JP2554599B2 - Method for producing polymer composite having high concentration of fine particles dispersed therein - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polymer composite in which high concentration fine particles are dispersed, and more specifically, high concentration fine particles dispersed by increasing the concentration of fine particles made of metal or metal oxide are dispersed. The present invention relates to a method for producing a polymer composite.

[0002]

2. Description of the Related Art Conventional methods for producing a fine particle-dispersed composite include co-deposition method in a gas phase, co-sputtering method, co-precipitation method in a liquid phase, and solid phase. There is a precipitation method, an ion implantation method or the like. In any of these methods, the metal fine particles are made of an organic or inorganic substance for the purpose of aggregating the metal in the atomic or ionic state to form fine particles, and further improving the handling property without causing grain growth. It was coated with a matrix to make a composite. Recently, a thermodynamically unstable metastable polymer layer was prepared, a metal layer was adhered to the surface of the polymer layer, and the polymer was heated to metastable polymer. JP-A-3-273060 also discloses a method in which a metal or metal oxide of a metal layer is made into fine particles by stabilizing the layer and dispersed in a polymer.

[0003]

However, a problem common to the co-evaporation method, the co-sputtering method, the co-precipitation method, the precipitation method, and the ion implantation method is that the metal fine particles are very likely to aggregate. Therefore, it becomes difficult to increase the concentration of the metal fine particles in the composite, and further, the productivity is extremely deteriorated. Further, the low concentration of the metallic particles indicates that the contribution of the fine metal particles to the physical properties of the composite is small, which makes the use of the composite extremely narrow. Also, in the method disclosed in Japanese Patent Laid-Open No. 3-273060, the metal cannot be made into fine particles anymore due to the relaxation of the polymer by the radiant heat at the time of metal deposition, or the metal becomes fine particles during the heat treatment. Prior to this, relaxation of the polymer might be completed and the sample temperature had to be tightly controlled. The present inventors focused on such problems, and an object thereof is to provide a method for producing a polymer composite in which high-concentration fine particles in which the concentration of fine particles made of a metal or a metal oxide is increased is dispersed. To do.

[0004]

That is, in the method for producing a polymer composite in which high-concentration fine particles are dispersed according to the present invention, a thermodynamically unstable metastable polymer layer is prepared, After adhering a metal layer to the surface of the polymer layer, the polymer is heated to stabilize the polymer layer in a metastable state, so that the metal of the metal layer is made into fine particles and dispersed in the polymer. A feature is characterized in that a precipitate is prepared by centrifuging a fine particle dispersion solution obtained by dissolving the polymer composite in an organic solvent, and the organic solvent is removed from the obtained precipitate.

In the fine particle dispersion solution of the production method of the present invention,
Since the fine particles of metal or metal oxide strongly interact with the polymer, they are very stably dispersed in a solution state or below the melting point of the polymer. Therefore, in the precipitate obtained by centrifuging the fine particle dispersion solution, there is no aggregation of fine particles of metal or metal oxide,
A polymer composite having an increased concentration of fine particles can be obtained.

That is, the steps of the method of the present invention will be described in detail below. First, in the case of obtaining a polymer composite,
Another is to form the polymer layer into a thermodynamically unstable state. Specifically, this is a vacuum evaporation method in which a polymer is heated in a vacuum to melt and evaporate to solidify a polymer layer on a substrate, or the polymer is melted at a melting temperature or higher and is left in this state. There is a melting and quenching solidification method in which the polymer layer is immediately attached to liquid nitrogen or the like to be rapidly cooled and a polymer layer is attached onto the substrate.

In the case of the vacuum vapor deposition method, a vacuum degree of 10 ⁻⁴ to 10 ⁻⁶ Torr is used and a vapor deposition rate is 0.1 to 100 μm / min, preferably 0.5 to 5 μm, using an ordinary vacuum vapor deposition apparatus.
At m / min, a polymer layer can be obtained on a substrate such as glass. In the melt-quenching and solidification method, a polymer is melted and cooled at a rate equal to or higher than a critical cooling rate specific to the polymer to obtain a polymer layer. The obtained polymer layer is placed in a thermodynamically unstable metastable state, and shifts to an equilibrium state with the passage of time.

The polymer used in the present invention is, for example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 69, polyethylene terephthalate (PET),
Polyvinyl alcohol, polyphenylene sulfide (P
PS), polystyrene (PS), polycarbonate, polymethylmethacrylate, etc., and those having a molecular cohesive energy of 2000 cal / mol or more are preferable. This polymer includes a crystalline polymer and an amorphous polymer which are usually called. Regarding the molecular cohesive energy, the Chemical Handbook, edited by the Chemical Society of Japan (edited in 1974)
890, page 890.

Subsequently, the thermodynamically unstable metastable polymer layer is transferred to the step of bringing the metal layer into close contact with the surface thereof. In this step, a metal layer is deposited on the polymer layer by a method such as depositing a metal on the polymer layer using a vacuum vapor deposition apparatus, or directly adhering a metal foil or a metal plate to the polymer layer. The metals include Au, Ag, Cu,
Ti, V, Cr, Mn, Fe, Ni, Zn, Cd, Y,
There are W, Sn, Ge, In and Ga, and there is no particular limitation.

The composite in which the metal layer and the polymer layer are in close contact with each other is heated at a temperature not lower than the glass transition point and not higher than the melting point of the polymer to bring the polymer layer into a stable state. As a result, the metal of the metal layer is 100 nm or less and has a maximum particle size distribution in the region of 1 to 10 nm, or Cu ₂ O, Fe ₃
Fine particles of metal oxides such as O ₄ , ZnO and Y ₂ O ₃ are diffused and permeated into the polymer layer, and this state continues until the polymer layer is completely relaxed and adheres to the polymer layer. The metal layer also decreases in its thickness and eventually disappears. The fine particles are distributed in the polymer layer without being aggregated.

In the present invention, the method for producing the polymer composite is not limited to the above-mentioned method, and, for example, a vapor phase method belonging to the melt vaporization method, a liquid phase method belonging to the precipitation method, a solid phase method or a dispersion method is used. There is a method of producing ultrafine particles and mechanically mixing the ultrafine particles with a polymer composed of a solution or a melt, or a method of simultaneously evaporating the polymer and metal and mixing them in a gas phase.

The obtained polymer composite is mixed and dissolved in a solvent consisting of an organic solvent such as metacresol, dimethylformamide, dichloroethane, chloropropanol and the like to obtain a fine particle dispersion solution in which fine particles are dispersed. Since the particles have a small particle size and have an interaction with the polymer, separation, precipitation and aggregation of the particles do not occur in the solution. In this case, the content of fine particles is 0.01 to 60.
% By weight.

The fine particle dispersion solution is separated into a precipitate and a supernatant by a centrifuge, and the supernatant is removed to remove the precipitate. The precipitate is paste-like and contains fine particles of metal or metal oxide dispersed without agglomeration.
The precipitate is applied on a substrate such as glass and dried to remove the organic solvent to obtain a target polymer composite in which high-concentration fine particles of at least 70% by weight are dispersed. it can.

[0014]

Next, the present invention will be described in more detail with reference to specific examples. Example 1 Using a vacuum evaporation apparatus, 5 g of nylon 11 polymer pellets were put into a tungsten board, and 10 ^-6 Torr
Depressurize to. Then, a voltage is applied to heat the tungsten board in vacuum to melt the polymer, and 10 ^-4 to 10 ^-6 T is formed on the substrate (glass plate) placed on the evaporation source.
A polymer layer of a vapor-deposited film having a thickness of about 5 μm was obtained at a rate of vacuum of orr at a rate of about 1 μm / min. The molecular weight of this polymer layer is about 1/2 to 1/10 of that of the polymer pellet. Further, a metal chip of gold or copper was put in a tungsten board, heated and melted, and vapor deposition was performed at a vacuum degree of 10 ⁻⁴ to 10 ⁻⁶ Torr to deposit a copper vapor deposition film on the polymer layer. This was taken out from the vacuum vapor deposition apparatus and left in a constant temperature bath kept at 120 ° C. for 10 minutes to obtain a composite.

The obtained composite was dissolved in meta-cresol and well stirred to form a fine particle dispersion solution, which was placed in a centrifuge and centrifuged at 15,000 rpm for 1 hour. The precipitate after centrifugation and the supernatant were applied on glass and then dried at 120 ° C. for 30 minutes to remove metacresol to prepare a film-shaped composite. The metal content of the composite was determined by the ash measurement method, and the particle size was determined by calculating the full width at half maximum by the X-ray diffraction method and calculating the crystal size from the Scherrer equation. The color tone of the composite was visually observed. Table 1 shows the results.

[0016]

[Table 1]

As a result, it was revealed by centrifugation that the obtained composite had a high concentration of fine particles, and the permeation color of the precipitate showed a predetermined color due to the plasmon resonance absorption of the fine particles, like the supernatant. However, the reflected light has unique optical characteristics.

Further, an electrode was placed with gold in the thickness direction of the film-shaped composite, and the time change of the current value when a constant voltage was applied was measured. The results are shown in FIGS. In the conventional case where the gold fine particle concentration is as low as 27% by weight, the electrical behavior of the matrix nylon is strongly shown, but in the case of the present embodiment where the gold fine particle concentration is as high as 79% by weight, the current value increases with the increase of the applied voltage. However, it can be seen that the composite shows unique properties.

[0019]

INDUSTRIAL APPLICABILITY As described above, in the method for producing a polymer composite in which high-concentration fine particles are dispersed according to the present invention, the fine particles of metal or metal oxide in the fine particle dispersion solution strongly interact with the polymer. Therefore, even if a precipitate is prepared by centrifuging this fine particle dispersed solution, a polymer composite having specific characteristics with increased concentration of fine particles can be obtained without aggregation of fine particles.

[Brief description of drawings]

FIG. 1 is a diagram showing a change in current value when 1 V is applied to a conventional polymer composite having a gold fine particle concentration of 27% by weight.

FIG. 2 is a diagram showing a change in current value when 10 V is applied to the polymer composite used in FIG.

FIG. 3 is a diagram showing a change in current value when 100 V is applied to the polymer composite used in FIG.

FIG. 4 is a diagram showing a change in current value when 10 mV was applied to the polymer composite of this example having a high gold particle concentration of 79% by weight.

5 is a diagram showing a change in current value when 50 mV is applied to the polymer composite used in FIG.

FIG. 6 is a diagram showing a change in current value when 200 mV is applied to the polymer composite used in FIG.

Claims (1)

(57) [Claims] 1. A polymer layer in a metastable state which is thermodynamically unstable is produced, and a metal layer is adhered to the surface of the polymer layer, and then the polymer is heated to produce a polymer in a metastable state. By stabilizing the layer, the metal of the metal layer is made into fine particles and dispersed in a polymer, and a precipitate is prepared by centrifuging a fine particle dispersion solution obtained by dissolving the polymer composite in an organic solvent. A method for producing a polymer composite in which high-concentration fine particles are dispersed, which comprises removing an organic solvent from the obtained precipitate.