WO2015162676A1 - Porous material and porous sheet - Google Patents

Abstract

Provided are a porous material and porous sheet which use a fibroin porous body that exhibits excellent handling properties and slicing properties, and is flexible even in a dry state. The porous material is characterized in that the fibroin porous body contains 20-75 mass% of a hydroxyl-group-containing compound having a molecular weight of 1,000 or less.

Description

Porous material and porous sheet

The present invention relates to a porous material and a porous sheet obtained using a fibroin porous material.

Porous materials that can be produced using biological substances such as proteins and sugars are used in cosmetics and esthetics for the purpose of moisturizing and other purposes for esthetic salons and individuals, wound dressings, sustained release carriers for drugs, etc. Medical field, daily necessities such as disposable diapers, sanitary products, water purification field that can be used as a support for living organisms such as microorganisms and bacteria, tissue culture that can be used as a cell culture support (scaffold material), tissue regeneration support, etc.・ Used in a wide range of industrial fields such as regenerative medical engineering.
As biologically-derived substances constituting these porous bodies, saccharides such as cellulose and chitin, protein groups such as collagen, keratin, and fibroin are known.

Of these bio-derived substances, fibroin, especially silk fibroin, is industrially used from the viewpoint of stable supply of raw materials and price stability. Furthermore, it has a track record of being used as a surgical suture for a long time other than clothing, and has recently been used as an additive for foods and cosmetics. Since silk fibroin has no problem with respect to safety to the human body, its use for porous materials has been studied.
There are several reports on the technique for producing silk fibroin porous materials. For example, a method in which a silk fibroin aqueous solution is rapidly frozen and then immersed in a crystallization solvent and melted and crystallized at the same time (Patent Document 1). (Patent Document 2), a method of producing a porous material by adding a small amount of a water-soluble organic solvent to a silk fibroin aqueous solution, and then freezing and melting for a certain time to obtain a silk fibroin porous material. Yes (Patent Document 3).

JP-A-8-41097 JP 2006-249115 A Japanese Patent No. 3412014

The porous body produced by the above method is soft in a wet state containing water, but is brittle in a dry state where water is removed by drying such as freeze-drying, and is inferior in workability and appearance due to generation of cracks, etc. was there.
An object of the present invention is to provide a porous material and a porous sheet using a fibroin porous body that is soft even in a dry state and excellent in appearance after drying and slice processability.

As a result of intensive studies to achieve the above problems, the present inventor has found that the problems can be solved by the following invention.
[1] A porous material, wherein the fibroin porous material contains 20 to 75% by mass of a hydroxyl group-containing compound having a molecular weight of 1,000 or less.
[2] The hydroxyl group-containing compound is selected from glycerin, polyglycerin, polyethylene glycol, triethyl citrate, lactic acid, polyvinyl alcohol, propylene glycol, butylene glycol, alcohol, glycerin fatty acid ester, polyglycerin fatty acid ester, and sorbitan fatty acid ester. [1] The porous material according to [1].
[3] The porous material according to [1], wherein the hydroxyl group-containing compound is glycerin.
[4] A porous sheet made of the porous material according to any one of [1] to [3] and having a thickness of 0.1 to 50 mm.

The porous material and the porous sheet according to the present invention are soft even in a dry state, and are excellent in appearance after drying and slicing workability.

2 is a photograph showing the appearance after drying of the porous material produced in Example 1. FIG. 2 is a photograph showing the appearance of a porous sheet obtained by slicing the porous material produced in Example 1. FIG. 2 is a photograph showing the appearance of a porous material produced in Comparative Example 1 after drying. 4 is a photograph showing the appearance of a porous sheet obtained by slicing the porous material produced in Comparative Example 1. FIG. 5 is a photograph showing the appearance after drying of the porous material produced in Comparative Example 2. 5 is a photograph showing the appearance of a porous sheet obtained by slicing the porous material produced in Comparative Example 2. FIG.

The porous material according to the present invention is characterized in that the fibroin porous body contains 20 to 75% by mass of a hydroxyl group-containing compound having a molecular weight of 1,000 or less. That is, in the porous material of the present invention, the fibroin porous body holds the hydroxyl group-containing compound.

The hydroxyl group-containing compound may be one having one or more hydroxyl groups per molecule, preferably one having 1 to 10 hydroxyl groups per molecule, more preferably one having 1 to 4 hydroxyl groups per molecule. preferable.
Further, the molecular weight of the hydroxyl group-containing compound is 1,000 or less, preferably 800 or less, and more preferably 500 or less. The lower limit of the molecular weight of the hydroxyl group-containing compound is not particularly limited, but is preferably 50 or more, and more preferably 80 or more.

Specific examples of the hydroxyl group-containing compound include glycerin, polyglycerin, polyethylene glycol, triethyl citrate, lactic acid, polyvinyl alcohol, propylene glycol, butylene glycol, alcohol, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, and the like. Of these, one or more of them can be used. Glycerin, polyethylene glycol, triethyl citrate, polyglycerin, lactic acid, propylene glycol, and butylene glycol are preferred from the viewpoints of handling properties, slice processability, and safety. Among these, since glycerin has an effect of moisturizing the skin, it is particularly preferable in applications where the glycerin is used by being attached to the skin such as skin care materials and wound dressings.

The content of the hydroxyl group-containing compound in the porous material according to the present invention, that is, the fibroin porous material containing the hydroxyl group-containing compound, needs to be 20 to 75% by mass. The content of the hydroxyl group-containing compound is more preferably 25 to 60% by mass, and further preferably 25 to 45% by mass. When the content of the hydroxyl group-containing compound is within the above range, a porous material excellent in flexibility, workability, and handling properties can be obtained. More specifically, if it is 20% by mass or more, it is excellent in flexibility, hardly cracked during drying, does not become brittle, is not easily cracked during slicing, and provides excellent handling properties. On the other hand, when it is 75% by mass or less, it has excellent flexibility, small shrinkage before and after lyophilization, good surface tack of the porous material, hardly wraps around the roll during slicing, and has excellent handling properties. It is done.
Moreover, the hardness of the porous material of the present invention can be adjusted by changing the content within the above range. As the content of the hydroxyl group-containing compound is increased, the porous material becomes more flexible.

Examples of the fibroin used as a raw material for the fibroin porous material include silkworms, silk fibroin produced from natural silkworms such as rabbits, wild silkworms and tempura, and transgenic silkworms. In the present invention, silk fibroin is preferably used as a raw material from the viewpoint of obtaining a porous material and a porous sheet that are soft even in a dry state and excellent in appearance after drying and slice processability.

Hereinafter, a silk fibroin preferable as a fibroin will be described as an example. The silk fibroin porous material can be obtained from a silk fibroin solution, but when dissolved in water, silk fibroin has poor solubility in water and is difficult to dissolve directly in water. As a method for obtaining a silk fibroin aqueous solution, any known method may be used, but a method in which silk fibroin is dissolved in a high concentration lithium bromide aqueous solution and desalted by dialysis to obtain a silk fibroin aqueous solution is preferable. It is done. Further, as a method for adjusting the concentration of silk fibroin in an aqueous solution, a method through concentration by air drying is simple and preferable.
The method for producing the silk fibroin porous material is not limited, but, for example, a method of obtaining a silk fibroin aqueous solution by rapidly freezing a silk fibroin aqueous solution and then immersing it in a crystallization solvent and simultaneously proceeding with melting and crystallization (Patent Document 1), A method for producing a porous material by freezing a silk fibroin aqueous solution for a long time (Patent Document 2), and adding a small amount of a water-soluble liquid organic substance to a silk fibroin aqueous solution, and then freezing for a certain time. And a technique for obtaining a porous body by melting the composition (Patent Document 3).

The silk fibroin porous material is preferably produced by adding a specific additive to a silk fibroin aqueous solution, freezing the aqueous solution, and then thawing it.
In the production of a silk fibroin porous body, the concentration of silk fibroin is preferably 10 to 400 g / L, more preferably 15 to 200 g / L, and more preferably 20 to 120 g / L in the silk fibroin solution. More preferably. By setting within this range, a silk fibroin porous body having sufficient strength can be efficiently produced.

Preferred examples of the additive include carboxylic acids, amino acids, and water-soluble liquid organic substances. The carboxylic acids used in the production of the silk fibroin porous material preferably have a pKa of 5.0 or less, more preferably 3.0 to 5.0, and more preferably 3.5 to 5.0. More preferred.

The carboxylic acids are not particularly limited as long as they are organic acids having at least one carboxy group in the molecule, and examples thereof include monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids. As the carboxylic acids, carboxylic acids are preferable, aliphatic carboxylic acids having 1 to 6 carbon atoms are more preferable, and aliphatic carboxylic acids having 2 to 5 carbon atoms are more preferable. These aliphatic carboxylic acids may be saturated or unsaturated. Specific examples of such carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, acrylic acid, and 2-butenoic acid; oxalic acid, malonic acid, succinic acid, maleic acid, and the like. Of these, dicarboxylic acids are preferred. These can be used alone or in combination of two or more. In view of safety to the human body, acetic acid, lactic acid, and succinic acid are more preferable.

The amino acid is not particularly limited, and examples thereof include monoaminocarboxylic acids such as valine, leucine, isoleucine, glycine, alanine, serine, threonine, and methionine, and monoaminodicarboxylic acids (acidic amino acids) such as aspartic acid and glutamic acid. Preferred examples include aliphatic amino acids, aromatic amino acids such as phenylalanine, and amino acids having a heterocyclic ring such as hydroxyproline, among which acidic amino acids and oxyamino acids such as hydroxyproline, serine, and threonine are preferred from the viewpoint of easy shape adjustment. preferable. From the same viewpoint, monoaminocarboxylic acid is more preferable among acidic amino acids, aspartic acid and glutamic acid are particularly preferable, and hydroxyproline is more preferable among oxyamino acids. These amino acids can be used alone or in combination of two or more.
Amino acids include L-type and D-type optical isomers, but when L-type and D-type are used, there is no difference in the resulting porous material. good.

The water-soluble liquid organic substance is liquid at room temperature (20 ° C.) and dissolves or mixes without separation when mixed with water at room temperature (20 ° C.). Examples of water-soluble liquid organic substances include alcohols such as methanol, ethanol, isopropanol, and butanol; polyhydric alcohols such as glycerin and propylene glycol; dimethyl sulfoxide (DMSO), dimethylformamide (DMF), pyridine, acetone, acetonitrile, and the like. Is preferred. These can be used alone or in combination of two or more. In consideration of safety to the human body, ethanol, dimethyl sulfoxide, glycerin, and acetone are preferable, and ethanol and glycerin are more preferable.

When the additive is used in the silk fibroin aqueous solution, the content of the additive is preferably 0.1 to 18% by volume, more preferably 0.1 to 5.0% by volume, More preferably, it is 4.0 volume%. By setting within this range, a porous body having sufficient strength can be produced.
The content of amino acid is preferably 1 to 500% by mass, more preferably 5 to 50% by mass, and still more preferably 10 to 30% by mass with respect to silk fibroin.

The freezing of the silk fibroin aqueous solution is preferably performed by pouring a solution obtained by adding an additive to the silk fibroin aqueous solution into a container and placing the container in a liquid-cooled low-temperature thermostat.
The freezing temperature is not particularly limited as long as the silk fibroin aqueous solution added with the additive is frozen, but is preferably about −5 to −40 ° C., more preferably about −10 to −30 ° C., and −15 to More preferably, -25 ° C. The freezing time is preferably 2 hours or longer, and more preferably 4 hours or longer so that the silk fibroin aqueous solution to which the additive is added can be sufficiently frozen and kept frozen. In particular, it is preferable to freeze by holding for 1 to 100 hours under a temperature condition of −15 to −25 ° C.

Here, the silk fibroin aqueous solution to which the additive has been added may be frozen at once to the freezing temperature. However, it is necessary to pass a supercooled state before freezing to obtain a silk fibroin porous body having a uniform structure. preferable. For example, a silk fibroin porous body having a uniform structure can be obtained by temporarily holding an aqueous silk fibroin solution to which an additive has been added at about −5 ° C. for about 2 hours, and then freezing it to a freezing temperature. it can. The structure and strength of the porous body can be controlled to some extent by adjusting the time taken from −5 ° C. to the freezing temperature.

The silk fibroin porous material is obtained by freezing the silk fibroin aqueous solution by the above method and then melting the frozen water. The melting method is not particularly limited, and preferred methods include natural melting and storage in a thermostatic bath.

The silk fibroin porous material thus obtained contains an additive, and when it is necessary to remove the additive depending on the application, the additive is removed from the silk fibroin porous material by an appropriate method. Can be used. For example, the simplest method is to remove the additive by immersing the silk fibroin porous material in pure water.

The silk fibroin porous body has a sponge-like porous structure. Normally, this silk fibroin porous body contains water unless it is removed by freeze-drying or the like. is there. In addition, a dried silk fibroin porous material can be obtained by freeze-drying the silk fibroin porous material. In freeze-drying, when the drying is completed without completely sublimating the water, the pores are crushed due to the effect of the surface tension of the remaining water. Therefore, it is preferable to dry until the water is completely sublimated. For example, the temperature condition is preferably about −5 to −80 ° C.

The silk fibroin porous material can be formed into a shape suitable for the purpose, such as a film shape, a sheet shape, a block shape, a tubular shape, a spherical shape, etc., by appropriately selecting a container for producing the silk fibroin porous material.
The container is not limited as long as the silk fibroin solution has a shape and shape that does not flow out, and as the material, a material having high thermal conductivity such as iron, stainless steel, aluminum, gold, silver, copper, or the like is used. From the viewpoint of reducing the process time required for freezing. Further, the thickness of the mold and the wall of the container is preferably 0.5 mm or more from the viewpoint of its function and deformation due to expansion during freezing, etc., and is easy to handle and efficient in cooling Therefore, the thickness is more preferably 1 to 3 mm.

The mold and container used here can be provided with a release layer on the inner wall surface in contact with the silk fibroin solution inside for the purpose of preventing the silk fibroin porous body from sticking.
As the release layer, a sheet made of a fluororesin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), Alternatively, a release-treated sheet made of polyethylene terephthalate (PET), polypropylene (PP), or the like, or a coating layer made of the above fluororesin is preferable. When these release layers are used, a smooth film layer with few pores is formed on the surface of the silk fibroin porous body. When it is not desired to provide a film layer, most of the film layer can be peeled off by using a sheet having a rough surface such as filter paper. Regarding the use of the release layer, for example, in the cosmetics and esthetics applications, in the case of using a cosmetic component that easily volatilizes, an attempt is made to obtain a longer-lasting cosmetic component effect by suppressing the volatilization of the cosmetic component. When it does, since it is preferable to have a film layer, it is preferable to employ | adopt. Thus, what is necessary is just to select a mold release layer suitably according to the necessity of a film layer.
Further, the thickness of the release layer is preferably 1000 μm or less, more preferably 500 μm or less, and further preferably 200 μm or less. When the thickness of the release layer is within the above range, it is difficult to inhibit heat conduction, and therefore the process time required for freezing can be shortened.

This silk fibroin porous material may be subjected to a cutting process or a cutting process after the melting step described above. When making a silk fibroin porous body into a sheet shape, when making a porous body consisting only of a porous layer, in addition to selecting the material of the container, the surface structure is selected by cutting the film layer be able to. Specifically, for example, a block-shaped mold or container in which a release layer such as a Teflon (registered trademark) sheet is provided on the inner wall surface is taken out from the mold or container, and then the four side film layers are formed. The porous body which consists only of a porous layer can be obtained by removing and cutting or excising the part of a porous layer. Also, a porous body having a film layer only on one side using a mold or a container provided with a release layer such as a Teflon (registered trademark) sheet on the inner wall only on one side and a filter paper on the inner wall on the other side You can also get

The method of incorporating the hydroxyl group-containing compound into the silk fibroin porous material is not particularly limited. When producing the silk fibroin porous material, the method of blending it into the silk fibroin solution or the production of the silk fibroin porous material, It may be a method of immersing in a solution containing a hydroxyl group-containing compound to such an extent as to immerse.

The content of the hydroxyl group-containing compound in the solution containing the hydroxyl group-containing compound is not particularly limited and is, for example, preferably 0.5 to 20% by volume, more preferably 1 to 10% by volume. When the content is within the above range, the hydroxyl group-containing compound is sufficiently introduced into the silk fibroin porous body, and a fibroin porous body containing a hydroxyl group-containing compound suitable for drying is obtained.

The immersion time is not particularly limited, but may be any time as long as the concentration of the hydroxyl group-containing compound in the silk fibroin fibroin porous body becomes uniform. For example, it is preferably 1 to 48 hours, and preferably 12 to 36 hours. Is more preferable. When the immersion time is within the above range, the hydroxyl-containing compound is sufficiently introduced into the silk fibroin porous material, and there is no variation in concentration in the silk fibroin porous material, and the hydroxyl-containing compound is uniformly contained. In addition, a homogeneous porous material can be obtained.

In the porous material of the present invention thus obtained, the hydroxyl group-containing compound is contained in the pores of the silk fibroin porous body constituting the porous material and the porous body so as to constitute the porous body itself. By existing in the structure, a plasticizing effect, a moisturizing effect, and a water absorbing property are exhibited. Since it is such a structure, it is thought that the porous material of the present invention is soft even in a dry state and has excellent appearance after drying and slicing workability.

The porous sheet according to the present invention is made of the above porous material, and the film thickness thereof is 0.1 to 50 mm, preferably 0.2 to 10 mm, more preferably 0.5 to 5 mm. preferable.
The porous sheet can be easily produced by slicing the porous material.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
(Preparation of silk fibroin solution)
Silk fibroin aqueous solution is prepared by dissolving silk fibroin powder (“Silk Powder IM (trade name)”, KB Selen Co., Ltd.) in 9M lithium bromide aqueous solution, removing insoluble matter by centrifugation, and then adding ultrapure water. It was obtained by repeating dialysis against. The obtained silk fibroin aqueous solution was air-dried in a dialysis tube and concentrated. Acetic acid was added as an additive to the concentrated solution to prepare a silk fibroin solution having a silk fibroin concentration of 30 g / L and an acetic acid concentration of 2% by volume.

(Manufacture of silk fibroin porous material)
The silk fibroin solution was poured into a mold (inside size: 400 mm × 300 mm × 20 mm, 60 mm × 30 mm × 10 mm, 100 mm × 10 mm × 10 mm) made of an aluminum plate, and cooled at −5 ° C. in advance. It was placed in a thermostatic bath (manufactured by Maekawa Seisakusho) and allowed to stand at -5 ° C. for 2 hours. As the refrigerant, “Nibline Z1 (trade name)” (manufactured by Maruzen Petrochemical Co., Ltd.) was used.
Thereafter, it was cooled to −20 ° C. at a rate of −3 ° C./hour, and kept at that temperature for 5 hours to freeze. The frozen sample was returned to room temperature by natural thawing, then removed from the mold, immersed in ultrapure water, and the acetic acid used was removed by exchanging the ultrapure water twice a day for 3 days. Thereafter, the silk fibroin porous material prepared by freeze-drying for 3 days using a freeze dryer (“FD-550P (model number)”, manufactured by Tokyo Rika Machinery Co., Ltd.) and having a diameter of 60 mm × 30 mm × 10 mm was dried. The mass was measured.

(Introduction of hydroxyl-containing compound)
A 5% by volume glycerin aqueous solution was prepared so that the entire silk fibroin porous material produced as described above was immersed, and was immersed for 24 hours, and then lyophilized to obtain a porous material. . Further, the dry mass of the porous material after lyophilization was measured.
The content (% by mass) of the hydroxyl group-containing compound in the porous material is obtained by dividing the mass of the hydroxyl group-containing compound introduced into the porous material by the dry mass of the porous material after the hydroxyl group-containing compound is introduced. And calculated by the following formula.
(Content of hydroxyl group-containing compound in porous material (% by mass)) = ((Dry mass of porous material after introduction of hydroxyl group compound) − (Dry mass of silk fibroin porous material into which hydroxyl group-containing compound has not been introduced) ) / (Dry mass of silk fibroin porous material after introduction of hydroxyl group-containing compound) × 100

About the porous material obtained by making it above, the external appearance after drying and slicing workability were evaluated as shown below. The evaluation results are shown in Table 1.
(Appearance after drying)
The appearance of the porous material after drying was observed, and the presence or absence of cracks and the state of the appearance to the extent that they could be visually recognized (width 0.3 mm or more, length 2 mm or more) were evaluated. If the number of cracks is even one, it will be judged as “X”. If there are no cracks but there are appearance abnormalities such as precipitates in the porous material, it will be judged as “△”. did.
(Slicing workability)
The porous material after drying was sliced using a slicing device (manufactured by Kitajima Machine Knife) so that the thickness after slicing was about 1 mm. The case where the sheet or the porous body was broken at the time of slicing was determined as “x”, and the case where there was no crack was determined as “◯”.
(Winding property)
The porous material after drying was sliced using a slicing device (manufactured by Kitajima Machine Knife) so that the thickness after slicing was about 1 mm. Slice 3 times, and when the sheet is wound around the roll 3 times during slicing, “X” means that the sheet is wound once or twice, “△” means that the sheet has not been wound once, “○” It was determined.

Examples 2 to 27 and Comparative Examples 1 to 6
In Example 1, the porous material was the same as in Example 1 except that the type of the hydroxyl group-containing compound and the content of the hydroxyl group-containing compound in the porous material were changed to those shown in Tables 1 to 4. Obtained material. Tables 1 to 4 also show the evaluation results of appearance after drying, slicing workability, and winding property.

From the results of Examples 1 to 27, the porous material of the present invention in which the silk fibroin porous material contains a hydroxyl group-containing compound having a molecular weight of 1,000 or less is excellent in appearance after drying and slice processability. Was confirmed. On the other hand, from the results of Comparative Examples 1 to 7, a compound containing no hydroxyl group, or a material containing a compound containing a hydroxyl group but having a molecular weight higher than 1,000 has cracks after drying, abnormal appearance, It was confirmed that cracking occurred during slicing.

Examples 28-35 and Comparative Examples 7 and 8
In Example 1, the raw material of the silk fibroin aqueous solution was made from silk fibroin powder scoured slag (manufactured by Nagasuna Coffee Co., Ltd.), the silk fibroin aqueous solution had a silk fibroin concentration of 40 g / L, and the hydroxyl group-containing compound solution The porous material was prepared in the same manner as in Example 1 except that the concentration of the compound in the inside was changed to that shown in Table 5, and the size of the mold made of an aluminum plate was changed to that having an inner diameter of 400 mm × 300 mm × 20 mm. Obtained. Table 5 also shows the evaluation results of appearance after drying, slicing workability, and winding property.

* 1, GLy: glycerin PEG: polyethylene glycol PGL: polyglycerin TEC: triethyl citrate DGL: decaglycerin laurate SL: sorbitan laurate DMSO: dimethyl sulfoxide PVA: polyvinyl alcohol DOP: dioctyl phthalate OIL: epoxidized soybean oil * 2, v: volume%, w: mass%

Further, for the porous materials obtained in Examples 28, 30 to 32 and Comparative Example 1, 25% compressive stress was measured based on the following method. The compressive stress of the porous material of Example 28 is 80.1 kPa, the compressive stress of the porous material of Example 30 is 55.1 kPa, and the compressive stress of the porous material of Example 31 is 46.8 kPa. The compressive stress of the porous material of Example 32 was 43.1 kPa. On the other hand, the compressive stress of the porous material of Comparative Example 1 was 437.6 kPa, which was almost 10 times larger than the compressive stress of the porous material of the example, and was confirmed to be significantly inferior in flexibility.
Further, from the photographic images of FIGS. 1 to 6, it was confirmed that cracks did not occur in the examples but cracks in the comparative examples.

(Measurement of 25% compressive stress)
For the materials obtained in each of the examples and comparative examples, a universal testing machine (“EZ- (N) S (model number)”, manufactured by Shimadzu Corporation) was used, the load cell was 50 N, and the jig was a circle with a diameter of 8 mm. , The load when 25% of the thickness of the material was pushed by the compression plate under the conditions of a compression speed of 1 mm / min and a room temperature of 22 ° C. was measured, and a value calculated by the following equation was 25 % Compressive stress (kPa).
25% compressive stress (kPa) = Load / compression plate area (mm ² ) × 1000 when 25% of the thickness of the material is pressed with the compression plate

The porous material of the present invention can be widely applied to the cosmetics and esthetic fields, and is extremely useful as a face mask or eye mask adapted to the shape of the face. In addition, medical fields such as wound dressings, sustained drug carriers, hemostatic sponges, daily necessities such as disposable diapers and sanitary products, cell culture supports and tissue regeneration supports in tissue engineering and regenerative medical engineering, water purification applications and environmental fields It can be applied to various industries, such as a support that becomes a place of residence for microorganisms and bacteria.

Claims (4)

A porous material, wherein the fibroin porous material contains 20 to 75% by mass of a hydroxyl group-containing compound having a molecular weight of 1,000 or less. The hydroxyl group-containing compound is selected from glycerin, polyglycerin, polyethylene glycol, triethyl citrate, lactic acid, polyvinyl alcohol, propylene glycol, butylene glycol, alcohol, glycerin fatty acid ester, polyglycerin fatty acid ester, and sorbitan fatty acid ester It is the above, The porous material of Claim 1. The porous material according to claim 1, wherein the hydroxyl group-containing compound is glycerin. A porous sheet made of the porous material according to any one of claims 1 to 3 and having a thickness of 0.1 to 50 mm.

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