KR20040022795A - Cleaning and Conservation Agent for Stone Cultural Heritage - Google Patents

Abstract

PURPOSE: A detergent for stone cultural assets is provided, to remove the impurities adhered to the stone cultural assets effectively and to treat and prevent the discoloration due to a lichen. CONSTITUTION: The detergent is an aqueous solution comprising a dispersant, an oxidizing agent, a chelating agent and an anti-lichen agent. Preferably the dispersant is a polyethylene glycol-based ionic surfactant; the oxidizing agent is hydrogen peroxide, hydrogen peroxide-urea or benzoyl peroxide; the chelating agent is ethylene diamine tetraacetic acid, hydroxyethylene diamine tetraacetic acid, dihydroxyethylene diamine tetraacetic acid, 1,3-propylene triamine pentaacetic acid, triethylene tetramine hexaacetic acid, nitrilotriacetic acid or hydroxyethyl iminodiacetic acid; and the anti-lichen agent is a tetrakis(hydroxymethyl)phosphonium salt.

Description

Cleaning and Conservation Agent for Stone Cultural Heritage

The present invention relates to a cleaning agent. More specifically, the present invention relates to a cleaning agent used to clean the stone cultural property.

In Korea, from the prehistoric age to the Three Kingdoms period, relics excavated from residences and burial mounds are mainly excavated with stone relics such as stone pagoda, stone pagoda, buildings, and love buds. Of the 1,200 designated cultural assets of the country, 300 or more are accompanied by masonry or stone products, accounting for 25% of all designated cultural properties. As such, the number of stone cultural properties among the national and local designated cultural properties is largely because they were maintained as they were without destruction or arson by the telephone, unlike tributary cultural properties. However, recently, the pollution of the air is intensifying, and the damage of the stone cultural property is seriously underway due to the steady damage caused by environmental microorganisms. Therefore, preservation measures are urgently needed.

Most of Korea's stone cultural assets are granites, and biotite granite is the most occupied, and hornblende granite is next. Representative stone cultural properties of biotite granite include Jeonglimsaji 5-story Pagoda, Gaetae-ji 5-story Pagoda, and Beopcheonsa Temple. The granite stone granite is composed of five-storied pagoda of Muyangsa Temple, five-storied pagoda of Gwannhapsa, three-storied pagoda in Sancheong Beomhak-ri, five-storied pagoda in Jeonam-ri, and three-storied pagoda in Jiseok.

In terms of meteorological aspects, the deterioration factor of stone cultural properties is due to weathering phenomenon, which is a complicated physical change caused by moisture, temperature, and wind speed. This weathering is mainly caused by biological weathering along with physical and chemical weathering. Looking at this in more detail as follows.

1) physical factors

Temperature changes and permeable freezing are the main factors. With respect to the temperature change, the stone has a particularly low thermal conductivity, so the rock, which is influenced by the direct heat of the atmosphere and the intersection of the temperature, is repeatedly destroyed and expanded between the surface and the interior. In addition, when water penetrates into the cracks of the rock and freezes, the volume of the rock expands and the rock tissue is destroyed.

2) chemical factors

The main chemical weathering agents are dissolution, oxidation, reduction and hydrolysis. Oxidation and reduction are a kind of chemical reactions, and chemical reactions with oxygen in the air cause the minerals in the stone to be oxidized, simply to form rust, and to turn into colored iron oxides, making the stone surface dark brown. Hydrolysis causes a chemical reaction by the influence of water penetrated between the minerals constituting the stone, causing the particles to dissolve and eventually causing a risk of destruction. Particularly, outdoor materials are gradually dissolved at high temperatures, so when acid or soil is contained in soil or ground, the material of the stone in contact with it weakens or changes. do.

This results in the release of ammonia acetate and humic acid from sulfuric acid from bacteria, lichens, and algae that grow on the topsoil, and these acids dissolve in groundwater and penetrate the stone cultural rock, eventually decomposing minerals. This is a kind of chemical weathering.

3) biological factors

Most of the stone cultural properties are exposed to the lichen, which is a symbiosis of algae and fungi, and are exposed for a long time, so that the weathering resistance is weak and the weathering zone is formed, resulting in surface peeling phenomenon. Many of the stone cultural properties listed in the indecipherable state is witnessed many cases, this is the damage caused by lichens. The ecological structure of lichens is under the epidermal layer, and under the epidermal layer is the myeloid layer, which contains fungal fungi. There is a short root at the bottom and it attaches to the rock surface. The Gonniacia layer is a layer of single cells of algae with chlorophyll, where carbohydrates are produced by carbonation. Fungi in the myeloid layer multiply by carbohydrates containing algae as nutrients.

At this time, lower plants such as algae actively breed and produce organic acids. This is collectively called Jiuisan, which is the main culprit that causes discoloration of masonry. It is also called colored organic acid. Lichens that grow peculiarly depending on the type of rock, for example, grow limestone (Lecideacea) in limestone and produce yellow Rizoparpic acid (Rhizoparpic acid). Xanthoria parientina grows in granite and retains yellow-red parrientine as its pigment. The fungi, another symbiotic organism of lichens, acquire nutrients from organic matter and actively proliferate, and the lichens gradually multiply and the rock surface is covered with lichen cells. Lichens have higher holding efficiency than rocks, and moreover, it is possible to supply organic materials such as proteins, which are introduced to the cells, and to create an environment in which microorganisms can grow between lichens and the rock surface.

4) Factors caused by air pollution

Recently, due to the development of industry, the air pollution problem has become a serious social problem.

The SO _x, NO _x, CO ₂ emissions to the atmosphere as well as to form an acid rain accelerates the damage of cultural assets sikieo promote the dissolution of the various ions from the stone cultural properties eluted from the rock ^{K +, Na -, Ca -} , Mg 2 ^- and as a reaction to precipitate a white precipitate _{(Na 2 SO 4, K 2} SO 4, CaSO 4, Na 2 CO 3, K 2 CO 3, CaCO 3, MgCO 3) on stone cultural properties surface to significantly damage the cosmetic.

Cleaning operations for the preservation process of stone cultural property generally use a cleaning agent to first clean dust, dirt, oils and organic components, and then to remove peroxides or other residues to completely remove contaminants or other residues stuck deep in the pores. The organic materials are oxidized by oxidizing agents such as chlorine oxide, and the organic or inorganic acid solution is used to corrode part of the rock skin layer to completely remove contaminants from the stone. However, in general, the chloride ion (Cl ^-) in aqueous acid solution is used as it is, which contains an acid containing generate secondary pollutants tan to react with the rock components and sulfate ion (SO4 ^2-) also various cations in the rock It reacts with them to form sulfate, the secondary pollutant, and precipitate on the surface of stone cultural properties. In addition, HCl, H ₂ SO ₄ and the like dissolve almost all the components constituting the rock is not suitable for use as a stone cultural property cleaning agent.

Currently, detergents most often used as cleaning agents of stone cultural properties are anionic surfactants whose main ingredients are sulfonate groups or carboxylate groups, so the pH of the solution must be made alkaline at least 7 to maintain the surfactant activity. However, if the solution is alkaline, there is a fear that secondary precipitates are formed in the stone during washing. Recently, detergent builders such as triphenyl phosphate (TPP), carbonates, silicates, sulfates, etc. have been used in detergents to reinforce the cleaning power of detergents, but they also have the risk of forming precipitates of inorganic salts on stone surfaces. You can not use detergent for the purpose. In particular, phosphate remains in the masonry and causes a secondary pollution such that red tide organisms become more active after a certain period of time after washing. In addition, since soap used in daily life is mainly composed of stearic acid, white colloidal precipitates are formed on the surface of the stone after use unless hot water is used during washing.

As a patent related to stone cultural property cleaning treatment, Korean Patent Application Publication No. 2001-99017 is the only patent applied to date. This technology relates to cleaning agents whose main components are oxidizers / corrosion agents / surfactants, which may be effective in preserving damaged masonry cultural properties, but use toxic and difficult-to-handle materials such as hydrofluoric acid (HF). It is pointed out that it is not prescribed for lichen which is the main cause of the damage.

The present invention provides a stone cultural property cleaning agent exhibiting the effect of extinction and control of lichens acting as a major culprit of damaging the stone cultural property, while easily removing foreign substances stuck to the stone cultural property by the proposed method to overcome the above problems. I would like to.

The cleaning agent of the present invention includes an aqueous solution containing a surfactant, an oxidizing agent, a chelating agent, an antilipid agent, and the like. The surfactant used in the present invention is a polyethylene glycol type surfactant, and preferably has a molecular weight of 500 to 10000. Polyethylene-based surfactants are excellent in washability, have low critical micelle concentration (CMC), can be used at low concentrations, and exhibit neutrality and are environmentally friendly. The molecular weight of the polyethylene glycol type surfactant used in the present invention is suitably 100 to 10000 and most preferably has a molecular weight between 100 and 5000. The addition amount is 0.01% to 10% by weight, most preferably 0.1% to 5% by weight. Anionic surfactants (mainly sulfonate groups or carboxylates), which are widely used for general cleaning purposes, should have an alkaline pH of 7 or more in order to maintain the surfactant activity. If the stone solution is alkaline, there is a possibility that a secondary precipitate is formed in the stone at the time of washing, and therefore an anionic surfactant is not used.

Oxidizers include inorganic oxidizers such as hydrogen peroxide, inorganic / organic oxidizers such as hydrogen peroxide-urea and organic oxidants such as benzoyl peroxide. Of these oxidants, hydrogen peroxide-urea is most preferred. This is because urea acts as a stabilizer for long lasting oxidizing power of hydrogen peroxide. The concentration of the oxidant is from 0.1% to 10% by weight, preferably from 0.5% to 5% by weight. If the concentration is less than 0.1% by weight, the desired cleaning effect cannot be obtained. If the concentration is more than 10% by weight, it is not preferable because the oxidation power is strong and it is likely to corrode to the normal part of the stone cultural property. The active ingredient of the oxidizing agent is hydroxy radical, which decomposes with time, and the oxidizing power is decreased. Therefore, it is most preferable to keep it in the form of two-part form and add it just before cleaning, but the decomposition rate of hydroxy radical is not so fast. Because of maintaining stability for a few days, when used within three days after the preparation of the cleaning agent, it is the same in terms of effect even if the oxidizing agent is added and stored in one-part form before use. The role of the oxidant in the present invention serves to facilitate the desorption by oxidizing the foreign matter and coloring material attached to the stone.

Examples of the chelating agent used in the present invention include ethylenediaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, dihydroxyethylenediaminetetraacetate acid, 1,3-propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, tri Ammonium salts such as ethylene tetraamine hexaacetic acid, nitrilotriacetic acid, hydroxyethyliminodiisacetic acid, metal salts and alkali salts. The role of the chelating agent is to form a complex with the desorbents at the time of washing, thereby preventing the desorbers from re-adhering to the surface of the cultural property to enhance the cleaning effect. These chelating agents can be used individually or in combination of 2 or more suitably. The concentration of the chelating agent is not particularly limited. The concentration is generally from 0.01% to 1% by weight of the total amount of chelating agent. The concentration is preferably 0.05% by weight to 0.1% by weight in view of the cleaning effect and economy. If the concentration is 0.01% by weight or less, no cleaning effect can be obtained. If the concentration is more than 1% by weight, it is not only economically disadvantageous, but also undesirable by lowering the effect of weakening the role of the oxidant.

In the present invention, tetrakis (hydroxymethyl) phosphonium salt was used as an additive for controlling lichens. Tetrakis (hydroxymethyl) phosphonium salt is a substance having antilipophilic properties, and its concentration is 0.01% to 1% by weight, more preferably 0.05% to 0.5% by weight.

The pH of the cleaning agent of the present invention is not particularly limited. Generally, detergents can be used at pH in the range of 3 to 12. Potassium hydroxide (KOH), ammonia or tetramethylammonium hydroxide (TMAH) can be used when the cleaner is used under basic conditions and organic or inorganic acids can be added when the cleaner is used under acidic conditions, but as mentioned above. Preferably use of inorganic acids such as HCl and H ₂ SO ₄ is preferably avoided. In the present invention, except for special cases, it is most preferable to wash at a neutral pH of about 6-8.

The present invention provides a method for cleaning a stone culture material comprising a surfactant, an oxidizing agent, a chelating agent, a dispersant, and an anti-lipid agent. Stone cultural properties washed according to this method are not only able to restore their original appearance by removing foreign substances and coloring matters, but also effective in extinction and control of lichens, the main culprit of the damage of stone cultural festivals. to be.

The invention is described in more detail by the following examples. The following examples are illustrative and do not limit the scope of the invention.

Examples 1-9

<Preparation of detergent>

5 g of polyethylene glycol (molecular weight 1620) as a dispersant, 20 g of hydrogen peroxide-urea as an oxidizing agent, 5 g of ethylenediaminetetraacetic acid (EDTA) ammonium salt as a chelating agent, and 1 g of tetrakis (hydroxymethyl) phosphonium salt as antilipids to 969 g of water After the addition, using a homogenizer (manufactured by Tokusukika, Japan) was stirred at 1000 rpm for 10 minutes to prepare a cleaning agent.

<Washing of stone culture festival>

In this experiment, samples of granite stone fragments contaminated with lichens and weathering were collected from Gapsa stone cultural properties of Gongsa, Gongju, Chungnam. The washing of stone debris was soaked in the detergent for 3 minutes, rinsed with pure water and dried to observe the cleaning effect.

The stone fragments were observed using the same as much as possible to more objectively determine the effect after cleansing. Table 1 shows the evaluation criteria and evaluation results.

o Removal of deposits

Excellent: completely removed

Good: almost completely removed

Normal: part left

Poor: Most deposits remain

o Removal of coloring matter

Excellent: completely removed

Good: almost completely removed

Medium: partially colored

Poor: The original color remains intact

Comparative Example 1

In order to compare the effects of the present invention was evaluated and analyzed by the above method, except that a solvent in which 5g of household powder detergent was added to water. The results are shown in Table 1.

Table 1. Evaluation of cleaning power by detergent composition

EDTA: Ethylenediamine tetraacetate

PDTA: 1,3-Propylenediaminetetraacetate

THP: Tetrakis (hydroxymethyl) phosphonium

PEG: Polyethylene glycol

Examples 10-14

To verify the anti-lipidic effect of the present detergent After the stone fragments were treated in the detergents prepared in the respective compositions, the treated fragments were exposed to the natural environment, and the surface was observed after 5 months.

Table 2 shows the evaluation criteria and evaluation results.

o Clothing effect

Excellent: no lichens on the debris

Good: Part of the debris appears

Normal: Appears less than half of debris

Poor: Appears on more than half of the debris

Comparative Example 2

In order to compare the effects of the present invention was evaluated and analyzed by the above method, except that a solvent in which 5g of household powder detergent was added to water. The results are shown in Table 2.

Table 2. Anti-loaf effect

* The effect (usually) shown in Example 10 is believed to be due to the bactericidal effect of H ₂ O ₂ -Urea

Claims (6)

Detergent, oxidizing agent, chelating agent, anti-lipid solution The stone culture material cleaner according to claim 1, wherein the dispersant is a polyethylene glycol type ionic surfactant. According to claim 1, The oxidizing agent stone culture material cleaning agent characterized in that hydrogen peroxide, hydrogen peroxide-urea, benzoyl peroxide The chelating agent of claim 1, wherein the chelating agent is ethylenediaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, dihydroxyethylenediaminetetraacetate acid, 1,3-propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexa Stone cultural property detergent characterized by ammonium salt, metal salt, alkali salt such as acetic acid, nitrilotriacetic acid, hydroxyethyliminodiisacetic acid The anti-lipidic agent according to claim 1, wherein the stone cultural property cleaner is characterized by a tetrakis (hydroxymethyl) phosphonium salt. The stone cultural material cleaner according to claim 1, wherein the active ingredient comprises polyethylene glycol, hydrogen peroxide-urea, ammonium salt of ethylenediaminetetraacetic acid, and tetrakis (hydroxymethyl) phosphonium salt as main components.