JP4610314B2 - Filter member and liquid bottle using the same - Google Patents

Description

  The present invention relates to a filter member having air permeability and a liquid bottle capable of keeping the internal air pressure and the external air pressure substantially the same by using the filter member as a ventilation filter while preventing permeation of liquid.

  Conventionally, porous films such as polytetrafluoroethylene (PTFE) porous bodies, nonwoven fabrics, meshes, and the like have been used as gas permeable materials having an effect of preventing liquid leakage. Recently, these gas permeable materials are used in many fields as a ventilation filter by utilizing the oil repellency and water repellency.

  The ventilation filter is generally provided for the purpose of waterproofing and dust removal at the vent of various sealed liquid bottles. For example, a camera is used for zooming and focusing, and an electronic device and precision machine are used to reduce fluctuations in internal pressure due to temperature changes.

  In addition, liquid bottles such as baby bottles are used to introduce air into the inside of the bottle that has been sucked and decompressed, or to use medical liquid storage liquid bottles such as infusion sets that inject drugs into the living body, or to use a pressure drop In order to make the air pressure in the liquid bottle equal to the external air pressure, the injection device for the antiseptic agent and the like requires an air vent, and an oil repellent / water repellent air filter is used for these air vents. These filters need to have a function of allowing gas to pass through without allowing external or internal liquid / water droplets to pass through.

  However, like waterproof breathable filters for electrical components mounted on automobiles, the filter members used for vent filters are exposed to harsh environments where there is a lot of oil vapor in various automobile oils such as engine oil in the engine room. It was. Also, in general living environment, precision parts and electronic parts are incorporated in a camera or the like, and a filter member is provided to maintain air permeability, and the filter member includes a surfactant such as a kitchen detergent. It often comes into contact with liquids, oils and fats, or body fats.

  Furthermore, when a filter member is used for a liquid bottle for injection of medicine, the medicine injected into the liquid bottle may be strongly acidic, or strongly alkaline, and may be an organic solvent such as alcohol or acetone. Moreover, when using for the infusion set used for a human body, it may be necessary to boil a filter member at high temperature as a sterilization process.

  Furthermore, as shown in FIG. 5, in the inkjet ink liquid bottle 101, an assembly 102 obtained by hydrophilic treatment of an olefin resin or the like is laid inside the liquid bottle to impregnate the liquid, and a space is formed between the gas intake port 103. It is disclosed that the liquid is blocked without leaking by being installed so as to be held, and the differential pressure is adjusted so that the gas can be taken into the inside from the gas intake port 103 (see, for example, Patent Document 1). .

  In addition, as shown in FIG. 6, a water repellent film 106 such as polytetrafluoroethylene is attached to the four corners of the liquid bottle 101, and a method such as taking air is taken to measure the liquid repellent and reduce the difference between the external pressure and the internal pressure. This is also disclosed (see, for example, Patent Document 2).

Further, as shown in FIG. 7, laser processing is performed on the plastic film 105 to form an independent uniform air hole 104, thereby allowing the passage of gas while the liquid is prevented from passing by the capillary force. It has also been disclosed that liquid repellent ventilation is obtained by performing a liquid repellent treatment (see, for example, Patent Document 3).
JP 2001-162824 A JP 2003-266722 A JP 2003-88733 A

However, the filter member has been used in this way in a variety of contexts, the oil and surfactant is brought into contact with the breathable filter water resistance of the filter, and a problem that ventilation is lost, also acidic Or when using a filter member for the liquid bottle which uses an alkaline liquid or an organic solvent, there existed a subject that a filter member corroded by these liquids.

  Further, when it is necessary to perform a high temperature treatment such as boiling on the filter member, the filter member expands due to the high temperature treatment, and pores inside the filter member are closed, and finally the air permeability is lost. There was a problem that it ended up.

  In addition, in the ink jet ink liquid bottle 101 of Patent Document 1, it is necessary to fill a large portion of the liquid bottle 101 with an assembly 102 made of resin in order to ensure the liquid blocking property and ventilation, and the ink capacity to be filled is limited. In addition, there is a problem that the ink that has become hydrophilic and is taken into the resin is not released.

  Further, in the method of attaching the water repellent film 106 disclosed in Patent Document 2 to the four corners of the liquid bottle 101, when the surface tension of the liquid falls below 40 mN / m, the existing water repellent film 106 is wetted and the water repellent film 106 is repelled. Due to the water film 106, there is a problem in that the liquid holding force due to the capillary force of the capillary phenomenon is small, so that it leaks outside through the pores.

  Furthermore, according to the method disclosed in Patent Document 3, when the surface tension of the liquid is less than 40 mN / m, the existing water-repellent film is wetted when the vent 104 subjected to water-repellent treatment by laser processing is below 40 mN / m. However, there is a problem of leaking to the outside, and none of the conventional liquid bottles using the filter member is satisfactory.

  Accordingly, the present invention provides a highly durable filter member capable of ensuring air permeability with respect to liquids containing oil and surfactant, acidic and alkaline liquids, organic solvents or hot water, and liquids with low surface tension, and the filter member It aims at providing the liquid bottle which comprises air permeability and the liquid leakage prevention effect.

The filter member of the present invention is composed of at least one of alumina, mullite, zirconia, forsterite, silica, cordierite and titania, and has an average pore diameter of 5 to 200 μm and an average crystal grain size of 0.02 to 1 mm. There is a porous ceramic in which the pore diameter of one surface is larger than the pore diameter of the other surface, and the liquid contained from the pores of the one surface of the porous ceramic is retained inside. In addition to being configured, it is characterized in that the gas entering from the pores of the one surface is vented from the other surface .

Liquid bottle of the present invention, one of the chamber housing the liquid, can be supplied and discharged, and the other chamber will comprise ambient air breathable vent, the said one compartment and said other chamber It is characterized by being separated by a filter member made of porous ceramic.

  Further, the liquid bottle is characterized in that the filter member is held by a support provided in the chamber of the liquid bottle.

The filter member of the present invention is composed of at least one of alumina, mullite, zirconia, forsterite, silica, cordierite and titania, and has an average pore diameter of 5 to 200 μm and an average crystal grain size of 0.02 to 1 mm. Yes, it is made of a porous ceramic whose pore diameter on one side is larger than the pore diameter on the other side, so that the liquid contained from the pores on one side of the porous ceramic can be retained inside In addition, the gas entering from the pores on one surface is vented from the other surface. Since it is made of such a porous ceramic, its hydrophilicity and oleophilicity are relatively high, so that it wets well with water-based and oil-based liquids. Since it holds and functions like a lid, the gas layer and the liquid layer can be easily separated. Furthermore, even if the above-described ceramic is made porous, sufficient strength is obtained as a lid filter member, and impact resistance is also improved. Moreover, the pore diameter and porosity can be controlled by the raw material particle diameter and the firing temperature, and it is possible to cope with liquids having various surface tensions. Further, in order to allow the porous ceramic to flow in both directions, when the porous ceramic is used as a liquid bottle lid as a filter member, the internal and external pressure difference of the container can be reduced, It is possible to prevent liquid from leaking out of the container. In addition, the average pore diameter can be controlled to a desired value, and pores necessary for efficiently holding the liquid can be formed in the porous ceramic. Furthermore, some have acid or alkali may not be corroded be used as a filter member using an organic solvent, a problem that pores clogged air permeability is decreased does not occur even when further subjected to high temperature processing. In addition, the liquid entering from the pores on one surface is configured to be held inside, and the gas entering from the pores on one surface is vented from the other surface. Can be adsorbed and held efficiently by the capillary force generated in the step 1, and air permeability can be ensured.
In addition, the filter member of the present invention is made of porous ceramic, and a liquid affinity agent is provided on a part of the particles from the surface so that the liquid entering from the pores on one surface can be held inside, and The gas entering from the pores of the surface is vented from the other surface. Since it is made of such a porous ceramic, it does not corrode even when used as a filter member using an acid, alkali or organic solvent, and even when subjected to a high temperature treatment, the pores are closed and the air permeability is lowered. Does not occur. In addition, the liquid entering from the pores on one surface is configured to be held inside, and the gas entering from the pores on one surface is vented from the other surface. The capillarity generated by the capillaries can be efficiently adsorbed and retained, and air permeability can be ensured.Also, there are many opportunities to contact the liquid near the surface, so that the lipophilic / hydrophilic effect is promoted and the liquid suction effect is more effective. Get higher.

 Moreover, since the porous ceramic is a porous ceramic made of at least one of alumina, mullite, zirconia, forsterite, silica, cordierite, and titania, the hydrophilicity and lipophilicity are relatively high. Since the liquid has good wettability, the liquid is uniformly filled in the pores to hold the liquid and function like a lid, so that the gas layer and the liquid layer can be easily separated. Furthermore, even if the above-described ceramic is made porous, sufficient strength is obtained as a lid filter member, and impact resistance is also improved. Moreover, the pore diameter and porosity can be controlled by the raw material particle diameter and the firing temperature, and it is possible to cope with liquids having various surface tensions.

The liquid bottle of the present invention can store, supply, and discharge liquid in one chamber, and has a vent in the other chamber that can vent air and the other chamber . because it is constituted by separated by the filter member of the present invention, the inner external pressure difference to secure the inside and outside of the vent of the liquid bottle with the outflow of liquid to penetrate the inside of the filter element to the outside of the liquid bottles can proof Gukoto Can be relaxed.

 Furthermore, if the filter member of the liquid bottle is held by a support provided in the interior of the liquid bottle, the liquid bottle has durability against various liquids, and further allows only gas to pass in both directions. Excellent gas permeability and liquid leakage prevention effect.

 As described above, the liquid bottle using the filter member of the present invention as a ventilation filter has high oil resistance, solvent resistance, chemical resistance, and heat resistance. By holding the liquid in the pores, only the gas does not pass through the liquid. Gas in both directions without passing the liquid in the presence of at least one of oil, surfactant, organic solvent, acidic or alkaline liquid, or even at high temperatures. It is possible and possible.

 FIG. 1 shows a cross-sectional view of a filter member 1 which is an example of the present invention.

The filter member 1 of the present invention is composed of at least one of alumina, mullite, zirconia, forsterite, silica, cordierite and titania, has an average pore diameter of 5 to 200 μm and an average crystal grain size of 0.02 to 1 mm. And the pore diameter of the pores existing on one surface is larger than the pore diameter of the pores existing on the other surface, and the liquid entered from the pores 3 on one surface 1a of the porous ceramic 2 4 is configured to be held inside, and the gas 5 entering from the pores 3 on the one surface 1a is vented from the one surface 1b.

 Below, the filter member 1 of this invention hold | maintains the liquid 4 which entered from the pore 3 of the one surface 1a of the porous ceramic 2 inside, and ventilates from one surface 1b in full detail.

 When the liquid 4 is brought into contact with one surface 1 a of the porous ceramic 2, the one surface 1 a is wetted with respect to the liquid 4. At the same time, the pores 3 of the porous ceramic 2 also wet with the liquid 4. Here, in the pores 3, capillary action becomes a driving force, and the liquid 4 is sucked into the pores 3 to fill the internal pores of the porous ceramic 2 with the liquid 4. Since the liquid 4 filled in the pores 3 is wetted with the wall surfaces of the pores 3 and moves so that the contact area between the pores 3 and the liquid 4 increases, the details of the pores 3 are reached. The liquid 4 can be held in the pores 3 by the capillary force. Then, when the pores are filled with the liquid 4 to some extent, the driving force due to the capillary action is lost, so that the absorption of the liquid into the pores stops. Thereby, even if the liquid 4 that has been in contact is separated from the filter member 1, the liquid 4 is held in the pores 3 by capillary force, so that it behaves like a lid of a container and has a function of blocking the inside and outside of the container. It becomes like this. A pressure difference (differential pressure) is generated between one surface 1a and the other surface 1b of the porous ceramic 2 constituting the filter member 1, that is, the pressure applied to the one surface 1a is more than the pressure applied to the other surface 1b. When it becomes large, the filter member 1 comes to ventilate the gas 5. This occurs because the differential pressure exceeds the capillary force that holds the liquid 4. At the same time, the liquid 4 held in the pores 3 moves to the other surface 1 b and is adsorbed and held on the surface. The The gas 5 is ventilated by passing through the pores 3 that are vacant by the movement of the liquid 4. When the pressure difference disappears, it is more stable to be held by the capillary force than to be adsorbed to the other surface 1b, so that the liquid 4 that has moved to the other surface 1b is again held in the pores 3 by the capillary force. Will come to be.

The porous ceramic 2, at least for a portion in contact with the liquid 4, depending on the nature possessed by the liquid 4, important that a material having oil resistance, solvent resistance, chemical resistance and heat resistance It is. Specifically, alumina, mullite, zirconia, forsterite, silica, Rukoto such at least one or more selected from the group of cordierite and titania is important. It is desirable to be made of ceramics containing 50% or more, particularly 70% or more, and more preferably 90% or more. Of these, alumina porous ceramic , silica porous ceramic, and cordierite porous ceramic are preferred from the viewpoint of low cost.

 And an alumina porous ceramic is more preferable at the point with high chemical resistance with respect to oil, a solvent, an acid, or an alkali. In view of the stability of the crystal structure against high-temperature steam, this alumina is preferably α-alumina.

Furthermore, it is important that the average pore diameter of the porous ceramic 2 is 5 to 200 μm in order to exhibit sufficient air permeability and prevention of liquid leakage . In particular, when the thickness is 5 to 80 μm, and further 10 to 50 μm, it is possible to generate a capillary force that can sufficiently hold the liquid 4 in the pores 3, and to reduce the one surface 1 a and the other surface 1 b of the filter member 1. If the differential pressure is generated, it is preferable because gas can be easily vented. On the other hand, when the average pore diameter is larger than 200 [mu] m, because the pores 3 increases, the liquid 4 is or occurs that can not be brought into contact with the wall surface of the pores 3, also, since the capillary force holding the liquid 4 is lowered, the porous There is a possibility of leaking from the other surface 1b through the ceramic 2. Further, the average pore diameter is 5μm smaller, since the capillary power becomes stronger, even the pressure difference occurs between the one surface 1a and the other surface 1b of the filter member 1, required to permit passage of gas 5 Since the differential pressure becomes extremely high, the air permeability of the gas 5 may decrease. In order to enhance the suction effect of the liquid 4 and prevent the liquid 4 that moves when the gas 5 is vented from leaking out of the other surface 1b, the pore diameter of the pores 3 existing on the one surface 1a. Is preferably larger than the pore diameter of the pores 3 present on the other surface 1b.

Furthermore, it is important that the average crystal grain size of the porous ceramic 2 is in the range of 0.02 to 1 mm. This is because when the average crystal grain size is less than 0.02 mm, the capillary phenomenon in the porous ceramic becomes very strong, so when the filter member 1 is provided in the vicinity of the vent of the liquid bottle, the inside of the liquid bottle When venting outside the liquid bottle, a sufficient aeration function may not be obtained unless the differential pressure inside and outside the liquid bottle is very high. On the other hand, when the average crystal grain size exceeds 1 mm, the capillary force decreases, so that the liquid 4 filled in the filter member 1 is easily transmitted even with a small differential pressure generated inside and outside the liquid bottle, and does not function as the filter member 1. There is a case. A more preferable average crystal grain size is 0.03 to 0.15 mm.

 Further, the shape of the porous ceramic 2 as the filter member 1 is not particularly limited, but is preferably a flat plate for ease of production. And in order to have sufficient mechanical strength and ensure gas permeability, it is desirable that the wall thickness is 0.3 to 3 mm, particularly 1 to 2 mm. In order to match the shape of the liquid bottle, at least a part of the porous ceramic may be curved or a pattern may be formed on the surface. Further, the thickness may be changed in accordance with the pressure difference for aeration.

 Further, the contact angle between the porous ceramic 2 constituting the filter member 1 and the liquid 4 is preferably 90 degrees or less. As a result, the interfacial tension of the liquid is lowered and the wettability of the liquid 4 with respect to the wall surface of the pore 3 is improved, so that the contact area between the liquid 4 and the wall surface of the pore 3 is increased. It can be adsorbed and held. On the other hand, when the contact angle exceeds 90 degrees, the wettability between the porous ceramic 2 and the liquid 4 is remarkably reduced, and the driving force for feeding the solution into the pores inside the porous ceramic due to the capillary phenomenon is reduced. Since the liquid repellency is generated in 3, the filling of the liquid 4 into the pores is uneven, and the liquid 4 cannot be held efficiently. The contact angle can be measured by, for example, using a static contact angle analyzer (CA-X manufactured by Kyowa Interface Science Co., Ltd.), dropping 10 μl of liquid on the surface of the porous ceramic 2 and performing image processing.

 The filter member 1 of the present invention uses the porous ceramic 2 in order to combine the chemical resistance, heat resistance, and durability as described above, but depending on the environment to which the filter member 1 is exposed, A liquid affinity agent 6 having a high affinity for the predetermined liquid 4 may be provided in at least a part of the pores 3 of the porous ceramic 2. As a result, the contact angle θ between the liquid 4 and the liquid affinity agent 6 becomes extremely small, and at the same time the surface tension of the liquid becomes low. The liquid 4 gets wet with the liquid affinity agent 6 and adsorbs the liquid 4 on the walls of the pores 3. And easier to hold.

 Here, the term “a part in the pore” means a part of the pore wall and includes a part in contact with the liquid 4. For example, as shown in FIG. 2, the particles 2a constituting the porous ceramic 2 are three-dimensionally connected, and the liquid affinity agent 6 is provided on at least a part of the particles 2a. And the pore 3 which consists of the space | gap between the particle | grains 2a and between the particle | grains 2a and the liquid affinity agent 6 is formed. The liquid affinity agent 6 may be provided on at least a part of the porous ceramic 2, but it is preferable that the liquid affinity agent 6 is provided up to the pores 3 existing in the depth direction of 0.5 mm or more from the surface of the filter member 1. . Since the vicinity of the surface has many opportunities to come into contact with the liquid, the lipophilic / hydrophilic effect is promoted, and the effect of sucking the liquid becomes higher. In particular, the liquid affinity agent 6 is most preferably provided over the entire porous ceramic 2 in order to extend the life by extending the liquid suction effect for a long time and to enhance the durability and reliability of the lipophilic / hydrophilic effect. preferable.

 Furthermore, in order to effectively prevent liquid leakage, it is preferable to set the pores small so that the capillary phenomenon becomes large, and it is preferable to increase the thickness of the porous ceramic. In order to increase the gas permeability, it is preferable to set the capillary phenomenon small, and it is preferable to reduce the thickness of the porous ceramic. That is, it is important to balance the above according to the surface tension of the liquid used.

 The liquid affinity agent 6 depends on the liquid to be used, but if it is an oil or fat, it has lipophilicity, if it is water or water liquid it has hydrophilicity, and if it is an organic solvent, it is an organic solvent. Those having high affinity can be used. For example, when the liquid 4 is water, examples of the liquid affinity agent 6 include a polymer containing titanium oxide, or an affinity agent having a silanol group which is a hydrophilic functional group.

 As described above, the filter member of the present invention has a feature that gas permeates, but liquid does not permeate, and ensures air permeability of the liquid bottle while maintaining the liquid leakage prevention property. It can be suitably used as a liquid bottle capable of maintaining a constant pressure. The filter member of the present invention can be applied to any field as long as it is used in a portion having a possibility of coming into contact with a liquid and requires air permeability.

 Next, the manufacturing method of the filter member of this invention is demonstrated.

First, a porous ceramic is prepared. As described above, an alumina porous ceramic having an average pore diameter of 5 to 200 μm is used as the porous ceramic, but a porosity of 20 to 50% is preferable.

 The method for producing the porous ceramic is to classify raw materials having an average particle size of 0.02 to 1 mm according to the purpose, add a sintering aid as necessary, and extrude by kneading with a binder, or injection molding, The target shape may be obtained by a doctor blade method or the like, and if it is a simple shape, it may be formed by granulation, followed by powder pressing, isostatic pressing, or the like. Thereafter, the filter member 1 made of the porous ceramic 2 can be obtained by firing at an optimum temperature. Here, among the ceramics constituting the porous ceramic, alumina and zirconia have high hydrophilicity, so that the effect of the filter member 1 can be efficiently exhibited with respect to the aqueous liquid 4.

 In addition, although the shape of various raw materials is not limited, it cannot be overemphasized that spherical and uniform particle | grains with a narrow particle size distribution should just be used as a raw material.

 Next, if the liquid affinity agent 6 is to be laid on the porous ceramic, the liquid affinity agent 6 is impregnated into the porous ceramic by a method such as spraying or dipping, and if necessary, aeration treatment, drying, and heat treatment are performed. The filter member 1 may be manufactured by applying. In addition, if the liquid affinity agent 6 is used as a solution in which alcohol having a low surface tension is used, impregnation of the details of the porous ceramic is promoted, and it is easy to coat the liquid affinity agent 6 over a wide area inside the porous ceramic. Become.

 Next, the liquid bottle of the present invention will be described in detail.

 The liquid bottle of the present invention is capable of storing, supplying and discharging liquid in one chamber, and the other chamber is provided with a vent hole that can ventilate the outside air, and separates the one chamber from the other chamber. In order to do so, the filter member of the present invention described above is provided, and since it has both waterproofness and air permeability, the pressure inside the liquid bottle can be reduced without absorbing the liquid by absorbing the liquid. The external atmospheric pressure can be kept substantially the same.

 FIG. 3 shows a liquid bottle 11 as an example of the present invention, which includes a support 12 that divides the liquid bottle 11 into two parts, and has a vent hole 13 in one room, and a liquid level of the liquid 4 to be held. The filter member 1 is configured to have a space 14 between the vent holes 13 and to block the space 14. The frame of the liquid bottle 11 is formed by a liquid or gas impermeable wall. Further, a liquid discharge port 15 is provided, and the liquid 4 is discharged from the discharge port 15, and the gas permeates into the liquid bottle 11 through the filter member 1 and pressure adjustment is performed. If desired, a liquid supply port 16 for supplying a liquid may be provided. When the liquid 4 is supplied from the liquid supply port 16 and the amount of the liquid 4 increases and the pressure in the liquid bottle 11 increases, the gas is discharged to the outside through the filter member 1 to keep the pressure constant. Can do.

Such a liquid bottle can be suitably used as a liquid bottle such as a gasoline tank, an oil tank, an organic solvent tank, a drug tank, a detergent tank, a feeding bottle, and an infusion bottle. For example, by providing the filter member of the present invention at the supply port (cap) of these liquid bottles, the air pressure inside the various liquid bottles and the external air pressure are kept substantially the same without leakage of the liquid filled inside. be able to.
In addition, although one filter member 1 is provided in the liquid bottle 11, it is needless to say that the number of use is not limited, and a desired number of one or three or more may be used.

 In addition, it is equipped with electronic equipment or precision equipment inside, as a liquid bottle having waterproofness and air permeability, and prevents deformation of the liquid bottle by pressurization from the outside such as a flexible liquid bottle made of resin, Or it can use suitably as a liquid bottle etc. which prevent the raise of an internal pressure also by heat processing.

  Example 1 A filter member 1 of the present invention was produced as follows.

 Spherical alumina powder is classified to have an average crystal grain size of 0.03 mm, and then a sintering aid composed of silica, calcia, and magnesia with an alumina weight ratio of 10% is mixed, granulated after adding a binder. A filter member 1 of the present invention was produced by forming a disk-shaped molded body having a diameter of 10 mm by press molding and firing to form a porous ceramic 2.

  Regarding the filter member 1 obtained above, the average crystal grain size of the porous ceramic 2 constituting the filter member 1, the average pore diameter of the pores 3 of the porous ceramic 2, and the gas-liquid separation action of the filter member 1 were verified. . Note that water was used for the following liquid 4.

 First, the liquid 4 having half the thickness of the filter member 1 was put into a container, and the filter member 1 was put therein and impregnated until the liquid 4 came out on the upper surface of the filter member 1 by capillary action. Next, as shown in FIG. 4, the filter member 1 impregnated with the liquid 4 is attached with an O-ring 17 on the outer peripheral edge of the filter member 1, and the O-ring 17 is further attached from the outer peripheral side with a magnetic holding jig 18. Was pinched. Thereafter, the gas 5 is introduced from the one surface 1a side of the filter member 1, the pressure for introducing the gas 5 is increased to 0 to 10 kPa, and the change of the pressure is changed to a Manostar gauge 19 (Chiyoda Measurement Co., Ltd.). Measured with W070). As described above, when the pressure applied to the gas 5 is increased, ventilation of the gas 5 is started from the other surface 1b of the filter member 1 at a certain pressure value. Since the pressure that has been increased and decreased at the start of the gas ventilation is decreased, the maximum pressure value before the pressure is decreased is defined as the permeation pressure of the gas 5. The generation of the permeation pressure means that a differential pressure is generated between the one surface 1a and the other surface 1b.

 If the permeation pressure of the gas 5 is high, it becomes difficult for the filter member 1 to vent the gas 5. On the other hand, if the permeation pressure of the gas is low, the filter member 1 tends to vent the gas. Since the capillary force with which the member 1 holds the liquid 4 in the pores 3 is reduced, the possibility that the liquid 4 leaks from the other surface 1b of the filter member 1 is increased.

 Here, each of the porous ceramics 2 prepared with an average crystal grain size of the alumina powder of 0.008 mm, 0.02 mm, 0.03 mm, 0.15 mm, 0.28 mm, 1.0 mm, and 1.3 mm, respectively. Sample numbers 1, 2, 3, 4, 5, 6, and 7 were used. Moreover, the average pore diameter which the porous ceramic of the filter member of the sample numbers 1-7 has was measured by the mercury intrusion method.

 In the evaluation of the permeation pressure, when the filter member 1 is used as a lid of a liquid bottle, a value less than 3 kPa, which is a value that increases the possibility that the liquid 4 leaks from the filter member 1 to the outside, is evaluated as Δ. The value exceeding 6 kPa was similarly evaluated as Δ because the gas ventilation efficiency was lowered.

On the other hand, from the powder mixing to the press molding under the same conditions as the porous ceramic constituting the filter members of sample numbers 1 to 7, a square plate-shaped molded body having a long side of 4 mm, a short side of 3 mm, and a thickness of 50 mm by the press molding. Was molded and fired to prepare a square plate-like porous ceramic, and the strength was calculated by measuring the bending strength by three-point bending. Table 1 shows the results.

 As can be seen from Table 1, the average crystal grain size of the porous ceramic constituting the filter member of sample number 1 was less than 0.02 mm, and the average pore diameter was less than 5 μm, so the strength of the filter member was improved. However, since the filter member has a dense structure, the gas permeation through the gas pores 3 is inhibited, and the gas permeation pressure is increased.

 Further, the average crystal grain size of the porous ceramic constituting the filter member of Sample No. 7 is 1 mm or more, and the average pore diameter exceeds 200 μm, so that the strength of the filter member deteriorates due to the increase of the average pore diameter. The force with which the pores 3 hold the liquid 4 was weakened, and the permeation pressure was reduced.

 On the other hand, since the average crystal grain size of the porous ceramic constituting the filter members of sample numbers 2 to 6 was 0.02 to 1 mm and the average pore size was 5 to 200 μm, the gas permeability was secured. The permeation pressure can maintain the capillary force that can hold the liquid in the pores of the porous ceramic, and the filter member can efficiently separate the gas and liquid.

It is sectional drawing which is an example of the filter member of this invention. It is a crystal schematic diagram of the filter member of the present invention. It is sectional drawing which is an example of the liquid bottle of this invention. It is sectional drawing of the apparatus which measures the gas permeability of a filter member. It is a schematic sectional drawing of the conventional liquid bottle. It is a schematic perspective view of the conventional liquid bottle. It is a schematic sectional drawing of the conventional plastic film | membrane.

Explanation of symbols

1: Filter member 1a: One surface 1b: The other surface 2: Porous ceramic 2a: Ceramic particles 3: Pore 4: Liquid 5: Gas 6: Liquid affinity agent 11: Liquid bottle 12: Support 13: Vent 14 : Space 15: Discharge port 16: Supply port 17: O-ring 18: Magnetic holding jig 19: Manostar gauge

Claims (3)

Consisting of at least one of alumina, mullite, zirconia, forsterite, silica, cordierite, and titania, the average pore diameter is 5 to 200 μm and the average crystal grain size is 0.02 to 1 mm, existing on one side The pore diameter of the porous ceramic is larger than the pore diameter of the pores existing on the other surface, and the liquid entering from the pores on the one surface of the porous ceramic is configured to be retained inside, and A filter member characterized in that a gas entering from pores on one surface is vented from the other surface. One chamber accommodating a liquid, can be supplied and discharged, the other chamber will be provided with outside air breathable vent filter member according to said one chamber and the chamber of the other to claim 1 A liquid bottle characterized by being separated by The liquid bottle according to claim 2 , wherein the filter member is held by a support provided in a chamber of the liquid bottle.

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