KR20010056213A - Process for preparing paper having good strength, dimensional stability and antibacterial property - Google Patents

Abstract

PURPOSE: A process for preparing the titled paper by surface treatment of paper with chitosan-containing polyvinyl alcohol or a starch solution is provided. Whereby, the obtained paper has excellent physical properties, strength, dimensional stability and antimicrobial properties as compared to conventional paper treated with polyvinyl alcohol or starch alone. CONSTITUTION: Paper is surface-treated with chitosan-containing polyvinyl alcohol or a starch solution or the surface treated paper is optionally treated with an aqueous solution containing 1 to 2% by weight of a boron aqueous solution or 1 to 2% by weight of boron and 2 to 20% by weight of glycerin to produce the titled paper. The chitosan-containing polyvinyl alcohol or a starch solution is prepared by mixing 0.1 to 5% by weight of a mixed solution of chitosan, water and 0.2 to 2% by weight of an aqueous solution of acetic acid with 2 to 5% by weight of an aqueous solution of polyvinyl alcohol or 2 to 30% by weight of a starch solution in a weight ratio of 1:99 to 50:50.

Description

PROCESS FOR PREPARING PAPER HAVING GOOD STRENGTH, DIMENSIONAL STABILITY AND ANTIBACTERIAL PROPERTY}

The present invention relates to a method for producing a paper excellent in strength, dimensional stability and antibacterial properties.

Conventionally, polyvinyl alcohol, gelatin, starch and the like have been used as surface treatment agents to increase the surface strength, paper strength and printability of paper. However, the surface treated with polyvinyl alcohol, gelatin or starch alone has the disadvantages of poor dimensional stability and low strength properties, and the disadvantage of being damaged by bacteria or mold due to the lack of antibacterial properties, so it is a security paper such as securities. It was insufficient to use. For example, banknotes, a kind of oil price increase, are exchanged among a myriad of users and are exposed to many germs in the process, which may adversely affect the user's health. In addition, the dimensional stability of paper is very important for securities undergoing a high-precision printing process. When the paper is surface-treated by conventional methods using polyvinyl alcohol, gelatin or starch alone, the dimensional stability of the paper is poor.

U.S. Patent No. 4,056,432 discloses a method of adding chitosan, a polymer, to a paper for making paper using a mixture of graft copolymers of acrylic or diaryl monomers for the purpose of improving the dry strength of the paper. U.S. Patent No. 4,102,738 also discloses a method of adding chitosan dissolved in an acidic solution to improve the strength of corrugated cardboard. U. S. Patent No. 5,454, 907 discloses a method of adding sulfonic acid and chitosan upon refining for the purpose of increasing the refining efficiency of the pulp fibers and improving their strength. U. S. Patent No. 5,827, 610 also discloses a process for making paper by coating chitosan on aramid fibers for the purpose of increasing the coefficient of friction of the paper.

On the other hand, Japanese Patent No. 2,127,596 discloses a method of manufacturing an antimicrobial paper by treating a low molecular weight chitosan to a paper, but the paper produced by this method has a disadvantage of low strength by using a low molecular weight chitosan.

Accordingly, it is an object of the present invention to provide a paper manufacturing method in which the strength, dimensional stability, and antimicrobial properties of the paper are solved at the same time.

In accordance with the above object, the present invention provides a method for producing paper, comprising the step of surface-treating the paper with chitosan-containing polyvinyl alcohol or starch solution.

Hereinafter, the present invention will be described in detail.

In the present invention, after wetland formation, the first dried paper is treated with a surface treatment solution containing polyvinyl alcohol and chitosan or a surface treatment solution containing starch and chitosan. The surface treatment solution is a solution of chitosan having a deacetylation degree of 80 to 95% and a molecular weight of 100,000 to 1,000,000 at a concentration of 0.1 to 5% by weight in water or 0.2 to 2% by weight of acetic acid solution, 2 to 5% by weight It can be prepared by mixing a polyvinyl alcohol aqueous solution or 2 to 30% by weight aqueous solution of starch with a weight ratio of 1:99 to 50:50. Preferably, the chitosan has a deacetylation degree of 90 to 95, a molecular weight of 300,000 to 500,000, a concentration of an aqueous polyvinyl alcohol solution is preferably 3 to 4 wt%, and a concentration of an aqueous starch solution is 10 to 20 wt%. desirable. The polyvinyl alcohol aqueous solution can be obtained by adding polyvinyl alcohol to water and swelling and dissolving it at a temperature of 70 to 99 ° C., and the starch aqueous solution can be obtained by adding starch to water and dissolving at a temperature of 70 to 120 ° C. have.

Chitosan to be used in the method of the present invention is a natural high molecular substance present after cellulose on the earth, and is obtained by deacetylating chitin present in crab shells, shrimps, mushrooms, and fungi. Chitosan has a chemical structure that is very similar to cellulose, so it is very compatible with paper, the main ingredient of which is cellulose, which not only improves the general properties of the paper but also improves the antimicrobial activity.

Polyvinyl alcohol, which can be used as a surface treatment agent with chitosan, was originally used as an adhesive or a surface treatment agent, and when surface-treated on paper, not only improves the surface strength, paper strength, etc. of the paper, but also printability.

In addition, starch that can be used with chitosan has been used as a surface treatment agent in the past.

The surface treated paper may then be dried in accordance with conventional methods to obtain the final product paper. In addition, when surface treatment is performed using polyvinyl alcohol, the surface-treated paper may be post-treated with an aqueous solution of borax or an aqueous solution of borax and glycerin to cure the polyvinyl alcohol. An aqueous solution of% borax is preferable, and an aqueous solution containing 1 to 2% by weight of borax and 2 to 20% by weight of glycerin is preferable as an aqueous solution of borax and glycerin.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example 1

A solution obtained by dissolving chitosan having a molecular weight of 500,000 and 90% deacetylation at a concentration of 1% by weight in a 1% by weight acetic acid solution was mixed with a 4.7% by weight polyvinyl alcohol solution at a weight ratio of 15:85, and 0.15% by weight of chitosan and polyvinyl. A surface treatment solution containing 4% by weight of alcohol was prepared. The solution was placed in a surface treatment tank, and after the formation of the wetland, the first dried paper (cotton pulp) was dipped for 20 seconds, and then pressed using a press roll to remove the surface treatment solution remaining on the surface of the paper. . The primary surface treated paper was impregnated in an aqueous 1.5 wt% borax solution for 5 seconds to cure, followed by hot air drying and drum drying to obtain a final paper.

Example 2

A solution obtained by dissolving chitosan having a molecular weight of 500,000 and 90% deacetylation at a concentration of 1% by weight in a 1% by weight acetic acid aqueous solution was mixed with a 16.7% by weight aqueous starch oxide solution at a weight ratio of 10:90, 0.1% by weight of chitosan and starch oxide 15 A surface treatment solution containing weight percent was prepared. The solution was placed in a surface treatment tank, and after the formation of the wetland, the first dried paper (pulp) was dipped for 20 seconds, and then pressed using a press roll to remove the surface treatment solution remaining on the surface of the paper. The surface treated paper was hot air dried and drum dried to obtain a final paper.

Example 3

The final paper was obtained according to the method of Example 1, except that chitosan having a molecular weight of 100,000 and a deacetylation degree of 95% was used.

Comparative Examples 1 to 3

The paper of Comparative Examples 1 to 3 was prepared by following the method of Examples 1, 2 and 3 except that chitosan was not added.

Test Example

Tensile strength, fracture resistance, bursting strength, internal bonding strength, stretching ratio and antibacterial properties of the papers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were measured according to the following methods.

Tensile Strength: KS M 7014-85

Heat Resistance: KS M 7065-92

Bursting Strength: KS M 7017-85

Internal Bonding Strength: TAPPI UM 403

Stretch rate: The rate of length increase when the paper is measured in wet condition sufficiently after measuring its length under standard humidity conditions.

As a result of the test, the paper produced in Example 1 had a 20% higher tensile strength, 15% higher fracture resistance, 18% higher bursting strength, and 18% higher internal bonding strength than the paper of Comparative Example 1 having polyvinyl alcohol surface treated alone. Aptitude was also good. In addition, in the stretch ratio that can evaluate the dimensional stability of the paper, the paper of Comparative Example 1 was elongated by 5% in the width direction, but only 1.5% of the paper of Example 1 exhibited stability.

In addition, the paper prepared in Example 2 increased 10% tensile strength, 13% fracture resistance, 15% bursting strength, and 17% internal bonding strength, compared to the paper of Comparative Example 2 in which the starch oxide was surface-treated alone, and the printability was also good. It was. In addition, the stretch rate of the paper produced in Comparative Example 2 was 6%, the stretch rate of the paper produced in Example 2 was 2% was excellent in stretch stability.

The paper produced in Example 3 had the same general properties as those of Examples 1 and 2 or more. In addition, in the antibacterial activity against E. coli, the paper of Comparative Example 3 surface treated with oxidized starch alone showed no E. coli reduction rate, whereas the paper produced in Example 3 showed an E. coli reduction rate of 85% or more, which showed good antibacterial activity.

According to the present invention, a paper treated with a surface treatment agent containing chitosan together with polyvinyl alcohol or starch is superior in physical properties, strength and dimensional stability to conventional paper treated with polyvinyl alcohol or starch alone, and has antibacterial properties.

Claims (3)

Surface treatment of the dried paper with chitosan-containing polyvinyl alcohol or starch aqueous solution after the formation of the wetland, the paper manufacturing method. The method of claim 1, 2-5 wt% polyvinyl alcohol in which the aqueous solution was dissolved in chitosan having a deacetylation degree of 80 to 95% and a molecular weight of 100,000 to 1,000,000 at 0.1 to 5 wt% in water or 0.2 to 2 wt% acetic acid solution. It is prepared by mixing with an aqueous solution or 2 to 30% by weight starch aqueous solution in a weight ratio of 1:99 to 50:50. The method of claim 1, Further treating the paper surface-treated with the aqueous chitosan-containing polyvinyl alcohol solution with an aqueous solution containing 1 to 2% by weight of borax or 1 to 2% by weight of borax and 2 to 20% by weight of glycerin. Method comprising a.