JP5252612B2 - Resin composite composition and method for producing the same - Google Patents

Description

  The present invention relates to a resin composite composition in which inorganic fine particles are uniformly dispersed at a nano level in a resin and a method for producing the same.

Conventionally, there is a need for a resin composition having a higher performance in various fields, mechanical strength by dispersing a filler in a resin, dimensional stability, compressive creep characteristics, to improve such melt forming shape retention Things have been done.

  In particular, recently, many techniques have been made to improve the mechanical properties, heat distortion temperature, dimensional stability, etc. by directly melt-mixing nanoparticles such as inorganic fine particles into a polymer material. However, when inorganic fine particles or inorganic nanoparticles are melt-mixed with resin, the agglomeration force of the fine particles increases as the particle size decreases, causing reaggregation of the particles. It is extremely difficult to nano-disperse the material as it is (The 47th Japan Society for the Science Conference on Materials Research, Vol. 47, P150, 2003).

  As a method for coping with the problem of the direct melt mixing method, a solution mixing method is known in which a colloidal solution in which inorganic fine particles are stably dispersed and a resin aqueous dispersion are mixed. For example, an amorphous perfluoropolymer is formed in an organosol in which inorganic fine particles having an average particle diameter of 1000 nm or less treated with a fluorine-containing surface treatment agent are dispersed in an aprotic fluorine-containing solvent or a mixed solvent of this solvent and a protic fluorine-containing solvent. A dissolved composition (coating agent) has been proposed (Japanese Patent Application Laid-Open No. 2004-285361).

There has also been proposed an aqueous dispersion composition in which colloidal silica is treated with an organoalkoxysilane in advance and then mixed with a fluororesin polymer aqueous dispersion to improve storage stability (Japanese Patent Laid-Open No. 11-124534). coatings (paint) or mixture, that the surface treatment of the inorganic fine particles is required, also can not be obtained only a few hundred microns of film can not be obtained conventional compression, extrusion or injection molding products, etc. There was a problem.

  In addition, the surface stability of the inorganic fine particles improves the storage stability of the paint or mixed solution, but the coating obtained after drying and baking is uniform as in the paint or mixed solution before the inorganic fine particles are dried. Since it is not described whether it is dispersed or not, there is a possibility that re-aggregation between the inorganic fine particles may occur in the drying process after applying the paint.

  Another method for coping with the problem of this direct solution mixing method is an agglomerate formed from a mixed solution between different particles of colloidal silica and polystyrene emulsion containing potassium chloride (KCl) and adjusted to pH 5.6. Has been reported to form stable aggregates in which silica is uniformly dispersed only when the silica particle to resin primary particle size ratio is 3 or more (Colloid and Surface, vol. 63, P103, 1992). . However, the particle diameter of the colloidal silica used was 240 nm, and only the dispersion state and aggregation state of silica in the mixed solution were observed, and whether the silica particles were uniformly dispersed in the resin even after drying. It is not listed.

  In addition, hydrophobic modified hollow silica powder having a pore size of 0.1 to 50 nm modified with a hydrophobic modifier is added to the fluororesin emulsion, and after aggregation, drained and dried to improve hydrophobicity A hollow silica / fluororesin composite material has been proposed (Japanese Patent Laid-Open No. 2005-163006). However, this specification does not specify or describe the particle size and dispersion state of silica used, and silica powder is added to the fluororesin emulsion instead of colloidal silica. Moreover, from the figure of an Example, the particle diameter of hydrophobic modification | reformation hollow silica is 1000 nm or more.

  Furthermore, after adding silicon carbide particles having an average particle diameter of 4000 nm surface-treated with an aminosilane-based surface treatment agent to the fluororesin emulsion, nitric acid is added to destroy the fluororesin emulsion, and then trichlorotrifluoroethane is added. A method for agglomerating and granulating to obtain an agglomerated powder having an average particle diameter of 3 mm has been proposed (Japanese Patent Publication No. 7-64936). However, since silicon carbide powder having a particle diameter of 4 μm is added to the fluororesin emulsion, the powder is agglomerated.

JP 2004-285361 A Japanese Patent Laid-Open No. 11-124534 JP 2005-163006 A Japanese Patent Publication No. 7-64936

  In view of this, the present inventor has developed a resin emulsion (hereinafter sometimes referred to as latex) in which the resin primary particles are surrounded by a surfactant (hereinafter sometimes referred to as an emulsifier) and stably dispersed in a solvent, and the surface of the inorganic fine particles. The resin primary particles and inorganic fine particles are uniformly mixed by stirring a colloidal solution (hereinafter sometimes referred to as inorganic fine particle sol) in which multiple layers are formed and the inorganic fine particles are stably dispersed by the repulsive force between the inorganic fine particles. The aqueous dispersion is frozen at a temperature of 0 ° C. or lower, or an ionic strength or pH of the mixed solution is changed by adding an electrolytic substance, or a shearing force is applied to uniformly mix the resin primary particles and inorganic fine particles. After fixing the particles, it is possible to uniformly disperse the inorganic fine particles in the resin at the nano level by separating and drying the obtained particle aggregate from the aqueous solution. Focused on.

That is, the present invention, the inorganic fine particles are resin composite composition which is uniformly dispersed in the nano level in the resin, and to provide a manufacturing method thereof and then the resulting formed molded article.

The present invention relates to a resin emulsion comprising a polymer or copolymer of monomers selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride and vinyl fluoride. And an aqueous dispersion in which an inorganic fine particle colloidal solution having an average particle size of 5 to 500 nm is mixed with stirring, and an electrolytic substance is 0.001 to the total weight of the resin emulsion and the inorganic fine particle colloidal solution. the aggregate obtained by changing the ionic strength or pH of the mixture was added at a ratio of 15 wt%, to provide a method of manufacturing a tree fat composite composition and separating and drying the aqueous solutions .

  Production of the resin composite composition, wherein the colloidal solution of inorganic fine particles is a colloidal solution of at least one inorganic fine particle selected from silicon oxide, titanium oxide, aluminum oxide, a composite oxide in which zinc oxide and antimony pentoxide are combined. The method is a preferred embodiment of the present invention.

The method for producing a resin composite composition according to the present invention, wherein the colloidal solution of inorganic fine particles is a colloidal solution of inorganic fine particles containing 0.1 to 80% by weight of inorganic fine particles based on the weight of the solid component in the resin emulsion. a preferred embodiment der Ru.

  Average primary particle diameter in the resin emulsion (D _A ) And the average particle size of inorganic fine particles in a colloidal solution of inorganic fine particles (D _B ) (D) _B / D _A ) Is 0.1 or more is a preferred embodiment of the present invention.

Tree fat emulsion is a resin emulsion obtained by emulsion polymerization, the method for producing a resin composite composition is a preferred embodiment of the present invention.

  Moreover, this invention provides the resin composite composition obtained by the manufacturing method of the said resin composite composition.

In the parallel plate mode of the dynamic viscoelasticity measuring device, the viscosity at ₁ rad / sec (V ₁₎ measured at a temperature above the melting point in the case of a crystalline resin and at a temperature above the glass transition point in the case of an amorphous resin. ) And the viscosity (V _0.1 ) ratio (V _0.1 / V ₁ ) at _0.1 rad / sec can be 1.4 or more, the resin composite composition is a preferred embodiment of the present invention.

Storage elastic modulus at 200 ° C. of the resin composite composition is simple resin of 1.7 times or more, the resin composite composition Ru preferred embodiment der of the present invention.

Is found in the present invention provides a granulated powder obtained by granulating the resin composite composition.

  The present invention also provides a pellet obtained by melt-extruding the resin composite composition or the granulated powder of the resin composite composition.

The present invention provides a formed molded article comprising the resin composite composition.

The resin composite composition compression forming shapes, extruded formed shape, transfer formed shape, blow forming shapes, injection molding, rotational molding or lining formed shapes to formed molded product obtained is preferably a formed molded article of the present invention It is an aspect.

Tubing obtained by forming the shape of the resin composite composition, sheets, rods acids, fibers, packings such, linings such, wire coating such or sealing ring compound is a preferred embodiment of the formed molded article of the present invention is there.

  According to the present invention, a resin composite composition in which inorganic fine particles are uniformly dispersed at a nano level in a resin can be obtained.

The present invention provides a resin composite composition in which inorganic fine particles are uniformly dispersed at a nano level in a resin and a method for producing the same.
The resin in the resin emulsion used in the present invention is not particularly limited, and those already known widely can be used. For example, as the fluororesin in the fluororesin emulsion, tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), trifluoroethylene, hexafluoropropylene (HFP), perfluoro (alkyl vinyl ether) (PAVE), etc. or copolymers of monomers selected from vinylidene fluoride (VdF) and vinyl fluoride (VF) and the like.

Specific examples of the fluorine-containing resin include polytetrafluoroethylene (hereinafter referred to as PTFE), TFE / PAVE copolymer (hereinafter referred to as PFA), TFE / HFP copolymer (hereinafter referred to as FEP), TFE / HFP / PAVE copolymer (EPE), Po Li vinylidene fluoride (PVdF), polychlorotrifluoroethylene (PCTFE), TFE / VdF copolymer, TFE / VF copolymer, TFE / HFP / VF copolymer HFP / VdF copolymer, VdF / CTFE copolymer, TFE / VdF / CTFE copolymer, TFE / HFP / VdF copolymer, and the like.

  In the copolymer (PFA) of tetrafluoroethylene and perfluoro (alkyl vinyl ether), the alkyl group of perfluoro (alkyl vinyl ether) preferably has 1 to 5 carbon atoms, particularly 1 to 3 carbon atoms.

  The resin emulsion (dispersion liquid) of these polymers and copolymer particles is usually preferably produced by emulsion polymerization.

In the present invention, the resin primary particles surrounded by the surfactant and the colloidal solution in which the inorganic fine particles are stably dispersed are stirred and the resin primary particles and the inorganic fine particles are uniformly dispersed. After mixing, the stability of the resin emulsion or inorganic fine particle colloid solution is suddenly lowered, and the uniform structure of the resin primary particles and inorganic fine particles is fixed. etc. the melting point Ru can be obtained resin composite composition in which the inorganic fine particles regardless is uniformly dispersed in the nano level in the resin.

The particle size of the resin primary particles in the tree fat emulsion, depending on the particle size of the inorganic fine particles in the colloidal solution to be used, for example 50 to 500 nm, preferably from 70 to 300 nm.

In the present invention, a sol in which inorganic fine particles are stably dispersed is used. Examples of the inorganic fine particles of the sol include silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), zeolite, zirconium oxide (ZrO ₂ ), and alumina. (Al ₂ O ₃ ), zinc oxide (ZnO), and antimony pentoxide are preferable. Further, depending on the purpose, they may be used alone or in combination, or the above or other fine particles may be selected and used in combination. Other fine particles include silicon carbide (SiC), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), barium titanate (BaTiO ₃ ), boron nitrite, lead oxide, tin oxide, chromium oxide, hydroxide Examples thereof include fine metal particles such as chromium, cobalt titanate, cerium oxide, magnesium oxide, cerium zirconate, calcium silicate, zirconium silicate, gold, silver, copper, and transition metals.

  The inorganic fine particle sol of the present invention is preferably stabilized in a solution state with various electrolytes, organic additives and the like. For example, a colloidal silica sol is a colloidal solution in which negatively charged silicon oxide nanoparticles are dispersed in water. Silanol groups and hydroxyl groups are present on the surface of the particles, and an electric double layer is formed by alkali ions. Stabilized by repulsion between particles.

  The particle size of the inorganic fine particles in the sol is not particularly limited as long as it can be obtained as a raw material sol, and is usually an average particle size of 1 to 1000 nm, preferably 5 to 500 nm, more preferably 10 to 500 nm. In general, a sol having inorganic fine particles having an average particle size in the range of 5 to 500 nm is easily available, and the average particle size is 10 to 400 nm for the purpose of obtaining physical properties that can be expected by uniformly dispersing the inorganic fine particles at the nano level. Particularly preferred are inorganic fine particle sols having these inorganic fine particles. In general, when the particle diameter of the inorganic fine particles is 500 nm or more, the inorganic fine particles are precipitated, and the storage stability of the colloidal silica sol is deteriorated.

  In the present invention, the resin primary particles are surrounded by a surfactant by emulsion polymerization, and an electric double layer is formed on the surface of the inorganic fine particles and the resin emulsion stably dispersed in the solvent, and is stably dispersed by the repulsive force between the inorganic fine particles. It is necessary to agitate the inorganic fine particle sol and uniformly mix the resin primary particles and the inorganic fine particles, and then fix the uniform mixed state of the resin primary particles and the inorganic fine particles at once (hereinafter sometimes referred to as co-aggregation). ).

  As a method of aggregating the mixed solution between different kinds of particles, the resin emulsion and the inorganic fine particle sol mixed solution are agitated with a strong shearing force by a stirrer, and the micelle structure of the surfactant in the fluororesin emulsion is destroyed and agglomerated. Method (physical agglomeration), a method of agglomerating by suddenly reducing the stability of resin emulsion or inorganic fine particle colloid by changing the ionic strength or pH by adding electrolytic substance to resin emulsion and inorganic fine particle sol mixed solution (chemical) And a method in which colloidal particles are pressed and aggregated between ice crystals by the growth of ice crystals generated by freezing the resin emulsion and the inorganic fine particle sol mixed solution (freeze aggregation). Among these, an electrolytic substance or an inorganic salt is added to the mixed solution of the resin emulsion and the inorganic fine particle sol to rapidly reduce the stability of the resin emulsion or the inorganic fine particle colloid solution, and the resin primary particles and the inorganic fine particles are uniformly mixed at once. A chemical aggregation method is preferred in which the state is fixed to obtain an aggregate in which different types of particles are uniformly dispersed.

Used for the purpose of chemically agglomerating fluororesin primary particles in an aqueous fluororesin dispersion, for example, depending on the type and proportion of the resin primary particles or inorganic fine particles in the mixed liquid before chemical agglomeration Electrolytic substances include inorganic or organic water-soluble HCl, H ₂ SO ₄ , HNO ₃ , H ₃ PO ₄ , Na ₂ SO ₄ , MgCl ₂ , CaCl ₂ , sodium formate, potassium acetate, ammonium carbonate, etc. The compound of can be illustrated. Among these, it is preferable to use a compound that can be volatilized in the subsequent drying step of the aggregate, such as HCl, HNO ₃ , (NH ₄ ) ₂ CO _{3, and the} like.

In addition to the above electrolytic substances, halogen metal, phosphoric acid, sulfuric acid, molybdic acid, nitric acid alkali metal salt, alkaline earth metal salt, ammonium salt, etc., preferably potassium bromide, potassium nitrate, potassium iodide (KI) Inorganic salts such as ammonium molybdate, sodium dihydrogen phosphate, ammonium bromide (NH ₄ Br), potassium chloride, calcium chloride, copper chloride, calcium nitrate can be used alone or in combination. By eluting the residual inorganic salt repeatedly using pure water, the inorganic salt can be removed.

The amount of these electrolytic substances used depends on the type of the electrolytic substance and the solid content concentration of the resin emulsion and the inorganic fine particle sol, but is 0.001 to 15% by weight based on the weight of the mixed solution of the resin emulsion and the inorganic fine particle sol. In particular, it is preferably used in a proportion of 0.05 to 10% by weight. Further, it is preferably added to the resin emulsion and sol mixed solution in the form of an aqueous solution. When the amount of electrolyte used is too small, there is a place where the agglomeration occurs partly slowly, so that the uniform mixing state of the resin primary particles and the inorganic fine particles cannot be fixed all at once. There are cases where a resin composite composition uniformly dispersed therein cannot be obtained.
Depending on the solid content concentration of the resin emulsion and the inorganic fine particle sol, the resin emulsion or the inorganic fine particle sol is previously diluted with pure water for the purpose of stirring the resin emulsion and the inorganic fine particle sol to obtain a uniform mixed solution. It is also possible to stir and mix after adjusting the solid content concentration.

  There is no particular limitation on the device for stirring the resin emulsion and the inorganic fine particle sol to uniformly mix the resin primary particles and the inorganic fine particles, and then mixing and co-aggregating with an electrolytic substance or an inorganic salt. However, it is preferable that the apparatus includes a stirring means capable of controlling the stirring speed, for example, a propeller blade, a turbine blade, a paddle blade, a paddle blade, a horseshoe blade, a spiral blade, and a drainage device.

  The resin emulsion, inorganic fine particle sol and electrolytic substance or inorganic salt are placed in such an apparatus and stirred, whereby the resin colloidal particles or / and the inorganic fine particles are aggregated to form aggregates of different particles and separated from the aqueous medium. . The stirring speed in the step of separating the aqueous medium from the aggregate is preferably 1.5 times faster than the stirring speed in the mixing step of the resin emulsion and the inorganic fine particle sol. The agglomerates of different kinds of particles are discharged with an aqueous medium and washed with water as necessary, and then dried at a temperature not higher than the melting point of the resin or the thermal decomposition starting temperature, whereby a powder of the resin composite composition is obtained. The drying temperature is preferably a temperature at which the electrolytic substance, the surfactant and the like can be volatilized below the temperature at which the resin does not undergo thermal degradation or decomposition.

  The ratio of the inorganic fine particles in the inorganic fine particle sol to the resin solid component of the resin emulsion is 0.1 to 80% by weight, more preferably 0.3 to 50% by weight, although it depends on the use of the resin composite composition. Preferably it is 0.5-30 weight%. A nano-resin composite mixture in which inorganic fine particles are dispersed at a nano level in a resin or a so-called polymer nano-composite is between a nano particle and a resin matrix compared to a conventional resin composite mixture in which a filler is dispersed at a micron level. Since the interface area greatly increases, there is an advantage that improvement in physical properties can be expected with a smaller amount of inorganic fine particles than the conventional resin composite mixture. In addition, when inorganic fine particles having a particle diameter smaller than the wavelength of visible light are uniformly dispersed at the nano level, the resin nanocomposite may become transparent or translucent.

The present invention in which the resin emulsion and the sol in which the inorganic fine particles are dispersed are stirred to uniformly mix the resin primary particles and the inorganic fine particles, and then aggregate to fix the resin primary particles and the inorganic fine particles in a uniform mixed state. One of the characteristics of the resin composite mixture is that the inorganic fine particles are uniformly dispersed at the nano level in the resin, so that the conventional resin composite mixture filled with inorganic particles having a size of several thousand nm or more Is to show different viscoelastic behavior.

  A general polymer concentrated solution or melt is a typical non-Newtonian fluid, and changes depending on the viscosity shear rate. When the shear rate increases, the viscosity decreases, and when the shear rate decreases, the viscosity decreases. To increase. However, as the shear rate is further reduced, it gradually approaches a constant value. This limit value is called zero shear rate viscosity (Zero Shear Rate Viscosity), one of the most important physical quantities representing the viscosity of a polymer, and is expressed by an exponential function of molecular weight.

For example, normally, the melt viscosity of the melt processible fluoropolymer is close to constant and is shear rate decreases, showing a Newtonian fluid behavior (A in Figure 1). In addition, the conventional resin composite mixture in which fused silica having a particle size of about 30000 nm is dispersed in a heat-melting fluororesin also has a viscosity that is higher at a substantially constant rate compared to a heat-melting fluororesin that does not contain silica. However, when the shear rate becomes small, the value approaches a constant value and shows a behavior like a Newtonian fluid (B in FIG. 1). However, the heat-meltable fluororesin composite of the present invention in which silica having a particle diameter of about 66 nm is uniformly dispersed in the heat-meltable fluororesin does not have a melt viscosity that approaches a constant value even when the shear rate is reduced. However, when the shear rate is decreased, the viscosity is further increased (C and D in FIG. 1).

  The zero shear viscosity of the resin composite mixture of the present invention is further increased when the shear rate is reduced. The nanoresin composite mixture in which inorganic fine particles are dispersed at a nano level in a resin or a so-called polymer nanocomposite has a filler. Compared to the conventional resin composite mixture dispersed at the micron level, the activity of the nanoparticle surface is significantly increased, the interface area between the nanoparticle and the resin matrix is greatly increased, and the nanodispersion is more uniform. The reason seems to be that the distance between the nanoparticles is shorter than that of the conventional resin composite mixture in which the filler is dispersed at the micron level. If the same amount of 70 nm diameter silica is completely nano-dispersed in the resin instead of silica having a diameter of about 30000 nm, the surface area of the silica or the interface area with the resin will increase by about 400 times.

  Such a significant increase in the surface activity and surface area or interfacial property of the nanoparticle is characteristic of polymer nanocomposites in which inorganic fine particles are dispersed at the nano level in a resin, which is smaller than conventional resin composite mixtures. This is the reason why improvement in physical properties can be expected with the inorganic fine particles. For example, the heat-meltable fluororesin composite in which the inorganic nanoparticles of the present invention are uniformly dispersed at the nano level has a higher viscosity when the shear rate is reduced, so that when a fire occurs in a resin product such as an electric wire. It can be used for applications where high-temperature droplets are difficult to fall off (drip prevention).

  In addition, the dispersion state of the nanoparticles dispersed in the resin can be observed directly with a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It is necessary to observe at a very high magnification, only a very local portion can be observed, and it is difficult to examine the dispersion state of the nanoparticles in the entire sample. However, it is also possible to indirectly evaluate the dispersion state of the nanoparticles by examining the change in viscosity when the shear rate is low.

In the case of a heat-meltable fluororesin composite obtained by stirring and mixing a resin emulsion and an inorganic fine particle sol in which inorganic fine particles are dispersed, and then agglomerating, use the parallel plate mode of the dynamic viscoelasticity measuring device. In the case of a crystalline resin, the viscosity at ₁ rad / sec (V ₁ ) and the viscosity at _0.1 rad / sec (V _0.1 ) are measured at a temperature above the melting point in the case of a crystalline resin and at a temperature above the glass transition point in the case of an amorphous resin. ) Ratio (V _0.1 / V ₁ ) depends on the mixing ratio of the resin primary particles and the inorganic fine particles and the particle diameter of the inorganic fine particles, but is 1.4 or more, preferably 1.5 or more, more preferably 2. It is desirable that it is 0 or more. That is, the ratio of the viscosity (V _0.1 / V _1), in the measurement in a temperature of at least one point of the temperature, it is desirable that satisfy the ratio of the viscosity (V _0.1 / V _1).
The measurement in the parallel plate mode of the dynamic viscoelasticity measuring apparatus is performed at a temperature higher than the melting point of the resin and lower than the decomposition temperature in the case of a crystalline resin, and at a temperature higher than the glass transition point and lower than the decomposition temperature in the case of an amorphous resin. It is preferable. For example, in the case of PTFE or PFA which is a crystalline resin, 340 ° C. may be mentioned, and in the case of FEP, 280 ° C. may be mentioned. In the case of PS which is an amorphous resin, 130 ° C. is exemplified, and in the case of PVA, 80 ° C. is exemplified.

The resin primary particle size in the resin emulsion and the particle size of the inorganic fine particles in the inorganic fine particle sol depend on the mixing ratio of the resin primary particles and the inorganic fine particles, but the resin primary particle size (D _A ) and the particle size of the inorganic fine particles. _{(D B)} of the ratio _(D B / D _a) is 0.1 or more, preferably from 0.35 to 2.0. If the particle size of the inorganic fine particles is too small, the resin primary particles are agglomerated with each other and cannot be aggregated together, resulting in an aggregate in which the inorganic fine particles are dispersed unevenly. there is a possibility. Further, if the particle size of the inorganic fine particles is too large, only the inorganic fine particles tend to settle out in the mixed liquid with the inorganic fine particle sol or the resin emulsion.

In the present invention, the dry powder dry heterologous resin primary particle and the inorganic particles obtained by the process are uniformly dispersed particles, extruded formed shape after the pellets through a conventional melt extruder, injection molding, transfer formed it can be melt formed form such shapes. Of course, either directly formed form raw material powder of the aggregate of the pelleted not other particles as in the previous year, or at compactors order to improve the bite of the powder aggregates formed form machine hopper hardened agglomerates melting adult It can also be shaped . In the dry powder sample of the agglomerate and the sample pelletized through a melt extruder, the dispersion state of the inorganic fine particles dispersed in the resin is almost the same. Nano-dispersed inside. Furthermore, aggregate further granulated to powder formed shapes and powder coating of heterogeneous particles resin primary particle and the inorganic particles obtained in the present invention are uniformly dispersed, can be used as a rotation molding material.

Moreover, when making a pellet through a melt extruder, it is preferable to use a biaxial extruder from the surface of a shear stress. By changing the screw configuration and rotational speed of the twin screw extruder, the inorganic fine particles can be further uniformly dispersed in the hot melt. However, in addition to the purpose of pelletizing, it does not necessarily mean that melt mixing is necessary for uniform dispersion of inorganic fine particles or improvement of physical properties. Further, in the process of pelletizing through a melt extruder, additives can be optionally blended or blended with other resins. The blending of the additive can be performed not only in the melt extrusion process but also in the coagulation process of the mixed liquid composed of the resin emulsion and the inorganic fine particle sol. Examples of such additives include glass fiber, carbon fiber, aramid fiber, graphite, carbon black, mica, clay, fullerene, carbon nanotube, and carbon nanofiber. In particular, since layered silicon compounds such as mica and clay can be stably dispersed even in an aqueous solvent, they can be mixed together as an aqueous dispersion in the mixing step of the resin emulsion and the inorganic fine particle sol.

  The type of the molded product to be finally produced is not particularly limited, and can be applied to any field where improvement of the effect can be expected by uniformly dispersing the particles in the resin at the nano level. For example, there are tubes, sheets, films, rods, fibers, packings, linings, seal rings, electric wire coating, printed circuit boards, and the like. In particular, since a resin composite composition in which inorganic fine particles having a particle diameter of 100 nm or less are uniformly dispersed in a resin matrix to a nano level becomes transparent or translucent, an antireflection coating film, a scratch resistant film, and an optical fiber manufacture It is useful for various applications such as materials, transparent films, transparent tubes, and electronic materials. Furthermore, if the particles are uniformly dispersed in the resin at the nano level, the zero shear viscosity when the shear rate is very low is much higher than when the particles are not nano-dispersed. It can also be used for applications where high temperature droplets are difficult to fall off when drip occurs (anti-drip).

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.
In the present invention, physical properties were measured by the following methods.

(A. Measurement of physical properties)
(1) Melting point (melting peak temperature)
A differential scanning calorimeter (Pyris 1 type DSC, manufactured by Perkin Elmer) was used. About 10 mg of a sample is weighed and placed in a dedicated aluminum pan, crimped by a dedicated crimper, stored in the DSC body, and heated from 150 ° C. to 360 ° C. at a rate of 10 ° C./min. The melting peak temperature (Tm) was determined from the melting curve obtained at this time.

(2) Melt flow rate (MFR)
Using a melt indexer (manufactured by Toyo Seiki Co., Ltd.) equipped with a corrosion-resistant cylinder, die, and piston according to ASTM D-1238-95, 5 g of sample powder is filled into a cylinder held at 372 ± 1 ° C. After holding for 5 minutes, extrusion was performed through a die orifice under a load of 5 kg (piston and weight), and the extrusion speed (g / 10 minutes) at this time was determined as MFR. For PTFE, because the higher molecular weight can not be conventional melt formed shape, the measurement of the melt flow rate was not carried out.

(3) Particle size The primary particle size of the resin in the fluororesin emulsion and the silica particle size in the silica sol were applied to an aluminum foil by applying a fluororesin emulsion or silica sol diluted with pure water to a concentration of 5% by weight and dried. The particles on the sample surface thus obtained were observed with an electron microscope, and the average particle size was determined.

(4) Silica dispersion state Three pieces of 10 mm × 10 mm specimens were cut out from a sheet-like sample having a thickness of about 200 μm prepared by melt compression molding a fluororesin composite composition sample at 350 ° C., and an optical microscope (NIKON (Manufactured by OPTIPHOT2-POL), the dispersion state was evaluated for the presence of aggregates composed of silica nanoparticles having a size of 1000 nm or more.

  Only for samples in which aggregates composed of silica nanoparticles of 1000 nm or more were not observed, the fracture surface prepared in liquid nitrogen was observed at three locations for each sample with an electron microscope, and the silica dispersion state was evaluated. When observed with an electron microscope, the case where most of the silica is dispersed to the primary particles is indicated by 場合, the case where a few aggregates composed of silica nanoparticles remain is indicated by ◯, and the silica nanometer of 1000 nm or more is observed with an optical microscope. The case where many agglomerates composed of particles remain is indicated by crosses.

(5) Zero Shear Rate Viscosity
A test specimen having a diameter of 25 mm was prepared from a sheet-like sample having a thickness of about 1.5 mm produced by melt compression molding a resin composite composition sample at 350 ° C., and 25 mm parallel of an ARES viscoelasticity measuring apparatus manufactured by Rheometric Scientific. Using a plate, the melt viscosity was measured at a frequency (shear rate) of 100 to 0.1 rad / sec at 340 ° C., and the viscosity at ₁ rad / sec (V ₁ ) and the viscosity at _0.1 rad / sec (V _0.1 ). Ratio (V _0.1 / V ₁ ) was calculated.

(6) Storage elastic modulus A 12 mm x 45 mm x 1.5 mm sample piece was made from a sheet-like sample having a thickness of about 1.5 mm produced by melt-compression molding a resin composite composition sample at 350 ° C, and Rheometric Scientific Using an ARES viscoelasticity measuring device manufactured by KK, Torsion Mode was measured at 1 Hz, from −40 ° C. to 200 ° C. at a heating rate of 5 ° C./min.

(B. Raw material)
The raw materials used in Examples and Comparative Examples of the present invention are as follows.
(1) PFA aqueous dispersion obtained by emulsion polymerization of PFA emulsion (PFA solid content: 30% by weight, average particle diameter of PFA primary particles: 200 nm,
(pH: 9, melting point: 309 ° C., melt flow rate: 2 g / 10 min)
(2) PFA pellets (melting point: 309 ° C., melt flow rate: 2 g / 10 min)
(3) PTFE emulsion PTFE aqueous dispersion obtained by emulsion polymerization (solid content: 50% by weight, average particle size of primary particles: 210 nm, pH: 9, melting point: 326 ° C.)

(4) Silica sol (a) Made by Nissan Chemical Co., Snowtex MP2040
(Silica: 40% by weight, silica primary particle size: 190 nm, pH: 9.5)
(B) Made by Nissan Chemical Co., Snowtex MP1040
(Silica: 40% by weight, silica primary particle size: 110 nm, pH: 9.5)
(C) Fuso Chemical, PL-7
(Silica: 23% by weight, silica primary particle size: 70 nm, pH: 7.4),
(D) PL-3, manufactured by Fuso Chemical
(Silica: 20% by weight, silica primary particle size: 35 nm, pH: 7.2)
(5) Fused silica, FB-74, manufactured by Denki Kagaku Kogyo
(Silica average particle size: 32000 nm)

Example 1
After putting 33 g of Nissan Chemical's silica sol (MP-2040) and 1000 g of pure water into a beaker (2 L) and stirring for 20 minutes at 200 rpm using a downflow type propeller type four-blade stirrer, the silica content is PFA. Add 853 g of PFA aqueous dispersion obtained by emulsion polymerization to 5% by weight with respect to the resin composite, and after stirring for 20 minutes, add 9 ml of 60% nitric acid, and gelation proceeds and stirring becomes impossible. While stirring until the fluororesin primary particles and silica nanoparticles were agglomerated at once. The resulting gel-like aggregate was further stirred at 350 rpm for 5 minutes. The aggregate was separated from the aqueous medium to remove excess water, and then the remaining aggregate was dried at 150 ° C. for 10 hours to obtain a dry powder of the aggregate Got. The dry powder of the agglomerates was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and optical / electron microscope observation. The results are shown in Table 1 and FIG. Show.

(Example 2)
Aggregate dry powder was prepared in the same procedure as in Example 1 except that the amount of silica sol and PFA aqueous dispersion was adjusted so that the silica content was 15 wt% with respect to the PFA resin composite. The dry powder of the aggregate was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and observation with an optical / electron microscope. The results are shown in Table 1.

(Example 3)
Aggregate dry powder was prepared in the same procedure as in Example 1 except that the amount of silica sol and PFA aqueous dispersion was adjusted so that the silica content was 20 wt% with respect to the PFA resin composite. The dry powder of the agglomerate was compression molded at 350 ° C., and the elastic modulus / viscosity measurement and optical / electron microscope observation were performed using the obtained sheet-like sample having a thickness of about 1.5 mm. The results are shown in Table 1 and FIG. Of C.

Example 4
Aggregate dry powder was prepared in the same procedure as in Example 1 except that the silica sol was PL-7 instead of MP-2040 and the silica content was 10 wt% with respect to the PFA resin composite. The dried aggregate powder was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and optical / electron microscope observation. The results are shown in Table 1 and FIG. E, shown in FIG. Further, in order to observe the dispersion state of the PFA primary particles and the silica particle mixture before compression molding the obtained dry powder of the aggregate by observation with a high magnification electron microscope, the dry powder of the aggregate is further reduced to 12 at 295 ° C. FIG. 5 shows an electron microscope of the dried powder of the aggregate that was dried for a while and the surfaces of the PFA primary particles were slightly welded.

(Example 5)
Aggregate dry powder was prepared in the same procedure as in Example 4 except that the silica content was 20 wt% (PL-7) based on the PFA resin composite. The dry powder of the agglomerate was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and observation with an optical / electron microscope. The results are shown in Table 1 and FIG. D and D in FIG.

(Example 6)
Aggregate dry powder was prepared in the same procedure as in Example 1 except that the silica sol was changed to PL-3 instead of MP-2040 and the silica content was 20 wt% with respect to the PFA resin composite. The dry powder of the aggregate was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and observation with an optical / electron microscope. The results are shown in Table 1.

(Example 7)
This is an example using PTFE that cannot be melt-molded. The same procedure as in Example 1 except that an aqueous PTFE dispersion was used instead of the aqueous dispersion, pure water was added to make the PTFE solid content 30% by weight, and the silica content was 5% by weight based on the resin composite. A dry powder of the aggregate was prepared and the viscosity was measured. The results are shown in Table 1. Since PTFE has an extremely high melt viscosity, viscosity measurement was not performed. The dried aggregate powder was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was observed with an optical / electron microscope. The results are shown in Table 1 and FIG.

(Comparative Example 1)
Fused silica with an average particle size of 32000 nm and PFA pellets, which are heat-meltable resins, are melt-mixed at 340 ° C. and 100 rpm for 5 minutes using a melt mixing device (R-60 mixer, manufactured by Toyo Seiki Co., Ltd.). Obtained a conventional composite composition in which 32000 nm of silica was dispersed in a heat-meltable fluororesin. The obtained sample was compression-molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and observation with an optical / electron microscope. The results are shown in Table 1 and FIG. Shown in

(Comparative Example 2)
This is an example of a film formed by directly applying a liquid mixture of a fluororesin aqueous dispersion and silica sol to a substrate without agglomeration. It is obtained by emulsion polymerization after putting 33g of Nissan Chemical's silica sol (MP-1040) and 1000g of pure water into a beaker (2L) and stirring at 200rpm for 20 minutes using a downflow type propeller type four-blade stirrer. In addition, 853 g (silica: 5% by weight) of PFA aqueous dispersion was added and stirred for 20 minutes to obtain a mixed liquid of fluororesin aqueous dispersion and silica sol. The mixed solution was directly spray-coated on an aluminum plate, dried at 120 ° C. for 30 minutes, and further baked at 350 ° C. for 15 minutes to obtain a coating having a thickness of about 50 μm. The surface of this coating was observed with an optical / electron microscope, and the results are shown in Table 1 and FIG.

(Comparative Example 3)
In this example, the mixture of the fluororesin aqueous dispersion and the silica sol is dried as it is without agglomerating. A mixed solution of an aqueous fluororesin dispersion having a silica content of 10% by weight and silica sol was obtained in the same manner as in Example 4 except that the silica sol was changed to MP-1040 instead of MP-2040. The mixed solution was dried at 80 ° C. for 12 hours to prepare a dry powder. The dry powder of the aggregate was compression molded at 350 ° C., and the obtained sheet-like sample having a thickness of about 1.5 mm was subjected to elastic modulus / viscosity measurement and optical / electron microscope observation. The results are shown in Table 1 and FIG. Show.

(Reference Example 1)
The physical properties of only the heat-meltable fluororesin are shown in Table 1, A in FIG. 1, and A in FIG.

In Example 1, Example 2, and Example 3, the silica nanoparticles were completely nano-dispersed in the hot-melt fluororesin matrix. Due to the nano-dispersed silica, the viscosity ratio (V _0.1 / V ₁ ) is higher than that of pure heat-meltable fluororesin (Reference Example 1), and the viscosity ratio (V _0.1 / V ₁ ) increases with increasing silica content. became. Moreover, the storage elastic modulus became high with the increase in the amount of silica.

In Examples 4 and 5, the silica nanoparticles were completely nano-dispersed in the hot-melt fluororesin matrix. Further, when samples having the same silica content of 20% were compared, the viscosity ratio (V _0.1 / V ₁ ) of Example 5 having a smaller silica particle size was larger than that of Example 3. In particular, in Example 5, the PFA primary particles (average particle size: about 200 nm) and the silica particles (average particle size: about 70 nm) before compression-molding the dry powder of the aggregate were also aggregated from the surface of the mixture. No aggregates of silica particles were observed.

In Example 6, even when the particle diameter of the silica was 35 nm, the silica nanoparticles were completely nano-dispersed in the heat-meltable fluororesin matrix. In addition, although there was no aggregate composed of silica nanoparticles having a size of 1000 nm or more from observation with an optical microscope, the size was about several hundreds of nanometers composed of silica particles having a particle diameter of 35 nm when observed at 20,000 times with an electron microscope. Slight aggregation was observed. The viscosity ratio (V _0.1 / V ₁ ) was almost the same as that of Example 5 having a particle size of 70 nm and a silica content of 20%.

From Example 3, Example 5, and Example 6, when the amount of silica was 20% by weight, the storage modulus increased as the particle size of silica decreased.
In Example 7, since PTFE usually has a high melt viscosity, silica nanoparticles were completely nano-dispersed in the heat-meltable fluororesin matrix even in PTFE, which is difficult to melt and mix with fillers and fine particles.

In Comparative Example 1, since it is a conventional composite composition in which silica having an average particle size of 32000 nm is dispersed in a heat-meltable fluororesin, the viscosity ratio (V _0.1 / V ₁ ) is a heat without silica. It is almost the same as a meltable fluororesin. This is because silica is not nano-dispersed.

  In Comparative Example 2, in the film obtained by directly applying the mixture of the fluororesin aqueous dispersion and silica sol to the base material without agglomeration, separation between the fluororesin primary particles and the silica nanoparticles during the drying of the mixture Aggregation occurred, and many aggregates of silica nanoparticles having a size of several μm were observed on the film surface after firing.

Therefore, it can be seen that the silica nano-dispersion cannot be achieved simply by drying without mixing the mixed liquid of the fluororesin aqueous dispersion and the silica sol. In order to nano-disperse silica, it is necessary to agglomerate a mixture of a fluororesin aqueous dispersion and silica sol to fix a uniform mixed state of resin primary particles and inorganic fine particles at once.
In Comparative Example 3, since the liquid mixture of the fluororesin aqueous dispersion and the silica sol was dried as it was without agglomeration, aggregates of silica nanoparticles were observed.

In the present invention, even if the inorganic fine particles are not subjected to a surface treatment, the resin primary particles are surrounded by the surfactant and the electric double layer is formed on the surface of the inorganic fine particles and the resin fine particles are stably dispersed in the solvent. by stirring the colloidal solution in which the inorganic fine particles are stably dispersed by a force, changing the ionic strength or pH of the aqueous dispersion were uniformly mixed resin primary particles and inorganic fine particles, a mixture by adding electrolytic material after fixing the uniform mixed state of the resin primary particle and the inorganic fine particles in the Turkey is, the resulting agglomerates of particles uniformly to the nano-level fine inorganic particles and the resin primary particles by separating and drying from aqueous solutions A mixed / dispersed resin composite composition can be obtained. Therefore, the resin composite composition provided by the present invention can be applied to a wide range of fields because the inorganic fine particles are uniformly dispersed at the nano level.

  Furthermore, the molded article produced from the resin composite composition provided by the present invention can be applied to a wide range of fields because the particles are uniformly dispersed at the nano level in the resin. Specific examples of applications include tubes, sheets, films, rods, fibers, packings, linings, seal rings, electric wire coating, printed circuit boards, and the like.

  In particular, a resin composite composition in which inorganic fine particles having a particle diameter of 350 nm or less are uniformly dispersed in a resin matrix becomes transparent or translucent, and therefore, an antireflection coating film, a scratch-resistant film, and an optical fiber manufacture It is useful for various applications such as materials, transparent films, transparent tubes, and electronic materials.

  Furthermore, if the particles are uniformly dispersed in the resin at the nano level, the zero shear viscosity when the shear rate is very low is much higher than when the particles are not nano-dispersed. It can also be used for applications where high temperature droplets are difficult to fall off when drip occurs (anti-drip).

It is a zero shear viscosity measurement result of a heat-meltable resin composite composition (silica 20% by weight). It is a zero shear viscosity measurement result of the heat-meltable resin composite composition using PL-7. The electron micrograph of the torn surface of the heat-meltable fluororesin composite composition sample used in Example 1. The electron micrograph of the torn surface of the heat-meltable fluororesin composite composition sample used in Example 4. The electron micrograph of the surface of the dry powder of the aggregate used in Example 4. FIG. The electron micrograph of the torn surface of the heat-meltable fluororesin composite composition sample used in Example 7. The electron micrograph of the surface of the heat-meltable fluororesin composite composition sample used in Comparative Example 2. The electron micrograph of the fracture surface of the heat-meltable fluororesin composite composition sample used in Comparative Example 3.

Claims (13)

Resin emulsion consisting of a polymer or copolymer of monomers selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, perfluoro (alkyl vinyl ether), vinylidene fluoride and vinyl fluoride, and average particles In an aqueous dispersion obtained by mixing a colloidal solution of inorganic fine particles having a diameter of 5 to 500 nm with stirring, the electrolytic substance is added in an amount of 0.001 to 15% by weight based on the total weight of the resin emulsion and the inorganic fine particle colloidal solution. A method for producing a resin composite composition, characterized in that an aggregate obtained by changing the ionic strength or pH of a mixed solution by adding in proportion is separated from an aqueous solution and dried.   The resin according to claim 1, wherein the colloidal solution of inorganic fine particles is a colloidal solution of at least one inorganic fine particle selected from silicon oxide, titanium oxide, aluminum oxide, a composite oxide in which zinc oxide and antimony pentoxide are combined. A method for producing a composite composition.   The resin composite composition according to claim 1 or 2, wherein the colloidal solution of inorganic fine particles is a colloidal solution of inorganic fine particles containing 0.1 to 80% by weight of inorganic fine particles with respect to the weight of the solid component in the resin emulsion. Manufacturing method. Claim ratio of the average primary particle size in the resin emulsion and (D _A) and the average particle size of the inorganic fine colloidal solution of the inorganic fine particles _{(D B) (D B /} D A) is 0.1 or more 1 The manufacturing method of the resin composite composition in any one of -3.   The method for producing a resin composite composition according to any one of claims 1 to 4, wherein the resin emulsion is a resin emulsion obtained by emulsion polymerization.   The resin composite composition obtained by the manufacturing method of the resin composite composition in any one of Claims 1-5. A resin composite composition obtained by the method for producing a resin composite composition according to claim 6, wherein the melting point of the resin in the parallel plate mode of the dynamic viscoelasticity measuring device (when the resin is an amorphous resin) The ratio (V _0.1 / V ₁ ) of the viscosity (V ₁ ) at ₁ rad / sec and the viscosity (V _0.1 ) at _0.1 rad / sec, measured at a temperature equal to or higher than the glass transition point, is 1.4 or higher. A resin composite composition.   The resin composite composition according to claim 6 or 7, wherein a storage elastic modulus at 200 ° C of the resin composite composition is 1.7 times or more that of a single resin.   The granulated powder obtained by granulating the resin composite composition in any one of Claims 6-8.   The pellet obtained by melt-extruding the resin composite composition or granulated powder in any one of Claims 6-9.   The molded product obtained from the resin composite composition in any one of Claims 6-10, granulated powder, or a pellet.   The molded article according to claim 11, which is obtained by compression molding, extrusion molding, transfer molding, blow molding, injection molding, rotational molding or lining molding.   The molded article according to claim 11 or 12, wherein the molded article is selected from tubes, sheets, rods, fibers, packings, linings, wire coatings and seal rings.

Images