JPH04134009A - Antimicrobial aluminosilicate, production thereof and resin composition using the same - Google Patents

Abstract

PURPOSE:To produce a crystalline or anhydrous amorphous aluminosilicate of a nonzeolitic structure having improved discoloration resistance by burning specific antimicrobial zeolite, destroying the crystal structure thereof and then pulverizing the resultant zeolite into fine powder. CONSTITUTION:A compound, expressed by formula II and having an average particle diameter of 0.1-10mum and a particle size distribution in which a particle part having a particle diameter of (1/2)-(3/2) of the average particle diameter accounts for at least 50% with >=95.5% whiteness is produced by burning synthetic zeolite powder expressed by formula I [0.8<=(x+y+z)<=1.2; 0<x<=0.2; 0<=y<=1; z<=0.7; 1.8<=m<=10; 0<n<=5; M' is bivalent metal of group IIA, IB or IIB; M'' is alkali metal] at >=700 deg.C for >=1hr (preferably at 750-1200 deg.C for 1-5hr), converting the zeolite into amorphous structure or other crystal structures and pulverizing the aforementioned burned substance. A synthetic resin blended with the resultant compound exhibits remarkable discoloration resistance even when exposed to natural light or fluorescent lamps.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an inorganic antibacterial agent based on crystalline or non-grade anhydrous aluminosilicate with a non-zeolite structure, a method for producing the same, and a resin composition containing the antibacterial agent. relating to things.

[Prior Art] Antibacterial zeolite, which is made by adsorbing and supporting antibacterial metal ions on zeolite as a carrier through ion exchange, has been well known, and in particular, zeolite carrying silver ions has been known to have excellent antibacterial properties. Since then, its development has been gaining momentum recently.

For example, JP-A No. 60-181002 discloses that antibacterial properties obtained by replacing some or many of the ion-exchangeable ions in natural or synthetic zeolite with metal ions such as silver, iron, zinc, etc. Zeolite has been disclosed, and is also disclosed in Japanese Patent Application Laid-Open Nos. 63-26580 and 1999. −
Publication No. 257124 proposes an antibacterial zeolite obtained by replacing ion-exchangeable ions in zeolite with ammonium and antibacterial metal ions, or alkaline earth metals and the like with antibacterial metal ions.

Also known are silicate-based inorganic antibacterial agents in which antibacterial metal ions are supported on amorphous hydrous aluminosilicate, which is a precursor of zeolite, or natural layered silicate.

[Problem H to be solved by the invention] However, especially antibacterial zeolite carrying silver ions, it often tends to be colored pale yellow or grayish brown by itself, and it is difficult to add it to synthetic resins, rubber, etc. When blended, the effect of processing temperature is added to give undesirable coloring, which has the drawback of significantly reducing its commercial value.

Recently, this type of antibacterial zeolite has been rapidly developed as a representative inorganic antibacterial agent due to its long-lasting and excellent antibacterial action. It has been relatively improved. Fortunately, coloring after processing has been avoided to some extent by efforts to select resin compounds containing this resin.

However, when silicate-based antibacterial agents are blended with synthetic resins, not only in such antibacterial zeolite 1, they have the disadvantage of gradually becoming colored over time, and this problem has not yet been improved. Such a coloring phenomenon tends to be significantly accelerated by exposure to light. In particular, when a molded product made of a resin composition containing antibacterial zeolite is exposed to fluorescent light, its color changes rapidly and its commercial value is significantly impaired.

This browning and color development of silver zeolite is thought to be due to the chemical action of silver ions, as well as the fact that resin I\ is compounded under heat and deterioration of the resin is accelerated during molding. There is.

In order to suppress such a coloring phenomenon, it is known to support, for example, ammonium ions as described above or ammine (11-isomer ions).

Another method proposed is to use a UV inhibitor in combination.

However, despite many development efforts to date, no technical development has been made to the extent that antibacterial zeolites carrying silver ions can be commercially provided as stable products with suppressed coloration.

An object of the present invention is to provide an inorganic antibacterial agent that solves these problems.

[Means for Solving the Problems] In view of the above facts, the present inventors have conducted numerous studies to solve this problem, and have found that the discoloration of antibacterial zeolite itself and its change over time are caused by antibacterial metal ions. In particular, based on the knowledge that the interaction between supported silver ions and other metal ions, the Na2O component remaining in zeolite, and the ion exchange properties of these cations are dominant, we developed an inorganic antibacterial agent with colorfastness. They succeeded in developing this and completed the present invention.

That is, the inorganic antibacterial agent provided by the present invention relates to a non-zeolite aluminosilicate having resistance to discoloration, and is characterized by the following general formula % [where x, y, z are respectively 0.8≦X+y+z
≦1.2.0×≦0.2.0≦y≦1, z≦0.7−
+n is the number of moles in the range of 18≦M≦10, M′ is a divalent metal belonging to Groups IIA, IB, and IIB of the periodic table, and M″ is an alkali metal. or regarding non-quality anhydrous aluminosilicate.

The present invention will be explained in detail below.

As mentioned above, the inorganic antibacterial agent according to the present invention is a crystalline or non-grade anhydrous aluminosilicate-based white powder, but one characteristic of crystalline aluminosilicate is that it does not have a zeolite crystal structure. There is.

That is, the inorganic antibacterial agent according to the present invention is made from antibacterial zeolite having a specific composition as described below, which is heated and calcined until the zeolite crystal structure is substantially destroyed. Therefore, it becomes amorphous or converts to another crystal structure.

Crystalline minerals vary depending on the chemical composition of the antibacterial zeolite used as the raw material, but examples include nepheline (Na20
・＾12034Si02), anno-sai l□(CaO・
^12031sio2), Carnegiite (Na20・
^LO+ '2SiO2) or Garnite (Zn
04LO3) etc. are recognized by X-ray diffraction.

In addition, in the above, the zeolite crystal structure is substantially destroyed, which refers to the property that zeolite crystals have substantially no ion exchange effect.
This means that there is no problem even if some of the strongest diffraction lines of the zeolite crystal are observed in terms of X-ray diffraction.

Furthermore, as can be seen from the above, one of the characteristics of such aluminosilicate is that, unlike zeolite, it is substantially anhydrous. Therefore, unlike zeolite anhydride, this anhydride does not re-adsorb and condense. However, by substantial it is meant that under normal storage conditions, a moisture content of the level of equilibrium moisture is acceptable.

Next, in the present invention, amorphous aluminosilicate refers to aluminosilicate whose crystal structure is destroyed by firing a specific antibacterial zeolite, and the bonds of the aluminosilicate become amorphous during the reorganization process. In particular, it is characterized by being in an amorphous state while having substantially the particle characteristics such as particle shape and size of zeolite.

Although the inorganic antibacterial agent according to the present invention has a specific composition as described above, it is based on the composition of the raw material zeolite described below, and is not determined from the viewpoints of antibacterial properties, discoloration resistance, practicality, etc. be.

Furthermore, it is desirable that such an inorganic antibacterial agent be in the form of a fine powder as much as possible in order to enhance its antibacterial action and further enhance its practical value.

Therefore, the average particle size (D50) is 0.1~10μ
It is preferably in the range of 0.5 to 5 μm0, and D5o
Particularly preferred are those having a sharp particle size distribution in which particles having a particle size of 1/2 to 3/2 of the total particle size account for at least 50%, preferably 60% of the total.

The inorganic antibacterial agent according to the present invention has an antibacterial effect with a broad antibacterial spectrum that is equal to or more than the antibacterial effect of antibacterial zeolite, but unlike antibacterial zeolite, it has significantly improved resistance to discoloration. The whiteness is 95
Stable above %.

In particular, this resistance to discoloration is remarkable when it is blended into a synthetic resin, and it has remarkable discoloration resistance even when exposed to natural light as well as fluorescent light.

Next, the present invention provides an industrially advantageous method for producing such an inorganic antibacterial agent, which is characterized by the general formula: % formula % nHz [where x, y, z are each 0.8≦x
+y 1 Z≦1.2, O< x≦0.2.0≦y≦1, z
≦0.7, m and n are each 1.8≦餉≦10.0<
The number of moles with a range of n≦5, M' is group nA of the periodic table, I
Calcination of a synthetic zeolite powder represented by a divalent metal belonging to Group B or Group IIB, where M'' represents an alkali metal, to destroy the zeolite crystal structure of the powder and convert it into an amorphous or other crystal structure. and a pulverizing step of treating the baked product obtained from the previous step with an air pulverizer.

In the present invention, the antibacterial zeolite l- used as a raw material is a synthetic sodium zeolite supported with antibacterial cations such as silver, copper, and dumbbell through cation exchange, and has the above molar ratio composition. It's what you have.

Such zeolites themselves are more resistant to discoloration than conventional antibacterial zeolites, and are also preferred from a practical standpoint.

In the above general formula, the value of m is 1 as a zeolite.
．． Various synthetic zeolites ranging from 8 to 10 are applicable.

Practically, for example, type A zeolite, type X zeolite,
Examples include Y-type zeolite, P-type zeolite, and mordenite, but A-type zeolite is particularly preferred from an economic standpoint. In the present invention, the antibacterial zeolite used as a raw material also includes amorphous hydrated aluminosilicate, which is its precursor, because it has an ion exchange effect and can support antibacterial metal ions. shall be held.

The particle size preferably has the same distribution as described above.

In antibacterial zeolite, silver is an essential metal ion due to its antibacterial ability, and in the general formula above, it is in the range of 0 x ≦ 0.2, but it is For example, silver ions require an ion exchange rate of 1 to 10% with respect to the original soot and lithium ions. 1%
If it is less than 10%, the antibacterial activity will be insufficient, while if it exceeds 10%, the antibacterial activity will be saturated and the tendency for discoloration will be strong.

The metals other than silver ions supported by ion exchange include one or more divalent metals belonging to Group IIA, Group IB, or Group nB of the periodic table, and the ion exchange rate of these metals is It is preferable that the content is 20% or more based on 1 to 10% of lithium.

In terms of antibacterial activity, when antibacterial metal ions such as gold, copper, zinc, or mercury are used together with silver ions, the antibacterial spectrum is expanded and the product is effective against a wider variety of bacteria and fungi.

On the other hand, from the viewpoint of resistance to discoloration, it is preferable to support metal ions such as magnesium, calcium, copper, or zinc in the divalent metal. Furthermore, from the viewpoint of discoloration resistance of antibacterial zeolite, it is important that the content of sodium and chlorine ions is particularly low, and the sodium content is
The content of a2O is 10% by weight or less, especially 8% by weight or less, and the chlorine ion content is 500ppm (l) or less, especially 25% by weight or less.
01] p Tn or less, which is as unsuitable as possible, is desirable.

In the mutual relationship between sodium, chlorine, and silver ions, the general formula 11/X is 20 or less, and the weight ratio CI! /A
It is desirable for 9 to be 0◯1 or less for resistance to discoloration.

If the amount of Na2O in the antibacterial zeolite exceeds 10% by weight, the deterioration of the molded resin will be accelerated during kneading or thermoforming of the molded resin composition containing it, and there will be a tendency for initial coloring.

As can be seen from the following, the antibacterial zeolite used as a raw material in the present invention is a synthetic sodium zeolite treated with ion exchange to carry predetermined amounts of antibacterial ions, divalent metal ions, etc. in addition to silver ions. It is particularly important from the viewpoint of both antibacterial properties and discoloration resistance that the composition satisfies the predetermined composition expressed by the above general formula.

Note that ion exchange treatment is well known, and antibacterial zeolite can be produced by conventional means.

In the production according to the present invention, it is important to first heat-treat the antibacterial zeolite and perform a calcination step to destroy the zeolite crystal structure and convert it into an amorphous or other crystalline structure. That is, through this step, the calcination operation is sufficient to substantially destroy the raw zeolite crystals and make them amorphous, or convert them into aluminosilicate-1 having another crystal structure, such as nepheline, as described above. It's about adding.

Although the firing conditions vary depending on the composition of the raw material zeolite and the intended use of the product, the firing conditions are at least 700°C or higher for 1 hour or more, preferably at 750°C to 1200°C for 1 to 5 hours.
Bake for an hour.

At temperatures below 700°C, the destruction of zeolite is insufficient, so if it is left in the air, it will return to its original state of zeolite with water of crystallization, and the discoloration caused by the structure of zeolites 1 to 1 will not be sufficiently improved. On the other hand, if the temperature exceeds 1200° C., sintering is significant and powder with good dispersibility cannot be obtained. Also, the firing time may be relatively short if the temperature is high, but
This is the time required for the transformation of the crystal structure, which is often one hour or more. Although it varies depending on the type of zeolite, the calcined product becomes amorphous in the range of 700 to 850°C, and becomes amorphous at 850°C.
In the above case, a non-zeolite crystal plate is included.

Next, it is important to perform a pulverization process in which the obtained fired product is pulverized into a fine powder having an average particle size of 10 μI11 or less.

Since the raw material of the fired product is made up of zeolite particles grown or sintered together, pulverization is essential.

One of the features of the present invention is that this fired product is pulverized into fine powder with an average particle size of 10 μW or less. The reason for this is that if the average particle size exceeds 10 μm, the antibacterial effect will be insufficient and it will be difficult to use. This is because it is not desirable. Grinding can be done using a desired grinder,
Although not particularly limited, an air pulverizer such as a jet mill is preferred in the present invention.

The air pulverizer is a pulverizer that requires pressurized gas, usually a high-speed airflow of pressurized air, in other words, a jet stream, and the type of the pulverizer is not particularly limited as long as it has this mechanism.

- Generally, when pulverizing with this type of machine, the heat generated during adiabatic compression is cooled and converted into a jet stream, but in the present invention, it is rather preferable to pulverize with heated air. Although it depends on the material of the pulverizer, pulverization is carried out at a temperature of approximately 50 to 500°C, preferably 150 to 350°C.

The practical range of compressed air is 5 to 10 kf/cm2/gauge pressure.

Thus, according to the pulverization according to the present invention, particles in which particles are strongly bonded can be effectively pulverized by firing. It goes without saying that in this step, if necessary, a classification operation can be added to adjust the particles to have predetermined particle size characteristics.

Furthermore, the present invention relates to a resin composition in which the above-mentioned inorganic antibacterial agent is blended with various synthetic resins, and the feature is that 0
．． It is characterized by containing 01 to 70 parts.

The applicable resin is not particularly limited, and may include thermoplastic or thermosetting resins as well as elastic resins such as synthetic rubber.

Typical thermoplastic resins include polyvinyl chloride, polyvinylidene chloride, chlorinated resins such as chlorinated polyolefins, polyolefin resins such as polyethylene and polypropylene, polystyrene, polyvinyl acetate,
(Meta) Acrylic I! l resins, other vinyl resins such as polyacetal resins, polyester resins, polyurethane resins, fluororesins, polyamide resins, polyimide resins, polycarbonate resins, olemer resins, silicone resins or AAS resins, ABS resins, AS resins, ABS resins, EVA Examples include copolymer resins such as resins, and they may also be one or more composite resins such as polymer alloys.

Examples of thermosetting resins include phenolic resins, epoxy resins, unsaturated polyester resins, polyurethane resins,
Examples include melamine resin, urea resin, diallyl phthalate resin, silicone resin, etc., and they may be used alone or in combination of two or more.

Examples of synthetic rubber include SBR, BRlIRlNBR,
Examples include elastic resins such as urethane rubber and silicone rubber.

The present invention provides that the inorganic antibacterial agent blended into such synthetic resin is
The amount varies depending on its physical properties, especially the amount of silver supported, and the use of the synthetic resin composition, but in most cases it is in the range of 0.01 to 70 parts by weight per 100 parts by weight of the resin. In the final composition, 0.01 to 20 parts by weight, preferably 0.1 to 20 parts by weight
The amount is 10 parts by weight, but up to 70 parts by weight can be blended in a resin composition configured as a masterbatch. This is because if the amount of the inorganic antibacterial agent is less than 0.01 parts by weight, the antibacterial effect of the resin composition will not be substantially obtained, and the upper limit is often limited for economic reasons and is not considered a practical range. Set.

1F It may be surprising that the resin composition according to the present invention can be applied even to chlorine-based general-purpose resins such as vinyl chloride because of the remarkable discoloration resistance of the inorganic antibacterial agent as seen above.

In addition, in preparing the resin composition, various resin additives can be used in combination.

For example, extender pigments such as titanium oxide, calcium carbonate, and silica, organic or inorganic colorants, plasticizers, crosslinking agents, flame retardants, antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, and resins such as lubricants. The additives can be used in combination with the inorganic antibacterial agent according to the present invention individually or in a one-buck type prepared in advance, if necessary.

The resin composition according to the present invention has a wide range of uses because of its excellent antibacterial action, which does not substantially cause the browning phenomenon caused by changes over time under exposure to light, which conventional silver-supported inorganic antibacterial agents have.

For example, food packaging films, various medical and sanitary appliances,
It is possible to expand the variety of characteristic uses such as devices or their parts, various containers, filters, fibers, synthetic paper, synthetic bones, adhesives, etc.

[Example] In order to explain the present invention more specifically, Examples are shown below.

(Examples 1 to 10 and Comparative Examples 1 to 4) Each measured value in the examples was determined by the following method.

(1) Average particle size Measured using a Coulter Counter (manufactured by Coulter Electronics) with an aperture tube of 30 μM.

(2) Composition analysis It was quantified by atomic absorption spectrophotometry and ICP method.

(3) Loss on ignition (moisture content) Test 1'il 1 g was weighed in a porcelain crucible and heated to 800°C.
It was determined from the weight loss after heating for 1 hour.

(4) Whiteness Whiteness was determined using a standard sample of magnesium oxide using a blue filter using Whiteness Index 1 (manufactured by Kerato Co., Ltd.).

(1) Preparation of inorganic antibacterial agent Sodium type A zeolite, type

Table 1 NaA NaX NaP Gel average particle diameter R50 (utn) 2.8 4.
1 0.9 3.0 (agglomeration) Chemical composition Na2
O16,914,613,'6 21.3 (wt%)
Aβ20327.9 24.0 22.4 31.
4SiO232,535,444,237,1Si
O2/A (! 20 :l molar ratio 1,98
2,50 3.35 2.01 Burning loss (wt%)
22.7 25,9 19.8 10.2 A g N as a soluble salt to provide each ion for ion-exchanging these hydrous aluminosilicates
Os, Zn(NOs)2, and Ca(NO3)2 were used.

Each sample was prepared by the following procedure. Add 1 kg of the raw hydrated aluminosilicate powder shown in Table 1 to 5 liters of distilled water!
It was dispersed and suspended in. While stirring the suspension, an aqueous solution 5e in which a predetermined amount of salts had been dissolved was added, and the mixture was stirred at room temperature for 3 hours to perform ion exchange.

After separating, washing and drying the solid phase by a conventional method, it was calcined at a predetermined temperature for 2 hours. Next, after coarsely pulverizing each of the obtained baked products, 7 kg/am2 gauge pressure (temperature 288°C
) was air milled at a constant flow rate without cooling.

Table 2 shows the preparation conditions for the raw zeolite and the composition and properties of each inorganic antibacterial agent sample obtained.

(2> (Antibacterial test) The antibacterial properties of each sample were evaluated by the following method.

A! 720] A sample containing 501 ng of silver was prepared in advance using bacterially contaminated water (Note 1) or mold diluted water (Note 2).
501ne of ) and slowly stirred in a magnetic cooler for ]0 minutes. Next, this liquid was cultured using a simple microorganism measuring instrument, EasyCult TTC (for aerobic bacteria, fungi, and yeast tests, manufactured by Sanjo Sekiyu Co., Ltd.) and EasyCult M (for fungi and yeast tests, manufactured by Sanjo Sekiyu Co., Ltd.). Test 3) was conducted.

The results are shown in Table 3.

<Note 1> River water diluted with sterile water to a total bacterial count of 10'' - For total bacterial testing (Note 2) 1 g of black mold-infested wall soil diluted to 100+ nN with sterile water - For fungal testing (Note 3) ) Cultivation was carried out in an incubator at 27-30°C for 2 days for total bacteria and 4 days for fungi.

Table (Note 4) The total number of strokes was evaluated based on the relationship between the degree of colony occurrence and the number of bacteria roughly determined in advance. 0 is the case where no colony development is observed.

(Note 5) The degree of fungal contamination was evaluated in the following four stages.

No contamination 10; Light contamination 4-1- Moderate contamination + -1-+: Severe contamination (Note 6) When antibacterial aluminosilicate was not added.

Examples 11 to 20 and Comparative Examples 5 to 8 30 as Ag2O for various synthetic resins shown in Table 4
Add each sample to a concentration of 01B]m, mix and injection mold each], 80 mmX 5011
A test piece of 11+1×1 run was obtained. The color changes of these test pieces immediately after molding and after being exposed to fluorescent light for 30 days were measured using a white standard plate using a digital colorimetric color difference calculator (AUD-C1]-1) manufactured by Suga Test Instruments. Evaluation was made by determining the color difference ΔE).

Table 4 Injection molding temperature (°C) Synthetic resin low density polyethylene (ROOKONICAR G5-360) Polypropylene (Tonen Petrochemical J-209>Nylon (Ube Industries 1013B) Polyvinyl chloride (Nippon Zeon Zeon 103EP) Results in Table 5 As is clear from the figure, when the color difference between the blank and the comparative example is considered, it can be seen that the resin composition according to the present invention has extremely excellent discoloration resistance.

[Effect of the invention] The inorganic antibacterial agent according to the present invention contains a crystalline or non-grade anhydrous aluminosilicate with a non-zeolite structure as an active ingredient, and has an antibacterial effect equal to or higher than that of antibacterial zeolite. ing.

In particular, it is an inorganic antibacterial agent that is resistant to discoloration and has significantly improved discoloration due to exposure to light, which is a disadvantage of antibacterial zeolites.

Further, according to the production method according to the present invention, the highly reliable inorganic antibacterial agent can be industrially advantageously produced using antibacterial zeolite of a specific composition as a raw material.

Such inorganic antibacterial agents have remarkable resistance to discoloration and can be used stably even when mixed with various synthetic resins, so they can add antibacterial function to various molded products based on synthetic resins. can be expected to have many uses.

Claims (1)

[Claims] 1. General formula: [(Ag_2O)_x(M'O)_y(M″_2O)_
z] Al_2O_3・mSiO_2 [where x, y, z
are respectively 0.8≦x+y+z≦1.2, 0<x≦0.
2, 0≦y≦1, z≦0.7, m is 1.8≦m≦10,
M′ represents a divalent metal belonging to Group IIA, Group IB, or Group IIB of the periodic table; M'' represents an alkali metal] It is characterized by being a crystalline or amorphous anhydrous aluminosilicate with a non-zeolite structure. 2. An inorganic antibacterial agent having an average particle size (D_5_0) in the range of 0.1 to 10 μm, and having a particle size distribution in which 1/2 to 3/2 of D_5_0 accounts for at least 50% of the total particle size. The inorganic antibacterial agent according to claim 1, which is an anhydrous aluminosilicate with a whiteness of 95.5% or more. 3. General formula: [(Ag_2O)_x(M'O)_y(M"_2O)_
z] Al_2O_3・mSiO_2・nH_2O [where x, y, and z are each 0.8≦x+y+z≦1.2,
0<x≦0.2, 0≦y≦1, z≦0.7, m and n are the number of moles with a range of 1.8≦m≦10, 0<n≦5, respectively, M' is the periodic law A divalent metal belonging to Group IIA, Group IB, or Group IIB in Table 1, M'' represents an alkali metal] is converted into an amorphous or other crystalline structure by destroying the zeolite crystal structure of the powder. A method for producing an inorganic antibacterial agent, which comprises: a firing step for converting the inorganic antibacterial agent into a powder; and a pulverizing step for pulverizing the fired product obtained from the previous step into a fine powder with an average particle size of 10 μm or less. 5. The method for producing an inorganic antibacterial agent according to claim 1, wherein the synthetic zeolite powder is a type A zeolite. 6. A resin composition comprising 0.01 to 70 parts by weight of the inorganic antibacterial agent according to claim 1, based on 100 parts by weight of a synthetic resin.