Paper deacidification reinforcement microcapsule and preparation method and application thereof

Abstract

The invention belongs to the technical field of restoration and protection of paper cultural relics, and discloses a paper deacidification reinforcement microcapsule and a preparation method and application thereof.The preparation method comprises the steps that 1, a chitosan quaternary ammonium salt solution with the mass concentration being 0.2%-5% and a carboxymethylcellulose solution with the mass concentration being 0.2%-4% are stirred for 1-3 hours at the room temperature, and a chitosan quaternary ammonium salt solution is obtained; a chitosan quaternary ammonium salt-carboxymethyl cellulose solution is obtained; (2) dispersing 0.2-0.8 g of nano calcium carbonate in a 95% ethanol solution, and carrying out ultrasonic cavitation to obtain a calcium carbonate-ethanol suspension; and (3) adding the calcium carbonate-ethanol suspension into the chitosan quaternary ammonium salt-carboxymethyl cellulose solution, and carrying out high-speed shearing emulsification to obtain the deacidified and reinforced microcapsule. The deacidification reinforcing microcapsule is simple and convenient to prepare and use, has a good deacidification reinforcing effect, enables paper to be alkaline and anti-aging after being treated, and can effectively improve the durability and prolong the storage life of the paper.

Description

Technical Field

[0001] The invention belongs to the technical field of restoration and protection of paper cultural relics, in particular to a paper deacidification reinforcement microcapsule and a preparation method and application thereof. Background Art

[0002] Paper is an important carrier of culture, with great historical, cultural and research value, and plays an important role in our study of the history of a certain era. However, as time goes by, paper documents are affected by various factors, including storage environment and production process. A large number of paper documents have acidified to varying degrees, which causes a series of problems such as yellowing and brittleness, reducing the service life of paper documents and eventually making them unreadable. At present, at least 1 / 3 of the paper documents stored in the world have been acidified. Therefore, it is very important to deacidify and reinforce paper documents.

[0003] Paper acidification is an important factor affecting the life of paper. The main component of paper is cellulose. Under acidic conditions, cellulose will hydrolyze, resulting in a decrease in the degree of polymerization of cellulose, and ultimately reduce the strength of paper. At present, the best way to solve the acidification of paper is deacidification, which neutralizes the free acid in the paper by applying alkaline substances to the paper, and keeps the paper at a certain alkali storage capacity, so as to achieve the purpose of continuous deacidification. At present, the common deacidification methods for paper include liquid phase deacidification and gas phase deacidification, but there are poor deacidification effects, acid regurgitation, and excessive local alkalinity, which damages the fiber again. Therefore, the fiber should be reinforced while deacidification to extend the protection period of the paper. However, there are some defects in the simultaneous deacidification and reinforcement, such as the unstable and expensive source of reinforcement materials, the use of highly volatile and toxic reagents as solvents, the instability of deacidifiers, and harmfulness to the human body. Therefore, while deacidifying and reinforcing the paper, how to overcome the existing conditions and increase the life of the paper is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a paper deacidification and reinforcement microcapsule and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0007] (1) respectively preparing a chitosan quaternary ammonium salt solution and a carboxymethyl cellulose solution, and mixing the two solutions uniformly under stirring to obtain a chitosan quaternary ammonium salt-carboxymethyl cellulose solution, and then preparing a calcium carbonate-ethanol suspension;

[0008] (2) Adding the calcium carbonate-ethanol suspension into the chitosan quaternary ammonium salt-carboxymethyl cellulose solution, emulsifying at high speed, and obtaining deacidified reinforced microcapsules.

[0009] Furthermore, the mass concentration of chitosan quaternary ammonium salt in the chitosan quaternary ammonium salt solution in step (1) is 0.5%-5%; and the preparation method thereof is: adding chitosan quaternary ammonium salt to water, and stirring the mixture fully under mechanical stirring to obtain.

[0010] Furthermore, the mass concentration of carboxymethyl cellulose in the carboxymethyl cellulose solution in step (1) is 0.2%-4%; and the preparation method thereof is as follows: adding carboxymethyl cellulose to water, and stirring the mixture fully under mechanical stirring to obtain.

[0011] Furthermore, in the step (1), the volume ratio of the chitosan quaternary ammonium salt solution to the carboxymethyl cellulose solution is (1-10): (2-15).

[0012] Furthermore, the mass concentration of calcium carbonate in the calcium carbonate-ethanol suspension in step (1) is 0.5%-2%; and the preparation method thereof is: taking nano calcium carbonate and adding it into ethanol with a volume concentration of 95% to obtain.

[0013] Furthermore, in the step (2), the volume ratio of the calcium carbonate-ethanol suspension added to the chitosan quaternary ammonium salt-carboxymethyl cellulose solution is (1-8): (1-6).

[0014] Furthermore, in step (2), the high-speed shearing rate is 8000 r / min-10000 r / min, and the time is 2 min-5 min;

[0015] Alternatively, the emulsification temperature in step (2) is 50°C-80°C.

[0016] The paper deacidified reinforced microcapsules are prepared by the preparation method as described above.

[0017] The deacidification reinforcement microcapsules as described above are used in deacidification reinforcement treatment of paper documents.

[0018] The method for deacidification and reinforcement of paper documents using the deacidification and reinforcement microcapsules as described above comprises spraying the deacidification and reinforcement microcapsules evenly onto the surface of the paper documents in the form of a spray, and then placing the paper in a constant temperature and humidity chamber at a temperature of 20-24°C and a relative humidity of RH30-52% for hanging and drying for 24-48 hours.

[0019] The advantages and positive effects achieved by the present invention are:

[0020] 1. The present invention uses alcohol and water as a solvent, nano calcium carbonate as a core material, chitosan quaternary ammonium salt and carboxymethyl cellulose as wall materials, and finally obtains deacidified and reinforced microcapsules through complex coagulation reaction. Nanomaterials are selected as core materials to improve the permeability to paper. The prepared microcapsules have a high alkali storage capacity. The preparation and use methods of the deacidified and reinforced microcapsules of the present invention are simple and convenient, and have good deacidification and reinforcement effects, so that the paper presents alkalinity and anti-aging properties after treatment, which can effectively improve the durability and shelf life of the paper.

[0021] 2. The pH of the paper treated by the present invention is within an optimal range, and the treated paper is alkaline and has a certain anti-aging property. In addition, the mechanical properties of the treated paper are improved by 16%-36%, and the paper has a higher reserve alkali content, thereby avoiding the phenomenon of acid reversion and increasing the life of the paper.

[0022] 3. The deacidification reinforcement microcapsules prepared by the present invention are a mixture of alcohol and water, which can improve the problems of excessive local alkali of paper, wrinkling after drying, poor deacidification, etc. during the deacidification reinforcement process. At the same time, the operation is simple, and the prepared deacidification reinforcement microcapsules are safe and environmentally friendly, and are harmless to paper and the storage environment.

[0023] 4. Compared with untreated paper artifacts, the pH value of the treated samples is alkaline, and the mechanical strength of the paper is significantly improved by 16%-36%. The alkali reserve can reach 210-246mmol / kg, which increases the preservation time of the paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a SEM image of the deacidified reinforced microcapsules prepared in the present invention;

[0025] Figure 2 This is the SEM image of the paper without protection treatment in the present invention;

[0026] Figure 3 This is the SEM image of the paper without protection and dry heat treatment in the present invention;

[0027] Figure 4 This is a SEM image of the paper treated with protection in the present invention;

[0028] Figure 5 This is a SEM image of paper that has been protected and dry-heat aged in the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments. The following embodiments are descriptive rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0030] The various experimental operations involved in the specific embodiments are all routine techniques in the art. For parts not specially annotated in this document, ordinary technicians in the art can implement them by referring to various commonly used reference books, scientific and technological literature or related instructions, manuals, etc. before the filing date of this invention.

[0031] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0032] (1) respectively preparing a chitosan quaternary ammonium salt solution and a carboxymethyl cellulose solution, and mixing the two solutions uniformly under stirring to obtain a chitosan quaternary ammonium salt-carboxymethyl cellulose solution, and then preparing a calcium carbonate-ethanol suspension;

[0033] (2) Adding the calcium carbonate-ethanol suspension into the chitosan quaternary ammonium salt-carboxymethyl cellulose solution, emulsifying at high speed, and obtaining deacidified reinforced microcapsules.

[0034] Preferably, the mass concentration of chitosan quaternary ammonium salt in the chitosan quaternary ammonium salt solution in step (1) is 0.5%-5%. The preparation method is: adding chitosan quaternary ammonium salt to water, and stirring the mixture fully under mechanical stirring to obtain.

[0035] Preferably, the mass concentration of carboxymethyl cellulose in the carboxymethyl cellulose solution in step (1) is 0.2%-4%. The preparation method is: adding carboxymethyl cellulose to water, and stirring the mixture fully under mechanical stirring to obtain.

[0036] Preferably, the volume ratio of the chitosan quaternary ammonium salt solution to the carboxymethyl cellulose solution in step (1) is (1-10):(2-15).

[0037] Preferably, the mass concentration of calcium carbonate in the calcium carbonate-ethanol suspension in step (1) is 0.5%-2%; and the preparation method thereof is: taking nano calcium carbonate and adding it into ethanol with a volume concentration of 95% to obtain.

[0038] Preferably, in step (2), the volume ratio of the calcium carbonate-ethanol suspension added to the chitosan quaternary ammonium salt-carboxymethyl cellulose solution is (1-8): (1-6).

[0039] Preferably, the high-speed shearing rate in step (2) is 8000 r / min-10000 r / min, and the time is 2 min-5 min;

[0040] Alternatively, the emulsification temperature in step (2) is 50°C-80°C.

[0041] The paper deacidified reinforced microcapsules are prepared by the preparation method as described above.

[0042] The deacidification reinforcement microcapsules as described above are used in deacidification reinforcement treatment of paper documents.

[0043] The method for deacidification and reinforcement of paper documents using the deacidification and reinforcement microcapsules as described above comprises spraying the deacidification and reinforcement microcapsules evenly onto the surface of the paper documents in the form of a spray, and then placing the paper in a constant temperature and humidity chamber at a temperature of 20-24°C and a relative humidity of RH30-52% for hanging and drying for 24-48 hours.

[0044] Specifically, the relevant preparation and detection are as follows:

[0045] Example 1

[0046] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0047] (1) 0.2 g of chitosan quaternary ammonium salt was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 1; 0.4 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 2; solution 1 and solution 2 were mixed in a volume ratio of 1:1 to obtain solution 3;

[0048] (2) 0.2 g of nano-calcium carbonate was added to 100 g of 95% ethanol to obtain solution 4. Solution 4 was slowly added to solution 3 at 50°C. The volume ratio of solution 4 to solution 3 was 1:1. High-speed shear emulsification was performed at a rotation speed of 8000 r / min for 2 min–5 min to obtain deacidified reinforced microcapsules.

[0049] (3) At room temperature, the obtained deacidified reinforced microcapsules were transferred to a spray pot and sprayed on the hanging paper. Then, the samples were placed in a constant temperature and humidity environment at a temperature of (23±1)°C and a relative humidity of (50±2)% for 24 hours, and the pH and mechanical properties of the paper were tested. Another piece of treated paper was subjected to dry heat aging treatment at 105°C±2°C for 72 hours, and the pH and mechanical properties of the paper were tested.

[0050] Example 2

[0051] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0052] (1) 0.4 g of chitosan quaternary ammonium salt was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 1; 0.2 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 2; solution 1 and solution 2 were mixed in a volume ratio of 2:1 to obtain solution 3;

[0053] (2) 0.2 g of nano-calcium carbonate was added to 100 g of 95% ethanol to obtain solution 4. Solution 4 was slowly added to solution 3 at 60°C. The volume ratio of solution 4 to solution 3 was 2:1. High-speed shear emulsification was performed at a speed of 10,000 r / min for 2 min–5 min to obtain deacidified reinforced microcapsules.

[0054] (3) At room temperature, the obtained deacidified reinforced microcapsules were transferred to a spray pot and sprayed on the hanging paper. Then, the samples were placed in a constant temperature and humidity environment at a temperature of (23±1)°C and a relative humidity of (50±2)% for 24 hours, and the pH and mechanical properties of the paper were tested. Another piece of treated paper was subjected to dry heat aging treatment at 105°C±2°C for 72 hours, and the pH and mechanical properties of the paper were tested.

[0055] Example 3

[0056] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0057] (1) 0.8 g of chitosan quaternary ammonium salt was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 1; 0.4 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 2; solution 1 and solution 2 were mixed in a volume ratio of 3:2 to obtain solution 3;

[0058] (2) 0.2 g of nano-calcium carbonate was added to 100 g of 95% ethanol to obtain solution 4. Solution 4 was slowly added to solution 3 at 70°C. The volume ratio of solution 4 to solution 3 was 3:1. High-speed shear emulsification was performed at a speed of 10,000 r / min for 2 min–5 min to obtain deacidified reinforced microcapsules.

[0059] (3) At room temperature, the obtained deacidified reinforced microcapsules were transferred to a spray pot and sprayed on the hanging paper. Then, the samples were placed in a constant temperature and humidity environment at a temperature of (23±1)°C and a relative humidity of (50±2)% for 24 hours, and the pH and mechanical properties of the paper were tested. Another piece of treated paper was subjected to dry heat aging treatment at 105°C±2°C for 72 hours, and the pH and mechanical properties of the paper were tested.

[0060] Comparative Example 1

[0061] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0062] (1) 0.2 g of chitosan quaternary ammonium salt was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 1; 0.4 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 2; and solution 1 and solution 2 were mixed in a volume ratio of 1:1 to obtain solution 3.

[0063] (3) At room temperature, the obtained deacidified reinforced microcapsules were transferred to a spray pot and sprayed on the hanging paper. Then, the samples were placed in a constant temperature and humidity environment at a temperature of (23±1)°C and a relative humidity of (50±2)% for 24 hours, and the pH and mechanical properties of the paper were tested. Another piece of treated paper was subjected to dry heat aging treatment at 105°C±2°C for 72 hours, and the pH and mechanical properties of the paper were tested.

[0064] Comparative Example 2

[0065] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0066] (1) 0.2 g of chitosan quaternary ammonium salt was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 1; 0.4 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred under mechanical stirring to obtain solution 2; solution 1 and solution 2 were mixed in a volume ratio of 1:1 to obtain solution 3;

[0067] (2) 0.2 g of nano-silica was added to 100 g of 95% ethanol to obtain solution 4. Solution 4 was slowly added to solution 3 at 70° C. The volume ratio of solution 4 to solution 3 was 1:1. High-speed shear emulsification was performed at a speed of 8000 r / min for 2 min–5 min to obtain deacidified reinforced microcapsules. The subsequent use and testing methods were the same as those in Example 1.

[0068] Comparative Example 3

[0069] A method for preparing paper deacidification reinforcement microcapsules comprises the following steps:

[0070] (1) 0.2 g of polyvinyl alcohol was added to 100 g of water, and the mixture was stirred mechanically to obtain solution 1. 0.4 g of carboxymethyl cellulose was added to 100 g of water, and the mixture was stirred mechanically to obtain solution 2. Solution 1 and solution 2 were mixed in a volume ratio of 1:1 to obtain solution 3. The subsequent use and testing methods were the same as those in Example 1.

[0071] The experimental results of the above examples and comparative examples are shown in Table 1.

[0072] Table 1

[0073]

[0074] The test results show that, in the embodiments of the present invention, after the paper is deacidified, the pH value of the paper is alkaline, and the alkali retention is 212mmol / kg-246mmol / kg, which avoids the phenomenon of acid reversion; at the same time, the tensile index of the paper is also increased by 16%-36%, which has a comprehensive effect of protecting the paper. From the data analysis, compared with the comparative example, it can be concluded that after the treatment, there is a big difference in the reinforcement effect between the embodiment 1 and the comparative example 1, and the comparative example 1 has a reinforcement effect on the paper, and there is no good deacidification effect. At the same time, there is a big gap in the alkali reserve. At the same time, compared with comparative examples 2 and 3, there are certain differences in the pH, tensile index, and alkali reserve of the paper after treatment, especially after aging treatment. Compared with the embodiment, the decline rate of the performance parameters of the comparative example is higher than the comparison parameters of the embodiment.

[0075] At the same time, by comparing Example 1, Comparative Example 2 and Comparative Example 3, it can be seen that the chitosan quaternary ammonium salt and the nano-calcium carbonate in the method of the present invention have a synergistic effect, which can synergistically improve the relevant properties of the prepared paper deacidification reinforcement microcapsules.

[0076] from Figure 1 It can be seen that the microcapsules prepared in Example 1 are uniform in size, present a spherical shape as a whole, and are dispersed relatively tightly. They can be well adsorbed and filled in paper fibers and fiber gaps, thereby having a good effect on strengthening and deacidifying paper fibers; Figure 2 It can be seen that there are a lot of gaps and broken fibers entangled together on the surface of old paper; Figure 3 It can be seen that after the dry heat aging treatment, the old paper fibers are broken, and the gaps between the paper fibers become larger, indicating that after the artificial dry heat aging treatment, the paper fibers are destroyed, causing the physical properties of the paper to decline; Figure 4 It can be seen that after the paper fiber is treated with the microcapsules prepared in Example 1, part of the microcapsules are adsorbed on the surface of the paper fiber, and part of the microcapsules are filled in the gaps between the fibers, thereby strengthening and deacidifying the fibers; Figure 5 It can be seen that after the microcapsules prepared in Example 1 were treated and aged, the fibers of the paper were not obviously broken. At the same time, through the pH test of the paper, it can be seen that the microcapsules have a good protection and deacidification effect on the paper.

[0077] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing paper deacidification reinforcement microcapsules, characterized in that: The following steps are involved: (1) respectively preparing a chitosan quaternary ammonium salt solution and a carboxymethyl cellulose solution, and mixing the two solutions under stirring to obtain a chitosan quaternary ammonium salt-carboxymethyl cellulose solution, and then preparing a calcium carbonate-ethanol suspension; (2) Adding the calcium carbonate-ethanol suspension into the chitosan quaternary ammonium salt-carboxymethyl cellulose solution, emulsifying at high speed, and obtaining deacidified reinforced microcapsules.

2. The preparation method according to claim 1, characterized in that: The mass concentration of chitosan quaternary ammonium salt in the chitosan quaternary ammonium salt solution in step (1) is 0.5%-5%. The preparation method comprises the following steps: adding chitosan quaternary ammonium salt to water, and stirring the water sufficiently under mechanical stirring to obtain the chitosan quaternary ammonium salt.

3. The preparation method according to claim 1, characterized in that: The mass concentration of carboxymethyl cellulose in the carboxymethyl cellulose solution in step (1) is 0.2%-4%. The preparation method is as follows: adding carboxymethyl cellulose to water and stirring the water sufficiently under mechanical stirring to obtain the carboxymethyl cellulose.

4. The preparation method according to claim 1, characterized in that: In the step (1), the volume ratio of the chitosan quaternary ammonium salt solution to the carboxymethyl cellulose solution is 1-10:2-15.

5. The preparation method according to claim 1, characterized in that: The mass concentration of calcium carbonate in the calcium carbonate-ethanol suspension in step (1) is 0.5%-2%. The preparation method is: adding nano calcium carbonate to ethanol with a volume concentration of 95% to obtain.

6. The preparation method according to claim 1, characterized in that: In the step (2), the volume ratio of the calcium carbonate-ethanol suspension added to the chitosan quaternary ammonium salt-carboxymethyl cellulose solution is 1-8:1-6.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (2), the high-speed shearing rate is 8000 r / min-10000 r / min, and the time is 2 min-5 min; Alternatively, the emulsification temperature in step (2) is 50°C-80°C.

8. Paper deacidified reinforced microcapsules prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the deacidification and reinforcement microcapsules as claimed in claim 8 in deacidification and reinforcement treatment of paper documents.

10. A method for deacidification and reinforcement of paper documents using the deacidification and reinforcement microcapsules as claimed in claim 8, characterized in that: The method comprises spraying the deacidified reinforcement microcapsules uniformly onto the surface of the paper document in the form of a spray, and then placing the paper in a constant temperature and humidity chamber with a temperature of 20-24° C. and a relative humidity of RH30-52% for hanging and drying for 24-48 hours.

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