A natural flattening and drying method for rotten documents based on interface support and moisture regulation

Abstract

The application discloses a kind of based on interface support and moisture regulation rotten paper document natural flat drying method, belong to paper document protection and restoration technical field.The present application constructs wet state support interface with the thickness of 0.15~1.0 mm hydrophilic porous paper, and the wet state restoration is carried out by being flatly attached to the interface, and natural drying is carried out by this as support.The method utilizes the capillary structure of hydrophilic porous paper, and the water evaporation in the document body is physically buffered and guided, so that the water is slowly and evenly released along the thickness direction, thereby reducing the capillary shrinkage stress caused by local moisture gradient from the root, effectively inhibiting the curling, warping and tearing in the drying process.The present application realizes wet state restoration and natural drying in one, without transferring fragile documents throughout the process, without applying glue alum or hot pressing, significantly improving the flatness and safety of natural drying of rotten ancient books, archives, paintings and other paper documents.

Description

Technical Field

[0001] This invention belongs to the field of document protection and restoration technology, specifically relating to a natural flattening and drying method applicable to decayed paper documents such as ancient books, archives, and paintings, as well as decayed silk textiles such as ancient silk paintings, silk fabrics, and silk clothing. Background Technology

[0002] In the field of document preservation and restoration, paper and silk documents often exhibit a deteriorated state with loose fiber networks and significant loss of mechanical properties due to temperature and humidity fluctuations, acidification, photo-oxidation, and microbial erosion. Achieving flatness and dryness after wet restoration is particularly challenging.

[0003] Currently, the following are the main technical approaches for drying fragile documents:

[0004] Firstly, there's the traditional method of mounting documents on a small backing and hot pressing. This method involves mounting the documents on a small backing and then attaching them to a flat wall surface to dry naturally, or combining this with the use of a hot press to apply pressure and heat for drying. However, for damaged documents, this method easily creates significant shrinkage stress within the document during the drying process due to uneven moisture migration or rapid loss. Because damaged documents have very low strength, they cannot withstand this stress, often resulting in warping, curling, wrinkling, or even secondary tearing after drying, which is counterproductive.

[0005] Secondly, there is the method of applying alum and then drying. To overcome the above problems, restorers often apply alum and glue solution (a mixture of alum and gelatin) to the decayed documents before and after mounting to strengthen them and prevent them from cracking on the wall. However, the use of alum and glue solution has been proven by numerous studies to accelerate further embrittlement and acidification of the documents, and has long been criticized.

[0006] Thirdly, there is the interface drying technique represented by "friction-assisted drying." The American Conservation Society (AIC)'s *Book and Paper Conservation Wiki* details this method: the paper to be treated is sandwiched between two sheets of moistened Asian paper (such as gampi or mulberry bark) to form a "sandwich" structure. The friction generated by the synchronous shrinkage of the three layers of paper achieves smooth drying. This method is highly effective for thin paper and generally brittle paper. However, its mechanism relies on the synchronous shrinkage between the paper to be treated and the friction paper. For decayed paper documents with severely broken cellulose molecular chains and lost effective shrinkage capacity, their deformation behavior is incompatible with the friction paper. Forcing its application not only fails to achieve smoothness but may also cause new tearing damage due to the uncoordinated shrinkage stress. Furthermore, this method requires spatial transfer of the moistened paper to be treated, which poses a very high operational risk for decayed paper documents with near-zero strength in a wet state. In addition, achieving smooth drying is even more difficult for hydrophobic decayed paper documents. For literature on silk fabrics, the fiber shrinkage mechanism differs from that of paper, and the "synchronous shrinkage" logic relied upon by the friction-assisted drying method is even more difficult to apply.

[0007] In summary, the common problem with the aforementioned existing technologies is that they all attempt to "counteract" or "match" the document's own drying shrinkage behavior through external constraints (wall adhesion, alum reinforcement, friction paper clamping), without fundamentally controlling the moisture evaporation process itself. For decayed documents that have lost all shrinkage force and have near-zero wet strength, such "counteracting" or "matching" technical approaches are unlikely to be effective. How to achieve safe, flat, and natural drying of decayed paper and silk documents without using alum reinforcement, without relying on the document's own shrinkage force, without being limited by the differences in hydrophilicity and hydrophobicity, and without avoiding the risk of moisture transfer has become a pressing technical problem in this field that remains unsolved. Summary of the Invention

[0008] The purpose of this invention is to provide a natural flattening and drying method for decayed paper documents based on interface support and moisture control, aiming to solve the technical problems in the prior art such as deformation damage caused by drying shrinkage stress, reliance on sizing and alum reinforcement, and the risk of moisture transfer in decayed paper documents and decayed silk documents.

[0009] To achieve the above objectives, the present invention provides a method for natural leveling and drying of decayed literature based on interface support and moisture regulation, comprising the following steps:

[0010] Step 1: Lay the hydrophilic porous auxiliary paper with a thickness of 0.15-1.0 mm flat on a flat work surface, use a misting water spray method to evenly wet it, and use a soft brush to sweep it flat and adhere it to the work surface, remove air bubbles, and form a stable wet support interface.

[0011] Step 2: On the wet support interface, perform wet repair treatment on the decayed document to make the decayed document flat and adhere to the surface of the hydrophilic porous auxiliary paper to form a coupler; the decayed document is a decayed paper document or a decayed silk document.

[0012] Step 3: Place the coupler flat on a flat table and let it dry naturally in a clean, sealed indoor environment without strong convection. Then separate the rotten document from the hydrophilic porous auxiliary paper to complete the natural drying of the rotten document.

[0013] Furthermore, in step 1, the thickness of the hydrophilic porous paper dampening agent is preferably 0.5 to 1.0 mm.

[0014] Further, in step 1, the hydrophilic porous auxiliary paper is any one of the following: unsized wood pulp machine-made paper, unsized cotton pulp machine-made paper, auxiliary paper made of 3 to 5 layers of raw Xuan paper, or auxiliary paper made of 3 to 5 layers of bark paper; the hydrophilic porous auxiliary paper has a hydrophilic fiber network and a porous capillary structure.

[0015] Furthermore, in step 1, the work surface is a transparent explosion-proof glass work surface.

[0016] Furthermore, in step 2, the wet remediation treatment is one or more of the conventional cleaning, deacidification, and fragment splicing processes.

[0017] Furthermore, in step 2, after the wet restoration treatment, the surface of the decayed document is treated with absorbent paper and a soft brush to absorb moisture and smooth it. That is, the absorbent paper is laid flat on the surface of the decayed document and gently smoothed with a soft brush to absorb excess free water from the surface, so that the decayed document and the hydrophilic porous auxiliary paper are tightly bonded together by capillary force to form a moisture-controlled coupling.

[0018] The "coupled body" mentioned in this invention refers to a composite structure formed by the close bonding of rotten documents and hydrophilic porous auxiliary paper due to capillary forces.

[0019] Furthermore, in step 2, the decayed paper documents can be any one of ancient books, archives, or paintings and calligraphy.

[0020] Furthermore, in step 2, the document containing the rotten silk fabric can be any one of silk painting, silk fabric, or silk clothing.

[0021] Furthermore, in step 3, the coupler is placed flat on a flat table and left to air dry naturally in a clean, sealed indoor environment without strong convection for 5 to 24 hours.

[0022] The core technical principle of this invention differs fundamentally from the aforementioned prior art: the technical logic of prior art (especially the friction-assisted drying method) is "dynamic shrinkage matching"—relying on the synchronous shrinkage of the paper to be treated and the auxiliary paper during the drying process, using interlayer friction to constrain paper deformation. This logic presupposes that the paper to be treated itself has a shrinkable fiber network. This invention completely abandons this logic, instead adopting a technical path of "static interface support + moisture migration regulation": the hydrophilic porous auxiliary paper does not "flatten" the document through its own synchronous shrinkage, but rather acts as a static support interface with moisture buffering and guiding functions. During the drying process, it utilizes its porous capillary structure to physically buffer and regulate the rate of moisture evaporation within the document itself, reducing the moisture gradient within the capillary fibers of the decayed document, thereby fundamentally weakening the capillary shrinkage stress during document drying. Simultaneously, this hydrophilic porous auxiliary paper possesses excellent mechanical strength in a wet state, providing full physical support for the weak and decayed document throughout the process, completely avoiding transfer and handling damage to the document in a wet state.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. A fundamental revolution in drying mechanisms. This invention abandons the approach of friction-assisted drying methods that rely on the "synchronous shrinkage" of paper to generate friction. Instead, it innovatively adopts a strategy of "static interface support" and "moisture migration regulation." Through the capillary buffering effect of hydrophilic porous paper, the capillary shrinkage stress of decayed documents during natural drying is effectively reduced. This achieves macroscopic flatness without relying on the mechanical properties of the paper itself, fundamentally solving the industry pain point of warping and tearing of decayed documents due to shrinkage stress.

[0025] 2. Completely eliminates dependence on alum-based adhesives. Unlike alum-based reinforcement methods, this invention provides sufficient mechanical strength to wet-state decayed materials through an interfacial support system, ensuring structural stability throughout the drying process. Therefore, this method completely eliminates the need for any alum-based adhesives or synthetic reinforcement agents, not only removing the risk of accelerated aging of materials caused by alum-based adhesives but also representing a truly "material-friendly" green restoration method.

[0026] 3. Achieving integrated "repair-drying" eliminates operational risks. Unlike friction-assisted drying methods that require spatial transfer of wetted paper, this invention integrates the wet-state repair processes—including cleaning, deacidification, and splicing—with the final natural drying on the same support platform. The damaged documents in their wet state require no handling or transfer throughout the entire process, minimizing secondary damage caused by movement or handling, and significantly improving operational safety. This is especially suitable for extremely fragile and easily broken endangered documents.

[0027] 4. Simple process and wide applicability. Unlike the wall-drying method, which relies on a wall surface and hot-pressing equipment, this invention is simple to operate, requires no expensive heating and pressurizing equipment, and can be implemented in ordinary repair workbenches and indoor environments. Furthermore, this method is not limited to documents of specific materials; it is highly applicable to various types of decayed paper documents such as ancient books, archives, and paintings, as well as decayed silk documents such as silk paintings, silk fabrics, and silk clothing, possessing extremely high value for widespread application. Attached Figure Description

[0028] Figure 1 This is a diagram showing the effect of naturally drying the rotten paper in Comparative Example 1 using tung oil paper.

[0029] Figure 2 This is a diagram showing the effect of naturally drying a single layer of raw Xuan paper on the rotten paper in Comparative Example 2.

[0030] Figure 3 This is a diagram showing the effect of naturally drying the rotten paper in Example 1 using cotton pulp mechanical paper.

[0031] Figure 4 This is a diagram showing the effect of naturally drying five layers of raw Xuan paper on the rotten paper in Example 2.

[0032] Figures 1-4 In the image, (a) is the natural state, (b) is the wet state, (c) is the dried state, and (d) is the side-polished state after drying. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to these embodiments.

[0034] Comparative Example 1

[0035] This comparative example uses traditional hydrophobic auxiliary paper (tung oil paper) as the interface support material, aiming to simulate the conventional approach of using a hydrophobic isolation layer for paper drying in existing technologies.

[0036] Step 1: Take a piece of tung oil paper that is larger than the damaged paper to be repaired, lay it flat on the explosion-proof glass work surface, and wet the tung oil paper with water before smoothing it out.

[0037] Step 2: On the surface of the tung oil paper from Step 1, perform routine cleaning, deacidification, and splicing repair treatments on the rotten paper. Then, lay absorbent paper flat on the surface of the rotten paper, use a soft brush to smooth it out, absorb excess water, and ensure that it adheres tightly to the tung oil paper.

[0038] Step 3: Place the wet, rotten paper from Step 2, along with the tung oil paper, on a flat table to air dry naturally for 12 hours. Then peel it off the surface of the tung oil paper to complete the natural drying of the rotten paper.

[0039] Comparative Example 2

[0040] This comparative example uses hydrophilic thin auxiliary paper (single-layer raw Xuan paper) as the interface support material to verify the improvement of drying effect after the introduction of hydrophilic materials, and at the same time reveal the limitations of this technical approach when the thickness is insufficient.

[0041] Step 1: Take a piece of raw Xuan paper that is larger than the damaged paper to be repaired, lay it flat on the explosion-proof glass work surface, and wet the raw Xuan paper with water before smoothing it out.

[0042] Step 2: On the surface of the raw Xuan paper from Step 1, perform routine cleaning, deacidification, and splicing repair treatments on the rotten paper. Then, lay absorbent paper flat on the surface of the rotten paper, use a soft brush to smooth it out, absorb excess water, and keep it in close contact with the raw Xuan paper.

[0043] Step 3: Place the wet, rotten paper from Step 2, along with the raw Xuan paper, on a flat table to air dry naturally for 12 hours. Then, peel it off from the surface of the raw Xuan paper. This completes the natural drying of the rotten paper document.

[0044] Example 1

[0045] In this embodiment, hydrophilic porous auxiliary paper (unsized cotton pulp mechanical paper with a thickness of approximately 0.15 mm) was used as an interface support material to verify its moisture regulation and stress suppression effects during the natural drying of rotten paper.

[0046] Step 1: Take a piece of unadhesive cotton pulp mechanical paper that is larger than the damaged paper to be repaired, lay it flat on the explosion-proof glass work surface, and use water spraying to evenly wet the cotton pulp mechanical paper. Use a soft brush to smooth and adhere it to the work surface, remove air bubbles, and form a stable wet support interface.

[0047] Step 2: On the wet support interface in Step 1, perform routine cleaning, deacidification and splicing repair treatments on the rotten paper. Then, lay absorbent paper flat on the surface of the rotten paper and gently sweep it with a soft brush to absorb excess free water on the surface, so that the rotten paper and the cotton pulp mechanical paper are tightly bonded to form a coupler with controllable moisture.

[0048] Step 3: Place the coupler from Step 2 (wet, rotten paper along with cotton pulp machine paper) flat on a flat table. Let it stand and dry naturally for 12 hours in a clean, sealed indoor environment without strong convection. Then peel it off from the surface of the cotton pulp machine paper to complete the natural drying of the rotten paper.

[0049] Example 2

[0050] In this embodiment, a hydrophilic porous auxiliary paper (composed of 5 layers of raw Xuan paper, with a thickness of approximately 0.5 mm) was used as an interface support material to verify the effect of the thickness of the hydrophilic porous auxiliary paper on moisture regulation and stress suppression during the natural drying of rotten paper.

[0051] Step 1: Take 5 sheets of raw Xuan paper that are larger than the damaged paper to be repaired, stack them neatly, lay them flat on the explosion-proof glass work surface, and use water spraying to evenly wet the 5 layers of raw Xuan paper. Use a soft brush to smooth and adhere them to the work surface, remove air bubbles, and form a stable wet support interface.

[0052] Step 2: On the wet support interface in Step 1, perform routine cleaning, deacidification and splicing repair treatments on the rotten paper. Then, lay absorbent paper flat on the surface of the rotten paper and gently sweep it with a soft brush to absorb excess free water on the surface, so that the rotten paper and the 5 layers of raw Xuan paper are tightly bonded to form a coupler with controllable moisture.

[0053] Step 3: Place the coupling body from Step 2 (wet, rotten paper along with 5 layers of raw Xuan paper) flat on a flat table. Let it stand and dry naturally for 12 hours in a clean, sealed indoor environment without strong convection. Then peel it off from the surface of the 5 layers of raw Xuan paper to complete the natural drying of the rotten paper.

[0054] Figures 1-4 The figures are, in order, the natural state (a), wet state (b), dried state (c), and side-gloss state (d) of the rotten paper in Comparative Example 1, Comparative Example 2, Example 1, and Example 2. Figures 1-3 The top row shows drying examples of hydrophilic, decayed ancient book paper, while the bottom row shows drying examples of hydrophobic, decayed Buddhist scripture paper. Figure 4 This is merely a dried example of hydrophobic, decayed Buddhist scripture paper.

[0055] Depend on Figure 1 It is evident that the tung oil paper used as the hydrophobic barrier in Comparative Example 1 primarily serves a physical support function during the drying process, lacking moisture absorption and regulation capabilities. The sample darkened significantly in color after wetting, indicating the fibers were in a moistened and softened state. While the overall shape of the decayed ancient book paper sample remained largely intact after drying, local undulations and slight wrinkles were observed under side lighting, suggesting uneven moisture evaporation and the presence of some shrinkage stress. The decayed Buddhist scripture sample, due to its more severe damage, missing parts, and edge aging, retained its main shape after drying, but noticeable wrinkling, warping, and surface unevenness were visible under side lighting, with the risk of further deformation or crack expansion at the damaged edges. These results demonstrate that relying solely on the physical support of the hydrophobic interface is insufficient to effectively regulate moisture migration within decayed paper and to suppress the damage caused by drying shrinkage stress to fragile paper.

[0056] Depend on Figure 2 It is evident that, compared to the hydrophobic tung oil paper of Comparative Example 1, single-layer raw Xuan paper possesses a certain water absorption capacity, capable of absorbing excess moisture from the surface of decayed paper to some extent. However, due to its thinness (approximately 0.1 mm), the capillary capacity and wet support strength of the raw Xuan paper are quite limited. After wetting, the sample darkens in color and softens overall; although it largely retains its original shape after drying, local wrinkles, edge warping, and deformation of damaged areas are still visible upon planar observation. Side-lit results further reveal significant surface undulations and wrinkles, with insufficient flatness after drying. These results indicate that, due to its insufficient thickness, the capillary capacity of raw Xuan paper is limited, preventing it from continuously buffering moisture throughout the drying process; simultaneously, its poor wet strength makes it difficult to provide sufficient restraint when decayed paper shrinks due to water loss, resulting in inadequate dispersion of internal shrinkage stress. Therefore, while a simple hydrophilic thin-layer material is superior to a hydrophobic barrier layer, it still cannot meet the dual requirements of decayed paper for moisture control and mechanical support.

[0057] Depend on Figure 3 As can be seen, Example 1 achieved a significantly improved drying effect compared to Comparative Examples 1 and 2. The decayed ancient book paper sample maintained its overall morphology well after natural drying. No obvious new wrinkles, cracks, or expanded damage were observed during planar observation. Under side lighting, only slight undulations were observed, and the overall flatness was good. For the more severely deteriorated hydrophobic decayed Buddhist scripture sample, although its original damage, missing parts, and edge decay were very obvious, the main shape was still well maintained after drying, and no obvious tears or further expansion of cracks were observed in the text area. Under side lighting, only slight local shrinkage and edge undulations were visible, and the overall degree of deformation was far less than that of Comparative Examples 1 and 2.

[0058] Depend on Figure 4 As can be seen, Example 2 achieved a more significantly improved drying effect compared to Comparative Example 2 and Example 1. For the more severely deteriorated hydrophobic and decayed Buddhist scripture sample, although its original damage, missing parts, and edge decay were very obvious, the main body shape remained good after drying, and no obvious tearing or further expansion of cracks was observed in the text area. Under side lighting, almost no wrinkling or edge undulation was visible, and the flatness after drying was far superior to Comparative Example 2 and Example 1.

[0059] The mechanism behind these results lies in the abundant three-dimensional porous capillary structure within the hydrophilic porous paper additive. On one hand, this provides ample capillary capacity, allowing for continuous absorption and redistribution of moisture from the rotten paper throughout the drying process. This enables moisture to migrate slowly downwards along the thickness direction, preventing stress concentration caused by localized moisture gradients. On the other hand, its excellent mechanical strength in a wet state provides stable support and constraint for the completely weakened paper, dispersing the paper's shrinkage stress. Ultimately, this achieves the dual goals of uniform moisture release and effective stress dissipation.

[0060] Further integration Figures 1 to 4 The experimental results clearly show the influence of different technical approaches on the drying effect of rotten paper, as detailed in Table 1.

[0061] Table 1. Comparative Analysis of the Influence of Four Different Auxiliary Papers on the Drying Effect of Deteriorated Paper

[0062]

[0063] Therefore, Comparative Example 1 represents the traditional physical isolation drying approach, which essentially places the paper to be dried on a hydrophobic interface that does not participate in moisture exchange. This approach fails to address the core issue of uneven moisture evaporation within the paper. While Comparative Example 2 introduces a hydrophilic material, its insufficient thickness limits its capillary capacity and wet strength, making it an inadequate improvement. Example 1, based on Comparative Example 2, improves the thickness of the hydrophilic auxiliary paper, achieving better capillary capacity and wet strength to meet the drying requirements of the rotten paper, effectively improving the smooth drying effect. Example 2, based on Comparative Example 2 and Example 1, further improves the thickness of the hydrophilic porous auxiliary paper, constructing a drying support interface with both "moisture guidance" and "stress dissipation" functions. This technical approach differs fundamentally from the aforementioned two comparative examples, achieving unexpected technical results. Even for severely damaged, hydrophobic rotten Buddhist scripture samples, safe and smooth natural drying can be achieved without any reinforcement with sizing solution or hot pressing.

Claims

1. A natural leveling and drying method for decayed documents based on interface support and moisture control, characterized in that, Includes the following steps: Step 1: After wetting the hydrophilic porous auxiliary paper with a thickness of 0.15-1.0 mm, lay it flat on the work surface, sweep it smooth and adhere it to form a wet support interface; Step 2: On the wet support interface, perform wet restoration treatment on the decayed document to make the decayed document flat and adhere to the surface of the hydrophilic porous auxiliary paper to form a coupler; the decayed document is a decayed paper document or a decayed silk document; Step 3: Place the coupler flat on a flat table and allow it to dry naturally in a closed indoor environment without strong convection. Then separate the decayed document from the hydrophilic porous auxiliary paper.

2. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 1, the thickness of the hydrophilic porous paper dampening agent is 0.5 to 1.0 mm.

3. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1 or 2, characterized in that, In step 1, the hydrophilic porous auxiliary paper is any one of the following: unsized wood pulp machine paper, unsized cotton pulp machine paper, auxiliary paper made of 3 to 5 layers of raw Xuan paper, or auxiliary paper made of 3 to 5 layers of bark paper; the hydrophilic porous auxiliary paper has a hydrophilic fiber network and a porous capillary structure.

4. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 1, the work surface is a transparent explosion-proof glass work surface.

5. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 2, the wet remediation process includes one or more of the following: cleaning, deacidification, and splicing.

6. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1 or 3, characterized in that, In step 2, after the wet restoration treatment, the surface of the damaged document is further treated with absorbent paper and a soft brush to absorb moisture and smooth it, so that the damaged document and the hydrophilic porous auxiliary paper can be tightly bonded together.

7. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 2, the decayed paper documents can be any one of ancient books, archives, or paintings and calligraphy.

8. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 2, the document containing the rotten silk fabric can be any one of silk painting, silk fabric, or silk clothing.

9. The natural leveling and drying method for decayed documents based on interface support and moisture control according to claim 1, characterized in that, In step 3, the coupler is placed flat on a flat table and left to air dry naturally in a closed indoor environment without strong convection for 5 to 24 hours.

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