JP2010265387A - Method for producing carbon nano composite resin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method by which a satisfactory carbon nano composite resin material can be stably and more easily obtained. <P>SOLUTION: ST01: A resin material (A), a carbon nano material (B) and a higher fatty acid metal soap (C) are prepared in prescribed amounts. ST02: The resin material and the carbon nano material are put in a mixer and mixed while a temperature for softening the whole surface of the resin material is maintained. Thereby, a mixture 10 can be obtained. ST03: The obtained mixture 10 is kneaded by using a kneader to obtain the carbon nano composite resin material 15 having e.g. a pellet shape. The higher fatty acid metal soap (C) known as a fluidization promotor of a resin is used as a dispersant. Flocculation of the carbon nano material can be suppressed by using the higher fatty acid metal soap (C) as the dispersant and thus mechanical properties can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for producing a carbon nanocomposite resin material as a material used for resin molding.

  A carbon nanofiber, which is a representative example of the carbon nanomaterial, has a form in which a sheet of carbon atoms arranged in a hexagonal network is wound in a cylindrical shape, and has a diameter of 1.0 nm (nanometer) to 150 nm. Because it is a level, it is called a carbon nanofiber (or carbon nanotube). The aspect ratio is 100 or more.

Such carbon nanomaterials have been added to resin materials to improve the mechanical properties and electrical properties of resin products.
However, since the carbon nanomaterial is much finer than the carbon material of μm size, it is easy to aggregate and difficult to handle. Therefore, conventionally, it has been proposed to attach a carbon nanomaterial to the surface of resin particles by mechanical stirring called a mechanical alloy method (see, for example, Patent Document 1 (FIGS. 1 and 2)).

The technique of patent document 1 is demonstrated based on drawing.
FIG. 8 is a conventional manufacturing flow diagram, where STxx indicates a step number.
ST101: First, a predetermined amount of resin material and carbon nanomaterial are prepared. The resin material is preferably a material having a large surface area such as powder or granular material.
ST102: The resin material and the carbon nanomaterial are put into a mixer and mixed while maintaining a temperature at which the entire surface of the resin material is softened. Thus, a mixture can be obtained.

  If the resin material is polypropylene, the temperature at which the entire surface of the resin material softens is 160 to 170 ° C., and the heating temperature is 140 to 160 ° C. Further, if the resin material is PET (polyethylene terephthalate), the melting point temperature is 253 to 265 ° C, and the heating temperature is 200 to 210 ° C.

  FIG. 9 is a schematic view of a mixture obtained by a conventional method. In the mixture 110, an infinite number of carbon nanomaterials 112 are attached to the surface of the resin material 111. If it is this form, it will be avoided that the carbon nanomaterial 112 contacts and aggregates.

When the obtained mixture 110 was put into an injection molding machine, injection molding was performed, and the tensile strength of the obtained molded product was measured, the following results were obtained.
FIG. 10 is a graph showing the relationship between the mixing time and the tensile strength. From the start of mixing (stirring) to 5 hours, the tensile strength increased with increasing mixing time. However, the tensile strength decreased after that. It is assumed that due to the increased mixing time, the carbon nanomaterial was cut and the fiber length was lost. It is conceivable that the optimum mixing time varies depending on the type of the resin material, the addition ratio of the carbon nanomaterial, etc., and skill is required to match the optimum value. That is, the technique of Patent Document 1 requires an advanced work form.

  In consideration of productivity, a production method that can stably obtain a good product mixture (carbon nanocomposite resin material) by a simpler method is required.

JP 2005-298553 A

  An object of the present invention is to provide a production method capable of stably obtaining a good carbon nanocomposite resin material by a simpler method.

The invention according to claim 1 is a method for producing a carbon nanocomposite resin material as a material used for resin molding,
Preparing a resin material (A) having an aryl group and a carbonyl group, a carbon nanomaterial (B), and a higher fatty acid metal soap (C) mainly composed of a transition metal salt;
A mixing step of mixing the resin material (A) with the carbon nanomaterial (B) and the higher fatty acid metal soap (C) to obtain a mixture;
The obtained mixture is kneaded with a kneader to obtain a carbon nanocomposite resin material, and is characterized by comprising a molding step.

  The invention according to claim 2 is characterized in that the resin material (A) is composed of one or more of a polycarbonate resin, a polyester resin, an acrylic resin, and an aromatic polyether ketone resin.

  The invention according to claim 3 is characterized in that the resin material (A) is a powder.

  The invention according to claim 4 is characterized in that in the mixing step, heating is performed so that the carbon nanomaterial (B) adheres to the surface of the resin material (A).

  The invention according to claim 5 is characterized in that the higher fatty acid metal soap (C) contains zinc.

  The invention according to claim 6 is characterized in that the higher fatty acid metal soap (C) is mixed in an amount equivalent to 100 ppm to 1000 ppm.

  In the invention which concerns on Claim 1, higher fatty acid metal soap (C) was mixed with the resin material (A) and the carbon nanomaterial (B) at the mixing process. By using the higher fatty acid metal soap (C) as a dispersant, aggregation of the carbon nanomaterial can be suppressed and mechanical properties can be improved. That is, the higher fatty acid metal soap (C) known as a resin fluidization accelerator is used as a dispersant in the present invention.

And if it is the conventional mechanical alloy method, stirring for 5 to 10 hours is required, but according to this invention, it can be completed by mixing for about 30 minutes, and the improvement of productivity can be aimed at.
That is, a non-defective carbon nanocomposite resin material can be stably obtained by a simpler method.

  In the invention according to claim 2, the resin material (A) is one or more of a polycarbonate resin, a polyester resin, an acrylic resin, and an aromatic polyether ketone resin. Each of these resins has an aryl group and a carbonyl group, and forms a metal complex with a higher fatty acid metal soap. Since these resins are easily available and inexpensive, they contribute to the cost reduction of the carbon nanocomposite resin material.

  In the invention which concerns on Claim 3, a powdered resin material (A) is employ | adopted. If it is powder, the carbon nanomaterial can be uniformly dispersed on the surface.

  In the invention according to claim 4, in the mixing step, heating is performed so that the carbon nanomaterial (B) adheres to the surface of the resin material (A). The carbon nanomaterial can be fused to the surface of the resin material, and the bondability between the two can be strengthened.

  In the invention according to claim 5, the higher fatty acid metal soap (C) contains zinc. Zinc is easy to obtain and inexpensive.

  In the invention according to claim 6, the higher fatty acid metal soap (C) is mixed in an amount equivalent to 100 ppm to 1000 ppm. If it is less than 100 ppm, the dispersing action is insufficient, aggregation occurs, and the mechanical properties and the like deteriorate. On the other hand, if it exceeds 1000 ppm, the dispersing action is sufficient, but the resin properties are lost and the mechanical properties and the like deteriorate. Therefore, it is desirable that the higher fatty acid metal soap (C) has an equivalent amount of 100 ppm to 1000 ppm.

It is a manufacturing flow figure concerning the present invention. It is a figure which shows the example of the mixing apparatus used for manufacture of this invention. It is a figure which shows the example which applied the mixing apparatus to the injection mechanism. It is a graph which shows the relationship between the addition amount of zinc stearate, and tensile strength. It is a graph which shows the relationship between the addition amount of zinc stearate, and elongation. It is a graph which shows the relationship between the addition amount of a zinc stearate, and a dispersion rate. It is a schematic diagram explaining the dispersion | distribution effect | action of a zinc stearate. It is a conventional manufacturing flowchart. It is a schematic diagram of the mixture obtained by the conventional method. It is a graph which shows the relationship between the mixing time and the tensile strength in the conventional method.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a manufacturing flow diagram according to the present invention, where STxx indicates a step number.
ST01: First, a predetermined amount of resin material (A), carbon nanomaterial (B), and higher fatty acid metal soap (C) are prepared. The resin material (A) is preferably a material having a large surface area such as a powder or a granular material.

  The resin material (A) is not limited as long as it is a resin having an aryl group and a carbonyl group. Such resins include polycarbonate resins, polyester resins, acrylic resins, and aromatic polyether ketone resins. One or more of these can be mixed and used.

  The carbon nanomaterial (B) may be of any type as long as it is a nanosize carbon material. Such materials include carbon nanotubes, carbon nanofibers, and fullerenes.

  The higher fatty acid metal soap (C) is not limited as long as it is a conjugate of a higher fatty acid having 12 or more carbon atoms and a transition metal. Higher fatty acids include stearic acid, olefinic acid, lauric acid, myristic acid, and palmitic acid. Transition metals include manganese, copper, and zinc. Among these, zinc stearate is suitable for use because zinc is inexpensive and readily available.

  ST02: The resin material and the carbon nanomaterial are put into a mixing apparatus (FIG. 2, reference numeral 20) and mixed while maintaining a temperature at which the entire surface of the resin material is softened. Thus, the mixture 10 can be obtained.

  ST03: The obtained mixture 10 is kneaded by a kneader to obtain, for example, a pellet-shaped carbon nanocomposite resin material 15. The kneading machine is preferably a single-screw or twin-screw kneader that rotates one or two screws in a cylinder and compresses the mixture 10 while kneading.

Next, a mixing device 20 suitable for carrying out the manufacturing flow described above will be described.
As shown in FIG. 2, the mixing device 20 includes a hopper-shaped container 24 having a lid 23 provided with an inlet 21 for the resin material 11 and an inlet 22 for the carbon nanomaterial 12 and the higher fatty acid metal soap 13, and the container. A heater 25 affixed to the heater 24, a heat insulating material 26 placed on the heater 25, a temperature sensor 27 provided in the container 24 for measuring the internal temperature of the container 24, and a temperature detected by the temperature sensor 27 is predetermined. The temperature control part 28 which controls the output of the heater 25 so that it may become temperature, and the stirring means 30 which stirs and mixes the material in the container 24 are comprised.

  The stirring means 30 includes a stirring motor 32 attached to the lid 23 so that the motor shaft 31 faces downward, a rotating shaft 34 inserted from below into a bearing ring 33 provided on the lid 23, and provided in the middle of the rotating shaft 34. Boss 35, stirring blade 36 protruding radially from boss 35, lower stirring blade 38 for stirring the bottom of container 24, and shaft extending from container 24 to rotatably support the lower end of rotating shaft 34 And a support bracket 37. Reference numeral 50 denotes a heat insulating structure, which is not an essential element, but is desirably interposed on the rotating shaft 34.

The operation of the mixing apparatus 20 having the above configuration will be described next.
First, the heater 25 is energized and controlled by the temperature control unit 28 to maintain the internal temperature of the container 24 at a temperature at which the entire surface of the resin material is softened.
In this state, the stirring motor 32 is started, and the rotating shaft 34, the stirring blade 36, and the lower stirring blade 38 are continuously rotated at a predetermined speed. The valves 41, 42 and 43 are closed.

The valve 41 is opened and a predetermined amount of the resin material 11 is introduced from the inlet 21. The valve 42 is opened and the predetermined amounts of the carbon nanomaterial 12 and the higher fatty acid metal soap 13 are introduced from the inlet 22. close.
Heating with the heater 25 while stirring with the stirring blade 36 and the lower stirring blade 38 softens the surface of the resin material 11 and increases the adhesiveness. Then, the carbon nanomaterial 12 adheres to the surface of the resin material 11. If necessary, the mixture 10 can be dropped by opening the valve 43.

  In principle, the obtained mixture 10 is kneaded by a kneader to obtain a carbon nanocomposite resin material (FIG. 1, reference numeral 15). If the carbon nanocomposite resin material is a pellet, it can be easily transported and stored. The pellet-like carbon nanocomposite resin material can be supplied to a resin molding machine such as an injection molding machine, a compression molding machine, or an extrusion molding machine when necessary.

However, the obtained mixture 10 may be immediately supplied to the resin molding machine without being retained. This form will be described with reference to the next figure.
FIG. 3 is a diagram showing an example in which the mixing apparatus is applied to an injection mechanism. There are various types of resin injection mechanisms, one of which is a pre-plasticizing (generally referred to as pre-plastic) type injection mechanism.
The pre-plastic injection mechanism 70 includes a pre-plastic portion 73 in which a pre-plastic screw 72 is built in a pre-plastic cylinder 71, and a plunger 75 in the injection cylinder 74, and an injection portion 77 in which the plunger 75 is moved forward and backward by an injection ram 76. The injection machine is capable of injecting the material plasticized in advance by the pre-plastic part 73 in the injection part 77.

  By attaching the mixing apparatus 20 of the present invention to the base of the pre-plastic cylinder 71, the mixture in which the carbon nanomaterial 12 is adhered to the resin material 11 can be supplied directly to the injection mechanism 70. The injection mechanism 70 may be a screw-type injection mechanism in addition to the pre-plastic injection mechanism, and may be of any type as long as it is an injection mechanism used for resin injection molding.

(Experimental example)
Experimental examples according to the present invention will be described below. Note that the present invention is not limited to experimental examples.
○ Materials to prepare:
-Resin material (A): PC (polycarbonate resin) powder-Carbon nanomaterial (B): 3% by mass of resin material (A)
Higher fatty acid metal soap (C): zinc stearate, equivalent to 100ppm, 1000ppm or 3000ppm of the whole

○ Mixed:
The resin material (A), the carbon nanomaterial (B), and the higher fatty acid metal soap (C) are charged into a mixing apparatus and stirred and mixed at 150 ° C. for 30 minutes.

○ Dry:
As part of making the specimen, the mixture was dried for 3 hours.
○ Injection molding:
The test piece was obtained and the kneading step was performed, and kneading was performed by an injection molding machine to obtain a test piece.

○ Evaluation of mechanical properties:
The specimen was subjected to destructive inspection, and the tensile strength and elongation were measured. A result is demonstrated based on drawing.
As shown in FIG. 4, the tensile strength increases in proportion to the increase in the addition rate of zinc stearate between 0 and 100 ppm, has a peak between 100 and 1000 ppm, and between 1000 and 3000 ppm. It decreased with increasing zinc stearate addition rate.
That is, a high tensile strength is obtained at 100 to 1000 ppm.

  As shown in FIG. 5, the elongation (elongation from the beginning of elongation to break) increases in proportion to the increase in the zinc stearate addition rate between 0 and 100 ppm, and between 100 and 3000 ppm. It decreased with increasing zinc stearate addition rate. Large elongation was obtained at 100 to 1000 ppm.

○ Dispersibility:
The test piece was broken, the fracture surface was observed with a metal microscope, and the dispersibility was examined. The results are described in the next figure.
Zinc stearate functions as a dispersant, but as shown in FIG. 6, there was a peak of the dispersion rate in the vicinity of 1000 ppm, and the dispersion rate was rather lowered above that. That is, a high dispersion rate was obtained at 100 to 1000 ppm.

The dispersing action of zinc stearate can be explained as follows.
As shown in FIG. 7A, a schematic diagram is assumed in which carbon nanomaterials 82 and 82 are mixed with polycarbonate 81 and 81, which are resin materials, and a steering acid zinc 83 is interposed therebetween.

The zinc (zinc) of the steering acid zinc 83 basically forms a straight-line (two hands) complex, but forms a planar square (four hands) metal complex with weak bonds. Therefore, the oxygen electron of the carboxyl group of the polycarbonate 81 forms a complex with zinc and becomes a planar square. At this time, the benzene ring of the carbon nanomaterial 82 and the benzene ring of the polycarbonate 81 cause π-π stacking, and the carbon nanomaterial 82 is drawn around the polycarbonate 81 as indicated by an arrow (1).
Also, the carbon nanomaterials 82 are attracted to each other as indicated by an arrow (2) by π-π stacking. The arrow (2) causes the carbon nanomaterial 82 to aggregate.

On the other hand, as shown in (b), a repulsive force acts between the C—C single bond existing around Zn (zinc) and the benzene ring of the carbon nanomaterial 82 as shown by an arrow (3).
This repulsive force is sufficiently larger than the attractive force indicated by the arrows (1) and (2). Therefore, the steering acid zinc 83 serves as a dispersant that effectively suppresses aggregation of the carbon nanomaterial 82.

  The higher fatty acid metal soap typified by zinc stearate is not limited as long as it is a conjugate of a higher fatty acid having 12 or more carbon atoms and a transition metal. Higher fatty acids include stearic acid, olefinic acid, lauric acid, myristic acid, and palmitic acid. Transition metals include manganese, copper, and zinc. Among these, zinc stearate is particularly suitable for use because zinc is inexpensive and readily available.

  The present invention is suitable for a method for producing a carbon nanocomposite resin material as a material used for resin molding.

  DESCRIPTION OF SYMBOLS 10 ... Mixture, 11 ... Resin material, 12, 82 ... Carbon nano material, 13 ... Higher fatty acid metal soap, 15 ... Carbon nano composite resin material, 20 ... Mixing apparatus, 81 ... Polycarbonate, 83 ... Zinc stearate.

Claims (6)

A method for producing a carbon nanocomposite resin material as a material used for resin molding,
Preparing a resin material (A) having an aryl group and a carbonyl group, a carbon nanomaterial (B), and a higher fatty acid metal soap (C) mainly composed of a transition metal salt;
A mixing step of mixing the resin material (A) with the carbon nanomaterial (B) and the higher fatty acid metal soap (C) to obtain a mixture;
A method for producing a carbon nanocomposite resin material, comprising: a molding step of kneading the obtained mixture with a kneader to obtain a carbon nanocomposite resin material.   2. The method for producing a carbon nanocomposite resin material according to claim 1, wherein the resin material (A) comprises one or more of a polycarbonate resin, a polyester resin, an acrylic resin, and an aromatic polyetherketone resin.   The said resin material (A) is a powder, The manufacturing method of the carbon nano composite resin material of Claim 1 or Claim 2 characterized by the above-mentioned.   The method for producing a carbon nanocomposite resin material according to claim 3, wherein in the mixing step, heating is performed so that the carbon nanomaterial (B) adheres to the surface of the resin material (A).   The said higher fatty acid metal soap (C) contains zinc, The manufacturing method of the carbon nano composite resin material of any one of Claims 1-4 characterized by the above-mentioned.   The method for producing a carbon nanocomposite resin material according to any one of claims 1 to 5, wherein the higher fatty acid metal soap (C) is mixed in an amount equivalent to 100 ppm to 1000 ppm.

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