JPH09241396A - Production of composite substrate containing polysaccharide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite substrate which has a coating film having low restoring power and excellent water resistance. etc., by coating a substrate with a coating soln. contg. a polysaccharide to form a composite substrate having a coating film and thermally treating the substrate. SOLUTION: A substrate (e.g. paper, a plastic, a metal, or cloth) is coated with a coating soln. contg. a polysaccharide and thermally treated at 120 deg.C or higher (pref. 130-200 deg.C) for 5-60min to give a composite substrate having a coating film. If necessary, the coated substrate may be dried at 30-120 deg.C before the thermal treatment. The drying or the thermal treatment can be carried out with various types of apparatus, such as a tunnel drier, a drum drier, or a chamber drier.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a composite substrate such as having a coating film having excellent water resistance on a substrate, and more particularly to a coating liquid containing bacterial cellulose and other polysaccharides. The present invention relates to the above-mentioned manufacturing method and the composite substrate thus obtained, which is characterized in that the coating film obtained is subjected to heat treatment after being applied to the substrate.

[0002]

2. Description of the Related Art BC (bacterial cellulose) is edible and tasteless and odorless, so that it is used in the food field and has excellent water-based dispersibility, so that it maintains the particle size of foods, cosmetics or paints, and is a raw material for foods. It has industrial value as a dough strengthening, moisture retention, food stability improvement, low calorie additive or emulsion stabilization aid. BC has a fibril fragment width of 2 times as compared to cellulose produced from wood pulp or the like.
It is characterized by a small digit. Accordingly, the dissociated product of BC has various industrial uses as a reinforcing agent for polymers, especially aqueous polymers, based on such structural and physical characteristics of fibrils. A substance obtained by solidifying such a bacterial cellulosic dissociation product into a paper or solid form exhibits a high tensile elastic modulus, and therefore is expected to have excellent mechanical properties based on the structural characteristics of fibrils, and can be applied to various industrial materials. is there.

As one of such application examples, B has been conventionally used.
Attempts have been made to produce a coated paper by applying a coating liquid containing C onto paper or the like. However, when a coating solution containing only BC is applied to paper or the like, it is difficult to obtain a uniform coating film by agglomeration of BCs. Therefore, in order to improve the uniformity of the coating film, an example is known in which carboxymethyl cellulose is further added to a coating solution containing BC, or a special coating method called curtain coating is used (Japanese Patent Laid-Open No. HEI 5- 9895). Furthermore, what added the 3rd component other than BC and water to the aqueous suspension containing BC, and dehydrated and dried shows the outstanding viscosity restoration rate and sedimentation degree restoration rate, etc. when mixing and condensing again. It is known (Japanese Patent Application No. 7-3
29472).

[0004]

However, for example,
When trying to obtain a coating film with sufficient water resistance,
On the contrary, it is desirable that the restoration property is not as high as possible, and a coating film containing a polysaccharide such as BC having such a low restoration rate has not been obtained so far. The present inventors have now found that, for example, a composite substrate including a polysaccharide and a substrate can be heat-treated to form a coating film having excellent water resistance, and completed the present invention.

[0005]

That is, the present invention relates to a method for producing a composite substrate, which comprises forming a composite substrate comprising a polysaccharide and a substrate and heat-treating the composite substrate. Especially,
The present invention relates to a method for forming a coating film, which comprises applying a coating liquid containing a polysaccharide onto a substrate to form a composite substrate, and subjecting the resulting composite to heat treatment. As the polysaccharide, bacterial cellulose, which is a cellulosic substance that can be produced by culturing a cellulose-producing bacterium,
Carboxymethyl cellulose, xanthan gum and cellulose derivatives (methyl cellulose, hydroxypropyl cellulose, ethyl cellulose), xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, starch, starch starch, kudzu flour, positive starch, phosphorylated starch. , Corn starch, gum arabic, locust bean gum, guar gum, gellan gum, polydextrose, pectin,
Examples thereof include chitin, water-soluble chitin, chitosan, vegetable gum, hydrophilic cross-linked polymer, starch polyacrylic acid copolymer, tamarind gum, gellan gum, guar gum, and mixtures thereof. Among these, a mixture of BC and carboxymethyl cellulose or xanthan gum is particularly preferable. Those skilled in the art can appropriately select the concentration of the polysaccharide in the coating liquid and the blending ratio of each component depending on the types of the polysaccharide and the substrate, the heat treatment conditions, the purpose of use of the coated substrate and the like. Usually, the concentration of each component of the polysaccharide in the coating solution is 0.02 to 2.0% by weight. or,
The compounding ratio of BC and carboxymethyl cellulose or xanthan gum is usually in the range of 50: 1 to 1: 2. The heat treatment is at least about 120 ° C or higher, preferably in the range of about 130 ° C to about 200 ° C, usually about 5 ° C.
Minutes to about 60 minutes. At the time of heat-treating the composite substrate, the polysaccharide is still in suspension or gel, and does not need to be in a dry state. However, in some cases, a step of drying the coating film on the substrate may be performed before the heat treatment. This drying step itself has been conventionally performed, and the conditions thereof can be appropriately selected by those skilled in the art. For example, it can be carried out by means such as air drying in the range of about 30 ° C to about 120 ° C.

Any known method may be used as the drying method in the method of the present invention, for example, spray drying,
Examples include squeezing, air drying, hot air drying, and vacuum drying. Examples of the apparatus specifically used for the heat treatment or the drying treatment in the method of the present invention are as follows. That is, continuous tunnel dryer, band dryer, vertical dryer, vertical turbo dryer, multi-stage disk dryer,
Batch-type box-type drying equipment such as through-air drying equipment, rotary drying equipment, flash drying equipment, spray drying equipment, cylindrical drying equipment, drum drying equipment, screw conveyor drying equipment, rotary drying equipment with heating tubes, vibration transport drying equipment, etc. Drying apparatuses such as a through-air drying apparatus, a vacuum box-type drying apparatus, and a stirring drying apparatus can be used alone or in combination of two or more. As a method of supplying heat energy in the above device, for example,
Direct heating, radiant heating, and indirect heating can be mentioned. Among them, infrared heating, microwave heating, etc. are particularly preferable from the viewpoint of energy efficiency.

In the method of the present invention, both the heat treatment and the drying can be carried out by using the same apparatus and changing the temperature conditions. Bacterial cellulose is obtained by a conventional culture method such as static culture and aeration and agitation culture, and is preferably subjected to disaggregation treatment. Further, in the method of the present invention, as a specific method for applying the coating liquid containing the polysaccharide onto the substrate, any conventionally known means such as dipping, spraying, brush coating and curtain coater can be used. The substrate is made of, for example, a material such as paper, plastic, metal, and cloth, and its shape is any shape such as cloth, non-woven cloth, plate, sphere, rectangular parallelepiped, and fiber. It can also be implemented. It is also possible to carry out the process according to the invention on substrates which have already been subbed. In addition, a coating solution containing a polysaccharide may be added to a pigment, an adhesive, a latex, an enzyme, a fat or oil, a filler, an inorganic substance in a range that does not impair the water resistance of the obtained coating film, and further depending on the purpose of use. It is also possible to contain components such as powder and fibers. The present invention relates to the composite substrate itself obtained by the manufacturing method described above. Furthermore, the present invention provides a method for producing a composite substrate, which comprises heat-treating the above-mentioned polysaccharide into various substrates after forming a composite substrate by plowing, internally adding, impregnating, mixing, etc. Also involved.

In the present specification, the "dry" state is not an absolutely dry state in which the water contained in the dried product is completely absent. That is, it is about 25% or less of the total weight of BC and the third component contained in the dried product. The appearance of the dried product in such a state is almost dry. BC
In addition, the third component of the present invention often has a polar group such as a hydroxyl group in the molecule and thus has an action of adsorbing water, and in the case of a low molecule, it has a form like crystal water Even if you obtain a dried product that seems to be dried by the method and device described above because it has a function of retaining water, if you leave it in normal air, the water vapor in the air To reach an equilibrium state. When storage is required, the water activity value of the dried product of the present invention must be lower than or equal to a level at which microorganisms cannot grow. 0.9 at the highest
Hereinafter, a water activity value of 0.75 or less is desired.

In the method of the present invention, it is preferable that the cellulosic material has been subjected to disaggregation treatment. The disintegration phenomenon of bacterial cellulose is considered to be a phenomenon in which a stress generated inside the cellulose due to a mechanical external force or the like deforms or breaks it. Accordingly, the disaggregation treatment of bacterial cellulose can be performed by applying a mechanical external force to bacterial cellulose. Further, the disaggregation treatment can be carried out by acid hydrolysis, enzymatic hydrolysis and a bleaching agent. The mechanical external force referred to herein includes, for example, stresses such as tension, bending, compression, torsion, impact, and shearing, but generally includes compression, impact, and shearing stress. The actual application of these mechanical external forces to bacterial cellulose can be achieved by using, for example, a mixer, a polytron, an ultrasonic oscillator or the like.

In the disaggregation treatment by the mixer, the mechanical external force mainly consists of the impact force caused by the collision of the stirring blade and the bacterial cellulose and the shearing force generated by the displacement phenomenon due to the speed difference of the medium. In the disaggregation process using Polytron, the mechanical external force is the compressive force of bacterial cellulose sandwiched between the external teeth and the internal teeth, the impact force of the collision of high-speed rotating teeth with bacterial cellulose, the static external teeth and the high speed of stationary external teeth. The shear stress generated in the medium existing in the gap between the rotating internal teeth is mainly involved. In the disintegration by the ultrasonic pulverizer, the mechanical external force is mainly cavitation (cavity phenomenon) continuously generated in the medium due to the oscillation of the ultrasonic oscillating unit, and significant shear stress locally generated. The defibration treatment of the present invention can be performed by any method other than the above-mentioned specific examples as long as a certain load (mechanical external force) can be applied to the bacterial cellulose. Other disaggregation treatment conditions can be appropriately selected by those skilled in the art.

The disaggregation treatment has been described above. The disaggregation treatment according to the present invention is performed after stirring culture of the cellulose-producing bacterium,
It is obvious to those skilled in the art that the present invention is not limited to an independent secondary operation performed on bacterial cellulose separated and purified from a culture solution. That is, the stirring operation has a function of disaggregating the bacterial cellulose, and in the stirring culture, the dissociation treatment of the bacterial cellulose can be sufficiently performed even by the stirring function for the purpose of culturing. Furthermore, the same can be said for the operations of separating, washing, purifying and transporting the bacterial cellulose obtained by stirring culture, and additional disaggregation treatment in these operations is also included in the disaggregation treatment of the present invention. Please note.

The agitation culture as referred to in the present invention is a culture method carried out while agitating a culture solution, and the agitation effect received during the agitation culture causes the structure of bacterial cellulose to decrease, for example, due to a decrease in crystallization index. The crystal parts change so as to increase. As the stirring means, for example, an impeller, an airlift fermenter, a pump-driven circulation of fermentation broth, a combination of these means, and the like can be used. The culture operation method includes a so-called batch fermentation method, a fed-batch batch fermentation method, a repeated batch fermentation method and a continuous fermentation method. Furthermore, a method for producing a cellulosic substance by circulating a culture solution containing bacterial cells between a culture apparatus and a separation apparatus described in Japanese Patent Application No. 6-192287 in the name of the present applicant. And separating the cellulosic substance, which is a product, from the cells and the culture solution, and culturing the cellulosic bacteria described in Japanese Patent Application No. 6-192288 in the name of the present applicant. A method for producing a cellulosic material by continuously extracting a culture solution from a culture system and supplying a new culture solution having substantially the same volume as the amount withdrawn during the culture period. The production method is characterized in that the concentration of the cellulosic substance in the culture solution is kept low.

As a tank for performing the stirring culture,
For example, stirring tanks such as jar fermenters and tanks,
In addition, baffled flasks, Sakaguchi flasks, and air-lift type stirring tanks can be used, but are not limited thereto. In the stirring culture according to the present invention, at the same time as stirring,
Ventilation may be performed if necessary. The aeration referred to here may be any of an oxygen-containing gas such as air and an oxygen-free gas such as argon and nitrogen. These gases may be used by those skilled in the art according to the conditions of the culture system. Will be selected as appropriate. For example, in the case of anaerobic microorganisms, if an inert gas is ventilated, the culture solution can be stirred by the bubbles. In the case of aerobic microorganisms, the culture solution can be agitated while supplying oxygen necessary for the growth of the microorganisms by aerating an oxygen-containing gas.

The cellulose-producing bacterium producing BC used in the present invention is, for example, Acetobacter xylinum subsp. S, which is represented by BPR2001 strain.
ucrofermentans ), Acetobacter xylinum ( Acet
bacterium xylinum ) ATCC 23768, Acetobacter xylinum ATCC 23969, Acetobacter
Pasteurianus ( A. pasteurianus ) ATCC1024
5, Acetobacter xylinum ATCC 14851,
Acetic acid bacteria (genus Acetobacter) such as Acetobacter xylinum ATCC11142 and Acetobacter xylinum ATCC10821, and others, Agrobacterium, Rhizobium, Sarsina, Pseudomonas,
The genera are Achromobacter, Alcaligenes, Aerobacterium, Azotobacter and Zooglare, and various mutants created by subjecting them to mutation treatment by a known method using NTG (nitrosoguanidine) or the like. The BPR2001 strain was deposited on February 24, 1993 at the Patent Microorganisms Depositary Center of the Institute of Biotechnology and Industrial Technology, Ministry of International Trade and Industry (accession number FERM P-
13466) and subsequently transferred to a deposit under the Budapest Treaty on the International Recognition of Patent Deposits on February 7, 1994 (accession number FERM BP-4545).

Examples of the chemical mutation treatment method using a mutagen such as NTG include, for example, Bio Factors, Vol. 1, p. 297-302.
(1988) and J. Gen. Microbiol, Vol. 135, p. 2917-2.
929 (1989). Therefore, those skilled in the art can obtain the mutant strain used in the present invention based on these known methods. The mutant strain used in the present invention can also be obtained by other mutation methods, for example, irradiation. Among the cellulose-producing bacteria created by the above-mentioned method, a high polymerization degree having a weight average polymerization degree of not less than 1.6 × 10 ⁴ , preferably 1.7 × 10 ⁴ or more in terms of polystyrene is obtained by aeration and stirring culture. Or a strain that produces bacterial cellulose having a high degree of polymerization having a weight-average degree of polymerization in terms of polystyrene of 2.0 × 10 ⁴ or more by producing the bacterial cellulose or by culturing it in a static state. Among the bacterial cells producing a high degree of polymerization that can be used in the present invention, BPR
3001A was deposited on June 12, 1995, with the Patented Microorganisms Depositary Center, Biotechnology and Industrial Technology Research Institute, Ministry of International Trade and Industry, under the accession number FERM P-14982. In general, it is known that the higher the degree of polymerization of a polymer, the higher the strength and elastic modulus of the polymer material. Similarly, in the case of bacterial cellulose, various products obtained using high polymerization degree bacterial cellulose as a raw material have higher strength and elasticity than those obtained using relatively low polymerization degree bacterial cellulose as a raw material. High rate. Therefore, when it is desired to produce a product having a high strength and an elastic modulus, the use of bacterial cellulose having a high degree of polymerization as described above provides a higher effect.

The weight average degree of polymerization of various celluloses such as BC in the present invention is determined by GPC having RI as a detector.
It measures as follows using a system (Tosoh HLC-8020). Various cellulose samples were treated with fuming nitric acid-phosphorus pentoxide solution by WJ Alexander, RL Mitchell, Anal.
It is nitrated by the method of ytical chemistry 21, 12, 1497-1500 (1949). A nitrated cotton linter is used as a control. The cellulose nitrate is dissolved in THF (Wako Pure Chemicals first grade) at a concentration of 0.05%, and then filtered through a 1.0 μm pore size filter. THF is also used as the eluent for GPC. Flow rate is 0.5
ml / min, the pressure is 10-13 kgf / cm ² , and the sample injection volume is 100 μl. Column is TSKgel GMH
-Using HR (S) (7.5 ID x 300 mm x 2) and guard column (HHR (S)) (Tosoh Co., Ltd.) 35
Measure in ° C. The standard polystyrene (Tosoh) is used to calculate the molecular weight, and the relative molecular weight in terms of polystyrene is calculated. Elution time (t) and logarithm of molecular weight (log M) using polystyrene having a molecular weight of 2 × 10 ⁷ to 2630
For the cubic equation: (log M = At ³ + Bt ² + Ct
+ D) is approximated to create a standard curve.
Molecular weight: Tosoh's data processing machine (SC-8020)
The weight average molecular weight is calculated by a program (ver. From these molecular weight values, the weight average polymerization degree is calculated in consideration of the degree of substitution after nitration.

In the composition of the medium used for stirring culture of the present invention, carbon sources include sucrose, glucose, fructose, mannitol, sorbitol, galactose,
Maltose, erythritol, glycerin, ethylene glycol, ethanol and the like can be used alone or in combination. Furthermore, starch hydrolyzate containing these, citrus molasses, beet molasses, beet juice,
It is also possible to use sugar cane juice, fruit juice such as citrus fruits, etc. in addition to sucrose. As the nitrogen source, ammonium salts such as ammonium sulfate, ammonium chloride and ammonium phosphate, nitrates, organic or inorganic nitrogen sources such as urea can be used, or Bacto
-Natural nitrogen-containing nutrient sources such as Peptone, Bacto-Soytone, Yeast-Extract, and soybean concentrate may be used. Amino acids, vitamins, fatty acids, nucleic acids, 2,7,9 as organic micronutrients
-Tricarboxy-1H pyrrolo [2,3,5] -quinoline-4,5-dione, sulfite waste liquor, ligninsulfonic acid, etc. may be added.

When using an auxotrophic mutant strain that requires amino acids and the like for growth, it is necessary to supplement the required nutrients. As the inorganic salts, phosphates, magnesium salts, calcium salts, iron salts, manganese salts, cobalt salts, molybdates, red blood salts, chelate metals and the like are used. Furthermore, inositol, phytic acid, pyrroloquinoline quinone (PQQ) (Japanese Patent Publication No. 5-1718; Mitsuo Takai, Paper and Paper Cooperative Journal, Vol. 42, No. 3, 237-2).
44), carboxylic acid or a salt thereof (Japanese Patent Application No. 5-1914).
No. 67), invertase (Japanese Patent Application No. 5-331491)
) And methionine (Japanese Patent Application No. 5-335564) can be added to the medium as appropriate. For example, when acetic acid bacterium is used as a production bacterium, the pH of the culture is controlled at 3 to 7, preferably around 5. The culture temperature is 10 to 40 ° C, preferably 25 to 3
Perform at 5 ° C. The oxygen concentration supplied to the culture device is 1 to
100%, preferably 21 to 80%. Those skilled in the art can appropriately select the composition ratio of each component in the medium, the inoculation of the cells into the medium, and the like, depending on the culture method.

The bacterial cellulose of the present invention can be produced, for example, by the following method. Bacterial cellulose obtained by aeration and agitation culture is separated from the culture solution by a centrifugation method, a filtration method or the like. The bacterial cells produced by the method of the present invention may be recovered as the bacterial cells as they are, and may be further treated to remove impurities other than the cellulosic material including the bacterial cells contained in the substance. To remove impurities, washing with water, pressure dehydration, washing with diluted acid, washing with alkali, treatment with bleach such as sodium hypochlorite and hydrogen peroxide, treatment with cell lysing enzymes such as lysozyme, sodium lauryl sulfate, Impurities can be almost completely removed from the cellulosic material by performing a treatment with a surfactant such as deoxycholic acid, washing with heat in the range of room temperature to 200 ° C., alone or in combination. The cellulosic material thus obtained in the present invention includes cellulose, a substance containing a heteropolysaccharide having cellulose as a main chain, and a substance containing glucan such as β-1,3, β-1,2. In the case of the heteropolysaccharide, components other than cellulose include hexoses such as mannose, fructose, galactose, xylose, arabinose, rhamnose, and glucuronic acid, pentoses, and organic acids. These polysaccharides may be a single substance, or two or more polysaccharides may be mixed by hydrogen bonding or the like.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples, but the examples do not limit the present invention.

[0021]

【Example】

Example 1 Production and Disintegration of Bacterial Cellulose (1) Preparation of Seed Bacterial Solution (Proliferation of Microorganisms) Cellulose-producing microbes were multiplied by a flask culture method. Basic composition of 40 g / L fructose, 1.0 g / L potassium phosphate, 0.3 g / L magnesium sulfate, 3 g / L ammonium sulfate, 5 g / L bacto-peptone, 1.4 ml / L lactic acid, initial pH 5.0 Medium 100
BPR into a 750 ml Roux flask into which the
1 ml of a cryopreserved bacterial solution of the 2001 strain (FERM BP-4545) was inoculated, and statically cultured at 28 ° C. for 3 days in a constant temperature incubator. After the seed culturing, the Roux flask was shaken well, and the contents were subjected to gauze filtration under aseptic conditions to obtain a seed bacterial solution.

(2) Production of Bacterial Cellulose by Stirring Cultivation Aseptically inoculating 60 ml of the above seed bacterial solution into a small jar fermenter (total volume of 1000 ml) in which 540 ml of sterilized medium for stirring culture described later is put. 20 at 30 ° C
PH for 1 hour or 30 hours with 1N NaOH or 1N H
While controlling to 5.0 with ₂ SO ₄ , the stirring speed was initially 400 rpm, and the dissolved oxygen (DO) was 3.0.
Stirring culture was performed with a jar fermenter while automatically controlling the number of revolutions so as to fall within 0 to 21.0%. For the stirring culture, a medium having the following composition was used. Fructose 40 g / L, KH ₂ PO ₄ 1.0 g / L, MgSO ₄ 0.3 g / L, (NH ₄ ) ₂ SO ₄ 3 g / L, Bacto-Soytone (manufactured by Difco) 5 g / L and sono (soybean) 5 g / L Initial pH 5.0 After cultivation, the solids in the jar fermenter were collected, washed with water to remove the medium components, and then placed in a 1% NaOH aqueous solution at 110 ° C. The cells were removed by treatment for 20 minutes. Further, the produced cellulose was washed with water until the washing liquid became nearly neutral to obtain bacterial cellulose.

(3) Disintegration treatment of bacterial cellulose Water is added to the washed bacterial cellulose obtained by the stirring culture method of (2), and a suspension having a disintegration treatment concentration of about 0.2% by weight (bacteria cellulose dry weight / volume) is added. A suspension was prepared. Next, this suspension was disintegrated at 25 ° C. for 3 minutes using a stirrer (Blender manufactured by Ooster Co.). The rotation speed of the stirrer was set to the highest level. By this disaggregation treatment, a BC disaggregated product was obtained from the stirring culture. The concentration of BC in the above is such that after the solid content in a wet state is taken out from the culture solution by centrifugation, it is immersed in a 0.2N sodium hydroxide solution of 20 times the solid content at 100 ° C. for 1 hour. By doing so, the cells other than bacterial cellulose and the components of the medium were removed, and then the cells were thoroughly washed with water, dried, and calculated from the dry weight.

Example 2 Carboxymethylcellulose (hereinafter "CMC", manufactured by Nacalai Chemical Co., Inc.) and xanthan gum (manufactured by Dainippon Pharmaceutical Co., Ltd.) were dissolved in the 0.1% concentration of BC disaggregated product obtained in Example 1 to prepare a coating solution. A mixed solution was prepared. Each concentration is 0.0
It was set to 5% and 0.1%. Filter paper (Advantech Toyo No. 2) and nylon plain weave mesh (3
00 mesh) was dipped to coat each surface with the mixed solution. 10 after coating
It was dried and heat-treated under the conditions of 5 ° C. for 10 minutes or 132 ° C. for 60 minutes. After the heat treatment, the coating film was immersed in water while being attached to the substrate (filter paper and mesh). The immersion treatment was performed in a baffled 300 ml Erlenmeyer flask.
This was performed for one day while stirring at rpm. After the dipping treatment, the peeled state of the coating film was visually observed. The additive concentration was adjusted to 0.
The results for the case of 05% are shown in Table 1, and the concentration of the additive is 0.1%.
The results in the case of are shown in Table 2.

Table 1 ────────────────────────────────── Condition of heat treatment Substrate additive Detachability after dipping treatment ────────────────────────────────── 105 ℃ Filter paper CMC Xanthan gum 〃 Mesh CMC 〃 Xanthan gum 〃 132 ℃ Filter paper CMC Almost no peeling Xanthan gum 〃 Mesh CMC 〃 Xanthan gum 〃 ───────────────────────────────────

Table 2 ──────────────────────────────────── Heat treatment conditions Substrate additive After dipping treatment Peelability ──────────────────────────────────── 105 ℃ Filter paper CMC Almost with peeling of the coating film The filter paper is also destroyed and the fiber layer is floating. Xanthan gum 〃 mesh CMC The coating film is almost peeled off, and the thin film of the coating film is observed. Xanthan gum 〃 132 ℃ Filter paper CMC Almost no peeling and the filter paper is not destroyed at all Xanthan gum 〃 Mesh CMC 〃 Xanthan gum 〃 ─────────────────────────────────────

Example 3 Among the experiments described in Example 2, the coating on the substrate was carried out by hand spraying the coating solution containing the disaggregated material. Other experiments were performed in the same manner as in Example 2. When the properties of the coating film were observed with the naked eye, it was found that a more uniform coating film could be obtained by spraying and coating than by dipping. As a result of performing the heat treatment in the same manner as in Example 2, the same results as in Table 1 and Table 2 were obtained.

Example 4 Disaggregation of 0.1% BC prepared in Example 1, 0.
A 1% CMC solution, a 0.1% xanthan gum solution, and water were applied to the filter paper in the same manner as in Example 2. After coating, heat treatment was performed at 105 ° C. or 132 ° C. in the same manner as in Example 2 to form a coating film on the surface of the filter paper. The filter paper on which this coating film was formed was immersed in the same manner as in Example 2, and then the peeling state of the coating film and the breaking state of the filter paper were visually observed. As a result, in the case of the 105 ° C. dried product, the coating film was peeled off and the filter paper was destroyed. In contrast, 1
Water and 0.1% BC when treated at 32 ° C
In the case of the product coated with, the filter paper was destroyed, but 0.1
For those coated with% CMC or xanthan gum,
No peeling of the coating film or breakage of the filter paper was observed.

Example 5 CM was added to the disaggregated product of BC having a concentration of 0.1% obtained in Example 1.
C and xanthan gum were added and dissolved to prepare a mixed solution. The concentration of the additive is 20 in sequence with respect to BC.
% And 50%. The mixed solution was air-dried on a polypropylene plate at 80 ° C. to obtain a sheet-like dried material having a thickness of about 100 μm. After heat-treating the sheet-like material under various conditions as shown in Table 3, the sheet-like dried material is placed in water and allowed to stand for 2 minutes, and then stirred at 1000 rpm for 30 minutes using a magnetic stirrer. To prepare a resuspension. The concentration of BC in this suspension was adjusted to be 0.1%, which is the same as the concentration of the disintegrated product before drying. The centrifugal sedimentation degree of the obtained suspension was measured according to the following method. Method for measuring centrifugal sedimentation Suspension with bacterial cellulose (BC) concentration of 0.2% 1
30 ml of 0 ml in a 15 ml Falcon tube
After centrifugation at 00 rpm for 15 minutes, the volume was expressed as a ratio of the volume of the sedimented portion to the whole. The larger the value of the degree of sedimentation, the harder the sedimentation, and the more dispersed the particles. The value of the sedimentation degree recovery ratio (the sedimentation degree of the disaggregated matter after drying and condensate / the sedimentation degree of the disaggregated matter before drying) was used. The results are shown in Table 3.

[0030] All% figures are centrifugal sedimentation values. Measurement is not possible for solidified products.

[0031]

[Effect] By heat-treating the coating film containing the polysaccharide,
It was possible to obtain a coating film that had no restorability and was excellent in water resistance and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Morinaga 3-2-1, Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Biopolymer Research Co., Ltd.

Claims (8)

[Claims] 1. A method for producing a composite substrate, which comprises forming a composite substrate comprising a polysaccharide and a substrate and heat-treating the composite substrate. 2. The method according to claim 1, wherein a composite substrate having a coating film is formed by applying a coating liquid containing a polysaccharide onto the substrate. 3. The method according to claim 1, wherein the polysaccharide contains at least bacterial cellulose. 4. The method of claim 1, 2 or 3 wherein the polysaccharide comprises carboxymethyl cellulose or xanthan gum. 5. The method according to claim 1, wherein the heat treatment is performed at a temperature of at least about 120 ° C. or higher. 6. The method according to claim 2, further comprising a step of drying the coating film on the substrate before the heat treatment. 7. The method according to claim 1, wherein the bacterial cellulose is obtained by aeration stirring culture. 8. A composite substrate obtained by the method according to claim 1.