JP2017203152A - Fluorine resin-metal oxide mixed dispersion and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixed dispersion (sol) liquid of fluorine resin fine particles and metal oxide fine particles excellent in operativity and workability in a coating step.SOLUTION: An aqueous fluorine resin-metal oxide mixed dispersion is obtained by mixing an aqueous dispersion of fluorine resin fine particles and any one metal oxide fine particle sol out of titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide and tin oxide with a proper pH value, where the fluorine resin fine particles and the metal oxide fine particles float and are dispersed without causing coagulation settling, gelation/solidification and/or phase separation, and stably keeps a floating and dispersed state for 3 or more days when stored at room temperature, and a solid matter obtained by evaporation and scattering of a solvent from the fluorine resin-metal oxide mixed dispersion has a water contact angle of 130° or lower and surface resistivity of 2.0×10Ω/square or less.SELECTED DRAWING: None

Description

  The present invention relates to the surface of various materials such as metals, carbon, plastics, glass, ceramics, and wood, and the coating liquid for coating the surface of products made of these materials, the impregnating liquid for fibers and powders of the materials, and the production method thereof .

Fluorine resin is superior in heat resistance and cold resistance compared to ordinary plastics such as polyethylene and polypropylene, and organic polymers, and has high resistance to various chemicals including acid and alkali, that is, chemical resistance and corrosion resistance. Insulation and low dielectric loss, non-adhesive and non-wetting, water and oil repelling, low friction and moderate elasticity, mold material, container, electric wire, thermometer, various sensors It is used to coat various materials and product surfaces such as gaskets, packings and frying pans.
These coatings are usually performed by lining a fluororesin film, coating or impregnating a dispersion of fluororesin fine particles, and a wide variety of fluororesin films and dispersions are commercially available, and new products are being developed. (For example, Patent Document 1).

  However, fluoropolymers are nonflammable and have excellent heat resistance compared to other organic polymers, but because they are softer than other organic polymer resins, their dimensions during molding are difficult to stabilize, making them multifunctional and highly functional. It is difficult to perform surface treatment such as coating or modification that is beneficial to the environment.

  In addition, since the fluororesin is an extremely excellent insulating material, it is very easily charged, and is positioned as a substance that is most easily 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 are extremely important.

The removal of the charge is usually performed by attaching a ground to the fluororesin and its product or mixing a conductive material with the fluororesin, but such a method is often difficult.
For example, surface coating and modification are frequently performed operations / processes for multi-functionality and high performance, but fluororesin is very easily and strongly charged, so the coating solution is repelled and cannot be coated. There are many cases.
When the coating is not possible, workability is poor even if ground is used, and when carbon black (CB), carbon fiber (CF), carbon nanotube (CNT) or metal fine powders, which are current conductive materials, are mixed, The resulting surface may not be compatible with subsequent coatings or modifications.

  Furthermore, the non-wetting property and non-adhesiveness of the fluororesin have a great advantage that they are difficult to get dirty, but it is a major obstacle to surface coating and modification because the coating liquid is difficult to apply.

Usually, plastics made of organic polymers improve processability, weather resistance, durability, rigidity, impact resistance, slidability, wear resistance, flame resistance, heat resistance, sound insulation, gas shielding, etc. Therefore, an additive (filler) is mixed in order to improve surface characteristics such as antistatic or friction.
There are a wide variety of fillers, including metal oxides and metals, specifically talc, mica, silicon oxide (silica), titania, alumina, magnesia, graphite, molybdenum sulfide, calcium carbonate, iron powder, and other fine particles and fibers. These are selected and used according to the purpose and countermeasures (Non-Patent Documents 1-3).

  For example, talc, silica, calcium carbonate, alumina, montmorillonite, synthetic mica, etc. for mechanical and thermal reinforcement, CB, CNT, metal powder, etc. for electromagnetic and electrostatic countermeasures, silica, boron nitride, etc. for high frequency countermeasures, heat dissipation Aluminum nitride, boron nitride, alumina, etc., flame retardant aluminum hydroxide, magnesium hydroxide, antimony oxide, hydrotalcite, silica, etc., gas barrier measures, montmorillonite, synthetic mica, etc., anti-blocking measures Silver, zeolite, silver, silica, and the like are used as fillers for sterilization and antibacterial, such as silica, talc, and calcium carbonate (Non-patent Document 2).

In fluororesins, inorganic fillers are usually glass fibers, carbon fibers, graphite, carbon, CNT, molybdenum disulfide, silica, etc., which are mainly wear resistant, compression resistant, cold flow resistant, sliding properties. It is added to improve and improve conductivity.
These are not intended to modify the surface properties for multifunctional / high functionality of fluororesin, such as adjustment and improvement of wettability, adhesiveness, and chargeability, but match the modification of the surface properties. It's hard to say.

In general, solid molded articles such as fluororesin powders, films and coating films are obtained by evaporating moisture from the fine particle aqueous dispersion and drying. In such operations / processes, it is desirable that the filler component is added and mixed in advance to the fluororesin fine particle aqueous dispersion (emulsion) to form a homogeneous mixed dispersion of the fluororesin fine particles and the filler component (additive).
However, there are very few types of additives that can be added to and mixed with the fluororesin fine particle aqueous dispersion to form a uniform mixed dispersion.

Patent Documents 2-4 disclose colloidal sol solutions of inorganic fine particles as additives that are uniformly dispersed by mixing with a fluororesin emulsion. Specifically, silica, titanium oxide, zeolite, aluminum oxide (alumina), oxidation are disclosed. Zinc, antimony pentoxide, silicon carbide, silicon nitride, aluminum nitride, lead oxide, tin oxide, magnesium oxide, etc. are mentioned, and many kinds of additives are said to be suitable for preparing homogeneous mixed dispersion with fluororesin emulsion .
However, in the examples in the patent document, the preparation of the homogeneous mixed dispersion is limited to silica, and no examples are described for the colloidal solution of the inorganic fine particles other than silica. There is no description about the properties, composition, configuration, etc. of the fine particle sol, only the substance name of the inorganic fine particle sol is described.

Therefore, most of the additives that are uniformly dispersed by mixing with the fluororesin emulsion are silica sol and organosilicate solution with excellent viscosity stability, and only a part of alumina sol is known (Patent Documents 1-6).
These additions are aimed at improving the mechanical properties, heat resistance, dimensional stability, compression creep properties and melt moldability of the final fluoropolymer solids, and are intended to improve and adjust the surface properties. However, it is difficult to obtain a mixed dispersion that can be used to modify or adjust the surface properties of the fluororesin.

  For the reasons mentioned above, fillers (additives) intended to modify the surface properties for multifunctional and advanced functionality of fluororesins, specifically to adjust and improve wettability, adhesiveness, and chargeability This research and technical development are not yet developed for not only solids such as fluororesin powders, films and coating films, and molded articles thereof, but also aqueous dispersions of fluororesin fine particles, which are their origin.

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

Journal of the Japan Rubber Association, Vol. 75, No. 8, 330-332 (2002) Plastic Swage, April 2006, 72-80 Journal of Japan Rubber Association, Vol.82, No.2, 61-66 (2009)

  The present invention has been made to solve the above-mentioned problems of the prior art, and the inventors have extensively searched for a fine particle aqueous dispersion of fluororesin or a combination of an emulsion and a metal oxide colloidal sol. In addition to repeated trial and error with regard to their blending and preparation methods, and repeated earnest research, the final wettability, tackiness, and charging properties of solid surfaces such as fluororesin powders, films and coating films We have succeeded in developing a mixed dispersion (sol) in which fluororesin fine particles and metal oxide fine particles that can be adjusted and improved are suspended and dispersed uniformly in an aqueous solvent.

The invention according to claim 1 includes an aqueous dispersion of fluororesin fine particles, and metal oxide fine particle sol having an appropriate pH value of any one of titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, and tin oxide. An aqueous fluororesin-metal oxide mixed dispersion obtained by mixing the fluororesin fine particles and the metal oxide fine particles together without floating and dispersing without causing aggregation precipitation, gelation / coagulation and / or phase separation. The floating dispersion state is stably maintained for 3 days or more when stored at room temperature, and the water contact angle of the solid obtained by evaporating and scattering the solvent from the fluororesin-metal oxide mixed dispersion is The present invention relates to a fluororesin-metal oxide mixed dispersion characterized by being 130 ° or less and having a surface resistivity of 2.0 × 10 ¹² Ω / □ or less.

  In the invention according to claim 2, the appropriate pH value of the metal oxide fine particle sol is 2.5-13.5 for titanium oxide, 6.5-9 for zirconium oxide, 7-10 for lanthanum oxide, and neodymium oxide. 7. The fluororesin-metal oxide mixed dispersion according to claim 1, wherein 7-10, cerium oxide is 6.5-9.5, and tin oxide is 9-11.

  According to a third aspect of the present invention, the fluororesin-metal oxide mixed dispersion is in a weight ratio with respect to the content of the metal oxide fine particles in the dispersion, and the fluororesin fine particles are 3 to 100 times more water. It is comprised by 5-120 times, It is related with the fluororesin-metal oxide mixed dispersion of Claim 1 or 2.

  The invention according to claim 4 includes an aqueous dispersion of fluororesin fine particles, and metal oxide fine particle sol having an appropriate pH value of any one of titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, and tin oxide. At a temperature of 5 to 100 ° C. under normal pressure and mixed in a weight ratio with respect to the content of the metal oxide fine particles in the liquid, 3 to 100 times the fluororesin fine particles and 5 to 120 times the water. The method for producing a fluororesin-metal oxide mixed dispersion according to any one of claims 1 to 3.

  In the invention according to claim 5, the appropriate pH value of the metal oxide fine particle sol is 2.5-13.5 for titanium oxide, 6.5-9 for zirconium oxide, 7-10 for lanthanum oxide, and neodymium oxide. 7. The method for producing a fluororesin-metal oxide mixed dispersion according to claim 4, wherein 7-10, cerium oxide is 6.5-9.5, and tin oxide is 9-11.

The fluororesin-metal oxide mixed dispersion of the present invention has no aggregation or aggregation that causes precipitation of the fluororesin and metal oxide fine particles, and even when the original size or some aggregation occurs. The mixed dispersion of the present invention is applied to the object to be coated because it is uniformly mixed and dispersed in the water solvent in a size close to the size of the water, that is, in a size capable of floating and dispersing in the water solvent against gravity. The metal oxide-added fluororesin (Teflon (registered trademark)) layer can be coated at any thickness and with the fine accumulation of fine particles by a simple operation and work of impregnation or dipping (drying), drying and heat treatment. Since it starts, it can be applied without voids.
In addition, since the operation and work using the mixed dispersion of the present invention is simple, it is energy-saving and extremely safe, and is extremely excellent economically.

<Configuration of fluororesin-metal oxide mixed dispersion>
The fluororesin-metal oxide mixed dispersion of the present invention is basically an aqueous dispersion in which fluororesin fine particles and metal oxide fine particles composed of fluororesin fine particles, metal oxide fine particles and water are suspended and dispersed. In addition, the structure of a fluororesin-metal oxide mixed dispersion is not limited to these, The other structure may be contained.

In the present specification, the fluororesin fine particles are a polymer of monomers selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride, vinyl fluoride, and the like, or a copolymer thereof. It is preferable that it is the resin fine particle which consists of a polymer, and what disperse | distributes to water among these is used suitably for preparation of the fluororesin-metal oxide mixed dispersion liquid of this invention.
In addition, as long as it disperse | distributes to water, you may use monomers or copolymers other than the above-mentioned monomer.

  Further, the metal oxide fine particles in the present invention mean titanium oxide (titania), zirconium oxide (zirconia), lanthanum oxide (lanthanum), neodymium oxide, cerium oxide (ceria), tin oxide, and an aqueous colloidal sol of these fine particles. Is used to obtain the fluororesin-metal oxide mixed dispersion of the present invention.

In fluororesin fine particles and metal oxide fine particles, the particles tend to settle and precipitate as the size increases. Therefore, in order for the fluororesin and metal oxide fine particles to maintain a suspended dispersion state in an aqueous solvent for a long period of time, it is better that the size of the particles is small.
More specifically, the average particle diameter of primary particles is preferably in the range of 0.1 to 0.5 μm for fluororesin fine particles, and the average particle diameter for metal oxide fine particles is 2-150 nm, preferably 2- It is desirable to be in the range of 50 nm. However, the size of the fluororesin and metal oxide fine particles is not limited to the above as long as the suspended dispersion state can be maintained in an aqueous solvent for a long period of time. In addition, the average particle diameter of metal oxide microparticles | fine-particles is a median diameter at the time of measuring with "Dynamic light scattering type particle size distribution measuring device LB-500" by Horiba, Ltd.

In order to uniformly float and disperse particles in a solvent, not only the affinity with the solvent but also considerations and ideas for preventing the particles from aggregating are important. This is because the coagulation causes thickening and coagulation / gelation, resulting in precipitation. Therefore, it is necessary to prevent aggregation and aggregation of particles, and as a measure for this, the particles have the same charge (charge) and the particles are repelled, and the particles are surrounded by a surfactant and combined with the micelle. And so on.
In the case of a metal oxide colloid, even in the case of a composite micelle, many particles are repelled and dispersed by charging.

In general, the charge amount of the particles is closely related to the pH of the solution and is extremely sensitive to the pH. Therefore, the pH of the metal oxide sol used for the preparation of the fluororesin-metal oxide mixed dispersion of the present invention also has an appropriate range for preventing the aggregation, and this varies depending on the metal species.
The pH of the metal oxide sol used in the present invention is 2.5-13.5, preferably 3-13 for titania, 6.5-9, preferably 7-8.5 for zirconia, 7-10 for lantana, Preferably 7.5-9.5, neodymium oxide 7-10, preferably 7.5-9.5, ceria 6.5-9.5, preferably 7-9, and tin oxide 9-11 , Preferably 9.5 to 10.5.

  In general, the pH of the fluororesin fine particle aqueous dispersion used for the preparation of the fluororesin-metal oxide mixed dispersion is desirably 7-11.

  The pH range of the fluororesin-metal oxide mixed dispersion is preferably 1-13. The pH range is more preferably 3-12. The kind and amount of the fluororesin fine particle aqueous dispersion and the metal oxide sol are adjusted so that the pH range of the fluororesin-metal oxide mixed dispersion obtained by mixing both is within the above range, and a predetermined dispersion stability. It is desirable to set appropriately so that characteristics such as sex can be obtained. In addition, when the pH range of the obtained fluororesin-metal oxide mixed dispersion is out of 1-13, it is preferable to adjust the pH to be within the above pH range using an appropriate acid or alkali.

  In the present specification, the fact that the suspended dispersion state of the fluororesin-metal oxide mixed dispersion is stably maintained means that the fluororesin fine particles in the fluororesin-metal oxide mixed dispersion are kept at room temperature for at least 3 days. In addition, the state in which the metal oxide fine particles are both suspended and dispersed without causing aggregation, gelation / coagulation and / or phase separation is maintained.

The fluororesin-metal oxide mixed dispersion according to the present invention has a water contact angle of 130 ° or less and a surface resistivity of 2 when a solid is obtained by evaporating and scattering the solvent from the fluororesin-metal oxide mixed dispersion. 0.0 × 10 ¹² Ω / □ or less. A preferable range of the water contact angle is 120 ° or less.

Each value of the water contact angle and the surface resistivity in the present invention is obtained by the following measuring method.
The water contact angle is measured with an automatic contact angle meter by applying a fluororesin-metal oxide mixed dispersion on a glass substrate and drying it at 150 ° C./30 minutes.
The surface resistivity is obtained by applying a fluororesin-metal oxide mixed dispersion on a glass substrate with a spin coater (rotation speed: 16.67 s ⁻¹ / 10 seconds), and drying by ventilation at 150 ° C. for 30 minutes. The thin film is measured with a high resistivity meter.

As described above, the addition of a surfactant is often very effective in stabilizing the suspended and dispersed state of fine particles.
The surfactant to be added is selected in consideration of the affinity with the fine particles of metal oxide and fluororesin and the solvent, the electrostatic repulsion of the resulting composite micelles, etc., but the fluororesin fine particle aqueous dispersion and the metal oxide When a dispersion is obtained by simple mixing with a sol, the surfactant is not an essential component.
However, the addition of an appropriate amount of an appropriate surfactant may prolong the period for stably maintaining the dispersion state, and the present invention does not exclude the addition of a surfactant. Rather, a surfactant that is effective for extending the stability period, for example, a commonly used nonionic surfactant such as polyoxyalkylene alkyl ether or polyoxyalkylene alkylphenyl ether may be used.
When the pH range of the fluororesin-metal oxide mixed dispersion is deviated from 1-13 due to the addition of a surfactant, it is preferably adjusted to be within the above pH range using an appropriate acid or alkali. .

In the case where a surfactant is present in the fluororesin-metal oxide mixed dispersion, the surfactant may be subjected to certain kinds of metal oxide and / or fluororesin microparticles through van der Waals interaction or electrostatic interaction. By maintaining the intermolecular association, a uniformly dispersed state is maintained.
Instead of a surfactant, the surface of the metal oxide fine particles and / or fluororesin fine particles may be modified in advance with a substance that functions in a similar manner, or a modifier having such a role may be used as a metal oxide. It may be effective to add to the dispersion of each of the fine particles and / or fluororesin fine particles, and to maintain a uniform floating dispersion state of the fluororesin-metal oxide mixed dispersion for a long time. Processing may be performed.
Specifically, the above treatment can be exemplified by modifying the surface of the metal oxide fine particles with a silane coupling agent or the like, or adding a silane coupling agent or the like to the metal oxide fine particle sol. However, the modification method is not limited to these and may be a commonly used modification method.

Agglomeration of fine particles is closely related to its concentration.
When the concentration is high, the viscosity is increased and coagulation / gelation is likely to occur, and aggregation and precipitation are also likely to occur. Therefore, in order to achieve a uniform mixed dispersion state of the fluororesin fine particles and the metal oxide fine particles in the fluororesin-metal oxide mixed dispersion and to maintain it for a long period of time, it is necessary to lower the concentration of both fine particles in the liquid, that is, low The particle concentration is effective.
However, when the particle concentration is low, the film obtained by operations such as coating and impregnation is thin, and it is uneconomical because it consumes a great deal of energy for evaporation and evaporation of the solvent in heat treatment processes such as drying and baking. From this point of view, a higher particle concentration is preferable.
From this point of view, the fluororesin-metal oxide mixed dispersion is composed of the fluororesin fine particles 3-100 times and the water 5-120 times by weight with respect to the content of the metal oxide fine particles in the liquid. Desirably, but not limited thereto, any weight ratio may be selected to achieve the desired properties.

<Method for producing fluororesin-metal oxide mixed dispersion>
The fluororesin-metal oxide mixed dispersion according to the present invention is prepared by mixing an aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol with stirring.
The composition of the mixed solution is preferably prepared such that the fluororesin fine particles are 3 to 100 times and the water is 5 to 120 times by weight with respect to the content of the metal oxide fine particles.
There is no particular restriction on stirring during mixing, and optimum stirring conditions are appropriately selected in consideration of the particle concentration at the time of mixing, the viscosity of the liquid mixture, the liquid temperature, and the like.
The temperature at the time of stirring is usually room temperature, but it can be lowered or raised below room temperature in consideration of the viscosity of the mixed solution, and the stirring temperature is appropriately selected according to the situation.
There are no particular restrictions on the pressure during mixing and stirring, and the reaction is usually carried out under normal pressure. However, if pressurization or decompression is necessary from the viewpoint of viscosity or concentration of the solvent, the pressure can be appropriately selected according to the purpose.

<About raw materials>
In preparing the fluororesin-metal oxide mixed dispersion according to the present invention, the following aqueous dispersion and emulsion of fluorine fine particles and colloidal sol of metal oxide fine particles were used. In the present specification, symbols A-1 to A-3 and B-1 to B-7 are attached.

Fluorine resin fine particle aqueous dispersion A-1: PTFE 31-JR (PTFE solid content: 60% by weight, average molecular weight: 2 × 10 ⁴ −1 × 10 ⁷ , PTFE primary particles, manufactured by Mitsui DuPont Fluorochemical (Diameter: 0.1-0.5 μm, pH: 10.5)
A-2: manufactured by Daikin Industries, Polyflon (registered trademark) D-111 (PTFE solid content: 60% by weight, average molecular weight: 2 × 10 ⁴ −1 × 10 ⁷ , average particle size of PTFE primary particles: 0.1- 0.5 μm, pH: 9.7)
A-3: Asahi Glass, Fluon (registered trademark) PTFE dispersion AD911E (PTFE solid content: 60 wt%, average particle diameter of PTFE primary particles: 0.1-0.5 μm, average molecular weight: 2 × 10 ⁴ −1 × 10 ⁷ , pH: 10)

Metal oxide sol B-1: manufactured by Taki Chemical Co., Ltd., Tynock A-6 (TiO ₂ wt%: 6, average particle size: 20 nm, pH: 12)
B-2: manufactured by Taki Chemical Co., Ltd., Tynock AM-15 (TiO ₂ wt%: 15, average particle size: 20 nm, pH: 4)
B-3: manufactured by Taki Chemical Co., Ltd., Viral Zr-C20 (ZrO ₂ % by weight: 20, average particle size: 40 nm, pH: 8)
B-4: manufactured by Taki Chemical Co., Ltd., Viral La-C10 (La ₂ O ₃ wt%: 10, average particle size: 40 nm, pH: 8)
B-5: manufactured by Taki Chemical Co., Ltd., viral Nd-C10 (Nd ₂ O ₃ % by weight: 10, average particle size: 20 nm, pH: 9)
B-6: Nidral B-10 (manufactured by Taki Chemical Co., Ltd., CeO ₂ wt%: 10, average particle size: 20 nm, pH: 8)
B-7: manufactured by Taki Chemical, Cerames S-8 (SnO ₂ wt%: 8, average particle size: 8 nm, pH: 10)

<Uses of fluororesin-metal oxide mixed dispersion>
The fluororesin-metal oxide mixed dispersion of the present invention is a coating liquid for coating on the surfaces of various materials such as metals, carbon, plastics, glass, ceramics, and wood, and the surfaces of products made of these materials, and fibers and powders of the above materials. Suitable as a body impregnating solution, specifically, various materials such as electric wires, thermometers, various sensors, gaskets and packing, coating / coating materials for product surfaces, multi-layer / multi-stage for multi-function / high function Excellent performance as an undercoating material in coating.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example. In addition, the surface resistivity and water contact angle of the solid content obtained from the fluororesin-metal oxide mixed dispersion shown in the examples were measured as follows. The surface resistivity is high after applying the liquid mixture on a glass substrate by spin coating (rotation number: 16.67 s ⁻¹ / 10 seconds) and drying with a ventilator (150 ° C./30 minutes) to form a coated thin film. The surface resistivity of the coating film was measured using a resistivity meter (MCP-450 manufactured by Mitsubishi Chemical Corporation). The water contact angle is automatically contacted as a coating film by applying the mixture to a glass substrate (no adhesive) or a SUS substrate with a phenolic adhesive and drying (100 ° C / 60 minutes or 150 ° C / 30 minutes). It measured with the angle meter (Kyowa Interface Chemical Co., Ltd. Dms-400).

<Effect of metal species of metal oxide sol in fluororesin-metal oxide mixed dispersion>
Example 1
Fluororesin fine particle aqueous dispersion: A-1; 30 g
Metal oxide fine particle sol: B-1; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-titania mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 15 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 15 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 2)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-1; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-titania mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 15 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 15 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 3)
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-1; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-titania mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 15 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 15 days when used as a coating solution or impregnating solution for coating a fluororesin.
Example 4
Fluororesin fine particle aqueous dispersion: A-1; 30 g
Metal oxide fine particle sol: B-2; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-titania mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 5 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 5 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 5)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-2; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The pH of the prepared fluororesin-titania mixed dispersion is 4.8, and solidification gelation, aggregation precipitation, and phase separation are performed for 5 days or more when stored at room temperature. The viscosity did not change even after the storage test. Further, the fluidity was extremely good, and there was no problem even after 5 days when used as a coating solution or impregnating solution for coating a fluororesin.
The prepared fluororesin-titania mixed dispersion solution was used on a glass substrate (drying: 150 ° C./30 minutes) or a SUS substrate with a phenol-based adhesive (drying: 100 ° C./60 minutes or 150 ° C./30 minutes). The water contact angles of the coating films prepared in the above were 90.7 °, 105.3 ° and 102.9 °, respectively, which were considerably lower than the 130-140 ° of the fluororesin film PTFE membrane. The surface resistivity of the film prepared on the glass substrate (drying: 150 ° C./30 minutes) by spin coating is 6.9 × 10 ¹¹ Ω / □, and the fluororesin fine particle aqueous dispersion (A -2: The surface resistivity of the film obtained from Daikin Industries' polyflon D-111) was considerably smaller than 2.5 × 10 ¹² Ω / □.
(Example 6)
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-2; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-titania mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 5 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 5 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 7)
Fluororesin fine particle aqueous dispersion: A-1; 30 g
Metal oxide fine particle sol: B-3; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-zirconia mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 10 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 8)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-3; 24 g
Mixing conditions: room temperature, normal pressure stirring time: 30 minutes Result: The pH of the prepared fluororesin-zirconia mixed dispersion is 8.6, and solidification gelation, coagulation precipitation, and phase separation are performed for 10 days or more when stored at room temperature. The viscosity did not change even after the storage test. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
In addition, when the coating film was produced in the completely same procedure as the above-mentioned Example 5 using the prepared fluororesin-zirconia mixed dispersion liquid, the water contact angle was a glass substrate (drying: 150 ° C./30 minutes) or phenol. SUS substrate with an adhesive (drying: 100 ° C./60 minutes or 150 ° C./30 minutes) is 78.3 °, 104.8 ° and 99.3 °, respectively, and the surface resistivity of the film by spin coating is It was 2.6 × 10 ¹¹ Ω / □.
Example 9
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-3; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-zirconia mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 10 days or more in storage at room temperature, and after storage test The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 10)
Fluororesin fine particle aqueous dispersion: A-1; 30 g
Metal oxide fine particle sol: B-4; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-Lantana mixed dispersion is free from coagulation gelation, coagulation precipitation, and phase separation for 7 days or more after storage at room temperature. The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 11)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-4; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: pH of the prepared fluororesin-Lantana mixed dispersion is 9.2, and solidification gelation, coagulation precipitation, and phase separation are performed for 7 days or more when stored at room temperature. The viscosity did not change even after the storage test. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
When a coating film was prepared using the prepared fluororesin-lantana mixed dispersion in exactly the same manner as in Example 5 above, the water contact angle was glass substrate (drying: 150 ° C./30 minutes) or phenol. SUS substrate with an adhesive (drying: 100 ° C./60 minutes or 150 ° C./30 minutes) is 95.9 °, 122.8 ° and 121.4 °, respectively, and the surface resistivity of the film by spin coating is It was 2.5 × 10 ¹¹ Ω / □.
Example 12
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-4; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 30 minutes Result: The prepared fluororesin-Lantana mixed dispersion is free from coagulation gelation, coagulation precipitation, and phase separation for 7 days or more after storage at room temperature. The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 13)
Fluororesin fine particle aqueous dispersion: A-1; 30 g
Metal oxide fine particle sol: B-5; 9 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-neodymium oxide mixed dispersion is free from coagulation gelation, coagulation precipitation, and phase separation for 7 days or more after storage at room temperature. The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
(Example 14)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-5; 9 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-neodymium oxide mixed dispersion is free from coagulation gelation, coagulation precipitation, and phase separation for 7 days or more after storage at room temperature. The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.
In addition, when the coating film was produced in the completely same procedure as the above-mentioned Example 5 using the prepared fluororesin-neodymium oxide dispersion liquid, the water contact angle was a glass substrate (drying: 150 ° C./30 minutes) or phenol. The SUS substrate with an adhesive (drying: 150 ° C./30 minutes) was 82.6 ° and 115.2 °, respectively, and the surface resistivity of the film by spin coating was 2.8 × 10 ¹¹ Ω / □. It was.
(Example 15)
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-5; 9 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-neodymium oxide mixed dispersion is free from coagulation gelation, coagulation precipitation, and phase separation for 7 days or more after storage at room temperature. The viscosity was almost unchanged. Further, the fluidity was extremely good, and there was no problem even after 10 days when used as a coating solution or impregnating solution for coating a fluororesin.

  As can be seen from the above examples, any of the fluororesin fine particle aqueous dispersions is compatible with titania, zirconia, lantana and neodymium oxide sols, and a uniform mixed dispersion can be easily formed.

(Example 16)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-6; 10 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-ceria mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 3 days or more when stored at room temperature, and after storage test The viscosity was almost unchanged. Also, the fluidity was extremely good, and there was no problem even after 4 days when used as a coating solution or impregnating solution for coating fluororesin.
When a coating film was prepared using the prepared fluororesin-ceria mixed dispersion in exactly the same procedure as in Example 5 above, the water contact angle was glass substrate (drying: 150 ° C./30 minutes) or phenol. The SUS substrate with an adhesive (drying: 150 ° C./30 minutes) was 116.9 ° and 124.5 °, respectively, and the surface resistivity of the film by spin coating was 0.9 × 10 ¹¹ Ω / □. It was.
(Example 17)
Fluororesin fine particle aqueous dispersion: A-3; 30 g
Metal oxide fine particle sol: B-6; 10 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: The prepared fluororesin-ceria mixed dispersion does not cause coagulation gelation, coagulation precipitation, and phase separation for 3 days or more when stored at room temperature, and after storage test The viscosity was almost unchanged. Also, the fluidity was extremely good, and there was no problem even after 4 days when used as a coating solution or impregnating solution for coating fluororesin.
(Example 18)
Fluororesin fine particle aqueous dispersion: A-2; 30 g
Metal oxide fine particle sol: B-7; 24 g
Mixing conditions: room temperature and normal pressure stirring time: 60 minutes Result: pH of the prepared fluororesin-tin oxide mixed dispersion is 9.8, and coagulation gelation, coagulation precipitation, and phase separation for 3 days or more when stored at room temperature The viscosity did not change even after the storage test. Further, the fluidity was extremely good, and there was no problem even after 3 days when it was used as a coating solution or impregnating solution for coating a fluororesin.
In addition, when the coating film was produced in the completely same procedure as the above-mentioned Example 5 using the prepared fluororesin-tin oxide mixed dispersion, the water contact angle was a glass substrate (drying: 150 ° C./30 minutes) or SUS substrate with a phenol-based adhesive (drying: 100 ° C./60 minutes or 150 ° C./30 minutes), respectively, at 113.0 °, 121.1 ° and 126.6 °, and the surface resistivity of the film by spin coating Was 1.9 × 10 ¹¹ Ω / □.

  From Examples 16-18 described above, A-2 of the fluororesin fine particle aqueous dispersion has good compatibility with ceria and tin oxide, and a uniform mixed dispersion can be easily formed. In addition, A-3 of the fluororesin fine particle aqueous dispersion is compatible with ceria and can easily form a uniform mixed dispersion.

<Advantages of the invention>
As is clear from the above examples, it is clear that the metal oxide mixed with the fluororesin is effective in suppressing charging of the fluororesin and reducing the water contact angle, that is, improving / adjusting non-wetting and non-adhesiveness. became.

<Application and effect of the present invention>
According to the present invention, it is possible to suppress / control the charging of the fluororesin and to improve / improve its wettability and adhesiveness. This was confirmed in peeling by a cross-cut test of the coating film on the SUS substrate. That is, a coating film (see Example 5) formed by applying a fluororesin-titania mixed dispersion on a SUS substrate with a phenol-based adhesive, and a PTFE membrane attached to the same SUS substrate using the same adhesive. When the film was cut with a knife like a grid and peeled, it was confirmed that the former did not peel at all, but the latter easily and completely peeled off. This indicates that when a metal oxide such as titania is mixed in the fluororesin, its wettability and adhesiveness are remarkably improved.
Furthermore, it is also shown that the surface modification and treatment for higher functionality and multi-function of the fluororesin became possible by mixing metal oxide.
In addition, since the surface of soft fluororesin alone is soft, it can easily be damaged when it comes into contact with hard materials. However, the contamination of this type of metal oxide increases the hardness of the fluororesin and increases the heat resistance. It also has the effect of becoming a difficult surface.

The fluororesin-metal oxide mixed dispersion of the present invention is a coating liquid for coating on the surface of various materials such as metal, carbon, plastics, glass, ceramics, graphite, carbon fiber, carbonized fiber and the surface of products made of these materials. It is suitable as a fiber or powder impregnation liquid for the above materials.
Specifically, they are used as coating / coating materials for high functionality and multi-functionality of various materials and product surfaces such as electric wires, thermometers, various sensors, gaskets and packings.

Claims (5)

Aqueous fluorine obtained by mixing an aqueous dispersion of fluororesin fine particles with metal oxide fine particle sol having an appropriate pH value of any one of titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide and tin oxide. A resin-metal oxide mixed dispersion, wherein the fluororesin fine particles and the metal oxide fine particles are both suspended and dispersed without causing aggregation precipitation, gelation / coagulation and / or phase separation, and the suspended dispersion state is room temperature. The solid contact obtained by evaporating and scattering the solvent from this fluororesin-metal oxide mixed dispersion is 130 ° or less, and the surface resistivity is characterized by being stably maintained for 3 days or more during storage. A fluororesin-metal oxide mixed dispersion characterized by being 2.0 × 10 ¹² Ω / □ or less.   The appropriate pH value of the metal oxide fine particle sol is 2.5-13.5 for titanium oxide, 6.5-9 for zirconium oxide, 7-10 for lanthanum oxide, 7-10 for neodymium oxide, 6 for cerium oxide. The fluororesin-metal oxide mixed dispersion according to claim 1, which is 0.5 to 9.5 and 9 to 11 for tin oxide.   The fluororesin-metal oxide mixed dispersion is constituted by a weight ratio with respect to the content of the metal oxide fine particles in the dispersion, with the fluororesin fine particles being 3-100 times and water being 5-120 times. The fluororesin-metal oxide mixed dispersion according to claim 1 or 2.   An aqueous dispersion of fluororesin fine particles and a metal oxide fine particle sol having an appropriate pH value of any one of titanium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, and tin oxide, and 5-100 ° C. under normal pressure. 2. The composition is produced by mixing the fluororesin fine particles 3 to 100 times and water 5 to 120 times in a weight ratio with respect to the content of the metal oxide fine particles in the liquid at the temperature of 1. The manufacturing method of the fluororesin-metal oxide mixed dispersion liquid as described in any one of thru | or 3.   The appropriate pH value of the metal oxide fine particle sol is 2.5-13.5 for titanium oxide, 6.5-9 for zirconium oxide, 7-10 for lanthanum oxide, 7-10 for neodymium oxide, 6 for cerium oxide. The method for producing a fluororesin-metal oxide mixed dispersion according to claim 4, which is 0.5 to 9.5 or 9 to 11 for tin oxide.