JPH03207414A - Calcium phosphate-based filter - Google Patents

Abstract

PURPOSE:To collect even gases, bacteria and viruses by forming a polymeric matrix in which the grains of the calcium phosphate-based compd. with its Ca - to - P ratio controlled to 1.0-2.0 are dispersed into a sheet which is used as the filter. CONSTITUTION:When paper is used as the matrix, a specified amt. of calcium phosphate grains are dispersed in a pulp slurry, and the slurry is made sheet to produce the filter. Meanwhile, when a nonwoven fabric is used, a specified amt. of a calcium phosphate-based compd. is added when the fabric is produced to form the filter. Since the grains of the calcium phosphate-based compd. with its Ca - to - P ratio controlled to 1.0-2.0 are dispersed in the org. polymeric matrix, the obtained calcium phosphate-based filter is of great use as the filter for the air cleaner, water purifier and deodorizer and the filter for bacteria and viruses.

Description

Detailed Description of the Invention "Field of Application" The present invention is used to capture biopolymer substances, bacteria, viruses, animal and plant cells, harmful gases, bad odors, dust, mists, etc. in gases or liquids, and to prevent other harmful substances. Concerning filters that can pass through.

"Prior art and its problems" Conventionally, known filter materials include fibrous materials such as paper and mouth cloth, granular materials such as activated carbon, clay, gravel, and diatomaceous earth, and porous materials such as porous ceramics. ing. Most of these filters trap solid substances, and an appropriate filter is selected and used from the above filters depending on the object to be treated. Activated carbon is often used because it has the ability to adsorb a wide range of substances, but it does not adsorb oil-soluble substances or malodorous substances such as ammonia, so it is used for filtration of gases and liquids containing these substances. It is not possible.

In addition, in recent years, membrane filtration systems using ultrafiltration membranes, reverse osmosis membranes, etc. have been developed, but these are expensive. Further, bacterial filtration devices such as the Zyllo filtration device are known, but they are not only limited to capturing bacteria, but also require the use of reduced pressure or centrifugal force, which is complicated.

Thus, conventionally known filters are limited in what they capture and control or require expensive equipment.

``Object of the Invention'' The present invention provides a filter that is inexpensive, has a simple structure, is easy to handle, and can capture not only solid substances but also gases, bacteria, viruses, animal and plant cells, etc. The purpose is to provide

“Composition of the invention” The calcium phosphate filter according to the present invention has Ca/P in the organic polymer matrix formed into a sheet shape.
It is characterized by containing dispersed particles of a calcium phosphate compound having a ratio of 1.0 to 2.0.

Examples of the organic polymer matrix that can be used in the present invention include paper (cellulose), nonwoven fabric, and plastic foam (eg, urethane foam). The matrix used in the present invention must have voids containing dispersed particles of the calcium phosphate compound, but in the case of paper or nonwoven fabric, the voids between the fibers may be sufficient.
Plastic foam needs to have continuous pores. The size of these fiber gaps and pores is not particularly limited, and can be selected appropriately depending on the size and amount of particles to be dispersed, but they allow the gas or liquid to pass through, and during the passage, calcium phosphate It is necessary to be able to contact the particles of the system compound. Further, the thickness of the sheets can be appropriately selected depending on the purpose of use of the filter, and sheets as thin as .mu.m can be stacked and used in some cases.

The calcium phosphate compound used in the present invention is 1.0 to
There is no particular restriction as long as it has a Ca/P ratio of 2.0, and examples thereof include hydroxyabatite, tricalcium phosphate, tetracalcium phosphate, and mixtures thereof.

In the present invention, these calcium phosphate compounds have a particle size of 0. Used as particles of 1 to 100 μm. If the particle size is less than 0.1 μm, the particles will aggregate and be difficult to disperse, and if the particle size exceeds 100 μm, it will be difficult to adhere and carry in the matrix. The appropriate particle size is influenced by the matrix used, and for example, when paper is used as the matrix, it is preferably 1 to 30 μm. If the particle size is less than 1 μm, it will fall off the rope of the paper machine along with water during paper making, and if it exceeds 30 μm, it will be too heavy and difficult to disperse uniformly. Furthermore, the particles of the calcium phosphate compound are preferably porous. Porous particles of a calcium phosphate compound can be produced by various methods using crystal particles of a calcium phosphate compound that have been wet coalesced by a known method as a raw material. For example, a slurry in which raw material particles are suspended is directly granulated into secondary particles by spray drying, or additives such as a viscosity modifier, pyrolyzable organic compound particles, or fibers are added to this slurry and then spray dried. It is granulated into secondary particles by methods such as. These secondary particles are suspended in a slurry again and wet-molded, or formed into a block by dry-molding using pressure. At that time, an organic compound that is thermally decomposed by burning to form pores may be added. Even without additives, the pore size can be controlled by adjusting other conditions such as firing temperature. The obtained block body is 5 0
Burns out in the temperature range of 0'C to 1300C. 500
If the temperature is less than °C, the thermal decomposition of the organic compound and the sintering of the block will not be sufficiently carried out. Furthermore, if the burning is performed at a high temperature exceeding 1300°C, the sintered body may become too dense or the calcium phosphate may decompose. After the block body burnt out in this manner is crushed, it can be classified to obtain particles of a required particle size.

When using porous particles, the pore size varies depending on the target substance to be separated, but especially when the purpose is to separate microorganisms such as viruses, the pore size needs to be 0.01 μm or more. be.

In addition, the porosity of the porous particles is preferably 10 to 75%; if it is less than 10%, sufficient surface area and water retention cannot be obtained, and if it exceeds 75%, it cannot be used as porous particles. Strength cannot be obtained.

The surface of the calcium phosphate particles used in the present invention contains one or more of, for example, biologically derived hyaluronic acid, chondroitin sulfate, chitin derivatives, fibronectin, osteonectin, mucopolysaccharides, proteins, and derivatives thereof. It is also possible to partially adsorb particles and modulate the physicochemical or immunological properties of the particle surface, thereby skillfully changing the adsorption activity.

When producing the filter of the present invention using paper or nonwoven fabric as a matrix, particles of a calcium phosphate compound can be added at the time of production. For example, when using paper as a matrix, the filter of the present invention can be manufactured by dispersing calcium phosphate particles in pulp slurry and making paper. When a nonwoven fabric is used as a matrix, a calcium phosphate compound can be similarly added during the production of the nonwoven fabric. A filter having plastic foam as a matrix can be manufactured by immersing the plastic foam in a slurry of calcium phosphate compound particles and drying it.

Additionally, the filters of the present invention can be perforated, such as with a two-dollar punch, to improve permeability to the gas or liquid to be filtered.

In the present invention, a calcium phosphate compound having a high adsorption effect is dispersed, so even if the matrix is perforated, the object to be separated will not pass through unless the perforations are made too large.

In the calcium phosphate filter of the present invention, the calcium phosphate particles are biopolymer substances in gas or liquid.
It has an adsorption effect on bacteria, viruses, animal and plant cells, harmful gases, malodorous components, dust, mist, etc., so it can be used as a filter in a variety of products. For example, it can be used as a filter in air purifiers, water purifiers, deodorizing devices, bacterial and virus filters, cell separators, serum filters, masks, etc.

Since the filter of the present invention is in the form of a sheet, it can be easily replaced if the adsorption capacity decreases due to use. For example, when used in a mask, the filter of the present invention can be easily attached by sandwiching it between the gauze of a commercially available gauze mask, or by attaching a gauze pocket and placing it inside the gauze mask. It can also be easily replaced. When used in a mask, the filter of the present invention can adsorb bacteria and viruses and prevent them from entering the human body, so it can be expected to have a significant effect during influenza epidemics.

"Examples of the Invention" Next, the present invention will be described in more detail based on Examples, but the present invention is not limited thereto.

Example 1 Average particle size 1. In a slurry, 1000 g of porous hydroxyabatite particles having an average pore diameter of 0.09 μm, having a porosity of 45% and a Ca/P ratio of 1.67 were dispersed in lOOOHl of water containing 20 g of polyvinyl alcohol. Thickness: IO, average pore diameter: 300μm, porosity: 97%
A sheet-like polyurethane foam having continuous pores was immersed, pulled up, and dried at 25°C to produce a filter.

Example 2 Bulb was dispersed in water to prepare a bulp slurry with a concentration of 0.5%, with an average particle size of 6.2 μm, a porosity of 63%, and Ca/
P ratio 1.5, average pore diameter 0. 0.5% by weight of 1 μm porous tricalcium phosphate was added and paper was made by hand using an experimental paper machine. The tricalcium phosphate content of the resulting paper product was 50% by weight.

Example 3 Average particle size 1. 900 g of porous hydroxyapatite particles with an average pore size of 0.09 μm, a porosity of 45%, and a Ca/P ratio of 1.67, and an average particle size of lO. Average pore diameter 1.0μm, porosity 60%, Ca/P ratio 1.67
A double-punch polyester nonwoven fabric (Panelon manufactured by Dynic, weight: 200 g/n?) was added to a slurry in which 100 g of porous hydroxyapatite particles of 100 g were dispersed in 1000 g of a 3 wt% aqueous solution of polyvinyl alcohol.
) was immersed, pulled out, and dried at 25°C to produce a filter. Example 4 Average particle size: 2.2 μm, porosity: 50%, Ca/P ratio: 1.
After mixing 400 g of porous hydroxyapatite particles of No. 67 with an average pore diameter of 0.09 μm with 600 d of a 10% by weight aqueous solution of polyvinyl alcohol, the mixture was adhered by printing onto a polyester nonwoven fabric (Panelon manufactured by Dainic Co., Ltd.).
It was then dried at 25°C to produce a filter. The printing was carried out using a plate having 4 m squares arranged at 11 intervals.

Test Example 1 The filters prepared in Examples 1 to 4 were cut into circles with a diameter of 45 cm, and after mounting them on a filter holder, the apparatus shown in FIG. 1 was constructed. Fig. 1 shows a system diagram of a deodorizing device incorporating the above-mentioned filter. It is connected.

The ammonia gas is sucked from the Tedra bag 1 containing ammonia gas as the original odor while controlling the flow rate with a pump and flow meter 4 connected to the rear stage of the filter holder 2, and after passing through the filter 2a, the ammonia gas is transferred to the rear stage of the flow meter 4. It was collected in Tedravac 5.

At this time, the amount of gas passing through the filter 2a is 10
It was set to 1. Also, the concentration of gas before and after passing through the filter is
The concentration of gas in each Tedra bag containing the original odor and the inhaled gas was determined by measuring with a detection tube method. The results are shown in Table 1.

Table 1 The removal rate in Table 1 indicates what percentage of the ammonia gas in the source was adsorbed by the filter. As is clear from Table 1, depending on the form of the filter, 90% or more of the gas is adsorbed, and the filter of the present invention has an extremely excellent odor removal effect.

Test Example 2 This test example shows an example in which the filters produced in Examples 2 and 3 were used as virus adsorbents. In this test, influenza virus PR8 was used suspended in physiological saline. Moreover, the titer was measured by the following method.

How to measure titer When the influenza virus attaches to red blood cells, the red blood cells agglutinate with each other. Using this reaction, the virus suspension was serially diluted 2 times, 4 times, 8 times, 16 times, etc. with physiological saline (0.9% sodium chloride aqueous solution), and the same amount 0. The titer of the stock solution (liquid before dilution) is evaluated by mixing it with a 4% chicken red blood cell suspension and determining how many times the dilution causes an agglutination reaction.

The filters of Examples 2 and 3, each cut into a circular shape with a diameter of 5o, were attached to a funnel, and a suspension of influenza virus PR8 was poured therein for 3rd time, and the titer of the virus suspension flowing out from the funnel was measured by the method described above. Submit the results in the second section below.
Shown in the table.

The titer in Table 2 is proportional to the concentration of virus in each effluent before dilution, and from Table 2 it can be seen that the concentration of virus that passed through the filter of Example 2 was 1/32 of the concentration before passing through the filter. This means that the virus concentration in the virus passed through the filter of Example 3 was reduced to 1/4. In other words, the virus was adsorbed to the filter.

"Effects of the Invention" The calcium phosphate filter of the present invention is inexpensive, has a simple structure, is easy to manufacture and handle, and can not only separate solid substances, but also gaseous substances, bacteria, viruses, etc.
Animal and plant cells can also be captured at the same time. Furthermore, since the filter of the present invention is in the form of a sheet, it is easy to attach and detach, and can be easily replaced whenever the adsorption capacity decreases due to use.

Therefore, the filter of the present invention can be used as a filter in various filtration/separation devices such as air purifiers, water purifiers, deodorizing devices, bacterial and virus filtration devices, cell separators, serum filters, masks, etc. I can do it.

[Brief explanation of drawings]

Figure 1 is a system diagram of a deodorizing device incorporating the filter of the present invention. Explanation of symbols 1 and 5... Tedra bag, 2... Filter holder, 2a... Filter, 3... Pump, 4 - Flow meter

Claims (1)

[Claims] 1. A calcium phosphate system characterized by containing particles of a calcium phosphate system compound having a Ca/P ratio of 1.0 to 2.0 dispersed in an organic polymer material matrix formed into a sheet shape. filter. 2. The calcium phosphate filter according to claim 1, wherein the organic polymer matrix is paper, nonwoven fabric, or plastic foam. 3. Particles of calcium phosphate compound are 0.1 to 100
The calcium phosphate filter according to claim 1 or 2, which has a particle size of μm. 4. The calcium phosphate filter according to claim 1, 2 or 3, wherein the particles are porous.