pile fabric having pile yarns of polymer alloy fibers consisting of sea and island components with a liquid dissolving the sea component but not dissolving the ground yarn and forming nanofiber filaments having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex. As described above, the method of subjecting a polymer alloy fiber to a sea-removing treatment is favorable for forming nanofiber filaments, and it is possible to obtain good form stability and comfortable texture of a pile fabricss even after sea-component removal, by carrying out the sea-removing treatment with a liquid dissolving the sea component but not dissolving the ground yarn, i.e., by using a ground yarn resistant to solubilization in the sea-removing treatment.

EXAMPLES

[Measuring method]

(1) Weight-average molecular weight of polylactic acid

A sample was dissolved in chloroform, and tetrahydrofuran was added thereto, to give a test solution. It was analyzed by using a gel-permeation chromatographic (GPC) apparatus Waters 2690 manufactured by Waters at 25°C to give weight-average molecular weight as polystyrene.

(2) Number-average monofilament fineness of nanofiber

Five pile filaments were withdrawn at random from a region of 5 cmx5 cm in dimension, and each ultrathin section thereof in the filament crosssectional direction was prepared and observed under a transmission electron microscope (TEM) (H-7100FA, manufactured by Hitachi Ltd., magnification: 100,000).
From the TEM micrograph of the fiber crosssectional section by using image processing software (WINROOF) the monofilament diameters of 300 or more filaments chosen at random in the same cross section respectively of the five pile yarns, i.e., a total of 1,500 cross sections, were determined, and the simple average thereof obtained was used as the number-average monofilament diameter of the nanofiber. A monofilament fineness was calculated from the monofilament diameter according to the following Formula: $Number average monofilament fineness (dtex) = (d \times D^{2} \times π / 4) \times 10^{- 8}$

Wherein, d: density (g/cm³), and D: number-average monofilament diameter (nm).

(3) Evaluation of dirt-wiping efficiency A

The artificial skin used for evaluation was an expanded polyethylene sheet ("Toraypef"®, manufactured by Toray Industries, Inc.). A highly waterproof cosmetic preparation (eye liner fluid, manufactured by Shiseido Co., Ltd.) was applied thereon in a circular shape of 1 cm in diameter and dried at 20±2°C and 65±2% RH for 12 hours.
The test piece was cut into a piece of 6 cm in length and 8 cm in width; a cleansing lotion (white cleansing water, manufactured by Kose Cosmeport Corp.) was impregnated into the test piece in an amount of 2.6 times of the mass of the test piece; and the test piece was bonded to a silicone rubber plate (6 cm in length ×7 cm in width × 1 cm in thickness).
The artificial skin in the area coated with the cosmetic preparation was rubbed for wiping reciprocally five times with the test piece under a loaded pressure of 0.5 cN/mm² (300 g/2.5 cm²), a velocity of 2 cm/s, and a wiping width of 2 cm. Removal of dirt after the wiping operation was evaluated by visual examination and rated in the following five categories.

5: All dirt in the sulcus cutis of artificial skin removed
4: Some dirt remaining in the sulcus cutis of artificial skin
3: Significant dirt remaining in the sulcus cutis of artificial skin
2: Some dirt remaining in the sulcus cutisand also on the surface of artificial skin
1: Significant dirt remaining in the sulcus cutisand also on the surface of artificial skin

(4) Evaluation of dirt-wiping efficiency B

A highly waterproof cosmetic preparation (eye liner fluid, manufactured by Shiseido Co., Ltd.) was applied in an area of 0.5 cm × 2 cm on the internal arm and dried thereon under normal temperature and normal humidity for 30 minutes.
The test piece was cut into a piece of 6 cm in length and 8 cm in width; a cleansing lotion (white cleansing water, manufactured by Kose Cosmeport Corp.) was impregnated into the test piece in an amount 2.6 times of the mass of the test piece; and the test piece was wound around a silicone rubber rod (diameter: approximately 8 mm), and the arm area previously coated with the cosmetic preparation was wiped ten times in a fixed direction.
Removal of dirt after the wiping operation was evaluated under a microscope (VH-6300C manufactured by Keyence Corp., magnification: 300) and rated in the following five categories.

5: All dirt in the depth of the sulcus cutisand pores of the skin removed
4: Some dirt remaining in the depth of the sulcus cutis and pores of the skin
3: Significant dirt remaining in the depth of the sulcus cutisand pores of the skin
2: Some dirt remaining in the depth of the sulcus cutis and pores and also on the surface of the skin
1: Significant dirt remaining in the depth of the sulcus cutis and pores and also on the surface of the skin

(5) Irritation test

An agar sheet prepared by dissolving agar (pure agar, manufactured by Sanada Co., Ltd.) and solidifying the solution by cooling was used as the artificial skin for evaluation.
The test piece was cut into a piece of 6 cm in length and 8 cm in width; water was impregnated into the sheet in an amount of 2.6 times of the mass of the test piece; the test piece was wound around a silicone rubber rod (diameter: approximately 8 mm), and the surface of the agar sheet was wiped ten times in a fixed direction.
The scratching on the agar sheet surface after wiping operation was observed by visual examination and rated in the following five categories.

5: No scratching of the surface of the agar
4: Some scratching of the surface of the agar
3: scratching of the surface of the agar
2: Deep scratching of the surface of the agar
1: Many deep scratchings of the surface of the agar

(6) Evaluation of foaming efficiency

A polyethylene net of 10 cm × 10 cm in dimension (8 mesh) was used as the medium accelerating foaming, and the net was enclosed tightly with the test piece of 15 cm×15 cm, and the opening was sewn with a cotton yarn.
A face wash solution (concentration: 20 mass %, temperature 37°C) was impregnated therein in an amount of 30% of the mass of the test piece, and the test piece was beaten a hundred times with a pestle for foaming. The surface shape of the foam obtained was observed under a microscope (VH-6300 C manufactured by Keyence Corp., magnification: 300 times).

(7) Monitoring test (face wash puff application)

The test piece was cut into a piece of 6 cm in length and 8 cm in width, and a cleansing lotion (white cleansing water, manufactured by Kose Cosmeport Corp.) was impregnated into the test piece in an amount of 2.6 times of the test piece mass.
A makeup cleansing test by using the test piece was carried out with 50 females in 20's to 50's of age, and the efficiency of removal of cosmetic preparation, texture, skin irritation, convenience in use, and others were studied by questionnaire survey.

(8) Monitoring test (facial washcloth application)

The test piece was cut into a piece of 6 cm in length and 8 cm in width; and the test piece was then wetted with a facial wash ("Dove® moisture foam F" manufactured by Unilever Japan Co., Ltd.) and then allowed to foam.
A monitoring test by using the test piece was carried out with 50 females in 20's to 50's of age, and the efficiency of removal of cosmetic preparation, texture, skin irritation, convenience in use, and others were studied by questionnaire survey.

[Example 1]

(Polymer alloy fiber)

Nylon 6 (N6) having a melt viscosity 212 Pa·s (262°C, at a shear rate of 121.6 sec^-1) and a melting point of 220°C (45 mass %) and poly-L-lactic acid having a weight-average molecular weight of 120,000, a melt viscosity of 30 Pa·s (240°C, shear rate: 2432sec^-1), a melting point of 170°C, and an optical purity of 99.5% or more (55 mass %) were weighed separately, and fed separately to a biaxial extrusion kneader described below in detail, where they are melted and blended at 220°C, to give polymer alloy chips.

Screw shape : Unidirectional complete-gearing double-start thread screw
Screw diameter: 37 mm,
Effective length: 1670 mm, L/D=45.1
Blending region length: extrusion side from 1/3 of screw effective length
Vent: 2 positions.

The polymer alloy chip obtained was supplied to a spinning machine, molten at 230°C therein, filtered through a metal nonwoven fabric having a critical filtration diameter of 15 µm in the spin block at a spinning temperature of 230°C, and melt-spun out of nozzles having a diameter of 0.3 mm and a length of 0.55 mm at a nozzle plate temperature 215°C. The extruded filaments were solidified by cooling in the range of 1 m in length with cooling air at 20°C, applied with an oil by an oil supply guide placed 1.8 m below the nozzles, withdrawn at a spinning rate of 3000 m/minute, and then, drawn under the condition of a drawing temperature of 90°C at a drawing rate of 1.5 and a heat set temperature of 130°C.
The multifilament of polymer alloy fiber thus obtained had a size of 133 dtex/48 filaments, a strength of 3.6 cN/dtex, an elongation of 40%, and a Percentage Uster of 0.7%. Observation of the crosssectional section of the polymer alloy fiber obtained under TEM revealed that it had a sea/island structure containing poly-L-lactic acid as the sea (matrix) and N6 as islands (domains) and the islands (domains) were dispersed very finely at a number-average diameter of 110 nm.

(Pile yarn)

The multifilament of the polymer alloy fiber was used as the pile yarn.

(Ground yarn)

A nylon 6 multifilament having a total fineness of 75 dtex of 24 filaments (monofilament fineness: 3.1 dtex) was used as the ground yarn.

(Knitting)

A loop-pile knitted fabric having a pile length of 2.2 mm was prepared in a sinker-pile single circular knitting machine by using the multifilament of the polymer alloy fibers as the pile yarn and also as the ground yarn.

(Skin caregoods)

The pile knitted fabric was treated with 1% aqueous sodium hydroxide solution at a temperature of 98°C and a bath ratio of 1:100 for 1 hour by immersion, removing 99.9% or more of the polylactic acid in the polymer alloy fiber by hydrolysis, and thus, giving a skin care goods of a pile fabric having pile yarns of N6 nanofiber bundles and ground yarns of N6 multifilaments.
The fineness distribution of the N6 nanofiber, as determined from the 1,500 samples in measurement (1), was in the range of 1×10^-8 to 4×10^-4 dtex, and the number-average monofilament fineness thereof was 1×10^-4 dtex.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency tests A and B. In the irritation test, the skin care goods was extremely low irritative. It also gave favorable results in all test items in the monitoring test. In addition in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Example 2]

(Polymer alloy fiber)

A multifilament of polymer alloy fiber similar to that in Example 1 was prepared.

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

The yarn the same as that used in Example 1 was used as the ground yarn.

(Knitting)

A pile knitted fabric was prepared in a similar manner to Example 1 by using the pile yarn and the ground yarn.

(Skin care goods)

The pile knitted fabric was subjected to sea-removing treatment in a similar manner to Example 1 and the tip of the loop pile was cut by emery processing, to give a skin care goods.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed on the surface. It also gave favorable results in all test items in the monitoring test. In particular, there were many opinions that the texture of the goods was more favorable in the questionnaire survey, compared to the results in Example 1, because of cut pile. In the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Example 3]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber was used as the pile yarn.

(Ground yarn)

A nylon 6 multifilament having a total fineness of 110 dtex of 24 filaments (monofilament fineness: 4.6 dtex) was used as the ground yarn.

(Knitting)

A pile knitted fabric was prepared in a similar manner to Example 1, except that the ground yarn above was used.

(Skin caregoods)

The pile knitted fabric was subjected to sea-removing treatment in a similar manner to Example 1, to give a skin care goods.
The fineness distribution of the N6 nanofiber, as determined from the 1,500 samples in measurement (1), was in the range of 1×10^-8 to 4×10^-4 dtex, and the number-average monofilament fineness thereof was 1×10^-4 dtex.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency test A and B. In the irritation test, the skin care goods was extremely low irritative. It also gave favorable results in all test items in the monitoring test. In particular, the monofilament of ground yarn was thicker and rigidder than that of the skin care goods prepared in Example 1, and thus, there were many opinions that the goods was superior in dimensional stability and more favorable in the convenience in use in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Example 4]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

(Knitting)

(Skin care goods)

The pile knitted fabric was subjected to sea-removing treatment similarly to that used in Example 1.

(The processings above are the same as those in Example 3.)

Then, the tip of the loop pile was cut by emery processing, to give a skin care goods.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed on the surface. It also gave favorable results in all test items in the monitoring test. In particular, because of cut pile, there were many opinions that the texture was "very comfortable" than in Example 3 in the questionnaire survey. In particular, the monofilament of ground yarn was thicker and rigidder than that of the skin care goods prepared in Example 2, and thus, there were many opinions that the goods was superior in dimensional stability and more favorable in the convenience in use in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Examples 5 and 6]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

A nylon 6 multifilament having a total fineness of 110 dtex of 24 filaments (monofilament fineness: 4.6 dtex) was used as the ground yarn (similarly to Example 3).

(Knitting)

A double raschel fabric having a gap between the two knitted fabrics at 6.0 mm was prepared by using the pile and ground yarns in a double raschel knitting machine. The double raschel knitted fabric was cut into two fabrics in the region corresponding to a pile length of 1:3, to give a cut pile knitted fabric having a pile length of 1.5 mm and a cut pile knitted fabric having a pile length of 4.5 mm.

(Skin care goods)

The two kinds of pile knitted fabrics were respectively subjected to sea-removing treatment similarly to that described in Example 1, to give skin care goods. The goods having a pile length of 1.5 mm was prepared in Example 5, while that having a pile length of 4.5 mm was prepared in Example 6.
Each of the N6 nanofiber used in Examples 5 and 6 had a fineness distribution, as determined from 1,500 samples in measurement (1), in the range of 1×10^-8 to 4×10^-4 dtex, and the number-average monofilament fineness thereof was 1×10^-4 dtex.
Each of the samples obtained showed favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed on the surface in both Examples. Also in the monitoring tests, the samples of both Examples gave favorable result in all test items. In particular in Example 6, there were more favorable opinions on texture in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Examples 7 and 8]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

(Knitting)

A double raschel fabric having a gap between the two knitted fabrics at 6.0 mm was prepared by using the pile and ground yarns in a double raschel knitting machine. The double raschel fabric was cut into two fabrics in the region corresponding to a pile length of 5:7, to give a cut pile knitted fabric having a pile length of 2.5 mm and a cut pile knitted fabric having a pile length of 3.5 mm.
Both in Examples 7 and 8, the fineness distribution of the N6 nanofiber, as determined from the 1,500 samples in measurement (1), was in the range of 1×10^-8 to 4×10^-4 dtex, and the number-average monofilament fineness thereof was 1×10^-4 dtex.

(Skin care goods)

The two kinds of pile knitted fabrics were respectively subjected to sea-removing treatment similarly to that described in Example 1, to give skin care goods. The goods having a pile length of 2.5 mm was prepared in Example 7, while that having a pile length of 3.5 mm was prepared in Example 8.
Each of the samples obtained showed favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed on the surface in both Examples. Also in the monitoring test, the samples of both Examples gave favorable results in all test items. In particular in both Examples, there were more favorable opinions on texture in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Example 9]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

The yarn identical with that used in Example 1 was used as the ground yarn.

(Knitting)

A pile knitted fabric was prepared in a similar manner to Example 1 by using the pile and ground yarns.

(Skin care goods)

The pile knitted fabric was subjected to sea-removing treatment similarly to that used in Example 1, and then, the tip of the loop pile was cut by raising in emery processing, to give a skin care goods.

(The processings above are the same as those in Example 2.)

Two test pieces of the cut pile knitted fabric cut to a dimension suitable were prepared respectively, and sewn with a cotton thread with the ground yarn faces thereof facing each other, to give a skin care goods with the double faced piles.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed. It also gave favorable results in all test items in the monitoring test. Because two sheets were laminated, there were many opinions that the goods was superior in hand and convenience in use in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Example 10]

(Polymer alloy fiber)

(Pile yarn)

The multifilament of polymer alloy fiber above was used as the pile yarn.

(Ground yarn)

The yarn identical with that used in Example 1 was used as the ground yarn.

(Knitting)

(Skin caregoods)

The pile knitted fabric was subjected to sea-removing treatment similarly to that used in Example 1, and then, the tip of the loop pile was cut by emery processing, to give a skin care goods.

(The processings above are the same as those in Example 2.)

Two cut pile knitted fabrics obtained were piled on and bonded to each other with their ground yarn faces facing each other; and the ground yarn faces were bonded to each other with a urethane-based adhesive (Tyforce® 865HV, manufactured by Dainippon Ink and Chemicals, Inc.) in the dotted pattern in a coating amount of approximately 4 g/m², to give a skin care goods with double faced pile.
The skin care goods obtained gave favorable results both in the dirt-wiping efficiency tests A and B. Favorably in the irritation test, there was almost no scratching observed. It also gave favorable results in all test items in the monitoring test. Because two sheets were laminated, there were many opinions that the goods was superior in hand and convenience in use in the questionnaire survey. Alternatively in the foaming efficiency test, generation of fine foams having a diameter of 10 µm or less was observed.

[Comparative Example 1]

A commercially available microfiber facial washcloth (removal towel, available from Cogit Co., Ltd., number-average monofilament fineness: 0.22 dtex) was evaluated.
In the dirt-wiping efficiency test, the washcloth was found to be unsatisfactory both in test items A and B, compared to the skin care device according to the present invention. Also in the irritation test, it showed strong scratching action. In addition, it was not found favorable compared to the skin care goods according to the present invention in each test item of the monitoring test. Further in the foaming efficiency test, there were observed only large foams having a diameter of about 100 µm to 1 mm.

[Comparative Example 2]

A commercially available microfiber-based facial washcloth (Preri Cuticle-Refreshing Cloth®, manufactured by Lucky Corporation) was evaluated.
In the dirt-wiping efficiency test, the washcloth was found to be unsatisfactory both in test items A and B, compared to the skin care goods according to the present invention. Also in the irritation test, it showed strong scratching action. In addition, it was not found favorable compared to the skin care goods according to the present invention in each test item of the monitoring test. In particular, there were many opinions that it was more irritant and stimulating to the skin and caused tingle after use. Also in the foaming efficiency test, there were observed only large foams having a diameter of about 100 µm to 1 mm.

[Comparative Example 3]

A commercially available microfiber-based facial washcloth (Toraysee® facial washcloth, manufactured by Toray Industries, Inc., number-average monofilament fineness: 0.08 dtex) was evaluated.
In the foaming efficiency test, there were observed fine foams having a diameter of 1 to 20 µm, and the size of the foams was not even.

[Table 1]

	Example 1	Example 2	Example 3	Example 4
Pile length	2.2mm	2.2mm	2.2mm	2.2mm
Pile shape	Loop	Cut	Loop	Cut
Ground varr dtex(dexitex)x f(filament	75× 24	←	110× 24	←
Configuration	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth
Dirt-wiping effeciency test A	4	5	4	5
Dirt-wiping effeciency test R	4	5	4	5
Irritation test	4	5	4	5

[Table 2]

	Example 5	Example 6	Example 7	Example 8
Pile length	1.5mm	4.5mm	2.5mm	3.5mm
Pile shape	Cut	Cut	Cut	Cut
Ground varr dtex(dexitex)x f(filament	110× 24	←	110× 24	←
Configuration	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth
Dirt-wiping effeciency test A	5	5	5	5
Dirt-wiping effeciency test R	5	5	5	5
Irritation test	4	5	5	5

[Table 3]

	Example 9	Example 10	Comparative Example 1	Comparative Example 2	Comparative Example 3
Pile length	22mm	22mm	-	-	-
Pile shape	Cut	Cut	-	-	-
Ground varr dtex(dexitex)x f(filament	75× 24	←	-	-	-
Configuration	Double- sided pile cloth (2 sheet sewn)	Double- sided pile cloth (2 sheet sewn)	Double- sided pile cloth pile cloth	-	-
Dirt-wiping effeciency test A	5	5	3	3	2
Dirt-wiping effeciency test R	5	5	2	2	3
Irritation test	5	4	2	1	1

[Table 4]

			Example 1	Example 2	Example 3	Example 4
Sample description	Pile length		2.2mm	2.2mm	2.2mm	2.2mm
	Pile shape		Loop	Cut	Loop	Cut
	Ground varn dtex(dexitex)x f(filament)		75× 24	←	110× 24	←
	Configuration		Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth
Questionnaire description
When used as face wash paff	cosmetic removal	very favorble	33	42	33	40
When used as face wash paff		Not different from when only facial wash was used	15	6	14	7
		(Apparent) back staining of the dirt on cloth	2	2	3	3
	Texture	Very comfortable	32	43	32	42
		Comfortable	5	3	8	5
		Not comfortable	7	2	3	3
		Unpleasant	2	0	2	0
		Others	4	1	5	0
	Skin irritation	None	32	40	33	42
		some	8	2	7	3
		Significant	2	0	3	3
		Others	8	8	7	2
	Convenience in use	Very good	20	25	27	30
		Good	10	13	12	12
		Fair	18	9	9	6
		Bad	2	3	2	2
		Very Bad	0	0	0	0
		Others	0	0	0	0
	Possibility of future use	Yes	33	32	32	42
		Yes/ no	10	10	10	7
		No	5	3	3	0
		Others	2	5	5	1

[Table 5]

			Example 5	Example 6	Example 7	Example 8
Sample description	pile length		1.5mm	4.5mm	2.5mm	3.5mm
	Pile shape		Cut	Cut	Cut	Cut
	Ground varn dtex(dexitex)x f(filament)		110× 24	←	110× 24	←
	Configuration		Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth
Questionnaire description
When used as face wash paff	cosmetic removal	very favorble	43	42	45	44
When used as face wash paff		Not different from when only facial wash was used	7	2	3	3
		(Apparent) back staining of the dirt on cloth	0	6	2	3
	Texture	Very comfortable	42	48	48	48
		Comfortable	5	0	0	0
		Not comfortable	2	0	0	0
		Unpleasant	1	2	2	2
		Others	0	7	0	0
	Skin irritation	None	32	48	42	47
		Some	7	0	3	0
		Significant	3	0	0	0
		Others	8	2	5	3
	Convenience in use	Very good	27	42	38	35
		Good	8	3	5	3
		Fair	13	2	2	2
		Bad	0	0	2	2
		Very Bad	0	0	0	0
		Others	2	3	3	8
	Possibility of future use	Yes	35	43	42	45
		Yes/ no	10	5	5	3
		No	3	2	2	0
		Others	2	0	1	2

[Table 6]

			Example 9	Example 10	Comparative Example 1	Comparative Example 2	Comparative Example 3
Sample description	pile length		2.2mm	2.2mm	-	-	-
	pile shape		Cut	Cut	-	-	-
	Ground varn dtex(dexitex)x f(filament)		75× 24	←	-	-	-
	Configuration		Double-sided pile cloth (2 sheet sewn)	Double-sided pile cloth (2 sheet sewn)	Double- sided pile cloth	-	-
Questionnaire description
When used as face wash paff	cosmetic removal	very favorble	43	47	23	23	22
When used as face wash paff		Not different from when only facial wash was used	5	2	15	17	17
		(Apparent) back staining of the dirt on cloth	2	1	12	10	11
	Texture	Very comfortable	44	43	20	12	8
		Comfortable	3	2	8	10	10
		Not comfortable	0	0	10	18	22
		Unpleasant	0	0	10	8	8
		Others	3	5	2	2	2
	Skin irritation	None	40	42	17	5	5
		Some	3	2	13	15	8
		Significant	0	0	18	26	33
		Others	7	6	2	4	4
	Convenience in use	Very good	47	45	30	15	20
		Good	2	2	7	10	5
		Fair	0	0	3	23	23
		Bad	0	0	3	2	2
		Very Bad	0	0	2	0	0
		Others	1	3	5	0	0
	Possibility of future use	Yes	45	45	22	10	5
		Yes/ no	3	2	8	17	22
		No	0		15	20	20
		Others	2	3	5	3	3

[Table 7]

			Example 1	Example 2	Example 3	Example 4
Sample description	Pile length		2.2mm	2.2mm	2.2mm	2.2mm
	Pile shape		Loop	Cut	Loop	Cut
	Ground yarn dtex(dexitex)x f(filament)		75× 24	←	110× 24	←
	Configuration		Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth	Single- sided pile cloth
Questionnaire description
When used as face wash puff	Dirt removal	Very favorable	34	43	33	43
When used as face wash puff		Not different from when only facial wash was used	13	7	14	7
		(Apparent) back staining of the dirt on cloth	3	0	3	0
	Texture	Very comfortable	32	47	33	45
		Comfortable	5	0	8	2
		Not comfortable	7	2	5	0
		Unpleasant	2	1	2	2
		Others	4	0	2	1
	Skin irritation	None	35	40	37	43
		Some	5	2	5	2
		Significant	2	0	3	0
		Others	8	8	5	5
	Convenience in use	Very good	20	20	30	32
		Good	10	8	10	15
		Fair	15	13	5	2
		Bad	3	3	2	0
		Very Bad	2	6	2	1
		Others	0	0	1	0
	Possibility of future use	Yes	33	38	37	42
		Yes/ no	10	7	8	5
		No	5	3	3	2
		Others	2	2	2	1

[Table 8]

			Example 5	Example 6	Example 7	Example 8
Sample description	Pile length		1.5mm	4.5mm	2.5mm	3.5mm
	Pile shape		Cut	Cut	Cut	Cut
	Ground yarn dtex(dexitex)x f(filament)		110× 24	←	110× 24	←
	Configuration		Single- sided pile cloth	Singe- sided pile cloth	Single- sided pile cloth	Singe- sided pile cloth
Questionnaire description
When used as face wash puff	Dirt removal	Very favorable	45	45	47	45
When used as face wash puff		Not different from when only facial wash was used	5	5	2	3
		(Apparent) back staining of the dirt on cloth	0	0	1	2
	Texture	Very comfortable	43	48	48	48
		Comfortable	3	0	0	0
		Not comfortable	2	0	0	0
		Unpleasant	2	2	2	2
		Others	0	0	0	0
	Skin irritation	None	32	48	42	47
		Some	7	0	3	0
		Significant	3	0	0	0
		Others	8	9	5	3
	Convenience in use	Very good	33	42	38	35
		Good	10	3	5	3
		Fair	5	2	2	2
		Bad	0	0	2	2
		Very Bad	0	0	0	0
		Others	2	3	3	8
	Possibility of future use	Yes	35	43	42	45
		Yes/ no	10	5	5	3
		No	3	2	2	0
		Others	2	0	1	2

[Table 9]

			Example 9	Example 10	Comparative Example 1	Comparative Example 2	Comparative Example 3
Sample description	Pile length		2.2mm	2.2mm	-	-	-
	Pile shape		Cut	Cut	-	-	-
	Ground yarn dtex(dexitex)x f(filament)		75× 24	←	-	-	-
	Configuration		Double-sided pile cloth (2 sheet sewn)	Double-sided pile cloth (2 sheet sewn)	Double- sided pile cloth	-	-
Questionnaire description
When used as face wash puff	Dirt removal	Very favorable	43	45	23	18	15
When used as face wash puff		Not different from when only facial wash was used	5	3	17	19	20
		(Apparent) back staining of the dirt on cloth	2	2	10	13	15
	Texture	Very comfortable	44	42	17	13	8
		Comfortable	3	7	8	13	12
		Not comfortable	3	0	13	17	22
		Unpleasant	0	0	10	3	3
		Others	0	1	2	4	5
	Skin irritation	None	42	38	17	10	15
		Some	5	7	15	13	8
		Significant	0	0	15	24	17
		Others	3	5	3	3	10
	Convenience in use	Very good	42	40	22	18	15
		Good	7	7	5	5	5
		Fair	0	2	10	15	23
		Bad	0	0	7	5	2
		Very Bad	0	0	3	5	3
		Others	1	1	3	2	2
	Possibility of future use	Yes	45	43	18	11	12
		Yes/no	2	3	17	15	17
		No	0	2	15	23	20
		Others	3	2	0	1	1

Industrial Applicability

The skin care goods according to the present invention, which is significantly less simulative to the skin and superior in the efficiency of wiping off the dirt in the depth of the pores, is extremely useful in the field of skin care goods.

Claims

A skin care goods of a pile fabric, the pile fabric comprising pile yarns of nanofibers of thermoplastic polymer having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex and ground yarns.
The skin care goods according to Claim 1, wherein said thermoplastic polymer is nylon.
The skin care goods according to Claim 1, wherein the number-average monofilament fineness of said nanofibers is 4×10^-4 dtex or less.
The skin care goods according to Claim 1, wherein said pile yarn is a bundle of nanofiber filaments.
The skin care goods according to Claim 1, wherein the monofilament fineness of said ground yarns is larger than 8×10^-4 dtex.
The skin care goods according to Claim 1, wherein the monofilament fineness of said ground yarns is larger than 1×10^-1 dtex.
The skin care goods according to Claim 1, wherein the length of the pile is in the range of 1 to 10 mm.
The skin care goods according to Claim 1, wherein the length of the pile is in the range of 2 to 5 mm.
The skin care goods according to Claim 1, wherein the tips of the pile filaments are cut.
The skin care goods according to Claim 1, wherein said skin care goods has a sheet shape and double faced poile.
The skin care goods according to Claim 10, wherein said pile fabrics with the single faced pile are laminated to each other.
A method of producing the skin care goods according to Claim 1, comprising a step of forming a nanofiber having a number-average monofilament fineness of 1×10^-8 to 2.2×10^-3 dtex by treating a pile fabric having pile yarns of polymer alloy fibers consisting of sea and island components with a liquid dissolving the sea component but not dissolving the ground yarn.