JPH0348230B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a coating composition having excellent antiseptic and antifungal properties and containing zeolite solid particles carrying silver ions having a bactericidal effect. [Prior Art] Environmental pollution caused by mold growing on painted surfaces has been a problem in houses, hospitals, and factories, especially pharmaceutical and food factories. Furthermore, in the case of water-based paints, which have been widely used in recent years because of their high safety and ease of handling, there has been a problem of spoilage due to bacteria or fungi during the manufacturing process and storage. Therefore, various antiseptic and antifungal agents have been added to paints as a method to prevent the growth of bacteria and mold. In other words, after the toxicity of organic metals such as organic mercury agents and their toxicity was pointed out, organic chlorine and
Organic sulfur compounds have been used. However, it cannot be said that its low toxicity, antiseptic, and antifungal properties are necessarily satisfied. In view of the current situation, the present inventors conducted various studies and found that silver ion-supported zeolite solid particles, in which a small amount of silver ions were supported by ion exchange from a low-concentration silver salt solution, do not discolor and have good dispersibility in paints. The present invention was completed based on the discovery that a coating composition containing this compound has low toxicity and exhibits strong antiseptic and antifungal properties. That is, in the present invention, zeolite solid particles having a specific surface area of 150 m ² /g or more and a SiO ₂ /Al ₂ O ₃ molar ratio of 14 or less are impregnated with a silver salt solution having a concentration of 0.1 mol/g or less to obtain a solution of 0.001 to 5 wt. % (based on anhydrous zeolite) of silver ions supported by ion exchange into a paint composition. Zeolite is generally an aluminosilicate with a three-dimensionally developed skeleton structure, and is generally xM _2/o O・Al ₂ O ₃・ySiO ₂・based on Al ₂ O ₃
It is expressed as zH ₂ O. M represents an ion-exchangeable metal ion, usually a monovalent to divalent metal, and n corresponds to this valence. while x and y
are the coefficients of metal oxide and silica, respectively, and z represents the number of crystal water. Many types of zeolites are known, differing in their composition ratio, pore diameter, specific surface area, etc. However, the specific surface area of the zeolite solid particles used in the present invention is 150 m ² /g or more (based on anhydrous zeolite), and the zeolite constituent SiO ₂ /Al ₂ O ₃
The molar ratio should be 14 or less, preferably 11 or less. The solution of water-soluble silver salts having a bactericidal effect used in the present invention easily undergoes ion exchange with the zeolite defined in the present invention, so utilizing this phenomenon, the required amount of silver ions can be transferred to the zeolite. However, the specific surface area of the zeolite particles holding silver ions is
Two conditions must be met: 150 m ² /g or more and a SiO ₂ /Al ₂ O ₃ moly ratio of 14 or less. It has been found that if this is not the case, the object of achieving effective bactericidal action cannot be obtained. This is thought to be because the absolute amount of silver ions fixed on the zeolite is insufficient in a state where the effect can be exerted. In other words, this is thought to be due to the physicochemical properties of the zeolite, such as the amount of exchange groups, exchange rate, and accessibility. Therefore, zeolites with a high SiO ₂ /Al ₂ O ₃ molar ratio, known as molecular sieves, are completely unsuitable for the present invention. In addition, in zeolite with a SiO ₂ /Al ₂ O ₃ molar ratio of 14 or less, it is possible to uniformly retain silver ions, which have a bactericidal effect, and for this reason, it is only by using such zeolite that a sufficient bactericidal effect can be achieved. It turns out that it can be obtained. In addition, the acid resistance and alkali resistance of zeolite with a high silica ratio, where the SiO ₂ /Al ₂ O ₃ molar ratio of zeolite exceeds 14, is higher than that of SiO ₂
However, it also takes a long time to synthesize, and from an economic standpoint, it is not a good idea to use a zeolite with such a high silica ratio. The natural or synthetic zeolite with SiO ₂ /Al ₂ O ₃ ≦14 described above for this coating composition can be used satisfactorily in terms of acid resistance and alkali resistance, and is also economically inexpensive. This is a possible solution. From this meaning as well
The SiO ₂ /Al ₂ O ₃ molar ratio must be 14 or less. As the zeolite material having a SiO ₂ /Al ₂ O ₃ molar ratio of 14 or less used in the present invention, either natural or synthetic zeolite can be used. For example, natural zeolite is analcime (Analcime).
_SiO2 / _Al2O3 =3.6 _{~ 5.6} ), Chabazite: _SiO2 / _Al2O3 =3.2~6.0 and 6.4~
7.6), Clinoptilolite:
SiO ₂ /Al ₂ O ₃ = 8.5 to 10.5), Erionite (Erionite: SiO ₂ / Al ₂ O ₃ = 5.8 to 7.4), Faujasite (Faujasite: SiO ₂ / Al ₂ O ₃ = 4.2 to 4.6),
mordenite: SiO ₂ /Al ₂ O ₃ = 8.34
~10.0), Philipsite:
SiO ₂ /Al ₂ O ₃ =2.6 to 4.4), and the like. These typical natural zeolites are suitable for the present invention. On the other hand, typical synthetic zeolites include A-type zeolite (SiO ₂ /Al ₂ O ₃ = 1.4-2.4),
-type zeolite (SiO ₂ /Al ₂ O ₃ = 2-3), Y-
_These synthetic _zeolites are suitable as _{the zeolite} material of the _present invention _. . Particularly preferred are
Synthetic A-type zeolite, X-type zeolite, Y
- type zeolites and synthetic or natural mordenites. The zeolite is preferably in the form of fine particles, particularly preferably in the form of powder particles with a particle diameter of 5 microns or less, preferably 2 microns or less. In the present invention, silver ions must be retained in the zeolite solid particles by an ion exchange reaction. If it is simply adsorbed or attached without ion exchange, the antibacterial effect and its durability will be insufficient. The various zeolites defined in the present invention are
When converting to Ag-zeolite, a solution of a water-soluble silver salt such as silver nitrate is usually used, but care must be taken not to increase the concentration too much.
For example, when converting A-type or At the same time, silver oxides etc. are precipitated in the zeolite solid phase. This has the disadvantage that the porosity of the zeolite is reduced and the specific surface area is significantly reduced. Furthermore, even if the specific surface area does not decrease significantly, the bactericidal activity decreases due to the presence of silver oxide itself. This was previously unknown. In order to prevent the precipitation of excess silver into the zeolite phase, it is necessary to keep the concentration of the silver solution low, and the safe concentration of AgNO ₃ is
Less than 0.1M. When using an AgNO ₃ solution with such a concentration, the specific surface area of the Ag-zeolite obtained is almost the same as that of the zeolite used as the conversion material.
It was found that the bactericidal effect can be demonstrated under optimal conditions. Further, important conditions for the component to be added to the paint are weather resistance, such as not discoloring over time or under heating, and ease of uniform dispersion in the paint. Zeolite solid particles containing silver ions in an amount of 5% by weight or less by ion exchange with a silver solution with a concentration of 0.1M or less do not yellow or brown over time or under heat, and these fine particles do not aggregate. Therefore, it is easy to uniformly disperse it into the paint. However, when the concentration of the silver solution is higher, the resulting silver ion-supported zeolite solid particles tend to discolor and agglomerate. Note that in addition to silver ions, copper ions and zinc ions can also be contained by ion exchange. In the case of ion exchange with copper ions, if the concentration of copper salt is too high, the same phenomenon as described above with Ag-zeolite occurs. For ^{example ,} when performing an ion exchange reaction with A-type _or
The disadvantage is that the porosity of zeolite decreases due to the precipitation of basic precipitates such as Cu ₃ (SO ₄ )(OH) ₄ and the specific surface area decreases significantly. In order to prevent the precipitation of excess copper into the zeolite phase, the concentration of the aqueous copper solution used should be diluted, for example 0.05M.
It is preferable to keep it below. Such a concentration of _CuSO4
It was found that the specific surface area of the Cu-zeolite obtained when the solution is used is almost the same as that of the zeolite used as the conversion material, and that it has the advantage of being able to exhibit its bactericidal effect in an optimal state. In ion exchange with zinc, such a phenomenon is not observed when the salt used is around 2 to 3M. When carrying out the above-mentioned ion exchange reaction by the batch method, the zeolite material may be immersed in a salt solution having the above-mentioned concentration. In order to increase the metal content in the zeolite material, the number of batch treatments can be increased. On the other hand, when treating a zeolite material by a column method using a salt solution having the above concentration, the desired metal-zeolite can be easily obtained by filling an adsorption tower with the zeolite material and passing the salt solution through it. can get. The amount of metal in the above metal-zeolite (based on anhydrous zeolite) is 0.001 for silver.
~5% by weight. When silver, copper and zinc ions are used in combination, the total amount of metal ions may be 35% by weight or less based on the metal-zeolite (based on anhydrous zeolite), although the preferred range depends on the composition ratio of the metal ions. , approximately 0.001-15% by weight. Furthermore, even if metal ions other than silver, copper, and zinc, such as sodium, potassium, calcium, or other metal ions, coexist, the bactericidal effect is not hindered, so there is no problem with their remaining or coexistence with these ions. In the present invention, there are no restrictions on the coating film forming elements, coating auxiliary elements, etc., but representative examples include acrylic resin-based and vinyl acetate-based emulsion paints, acrylic resin-based and alkyd resin-based solvents. Examples include mold paint. In the present invention, in order to produce a coating composition containing solid zeolite particles holding silver ions having a bactericidal effect, coating auxiliary elements are added to the coating film forming element and stirred to uniformly disperse the coating composition. Good. In the present invention, the amount of zeolite solid particles added (B weight % relative to the coating composition) and the amount of bactericidal silver (A weight % relative to the metallic zeolite) are both related to the bactericidal effect. In order to demonstrate sufficient antiseptic and mold resistance, A
It is desirable to adjust the value of B (%) to be 0.025 or more. The bonding strength between the zeolite defined in the present invention and silver ions is extremely large, and the coating composition containing such metal zeolite has strong antiseptic and antifungal properties and lasts for a long time. Furthermore, the zeolite-based particles holding silver ions having a bactericidal effect of the present invention are aluminosilicate containing silver, sodium, potassium, etc., and their low toxicity is a special characteristic advantage of the present invention. be. It was confirmed that the coating composition thus obtained had excellent antiseptic and antifungal properties during the manufacturing process, during storage, and after painting. Next, examples of the present invention will be described, but the present invention is not limited to these examples. In addition, % in the present Examples and Comparative Examples is by weight unless otherwise specified. Reference Example 1 Table 1 shows unconverted natural and synthetic zeolite particles used in the examples of the present invention. Each zeolite was obtained by crushing and classifying crude raw materials to obtain the desired particle size. In Table 1, the A-type zeolite is abbreviated as _Z1 , the X-type zeolite as _Z2 , the Y-type zeolite as _Z3 , and the natural mordenite as _Z4 . The particle diameter, water content, and specific surface area of these zeolites were as shown in Table 1. Next, 250 g of dried fine powder of each type of zeolite listed in Table 1 was collected, and a 1/10M silver nitrate aqueous solution was added to each.
500 ml was added and the resulting mixture was kept under stirring at room temperature for 3 hours to perform ion exchange. After the silver-zeolite obtained by this ion exchange method was filtered, it was washed with water to remove excess silver ions.
Next, the water-washed silver-zeolite was dried at 100 to 105°C and then ground to obtain a fine powder of silver-zeolite. The silver content and specific surface area of the obtained dried silver-zeolite product were as shown in Table 2.

【table】

[Table] Among the silver-zeolite conversion products, silver-A type zeolite is abbreviated as _Z5 , silver-X type zeolite as _Z6 , silver-Y type zeolite as _Z7 , and silver-natural mordenite as _Z8 . Example 1 and Comparative Example 1 70% emulsion containing 43% acrylic resin, 10% titanium dioxide, 4% hydroxyl ethyl cellulose 10%, 25% Demol EP 8% (manufactured by Kao Soap Co., Ltd.)
Acrylic resin emulsion paint consisting of 2% water
100 g was weighed out in a tin can, and various zeolites shown in Table 2 at predetermined concentrations were added thereto and mixed by stirring. Type A zeolite (Z ₁ ) shown in Table 1
Comparative Examples 1-1 and 1-2 are those to which zeolite was added and those to which zeolite was not added. Next, the number of paint rot-causing bacteria is approximately 1×10 ⁶ /ml.
Bacillus subtilis, Pseudomonas diluted to
1 ml of a mixed suspension of aeruginosa and Escherichia coli was inoculated onto the paint. Seal the can and store at 28℃ x 7
After culturing for one day, the bactericidal effect was evaluated based on the number of viable bacteria in the paint. The results are shown in Table 3.

[Table] The coating composition of the present invention had a strong bactericidal effect and exhibited excellent antiseptic properties during the manufacturing process and storage. Incidentally, the coating properties of the coating composition to which the zeolite was added and the composition to which it was not added were compared, but almost no difference was observed. Example 2 and Comparative Example 2 Various zeolites shown in Table 2 at predetermined concentrations were added to the acrylic resin emulsion paint shown in Example 1 and mixed with stirring. A sample to which type A zeolite (Z ₁ ) shown in Table 1 was added was referred to as Comparative Example 2-1, and a sample to which no zeolite was added was referred to as Comparative Example 2-2. A test piece was prepared by applying the above coating composition twice to a wooden board with a diameter of 30 mm and 2 mm so as to form a uniform coating, and drying at room temperature for 48 hours. The test piece was immersed in water for 18 hours, taken out, and left at room temperature for 2 hours.
Dry at ~85°C for 2 hours. (All of the above drying was carried out by hanging the test piece.) Next, the test piece was attached to the center of the culture surface of a plate medium consisting of 1 portion of water, 40 g of glucose, 10 g of peptone, and 10 g of agar. Furthermore Aspergillus
niger, Penicillium funiculosum,
Cladosporium cladosprioides，Aureobasidium
1 ml of a mixed spore suspension of Pullulans and Gliocladium virens was evenly spread over the surface of the medium and the test piece, and the Petri dish was covered with a lid and cultured at 28°C for 14 days. The results are shown in Table 4. In addition, the case where bacteria did not grow is shown as ++, the case where bacteria grew on about 1/3 or less of the test piece is shown as +, and the case where bacteria grew on about 1/3 or more of the test piece is shown as -. The coating composition of the present invention was shown to have a strong bactericidal effect and excellent antifungal properties.

【table】

Claims (1)

[Claims] 1 Specific surface area of 150 m ² /g or more and 14 or less
Zeolite solid particles with a molar ratio of SiO ₂ /Al ₂ O ₃ are impregnated with a silver salt solution with a concentration of 0.1 mol/or less.
A method for producing a preservative and anti-mold coating composition, which comprises mixing in a coating material zeolite solid particles on which 0.001 to 5% by weight (based on anhydrous zeolite) of silver ions are supported by ion exchange. 2 Zeolite solid particles are A-type zeolite,
2. A method for producing a coating composition according to claim 1, which comprises Y-type zeolite, Y-type zeolite, or mordenite.