Tortoise shell sheet repairing method

Abstract

The invention relates to the technical field of cultural relic protection, and discloses a tortoise shell piece repairing method which comprises the following steps: S1, applying a first adhesive to the fracture surface of a tortoise shell piece to be repaired, and splicing the fracture parts of the tortoise shell piece; s2, a second adhesive is applied to the outer portions of the spliced tortoise shell pieces, so that the tortoise shell pieces are temporarily fixed; s3, after the first adhesive is cured to form permanent joint, the second adhesive is removed; before S1, the method further comprises a pretreatment step of cleaning and drying the to-be-repaired tortoise shell piece. By adopting a combination mode of internal permanent adhesion and external temporary fixation, accurate alignment and stable maintenance of the tortoise shell sheet during curing are ensured, and non-destructive repair of the tortoise shell sheet body is realized through non-destructive removal of a temporary fixture.

Description

Technical Field

[0001] The present invention relates to the technical field of cultural relics protection, in particular to a method for repairing tortoise shells. Background Art

[0002] Tortoise shell, a component found in various cultural relics, artifacts, and artworks, is primarily composed of keratin. Due to the nature of the material and the long-term environmental changes it may experience, tortoise shell is susceptible to physical damage such as breakage and fragmentation during use, storage, and circulation. Repairing these damaged tortoise shells, particularly rejoining separated fragments, is a routine technical task in the fields of cultural relic conservation and art restoration.

[0003] The existing repair process typically involves applying an adhesive to the fractured section, aligning the fragments, and waiting for the adhesive to cure to form a permanent bond. A key technical step in this process is the effective temporary fixation of the assembled tortoise shell components while the adhesive cures. This fixation aims to maintain precise geometric alignment between the fragments, preventing misalignment due to factors such as gravity and micro-vibration, thereby ensuring that the overall structure after repair is consistent with the original morphology.

[0004] However, achieving this temporary fixation in existing technologies presents several technical challenges. While physical clamping with external devices such as mechanical clamps can provide a strong fixation force, the clamp's contact points can create stress concentrations on the fragile surface of the tortoise shell, posing a risk of indentations, scratches, and even secondary fractures.

[0005] If another method is used, such as using tape or applying other auxiliary adhesives to fix the tortoise shell on the outside, the problem is how to remove these auxiliary materials after the repair is completed. If these auxiliary materials are too firmly bonded to the surface of the tortoise shell, the removal process may cause physical damage to the tortoise shell itself. Even if they can be removed, there are often adhesive residues attached to the surface of the tortoise shell, and cleaning these residues often requires the use of specific chemical solvents. These solvents may react with the base material of the tortoise shell, causing irreversible changes in its surface color, finish or chemical composition. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a method for repairing tortoise shell pieces, which solves the problem in the existing technology of repairing broken tortoise shell pieces, and can not only achieve firm temporary fixation of the splicing parts during the curing period, but also ensure the non-destructive removal of the fixed objects after the repair is completed.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for repairing tortoise shells, comprising the following steps: S1, applying a first adhesive to the fractured surface of the tortoise shell piece to be repaired, and splicing the fractured portion of the tortoise shell piece; S2, applying a second adhesive to the exterior of the spliced ​​tortoise shell pieces to temporarily fix the tortoise shell pieces; S3. After the first adhesive is cured to form a permanent bond, the second adhesive is removed.

[0008] Preferably, before S1, the method further includes: The tortoise shell piece to be repaired is subjected to a pretreatment step of cleaning and drying.

[0009] Preferably, the pretreatment step is specifically: washing the tortoise shell piece to be repaired with pure water, and then drying it naturally.

[0010] Preferably, the first adhesive is an adhesive composition comprising epoxy resin, polyvinyl butyral resin and solvent.

[0011] Preferably, the applying of the first adhesive in S1 is specifically to apply glue on one side of a fracture surface of the tortoise shell piece.

[0012] Preferably, the second adhesive is a hot melt adhesive.

[0013] Preferably, the applying of the second adhesive in S2 is specifically: applying glue in a dotted manner on the front and back sides of the tortoise shell piece along the external cracks formed after the splicing.

[0014] Preferably, the removing of the second adhesive in S3 specifically includes: Using a solvent to soften the second adhesive; The softened second adhesive is physically peeled off.

[0015] Preferably, the solvent is anhydrous ethanol.

[0016] The present invention provides a method for repairing tortoise shells. It has the following beneficial effects: 1. This invention solves the technical problem of precisely aligning and securely holding a broken tortoise shell during the repair process by employing a first adhesive for internal permanent bonding and a second adhesive for external temporary fixation. Specifically, the external temporary fixation structure provides continuous and balanced support throughout the curing cycle of the first adhesive, effectively preventing dislocation caused by gravity or other minor disturbances, thereby ensuring the accurate restoration of the tortoise shell's geometric shape and structural integrity after the repair.

[0017] 2. The present invention achieves non-destructive repair of the tortoise shell body through the specific design of the material selection and removal method of the second adhesive. The selected temporary fixing material can be softened by a specific solvent that matches it, and then completely physically peeled off. This process does not cause any visible changes or damage to the original surface morphology, color, and chemical properties of the tortoise shell. The technical effect of this non-destructive removal of temporary fixings minimizes the impact of the repair intervention on the tortoise shell body and maximizes the protection of the original information of the repaired object.

[0018] 3. The present invention provides a seamless and well-defined procedure, encompassing pretreatment of the tortoise shell, the selection and application of two distinct adhesives, the curing of the internal adhesive, and the removal of external fixation. This systematic design, combining permanent bonding with temporary, reversible fixation, provides a well-defined, controlled, and predictable technical solution for repairing broken tortoise shells, enhancing the standardization and reliability of such repairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A diagram showing the steps of the method of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Please see the attached Figure 1 The embodiment of the present invention provides a method for repairing a tortoise shell, comprising the following steps: S1. Preprocessing This step provides a clean base for subsequent bonding. Use pure water to clean the surface of the repaired tortoise shell to remove dust, dirt, or other contaminants that could affect bonding. Use a soft-bristled brush or other tool to avoid physical damage to the surface. After cleaning, allow the tortoise shell to dry naturally in a clean environment until no visible moisture remains on the fracture surface or surface.

[0022] In this embodiment, step S1 is a pretreatment step, the purpose of which is to provide a clean, dry and physically and chemically stable substrate for the subsequent bonding operation, so as to ensure that the first adhesive can form a reliable bond with the tortoise shell base material.

[0023] The pretreatment step specifically includes cleaning and drying operations on the tortoise shell slices to be repaired.

[0024] During the cleaning process, pure water is used as the cleaning medium. This is because conventional water may contain chloride ions, minerals, or other impurities that, after evaporation, may remain on the surface of the tortoise shell, forming a barrier film or acting as a potential reactant, thereby affecting the wetting and spreading ability of the first adhesive and the ultimate bond strength. Pure water avoids the introduction of these contaminants.

[0025] Cleaning is performed by placing the tortoise shell to be repaired in pure water. Preferably, a soft-bristled brush or other tool should be used to gently scrub the surface of the tortoise shell, especially the area near the fracture. This operation is intended to physically remove dust, loose soil particles, and other contaminants adhering to the surface, while also preventing secondary damage to the tortoise shell itself due to excessive mechanical action.

[0026] After the cleaning operation is completed, a drying operation is performed.

[0027] In this embodiment, natural drying is used. The cleaned tortoise shell pieces are removed from the pure water and placed in a clean, dust-free, and well-ventilated environment. Natural drying, rather than heat drying or forced air drying, is used to avoid thermal stress caused by rapid temperature changes or uneven heating, as well as mechanical stress caused by forced airflow. Such stresses could potentially cause new cracks or deformation in the fragile tortoise shell pieces.

[0028] The drying operation is continued until it is confirmed by visual or instrumental inspection that there is no visible or measurable moisture remaining on the surface of the tortoise shell piece, especially on its porous fractured cross section.

[0029] The pretreatment step creates an ideal interface for the subsequent application of the first adhesive in step S2. A clean, dry fracture surface ensures direct molecular-level contact between the first adhesive composition and the tortoise shell substrate after application, which is the foundation for an effective, durable bond.

[0030] S2. Adhesive application and splicing This step is used to achieve permanent bonding of the fractured surfaces of the tortoise shell.

[0031] First, prepare a first adhesive. This adhesive is an adhesive composition comprising: an epoxy resin, such as Araldite 2020; a polyvinyl butyral resin, such as Butvar B-98; and anhydrous ethanol as a solvent. These components are mixed in a predetermined proportion and stirred to form a uniform adhesive solution.

[0032] In this embodiment, step S2 is the adhesive application and splicing step. Its purpose is to chemically bond the pre-treated fractured surfaces of the tortoise shell slices using a specially formulated adhesive composition to restore their physical integrity. This step is the core operation for forming a permanent and stable repair structure.

[0033] This step specifically includes the preparation of a first adhesive, and subsequent gluing and splicing operations.

[0034] First, the first adhesive is prepared.

[0035] The first adhesive is a multi-component adhesive composition, wherein each component thereof acts synergistically to achieve the expected bonding performance. The components of the composition include: epoxy resin, polyvinyl butyral resin and anhydrous ethanol.

[0036] In this embodiment, the epoxy resin is preferably Araldite 2020. This epoxy resin is selected because it forms a high-strength and highly stable three-dimensional network structure after curing, providing durable structural support for the repaired tortoise shell. Its initial low-viscosity liquid state facilitates subsequent mixing with other components and infiltration of the porous fractured surface of the tortoise shell.

[0037] Polyvinyl butyral resin, such as Butvar B-98, is introduced into the adhesive composition as a modifier to adjust the physical properties of the epoxy resin after curing, such as toughness, and to improve the adhesion of the composition to the tortoise shell substrate.

[0038] Anhydrous ethanol serves as the solvent in this composition. Its primary function is to dissolve the solid polyvinyl butyral resin and reduce the viscosity of the epoxy resin, resulting in a uniform, low-viscosity adhesive solution that is easy to apply. This low viscosity is crucial for applying small amounts of adhesive using precision tools and ensuring that the adhesive penetrates the microscopic pores of the fracture surface.

[0039] The preparation process is as follows: the epoxy resin, polyvinyl butyral resin and anhydrous ethanol are mixed according to a predetermined ratio, and are fully mixed by mechanical stirring or the like until a clear adhesive solution with a uniform appearance is formed.

[0040] After the first adhesive is prepared, gluing and splicing operations are carried out.

[0041] This operation uses a precision dispensing tool, such as a liner pen or similar fine-tipped brush, to achieve precise control over the amount of adhesive applied and the location of application.

[0042] During the specific operation, a small amount of the prepared first adhesive solution is dipped into a precision gluing tool. Subsequently, the adhesive solution is thinly and evenly applied to the fracture surface of one of the tortoise shell pieces to be repaired. This is a single-sided gluing operation, which can minimize the amount of adhesive used while ensuring the bonding strength, in line with the principle of minimum intervention in cultural relics restoration. When applying, it is preferred to concentrate the adhesive on the middle area of ​​the fracture surface to avoid excessive adhesive being squeezed out during subsequent splicing and pressurization, thereby contaminating the original outer surface of the tortoise shell piece.

[0043] After applying the glue, the adhesive-coated fracture surface is immediately aligned with the corresponding fracture surface of the other tortoise shell to be repaired and spliced. During splicing, external pressure is applied to tightly align the two fractured surfaces, ensuring that the gap between the fractured surfaces is completely filled with adhesive and that the tortoise shell has been restored to its original geometry. This pressure also helps to eliminate bubbles in the adhesive layer, forming a continuous, defect-free bonding interface.

[0044] S3, temporary fixation This step is intended to maintain the precise alignment of the joined tortoise shell pieces during the curing of the first adhesive.

[0045] A second adhesive is used to temporarily fix the spliced ​​tortoise shell pieces externally.

[0046] In this embodiment, step S3 is a temporary fixing step, the purpose of which is to apply external mechanical support to the tortoise shell sheet assembly that has been spliced ​​but not yet cured in step S2, so as to ensure that the spliced ​​fracture surface can maintain precise alignment during the curing cycle of the first adhesive to prevent dislocation caused by factors such as gravity, vibration or environmental changes.

[0047] This step is achieved by applying a second adhesive to the outside of the joined tortoise shell pieces. The second adhesive is significantly different from the first adhesive used for permanent bonding in terms of function and properties.

[0048] In this embodiment, the second adhesive is preferably a hot-melt adhesive, or hot melt adhesive. This material is chosen for its physical properties: once applied in a molten state, hot melt adhesive rapidly solidifies upon rapid cooling, providing effective fixing force in a short period of time. Furthermore, its bond to the surface of the tortoise shell relies primarily on physical adhesion, rather than strong chemical bonding. This property is essential for its subsequent non-destructive removal.

[0049] The second adhesive is applied using a temperature-controlled hot-melt glue gun. This temperature-controlled equipment is designed to keep the application temperature of the hot-melt glue within a preset, relatively low range. This prevents localized overheating, which could cause irreversible thermal damage to the physical and chemical properties of the tortoise shell (whose primary component is keratin), thereby ensuring safety during the application process.

[0050] The specific application operations are as follows: After heating a temperature-controlled hot melt glue gun to the desired operating temperature, apply the molten hot melt glue in dots to the exterior of the joined tortoise shell pieces. Each dot of glue spans the external crack formed by the joint, with one end attached to the surface of the tortoise shell piece on one side of the crack and the other end attached to the surface of the tortoise shell piece on the other side of the crack.

[0051] The goal of using a dotted adhesive rather than a linear, continuous application is to minimize the contact area between the second adhesive and the original surface of the tortoise shell while providing sufficient fixing force. This not only embodies the principle of minimal intervention in cultural relic restoration, but also reduces the workload and potential risks of removing the adhesive in the subsequent step S4.

[0052] To ensure balanced support from the fixing structure, spot gluing is performed on both the front and back sides of the tortoise shell component. Specifically, multiple fixing glue points are placed alternately or correspondingly along the crack's front and back sides. This double-sided fixing structure effectively offsets any bending or torsional stresses, maintaining the entire component in a stress-free or stress-balanced state during curing.

[0053] S4. Curing and Removal of Fixings This step includes curing of the first adhesive and removal of the second adhesive.

[0054] First, the tortoise shell pieces processed in step S3 are placed in a stable environment, for example, for 7 days, to allow the first adhesive (epoxy resin system) inside the fracture surface to completely cure, thereby forming a permanent chemical bond with sufficient structural strength between the fracture surfaces.

[0055] In this embodiment, step S4 is the step of curing and removing fixtures. This step logically and temporally follows step S3. Its purpose is to first cure the first adhesive to form a permanent structural bond, and then remove all temporary fixtures in a non-destructive manner, thereby completing the physical repair of the tortoise shell plate.

[0056] This step specifically includes a curing process of the first adhesive and a removal process of the second adhesive.

[0057] First, a curing process of the first adhesive is performed.

[0058] After step S3 is completed, the tortoise shell sheet assembly, with the first adhesive and the second adhesive applied thereto, is placed in a physically and chemically stable environment that is free from significant temperature fluctuations, mechanical vibrations, or other external factors that may interfere with the bonding interface.

[0059] In this stable environment, the first adhesive composition within the fracture surface undergoes a chemical curing reaction. Specifically, the epoxy resin molecules within the composition undergo cross-linking polymerization under the action of an initiator, forming a three-dimensional network of polymer structures. This process transforms the adhesive from a liquid or semi-solid state into a solid with a predetermined mechanical strength.

[0060] To ensure the chemical reaction is complete, the tortoise shell assembly needs to be left to cure for a predetermined period. For example, this period can be set to 7 days. This period is designed to ensure that the first adhesive reaches its final bond strength and structural stability, thereby forming a strong and durable permanent bond between the fractured surfaces of the tortoise shell.

[0061] After confirming that the first adhesive has been completely cured, the second adhesive removal process is started.

[0062] The removal process is intended to completely and without damage remove all temporary fixings (ie, hot melt adhesive spots) applied in step S3 from the surface of the tortoise shell piece.

[0063] Specifically, the removal operation includes two consecutive sub-steps of solvent softening and physical stripping.

[0064] In the solvent softening sub-step, anhydrous ethanol is used as the dedicated removal solvent. This solvent is chosen because it effectively penetrates and weakens the physical adhesion between the hot melt adhesive and the keratin substrate of the tortoise shell, without chemically reacting with the tortoise shell itself or causing damage such as swelling or discoloration.

[0065] Preferably, the solvent is applied using a syringe, such as a disposable needle syringe. This tool allows for precise control of the amount and placement of the solvent. During operation, anhydrous ethanol is precisely applied dropwise to each dot of hot melt adhesive, completely covering the dot and its contact edge with the tortoise shell surface.

[0066] In the physical peeling sub-step, after the anhydrous ethanol has fully softened the hot melt adhesive, that is, after the adhesion between the hot melt adhesive and the surface of the tortoise shell sheet is significantly reduced, peeling can be performed.

[0067] Preferably, the peeling operation is performed using a sharp, thin-edged knife, such as a scalpel. The tip of the knife gently pries the softened hot melt adhesive from the edge, then completely peels it from the surface of the tortoise shell. This operation should be repeated for each hot melt adhesive spot until all temporary fixings are completely removed.

[0068] By performing the above-mentioned curing and removal steps, the structural integrity of the tortoise shell piece is finally restored at the fracture site through the internal permanent adhesive, while the original surface of the outer surface is also completely preserved due to the non-destructive removal of the temporary fixer.

[0069] S5. Archive This step is a follow-up to the restoration work. The restored tortoise shell is photographed from multiple angles using a camera to create an image archive. The tortoise shell is then moved to a specialized warehouse with temperature and humidity control for long-term storage.

[0070] In this embodiment, step S5 is a post-processing step, which serves as the final step of the entire restoration process. Its purpose is to objectively record the results of the restoration work and provide a storage environment for the restored tortoise shell piece that can ensure its long-term stability.

[0071] The post-processing step specifically includes photography archiving operations and storage operations.

[0072] First, perform the photography archiving operation.

[0073] This operation aims to establish a complete and objective imaging and technical archive of the restored tortoise shell. This archive will serve as a direct basis for evaluating the effectiveness of the restoration work and documenting the current state of the artifact.

[0074] Preferably, professional-grade photography equipment is used to capture high-resolution, multi-angle images of the restored tortoise shell under controlled lighting conditions. The images should include not only the full front and back of the tortoise shell, but also close-ups of the repaired seams. The resulting digital images are collated, numbered, and stored to create a digital archive for easy access.

[0075] The establishment of this imaging technical archive has multiple functions: first, it permanently records the precise condition of the tortoise shell after the restoration was completed; second, it can provide basic material for subsequent academic research or exhibition displays; and third, it provides a reliable benchmark for future condition monitoring. By comparing with images taken in the future, any changes that have occurred to the tortoise shell over time can be accurately assessed.

[0076] After the photography file creation operation is completed, execute the storage and saving operation.

[0077] The purpose of this operation is to place the repaired tortoise shell in an environment that can minimize its natural aging process and prevent it from undergoing new physical or chemical deterioration.

[0078] In this embodiment, the storage environment is a professional constant temperature and humidity warehouse. The warehouse is a facility with a sophisticated environmental control system that can maintain the temperature and relative humidity within a preset, narrow fluctuation range for a long period of time.

[0079] Moving the repaired tortoise shell pieces into this constant temperature and humidity warehouse ensures their long-term stability by actively controlling environmental parameters. Constant temperature and humidity effectively inhibit the swelling and contraction of the tortoise shell's primary component (keratin) caused by excessive moisture absorption and dehumidification due to environmental fluctuations, thereby preventing destructive stress on the repaired joints and the tortoise shell itself. This stable environment also helps slow the aging of the primary adhesive (epoxy resin).

[0080] By carrying out this storage and preservation operation, a scientific and controllable long-term preservation condition is provided for the repaired tortoise shell pieces, which is a necessary guarantee for achieving the ultimate goal of cultural relics protection.

[0081] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for repairing tortoise shell, characterized in that: The steps include: S1, applying a first adhesive to the fractured surface of the tortoise shell piece to be repaired, and splicing the fractured portion of the tortoise shell piece; S2, applying a second adhesive to the exterior of the spliced ​​tortoise shell pieces to temporarily fix the tortoise shell pieces; S3. After the first adhesive is cured to form a permanent bond, the second adhesive is removed.

2. A method for repairing tortoise shell according to claim 1, characterized in that: Before S1, it also includes: The tortoise shell piece to be repaired is subjected to a pretreatment step of cleaning and drying.

3. A method for repairing tortoise shell according to claim 2, characterized in that: The pretreatment step specifically includes: using pure water to clean the tortoise shell piece to be repaired, and then naturally drying it.

4. A method for repairing tortoise shell according to claim 1, characterized in that: The first adhesive is an adhesive composition comprising epoxy resin, polyvinyl butyral resin and solvent.

5. A method for repairing tortoise shell according to claim 1, characterized in that: The applying of the first adhesive in S1 is specifically to apply glue on one side of a fracture surface of the tortoise shell piece.

6. A method for repairing tortoise shell according to claim 1, characterized in that: The second adhesive is a hot melt adhesive.

7. A method for repairing tortoise shell according to claim 6, characterized in that: The applying of the second adhesive in S2 is specifically: applying adhesive in a dotted manner on the front and back sides of the tortoise shell pieces along the external cracks formed after the splicing.

8. A method for repairing tortoise shell according to claim 1, characterized in that: The removing of the second adhesive in S3 specifically includes: Using a solvent to soften the second adhesive; The softened second adhesive is physically peeled off.

9. A method for repairing tortoise shell according to claim 8, characterized in that: The solvent is anhydrous ethanol.

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