KR790001098B1 - Method for producing paper composed mainly of pullulan fibers - Google Patents

Abstract

A method for producing paper composed mainly of pullulan fiber which is soluble and easily disintegratable in water was described. The paper was produced by subjecting a suspension of pullulan fibers which is soluble in water, edible, and nondigestible in the digestive organs of man, or suspension of said pullulan fibers in admixture with vegetable fibers such as wood fiber (pulps), flax or ramie fiber.

Description

Manufacturing method of paper mainly based on pullulan fiber

The present invention relates to a novel paper.

More specifically, the present invention relates to a method for producing special paper based on pullulan fibers.

The special paper of the present invention is mixed with plant fiber such as wood fiber (pulp), flax and remy fiber in the pullulan fiber or pullulan fiber which is soluble in water, edible and indigestible in the human digestive system. It is a method of manufacturing a special paper which dissolves in water and disintegrates easily by papermaking a suspension of pullulan.

A special paper of this paper has been proposed as a secret paper paper, but a paper obtained as a natural carbohydrate fiber which dissolves very rapidly in water, is edible, non-human, and non-digestible like the paper of the present invention has been proposed. There was no.

It is an object of the present invention to provide a novel paper adjusted to pullulan fibers or a mixture of pullulan fibers and plant fibers.

Another object of the present invention is to provide a method for producing this novel paper.

Other objects and conveniences of the present invention will become apparent from the following description.

Features of the present invention are as follows.

(1) The raw material pullulan used in papermaking in the present invention can be obtained at a relatively low price since it is a polysaccharide which is a cloth that can be produced in large quantities by culturing microorganisms.

(2) Since the raw material pullulan has high water solubility, the paper of the present invention dissolves quickly when immersed in water, and collapses when discarded outdoors, so that it can be used as a secret paper sheet.

(3) Since raw material pullulan is decomposed by microorganisms existing in nature, it does not directly or indirectly cause pollution by the paper of the present invention.

(4) Raw materials Pullulan is edible, non-digestible, and water soluble, so the paper of the present invention is used as an inner packaging material of pharmaceuticals such as powders or tablets, or foodstuffs such as instant food seasonings, powdered teas and koops. It can be taken as a medicine or edible as food, so there is no need to remove it.

(5) Raw materials Pullulan can be freely processed into fibers of various shapes, so that fibers can be freely adapted to the purpose of papermaking.

(6) The pullulan paper of the present invention is stronger than wood pulp paper because of its high strength and bending strength, so that it does not require special coating or sizing agents.

(7) The pullulan paper of the present invention has a good hydrophilicity, so that the ink sensitivity is not only good, but also the ink is not smeared, which is suitable for printing and writing.

(8) Since the pullulan paper of the present invention is heat adhesive, it can be processed very easily.

Pullulan used in the present invention is a linear polymer having monomers repeatedly bonded by α-1 and 6-bonds of maltotriose, a trimer of glucose, and has a molecular structure represented by the following structural formula.

(Where n is an integer of 20 to 10,000 indicating the degree of polymerization).

Pullulan has only been known as water soluble viscous, and its physical properties and method of use have not been studied until now.

For this reason, pullulan was actually an unknown compound. Because pullulan is a linear compound different from polysaccharides such as starch in its molecular structure, it can be synthesized by chemical or other operations using enzymes.

However, it is obtained as a viscous secretion in the culture medium of strains belonging to the incomplete microorganisms, Pularia pullulans. H, Bender, J, Lehmann Biochem, Biophys. Acta, 36, 309 (1959) Seinosuge Ueda: Journal of Industrial Chemistry , 67, 757 (1964) Pullulan is partially derived from carbon as a source of carbon and crystalline glucose (hereinafter referred to as DE), which is 20-70% equivalents of sugars and / or dextrins, ie, starches obtained by hydrolysis of acids or enzymes. It is prepared by a process comprising culturing strains that produce pullulan in a liquid incubator containing hydrolyzed starch.

The strains that can be used to produce pullulan are: Pullulaia fermentans var Fermentans IFO 6401, Pullulaina fermentans bar Fusca IFO 6402, Pullula Pullularia pullulans AHU 9553 includes various strains belonging to pullularia such as Pullularia pullulans IFO 6353, Pullularia pullulans IFO 4464, and the like. . These strains should be selected so that pullulan can be obtained with a suitable degree of polymerization by their special use.

Starches used as carbon sources include corn, cereal starches such as wheat starch, and root or tuber starches such as sweet potatoes, potatoes, and tapioca starches.

Partially hydrolyzed starch syrups used include those made from purified starch by hydrolysis of acids or enzymes. Products with D. E of 20-70% are suitable, with 35-60% being suitable. to be.

The concentration of partially hydrolyzed starch syrup in the incubator is about 3-30%.

However, in terms of yield of pullulan 5-15% is suitable. The nitrogen source used in the incubator usually contains organic or inorganic nitrogen compounds.

Ordinary inorganic salts such as potassium phosphate, sodium chloride, magnesium sulfate, ferrous sulfate and the like are also used.

Suitable initial pH is 5.0-7.5 and suitable incubation temperature range is 24-30 ° C.

Incubation takes 3 to 8 days and the best pullulan yield is obtained with no residual saccharides left in the culture.

After incubation, the solution is heated to inactivate enzymes and the cells are removed from the solution by centrifugation.

The solution is then precipitated by the addition of an organic solvent, such as methanol or the like (or more) in volume or volume, to recover pullulan from the solution.

The recovered pullulan is repeatedly dissolved in water, precipitated and purified by an organic solvent, and then dried to obtain pullulan powder.

Pullulan is a white, tasteless, and odorless powder, and the degree of decomposition as various digestive enzymes is one-tenth of that of starch.

In addition, the molecular weight of pullulan is controlled by the pH of the incubator or the concentration of phosphate (Japanese Patent Application Publication 42894/74).

The molecular weight of pullulan used in the present invention is not particularly limited, but is preferably 10,000 to 5,000,000, preferably 50,000 to 1,000,000.

An example of a pullulan manufacturing process is as follows.

Partially hydrolyzed starch of the strain Pullularia pullulans IFO 6353 10%, K ₂ HPO ₄ 0.5% NaCl 0.1%, MgSO ₄ 7H ₂ O 0.02%, (NH ₄ ) ₂ SO ₄ 0.66%, Yeast extract 0.04 Incubate at 24 ° C for 5 days in an incubator containing%.

The culture is separated from the cells by centrifugation and injected with matanol to obtain a pullulan precipitate.

After dissolution of water and precipitation of methanol, the white pullulan is separated, washed with methanol and dried to obtain a dry pullulan having a yield of 60 to 70% based on the amount of starch. Various processes are employed to produce papermaking fibers in Pullulan. For example, a powder or agglomerate of hydrous pullulan having a moisture content of 10% or more is extruded through pores while being heated and dissolved at 80 to 160 ° C, followed by dry cooling to obtain long pullulan fibers. The fibers thus obtained are cut into suitable lengths to make short pullulan fibers.

Alternatively, 5-15% aqueous solution of rollulan is injected with vigorous stirring together with an equivalence of a hydrophilic organic solvent such as acetone, or a lower alcohol such as metaphenol or ethanol to precipitate the pullulan as a fibrous white precipitate, and then It is filtered or centrifuged.

This precipitate is an aggregate of fine pullulan fibers and does not dissolve in organic solvents.

In the present invention, the papermaking operation is usually carried out by a method, and the concentration of the raw fiber is suitably about 0.3 to 1.0%.

Since the raw fiber is a water-soluble pullulan fiber, the fiber may be uniformly dispersed using a hydrophilic lower alcohol such as methanol, ethanol or isopropanol and a hydrophilic organic solvent such as acetone or a mixture thereof at a concentration of 60 to 100%. Disperse.

It is to be noted that the pullulan fiber is pulled into the pullulan fiber, so the pullulan fiber is water-soluble, so it is very weak in the absorption swelling state and is easily broken. It should also be noted that the pullulan fibers do not need to be entangled because they adhere to each other when heated and pressurized properly in the absorbed state.

However, when the heating pressure is excessive, these fibers adhere completely to form a film. Therefore, care must be taken with care and attention to the above points.

That is, in the beating process, in particular, it is necessary to consider the minimum necessary for uniformly dispersing the pullulan fibers precipitated in the pullulan aqueous solution, and this limit can be achieved by the degree of vigorous stirring.

In addition, dispersing liquid is injected into the paper wire screen according to the weight of the paper, and the water of the paper web can be removed as much as the fiber amount of the paper in front of the couch roll. Adjust to%.

In this way, the moisture in the paper-based paper can be completely removed by pressing rolls, so that the fiber content of the paper-paper in front of the drying cylinder is about 40%.

In particular, it is particularly necessary to completely remove the moisture in the pressing roller and to raise the temperature of the drying roller to about 20 ° C. to 60 ° C. to complete most of the drying.

The final calender roller is passed through a sheet of water reduced to about 15% of moisture to ensure proper heating and pressurization. If the paper is pressed strongly to a temperature of 100 ° C. or higher, there is a risk of filming.

As the pullulan fiber used in the present invention, the pullulan short fiber obtained by the above-mentioned melt spinning, the pullulan fiber produced by the hydrophilic organic solvent rather than the aqueous solution, and the pullulan fiber produced by other suitable methods are used.

When these pullulan fibers are heated and pressurized by a paper machine, they form a tough paper without adding a sizing agent or a special agent. In this case, paper pulp can be mixed with 10% to 80% of the total fiber, such as wood pulp.

Depending on the purpose of use, wood pulp, flax and ramie fibers can be freely mixed with the pullulan fiber. However, when a large amount of wood fiber is mixed with the pullulan fiber, an appropriate sizing agent is preferably added.

The paper produced by the present invention is a paper having a tough lipid and elasticity. However, if paper is made from pullulan fiber alone, the cut strength is somewhat lowered, but the elasticity of the paper is a weight of polyalcohols such as glycerin, ethylene glycol, sorbitol, propylene glycol or maltitol as plasticizers. It can be adjusted by mixing from 1 to 40%.

In addition, the strength of paper can be increased by mixing pullulan fibers with plant fibers such as wood fibers.

In this way, pullulan fiber or paper containing this fiber and plant fiber is similar in texture to Japanese paper, so the cotton is even and lint-free.

The surface smoothness and gloss of the paper can be increased or decreased by adjusting the pressure and temperature of the calender roller.

The pullulan paper of the present invention has good sensitivity of the printing ink at the time of printing, not only fluffing, but also writing ink smoothly without smearing or bleeding. The pullulan paper also dissolves faster in water than in polyvinyl alcohol or similar or other starch films, and swells and dissolves in cold water within seconds. This dissolution rate is many times faster than that of the polyvinyl alcohol paper or starch film.

In addition, pullulan is toxic and hardly invaded by digestive enzymes. Therefore, foods or foods packaged with pullulan fiber alone can be used freely as a packaging material for foods and medicines for diabetics because the paper is not only dissolved but also calories.

In addition, this pullulan paper is used for special purposes as a paper for secret documents that are dissolved in water because its capacity is several times faster than other similar papers or films.

Even if paper contains wood fibers, the wood fibers are completely collapsed, so there is little concern about pollution problems.

As described above, paper composed only of pullulan fibers can be used as a wrapping paper for pharmaceuticals, instant foods, or wrapping paper, and paper made of pullulan and plant fibers can be used as secret documents or securities paper.

In addition, since these papers have high water solubility, they can be used as substitutes for toilet paper, thin paper, and physiological menstrual cotton, and they can be disposed of conveniently because no pollution occurs.

Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.

Example 1

Preparation of Pullulan Fiber.

Pullularia pullulan IFO 4464 was used as pullulan-producing strain.

In order to culture this strain was prepared an incubator comprising a composition as follows. Enzymatically digested starch syrup (D. E 40) was used as the carbon source.

Composition of the incubator:

10% carbon source

K ₂ HPO ₄ 0.2%

Peptone 0.2%

NaCl 0.2%

MgSO _{4 7} H ₂ O 0.04%

FeSO _{4 7} H ₂ O 0.001%

100 ml of the culture with the composition was placed in a 500 ml flask and sterilized by heating by a normal method.

After 2 days of incubation, the strain obtained by spawn-cultivation for 2 days was inoculated into the culture solution contained in the flask and then incubated vigorously with a rotary stirrer at pH 7.5 at 27 ° C. for 5 days under vigorous stirring. The resulting viscous solution was centrifuged to remove the cells, and 0.5 wt% of activated carbon was added based on the weight of the solution, followed by filtration to obtain a clear colorless liquid. To the transparent colorless liquid, isopropanol was vigorously stirred, and twice the amount of this liquid volume was added. White fibrous pullulan immediately precipitated.

The precipitate was collected by filtration to obtain 65% pullulan (as anhydride) having an average molecular weight of 250,000 based on the raw material starch. The wet pullulan fiber thus obtained is referred to as pullulan fiber A below.

Pullulan fiber A is reduced to 15% of moisture and powderized, and the fine pullulan fiber is extruded by tensile spinning by sealing the pores under a pressure of 100 to 150kg / cm 2 at a temperature of 100 ° C to 160 ° C using a heat-mixing spinning machine. Got. The pullulan fibers were cut into 5 to 10 cm to obtain short pullulan fibers.

The pullulan short fibers thus obtained are referred to as pullulan fiber B below.

Example 2

The pullulan fiber A obtained in Example 1 was sufficiently dispersed by adding 0.5% of the pullulan fiber A in acetone-water mixture solution at a concentration of 90% and subjected to a papermaking test.

This dispersion was first placed in a long paper vinegar. In other words, this dispersion liquid is flowed onto the wire screen to give vibration and dewatered sufficiently to make the concentration about 9%, and then repeatedly dehydrated by the pressing roller to make the concentration about 39%, followed by drying roller and warm air of 30 ~ 40 ℃. It dried with and obtained the paper of 15% of moisture at 80 degreeC of final temperature.

The paper thus obtained had a thickness of 0.1 mm, was elastic, had a surface similar to that of Japanese paper, was suitable for writing with pens and pencils, and did not seep or smear ink.

Example 3

1 part of wood cellulose pulp was mixed with 2 parts of pullulan fiber A obtained in Example 1, and homogenized by suspension and stirring to 80% concentration in acetone-water solution at 0.3% concentration.

The suspension was treated on a paper machine according to Example 2 and lightly polished with a final calender roller at 80 ° C. The paper thus obtained has a thickness of 0.1 mm and has an elongation of 2.6 in the 1.5 width direction in the longitudinal direction, a breaking strength of 2.5 kg / cm 2-980 in the length direction, and 980 in the width direction, and excellent folding strength of 560 in the width direction. It was similar to Japanese paper with strong elasticity and smooth but less gloss.

This paper had good sensitivity of the printing ink and did not bleed or soak ink.

The paper lost its original form within 8 seconds when placed in stationary cold water, forming a suspension of wood pulp.

Example 4

The pullulan fiber B obtained in Example 1 was sprayed with a weight of 1/3 aqueous maltitol solution by weight, and then absorbed for 10 hours. Pure methanol was then suspended 250 times in volume based on the weight of this fiber to form a uniform dispersion.

The suspension obtained by sufficiently dehydrating the suspension in the same manner as in Example 2 was sufficiently dried by ventilation, gradually heated, and then heated to 80 ° C. in a final roller to obtain a paper having 14% moisture. The paper thus obtained was relatively elastic and had a thickness of 0.08 mm and showed superiority of 630 folding strength and burst strength of 2.1 kg / cm 2 in the length direction of 1,150 in the longitudinal direction.

In addition, this paper was dissolved in water very quickly. A small bag containing a cup of cocoa powder was made of this paper, put into 130cc of hot water, and the water was agitated. Soon, the small bag was dispersed to make a cocoa-free liquid. There was.

Example 5

As in Example 1, 1 part of wood pulp is mixed with 1 part of pullulan fiber B, and the mixed fibers are suspended in 150 parts of 90% isopropyl alcohol solution and homogenized, and the homogenized suspension is hanged on a paper machine at 55 to 90 ° C. The same papermaking treatment as in Example 2 was conducted except that the roller was dried with a drying roller and passed lightly between the calender rollers. The resulting paper was relatively bulky but became a resilient paper with a low fluff and a smooth surface.

When immersed in water, the paper swells and collapses easily. When printing or writing, the paper shows excellent ink sensitivity and is printed smoothly, or becomes ink-free writing.

Example 6

The dried pullulan mass was sprayed with 80% aqueous maltitol solution based on weight by weight of 20% by weight with respect to pullulan and left overnight.

This mass was then heated and extruded to 120 ° C. in a jetting machine to produce pullulan fibers.

The fibers thus produced were cut into lengths of 8 to 10 cm, and the pullulan short fibers thus obtained were subjected to papermaking treatment as in Example 4 to obtain paper having a high folding strength.

Claims (1)

A method for producing paper mainly based on pullulan fibers, wherein the suspension is made by adding plant fibers to pullulan fibers.