JP2611888B2 - Method for producing polymer composite in which fine particles are dispersed - 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 fine particles are dispersed, and more particularly, to a method for heating a crystalline polymer at a temperature 150 to 550.degree. The present invention relates to a method for producing a polymer, in which a film is prepared by rapidly cooling the film, and a metal adhered to the surface of the film or a metal mixed in the film is finely divided and dispersed in a polymer.

[0002]

2. Description of the Related Art At present, various functional polymers having conductivity have been developed. Among them, P-acetylene, P-paraphenylene, P-paraphenylenevinylene, P-thiophene, and P-allinine , There is a group of polymers utilizing π-conjugated electrons represented by P-pyrrole and the like,
It is known that the conductivity is approximately 1 to 10 ⁵ S / cm, which is almost equivalent to that of a metal. On the other hand, as another polymer material having conductivity, there is a polymer matrix in which a conductor such as metal powder, metal fiber, or carbon black is filled, and the conductivity is 10 ^{−4 to 1} S / cm. It is low.

[0003] By the way, since most of the metal fine particles are used for forming the surface and the proportion of the atoms exposed on the surface is large, the physical and chemical activities are large, and the properties are significantly different from those of the bulk metal. It has been known. Considering the large surface area, it has been tried for applications such as catalysts, heat exchange materials, unique conductive materials, magnetic materials, photoelectric conversion materials, biomaterials, and drugs.

[0004]

However, if a conjugated bond is formed in the conductive polymer, it is extremely difficult to mold into a thin film, film, wire, or the like because it is not soluble in a solvent and molding is extremely difficult. In addition, there is a big problem that the conductivity is lowered when left in air for a long time. On the other hand, in the polymer composite material, since the conductivity is ensured in a state where the conductors are in contact with each other, there is a disadvantage that the contact state of the conductors varies greatly in the matrix and a resistance distribution occurs.

On the other hand, metal fine particles are liable to be ignited or exploded in the air or extremely oxidized due to their high activity, and the fine particles are re-sintered and aggregated to change the particle size. Difficult to handle and physical,
Due to the problem of changing chemical properties, the results have been extremely limited industrially.

The present inventors have paid attention to such a problem, and have set the crystalline polymer at 150 to 550 ° C. below its melting temperature.
If a low-viscosity liquid material that does not work with intermolecular interaction obtained by heating at a high temperature is super-quenched, the metal that is in close contact with the surface of a film or the like that is a super-quenched material or a metal that is previously mixed in this film However, the inventors have found a peculiar phenomenon in which the film is finely divided as the film is thermally stabilized and uniformly dispersed in a polymer, and the present invention has been achieved.

[0007]

That is, in the method for producing a polymer composite in which fine particles are dispersed according to the present invention, a crystalline polymer is heated at a temperature 150 to 550 ° C. higher than its melting temperature to reduce the viscosity. And then supercooled at a cooling rate of 100 ° C./sec or more to produce a thermodynamically unstable polymer layer. To stabilize the polymer layer by heating the metal layer to form fine particles of metal in the metal layer and disperse the metal in the polymer layer.

In another method, a crystalline polymer and a metal powder are mixed, and the mixture is heated at a temperature 150 to 550 ° C. higher than the melting temperature of the crystalline polymer to obtain a low-viscosity liquid. Is rapidly quenched at a cooling rate of 100 ° C./sec or more to produce a thermodynamically unstable polymer layer, which is heated below the melting temperature to stabilize the polymer layer, thereby reducing the metal powder. There is a method of dispersing the fine particles.

That is, in the process of the present invention, as shown in FIG. 1 to FIG. 4, first, as a first process, a raw material composed of a crystalline polymer 1 is put into a container 2 and this is decomposed into a polymer decomposition product. Alternatively, the vaporized material is put into a heating furnace 3 having a duct function capable of exhausting and recovering the gas, and the temperature of the heating furnace 3 is set to 150 to 550 ° C., more preferably 200 to 550 ° C., from the melting temperature of the polymer.
Maintain 350 ° C. higher temperature. The crystalline polymer 1 is left in the heating furnace 3 for a predetermined time until a low-viscosity liquid 4 is formed without intermolecular interaction.

FIG. 5 is a schematic diagram showing the relationship between the heating temperature and the viscosity, decomposition and vaporization amount of a crystalline polymer. In general, as the heating temperature increases, the melting point of the crystalline polymer in a solid state increases to the melting point. If it exceeds, it becomes liquid and becomes a high-viscosity liquid region due to the intermolecular interaction of the polymer, and if it exceeds this region, the viscosity starts to decrease rapidly. This temperature is defined as Te. Further, when the temperature rises above Te, the decomposition of the polymer,
The amount of vaporization begins to soar. This temperature is defined as Th. Further, when the temperature is increased, the decomposition of the polymer becomes extremely severe.
Therefore, the heating temperature of the crystalline polymer in the method of the present invention is in the range of Te to Th described above, and this temperature range varies depending on the type of the polymer.

The crystalline polymer used in the present invention is, for example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 69, high-density polyethylene (HDP
E), low-density polyethylene (LDPE), polyethylene terephthalate (PET), polyvinyl alcohol, polyphenylene sulfide (PPS) and the like. When these polymers are used, Te is about 150 ° C. higher than the melting point, and Th is 550 ° C. higher than the melting point. More preferably, the temperature range of Te to Th is 200 to 350C from the melting point.
High temperature .

It takes at least 30 seconds for the temperature of the crystalline polymer to rise uniformly at the above temperature. If it is placed too long, the polymer will be severely decomposed and the yield will be poor, so the retention time of the present invention is 30 seconds to 30 minutes.

Next, as shown in FIG. 2, as a second step, a low-viscosity liquid 4 of a crystalline polymer is poured into a mold 5 maintained at about 20 ° C., and is rapidly quenched at a cooling rate of 100 ° C./sec or more. Then, a polymer layer 6 made of a mold such as a film having a thickness of about 300 μm is prepared. The mold 5 usually needs to be at least 150 ° C. lower than the melting point of the crystalline polymer,
Therefore, the mold 5 is cooled with water or with liquid nitrogen. In order to continuously produce the super-cooled polymer layer 6, it is preferable that the cooling water is refluxed and constantly cooled. When the cooling rate is 100
When the temperature is lower than ° C / sec, the polymer layer 6 having a thermodynamically unstable structure for dispersing the fine particles 9 cannot be obtained.

Subsequently, the ultra-quenched polymer layer 6, which is thermodynamically unstable, is placed on a glass substrate 8, and the third
As shown in the figure, the process is shifted to a step of bringing the metal layer 7 into close contact with the surface. In this step, the metal layer 7 is deposited on the polymer layer 6 by a method such as vapor deposition of the metal 7 on the polymer layer 6 by a vacuum deposition apparatus, or by directly attaching a metal foil or a metal plate to the polymer layer 6. The metal material is gold,
Silver, platinum, copper, iron, nickel, cobalt, tin, zinc,
Cerium, yttrium and the like are not particularly limited.

The composite in which the metal layer 7 and the polymer layer 6 thus obtained are in close contact with each other is heated to shift the polymer layer 6 to a stable state. In this step, the polymer layer 6 with the metal layer is heated in a thermostat at a temperature lower than the melting temperature of the crystalline polymer. As a result, as shown in FIG.
Has a particle size of 1,000 nm or less, preferably 300 nm or less.
The fine particles 9 of metal or metal oxide having a diameter of 10 nm or less, more preferably 100 nm or less, diffuse and penetrate into the polymer layer 6, and this state continues until the polymer layer 6 is completely relaxed. The attached metal layer 7 also has a reduced thickness and eventually disappears. (See FIGS. 3 and 4.) Therefore, all the metal layers 7 are fine particles 9 of metal or metal oxide.
In order to disperse the polymer layer 6 in the polymer layer 6, it is necessary to adjust its thickness.

The fine particles 9 contain a metal such as gold, silver and platinum, and a metal oxide such as Cu ₂ O, Fe ₃ O ₄ , ZnO and Y ₂ O ₃ .

When the polymer layer 6 is heated in this step,
It can be seen that the polymer layer 6 shows a unique coloring due to the interaction with the metal or metal oxide fine particles 9, and that the metal or metal oxide fine particles 9 permeate into the polymer layer 6.
Also, this color can vary depending on the type of metal or metal oxide, the particle size of the metal or metal oxide, and the type of polymer. The polymer composite 10 thus obtained is
As shown in FIG. 4, the fine particles are separated and dispersed independently.

Further, as another manufacturing method of the present invention,
The crystalline polymer and metal powder having a particle diameter of 1 to 30 μm are mixed, and a container containing the mixture is put into the heating furnace 3 having the above-described duct function, and the heating furnace 3 is set in a range of Te to Th. Set for a predetermined time to make a low-viscosity liquid, which is about 20 ° C
Into the mold 5 and ultra-rapidly cooled at a cooling rate of 100 ° C./sec or more to produce the polymer layer 6. This polymer layer 6
Is heated and relaxed below the melting temperature of the crystalline polymer, and the metal powder is separated and dispersed as fine particles having a particle diameter smaller than the original particle diameter. The size of the fine particles is 1,000
nm or less, specifically 300 mm or less, or 100
nm or less.

The thus obtained polymer composite 10
It has a very high catalytic activity of fine particles of metal, such as conductive polymers and conductive paste. Appropriate selection of a magnetic memory expected to have a memory capacity, a light or heat responsive material utilizing the fact that the structure and distance between a polymer and the fine particles are changed by stimulation of light or heat, and a type of polymer and metal Optical materials such as liquid crystal color display, sintering accelerators and bonding materials that utilize the fact that the sintering temperature of powdered metal is reduced by fine particles because they are transparent and exhibit a unique color, and the specific heat capacity of the fine particles is large. Polymers that utilize
It is applied to heat exchange membranes made of metal or metal oxide fine particle composites, large capacity capacitor materials, various gas sensors, and the like.

[0020]

Next, the present invention will be described in more detail with reference to specific examples. Example 1 A polymer pellet of nylon 11 (5 g) was charged into a container,
This was left in a heating furnace with a duct set at a predetermined temperature for a predetermined time to convert the crystalline polymer into a low-viscosity liquid.
All of this liquid was refluxed with cooling water, poured into a flat mold maintained at a predetermined temperature, and rapidly cooled to a thickness of 200 to
A 300 μm film was produced. The residual polymer amount (%) was determined by dividing the total amount of the weight of the film and the weight attached to the container at this time by the amount of the polymer pellets previously charged in the container.

Next, the film is peeled off from the mold, placed on a glass substrate, placed in a vacuum evaporation apparatus, and a copper wire or a gold wire is wound around a tungsten wire and melted by heating to 10 ⁻⁴ to 10 ⁻⁴ . Vapor deposition was performed under a vacuum of 10 ^-6 Torr, a copper or gold vapor-deposited film was deposited on the film, and the glass plate was taken out of the vacuum vapor deposition apparatus. This was left in a thermostat set at 120 ° C. for 30 minutes to obtain a polymer composite. The color of the surface of the polymer composite thus obtained and the size of the dispersed fine particles were determined based on a photograph of the composite taken with a transmission electron microscope. This is shown in Table 1.

[0022]

[Table 1]

Further, the samples of Examples 1-4 and 1-8 obtained by adhering a copper vapor-deposited film on the surface of the film, and the sample after heating them were thin-film X-rays having an incident angle of 1.0 °. The X-ray diffraction pattern was measured using a diffractometer (RINT1200 manufactured by Rigaku Corporation). The results are shown in FIGS.

In this X-ray diffraction pattern, the solid line is a laminate of the film and the metal film, and the dotted line shows the composite after the laminate was left in a thermostat at 120 ° C. for 30 minutes and heat-treated. According to this, in the patterns before each heat treatment, diffraction peaks of the respective metals and nylon 11 appeared in each case, indicating a configuration in which a metal vapor-deposited film was laminated on the nylon 11 polymer layer. Further, it can be seen that the pattern after each heat treatment changes the structure of nylon 11 and is relaxed by the heat treatment. Also, the fact that the diffraction peak width (half width) of each metal is large indicates that each metal is finely divided and dispersed in nylon 11. When using copper,
Copper changes to Cu ₂ O (copper oxide), and it can be seen that these fine particles are dispersed in nylon 11.

Comparative Example 1 As shown in Table 2, the heating conditions for the polymer pellets were different from those in Example 1, and the other methods were the same as in Example 1 to obtain samples. Table 2 shows the color of the film before and after the heat treatment, the size of the fine particles, and the like.

[0026]

[Table 2]

According to this, in Comparative Example 1-1, since the heating temperature of the furnace was too high, decomposition of the crystalline polymer during heating,
Poor yield due to large amount of vaporization and large metamorphosis
Cannot produce a film with a uniform thickness
Was.

In Comparative Example 1-2 , since the cooling rate is low and the low-viscosity liquid is gradually cooled, the polymer layer does not have an unstable structure, and fine particles are dispersed in the film. Was impossible. Further, Comparative Examples 1-3 and 1-
In No. 4 , since the heating temperature was low, the crystalline polymer became a high-viscosity liquid, and it was impossible to obtain a polymer composite even if it was rapidly quenched to form a film. FIG. 8 shows Comparative Example 1.
-3 shows an X-ray diffraction pattern of the sample before and after the heat treatment.
Since the diffraction patterns of the sample before and after the heat treatment are the same, it can be seen that the metal is finely divided and is not dispersed in the film.

Example 2 and Comparative Example 2 Polymer composites were obtained in the same manner as in Example 1 by using pellets of various crystalline polymers. Table 3 shows the production conditions, the color of the film before and after the heat treatment, the size of the fine particles, and the like.

[0030]

[Table 3]

According to this, it can be seen that a desired polymer composite cannot be obtained from an amorphous polymer such as polycarbonate or polymethyl methacrylate, or a degradable polymer such as polyimide.

Example 3 and Comparative Example 3 A polymer powder and a copper powder (particle diameter: about 10 μm) were previously mixed,
The mixture was placed in a container, and heated in a heating furnace with a duct at a heating temperature and a holding time shown in Table 4 to obtain a low-viscosity liquid. A sample was obtained by heat treatment in a bath. Table 4 shows the color of the film and the size of the fine particles before and after the heat treatment of these samples.
Shown in

[0033]

[Table 4]

According to this, a low-viscosity liquid of a mixture in which a metal powder is dispersed in a crystalline polymer in advance is rapidly quenched to form a film, and even when the film is heated, the metal powder is atomized. You can do it.

[0035]

As described above, in the method for producing a polymer composite in which fine particles are dispersed according to the present invention, the crystalline polymer is heated at a temperature about 150 to 550 ° C. higher than its melting temperature to obtain a low-viscosity liquid. This is rapidly cooled at a cooling rate of 100 ° C./sec or more to produce a thermodynamically unstable polymer layer, and a metal layer is adhered to the surface of the polymer layer, and then heated at a temperature lower than the melting temperature. By stabilizing the polymer layer by doing so, the metal of the metal layer can be finely divided and uniformly dispersed in the polymer layer.

In the method of the present invention, the crystalline polymer and the metal powder are mixed, and the mixture is heated at a temperature about 150 to 550 ° C. higher than the melting temperature of the crystalline polymer to form a low-viscosity liquid. Is rapidly quenched at a cooling rate of 100 ° C./sec to produce a thermodynamically unstable polymer layer, which is heated and relaxed to separate and disperse the underlying metal powder as fine particles having a smaller particle size. Therefore, the polymer composite can be produced safely without danger of ignition or explosion of the fine particles.

[Brief description of the drawings]

FIG. 1 shows a step of heating a crystalline polymer placed in a container to a viscous liquid.

FIG. 2 shows a step of pouring a viscous liquid into a mold to obtain a super-quenched polymer layer.

FIG. 3 is a cross-sectional view showing a state after heating a laminate in which a metal layer is laminated on the surface of a polymer layer.

FIG. 4 is a cross-sectional view of a polymer composite obtained by the method of the present invention.

FIG. 5 is a schematic view showing the relationship between the heating temperature of a crystalline polymer and the viscosity, decomposition and vaporization amounts.

FIG. 6 is a thin-film X-ray diffraction pattern diagram of a laminate of a polymer layer and a metal film obtained according to Example 1-4 before and after heat treatment.

FIG. 7 is a thin-film X-ray diffraction pattern diagram before and after heat treatment of a laminate of a polymer layer and a metal film obtained in Example 1-8.

FIG. 8 is a thin-film X-ray diffraction pattern diagram of a laminate of a polymer layer and a metal film obtained in Comparative Example 1-3 before and after heat treatment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crystalline polymer 2 Container 3 Heating furnace 4 Low-viscosity liquid 5 Die 6 Polymer layer 7 Metal layer 9 Fine particles 10 Polymer composite

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein the melting point of the crystalline polymer is 150
A liquid having a low viscosity is heated at a high temperature of ５550 ° C., and then rapidly cooled at a cooling rate of 100 ° C./sec or more to produce a thermodynamically unstable polymer layer. After the metal layer is brought into close contact with the metal layer, the metal layer is heated to a temperature lower than the melting temperature to stabilize the polymer layer, whereby the metal of the metal layer is made finer and dispersed in the polymer. A method for producing a molecular composite. 2. A crystalline polymer and a metal powder are mixed, and the mixture is heated to a melting point of the crystalline polymer of 150 to 550.
C. to a low viscosity liquid by heating at a high temperature.
Ultra-rapid cooling at a cooling rate of at least ℃ / sec to produce a thermodynamically unstable polymer layer, which is heated below the melting temperature to form fine metal particles to be dispersed. A method for producing a polymer composite in which is dispersed.