JP2019163434A - Solid molding of fluorine resin and metal oxide, and method for producing the solid - Google Patents

Abstract

To provide various round-bar solid moldings, such as films or rods, formed by mixing fluororesin fine particles with metal oxide fine particles, and a method for producing the solid.SOLUTION: The present invention provides a fluorine resin-metal oxide solid mixture in which fluorine resin fine particles with a particle size of 100-500 nm and fine particles of one or more metal oxides with a particle size of 5-200 nm are uniformly dispersed mixedly.SELECTED DRAWING: Figure 1

Description

  The present invention relates to various round bar molded body solids such as films and rods composed of a mixture of fluororesin fine particles and metal oxide fine particles, the solids, and a method for producing the same.

Fluorine resin is superior to ordinary plastics such as polyethylene and polypropylene and organic polymers, and has excellent heat resistance and cold resistance, and has high resistance to various chemicals including acids and alkalis, that is, high chemical resistance and corrosion resistance. .
In addition, fluororesin is nonflammable, has high electrical insulation and low dielectric loss, is non-adhesive and non-wetting, repels water and oil, and has low friction and moderate elasticity.
For this reason, fluororesins are actively used for various materials such as molds, containers, electric wires, thermometers, various sensors, gaskets, packings, and frying pans, and product surface coatings.
The coating of fluororesin is usually performed by lining a fluororesin film, coating or impregnating a dispersion of fluororesin fine particles (for example, see Patent Document 1).

As described above, the fluororesin is nonflammable and excellent in heat resistance compared to other organic polymers.
However, the thermal expansion coefficient of fluororesin is approximately an order of magnitude larger than that of other organic polymer resins.
In addition, the fluororesin is softer than other organic polymers.
For example, the thermal expansion coefficient at room temperature (x10 ⁻⁶ / ° C.) is acrylonitrile butadiene styrene (ABS) resin, polyamide (PA), polyimide (PI), polycarbonate (PC), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and epoxy resin (EP) are 74, 80, 54, 70, 60, 70 and 62, respectively, while the fluororesin is 200-790.
For this reason, the dimensions of the fluororesin are not stable, and it is difficult to perform surface treatments such as coating and modification that are beneficial for multi-functionality and high functionality.

Fluororesin is also an extremely excellent insulating material and is very easily charged.
In fact, it is positioned as a substance that is most likely to be negatively charged in the charge train.
Since electrification can cause flammable explosions of flammable gases and solvents and dielectric breakdown of fluororesin products themselves, antistatic and antistatic measures for fluororesins were extremely important.

The charging is usually removed by attaching a ground to the fluororesin or its product, or mixing a conductive material with the fluororesin, but such a method is often difficult.
For example, surface coating and modification are operations / processes that are frequently or indispensably performed to achieve multiple functions and high performance. However, in the case of a fluororesin that is extremely easily and strongly charged, the coating liquid is repelled due to the charging, and coating is often impossible.
At this time, when grounding is used, workability is deteriorated.
In addition, when the current conductive material, that is, carbon black (CB), carbon fiber (CF), carbon nanotube (CNT), or metal fine powder is mixed with fluororesin, the coating formed on the surface resulting from the mixing or subsequent coating It may not fit the modification.

  Furthermore, although the non-wetting property and non-adhesiveness of the fluororesin have a great advantage that they are difficult to get dirty, the coating solution is difficult to be applied to surface coating and modification, which is a major obstacle.

In the fluororesin, an inorganic filler is added to the fluororesin in order to improve / improve wear resistance, compression resistance, cold flow resistance, sliding characteristics, conductivity, and the like.
As the inorganic filler, glass fiber, carbon fiber, graphite, carbon, CNT, molybdenum disulfide, silica, or the like is used.
However, these inorganic fillers are not intended to modify the surface properties for multifunctional / high functionality of the fluororesin, such as adjustment and improvement of wettability, adhesiveness, and chargeability.
For this reason, it has been difficult to say that the addition of the inorganic filler (additive) matches the modification of the surface characteristics.

Conventional inorganic filler-containing fluororesin solids are usually evaporated to dryness of an aqueous dispersion of fluororesin fine particles to which filler components have been added and mixed in advance, or kneading of fluororesin powder and filler powder. And after that, it is obtained by subjecting it to a molding treatment if necessary.
In general, it is expected that the degree of mixing, that is, the mixing and dispersibility of each particle, is higher when the mixed dispersion is evaporated to dryness than when the powders are kneaded.
In order to actually obtain a high degree of mixing, it is essential that the fluororesin fine particles and the filler component are uniformly dispersed and mixed in the mixed solution.
However, there are very few types of fillers that become a homogeneous mixed dispersion by adding and mixing the filler to the fluororesin fine particle aqueous dispersion.

In Patent Documents 2 to 4, colloidal sol solution of inorganic fine particles, specifically silica, titanium oxide, zeolite, aluminum oxide (alumina), zinc oxide, antimony pentoxide, as a filler that is uniformly dispersed by mixing with a fluororesin emulsion. Silicon carbide, silicon nitride, aluminum nitride, lead oxide, tin oxide, magnesium oxide, etc. are described, and many types of fillers are said to be suitable for the preparation of a homogeneous mixed dispersion with a fluororesin emulsion.
However, in the examples in Patent Documents 2 to 4, the preparation of the uniform mixed dispersion is all limited to silica, and no examples are described for colloidal solutions of inorganic fine particles other than silica.

Moreover, most of the fillers that are uniformly dispersed by mixing with the fluororesin emulsion are silica sols and organosilicate solutions that are excellent in viscosity stability, and alumina sols are known to some extent (Patent Documents 1 to 6).
In addition, these additions are aimed at improving the mechanical strength, heat resistance, dimensional stability, compression creep properties and melt moldability of the fluororesin solids finally obtained. Not intended.

In addition, a fluororesin-metal oxide mixed solution in which a fluororesin emulsion and a metal oxide are mixed may be liquid-liquid separation or solid-liquid if the metal oxide is evenly dispersed immediately after mixing but left for a while. There was a disadvantage of causing separation.
Therefore, it is difficult to obtain mixed dispersions as well as solid materials such as filler-containing fluororesin powders and films intended to modify and adjust the surface properties of the fluororesin.

JP 2006-117900 A JP 2007-119769 A JP 2008-115335 A JP 2008-115336 A JP-A-8-258228 JP 2012-219126 A

  The present invention has been made to solve the above problems, and provides a solid material in which fluororesin fine particles and a metal oxide are uniformly dispersed, and a method for producing the same.

In order to solve the above-mentioned problems, the present inventors have extensively searched for a combination of a fluororesin fine particle aqueous dispersion or emulsion and a metal oxide colloidal sol, and repeated trial and error for their blending / preparation method, Researched earnestly.
The inventors of the present invention uniformly mixed a fluororesin fine particle having a particle size of 100 to 500 nm and one or more metal oxide fine particles having a particle size of 5 to 200 nm by quickly drying the liquid that has been mixed and stirred to a uniform state. The present inventors have discovered a fluororesin-metal oxide mixed solid that has been dispersed and whose wettability, adhesion, and chargeability on the surface of a solid such as a film, coating film, and bulk are adjusted and improved, and a method for producing the same.

  The invention according to claim 1 relates to a fluororesin-metal oxide mixed solid in which fluororesin fine particles having a particle size of 100 to 500 nm and one or more metal oxide fine particles having a particle size of 5 to 200 nm are uniformly mixed and dispersed. .

The invention according to claim 2 is a polymer or copolymer of monomers in which the fluororesin fine particles are selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride and vinyl fluoride. 2. The fluororesin-metal oxide mixed solid according to claim 1, which is a resin fine particle composed of a coalescence and has a molecular weight of 1 × 10 ⁴ to 1 × 10 ⁷ .

  The invention according to claim 3 is characterized in that the metal oxide is one or more metal oxides selected from alumina, titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, iron oxide, tin oxide and niobium oxide. The fluororesin-metal oxide mixed solid according to claim 1 or 2, which is a product.

  In the invention according to claim 4, the fluororesin content in the fluororesin-metal oxide mixed solid is 3 to 100 times the metal oxide content in weight ratio. The fluororesin-metal oxide mixed solid described in the item.

According to a fifth aspect of the invention, an aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol are fluorine at a weight ratio with respect to the content of metal oxide fine particles in the liquid at a temperature of 5 to 300 ° C. under normal pressure. A step of obtaining a uniform mixed dispersion by mixing resin fine particles 3 to 100 times and water 10 to 120 times and further adding a surfactant or without adding a surfactant;
A step of producing a uniform mixed powder by spray-drying the uniform mixed dispersion liquid, wherein the fluororesin-metal oxide mixed solid according to any one of claims 1 to 4 is used. It relates to a manufacturing method.

  In the invention according to claim 6, the method for producing the fluororesin-metal oxide mixed solid from the homogeneously mixed powder includes a doctor blade method, pressurization, pressurization / heating, melting, and an extrusion or stretching operation thereof. The process for manufacturing a fluororesin-metal oxide mixed solid according to claim 5, comprising a treatment step selected from the group consisting of:

In the fluororesin-metal oxide mixed solid of the present invention, fluororesin and metal oxide fine particles are uniformly mixed and dispersed with each other.
In other words, the original size and the size close to the original size, in other words, the nanoparticles are uniformly dispersed and mixed at the size level.
Therefore, it can be easily formed into a film or a bulk body of a desired shape by heat and / or pressure.
Further, the method for producing a mixed solid of the present invention is based on the content of the metal oxide fine particles in the liquid at a temperature of 5 to 300 ° C. under normal pressure with an aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol. Because it is manufactured by mixing fluororesin fine particles 3 to 100 times and water 10 to 120 times by weight ratio and spray drying, it is simple, energy-saving, extremely safe and extremely economical. .
In addition, the fluororesin-metal oxide mixed solid of the present invention has a low coefficient of thermal expansion and excellent dimensional stability as compared with a solid made of fluororesin.

It is a SEM photograph in one embodiment of the fluororesin-metal oxide mixed solid of the present invention. It is a SEM photograph in other embodiments of the fluororesin-metal oxide mixed solid of the present invention.

<Configuration of fluororesin-metal oxide mixed solid>
The fluororesin-metal oxide mixed solid of the present invention is basically obtained by mixing a fluororesin fine particle dispersion (emulsion) and a metal oxide fine particle dispersion (sol) and spray drying. Thus, the fluororesin fine particles and the metal oxide fine particles are uniformly dispersed and mixed at the particle size level.
In addition, the fluororesin-metal oxide mixed solid of the present invention includes fluororesin fine particles (powder) and metal oxide fine particles (powder), fluororesin fine particles (powder) and metal oxide fine particle dispersion (sol). Alternatively, a fluororesin fine particle dispersion (emulsion) and metal oxide fine particles (powder) may be mixed to produce.

  The fluororesin fine particle in the present invention is a resin composed of a polymer or copolymer of a monomer selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride and vinyl fluoride. Fine particles which are dispersed in water are used for preparing the fluororesin-metal oxide mixed solid of the present invention.

  The metal oxide fine particles in the present invention are titanium oxide (titania), zirconium oxide (zirconia), lanthanum oxide (lanthana), neodymium oxide, cerium oxide (ceria), yttrium oxide (yttria), tin oxide, iron oxide, niobium oxide. , And aluminum oxide (alumina), and an aqueous colloidal sol or powder of these fine particles is used to obtain the fluororesin-metal oxide mixed solid of the present invention.

In order to increase the degree of mixing of the fluororesin and the metal oxide, it is preferable that the fluororesin fine particles and the metal oxide fine particles have a small molecular weight and a small size. More specifically, the fluororesin fine particles preferably have a molecular weight of 1 × 10 ⁴ to 1 × 10 ⁷ and a particle size in the range of 100 to 500 nm, and the metal oxide fine particles have a size of 2 to 150 nm. Is preferably in the range of 2 to 50 nm.
The molecular weight of the fluororesin fine particles is preferably 1 × 10 ⁴ to 1 × 10 ^7, more preferably 2 × 10 ⁴ to 1 × 10 ⁷ .
When the particle size is smaller than the above range, the coating film tends to be brittle, and when the particle size is larger than the above range, the melt viscosity is too high and the particles of the fluororesin fine particles tend to be difficult to fuse. .

The fluororesin content in the fluororesin-metal oxide mixed solid is appropriately determined according to the use of the mixed powder, but if the fluororesin content is too low, flexibility and flexibility are lost. On the other hand, when the amount is too large, wettability and adhesiveness are not exhibited on the surface, and the surface is easily charged and the amount thereof is increased.
Therefore, the content of the fluororesin in the fluororesin-metal oxide mixed solid is preferably 1 to 500 times, more preferably 3 to 100 times the content of the metal oxide by weight ratio. preferable.
At this time, the type of metal oxide to be mixed may be one type or two or more types, and can be appropriately selected according to the purpose.

<Method for producing fluororesin-metal oxide mixed solid>
The fluororesin-metal oxide mixed solid of the present invention is produced by mixing an aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol, and spraying and drying, or simply drying.
The composition of the mixture of the aqueous dispersion of fluororesin fine particles and the metal oxide fine particle sol is 1 to 500 times, preferably 3 to 100 times, preferably 3 to 100 times greater than the content of metal fine particles. It is desirable to be in the range of 5 to 200 times, preferably 10 to 120 times.
The aqueous dispersion of fluororesin fine particles may be obtained by dissolving fluororesin powder in water, or a commercially available aqueous dispersion.

The mixing method of the aqueous dispersion of fluororesin fine particles and the metal oxide fine particle sol is a mixed liquid in which the mixed liquid of the aqueous dispersion of fluororesin fine particles and the metal oxide fine particle sol is uniformly mixed and dispersed even for a moment. As long as it becomes, it is not specified.
Therefore, normally, a mixed powder in which the fluororesin fine particles and the metal oxide fine particles are uniformly mixed and dispersed can be obtained simply by spraying and drying a mixed solution in which the viscosity is uniformly mixed and dispersed at room temperature under normal pressure.
Of course, if the viscosity of the liquid mixture is too high, the spraying / drying process will not proceed smoothly. For this reason, to achieve an appropriate viscosity, dilution, temperature and pressure should be made higher or lower than room temperature and normal pressure, respectively. May be adjusted.

When a mixture of an aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol easily forms a mixed solution that is uniformly mixed and dispersed, or when liquid-liquid separation occurs without sufficient mixing Similarly, a mixed powder in which fluororesin fine particles and metal oxide fine particles are uniformly mixed and dispersed can be easily obtained.
It is easy to obtain a mixed solution in which liquid-liquid separated liquid mixture is uniformly mixed and dispersed by stirring, especially high-speed stirring, or by jet-jet mixing of liquid-liquid-separated solutions. To obtain a uniformly mixed and dispersed powder.
Moreover, even for a mixed liquid that is liquid-liquid separated if no surfactant is added, it is possible to obtain a mixed liquid that is uniformly mixed and dispersed by stirring, particularly high-speed stirring, or by jet-jet mixing of liquid-liquid separating solutions. Since it is easy to obtain a uniformly mixed and dispersed powder by performing spraying and drying operations in this state, it is possible to produce a uniformly mixed and dispersed powder without adding a surfactant.
In the present invention, a surfactant may or may not be added to the aqueous dispersion of fluororesin fine particles and the metal oxide fine particle sol.
Surfactants are blended to increase intermolecular force, but because of the effect, there was a tendency for powders to become agglomerated, so we added 1% to 10% alumina sol to the Teflon dispersion, When necessary, clay was added, mixed without a surfactant, and sprayed / dried. As a result, a good powder was obtained.
This homogeneous mixed powder is a fluororesin-metal oxide mixed solid by a treatment process selected from the group consisting of a doctor blade method, pressurization, pressurization / heating, melting, and a combination thereof with an extrusion or stretching operation. Manufacturing.

Precipitation and gelation are caused by aggregation / aggregation of particles and huge cross-linking between particles with a solvent or the like interposed between the particles.
Therefore, in order to prevent precipitation and gelation, it is necessary to first prevent aggregation / aggregation and cross-linking of particles. As a measure for this, it is usually to repel particles or increase the distance between particles. Done. Specifically, the particles are given the same charge (charged) to repel each other, the particles are surrounded by a surfactant to form a composite micelle, or more simply diluted with a solvent.
In the case of a metal oxide colloid, even when a composite micelle is formed, the particles are repelled and dispersed by charging.

In general, the charge amount of the particles is closely related to the pH of the solution. In other words, it is extremely sensitive to pH.
Therefore, the pH of the metal oxide sol used for the preparation of the fluororesin-metal oxide mixed dispersion also has an appropriate range for preventing the aggregation, and this varies depending on the metal species.
Thus, the pH of the metal oxide sol used in the present invention is 2.5 to 13.5 for titania, more preferably 3 to 13, and 6.5 to 9 for zirconia, more preferably 7 to 8.5, 7-10 for Lantana, more preferably 7.5-9.5, 7 or more for neodymium oxide, more preferably 7-10, 6-10 for ceria. Yes, more preferably 7-9, tin oxide 2-12, more preferably 2-11, iron oxide 5.5-8.5, more preferably 6-8 In the case of alumina, it is 3.4 to 9.5, more preferably 4.7 to 8.5.
If the pH of each metal oxide sol is out of the above range, gelation and precipitation are likely to occur in mixing with the fluororesin fine particle aqueous dispersion, depending on the type of fluororesin fine particle aqueous dispersion used. It becomes difficult to spray from the nozzle.

The preparation of the fluororesin-metal oxide mixed dispersion used in the spraying / drying step is greatly influenced not only by the pH of the metal oxide sol used but also by the pH of the fluororesin fine particle aqueous dispersion.
This is because the pH of the mixture produced by mixing the metal oxide sol and the fluororesin fine particle aqueous dispersion changes, and at the same time, depending on the metal oxide sol used, precipitation occurs or gelation occurs due to the change in pH.
Accordingly, the pH of the fluororesin fine particle aqueous dispersion used for preparing the fluororesin-metal oxide mixed dispersion is generally preferably 10 or more, although it depends on the metal oxide sol used.

The aggregation / aggregation of fine particles is closely related to the concentration. When the concentration is high, not only thickening and coagulation / gelation are likely to occur, but also aggregation and precipitation are likely to occur.
Therefore, solvent dilution that is usually performed is also effective.
However, too much dilution, that is, too low a particle concentration, is uneconomical because it consumes a great deal of energy for the evaporation and scattering of the solvent in the spraying and drying process. From this point of view, a higher particle concentration is preferable. .
From this viewpoint, as described above, the fluororesin fine particles are 1 to 500 times, more preferably 3 to 100 times, and water is 5 times by weight with respect to the content of the metal oxide fine particles in the entire liquid. It is desired to be in the range of ˜200 times, more preferably in the range of 10 to 120 times.

<About raw materials>
The fluororesin fine particle aqueous dispersion used in the present invention may be commercially available, for example, 31-JR (PTFE solid content: 60% by weight, average molecular weight: 2 × 10 ⁴ to 1 × 10 ⁷ , PTFE primary particles manufactured by Mitsui Fluoro. Average particle diameter: 0.25 μm, pH: 10.5), Daikin polyflon D-111 (PTFE solid content: 60% by weight, average molecular weight: 2 × 10 ⁴ to 1 × 10 ⁷ , average of PTFE primary particles Particle size: 0.25 μm, pH: 9.7), AD911E manufactured by Asahi Glass (PTFE solid content: 60% by weight, average molecular weight: 2 × 10 ⁴ to 1 × 10 ⁷⁾ , average particle size of PTFE primary particles: 0.00. 25 μm, pH: 10) and the like may be used, but are not limited thereto.
Further, as the fluororesin fine particles (powder), PTFE molding powder “M81” (manufactured by Todake Co., Ltd.) or the like may be used, but is not limited thereto.

The metal oxide sol used in the present invention may be commercially available, for example, Tynoch A-6 (TiO ₂ wt%: 6, average particle size nm: 10-20, pH: 11-13) manufactured by Taki Chemical, viral Zr—C20 (ZrO ₂ wt%: 20, average particle diameter nm: 20, pH: 7), viral Nb-G6000 (Nb ₂ O ₃ wt%: 6, average particle diameter nm: 15, pH: 8), viral Al-L7 (Al2O3 wt%: 7, average particle diameter nm: 5-10, pH: 8) may be used, but is not limited thereto.
As the alumina sol, for example, alumina sol-10A (Al ₂ O ₃ equivalent weight%: 9.8 to 10.2, average particle diameter nm: 5-15, viscosity 25 ° C., mPa / s: <50, pH: 3.4-4.2, manufactured by Kawaken Fine Chemical Co., Ltd.), Alumina Sol-A2 (Al ₂ O ₃ equivalent weight%: 9.8 to 10.2, Average particle diameter nm: 10-20, Viscosity 25 ° C., mPa / s : <200, pH: 3.4-4.2, manufactured by Kawaken Fine Chemical Co., Ltd., Alumina Sol-CSA-110AD (Al ₂ O ₃ equivalent weight%: 6.0-6.4, average particle diameter nm: 5-15 , Viscosity 25 ° C., mPa / s: <50, pH: 3.8-4.5, manufactured by Kawaken Fine Chemical), Alumina Sol-F1000 (Al ₂ O ₃ equivalent weight%: 4.8-5.2, average particle) Diameter nm: 1400, viscosity 25 ° C, mP /S:<1000,PH:2.9-3.3, manufactured by Kawaken Fine Chemicals), alumina sol -F3000 _(Al 2 _{O 3} in terms of weight%: 4.8-5.2, an average particle size nm: 2000-4500 Viscosity 25 ° C., mPa / s: <1000, pH: 2.7-3.3, manufactured by Kawaken Fine Chemical Co., Ltd.) and the like may be used, but are not limited thereto.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

[Example 1]
In Example 1, alumina resin sol (alumina sol “A2” (manufactured by Kawaken Fine Chemicals Co., Ltd.)) as a metal oxide was mixed with fluororesin fine particles (PTFE molding powder “M81” (manufactured by Todake Co., Ltd.)), spray-dried, and fluorine A resin-metal oxide mixed solid was produced.
The mass concentration and the number of atoms of the mixed solid are summarized in Table 1.

[Example 2]
Example 2 is made of fluororesin fine particles (PTFE molding powder “M81” (manufactured by Todake Co., Ltd.)), alumina sol (alumina sol “A2” (manufactured by Kawaken Fine Chemical Co., Ltd.)) as a metal oxide, and a metal that easily undergoes phase separation. Certain niobium (Bialal Nb-G6000 (Nb ₂ O ₃ wt%: 6, average particle size nm: 15, pH: 8)) was mixed and spray-dried to produce a fluororesin-metal oxide mixed solid.
Table 2 summarizes the mass concentration and the number of atoms of the mixed solid.

As shown in FIG. 1, it can be understood that the fluororesin fine particles and the metal oxide fine particles were uniformly mixed and dispersed by using the method of the present invention.
Further, as shown in FIG. 2, in the case of mixing the fluororesin fine particles and the metal oxide sol, even if phase separation occurs, the metal oxide fine particles and the fluororesin fine particles are uniform if spray drying is performed immediately after stirring at high speed. It can be seen that they are mixed and dispersed. Therefore, it turns out that spray drying is a very important operation.

  By virtue of the present invention, it is easy to cause separation by mixing with fluororesin fine particles. On the contrary, even if a metal oxide sol that would be separated immediately when stirring is stopped, by vigorously stirring and immediately spray drying, fluororesin fine particles And a powder in which metal oxide fine particles are uniformly mixed and dispersed can be obtained.

[Example 3]
In Example 3, the thermal expansion coefficient of the fluororesin-metal oxide mixed solid according to the present invention was measured. The thermal expansion coefficients of the following Examples 3-1 to 3-3 and Comparative Examples 1-2 were measured.

<Example 3-1>
Example 3-1 was prepared by mixing the following fluororesin (powder) and alumina sol (liquid).
Fluorine resin: PTFE molding powder “M81” (manufactured by Tougaku)
Alumina sol: Alumina sol "A2" (manufactured by Kawaken Fine Chemical Co., Ltd.)
Example 3-1 was produced by the following procedure using the fluororesin and alumina sol.
-35.59 g of fluororesin (powder) and 3.6 g of alumina sol (liquid) were placed in a plastic bottle and stirred.
-A mixed liquid of fluororesin (powder) and alumina sol (liquid) was put in a PFA tray and dried at 120 ° C for 2 hours in a drying furnace.
A mold for molding was filled with a mixture of dried fluororesin (powder) and alumina sol (powder).
-Pressurized with a surface pressure of 40 MPa using an Amsler tester.
-After slow pressure, the molded body was removed from the mold.
-The molded object was baked at 380 degreeC for 3 hours using the electric furnace.

<Example 3-2>
Example 3-2 was prepared by mixing the following fluororesin (powder) and alumina sol (powder).
Fluorine resin: PTFE molding powder “M81” (manufactured by Tougaku)
Alumina sol: Alumina sol "A2" (manufactured by Kawaken Fine Chemical Co., Ltd.)
Example 3-2 was produced by the following procedure using the fluororesin and alumina sol.
Alumina sol (liquid) was put in an aluminum cup and dried at 120 ° C. for 2 hours in a drying furnace.
-The dried alumina sol (powder) was pulverized into powder in a mortar.
-35.59 g of fluororesin (powder) and 3.6 g of pulverized alumina sol (powder) were placed in a plastic bottle and stirred.
A mixture of fluororesin (powder) and alumina sol (powder) was filled into a molding die.
-Pressurized with a surface pressure of 40 MPa using an Amsler tester.
-After slow pressure, the molded body was removed from the mold.
-The molded object was baked at 380 degreeC for 3 hours using the electric furnace.

<Example 3-3>
Example 3-3 was prepared by mixing the following fluororesin (liquid) and alumina sol (liquid).
Fluororesin: PTFE dispersion "D-111" (Daikin)
Alumina sol: Alumina sol "A2" (manufactured by Kawaken Fine Chemical Co., Ltd.)
Example 3-3 was produced by the following procedure using the fluororesin and alumina sol.
-58.8 g of fluororesin (liquid) and 18.5 g of alumina sol (liquid) were put in a plastic bottle and stirred.
-A mixed liquid of fluororesin (liquid) and alumina sol (liquid) was put in an aluminum dish and dried in an electric furnace at 300 ° C for 48 hours.
A mold for molding was filled with a mixture of dried fluororesin (powder) and alumina sol (powder).
-Pressurized with a surface pressure of 40 MPa using an Amsler tester.
-After slow pressure, the molded body was removed from the mold.
-The molded object was baked at 380 degreeC for 3 hours using the electric furnace.

<Comparative Example 1>
The comparative example 1 was produced using the following fluororesins (powder).
Fluorine resin: PTFE molding powder “M81” (manufactured by Tougaku)
Using the fluororesin, Comparative Example 1 was produced according to the following procedure.
-35.66 g of fluororesin (powder) was filled in a molding die.
-Pressurized with a surface pressure of 40 MPa using an Amsler tester.
-After slow pressure, the molded body was removed from the mold.
-The molded object was baked at 380 degreeC for 3 hours using the electric furnace.

<Comparative example 2>
Comparative Example 2 was prepared using the following fluororesin (liquid).
Fluororesin: PTFE dispersion "D-111" (Daikin)
Using the fluororesin, Comparative Example 2 was produced according to the following procedure.
-59.7 g of fluororesin (liquid) was put in an aluminum dish and dried at 300 ° C. for 48 hours in an electric furnace.
-The mold for molding was filled with the dried fluororesin (powder).
-Pressurized with a surface pressure of 40 MPa using an Amsler tester.
-After slow pressure, the molded body was removed from the mold.
-The molded object was baked at 380 degreeC for 3 hours using the electric furnace.

Using the produced Examples 3-1 to 3-3 and Comparative Examples 1 and 2, the linear expansion coefficient was measured under the following conditions.
Measuring method: TMA (Thermo-mechanical analysis)
Measuring instrument: TMA / SS7100 (manufactured by SII Nanotechnology)
Measurement temperature range: 30 ° C to 300 ° C
The results of linear expansion coefficient measured under the above conditions are shown in Table 3 below.

From the measurement results of the linear expansion coefficient shown in Table 3, it can be seen that Example 3-1 and Example 3-2 have a smaller linear expansion coefficient than Comparative Example 1 using the same fluororesin. It was.
Moreover, in Example 3-3, it was found that the linear expansion coefficient was greatly reduced as compared with Comparative Example 2 using the same fluororesin.
From these results, it was found that the fluororesin-metal oxide mixed solid according to the present invention has a lower coefficient of thermal expansion than the fluororesin solid and can suppress thermal expansion.

According to the present invention, the thermal expansion and charging of the fluororesin are suppressed, and since the water contact angle is small, the hydrophobicity is weakened and the wettability and adhesiveness are improved. It has become possible to increase the functionality and functionality of the resin surface.
In addition, the incorporation of the metal oxide according to the present invention hardens the fluororesin and increases the heat resistance, and at the same time has the effect of becoming a scratch-resistant surface.

A powder in which each of titania, zirconia, lantana, ceria, tin oxide and alumina is uniformly mixed and dispersed in fluororesin fine particles by the method of the present invention is manufactured, and these films are pressure-bonded to a SUS film to form a coating film. It was confirmed that various liquids and sols were uniformly wetted and a good coating film was formed.
On the other hand, in the conventional fluororesin film containing no metal oxide, all the sols tried were repelled. Since the surface of the conventional fluororesin alone is soft, it is easily scratched when it comes into contact with a hard material. However, in the fluororesin of the present invention, for example, zirconia sol (organic polymer When a paint was applied and dried, a very hard coating film was formed on the film surface, and the surface became very difficult to be damaged.

The fluororesin-metal oxide mixed solid of the present invention is a fluororesin film, mold material, bulk fluororesin molded body such as a fluororesin film having improved / adjusted properties of the fluororesin, specifically wettability, adhesiveness, heat resistance and Since it has improved hardness and is less likely to be charged, it is suitable for the production of fluororesins that require these characteristics and molded articles thereof.
Further, since the powder and film according to the present invention have the above-mentioned characteristics, specifically, as a surface coating material or lining having good adhesion and high heat resistance and high degree, specifically, an electric wire, a thermometer, various sensors, and a gasket. In addition to being used as a coating film and lining for various materials and product surfaces such as packing and packing, it exhibits extremely excellent performance as an undercoating material in multi-layer and multi-stage coating for multi-function and high-function.

Claims (6)

  A fluororesin-metal oxide mixed solid in which fluororesin fine particles having a particle size of 100 to 500 nm and one or more metal oxide fine particles having a particle size of 5 to 200 nm are uniformly mixed and dispersed. The fluororesin fine particles are resin fine particles comprising a polymer or copolymer of a monomer selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride and vinyl fluoride, and 2. The fluororesin-metal oxide mixed solid according to claim 1, which has a molecular weight of 1 × 10 ⁴ to 1 × 10 ⁷ .   The metal oxide is one or more metal oxides selected from alumina, titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, iron oxide, tin oxide, and niobium oxide. The fluororesin-metal oxide mixed solid described in 1.   The fluororesin-metal according to any one of claims 1 to 3, wherein a fluororesin content in the fluororesin-metal oxide mixed solid is 3 to 100 times the metal oxide content by weight. Oxide mixed solid. The aqueous dispersion of fluororesin fine particles and the metal oxide fine particle sol are used at a temperature of 5 to 300 ° C. under normal pressure, and the fluororesin fine particles are added 3 to 100 times in weight ratio to the content of the metal oxide fine particles in the liquid. A step of obtaining a homogeneous mixed dispersion by mixing water at 10 to 120 times, further adding a surfactant or without adding a surfactant,
A step of producing a uniform mixed powder by spray-drying the uniform mixed dispersion liquid, wherein the fluororesin-metal oxide mixed solid according to any one of claims 1 to 4 is used. Production method.   The method for producing the fluororesin-metal oxide mixed solid from the uniformly mixed powder is selected from the group consisting of a doctor blade method, pressurization, pressurization / heating, melting, and a combination of these and extrusion or stretching operations. The manufacturing method of the fluororesin-metal oxide mixed solid of Claim 5 characterized by including the processing process which comprises.