JP6189902B2 - Method to remove whitened synthetic resin from the surface of cultural assets - Google Patents

Description

  The present invention relates to a method for removing a whitened synthetic resin from the surface of a cultural property, and more specifically, in the state of a solution or dispersion for preserving or restoring a cultural property having a surface on which a coating film is formed. The present invention relates to a method for removing a whitened synthetic resin that is applied to a cultural property and exposed on the surface of the cultural property.

  In order to preserve and restore the surface of cultural properties, especially the surfaces of cultural properties with decoration, painting, ink brushes, etc., together with experts with advanced skills, materials suitable for preservation and restoration of coatings are available. Needed. One of the required materials is an anti-slipping material for preventing or repairing peeling and breakage of the coating film. This material is also used for preventing or repairing dropping or damage of a base made of board, paper or other fragile and susceptible material. Traditionally, traditional adhesives typified by glue, sediment, bean juice and agar have been used to prevent peeling, but since the 1940s, polyvinyl alcohol (hereinafter referred to as “PVA”), water-soluble acrylic resin, etc. The synthetic resin has been used. Synthetic resins rapidly spread as adhesives for cultural property restoration after the war due to the advantages such as easy handling and high permeability and the reduction of the production scale of traditional adhesives.

  However, in recent years, there have been many reports of cases in which the synthetic resin on the surface of cultural properties gradually faded due to secular change, and the original value of the cultural properties was impaired. “Damage” in which famous murals and barrier paintings in various places appear white due to whitened synthetic resin has been taken up by some news organizations (for example, NHK News on February 19, 2011 “Synthesis that spreads to cultural assets” Pursuing resin damage "), it is becoming a social problem. Synthetic resins have been used not only for painting murals and barrier paintings, but also for strengthening the surface of scriptures, scrolls, and so on. It is a problem in inheriting.

  Unlike traditional adhesives such as glue, whitened synthetic resin is not easy to remove even if supplemented with liquids such as water. For example, even if water is added to PVA that has been whitened due to secular change, PVA does not swell at all or gels and swells slightly. If the PVA in this state is forcibly peeled off, the underlying coating film will be damaged. Non-Patent Document 1 reports a case in which PVA that had been gelled with moisture was lifted off with tweezers and peeled off, and the underlying coating film peeled off, forcing the PVA removal operation to cease. Yes.

  Under such circumstances, development of a technique for removing the whitened synthetic resin from the surface of the cultural property without damaging the cultural property is in progress. For example, Patent Document 1 discloses a technique for decomposing and removing PVA using an enzyme composition containing an enzyme that oxidizes PVA and an enzyme that hydrolyzes oxidized PVA, with regard to PVA removal. .

JP 2013-116959 A

Taro Okaiwa, "Synthetic Resins in Performance", National Museum of Ethnology Research Report, Volume 36, February 28, 2003, p.93-101

  However, in order to decompose a whitened synthetic resin using an enzyme, it is necessary to prepare a plurality of enzymes (for example, an oxidase and a hydrolase), and the enzyme composition is prepared at a temperature suitable for the expression of the enzyme activity. It is also necessary to contact the surface of the cultural property for a certain period of time. For this reason, the decomposition technique using an enzyme has a problem that its preparation and on-site implementation are complicated.

  In view of the above situation, an object of the present invention is to provide a novel method suitable for easily removing a synthetic resin whitened while being exposed on the surface of a cultural property without damaging the cultural property. And

  When the surface of the whitened synthetic resin was magnified and observed using a microscope, it was found that the whitened synthetic resin was transformed into fine particles. The synthetic resin applied in the state of a solution or the like was in the form of a continuous film when applied, but then gradually dried and shrunk, resulting in a change to dense or separated fine particles, It is thought that the appearance of whitening was caused by irregular reflection of light. The inventor has completed the present invention based on this discovery.

  That is, in the present invention, in order to preserve or restore a cultural property having a surface on which a coating film is formed, it is applied to the cultural property in the state of a solution or a dispersion and whitened in a state of being exposed on the surface of the cultural property. A method for removing whitened synthetic resin from a surface of a cultural property, comprising a step of rubbing the synthetic resin from the surface of the cultural property by rubbing the resin with a peeling member that is a resin product or a fiber product.

  Forcible peeling of synthetic resin using tweezers is avoided as an act that may damage precious cultural assets that are unique, and enzymes are used to remove whitened synthetic resin Biochemical approaches have been explored. Although it is difficult to imagine from such conventional knowledge, it is possible to remove the whitened synthetic resin without damaging the cultural property by rubbing with a resin product or a fiber product. The whitening of the transparent synthetic resin is also a process in which the applied synthetic resin is transformed into fine particles and loses its integrity as a continuous film and becomes weak against frictional forces. It is considered that the change in the structure of the synthetic resin accompanying the secular change is one of the reasons that the whitened synthetic resin can be scraped off.

  The method of the present invention is suitable for easily removing the whitened synthetic resin exposed on the surface of the cultural property without damaging the cultural property. In addition, the method of the present invention removes the synthetic resin that is exposed to the surface and impairs the appearance of the cultural property, in other words, while leaving the synthetic resin that has penetrated inside and prevents the peeling of the coating film. This makes it possible to remove the synthetic resin from the useless and harmful part while leaving the synthetic resin at the required part.

It is a photograph of the pillar picture of the building before implementing the process of removing the synthetic resin whitened in Example 1. FIG. It is the photograph of the pillar picture of a building after implementing the process of removing the synthetic resin whitened in Example 1. FIG. It is a microscope image of the waist long push color of the building before implementing the process of removing the synthetic resin whitened in Example 1. FIG. It is the waist image of a long-length push-colored building of the building after implementing the process of removing the whitened synthetic resin in Example 1. It is a figure which shows the position of whitened PVA in the image of FIG. It is a figure which shows the position of whitened PVA in the image of FIG. It is the microscope image of the waist long push-colored color of the building before implementing the process of removing the synthetic resin whitened in Example 2. FIG. It is the microscope image of the waist long push color of the building after implementing the process of removing the synthetic resin whitened in Example 2. FIG. It is a figure which shows the position of whitened PVA in the image of FIG. It is a figure which shows the position of whitened PVA in the image of FIG. It is a photograph of the waist long push coloring of the building after implementing the process of removing the synthetic resin whitened in Example 3. It is the photograph which image | photographed a mode that the process which removes the synthetic resin whitened in Example 3 is implemented.

  Hereinafter, embodiments of the present invention will be described, but the following description is not intended to limit the present invention to specific embodiments.

  In this specification, “cultural assets” refers to tangible cultural assets, specifically buildings, paintings, sculptures, crafts, handwriting, classics, ancient documents, archeological materials, historical materials, and other tangible cultural assets. It is used as a meaning term and it does not matter whether it is designated as a national treasure, an important cultural property, or a registered tangible cultural property. In the present specification, the “coating film” refers to a deposit formed as a decoration, painting, ink brush, etc., regardless of the material, shape, color, and degree of deterioration. Therefore, for example, paintings in which the deterioration of the original image is so difficult that the details of the original image are difficult to distinguish are also included in the “coating film”.

  Typical synthetic resins that have been used to prevent the peeling off of cultural properties are PVA and water-soluble acrylic resins. These resins are suitable for application in a solution or dispersion state. PVA has been dissolved or dispersed in water, and the water-soluble acrylic resin has been supplied after being dissolved or dispersed in water or an organic solvent appropriately selected according to the type thereof. However, the method of the present invention can also be applied to the removal of synthetic resins other than PVA and water-soluble acrylic resins, such as polyester resins, urethane resins, and cellulose resins.

  Some of the coatings on the surface of cultural properties have deteriorated considerably over a period of time exceeding hundreds of years, and in some cases more than a thousand years. Synthetic resin has been recognized as a useful industrial material for preventing and repairing damage to the paint film, but it is exposed at least to the surface of the cultural property as it is exposed to whitening due to aging. The removal is required for the parts that are present. In addition, when applying an organic solvent solution of synthetic resin to the surface of the cultural property, using a highly hydrophilic organic solvent (for example, acetone), and applying the organic solvent solution to the surface of the cultural property in a high humidity environment, Synthetic resin on the surface of cultural properties may be whitened. As described above, the whitened synthetic resin loses its form as a continuous film to become fine particles, and the fine particles are exposed on the surface of the cultural property in a form in which they are in close contact with each other or separated. The diameter of the fine particles is on the order of submillimeters, and is about 0.01 mm as an example. If the fine deposits having such a diameter are removed by rubbing by friction, the burden on the surface to which the deposits are deposited is small.

  In one embodiment of the present invention, the synthetic resin whitened on the surface of the cultural property is scraped off from the surface of the cultural property by rubbing along the surface of the cultural property using a peeling member that is a resin product or a textile product. Remove. This operation can be performed using power equipment, but manual operation is suitable for reliably protecting the surface of the cultural property. It should be noted that prioritizing removal of bleached synthetic resin may result in damage to the surface of cultural properties.

  In a preferred embodiment of the present invention, a peeling member that can be deformed by contact with a whitened synthetic resin is used, and the whitened synthetic resin is removed from the surface of the cultural property while the peeling member is in contact with the whitened synthetic resin and deformed. Scrap. This form is suitable for entwining the whitened synthetic resin while reliably preventing damage to the coating film on the surface of the cultural property.

  Specifically, the above-mentioned preferable form can be implemented by using a resin product softened with an additive such as a resin solid containing a plasticizer. Examples of the plasticizer include various general plasticizers such as various ester compounds such as phthalate esters. The preferred form described above can also be carried out by using a resin product that is easily deformed by the presence of a microporous material, such as a synthetic sponge. Therefore, a preferable example of the peeling member is a resin product containing a plasticizer and / or having a microporous structure.

  The preferable form mentioned above can also be implemented by using a textile product. The fiber product is one of the members that easily deforms by contact with the whitened synthetic resin because there are voids between the fibers constituting the product.

  In a more preferable embodiment of the present invention, the whitened synthetic resin is scraped off from the surface of the cultural property while a part of the peeling member deformed in contact with the whitened synthetic resin is separated from the rest of the peeling member. . This form is suitable for applying a strong frictional force to a whitened synthetic resin without applying excessive stress to the coating film on the surface of the cultural property. Further, in this embodiment, it is possible to prevent the whitened synthetic resin from being taken into the resin product or the like and causing scratches, stains, etc. to the coating film on the surface of the cultural property. This form can be typically implemented by using a plastic eraser or a polishing sponge, which will be described later.

  An example of a resin product that can be used in the method of the present invention is an eraser. Examples of preferable eraser include plastic eraser and rubber eraser. The plastic eraser is produced by adding a plasticizer to a synthetic resin such as polyolefin or polyvinyl chloride. Rubber erasers are made from natural or synthetic rubber and are harder and stronger than plastic erasers. By rubbing with these erasers, the whitened synthetic resin falls off from the surface of the cultural property along with so-called “eraser” that separates and falls off from the eraser.

  An eraser suitable for efficient removal of the whitened synthetic resin is a plastic eraser. The plastic eraser is moderately soft and has an excellent effect of entwining the fine synthetic resin. The rubber eraser is inferior in the removal efficiency of the whitened synthetic resin than the plastic eraser, but is suitable for use at a site where a strong frictional force should be applied.

  Another example of a suitable eraser is a kneaded eraser. An additive such as a plasticizer is blended in the kneaded rubber so as to be soft enough to be kneaded by hand. The kneaded eraser is used to attach the deposits to be removed to the surface, and unlike the plastic eraser or the like, basically “eraser” is not generated. The kneaded eraser is inferior in the removal efficiency of the whitened synthetic resin than the plastic eraser, but is suitable for use at a site where a strong frictional force should not be applied because the coating film is severely deteriorated. In addition, since a plasticizer etc. ooze out from a kneaded rubber and may contaminate cultural assets, it is preferable to select a kneaded rubber which is difficult for an additive such as a plasticizer to ooze out.

  Another example of a resin product that can be used in the method of the present invention is a synthetic sponge. Examples of preferable synthetic sponges include polishing sponges such as melamine sponge and hydrophilic resin sponges such as PVA sponge. These sponges may be used by containing a liquid such as water as necessary. The abrasive sponge, like a plastic eraser, is suitable for efficient removal of the whitened synthetic resin because the whitened synthetic resin is scraped off while being worn.

  Textile products that can be used in the method of the present invention are not particularly limited, and knitted fabrics, woven fabrics, nonwoven fabrics, felts, and papers can be used as appropriate. Preferred textile products are nonwoven fabrics and paper. Moreover, there is no limitation in particular also in the fiber which comprises a fiber product, For example, the product comprised from various fibers, such as an aramid, a cellulose, nylon, vinylon, polyester, polyolefin, rayon, can be used.

  Textile products are often too thin to be used for rubbing the surface of cultural properties, so it is advisable to supplement the thickness in combination with a support material so as to be suitable for the work. For example, in the case of manual work, the fiber product is affixed to the base material and supported so that it can be easily held by hand, or the core material is wrapped in the fiber product or wrapped around the core material. It is convenient to construct a member. The material of the support material such as the base material and the core material is not particularly limited, but may be appropriately selected according to the state of the surface of the cultural property. When there is a possibility that the coating film may be damaged when a large frictional force is applied, it is desirable to use a support material having cushioning properties. A support material having a cushioning property can be obtained, for example, by rolling a thin paper (for example, tissue paper) close to the core material without preparing a material.

  Thus, in a preferred embodiment of the present invention, the peeling member supports the fiber product having a peeling surface for scraping off the whitened synthetic resin, and the back side opposite to the peeling surface of the fiber product. Material.

  In a preferred embodiment of the present invention, the whitening synthetic resin is rubbed with the peeling member while the peeling member and / or the whitened synthetic resin contains water or an organic solvent, preferably water. The organic solvent may be appropriately selected from polar solvents such as alcohol and nonpolar solvents such as toluene according to the surface of the cultural property and the state of the coating film. Usually, lower alcohols, particularly alcohols having 1 to 3 carbon atoms are used. Use is preferred. The presence of a liquid such as water may contribute to efficient removal of the whitened synthetic resin.

  In a preferred embodiment of the present invention, before the step of scraping off the whitened resin, the surface of the cultural property is made of glue, cloth nori, cellulose derivative and (meth) acrylic ester resin in order to prevent peeling of the coating film. A step of applying and drying an adhesive liquid containing at least one selected from the group is further performed. This form is suitable for the preservation and restoration of a cultural property whose surface or the coating film on the surface is fragile. If the coating film is prevented from peeling off using an adhesive in advance, it is easy to peel off the whitened synthetic resin while preventing damage to the surface of the cultural property. Adhesives include traditional adhesives such as glue aqueous solution and cloth laver extract, aqueous solutions or ethanol solutions of cellulose derivatives (methyl cellulose, hydroxypropyl cellulose, etc.), aqueous emulsions or organic solvent solutions of (meth) acrylate resins. May be used. “(Meth) acrylic acid” means acrylic acid or methacrylic acid.

  The above-described anti-peeling using a traditional adhesive is recommended to be applied particularly when peeling such as layer peeling or powder peeling is observed on the surface of the cultural property. Even if peeling is not observed, if there is a possibility that the coating film may be peeled off by the removal operation of the whitened synthetic resin, it is preferable to carry out peeling prevention using the above-mentioned adhesive.

  In the above-described peeling prevention using a traditional adhesive, before drying the adhesive liquid, if necessary, a liquid-absorbing sheet is layered on the area where the adhesive liquid has been applied and pressed with a spatula to repair the peeling. Work may be performed. Preferred liquid absorbent sheets are nonwoven fabric and paper. By this work, it becomes possible to remove the surplus adhesive liquid by absorbing it into the liquid absorbing sheet as well as repairing the peeling. If necessary, before the adhesive liquid is dried, a liquid-absorbing sheet is stacked on the part where the adhesive liquid is applied, and a solvent (for example, water) of the adhesive liquid is further supplied from the liquid-absorbing sheet to remain on the coating film. You may implement the operation | work which adsorb | sucks and collect | recovers with a stain | pollution | contamination etc. which exist in a coating film, diluting adhesive liquid.

  Drying after applying the adhesive is preferably performed by air drying at room temperature. However, when it is necessary to shorten the drying time, the adhesive liquid may be heated to a temperature that does not adversely affect the material such as the coating film and the adhesive.

  Specifically, as the adhesive liquid containing glue and / or cloth nori, glue aqueous solution, cloth nori extract and the like can be used. As the aqueous glue solution, a glue solution (which is not particularly limited, for example, Kyojo glue, three thousand glue, grain glue, deer glue, glue glue) added to water and heated to 60 to 70 ° C. is used. can do. The concentration of glue is preferably 1 to 10% by weight. As the cloth nori extract, one obtained by boiling and filtering cloth nori with water, or one obtained by immersing cloth nori in water at room temperature to extract a viscous component can be used. The concentration of the cloth nori extract is preferably 0.1 to 5% by weight.

  In one embodiment of the present invention, the whitened synthetic resin can be removed without supplying water to the coating film, that is, by a dry process. This form is advantageous in that it can be applied to a coating film that should not be exposed to a liquid, unlike a wet removal technique using an enzyme composition. This form can be carried out simply and efficiently by using an eraser such as a plastic eraser.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited by the following Examples.

<Example 1>
In Example 1, the operation of removing the whitened synthetic resin on the colored coating film drawn on the wall surface of the building was performed (see FIG. 1). The whitened synthetic resin contains at least PVA (the same applies to Examples 2 and 3). This work was carried out after peeling off using an aqueous glue solution in consideration of the state of the mural.

(Preventing film peeling)
First, the foreign matter and dust adhering to the mural were wiped off using a brush and a brush. Next, a brush or syringe was used for the part where the layer peeling was observed in the coating film, and the glue aqueous solution was applied using a brush for the part where the powder peeling was recognized for the coating film. The aqueous glue solution was prepared by adding water and dissolving with heating so that the amount of Kyojo glue was in the range of 1 to 10% by weight. At this time, the concentration of glue was appropriately adjusted according to the site to be applied.

  Next, polyester paper ("Polyester paper No. 8" (manufactured by Yoshida Shoten Co., Ltd.)) is layered on the area where the glue aqueous solution is applied, and the coated film is fixed in that state by pressing with a small spatula from above the polyester paper. The peeling was repaired. Further, this portion was pressed onto the polyester paper with tissue paper to absorb the excess aqueous glue solution, and then the polyester paper and tissue paper were peeled off. Subsequently, new polyester paper (same as above) is layered on the coating film, and purified water is applied to the coating film with a brush through the polyester paper to dilute glue remaining in the coating film and to remove stains present on the coating film. From the surface. Thereafter, the polyester paper was pressed with tissue paper to absorb excess water, remaining glue and dirt, and the polyester paper and tissue paper were peeled off. The applied aqueous glue solution was allowed to dry for about 24 hours at room temperature.

(Removal of whitened synthetic resin)
By rubbing the whitened synthetic resin with a plastic eraser “Radar S-60” (manufactured by SEED), the whitened synthetic resin was removed from a part of the wall surface on which the coating film was formed. The removal work with the eraser was carried out manually.

  FIG. 1 and FIG. 2, FIG. 3 and FIG. 4 showing the state before and after removal (both magnifications are 120 times; one scale is 0.01 mm), and comparing FIG. 5 and FIG. It can be understood that most of the whitened synthetic resin can be removed from the area from the center to the lower left of 2 and that the coating film is not damaged in this area. By removing the whitened synthetic resin, the original lightning pattern can be seen (FIG. 2).

<Example 2>
In Example 2, it was considered that the film had a purple color at the beginning of production, but the coating film in which the original color was difficult to visually recognize due to the whitened synthetic resin (particularly attached near the center of FIG. 7) was used. . In Example 2, instead of the eraser, the same as in Example 1 except that a melamine sponge ("Migaki-san" (manufactured by Japan Ryutsu Sangyo Co., Ltd.) was included in water and lightly squeezed was used. The peeling work and the synthetic resin removal work were carried out, and the removal work with the melamine sponge was carried out manually in Example 2. In Example 2, the coating film after the whitened synthetic resin was removed was dried. Therefore, the tissue paper was pressed through the polyester paper used in Example 1 to absorb moisture.

  FIG. 7 and FIG. 8 showing the state before and after removal (both are 120 times magnification; one scale is 0.01 mm), and FIG. 9 and FIG. 10 can be understood that most of the whitened synthetic resin was removed. . The original color of the coating became visible by the removal operation. In Example 2, as in Example 1, damage to the coating film was not confirmed.

<Example 3>
In Example 3, unlike Examples 1 and 2, the whitened synthetic resin was removed without carrying out the anti-peeling operation. The synthetic resin removal operation was performed in the same manner as in Example 2.

  Referring to FIG. 11 showing the state after removal and FIG. 12 showing the state during removal, it can be confirmed that the whitened synthetic resin was almost removed. Also in Example 3, damage to the coating film was not confirmed.

  Particularly advantageous peeling members from the viewpoint of removal efficiency are the plastic eraser and polishing sponge (melamine sponge) used in the above examples. However, it has been confirmed that the whitened synthetic resin can be removed also by other erasers such as kneaded eraser, other synthetic sponges such as PVA sponge, and textile products such as polyester paper.

  In Examples 1 and 2 described above, the whitened synthetic resin was removed after carrying out the peeling prevention, but the peeling prevention can be omitted depending on the state of the coating film (Example 3). It has also been demonstrated that whitened synthetic resin can be removed from the surface of cultural assets by a dry process using a plastic eraser as a peeling member.

  The present invention has great utility value in the field of preservation and restoration of various cultural properties that should retain their value in the next generation.

Claims (9)

  In order to preserve or restore a cultural property having a surface on which a coating film has been formed, a synthetic resin that is applied to the cultural property in the form of a solution or dispersion and whitened in a state of being exposed on the surface of the cultural property is obtained as a resin product. Or the method of removing the whitened synthetic resin from the surface of a cultural property which comprises the process of scrubbing from the surface of the said cultural property by rubbing using the peeling member which is a textile product.   Using the peeling member that can be deformed by contact with the whitened synthetic resin, the whitened synthetic resin is scraped from the surface of the cultural property while the peeling member is brought into contact with the whitened synthetic resin to be deformed. The method of claim 1.   3. The whitened synthetic resin is scraped off from the surface of the cultural property while a part of the peeling member deformed in contact with the whitened synthetic resin is separated from the remaining part of the peeling member. The method described.   The said member for peeling and / or the said whitened synthetic resin contain the water or the organic solvent, and the said whitened synthetic resin is rubbed using the said member for peeling. Method.   The method according to claim 1, wherein the peeling member is a resin product containing a plasticizer and / or having a microporous structure.   The method according to claim 1, wherein the peeling member is an eraser.   The method according to claim 1, wherein the peeling member is a synthetic sponge.   The peeling member includes a fiber product having a peeling surface for scraping off the whitened synthetic resin, and a support material that supports a back surface of the textile product opposite to the peeling surface. Item 6. The method according to any one of Items 1 to 5.   Before the step of scraping off the whitened resin, at least selected from the group consisting of glue, cloth nori, cellulose derivative and (meth) acrylate resin on the surface of the cultural property in order to prevent peeling of the coating film The method of any one of Claims 1-8 which implements the process of apply | coating and drying the adhesive liquid containing one.