CN110318296B

CN110318296B - Paper deacidification agent based on alkyl ketene dimer modified magnesium hydroxide and preparation method thereof

Info

Publication number: CN110318296B
Application number: CN201910518397.6A
Authority: CN
Inventors: 张涛
Original assignee: Hubei Taide Anxin Information Technology Co ltd
Current assignee: Hubei Taide Anxin Information Technology Co ltd
Priority date: 2019-06-15
Filing date: 2019-06-15
Publication date: 2021-08-03
Anticipated expiration: 2039-06-15
Also published as: CN110318296A

Abstract

The invention relates to a deacidification agent based on alkyl ketene dimer modified magnesium hydroxide and a preparation method thereof. Firstly, adding magnesium hydroxide into molten alkyl ketene dimer for modification, and then dispersing the modified magnesium hydroxide into a mixed solvent of perfluoroheptane and petroleum ether to obtain the target deacidification agent. The deacidification agent has the advantages of easily obtained raw materials, mild reaction conditions, simple and convenient preparation and use methods, small dosage, high efficiency, good deacidification effect and uniformity.

Description

Paper deacidification agent based on alkyl ketene dimer modified magnesium hydroxide and preparation method thereof

Technical Field

The invention relates to the technical field of book and archive treatment and chemical compositions, in particular to a paper deacidification agent based on alkyl ketene dimer modified magnesium hydroxide and a preparation method thereof.

Background

At present, in various libraries, museums and file organizations in China, tens of thousands of precious books, calligraphy and painting, newspapers, files and other cultural heritages which are left over all the time are kept, wherein most of the cultural heritages are written and printed by handmade paper or mechanical paper. With the passing of time, the phenomena of yellowing, mildew, pulverization, fragmentation and the like of paper documents gradually occur, which are mainly caused by acidification of paper. The deterioration of the paper material is macroscopically manifested as discoloration and microscopically is the structural damage (reduction in mechanical strength).

Cellulose is a main component of paper, which is quite stable under neutral and weakly alkaline conditions, not only is difficult to hydrolyze and oxidize, but also the hydrolysis rate increases proportionally with the increase in hydrogen ion concentration, i.e., the lower the pH, the faster the hydrolysis rate of cellulose, which is stronger in acidity. The degree of polymerization decreases after hydrolysis of the cellulose, resulting in a consequent decrease in the strength of the paper material, with the consequent deterioration and embrittlement of the paper as a result.

The acid in paper is from many sources, including sulfite, alum and other substances added in the paper making process, acid gas increased gradually due to industrial development, and acid substances brought by external microorganisms, mold and the like. These different routes of acidic substances are responsible for the acid deterioration of paper documents.

The deacidification technology of the paper literature widely applied at present mainly comprises the following steps: the method comprises a solution method and a gas phase method, wherein the gas phase method has the defects of relatively complex process, vacuum matching, long treatment period, relatively expensive equipment and the like; the solution method is divided into a water system and an organic system, and the deacidification agent used in the water system solution method can cause paper wrinkles, adhesion, fading and the like. The use of organic solutions is therefore more advantageous in deacidification of paper. The deacidification agent used in the process typically comprises a metal oxide or hydroxide (e.g., magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, etc.) and an organic solvent (fluoroalkane). However, since the polarity of the fluoroalkane is very small, the dispersibility of the magnesium hydroxide, magnesium oxide and the like in the fluoroalkane is very poor, so that the improvement of the dispersibility of the deacidification substance in the organic solvent is a key factor for improving the efficiency of the deacidification agent.

Disclosure of Invention

The invention aims to overcome the various problems of the existing paper deacidification agent and provides the deacidification agent with simple preparation process, convenient use and good effect, and the preparation method comprises the following steps:

heating alkyl ketene dimer to completely melt the alkyl ketene dimer, adding magnesium hydroxide into the molten liquid in proportion, stirring for reaction, separating to obtain modified magnesium hydroxide, and dispersing the modified magnesium hydroxide in a mixed solvent composed of perfluoroheptane and petroleum ether.

Furthermore, the mass ratio of the magnesium hydroxide to the alkyl ketene dimer is 0.5-5: 1-10.

Further, the alkyl ketene dimer is heated to above 110 ℃ to completely melt the alkyl ketene dimer.

Further, adding magnesium hydroxide, keeping the temperature of 95-130 ℃, stirring, reacting for more than 30min, then carrying out suction filtration while the mixture is hot, then washing by adopting an alcohol solvent at the temperature of 60-75 ℃, and drying for 18-36h at the temperature of 30-45 ℃ after washing is finished to obtain the modified magnesium hydroxide.

Further, the alcohol solvent is specifically absolute ethyl alcohol.

Further, the mass ratio of the perfluoroheptane to the petroleum ether in the mixed solvent is 1530-1615: 32-66.

Further, the mass ratio of the modified magnesium hydroxide to the mixed solvent is 0.05-1: 100.

Further, the modified magnesium hydroxide is uniformly dispersed in the mixed solvent through homogenization and ultrasonic treatment.

Another object of the present invention is to provide a deacidification agent prepared by the above method.

Alkyl ketene dimer is a sizing agent that can be used by itself for paper repair. The modification of magnesium hydroxide by alkyl ketene dimer can reduce the surface activation energy of magnesium hydroxide, enhance the compatibility of magnesium hydroxide and organic solvent, and is beneficial to improving the dispersion of magnesium hydroxide in perfluoroheptane. The method adopts the excessive molten alkyl ketene dimer as a dispersion medium, so that the magnesium hydroxide can be fully contacted with the modifier, and the modification rate of the magnesium hydroxide is improved. The polarity of the perfluoroheptane is very low, and petroleum ether with similar polarity mutually soluble with the perfluoroheptane is used as a solubilizer, so that the dispersibility of the modified magnesium hydroxide in the perfluoroheptane can be improved.

Compared with the prior art, the invention has the following beneficial effects: the raw materials are easy to obtain, the reaction condition is mild, the preparation and use methods are simple and convenient, the adoption of complex and expensive vacuum equipment is avoided, and the cost is reduced; the composite organic solvent system is adopted, so that the adverse effect of the deacidification process on the paper is reduced; the deacidification agent has the advantages of less dosage, high efficiency, good deacidification effect and uniformity.

Drawings

FIG. 1 is a transmission electron micrograph of magnesium hydroxide before and after treatment according to the modification method of example 1 of the present invention.

FIG. 2 is an electron micrograph of a paper document before and after treatment with the deacidification agent prepared in example 1 of the present invention.

Detailed Description

In order to make those skilled in the art fully understand the technical solutions and advantages of the present invention, the following embodiments are further described.

Example 1

2g of alkyl ketene dimer was heated to about 110 ℃ to completely melt it, and 2g of magnesium hydroxide was added and stirred at this temperature for 30 min. And after the reaction is finished, carrying out suction filtration while the reaction is hot, repeatedly washing the filter cake by using hot ethanol with the temperature of 75 ℃ of about 100mL for many times, and finally drying the filter cake in a vacuum environment at the temperature of 35 ℃ for 24 hours to obtain the modified magnesium hydroxide.

1600g of perfluoroheptane and 32g of petroleum ether are mixed and stirred uniformly to obtain a mixed solvent. Adding 2g of dried modified magnesium hydroxide into the mixed solvent, transferring the obtained mixture into a homogenizer for homogenizing for 8min under the condition of 8000r/min, and then carrying out ultrasonic treatment for 30min to obtain the deacidification agent.

Example 2

1.6g of alkyl ketene dimer was heated to 110 ℃ to completely melt it, and 1.6g of magnesium hydroxide was added and stirred at this temperature for 30 min. And after the reaction is finished, performing suction filtration, repeatedly washing the filter cake for multiple times by using hot ethanol with the total volume of about 50mL and the temperature of 75 ℃, and finally drying the filter cake in a vacuum environment at the temperature of 35 ℃ for 24 hours to obtain the modified magnesium hydroxide.

1615g of perfluoroheptane and 38g of petroleum ether are mixed and stirred uniformly to obtain a mixed solvent. Adding 1.5g of dried modified magnesium hydroxide into the mixed solvent, transferring the obtained mixture into a homogenizer for homogenizing for 8min under the condition of 8000r/min, and then carrying out ultrasonic treatment for 30min to obtain the deacidification agent.

Comparative example 1

Putting magnesium hydroxide powder in an environment of 35 ℃ for vacuum drying for 24h, then directly mixing magnesium hydroxide and perfluoroheptane in a ratio of 1:800, transferring the obtained mixture into a homogenizer for homogenizing for 8min under the condition of 8000r/min, and then carrying out ultrasonic treatment for 30min to obtain the deacidification agent.

Comparative example 2

Comparative example 2 is substantially the same as comparative example 1 except that: the magnesium hydroxide, the perfluoroheptane and the petroleum ether are directly mixed according to the proportion of 1:800: 40.

Comparative example 3

Comparative example 3 is substantially the same as comparative example 1 except that: the magnesium hydroxide, the perfluoroheptane and the alkyl ketene dimer are directly mixed in a ratio of 1:800: 0.2.

Paper documents were subjected to a soaking deacidification treatment (soaking time 3min) at room temperature using the deacidification agents prepared in examples 1 and 2 and comparative examples 1 to 3, and then taken out to be air-dried, and the paper properties after the deacidification treatment were measured as shown in table 1 below.

TABLE 1 Deacidification Effect of different deacidification agents

The transmission electron microscope analysis of magnesium hydroxide before and after modification in example 1 showed the results shown in FIG. 1 (left before modification and right after modification). As can be seen from FIG. 1, the modified magnesium hydroxide has a coating on its surface, which indicates that the modified alkyl ketene dimer is coated on the magnesium hydroxide surface to facilitate the dispersion of magnesium hydroxide in perfluoroheptane.

The paper document was subjected to a soaking deacidification treatment at room temperature using the deacidification agent prepared in example 1 (soaking time 3min), then taken out and air-dried, and the microstructure changes before and after deacidification treatment of the paper document were analyzed by a scanning electron microscope, and the results are shown in fig. 2 (left before deacidification and right after deacidification). As can be seen from fig. 2, a large number of solid particles are attached to the surface of the paper fiber after the deacidification treatment, and the structure of the solid particles is substantially consistent with that of the nano-magnesia, which indicates that the magnesia particles are attached to the surface of the paper fiber to achieve the deacidification effect.

The influence of the soaking time on the deacidification effect was examined by using the deacidification agent obtained in example 1 in the same manner, and the results are shown in table 2.

TABLE 2 influence of soaking time on deacidification Effect

The above experimental results show that: the soaking time is too short (below 1 min), the adhesion amount of the deacidification agent on the surface of the paper is less, and the paper acidity treatment is not obvious; the soaking time is too long (more than 5 min), the pH value is not obviously increased, and the appearance of obvious white accumulation on the surface of the paper can be observed macroscopically, which can influence the basic physical properties of the paper. The moderate soaking time can ensure the deacidification effect of the paper to be obvious and the physical performance of the paper to be basically unchanged, the micro deacidification agent has enough adhesion on the paper and the macro paper has no obvious white accumulation on the surface, so the soaking time is controlled to be 1-5 min. The experiment also shows that the short-time soaking treatment of the perfluoroheptane-petroleum ether composite solvent system has little influence on the basic performances of paper, such as brittleness and the like.

Similar effects were obtained by conducting the above experiment using the deacidification agent obtained in example 2.

Claims

1. The preparation method of the paper deacidification agent based on the alkyl ketene dimer modified magnesium hydroxide is characterized by comprising the following steps: heating the alkyl ketene dimer to completely melt the alkyl ketene dimer, then adding magnesium hydroxide into the molten liquid in proportion, stirring for reaction, and separating to obtain modified magnesium hydroxide; dispersing modified magnesium hydroxide in a mixed solvent consisting of perfluoroheptane and petroleum ether, wherein the mass ratio of the perfluoroheptane to the petroleum ether in the mixed solvent is 1530-1615:32-66, and the mass ratio of the modified magnesium hydroxide to the mixed solvent is 0.05-1: 100.

2. The method of claim 1, wherein: the mass ratio of the magnesium hydroxide to the alkyl ketene dimer is 0.5-5: 1-10.

3. The method of claim 1, wherein: the alkyl ketene dimer is heated to above 110 ℃ to completely melt the alkyl ketene dimer.

4. The method of claim 1, wherein: adding magnesium hydroxide, keeping the temperature at 95-130 ℃, stirring, reacting for more than 30min, then carrying out suction filtration while the mixture is hot, then washing by adopting an alcohol solvent at 60-75 ℃, and drying for 18-36h at 30-45 ℃ after washing is finished to obtain the modified magnesium hydroxide.

5. The method of claim 4, wherein: the alcohol solvent is specifically absolute ethyl alcohol.

6. The method of claim 1, wherein: the modified magnesium hydroxide is uniformly dispersed in the mixed solvent through homogenization and ultrasonic treatment.

7. A paper deacidification agent based on alkyl ketene dimer modified magnesium hydroxide, characterized in that the deacidification agent is prepared according to any one of the method of claims 1-6.