JP2007077563A - Powder comprising ultrafine fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder comprising fiber dispersing elements and having excellent dispersibility and preservation stability when dispersed in a solvent. <P>SOLUTION: The powder comprising ultrafine fiber is constituted of the ultrafine fiber having 1-500 nm number average diameter and 1-1,000 μm number average particle diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a powder obtained by forming ultrafine fibers into a spherical shape and a method for producing the same.

  Conventionally, it has been promoted to form fibers into powder and use them as fillers for resins, paints, cosmetics and the like. As what shape | molded the fiber into powder, the fine powder which cut | disconnected the ultrafine fiber whose diameter is 3 micrometers or less to the length of 5-100 micrometers is mentioned, for example (refer patent document 1). However, this fine fiber powder is merely a powder in which fibers are dispersed, and it is obtained by mechanically crushing ultrafine fibers after freezing. At this time, the fibers are randomly crushed or cut in the radial direction or the longitudinal direction, and when viewed as powder, there is a large variation in the fiber length. Therefore, when added as a filler for resins, paints, cosmetics, etc., the fibers aggregate and settle down, resulting in poor dispersibility, storage stability is reduced, and evenly applied when these are applied There was a problem that I couldn't.

Therefore, there has been a demand for powders made of ultrafine fibers that are excellent in dispersibility and storage stability and are useful as various fillers.
JP 2001-146630 A

  An object of the present invention is to provide a powder composed of ultrafine fibers excellent in dispersibility and storage stability.

  In order to solve the above-mentioned problems, the powder of the present invention has a number average particle diameter of 1 to 1000 μm, which is composed of entangled super fine fibers having a number average diameter of 1 to 500 nm.

  According to the present invention, a powder having a granular structure in which the fiber diameter of the constituent fibers is small and the apparent density is small can be obtained. Therefore, the powder can be widely used not only as a filler for resins, paints and cosmetics, but also in various fields such as adsorbents, water retention agents, medical care and hygiene, taking advantage of such properties.

  Hereinafter, the powder of the present invention will be described in detail together with preferred embodiments.

  In the present invention, the powder means a powder having a granular structure in a dry state as in the case of general inorganic particles. The shape is a shape close to a perfect sphere, such as a flat shape or a rod shape, and the shape is not limited.

  The ultrafine fiber in the present invention refers to a form in which single fibers are dispersed, and specifically, a state in which the single fibers are not substantially aggregated can be exemplified. The term “substantially” includes those in which the single fibers are completely disjointed and non-oriented, and those in which a part of the single fibers are partly bonded and have a form such as a disjointed and non-oriented state. Any fibrous form at the fiber level may be used. That is, it is different from the oriented aggregate as described in JP-A No. 2004-162244. In addition, the fiber length, cross-sectional shape, etc. of a super extra fine fiber are not limited.

  The powder composed of the ultrafine fibers of the present invention is a granular product in which the dispersed ultrafine fibers are aggregated without being oriented or entangled with each other. Here, “aggregated without orientation” means that the single fibers in the powder exist in a disjointed state, and the intersections of the single fibers are bonded by intermolecular force or hydrogen bonding force. It is a state. In addition, “entangled with each other” means a state in which the intersections of the single fibers are joined by the entanglement between the single fibers. In addition, as an example of the powder which consists of a super fine fiber, the scanning electron microscope (SEM) photograph of the powder obtained in Example 1 mentioned later was shown to FIGS.

  It is important that the fibers constituting the ultrafine fiber of the present invention have a number average diameter of 1 to 500 nm. By making the number average diameter of the fibers within such a range, it becomes easy to disperse the ultrafine fibers in the dispersion medium in the manufacturing process, so that the fibers are likely to exist uniformly without being unevenly distributed in the powder. Moreover, there is an advantage that it is easy to obtain a powder having a small apparent density and a high porosity. The number average diameter of the fibers is preferably 1 to 200 nm, and more preferably 1 to 100 nm.

In the present invention, the number average diameter of the fibers can be determined as follows. That is, the powder was observed with a scanning electron microscope (SEM) at a magnification at which at least 150 single fibers could be observed in one field of view, and 150 single fibers randomly extracted in one field of the photograph taken. The fiber width in the direction perpendicular to the fiber longitudinal direction is taken as the fiber diameter, and the number average is calculated.
The number average particle size of the powder of the present invention is 1-1000 μm. By making such a particle size range, it can be blended with good dispersibility when blended into resins, paints, and cosmetics, and when these are applied, the powders do not aggregate and become lumpy and uniform. It becomes possible to apply. The number average particle diameter is more preferably 1 to 200 μm, and further preferably 1 to 100 μm or less.

  In the present invention, the number average particle diameter of the powder can be determined as follows. That is, the particle size of the powder was calculated in terms of a sphere by using commercially available image processing software from the photograph obtained by the SEM observation, and a simple average value thereof was obtained. At this time, the particle diameters of 150 powders randomly extracted within the same visual field are analyzed, and the number average is calculated.

  As the fibers constituting the ultrafine fibers used in the present invention, cellulose, cotton, natural fibers such as hemp, wool, and silk produced from wood pulp, regenerated fibers such as rayon, semi-synthetic fibers such as acetate, nylon Synthetic fibers such as polyester, acrylic and the like are mentioned, and the type of fiber is not particularly limited, but the fiber dispersion is preferably made of a thermoplastic polymer. Thereby, since a fiber dispersion can be manufactured using a melt spinning method, productivity can be made very high. The thermoplastic polymer as used in the present invention refers to polyethylene terephthalate (hereinafter sometimes referred to as PET), polytrimethylene terephthalate (hereinafter sometimes referred to as PTT), and polybutylene phthalate (hereinafter referred to as PBT). Polyester) such as polylactic acid (hereinafter sometimes referred to as PLA), nylon 6 (hereinafter sometimes referred to as N6), polyamide such as nylon 66, polystyrene (hereinafter also referred to as PS). , Polyolefins such as polypropylene (hereinafter may be referred to as PP), polyphenylene sulfide (hereinafter also referred to as PPS), and the like. Polycondensation polymers represented by polyesters and polyamides have a high melting point. Is more preferable. It is preferable that the melting point of the polymer is 165 ° C. or higher because the heat resistance of the fiber dispersion is good. For example, the melting point is 170 ° C for PLA, 255 ° C for PET, and 220 ° C for N6. The polymer may contain additives such as particles, a flame retardant, and an antistatic agent. Further, other components may be copolymerized as long as the properties of the polymer are not impaired. Furthermore, a polymer having a melting point of 300 ° C. or less is preferable because of ease of melt spinning.

  In the present invention, the production method of the ultrafine fiber is not particularly limited, and can be obtained by a conventional melt spinning method or the like. In particular, the nanoscale ultrafine fiber (hereinafter referred to as a number average diameter of 1 μm (1000 nm) or less) The following method can be given as an example of a production method for obtaining a nanofiber).

  That is, two or more types of polymers having different solubility in a solvent are made into a polymer alloy melt, which is spun and then cooled and solidified to form a fiber. Then, stretching and heat treatment are performed as necessary to obtain polymer alloy fibers. And the nanofiber used by this invention can be obtained by removing an easily soluble polymer with a solvent.

  Here, in the polymer alloy fiber which is a precursor of the nanofiber, the easily soluble polymer is the sea (matrix) and the hardly soluble polymer is the island (domain), and it is important to control the island size. Here, the island size is a value obtained by observing the cross section of the polymer alloy fiber with a transmission electron microscope (TEM) and evaluating it in terms of diameter. Since the diameter of the nanofiber is substantially determined by the island size in the precursor, the island size distribution is designed according to the diameter distribution of the nanofiber. For this reason, kneading of the polymer to be alloyed is very important, and it is preferable to perform high kneading with a kneading extruder, a stationary kneader or the like. Note that simple chip blends (for example, JP-A-6-272114, JP-A-10-53967, etc.) are insufficient to knead, so it is difficult to disperse islands with a size of several tens of nm.

  Specifically, as a guide when kneading, depending on the polymer to be combined, when using a kneading extruder, it is preferable to use a biaxial extrusion kneader, and when using a static kneader, the number of divisions is It is preferable to set it to 1 million or more. Moreover, in order to avoid blend spots and fluctuations in the blend ratio over time, it is preferable to measure each polymer independently and supply the polymers to the kneading apparatus independently. At this time, the polymer may be supplied separately as pellets, or may be supplied separately in a molten state. Further, two or more kinds of polymers may be supplied to the root of the extrusion kneader, or may be a side feed that supplies one component from the middle of the extrusion kneader.

  When a twin screw extrusion kneader is used as the kneading apparatus, it is preferable to achieve both high kneading and suppression of the polymer residence time. The screw is composed of a feeding part and a kneading part, but it is preferable that the kneading part has a length of 20% or more of the effective length of the screw so that high kneading can be achieved. In addition, the length of the kneading part is 40% or less of the effective screw length, so that excessive shear stress can be avoided and the residence time can be shortened. Can be suppressed. Further, the kneading part is positioned as close as possible to the discharge side of the twin-screw extruder, so that the residence time after kneading can be shortened and re-aggregation of the island polymer can be suppressed. In addition, when strengthening kneading, it is possible to provide a screw having a backflow function for sending the polymer in the reverse direction in an extrusion kneader.

  In addition, a combination of polymers is also important for ultra-fine dispersion of islands with a size of several tens of nanometers.

In order to make the island domain (cross section of the nanofiber) close to a circular shape, the island polymer and the sea polymer are preferably incompatible. However, it is difficult for the island polymer to be sufficiently finely dispersed by a simple combination of incompatible polymers. For this reason, it is preferable to optimize the compatibility of the polymer to be combined, but one index for this purpose is the solubility parameter (SP value). The SP value is a parameter reflecting the cohesive strength of a substance defined by (evaporation energy / molar volume) ^1/2 , and a polymer alloy having good compatibility may be obtained between materials having close SP values. The SP value is known for various polymers, and is described, for example, in “Plastic Data Book”, edited by Asahi Kasei Amidus Corporation / Plastics Editorial Department, page 189. It is preferable that the difference between the SP values of the two polymers is 1 to 9 (MJ / m ³ ) ^{1/2 because} it is easy to achieve both circularization of island domains and ultrafine dispersion due to incompatibility. For example, nylon 6 (N6) and PET have a SP value difference of about 6 (MJ / m ³ ) ^1/2, which is a preferable example. N6 and polyethylene (PE) have a SP value difference of 11 (MJ / m ³ ) About ^1/2, which is an undesirable example.

  Further, it is preferable that the difference in melting point between polymers is 20 ° C. or less because kneading with an extrusion kneader makes it difficult to produce a difference in the melting state in the extrusion kneader, so that high-efficiency kneading is easy.

  In addition, when a polymer which is easily decomposed or thermally deteriorated is used as one component, it is necessary to keep the kneading and spinning temperature low, which is also advantageous. Here, in the case of an amorphous polymer, since there is no melting point, it is replaced by the glass transition temperature, Vicat softening temperature or heat distortion temperature.

Furthermore, the melt viscosity is also important, and the melt viscosity of the sea polymer may greatly affect the spinnability, and it is preferable to use a low-viscosity polymer of 100 Pa · s or less as the sea polymer because the island polymer is easily dispersed. This can also significantly improve the spinnability. At this time, the melt viscosity is a value at a shear rate of 1216 sec ⁻¹ at the die surface temperature during spinning.

When spinning the ultrafinely dispersed polymer alloy used in the present invention, the spinneret design is important, but the cooling condition of the yarn is also important. As described above, since the polymer alloy is a very unstable molten fluid, it is preferable to quickly cool and solidify after discharging from the die. For this reason, it is preferable that the distance from a nozzle | cap | die to the cooling start shall be 1-15 cm. Here, the start of cooling means a position where positive cooling of the yarn is started, but in the actual melt spinning apparatus, it is replaced with this at the upper end of the chimney.
The nanofiber used in the present invention can be obtained by removing the easily soluble polymer of the polymer alloy fiber (sea-island type fiber) spun in this way with a solvent.

  Further, in the above-described method for producing nanofibers, in particular, when a stationary kneader is positioned directly above the die, a nanofiber having a long fiber shape in which the nanofibers are extended infinitely may be obtained.

  The nanofibers obtained by polymer alloy are completely different from the nanofibers obtained by conventional electrospinning, and the nanofibers are also drawn and heat-treated by drawing and heat-treating the polymer alloy fiber as a precursor. . Therefore, the tensile strength and shrinkage rate of the obtained nanofiber can be freely controlled. In addition, since the crystal orientation is achieved by stretching and heat treatment, a high-strength nanofiber having a degree of crystallinity of 20% or more and a strength equivalent to that of ordinary clothing fibers can be obtained. Therefore, it is easy to apply the fiber obtained by such a method to a method for producing a powder composed of ultrafine fibers as described below, and it is easy to obtain an appropriate structure strength as a powder. Can be easily formed. Further, the polymer alloy fiber as a precursor can be crimped.

Moreover, it is preferable that the ultrafine fiber used by this invention is 3 weight% or less of the fiber composition ratio of the single fiber whose single fiber diameter is larger than 500 nm. Here, the fiber component ratio of the coarse fiber means the ratio of the weight of the coarse single fiber (having a diameter of more than 500 nm) to the weight of the whole fiber having a diameter of more than 1 nm, and is calculated as follows. That is, a single fiber diameter of each fiber bundle and _{d i,} the square of the sum ^{_{(d 1 2 + d 2 2}} + ·· + d n 2) = Σd i for calculating ² (i = 1~n). Also, let D _{i be} the fiber diameter of each fiber bundle having a diameter greater than 500 nm, and calculate the sum of the squares (D ₁ ² + D ₂ ² +... + Dm ² ) = ΣD _i ² (i = 1 to m). By calculating the ratio of .SIGMA.D _i ² with respect to [Sigma] d _i ^2, the area ratio of the coarse fibers to total fibers, that is, to determine the weight ratio.

The ultrafine fibers used in the present invention have a fiber composition ratio of single fibers having a diameter of more than 500 nm, more preferably 1% by weight or less, and still more preferably 0.1% by weight or less. That is, this means that the presence of coarse fibers exceeding 500 nm is close to zero.
In addition, when the number average diameter of the ultrafine fibers is 200 nm or less, the fiber composition ratio of single fibers having a diameter of more than 200 nm is preferably 3% by weight or less, more preferably 1% by weight or less, and still more preferably 0.1%. It is to be not more than wt%. In addition, when the number average diameter of the single ultrafine fibers is 100 nm or less, the fiber composition ratio of the single fibers having a diameter greater than 100 nm is preferably 3% by weight or less, more preferably 1% by weight or less, and still more preferably. It is 0.1 weight% or less. Thus, by suppressing the composition ratio of coarse fibers in the fiber dispersion low, the resulting powder becomes homogeneous, and there are no individual differences when producing a plurality of powders from the same fiber dispersion, Good product quality stability can also be achieved. In the present invention, the ultrafine fibers may be dispersed in any state. Hereinafter, a state in which the ultrafine fibers are dispersed at a single fiber level in a dispersion medium is referred to as a fiber dispersion. . As will be described later, since the powder of the present invention is preferably produced from a fiber dispersion, a method for preparing an ultrafine fiber (nanofiber) dispersion will be described next.

  The fibers (nanofibers) obtained as described above are cut into a desired fiber length using a guillotine cutter, a cutting machine such as a slicing machine and a cryostat. Since the nanofiber obtained by the melt spinning method as described above is obtained as a fiber bundle in which the fibers are aligned in a certain direction, it is possible to align all cut fibers to a desired fiber length. In addition, with nanofiber fibers by electrospinning method, fiber bundles with fibers aligned in a certain direction cannot be produced from the production method, so the fiber length cannot be made even by cutting, and a fiber dispersion is produced. It was unsuitable to do.

  In order to improve the fiber dispersibility in the fiber dispersion, if the fiber length of the cut fiber is too long, the dispersibility tends to be poor. On the other hand, if the fiber length of the cut fiber is too short, the degree of fiber entanglement becomes small when it is made into powder, and as a result, it becomes difficult for the powder to take a granular structure or the strength of the powder structure is lowered. From the viewpoint of improving these, the fiber length is preferably cut to 0.2 to 30 mm. The fiber length is more preferably 0.5 to 10 mm, and still more preferably 0.8 to 5 mm.

  Next, the obtained cut fiber is dispersed in a dispersion medium. As a dispersion medium, considering not only water but also affinity with fibers, hydrocarbon solvents such as hexane and toluene, halogenated hydrocarbon solvents such as chloroform and trichloroethylene, ethanol, isopropyl alcohol, butyl alcohol and hexanol Alcohol solvents, ether solvents such as ethyl ether, tetrahydrofuran and dioxane, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as methyl acetate and ethyl acetate, polyhydric alcohol solvents such as ethylene glycol and propylene glycol, Common organic solvents such as amines such as triethylamine and N, N-dimethylformamide and amide solvents can be suitably used. However, in consideration of safety and environment, it is preferable to use water as a dispersion medium. In addition, a dispersion medium may be individual or may combine 2 or more types.

  Further, from the viewpoint of producing powder by removing the dispersion medium as described below, it is preferable that the dispersion medium has such a property that it can be sublimated at normal pressure or low pressure. It is preferable to use water having water.

  As a method for dispersing the cut fiber in the dispersion medium, a stirrer such as a mixer, a homogenizer or an ultrasonic stirrer can be used. When nanofibers obtained by melt spinning are in the form of agglomeration of single fibers in cut fibers, it is preferable to beat in a dispersion medium as a pretreatment step for dispersion by stirring, and Niagara Beater, refiner, cutter, laboratory grinder, biomixer, household mixer, roll mill, mortar, PFI beating machine, bath type ultrasonic processor, probe type ultrasonic processor, etc. It can be dispersed up to the book and administered in a dispersion medium.

  In order to prepare a dispersion of nanofibers, the fibers themselves must have mechanical strength that can withstand various operations. Therefore, they are prepared by melt spinning as described above and oriented and crystallized. It is preferable to use nanofibers that have obtained mechanical strength. The nanofibers produced by the above production method have a crystallinity of 20% or more, and have the same strength as ordinary clothing fibers.

  Moreover, in order to make the dispersibility of the ultrafine fibers in the fiber dispersion uniform, the concentration of the ultrafine fibers in the dispersion is preferably 0.001 to 30% by weight with respect to the total weight of the dispersion. In particular, since the granular structure in the powder greatly depends on the presence state of the fibers in the dispersion, that is, the distance between the fibers, it is preferable to control the concentration of the ultrafine fibers in the dispersion within the above range. The concentration of ultrafine fibers in the dispersion is more preferably 0.01 to 10% by weight, still more preferably 0.05 to 5% by weight.

  In addition, an additive such as a dispersant may be used in the dispersion as necessary in order to suppress re-aggregation of the ultrafine fibers or to improve the adhesion or adhesion between the fibers. Examples of the additive include natural polymers, synthetic polymers, organic compounds, and inorganic compounds. For example, as a polymer-based additive for use in an aqueous system, an anionic compound such as a polycarboxylic acid salt or a cation such as a quaternary ammonium salt is used as an additive that suppresses aggregation between fibers and increases dispersibility. It can be selected from nonionic compounds such as polyoxyethylene compounds, polyoxyethylene ethers and polyoxyethylene esters. The molecular weight of the additive for improving the dispersibility is preferably 1000 to 50000, and more preferably 5000 to 15000.

  Further, the concentration of the additive is preferably 0.00001 to 20% by weight, more preferably 0.0001 to 5% by weight, and most preferably 0.01 to 1% by weight, based on the entire dispersion. Thus, a sufficient dispersion effect can be obtained.

  Next, a method for producing a powder from the fiber dispersion will be described.

  In order to granulate the fibers (nanofibers) in the dispersion obtained above to obtain the powder of the present invention, it is necessary to dry the fiber dispersion and remove the dispersion medium. Examples of the drying method for drying the fiber dispersion and removing the dispersion medium include natural drying, hot air drying, vacuum drying, freeze drying, and the like. For example, it is possible to freeze the fiber dispersion, shape it into a spherical shape by pulverization or various techniques, and further freeze-dry it to obtain the powder of the present invention. For this purpose, it is preferable to obtain the powder of the present invention by spray drying. In spray drying, a spray drying apparatus is used to remove the dispersion medium with hot air while spraying the dispersion liquid as fine droplets and collect the powder. As a result, a powder in which the fibers are gathered together in a nearly spherical shape can be obtained. As a method of spraying as droplets, various methods such as a method of spraying with a nozzle and a method of flying droplets with a rotating disk can be employed.

  The number average particle diameter of the powder of the present invention is 1-1000 μm, but when powdered by spray drying, the diameter of the droplet, the concentration of the ultrafine fiber in the fiber dispersion, the fiber diameter of the ultrafine fiber, etc. By adjusting, the number average particle diameter of the powder particles can be controlled to 1 to 1000 μm. That is, since the powder particle size does not become larger than the droplet diameter, the number average particle size of the powder is controlled mainly by adjusting the droplet diameter and the ultrafine fiber concentration of the fiber dispersion. Can do. The diameter of the droplets can be adjusted by the nozzle structure and spraying speed in the case of spraying with a nozzle, and by the dropping speed of the dispersion and the rotational speed of the disk in the case of spraying droplets with a rotating disk. it can.

  In addition, the nanofibers used in the present invention can be subjected to various treatments depending on the intended use. The treatment includes heat treatment, cooling treatment, freezing treatment, hydrolysis treatment with acid or alkali, solvent treatment, hydrothermal treatment, glow discharge treatment, plasma discharge treatment, corona discharge treatment, γ ray treatment, electron beam treatment, laser treatment. , UV treatment, infrared treatment, ozone treatment, pressure treatment, decompression treatment, pressurized steam treatment, gas treatment, steam treatment, flame treatment, coating treatment, graft polymerization treatment, stretching treatment, vacuum treatment, crosslinking treatment, chemical modification Examples include, but are not limited to, processing and ion implantation.

  As a treatment method, in a state where the nanofibers formed with the powder are intertwined, the nanofiber surface is softened, melted or dissolved, and then re-solidified, thereby bonding the nanofibers by partially fusing them. Is also possible. Typical examples of such treatment include heat treatment, electron beam treatment and solvent treatment, and among them, pressurized steam treatment is most preferably used. In this case, it is preferable to perform the treatment under a temperature condition not lower than the glass transition temperature and not higher than the melting temperature of the synthetic polymer used as the raw material of the nanofiber.

  Further, these treatments may be performed at any point in time before or after the powder is produced.

  Particularly in these treatments, the nanofibers can be partially bonded to each other to improve the durability against external physical forces such as water resistance and pressure resistance while maintaining the nano-level structure. It becomes possible. Preferred treatment methods for bonding such nanofibers include coating by coating treatment, fusion by heat treatment, and welding by solvent treatment as preferred embodiments. However, the coating treatment can improve durability by adhering the nanofibers by coating the nanofibers with other polymers, but it may significantly change the physical properties of the nanofibers themselves. In addition, welding by solvent treatment is highly likely to change the nano-level structure of the nanofiber. Therefore, heat treatment is more preferably used particularly in that the physical properties and nanostructure of the nanofiber itself are not changed.

The paint containing the powder of the present invention is composed of the powder of the present invention and a solvent, and the powder of the present invention is dispersed in the solvent. Further, various additives such as a viscosity agent for adjusting viscosity and a dispersant for improving dispersibility may be blended. There is no limitation in particular about the kind of solvent and various additives, What is necessary is just to select suitably according to the objective and a use. Examples of the solvent include the following organic solvents such as alcohols, esters, glycols, glycerins, ketones, ethers, amines, lower fatty acids such as lactic acid / butyric acid, pyridine, tetrahydrofuran, There are furfuryl alcohol, acetonitriles, methyl lactate, ethyl lactate, etc., which can be used alone or in combination of two or more.
A cosmetic containing the powder of the present invention refers to a liquid or solid product containing the powder of the present invention and various active ingredients and solvents.

As the solvent, water and / or oil and / or an organic solvent can be used in appropriate combination. Oils include linseed oil, corn oil, olive oil, sunflower oil, rapeseed oil, sesame oil, soybean oil, cacao oil, coconut oil, palm oil, owl, and other natural oils, paraffin, petrolatum, ceresin, liquid paraffin, squalane, wax, There are higher fatty acids, silicone oils, cross-linked silicone oils, etc., which can be used alone or in combination of two or more.
Moreover, as said organic solvent, said various solvent can be used, and it can be used even if individual or it combines 2 or more types.

  Furthermore, there are various amino acids, proteins, vitamins, etc. as active ingredients, specifically, ascorbic acid and vitamin E, which are the main components of hyaluronic acid, kojic acid, collagen, ceramide, squalane, lecithin, vitamin C. Examples of such ingredients as tocopherol, which are moisturizing and moisturizing the skin and keeping the skin fresh.

  As described above, the powder of the present invention is useful as a filler for paints and cosmetics, but the powder of the present invention is also useful as a filler for resins. Further, the powder of the present invention is useful for adsorbents, water retention agents and the like by making use of its surface area, and is also suitable for powder materials in various fields such as medical care and hygiene.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, the measuring method in an Example used the following method.

A. Polymer melt viscosity The polymer melt viscosity was measured with a Capillograph 1B manufactured by Toyo Seiki Seisakusho. The polymer storage time from sample introduction to measurement start was 10 minutes.

B. Melting | fusing point The peak top temperature which shows melting | dissolving of a polymer by 2nd run using DSC-7 made from Perkin Elmaer was made into melting | fusing point of a polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg.

C. Worcester spots of polymer alloy fibers (U%)
Measurement was performed in the normal mode at a yarn feeding speed of 200 m / min using a USTER TESTER 4 manufactured by Zerbegger Worcester.

D. SEM observation Platinum was vapor-deposited on the sample and observed with an ultra-high resolution electrolytic emission scanning electron microscope.
SEM device: UHR-FE-SEM manufactured by Hitachi, Ltd.
E. Cross-sectional observation of nanofibers by TEM Using ultrafine fiber bundles before dispersion, ultrathin sections were cut in the cross-sectional direction of the bundles, and cross-sections of nanofibers were observed by TEM. Moreover, metal dyeing | staining was given as needed.
TEM apparatus: H-7100FA type manufactured by Hitachi, Ltd. Number average diameter of fiber The number average diameter of the island component in the polymer alloy fiber and the number average diameter of the single fiber (nanofiber) of the fiber bundle are determined as follows. That is, in the TEM of the above E item, at least 300 island components in the case of polymer alloy fibers and at least 300 single fibers in the case of fiber bundles are observed at a magnification that can be observed in one field of view. A simple average value of the diameter of each island or single fiber was obtained from the photograph using image processing software (WINROOF). At this time, 300 island diameters were extracted for the island component and 300 diameters were extracted for the island component, which were randomly extracted within the same field of view, and used for the calculation.

On the other hand, the number average diameter of the single fibers constituting the powder is determined as follows.
That is, at least 150 or more single fibers are observed at a magnification that can be observed in one field of view with the SEM of the above section D, and are perpendicular to the longitudinal direction of the fibers using image processing software (WINROOF). The fiber width in the direction was taken as the fiber diameter, and a simple average value was obtained. At this time, the diameters of 150 fibers randomly extracted within the same visual field were analyzed and used for calculation.

G. Utilizing the diameter analysis of single fibers in the fiber component ratio the fiber bundles of single fibers in the fiber bundles, each single fiber diameter in the ultrafine fiber bundles and d _i, the square of the sum (d 1 ₂ ⁺ d ^{_{2 2 + ·· + d n 2}} ) = Σd i for calculating ² (i = 1~n). Further, each of the fiber diameter in diameter 500nm greater than the fiber bundle and _{D i,} calculate the square of the sum ^{_{(D 1 2 + D 2 2}} + ·· + Dm 2) = ΣD i 2 (i = 1~m) To do. By calculating the ratio of .SIGMA.D _i ² with respect to [Sigma] d _i ^2, the area ratio of the coarse fibers to total fibers, i.e. a fiber structure ratio.

H. Mechanical properties At room temperature (25 ° C.), an initial sample length = 200 mm, a tensile speed = 200 mm / min, and a load-elongation curve was obtained under the conditions shown in JIS L1013. Next, the load value at the time of breaking was divided by the initial fineness, which was taken as the strength, the elongation at break was divided by the initial sample length, and a strong elongation curve was obtained as the elongation.

I. The number average particle diameter of the powder The number average particle diameter of the powder is determined as follows.
That is, at least 150 powders are observed with a magnification that can be observed in one field of view with the SEM of the above section D, and the particle size of the powder is calculated in terms of spheres using image processing software (WINROOF) from the photograph by observation. A simple average value of was obtained. At this time, the particle sizes of 150 powders randomly extracted within the same field of view were analyzed and used for calculation.

<Production Example 1 of Dispersion>
Melt viscosity 57 Pa · s (240 ° C., shear rate 2432 sec ⁻¹ ), melting point 220 ° C. N6 (20 wt%) and weight average molecular weight 120,000, melt viscosity 30 Pa · s (240 ° C., shear rate 2432 sec ⁻¹ ), melting point 170 ° C. poly-L lactic acid (optical purity of 99.5% or higher) (80% by weight) was melt-kneaded at 220 ° C. with a biaxial extrusion kneader to obtain a polymer alloy chip. N6 had a melt viscosity of 53 Pa · s at 262 ° C. and a shear rate of 121.6 sec ⁻¹ . The melt viscosity of this poly L lactic acid at 215 ° C. and a shear rate of 1216 sec ⁻¹ was 86 Pa · s. The kneading conditions at this time were as follows.
Polymer supply: N6 and poly-L lactic acid were weighed separately and supplied separately to the kneader.
Screw type: Fully meshed in the same direction Double thread screw: Diameter 37mm, Effective length 1670mm
L / D: 45.1
The kneading part length is 1/3 of the effective screw length on the discharge side. Temperature: 220 ° C
Vent: 2 locations.

  This polymer alloy chip was melted at a melting portion of 230 ° C. and led to a spin block having a spinning temperature of 230 ° C. The polymer alloy melt was filtered with a metal nonwoven fabric having a limit filtration diameter of 15 μm, and then melt-spun from a die with a die surface temperature of 215 ° C. at a spinning speed of 3500 m / min. At this time, a base having a base hole diameter of 0.3 mm and a discharge hole length of 0.55 mm was used, but almost no ballast phenomenon was observed. And the discharge amount per single hole at this time was 0.94 g / min. Furthermore, the distance from the base lower surface to the cooling start point (the upper end of the chimney) was 9 cm. The discharged yarn is cooled and solidified with a cooling air of 20 ° C. over 1 m, and is supplied with an oil supply guide installed 1.8 m below the base, and then passed through an unheated first take-up roller and second take-up roller. Winded up. Thereafter, the yarn was subjected to a drawing heat treatment with a first hot roller having a temperature of 90 ° C. and a second hot roller having a temperature of 130 ° C. At this time, the draw ratio by the 1st hot roller and the 2nd hot roller was 1.5 times. The obtained polymer alloy fiber showed excellent properties of 62 dtex, 36 filament, strength 3.4 cN / dtex, elongation 38%, U% = 0.7%. Further, when a cross section of the obtained polymer alloy fiber was observed with a TEM, poly-L-lactic acid showed a sea and N6 showed an island-island structure, and the number average diameter of the island N6 was 55 nm, and N6 was very finely dispersed. A polymer alloy fiber, which is a precursor of the converted N6 nanofiber, was obtained.

  The polymer alloy fiber thus obtained is immersed in a 5% aqueous sodium hydroxide solution at 95 ° C. for 1 hour to hydrolyze and remove 99% or more of the poly-L lactic acid component in the polymer alloy fiber, neutralized with acetic acid, and washed with water. And dried to obtain a fiber bundle of N6 nanofibers. As a result of analyzing this fiber bundle from a TEM photograph, the number average diameter of the N6 nanofibers was 60 nm, which is an unprecedented fineness, and the fiber composition ratio of the single fiber diameter larger than 100 nm was 0% by weight.

  The obtained fiber bundle of N6 nanofibers was cut into a length of 2 mm to obtain cut fibers of N6 nanofibers. A tappy standard Niagara test beater (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was charged with 23 L of water and 30 g of the previously obtained cut fiber, preliminarily beaten for 5 minutes, and then the excess water was removed to collect the fiber. The weight of this fiber was 250 g, and its water content was 88% by weight. 250 g of water-containing fiber was charged as it was into an automatic PFI mill (manufactured by Kumagai Riki Kogyo Co., Ltd.) and beaten for 6 minutes at a rotation speed of 1500 rpm and a clearance of 0.2 mm. In an oster blender (manufactured by oster), 42 g of beaten fiber, 0.5 g of Charol (registered trademark) AN-103P (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000) as an anionic dispersant as a dispersant, and 500 g of water was charged, and the mixture was stirred for 30 minutes at a rotational speed of 13900 rpm, to obtain a dispersion 1 having a N6 nanofiber content of 1.0% by weight.

<Production Example 2 of Dispersion>
Similar to Dispersion Production Example 1 except that N6 in Dispersion Production Example 1 was N6 (45 wt%) having a melt viscosity of 212 Pa · s (262 ° C., shear rate 121.6 sec ⁻¹ ) and a melting point of 220 ° C. The polymer alloy chip was obtained by melt-kneading. Next, this was melt-spun and stretched and heat treated in the same manner as in Production Example 1 of the dispersion to obtain a polymer alloy fiber. The obtained polymer alloy fiber exhibited excellent properties of 67 dtex, 36 filaments, strength 3.6 cN / dtex, elongation 40%, U% = 0.7%. Moreover, when the cross section of the obtained polymer alloy fiber was observed with a TEM, as in dispersion production example 1, poly L lactic acid was the sea and N6 was the island-island structure, and the number average diameter of the island N6 was A polymer alloy fiber having a thickness of 110 nm and ultra-dispersed N6 was obtained.

  The obtained polymer alloy fibers were hydrolyzed and removed 99% or more of the poly-L lactic acid component in the polymer alloy fibers in the same manner as in Production Example 1 of the dispersion, neutralized with acetic acid, washed with water, dried, and N6 nanofibers Fiber bundles were obtained. As a result of analyzing this fiber bundle from a TEM photograph, the number average diameter of N6 nanofibers is 120 nm, which is an unprecedented thinness, and the fiber composition ratio of single fiber diameter larger than 500 nm is 0% by weight, and the single fiber diameter is 200 nm. The larger fiber composition ratio was 1% by weight.

  The obtained fiber bundle of N6 nanofibers was cut into a length of 2 mm to obtain cut fibers of N6 nanofibers. This was preliminarily beaten in the same manner as in Production Example 1 of the dispersion to obtain N6 nanofibers having a water content of 88% by weight, and further beaten in the same manner as in Production Example 1 of the dispersion. In an oster blender (manufactured by oster Co., Ltd.), 21 g of beaten fiber, Charol (registered trademark) AN-103P (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000), which is an anionic dispersant, and 500 g of water are charged The mixture was stirred at a rotational speed of 13900 rpm for 30 minutes to obtain a dispersion 2 having a N6 nanofiber content of 0.5% by weight.

<Production Example 3 of Dispersion>
The amount of water and dispersant added to the oster blender (manufactured by oster) was not changed, but the amount of N6 nanofibers was changed to 0.1% by weight by changing the amount of fibers after beating. A dispersion 3 was obtained in the same manner as in Production Example 2.

<Production Example 4 of Dispersion>
N6 nanofiber dispersion liquid 4 was obtained in the same manner as in Production Example 1 of the dispersion liquid, except that the water charged into the oster blender (manufactured by oster) and the amount of fibers after beating were not changed and the dispersant was not used.

<Production Examples 5 and 6 of dispersion>
N6 nanofibers were prepared in the same manner as in Production Example 1 of the dispersion, except that the cut length of N6 nanofibers was 0.5 mm in Dispersion Production Example 5 and the cut length of N6 nanofibers was 5 mm in Dispersion Production Example 6. Dispersions 5 and 6 having a content of 1.0 wt% were obtained.

<Production Example 7 of Dispersion>
Polystyrene (PS) copolymerized with 22% PBT (polybutylene terephthalate) having a melt viscosity of 120 Pa · s (262 ° C., 121.6 sec ⁻¹ ) and a melting point of 225 ° C. and 2 ethylhexyl acrylate was used, and the content of PBT was 20 wt. %, The kneading temperature was 240 ° C., and melt-kneaded in the same manner as in Production Example 1 of the dispersion to obtain a polymer alloy chip. At this time, the melt viscosity of copolymerized PS at 262 ° C. and 121.6 sec ⁻¹ was 140 Pa · s, and the melt viscosity at 245 ° C. and 1216 sec ⁻¹ was 60 Pa · s.

  This was melt-spun in the same manner as in Production Example 1 of the dispersion at a melting temperature of 260 ° C., a spinning temperature of 260 ° C. (die surface temperature of 245 ° C.), and a spinning speed of 1200 m / min. At this time, a die having a discharge hole diameter of 0.7 mm and a discharge hole length of 1.85 mm provided with a measuring portion having a diameter of 0.3 mm above the discharge hole was used. The spinnability was good and the yarn breakage was 1 in 1 t spinning. The discharge rate per single hole at this time was 1.0 g / min. The obtained undrawn yarn was drawn and heat treated in the same manner as in Production Example 1 of the dispersion at a drawing temperature of 100 ° C., a draw ratio of 2.49 times, and a heat setting temperature of 115 ° C. The obtained drawn yarn was 161 dtex, 36 filaments, and the strength was 1.4 cN / dtex, the elongation was 33%, and U% = 2.0%. When the cross section of the obtained polymer alloy fiber was observed by TEM, the copolymer PS showed the sea, the PBT showed the island-island structure, the number average diameter of the PBT was 70 nm, and the PBT was nano-sized and uniformly dispersed. A polymer alloy fiber was obtained.

  By immersing the obtained polymer alloy fiber in trichlene, 99% or more of the copolymer PS, which is a sea component, was eluted and dried to obtain a fiber bundle of PBT nanofibers. As a result of analyzing this fiber bundle from a TEM photograph, the number average diameter of the PBT nanofiber is 85 nm, which is an unprecedented fineness. The fiber composition ratio of the single fiber diameter larger than 200 nm is 0% by weight, and the single fiber diameter is 100 nm. The larger fiber ratio was 1% by weight.

  The obtained fiber bundle of PBT nanofiber was cut into a length of 2 mm to obtain a cut fiber of PBT nanofiber. This was preliminarily beaten in the same manner as in Production Example 1 of the dispersion to obtain PBT nanofibers having a water content of 80% by weight, and further beaten in the same manner as in Production Example 1 of the dispersion. 25 g of this beaten fiber, 0.5 g of Neugen (registered trademark) EA-87 (Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000), which is a nonionic dispersant as a dispersant, and 500 g of water, Oster Blender (Oster Corporation) And the mixture was stirred at a rotational speed of 13900 rpm for 30 minutes to obtain a dispersion 7 having a PBT nanofiber content of 1.0% by weight.

<Dispersion Production Example 8>
PTT (polytrimethylene terephthalate) having a melt viscosity of 220 Pa · s (262 ° C., 121.6 sec ⁻¹ ) and a melting point of 225 ° C. and copolymer PS (polystyrene) (“Estyrene” KS-18, manufactured by Nippon Steel Chemical Co., Ltd.) Methyl methacrylate copolymer, melt viscosity 110 Pa · s, 262 ° C., 121.6 sec ⁻¹ ), PTT content 25% by weight, kneading temperature 240 ° C. A polymer alloy chip was obtained. The copolymer PS had a melt viscosity of 76 Pa · s at 245 ° C. and 1216 sec ⁻¹ .

  This was melt-spun in the same manner as in Production Example 1 of the dispersion at a melting temperature of 260 ° C., a spinning temperature of 260 ° C. (die surface temperature of 245 ° C.), and a spinning speed of 1200 m / min. At this time, a spinneret having a diameter of 0.23 mm and a discharge hole diameter of 2 mm and a discharge hole length of 3 mm was used as the base. The spinnability was good and the yarn breakage was 1 in 1 t spinning. The single-hole discharge rate at this time was 1.0 g / min. The obtained undrawn yarn was stretched 2.6 times in a 90 ° C. hot water bath. The obtained polymer alloy fiber was 140 detex, 36 filaments, the strength was 1.3 cN / dtex, and the elongation was 25%. When the cross section of this was observed with a TEM, the copolymer PS showed sea and PTT showed an island-island structure. The number average diameter of PTT was 75 nm, and PTT was nano-sized and uniformly dispersed. Obtained. Further, this was a single fiber fineness of 3.9 dtex, a strength of 1.3 cN / dtex, and an elongation of 25%.

  99% or more of the PS component in the polymer alloy fiber was eluted from the obtained polymer alloy fiber in the same manner as in Production Example 7 of the dispersion and dried to obtain a fiber bundle of PTT nanofibers. As a result of analyzing this fiber bundle from a TEM photograph, the number average diameter of the PTT nanofibers is 95 nm, which is an unprecedented fineness. The fiber composition ratio of the single fiber diameter larger than 200 nm is 0% by weight, and the single fiber diameter is 100 nm. The larger fiber composition ratio was 3% by weight.

  The obtained PTT nanofiber bundle was cut to a length of 2 mm to obtain PTT nanofiber cut fibers. This was preliminarily beaten in the same manner as in Production Example 1 of the dispersion to obtain PTT nanofibers having a water content of 80% by weight, and further beaten in the same manner as in Production Example 1 of the dispersion. 25 g of this beaten fiber, 0.5 g of Neugen (registered trademark) EA-87 (Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000), which is a nonionic dispersant as a dispersant, and 500 g of water, Oster Blender (Oster) ) And stirred at a rotational speed of 13900 rpm for 30 minutes to obtain a dispersion 8 having a PTT nanofiber content of 1.0 wt%.

<Dispersion Production Example 9>
Similar to Dispersion Production Example 1 except that N6 in Dispersion Production Example 1 was changed to PP (polypropylene) (23 wt%) having a melt viscosity of 350 Pa · s (220 ° C., 121.6 sec ⁻¹ ) and a melting point of 162 ° C. And kneaded to obtain a polymer alloy chip. The melt viscosity of poly L lactic acid at 220 ° C. and 121.6 sec ⁻¹ was 107 Pa · s. This polymer alloy chip was melt-spun at the melting temperature of 230 ° C., the spinning temperature of 230 ° C. (the base surface temperature of 215 ° C.), the single-hole discharge rate of 1.5 g / min, and the spinning speed of 900 m / min. went. The obtained undrawn yarn was drawn and heat treated in the same manner as in Production Example 1 of the dispersion at a drawing temperature of 90 ° C., a draw ratio of 2.7 times, and a heat setting temperature of 130 ° C. The obtained polymer alloy fiber had 77 dtex, 36 filament, strength 2.5 cN / dtex, and elongation 50%.

  The polymer alloy fiber obtained is immersed in 98% 5% aqueous sodium hydroxide solution for 1 hour to hydrolyze and remove 99% or more of the poly-L lactic acid component in the polymer alloy fiber, neutralized with acetic acid, and washed with water. And dried to obtain a bundle of PP nanofibers. As a result of analyzing this fiber bundle from the TEM photograph, the number average diameter of PP nanofibers was 240 nm, and the fiber ratio of single fiber diameters larger than 500 nm was 0% by weight.

  The obtained PP nanofiber bundle was cut into 2 mm lengths to obtain PP nanofiber cut fibers. This was preliminarily beaten in the same manner as in Production Example 1 of the dispersion to obtain PP nanofibers having a water content of 75% by weight, and further beaten in the same manner as in Production Example 1 of the dispersion. 20 g of the beaten fiber, 0.5 g of Neugen (registered trademark) EA-87 (Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000), which is a nonionic dispersant as a dispersant, and 500 g of water, Oster Blender (Oster Corporation) And the mixture was stirred at a rotational speed of 13900 rpm for 30 minutes to obtain a dispersion 9 having a PP nanofiber content of 1.0% by weight.

<Dispersion Production Example 10>
Biaxially, under the following conditions, PET having a melt viscosity of 280 Pa · s (300 ° C., 1216 sec ⁻¹ ) is 80 wt% and polyphenylene sulfide (PPS) having a melt viscosity of 160 Pa · s (300 ° C., 1216 sec ⁻¹ ) is 20 wt%. Melt kneading was performed using an extrusion kneader to obtain a polymer alloy chip. Here, the PPS used was a linear type and the molecular chain terminal was replaced with calcium ions.
Screw L / D = 45
The kneading part length is 34% of the effective screw length
The kneading part was dispersed throughout the screw.
There are two backflow sections along the way.
Polymer supply PPS and PET were weighed separately and supplied separately to a kneader.
Temperature 300 ° C
No vent.

  The polymer alloy chip obtained here was introduced into a spinning machine in the same manner as in Production Example 1 of the dispersion to carry out spinning. At this time, the polymer alloy melt was filtered with a metal nonwoven fabric having a spinning temperature of 315 ° C. and a limit filtration diameter of 15 μm, and then melt-spun from a die having a die surface temperature of 292 ° C. At this time, as the base, a nozzle having a discharge hole diameter of 0.6 mm provided with a measuring portion having a diameter of 0.3 mm above the discharge hole was used. And the discharge amount per single hole at this time was 1.1 g / min. Furthermore, the distance from the base lower surface to the cooling start point was 7.5 cm. The discharged yarn is cooled and solidified over 1 m with a cooling air of 20 ° C., and after the process oil agent mainly composed of fatty acid ester is supplied, it is 1000 m / min through the non-heated first take-up roller and the second take-up roller. It was wound up. The spinnability at this time was good, and there was no yarn breakage during continuous spinning for 24 hours. This was subjected to a stretching heat treatment with the temperature of the first hot roller being 100 ° C. and the temperature of the second hot roller being 130 ° C. At this time, the draw ratio between the first hot roller and the second hot roller was 3.3 times. The obtained polymer alloy fiber showed excellent properties of 400 dtex, 240 filament, strength 4.4 cN / dtex, elongation 27%, U% = 1.3%. Moreover, when the cross section of the obtained polymer alloy fiber was observed by TEM, PPS was dispersed uniformly as an island with a diameter of less than 100 nm in PET, which was a sea polymer. Moreover, when the circle-equivalent diameter of the island was analyzed by the image analysis software WINROOF, the average diameter of the island was 65 nm, and polymer alloy fibers in which PPS was ultra-dispersed were obtained.

  The polymer alloy fibers obtained are immersed in 98% 5% aqueous sodium hydroxide solution for 2 hours to hydrolyze and remove 99% or more of the PET components in the polymer alloy fibers, neutralized with acetic acid, washed with water and dried. As a result, a fiber bundle of PPS nanofibers was obtained. As a result of analyzing this fiber bundle from the TEM photograph, the number average diameter of the PPS nanofibers was 60 nm, which is an unprecedented fineness, and the fiber ratio of the single fiber diameter larger than 100 nm was 0% by weight.

  The obtained PPS nanofiber bundle was cut into a length of 3 mm to obtain PPS nanofiber cut fibers. This was preliminarily beaten in the same manner as in Production Example 1 of the dispersion to obtain PPS nanofibers having a water content of 80% by weight, and further beaten in the same manner as in Production Example 1 of the dispersion. 25 g of this beaten fiber, 0.5 g of Neugen (registered trademark) EA-87 (Daiichi Kogyo Seiyaku Co., Ltd .: molecular weight 10,000), which is a nonionic dispersant as a dispersant, and 500 g of water, Oster Blender (Oster Corporation) And the mixture was stirred at a rotational speed of 13900 rpm for 30 minutes to obtain a dispersion 10 having a PPS nanofiber content of 1.0 wt%.

<Dispersion Production Example 11>
A seawater component of 60% by weight of an alkali-soluble copolymer polyester resin, an island component of 40% by weight of N6 resin, 100 islands by melt spinning, and a polymer array composite fiber of 5.3 dtex (hereinafter referred to as composite fiber) ) Was stretched 2.5 times to obtain a 2.1 dtex conjugate fiber. The composite fiber had a strength of 2.6 cN / dtex and an elongation of 35%. Thereafter, the composite fiber is treated with a 3% aqueous sodium hydroxide solution at 98 ° C. for 1 hour to hydrolyze and remove 99% or more of the polyester component in the composite fiber, neutralized with acetic acid, washed with water, It dried and the ultrafine fiber of N6 was obtained. When the average single yarn fineness of the obtained ultrafine fiber was analyzed from the TEM photograph, it was 0.02 dtex (average fiber diameter 2 μm). The obtained N6 ultrafine fibers were cut into 2 mm lengths to make cut fibers, and then 50 g of the cut fibers and Charol (registered trademark) AN-103P (produced by Daiichi Kogyo Seiyaku Co., Ltd.) which is an anionic dispersant as a dispersant. : 0.5 g of molecular weight 10000) and 500 g of water were charged into an oster blender (manufactured by oster) and stirred for 30 minutes at a rotational speed of 13900 rpm to obtain a dispersion 11 having a N6 ultrafine fiber content of 1.0% by weight. Obtained.

  Table 1 summarizes the dispersions produced in the production examples described above.

<Example 1>
The nanofiber dispersion 1 obtained in Production Example 1 of the dispersion was used, and an SD10 spray dryer manufactured by Mitsui Miike Chemical Co., Ltd. was used as the dryer. The dispersion 1 was dropped onto a 5 cm diameter disk rotating at 9000 rpm at a speed of 20 g / min, and the droplets having a droplet diameter of about 100 μm were sprayed in a 180 ° C. atmosphere and dried (spray). And dried powder was collected.
When the obtained powder was observed by SEM, the number average diameter was 60 nm, and the number average particle diameter of the powder was 25 μm. 1 and 2 show SEM photographs of the powder obtained in Example 1. FIG.
When the obtained powder was applied to the hand, it had a moist feel and was excellent in moisture retention. In addition, the effect of blurring wrinkles on the painted surface was recognized.

<Examples 2 to 10>
About Examples 2-10, it spray-dried like Example 1 using the nanofiber dispersion liquids 2-10 obtained by manufacture examples 2-10 of a dispersion liquid, and obtained powder. The number average diameter of the fiber dispersion and the number average particle diameter of the powder were as shown in Table 2.

<Comparative Example 1>
Spray dispersion was carried out in the same manner as in Example 1 using the dispersion 11 of the ultrafine fiber obtained in Production Example 11 of the dispersion, but the fiber became cottony and a powdery product was not obtained.

<Example 11>
The powder obtained in Example 1 was subjected to pressurized steam treatment for 20 minutes under the conditions of 121 ° C. and 103.7 kPa.
The number average diameter of the fiber dispersion and the number average particle diameter of the powder were as shown in Table 5.
Moreover, it was confirmed by the observation by SEM that the fibers were partially fused and bonded by the pressurized steam treatment. Furthermore, the structure did not collapse even when the powder subjected to the heat steam treatment was immersed in water.

<Example 12>
The powder produced in Example 11 and a commercially available lotion (The Skincare Hydrobalancing Softener (trade name) manufactured by Shiseido Co., Ltd.) were mixed at the following blending ratio for 3 minutes with a lab stirrer to prepare a lotion containing the powder. . When 10 subjects were subjected to a sensory evaluation when using lotion, all the subjects felt that there was no sense of incongruity during use and a natural feeling. Also, by blending the powder, the flow of makeup due to sweat could be prevented, and the makeup lasting was improved. Also, by blending the powder, the powder itself has high water retention, so the moisture retention is good and the moist feeling of the skin after use is improved.

10 wt% of the powder of Example 11
The Skin Care Hydro Balancing Softener 90wt%
Total 100wt%
<Example 13>
Example of nanofiber blended paint 30 g of the powder obtained in Example 11 and 300 g of a commercially available urethane-based paint whose solvent is toluene were stirred with a lab kneader at 120 ° C. for 30 minutes at 30 ° C. to blend nanofibers. A paint was obtained. The obtained paint had good elongation at the time of application with a brush and had an appropriate viscosity, so there was no dripping and it was easy to apply. Moreover, the gloss of the coating after application was good, and the coated surface was smooth despite the addition of fibers.

  Table 2 summarizes the examples and comparative examples described above.

The powder according to the present invention is suitable as a filler for paints and cosmetics, and as a filler for resins.
It is also suitable for adsorbents, water retention agents and the like.
Furthermore, it is also suitable for powder materials in fields such as medical care and hygiene.

2 is a drawing-substituting photograph (500 times) showing the observation result of the powder comprising the fiber dispersion of Example 1 by SEM. FIG. 3 is a drawing-substituting photograph (2000 ×) showing the observation result of the powder composed of the fiber dispersion of Example 1 by SEM.

Claims (10)

A powder composed of ultrafine fibers having a number average particle diameter of 1 to 1000 µm and composed of ultrafine fibers having a number average diameter of 1 to 500 nm. The powder comprising the ultrafine fiber according to claim 1, wherein the ultrafine fiber contains a thermoplastic polymer. The powder according to claim 1 or 2, wherein the fibers are partially bonded to each other. The coating material which mix | blended the powder in any one of Claims 1-3. Cosmetics which mix | blended the powder in any one of Claims 1-3. A process for producing a powder comprising ultrafine fibers, characterized by granulating a fiber dispersion obtained by dispersing ultrafine fibers having a number average diameter of 1 to 500 nm in a dispersion medium, drying the dispersion, and removing the dispersant. The method for producing a powder composed of ultrafine fibers according to claim 6, wherein the fiber dispersion is granulated by spray drying and dried. The method for producing a powder made of ultrafine fibers according to claim 6 or 7, wherein the ultrafine fibers contain a thermoplastic polymer. The method for producing a powder composed of ultrafine fibers according to any one of claims 6 to 8, wherein the ultrafine fibers have a fiber constituent ratio of single fibers having a diameter of more than 500 nm of 3% by weight or less. The method for producing a powder composed of the fiber according to any one of claims 6 to 9, wherein after the dispersion medium is removed, a pressurized steam treatment is further performed.