JP2004263321A - Method for reinforcing paper and treating solution therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reinforcing paper, with which deteriorated paper data are surely reinforced and which has no fear of unpredictably damaging paper data even in a long-term view point and to obtain a treating solution therefor. <P>SOLUTION: A cellulose derivative is dissolved or dispersed into an organic solvent to give a solution or a dispersion, which is used as the treating solution for reinforcing paper. The treating solution is sprayed on paper by a spraying machine. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology for preserving paper materials, and more particularly, to an enhancement technology for improving the strength of paper materials that are weakened due to deterioration or can be weakened in the future.
[0002]
[Prior art]
Today, the rapid deterioration of paper materials, especially those made of paper mass-produced by technological innovation in the mid-19th century, has become a worldwide problem. This deterioration of the paper material is due to the acidification of the paper. In the past, in the paper manufacturing process, aluminum sulfate was used to fix the sizing agent, which is an ink bleeding agent, on the paper.However, this aluminum sulfate reacts with moisture in the air to generate an acid, It is responsible for the acidification of paper today. Acidification of paper causes damage to the cellulose constituting the fibers of the paper, and breaks the connection between the fibers, resulting in a great decrease in the strength of the paper.
[0003]
For this reason, a method for producing paper without using aluminum sulfate, which causes oxidation, has been developed and put to practical use today. However, there are still many paper materials made of acidified paper (acid paper) in libraries and museums, and these include many valuable materials to be preserved. If these paper materials made of acidic paper are left as they are, they will eventually become tattered and unusable, and it is a very important issue how to suppress the deterioration of existing paper materials.
[0004]
Various solutions have been proposed for such problems. For example, Patent Document 1 discloses that by applying an aqueous solution of sodium silicate to the surface of an acidic paper using a roller, the pH of the acidic paper is adjusted to enable long-term storage.
Further, Patent Document 2 discloses that a thermoplastic polymer substance is dissolved in an organic solvent to prepare a liquid I, and a small amount of water is added to sodium hydroxide, the mixture is heated, and then a nonionic surfactant is added. Liquid II is prepared, liquid I is added to liquid II, and after stirring, magnesium oxide is added and homogenized to prepare liquid III. This liquid III is brushed, dipped, sprayed or the like to obtain an acidic paper. It is disclosed that the acidic paper is reinforced by a thermoplastic polymer substance by applying the acidic paper, and the pH of the acidic paper is adjusted by magnesium oxide as a neutralizing agent.
[0005]
[Patent Document 1]
JP-A-5-265245 [Patent Document 2]
Japanese Patent Application Laid-Open No. 10-46497
[Problems to be solved by the invention]
In the method of applying using a roller or a brush as disclosed in Patent Literature 1, the target is limited to each leaf material, and it is not possible to handle a book-like material. In addition, the aqueous solution not only takes a long time to dry, but also causes damage such as waving on the coated material. Further, in this method, although the deterioration of the material can be suppressed by adjusting the pH, the deteriorated material cannot be strengthened.
[0007]
On the other hand, according to the technology disclosed in Patent Literature 2, since the treatment liquid (liquid III) contains a reinforcing agent in addition to the neutralizing agent, it is possible to simultaneously strengthen and neutralize the paper material. In addition, since the reinforcing agent is not dissolved in an aqueous solution but is dissolved in an organic solvent and used, there is an advantage not found in the technology of Patent Document 1 that drying can be performed quickly and waving after drying can be prevented. Sprays are also mentioned as an application means, whereby a large amount of materials can be applied within a certain period of time, and booklet materials can be handled.
[0008]
However, the thermoplastic polymer substance (hot melt) used as a reinforcing agent in the technique of Patent Document 2 is different from the paper fibers constituting the paper material, and may not be compatible with the paper fibers. Also, in the long run, the deterioration of hot melt may cause new unpredictable damage to paper materials at present. Further, in the technique of Patent Document 2, since a surfactant is added in the process of producing the treatment liquid, substances other than the toughening agent and the neutralizing agent are left on the paper material after the treatment, which also has an effect. There is concern.
[0009]
The present invention has been made in view of such a problem, and it is possible to reliably strengthen a deteriorated paper material, and furthermore, there is no possibility of causing unpredictable damage to the paper material even in a long term. It is an object of the present invention to provide a strengthening method and a processing solution therefor.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a solution or dispersion obtained by dissolving or dispersing a cellulose derivative in an organic solvent is used as a treatment liquid for strengthening paper. Then, the processing liquid is sprayed onto the paper to be processed by the sprayer.
In the present invention, the cellulose derivative serves as a paper reinforcing agent. The cellulose derivative is obtained by introducing a substituent into cellulose, and is characterized by having excellent solubility in an organic solvent or water. Therefore, if the cellulose derivative is soluble in an organic solvent, the cellulose derivative is dissolved in the organic solvent as it is to form a solution, and if the cellulose derivative is soluble only in water, the cellulose derivative is dissolved in water and then added to the organic solvent and strongly stirred. To give a dispersion, and applying the solution or the dispersion to paper enables the cellulose derivative to adhere to the paper fiber surface. Since the paper fiber contains cellulose as a main component, the use of a cellulose derivative as a reinforcing agent allows the paper fiber to be well adapted to the paper fiber. While the technique of Patent Document 2 is to coat paper fibers with a foreign thermoplastic polymer material, the present invention provides a connection between paper fibers cut by deterioration due to cellulose having a chemical structure similar to that of paper fibers. It is reconnected by the derivative. In this way, by using a cellulose derivative having a chemical structure similar to that of paper fiber, the strength of the paper is degraded again due to the deterioration of the paper, or a new damage that cannot be predicted at present due to the deterioration of the paper. Can be prevented from being given.
[0011]
In addition, by using a sprayer as the application means as described above, regardless of whether the paper material to be processed is a leaf-like or a booklet-like, the cellulose derivative as a reinforcing agent is uniformly applied to the paper in a short time. Can be applied to the surface. Further, since an organic solvent is used as the solvent, the drying time can be shortened, measures can be taken efficiently, and waviness accompanying drying can be prevented.
[0012]
If the paper material is acidic paper, the strength of the paper material decreases again over time, even if the strength is temporarily strengthened by the reinforcing agent, because the effect of the acid still remains. I will. Therefore, when an acidic paper is to be processed, it is preferable to use an acidic paper to which an acidic neutralizing agent is added in the above-described processing liquid. According to this, the pH of the paper material is adjusted to be neutral by the acidic neutralizing agent, and further deterioration of the paper material can be suppressed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
In the present invention, a solution or dispersion obtained by dissolving or dispersing a cellulose derivative as a reinforcing agent in an organic solvent is used as a treatment liquid for reinforcing paper. Examples of the cellulose derivative that can be used in the present invention include carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxypropyl cellulose (HPC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (HEMC), and methyl hydroxyethyl cellulose. (MHEC), methylhydroxypropylcellulose (MHPC), ethylhydroxyethylcellulose (EHEC) and the like, but are not limited thereto. Among them, carboxymethylcellulose (CMC), methylcellulose (MC), hydroxypropylcellulose (HPC), and ethylcellulose (EC) are particularly preferable in that they are easily dissolved or dispersed in an organic solvent and have a high reinforcing effect.
[0014]
Among these cellulose derivatives, those soluble in an organic solvent are directly dissolved in an organic solvent and used as a solution. On the other hand, those which are insoluble in an organic solvent but soluble in water are dissolved in water and then added to the organic solvent. When the solubility of the cellulose derivative in an organic solvent or water changes depending on the temperature, the cellulose derivative may be dissolved while appropriately heating according to the temperature characteristics. The amount of the cellulose derivative to be added to the organic solvent or water is preferably such that the cellulose derivative is completely dissolved in the organic solvent or water. However, even if the undissolved cellulose derivative remains, the amount is very small. As long as there is no problem.
[0015]
Examples of the organic solvent for dissolving or dispersing the cellulose derivative include, but are not limited to, methyl alcohol, ethyl alcohol, butyl alcohol, isopropyl alcohol, benzene, toluene, xylene, ethyl acetate, butyl acetate, and acetone. The selection criteria for the organic solvent include the solubility of the cellulose derivative to be added, the ease of handling, the influence on paper materials and the environment, and of course, other criteria can also be used. Among the organic solvents listed above, alcohol solvents such as methyl alcohol and ethyl alcohol are particularly preferable. Alcohol has a relatively high degree of safety for the human body among organic solvents, and is easy to handle when applied using an air gun as described later.
[0016]
In the present invention, it is also possible to add an acid neutralizing agent to the treatment liquid, which is preferable for controlling the pH of the acidified paper material to suppress deterioration. Examples of the acidic neutralizing agent that can be added to the treatment liquid include, but are not limited to, basic substances such as magnesium carbonate, calcium carbonate, magnesium oxide, and calcium oxide. These acidic neutralizing agents are dispersed in a small amount of water and then added to an organic solvent and mixed with stirring, or added in the form of powder into the organic solvent and mixed with stirring. The amount of the acid neutralizing agent to be added may be determined according to the degree of acidification of the paper material to be treated. The selection criteria for the acidic neutralizing agent include neutralizing ability, influence on paper materials and the environment, and of course, it is also possible to select based on other criteria. In the treatment liquid of the present invention, it is not always essential to add an acidic neutralizing agent. For example, it is not necessary to add an acid neutralizing agent if the paper is to be used for strengthening paper whose strength has been simply reduced by use, not due to acidification.
[0017]
In the present invention, the above-described treatment liquid is applied to the surface of paper to strengthen the deteriorated paper. As a coating method, a method of applying one by one with a roller or a brush, or a method of applying to a large number of papers at once by a jetting device such as dough pickling or an air gun can be used. The application method is adopted. According to the ejector, the processing liquid can be uniformly applied in a short time regardless of whether the paper material is leaf-shaped or booklet-shaped, and a large amount of paper material can be processed in a short time in combination with the quick drying property of the organic solvent. It becomes possible.
[0018]
【Example】
Hereinafter, more specific examples of the method for strengthening paper of the present invention and the processing solution for the same, confirmed by the present inventors, will be described.
[0019]
(1) Preparation of treatment liquids First, the following four treatment liquids were prepared using different cellulose derivatives as treatment liquids for strengthening paper. Note that methanol was used as an organic solvent, and magnesium carbonate was used as an acidic neutralizing agent.
[0020]
(1-1) Carboxymethyl cellulose (CMC: manufactured by Daicel Chemical Industries, Ltd., trade name: 1130, water content: 6.6%, 1% viscosity: 76 mPA · s, pH = 6.8, ether: The conversion degree was 0.68). First, 500 ml of distilled water heated to about 80 ° C. was placed in a beaker, and 25 g of CMC weighed accurately was gradually added, followed by gentle stirring. After confirming that CMC was completely dissolved in water, the whole was adjusted to 500 g and left in the refrigerator all day long.
[0021]
Next, 100 g of the gelled CMC and 5 g of magnesium carbonate as an acidic neutralizing agent were taken, put into 275 g of methanol as an organic solvent, and dispersed by vigorous stirring. After confirming the dispersion state, the mixture was transferred to a container and methanol was added until the amount became 400 g. As a result, a treatment liquid 1 having a solution water content of 23.8 w% and a solution CMC content of 1.25 w% was prepared. The solution was drastically reduced by vaporization, so that the solution was placed in a sealable plastic container and subjected to an immediate application test. When the solution was applied several times, the gelled CMC was taken and the solution was adjusted each time.
[0022]
(1-2) Methyl cellulose (MC: manufactured by Shin-Etsu Chemical Co., Ltd., trade name: SM-100, moisture: 2.9%, 2% viscosity: 102 mPA · s, methoxyl group 29.4) as a prepared cellulose derivative of the treatment liquid 2 Was used. First, 500 ml of distilled water heated at about 80 ° C. was placed in a beaker, and 25 g of accurately weighed MC was gradually added thereto, followed by gentle stirring. After confirming that the MC was completely dissolved in the water, the whole was adjusted to 500 g and left in the refrigerator all day and night.
[0023]
Next, 100 g of MC and 5 g of magnesium carbonate as an acidic neutralizing agent were taken, put into 275 g of methanol as an organic solvent, and dispersed by vigorous stirring. After confirming the dispersion state, the mixture was transferred to a container and methanol was added until the amount became 400 g. As a result, a treatment liquid 2 having a solution water content of 23.8 w% and a solution MC rate of 1.25 w% was prepared. The solution was drastically reduced by vaporization, so that the solution was placed in a sealable plastic container and subjected to an immediate application test. When the solution was applied a number of times, the gelled MC was taken each time to adjust the solution.
[0024]
(1-3) Hydroxypropylcellulose (HPC: manufactured by Aqualon, trade name Klucel E. Low viscosity type) was used as the prepared cellulose derivative of the treatment liquid 3. First, 400 g of methanol as an organic solvent was placed in a sealable reagent bottle, and stirred with a magnetic stirrer (about 800 rpm). Then, 10 g of HPC (Klucel E) was gradually added, and after confirming complete dissolution, 10 g of magnesium carbonate as an acidic neutralizing agent dissolved in 40 g of water was added. After becoming homogeneous, an isopropyl alcohol solution was added until the amount became 800 g. As a result, a treatment liquid 3 having a solution water content of 5.0 w% and a solution HPC ratio of 1.25 w% was prepared. The solution was drastically reduced by vaporization, so that the solution was placed in a sealable plastic container and subjected to an immediate application test. Excess solution was discarded and a new solution was prepared each time.
[0025]
(1-4) Hydroxypropylcellulose (HPC: manufactured by Aqualon, trade name Klucel G. Medium viscosity type) was used as the prepared cellulose derivative of the treatment liquid 4. First, 400 g of methanol as an organic solvent was placed in a sealable reagent bottle, and stirred with a magnetic stirrer (about 800 rpm). Then, 10 g of HPC (Klucel G) was gradually added, and after confirming complete dissolution, 10 g of magnesium carbonate as an acidic neutralizing agent dissolved in 40 g of water was added. After becoming homogeneous, an isopropyl alcohol solution was added until the amount became 800 g. As a result, a treatment liquid 4 having a solution moisture content of 10.0 w% and a solution HPC ratio of 1.25 w% was prepared. The solution was drastically reduced by vaporization, so that the solution was placed in a sealable plastic container and subjected to an immediate application test. Excess solution was discarded and a new solution was prepared each time.
[0026]
(2) Coating process The coating process employs a batch process in which a processing solution is sprayed on a plurality of sheets of paper at once, and as shown in FIG. 1, four sheets of paper (washed paper, Maruzumi Paper Co., Ltd.) are placed on a white board. Manufactured, trade name, etc., pH = 5.8) was placed, and a magnet sheet was attached by overlapping about 5 mm to fix the paper. Then, a method was employed in which an air gun as an injector was attached to the compressor (5 to 7 atm) and the treatment liquid was sprayed on the surface of the paper. The nozzle of the air gun was set to the finest mist. The spraying was performed while moving the nozzle as shown by an arrow in FIG. 1 from a distance of about 30 to 50 cm so that the treatment liquid was uniformly applied to the paper. After the spraying of the paper on the front side was completed, the processing liquid was sprayed on the back side of the paper in the same procedure by turning the paper upside down, and the processing liquid was sprayed twice on each of the front and back sides by repeating this. .
[0027]
(3) The drying and drying were natural drying on the spot. Alcohol, which is a solvent, evaporates immediately after coating, so that drying was actually quick, and drying was possible instantaneously. As a result, it was confirmed that a large amount of paper materials could be processed in a short time.
[0028]
(4) Confirmation of Coating Amount The four sheets of the batch-processed paper were incinerated in an electric furnace (450 ° C.). The residue increment due to incineration is magnesium carbonate. In each treatment liquid, the w% of the cellulose derivative and the w% of the magnesium carbonate are prepared so as to be the same amount. Therefore, the amount of magnesium carbonate of each paper is the amount of the reinforcing agent (cellulose derivative) applied to each paper. Means
[0029]
(5) pH Measurement The pH measurement was performed on the test paper coated with each of the treatment liquids 1 to 4 and on the test paper not treated at all, immediately after the treatment and after the accelerated deterioration treatment according to ISO5630-4. . The result is shown in FIG.
As shown in FIG. 2, immediately after the treatment (the number of days of deterioration in the figure is 0), the surface pH of the test paper coated with any of the treatment liquids 1 to 4 is higher than the surface pH of the untreated test paper. It was confirmed that. This indicates that deacidification is effectively performed by magnesium carbonate, which is an acidic neutralizing agent. Also, after the accelerated aging treatment (5, 10, 20 days of deterioration in the figure), the surface pH of the test paper coated with any of the treatment liquids 1 to 4 exceeds the surface pH of the untreated test paper. This confirmed the persistence of the deacidification.
[0030]
(6) Tearing test A tear test was performed to guide the degree of deterioration (degree of reinforcement) of the paper material. The tear test was performed on the test paper coated with each of the treatment liquids 1 to 4 and on the test paper not treated at all, immediately after the treatment and after the accelerated deterioration treatment according to ISO5630-4. The result is shown in FIG.
[0031]
As shown in FIG. 3, immediately after the treatment (the number of days of deterioration in the figure is 0), the tear strength of the test paper coated with any of the treatment liquids 1 to 4 exceeds the tear strength of the untreated test paper. It was confirmed that the paper was effectively strengthened. Also, after the accelerated aging treatment (5, 10, 20 days of deterioration in the figure), the tear strength of the test paper to which any of the treatment liquids 1 to 4 was applied was the same as the tear strength of the untreated test paper. This confirms the permanence of the reinforcing effect.
[0032]
(7) Tensile test Further, a tensile test was performed. The tensile test was performed on the test paper coated with each of the treatment liquids 1 to 4 and on the test paper without any treatment, immediately after the treatment and after the accelerated deterioration treatment according to ISO5630-4. The result is shown in FIG.
As shown in FIG. 4, immediately after the treatment (day 0 in the figure), the tear strength of the test paper coated with the treatment liquids 1, 2, and 4 exceeded the tensile strength of the untreated test paper. Further, after the accelerated deterioration treatment (day 20 in the figure), the tensile strength of the test paper coated with any of the treatment liquids 1 to 4 exceeded the tensile strength of the untreated test paper. From this, it was confirmed that the paper was effectively strengthened and the effect was permanent, as a whole.
[0033]
【The invention's effect】
As described above in detail, according to the present invention, by using a cellulose derivative as a reinforcing agent, cellulose fibers weakened by deterioration and bonds between the fibers are reinforced by a cellulose derivative having a chemical structure similar to that of paper fibers. Thus, the degraded paper material can be reliably strengthened without causing new damage that cannot be predicted at present. In addition, by using an organic solvent as the solvent, the drying time can be shortened, measures can be taken efficiently, and the ripples associated with the drying can be prevented. Furthermore, by using a sprayer as the application means, regardless of whether the paper material to be processed is leaf-shaped or booklet-shaped, the cellulose derivative as a reinforcing agent is uniformly applied to the paper surface in a short time. can do.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a method of applying a treatment liquid according to an embodiment of the present invention.
FIG. 2 is a graph showing a measurement result of pH measurement in an example of the present invention.
FIG. 3 is a graph showing a test result of a tear test in an example of the present invention.
FIG. 4 is a graph showing a test result of a tensile test in an example of the present invention.

Claims (4)

A method for strengthening paper, comprising spraying a treatment liquid obtained by dissolving or dispersing a cellulose derivative in an organic solvent onto an object to be treated by an injector. The method for strengthening paper according to claim 1, wherein the treatment liquid to which an acidic neutralizing agent is added is used. A treatment liquid for strengthening paper, which is obtained by dissolving or dispersing a cellulose derivative in an organic solvent. The processing solution for strengthening paper according to claim 3, further comprising an acidic neutralizing agent.

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