JP2008120035A - Manufacturing method of solid matter containing polytetrafluoroethylene and manufacturing method of polytetrafluoroethylene molded object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method, of a polytetrafluoroethylene (PTFE) molded object, which shows higher productivity and can make the shaping of the molded object to be obtained more widely optional, compared with a conventional manufacturing method of the PTFE, and a manufacturing method of the solid matter containing the PTFE to be obtained as an intermediate product during manufaturing the PTFE molded object. <P>SOLUTION: In the method for obtaining the solid matter encapsulating water and a surfactant, first, the PTFE particles are collided with each other by applying a mechanical force to a dispersion of the PTFE particle containing a nonionic surfactant with T1°C clouding point and water as a dispersing medium. Thus, the temperature of the dispersion is increased by heat generated at the time of collision, and the PTFE particles are made to bind each other within the temperature range of (T1-30)°C or higher in terms of the temperature of the dispersion. The above manufacturing method can be executed by a chamber (1) shown in Fig. 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a PTFE-containing solid material and a method for producing a PTFE molded article, which use a dispersion of polytetrafluoroethylene (PTFE) particles as a starting material.

  Polytetrafluoroethylene (PTFE) has characteristics such as high chemical resistance and low dielectric constant, and has a high melting point and excellent heat resistance. Therefore, it is used in a wide range of applications mainly in the chemical and electrical fields. . Further, it is widely used for mechanical applications such as a member used for a non-lubricated sliding portion by utilizing a characteristic with a small coefficient of friction and surface tension.

On the other hand, PTFE does not dissolve in most solvents except for special solvents, and its melt viscosity is as high as about 10 ¹⁰ to 10 ¹¹ Pa · s (10 ¹¹ to 10 ¹² P) at 380 ° C. For this reason, it is difficult to apply various molding methods (extrusion molding, injection molding, etc.) used for molding a general thermoplastic resin to manufacture a PTFE molded body. In these molding methods, the melt viscosity of the resin during molding is usually about 10 ² to 10 ³ Pa · s.

  Conventionally, as a method for producing a PTFE molded body, a method called a sintering molding method is generally used. In the sintering molding method, powdery PTFE particles are used as a starting material, and after preforming at room temperature (a molding aid may be added if necessary), the formed preform is converted into PTFE. The whole is sintered (fired) by heating to a melting point (327 ° C.) or higher to obtain a PTFE molded product.

  The details of the steps in the sintering molding method may be appropriately selected according to the shape of the molded body to be obtained. For example, when obtaining a sheet-like PTFE molded body (PTFE sheet), a cylindrical PTFE molded body (PTFE block) ) May be formed by preforming and firing, and the outer peripheral portion of the formed block may be cut (cutting method). According to this method, a sheet having a relatively large thickness (for example, 25 μm or more) can be obtained, but in order to efficiently manufacture the sheet, it is necessary to increase the size of the block. In order to suppress the occurrence of cracks and the like, a long time (approximately 2 to 5 days, depending on the size of the block) is required for preforming and firing. In addition, the sintering method including the cutting method is basically a batch production method, and it is difficult to continuously produce a PTFE molded body from a starting material.

  Apart from the cutting method, a casting method is known as a method for producing a PTFE sheet. In the casting method, a dispersion of PTFE particles (PTFE dispersion) as a starting material is applied onto a support such as a metal plate, dried and fired, and then peeled from the support to obtain a PTFE sheet. According to this method, a PTFE sheet that is thinner and has no distortion can be obtained as compared with the case where the sintering molding method is used. However, the thickness of the sheet obtained by one application, drying and firing is limited to about 20 μm in order to suppress a minute defect called a mud crack, and in order to obtain a sheet having a thickness exceeding 20 μm. It is necessary to repeat the application and baking of the dispersion several times. Moreover, in the casting method, it is difficult to form a molded body having a shape other than the sheet shape.

  For example, Non-Patent Document 1 (pages 141 to 142 for the cutting method and page 130 for the casting method) describes the cutting method and the casting method and other methods for producing a PTFE molded body.

Although not a method for producing a PTFE molded product, secondary particles having a particle size larger than the particles (for example, for example, by applying mechanical force to a dispersion of PTFE particles or a dispersion of a fluorinated thermoplastic resin) Patent Documents 1 to 3 disclose a method for producing PTFE fine powder. Further, Patent Document 4 discloses a method for producing PTFE secondary particles having a particle size larger than that of the particles by applying mechanical force after the PTFE particles are wetted with an aqueous solution containing a surfactant. ing.
Fluorine resin handbook, edited by Takaomi Satokawa, published by Nikkan Kogyo Shimbun, 1990 JP 2002-201217 A JP-A-6-192321 Special table 2003-522230 gazette JP 47-12332 A

  Thus, in the conventional method for producing a PTFE molded product, there is a limit to the improvement in productivity, and the shape of the molded product obtained is limited. Therefore, the present invention provides a PTFE molded body manufacturing method that is superior in productivity to these conventional PTFE molded body manufacturing methods and has a high degree of freedom in the shape of the resulting molded body, and a PTFE molding based on the manufacturing method of the present invention. It aims at providing the manufacturing method of the PTFE containing solid substance obtained as an intermediate product when manufacturing a body.

  The method for producing a polytetrafluoroethylene (PTFE) -containing solid according to the present invention is a dispersion of PTFE particles comprising PTFE particles, a nonionic surfactant having a cloud point of T1 ° C., and water as a dispersion medium. The particles are caused to collide with each other by applying a mechanical force, and the temperature of the dispersion is increased by the heat generated during the collision, and the temperature of the dispersion is (T1-30) ° C. or higher. In this method, the particles are bound together to obtain a solid that contains the water and the surfactant.

  The method for producing a PTFE molded article of the present invention includes a step of obtaining a PTFE-containing solid by the above-described method of producing a PTFE-containing solid of the present invention, and a step of reducing the amount of water contained in the obtained solid. including.

  According to the present invention, the PTFE molded body can be manufactured with higher productivity than the conventional PTFE molded body manufacturing method, and the degree of freedom of the shape of the obtained molded body can be increased. Moreover, according to this invention, the PTFE containing solid substance which encloses water and surfactant can be obtained as an intermediate product at the time of manufacturing a PTFE molded object.

  According to the method for producing a PTFE-containing solid material of the present invention, a PTFE-containing solid material (hereinafter also simply referred to as “solid material”) including water as a dispersion medium and a surfactant can be obtained. As apparent from the manufacturing method, this solid is an aggregate formed by binding PTFE particles. Such a solid cannot be obtained as an intermediate product in the conventional method for producing a PTFE molded product. For example, as in the production method of the present invention, in the casting method using a dispersion of PTFE particles as a starting material, water is removed by drying in a state where the PTFE particles are dispersed, so that water and a surfactant are included. A solid is not formed.

  Such a solid substance cannot be obtained as an intermediate product even in the conventional method for producing secondary particles as disclosed in Patent Documents 1 to 4. In the methods disclosed in Patent Documents 1 to 3, although mechanical force is applied to the dispersion liquid of the fluorinated thermoplastic resin particles or the dispersion liquid of PTFE particles as the starting material, the particles collide with each other, No force is applied to raise the temperature of the dispersion due to the heat generated during the process. In the method disclosed in Patent Document 4, the starting material is not even a dispersion of PTFE particles, and a mechanical material that raises the temperature of the mixture of the PTFE powder that is the starting material and the aqueous solution in the method as described above. No power is applied.

  According to the production method of the present invention, the PTFE particles are bound to such an extent that the imparted shape is retained (has self-shape retaining properties), and the shape is deformable (has deformability). A solid material containing water can be obtained. This solid can basically be deformed into an arbitrary shape until it is dried or fired, for example, by transforming the obtained solid into a sheet and then drying and / or firing. A PTFE sheet can be obtained. The PTFE-containing solid material according to the present invention is also characterized by a large range that can be deformed without breaking.

  According to the production method of the present invention, a solid material in which PTFE particles are bound to such an extent that they are not dispersed in water can be obtained. In the method of Patent Document 2, a solidified phase (concentrated slurry) that can be diluted with water is obtained (described in paragraph No. [0008] of Patent Document 2), but the solid obtained by the production method of the present invention is a patent document. It cannot be diluted with water like the solidified phase of 2.

  According to the production method of the present invention, it is possible to obtain a solid material in which PTFE particles are bound to such an extent that re-particulation does not occur due to a decrease in the amount of water included. In the methods of Patent Documents 1 to 3, particle aggregates obtained by applying a mechanical force (for example, a force for precipitating PTFE particles in a dispersion) to a dispersion of fluorinated thermoplastic resin particles or a dispersion of PTFE particles. The body is dried to obtain secondary particles, but even if the solid of the present invention is dried, it does not become PTFE secondary particles.

  The reason why such a solid can be obtained by the production method of the present invention is not clear, but probably a PTFE phase and an aqueous phase in which PTFE particles are bound to each other by the action of the surfactant in the dispersion. This is thought to be due to the formation of a mixed structure. In addition, this action applies mechanical force to the dispersion of PTFE particles to cause the particles to collide with each other, and raises the temperature of the dispersion by heat generated at the time of collision, and sets the temperature of the dispersion (T1). It is considered that it can be obtained only by binding the particles in a temperature range of −30) ° C. or higher.

  Although the specific mechanism by which such a solid is obtained by such treatment on the dispersion of PTFE particles is not clear, collision of PTFE particles with each other by application of mechanical force to the dispersion occurs. A mechanism is considered in which the properties of the surfactant contained in the dispersion change when the temperature enters a specific temperature range, and the PTFE phase is formed to some extent continuously. In some cases, a stronger binding structure may be formed between PTFEs, or a part of PTFE may be fibrillated to form a PTFE network structure. In addition, in the formation of such a PTFE phase, unlike other fluorinated thermoplastic resins, PTFE can be bonded to each other even in a temperature range below its melting point, and a fine structure such as fibril can be formed. Are also considered to contribute.

  The dispersion of PTFE particles (hereinafter referred to as “PTFE particle dispersion”, also simply referred to as “dispersion”), which is a starting material in the production method of the present invention, contains a nonionic surfactant. Nonionic surfactants usually have a cloud point T1 (° C.). The characteristics of the nonionic surfactant greatly change at the cloud point. For example, the function as the surfactant is lost in the temperature range above the cloud point. In addition, the characteristics of the aqueous solution containing a nonionic surfactant at the cloud point are also greatly changed, and for example, the viscosity of the solution that increases with increasing liquid temperature rapidly decreases at the cloud point.

  In the production method of the present invention, PTFE particles are bound to each other in a temperature range of (T1-30) ° C. or higher as the temperature of the dispersion.

  In the production method of the present invention, the temperature of the dispersion is (T1-10) ° C. or higher, (T1-5) ° C. or higher, or (T1-3) ° C. or higher. PTFE particles may be bound together. In the above order, physical properties (for example, tensile strength) of the obtained solid can be improved.

  In the production method of the present invention, the PTFE particles may be bound to each other in a temperature range of T1 ° C. or higher as the temperature of the dispersion.

  In the production method of the present invention, PTFE particles are caused to collide with each other, the temperature of the dispersion is increased by heat generated during the collision, and the temperature of the dispersion is set to a specific temperature range to obtain the solid matter. However, in order to set the temperature of the dispersion to the specific temperature range, a heat source other than the collision of particles, for example, some heat source such as a heating device may be used.

The method for applying a mechanical force to the dispersion is not particularly limited, and for example, the following method may be used.
A. The dispersion is supplied to the chamber, and the above force is applied in the chamber.
B. The force is applied by spraying the dispersion onto the target.
C. The force is applied by bringing the dispersion into contact with a barrier arranged in the flow path of the dispersion to prevent the dispersion from flowing.

  In Method A, the pressure generated in the chamber as the dispersion is supplied can cause PTFE particles to collide with each other more reliably, and the thermal energy generated by the collision between the particles can be used to raise the temperature of the dispersion. Can be used more efficiently. In Method A, as will be described later, it is possible to connect a tube body (first tube body) that discharges the solid matter formed in the chamber.

  In Method A, the dispersion liquid supplied to the chamber may be sprayed in the chamber (Method A1) or passed through a constriction provided in the chamber (Method A2).

  In the method A1, the dispersion may be sprayed, for example, toward the inner wall of the chamber or the object in the chamber. By causing the dispersion liquid to collide with the inner wall or the object, the kinetic energy of the particles can be converted into thermal energy, and the temperature of the dispersion liquid can be increased.

  In the method A1, depending on the structure and shape of the chamber, the spraying condition of the dispersion, and the like, the dispersion and the solid material formed in the chamber can collide with each other. In this case, the PTFE phase formed by binding the PTFE particles to each other can be more reliably formed, and the temperature of the dispersion can be more reliably increased.

  The dispersion liquid may be ejected from a nozzle having an ejection port, and the structure and shape of the nozzle, for example, the shape of the ejection port can be freely set. Similarly, in the method B, the dispersion may be ejected from a nozzle having an ejection port. The target in method B can be set freely, but the target is arranged in order to suppress the scattering of the injected dispersion and increase the ratio of the amount of solids obtained relative to the amount of the injected dispersion. It is preferable that the degree of sealing of the space to be formed is high.

  The pressure for injecting the dispersion may be freely set depending on the content of PTFE particles in the dispersion, the content of the surfactant, the shape of the chamber, the internal volume, etc. If the pressure is too low, May be difficult to obtain.

  In the method A2, the shape of the constriction part through which the dispersion liquid passes is not particularly limited, and may be, for example, a slit shape.

  The dispersion liquid may be supplied to the chamber via two or more supply paths, and the dispersion liquid supplied from the two or more supply paths may collide with each other in the chamber (Method A3).

  In order to cause the dispersion liquid to collide with each other in the chamber, for example, the dispersion liquid may be sprayed from a nozzle disposed at each end of the two or more supply paths. At this time, by disposing at least two nozzles in the chamber so that the respective injection directions intersect, the dispersions can collide with each other more efficiently.

  In the method C, the dispersion may be supplied to, for example, a tubular body (second tubular body) having the barrier and the force may be applied. When the dispersion liquid passes through the barrier disposed in the flow path (second tube), the flow of the dispersion liquid is disturbed, or the dispersion liquid partially stays in the dispersion liquid. A pressure imbalance occurs, and the force that the PTFE particles collide with each other is applied to the dispersion, and the temperature of the dispersion can be increased.

  The barrier may be, for example, a plate-like member disposed so as to narrow the flow path inside the second tubular body. The barrier can also be formed by bending the second tube or partially reducing its inner diameter. That is, the barrier may be a bent portion or a narrowed portion of the second tubular body. In this case, the method C supplies the dispersion liquid to the second tubular body having the bent portion or the narrowed portion, and the bent portion. It can also be said that this is a method of applying the above force at the part or the constriction part.

  When supplying the dispersion liquid to the second tubular body, the dispersion liquid may be sprayed and supplied from a nozzle, and in this case, the force that the PTFE particles collide with each other can be efficiently applied to the dispersion liquid. The nozzle used for the injection may be the same as in method A1, and the pressure at which the dispersion is injected from the nozzle depends on the PTFE particle content, the surfactant content, the shape of the second tubular body, etc. in the dispersion. It can be set freely.

  In Method C, depending on the structure and shape of the second tube, the supply condition of the dispersion, and the like, the dispersion and the solid matter formed in the second tube can be collided.

  The shape, the inner diameter, the length of the second tubular body, the shapes of the bent portion and the narrowed portion, etc. are not particularly limited.

  Methods A1 to A3, Method B and Method C are examples of a method for applying the above force to the dispersion of PTFE particles, and the production method of the present invention is not limited to the case where the methods shown in the above examples are used.

  The configuration of the chamber for applying the force to the dispersion liquid including the shape and the internal volume is not particularly limited, but a commercially available device (for example, an optimizer manufactured by Sugino Machine) may be applied. The optimizer is originally a pulverizing / dispersing device that pulverizes and atomizes various materials such as pigments, fillers, and catalysts, and the present inventors have found an application for obtaining a PTFE-containing solid.

  An example of the chamber is shown in FIG. The chamber 1 shown in FIG. 1 has a substantially conical shape in which the inner space 2 is cut off at the periphery near the bottom surface, and a pair of nozzles 3a and 3b for injecting a dispersion liquid are provided on the periphery. The injection port is arranged so as to face the internal space 2. The nozzles 3a and 3b are in a positional relationship where the respective injection directions 4a and 4b intersect each other. The dispersion liquid can be supplied from the supply port 7 to the nozzles 3 a and 3 b via supply paths 6 a and 6 b formed inside the structure 5 of the chamber 1. A discharge port 8 for discharging solid matter formed in the chamber 1 (inside the internal space 2) is formed in the vicinity of the apex of the internal space 2 having a substantially conical shape. The shape of the discharge port 8 is not particularly limited, and may be, for example, a circular shape.

  In the chamber 1 shown in FIG. 1, the pressurized dispersion liquid is supplied to the nozzles 3a and 3b via the supply port 7 and the supply paths 6a and 6b, so that the dispersion liquid is injected into the internal space 2 and collides with each other. (Method A3 can be realized). Further, by using the chamber 1 having the same structure, the number of nozzles to be arranged is one, or by controlling the injection directions 4a and 4b of the nozzles 3a and 3b, the dispersion liquid is injected into the internal space 2, It can be made to collide with the inner wall of the chamber 1 (the wall surface of the inner space 2) (method A1 can be realized).

  The chamber 1 preferably has a sealable structure, and the force can be applied to the dispersion more efficiently by sealing the chamber 1 as necessary. The chamber 1 may be provided with a pressure adjusting port for adjusting the pressure in the internal space 2 as necessary. For example, a pressure adjusting valve may be disposed in the pressure adjusting port. . The same applies to the chamber 1 shown in FIGS.

  A method for supplying the pressurized dispersion liquid to the nozzles 3 a and 3 b is not particularly limited. For example, the dispersion liquid pressurized by a high-pressure pump may be supplied from the supply port 7. Using the chamber 1 as shown in FIG. 2, the dispersion and the water pressurized by the pump (pressurized water) are supplied to the mixing valve 9 provided immediately before the nozzles 3a and 3b via mutually different supply paths. And after mixing both with the mixing valve 9, you may supply to nozzle 3a, 3b. In the chamber 1 shown in FIG. 2, pressurized water is supplied to the mixing valve 9 via the supply port 7 and the supply paths 6a and 6b, and the dispersion is supplied to the mixing valve 9 via the supply ports 17a and 17b and the supply paths 16a and 16b. .

  Another example of the chamber is shown in FIG. In the chamber 1 shown in FIG. 3, a freely rotatable sphere 10 is arranged at one end of the internal space 2, and a nozzle 3 for injecting the dispersion liquid is provided at the other end of the injection port. Are arranged so as to face the internal space 2. The nozzle 3 and the sphere 10 are in a positional relationship where the injection direction 4 of the nozzle 3 intersects the sphere 10. The dispersion liquid can be supplied to the nozzle 3 from the supply port 7 via the supply path 6 formed inside the structure 5 of the chamber 1. On the wall surface between the nozzle 3 and the sphere 10 in the internal space 2, a discharge port 8 is formed for discharging solid matter formed in the chamber 1 (inside the internal space 2).

  In the chamber 1 shown in FIG. 3, by supplying the pressurized dispersion liquid to the nozzle 3 through the supply port 7 and the supply path 6, the dispersion liquid is sprayed into the internal space 2 and disposed in the chamber 1. Can collide with a spherical body 10 (which is an object in the chamber 1) (method A1 can be realized). At this time, by disposing the nozzle 3 and the sphere 10 so that the injection direction 4 of the nozzle 3 deviates from the center of the sphere 10, the sphere 10 can be rotated by the dispersion liquid injection, and the chamber 1 due to the collision of the dispersion liquid. Internal wear can be suppressed.

  The sphere 10 is preferably made of a material that does not deform due to the collision of the dispersion liquid. For example, the sphere 10 may be made of ceramic, metal (preferably alloys having high hardness), diamond, or the like.

  Another example of the chamber is shown in FIG. In the chamber 1 shown in FIG. 4, a pair of cores 12 a and 12 b are accommodated inside a cylindrical outer peripheral body 11. Each of the cores 12a and 12b has a shape in which a truncated cone is joined to one end surface of the cylindrical body, and the upper surfaces 13a and 13b of the truncated cones in each of the cores are spaced apart by a certain distance d. It arrange | positions so that it may mutually oppose. The central axes of the outer peripheral body 11 and the cores 12a and 12b are substantially the same. A supply port 7 for supplying the dispersion liquid is formed at one end of the outer peripheral body 11. The outer diameter of the core 12 a close to the supply port 7 is smaller than the inner diameter of the outer peripheral body 11 and is far from the supply port 7. The outer diameter of the child 12 b is the same as the inner diameter of the outer peripheral body 11. Further, the core 12 b is formed with a discharge path 14 that passes from the center of the upper surface 13 b to the inside of the core 12 b and communicates with the outside of the chamber 1. The core 12a is supported by the outer peripheral body 11 via a support member (not shown).

  By adjusting the positions of the cores 12a and 12b and appropriately controlling the value of the distance d, the gap 15 between the upper surfaces 13a and 13b can be made into a slit-like constriction, and a pressurized dispersion liquid is supplied. By supplying to the chamber 1 from the port 7, the dispersion liquid can be passed through the narrowed portion (gap 15) disposed in the chamber (method A2 can be realized). The dispersion liquid passes through the gap 15 and then flows into the discharge path 14 and is discharged from the discharge port 8 of the chamber 1 as PTFE-containing solid matter.

  The pressure of the dispersion to be supplied (supply pressure) may be freely set depending on the shape and inner volume of the chamber, the size of the interval d, the amount of the dispersion to be supplied, etc. If the supply pressure is too low, It may be difficult to obtain things.

  1-4, a tubular body (first tubular body) is connected to the discharge port 8 in each chamber 1 and solids are discharged from the connected tubular body while being in contact with the entire inner wall of the tubular body. It is preferable to do. When the solid matter discharged from the discharge port 8 passes through the first tubular body, it is possible to further apply a force for binding the PTFE particles to each other, more excellent in self-shape retention, and mechanical properties such as strength. Can be obtained.

  Further, such a solid material can be formed into a molded body having improved mechanical properties such as strength. For example, by selecting the shape, inner diameter, length, etc. of the first tubular body, A molded body having a tensile strength in the MD direction (flow direction: in this case, the direction of discharging from the tube) of 1 MPa or more, and in some cases 2 MPa or more, or 2.5 MPa or more can be obtained. The reason why the strength of the solid and the molded body is improved is that a skin layer in which the PTFE particles are more firmly bound to each other is formed on the surface of the solid and the molded body by passing through the first tubular body. Conceivable. It is also conceivable that a shear force is generated inside the solid due to the frictional force generated between the first tubular body and the surface of the solid, and further binding between the PTFE particles is promoted. In order to discharge the solid matter while making contact with the entire inner wall of the tube, the shape and diameter of the discharge port 8, the shape, inner diameter, length, and the like of the tube may be selected.

  The shape, inner diameter, length, and the like of the first tubular body to be connected are not particularly limited, and can be freely set according to the shape and inner volume of the chamber 1, the amount of the dispersion liquid supplied to the chamber 1, and the like. Basically, the longer the tubular body, the better the self-shape retention property and mechanical properties of the obtained solid matter tend to be improved. Therefore, it is preferable that the length of the tubular body is larger than the minimum inner diameter of the tubular body. As an example, when the treatment speed of the dispersion is about 0.1 to 0.5 L / min, the inner diameter of the tube connected to the chamber 1 is in the range of about 1 mm to 10 mm, and the length of the tube is about 1 mm to 5000 mm. It may be a range. In the chamber 1 shown in FIG. 4, depending on the shape of the discharge path 14, the discharge path 14 can also serve as the tube.

  In order to apply force to the solid more efficiently, it is preferable that the minimum inner diameter of the first tubular body is equal to or smaller than the diameter of the discharge port 8. Further, it may be a tubular body whose inner diameter gradually changes as it moves away from the discharge port 8 (that is, the inner surface is tapered). In this case, it is preferable that the inner diameter gradually decreases as it moves away from the discharge port 8.

  You may further deform | transform the solid substance obtained by the manufacturing method of this invention, for example, the solid substance discharged | emitted from the discharge port 8 shown in FIGS. The shape of the deformation and the method of deforming are not particularly limited. For example, a string-like solid can be obtained by passing the first tubular body, and a sheet-like solid can be obtained by passing the slit. Alternatively, the solid material may be passed through various dies (die) used for extrusion molding, and solid materials having various shapes such as a string shape, a sheet shape, and a fiber shape are obtained by selecting the shape of the die. be able to. For example, the solid material deformed into a string shape, a sheet shape, or a fiber shape may be further deformed by stretching, rolling, or the like.

  Similarly to the above, the solid matter discharged from the second tubular body used in the method C may be further modified.

  Thus, according to the production method of the present invention, the degree of freedom of the shape of the obtained solid can be increased, for example, the minimum thickness of the obtained solid is 20 μm or more, depending on the production conditions, exceeds 20 μm, It can be 1 mm or more, or 2 cm or more. Conversely, the maximum thickness of the obtained solid material can be 5 cm or less. In addition, the thickness of a solid substance shows the diameter, for example, when a solid substance is a string form, and the thickness when a solid substance is a sheet form.

  The minimum thickness and the maximum thickness of the obtained solid matter are the diameter of the discharge port 8, the (minimum) inner diameter of the first tube connected to the discharge port 8, the (minimum) inner diameter of the second tube, It can be controlled by selecting a die shape or the like for deforming the solid material. For example, by connecting a first tubular body having a minimum inner diameter exceeding 20 μm to the discharge port 8, a solid material having a maximum thickness (maximum diameter) exceeding 20 μm can be obtained.

  In the production method of the present invention, a solid can be continuously obtained by applying the above force continuously to the dispersion. That is, not a batch production method but a continuous production method. For example, the dispersion may be continuously supplied to the chamber 1 shown in FIGS. 1 to 4 and the solid matter may be continuously discharged from the chamber 1.

  Further, for example, the dispersion may be continuously supplied to the second tube used in Method C, and the solid material may be continuously discharged from the second tube.

  In this case, if the chamber or tube has a structure other than the supply port and the discharge port, there is no opening through which substances enter and exit, and the mass of the dispersion supplied to the chamber or tube and the chamber or tube are discharged from the chamber or tube. The mass of the PTFE-containing solid material can be made substantially the same. In such an initial stage of continuous production, liquid may be discharged from the chamber or the like, probably because sufficient force is not applied to the dispersion. However, once the initial stage is reached and a stable state in which a sufficient force is applied to the dispersion is achieved, the entire amount of the dispersion is then changed to a PTFE-containing solid. Thereafter, except for a small amount of water lost by evaporation from the discharged PTFE-containing solid material, the supplied dispersion and the obtained PTFE-containing solid material have the same mass. As described above, according to the production method of the present invention, substantially all of the liquid phase raw material (dispersion) containing the solid content can be changed to a solid phase single phase intermediate (PTFE-containing solid). it can.

  The content of PTFE particles in the dispersion is not particularly limited, but in order to obtain a solid having an excellent balance between self-shape retention and deformability, for example, the lower limit may be 40% by mass or more, and 40% by mass. %, More preferably more than 45% by mass, and even more preferably in the order of 50% by mass or more and 55% by mass or more. Moreover, the upper limit of the content rate of the PTFE particles in the dispersion may be, for example, 70% by mass or less, and more preferably 65% by mass or less, for the same reason as described above.

  Although depending on the method and conditions for applying force to the dispersion, basically, as the content of PTFE particles in the dispersion increases, the self-shape retention of the resulting solid improves, and the content of PTFE particles As the value becomes smaller, the deformability of the obtained solid matter tends to be improved.

  The average particle diameter of the PTFE particles is usually in the range of 0.1 μm to 40 μm, and preferably in the range of 0.2 μm to 1 μm.

  The content of the surfactant in the dispersion is not particularly limited, but is preferably in the range of 0.01% by mass to 15% by mass in order to obtain a solid having an excellent balance between self-shape retention and deformability. More preferably in the order of 0.1 mass% to 10 mass%, 1 mass% to 9 mass%, 1.5 mass% to 9 mass%, and 2 mass% to 7 mass%. If the content of the surfactant is within a preferable range, it becomes easy to obtain a PTFE-containing solid while suppressing the separation of the PTFE phase and the aqueous phase.

  The type of the surfactant is not particularly limited as long as it is nonionic, and for example, polyoxyethylene alkyl ether, polyoxyethylene derivative, glycerin fatty acid ester and the like may be used. It is preferable to use a surfactant that decomposes in a temperature range from 100 ° C. to the melting point of PTFE. In this case, the surfactant is decomposed when the obtained solid is fired, and a PTFE molded body formed by firing. The amount of the surfactant remaining therein can be reduced.

  A commercially available PTFE dispersion may be used as the dispersion. Examples of commercially available PTFE dispersions include AD series such as AD938, AD911, AD912, AD1, AD639, and AD936 manufactured by Asahi Glass Co., Ltd. (former Asahi Glass Fluoropolymers Co., Ltd.), D1, D2, and D3 manufactured by Daikin Industries, Ltd. A series may be used. These commercially available PTFE dispersions usually contain a nonionic surfactant.

  The dispersion may contain substances other than PTFE particles, water, and a surfactant.

  The method for producing a PTFE molded product of the present invention includes a step (drying step) of reducing the amount of water contained in the PTFE-containing solid obtained by the above-described method. The specific method of a drying process is not specifically limited, For example, the obtained solid substance should just be heated up to the temperature of 50 to 200 degreeC, and should be hold | maintained about 1 minute-60 minutes.

  Moreover, in the manufacturing method of the molded object of this invention, the solid substance which passed through the drying process may be further baked (baking process). The specific method of a baking process is not specifically limited, For example, the solid substance which passed through the drying process is accommodated in an electric furnace, and the temperature more than melting | fusing point of PTFE (about 327 to 400 degreeC, Preferably it is 360 to 380 degreeC). C.) and hold for about 1 to 60 minutes. In addition, what is necessary is just to set the time of drying and baking suitably according to the thickness etc. of a solid substance.

  The PTFE molded body formed through the drying step or the drying and firing steps may be used as a product as it is, and steps such as rolling and stretching may be further added as necessary.

  According to the method for producing a molded body of the present invention, the degree of freedom of the shape of the molded body to be formed can be increased. For example, a molded body having a minimum thickness of 20 μm or more, exceeding 20 μm, or 1 mm or more, or 2 cm or more can be formed depending on the solid production conditions. Conversely, it is possible to form a molded body having a maximum thickness of 5 cm or less.

  Moreover, in the manufacturing method of the molded object of this invention, a PTFE molded object can be formed continuously and it can be set as the manufacturing method which is more excellent in productivity compared with the conventional manufacturing method which is based on a batch production method.

  In addition, although it can be said that the PTFE containing solid substance obtained by this invention is an intermediate product formed in the manufacturing process of a PTFE molded object, it is also possible to distribute | circulate in the state of a solid substance.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the examples shown below.

(Example 1)
In Example 1, AD938 manufactured by Asahi Glass Co., Ltd. (PTFE particle content: 60 mass%, PTFE particle average particle size: 0.3 μm, surfactant content: 3 mass%) is a commercially available PTFE dispersion. 1 was used to form a sheet-like solid using the chamber 1 shown in FIG. 1, and the formed solid was dried and fired to produce a PTFE sheet. The type of surfactant contained in AD938 is a nonionic surfactant, and its cloud point is about 60 ° C.

The volume of the internal space 2 of the chamber 1 (the internal volume of the chamber 1) was 200 cm ^3, and a pair of nozzles 3a and 3b having circular injection ports (0.25 mmφ) were arranged in the chamber. The nozzle 3a, 3b was arrange | positioned so that the injection direction 4a, 4b of each nozzle may cross | intersect in the part in which the injection opening in the front-end | tip of a nozzle was formed. A tube body (first tube body) having an inner diameter of 10 mm and a length of 1000 mm having a circular cross section was connected to the discharge port 8 (circular, diameter 10 mm).

  The dispersion liquid (liquid temperature 25 ° C.) was supplied to the chamber 1 and the dispersion liquid was ejected from the nozzles 3a and 3b. The supply amount of the dispersion was about 3 L / min, and the injection pressure of the dispersion was 180 MPa. No particular heating was performed on the chamber 1 and the dispersion.

  Ten seconds after the start of injection, string-like (cylindrical) PTFE-containing solid matter is discharged from the tip of the tube, and the discharged solid matter contains water and a surfactant and is not supported by the support. It was possible to maintain its own shape.

  When the temperature of the solid matter discharged from the tip of the tube body was measured, it was stabilized at about 70 ° C. after about 30 seconds from the start of injection. It is considered that the temperature of the dispersion liquid in which the solid matter is formed in the chamber 1 is equal to or higher than this temperature. In other words, in this experiment, the PTFE particles are bound to each other in the temperature range of 70 ° C. or higher as the temperature of the dispersion liquid. It is thought that it was done.

  Subsequently, a T die (die width 320 μm) for forming a solid material into a sheet shape is connected to the end surface of the tubular body opposite to the end surface connected to the discharge port 8. The dispersion was sprayed from 3a and 3b. The dispersion liquid is continuously supplied to the chamber 1, and an aluminum foil is disposed under the discharge port of the T die as a support for continuously receiving solid matter discharged from the die. It was moved at a speed of / min.

  A few seconds after the start of spraying, a solid material (width 5 cm, thickness 500 μm) formed into a sheet shape is continuously discharged from the die onto the aluminum foil, and the discharged solid material contains water and a surfactant. It was encapsulated and could hold its own shape without the aluminum foil as a support. Subsequently, the obtained solid was dried at 90 ° C. for 15 minutes and then baked at 370 ° C. for 10 minutes. As a result, a PTFE sheet having a uniform thickness without occurrence of cracks (thickness 350 μm) was gotten.

  The same experiment was conducted by changing the nozzle orifice diameter in the range of 0.05 mm to 0.5 mm, the dispersion injection pressure in the range of 30 MPa to 300 MPa, and the dispersion supply amount in the range of 0.3 L / min to 30 L / min. The same PTFE sheet could be produced by changing each within the range.

(Example 2)
In Example 2, AD938 manufactured by Asahi Glass Co., Ltd. was used as the dispersion, a string-like solid was formed using the chamber 1 shown in FIG. 4, and the formed solid was dried and fired to form a string-like PTFE molded body. Was made.

The internal volume of the chamber 1 was 200 cm ^3, and the interval d between the slit-like narrow portions was adjusted to 0.1 mm by adjusting the positions of the cores 12a and 12b. A tube body (first tube body) having an inner diameter of 1.6 mm and a length of 200 mm having a circular cross section was connected to the discharge port 8 (circular, diameter: 10 mm).

  The above dispersion liquid (liquid temperature: 25 ° C.) pressurized to 245 MPa was supplied to such a chamber 1. The supply amount of the dispersion was about 0.5 L / min. No particular heating was performed on the chamber 1 and the dispersion.

  Ten seconds after starting the supply of the dispersion, the string-like (columnar) PTFE-containing solid is discharged from the tip of the tube, and the discharged solid contains water and a surfactant and is supported. It was possible to maintain its own shape without support by the body.

  When the temperature of the solid matter discharged from the tip of the tube was measured, it was stabilized at about 80 ° C. after about 20 seconds from the start of supply.

  Subsequently, the obtained solid was dried at 90 ° C. for 30 minutes and then baked at 370 ° C. for 20 minutes. As a result, a string-like (columnar) PTFE molded body (diameter 1 having no cracks) was generated. 0.7 mm) was obtained.

  The same experiment was conducted by changing the supply pressure of the dispersion liquid in the range of 100 MPa to 300 MPa and the interval d in the range of 1 μm to 1 mm, and the same PTFE molded body could be produced.

(Example 3)
In Example 3, AD938 manufactured by Asahi Glass Co., Ltd. was used for the dispersion, and a string-like PTFE solid was formed using the tube (second tube) 21 shown in FIG. The tube body 21 has an L-shaped bent portion 23 in the vicinity of one end portion 22 as a barrier that hinders the flow of the dispersion liquid. The inner diameter of the tube body 21 was 10 mm, the length was 200 mm, and the position of the bent portion 23 was 30 mm from one end 22 of the tube body 21.

  Such a tube body 21 and a nozzle 25 (having a circular injection port (0.15 mmφ)) arranged at the end of the dispersion liquid supply path 26 are disposed on the central axis of the tube body 21. Then, after arranging each other so that the distance between the other end 24 of the tube body 21 and the nozzle 25 was 5 mm (see FIG. 5), the dispersion liquid was sprayed from the nozzle 25 into the tube body 21. The amount of the dispersion supplied to the nozzle 25 was about 0.5 L / min, the temperature of the dispersion was 25 ° C., and the spray pressure of the dispersion was 160 MPa. The tube body 21 and the dispersion liquid were not particularly heated.

  A few seconds after the start of injection, the string-like PTFE-containing solid matter is discharged from the end 22 of the tube body 21, and the discharged solid matter contains water and a surfactant and is not supported by the support itself. It was possible to keep the shape of.

  When the temperature of the solid matter discharged from the end of the tube was measured, it was stabilized at about 60 ° C. after about 40 seconds had elapsed since the start of injection.

  A similar experiment was performed by changing the spray pressure of the dispersion in the range of 200 MPa to 240 MPa. As a result, a similar PTFE-containing solid material could be obtained.

  The same experiment was conducted by changing the content of PTFE particles in the dispersion, and the same PTFE-containing solid matter could be obtained even when the content was 54 mass% and 48 mass%. .

Example 4
In Example 4, AD938 manufactured by Asahi Glass Co., Ltd. was used as the dispersion, and a string-like PTFE solid was formed using the tube (second tube) 31 shown in FIG. The tubular body 31 has a T-shaped bent portion 27 in the vicinity of one end portion 22 as a barrier that hinders the flow of the dispersion liquid. The inner diameter of the tube 31 is 10 mm, the length (the length from one end 22 to the other end 24) is 200 mm, and the position of the bent portion 27 is 30 mm from the one end 22 of the tube 31. .

  Such a pipe body 31 and a nozzle 25 (having a circular injection port (0.15 mmφ)) arranged at the end of the dispersion liquid supply path 26 are located on the central axis of the pipe body 31. Then, after arranging each other so that the distance between the other end 24 of the tube 31 and the nozzle 25 was 5 mm (see FIG. 6), the dispersion liquid was sprayed from the nozzle 25 into the tube 31. The amount of the dispersion supplied to the nozzle 25 was about 0.5 L / min, the temperature of the dispersion was 25 ° C., and the spray pressure of the dispersion was 240 MPa. The tube body 31 and the dispersion liquid were not particularly heated.

  A few seconds after the start of injection, the string-like PTFE-containing solid matter is discharged from the end portion 22 of the tubular body 31, and the discharged solid matter contains water and a surfactant, and is not supported by the support itself. It was possible to keep the shape of. At this time, the string-like PTFE-containing solid matter was not discharged from the end portion 28 that constitutes the “T-shaped” open end portion together with the end portion 22. When the above injection was performed a plurality of times, in each case, the string-like PTFE-containing solid matter was discharged only from either one of the end 22 or the end 28.

  When the temperature of the solid matter discharged from the end of the tube body was measured, it was stabilized at about 80 ° C. after about 20 seconds had elapsed from the start of injection.

  When the same experiment was conducted with the dispersion spraying pressure set to 200 MPa, a similar PTFE-containing solid material could be obtained.

  The same experiment was conducted by changing the content of PTFE particles in the dispersion, and the same PTFE-containing solid matter could be obtained even when the content was 54 mass% and 48 mass%. .

(Example 5)
In Example 5, AD938 manufactured by Asahi Glass Co., Ltd. was used as the dispersion, and a string-like PTFE solid was formed using a tube (second tube) 41 shown in FIG. The tube body 41 has a constricted portion 29 having an inner diameter changed at a central portion in the length direction as a barrier that hinders the flow of the dispersion liquid. The length of the tube 41 was 400 mm, the inner diameter in the range of 200 mm from one end 22 was 2 mm, and the inner diameter in the range of 200 nm from the other end was 10 mm. That is, in the tubular body 41, the inner diameter changes from 10 mm to 2 mm at the narrowed portion 29.

  Such a pipe body 41 and a nozzle 25 (having a circular injection port (0.15 mmφ)) arranged at the end of the dispersion liquid supply path 26 are arranged on the central axis of the pipe body 41. Then, after arranging them so that the distance between the end portion 24 of the tube body 41 having an inner diameter of 10 mm and the nozzle 25 becomes 5 mm (see FIG. 7), the dispersion liquid is sprayed from the nozzle 25 into the tube body 41. It was. The amount of the dispersion supplied to the nozzle 25 was about 0.5 L / min, the temperature of the dispersion was 25 ° C., and the spray pressure of the dispersion was 240 MPa. No particular heating was performed on the tube body 41 and the dispersion liquid.

  Several seconds after the start of injection, the string-like PTFE-containing solid matter is discharged from the end portion 22 of the tube body 41. The discharged solid matter contains water and a surfactant and is not supported by the support itself. It was possible to keep the shape of.

  When the temperature of the solid matter discharged from the end of the tube body was measured, it was stabilized at about 80 ° C. after about 20 seconds had elapsed from the start of injection.

  When the same experiment was conducted with the dispersion spraying pressure set to 200 MPa, a similar PTFE-containing solid material could be obtained.

  The same experiment was conducted by changing the content of PTFE particles in the dispersion, and the same PTFE-containing solid matter could be obtained even when the content was 54 mass% and 48 mass%. .

(Example 6)
The string-like and sheet-like solids obtained in Examples 1 to 5 were left standing in water, respectively, and after 365 days had passed, the solids were not put in water. The shape of was retained.

  The string-like and sheet-like solids obtained in Examples 1 to 5 were each dried at 90 ° C. for 15 minutes, and then placed on a 1 μm mesh sieve to vibrate the sieve. This object was not obtained.

(Example 7)
In Example 7, AD938 manufactured by Asahi Glass Co., Ltd. was used for the dispersion, and a string-like PTFE solid was formed using a U-shaped tube (second tube). The tube body has a bent portion in the middle between one end portion and the other end portion as a barrier that prevents the flow of the dispersion liquid. The inner diameter of the tube was 8 mm and the length was 200 mm.

  Such a tube body and a nozzle (having a circular injection port (0.15 mmφ)) disposed at the end of the dispersion supply path are arranged on the central axis of the tube body. After arranging each other so that the distance between one end and the nozzle was 5 mm, the dispersion liquid was sprayed from the nozzle into the tube.

  The amount of the dispersion supplied to the nozzle was about 0.5 L / min, the temperature of the dispersion was 25 ° C., and the injection pressure of the dispersion was 100 MPa and 150 MPa. No particular heating was performed on the tube and the dispersion.

  A few seconds after the start of injection, the string-like PTFE-containing solid matter is discharged from the other end of the tube, and the discharged solid matter contains water and a surfactant and is not supported by the support itself. It was possible to keep the shape of.

  When the temperature of the solid matter discharged from the end of the tube was measured, it was stabilized at about 60 ° C. after about 40 seconds had elapsed since the start of injection.

  Next, a tensile test is performed on the string-like solid matter discharged from the end of the tubular body, and the SS curve (stress-strain curve) of the solid matter is measured. Strength (maximum tensile strength) and maximum elongation were evaluated. The SS curve of the solid was measured using an autograph AG-1 manufactured by Shimadzu Corporation with a tensile force of 1 N, a tensile speed of 100 mm / min, and a distance between chucks of 20 mm. The direction in which the solid is pulled in the test is the MD direction of the solid. The SS curves were measured for solids obtained under both injection pressure conditions of 100 MPa and 150 MPa, respectively.

  The measured SS curve is shown in FIG.

  Separately from the measurement of the SS curve, the string-like solid matter discharged from the end of the tube is dried at 80 ° C. for 1 hour to obtain a molded product, and a tensile test is performed on the obtained molded product. Then, the SS curve of the molded body was measured, and its maximum strength and maximum elongation were evaluated. The SS curve of the compact was measured in the same manner as the SS curve of the solid.

  The measured SS curve is shown in FIG. 8 together with the solid SS curve, and the maximum strength, the elongation at the maximum strength, and the maximum elongation in each sample are summarized in Table 1 below.

  As shown in FIG. 8 and Table 1, both the solid before drying and the molded article after drying showed that the higher the injection pressure, the greater the maximum strength and the lower the elongation at the maximum strength and the maximum elongation. . Further, it was found that there was no yield point in the solid before drying, but there was a yield point in the molded product after drying. From these results, it was found that PTFE secondary particles were not obtained by drying the solid, but a PTFE molded product having higher tensile strength and elasticity than the solid state could be formed.

(Example 8)
In Example 8, the whole surfactant contained in the dispersion was added to the dispersion of PTFE particles containing the nonionic surfactant by adding another nonionic surfactant having a cloud point different from that of the surfactant. A plurality of dispersion liquid samples with different cloud points T1 were prepared, and the degree of temperature rise of the dispersion liquid with respect to the cloud point T1 when each dispersion liquid was ejected from a nozzle to form a solid was obtained. The relationship with the tensile strength of the solid was evaluated.

  As the dispersion, D2CE manufactured by Daikin Industries, Ltd. (PTFE particle content: 60 mass%, PTFE particle average particle size: 0.3 μm, surfactant content: 5 mass%), which is a commercially available PTFE dispersion, was used. . The type of surfactant contained in D2CE is a nonionic surfactant polyoxyethylene alkyl ether, and its cloud point is 70.0 ° C.

  The surfactants shown in Table 2 below were further added to D2CE, and five types of dispersion samples (samples) having different cloud points T1 as a whole surfactant were included, including a sample (sample 5) in which nothing was added. 1-5) were produced. The surfactants shown in Table 2 are all polyoxyethylene alkyl ethers.

  The cloud point in each dispersion liquid sample was a temperature at which the viscosity of the dispersion liquid was measured while the temperature of each sample was raised, and the measured viscosity dropped rapidly. In this evaluation method, the viscosity of an aqueous solution containing a nonionic surfactant generally increases as the liquid temperature increases in a temperature range below the cloud point of the surfactant contained in the solution, and rapidly decreases at the cloud point. Based on showing behavior. A tuning fork type vibration viscometer SV-10 (manufactured by A & D) was used to measure the viscosity of each sample.

  A string-like PTFE-containing solid was obtained in the same manner as in Example 3 using each of the dispersion samples thus prepared. When forming the PTFE-containing solid material, the spray pressure of the dispersion was set to 100 MPa, 150 MPa, and 180 MPa.

  When the temperature T2 of the solid matter discharged from the end 22 of the tube body 21 was measured, after about 30 seconds had elapsed from the start of injection, it was 52.1 ° C. (injection pressure 100 MPa) regardless of the type of the dispersion sample. Stable at 65.3 ° C. (injection pressure 150 MPa) and 77.2 ° C. (injection pressure 180 MPa), respectively. The temperature of the dispersion liquid in which the solid matter is formed in the tube body 21 is 52.1 ° C. or more (injection pressure 100 MPa), 65.3 ° C. or more (injection pressure 150 MPa), and 77.2 ° C. or more (injection pressure 180 MPa). It is believed that there is. That is, in this experiment, PTFE was used in the temperature ranges of 52.1 ° C. or higher (injection pressure 100 MPa), 65.3 ° C. or higher (injection pressure 150 MPa), and 77.2 ° C. or higher (injection pressure 180 MPa). It is thought that the particles were bound together.

  Next, the SS curve of the obtained solid was measured in the same manner as in Example 7, and the maximum strength and the maximum elongation were evaluated. The maximum strength and maximum elongation in each sample are shown in the following table together with the temperature difference Δ (° C.) between the cloud point T1 of each dispersion sample and the temperature T2 of the solid, and the viscosity of each dispersion sample at the temperature T2. Shown in 3-5. Table 3 shows the results when the dispersion injection pressure is 100 MPa, Table 4 shows the results when the dispersion injection pressure is 150 MPa, and Table 5 shows the results when the dispersion injection pressure is 180 MPa. In addition, the said viscosity was measured using the tuning fork type | formula vibration type | formula viscometer which raised each dispersion liquid sample to temperature T2 separately from formation of the said solid substance. However, when the spray pressure of the dispersion liquid was 180 MPa, the temperature T2 of the solids obtained in the four samples exceeded the cloud point T1, and thus the viscosity measurement was omitted.

As shown to Tables 3-5, it turned out that the temperature T2 of the solid substance obtained shows the tendency to increase with the increase in the injection pressure of a dispersion liquid. This is probably because the heat generated by the collision between the PTFE particles increased due to the increase in the injection pressure. Moreover, the temperature difference (DELTA) (= T1-T2) showed the tendency for the maximum intensity | strength of the obtained solid to increase in order of 10 degrees C or less, 5 degrees C or less, and 3 degrees C or less. When the temperature difference Δ is negative, that is, when the temperature of the dispersion in which the solid is formed is equal to or higher than the cloud point T1, a solid having a good maximum strength of 1.7 (N / mm ² ) or higher is obtained. It turns out that it is obtained.

  When the dispersion injection pressure was 150 MPa, the maximum strength of the obtained solids tended to increase as the viscosity of each dispersion sample at temperature T2 increased. For example, when the temperature difference Δ is in the range of about 2 to 15 ° C., the increase in the viscosity of the dispersion accompanying the temperature rise may greatly affect the structure of the obtained solid.

  In addition, there is a difference in the maximum strength of the obtained solids between Samples 1 and 3 having substantially the same cloud point T1, and this difference is due to the HLB (hydrophilic / hydrophobic balance) in the contained surfactant. ) And other characteristics.

(Comparative example)
In the comparative example, AD938 manufactured by Asahi Glass Co., Ltd. was used as the dispersion, and an attempt was made to produce a PTFE sheet having a thickness of 300 μm by a casting method.

  The dispersion was applied to the surface of the aluminum substrate (application thickness: 600 μm), and the whole was dried at 120 ° C. for 15 minutes and then baked at 380 ° C. for 10 minutes. As a result, sheet-like PTFE was formed on the substrate. The formed PTFE had innumerable cracks and could not be peeled off from the substrate in the form of a sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the novel manufacturing method of a PTFE containing solid substance and a PTFE molded object which use the dispersion liquid of PTFE particle | grains as a starting material can be provided. According to the production method of the present invention, a PTFE solid and a PTFE molded product can be produced with high productivity, and the degree of freedom of the shape of the obtained solid and molded product can be increased.

It is a schematic diagram which shows an example of the chamber which can be used for the manufacturing method of the PTFE containing solid substance of this invention. It is a schematic diagram which shows another example of the chamber which can be used for the manufacturing method of the PTFE containing solid substance of this invention. It is a schematic diagram which shows another example of the chamber which can be used for the manufacturing method of the PTFE containing solid substance of this invention. It is a schematic diagram which shows another example of the chamber which can be used for the manufacturing method of the PTFE containing solid substance of this invention. It is a schematic diagram for demonstrating the formation method of the 2nd tubular body used for the Example, and the PTFE containing solid substance by the said 2nd tubular body. It is a schematic diagram for demonstrating the formation method of the 2nd tubular body used for the Example, and the PTFE containing solid substance by the said 2nd tubular body. It is a schematic diagram for demonstrating the formation method of the 2nd tubular body used for the Example, and the PTFE containing solid substance by the said 2nd tubular body. It is a figure which shows the SS (stress-strain) curve of the PTFE containing solid substance measured in Example 7, and a molded object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Internal space 3, 3a, 3b Nozzle 4, 4a, 4b Injection direction 5 Structure 6, 6a, 6b Supply path 7 Supply port 8 Discharge port 9 Mixing valve 10 Sphere 11 Outer body 12a, 12b Core 13a, 13b Upper surface 14 Discharge path 15 Air gap 21 Tubular body (second tubular body)
22 End portion 23 Bending portion 24 End portion 25 Nozzle 26 Supply path 27 Bending portion 28 End portion 29 Constriction portion 31 Tubular body (second tubular body)
41 Tube (second tube)

Claims (19)

  A mechanical force is applied to a dispersion of polytetrafluoroethylene particles containing polytetrafluoroethylene particles, a nonionic surfactant having a cloud point of T1 ° C., and water as a dispersion medium, and the particles are bonded together. The temperature of the dispersion liquid is increased by the heat generated during the collision, and the particles are bound to each other in a temperature range equal to or higher than the temperature of the dispersion liquid (T1-30) ° C., and the water and A method for producing a solid containing polytetrafluoroethylene, which obtains a solid containing the surfactant.   The method for producing a polytetrafluoroethylene-containing solid material according to claim 1, wherein the particles are bound to each other in a temperature range of (T1-10) ° C or higher as the temperature of the dispersion liquid.   The method for producing a polytetrafluoroethylene-containing solid material according to claim 1, wherein the particles are bound to each other in a temperature range of T1 ° C or higher as the temperature of the dispersion liquid.   The method for producing a polytetrafluoroethylene-containing solid material according to claim 1, wherein the dispersion is supplied to a chamber and the force is applied in the chamber.   The manufacturing method of the polytetrafluoroethylene containing solid substance of Claim 4 which applies the said force by spraying the said dispersion liquid toward the inner wall of the said chamber, or the object in the said chamber.   The manufacturing method of the polytetrafluoroethylene containing solid substance of Claim 5 which injects the said dispersion liquid from a nozzle.   The manufacturing method of the polytetrafluoroethylene containing solid substance of Claim 4 which applies the said force by allowing the said dispersion liquid to pass through the constriction part provided in the said chamber.   The method for producing a polytetrafluoroethylene-containing solid material according to claim 1, wherein the force is applied by bringing the dispersion into contact with a barrier disposed in a flow path of the dispersion to prevent the flow of the dispersion. .   The method for producing a polytetrafluoroethylene-containing solid according to claim 8, wherein the dispersion is supplied to a tube having the barrier and the force is applied.   The method for producing a polytetrafluoroethylene-containing solid material according to claim 9, wherein the barrier is a bent portion or a narrowed portion of the tubular body.   The method for producing a solid material containing polytetrafluoroethylene according to claim 1, wherein the dispersion is supplied to a tubular body having a bent portion or a narrowed portion, and the force is applied to the bent portion or the narrowed portion.   The method for producing a polytetrafluoroethylene-containing solid according to claim 9 or 11, wherein the dispersion is sprayed from a nozzle and supplied to the tube.   The method for producing a solid material containing polytetrafluoroethylene according to claim 1, wherein the solid material having substantially the same mass as the dispersion liquid to which the force is applied is obtained.   2. The polytetrafluoro of claim 1, wherein the solid matter is formed by binding the particles to such an extent that the imparted shape is maintained, and encapsulating the water to some extent such that the shape is deformable. A method for producing an ethylene-containing solid.   The method for producing a polytetrafluoroethylene-containing solid according to claim 1, wherein the particles are bound to such an extent that the solid does not disperse in water.   The method for producing a polytetrafluoroethylene-containing solid according to claim 1, wherein the solid is bound to such an extent that re-particulation does not occur due to a decrease in the amount of water contained therein.   The method for producing a polytetrafluoroethylene-containing solid according to claim 1, further comprising a step of deforming the solid. Obtaining a polytetrafluoroethylene-containing solid by the method of claim 1;
And a step of reducing the amount of the water contained in the obtained solid matter.   The method for producing a polytetrafluoroethylene molded body according to claim 18, further comprising a step of heating the solid material to a temperature equal to or higher than a melting point of polytetrafluoroethylene and baking the solid.

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