JP6295103B2 - Water swellable sheet - Google Patents

Description

  The present invention relates to a water-swellable sheet. More specifically, for example, an organ adhesion-preventing film for preventing adhesion of an organ or the like during surgery, an adhesive bandage for wound treatment, a wound covering film, a cooling sheet, a cushion sheet for organ preservation, a body fluid absorbing sheet, The present invention relates to a water-swellable sheet expected to be used for applications such as a cell culture sheet.

  In the present invention, the water-swellable sheet means a sheet having a property of swelling with water or an aqueous solution in which water is used as a solvent.

  Aqueous gel has attracted attention as a bio-related material because it has water swellability and is flexible. Among aqueous gels, aqueous gels that have the property of swelling while absorbing body fluids have been studied for use as surgical scar adhesion prevention films and films for covering wounds.

  Proposal of a hydrophilic gel sheet obtained by irradiating a liquid film made of linear water-soluble polyethylene oxide with high energy rays as a new aqueous gel sheet that has excellent adhesiveness and biocompatibility and absorbs a large amount of aqueous solution. (For example, refer to Patent Document 1).

  However, since the hydrophilic gel sheet has a low tensile strength, it cannot be said that it is suitable for applications such as a wound dressing film.

  A gel sheet for medical materials obtained by irradiating ionizing radiation to an aqueous solution containing polyethylene oxide and polyvinyl alcohol has been proposed as a gel sheet that eliminates the disadvantages of the hydrophilic gel sheet and has excellent tensile strength ( For example, see Patent Document 2).

  However, in order to apply the gel to a biocompatible material, it is difficult to remove the gel from the living tissue when the gel is applied to the living tissue and then impregnated with the aqueous component. When impregnated, the gel swells in the thickness direction, but is difficult to swell in the in-plane direction, that is, has a swelling anisotropy. When the gel sheet is impregnated with an aqueous component The gel sheet swells at a similar swelling ratio three-dimensionally in the thickness direction and in-plane direction, and is inferior in swelling anisotropy. Therefore, the gel sheet is applied to a biocompatible material requiring swelling anisotropy. I can't say.

  Therefore, in recent years, when it is impregnated with an aqueous component, it swells in the thickness direction, but does not swell in the in-plane direction, has excellent swelling anisotropy, and can be used as a biocompatible material. Development of seats is desired.

JP-A 63-29649 Japanese Patent Laid-Open No. 2000-210375

  The present invention has been made in view of the prior art, and when impregnated with an aqueous component, it swells in the thickness direction, but does not easily swell in the in-plane direction and has excellent swelling anisotropy, for example, Organ adhesion prevention film to prevent adhesion of organs at the time of surgery, bandage for wound treatment, wound covering film, cooling sheet, cushion sheet for organ preservation, body fluid absorption sheet, cell culture sheet, etc. It is an object to provide a water-swellable sheet that is expected to be used for applications.

The present invention
(1) A polysaccharide water swellable sheet comprising a used as a raw material, the polysaccharide is a Aphanothece sacrum polysaccharide having a weight average molecular weight of 4 million to 60 million, the thickness of when swollen with water Water swellable sheet, characterized in that the linear swelling change rate in the direction is 1000% or more and the linear swelling change rate in the in-plane direction is 10% or less,
(2) A raw material as polysaccharide method of producing a water-swellable sheet comprising a used, using Aphanothece sacrum polysaccharide having a weight average molecular weight of 4 million to 60 million as the polysaccharide, the Aphanothece sacrum polysaccharide and Dissolving divinyl sulfone in an aqueous solvent, forming a film using the obtained suizendinori polysaccharide aqueous solution, and drying the formed film in an atmosphere having a temperature of 1 to 60 ° C. over 2 to 300 hours. The method for producing a water-swellable sheet according to (1 ) above, and ( 3 ) a method for producing a water-swellable sheet using a polysaccharide as a raw material, wherein the polysaccharide is 4 million to 6000. using Aphanothece sacrum polysaccharide having a weight average molecular weight of ten thousand, the Aphanothece sacrum polysaccharide dissolved in an aqueous solvent, resulting Aphanothece sacrum polysaccharide A film is formed using an aqueous solution, and the formed film is dried in an atmosphere having an air temperature of 1 to 60 ° C. over 2 to 300 hours, and then further dried to obtain a film obtained by drying at 80 to 160 ° C. heated to the temperature, producing how the water-swellable sheet according to above, wherein the cross-linking the Aphanothece sacrum polysaccharides (1)
About the.

  In addition, in this invention, although a sheet | seat, a film, and a film | membrane (membrane) have a difference in a form, the said sheet | seat includes the concept of a film and a film | membrane (membrane).

  According to the present invention, when impregnated with an aqueous component, it swells in the thickness direction, but does not swell in the in-plane direction and has excellent swelling anisotropy, for example, an organ during surgery adheres. Water expected to be used in applications such as anti-adhesion membranes for wound prevention, bandages for wound treatment, wound-covering membranes, cooling sheets, cushion sheets for organ preservation, body fluid absorption sheets, cell culture sheets, etc. A swellable sheet is provided.

  The water-swellable sheet of the present invention is a water-swellable sheet in which a polysaccharide is used as a raw material, and the polysaccharide is a liquid crystalline polysaccharide having a weight average molecular weight of 4 million to 60 million, and is swollen with water. The linear swelling change rate in the thickness direction (perpendicular to the film surface) is 1000% or more, and the linear swelling change rate in the in-plane direction (horizontal direction with respect to the film surface) is 10% or less. It is characterized by that.

  In the present invention, liquid crystallinity means a property of self-orientation in a solution having a certain concentration or higher dissolved in an aqueous solvent. Therefore, as the solvent is removed from the solution in which the polysaccharide having liquid crystallinity is dissolved in the solvent, the concentration of the polysaccharide increases, and finally, a dry sheet in which the polysaccharide is self-oriented is obtained.

The linear swelling change rate in the thickness direction or in-plane direction is expressed by the formula:
[Linear swelling change rate in thickness direction or in-plane direction (%)]
= {([Thickness in the thickness direction or in-plane direction after swelling] − [Thickness in the thickness direction or in-plane direction before swelling]) ÷ [Thickness in the thickness direction before swelling or in-plane direction] ] × 100
It is a value when calculated based on.

  The present inventors, when impregnated with an aqueous component, swell in the thickness direction, but hardly swell in the in-plane direction, for example, organ adhesion for preventing adhesion of an organ or the like during surgery. It is expected to be used as a water-swellable sheet used in applications such as anti-preventive membranes, wound treatment bandages, wound-covering membranes, cooling sheets, organ preservation cushion sheets, body fluid absorption sheets, and cell culture sheets. As a result of extensive research to develop a water-swellable sheet, liquid crystalline polysaccharides having a weight average molecular weight of 4 million to 60 million among various polysaccharides swell in the thickness direction. It has been found that it is difficult to swell in the direction and can be suitably used to produce a water-swellable sheet having swelling anisotropy.

  Examples of the liquid crystalline polysaccharide having a weight average molecular weight of 4 million to 60 million include, but are not limited to, suizendinori polysaccharide (weight molecular weight: 20 million or more), xanthan gum (weight molecular weight: 4 million), etc. It is not limited only to such illustration. These liquid crystalline polysaccharides may be used alone or in combination of two or more. Among these liquid crystalline polysaccharides, suizendinori polysaccharides are preferable because they swell in the thickness direction but are not easily swelled in the in-plane direction. Suizenjinori polysaccharide can be easily extracted from Suizenjinori.

  The liquid crystalline polysaccharide may be used by mixing with other water-soluble polymer compounds other than the liquid crystalline polysaccharide within the range in which the object of the present invention is not inhibited.

  Examples of polysaccharides include cellulose, amylose, chitin, pectin, fucoidan, carrageenan, alginic acid, konjac, glucomannan, hyaluronic acid, chondroitin, heparin, and spirulan. Since these polysaccharides swell almost equally in the thickness direction and the in-plane direction, it has been confirmed that they cannot be used suitably for water-swellable sheets having swelling anisotropy. .

The water-swellable sheet of the present invention is, for example,
(1) A liquid crystalline polysaccharide having a weight average molecular weight of 4 million to 60 million is used as the polysaccharide, the liquid crystalline polysaccharide and the water-soluble crosslinking agent are dissolved in an aqueous solvent, and the obtained liquid crystalline polysaccharide aqueous solution is obtained. A method of forming a film using the method, and drying the formed film in an atmosphere having an air temperature of 1 to 60 ° C. over 2 to 300 hours (hereinafter referred to as method 1),
(2) Using a liquid crystalline polysaccharide having a weight average molecular weight of 4 million to 60 million as the polysaccharide, dissolving the liquid crystalline polysaccharide in an aqueous solvent, and forming a film using the obtained aqueous liquid crystalline polysaccharide solution The formed film is dried in an atmosphere having an air temperature of 1 to 60 ° C. over 2 to 300 hours, and then the film obtained by further drying is heated to a temperature of 80 to 160 ° C. To crosslink the polysaccharide (hereinafter referred to as Method 2)
It can prepare by.

  In Method 1, the liquid crystalline polysaccharide solution can be prepared by dissolving the liquid crystalline polysaccharide and the water-soluble crosslinking agent in an aqueous solvent. In Method 2, the liquid crystalline polysaccharide solution can be prepared by dissolving the liquid crystalline polysaccharide in an aqueous solvent.

  In Method 1, the concept of dissolving the liquid crystalline polysaccharide and the water-soluble crosslinking agent in the aqueous solvent includes not only dissolving the liquid crystalline polysaccharide and the water-soluble crosslinking agent in the aqueous solvent as worded, but also liquid crystallinity. It includes dissolving a water-soluble crosslinking agent in a solution in which a polysaccharide is dissolved in an aqueous solvent, and dissolving liquid crystalline polysaccharide in a solution in which the water-soluble crosslinking agent is dissolved in an aqueous solvent.

  Examples of the aqueous solvent include water, aliphatic monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol; aliphatic polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin. Ethers such as methyl cellosolve, ethyl cellosolve, tetrahydrofuran, dioxane, diglyme and diethyl ether; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; amides such as formamide, dimethylacetamide, dimethylformamide and N-methylpyrrolidone; Esters: carbonates such as dimethyl sulfoxide and propylene carbonate, carboxylic acids such as acetic acid, and the like. It is not limited. These aqueous solvents may be used alone or in combination of two or more. Of these aqueous solvents, water is preferred. The pH of an aqueous solvent is not specifically limited, Usually, what is necessary is just 1-14.

  The aqueous solvent may contain, for example, an inorganic salt such as sodium chloride dissolved in the range in which the object of the present invention is not impaired.

  The temperature of the aqueous solvent when dissolving the liquid crystalline polysaccharide in the aqueous solvent is not particularly limited, but is preferably about 20 to 95 ° C. from the viewpoint of efficiently dissolving the liquid crystalline polysaccharide in the aqueous solvent. When dissolving the liquid crystalline polysaccharide in the aqueous solvent, it is preferable to dissolve the liquid crystalline polysaccharide in the aqueous solvent under stirring of the aqueous solvent from the viewpoint of sufficiently dissolving the liquid crystalline polysaccharide. The time required for dissolving the liquid crystalline polysaccharide in the aqueous solvent varies depending on the temperature at which the liquid crystalline polysaccharide is dissolved, the amount of the liquid crystalline polysaccharide to be dissolved, etc. From the viewpoint of obtaining a water-swellable sheet that swells in the thickness direction when impregnated with components but does not swell in the in-plane direction, it is preferably 1 to 24 hours, more preferably 2 to 16 hours, still more preferably 4 -10 hours. The aqueous component means water or a liquid containing water, and typical examples thereof include the aqueous solvent and body fluid. However, the present invention is not limited to such examples.

  The concentration of the liquid crystalline polysaccharide in the liquid crystalline polysaccharide solution obtained by dissolving the liquid crystalline polysaccharide in the aqueous solvent swells in the thickness direction when impregnated with the aqueous component, but does not swell in the in-plane direction. From the viewpoint of obtaining a water-swellable sheet having swelling anisotropy, it is preferably 0.01 to 30% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.3 to 3% by mass. .

  In Method 1, the liquid crystalline polysaccharide solution contains a water-soluble crosslinking agent in order to sufficiently gel the liquid crystalline polysaccharide solution.

  The water-soluble cross-linking agent is prepared by preparing a gel in which one or more functional groups of the water-soluble cross-linking agent are introduced in an unreacted state, and drying the obtained gel. Has the property of stabilizing the structure.

  Examples of the water-soluble crosslinking agent include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butanediol di ( (Meth) acrylate compounds having at least 2, preferably 2 to 4, (meth) acryloyl groups such as (meth) acrylate, glycerin di (meth) acrylate, trimethylpropane tri (meth) acrylate; N, N′-methylenebis Bis (meth) acrylamide compounds such as acrylamide; Dialkylene glycol divinyl ether such as divinyl sulfone, divinyl benzene and diethylene glycol divinyl ether; Divinyl ketone; Ethylene glycol diglycol At least 2, preferably 2 epoxy groups such as dil ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, polyglycerin diglycidyl ether, sorbitol polyglycidyl ether Epoxy compounds; halogenated epoxy compounds such as epichlorohydrin, epibromohydrin, α-methylepichlorohydrin; 2,4-tolylene diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate An isocyanate compound having at least 2, preferably 2 isocyanate groups such as lysine methyl diisocyanate; -3-oxetanemethanol, 3-ethyl-3-oxetanemethanol, 3-butyl-3-oxetanemethanol, 3-methyl-3-oxetaneethanol, 3-ethyl-3-oxetaneethanol, 3-butyl-3-oxetaneethanol Oxetane compounds such as: aldehyde compounds such as formaldehyde, glyoxal, malealdehyde, glutaraldehyde; urea; triazine compounds such as N, N, N-triacryloylhexahydrotriazine, N, N, N-triacryloylhexahydrotriazine; ethylenediamine An amine compound having at least 2, preferably 2 or 3, amino groups such as propylenediamine, paraphenylenediamine, lysine methyl ester, polyamidoamine dendrimer, polylysine; Examples thereof include carboxylic acid compounds having at least 2, preferably 2 or 3, carboxyl groups such as ronic acid, succinic acid, adipic acid, sebacic acid, itaconic acid, terephthalic acid, fumaric acid, maleic acid and polyacrylic acid. However, the present invention is not limited to such examples. These water-soluble crosslinking agents may be used alone or in combination of two or more.

  Among water-soluble crosslinking agents, (meth) acrylate compounds, bis (meth) acrylamide compounds, divinylbenzene, divinylsulfone, diethylene glycol divinyl ether, divinyl ketone having at least two (meth) acryloyl groups, preferably 2 to 4 , Epoxy compounds having at least 2, preferably 2 epoxy groups, isocyanate compounds having at least 2, preferably 2 isocyanate groups, oxetane compounds, aldehyde compounds, urea, triazine compounds, at least 2 amino groups, preferably Is preferably an amine compound having 2 or 3 and a carboxylic acid compound having at least 2, preferably 2 or 3, carboxyl groups, and having at least 2, (preferably 2 to 4) (meth) acryloyl groups. (Meth) acrylate compound, bis (meth) acrylamide compound, at least two of divinyl sulfone and isocyanate groups, preferably is more preferably an isocyanate compound having two, divinyl sulfone are more preferred. These water-soluble crosslinking agents may be used alone or in combination of two or more.

  The water-soluble crosslinking agent may be mixed with an aqueous solvent, or may be mixed with a liquid crystalline polysaccharide solution.

  In the present invention, (meth) acryloyl means acryloyl or methacryloyl, (meth) acrylate means acrylate or methacrylate, and (meth) acrylamide means acrylamide or methacrylamide.

  The amount of water-soluble crosslinking agent varies depending on the type of liquid crystalline polysaccharide and cannot be determined unconditionally, but normally it swells in the thickness direction when it is impregnated with an aqueous component, but it swells in the in-plane direction. From the viewpoint of obtaining a difficult water-swellable sheet, it is preferably 0.3 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, and still more preferably 0.5 to 1 per 100 parts by mass of the liquid crystalline polysaccharide. Part by mass.

  Next, in Method 1, a film is formed by applying a liquid crystalline polysaccharide solution in which a liquid crystalline polysaccharide and a water-soluble crosslinking agent are dissolved to a substrate. In Method 2, a film is formed by applying a liquid crystalline polysaccharide solution in which a liquid crystalline polysaccharide is dissolved in an aqueous solvent to a substrate.

  Hereinafter, unless otherwise specified, a liquid crystal polysaccharide solution in which a liquid crystal polysaccharide and a water-soluble crosslinking agent are dissolved, and a liquid crystal polysaccharide solution in which a liquid crystal polysaccharide is dissolved in an aqueous solvent, Is also called a liquid crystalline polysaccharide solution.

  Examples of the base material used when the liquid crystalline polysaccharide solution is applied to the base material include glass plates, polyolefins such as polypropylene and polyethylene; polyesters such as polyethylene terephthalate; polyamides typified by nylon 66 and the like; ) Resin plate made of resin such as acrylic resin typified by acrylate, fiber reinforced resin (FRP) plate, carbon plate, various metal plates, etc. are mentioned, but the present invention is not limited to such illustration only. Absent.

  Examples of the method for applying the liquid crystalline polysaccharide solution to the substrate include spray coating, roll coating, brush coating, gravure coating, reverse coating, roll brushing, air knife coating, dipping (dipping). However, the present invention is not limited to such examples.

  The thickness of the film formed by applying the liquid crystalline polysaccharide solution to the substrate is not particularly limited, but it has excellent tensile strength, improves the swelling property in the thickness direction of the film, and improves the swelling anisotropy. From the viewpoint of improving the coatability, the thickness is preferably 30 to 300 μm, more preferably 50 to 200 μm. In addition, after drying the formed film, the thickness of the film can be increased by further applying a liquid crystalline polysaccharide solution on the film.

  Next, the film formed by applying the liquid crystalline polysaccharide solution to the substrate as described above is dried.

  In the present invention, there is another major feature in a method of forming a film by applying a liquid crystalline polysaccharide solution to a substrate and drying the formed film over time.

  In general, as a method for drying a formed film, a heat drying method, a warm air drying method, a drying method by irradiation with an electron beam such as infrared rays, and the like are known. On the other hand, in the method (1) and the method (2) in the present invention, unlike these drying methods, a method of actively drying without heating to a high temperature is adopted. Although it swells in the vertical direction, it is difficult to swell in the in-plane direction, and a water-swellable sheet excellent in swelling anisotropy can be obtained.

  The reason why the water-swellable sheet of the present invention has such an excellent property is not certain, but probably when the liquid crystalline polysaccharide solution is dried, the liquid crystallinity is gradually decreased as the thickness of the film is gradually decreased. Since the polysaccharide molecules are gradually oriented in the in-plane direction and a water-soluble crosslinking agent is used in the method (1), when the liquid crystalline polysaccharide solution is dried, The liquid crystal polysaccharide is cross-linked and the formed cross-linked structure is stabilized by drying. In the method (2), the liquid crystal polysaccharide solution is dried to align the molecules of the liquid crystal polysaccharide in the in-plane direction. Since the coating film is further heated, it is considered that the liquid crystalline polysaccharide is crosslinked by the heating, and the formed crosslinked structure is stabilized.

  Among the methods (1) and (2), the method (1) does not need to heat the dry film formed as in the method (2), and the water swelling has excellent swelling anisotropy. The method (2) is preferable because the water-soluble crosslinking agent is not used as in the method (1), and is excellent in biocompatibility.

  The film formed of the liquid crystalline polysaccharide solution can be dried in an atmosphere such as air having an air temperature of 1 to 60 ° C., preferably 5 to 50 ° C. In that case, you may ventilate in the range which does not inhibit the objective of this invention as needed. Moreover, there is no limitation in particular also about the relative humidity of the atmosphere when drying the formed film, What is necessary is just about normal relative humidity, for example, about 30 to 80%.

  The time required for drying a film formed by applying a liquid crystalline polysaccharide solution containing a water-soluble crosslinking agent to a substrate swells in the thickness direction, but hardly swells in the in-plane direction. From the viewpoint of obtaining a water-swellable sheet excellent in swelling anisotropy, it is preferably 10 to 300 hours, more preferably 80 to 250 hours, and further preferably 120 to 200 hours.

  According to the method (1), the water-swellable sheet of the present invention is obtained by performing the above operation. The obtained water-swellable sheet can be used for use by peeling from the substrate.

  In the method (2), since a water-soluble crosslinking agent is not used, after the film formed by applying the liquid crystalline polysaccharide solution to the substrate is dried, the resulting dried film is 80 Heat at a temperature of ~ 160 ° C.

  In Method 2, the dried film can be heated using, for example, a thermostatic bath, a thermostatic chamber, a hot air dryer, etc., and the present invention is not limited by the heating means. The heating temperature of the dry film is 80 to 160 ° C., preferably 100 to 160 ° C., more preferably 120 to 140 ° C. from the viewpoint of sufficiently crosslinking the dry film and leaving no thermal history in the dry film. It is. In addition, the drying time varies depending on the drying temperature and cannot be determined in general. However, the drying time is a time required to generate a physical interaction such as a hydrogen bond in the dry film, and usually 30 minutes to 10 days. Preferably, it is 1 hour to 7 days. In addition, you may perform a heating of a dry film, after peeling a dry film from a base material.

  In Method 2, the water-swellable sheet of the present invention is obtained by heating the dry film as described above. The obtained water-swellable sheet can be used for use by peeling from the substrate.

  The thickness of the water-swellable sheet of the present invention after drying is the thickness of a film formed by applying a liquid crystalline polysaccharide solution containing a water-soluble crosslinking agent to a substrate, and the liquid crystal in the liquid crystalline polysaccharide solution. Since it differs depending on the concentration of the polysaccharide, etc., it cannot be determined unconditionally, but it is usually about 10 to 100 μm.

  In addition, the magnitude | size of the water-swellable sheet of this invention is arbitrary, and it is preferable to adjust suitably according to the use of the water-swellable sheet of this invention.

  The water-swellable sheet of the present invention obtained as described above swells in the thickness direction but is difficult to swell in the in-plane direction, in other words, has excellent swelling anisotropy.

  The swelling anisotropy of the water-swellable sheet can be evaluated by the linear swelling change rate of the water-swellable sheet. The linear swelling change rate of the water-swellable sheet is determined by the length of the in-plane direction and the thickness direction of the water-swellable sheet in the dry state, and water-based characteristics represented by water until there is almost no dimensional change. The length and thickness in the in-plane direction of the water-swellable sheet after swelling with the solvent are measured, and the length and thickness in the in-plane direction of the water-swellable sheet after swelling in the aqueous solvent are measured. The difference between the length in the longitudinal direction and the length in the in-plane direction and the length in the thickness direction of the water-swellable sheet in the dry state is the length in the in-plane direction and the length in the thickness direction of the water-swellable sheet in the dry state, respectively. It can be obtained by dividing by this and multiplying the value obtained by 100.

  The larger the linear swelling change rate in the thickness direction of the water-swellable sheet, the better. The linear swelling change rate in the thickness direction of the water-swellable sheet is, for example, an organ adhesion-preventing film, an adhesive bandage for wound treatment, a wound covering film, or a cooling sheet for preventing an organ or the like from adhering during surgery. From the viewpoint of increasing the swelling anisotropy so that it can be suitably used for applications such as a cushion sheet for organ preservation, a body fluid absorbing sheet, and a cell culture sheet, it is 1000% or more, preferably 1500% or more. Although the upper limit is not particularly limited, it is usually preferably 100,000% or less, more preferably 50000% or less.

  The linear swelling change rate in the in-plane direction of the water-swellable sheet is preferably small. The linear swelling change rate in the in-plane direction of the water-swellable sheet is, for example, an organ adhesion-preventing film, an adhesive bandage for wound treatment, a wound covering film, or a cooling sheet for preventing an organ or the like from adhering during surgery. From the viewpoint of increasing the swelling anisotropy so that it can be suitably used for applications such as a cushion sheet for organ preservation, a body fluid absorbing sheet, and a cell culture sheet, 10% or less, preferably 8% or less, More preferably, it is 5% or less, and the lower limit is not particularly limited, but is usually 0%.

Further, the ratio of the linear swelling change rate of the water-swellable sheet of the present invention is that when it is impregnated with an aqueous component, it swells in the thickness direction but does not swell in the in-plane direction and has excellent swelling anisotropy From the viewpoint of obtaining a swellable sheet, it is preferably 100 or more, more preferably 500 or more, and still more preferably 2000 or more. Linear swelling rate of change ratio of the water-swellable sheet plane direction of the length of the water-swellable sheet (a ₀₎ and the thickness direction of the length of (b ₀₎ is measured, the dimensional change of the water-swellable sheet plane direction of length of the water-swellable sheet after being swollen with an aqueous solvent typified by water until no (a ₁₎ and the thickness direction of the length (b ₁₎ were measured, the formula (I) :
[Swelling change rate ratio]
= {[((B ₁ −b ₀ ) ÷ b ₀ ] ÷ [(a ₁ −a ₀ ) ÷ a ₀ ]} (I)
Is a value obtained according to

  The water-swellable sheet of the present invention swells in the thickness direction because the linear swelling change rate ratio obtained based on the formula (I) is preferably 100 or more, more preferably 500 or more, and still more preferably 2000 or more. However, since it has an excellent property that it is difficult to swell in the in-plane direction, for example, an organ adhesion-preventing film, an adhesive bandage for wound treatment, and a wound covering film for preventing an organ or the like from adhering at the time of surgery It is expected to be used as a water-swellable sheet used for applications such as a cooling sheet, a cushion sheet for organ preservation, a body fluid absorbing sheet, and a cell culture sheet. The upper limit of the linear swelling change ratio of the water-swellable sheet of the present invention is preferably as large as possible, and is not particularly limited. However, from the viewpoint of improving shape stability, it is preferably 200000 or less, more preferably 150,000 or less, and further Preferably it is 120,000 or less.

  Since the water-swellable sheet of the present invention is excellent in swelling anisotropy, for example, in order to prevent adhesion between organs during surgery of animals such as humans, it is desired to prevent adhesion of the organs Can be inserted in between. As described above, when the water-swellable sheet of the present invention is inserted between organs, the water-swellable sheet is swollen by body fluid, so that adhesion between organs can be prevented. Further, the water-swellable sheet of the present invention uses a liquid crystalline polysaccharide excellent in human compatibility, preferably a suizendinori polysaccharide and / or xanthan gum, more preferably a suizendinori polysaccharide, and it decomposes with time. Therefore, even if a water-swellable sheet is inserted into the body at the time of surgery, it will not cause any trouble.

  Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Production Example After freezing the original sample of Aphanothece sacrum, thawing the scorpion cell body by thawing, eluting the phycobiliprotein, which is a fluorescent dye contained in the suizeninori cell body, It was removed by washing with water.

  Next, the water-washed lichenzinori original sample washed with water was washed with isopropanol to remove fat-soluble dyes, chlorophyll, carotenoid-based dyes, and the like contained in the suisuzinori original sample. The suizendinori cell body washed with isopropanol as described above is immersed in an aqueous 0.1N sodium hydroxide solution and stirred for 5 hours while maintaining the solution temperature at 80 ° C., thereby completely destroying the suizendinori cell body. In addition, biopolymers such as proteins and DNA contained in the suizendinori sample were decomposed to obtain a solution containing these destruction residue, degrading residue and suizendinori polysaccharide.

  The solution obtained above was filtered with gauze to remove impurities, and then neutralized with hydrochloric acid until the pH of the solution reached about 7-8. Thereafter, a mixed solvent of isopropanol and water (volume ratio of isopropanol and water: 70:30) was added to this solution and stirred to purify and recover the suizendinori polysaccharide.

  The suizendinori polysaccharide recovered in the above was dissolved again in water, and the resulting suizendinori polysaccharide aqueous solution was added to isopropyl alcohol to dehydrate and fibrillate it. The yield of the fiberized Suizendinori polysaccharide was about 50 to 80% by mass based on the dry weight of the Suizendinori original sample.

  The weight average molecular weight of the Suizendinori polysaccharide purified as described above was measured by the multi-angle static light scattering method (MALLS) under the following measurement conditions. As a result, it was confirmed that the weight average molecular weight of the Suizendinori polysaccharide was 29 million. The purified Suizendinori polysaccharide was used in the following examples.

〔Measurement condition〕
・ Equipment: Wyatt Technology, product name: Dawn Heleos II
・ Concentration at injection: 0.01% by mass
・ Injection volume: 100 μL
・ Flow rate: 1 mL / min
-Solvent: 0.1M sodium nitrate aqueous solution-Column: Showa Denko K.K., trade name: Shodex OHpak SB-807 HQ and trade name: Shodex OHpak SB-804 HQ
Column temperature: 40 ° C
・ Measurement temperature: 25 ℃
・ Laser wavelength: 665.2 nm
Measurement angle: 13.0 °, 20.7 °, 29.6 °, 37.5 °, 44.8 °, 53.1 °, 61.1 °
Cell type: fused silica RI detector: manufactured by Wyatt Technology, trade name: Optilab T-rEX, laser wavelength: 658.0 nm

Example 1
Aqueous solution containing 0.2M sodium hydroxide and containing a suizendinori polysaccharide [average sugar residue molar mass: 180 g / mol, average mass: 160 mg (0.89 mmol)] at a concentration of 0.8 mass / volume%. By adding 118 mg (100 μL, 1 mmol, molecular weight: 118) of divinyl sulfone as a water-soluble crosslinking agent to 20 mL, a liquid crystalline polysaccharide solution containing divinyl sulfone was obtained. The liquid crystalline polysaccharide solution obtained above was spray-coated on a polyester plate having a flat surface. The plate was allowed to stand in the atmosphere at 25 ° C. for 170 hours to dry the film, thereby obtaining a water-swellable sheet. When the obtained water-swellable sheet was peeled off from the plate and the thickness thereof was measured, the thickness was about 20 μm.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days to wash out the unreacted crosslinking agent into water, the water-swellable sheet is taken out from the water and visually observed. As a result, it was confirmed that the film was hardly swollen in the in-plane direction and was greatly swollen in the thickness direction. Therefore, when the rate of linear swelling change in the thickness direction and the rate of linear swelling change in the in-plane direction of the water-swellable sheet swollen with water were investigated, the line in the thickness direction of the water-swellable sheet obtained above was examined. The swelling change rate was 6650%, and the linear swelling change rate in the in-plane direction was confirmed to be 0.15%.

  Next, when the linear swelling change ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change ratio was 43400. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  Next, a square test piece having a side length of 10 mm was cut out from the water-swellable sheet obtained above, and the physical properties of the water-swellable sheet were obtained using the obtained test piece. Investigated based on the method. As a result, it was confirmed that the compression elastic modulus in the water-swollen state was 231 kPa.

[Method of measuring compression modulus]
The compressive elastic modulus of the water-swellable sheet was measured using a Tensilon universal material tester (manufactured by A & D Co., Ltd., trade name: Instron 3365, load cell: 5 kN) at a compression rate of 1 mm / min and a temperature of 25 ° C. It was measured.

  Moreover, when the water-swellable sheet obtained above was dried again and elemental analysis of the water-swellable sheet was performed, the carbon atom was 35.67% by mass, the hydrogen atom was 5.53% by mass, and the nitrogen atom was 0.60. It was found that 5% by mass and 5.11% by mass of sulfur atoms were contained. Based on these results, the introduction rate of divinylsulfone as a crosslinking agent into the water-swellable sheet was determined, and it was found that the introduction rate of divinylsulfone per saccharide residue of the suizendinori polysaccharide was 8.4 mol%. confirmed.

  From the above results, it can be seen that the divinyl sulfone reacted with the suizendinori polysaccharide at a reaction rate of about 7/100, compared with the ratio (112 mol%) of the suizendinori polysaccharide to the sugar residue when the divinylsulfone was charged. From this, it can be seen that divinyl sulfone has extremely low reactivity with respect to the sugar residue of the suizendinori polysaccharide.

The degree of swelling (q) per dry weight of the water-swellable sheet obtained above is expressed by the formula:
[Swelling degree per dry weight of water-swellable sheet (q)]
= [Weight of the sheet after swelling] ÷ [weight of the dried sheet before swelling]
The degree of swelling (q) is 21, and the molecular weight between crosslinks (Mc) is expressed by the formula:
[Molecular weight between cross-linking points (Mc)] = 3 (d / q) RT / K
[Wherein, d is the density (1 g / cm ³ ) of the water-swellable sheet, q is the degree of swelling per dry weight of the water-swellable sheet, R is the gas constant, and T is the temperature (300K)]
The molecular weight (Mc) between crosslinking points was 1500 g / mol.

Further, the crosslinking density of the water-swellable sheet obtained above is expressed by the formula:
[Crosslinking density] = [Average molecular weight of sugar residues of Suizendinori polysaccharide] / 2 [Molecular weight between crosslinking points]
The crosslink density was 6 mol% when determined based on the above formula.

  Since the crosslink density of the swellable sheet was slightly lower than the introduction rate of divinylsulfone, it was found that some of the introduced divinylsulfone did not function as a crosslinking point. From this, it is considered that one vinyl group possessed by divinylsulfone remains in an unreacted state and exists in the suizendinori polysaccharide.

Example 2
A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that the amount of divinyl sulfone was changed to 176 mg (150 μL, 1.5 mmol) in Example 1.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 5900% and the linear swelling change rate in the in-plane direction was 0.22%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 27300. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  When the compression elastic modulus in the water-swelled state of the water-swellable sheet obtained above was measured in the same manner as in Example 1, the compression elastic modulus was 455 kPa. Moreover, when the introduction rate of divinyl sulfone, the degree of swelling (q) per dry weight of the water-swellable sheet, the molecular weight between crosslinking points (Mc) and the crosslinking density were determined in the same manner as in Example 1, the introduction rate of divinyl sulfone was obtained. Was 16 mol%, the degree of swelling (q) per dry weight of the water-swellable sheet was 18, the molecular weight between crosslinks (Mc) was 900 g / mol, and the crosslink density was 10 mol%.

Example 3
In Example 1, a water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that the amount of divinyl sulfone was changed to 236 mg (200 μL, 2 mmol).

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 minutes, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 5100% and the linear swelling change rate in the in-plane direction was 0.31%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 16200. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  When the compression elastic modulus in the water swelling state of the water-swellable sheet obtained above was measured in the same manner as in Example 1, the compression elastic modulus was 595 kPa. Moreover, when the introduction rate of divinyl sulfone, the degree of swelling (q) per dry weight of the water-swellable sheet, the molecular weight between crosslinking points (Mc) and the crosslinking density were determined in the same manner as in Example 1, the introduction rate of divinyl sulfone was obtained. Was 22 mol%, the degree of swelling (q) per dry weight of the water-swellable sheet was 16, the molecular weight (Mc) between crosslinks was 800 g / mol, and the crosslink density was 11 mol%.

Example 4
A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that the amount of divinyl sulfone was changed to 294 mg (250 μL, 2.5 mmol) in Example 1.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 minutes, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 4650% and the linear swelling change rate in the in-plane direction was 0.42%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 11,000. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  When the compression elastic modulus in the water swelling state of the water-swellable sheet obtained above was measured in the same manner as in Example 1, the compression elastic modulus was 959 kPa. Moreover, when the introduction rate of divinyl sulfone, the degree of swelling (q) per dry weight of the water-swellable sheet, the molecular weight between crosslinking points (Mc) and the crosslinking density were determined in the same manner as in Example 1, the introduction rate of divinyl sulfone was obtained. Was 28 mol%, the degree of swelling (q) per dry weight of the water-swellable sheet was 10, the molecular weight between crosslinks (Mc) was 750 g / mol, and the crosslink density was 12 mol%.

Example 5
In Example 3, an aqueous solution containing 0.2 M sodium hydroxide and containing a suizendinori polysaccharide at a concentration of 0.8% by mass was used instead of the aqueous solution containing a suizenzinori polysaccharide at a concentration of 0.8% by mass. A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 3 except that it was used.

  The water-swellable sheet obtained above was immersed in water at 25 ° C. for 10 days, then taken out from the water and visually observed with the water-swellable sheet swollen with the water. It was not, and it was confirmed that it swelled greatly in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 23000% and the linear swelling change rate in the in-plane direction was 0.22%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 105300. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

Example 6
In Example 3, an aqueous solution containing 0.2 M hydrochloric acid and containing a suizendinori polysaccharide at a concentration of 0.8% by mass was used instead of the aqueous solution containing the suizendinori polysaccharide at a concentration of 0.8% by mass. Except for this, a water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 3.

  The water-swellable sheet obtained above was immersed in water at 25 ° C. for 10 days, then taken out from the water and visually observed with the water-swellable sheet swollen with the water. It was not, and it was confirmed that it swelled greatly in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 6400% and the linear swelling change rate in the in-plane direction was 0.74%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 8690. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

Example 7
In Example 3, an aqueous solution containing 0.2 M hydrochloric acid and containing a suizendinori polysaccharide at a concentration of 0.8% by mass was used instead of the aqueous solution containing the suizendinori polysaccharide at a concentration of 0.8% by mass. Except for this, a water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 3.

  The water-swellable sheet obtained above was immersed in water at 25 ° C. for 10 days, then taken out from the water and visually observed with the water-swellable sheet swollen with the water. It was not, and it was confirmed that it swelled greatly in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 16200% and the linear swelling change rate in the in-plane direction was 1.09%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 14900. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

Example 8
In Example 1, a water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that the concentration of the Suizendinori polysaccharide was changed from 0.8% by mass to 0.5% by mass. . It was confirmed that the compression modulus of the obtained water-swellable sheet was 156 kPa.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 12500% and the linear swelling change rate in the in-plane direction was 4.9%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 2460. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

Example 9
In Example 1, a water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that the concentration of the Suizendinori polysaccharide was changed from 0.8% by mass to 0.6% by mass. . The compression elastic modulus of the obtained water-swellable sheet was confirmed to be 190 kPa.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. The linear swelling change rate was 10200%, and the linear swelling change rate in the in-plane direction was confirmed to be 2.4%.

  Next, when the linear swelling change ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change ratio was 4190. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

Example 10
In Example 3, the plate in which the liquid crystal polysaccharide solution was spray-coated on a polyester plate having a flat surface so that the film thickness was about 20 μm was left in the atmosphere at 25 ° C. for 170 hours. A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 3 except that the time was changed to 190 hours.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 4500% and the linear swelling change rate in the in-plane direction was 0.30%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 15000. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy. Moreover, it was confirmed that the compression elastic modulus in the water swelling state of the water-swellable sheet obtained above is 231 kPa.

Example 11
In Example 3, the plate in which the liquid crystal polysaccharide solution was spray-coated on a polyester plate having a flat surface so that the film thickness was about 20 μm was left in the atmosphere at 25 ° C. for 170 hours. A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 3 except that the time was changed to 144 hours.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. It was confirmed that it was hardly swollen and greatly swollen in the thickness direction. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 5500% and the linear swelling change rate in the in-plane direction was 0.33%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 16700. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy. Moreover, it was confirmed that the compression elastic modulus in the water swelling state of the water-swellable sheet obtained above is 231 kPa.

Example 12
In Example 1, instead of an aqueous solution containing 0.2M sodium hydroxide and containing a suizendinori polysaccharide at a concentration of 0.8% by mass, 0.2M sodium hydroxide was contained, and xanthan gum was added in an amount of 0.1%. A water-swellable sheet having a thickness of about 20 μm was produced in the same manner as in Example 1 except that 20 mL of an aqueous solution containing 8% by mass was used.

  Next, after immersing the water-swellable sheet obtained above in 25 ° C. water for 10 days, the water-swellable sheet taken out from the water and swollen with the water was visually observed. Almost no swelling and large swelling in the thickness direction, confirming excellent swelling anisotropy. Therefore, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were measured in the same manner as in Example 1, the thickness direction of the water-swellable sheet was measured. It was confirmed that the linear swelling change rate was 4500% and the linear swelling change rate in the in-plane direction was 0.30%.

Example 13
Polyester having a flat surface with 50 mL of a liquid crystalline polysaccharide aqueous solution containing a suizendinori polysaccharide [average sugar residue molar mass: 180 g / mol, average mass: 250 mg (1.39 mmol)] at a concentration of 0.5 mass / volume% Spray coated onto a made plate. The plate was left in the atmosphere at 60 ° C. for 16 hours to dry the film, thereby obtaining a water-swellable sheet. When the obtained water-swellable sheet was peeled off from the plate and the thickness thereof was measured, the thickness was about 40 μm. Thereafter, a square test piece having a side length of 5 mm was cut out from the water-swellable sheet obtained above and heated to 120 ° C. for 2 hours in a thermostatic bath.

  Next, after immersing the water-swellable sheet obtained above in water at 25 ° C. for 1 day, the water-swellable sheet was taken out from the water and visually observed. It was confirmed that the film was greatly swollen in the thickness direction. Then, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were examined in the same manner as in Example 1, the water swelling property obtained above was examined. It was confirmed that the linear swelling change rate in the thickness direction of the sheet was 1600%, and the linear swelling change rate in the in-plane direction was 3.3%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 500. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  Next, a square-shaped test piece having a side length of 10 mm is cut out from the water-swellable sheet obtained above, and compression elasticity in a water-swelled state is used as a physical property of the water-swellable sheet using the obtained test piece. The rate was examined as in Example 1. As a result, it was confirmed that the compression elastic modulus in the water-swollen state was 141 kPa.

  When the degree of swelling (q) per dry weight and molecular weight (Mc) between crosslinking points of the water-swellable sheet obtained above were evaluated in the same manner as in Example 1, the degree of swelling (q) was 21, The point-to-point molecular weight (Mc) was 2550 g / mol.

  Moreover, when the crosslinking density of the water-swellable sheet obtained above was determined in the same manner as in Example 1, the crosslinking density was 3.5 mol%. In addition, it is thought that the crosslink density of the said swellable sheet has shown the density of the physical crosslink point formed by heat processing (same in a following example).

Example 14
Polyester having a flat surface with 50 mL of a liquid crystalline polysaccharide aqueous solution containing a suizendinori polysaccharide [average sugar residue molar mass: 180 g / mol, average mass: 250 mg (1.39 mmol)] at a concentration of 0.5 mass / volume% Spray coated onto a made plate. The plate was left in the atmosphere at 60 ° C. for 16 hours to dry the film, thereby obtaining a water-swellable sheet. When the obtained water-swellable sheet was peeled off from the plate and the thickness thereof was measured, the thickness was about 40 μm. Thereafter, a square test piece having a side length of 5 mm was cut out from the water-swellable sheet obtained above, and heated to 140 ° C. for 2 hours in a thermostatic bath.

  Next, after immersing the water-swellable sheet obtained above in water at 25 ° C. for 1 day, the water-swellable sheet was taken out from the water and visually observed. It was confirmed that the film was greatly swollen in the thickness direction. Then, when the linear swelling change rate in the thickness direction and the linear swelling change rate in the in-plane direction of the water-swellable sheet swollen with water were examined in the same manner as in Example 1, the water swelling property obtained above was examined. It was confirmed that the linear swelling change rate in the thickness direction of the sheet was 1300% and the linear swelling change rate in the in-plane direction was 1.6%.

  Next, when the linear swelling change rate ratio of the water-swellable sheet was determined based on the formula (I), the linear swelling change rate ratio was 826. From this, it can be seen that the water-swellable sheet obtained above swells greatly in the thickness direction and hardly swells in the in-plane direction, so that it has excellent swelling anisotropy.

  Next, a square-shaped test piece having a side length of 10 mm is cut out from the water-swellable sheet obtained above, and compression elasticity in a water-swelled state is used as a physical property of the water-swellable sheet using the obtained test piece. The rate was examined as in Example 1. As a result, it was confirmed that the compression elastic modulus in the water-swollen state was 202 kPa.

  When the swelling degree (q) per dry weight and molecular weight (Mc) between crosslinking points of the water-swellable sheet obtained above were evaluated in the same manner as in Example 1, the swelling degree (q) was 15, The point-to-point molecular weight (Mc) was 2460 g / mol.

  Moreover, when the crosslinking density of the water-swellable sheet obtained above was determined in the same manner as in Example 1, the crosslinking density was 3.7 mol%.

Comparative Example 1
In Example 1, an attempt was made to produce a water-swellable sheet in the same manner as in Example 1 except that 119 mg of aluminum chloride was used instead of divinyl sulfone as the water-soluble crosslinking agent. However, at the moment when aluminum chloride was added to an aqueous solution containing sodium hydroxide and suizendinori polysaccharide, the entire solution became mamako (dama), so it could not be dried into a sheet.

  The water-swellable sheet of the present invention includes, for example, an organ adhesion-preventing film for preventing the adhesion of organs during surgery, a bandage for wound treatment, a wound covering film, a cooling sheet, and a cushion sheet for organ preservation. It is expected to be used for various applications such as a body fluid absorbing sheet and a cell culture sheet.

Claims (3)

A water-swellable sheet comprising polysaccharides is used as a raw material, wherein the polysaccharide is a Aphanothece sacrum polysaccharide having a weight average molecular weight of 4 to 60 million, the thickness direction of the line when swollen with water A water-swellable sheet having a swelling change rate of 1000% or more and a linear swelling change rate in an in-plane direction of 10% or less. Raw material as a polysaccharide method of producing a water-swellable sheet comprising a used, using Aphanothece sacrum polysaccharide having a weight average molecular weight of 4,000,000 to 60,000,000 as the polysaccharide, aqueous the Aphanothece sacrum polysaccharide and divinyl sulfone It is dissolved in a solvent, a film is formed using the obtained suizendinori polysaccharide aqueous solution, and the formed film is dried for 2 to 300 hours in an atmosphere having an air temperature of 1 to 60 ° C. Item 2. A method for producing a water-swellable sheet according to Item 1 . Raw material as a polysaccharide method of producing a water-swellable sheet comprising a used, using Aphanothece sacrum polysaccharide having a weight average molecular weight of 4,000,000 to 60,000,000 as the polysaccharide, dissolving the Aphanothece sacrum polysaccharide in an aqueous solvent A film is formed using the obtained suizendinori polysaccharide aqueous solution, and the formed film is dried for 2 to 300 hours in an atmosphere having an air temperature of 1 to 60 ° C., and further dried. The method for producing a water-swellable sheet according to claim 1 , wherein the coated film is heated to a temperature of 80 to 160 ° C. to crosslink the suizendinori polysaccharide .