JPH06165904A - Graphite filter and after-treatment thereof - Google Patents

Abstract

PURPOSE:To provide a graphite filter enabling to reduce mixing of graphite powder into a liquid at the time of a separation treatment of blood, etc., by comprising primarily the graphite powder, composing of a carbide body of a blended compact of both graphite powder and organic binder, also providing communicating pores and setting the pore ratio to a specific value. CONSTITUTION:The graphite filter comprises the carbide body of a blended compact of graphite powder (as a principal component) and the organic binder, and it has communicating pores and the porosity is 10-60%. When the graphite powder is oriented in the separating direction as the filter, a passing speed of a product to be separated becomes relatively high compared with thickness as a filter and it has an advantage contributing to the decrease in the processing time. Also as the organic binder, when control of the porosity is considered, a depolymerizable organic matter such as polyethylene, polypropylene and polybutadiene, are preferable as one of the products. Thus, at the time of a separation treatment of blood, etc., mixing of the graphite powder into a liquid can be minimized and the handling is greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite filter containing graphite powder as a main component, which is used for separation treatment of blood by utilizing the inertness of graphite itself, and a post-treatment method.

[0002]

2. Description of the Related Art Blood obtained by separating formed components such as red blood cells by a test using a reagent for clinical diagnosis is sometimes used. As a filter used for separating the formed components, there is a filter made of graphite powder covered with a collodion film.

[0003]

The collodion film is very fragile. The collodion film will be broken if handled with sufficient care. Certainly, since the graphite powder is inactive, it can be considered that the collodion film may be broken and the graphite powder may be mixed into blood. However, it is still desirable to prevent graphite powder from being mixed into blood as much as possible. In addition, it is also desired to reduce the contamination of the surroundings by the graphite powder when the filter is newly used or replaced. The present invention aims to improve such poor handling.

[0004]

A graphite filter containing graphite powder as a main component is made of a carbonized product of a mixed molded product of graphite powder and an organic binder. Here, the carbonized body has continuous pores, and the porosity thereof is 10 to 60%. The graphite powder is integrated with the carbon skeleton closest to the graphite to prevent the graphite powder from being separated alone, that is, "graphite filter mainly composed of graphite powder-
Which is composed of a carbonized product of a molded mixture of graphite powder and an organic binder, has open pores, and has a porosity of 10 to 60.
The above-mentioned problem can be solved by using a graphite filter having a%.

Further, various improvements may be made in order to make the filter function of the carbonized material better. First, it is assumed that the compound has a carbon skeleton derived from the depolymerization type organic substance powder. Further, it is assumed that the graphite powder is oriented in the separation direction as the filter. Furthermore, the diameter distribution of the continuous ventilation holes has a peak within the range of 1 to 300 μm. In addition, it further contains a hydrophilic inorganic powder. These can also be adopted in appropriate combination. For example, the graphite powder is oriented in the separation direction as a filter, and the diameter distribution of the communicating air holes has a peak in a portion of 1 to 300 μm. In addition, it is also preferable to perform hydrophilic treatment as a post-treatment.

A detailed description will be given below through an example of the manufacturing method. In order to easily obtain the graphite filter of the present invention, graphite powder and an organic binder, a reinforcing material such as carbon fiber or graphite fiber, a plasticizer, a solvent and the like are optionally used, and these are mixed in a mixer. -, Roll mill, kneader or the like, or mixed by a mechanochemical method, etc., and molded into a tablet or other desired shape by an appropriate molding method such as extrusion molding, injection molding, press molding, hydrostatic molding, This mixed molded product may be heat-treated in a non-oxidizing atmosphere to carbonize the organic binder to form open pores having a porosity of 10 to 60%.

Here, as the graphite powder, flake graphite,
Natural graphite such as scaly graphite and earth graphite, or
It is preferable to select artificial graphite having high graphite purity as much as possible. Impurities are less likely to be mixed with blood, such as when used for separating formed particles of blood. Further, when this graphite powder is oriented in the separation direction as a filter, the separation speed is relatively high compared to the thickness as a filter, but the passing speed is relatively high, which has the advantage of contributing to shortening the operation time. is there. For that purpose, the thickness direction of the filter may be determined by utilizing the nature of graphite that is easily oriented during molding. For example, a long extruded product in which graphite is oriented in the extrusion direction may be cut into pieces according to the thickness of the filter.

The organic binder can be selected from various materials such as natural and synthetic resins, rubbers, thermosetting initial condensates, asphalt, pitch, tar, and the like.
Resin, acrylic resin, urea resin, melamine resin, polyester resin, furan resin, polyvinyl alcohol, polyacrylamide, butyl rubber, polyvinyl chloride, chlorinated polyethylene, polyvinylidene chloride and the like.
They may be used alone or in combination of two or more kinds. The strength of the molded product increases depending on the amount used, but on the other hand, the active sites as carbides increase, so it is generally preferable not to use too much.

Considering this point and the porosity control,
One of the preferable organic binders is a depolymerization type organic substance. For example, polyethylene, polypropylene, polybutadiene, polyisobutylene, polystyrene, polymethamethylstyrene, polymethylmethacrylate, polyethylmethacrylate, polyacrylic acid ester, poly-α-deuterostyrene, nylon and the like. It is preferably used in powder form. Since the continuous pores largely depend on the state of existence of the organic binder in the molded mixture of the graphite powder and the organic binder, the pores can be made uniform.

However, this depolymerized organic substance can be positively utilized as a control material for forming pores, that is, a pore forming material. For example, when a fibrous material is used, pores can also be formed in a shape and size corresponding to the portion of the molded article where the fibrous material was present. Even if they do not have the same shape and size due to shrinkage during carbonization, depending on what is separated, for example, one with a size of 1 μm or less or several hundred μ
If it is used such as m, the pores corresponding to this can be obtained. 1 to 30 mentioned above
It is easy to form a continuous ventilation hole having a diameter distribution having a peak in a considerably large portion of 0 μm. It should be noted that this large-diameter portion serves as a temporary storage place for the separated one that is supplied to the small pores in the vicinity of the filter, depending on the kind of the separated one. It is also possible to form through-pores in the separation direction by using a long fibrous material, orienting and molding the fibrous material, and dissipating the organic binding material at a temperature equal to or higher than the temperature at which decomposition and carbonization starts to be exhausted.

The passage speed of the substance to be separated can be controlled by controlling the pore size as described above. However, since the graphite itself is hydrophobic, when the substance to be separated is an aqueous liquid,
It is also preferable to positively impart hydrophilicity. Powders and spheres such as anhydrous silica and amorphous silica (commercial products include Aerosil manufactured by Nippon Aerosil Co., Ltd., Fine Seal manufactured by Tokuyama Soda Co., Ltd., God Ball manufactured by Takara Kosan Co., Ltd., etc. ), Or a hydrophilic inorganic powder such as a metal oxide powder, may be used as one of the materials in an appropriate amount, generally about 5 to 30% by weight, depending on the separation liquid. Further, as a method not depending on the use as such a material, a hydrophilic treatment may be applied as a post-treatment. For example, a graphite filter is impregnated with a colloidal solution of silicic acid anhydride to form a film, or a treatment with an acid or an alkali is performed. Here, as the acid, common ones such as hydrochloric acid, nitric acid and sulfuric acid, and as the alkali, sodium hydroxide, potassium hydroxide, calcium hydroxide and the like can be used. If the concentration is too high, the graphite filter will be consumed.
Generally, about 5 to 30% is preferable. After the treatment, it is thoroughly washed with water and dried. By the way, if one that remains after the heat treatment for carbonization and dissolves in these liquids is one of the materials, it can be used as a pore-forming material.

Since the manufacturing method is appropriate, other methods may be used. Also in the above-mentioned method, the surface of the graphite powder can be appropriately coated with a depolymerization type organic substance or a fine powder of anhydrous silica can be attached in advance. In addition, the graphite filter of the present invention may be embedded in a collodion membrane for use. Even if the collodion film is broken, the graphite powder is prevented from being mixed in the liquid.

[0013]

【Example】

<Example 1> Graphite powder CP (natural graphite graphite manufactured by Nippon Graphite Industry Co., Ltd .; average particle size 7.0 μm, particle size range 1 to 45 μm)
m) 7 parts by weight and 3 parts by weight of polyvinyl chloride were uniformly dispersed and mixed in a mixer, and then press-formed to have a diameter of 10 m.
A tablet-shaped molded product having a thickness of m and a thickness of 1 mm was obtained. This molded product was heated in air from room temperature to 300 ° C. at a rate of about 1 ° C./minute, and then heat-treated in a nitrogen atmosphere at a maximum temperature of 600 ° C. for 1 hour. The obtained product had continuous pores, and its porosity was 23.9% (measured according to JIS R 2205).

<Example 2> In Example 1, the amount of graphite powder CP used was changed from 7 parts by weight to 6 parts by weight, and the amount of polyvinyl chloride used was changed from 3 parts by weight to 2 parts by weight. The same procedure as in Example 1 was carried out except that 2 parts by weight (polymethylmethacrylate beads manufactured by Mitsubishi Rayon Co., Ltd .; particle size range: 10 to 50 μm) were used together.
(Porosity is 31.8%)

Example 3 In Example 1, the amount of graphite powder CP used was changed from 7 parts by weight to 9 parts by weight, and 1 part by weight of acrycon (described above) was used instead of 3 parts by weight of polyvinyl chloride. Except for the above, the same procedure as in Example 1 was performed.
(Porosity is 11.4%)

<Example 4> The amount of graphite powder CP used in Example 1 was changed from 7 parts by weight to 8 parts by weight, and MP-1000 (manufactured by Soken Chemical Co., Ltd.) was used instead of 3 parts by weight of polyvinyl chloride. Example 1 except that 2 parts by weight of polymethylmethacrylate ultrafine powder manufactured by K.K .; particle size 0.4 μm) was used.
Same as. (Porosity is 28.8%)

<Example 5> In Example 1, the amount of the graphite powder CP used was changed from 7 parts by weight to 6 parts by weight, and instead of 3 parts by weight of polyvinyl chloride, a flow beads LE-10 was used.
The same procedure as in Example 1 was carried out except that 4 parts by weight of 80 (spherical polyethylene manufactured by Sumitomo Seika Chemicals; particle size range: 2 to 10 μm) was used. (Porosity is 52.3%)

<Sixth Embodiment> In the fourth embodiment, MP-1
000 from Freeze CL-2507 (Sumitomo Seika Chemicals Ltd.)
Made spherical polyethylene; particle size range 100-250μ
m) Same as Example 4 except that 2 parts by weight was used. (Porosity is 19.5%)

Example 7 Graphite powder CP 25 parts by weight Polyvinyl chloride 30 parts by weight Dioctyl phthalate (plasticizer) 15 parts by weight Stearate (stabilizer) 1 part by weight Methyl ethyl ketone (solvent) 50 parts by weight The above-mentioned compounded materials Was uniformly kneaded with 3 rolls and extruded to form a columnar product having a diameter of 10 mm, and cut into a disc-shaped product having a thickness of 1 mm, which was subjected to the same heat treatment as in Example 1. (Porosity is 36.3%)

Example 8 The procedure of Example 7 was repeated except that 10 parts by weight of nylon fiber (15 μm diameter, 500 μm length) was further used as a material.
(The porosity is 54.8%, and the peak of the pore size distribution is in the approximately 14 μm portion)

Example 9 The procedure of Example 7 was repeated, except that 20 parts by weight of nylon fiber (5 μm diameter, 1500 μm length) was further used as a material.
(The porosity is 48.2%, and there is a peak of pore size distribution in about 5 μm portion)

<Embodiment 10> In Embodiment 7, Aerosil 300 (anhydrous silica manufactured by Nippon Aerosil Co., Ltd.) 5
Example 7 except that parts by weight were also used as material
Same as. (Porosity is 31.2%)

<Example 11> In Example 7, Godball E-2C (spherical porous silica produced by Takara Kosan Co., Ltd .;
The procedure of Example 7 was repeated, except that 5 parts by weight of a particle diameter range of 0.2 to 2 μm) was further used as a material. (Porosity is 32.7%)

Example 12 Seno-Tex 30 (anhydrous silicic acid colloidal solution manufactured by Nissan Chemical Industries, Ltd .; silicic acid anhydride content 30%) 10% aqueous solution was sufficiently impregnated with respect to that obtained in Example 7. Then, it dried and formed the film. (Porosity is 33.1%)

Example 13 In Example 7, graphite powder CP was replaced with graphite powder CSSP (natural scaly graphite powder manufactured by Nippon Graphite Industry Co., Ltd .; average particle size 1.0 μm, particle size range 0.1).
.About.5 .mu.m), except that the same procedure as in Example 7 was performed. (Porosity is 25.6%)

<Example 14> The product obtained in Example 7 was immersed in an aqueous solution of 10% hydrochloric acid for 30 minutes (using an ultrasonic cleaner).
After that, thoroughly wash with water (use ultrasonic cleaner), 110
A drying process was performed at ° C.

<Example 15> The same procedure as in Example 14 was carried out except that a 10% aqueous solution of hydrochloric acid was used instead of the 10% aqueous solution of hydrochloric acid.

[0028]

When the graphite filter of the present invention is used,
It is possible to minimize the risk of graphite powder being mixed into the liquid during the separation treatment of liquid such as blood, and the handling property is also very good.

Claims (6)

[Claims] 1. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and an organic binder, and has open pores and a porosity of 10 to 60%.
Is a graphite filter. 2. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and depolymerization type organic material powder, and has open pores and a porosity of 10%.
~ 60% graphite filter. 3. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and an organic binder and has open pores with a porosity of 10 to 60%.
And a graphite filter in which the graphite powder is oriented in a separation direction as a filter. 4. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and an organic binder, and has a diameter distribution having a peak within a range of 1 to 300 μm. A graphite filter having continuous ventilation holes and a porosity of 10 to 60%. 5. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and an organic binder and has open pores and a porosity of 10 to 60%.
And a graphite filter containing a hydrophilic inorganic powder. 6. A graphite filter containing graphite powder as a main component, which is made of a carbonized product of a mixed molded product of graphite powder and an organic binder and has open pores and a porosity of 10 to 60%.
A post-treatment method for a graphite filter, which comprises subjecting the following to a hydrophilic treatment.