JPH0559308A - Antibacterial coating composition - Google Patents

Abstract

PURPOSE:To provide an antibacterial coating composition having excellent dispersibility of antibacterial agent, exhibiting permanent antibacterial, mildew- proofing and algicidal effects and giving a paint resistant to discoloration with time. CONSTITUTION:A paint is compounded with a phosphoric acid salt compound having an average particle diameter of <=1mum and expressed by formula [M<1> is one or more kinds of metal ions selected from silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium and chromium; A is alkali metal ion, alkaline-earth metal ion, ammonium ion or hydrogen ion; M<2> is tetravalent metal; 0<=6; a and b are positive numbers; c:2 and d:3 when l a+mb=1, and c:1 and d:2 when la+mb=2 (l is valence of M<1>; m is valence of A)].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial coating composition containing a specific phosphate compound having antibacterial properties, and is applicable to various structures such as ships, hospitals and warehouses, bathtubs, toilets and kitchens. It is useful as a paint for coating the surface of various structures and materials such as housing equipment or articles made of various materials such as wood, plastic, concrete and metal.

[0002]

2. Description of the Related Art Conventionally, there has been a problem of environmental pollution due to generation of mold and algae on the surface of paint applied for exteriors of houses, hospitals and factories. In addition, since water-based paints have high safety and are easy to handle, they have been widely used in recent years. However, water-based paints produce spoilage due to bacteria or mold during production or storage. There's a problem. Therefore, as a method for preventing the growth of bacteria and fungi on the surface of the applied paint or in the paint before application, organic metals such as preservatives and fungicides, organic chlorine-based and organic sulfur-based organic compounds are known. Attempts have been made to add system bactericides to paints. However, paints containing these organic fungicides are not always sufficiently satisfactory in terms of safety and durability of antibacterial and antifungal effects.

In recent years, antiseptic and antifungal paints containing a zeolite retaining metal ions having an antibacterial action have been developed (for example, JP-A-60-202162). This coating resin composition is certainly superior to those containing an organic fungicide in terms of safety and durability of antibacterial effect,
There is a problem that the paint discolors remarkably due to metal ions such as silver and copper during storage of the paint or after application. Also,
Since the average particle size of such zeolite is several μm and the maximum particle size exceeds 10 μm, it is difficult to uniformly disperse and mix it in the paint, and the particles settle and agglomerate after long-term storage, and then the zeolite is dispersed and mixed again. There is a problem that even if you try, you cannot do it easily. Furthermore, in some special applications, the thickness of the coating film may be required to be 1 μm or less, and in this case, there is a problem that a flat coating film surface cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a coating material containing a particulate antibacterial agent having antibacterial properties, which is chemically and physically stable, and can be prepared at the time of preparation, storage and after coating. An antibacterial coating composition that does not cause discoloration, etc., and has excellent dispersibility of an antibacterial agent not only during paint preparation but also after long-term storage, and that has a permanent antibacterial, antifungal and antialgal effect. It is what

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that silver, copper, zinc,
Specific phosphate system having metal ions showing antibacterial properties of tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium and chromium ions (hereinafter referred to as antibacterial metal ions) The present inventors have found that an antibacterial coating composition containing a compound retains antibacterial metal ions extremely stably and exhibits antifungal and antibacterial properties for a long time, and has completed the present invention. That is, the present invention relates to an antibacterial coating composition comprising a compound represented by the following general formula [1] and a coating. M ¹ _{a Ab} M ² _c (PO ₄ ) _d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, or hydrogen ions. Is the ion of M ²
Is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6,
Both a and b are positive numbers, and c and d are la + mb
= 1, c = 2, d = 3, la + mb = 2, c =
1 and d = 2. However, l is the valence of M ¹ and m is the valence of A. )

The present invention will be described in detail below. The coating composition of the present invention comprises a phosphate compound and a coating component. O Phosphate Compound The compound used in the present invention is a compound represented by the following general formula [1]. M ¹ _{a Ab} M ² _c (PO ₄ ) _d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, or hydrogen ions. Is the ion of M ²
Is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6,
Both a and b are positive numbers, and c and d are la + mb
= 1, c = 2, d = 3, la + mb = 2, c =
1 and d = 2. However, l is the valence of M ¹ and m is the valence of A. )

The compound represented by the above general formula [1] is
When a + mb = 1, each coefficient of c = 2 and d = 3,
Amorphous or a crystalline compound belonging to the space group R3c, which represents a compound in which each constituent ion forms a three-dimensional network structure, has a coefficient of c = 1 and d = 2 when la + mb = 2, amorphous or Represents a compound in which each constituent ion forms a layered structure. As the phosphate compound used in the present invention, since it is less discolored when exposed to sunlight,
A crystalline compound having a three-dimensional network structure having coefficients of + mb = 1 and c = 2 and d = 3 is preferable.

M ¹ in the above general formula [1] is known as a metal exhibiting antifungal, antibacterial and antialgal properties. Among these, silver is not only safe but also antifungal. ,
It is particularly effective as a metal that can remarkably enhance antibacterial and antialgal properties.

A in the above general formula [1] is at least one ion selected from an alkali metal ion, an alkaline earth metal ion, an ammonium ion and a hydrogen ion, and preferred specific examples are lithium, sodium and potassium. There is an alkali metal ion such as, an alkaline earth metal ion such as magnesium or calcium, an ammonium ion or a hydrogen ion, and among these, lithium, sodium, an ammonium ion and hydrogen are preferred from the viewpoint of the stability of the compound and low cost. Ions are the preferred ions.

M ² in the above general formula [1] is a tetravalent metal, and preferable specific examples thereof include zirconium, titanium or tin. Considering the safety of the compound, zirconium is a particularly preferable tetravalent metal. is there.

The following are specific examples of the phosphate compound represented by the general formula [1]. Ag _0.005 Li _0.995 Zr ₂ (PO ₄ ) ₃ Ag _0.01 (NH ₄ ) _0.99 Zr ₂ (PO ₄ ) ₃ Ag _0.05 Na _0.95 Zr ₂ (PO ₄ ) ₃ Ag _0.2 K _0.8 Ti ₂ (PO ₄ ) ₃ Ag _0.1 H _0.9 Zr ₂ (PO ₄ ) ₃ and some of the Ag in each of the above formulas are replaced with Zn, Mn, Ni, Pb, Hg while maintaining the same charge amount as that of silver ions per mol of the compound. Compound substituted with Sn or Cu, Ag _0.001 Li _1.999 Zr (PO ₄ ) ₂ Ag _0.01 Na _1.99 Zr (PO ₄ ) ₂ Ag _0.01 K _1.99 Sn (PO ₄ ) ₂ 1.2H ₂ O Ag _0.1 (NH ₄ ) _1.9 Ti (PO ₄ ) ₂ .4H ₂ O Ag _0.02 H _1.98 Zr (PO ₄ ) ₂ .1.7H ₂ O and the amount of silver ion per 1 mol of the compound, while maintaining the same charge amount as described above. Part or all of Ag in each formula is Zn, Mn, or Ni. Pb, Hg, Sn, or compounds substituted with Cu.

The average particle size of the phosphate compound used in the present invention is preferably 1 μm or less in order to disperse it uniformly in the paint and prevent sedimentation or aggregation even after storage.

The phosphate compound used in the present invention is synthesized.
Known methods such as firing method, wet method and hydrothermal method
Either method can be used, but it is economical and has a high degree of purity.
To synthesize fine particles of zirconium phosphate with good properties, water
The thermal method is most suitable. As a specific synthesis method, hydrothermal method is used.
An example of the method will be described below. Aqueous solution of zirconium sulfate
Slowly add ammonium dihydrogen phosphate with stirring.
, A precipitate is formed. After that, with a caustic soda solution
Adjust the pH value of the reaction solution to 2 and keep it at 130 ℃
After heating the precipitate in a vessel under saturated vapor pressure for 32 hours,
The precipitate is filtered, washed with water, dried and crushed to obtain crystalline zirconium phosphate.
Konium NH 4 Zr 2 (PO Four) Get three. Furthermore, this result
Amorphous zirconium phosphate in silver nitrate aqueous solution of appropriate concentration
In addition, by stirring, the average particle size is 1 μm or less
Antibacterial phosphate Ag_X(NH Four) 1_-XZr 2 (PO Four) Get 3
It

The value of a in the general formula [1] is the concentration of the antibacterial metal ion in the aqueous solution for supporting the antibacterial metal ion on the phosphate compound, and the phosphate compound in the aqueous solution. By adjusting the dipping time or temperature, it can be appropriately adjusted according to the required characteristics and use conditions.

The value of a in the general formula [1] can exhibit antifungal and antibacterial properties even when it is extremely small, but if it is less than 0.001, it can exhibit antifungal and antibacterial properties for a long time. Considering the possibility of difficulty and the economical efficiency, a value of 0.01 or more and 0.5 or less is preferable.

The preferred blending ratio of the phosphate compound in the coating material differs depending on the components forming the coating material, the purpose of use of the coating material, the use environment, and the object to be coated. In order to impart a general antibacterial effect to the coating film without significantly deteriorating the characteristics of the coating material, it is preferable to add 0.1 to 10% by weight (hereinafter simply abbreviated as%) of the coating solid content. In order to obtain the antifungal property, the blending ratio of 0.01 to 1% is preferable, and the resin component in the coating composition of the present invention is used as a binder of the phosphate compound to apply phosphoric acid to the object to be coated. When a salt compound is to be attached to exert antibacterial properties, it is preferably 10 to 60% with respect to the coating solid content. However, if it is desired to obtain long-term antibacterial effect, rapid attack, or stronger effect, the compounding ratio can be appropriately increased.

The phosphate compound used in the present invention is stable to exposure to heat and light, and its structure and composition do not change at all even after heating at 500 ° C. or higher, and in some cases 800 ° C. In addition, it does not cause any discoloration even when irradiated with ultraviolet rays. Moreover, it does not come into contact with water in a liquid state or change in the skeleton structure even in an acidic solution. Therefore, the antibacterial coating composition of the present invention is not subject to restrictions such as heating temperature or light shielding, unlike the conventional antibacterial coating compositions during the manufacturing process, storage, and use.

Paint component The paint component comprises a coating film forming element, a so-called resin component, and a coating film forming auxiliary element such as a solvent or a diluent, and the coating film forming element is
It consists of main components of the coating film, such as natural vegetable oils, natural resins and synthetic resins, which are the main constituents of the coating film, sub-components such as plasticizers, curing agents, emulsifiers and dispersants, and pigments.

The coating film main element in the present invention is not particularly limited, and may be any of natural vegetable oil, natural resin, semi-synthetic resin and synthetic resin, and may be either thermoplastic resin or thermosetting resin. May be. Specific fats and oils include, for example, linseed oil, sesame oil, dry oil or semi-dry oil such as soybean oil, rosin, nitrocellulose, ethyl cellulose, cellulose acetate butyrate, benzyl cellulose,
Novolac or resol type phenol resin, alkyd resin, aminoalkyd resin, acrylic resin, vinyl chloride, silicone resin, homopolymer type thermoplastic, copolymer type thermoplastic, modified thermoplastic or thermosetting fluororesin, epoxy resin , Urethane resin, saturated polyester resin, melamine resin and polyvinylidene chloride resin. However, since the antibacterial effect is more likely to be exhibited when the coating film is hydrophilic, a hydrophilic one is preferable as the coating film main element.

The form of the paint of the present invention is not particularly limited,
It may be a solution type, a dispersion type or a powder type, and the solvent is not particularly limited, and may be any of a lipophilic organic solvent, a hydrophilic organic solvent and water. Further, the coating composition of the present invention may be of a type that cures by any mechanism, specifically, an oxidative polymerization type,
There are moisture curing type, heat curing type, catalyst curing type, polyol curing type and the like.

○ Preparation Method of Paint The antibacterial paint composition of the present invention is prepared by a conventional method using the above-mentioned phosphate antibacterial agent and paint components by using a general mixing device such as a ball mill, a roll mill, a disper or a mixer. It suffices to sufficiently disperse and mix. In addition, the coating composition of the present invention, since the phosphate-based compound carrying the antibacterial metal ion has excellent chemical and physical stability, the antibacterial metal ion and its skeleton even in an acidic solution. There is no elution of zirconium ions and phosphate ions, which are the forming components,
In addition, it does not have hygroscopicity, and thus the coating material can be manufactured very easily without being subjected to various restrictions. In addition, the antibacterial paint exhibits extremely little deterioration during the compounding of the paint and the subsequent storage or use of the antibacterial paint, and exhibits antifungal, antibacterial and antialgal properties for a long time even in a severe environment.

Coating and Curing Method The coating method of the present invention is not particularly limited, and may be applied according to a known method depending on the coating film forming element, the form of the coating material and the like. Further, the method for curing the coating material of the present invention is not particularly limited, and may be any method such as room temperature drying, heating, irradiation with light rays such as ultraviolet rays, visible light or electron beams, etc., which are known depending on the curing mechanism of the coating material. A curing means can be appropriately adopted according to the method.

The paint contains various pigments and a dispersant which is a sub-component of the coating film, in addition to the main component of the coating film which is the main component. When a conventional antibacterial paint contains a pigment that has a relatively strong reactivity with antibacterial metal ions, the antibacterial metal ions react with the pigment, so the antibacterial effect of the paint cannot be fully exerted. In many cases, the paint discolors. However, since the phosphate compound in the present invention carries an antibacterial metal ion extremely stably, there are almost no problems such as reduction of antibacterial effect and discoloration.

The coating composition of the present invention can be used in various fields requiring antifungal, antialgal and antibacterial properties,
The object to be applied is not limited. Examples of specific applications include ship bottom paint, paint for interior and exterior of hospitals, schools, general houses, food factories, warehouses, etc., painting of walls, ceilings, floors of bathrooms, toilets or kitchens, painting of wood products and plastic products. , Paints for the inner surface of water tanks, water tanks and tubes. In particular,
When the coating material of the present invention is applied to the bottom of a ship, shellfish such as a Fuji pot,
Since it is possible to prevent seaweed or algae from adhering to the bottom of the ship, and the phosphate compound is extremely stable,
Antibacterial metal ions do not elute into seawater even if they come into contact with seawater, and seawater is not polluted.

The present invention will be described in detail below with reference to examples.

【Example】

Reference Example [Preparation of Antibacterial Agent] An aqueous solution of zirconium sulfate and an aqueous solution of ammonium dihydrogen phosphate are mixed so that the ratio of zirconium to phosphorus is 2: 3 to form a precipitate, and an aqueous solution of sodium hydroxide is added. After the pH was adjusted to 2 by using it, crystalline zirconium phosphate was obtained by heating under hydrothermal condition at 150 ° C. for 24 hours. The phosphate compound obtained above was added to an aqueous solution of silver nitrate, stirred at room temperature for 4 hours, thoroughly washed with water, dried and pulverized to obtain an antibacterial agent. The obtained antibacterial agent is a white powder having an average particle size of 0.47 μm. In order to make a comparison with the above antibacterial agent, an antibacterial agent prepared by subjecting commercially available zeolite to silver ion exchange was also prepared. The antibacterial agents obtained above are shown in Table 1.

[0026]

[Table 1]

Example 1 [Preparation of antibacterial coating] The antibacterial agent obtained in Reference Example was added to a urethane emulsion coating.
0.5 parts per 100 parts by weight (hereinafter simply abbreviated as "parts") and 30 parts per 100 parts of solid content in an epoxy resin-based paint diluted with toluene and acetone to adjust the solid content to 10%.
An antibacterial paint was obtained by adding a part thereof. In addition, as a comparison, one without addition of an antibacterial agent was also prepared. Table 2 shows a sample of the antibacterial paint obtained above.

[0028]

[Table 2]

Example 2 [Test for antibacterial activity] Sample No. 1 obtained in Example 1 Paint composition of 1, 2 and 3
The product was subjected to an antibacterial activity test as follows. each
Add 10 g of sterile water to 10 g of the seed coating composition to dilute it.
1 ml of E. coli solution (10 viable cells) 6 pieces / 1ml)
E. After storage at 37 ° C for 1 day and 5 days,
The viable cell count was measured by the pour plate culture method (37 ° C, 2 days).
Decided The measurement results are shown in Table 3.

[0030]

[Table 3]

Example 3 [Antibacterial activity test] Sample No. 1 obtained in Example 1 4, 5 and 6 coating compositions
The product was subjected to an antibacterial activity test as follows. 5c
Paint each coating composition on an mx5 cm aluminum plate and apply the coating
The formed one was used as a sample. Staphylococcus aureus as the test bacteria
Using bacteria, the number of bacteria per aluminum plate is 10 4-10 With 5
To inoculate the surface of the cells uniformly so that
Medium for measuring the number of bacteria (SCDLP liquid medium) after storage for a while
Wash out the surviving bacteria on the test piece with, and use this washing solution as the test solution.
did. About test solution Pour plate culture with culture medium for bacteria count
Test by measuring the viable cell count by the nutrition method (37 ° C, 2 days)
It was converted into the viable cell count per product. The measurement results are shown in Table 4.
You

[0032]

[Table 4]

Example 4 [Weather resistance test] Sample No. 1 obtained in Example 1 A sample was prepared by uniformly coating the coating compositions 1, 2, and 3 on white Kent paper. The weather resistance was measured using a forced deterioration tester UC-1 manufactured by Toyo Seiki Seisakusho Co., Ltd. The exposure condition of UC-1 was to repeat ultraviolet irradiation (60 ° C.) and humidification (40 ° C.) alternately every hour, and the exposure time was 4 hours. Colors (L, a, b) before and after exposure were measured using a color difference meter SZ-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd., and a color difference ΔE was obtained. The measurement results are shown in Table 5.

[0034]

[Table 5]

Example 4 [Redispersibility test] Sample No. 1 obtained in Example 1 About 200 g of the coating composition of 1 and 2 was placed in a beaker and left at room temperature for 24 hours,
As a result of trying to redisperse with a plastic stirring rod,
Sample No. In the coating composition of No. 1, almost no antibacterial agent was settled, and it could be easily redispersed. In the coating composition of No. 2, the antibacterial agent could not be redispersed because the antibacterial agent was precipitated and strongly aggregated.

[0036]

EFFECT OF THE INVENTION Since the phosphate compound in the antibacterial coating material of the present invention is extremely stable chemically and physically,
The antibacterial coating material of the present invention, during production, storage and use, antibacterial metal ions carried on the phosphate compound are not eluted, or spoilage is not generated in the coating composition, and Almost no discoloration or deterioration of antibacterial property. Even after coating, there is almost no discoloration or deterioration of antibacterial properties of the coating film with time. The phosphate compound in the coating composition of the present invention,
Since it can be easily obtained in the form of fine particles having a uniform particle size and an average particle size of 1 μm or less, not only the dispersibility during the production of the coating material but also the redispersibility after long-term storage is good, and therefore, it can be used for a long time. It can exhibit antibacterial, antifungal and antialgal effects permanently. Furthermore, by using a coating composition containing a particulate phosphate compound having an average particle size of 1 μm or less, it is possible to control the film thickness of the coating film of 1 μm or less, and to obtain a smooth coating film surface. Can be easily obtained.

Claims (1)

[Claims] 1. An antibacterial coating composition containing a compound represented by the following general formula [1]. M ¹ _{a Ab} M ² _c (PO ₄ ) _d · nH ₂ O [1] (M ¹ is silver, copper, zinc, tin, mercury, lead, iron, cobalt,
At least one metal ion selected from nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, ammonium ions, or hydrogen ions. Is the ion of M ²
Is a tetravalent metal, n is a number satisfying 0 ≦ n ≦ 6,
Both a and b are positive numbers, and c and d are la + mb
= 1, c = 2, d = 3, la + mb = 2, c =
1 and d = 2. However, l is the valence of M ¹ and m is the valence of A. )