JP2013053390A - Method for forming composite body of fiber base material and organic nanofiber, and composite body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a composite body including a fiber base material and an organic nanofiber simply and with high productivity, and the composite body.SOLUTION: A carboxylic acid of a guanidyl acetic acid derivative having a structure in which a palmitoyl group is bonded to a guanidyl group portion of Glycocyamine is suspended in water, an equimolar amount of sodium hydroxide is added to the suspension and the obtained matter is heated to 80°C and agitated, and further, sodium chloride is added to the heated and agitated matter to obtain a white organic nanofiber forming compound. A solution in which the white organic nanofiber forming compound is uniformly dissolved is coated on a fiber base material, and the coated fiber base material is dried.

Description

  The present invention relates to a method for forming a composite of a fiber substrate and organic nanofibers, and a composite obtained thereby. More specifically, organic nanofibers formed by self-assembling organic nanofiber-forming compound molecules from a solution in which organic nanofiber-forming compounds are dissolved are formed on the surface and / or inside of various conventionally known fiber substrates. The present invention relates to a composite forming method in which a dense fiber filling structure is obtained by filling the gap between fibers of the fiber base material in a form in which the organic nanofibers are entangled with each other, and a composite obtained thereby.

  In recent years, structures using fine fibers having a fiber diameter on the order of nm have attracted attention as organic nanofibers. For example, by using organic nanofibers with such a fine fiber diameter for filter applications, it is possible to increase the particle capture efficiency while increasing the porosity, and achieve both higher performance filter performance and good air permeability. Therefore, it has attracted particular attention in industrial air filter applications such as home air conditioning filters and high performance filters for clean rooms, or medical applications such as medical masks that can remove bacteria and viruses. .

  Organic nanofibers are formed from organic materials such as those formed from various synthetic fibers, and since the fiber diameter is fine, the structures formed from these are generally weak in strength. In some cases, sufficient mechanical strength may be imparted when used in combination with fiber base materials such as woven fabric, paper, and synthetic paper.

  As a method for forming organic nanofibers most actively studied in recent years, there is a method using an electrospinning method (electrospinning method). In the electrospinning method, when a polymer solution or polymer melt is extruded from a spinning nozzle, a high voltage of 0.5 to 30 KV is applied between the spinning nozzle and the counter electrode, and charges are accumulated in the dielectric in the nozzle. By doing so, fine fibers are produced with an electrostatic repulsive force, whereby organic nanofibers can be adhered onto the fiber substrate. Patent Documents 1 to 4 describe a method of forming an organic nanofiber layer on the surface of a base material, particularly when a nonwoven fabric base material is used as a fiber base material by utilizing such an electrospinning method.

  The biggest drawback of the electrospinning method is that productivity is poor, the spinning speed is low, and it is difficult to efficiently form a layer made of organic nanofibers produced thereby. Furthermore, by performing electrospinning on the fiber substrate surface, a layer of organic nanofibers spun on the fiber substrate surface is formed, but interactions such as physical entanglement occur with the fiber substrate. Since it is difficult, the adhesiveness with the fiber base material is poor, and problems of adhesion failure such as dropping of organic nanofibers from the surface of the fiber base material may be pointed out. In addition, since the organic nanofibers are not introduced into the fiber base material, the organic nanofibers remain only on the fiber base material surface and are not introduced into the base material. In addition, the fibers forming the organic nanofibers produced by the electrospinning method have a problem in that sufficient mechanical strength and chemical stability cannot be exhibited because the crystallinity is lowered.

  For such a problem, for example, Patent Document 5 discloses that organic nanofibers formed in advance are dispersed in a solvent, and a nonwoven fabric base material is used as a fiber base material. A method for introducing nanofibers is disclosed. In this method, if the fiber length of the organic nanofiber is short, a coating solution having relatively good dispersibility can be prepared and introduced into the substrate relatively uniformly. However, the fiber length of the organic nanofiber is short. As the result, the bondability with the substrate deteriorates, and there is a problem that the organic nanofibers fall off from the substrate, and the entanglement between the organic nanofibers decreases and the filter performance also deteriorates. Conversely, when organic nanofibers with a long fiber length are used, it becomes extremely difficult to disperse organic nanofibers, and the concentration of organic nanofibers in the dispersion must be kept below 1%. In addition, there is a problem that it is difficult to introduce organic nanofibers into the inside of the base material because of the low introduction rate of the base material and the filter function of the base material itself.

  As organic nanofibers introduced into the surface and / or inside of the fiber substrate, for example, it is considered possible to use organic nanotubes as described in Patent Documents 6 to 9, for example. It is difficult to introduce such organic nanotubes on the fiber substrate surface or inside due to poor dispersibility therein. As a method for improving the dispersibility of organic nanotubes, Patent Document 10 discloses a method of cutting organic nanotubes by stirring to shorten the fiber length to 10 μm or less. In this method, the fiber length is short, and in particular, a short fiber of 1 μm or less is often generated. Even if an attempt is made to form a complex with the fiber substrate targeted by the present invention, short organic nanotubes fall off the complex. There is a problem that cannot be used because it becomes easy to do.

  Therefore, there has been a demand for a simple and highly productive method for forming a composite composed of a fiber base material and organic nanofibers. Particularly, the fiber diameter is in the range of 10 to 1000 nm, and the fiber length By simply introducing nanofibers having a diameter of 10 μm or more into the surface and / or inside of the fiber base material, and filling the gaps between the fibers formed by the original fiber base material with a fiber structure in which the organic nanofibers are intertwined Therefore, a composite forming method and a composite that can provide a dense fiber-filled structure have been desired.

JP 2008-169521 A JP 2010-94962 A JP 2010-144280 A Special table 2011-508113 gazette JP 2005-330639 A JP 2002-322190 A JP 2004-224717 A JP 2008-30185 A JP 2004-250797 A JP-A-2005-96014

  As a method for forming a composite composed of a fiber base material and organic nanofibers and a composite, an organic nanofiber having a fiber diameter in the range of 10 to 1000 nm and a fiber length of 10 μm or more is used. A composite forming method and a composite that can be easily introduced into the interior and fill a gap between fibers formed by the original fiber base with a fiber structure in which the organic nanofibers are intertwined to obtain a dense fiber-filled structure. Giving.

  The problem of the present invention is basically solved by a method for forming a composite of a fiber base material and an organic nanofiber by applying a solution in which an organic nanofiber-forming compound is dissolved to the fiber base and drying the composite, and the composite obtained thereby. Is done. Furthermore, a solution in which an organic nanofiber-forming compound is dissolved is applied onto a fiber substrate, the applied liquid is cooled prior to drying, and the gelated coating liquid is dried, and the composite obtained thereby Solved by the body. Moreover, the organic nanofiber-forming compound is solved by a composite forming method in which the compound is represented by the following general formula I and a composite obtained thereby.

In the formula, R ₁ represents a hydrocarbon group having 6 to 29 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group. M ⁺ represents an alkali metal ion.

  As a composite forming method and composite comprising a fiber base material and organic nanofibers, an organic nanofiber having a fiber diameter in the range of 10 to 1000 nm and a fiber length of 10 μm or more is used on the surface and / or inside of the fiber base material. And a composite forming method and composite in which a dense fiber-filled structure is obtained by filling the gap between the fibers formed by the original fiber base material with a fiber structure in which the organic nanofibers are entangled with each other. It is done.

The enlarged photograph which observed the nonwoven fabric used in Example 1 with the confocal laser microscope. The enlarged photograph which observed the composite_body | complex of the nonwoven fabric and organic nanofiber obtained in Example 1 with the confocal laser microscope. The observation image by the scanning electron microscope of the composite_body | complex of the nonwoven fabric obtained in Example 4 and organic nanofiber. Magnification 100 times. The observation image by the scanning electron microscope of the composite_body | complex of the nonwoven fabric obtained in Example 4 and organic nanofiber. Magnification 1000 times. The observation image by the scanning electron microscope of the composite_body | complex of the nonwoven fabric obtained in Example 4 and organic nanofiber. Magnification 4000 times. The observation image by the scanning electron microscope of the composite_body | complex of the nonwoven fabric obtained in Example 4 and organic nanofiber. Magnification 20000 times.

  In the present invention, as a method for forming a composite of a fiber substrate and organic nanofibers, a solution in which an organic nanofiber-forming compound is uniformly dissolved is applied onto the fiber substrate and dried. The present invention is a method in which organic nanofiber-forming compound molecules are spontaneously self-assembled by such a complex formation method, and organic nanofibers formed thereby are formed on the surface of the fiber substrate or inside the fiber substrate. Further, the composite formed in this way is characterized by having a very dense fiber-filled structure that has not been obtained by conventional methods.

  As the fiber base material used in the present invention, any of nonwoven fabric, woven fabric, paper, synthetic paper and the like can be preferably used. Among these, in particular, the nonwoven fabric can be freely selected from a wide range of fiber materials, and the fiber diameter and fiber length can be selected to some extent, and the fiber density (basis weight) or different. It can be most preferably used because it has a high degree of freedom among fiber base materials such as a composite using fibers, and if necessary, various fillers are introduced into the nonwoven fabric to incorporate further functionalization.

  The organic nanofiber in the present invention is an organic nanofiber having a diameter of 1000 nm or less, preferably 10 to 1000 nm and a length of 10 μm or more, and these organic nanofibers are intertwined with each other. As a composite that forms a dense fiber-filled structure in which a gap between fibers formed by the original fiber base material is filled with a fiber structure in which the organic nanofibers are intertwined on the surface and / or inside of the fiber base material. It is characteristic that it is formed.

  The organic nanofiber-forming compound used in the complex forming method of the present invention is in a state of being completely dissolved in a molecular form in the solution, but the molecules self-assemble in the process of cooling or drying the solution, It means a compound that spontaneously forms organic nanofibers. Examples of compounds exhibiting such properties include various examples as shown in the above-mentioned Patent Documents 6 to 9, which have been conventionally known as organic nanotubes. Among them, a glycylglycine type compound or an N-glycoside type glycolipid in which an acyl group having a long chain alkyl group is bonded to the terminal amino group of glycylglycine described in Patent Document 8 and the like can be preferably used. These compounds are soluble in a mixed solvent of ethyl acetate and alcohol such as methanol, or a single solvent of alcohol. By drying from these solutions using, for example, a rotary evaporator, compound molecules are spontaneously assembled from the solution. To form organic nanofibers. In the present invention, as shown in the examples described later, organic nanofibers having a fiber length of 10 μm or more are formed on the surface of the fiber substrate by applying these solutions to the fiber substrate and drying. And / or is simply introduced into the interior, and the gap between the fibers formed by the original fiber base material is filled with a fiber structure in which the organic nanofibers are entangled to form a complex that forms a dense fiber-filled structure. I found out that it would be possible.

  In the above method, since the solvent for dissolving the organic nanofiber-forming compound is an organic solvent, there is a concern about adverse effects on safety and health in production. Therefore, the compound is used without using an organic solvent and using water. The method of dissolving is more preferable. However, the compounds shown in the above examples do not necessarily have good solubility in water, and are generally difficult to dissolve uniformly unless used at a concentration of 1% by mass or less and the liquid temperature is heated to 90 ° C. or higher. Furthermore, when the aqueous solution prepared in such a concentration and temperature condition is applied to the fiber substrate and dried, the solution is slowly cooled over time, and the organic nanofibers are extracted from the solution. It is necessary to perform drying after the organic nanofibers are formed on the fiber base material by utilizing the fact that the liquid crystallizes and loses fluidity to form a gel.

  By using the organic nanofiber-forming compound represented by the following general formula I with respect to the above compound, the solubility of the compound in water becomes extremely good, and when dried or cooled from the solution, By forming an organic nanofiber, a solution in which a compound of the following general formula I is dissolved is applied to a fiber base material, and then dried to obtain an organic nanofiber having a fiber length of 10 μm or more. A composite that forms a dense fiber-filled structure by simply introducing it into the surface and / or inside of the fiber and filling the gap between the fibers formed by the original fiber base material with a fiber structure in which the organic nanofibers are entangled with each other. It is extremely preferable because it can be formed most simply.

In the formula, R ₁ represents a hydrocarbon group having 6 to 29 carbon atoms, and R ₂ represents a hydrogen atom or a methyl group. M ⁺ represents an alkali metal ion. The hydrocarbon group for R ₁ may be an alkyl group which may be branched or a hydrocarbon group containing an unsaturated bond group, but is preferably a linear alkyl group having 6 to 29 carbon atoms or a carbon group having 6 carbon atoms. It is a case where it is -29 and it is a hydrocarbon group containing 1-4 unsaturated bond groups. Further, it is most preferable that the alkali metal ion of M ⁺ is sodium ion, potassium ion or lithium ion.

  The organic nanofiber-forming compound represented by the general formula I can be synthesized by various known synthesis methods such as, for example, reacting a carboxylic acid and an amine in the presence of a condensing agent. In this case, water is used as a reaction solvent, and a so-called Schotten-Baumann reaction (for example, a reaction in which acid chloride and glycosamine (guanidinoacetic acid) or creatine are reacted in the presence of a base such as sodium hydroxide or various organic amines in water (for example, When using March's Advanced Organic Chemistry, Fifth Ed., John Wiley & Sons, Inc., (2001) P. 506) as the literature, it is the most convenient, inexpensive, high yield and high purity. It is preferable because a compound is obtained. As shown in the examples described later, an aqueous solution in which an acid chloride of a fatty acid having 7 to 30 carbon atoms is used as an acid chloride, and a base such as glycosiamine or creatine and sodium hydroxide is suspended or dissolved in water. It is preferable to gradually add acid chloride therein.

Examples of the acid chloride that can be preferably used in the above include heptanoyl chloride, octanoyl chloride, nonanoyl chloride, decanoyl chloride, undecanoyl chloride, lauroyl chloride, tridecanoyl chloride, myristoyl chloride, pentadecanoyl chloride, Saturated fatty acid chlorides such as palmitoyl chloride, stearoyl chloride, nonadecanoyl chloride, eicosanoyl chloride, docosanoyl chloride, tetracosanoyl chloride, hexacosanoyl chloride, heptacosanoyl chloride, octacosanoyl chloride, triacosanoyl chloride Or examples of unsaturated fatty acid chlorides include 6-heptenoyl chloride, 2-octenoyl chloride, Silenoyl chloride, oleoyl chloride, elidoyl chloride, cis-11-eicosenoyl chloride, linoleoyl chloride, linolenoyl chloride, arachidonoyl chloride, 2-heptinoyl chloride, 2-octinoyl chloride, etc. are preferred As an example. Among these, lauroyl chloride, myristoyl chloride, palmitoyl chloride, stearoyl chloride, oleoyl chloride and the like having 12 to 18 carbon atoms are easily available and inexpensive, and the organic nanofibers of the present invention obtained from these are available. It can be most preferably used for reasons such as good solubility of the forming compound. Therefore, as R ₁ represented by the general formula I, a case where it is a saturated or unsaturated hydrocarbon group having 11 to 17 carbon atoms can be most preferably used.

  The above various acid chlorides can be used in the reaction alone or diluted in an organic solvent that does not react with acid chlorides such as acetone, tetrahydrofuran, and 1,4-dioxane. As the method of adding acid chloride, a method of gradually adding it into an aqueous solution over a period of several tens of minutes to several hours using a dropping funnel or the like with respect to an aqueous solution in which glycosylamine or creatine is dissolved or suspended is preferably performed. .

  In the above reaction, the reaction is carried out using equimolar amounts of acid chloride, glycosiamine or creatine and a base such as sodium hydroxide, and the pH of the system shifts from neutral to weakly acidic as the reaction proceeds. The product is precipitated in the form of a carboxylic acid derivative by adding an acid, if necessary, and separated from the reaction system by a method such as filtration, and then an equimolar amount of a base is added to obtain the desired general formula I The method of synthesizing the organic nanofiber-forming compound represented by is most preferable. In this case, if necessary, purification is performed by recrystallization from a solvent such as alcohol in the state of a carboxylic acid derivative in the middle, and then an equimolar amount of base is added to obtain the target organic compound represented by the general formula I. A method for obtaining a nanofiber-forming compound can also be preferably used.

  As side reactions occurring in the above reaction, there are cases where hydrolysis of acid chloride with an alkali or by-product formation of an acid anhydride caused by reaction of acid chloride with a carboxylic acid moiety of glycosamine or creatine may occur. In particular, when the reaction system is not sufficiently stirred due to the product precipitated in the middle of the reaction, the hydrochloric acid produced by the reaction is not neutralized by the base in the aqueous solution, and a large amount of acid anhydride is produced. May be generated.

  In order to suppress the side reaction as described above and obtain the target carboxylic acid derivative in a high yield, in the present invention, the reaction temperature for reacting acid chloride with glycosylamine or creatine is 0-10. The reaction may be carried out at a relatively low temperature of 0 ° C., but more preferably when the reaction is carried out in the range of 40 ° C. to 80 ° C., the carboxylic acid derivative can be obtained with the highest yield and high purity. . That is, normally, in order to avoid hydrolysis of the acid chloride to be used by alkali, when performing the Schotten-Baumann reaction, the reaction is usually performed at a low temperature of about 0 to 10 ° C. In the invention as well, the reaction can be carried out in the range of 0 ° C. to 10 ° C. to obtain the desired carboxylic acid derivative. In this case, it is preferable to sufficiently slow down the addition rate of the acid chloride to be added, and it is usually preferable to add the acid chloride over a period of about 2 to 6 hours. When the reaction is carried out by adding acid chloride at a faster rate than this, a side reaction giving an acid anhydride may occur remarkably. This is considered to be due to the fact that the solubility of glycosylamine or creatine in water is low at low temperatures and the reaction proceeds in a heterogeneous state in which glycosylamine or creatine is suspended. On the other hand, when the reaction temperature is in the range of 40 ° C. to 80 ° C., the solubility of glycosylamine or creatine in water is remarkably increased, and the reaction is carried out in a homogeneous system in the form of dissolved glycosylamine or creatine salt. Therefore, it is considered that the acylation reaction with respect to the nitrogen atom occurs preferentially. In this case, the acid chloride may be added over a period of about 30 minutes to 2 hours, or over a longer time for the purpose of avoiding an excessive increase in the reaction temperature. May be performed.

The compound of the general formula I obtained in the present invention is soluble in hot water, and the temperature for dissolving in water gradually increases as the number of carbons contained in the substituent R ₁ increases. As shown in the examples described later, for example, in the case of an alkyl group having 11 carbon atoms in the substituent R ₁ , it dissolves uniformly at a temperature around 40 ° C., but in the case of an alkyl group having 17 carbon atoms. In this case, a uniform solution can be obtained by heating to a temperature around 80 ° C. When the aqueous solution that has been dissolved and becomes uniform is cooled, nanofibers are deposited. In this case, the cooling rate may be arbitrary, whether it is rapidly cooled or cooled slowly over a long period of time, the same organic nanofiber and the assembly of organic nanofibers in which these are assembled The body can be formed. The change in the system is a sol-gel transition because the organic nanofibers formed in the solution lose its fluidity and gel. At this time, the concentration of the organic nanofiber-forming compound in the solution is preferably 0.1% by mass or more. When the concentration is higher than this concentration, sol-gel transition is observed, and the solution of the organic nanofiber-forming compound is dried. Or it was recognized that organic nanofiber aggregates were formed without problems by cooling.

  As described in Examples below, an organic nanofiber formed by cooling an organic nanofiber-forming compound of the general formula I and an aggregate thereof, or an organic nanofiber-forming compound of the general formula I The shapes of the organic nanofibers immediately formed by drying from the dissolved solution and the aggregates thereof are the same, and when observed with an optical microscope and an electron microscope, the diameter is in the range of 10 to 1000 nm, and the length Was found to be an organic nanofiber having a thickness of 10 μm or more and an aggregate thereof. Furthermore, when each organic nanofiber was observed in detail with a transmission electron microscope, no particular change was observed in the electron beam transmission density in the contour of the organic nanofiber. If the hollow structure is used, the electron beam transmission at the contour portion is reduced. Therefore, the organic nanofiber obtained using the organic nanofiber-forming compound of the general formula I is not recognized as having a hollow structure, and has a density of It is assumed that it shows a uniform, possibly β-sheet-like structure.

  In contrast, a glycylglycine type compound or an N-glycoside type glycolipid in which an acyl group having a long-chain alkyl group is bonded to the terminal amino group of glycylglycine described in the above-mentioned Patent Document 8 or the like. When the composite according to the present invention is formed in the same manner, the organic nanofiber contained therein has a hollow structure, and in addition to the shape as a fiber, there are uses utilizing the hollow portion inside. Although it is conceivable, in the present invention, since the properties of the organic nanofibers are merely used, whether or not the inside of the fiber is hollow is not particularly problematic and can be used in the same manner.

  In order to form organic nanofibers on a fiber substrate, a solution in which an organic nanofiber-forming compound is uniformly dissolved is used as a coating solution. A composite made of fibers can be formed. At this time, the concentration of the organic nanofiber-forming compound used in the coating in the solution is preferably 0.1% by mass or more. When the concentration is higher than this concentration, the organic nanofibers are present on the surface and / or inside of the fiber substrate. The introduced complex is formed without problems.

  In addition, when the coating solution is applied onto the fiber substrate, it may be dried immediately after coating to form a dried organic nanofiber on the substrate. Alternatively, the coating solution may be dried. Before arriving, the applied liquid may be cooled to a temperature between −20 ° C. and 20 ° C. for gelation to deposit organic nanofibers on the substrate, followed by drying. When the composite is formed in the latter manner, a structure in which the organic nanofibers are entangled more uniformly can be formed in the gaps between the fibers of the fiber base material. In particular, when the opening between the fibers of the fiber base material is relatively large, when the coating liquid is applied and dried immediately, organic nanofibers are formed along the fiber base material to constitute the fiber base material. The density of the organic nanofibers filled in the gaps between the fibers may decrease.

  The drying temperature is preferably in the range of 0 ° C. to 120 ° C., and any drying temperature can be set as long as the temperature is in this range. Regarding the drying speed, the air may be blown as quickly as possible, or the drying may be slowly performed over a long time depending on the case.

  The coating solution may further contain alcohols and various water-miscible organic solvents. Alternatively, it may be a coating solution that does not contain water and uses various organic solvents such as esters such as alcohol and ethyl acetate, ketones such as acetone, and cyclic ethers such as dioxane and tetrahydrofuran, most preferably A case where the organic solvent is not substantially contained (less than 5% by mass) and is an aqueous solution is preferable.

  Furthermore, various surfactants may be contained in the coating solution. Alternatively, in addition to the organic nanofiber-forming compound, various hydrophilic resins and emulsions may be added in an amount range that does not exceed this in order to increase the adhesion between the nonwoven fabric substrate and the organic nanofiber. It may be used as a coating solution. Examples of hydrophilic resins include gelatin, gelatin derivatives (for example, phthalated gelatin), hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene oxide, xanthan, cationic hydroxyethyl cellulose, polyvinyl alcohol, A hydrophilic resin such as polyacrylamide is preferred. As the emulsion, various acrylic emulsions, vinyl acetate emulsions, styrene-acrylic emulsions, vinylidene chloride emulsions and the like can be preferably used.

  Various conventionally known coating methods can be used as a coating method when the above-mentioned coating solution is coated on the fiber base material. For example, a gravure coating method in which a coating liquid is fed to the surface of a coating roll and this is transferred to a fiber substrate, or a kiss coating method, a blade coating method, etc. can be used, preferably spray coating or fountain coating, A method in which the coating apparatus such as slide coating, curtain coating, and slot die coating method is not in direct mechanical contact with the fiber substrate, and only the coating solution is fed onto the fiber substrate. Furthermore, an impregnation process (dip coating method) in which the fiber base material is impregnated in the coating liquid can also be preferably performed. In this case, in order to remove excess liquid from the fiber base material impregnated with the coating liquid, A method of squeezing liquid between rolls following the impregnation step, a method of scraping off excess liquid with a doctor blade, a method of using an air blade for the same purpose, etc. are preferably used.

  There is a preferred range for the coating amount of the coating solution applied onto the fiber substrate by the above-described coating or the adhesion amount of the organic nanofibers to the fiber substrate. Regarding the coating amount of the coating liquid, there is a preferable range for each of the various coating methods described above, but the coating amount per unit square meter of the fiber base material is 1 as the moisture coating amount for any of the coating methods. When it is in the range of ˜100 g, it can be applied most uniformly, and further, it is preferable because drying can be performed quickly in drying. A more preferable application amount range is a case where the moisture application amount per unit square meter of the fiber base is in the range of 5 to 50 g. The concentration of the organic nanofiber forming compound contained in the coating solution is preferably 0.1% by mass or more, and when the concentration exceeds 20% by mass, the fiber density of the formed organic nanofiber is increased. In the composite formed, the organic nanofibers are almost completely filled in the voids of the fiber base, and the porosity may be significantly reduced. The preferable concentration of is in the range of 0.1 to 20% by mass. The preferable range of the adhesion amount of the organic nanofibers to the fiber base material is 0.001 to 20 g, more preferably 0.005 to 10 g, as the dry solid content per square meter of the fiber base unit.

  Next, the nonwoven fabric that can be most preferably used as the fiber base material in the present invention will be described. Regarding the material of the fibers forming the nonwoven fabric, various fibers used in general nonwoven fabrics can be used. Specifically, plant-derived natural fibers such as cotton, hemp and cellulose pulp, and animal-derived natural fibers such as wool and silk. , Rayon, vinylon, poval, nylon, polyester, polylactic acid, polyurethane, polyethylene, polypropylene, acrylic, aramid and other chemical fibers, glass fibers, carbon fibers, metal fibers, and the like. These fibers can each be used alone or a non-woven fabric produced by combining a plurality of these can be preferably used as the fiber base material in the present invention.

  As the nonwoven fabric that can be most preferably used in the present invention, the diameter and length of the fibers forming the nonwoven fabric are in the range of 1 to 100 μm as the fiber diameter and 1 mm as the fiber length to ensure a certain degree of strength. The case where the fiber length is infinite from the above short fibers is preferable.

  As a manufacturing method for forming the above-mentioned nonwoven fabric, those according to various conventional manufacturing methods are used. Specifically, a dry method using an air flow, a wet method using a water flow, and a molten fiber. The spunbond method, melt blown method, etc., used as the manufacturing method, and the method of bonding the fibers constituting the nonwoven fabric include the chemical bond method using an adhesive, the thermal bond method using thermal fusion, and the needle Various methods such as a needle punching method in which fibers are entangled by using protrusions to be engraved and a spunlace method using high-pressure water flow can be used. Combining non-woven fabrics manufactured by using these various methods alone, and non-woven fabrics manufactured by combining them, such as the spunbond method (S) and meltblown method (M), which are called SMS non-woven fabrics It is also possible to use a composite nonwoven fabric as manufactured.

The thickness and density of the nonwoven fabric that can be most preferably used in the present invention are not particularly limited, but preferably the thickness is in the range of 50 μm to 2 mm, and the basis weight or basis weight (mass per unit area) is 10. The range of ˜500 g / m ² is preferable because it is the easiest to handle in production.

  As the nonwoven fabric that can be used in the present invention, a nonwoven fabric using a fiber having hydrophilicity imparted by a surfactant to the fiber surface constituting the nonwoven fabric, a nonwoven fabric subjected to water repellent treatment, or a corona discharge treatment is performed. Thus, when the surface of the fiber is modified, or a nonwoven fabric subjected to various treatments such as a flame retardant treatment or a charging treatment treatment can be preferably used.

  As the non-woven fabric that can be used in the present invention, base materials processed into various shapes such as dyeing, laminating, coating, or corrugating may be used. Most preferably, the nonwoven fabric can be used in the form of a sheet, wound from a roll as a web, formed into a composite according to the present invention, and then dried and wound into a roll. Is most preferred.

  EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the percentage in an Example is a mass reference | standard unless there is a notice.

(Synthesis Example 1) Synthesis Example of Compound of General Formula I (When R ₁ has 15 Carbons)
In a 500 ml round bottom flask equipped with a nitrogen introduction tube, a thermometer, a reflux condenser, and a dropping funnel, 23.4 g of glucosamine (Tokyo Chemical Industry reagent) was weighed, and 300 ml of water was added and stirred. To this was added 13.2 g of potassium hydroxide (purity 85%), and the internal temperature was raised to 50 ° C. on a water bath. A solution in which 30 g of acetone was added to 55 g of palmitoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was introduced into the dropping funnel and placed under a nitrogen stream. The palmitoyl chloride solution was added dropwise from the dropping funnel over 1 hour. After completion of the dropwise addition, the internal temperature was kept at 50 ° C. for 1 hour and stirring was continued. The pH of the reaction system changed from neutral to weakly acidic, and then the precipitated product was separated by suction filtration, sufficiently washed with water and dried. As a result of analyzing the purity and structure of the product using HPLC and ¹ H-NMR, it became clear that the product was a guanidyl acetic acid derivative having a structure in which a palmitoyl group was bonded to the guanidyl group part of glucosylamine with almost 100% purity. It was. The product carboxylic acid was suspended in water, an equimolar amount of sodium hydroxide was added, and the mixture was heated and stirred at 80 ° C. to obtain a uniform solution. By adding sodium chloride to this solution, a white precipitate immediately formed, and when cooled, the whole gelled. The whole is transferred onto a glass filter, washed with ethyl acetate while performing suction filtration, and the solid matter on the filter is dried in a vacuum dryer to obtain the desired compound of general formula I (carbon number of R ₁ Is 15 and M ⁺ is a sodium ion) in 80% yield.

Synthesis Example 2 Synthesis Example of Compound of General Formula I (When R ₁ has 11 Carbons)
The reaction was carried out in the same manner as in Synthesis Example 1 except that 0.2 mol of lauroyl chloride was used instead of palmitoyl chloride in Example 2 as the acid chloride, and R _{1 represented} by general formula I had 11 carbon atoms. Thus, a target compound in which the alkali metal ion is sodium ion was obtained. The reaction yield was 85%.

Example 1
As the fiber substrate, a non-woven fabric having a thickness of 120 μm and a basis weight of 100 g / m ² including polyester fiber and acrylic fiber at a mass ratio of 60:40 was used. Using the compound of the general formula I obtained in Synthesis Example 1 (the compound having 15 carbon atoms of R ₁ ), water is added so that the solid content concentration becomes 1% by mass, and the mixture is heated to 80 ° C. to be a uniform solution Was made. A 1 liter solution prepared by adjusting the solution to 65 ° C. was prepared and used as a coating solution. The above-mentioned nonwoven fabric was impregnated in a stainless steel bat charged with the coating solution, impregnated for 10 seconds, the nonwoven fabric was pulled up, and excess liquid was sandwiched between two rolls and removed by squeezing. The moisture application amount of the coating liquid introduced onto the nonwoven fabric at this time was about 30 g per square meter. Next, the nonwoven fabric impregnated with the coating solution was placed inside the refrigerator, left for 2 minutes at a temperature of 10 ° C., and then taken out and dried using a blower dryer adjusted to 50 ° C. The adhesion amount of the organic nanofiber introduced into the nonwoven fabric was 0.3 g per square meter of the nonwoven fabric in terms of dry solid content. FIG. 1 shows an enlarged photograph of a non-woven fabric before impregnation processing observed using a confocal laser microscope, and FIG. 2 shows a composite of the nonwoven fabric and organic nanofibers obtained after the above impregnation processing and drying. An enlarged photograph of was shown. As is clear from these figures, it was found that a fine fiber-filled structure was formed so as to fill the gap between fibers of the original nonwoven fabric. From the micrograph, it was found that the fiber diameter of the organic nanofiber was in the range of 10 to 1000 nm and the fiber length was 10 μm or more.

(Example 2)
Using the same nonwoven fabric and coating solution as in Example 1, the coating solution was similarly impregnated with the nonwoven fabric. Similarly, the nonwoven fabric substrate was taken out from the coating solution, squeezed in the same manner to remove the excess coating solution, and then immediately dried using a blast dryer adjusted to 50 ° C. The adhesion amount of the organic nanofiber introduced into the nonwoven fabric was 0.3 g per square meter of the nonwoven fabric in terms of dry solid content. When the obtained sample was observed using a confocal laser microscope in the same manner as in Example 1, as in Example 1, a fine fiber-filled structure was formed so as to fill the inter-fiber gap of the original nonwoven fabric substrate. I found out. However, it was observed that the filling of the organic nanofibers was slightly less at the locations where the interfiber gaps were wide, and the packing density was relatively high at the portion where the fiber density of the fiber substrate was high. From the micrograph, it was found that the fiber diameter of the organic nanofiber was in the range of 10 to 1000 nm and the fiber length was 10 μm or more.

(Example 3)
Using N-tetradecanoyl-glycylglycine synthesized in Example 4 of Patent Document 8 and adjusting this to 40 ° C. as shown in Example 7 of the same publication, ethanol and chloroform 1: A coating solution was prepared by dissolving in 1 mixed solvent so that the solid concentration was 0.5 mass%. The nonwoven fabric substrate used in Example 1 was impregnated in the same manner as in Example 1, and squeezed in the same manner to remove excess coating solution. At this time, the coating amount of the coating solution introduced into the nonwoven fabric substrate was approximately 20 g per square meter. Drying was performed naturally at room temperature. After observing the sample after 3 hours, it was confirmed that the drying was completed. When the sample was observed using a confocal microscope, a fine fiber-filled structure was formed in the form of filling the gap between fibers of the original nonwoven fabric substrate. It was found that it was formed. From the micrograph, it was found that the fiber diameter of the organic nanofiber was in the range of 10 to 1000 nm and the fiber length was 10 μm or more. The amount of organic nanofibers attached per square meter of the nonwoven fabric substrate was 0.1 g.

Example 4
As the nonwoven fabric substrate, a nonwoven fabric substrate having a thickness of 200 μm and a basis weight of 70 g / m ² including core-sheath fibers and polypropylene fibers each composed of polypropylene and polyethylene at a mass ratio of 80:20 was used. Using the compound of the general formula I obtained in Synthesis Example 2 (the compound having 11 carbon atoms of R ₁ ), water is added so that the solid content concentration is 2% by mass, and the mixture is heated to 40 ° C. to be a uniform solution Was made. A 1 liter solution prepared by adjusting the solution to 40 ° C. was prepared and used as a coating solution. The coating solution was sprayed onto the surface of the nonwoven fabric substrate in a mist form from a spray nozzle for spray coating, and was immediately dried using a blast dryer adjusted to 50 ° C. From the increase in the mass of the nonwoven fabric substrate after drying, it was found that the amount of organic nanofiber attached was about 0.6 g per square meter of nonwoven fabric in terms of dry solid content. When the sample was observed using a confocal microscope, it was found that a fine and very dense fiber-filled structure was formed so as to fill the gap between the fibers of the original nonwoven fabric substrate. Further observation using a scanning electron microscope revealed that a very fine fiber-filled structure was formed so as to fill the gaps between the fibers of the original nonwoven fabric substrate, as shown in FIGS. It was. The thick fibers recognized in FIG. 3 and FIG. 4 are derived from the nonwoven fabric substrate used, and in the observation at a low magnification in FIG. 3, it can be seen that a film is formed so as to fill the space between the thick nonwoven fibers, As it was enlarged, it was observed that the membrane had a dense packing structure with fibrous organic nanofibers and pores were formed, as clearly shown in FIGS. 5 and 6. From the micrograph, it was found that the fiber diameter of the organic nanofiber was about 100 nm and the fiber length was 10 μm or more.

  Since a fine fiber filling structure using a nanofiber aggregate can be introduced into a nonwoven fabric substrate, it can be applied to various filters, separation membranes, adsorbents, pharmaceuticals, and medical uses.

Claims (5)

  A method for forming a composite of a fiber base material and an organic nanofiber, wherein a solution in which an organic nanofiber forming compound is dissolved is applied onto a fiber base material and dried.   The composite of a fiber substrate and organic nanofibers according to claim 1, wherein a solution in which the nanofiber-forming compound is dissolved is applied onto the fiber substrate, the applied solution is cooled prior to drying, and the gelated coating solution is dried. Body formation method. The method for forming a composite of a fiber substrate and organic nanofibers according to claim 1 or 2, wherein the organic nanofiber-forming compound is a compound represented by the following general formula I.
(In the formula, R ₁ represents a hydrocarbon group having 6 to 29 carbon atoms, R ₂ represents a hydrogen atom or a methyl group, and M ⁺ represents an alkali metal ion.)   The said fiber base material is a nonwoven fabric, The composite formation method of the fiber base material and organic nanofiber as described in any one of Claims 1-3.   The composite_body | complex obtained by the composite formation method of the fiber base material and organic nanofiber described in any one of the said Claims 1-4.