JP5883229B2 - Method for producing ultra-fine porous tube - Google Patents

Description

  The present invention relates to an ultrafine porous tube and a method for producing the same, and more particularly to an ultrafine porous tube capable of obtaining stable outer diameter accuracy and a method for producing the same.

  Patent Document 1 includes an inner annular portion, a plurality of rib portions extending radially at substantially equal intervals along the outer periphery of the inner annular portion, and an outer annular portion connecting the plurality of rib portions. A hollow portion is formed by the inner annular portion, the rib portion, and the outer annular portion, and the inner annular portion and the outer annular portion have a lotus root-like cross-section in a longitudinal sectional view. A perforated tube and a method for producing the same have been proposed.

JP 2009-97580 A

  However, in the manufacturing method described in Patent Document 1, it is not possible to stably manufacture an ultrafine porous tube having a mean outer diameter of 0.5 mm or less, and in particular, an ultrafine porous with a good outer diameter accuracy in the longitudinal direction. The tube was not obtained. That is, when producing an ultra-fine porous tube of less than 0.5 mm, when melt-extruded in a normal temperature atmosphere and cooled, the resin is rapidly solidified by cooling, and the outer diameter accuracy cannot be stably obtained. In addition, there is a problem that the target outer diameter cannot be reduced.

Therefore, as a result of intensive studies on a method for stably producing an ultrafine porous tube having excellent outer diameter accuracy, the present inventors have performed melt extrusion from a die having a predetermined shape vertically downward, and heating and cooling during cooling. Thus, it was learned that the stability in the longitudinal direction and the cross-sectional shape accuracy can be improved, and the present invention has been completed.
In order to solve the above problems, the present invention provides the following [1] to [9].
[1] An ultrafine porous material made of a thermoplastic resin having a substantially circular, polygonal, or elliptical cross section, an assumed outer diameter average value of 0.5 mm or less, and two or more continuous hollow portions in the longitudinal direction. An ultra-fine porous tube, characterized in that the assumed outside diameter variation rate in the longitudinal direction is 2% or less.
[2] The ultra-fine porous tube according to [1], wherein the cross section is substantially circular, the assumed outer diameter variation rate in the longitudinal direction is 2% or less, and the roundness is 90% or more.
[3] The transverse section includes a central space portion, an inner annular portion surrounding the central space portion, a plurality of rib portions extending radially from the inner annular portion, and an outer annular portion connecting between outer ends of the rib portions. The microporous tube according to [1] or [2], which has a plurality of hollow portions surrounded by the inner and outer annular portions and the rib portions.
[4] The microporous tube according to any one of [1] to [3], wherein the cross section includes a core portion filled with resin at the center and a plurality of hollow portions around the core portion.
[5] The ultrafine porous tube according to [3], wherein an optical fiber for image transmission or high-speed signal transmission, or a tensile body linear object is provided in a central space.
[6] When manufacturing the ultrafine porous tube according to the above [1] to [4], the internal pressure for forming the hollow portion is designed to obtain the ultrafine porous tube having a desired cross-sectional shape and the die corresponding portion forming the hollow portion. Using a die with a through hole for introducing adjustment air, while introducing the air for adjusting the internal pressure into the hollow part, the molten resin is extruded vertically downward from the die hole part for forming the resin part of the microporous tube. , A manufacturing method that takes over the cooling process,
The production method includes the following steps (1) to (2): A method for producing an ultrafine porous tube.
(1) A slow cooling step of pulling down the extruded product in a heated cylinder heated to a temperature below 40 ° C. or more and less than the vicinity of the melting point of the resin that forms the resin part immediately below the die,
(2) Next, at least one stage of air cooling zone near room temperature is provided, and the resin part is cooled to near room temperature by passing it through air cooling, or it is further cooled with water as needed and extruded to near room temperature. A cooling process that cools things.
[7] When manufacturing the ultrafine porous tube according to [5], the hollow portion is designed to obtain an ultrafine porous tube having a desired shape, having an introduction hole for introducing an ultrafine wire in the center. Using a die provided with a through hole for introducing the internal pressure adjusting air for forming the hollow part in the part corresponding to the die forming the inner diameter, while inserting the air for adjusting the internal pressure into the hollow part, an extra fine wire was inserted into the introducing hole. In this manufacturing method, the resin melted from the die hole portion for forming the resin portion of the microporous tube around the periphery is extruded vertically downward and is covered with the resin portion having a plurality of hollow portions,
The production method includes the following steps (1) and (2): A method for producing an ultrafine porous tube.
(1) A slow cooling step of pulling down the extruded product in a heated cylinder heated to a temperature below 40 ° C. or more and less than the vicinity of the melting point of the resin that forms the resin part immediately below the die,
(2) Next, at least one stage of air cooling zone near room temperature is provided, and the resin part is cooled to near room temperature by passing it through air cooling, or it is further cooled with water as needed and extruded to near room temperature. A cooling process that cools things.
[8] An ultrafine porous deaeration tube using the ultrafine porous tube according to [4], wherein the thermoplastic resin is a fluororesin, polyolefin resin, polyimide resin, polyamide resin, polyester resin, polystyrene resin, and vinyl chloride. It consists of one kind of thermoplastic resin selected from resins, has a core part filled with resin at the center, the assumed outer diameter average value of the outer annular part is 0.5 mm or less, and the assumed outside diameter fluctuation rate in the longitudinal direction is 2 % Ultra-fine porous deaeration tube, characterized by
[9] An ultra-fine porous medical tube using the ultra-fine porous tube according to [3], wherein an ultra-fine optical fiber made of quartz or plastic is provided in a central hollow portion, and a mean outer diameter is assumed to be 0. An ultra-fine porous medical tube, characterized in that it assumes a longitudinal outer diameter variation rate of 2% or less at 5 mm or less.

According to the present invention, it is an ultrafine porous tube having an assumed outer diameter average value of 0.5 mm or less made of a thermoplastic resin and having two or more continuous hollow portions in the longitudinal direction, and the assumed outer diameter variation rate in the longitudinal direction. Is 2% or less, and the outer diameter accuracy is good. Therefore, precise module processing is easy, and it can be used for equipment that requires lightweight and thin wall.
In the case of a circular cross section, since the roundness is high, the end processing of a module or the like is particularly easy.
Since the center can be a space or a core, the required performance such as the required porosity and tensile strength of the tube can be easily met.
Moreover, it can be set as a very fine porous tube which has functionality by inserting an optical fiber and a tensile-strength body linear object in the center space part.
The method for producing an ultrafine porous tube of the present invention can produce an ultrafine porous tube having an assumed outside diameter average value of 0.5 mm or less stably in the longitudinal direction with a low assumed outside diameter variation rate.

(A)-(F) It is sectional drawing of the ultra-fine porous tube which shows the example of the various cross-sectional shape which concerns on this invention. It is the top view which looked at the die | dye used in order to obtain the microporous tube of the cross-sectional shape of FIG. 1 (A)-(D) from the opening side. It is a conceptual diagram which shows an example of the manufacturing method of the microporous tube which concerns on this invention.

  Hereinafter, preferred embodiments of the present invention will be described. Each embodiment shown in the accompanying drawings shows an example of a typical embodiment according to the present invention, and the scope of the present invention is not interpreted narrowly.

FIG. 1 shows an embodiment of a longitudinal cross section of an ultrafine porous tube according to the present invention, and the ultrafine porous tube 1A shown in FIG. 1 (A) has two hollows surrounded by an outer annular portion 1a and a rib portion 2a. An ultrafine porous tube 1B having a portion 3a and having three hollow portions 3b shown in FIG. In addition, an ultra-fine porous tube 1C shown in FIG. 1C has six hollow portions 3c divided into six rib portions 2c between an outer annular portion 1c and an inner annular portion 4c and a central space portion 5c. doing. On the other hand, the microporous tube 1D shown in FIG. 1 (D) has a core portion 6d filled with resin at the center and six hollow portions 3d on the outer periphery thereof.
In the present invention, the size of the ultrafine porous tube and the number of hollow portions can be appropriately selected according to the purpose within the range where the effects of the present invention can be obtained.
1A to 1E show a circular cross section, it may be a substantially circular shape or a substantially polygonal shape such as a hexagon as shown in FIG. The assumed outer diameter average value is 0.5 mm or less.
The ultra fine porous tube 1 (for example, 1A to 1F) according to the present invention is to maintain better mechanical characteristics such as lateral pressure characteristics and bending characteristics, and the roundness or regular polygonality of the ultra fine porous tube structure. It is desirable that the number of the rib portions 2 be three or more. When the number of ribs is less than 3, for example, when used as an ultrafine porous tube for degassing, when the liquid is passed through the hollow portion and degassed, deformation due to the pressure difference becomes large, whereas on the other hand, Since the porosity is small, 4 to 6 is preferable. In particular, the case of six pieces (substantially hexagonal in cross section) is preferable because the terminal portion when the ultra-fine porous tube is modularized can be closely packed into the hexagonal honeycomb structure.
In the present invention, the deemed outer diameter average value means an average value of outer diameters measured by a measuring method described later.
By setting the assumed outside diameter average value to 0.5 mm or less, an ultrafine porous tube having excellent characteristics even at a practical level can be obtained.

  The outer annular portion 1 (1a to 1f), the rib portion 2 (2a to 2f), the inner annular portion 4 (4c, 4e, 4f), and the core portion 6 (6d) are integrally formed by melt extrusion molding of a thermoplastic resin. Is done.

The thermoplastic resin used in the ultrafine porous tube of the present invention is not particularly limited as long as it can be melt-extruded. For example, fluorine resin such as PFA, polyolefin resin, cyclic polyolefin (APO) resin, syndiotactic polystyrene (SPS) ) Resin, polymethylpentene (TPX) resin, polyethylene naphthalate (PEN) resin, and the like.
In particular, when used as a deaeration tube for flowing a liquid into a space and removing a gas dissolved in the liquid, a fluororesin, a polyolefin resin, a polyimide resin, a polyamide resin, a polyester resin, a polystyrene resin, and a vinyl chloride resin One kind of thermoplastic resin selected from is used.
These thermoplastic resins have gas-permeable and liquid-impermeable characteristics.

In the microporous tube according to the present invention, the assumed outside diameter variation rate (CV value) in the longitudinal direction is set to 2% or less. In the present invention, the assumed outer diameter fluctuation rate is an oscillating laser outer diameter measuring device that reciprocally rotates an angle of ± 90 ° around the central axis in 10 seconds with respect to the obtained ultrafine porous tube while continuously manufacturing. The outer diameter is measured at a measurement speed of 50 times per second for 40 seconds, and the average value of the outer diameters (number of measurements: 50) measured for 1 second is not taken as the outer diameter.
Further, continuously measure for 40 seconds, obtain the average value of the assumed outside diameter and its standard deviation, and do not look at this deemed outside diameter standard deviation and divide by the outside diameter average value (variation coefficient) in% (variation rate = CV value). It is displayed.
When the assumed outside diameter fluctuation rate exceeds 2%, it is not preferable from the viewpoint of the workability of the terminal where dimensional accuracy is required.

In the ultra fine porous tube according to the present invention, the roundness is preferably 90% or more in the case of the ultra fine porous tube having a substantially circular cross section. In the present invention, the roundness is expressed by the following formula when the longest diameter of the outer annular portion 1 is a, the shortest diameter is b, and the average outer diameter is c (c = (a + b) / 2) in FIG. This value indicates how close the microporous tube is to a perfect circle.
Roundness ratio = (1− (a−b) / c) × 100

In the present invention, as shown in FIG. 1 (E), an ultrafine porous tube provided with an optical fiber or a tensile body linear object in the central space is also provided.
Examples of the optical fiber used in the space include quartz or plastic optical fibers having an outer diameter of 250 μm or less.
Further, as the tensile body linear material, a high-strength wire material that can sufficiently withstand external force such as tensile force such as aramid fiber, stretched polyester monofilament, piano wire, etc. is desirable, and the tensile strength is 0.4 GPa or more. Are particularly preferred.

  Moreover, it does not limit about the hollow rate of the microporous tube 1, It can be set as a suitable hollow rate suitably. In the microporous tube 1 according to the present invention, it is not necessary to reduce the amount of fluid transport per unit time in the tube, and the pressure loss is increased so that it is not necessary to make the material compatible with high pressure. In addition, the occurrence of kinks or the like can be prevented. According to the present invention, an ultrafine porous tube excellent in kink and the like while having a high hollow ratio can be obtained. This hollow ratio is very fine with respect to the cross-sectional area of the ultra-fine porous tube 1 (the total of the cross-sectional areas of the outer annular portion 1, the rib portion 2, the inner annular portion 4, the optical fiber or the tensile body linear object and the hollow portion 3). The ratio of the cross-sectional area of the hollow part 3 of the porous tube 1 is said. The hollowness is preferably 30 to 60%.

  The first aspect of the method for producing an ultrafine porous tube according to the present invention is designed to obtain an ultrafine porous tube having a desired cross-sectional shape, and is used for introducing internal pressure adjusting air for forming a hollow portion into a portion corresponding to a die forming the hollow portion. Using a die provided with a through-hole, while introducing air for adjusting internal pressure into the hollow portion, the molten resin is extruded vertically downward from the die hole portion for forming the resin portion of the ultra-fine porous tube, and taken through a cooling step. (1) A slow cooling step in which an extruded product is drafted in a heated cylinder heated immediately below the die and below the vicinity of the melting point of the resin that forms the resin part at 40 ° C. or higher, and (2) Next, at least one stage of air-cooling zone near room temperature is provided, and the resin part is cooled to near room temperature by passing through air-cooling, or water-cooled as necessary after the air-cooling zone, near room temperature. A cooling step of cooling the extruded product until

  The second aspect of the method for producing an ultrafine porous tube according to the present invention is the same as the first aspect except that a die having an introduction hole for introducing an ultrafine wire into the central portion is used.

The die used in the first aspect of the method for producing an ultrafine porous tube according to the present invention has an opening as shown in FIGS. 2 (A) to (D) as viewed from the molten resin discharge surface side. Things are used. 2A to 2D correspond to the microporous tube whose cross section is shown in FIGS. Moreover, in the second aspect of the manufacturing method including an optical fiber or a tensile body linear object in the center, a hole-shaped die shown in FIG. 2 (C) is used.
In FIG. 2, the suffixes a to d of the symbols mean portions corresponding to the die holes 10 (A) to (D).
Each die hole portion 10 includes an outer annular portion hole 11, a rib portion hole 12, a hollow portion forming block 13, an inner annular portion hole 14, an introduction hole 15, a central core portion hole 17, and an internal pressure adjusting air introduction through-hole 20. Have.

FIG. 3 is a conceptual diagram showing an example of a method for producing an ultrafine porous tube according to the present invention. Reference symbol S indicates an apparatus for manufacturing an ultra-fine porous tube according to the present invention (hereinafter also referred to as “manufacturing apparatus”). In this manufacturing apparatus S, a die 10 having a hollow portion designed to obtain an ultrafine porous tube having a desired cross-sectional shape is attached to a crosshead 30 of a melt extruder, and a molten state is formed from an opening portion of the die. A thermoplastic resin is extruded as a melt-formed body 1 ′ and introduced into a heating cylinder 40 provided with heating means.
The heating cylinder 40 functions as a draft zone for preventing the melt-formed body 1 'from being rapidly cooled by the outside air and reducing the diameter to a desired outer diameter under suitable temperature conditions. Is controlled at 40 ° C. or higher and below the melting point of the thermoplastic resin used. The molded body drawn down and gradually cooled in the heating cylinder 40 is further air-cooled by the air-cooling zone 50, and then the surface temperature is measured by a non-contact thermometer 55. It introduces into the cooling tank 60 and is water-cooled. The cooled molded product is redirected by a turn sheave 70, passed through a Nelson roller 90, continuously measured by an oscillating outer diameter measuring device 95, and wound around a bobbin (not shown). In addition, when water cooling is performed in the water cooling tank 60, the water leaked from the water cooling tank 60 is processed in the water receiving tank 80.

On the other hand, in the manufacturing method of the microporous tube according to the second aspect in which the optical fiber or the tensile body linear object is provided in the central space, the optical fiber or the tensile body linear object wound around the bobbin 25 in FIG. Is continuously supplied via the guide roller 26, and this is guided to the introduction hole 15c of the die 10C having a hole shape shown in FIG. 2, for example, attached to the cross head 30, and melted from the opening portion of the die. The thermoplastic resin is extruded so as to cover the optical fiber or the tensile body linear material, and then introduced into the heating cylinder 40 provided with heating means as the melt-formed body 1 ′ in the same manner as described above.
The subsequent steps are the same as described above.

  The heating cylinder 40 (draft zone) heats the resin that forms the melt-formed body 1 ′ drawn down from the die 10. The heating temperature can be appropriately set according to the type of resin, the outer diameter of the microporous tube, and the like, and for example, the heating can be performed at a temperature lower than (the melting point of the resin + 10 ° C.) to 40 ° C. By passing the resin through the heating cylinder 40 having such a temperature, the microporous tube 1 having excellent roundness can be obtained even if the diameter is small. Even if the heat capacity of the molten resin extruded from the die hole portion 10 is small, rapid cooling and solidification of the molten resin can be prevented by passing the heating cylinder 40. The resin melting point can be measured according to ASTM D4591. And although the structure and heating method of the heating cylinder 40 are not limited, it is preferable to use high-frequency heating or far-infrared heating.

  The air cooling unit 50 gradually cools the resin forming the microporous tube 1 by air cooling in the vicinity of room temperature. By providing the air cooling part 50 after the heating cylinder 40, it is possible to prevent the resin forming the ultrafine porous tube 1 from being cooled and solidified at once. Although the temperature of the air cooling part 50 should just be room temperature vicinity, it is desirable that it is 15 to 40 degreeC more specifically, It is desirable to set it as 25 to 35 degreeC more preferably. In addition, the molten resin can be made into the target temperature by adjusting the length (air cooling zone) of the air cooling unit 50.

  The water cooling tank 60 water-cools the molded body that has passed through the air cooling unit 50. Thereby, the resin forming the ultrafine porous tube can be completely cooled and solidified. Although the water cooling tank 60 is not necessarily essential in the present invention, it is desirable to provide the water cooling tank 60 in addition to the air cooling unit 50 (or the air cooling unit). If it is an ultrafine porous tube, the temperature of the resin forming the ultrafine porous tube can be lowered to near room temperature by air cooling or air cooling as described above, but it is true even if the production rate is high by performing water cooling. An ultrafine porous tube with high circularity can be obtained. In particular, even when the drawing speed is 30 m / min or more, an ultrafine porous tube having high roundness can be suitably obtained.

  In addition, the maximum outer diameter and the minimum outer diameter of the obtained ultrafine porous tube 1 are measured, and the respective conditions of the heating cylinder 40 and the air cooling unit 50 are set so that the difference between the maximum outer diameter and the minimum outer diameter is minimized. It is desirable to control.

  The measurement of the maximum outer diameter and the minimum outer diameter can be performed by a swinging outer diameter measuring instrument 95. The oscillating type outer diameter measuring device 95 can measure the outer diameter of the microporous tube 1 continuously or intermittently. The oscillating outer diameter measuring device 95 measures the measuring device itself while reciprocating and rotating ± 90 °, and the microporous tube is online. The outer diameter can be measured in the entire circumferential direction. In the present invention, the type of measuring instrument is not limited, and the measuring instrument can be appropriately measured by a suitable measuring instrument and measuring method.

  About the heating cylinder 40, at least any one of the heating temperature and the heating time can be controlled. This can be achieved by adjusting the atmospheric temperature in the heating cylinder 40, the length of the cylinder (zone length), and the like. Furthermore, the heating timing of the heating cylinder 40 can be controlled. For example, in the case of the manufacturing apparatus S, as a structure that can be appropriately moved on a rail (not shown), the timing at which the molten resin extruded from the die hole portion 10 of the crosshead die 30 is heated is controlled. be able to. If the temperature is too low or the heating cylinder is too short, the outer ring of the hollow part tends to swell and form petals, and if the temperature of the heating cylinder is too high or the heating cylinder is too long, the outer ring of the hollow part is recessed and the rib part is apex. It tends to collapse into a polygonal shape. These conditions can be determined in consideration of the molding speed, the temperature measured by the non-contact thermometer 55, the size and shape of the microporous tube 1, and the like.

  About the air-cooling part 50, air-cooling conditions (air-cooling temperature and air-cooling time) can be controlled by adjusting the atmospheric temperature, the length (zone length) of an air-cooling part, etc. Further, it is desirable to control the air cooling timing of the air cooling unit 55. For example, in the case of the manufacturing apparatus S, the structure is movable as appropriate on the rail (not shown). be able to.

  In addition, at the start of manufacturing the heating cylinder 40, the air cooling unit 50, etc., on the rail in order to detect the optimal arrangement position (arrangement interval) based on the measurement result of the swinging outer diameter measuring device 95, After the optimum arrangement position is determined, it can be fixed to each optimum arrangement position (arrangement interval).

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example.

In the present invention, the area withdrawal magnification, the roundness, and the assumed outside diameter fluctuation rate were measured by the methods described below.
(1) Area withdrawal magnification Area withdrawal magnification (%) = (Outer diameter of outer annular part of die hole part) ² / (Outer diameter of extra-fine porous tube) ²
(2) Roundness of microporous tube The roundness is calculated when the longest diameter of the outer annular portion 14 is a, the shortest diameter is b, and the average outer diameter is c (c = (a + b) / 2) in FIG. , Which is a value represented by the following mathematical expression, indicating how close the microporous tube is to a perfect circle.
Roundness (%) = (1− (a−b) / c) × 100
(3) Deemed outer diameter fluctuation rate (CV value)
An oscillating laser outer diameter measuring instrument (LDM-903M, manufactured by Takikawa Engineering Co., Ltd.) that rotates the reciprocating angle of ± 90 ° around the central axis in 10 seconds while continuously manufacturing the obtained microporous tube. ), The outer diameter is measured at a measurement speed of 50 times per second for 40 seconds, and the average value of the outer diameters (number of measurements: 50) measured for 1 second is not regarded as the outer diameter. Further, continuously measure for 40 seconds, obtain the average value of the assumed outside diameter and its standard deviation, display the value (variation coefficient) divided by the outside diameter average value without looking at this deemed outside diameter standard deviation, and display the outside diameter fluctuation as a percentage. Rate (= CV value).
The definition of expression in the above is shown below.
Outer diameter: Measured value of outer diameter at one point at a certain point of time Deemed outer diameter: Average value of values obtained by measuring the outer diameter at a speed of 50 points / second for 1 second (measured average value of 50 points)
Average value of assumed outer diameter: Average value of assumed outer diameter in 40 seconds Considered outer diameter standard deviation: Standard deviation of assumed outer diameter in 40 seconds Considered outer diameter fluctuation rate (CV value) (%) = Considered outer diameter standard deviation / Deemed outer diameter average value × 100
When the ultrafine porous tube has a substantially polygonal cross-sectional shape, the longest portion of the diagonal line is regarded as the diameter of the circle, and the outside diameter variation rate is evaluated. Specifically, the oscillation is stopped at the rotational position where the value measured by the oscillation type laser outer diameter measuring device shows the maximum value (that is, the measurement at this position is the longest part of the diagonal of the polygon). The other methods are the same as described above, and the diagonal length is measured for 40 seconds at a measurement speed of 50 times per second, and the average value of the lengths (number of measurements: 50) measured in that second is ignored. Similarly, measure continuously for 40 seconds, find the average value of the assumed outside diameter and its standard deviation, and find the standard deviation of the assumed outside diameter without dividing the average value of the outside diameter (coefficient of variation) in%. Displayed and considered as the outside diameter variation rate (= CV value).

Example 1
In the apparatus S shown in FIG. 3, using the hole-shaped die 10C shown in FIG. 2C, the cross section shown in FIG. 1C has the outer diameter of 0.5 mm, the six ribs 2c and the inner A lotus root-shaped ultrafine porous tube having six fan-shaped hollow portions 3c and a central hollow portion 5c by an annular portion 4c is made of perfluoroalkoxy fluorine (PFA) resin (Mitsui Dupont Fluorochemical Co., Ltd., 420 HPJ, melting point: 305 ° C.). Produced. The melted PFA was extruded from a hole-shaped die 10C shown in FIG. 2C at 350 ° C. to obtain an ultrafine porous tube. The prototype was manufactured as follows.
The linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 90 ° C., the outside air temperature was 19 ° C., and the area withdrawal magnification was 280 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.50 mm, an assumed outside diameter standard deviation of 0.0070 mm, an assumed outside diameter variation rate of 1.40%, and a roundness of 96%.

Example 2
Using a die 10C having the same hole shape as in Example 1, compressed air (pressure 0.05 kg / cm ² ) was introduced from each of the air holes 20c and 15c, and the product was made of the same PFA as in Example 1 and the cross section was as shown in FIG. The ultrafine porous tube C) was produced. In this case, the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 210 ° C., the outside air temperature was 20 ° C., and the area withdrawal ratio was 772 times.
The obtained ultrafine porous tube had an assumed outer diameter average value of 0.20 mm, an assumed outer diameter standard deviation of 0.0030 mm, an assumed outer diameter fluctuation rate of 1.50%, and a roundness of 95%.

Example 3
Using the apparatus shown in FIG. 3, an ultrafine porous tube 1A made of the same PFA as in Example 1 having an outer diameter of 0.4 mm and two hollow portions 3a in the cross section shown in FIG. . The melted PFA resin was extruded from a hole-shaped die 10A shown in FIG. 2 (A) to obtain an ultrafine porous tube. In this case, the linear velocity is 30 m / min, the heating cylinder length is 250 mm, the in-cylinder heating temperature is 110 ° C., the outside air temperature is 20 ° C., and compressed air (pressure 0.05 kg / cm ² ) is introduced into the air hole 20a. However, the area withdrawal magnification was 437 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.40 mm, an assumed outside diameter standard deviation of 0.0060 mm, an assumed outside diameter fluctuation rate of 1.50%, and a roundness of 96%.

Example 4
Using the apparatus shown in FIG. 3, an ultrafine porous tube made of PFA having an outer diameter of 0.3 mm and three hollow portions 3b in the cross section shown in FIG. 1B was produced.
The melted PFA resin as in Example 1 was extruded from a hole-shaped die 10B shown in FIG. 2 to obtain an ultrafine porous tube. In this case, the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 150 ° C., the outside air temperature was 20 ° C., and the area withdrawal ratio was 776 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.30 mm, an assumed outside diameter standard deviation of 0.0050 mm, an assumed outside diameter variation rate of 1.67%, and a roundness rate of 95%.

Example 5
In Example 1, the PFA resin was changed to a polypropylene (PP) resin (Prime Polymer Co., Ltd., J106MG, melting point 160 ° C.) to produce an ultrafine porous tube having a cross section shown in FIG. The melted PP resin was extruded from a hole-shaped die 10C shown in FIG. 2C to obtain an ultrafine porous tube. The conditions at that time were as follows: the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 45 ° C., the outside air temperature was 19 ° C., and the area withdrawal ratio was 280 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.50 mm, an assumed outside diameter standard deviation of 0.0070 mm, an assumed outside diameter variation rate of 1.40%, and a roundness of 96%.

Example 6
In Example 1, the PFA resin was changed to a polymethyl methacrylate (PMMA) resin (Kuraray Co., Ltd., Parapet GF) to produce a microporous tube having a cross section shown in FIG.
The molten PMMA resin was extruded from a hole-shaped die 10C shown in FIG. 2 (C) to obtain an ultrafine porous tube. The conditions at that time were as follows: the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 50 ° C., the outside air temperature was 19 ° C., and the area withdrawal ratio was 280 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.50 mm, an assumed outside diameter standard deviation of 0.0070 mm, an assumed outside diameter variation rate (%) of 1.40%, and a roundness ratio of 96%.

Comparative Example 1
In Example 1, a heating cylinder was not used, the linear velocity was 30 m / min, the outside air temperature was 19 ° C., and cooling was performed at the ambient temperature of the outside air. The area withdrawal magnification was 280 times.
The obtained ultrafine porous tube had an assumed outside diameter average value of 0.50 mm, an assumed outside diameter standard deviation of 0.0132, an assumed outside diameter fluctuation rate (%) of 2.64%, and a roundness ratio of 84%. . The withdrawal was not stable, and the outer diameter fluctuation increased.

Comparative Example 2
In Example 2, a heating cylinder was not used, the linear velocity was 30 m / min, the outside air temperature was 20 ° C., and cooling was performed at the ambient temperature of the outside air. While introducing compressed air (pressure 0.05 kg / cm ² ) into the air holes, the area withdrawal magnification was set at 772 target.
The assumed outside diameter average value of the obtained microporous tube was 0.35 mm, the outside diameter standard deviation was 0.0200 mm, the outside diameter fluctuation rate was 5.71%, and the product outside diameter was set to 0.2 mm. The diameter could not be reduced.

Comparative Example 3
In Example 2, the linear velocity is 30 m / min, the heating cylinder length is 250 mm, the outside air temperature is 20 ° C., the in-cylinder heating temperature is 330 ° C., and while introducing compressed air (pressure 0.05 kg / cm ² ) into the air hole, The area withdrawal magnification was 772 times the target.
Although the average outer diameter of the obtained ultrafine porous tube was 0.20 mm and could be pulled down to the target diameter, the outer diameter was not stable. The assumed outside diameter standard deviation was 0.0100 mm, and the assumed outside diameter variation rate was 5.00%. It seems that the in-cylinder heating temperature was not stable because the melting point of the PFA resin was 305 ° C. or higher.

Example 7
A cross section shown in FIG. 1 (D) having an outer diameter of 0.5 mm and having 6 ribs, a tetrafluoroethylene / hexafluoropropylene copolymer (FEP) resin (Mitsui / DuPont Fluorochemical Co., Ltd., TE 9494, An ultrafine porous tube having a melting point of 260 ° C. was produced. The melted FEP resin was extruded from a hole-shaped die 10D shown in FIG. 2D to obtain an ultrafine porous tube. In this case, the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 90 ° C., the outside air temperature was 20 ° C., and the area withdrawal ratio was 280 times.
The obtained tube has an assumed outside diameter average value of 0.50 mm, the outside diameter of the central solid portion is 0.25 mm, the outside diameter standard deviation is 0.0070 mm, the outside diameter fluctuation rate is 1.40%, a perfect circle The rate was 96%.

Example 8
An ultrafine medical porous tube made of the same PFA resin as in Example 1 whose cross section is shown in FIG. 1 (E) and having a single mode quartz optical fiber having an outer diameter of 0.25 mm in the center was prepared.
In FIG. 3, a single-mode quartz optical fiber is inserted from the drum 25 through the guide roller 26 into the introduction hole 15c of the hole-shaped die 10C shown in FIG. While continuously pulling it down, the outer periphery was coated with PFA resin extruded at 350 ° C.
The linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 90 ° C., the outside air temperature was 20 ° C., and the area withdrawal magnification was 437 times.
The obtained ultrafine porous tube containing quartz optical fiber had an assumed outside diameter average value of 0.40 mm, an assumed outside diameter standard deviation of 0.0017 mm, an assumed outside diameter variation rate of 0.43%, and a roundness rate of 96%. .

Example 9
Using the apparatus shown in FIG. 3, the polymethylpentene resin (PMP resin; Mitsui Chemicals, TPX, RT18, melting point) having a cross section shown in FIG. 1 (F) having an outer diameter of 0.5 mm and six ribs: An ultrafine porous tube made at 237 ° C. was produced. The melted PMP resin was extruded from a hole-shaped die 10C shown in FIG. 2C to obtain an ultrafine porous tube. In this case, the linear velocity was 30 m / min, the heating cylinder length was 250 mm, the in-cylinder heating temperature was 200 ° C., the outside air temperature was 19 ° C., and the area withdrawal ratio was 280 times.
The obtained ultra-fine porous tube had a substantially hexagonal shape with the rib portion at the top. The outside diameter of the rib portion was taken as the outside diameter, the assumed outside diameter average value was 0.50 mm, the outside diameter standard deviation was 0.0070 mm, and the outside diameter fluctuation rate was 1.40%. In addition, the cross-sectional shape of this example is not a circle but a substantially hexagon, and it is not appropriate to evaluate the roundness, but the roundness was 90% according to the definition in the present invention.
The reason for the hexagonal shape was that the in-cylinder heating temperature was set to a high temperature close to the melting point (237 ° C.) of PMP, so that cooling was insufficient, the rib was the apex, and the outer annular part entered the inside, resulting in a hexagonal shape. It is considered a thing.

The results of the above examples and comparative examples are summarized in Table 1 and Table 2.

  The ultrafine porous tube of the present invention as described above can be used as a functionally improved tube in various applications, for example, as shown below: (1) Deaeration tube, (2) Medical tube, (3) In addition, it can be effectively used as an ultrafine porous tube for precision analysis.

(1) Degassing tube For example, in a liquid chromatograph or the like, it is necessary to remove (degas) the gas dissolved in the reagent solution (solvent, sample solution, etc.) during transfer. A vacuum deaerator is used to remove dissolved gas from a liquid (liquid to be deaerated) in various physics / analysis equipment and various production process facilities including pharmaceuticals, semiconductors, liquid crystals and the like.
In the deaeration device, an ultrafine deaeration tube using a fluororesin or the like that passes only gas and blocks the permeation of the liquid is used at a portion in contact with the sample solution, solvent, buffer solution or the like.
In order to improve the degassing efficiency of this type of vacuum degassing apparatus, it is necessary to increase the diffusion efficiency of the gas component. Since gas diffusion follows the diffusion equation, the efficiency increases exponentially as the diffusion movement distance is shorter. That is, it is preferable to move the degassed liquid passing through the degassing tube to a position as close as possible to the membrane surface (inner peripheral surface of the tube) rather than the central portion of the degassing tube.
Since the microporous tube of the present invention has a solid part or a hollow part at the center and a hollow part through which the degassed liquid can pass is arranged on the outer periphery thereof, the degassed liquid in the hollow part is efficient. Well deaerated.

(2) Medical tube A very thin catheter is used as a catheter for clinical experiments using mice. An angiography catheter that is inserted into a blood vessel in the human body is also required to be very thin. In addition, a catheter capable of providing a sensor function while arranging an ultrafine silica optical fiber and simultaneously treating an affected area has been studied. The diameter of the optical fiber sensor is 0.25 mm or less, and the outer diameter of the catheter is required to be 0.6 mm or less.
In the case of the microporous tube of the present invention, other signal lines (such as copper wires) can be introduced into the plurality of hollow portions. Moreover, it can also be set as the space for administering a chemical | medical agent. In other words, it is possible to use it as an ultra-thin catheter with an optical fiber in the center, and signal lines can be inserted into multiple spaces around it, and the affected area can be inspected and treated at the same time. is there.

(3) In addition, for analysis technology in the life science and medical fields, such as for precision analysis, technology related to high-speed microfeeding of sample solutions may become an important elemental technology. There is a demand for liquid feeding at the nanoliter level or even at the femtritor level.
Technologies for exhaustively analyzing a large number of environmental and biosamples, such as mass spectrometers and DNA microarrays, are maturing, but currently used liquid feeding methods use a single capillary with a single space. This is a method, and when a plurality of liquid delivery is desired, a plurality of liquid delivery systems must be used, and a liquid delivery system is also required. The analysis system becomes very complicated, for example, when there are a large number of samples to be analyzed. There is a possibility that the analysis system can be simplified by using the ultrafine porous tube of the present invention and using a system in which different liquids are sent to the respective holes.

Small two-fluid nozzle, electrospray nozzle When the center is a gas flow path, it can be used as an ultra-fine two-fluid nozzle for feeding liquid that wants to fly in the center. There is a method of applying the electrospray phenomenon in mass spectrometry of proteins, etc., and sending a very small amount of sample to the detection part, but the gas is said to be nepelizer gas. A glass capillary is used for the liquid feeding part, and by inserting the capillary in the central space of the ultrafine porous tube, the direction of the gas can be maintained, so that the liquid (mist) can be prevented from spreading and spreading, A small amount of sample can be reliably supplied to the target portion.

  The method for producing an ultrafine porous tube of the present invention can be effectively used as a method for continuously producing the above useful ultrafine porous tube stably and accurately.

DESCRIPTION OF SYMBOLS 1, 1A-1F Extra-fine porous tube 1a-1f Outer annular part 2, 2a-2f Rib part 3, 3a-3f Hollow part 4, 4c, 4e, 4f Inner annular part 5c, 5f Central space part 5e Optical fiber 6d Solid part 10, 10A-10D Die hole shape 11, 11a-11d Outer annular hole 12, 12a-12d Rib hole 13, 13a-13d Hollow part forming region 14, 14c Inner annular hole 15, 15c Optical fiber, tensile strength linear Material introduction pipes 17 and 17d Central resin enhancement part holes 20 and 20a to 20d Internal pressure adjusting air introduction hole 25 for forming hollow part Optical fiber, tensile body winding bobbin 26 Guide roller 30 Crosshead die 40 Heating cylinder 50 Air cooling section 55 Non-contact thermometer 60 Water cooling tank 70 Turn sheave 80 Receiving tank 90 Nelson roller (take-up machine)
95 Oscillating outer diameter measuring instrument S Manufacturing equipment

Claims (4)

It is made of a thermoplastic resin, and the outer shape of the cross section is substantially circular, polygonal, or elliptical, the assumed outer diameter average value is 0.5 mm or less, and has two or more continuous hollow portions in the longitudinal direction. Designed to obtain an ultrafine porous tube with a desired cross-sectional shape when producing an ultrafine porous tube with a directionally assumed outer diameter fluctuation rate of 2% or less and a roundness of 90% or more. Using a die provided with a through hole for introducing the internal pressure adjusting air for forming the hollow part in the part, melting from the die hole part for forming the resin part of the microporous tube while introducing the internal pressure adjusting air into the hollow part Extruding the resin vertically downward, taking a cooling step, a manufacturing method,
The production method includes the following steps (1) to (2): A method for producing an ultrafine porous tube.
(1) Area reduction ratio 280 to 776 defined below while heating and cooling the extruded product in a heating cylinder that is in contact with the die and heated to a temperature below the melting point of the resin that forms the resin part at 40 ° C. or higher. An annealing process that is pulled down
(2) Next, at least one stage of air cooling zone near room temperature is provided, and the resin part is cooled to near room temperature by passing it through air cooling, or it is further cooled with water as needed and extruded to near room temperature. A cooling process that cools things.
[Area withdrawal magnification: Area withdrawal magnification (times) = (outer diameter of outer annular portion of die hole portion) ² / (outer diameter of microporous tube) ² ]   The transverse section includes a central space portion, an inner annular portion surrounding the central space portion, a plurality of rib portions extending radially from the inner annular portion, and an outer annular portion connecting between outer ends of the rib portions, 2. The method for producing an ultrafine porous tube according to claim 1, wherein the microporous tube has a cross-sectional lotus root shape having a plurality of hollow portions surrounded by inner and outer annular portions and rib portions. An outer annular portion made of a thermoplastic resin and having a transverse cross section that connects between a central space portion, an inner annular portion surrounding the central space portion, a plurality of rib portions extending radially from the inner annular portion, and outer ends of the rib portions. A cross-sectional lotus root shape having a plurality of hollow portions surrounded by the inner and outer annular portions and rib portions, and an optical fiber for image transmission or high-speed signal transmission in the central space portion, Alternatively, an ultra-fine porous material having an ultra-thin linear object composed of a tensile-strength linear object and having an assumed outer diameter average value of 0.5 mm or less, a assumed outer diameter fluctuation rate in the longitudinal direction of 2% or less, and a roundness of 90% or more. When manufacturing tubes,
It has an introduction hole for introducing the ultrafine wire in the center, and is designed to obtain an ultrafine porous tube of the desired shape, for the introduction of air pressure adjusting air for forming the hollow part into the part corresponding to the die forming the hollow part A die hole for forming a resin portion of a microporous tube around the introduction hole while inserting air for adjusting internal pressure into the hollow portion and using a die provided with a through hole Extruding the molten resin vertically from the part, and taking it while covering with a resin part having a plurality of hollow parts,
The production method includes the following steps (1) and (2): A method for producing an ultrafine porous tube.
(1) An area reduction rate of 280 to 776 as defined below while heating and cooling the extruded product in a heating cylinder that is in contact with the die and heated to a temperature below the melting point of the resin forming the resin part at 40 ° C. or higher. An annealing process that is pulled down
(2) Next, at least one stage of air cooling zone near room temperature is provided, and the resin part is cooled to near room temperature by passing it through air cooling, or it is further cooled with water as needed and extruded to near room temperature. A cooling process that cools things.
[Area withdrawal magnification: Area withdrawal magnification (times) = (outer diameter of outer annular portion of die hole portion) ² / (outer diameter of microporous tube) ² ] The said thermoplastic resin consists of 1 type of thermoplastic resins selected from a fluororesin, a polyolefin resin, a polyimide resin, a polyamide resin, a polyester resin, a polystyrene resin, and a vinyl chloride resin. Manufacturing method of ultra-fine porous tube.

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