Adhesive for repairing Betyesian cultural relics, preparation method of adhesive and method for repairing Betyesian cultural relics

Abstract

The invention provides an adhesive for repairing a Betyesian cultural relic, a preparation method of the adhesive and a repairing method of the Betyesian cultural relic, and relates to the technical field of cultural relic repairing. The adhesive for repairing the Betyesian cultural relics comprises the following components in parts by weight: 30-60 parts of a gymnadenia conopsea extract, 5-20 parts of an elm bark extract, 5-20 parts of a gelatin extract, 2-10 parts of a rosin extract, 1-2 parts of a eucommia ulmoides extract and 1-2 parts of a linseed extract. All the components of the adhesive are natural extracts, and the adhesive does not contain harmful substances such as organic solvents, and has the properties of high safety, high bonding strength and good softness and durability.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration technology, and more specifically, to an adhesive for restoring palm-leaf manuscripts, its preparation method, and a method for restoring palm-leaf manuscripts. Background Technology

[0002] The palm tree (Phaedora palmata) is a tropical plant belonging to the palm family (palm family), primarily found in southern regions, particularly India, Sri Lanka, Myanmar, and southwestern China. Palm-leaf manuscripts are classic texts written on palm leaves. Their content mainly consists of Buddhist scriptures and treatises, but also encompasses achievements in ancient Indian literature, astronomy, mathematics, philosophy, and medicine. They are important resources for studying ancient Eastern philosophy, art, history, and culture, and are often referred to as the "panda of Buddhism." Before the advent of paper, palm leaves were one of the primary writing materials in South and Southeast Asian countries, including India, Nepal, Sri Lanka, Myanmar, Thailand, Indonesia, and Cambodia.

[0003] It is worth noting that palm-leaf manuscripts are paper-like artifacts created through artificial processing. They are made from a single natural material, similar in concept to bamboo slips, except that the species from which they are made is different. Unlike paper, which is a composite artificial material made by breaking down plant fibers and then recombining them through papermaking processes, palm-leaf manuscripts retain the leaf itself after processing. The structural and species characteristics of the leaf are not completely destroyed, and biological cells and tissues are still present. For example, palisade tissue, stomata, and veins can be seen in the imaging of palm-leaf manuscript slices.

[0004] Palm leaf manuscripts, as a natural material, are prone to aging and various diseases over time. These diseases can be categorized into diseases affecting the palm leaf itself, diseases affecting the painted surface, and diseases affecting the inscription. Specifically, diseases affecting the palm leaf itself can be classified into three types based on their degree of damage, rate of deterioration, and impact on the preservation of the manuscript: active diseases, stable diseases, and induced diseases (see Table 1 below). In specific restoration work, due to potential overlaps, a comprehensive judgment should be made based on the actual condition of the palm leaf manuscript and the properties listed in the table.

[0005] Table 1

[0006]

[0007] Therefore, protective and restorative interventions are needed to extend the lifespan of palm-leaf manuscripts. However, protection of palm-leaf manuscripts primarily focuses on prevention and preservation, with limited protection and restoration of the manuscript itself. Furthermore, due to their scarcity, there are currently no mature international cases or technical methods. Some related institutions have attempted limited protection and restoration, but these efforts have not been in-depth or developed into standards and systems. Similarly, the adhesives used for restoration are industrial formulations available on the market or in laboratories at the time, lacking specialized restoration and bonding methods.

[0008] The main implementing agencies and technical details worldwide are as follows:

[0009] 1. Types of adhesives used in the British Library: EVA (ethylene-vinyl acetate copolymer), methyl cellulose, wheat starch paste, polyvinyl acetate (PVA), and isinglass (animal-derived). Generally, EVA is mixed with methyl cellulose, or wheat starch paste is mixed with methyl cellulose. Application is simple, achieved by applying with a brush or similar tool.

[0010] 2. The Metropolitan Museum of Art uses the following adhesives: laboratory-grade gelatin, methyl cellulose, isinglass, and wheat starch paste. Generally, gelatin and methyl cellulose are mixed and applied simply using a brush or similar tool.

[0011] The selection of materials for existing adhesives exhibits a coexistence of traditional and modern approaches. Traditional materials are primarily of natural origin, such as starch paste (wheat or rice paste), plant gums (gum arabic, gelatin), and animal glues (fish glue, bone glue). These materials are biodegradable, reversible, safe, and inexpensive. However, firstly, natural materials have significant limitations in their physical properties: starch paste easily absorbs water and swells, leading to mold growth; animal glues, due to their protein content, are prone to attracting insects; and the adhesive strength of plant glues rapidly diminishes in humid environments. Secondly, modern synthetic materials, such as polyvinyl alcohol (PVA) and acrylic emulsions, have significantly improved performance through chemical modification. PVA's molecular chain structure endows it with excellent water resistance and mechanical strength, while acrylic emulsions' fast-drying properties are suitable for efficient operations. However, these materials may release volatile organic compounds (VOCs), posing safety risks when used on palm-leaf manuscript artifacts. Thirdly, the restoration of palm-leaf manuscript artifacts is complex, involving numerous types of damage, varying degrees of severity, and often simultaneous occurrences of overlapping defects. Table 2 shows a comparison of the properties of various adhesives in existing technologies. In this context, besides the core requirements of safety, stability, and reversibility for adhesives, there are also different demands on their physical properties such as viscosity, bond strength, and flexibility. However, existing adhesives cannot meet the actual restoration needs in the restoration of Palmyra manuscripts.

[0012] Table 2 Comparison of Adhesive Properties

[0013]

[0014] In summary, it can be seen that the adhesives currently used in the field of cultural relic protection and restoration for the protection and restoration of physical damage (i.e., active defects) of palm-leaf manuscripts have shortcomings such as insufficient safety, low bonding strength, and inadequate softness and durability. Summary of the Invention

[0015] In order to solve the problems in the prior art, one of the objectives of this application is to provide an adhesive for restoring palm leaf manuscripts, and the adhesive has the properties of strong safety, high bonding strength, good softness and durability.

[0016] According to the first aspect of this application, an adhesive for restoring palm-leaf manuscript artifacts is provided, characterized in that, by weight parts, it comprises: 30-60 parts of palm ginseng extract, 5-20 parts of elm bark extract, 5-20 parts of cow glue extract, 2-10 parts of rosin extract, 1-2 parts of eucommia extract, and 1-2 parts of sesame seed extract.

[0017] Optionally, the preparation method of the palm ginseng extract includes: a) extracting palm ginseng with water at a material-to-liquid ratio of 1:10-30 (g / ml) in a constant temperature water bath at 70-100℃ for 2-4 hours to obtain the palm ginseng extract; the preparation method of the elm bark extract includes: b) extracting elm bark with water at a material-to-liquid ratio of 1:30-60 (g / ml) in a constant temperature water bath at 80-90℃ for 2-4 hours to obtain the elm bark extract; the preparation method of the cow glue extract includes: c) dissolving cow glue with water at a material-to-liquid ratio of 1:2-5 (g / ml) in a constant temperature water bath at 60-75℃. The bovine glue extract is obtained after 3-5 hours; the rosin extract is prepared by: d) bathing rosin in an alkaline aqueous solution at 90-100℃ for 60-100 minutes to obtain the rosin extract; the Eucommia ulmoides extract is prepared by: e) ultrasonically shaking Eucommia ulmoides and water at a material-to-liquid ratio of 1:5-7 (g / ml) at 50-75℃ for 1-2 hours to obtain an aqueous extract of Eucommia ulmoides; the sesame seed extract is prepared by: f) soaking sesame seeds and water at a material-to-liquid ratio of 1:5-10 (g / ml) at 90-95℃ for 2-4 hours to obtain the sesame seed extract.

[0018] Optionally, before step a), the preparation method of the palm ginseng extract further includes purifying and removing impurities from the palm ginseng, specifically including the following steps: soaking the palm ginseng and water in water at a material-to-liquid ratio of 1:1 to 3 (g / ml) for 1 to 3 days, removing the water washing liquid, and then ultrasonically cleaning the palm ginseng for 2 to 5 minutes.

[0019] Optionally, before step b), the method for preparing the elm bark extract further includes: peeling off the inner bark of the elm bark and pulverizing the inner bark; after step b), it further includes: ultrasonically vibrating the elm bark extract for 0.5 to 2 hours to obtain a uniform elm bark extract slurry.

[0020] Optionally, before step c), the method for preparing the bovine glue extract further includes: soaking solid bovine glue and water in water at a ratio of 1:1 to 2 (g / ml) for 5 to 10 hours until the bovine glue swells; after step c), the method for preparing the bovine glue extract further includes: ultrasonically vibrating the bovine glue extract at 40 to 60°C for 0.5 to 2 hours to obtain a uniform bovine glue extract solution.

[0021] Optionally, the preparation method of the rosin extract specifically includes the following steps: weighing rosin and pulverizing it; weighing solid alkali at a rosin:alkali mass ratio of 9-11:1; measuring water at a rosin:water material-liquid ratio of 7-9:20 (g / ml); dissolving the alkali in water to obtain an alkali-water solution; heating the alkali-water solution to 90-100°C; and bathing the rosin in the alkali-water solution in a water bath for 60-100 minutes to obtain rosin resin; adding the rosin resin to water at a material-liquid ratio of 1:20-30 (g / ml) and diluting it with a high-speed mixer to obtain the rosin extract; wherein the alkali is sodium bicarbonate.

[0022] Optionally, before step e), the preparation method of the Eucommia ulmoides extract further includes: ultra-fine pulverizing the Eucommia ulmoides bark; after step e), the preparation method of the Eucommia ulmoides extract further includes: passing the aqueous extract of Eucommia ulmoides through a 1000-mesh, 500-mesh and 100-mesh sieve successively at 40-60°C to obtain a filtrate, allowing the filtrate to stand at 5-15°C to precipitate the colloid, thereby obtaining the Eucommia ulmoides extract.

[0023] Optionally, before step f), the method for preparing the sesame seed extract further includes: purifying and drying the sesame seeds.

[0024] According to a second aspect of this application, a method for preparing an adhesive for restoring palm-leaf manuscript artifacts is provided, comprising mixing the palm extract, elm bark extract, cow glue extract, rosin extract, eucommia extract and sesame seed extract described in the first aspect of this application in a specified ratio to obtain the adhesive.

[0025] According to a third aspect of this application, a method for restoring palm-leaf manuscript artifacts is provided. For damaged or broken palm-leaf manuscript artifacts, the restoration method includes: taking a palm-leaf manuscript, applying an adhesive according to the first aspect of this application or an adhesive prepared according to the preparation method described in the second aspect of this application to the surface of the palm-leaf manuscript to be restored and the surface of the restoration material, respectively, with the adhesive coating thickness being 5-10 mm, followed by curing and drying; wherein, the restoration material is a Yunnan palm-leaf manuscript; or for palm-leaf manuscript artifacts with warped edges, the restoration method includes: taking a palm-leaf manuscript, applying an adhesive according to the first aspect of this application or an adhesive prepared according to the preparation method described in the second aspect of this application to the surface of the palm-leaf manuscript to be restored, with the adhesive coating thickness being 5-10 mm, followed by curing and drying.

[0026] The technical solution adopted in this invention can achieve the following beneficial effects:

[0027] This invention provides an adhesive specifically for repairing palm-leaf manuscripts, exhibiting excellent repair effects on physical damage to the manuscript itself (e.g., fiber delamination and warping, defects, cracks, etc.). Furthermore, the adhesive is pale yellow (as is the natural color of palm-leaf manuscript artifacts), leaving no obvious repair marks after restoration. This adhesive possesses strong safety, high bonding strength, and excellent flexibility and durability. The adhesive provided by this invention utilizes natural, non-toxic plant extracts, with ginseng, elm bark, cow glue, rosin, eucommia, and sesame seeds as raw materials, forming a natural material composite system. In this adhesive, ginseng extract and elm bark extract provide basic adhesion; cow glue (animal glue) extract enhances cohesion; sesame seed extract and eucommia extract act as additives to adjust the adhesive's bonding strength, softness, and viscosity; and rosin extract acts as a modifier to adjust rheological properties. The synergistic effect of these materials is significant. Physically, the flexibility of the plant glue buffers the stress generated by the drying shrinkage of the palm-leaf manuscript, while the rigidity of the animal glue ensures structural stability. From the perspective of the inherent properties of natural materials, rosin extract possesses anti-corrosion, anti-mildew, and insect-repellent effects, effectively avoiding the instability risks associated with natural materials. The adhesive provided in this application meets the core requirements of safety, stability, and reversibility for cultural relic restoration materials. Furthermore, the adhesive's viscosity can be dynamically adjusted according to the type and severity of the damage. Compared to existing palm leaf restoration adhesives, this method is safer and more reversible, and can be flexibly adjusted according to actual usage needs, thus better aligning with the principles of cultural relic protection and restoration. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0029] According to one embodiment of this application, an adhesive for repairing palm-leaf manuscript artifacts is provided, comprising, by weight: 30-60 parts of palm ginseng extract, 5-20 parts of elm bark extract, 5-20 parts of cow glue extract, 2-10 parts of rosin extract, 1-2 parts of eucommia extract, and 1-2 parts of sesame seed extract. For example, in the adhesive of this application, the weight parts of the palm ginseng extract can be 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 parts or any value of these values; the weight parts of the elm bark extract can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts. The weight parts of the extract can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts, or any of these values; the weight parts of the extract can be 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts, or any of these values; the weight parts of the extract can be 1, 1.5, or 2 parts, or any of these values; the weight parts of the extract can be 1, 1.5, or 2 parts, or any of these values.

[0030] In this embodiment, the raw material involved, Gymnadenia conopsea (L.) R.Br., also known as hand ginseng, palm ginseng, hand ginseng, or Buddha's hand ginseng, is the tuberous root of the orchid Gymnadenia conopsea or Gymnadenia gracilis. It is a rare medicinal material from the Qinghai-Tibet Plateau, growing in alpine shrublands at an altitude of 3,000-4,000 meters. It is named for its palm-like shape and is mainly used in medicine. It is a medicinal plant.

[0031] Elm bark is the dried bark or root bark of the elm tree (Ulmus pumila L.), a plant in the elm family. It can be used medicinally and has diuretic, urinary tract drier, and anti-swelling effects. The elm is a deciduous tree that can grow up to 25 meters tall. It has an upright trunk, many spreading branches, and a nearly spherical or oval crown. The bark is dark gray, rough, and irregularly longitudinally fissured.

[0032] Niujiao is cowhide glue, and its main component is gelatin protein. It is a gelatinous substance made by boiling cowhide.

[0033] Rosin (Colophonium), also known as pine resin, pine gum, pine tar, or raw rosin, is a non-volatile natural resin obtained from pine resin through various processing methods. Rosin is an important chemical raw material, widely used in industries such as soap, papermaking, paint, and rubber.

[0034] Eucommia ulmoides Oliver, also known as eucommia bark, is a plant belonging to the Eucommiaceae family. Medicinal Eucommia refers to the dried bark of the Eucommia ulmoides tree, a valuable tonic in China.

[0035] Sesame seeds are the dried, mature seeds of flax (Lium usitatissimum L.), a plant belonging to the Linaceae family. The original plant was an annual herb, but all varieties are now cultivated.

[0036] In one embodiment, the preparation method of the *Gynostemma pentaphyllum* extract includes: a) extracting *Gynostemma pentaphyllum* with water at a material-to-liquid ratio of 1:10-30 (g / ml) in a constant temperature water bath at 70-100°C for 2-4 hours to obtain the *Gynostemma pentaphyllum* extract; preferably, in another embodiment, the preparation method of the *Gynostemma pentaphyllum* extract includes: a-1) soaking *Gynostemma pentaphyllum* with water at a material-to-liquid ratio of 1:1-3 (g / ml) in water for 1-3 days to remove impurities such as mud from the *Gynostemma pentaphyllum*, removing the washing liquid, and then ultrasonically cleaning the *Gynostemma pentaphyllum* for 2-5 minutes; a) extracting the cleaned *Gynostemma pentaphyllum* with water at a material-to-liquid ratio of 1:10-30 (g / ml) in a constant temperature water bath at 70-100°C for 2-4 hours, preferably at 90°C for 3 hours, and removing all the light milky white uniform gelatinous substance, which is the *Gynostemma pentaphyllum* extract. In the above embodiments, the material-to-liquid ratio of *Gynostemma pentaphyllum* with water refers to the ratio between the mass of *Gynostemma pentaphyllum* and the volume of water, in g / ml. For example, in step a-1) for purification and impurity removal, the ratio of palm to water can be 1:1, 1:2, 1:3 g / ml or any value between these values; in step a) for extracting plant gum, the ratio of palm to water can be 1:10, 1:15, 1:20, 1:25, 1:30 g / ml or any value between these values, the temperature for extraction in a constant temperature water bath can be 70, 80, 90, 100℃ or any value between these values, and the extraction time can be 2, 3, 4 hours or any value between these values.

[0037] In the context of this application, those skilled in the art should understand that the “water” used can be distilled water, tap water, mineral water, deionized water, etc., with distilled water being preferred; the “material-liquid ratio” mentioned refers to the ratio between the mass of the material and the volume of the liquid (g / ml).

[0038] In one embodiment, the preparation method of the elm bark extract includes: b) extracting elm bark and water at a material-to-liquid ratio of 1:30-60 (g / ml) in a constant temperature water bath at 80-90°C for 2-4 hours to obtain the elm bark extract. Considering that elm bark consists of inner bark and outer bark, and most of the plant gum components are found in the inner bark, from the perspective of improving the extraction rate of plant gums, it is preferable to use the inner bark of elm bark. In a preferred embodiment, the preparation method of the elm bark extract includes: b-1) peeling the inner bark of the elm tree and pulverizing the inner bark, for example, cutting the inner bark into 5-10cm strips or small pieces and placing them in a gauze bag for subsequent extraction; b) extracting the elm bark and water at a material-to-liquid ratio of 1:30-60 (g / ml) in a constant temperature water bath at 80-90°C for 2-4 hours, preferably at 85°C for 3 hours. The elm bark extract obtained in this step is a non-homogeneous solution containing colloids and water; then proceeding to step b+1): ultrasonically vibrating the elm bark extract from step b) for 0.5-2 hours, preferably for 1 hour, to fully integrate the colloids, and removing all the pale yellow homogeneous colloids to obtain a homogeneous colloid of elm bark extract. In the above embodiment, the material-to-liquid ratio of elm bark to water refers to the ratio between the mass of elm bark and the volume of water (g / ml). For example, in step b) of extracting plant gum, the ratio of elm bark to water can be 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60 g / ml or any value between these values, the extraction temperature in the constant temperature water bath can be 80, 85, 90℃ or any value between these values, and the extraction time can be 2, 3, 4 hours or any value between these values.

[0039] Palm ginseng extract and elm bark extract are plant-based adhesives. As a basic adhesive source, their main components are natural polysaccharides (such as cellulose and galactose). The molecular chains form a flexible network structure through hydrogen bonds and van der Waals forces, which gives the adhesive initial bonding strength and good flexibility. It can adapt to the shrinkage and deformation of palm leaves during the drying process and reduce the risk of cracking caused by stress concentration.

[0040] In one embodiment, the preparation method of the bovine glue extract includes: c) dissolving bovine glue and water at a material-to-liquid ratio of 1:2-5 (g / ml) in a constant temperature water bath at 60-75°C for 3-5 hours to obtain the bovine glue extract. In a preferred embodiment, the preparation method of the bovine glue extract includes: step c-1): soaking solid bovine glue in water at a material-to-liquid ratio of 1:1-2 (g / ml) for 5-10 hours until the bovine glue swells. In this step, soaking the bovine glue in water to ensure full swelling facilitates the complete dissolution of the colloidal components in the subsequent extraction step, thereby improving extraction efficiency; then proceeding to step c): retaining the aqueous solution from step c-1), adding water as needed, and dissolving the bovine glue and water at a material-to-liquid ratio of 1:2-5 (g / ml) in a constant temperature water bath at 60-75°C for 3-5 hours to obtain the bovine glue extract; next, proceeding to step c+1): ultrasonically vibrating the bovine glue extract at 40-60°C for 0.5-2 hours to fully fuse the glue solution into a uniform colloidal solution. Taking out all the uniform glue solution yields a uniform bovine glue extract solution. In the above embodiment, the material-to-liquid ratio of bovine glue to water refers to the ratio between the mass of bovine glue and the volume of water (g / ml). For example, in step c), the ratio of bovine glue to water can be 1:2, 1:3, 1:4, 1:5 g / ml or any value between these values; the temperature for extraction or dissolution in a constant temperature water bath can be 60, 65, 70, 75℃ or any value between these values; and the extraction time can be 3, 4, 5 hours or any value between these values. In this application, the bovine glue (animal glue) extract uses collagen as its main component. Its molecular structure contains a large number of polar groups (such as amino and carboxyl groups), which form strong interactions (such as hydrogen bonds and ionic bonds) with the polysaccharide chains of plant glue. This significantly enhances the cohesiveness and rigidity of the adhesive, ensuring the mechanical stability of the repaired structure and avoiding insufficient bonding strength caused by the excessive flexibility of plant glue.

[0041] The preparation method of the rosin extract includes: d) bathing rosin in an alkaline aqueous solution at 90-100°C for 60-100 minutes to obtain the rosin extract. In a more specific embodiment, the preparation method of the rosin extract includes the following steps: weighing rosin and pulverizing it, for example, crushing the rosin into small pieces using a mortar and pestle, such that the mass of the small pieces is less than or equal to 5g; weighing a solid alkali at a rosin:alkali mass ratio of 9-11:1, for example using sodium bicarbonate (sodium baking soda) as the solid alkali; measuring a certain amount of water at a rosin:water material-liquid ratio of 7-9:20 (g / ml); dissolving the alkali in water to obtain an alkaline aqueous solution, heating the alkaline aqueous solution to 90-100°C, and bathing the rosin in the alkaline aqueous solution for 60-100 minutes to obtain rosin resin; adding the rosin resin to water at a material-liquid ratio of 1:20-30 (g / ml) and diluting it with a high-speed mixer, and taking all the light yellow resin to obtain the rosin extract. The chemical composition of rosin is quite complex; its common molecular formula is C64-C ... 19 H 29 COOH is mainly composed of abietic acid and piperic acid. The purpose of adding an alkaline aqueous solution (sodium bicarbonate aqueous solution) to the rosin is to saponify the rosin. This is mainly because abietic acid is originally a weakly polar molecule, but after saponification, it is transformed into an ionic surfactant (rosin soap), which significantly improves its hydrophilicity and compatibility with other polar components in the adhesive. Furthermore, as a tackifying resin, rosin soap can reduce the interfacial tension between the adhesive and the adherend (such as beech leaf), enhance wettability and contact area, and can also act as a modifier to adjust rheological properties and improve initial tack.

[0042] In one embodiment, the preparation method of the Eucommia ulmoides extract includes: e) ultrasonically vibrating Eucommia ulmoides and water at a material-to-liquid ratio of 1:5-7 (g / ml) at 50-75°C for 1-2 hours to obtain an aqueous extract of Eucommia ulmoides. The aqueous extract contains sawdust from Eucommia ulmoides itself. To improve the binding effect, impurities, including sawdust, can be further removed from the aqueous extract. In a preferred embodiment, the preparation method of the Eucommia ulmoides extract includes the following steps: e-1) firstly, ultra-finely pulverizing the Eucommia ulmoides bark. For example, pulverize into thin strips 3-5 cm in length; e) mix Eucommia ulmoides and water at a material-to-liquid ratio of 1:5-7 (g / ml) and sonicate at 50-75°C for 1-2 hours to obtain an aqueous extract of Eucommia ulmoides; e+1) pass the aqueous extract of Eucommia ulmoides through 1000 mesh, 500 mesh and 100 mesh sieves at 40-60°C to remove impurities and obtain a filtrate. At this time, the filtrate is a colloidal solution. Let the filtrate stand at 5-15°C to precipitate the colloid. Take out all the precipitated colloid to obtain the Eucommia ulmoides extract.

[0043] In one embodiment, the method for preparing the sesame seed extract includes: f) soaking sesame seeds and water at a material-to-liquid ratio of 1:5-10 (g / ml) at 90-95°C for 2-4 hours to obtain the sesame seed extract. In a preferred embodiment, the method for preparing the sesame seed extract includes: f-1) purifying and drying the sesame seeds, for example, by ultrasonically cleaning the sesame seeds for 3 minutes to remove impurities, and then draining the water; f) soaking the purified sesame seeds and water at a material-to-liquid ratio of 1:5-10 (g / ml) at 90-95°C for 2-4 hours, and taking out all the homogeneous gel to obtain the sesame seed extract.

[0044] According to one embodiment of this application, a method for preparing an adhesive for repairing palm-leaf manuscript artifacts is provided. The preparation method includes uniformly mixing *Gynostemma pentaphyllum* extract, *Elm bark* extract, *Ox glue* extract, rosin extract, *Eucommia ulmoides* extract, and sesame seed extract prepared by the above methods according to a specified ratio. Specifically, by weight, 30-60 parts of *Gynostemma pentaphyllum* extract, 5-20 parts of *Elm bark* extract, 5-20 parts of *Ox glue* extract, 2-10 parts of rosin extract, 1-2 parts of *Eucommia ulmoides* extract, and 1-2 parts of sesame seed extract are mixed uniformly to obtain the adhesive. The adhesive prepared by this method has a pale yellow appearance, which is also the color of the palm-leaf manuscript artifacts. Therefore, no obvious repair marks will be left after repair. Because the adhesive provided by this invention uses natural and non-toxic plant extracts, all components are natural extracts and do not contain harmful substances such as organic solvents, chemical corrosion of the palm-leaf manuscript artifacts is avoided, resulting in high safety.

[0045] According to another embodiment of this application, a method for restoring palm-leaf manuscript artifacts is provided, wherein the restoration method varies depending on the extent of damage to the palm-leaf manuscript artifact. For example, for palm-leaf manuscript artifacts that are incomplete or broken, especially those with severe breakage, adhesive alone is insufficient; usually, Yunnan palm-leaf manuscripts are needed for filling and repair, i.e., Yunnan palm-leaf manuscripts are used as the repair material. In this case, the restoration method for the palm-leaf manuscript artifact includes: taking a palm-leaf manuscript, applying the aforementioned adhesive to both the surface of the palm-leaf manuscript to be repaired and the surface of the repair material (i.e., the Yunnan palm-leaf manuscript), with the adhesive coating thickness being 5-10 mm, and then allowing it to cure and dry. For palm-leaf manuscript artifacts that are warped or have very small area cracks, the damage is relatively minor, and adhesive alone can solve the problem. In this case, the restoration method includes: taking a palm-leaf manuscript, applying the aforementioned adhesive to the surface of the palm-leaf manuscript to be repaired, with the adhesive coating thickness being 5-10 mm, and then allowing it to cure and dry. In the above methods, curing and drying are usually carried out by pressure drying, for example, pressing a paper stone onto the repaired palm leaf and waiting for the adhesive to dry completely.

[0046] The adhesive for restoring palm-leaf manuscript artifacts provided by the present invention, its preparation method, and the restoration method for palm-leaf manuscript artifacts are further described below with reference to embodiments. All raw materials involved in the embodiments can be obtained through conventional means and comply with relevant national standards.

[0047] Preparation of adhesives in Examples 1-3

[0048] Preparation of palm ginseng extract:

[0049] 1. Soak your palm in distilled water at a ratio of 1:2 (g / ml) for 3 days;

[0050] 2. After removing the washing solution, ultrasonically clean all the soaked ginseng palms for 3 minutes;

[0051] 3. Extract the palm ginseng with distilled water at a ratio of 1:20 (g / ml) in a constant temperature water bath at 90℃ for 3 hours. Take out all the light milky white uniform gelatinous substance to obtain the palm ginseng extract.

[0052] Preparation of elm bark extract:

[0053] 1. Peel off the inner bark of the elm tree, cut the inner bark into 5-10cm strips or small pieces and put them into a gauze bag;

[0054] 2. Soak elm bark in distilled water at a ratio of 1:45 (g / ml) in a constant temperature water bath at 85℃ for 3 hours;

[0055] 3. The elm bark extract obtained in step 2 is ultrasonically vibrated for 1 hour to fully fuse the colloid. All the pale yellow, uniform colloid is then removed to obtain the elm bark extract.

[0056] Preparation of bovine gelatin extract:

[0057] 1. Take solid cow glue and distilled water and soak them in distilled water at a material-to-liquid ratio of 1:2 (g / ml) for 8 hours until the cow glue swells;

[0058] 2. Retain the aqueous solution from step 1, and continue to add distilled water, so that the glue and distilled water are dissolved in a constant temperature water bath at 70°C for 4 hours at a material-to-liquid ratio of 1:4 (g / ml);

[0059] 3. The bovine glue extract from step 2 is ultrasonically vibrated at 45°C for 1 hour to fully fuse the glue solution and form a uniform colloidal solution. All the uniform glue solution is taken out to obtain a uniform bovine glue extract solution.

[0060] Preparation of rosin extract:

[0061] 1. Weigh out the rosin and crush it into small pieces using a mortar and pestle, so that the mass of each small piece is less than or equal to 5g;

[0062] 2. Weigh out sodium bicarbonate as solid alkali according to a rosin:alkali mass ratio of 10:1;

[0063] 3. Measure a certain amount of water according to the ratio of rosin to distilled water of 9:20 (g / ml);

[0064] 4. Dissolve the alkali in distilled water by heating it to 80°C to obtain an alkali solution;

[0065] 5. Continue heating the alkaline solution to 100°C and extract the rosin in the alkaline solution for 80 minutes;

[0066] 6. After boiling, the gelatin is a brownish-black viscous substance. Distilled water is added at a ratio of 1:25 (g / ml) and diluted with a high-speed mixer. All the light yellow gelatin liquid is taken out to obtain rosin extract.

[0067] Preparation of Eucommia ulmoides extract:

[0068] 1. After washing and drying the Eucommia bark in clean water, pulverize it into flocculent material (3-5cm long strips);

[0069] 2. Eucommia bark and distilled water were ultrasonically shaken at 60℃ for 2 hours at a material-to-liquid ratio of 1:6 (g / ml) to obtain an aqueous extract of Eucommia bark;

[0070] 3. Pass the aqueous extract of Eucommia ulmoides through 1000 mesh, 500 mesh and 100 mesh sieves in sequence at 50℃ to remove impurities in the aqueous extract and obtain the filtrate, which is a colloidal solution at this time;

[0071] 4. Allow the filtrate to stand at 10°C for 2 hours, allowing colloidal precipitate to form. Remove all the precipitated colloid to obtain Eucommia ulmoides extract.

[0072] Preparation of sesame seed extract:

[0073] 1. Clean the sesame seeds with ultrasonic cleaner for 3 minutes to remove impurities, then drain the water;

[0074] 2. The purified sesame seeds and distilled water were extracted in a water bath at 95°C for 2 hours at a material-to-liquid ratio of 1:8 (g / ml). All the homogeneous gel was then removed to obtain the sesame seed extract.

[0075] In Examples 1-3, adhesives were prepared according to the raw material composition ratios (by weight) shown in Table 3.

[0076] Table 3

[0077] raw material Example 1 Example 2 Example 3 Palm ginseng extract 55 50 60 Elm bark extract 15 20 10 bovine gelatin extract 20 20 10 pine extract 7 8 6 Eucommia extract 2 1 2 Sesame seed extract 1 1 2

[0078] The specific preparation method is as follows: weigh each extract according to the ratio in Table 3, mix all the extracts, and prepare the adhesives described in Examples 1 to 3 respectively.

[0079] Comparative Example 1: The preparation of the adhesive was exactly the same as in Example 1, except that the amount of palm ginseng extract was 20 parts by weight.

[0080] Comparative Example 2: The preparation of the adhesive was exactly the same as that in Example 1, except that the elm bark extract was 3 parts by weight.

[0081] Comparative Example 3: The preparation of the adhesive was exactly the same as that in Example 1, except that the amount of bovine glue extract was 3 parts by weight.

[0082] Comparative Example 4: The preparation of the adhesive was exactly the same as that in Example 1, except that the rosin extract was 1 part by weight.

[0083] Comparative Example 5: The preparation of the adhesive was exactly the same as that in Example 1, except that Eucommia ulmoides extract and sesame seed extract were not added.

[0084] Example 4: Methods for Restoring Palm-Leaf Manuscripts

[0085] Three diseases—fiber delamination and warping, defects, and cracks—were simulated on Yunnan palm leaves, and the adhesives prepared in Examples 1-3 were used to repair the Yunnan palm leaves.

[0086] When the leaves of the palm exhibit fiber delamination and warping, the specific repair method is as follows:

[0087] 1. Apply adhesive. Take the diseased palm leaf as the palm leaf to be repaired. Apply a layer of the adhesive prepared in Examples 1 to 3 to the surface of the delaminated and curled part of the palm leaf to be repaired. The application instrument is a double-ended brush, one end of which is nylon bristle and the other end is an agate roller. The size of the nylon bristle brush head varies depending on the repair area. The thickness of the adhesive applied is 5-10 mm.

[0088] 2. After applying the coating, use an agate roller to press the raised parts back into their original position.

[0089] 3. Drying and curing. Press the paper-pressing stone onto the repaired palm leaf, cure at 20±5℃ and 20±10% RH for 3-7 hours, and wait for the adhesive to dry completely in the shade.

[0090] When a palm leaf is damaged or broken (the damaged or broken area is ≤10%-90% of the whole palm leaf), the specific repair method is as follows:

[0091] 1. Prepare intact Yunnan palm leaf manuscripts as restoration materials.

[0092] 2. Apply adhesive. Take the diseased palm leaves as the palm leaf to be repaired. Apply a layer of the adhesive prepared in Examples 1 to 3 to the surface of the palm leaf to be repaired and the surface of the repair material in step 1. The application instrument is a double-ended pen, one end of which is nylon bristles and the other end is an agate roller. The size of the nylon bristle pen tip varies depending on the repair area. The thickness of the adhesive applied is 5-10 mm.

[0093] 3. Apply the repair material to the damaged area of ​​the palm leaf to be repaired to form a seamless connection.

[0094] 4. Drying and curing. Press the paper-pressing stone onto the repaired palm leaf, cure at 20±5℃ and 20±10% RH for 3-7 hours, and wait for the adhesive to dry completely in the shade.

[0095] Results of palm leaf restoration:

[0096] A. Repair of fiber delamination and warping

[0097] Before repair, it was observed that the palm leaf manuscript had fibers that were delaminated and curled up, which not only affected its preservation but could also lead to further damage. After repair, the delaminated and curled fibers were well reattached, and the text was clearly visible, indicating that the adhesives prepared in Examples 1-3 of this application can provide sufficient adhesive force to address the problem of fiber delamination and curling up, thus restoring the stability of the palm leaf manuscript structure.

[0098] B. Repair of large-area defects

[0099] Before repair, the palm leaf had significant large-area defects, severely affecting its integrity and appearance. After repair, the defects were effectively filled, the surface of the palm leaf was restored to a smooth state, and the overall visual effect was greatly improved, demonstrating the excellent filling and bonding ability of the adhesives prepared in Examples 1-3 of this application in repairing large-area defects.

[0100] C. Repair of small-area cracks and defects

[0101] Before repair, the palm leaf had small areas of cracks and defects, affecting its integrity. After repair, these small areas of damage were properly repaired, and the surface of the palm leaf was basically restored to its original integrity. The adhesives prepared in Examples 1 to 3 of this application also showed good fine repair capabilities in small area repair, and could accurately bond and fill the damaged parts.

[0102] Performance tests of the adhesives in Examples 1-3 and Comparative Examples 1-5:

[0103] Objective: To evaluate the degradation of adhesive bonding performance under sustained stress and different environments, and to compare the performance differences of adhesives with different formulations in Examples 1-3 and Comparative Examples 1-5.

[0104] Evaluation indicators: bond strength, flexibility and durability; test methods are shown in Table 4.

[0105] Table 4

[0106]

[0107] The test results are shown in Table 5.

[0108] Table 5

[0109]

[0110] As shown in Table 5, the adhesives in Examples 1-3 consistently met the requirements for bond strength, softness, and durability, demonstrating good bond strength, softness, and durability. In contrast, the adhesives in Comparative Examples 1-5 failed to meet the requirements for these three indicators, failing to simultaneously possess good bond strength, softness, and durability, thus exhibiting certain performance differences compared to the adhesives in Examples 1-3.

[0111] In summary, this invention provides an adhesive prepared from natural, non-toxic plants, using ginseng, elm bark, cow glue, rosin, eucommia, and sesame seeds as raw materials. All components are natural extracts, free of organic solvents and other harmful substances. This adhesive exhibits strong safety, high bonding strength, good flexibility, and excellent durability (resistant to mold growth under high humidity conditions). Compared to existing palm leaf restoration adhesives, this method is safer and more reversible, and can be flexibly adjusted according to actual usage needs, better aligning with the principles of cultural relic protection and restoration.

[0112] The embodiments of this application have been described above, but this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An adhesive for restoring palm-leaf manuscript artifacts, characterized in that, By weight, including: The extracts consist of 30-60 parts of ginseng extract, 5-20 parts of elm bark extract, 5-20 parts of cow glue extract, 2-10 parts of rosin extract, 1-2 parts of eucommia bark extract, and 1-2 parts of sesame seed extract.

2. The adhesive according to claim 1, characterized in that, The preparation method of the palm ginseng extract includes: a) soaking palm ginseng and water at a material-to-liquid ratio of 1:10-30 (g / ml) at 70-100℃ for 2-4 hours to obtain the palm ginseng extract; The preparation method of the elm bark extract includes: b) soaking elm bark and water at a material-to-liquid ratio of 1:30-60 (g / ml) at 80-90℃ for 2-4 hours to obtain the elm bark extract; The preparation method of the bovine glue extract includes: c) soaking bovine glue and water at a material-to-liquid ratio of 1:2-5 (g / ml) at 60-75°C for 3-5 hours to obtain the bovine glue extract; The preparation method of the rosin extract includes: d) bathing rosin in an alkaline aqueous solution at 90-100°C for 60-100 minutes to obtain the rosin extract; The preparation method of the Eucommia ulmoides extract includes: e) ultrasonically shaking Eucommia ulmoides and water at a material-to-liquid ratio of 1:5-7 (g / ml) at 50-75℃ for 1-2 hours to obtain an aqueous extract of Eucommia ulmoides; The preparation method of the sesame seed extract includes: f) soaking sesame seeds and water at a material-to-liquid ratio of 1:5-10 (g / ml) at 90-95°C for 2-4 hours to obtain the sesame seed extract.

3. The adhesive according to claim 2, characterized in that, Before step a), the preparation method of the palm ginseng extract further includes purifying and removing impurities from the palm ginseng, specifically including the following steps: Soak the palm and water in water at a ratio of 1:1 to 3 (g / ml) for 1 to 3 days. After removing the water, ultrasonically clean the palm and water for 2 to 5 minutes.

4. The adhesive according to claim 2, characterized in that, Before step b), the method for preparing the elm bark extract further includes: peeling off the inner bark of the elm bark and pulverizing the inner bark; After step b), the method further includes: ultrasonically vibrating the elm bark extract for 0.5 to 2 hours to obtain a uniform elm bark extract solution.

5. The adhesive according to claim 2, characterized in that, Before step c), the preparation method of the bovine glue extract further includes: taking solid bovine glue and water at a material-to-liquid ratio of 1:1 to 2 (g / ml) and soaking it in water for 5 to 10 hours until the bovine glue swells; After step c), the preparation method of the bovine glue extract further includes: ultrasonically vibrating the bovine glue extract at 40-60°C for 0.5-2 hours to obtain a uniform bovine glue extract solution.

6. The adhesive according to claim 2, characterized in that, The preparation method of the rosin extract specifically includes the following steps: Weigh out the rosin and grind it into powder; Weigh out solid alkali in a rosin:alkali mass ratio of 9 to 11:1; Measure water at a ratio of rosin to water of 7-9:20 (g / ml); The alkali is dissolved in water to obtain an alkaline aqueous solution, and the alkaline aqueous solution is heated to 90-100°C. The rosin is then placed in the alkaline aqueous solution in a water bath for 60-100 minutes to obtain rosin resin. The rosin resin was added to water at a ratio of 1:20-30 (g / ml) and diluted with a mixer to obtain the rosin extract. The alkali is sodium bicarbonate.

7. The adhesive according to claim 2, characterized in that, Before step e), the method for preparing the Eucommia ulmoides extract further includes: ultra-fine pulverizing the Eucommia ulmoides bark; After step e), the preparation method of the Eucommia ulmoides extract further includes: passing the aqueous extract of Eucommia ulmoides through a 1000-mesh, 500-mesh and 100-mesh sieve at 40-60°C to obtain a filtrate, allowing the filtrate to stand at 5-15°C to precipitate the colloid and obtain the Eucommia ulmoides extract.

8. The adhesive according to claim 2, characterized in that, Before step f), the method for preparing the sesame seed extract further includes: purifying and drying the sesame seeds.

9. A method for preparing an adhesive for restoring palm-leaf manuscript artifacts, characterized in that, The adhesive is obtained by uniformly mixing the palm extract, elm bark extract, bovine glue extract, rosin extract, eucommia extract and sesame seed extract according to any one of claims 1 to 8 in a specified ratio.

10. A method for restoring palm-leaf manuscript artifacts, characterized in that, For damaged or broken palm-leaf manuscripts, the restoration method includes: taking a palm-leaf manuscript, applying the adhesive according to any one of claims 1 to 8 or the adhesive prepared according to the preparation method of claim 9 to the surface of the palm-leaf manuscript to be restored and the surface of the restoration material, respectively, followed by curing and drying; or For palm leaf manuscripts that are warped, the repair method includes: taking a palm leaf manuscript, applying an adhesive according to any one of claims 1 to 8 or an adhesive prepared according to the preparation method of claim 9 to the surface of the palm leaf manuscript to be repaired, and then curing and drying it.

Images