JPS60137971A - Coating composition for verdigris treatment - Google Patents

Abstract

PURPOSE:To provide titled composition capable of artificially forming verdigris by its coating on copper products, comprising verdigris fine powder having specific size consisting mainly of basic copper sulfate and/or basic copper carbonate, resin emulsion and verdigris-forming reagent. CONSTITUTION:The objective composition made up of (A) 5-40wt% of verdigris powder containing <=50wt% of fine powder with -325 mesh, pref. >=40wt% of fine powder with -100--200 mesh, consisting mainly of basic copper sulfate and/or basic copper carbonate, (B) 5-20wt% on a solid resin basis, of a resin emulsion with its stabilized pH region falling on acidic side, (C) 1-15wt% of a chlorine ion-free reagent capable of forming verdigris by the reaction with copper (pref. containing ammonium ion, sulfate ion or divalent copper ion), and (D) the rest of water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a coating composition for artificial patina treatment which is sprayed on copper products such as copper strips and copper plates used for roofing sheets to be patina treated. In more detail, by spraying or coating copper products, a coating with good adhesion and good appearance can be obtained from the beginning, and a patina will gradually develop under the coating. The present invention relates to a coating composition for patina treatment formulated in such a way that the patina formed on the base is replaced by the paint film after many years of application.

Once a patina is formed on the surface of copper, corrosion of the copper is substantially inhibited and the copper has a calm aesthetic appearance with a unique pale blue color, which is why it is highly desirable. However, in order to produce natural patina, it is necessary to go through a period of generation of cupric oxide for black color (it takes a long time of 5 to 6 years for natural patina to occur).

For this reason, in order to avoid artificially forming a patina, a method is used to avoid reaction with copper by spraying or applying a chemical solution after the roof has been cut down or just before the roof is squared on site. However, this method using a chemical solution is labor-intensive and time-consuming because it is mainly carried out on-site, and the resulting patina film has poor adhesion and can easily fall off when rubbed with your fingers or be washed away by wind and rain. There were drawbacks.

The present invention has been made to solve these drawbacks, and aims to provide a paint composition for patina treatment that does not require on-site application, is inexpensive, and has good adhesion, weather resistance, and appearance. do.

This object of the invention is achieved by a coating composition having the following formulation.

That is, the present invention uses a verdigris powder containing basic copper sulfate and/or basic copper carbonate as a main component and containing -325 mesh fine powder at 5 to 40@m%, which has a discharge stability range on the acidic side. A certain emulsion resin is used as a resin component c5~2
A coating composition for patina treatment comprising 1 to 15% by weight of a chlorine ion-free agent that produces patina by a chemical reaction and the balance water.

The patina powder used in the coating composition of the present invention contains basic copper sulfate and/or basic copper carbonate as a main component, and -3
It contains 50% or less of fine powder of 25% mesh, and initially plays the role of a pigment, but after a long period of time, it blends harmoniously with the patina that naturally occurs from the base, and also has a patina. The higher the powder content, the faster the formation of patina from the base. In other words, under normal circumstances, naturally occurring patina components are mainly composed of basic copper sulfate and are usually mixed with metal salts such as iron.
In clean countryside areas, basic copper carbonate is the main component. The patina powder of the present invention is similar to this natural patina, as well as the artificially produced basic line II! The main component is copper and/or basic carbonate steel powder. In particular, it is most appropriate to use basic copper sulfate as the main ingredient, which resembles the actual patina and is highly economical. Alternatively, it may contain intermediate products. Furthermore, in order to resemble the color tone of natural products, an iron salt in the form of ferrous sulfate or the like may be added in an amount of 1% by weight or less. It is not preferred to replace this patina powder with other commercially available patina pigments. The patina powder used in the present invention is a basic salt of copper, and when it is attached to a copper product, it becomes darker depending on the environment, for example, in rainy weather.
Another advantage is that in coastal areas, the linear tint becomes stronger, and over a longer period of time, the light bluish part of the natural verdigris hue gradually expands. Add the basic salt produced by the neutralization method to the verdigris powder in water! It is not appropriate to produce a coating composition by substituting a cloudy substance or by substituting a sol-like substance obtained by concentrating and filtering this, and mixing these with other resins or chemicals (it is not appropriate to manufacture a coating composition. Similarly, the patina of the present invention The powder is -325
It is necessary that the fine powder of the mesh is 50% by weight or less. The content of sol and fine powder is 50% by weight or less because the content of sol and -325 mesh fine powder exceeds 50% by weight. This is because the appearance of the coating film is uniform and flat compared to the case where coarse grains are used, making it look like a coat of paint, which is undesirable. Moreover,
There is also the problem that the natural patina under the coating is inhibited because the supply of moisture between the copper and the coating is less than when using relatively coarse grains. Furthermore, when the paint film deteriorates, if it is a flat continuous paint film, it will peel off as flakes with a certain area, but if you use coarse particles and avoid continuous paint films, it will not only be difficult to peel off, but will also peel off in powder form. There are subtle advantages.

In particular, such problems are more likely to occur when the patina powder contains more than 50% by weight of 1325 mesh powder. From this, it is desirable that the particle size of the patina powder is -100 to -200 mesh at 40% or more. Further, the weight content of the patina powder in the coating composition is 5 to 40% by weight, preferably 10 to 25% by weight. If the amount of the patina powder added is less than 5% by weight, the pigment component is insufficient in terms of hue, which is undesirable, and the effect of promoting the formation of the base patina is poor as well as the agent.

On the other hand, if it exceeds 40% by weight, the viscosity of the paint at °C becomes too high, making it difficult to apply.

The emulsion resin contained in the coating composition of the present invention should be mixed with the patina powder and the agent that produces patina, since both have a weakly acidic pH in the range of 3 to 6.
, the pl-1 stability ranges need to be comparable. Vinyl acetate resin emulsions and the like meet this requirement, and C may also be used, which may contain commonly used plasticizers, stabilizers, protective coids, etc. added to these emulsions. Furthermore, a wetting agent or the like may be added to the coating components of the coating composition of the present invention. The appropriate content of emulsion resin in the coating composition is 5 to 20% by weight as a resin component. For example, when converted to 1 emulsion of 60% by weight of II degree, 8 to 33% by weight is added as an emulsion to the coating composition. That is appropriate.

If the resin content is less than 5% by weight, the adhesion of the coating will be insufficient, and the
When the amount exceeds % by weight, the rate of development of patina under the coating film becomes slow.

Conventional agents that cover the formation of 'TJB' by a chemical reaction with copper include a mixed aqueous solution of CI (NO3)2, N and aCJ, a mixed aqueous solution of CIIcJ2 and Nt-1aCJ, and H
CJ, CLI (CI-+3 Coo)2, NH4C
J, Cu (NO3)2, CII COK, Na
A mixed aqueous solution of CJ, a mixed aqueous solution of NH2Cl and Cu (NO3)2, a mixed aqueous solution of N84CJ and (NH4)7 CO3, and a mixture of these with As or a flu compound are known. However, according to the findings of Present Invention 8, etc., the combination of agents for producing patina through a chemical reaction with copper is not a combination that always includes chlorine ions, as in the above-mentioned composition, which has not been frequently used in the past. It is desirable that the material does not contain chlorine ions. In the case of paint films made from paint compositions containing Zunawara chlorine ions, the chlorine ions tend to fade the greenish-blue color caused by verdigris powder to a white color, and when the temperature of the copper surface exceeds 50°C, the color under the paint film deteriorates. A black oxide film may develop on the copper surface, resulting in an unfavorable appearance. Therefore, as an example of a agent that generates patina suitable for use in the coating composition of the present invention, it contains ammonium ions, bM III ions, and divalent copper ions as essential components, and further contains effective agents such as nitrate ions and acetate ions. Combinations that can further include one or more components are included. The appropriate content of these drugs in the coating composition is 1 to 15% by weight, depending on the content of various drugs. In other words, if it is less than 1%, the chemical reaction between the copper and the coating film will not occur sufficiently.
The adhesion to the substrate is poor, and even after a long period of time, there is little patina on the substrate.As a result, the patina of 11 adhesion is not seen after the paint film deteriorates and peels off, and zinc oxide or copper oxide Copper forms in the peeled area, making it look unattractive. Moreover, even if it is added in an amount exceeding 15% by weight, not only the patina generation effect becomes saturated, but also the miscibility of the coating composition deteriorates, resulting in a decrease in adhesion.

The coating composition of the present invention, which is composed of the combination of patina powder, resin, drug, and water as described above, is manufactured by mixing in a commonly used method. The water content is adjusted so that the viscosity of this coating composition is 0.2 to 0.7 poise when used for construction by spraying as described below. If the viscosity is less than 0.2 Boaz, the sprayed droplet particles will be large, and when these particles hit the material to be treated, they will spread out in a plane, which will take advantage of the spraying method described below! do not have. Moreover, if the viscosity exceeds 0.7 Boaz, the viscosity is too high and construction is difficult.

In order to apply the coating composition of the present invention to copper products such as strips and strips for roofing boards, a coating film is formed by spraying on the degreased copper surface, coating with a brush, etc., and then dried at room temperature or in a drying oven. You can force dry it. When a paint film is formed, the appearance is maintained by the pigment action of the patina powder, and the interaction between the copper and the components in the paint composition that starts after painting improves the copper and the paint film. The adhesion of the paint gradually improves, and a patina gradually forms and spreads under the paint film. However, in order to take advantage of the characteristics of the coating composition of the present invention, spraying is more suitable than brushing or roll coater for coating other than repair coating. The reason for this is the same as the reason why fine particles of verdigris powder are not preferred and verdigris sol is unsuitable as a coating composition.

In other words, coatings created by brush coating or roll coating methods not only have a flat appearance similar to that of painted paint, which is unappealing, but also create a continuous coating, which limits the penetration of moisture into the copper substrate. (green) The production rate of 4H is relatively slow, and when the coating film deteriorates, it does not peel off in powder form but as flakes with a certain area, which is unfavorable in terms of appearance. On the other hand, when the repainting composition of the present invention is sprayed, the droplets adhere to the copper in the form of enclosing one to several pieces of patina powder, and do not form a continuous coating film, but microscopic ones. It adheres in an uneven state and causes defects such as the above-mentioned brush application! do not have. There are air spray cans, airless cans, mortar cans, etc. used for this purpose.
From another perspective, there are hand gun types and automatic gun types. In order to manufacture the entrance edge bronze plate at a low cost in a factory, it is desirable to use a drying oven such as a flat type automatic coating machine comprising an automatic gun, a conveyor, a can moving mechanism, etc. It is also preferable to use a small number of guns to eliminate unevenness.The main parts of this can, such as the paint nozzle and needle valve, are made of a prepared alloy. Prevents precipitation on metal parts and is preferable for maintenance.

Furthermore, before applying the coating composition of the present invention to copper, it is also possible to heat-treat or generate a thin curved copper oxide film with a chemical solution containing an oxidizing agent, and then apply the coating to this to improve the adhesion of the coating. Improve I! It is also effective in the sense of suppressing the underlying copper from showing through the paint film and giving a metallic luster in the initial appearance.

Hereinafter, the present invention will be specifically explained based on Examples and Comparative Examples. Incidentally, the numbers of deceased vessels in Table 1 are parts by weight.

Examples 1 to 3 and Comparative Examples 1 to 3 A paint composition for artificial patina treatment was produced by mixing each component in the composition ratio (city axis %) shown in Table 1, and this was applied to a copper test piece. A patina coating film was obtained by Mli coating using the coating method shown in Table 1. Note that the patina powder is obtained by mixing CuS04 aqueous solution with NaO
Some unavoidable intermediate products such as CLISOJ・3CU(ON)2 obtained by neutralization with H 3CuO・SO3・2]1
A precipitate containing 20 was dried and ground. Regarding Comparative Example 2, a precipitate sol before drying and precipitation was used. Also,
The amount of powder is a value C calculated backward from the water content of the sol.

The obtained painted test pieces were exposed to the sun for 3 months at the Iwai coast in Yokohama Prefecture, and were placed in a constant temperature bath kept at 50°C and 95% humidity.
I put it in for 6 hours, and then let it air in the seedlings for 8 hours. Ikuru Doshi C! ) A dry/wet cycle test repeated 0 times and a weather resistance test placed in a weather meter for 1000 hours were conducted. After the dry-wet cycle test, the test pieces were examined for appearance, cross-strength test, and the degree of patina formed on the base after the paint film was peeled off. The results obtained are shown in Table 2. In addition, in the appearance of Table 2, "C" and "fading" indicate that the greenish-blue color is turning white, and "base blackening" indicates that the copper base of the f':j coating has turned black.

In addition, "flat" means that there are no irregularities, and the surface has an appearance that looks like it has been painted. In Table 2, "Good cross cut" means that there is no abnormality even if the dezo is applied to the side of the back or 1" cut and removed. Furthermore, the evaluation of the degree of occurrence of base patina in Table 2 is as follows: Approximately 30% of the area has patina. However, cases where the incidence rate was less than 30% were marked as △.

As shown in Table 2, patina powder, emulsion ingredients,
The coating composition of the present invention, which is prepared by specifying a mulberry agent and adding water to it, can easily produce an artificial patina coating by spraying copper products such as copper roots (=i 4p). It will be done.

Moreover, the resulting film has a stable appearance and good Y-stickiness, and furthermore, patina develops under the film within a relatively short period of time, causing deterioration of the film over time and the resin gradually peeling off and falling off. It has excellent performance in that it replaces the natural patina that forms on the base.

Patent applicant: Mitsui Metal Mining Co., Ltd. Patent applicant: Sankin Tokushu Nuri Co., Ltd. Agent Patent Attorney Ajt Ito Agent: Ben 111, Lee J1 Tetsuya Higashi

Claims (1)

[Claims] 1. Green powder Song 5 to 40 years old containing basic copper sulfate A3 and/or basic copper carbonate as a main component and containing not more than 50% by weight of -325 mesh fine powder , Emulsion resin with a stable range of 118 on the acidic side is used as a resin component of 5 to 20 parts ■
%, a chlorine ion-free agent that produces patina through a chemical reaction such as copper, 1 to 15% by weight, and the balance water. 2. The coating composition according to claim 1, wherein the drug contains ammonium ions, sulfate ions, and divalent copper ions. 3. The patina powder contains 1% by weight or less of iron salt, except for optionally added basic copper carbonate and unavoidable impurities. basic 1al
1. The coating composition according to claim 1, wherein the coating composition is copper. Coating film 311I described in item 3
]A product.