JP3937310B2 - Filter using foam and manufacturing method thereof - Google Patents

Description

【００５３】
(結果)
表１に示す如く、得られるフィルタの収縮率は、比較例２で体積比で７％程度だったものが、実施例１および２並びに比較例１では３％と改善され、引張強度について比較例１および比較例２が何れも０.３ＭＰａ未満であった数値が、実施例１および２においては夫々０.４２ＭＰａおよび０.４ＭＰａと何れも０.４ＭＰａ以上の数値となり、該強度向上が確認された。また抽出率については比較例１の９５％が比較例２並びに実施例１および２では、９９％と大きな向上が確認された。更に被捕集物の捕集率は、比較例１が５０％に対して比較例２並びに実施例１および２では７０％に向上し、透液液速度については、比較例１が６ｓｅｃに対して、比較例２並びに実施例１および２では３.５ｓｅｃに短縮した。
【００５４】
そして骨格崩壊片の発生数については、比較例１および２が１００個以上だったのに対して、実施例１および２では３０個以下しか計測されず、このフィルタはインク噴射式プリンタのインクストレーナとして好適に使用し得ることが確認された。
【００５５】
【発明の効果】
以上に説明した如く、本発明に係るフィルタおよびその製造方法によれば、骨格をフィブリル化物質によって強化すると共に、最終的に得られるフィルタが達成すべき圧力損失および被捕集物の大きさ等により決定される気泡径を水溶性気泡形成材に分級を施し制御することで、良好な流通性および被捕集物の捕集率等を達成し得ると共に、フィルタを形成する骨格崩壊片の発生を抑制し得るフィルタを得ることができる。また前記水溶性気泡形成材が浮島構造をとらず抽出可能な状態となるよう制御することで、得られたフィルタに不純物として残留する該水溶性気泡形成材等の量を低減することで、該発泡体の収縮を抑制すると共に、連通率および強度を向上させたフィルタを得ることができる。
【図面の簡単な説明】
【図１】本発明の好適な実施例に係るフィルタを構成する骨格の一部の内部状態を模式的に表すと共に、拡大して示す断面図である。
【図２】実施例に係るフィルタの製造方法を示す工程図である。
【図３】フィルタをなす発泡体の結晶構造的な内部構造(図３(ａ))および実際の内部構造(図３(ｂ))を示す概略図である。
【図４】実験例に係る透液液速度を測定する試験装置の概略図である。
【符号の説明】
１２ 骨格
１４ フィブリル化物質[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filter, and more specifically, is obtained by an extraction method and is preferably used for an ink strainer of an ink jet printer, and improves the strength of a skeleton formed from a thermoplastic resin, thereby improving the ink permeation pressure. A filter capable of avoiding the collapse of the skeleton due to, for example, and controlling the particle size of a bubble-forming material used when producing the filter within a predetermined range, thereby suppressing shrinkage and the like when the filter is obtained And a method for suitably manufacturing the filter.
[0002]
[Prior art]
In recent years, so-called ink jet printers that perform printing by ejecting ink droplets onto a print medium such as paper have rapidly become widespread. The ink ejecting printer is a printer that ejects a controlled amount of ink from an ejecting tube having an extremely small inner diameter as fine droplets onto a printing medium, and performs printing using the droplets.
[0003]
In order to suitably perform the above-described printing, that is, the ejection of ink from the ejection tube, the ink ejection printer is provided with a filter as an ink strainer for filtering ink to be ejected in advance. The filter is required to have a collecting function for collecting foreign substances having such a size as to clog the ejection pipe, and a low pressure loss that does not hinder the flow of fluid such as the ink for suitable ink supply. The
[0004]
Both the collection function and the pressure loss basically depend on the degree of opening (hereinafter referred to as the effective filter diameter) such as the ratio and size of the opening of the filter. When this filter effective diameter is small, the trapping function is good, but there is a problem that the pressure loss is large. On the contrary, when the filter effective diameter is large, the pressure loss is small while the trapping function is large. In any case, the function as a filter cannot be fully achieved.
[0005]
The pressure loss is a physical property value that is greatly affected by the effective diameter of the filter, but is also greatly affected by the internal structure of the filter in addition to the effective diameter of the filter. Specifically, if the internal structure of the filter is in a suitable communication state, the pressure loss can be set small even if the filter effective diameter is small.
[0006]
That is, when considering the use of the filter, it is necessary to suitably control the filter effective diameter and the internal structure. In consideration of these points, it is possible to manufacture a filter using a substance and a method having a structure in which the filter effective diameter can be arbitrarily controlled and the physical properties other than the filter effective diameter do not increase the pressure loss. desirable.
[0007]
One example of such a substance is a foam having bubbles in a so-called three-dimensional communication state. In this case, the diameter of the bubbles formed inside the foam is the effective filter diameter. In general, as a method for producing the foam, a foaming material is mixed in the main material, and bubbles are formed by a gas such as nitrogen generated from the foaming material, or a bubble forming material is mixed in the main material in advance. An extraction method is known in which, after being dispersed, the bubble forming material is removed to form bubbles.
[0008]
In the case of the foaming method, there is an advantage that various main materials can be used. On the other hand, it is difficult to control the generated bubble diameter to be uniform, and it is difficult to form a bubble having a small diameter of several tens of μm. On the other hand, in the case of the extraction method, since the bubble diameter to be formed depends on the type of bubble forming material used, there is an advantage that the above-described uniformity and size can be arbitrarily controlled.
[0009]
[Problems to be solved by the invention]
However, when obtaining a foam by the above extraction method, it is important to obtain a degree of mixing and ease of extraction of the bubble forming material after mixing, that is, a three-dimensional open cell structure, in general for the bubble forming material to be mixed. Therefore, attention was not paid to the size distribution of the bubble forming material.
[0010]
In the extraction method, if the size of the bubble forming material to be used is not within a certain range, it is considered that extraction cannot be performed. It is conceivable that the material remains without being sufficiently extracted and removed from the main material forming the foam, resulting in a great influence on the formation of the skeleton and the like. Specifically, there is a problem in that a homogeneous skeleton is not formed and the strength is lowered, which affects the physical properties of the foam from which the remaining foam-forming material is obtained, the open cell ratio is reduced, and the shrinkage ratio is increased. Is pointed out.
[0011]
Furthermore, even when sufficient trapping efficiency and a small pressure loss are achieved by using the bubble forming material whose size is controlled as described above, the filter is controlled by the permeation pressure of the ink passing through the filter. It is conceivable that the skeleton constituting the structure collapses. As a result, fine trapped matter in the ink is collected by the filter, while a skeleton collapsed piece caused by the permeation of the ink may cause clogging of the ejection pipe.
[0012]
The strength of the skeleton is improved by reducing the particle size of the above-mentioned bubble forming material, but is obtained by an extraction method and can achieve sufficient collection efficiency and small pressure loss. When the strength of the filter having a structure is excessively improved, that is, when the bubble forming material particle size is set to be excessively small, the trapping efficiency is improved while the pressure loss is increased. Due to the decrease in flexibility accompanying the increase in hardness, the attachment to the printer is also deteriorated.
[0013]
Further, a method of reinforcing the skeleton by adding various fillers to the main material forming the skeleton can be considered, but the following points are pointed out.
(1) When the filler is a metal, ionization of the metal may cause an adverse effect such as discoloration on the ink that passes through the filter.
(2) When the filler is an inorganic or organic material other than a metal, it is not necessary to consider the adverse effects due to the above-mentioned ionization, but in order to prevent partial collapse of the skeleton, the thickness should be as thin as possible, Such ultrafine fillers are expensive and difficult to mix uniformly with the main material.
[0014]
Specifically, the filter bubble diameter for ink filtration is considered to be preferably not larger than 50 μm. In this case, the thickness of the skeleton forming the filter is generally 30 μm or less. As a filler capable of sufficiently reinforcing such a skeleton, a filler of several μm, preferably a submicron unit is required. When the filler is too thick, the filler acts as a mere foreign substance in the skeleton to be reinforced, and conversely becomes the starting point of the skeleton collapse, reducing the strength.
[0015]
OBJECT OF THE INVENTION
The present invention has been proposed in order to suitably solve the above-mentioned problem that is manifested when a filter is obtained from a foam, and is used to produce a filter using a foam obtained by an extraction method. In The most The thermoplastic resin that forms the skeleton that forms the internal structure of the filter, which is the final product, is mixed with a fibrillated substance that is fiberized inside the skeleton to achieve an increase in the strength of the skeleton, and the formation of bubbles to be used. Material By determining the particle size based on the size of the collected material that can be achieved by the final filter, it is possible to prevent sufficient collection efficiency, small pressure loss and generation of collapsing fragments from the skeleton. It is an object to provide a filter to be obtained and a method for producing the filter. The bubble formation Material A filter capable of facilitating extraction and removal of the bubble forming material by setting the particle size range within a predetermined range, reducing the amount of impurities and shrinkage when obtaining the filter, and improving the strength, and the filter It is an object of the present invention to provide a manufacturing method.
[0016]
[Means for Solving the Problems]
In order to overcome the above-mentioned problems and achieve the intended purpose, a filter according to the present invention comprises at least one thermoplastic resin, and is thermally stable at the heat melting temperature of the thermoplastic resin, and is self-shaped. A water-soluble foam forming material capable of maintaining It is a stable substance that does not thermally decompose at the temperature at which the thermoplastic resin is hot melted. From the heated mixture of a water-soluble polymer compound that acts as a lubricant and a fibrillated material that is fiberized inside the skeleton that forms the internal structure of the filter that is the final product, the water-soluble foam-forming material and the water-soluble polymer compound Is extracted and removed by water, Inside the skeleton The fibrillated substance But Fiberization Is It is characterized by.
[0017]
In order to overcome the above-mentioned problems and achieve the intended object, a method for manufacturing a filter according to another invention of the present application is to premix at least one thermoplastic resin and a fibrillated material, thereby the fibrillated material. Prepare a premixed mixture of
The premix, and a water-soluble cell forming material that is thermally stable at a temperature at which the thermoplastic resin melts and can maintain its own shape; It is a stable substance that does not thermally decompose at the temperature at which the thermoplastic resin is hot melted. Mix with water-soluble polymer compound acting as a lubricant under heating condition,
After molding the resulting mixture into a predetermined shape,
The water-soluble bubble forming material and the water-soluble polymer compound are extracted and removed from the molded body with water to form a three-dimensional open cell structure, and the fibrillated substance is made into a fiber within the skeleton forming the three-dimensional open cell structure. Turned into It is characterized by that.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, the filter according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments. When producing the foam by the extraction method, the inventor of the present application mixes a fibrillated substance (fiber orientation) by mixing and kneading into the main material forming the skeleton and forms bubbles. Bubble formation Material By controlling the particle size range, it is possible to improve the skeletal strength of the filter obtained and to efficiently collect the collected material and to suppress pressure loss as much as possible, and to form the bubbles during extraction. Communicating by improving the rate of material extraction and removal rate It has been found that a filter with improved strength can be obtained.
[0019]
As shown in FIG. 1, the filter 10 basically includes a skeleton 12 in which a fibrillated substance 14 is fibrillated in a thermoplastic resin as a main material. The skeleton 12 is formed by extracting and removing a bubble forming material and a polymer compound, which are water-soluble substances, from a molded body, which will be described later, and the fine bubbles 16 after the extraction and removal communicate in a three-dimensional manner, so-called 3 Dimensional communication bubble structure.
[0020]
Examples of the thermoplastic resin include TPE (polyester, polyether, polyether polyester, styrene, polyamide, etc.), olefin resin (PE (LD-PE, HD-PE, LL-PE, α-olefinated PE). ), PP and TPO), TPU, polyamide, polyimide, polyacetal or any other resin that melts when heated. The use of a plurality of thermoplastic resins having similar melting points can be used in consideration of physical properties and the like.
[0021]
In particular, a material having some compatibility with the fibrillated material 14 described later ([0025]) is preferably used. When the fibrillated material 14 is polytetrafluoroethylene, polypropylene or polyethylene is preferable. . A solubility parameter is generally used as an indicator of the compatibility, and the difference in solubility parameter between the thermoplastic resin and the fibrillated material 14 is 0.5 or more, preferably 0.5 to 1. It is desirable to be in range.
[0022]
If the difference in solubility parameter is less than 0.5, the thermoplastic resin and fibrillated material 14 are compatible and the fibrillated material 14 cannot maintain its shape, resulting in the fibrillation. Structural strengthening by the fibrillation of the substance 14, that is, strength improvement will not be made. When the difference in solubility parameter is in the range of 0.5 to 1, the thermoplastic resin and the fibrillated material 14 are only partially compatible with each other, and structural strengthening by the fibrillated material 14 is not caused. The thermoplastic resin and the fibrillated material 14 are in a so-called familiar state without being hindered, and thus strength deterioration due to structural separation caused by external force is not caused.
[0023]
When the difference in solubility parameter exceeds 1, the thermoplastic resin and the fibrillated material 14 are hardly compatible with each other. Therefore, the above-mentioned problem due to the integration of the fibrillated material 14 with the thermoplastic resin is I don't get up. However, when the difference in solubility parameter is too large, it should be noted that strength degradation becomes a problem due to structural separation between the thermoplastic resin and the fibrillated material 14.
[0024]
The solubility parameter (δ value) used here can be calculated from the molecular structure and density of the compound based on the molecular attraction constant of the compound substituent (“Adhesion Chemistry and Actuality” by Hyun Keiun) 21-26 pages, published in 1962. The molecular attractive constant is described in Journal of Applied Chemistry (Vol. 3, pages 71 to 80, issued in 1953) by PS Small.
[0025]
As the fibrillated material 14, a material that causes fiber orientation, that is, so-called fibrillation, is used by breaking the fiber in the fiber axis direction, such as polytetrafluoroethylene. Moreover, in order for this substance 14 to fibrillate suitably, it is necessary to apply sufficient shearing force, etc. In the present invention, it is achieved by sufficient kneading and mixing with the thermoplastic resin whose strength should be improved. Is done. When the kneading / mixing of the thermoplastic resin and the fibrillated material 14 is sufficient, the kneading / mixing force and the viscosity for performing sufficient physical mixing utilizing the kneading / mixing force are sufficient. It is empirically found that the viscosity is preferably 10,000 Pa · s or more. When the viscosity is less than 10,000 Pa · s, only the thermoplastic resin, which is the main material, is not easily stirred, and sufficient shearing force is not applied to the fibrillated substance 14 and fibrillation is not performed. End up.
[0026]
For example, in the case of a filter used for an ink strainer of an ink jet printer, the amount of the fibrillated substance 14 added is 0.1 to 100 parts by weight of the thermoplastic resin that is the main material forming the skeleton 12. The range of 10 parts by weight is preferable, and the tensile strength of the filter 10 finally obtained by addition of this range is 0.4 MPa or more for suppressing the generation of disintegrated pieces of the filter skeleton 12 due to ink permeation. (See Experimental Example [0048]). When the amount of the fibrillated substance 14 added is less than 0.1 part by weight, the fibrillation is not sufficient and the strength of the entire skeleton 12 cannot be sufficiently improved. On the other hand, when the added amount of the fibrillated substance 14 exceeds 10 parts by weight, the flexibility is lowered due to the increase in hardness accompanying the improvement in the strength of the filter 10 itself, and as a result, the attachment property to a housing such as a printer is deteriorated. Or excessive excess of the fibrillated substance 14 is present outside the skeleton 12, thereby causing a problem of increased pressure loss.
[0027]
Even if the ink jet printer is used other than the ink strainer, the fibrillated material 14 is mixed and sufficiently kneaded to achieve the tensile strength that the filter should achieve. A filter corresponding to a high strength can be manufactured.
[0028]
As described above ([0025]), the fibrillation substance 14 progresses in fibrillation in proportion to the magnitude and time of the force applied to kneading or the like, that is, the degree of kneading / mixing. It has a positive effect on improving the strength of the skeleton. Accordingly, the strength can be improved if the added amount is at least sufficient for mixing. Further, since the collapse of the skeleton due to the fluid osmotic pressure of an actual ink or the like is considered to be caused by the filter 10 being pulled in the flow direction of the fluid, the tensile strength was used as an index for evaluating the skeleton collapse.
[0029]
As the water-soluble foam forming material, any substance that is water-soluble and thermally stable at a temperature at which the thermoplastic resin is melted and can maintain its shape can be used. For example, as an inorganic substance, NaCl, KCl, CaCl ₂ , NH _Four Cl, NaNO _Three , NaNO ₂ Etc. Examples of organic substances include TME (trimethylolethane), trimethylolpropane, trimethylolbutane, sucrose, soluble starch, sorbitol, glycine, or sodium salt of each organic acid (malic acid, citric acid, glutamic acid, or succinic acid). . In use, a large number of granular materials capable of predetermined classification are used.
[0030]
Examples of the water-soluble polymer compound include polyethylene glycol derivatives such as polyethylene glycol, polyethylene glycol diacrylate, polyethylene glycol dioleate, and polyethylene glycol diacetate, as well as heat at a temperature at which the thermoplastic resin is melted by heat. Cheap material that does not decompose It acts as a lubricant and is a substance that becomes indefinite and fluidized under heating and mixing to obtain a heated mixture. Any compound can be used as long as it is a compound that functions to lower the viscosity of the thermoplastic resin at the same time. In particular, polyethylene glycol can be preferably used because of its high melt flow and high water solubility. In addition, when an organic material is selected as the bubble forming material, the action of promoting the extraction / removal of the bubble forming material has also been confirmed. Further, when the molding is performed by an extrusion molding method, the polyethylene glycol has a molecular weight of 2,000 to 30,000, preferably 5,000 to 25,000, more preferably 15,000 to 25,000. The knowledge is obtained. In use, if necessary, the same as the bubble forming material Many A number of granules are used.
[0032]
Formation of water-soluble bubbles Material The particle size is the size of the bubbles 16 formed in the filter 10, and the size of the bubbles 16 is determined by the size of the object to be collected and the pressure loss. Specifically, the upper limit of the bubbles 16, that is, the upper limit of the particle size is determined by the size of the collected matter to be collected, and the pressure loss is the lower limit of the bubbles 16, that is, the lower limit of the particle size. Note that if this value is too small, the pressure loss becomes excessive and the filter is not suitable for use as a filter.
[0033]
The mixing ratio of the thermoplastic resin, the water-soluble bubble forming material, and the water-soluble polymer compound (water-soluble substance) is preferably in the range of 10:90 to 40:60 by volume percentage. When the ratio of the thermoplastic resin is less than 10%, the filter cannot maintain its shape during the extraction / removal of the water-soluble substance and collapses. On the other hand, when the ratio of the thermoplastic resin exceeds 40%, that is, when the water-soluble substance is less than 60%, a sufficient number of bubbles are not formed, and as a result, a sufficient three-dimensional open cell structure is formed. Not formed rate The pressure loss worsens due to the decrease. In particular, the mixing ratio of the thermoplastic resin is preferably in the range of 12 to 35%.
[0034]
The mixing ratio of the water-soluble bubble forming material and the water-soluble polymer compound is set in the range of 45:55 to 95: 5 in terms of volume percentage. When the water-soluble foam forming material is less than 45%, a three-dimensionally communicated foam structure cannot be obtained. When the water-soluble foam forming material exceeds 95%, the extraction ratio of the water-soluble substance is reduced and a sufficient bubble ratio is obtained. That is, communication rate Cannot be obtained. In particular, the mixing ratio of the water-soluble foam-forming material and the water-soluble polymer compound is preferably in the range of 65:35 to 88:12 by volume percentage.
[0035]
When the mixing ratio of the thermoplastic resin, the water-soluble cell forming material, and the water-soluble polymer compound is set in the above-described range, the water-soluble cell forming material is obtained by immersing a molded body obtained by molding these mixtures in water. In addition, the water-soluble polymer compound can be easily and sufficiently extracted and removed. That is, a filter having a three-dimensional open cell structure with homogeneity and strength can be obtained by using the thermoplastic resin as a main material and collecting the collected material efficiently.
[0036]
【Production method】
In order to manufacture the filter according to the present invention, as shown in FIG. 2, first, the thermoplastic resin as the main material and the fibrils that are fiberized by kneading and mixing in the skeleton 12 formed from the thermoplastic resin. Preparation of water-soluble bubbles that form bubbles 16 while preparing a premixed mixture of the chemical substance 14 in advance Material Perform classification to obtain the required particle size and form the water-soluble bubbles. Wood The water-soluble polymer compound and the premix are mixed and kneaded using a predetermined device and mixed by heating. body Or by performing extrusion molding, injection molding, or the like, and immersing the molded body having a predetermined filter shape in water or warm water at a predetermined temperature, thereby extracting the water-soluble bubble forming material and the water-soluble polymer compound. The filter 10 is made of the skeleton 12 in which the fine bubbles have a three-dimensional open cell structure and the strength of the fibrillated substance 14 is improved by fibrillation. Depending on the case, it is possible to adopt the filter as it is without performing the extrusion molding or injection molding.
[0037]
The fibrillated substance 14 needs to be kneaded and mixed in advance with a thermoplastic resin which is a main material for forming the skeleton 12. If this premixing is not performed, the necessary four types of materials, that is, the thermoplastic resin, the fibrillated material 14, the water-soluble cell forming material, and the water-soluble polymer compound are kneaded and mixed at once. Not all are taken into the thermoplastic resin and sufficient strength improvement cannot be expected, and the same phenomenon as the above [0026], that is, the presence of the fibrillated substance 14 outside the skeleton 12 causes pressure loss. It is conceivable that a problem such as an increase in the number of times will occur.
[0038]
Formation of water-soluble bubbles Material For classification, although it depends on the particle size to be classified, it is generally classified by a sieve that sets the upper limit of the required particle size, and then the lower limit of the required particle size is set. Classification is performed to obtain a granular material having a particle size within a set range. Basically, sieving classification has a higher classification efficiency per hour than air classification, but clogging is a concern for fine particle sizes, so the upper limit of the particle size is set prior to the air classification at the lower limit of the particle size. If classification is performed with a sieve, efficient classification can be performed in a short time without clogging.
[0039]
Sufficient kneading / shearing force of a twin-screw extruder, kneader, kneader, Banbury mixer, Henschel type mixer, rotor type mixer or other kneader for mixing and kneading the thermoplastic resin and the fibrillated substance 14 Those having the following are preferably used.
[0040]
A kneading / mixing of the premix obtained by mixing and kneading the thermoplastic resin and the fibrillated substance 14, the water-soluble foam forming material and the water-soluble polymer compound is carried out by using a single-screw or twin-screw extruder, kneader. A kneader, Banbury mixer, Henschel type mixer, rotor type mixer or other kneader that can sufficiently knead and mix the premix, the water-soluble foam-forming material and the water-soluble polymer compound is preferably used.
[0041]
Note that no special apparatus is required for any of the above-mentioned kneading, and the kneading speed is not limited. The temperature at the time of kneading is appropriately set depending on the heat melting point of the thermoplastic resin used, etc., but in the present invention, the water-soluble bubble forming material and the water-soluble polymer compound are melted at the heat melting point of the thermoplastic resin. Or, since it does not sublime, it can be set at any temperature. The kneading time for mixing and kneading the thermoplastic resin, water-soluble cell forming material and water-soluble polymer compound depends on the physical properties of the various mixtures, but it is sufficient that the mixture is sufficiently mixed and kneaded. About 30 to 40 minutes is sufficient.
[0042]
As for the kneading, it is known that fibrillation of the fibrillated substance 14 is promoted by applying a sufficient time and shearing force. Thereby, sufficient strength improvement can be expected even if the fibrillated substance 14 is less than or equal to the above-mentioned addition amount.
[0043]
The mixture obtained by kneading each raw material can be physically molded into the required filter shape by extrusion, injection, press or roller, etc., but it can form an extruded or complex shape with particularly high mass productivity. Molding by injection is preferred.
[0044]
A filter formed by mixing each component into a required shape is obtained by mixing the water-soluble foam-forming material and the water-soluble polymer compound with water as a solvent for a predetermined time (for example, 12 to 24 hours, the shape and thickness of the molded body). It is extracted and removed by soaking. This immersion time is shortened compared to the uncontrolled filter because the particle size of the water-soluble foam forming material and the water-soluble polymer compound to be extracted is controlled (the reason is [0046 ]).
[0045]
The immersion at this time may be any method, but extraction / removal by immersion in water in which the entire compact is brought into contact with water is suitable. The temperature of the water used at this time is not particularly limited and may be about room temperature. For efficient removal of the water-soluble substances, warm water of 15 to 60 ° C. is used. May be.
[0046]
The extraction and removal of the water-soluble bubble forming material by the extraction is performed when the thermoplastic resin and the water-soluble bubble forming material are mixed. By making the numerical range of the particle size of the material or the like fall within the range of 0.16 × n to 6.45 × n (where n is a natural number), as shown in FIG. It is considered that the water-soluble bubble forming material or the like that cannot be extracted, that is, floating island structure, is not present in the thermoplastic resin (see FIG. 3B). Therefore, when setting the bubble diameter of the filter, it is desirable that the range of the bubble diameter be within the range of the above-mentioned numerical values, and by setting the range to such a range, the water-soluble bubble forming material Thus, efficient and quantitative extraction such as the above becomes possible.
[0047]
As an application in which the filter according to the present invention is used, for example, a foreign matter collecting filter, that is, a so-called ink strainer in an ink jet printer, which needs to collect a normal object to be collected efficiently can be cited. In addition, the fluid flowing through the filter can be any of various gases and liquids. For example, it can be used for collecting a particularly fine collection object such as a clean room filter used at room temperature. Preferably used.
[0048]
[Experimental example]
Examples of the filter according to the present invention will be shown below. This filter was obtained by mixing a premix obtained by premixing a thermoplastic resin and a fibrillated material, which will be described later, for 30 minutes, a water-soluble foam-forming material, and a water-soluble polymer compound. heating mixture body Is a test piece having a width of 100 mm, a length of 100 mm, and a thickness of 3.5 mm under the conditions of a temperature of 150 ° C. and a time of 60 seconds using a general-purpose hot press apparatus, followed by extraction treatment with water and hot air drying for 24 hours It is obtained by performing a drying process by a machine. In Examples 1 and 2, filter test pieces for testing were prepared by controlling the particle size of the water-soluble bubble forming material and the water-soluble polymer compound to 100 to 250 μm by air classification. Further, as Comparative Example 1, a fibrillated substance was not added, and as Comparative Example 2, a particle size was not controlled in the same manner as in the above Example (each component used was [0051], and the mixing ratio was Each is shown in Table 1). And about the obtained four test pieces, each physical property required for a foam using visual or various measuring instruments, the extraction rate (%) shown in Table 1, shrinkage rate (%), and tensile strength (MPa) As a physical property value corresponding to the pressure loss before collection of the collected material, the liquid permeation rate (sec / 10cc (details will be described later [0049])), the skeletal disintegration piece of the filter due to fluid permeation under a predetermined condition (10 μm) The number of occurrences (number (details will be described later in [0050], implemented in Examples and Comparative Examples 2)) and the collection rate (%) of 10 μm collected material (carbon beads) were observed and measured.
[0049]
About the said pressure loss, the liquid permeation | transmission liquid speed (sec / 10cc) was measured using the test apparatus 50 shown in FIG. The test apparatus 50 basically includes a cylindrical tube 52 having an inner diameter of 5 mm and a filter 54 processed into a cylindrical shape of φ5 × 3 mm that can be fixedly placed inside the cylindrical tube 52. 10 cc of ethanol is passed through and the time required for the passage is measured. In this case, the passage time becomes longer when the pressure loss is larger.
[0050]
As for the number of collapsing pieces, an apparatus similar to the test apparatus 50 shown in FIG. 4 is used to evaluate the ink jet printer as an ink strainer. As a filter that can be fixedly arranged inside the tube, a cylindrical shape of φ7 × 3.5 mm was used, and a grid mesh with an interval of 10 μm was disposed immediately below the filter. Then, ethanol as a total of 50 cc of fluid was permeated from above at a rate of 1 cc / sec, and after permeation, the number of disintegration pieces remaining on the mesh was measured using an optical microscope. In this case, the skeleton strength that forms the filter is weaker when more collapsed pieces are measured.
[0051]
In addition, each component, apparatus, etc. which are used by an experiment example and a comparative example are as follows.
Thermoplastic resin: General-purpose polyolefin resin
Water-soluble foam forming material: General-purpose salt
Water-soluble polymer compound: General-purpose polyethylene glycol
Fibrilized material: Product name Metablen (Mitsubishi Rayon)
·Used equipment
Kneading and mixing of thermoplastic resins and fibrillated materials
: Nida Product name Lab mixer (manufactured by Toyo Machine)
Kneading / mixing premixture of thermoplastic resin and fibrillated material with other materials
: Extruder name Labo Plast Mill (Toyo Seiki)
[0052]
[Table 1]

[0053]
(result)
As shown in Table 1, the shrinkage ratio of the filter obtained was about 7% by volume in Comparative Example 2, but improved to 3% in Examples 1 and 2 and Comparative Example 1, and the tensile strength was Comparative Example. 1 and Comparative Example 2 were both less than 0.3 MPa, but in Examples 1 and 2, 0.42 MPa and 0.4 MPa were both 0.4 MPa or more, confirming the improvement in strength. It was. As for the extraction rate, 95% of Comparative Example 1 was confirmed to be significantly improved to 99% in Comparative Example 2 and Examples 1 and 2. Furthermore, the collection rate of the collected material is improved to 70% in Comparative Example 2 and Examples 1 and 2, compared to 50% in Comparative Example 1. Transparency The liquid-liquid speed was shortened to 3.5 sec in Comparative Example 2 and Examples 1 and 2 compared to 6 sec in Comparative Example 1.
[0054]
The number of skeletal disintegration pieces was 100 or more in Comparative Examples 1 and 2, whereas only 30 or less were measured in Examples 1 and 2. This filter is an ink strainer for an ink jet printer. As a result, it was confirmed that it can be suitably used.
[0055]
【The invention's effect】
As described above, according to the filter and the manufacturing method thereof according to the present invention, the skeleton is strengthened by the fibrillated substance, the pressure loss to be achieved by the finally obtained filter, the size of the collected matter, and the like. The bubble size determined by the water-soluble bubble formation Material By performing the classification and controlling, it is possible to obtain a filter that can achieve good flowability, a collection rate of collected materials, and the like, and can suppress the generation of skeleton collapse pieces that form the filter. The water-soluble bubble formation Material By controlling so that it can be extracted without taking a floating island structure, the amount of the water-soluble foam forming material remaining as impurities in the obtained filter is reduced, and the shrinkage of the foam is suppressed. , Communication rate In addition, a filter with improved strength can be obtained.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view schematically showing an internal state of a part of a skeleton constituting a filter according to a preferred embodiment of the present invention.
FIG. 2 is a process diagram illustrating a method for manufacturing a filter according to an embodiment.
FIG. 3 is a schematic view showing a crystal structural internal structure (FIG. 3A) and an actual internal structure (FIG. 3B) of a foam constituting a filter.
FIG. 4 is a schematic view of a test apparatus for measuring a liquid permeation velocity according to an experimental example.
[Explanation of symbols]
12 skeleton
14 Fibrilized substances

Claims (5)

At least one thermoplastic resin, a water-soluble cell forming material that is thermally stable at the heat melting temperature of the thermoplastic resin and capable of maintaining a self-shape, and heat at a temperature at which the thermoplastic resin is hot melted It is a stable substance that does not decompose, and becomes water-soluble polymer compound that acts as a lubricant by becoming indefinite and flowing under heat mixing, and inside the skeleton (12) that forms the internal structure of the filter that is the final product. from the heating mixture of fibrillated material (14) for fiberizing, the water-soluble foaming material and water-soluble polymer compound have been extracted and removed by water, inside the fibrillation material of the skeleton (12) ( 14) is fiberized
A filter characterized by that. The filter according to claim 1 , wherein a tensile strength of the filter in which the fibrillated substance (14) is fiberized is set to 0.4 MPa or more. At least one thermoplastic resin and a fibrillated material (14) are premixed, thereby preparing a premixture in which the fibrillated material (14) is fiberized;
The premix, the water-soluble foam-forming material that is thermally stable at a temperature at which the thermoplastic resin is thermally melted , and capable of maintaining a self-shape, and the stable at which the thermoplastic resin is not thermally decomposed at the temperature at which the thermoplastic resin is thermally melted A water-soluble polymer compound that acts as a lubricant by mixing with a water-soluble polymer compound that is indefinite and heated under heat mixing .
After molding the resulting mixture into a predetermined shape,
The water-soluble bubble forming material and the water-soluble polymer compound are extracted and removed from the molded body with water to form a three-dimensional open cell structure, and the fibrillation is performed inside the skeleton (12) forming the three-dimensional open cell structure. A method for producing a filter, wherein the substance (14) is made into a fiber. Amount of the fibrillated material (14) is pre Kinetsu By setting the range to plastic resin 0.1% to 10% in weight percentage, claims that the tensile strength of said filter and 0.4MPa or more Item 4. A method for producing a filter according to Item 3 . Wherein as the water-soluble foam-forming material, by using a granulate having a particle size which is set to a predetermined range by classification, the improvement of communication of the filter to be removed by extraction of the water-soluble foaming material and obtained is achieved The method for manufacturing a filter according to claim 3 or 4 , wherein the filter is manufactured.

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