JPS59196712A - Thermoplastic resin filter membrane and preparation thereof - Google Patents

Abstract

PURPOSE:To prevent the lowering in filtering preciseness and efficiency, by bringing the peripheral part and/or the center part of a thermoplastic resin sheet having an open-cell microporous structure to a non-porous structure. CONSTITUTION:A filter membrane is obtained by integrally forming a filter part comprising an open-cell microporous material, the support part of the filter membrane comprising a non-porous material, a boundary part for dividing the filter part and a reinforced part for preventing the slackening of the filter membrane and diversified in functions. The molding of the membrane is performed according to a so called sintering molding system. After a cavity part is uniformly filled with granular resin, sintering molding is performed by a press molding frames held under a heated state. The parts of the press molding frames 25, 26 form the non-porous parts and the parts of the frames 23, 24 form the open-cell microporous parts. The numerals 27, 28 show heat insulating materials. The particle size of the resin is pref. adjusted to 0.01-5mm..

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter group made of thermoplastic resin and a method for manufacturing the same.

Plastics with pores, imitating the series of interconnected micropores, allow the flow of a single flow such as liquid or gas, and sheet-like or film-like plastics allow the flow of fluids such as liquids and gases. 7 Hakumukai Jp spider and L empty are used. As a permeable membrane, it is made of materials such as polyethylene thread, polypropylene, etc.
Hydrocarbon-based polystyrene thread, polyvinyl chloride thread,
Polar vinyl threads such as polyvinyritine chloride threads, other polyamide threads, or thermoplastic resins such as cellulose threads such as cellulose acetate and cellulose nitrate are incorporated.

In a continuous microporous thermoplastic resin sheet or d film (hereinafter, to simplify the observation, the sheet will be used as a representative), the continuous micropores are short-circuited and communicated between the front and back surfaces of the sheet. Since each micropore is directly connected to the surrounding micropores, there is a passageway in the surface direction of the sheet, that is, there is also a passageway in the direction toward the periphery of the sheet.
When passing a sheet between the upper and lower frames,
The fluid to be treated also flows toward the periphery of the sheet, which has the drawback of reducing the accuracy and efficiency of filtration. As a countermeasure for this drawback, a continuous microporous material with a size corresponding to the size of the frame that holds the sheet is placed around the periphery of the continuous microporous material sheet with a size corresponding to the area through which the fluid to be treated passes. There is a known method of forming a filtration membrane by bonding non-porous plastic sheets (ordinary film-formed sheets) with an adhesive or heat-sealing them.

However, there is a problem in the strength of the joint between the continuous microporous sheet and the non-porous sheet. There is a problem that separation occurs at the above joint. As other measures, the sheet strength and
A coating film is applied to prevent fluid from flowing out to the end of the filtration membrane, and the four parts are tightly fitted to the frame that holds the filtration membrane, or the frame is welded to the frame to prevent elution. However, these methods have problems such as the solubility resistance of the coated film, the adhesion strength with the filtration membrane, or the partial retention of the fluid to be treated. There is an unusual problem.

The object of the present invention is to provide a thermoplastic resin filtration membrane that eliminates the above-mentioned drawbacks and problems, and to provide an industrially advantageous method for manufacturing such a filtration membrane.

The filtration membrane of the present invention is formed integrally with a continuous microporous thermoplastic resin sheet, and its peripheral portion and/or central portion are non-porous. Accordingly, the portion connecting the peripheral portion and the central portion is integrally formed as a band-shaped non-porous material.

As the material of the P i14 film of the present invention, as mentioned above,
Any thermoplastic resin conventionally used for filtration membranes can be used to create a continuous microporous material, and the continuous microporous portion of the filtration membrane has microscopic air bubbles in the sheet that communicate in the vertical, horizontal, and horizontal directions. Up,
It is uniformly dispersed and has a filtration function by passing the P-processing fluid on the front and back sides of the sheet. Size of micropores in filtration membrane, thickness of sheet 1-ttF! It is not limited to j, but may be within the same range as conventionally used plastic filtration membranes, and is selected depending on the filtration accuracy, the size of the filter, etc.

The non-porous body part of the filtration membrane of the present invention has no continuous pores, or the peripheral end holes of the continuous microporous body part are sealed, and the through holes penetrate the front and back of the sheet (including those that penetrate through bends). ) and has a non-porous, fused and fixed form bordered by the region ) and does not have the ability to pass through V5.

Furthermore, in the filtration membrane of the present invention, the continuous microporous material portion and the non-porous material portion are integrally formed because these two portions were originally molded into a membrane as one body. This means that the continuous microporous material part and the non-porous material part are prepared separately and both are bonded with an adhesive liquid or heat-fused, or the peripheral part of a continuous microporous material sheet, etc. It does not include those in which a non-porous body portion is formed by forming a coating film by applying a coating material.

In the filtration membrane of the present invention, the non-porous body portion is located at (a) the periphery of the filtration membrane, (b) the center of the filtration membrane, (c) the periphery and center of the spastic membrane, or ) to (c), it is formed in a substantially radial band-shaped connecting portion connecting the peripheral portion and the center portion of the filtration membrane. And the position of these non-porous body parts,
The shape and thickness of the paralysis corresponds to the position where opening is required.
It is provided in advance to prevent the flow of the processing fluid, and can be selected as appropriate for the purpose of reinforcing the strength of the IP'3 membrane, partially adjusting the amount of filtration, or partially outflowing in a different direction.

Next, the filtration membrane of the present invention will be illustrated with reference to FIGS. 1 and 2. 7th
The figure is a schematic plan view of an example of the filtration membrane of the present invention, FIG. 2 is a schematic vertical cross-sectional front view of the filtration membrane shown in FIG. ~
FIG. 2 is a schematic plan view of a filter membrane according to another example of the present invention. In the figure, / is a non-porous part of the filtration membrane, and 2 is also a continuous microporous part.

The circular filter membrane shown in FIG. 1 has a non-porous peripheral edge and is installed perpendicularly to the tubular passage of the P filter. Then, the non-porous body part is clamped and fixed to the filter membrane support of the filter, and the fluid to be flooded passes through the continuous microporous body part, and the fluid does not flow out from the edge in the thickness direction of the filter membrane. blocked. Moreover, since the continuous microporous body part and the non-porous body part are integrated, the image part will not separate at the boundary even if the filtration pressure becomes high.

The membrane shown in Fig. 3 is a rectangular filtration membrane, and the peripheral part is a non-porous body part, but a part of it, ie, the part indicated by 20, is a continuous microporous electric body part, and The central portion denoted by // and the portion denoted by 7.2 connecting this central portion // and the non-porous body portion at the periphery are non-porous bodies. The filtration membrane shown in Fig. 3 has a partially different direction outflow function (
2θ), a function to adjust the filtration rate (by //), and a reinforcing function to prevent the filtration membrane from falling off, which may occur due to the installation of the non-porous material in // (by /2). It is. The continuous microporous body portion indicated by , 20 is
A part of the filter cylinder (not shown) that holds this filter membrane is
A part extraction hole is provided, and the part indicated by 10 is located in the part where the extraction hole is installed, and the filtration membrane is fixed, and the fluid to be filtered flows out from this part 20.

This allows sample collection.

The devices shown in FIGS. G to 7 are used in special cases. In other words, a simple P-hen is the most typical first
The shape shown in the figure is used, and is useful, for example, when liquids from a plurality of liquids are individually filtered and mixed. That is, filtration membranes are installed in multiple stages in a cylindrical filtration tube, with the non-porous membranes having different positions, sizes, and shapes, and branch pipes are installed in the filtration tube. The seven filtration membranes are divided so that two separate liquids are filtered, and the filtration area is adjusted to control the amount of burying of multiple processing liquids per unit time. The filtration area was changed to increase the filtration pressure. In this way, it is suitably used when a plurality of types of liquids are subjected to P overtreatment using seven sets of filter cylinders.

In the one shown in FIG. Z, a concentric ring-shaped non-porous body part /3 is provided in addition to the peripheral part, and is divided into one section indicated by a P-recess partition /j.

If the upper and lower parts of the non-porous material part /3 are held together with pipes at medium heat, the %2 glaze liquid will be treated with separate VcP, and depending on the amount of each liquid processed per unit time, / and / The filtration area of the portion j can be distributed.

Next, in the one shown in FIG. J, a non-porous body portion /6 is provided at the center of the peripheral portion. When installing this /6, if the size of the filtration membrane is very large or if the filtration tube is extremely thick, use a support that holds the center part of the membrane.
The membrane can be stably supported by holding the lower surface. As mentioned above, when filtration membranes are installed in multiple stages to process 1qa of filtration, and the filtration amount is adjusted for the seven types of liquids, the area of the central non-porous body portion 76 must be Adjust it as appropriate.In this case, it is better to use a support that holds it from above or below or not.
A non-porous η body is formed around the center part /7 and is sandwiched between supports together with the periphery of the entire membrane. If the support ff around this center part 7 is made into a tubular shape, when K filtration membranes are provided in multiple stages as described above and a liquid of multiple electrodes is processed, and no further filtration is required for the resulting filter, It is sufficient to allow the liquid to pass through this center part/2.

The one shown in Fig. 2 has no non-porous body part at the peripheral edge.
A non-porous body portion is formed in the central portion and the portion connecting the central portion and the outermost peripheral edge of the filtration membrane. As mentioned above, this product is advantageously used when filtration membranes are provided in multiple stages and multiple types of liquids are processed at the sea surface. The ubiquitous area is adjusted. The liquid passage of the filtration membrane is extremely thick.

It is used as a so-called coarser when the communication of the F liquid is easy and high filtration pressure does not occur, and the peripheral edge does not need to be tightened with strong pressure.

In this way, the filtration membranes shown in Figures 9 to 7 (including the one shown in Figure 3) are installed in a multi-stage Kf filter by appropriately combining straw and straw, and a branch pipe, that is, a bypass, is installed in the filter tube. Provide multiple types of liquids to be treated (viscosity of these liquid phases, type and size of solids contained).

Depending on the content, the difficulty of P-passing is different, and the number of v55 times is 7 times, or 2 or 3 times, depending on the combination of liquids). Subjected to filtration.

Offshore filtration can be carried out using a device consisting of a small-scale filter cylinder as a whole.

As is clear from the above, the filtration membrane of the present invention has a continuous microporous body, a supporting part of the filtration membrane consisting of a continuous microporous body, a support part made of a non-porous body, and a boundary for dividing the outer part. It is integrally formed from the same sheet, including the reinforcing part that prevents the membrane from sagging, and the function as a filtration membrane is diversified, which has been a problem in the past. The purpose of this project is to provide a highly unnecessary filtration membrane by studying the difficulties in regulating the flow rate, filtration accuracy, and strength of thermoplastic resin filtration membranes.

Next, an example of manufacturing the filtration membrane of the present invention will be described.

No.? The figure shows an explanatory diagram of one embodiment of its manufacture. And by -ntic, the disc-shaped P
An end layer in which one peripheral portion is made of a non-porous material is manufactured.

In the figure, 5.2/ and 2.2 are frame bodies of the mold, each having a circular shape, and M integrals are formed vertically. -23
and 2 are respectively cylindrical suppression molds that can be moved up and down, and are each equipped with heating means that can raise the temperature as desired. -! ! and 2g are the same ring-shaped pressing molds of the vertically movable portion, which are also equipped with heating means capable of raising the temperature to a desired temperature. , 22 and 2/ are cylindrical heat insulating materials, and the suppression formwork-23
and between 2 and 2, and pressing formwork, 24t and l! 6 and provides insulation between the two. The insulation material may be made of materials commonly used as insulation materials, such as asbestos, Teflon, and ceramics.

Next, the manufacturing method of the filtration membrane will be explained, and the membrane is formed by a so-called sintering method.

First, the suppression formwork 2 above the horizontal position indicated by arrow A in the figure
I'll leave it alone. Although it is more convenient to leave the heat insulator 27 in the position shown, the heat insulator 22 may be removed. Number 1 shows the state after the molding is completed. Initially, the suppression form 26 is lowered to the position indicated by the dotted line B.

Next, particulate thermoplastic resin is loaded into the part indicated by C (which will become the cavity). At a certain point on the suppression formwork 2B, resin particles are loaded from the line shown by B to the part shown by the line.

The resin to be loaded is selected from the above-mentioned lachrymal membranes and materials, but one with a melt index of 0.7 or more is preferred. The thick awn of the resin grains has an average particle size of θ, θ/~! Something within the fighting range is good. Grain shape/l'i Although not particularly limited, it is desirable that the surface condition is uneven, due to the relative force that facilitates the generation of pores in the continuous microporous body cylinder S. More specifically, the average particle size is r, its b is the diameter σ)
Sphere σ) narrow area, i.e. when Zπr2 is day, actual σ]
It is more preferable that S1/B is 2 or more when the grain/narrow area is S'.

After uniformly filling the cavity portion with such granular resin as described above, the pressing forms 23 and 2J', which are in an elevated temperature state, are lowered, and at the same time, the suppressing forms 2≦ are raised, and sintering is performed. perform the form. The part pressed by the suppression frames S and 26 is the part that becomes a non-porous body of the filtration membrane of the present invention, and the part pressed between the suppression frames 23 and 2Z is the part of the v5 filtration membrane of the present invention. This is the part that becomes the continuous microporous negative body.

To form a continuous microporous body, from thermoplastic resin particles,
Sintering conditions (temperature, pressure,
In order to form a non-porous η body, conditions are used such that the particles are completely fused and substantially leave a strong, integral bond, or pore. That is, in the former condition, at least one of the conditions of temperature, pressure, and time is made more severe, i.e., a higher temperature in the case of temperature, a longer time in the case of time, and a higher pressure in the case of pressure. do it. Examples of ways to achieve this include the following:

(a) Heating the part corresponding to the part where a continuous microporous body is to be formed (hereinafter referred to as the porous part) is heated to the part corresponding to the part where the non-porous body is to be formed (hereinafter referred to as the non-porous part). Porous portions and non-porous portions are formed at a temperature lower than the heating temperature.

(b) The heating of the parts corresponding to the porous parts and the non-porous parts is set to a constant constant temperature, the pressing time of the parts corresponding to the porous parts is made shorter than the pressing time of the parts corresponding to the non-porous parts, and the cooling is done. do.

(c) Heating of the porous and non-porous portions: Pressing is performed as the same process, and then, at the same time as cooling of the porous portion is started, the non-porous portion is heated to an elevated temperature to form the non-porous portion.

b) The heating temperature and heating time for the porous and non-porous areas are made equal, but the pressing force on the former is made lower than the pressing force on the latter.

By using the above method, the porous and non-porous parts are shaped. For substances with clear melting points such as tyrene and polypropylene, the melting point is used as the standard, and for substances with unclear melting points such as polyvinyl chloride, the gelation temperature is used as the standard. -io'
) It is best to choose from the range of +30°C. The temperature at which the non-porous portion is formed is preferably selected from a range higher than the temperature for the porous portion, that is, from −S° C. to 10’10° C.

If the temperature at which the porous portions are formed is too lower than the above range, surface fusion of the resin particles will be difficult to occur, and the strength at the boundary between the porous portions and the non-porous portions will be weakened. On the other hand, if the temperature is too high (in the above range), unevenness of the fused portion may occur in the porous portion, a non-porous portion may be formed on the surface in contact with the suppression mold, and the porosity distribution may become non-uniform.

Furthermore, if the temperature at which the non-porous portions are formed is too low than the above range, the non-porous portions may not be formed or porous portions may be partially generated in the thickness direction of the filtration membrane. On the other hand, increasing the thickness higher than the above range is not unnecessary and weakens the strength of the boundary with the porous portion.

Heating of the resin particles in the above-mentioned poly 1L portion and non-porous portion is carried out by incorporating heating wires into the suppression molds 23 to 2B, or by providing a path in the mold to allow the heating medium to pass through.

The pressure of heating suppression by the pressure conduit frame is ~70 to 9/c
From the range of d (gauge pressure), the time should be selected from the range of 7 to 70 minutes.The conditions for these temperature, pressure, and time depend on the type of resin, particle size, and thickness of the resulting product. , is selected depending on the pore density of the porous portion, etc.

As is clear from Fig. This is to make it more pleasant to the tongue. The mutual difference σ] between the resin particles is determined by the difference between the non-porous part and the porous part
It is better to fill the resin particles in a larger amount within the range of 10-g θ/trillion σ per unit area.

In this way, it is possible to increase the amount of resin particles packed into the non-porous area and ultimately obtain a material with a thickness of 1"o, i'*i degrees. The figure 8I-・ shows the state at this time. K H-11 hole shape.

In addition, the heat insulating material 27 has a non-porous portion and a porous portion 1! This is necessary when the processing temperature is different in the molding conditions, and the thickness of this material is usually preferably j'ynm or less. ! If the heat is exceeded, the cracked part becomes a non-heated part, which may have a negative effect on the product. Further, when the heating temperature conditions for the porous portion and the non-porous portion are to be substantially the same, the installation of the heat insulating material 27 may be omitted.

Furthermore, in the apparatus shown in Figures 1 and 2, the press formwork body may be installed in a fixed state. As shown in Figures 2 to 7, K, which manufactures non-porous parts with various shapes, uses a suppression wall frame that follows this shape, and the gap between the suppression mold and the suppression mold for forming the porous part is used. It is sufficient to provide insulation material.

As described above, it is possible to manufacture a filtration membrane in which the non-porous portion and the porous portion are integrally formed and the strength does not decrease at the boundary between the two portions.

Next, we will discuss an example of manufacturing a filtration membrane using the apparatus shown in Figs.

Example/ In this example, finely granulated polypropylene (melt index 3.θ, melting point approximately 72θ℃, average particle size θ, J'FIm pulverized product) was used, and the following (
Filtration membranes having the structure shown in FIG. 1 were manufactured under three conditions (a), (b), and (c), respectively.

Suppression represents the conditions of K −t kg/i and suppression time for both non-porous and porous areas.

(()T=/70°C, was set to approximately /?0°C, and after heating both for 5 minutes, they were turned off at the same time.

←) Both T and t were set at 173°C, and for T-j minutes,
After heating for t=10 minutes, the mixture was allowed to cool naturally.

(c) Both T and t are set to 775℃ L1 and actually 5
Heat for 5 minutes, t = 0℃ for 3 minutes.
The temperature was raised to 1, and allowed to cool naturally after each heating.

In any of the above methods, a filtration membrane of excellent quality that could be used in Tenkawa was obtained.

Example: In this example, fine granular low-pressure polyethylene (melt index /, s, @ point approx. / 34t'C1 average particle size θ, / head crushed product) was used, and the following three methods were used in the same manner as in Example /. A filtration membrane was manufactured by the method described in the following. T and t below have the same meaning as in Examples/.

(a) Set the temperature to T = /77℃, 1 = /g O℃, both! After heating for a minute, the mixture was allowed to cool naturally.

←) Both T and t were set to 1°C, and after heating for 70 minutes and 70 minutes, the sample was allowed to cool naturally.

(c) Temperatures T and t are both set to /'l/°C. After 3 minutes, the temperature was raised to 266'C over 3 minutes, and after each heating, the temperature was allowed to cool naturally. Note that the above (
In a), (b) and (c), the suppression force is T, and both are V
C! #/cd.

In the above cases as well, the obtained filtration membranes were of excellent quality η that could be put to practical use.

Next, four other manufacturing examples of the filtration membrane of the present invention will be explained.

In this case, first, a sheet consisting entirely of continuous microporous η bodies is prepared. An example of this method is to mix the material resin with a medium that is compatible with the resin but not mutually soluble. For example, when polyethylene is used, the pellet is homogeneously mixed with a dissolved ML-free organic medium (e.g. dioctyl phthalate, dioctyl adipate);
Form into a sheet using an extruder or other molding machine. In this way, a resin sheet) in which the shoulder medium is uniformly dispersed is obtained. When this is treated with a solvent (for example, 70) that dissolves the organic medium, the dispersed organic medium is removed and a continuous microporous sheet is obtained.

The obtained sheet is heated and pressed on both upper and lower sides using a pressing frame having a shape and size corresponding to the non-porous portion, thereby forming a non-porous portion having a desired shape and size. The heating temperature at this time is based on the melting point or gelling point of the cable trunk resin, and is from -s°C to
The temperature should be within the range of 100°C, and the pressing force and pressing time should be in accordance with the range shown in the manufacturing example.

By this method, the filtration membrane of the present invention of perfect quality was obtained.

The above-mentioned drawings showing the distance between stations and the detailed examples are related to typical illustrations to aid understanding of the present invention, and the present invention is not limited to these illustrations. Other changes and modifications may be made within the purpose of mourning.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of an example of the filtration membrane of the present invention, and FIG.
3 to 7 are schematic plan views of other examples of the present invention. The figure is a visit to Japan and does not show a manufacturing example of the EAP membrane-permeable membrane of the present invention. In the figure, / is the non-porous part of the filtration membrane, the continuous microporous part of the λK filtration membrane, ko/ and 2.2 are the frame, 23.2g1.
2j and 2o are suppression forms, and -22 and 2I are heat insulating materials. Fig. 1 System 2 Fig. 3 Fig. 4 Fig. 5 Exaltation Fig. 77- Fig. 7 Fig. 8

Claims (3)

[Claims] (1) A thermoplastic resin P membrane formed integrally with a continuous microporous thermoplastic resin sheet or film, the peripheral portion and/or the center of which is a non-porous material. (2) The benefit membrane according to claim 7, wherein the portion connecting the peripheral portion and the central portion is a band-shaped non-porous material. (3) In addition, the thermoplastic resin sheet or film layer of the microporous body, the peripheral part and/or the central part of which is integrally molded as a non-porous body? rl plastic resin J
1" method for producing a permeable membrane, the suppression formwork for heating and pressing the part to become the non-porous body and the suppression formwork for heating and pressing the part to become the continuous microporous body are separated. The thermoplastic resin powder or granules that filled the cavity were heated to the temperature, time, and pressure to sinter and form the microporous structure in the continuous microporous body forming part using the mold. For forming a continuous microporous body by sintering under the conditions and dissecting the non-porous body, at least the temperature, time and pressure conditions adopted for forming the continuous microporous body above are met. A method characterized by causing a non-porous body to change shape under one severe condition.