JP3970214B2 - Method for producing tetrafluoroethylene resin laminated sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tetrafluoroethylene resin sheet excellent in chemical resistance, heat resistance, weather resistance, flex resistance, tear resistance, antifouling property and uniformity, and in particular, a corrosion resistant packing member, food / chemical It is related with the tetrafluoroethylene resin sheet excellent in the uniformity suitable for nonadhesive conveyance belt members, such as a non-adhesive conveyance belt member, a machine work, a structural material member, etc.
[0002]
[Prior art]
Fluorocarbon resins, especially tetrafluoroethylene resin (hereinafter abbreviated as PTFE resin), are excellent in chemical resistance, heat resistance, weather resistance, electrical properties, antifouling properties, non-adhesiveness, etc. Used in the field.
[0003]
However, PTFE resin, unlike molten resins such as polyethylene and polypropylene, has a high viscosity even in a molten state and is difficult to be extruded or injection molded. This is a material that is difficult to process because a method such as casting (casting) cannot be applied. Furthermore, although PTFE resin is excellent in chemical resistance, heat resistance, weather resistance, electrical properties, antifouling properties, non-adhesiveness, etc., it has physical properties such as flex resistance, tear resistance, and tensile strength. Inferior, it was difficult to use as a structural material.
[0004]
By the way, a conventional PTFE resin film production method is generally performed by a skiving method in which PTFE powder is formed into a cylindrical shape and fired, and this is cut into a so-called Katsura peel to form a film. Furthermore, a manufacturing method is also proposed in which an organic solvent-soluble fluororesin thin film is formed on a substrate, a PTFE resin aqueous dispersion is applied to the surface, dried, baked, and then immersed in an organic solvent to separate the PTFE resin film. (See Patent Document 1).
[0005]
In addition, in order to improve physical properties, a process of coating a PTFE resin emulsion on glass cloth or aramid woven fabric by dipping or coating and baking at a temperature of about 370 ° C. is repeated a plurality of times to obtain a desired thickness. In general, a method of forming a film is used. This is because the PTFE resin has poor adhesiveness, and a fixed film cannot be formed by a normal means such as heat-bonding a PTFE resin film to a glass cloth.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-278927 [0007]
[Problems to be solved by the invention]
However, in the film and sheet manufacturing method as described above, physical strength is not taken into consideration, so that it is still inferior in strength as a structural material, and a cloth base material such as glass cloth is PTFE. In the method of coating the resin emulsion, since it is repeatedly wetted and heated by a solvent, there is a problem that the heat-resistant organic fiber undergoes so-called wet heat deterioration and performance is deteriorated, and sufficient strength is not obtained.
[0008]
Therefore, the present invention provides a PTFE resin laminated sheet having characteristics suitable as a structural material such as flex resistance and tear resistance by one-time pressure bonding and firing without repeating the impregnation and firing steps, and having a desired thickness. It aims at providing the manufacturing method of.
[0009]
[Means for Solving the Problems]
The method for producing a PTFE resin laminated sheet of the present invention is such that paste-like PTFE resin fine particles are extruded and pressed to form a PTFE resin green tape, and the PTFE resin green tape and a wire mesh are bonded together and pressed. And then firing.
[0010]
According to the method for producing a PTFE resin laminate sheet of the present invention, PTFE resin fine particles are extruded, pressed into a PTFE resin unfired tape of the desired thickness, and then bonded to a wire mesh and baked. It is not necessary to repeat the same process as in the conventional method of impregnating and baking glass cloth multiple times in PTFE resin emulsion, and a PTFE resin laminated sheet having a desired thickness can be produced in a single process. is there.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an extruder for producing a PTFE resin raw material bar which is a raw material of the PTFE resin green tape of the present invention. The raw material PTFE resin fine particles are mixed in a paste form together with a solvent and filled in an extruder. The PTFE resin raw material paste 10 is pressurized by a hydraulic device 11, heated by a heater 13 provided at the extrusion port 12, and extruded as a PTFE resin raw material bar 14. This raw material bar 14 is wound up by a winder 15 and sent to the next step shown in FIG.
[0012]
FIG. 2 shows a PTFE resin green tape manufacturing apparatus of the present invention. The PTFE resin raw material bar 14 manufactured by the extruder is immersed in the hot water layer 21, and is then introduced into the calender roll 23 by the guide 22, and is rolled and pressed into a sheet by the calender roll 23. Here, by adjusting the linear pressure of the calendar roll 23 and the roll gap, the thickness of the PTFE resin sheet to be press-molded can be arbitrarily adjusted. Further, a plurality of calendar rolls 23 may be provided as necessary, and press molding may be performed stepwise. The press-molded raw material is introduced into the extraction tank 25 via a plurality of guide rollers 24, and the solvent contained in the PTFE resin is removed. Subsequently, after being sent to the dryer 26, it is wound up by a winder 27. Furthermore, the PTFE resin non-fired tape 29 having a target width is obtained by cutting with a slitter 28 as necessary.
[0013]
In addition, the manufacturing method of a PTFE resin unbaking tape is not limited to the method according to FIG. 1 and FIG. 2 described above, and is manufactured in a tape (sheet) shape having a thickness of about 20 μm to 2 mm and a width of about 1 to 100 cm. If it is a thing, PTFE resin microparticles | fine-particles and an extruder can be selected suitably, for example .
[0014]
FIG. 3 shows an apparatus for producing a PTFE resin laminated sheet according to claim 1 of the present invention. The above-mentioned PTFE resin unfired tape 29 is fed to the calendar roll 31 in a state of being bonded to the wire mesh 30, and is temporarily formed by pressing. Then, it introduce | transduces into the baking machine 32, is baked, and the PTFE resin laminated sheet 33 by which the metal mesh was laminated | stacked on one side is obtained.
[0015]
In the method for producing a PTFE resin laminated sheet of the present invention, as shown in FIG. 4, PTFE resin unfired tape is bonded to both sides of a wire mesh, press-molded, and then fired. According to such an embodiment, a PTFE resin laminated sheet in which a wire mesh is embedded in PTFE resin can be manufactured. Moreover, as a metal mesh laminated | stacked in PTFE resin, what consists of stainless steel, iron, copper, brass etc. is mentioned. In addition, it is not particularly limited to a wire mesh, and a material such as a metal, ceramic, organic polymer, etc., as long as it is a porous or mesh sheet such as glass cloth, aramid cloth, metal fiber woven fabric or nonwoven fabric, punching metal, expanded metal, etc. Anything can be applied without being limited to.
[0016]
In the method for producing a PTFE resin laminated sheet according to the present invention, it is preferable that the PTFE resin unfired tape to be bonded to the wire mesh is a laminate of a plurality of tapes. An example of an apparatus for producing such a PTFE resin laminated sheet is shown in FIG. According to such a manufacturing apparatus, it is possible to supply a metal mesh and a plurality of PTFE resin unsintered tapes on both sides thereof. Subsequently, these are press-molded with a calender roll, and a plurality of layers of PTFE resin unfired tape are bonded to both sides of the wire mesh and fired to obtain a PTFE resin laminated sheet.
[0017]
In general, PTFE resin green tape has many fine holes. However, by laminating and pressing a plurality of sheets as described above, such fine holes are blocked by a plurality of PTFE resin sheets. And airtightness is improved. Moreover, the laminated PTFE resin sheet having a desired thickness can be obtained in a single step by using a plurality of PTFE resin green tapes.
[0018]
In the method for producing a PTFE resin laminated sheet of the present invention, various PTFE resin fine particles can be used, but PTFE resin fine particles produced by an emulsion polymerization method are particularly preferable. The PTFE resin fine particles are excellent in plasticity, and the particles are easily bonded to each other by press molding after mixing and extrusion molding, and a dense PTFE resin sheet with few defects (for example, holes) can be produced.
[0019]
As described above, according to the method for producing a PTFE resin laminated sheet of the present invention, PTFE resin fine particles are mixed with a solvent and extruded, and this is press-molded into a PTFE green tape having a desired thickness. Since it is bonded and bonded and fired, there is no need to repeat the same process as in the conventional method of impregnating and baking glass cloth multiple times in PTFE resin emulsion, and a PTFE resin laminated sheet having a desired thickness is processed once. It can be manufactured with.
[0020]
【Example】
Examples of the present invention will be described in detail below. Note that the present invention is not limited to this. First, the PTFE resin non-baked tape used for manufacture of the PTFE resin laminated sheet of this invention was produced as follows.
[0021]
25% of a solvent (trade name: Isopar G, manufactured by ExxonMobil Corp.) was added to the molding powder for paste extrusion (PTFE resin fine particles) as an extrusion aid and mixed under conditions of 10 rpm / 10 min and uniformly moistened. Subsequently, this mixture was compressed at 1 MPa to be preformed and extruded into a round string shape by a ram extruder at a heater temperature of 50 to 60 ° C. and a speed of 5 mm / min. The extrudate was passed through a calender roll several times and rolled into a 0.6 mm (0.2 mm) tape. The extrusion aid contained in this tape was removed in an extraction tank, dried, and cut into predetermined dimensions.
[0022]
[Example 1]
The PTFE resin green tape having a thickness of 0.6 mm was prepared by the above method, and the upper and lower surfaces of the wire mesh (wire diameter: 0.3 mmφ, 36 mesh) were sandwiched between the PTFE resin green tape as shown in FIG. Then, it was passed through a calender roll and pressed under the conditions of a linear pressure of 140 kg / cm, a roll gap of 400 μm, and a temperature of 30 ° C. Subsequently, it was baked at 380 ° C. for 10 minutes to obtain a PTFE resin laminated sheet of the present invention having a thickness of 500 μm embedded with a wire mesh.
[0023]
[Example 2]
By the above method, a PTFE resin green tape having a thickness of 0.2 μm was prepared, and three pieces of PTFE resin were respectively provided above and below the wire mesh (wire diameter: 0.1 mmφ, 100 mesh) as shown in FIG. The green tape was bonded and passed through a calender roll, and pressed under the conditions of a linear pressure of 140 kg / cm, a roll gap of 400 μm, and a temperature of 30 ° C. Subsequently, it was baked at 380 ° C. for 10 minutes to obtain a PTFE resin laminated sheet of the present invention having a thickness of 500 μm embedded with a wire mesh.
[0024]
【The invention's effect】
As described above, according to the method for producing a PTFE resin laminated sheet of the present invention, a desired thickness can be obtained by pressing and baking once without repeating the step of impregnating the core material with the PTFE resin emulsion and the baking step. In addition, a PTFE resin laminated sheet having good physical properties as a structural member such as bending resistance and tear resistance can be produced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a raw material bar extruder for PTFE resin green tape according to the present invention.
FIG. 2 is a perspective view showing an apparatus for producing a PTFE resin green tape according to the present invention.
FIG. 3 is a perspective view showing an apparatus for producing a PTFE resin laminated sheet according to the present invention.
FIG. 4 is a perspective view showing an apparatus for producing a PTFE resin laminated sheet according to the present invention.
FIG. 5 is a perspective view showing an apparatus for producing a PTFE resin laminated sheet of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 PTFE resin raw material paste 11 Hydraulic apparatus 12 Extrusion port 13 Heater 14 PTFE resin raw material bar 15 Raw material bar winder 21 Hot water tank 22 Guide 23 Calendar roll 24 Guide roller 25 Extraction tank 26 Dryer 27 Winder 28 Slitter 29 PTFE resin Unbaked tape 30 Wire mesh 31 Calendar roll 32 Baking machine 33 PTFE resin laminated sheet

Claims (4)

Paste-shaped tetrafluoroethylene resin fine particles are extruded, pressed to form a tetrafluoroethylene resin green tape, this tetrafluoroethylene resin green tape and a metal mesh are bonded, then pressed. A method for producing a tetrafluoroethylene resin laminated sheet, characterized by being fired.   The method for producing a tetrafluoroethylene resin laminated sheet according to claim 1, wherein the tetrafluoroethylene resin non-fired tape is bonded to both sides of the wire mesh, pressed, and subsequently fired.   3. The method for producing a tetrafluoroethylene resin laminated sheet according to claim 1, wherein a plurality of sheets of tetrafluoroethylene resin green tape are bonded to the wire mesh.   The method for producing a tetrafluoroethylene resin laminated sheet according to any one of claims 1 to 3, wherein the tetrafluoroethylene resin fine particles are produced by an emulsion polymerization method.

Images