WO2017033838A1

WO2017033838A1 - Carbon nanotube aggregate, production method for same, and thermoplastic resin composition containing same

Info

Publication number: WO2017033838A1
Application number: PCT/JP2016/074165
Authority: WO
Inventors: 剛士扇
Original assignee: ハリマ化成株式会社
Priority date: 2015-08-21
Filing date: 2016-08-19
Publication date: 2017-03-02
Also published as: JP2018158957A; TW201708424A

Abstract

Provided are: a carbon nanotube aggregate with which scatter can be reduced, and which has excellent dispersibility in thermoplastic resin and filling properties; and a resin composition that contains the same. A carbon nanotube aggregate that contains carbon nanotubes and a water-soluble rosin-based resin is disclosed in the present description. The water-soluble rosin is preferably one that exhibits neutrality when dissolved in water.

Description

Carbon nanotube aggregate, process for producing the same, and thermoplastic resin composition containing the same

The present invention relates to a carbon nanotube aggregate containing carbon nanotubes and a water-soluble rosin resin, and a thermoplastic resin composition containing the same.

Carbon nanotubes can be composited with a thermoplastic resin to produce a high performance composite material. However, since carbon nanotubes have a low bulk density and a large amount of air is contained per unit volume, there is a problem that uniform mixing with pellets and powders of thermoplastic resin is difficult. For example, when extruding carbon nanotubes and thermoplastic resin, the carbon nanotubes and thermoplastic resin may be separated into layers, so it is necessary to contact the carbon nanotubes with the thermoplastic resin at a higher pressure than usual. Thus, there are problems that the dispersibility is poor and the filling amount cannot be increased. In addition to such a problem at the time of compositing, the carbon nanotube has a problem that it is difficult to handle because it has a low bulk density and is easily scattered.

For this reason, various attempts have been made to granulate carbon nanotubes (for example, Patent Documents 1 to 9).

JP-A-01-270543 Japanese Patent Laid-Open No. 03-056566 JP 2005-239531 A JP 2006-143532 A JP 2009-184849 A JP 2010-043169 A International Publication No. 2009/008516 Pamphlet JP 2011-084844 A International Publication No. 2013/054914 Pamphlet

However, with respect to the conventional granulated product of carbon nanotubes, sufficient studies have not yet been made in terms of suppressing scattering, improving dispersibility in thermoplastic resins and improving filling properties. Countermeasures such as kneading carbon nanotubes and thermoplastic resins with a biaxial kneader to make a so-called masterbatch have been taken in advance, but the fiber length is shortened when making a masterbatch. Problems occur.

The present invention has been made in view of the above circumstances. Carbon nanotube aggregates (structures) that improve the wettability of carbon nanotubes, are easy to knead, can suppress scattering, and are excellent in dispersibility and filling properties in thermoplastic resins. It is an object to provide a granular carbon nanotube) and a resin composition containing the same.

As a result of extensive research, the present inventor has reached the present invention. That is, the present invention is as follows.
[Carbon nanotube aggregates]
A carbon nanotube aggregate comprising carbon nanotubes and a water-soluble rosin resin.
[Thermoplastic resin composition]
A thermoplastic resin composition comprising a thermoplastic resin and the carbon nanotube aggregate.

Carbon nanotube aggregates containing carbon nanotubes and a water-soluble rosin resin improve workability such that the carbon nanotubes do not scatter when melt-mixed with a thermoplastic resin. Furthermore, the carbon nanotubes and the water-soluble rosin resin Therefore, carbon nanotubes mixed with a water-soluble rosin resin have good dispersibility in the molded product, and the resulting molded product has not only high tensile stress and elongation but also conductivity. high.

FIG. 1 is a schematic diagram of a wettability evaluation method. FIG. 2 shows the results of the wettability test of carbon nanotubes. A case where an aqueous solution containing 1% of a water-soluble rosin resin (REO30) is used, a case where only water is used, and a case where an emulsion rosin (rosin solid content with respect to water is 1%) are shown. In the figure, the result using an aqueous solution containing 1% of a water-soluble rosin resin is a curve of ●, the result of using only water is the curve of ■, and the result of using an emulsion rosin is a curve of ▲. is there. In the figure, the vertical axis represents penetration weight (g), and the horizontal axis represents time (minutes).

The carbon nanotube aggregate of the present invention contains carbon nanotubes and a water-soluble rosin resin. The carbon nanotube is a tube-like fiber made of carbon. The length of the carbon nanotube is usually 0.1 to 100 μm, preferably 5 to 50 μm, and the diameter is 1 to 80 nm, preferably 5 to 30 nm. It is a tubular fiber.

The water-soluble rosin resin used for the carbon nanotube aggregate of the present invention is a rosin obtained by modifying rosin so as to be water-soluble. Rosin is a non-volatile component of pine resin that is contained in a large amount in Pinaceae plants. Abietic acid, which is the main component, has a conjugated double bond, and consists of a highly hydrophobic site and a hydrophilic carboxyl group. The water-soluble rosin resin is not particularly limited, and can be obtained, for example, by adding alkylene oxide to this carboxyl group and esterifying it.

When polyethylene oxide or polypropylene oxide is used as the alkylene oxide, the polyethylene oxide is:
-(CH ₂ -CH ₂ -O) _n- ,
And polypropylene oxide is:
— (CH ₂ —CH (CH ₃ ) —O) _n —
And is added to the carboxyl group of rosin. Usually, n is 5 to 50, preferably 10 to 45. One molecule of the polyalkylene oxide is added to each carboxyl group of the compound constituting the rosin resin, and the polyalkylene oxide is added to most of the carboxyl groups.

Specific examples of water-soluble rosin resins made water-soluble obtained by adding polyethylene oxide include trade names REO15, REO30, and REO40 (all manufactured by Harima Chemical Co., Ltd.).

Rosin can be made water-soluble by other methods. As a method for making rosin water-soluble, it can be made water-soluble by, for example, saponification using an alkali.

The saponification can be performed by a usual method, and examples thereof include a method of saponifying rosin with caustic soda, alcohol amine, ammonia and the like. Specific examples of the saponified rosin include RX-20 manufactured by Harima Kasei Co., Ltd.

In the carbon nanotube aggregate of the present invention, the ratio of the carbon nanotube to the water-soluble rosin resin is usually 0.1 to 50% by weight, preferably 0.5 to 0.5% as the water-soluble rosin resin relative to the carbon nanotube. 20% by weight, more preferably 0.5 to 15% by weight. If the amount of the water-soluble rosin resin is too large, the amount of carbon nanotubes is relatively small, and the characteristics of the carbon nanotubes are difficult to appear. On the other hand, when the amount of the water-soluble rosin resin is too small, it becomes difficult to improve wettability and physical properties of the thermoplastic resin composition.

If necessary, the carbon nanotube aggregate can be added within the range that does not impair the original purpose, but it is preferable not to add it. Examples of the additive include a filler and a binder. If these additives are added too much, the physical properties deteriorate, so even if they are added, they are 0.1 to 5% by weight, for example, 0.1 to 1% by weight with respect to the carbon nanotubes.

The aggregate of carbon nanotubes can be obtained by mixing carbon nanotubes, a water-soluble rosin resin, and, if necessary, other additives. When mixing, add water and mix to form a clay-like kneaded product. The mixing method is not particularly limited, but is performed at a high speed of about 2000 rpm using a Henschel mixer or the like. The amount of water is not particularly limited as long as it becomes a clay-like kneaded material. For example, about 5 to 10 times as much water as the weight of the carbon nanotube is used.

When adding water, a water-soluble rosin resin may be dissolved in water to prepare an aqueous rosin solution and then mixed with carbon nanotubes, or after mixing a water-soluble rosin resin with carbon nanotubes, Water may be added.

The kneaded product obtained by mixing is formed into pellets of a predetermined shape by a wet extrusion granulator and dried to obtain carbon nanotube aggregates.

[Thermoplastic resin composition]
In order to obtain a high-performance composite material, the obtained carbon nanotube aggregate can be mixed with a thermoplastic resin to prepare a thermoplastic resin composition.

The thermoplastic resin is a thermoplastic resin that adds a function by an aggregate of carbon nanotubes, and is not particularly limited. Examples of the thermoplastic resin include polycarbonate resin and polyphenyl sulfide resin.

Preparation of carbon nanotube aggregate [Example 1]
Carbon nanotubes (C _TUBE- 199 manufactured by CNT Co., Ltd.) and 600 g of water were added to a 20 L Henschel mixer to make the volume about half that of the Henschel mixer. To this, 100 g of water-soluble rosin (trade name: REO30 Harima Kasei Co., Ltd., 30 mol of polyethylene oxide added) was added at a ratio of 5% by weight of water-soluble rosin to carbon nanotubes. The system resin was added and stirred and mixed at 2000 rpm for 2 minutes at high speed. The obtained mixture was a clay-like kneaded product, and this was put into a wet extrusion granulator manufactured by Dalton Co. to obtain a columnar granulated product (pellet). The obtained granulated product was dried at 90 ° C. for 2 hours with a blast dryer manufactured by Yamato Scientific Co., Ltd., to obtain a carbon nanotube aggregate. The obtained carbon nanotube aggregates were classified using a sieve having a nominal aperture of 2.36 mm as defined in JIS Z8801-1. The carbon nanotube aggregates that passed through the sieve were further classified using a sieve having a nominal opening of 1.18 mm. The carbon nanoaggregate remaining on the sieve was vacuum-dried at 80 ° C. to obtain the target carbon nanotube aggregate.

[Examples 2 to 5]
Carbon nanotubes and water-soluble rosin resin were mixed in the same procedure as in Example 1, and carbon nanotube aggregates of Examples 2 to 5 were prepared according to the ratios shown in Table 1. REO15 and REO40 are obtained by adding 15 mol% and 40 mol% of polyethylene oxide to rosin, respectively. For REO15, REO30, and REO40, the number of repeating units n of polyethylene oxide is about 15, about 30, and about 40, respectively.

[Example 6]
Using the water-soluble rosin resin obtained by saponification (trade name: RX-20, manufactured by Harima Kasei Co., Ltd.) as the water-soluble rosin resin, the carbon nanotube aggregate of Example 6 was prepared in the same manner as in Example 1. Was made. The blending ratio was created based on Table 1.

[Comparative Example 1]
A carbon nanotube aggregate of Comparative Example 1 was produced in the same manner as in Example 1 using emulsion rosin (ER) instead of the water-soluble rosin resin. ER was produced by the following method. That is, first, 100 g of modified rosin (trade name “135GN” manufactured by Harima Chemicals Co., Ltd.) was dissolved in 300 g of toluene to prepare a toluene solution of modified rosin. Next, 900 mL of an aqueous solution having an active ingredient concentration of 10% by mass in a surfactant (trade name “New Coal 2320-SN” manufactured by Nippon Emulsifier Industry Co., Ltd.) was separately prepared. Then, these were added to a toluene solution, mixed with stirring and emulsified. This was further made into a fine emulsion using a high-pressure emulsifier (manton Gaurin). Toluene was removed by heating and vacuum distillation of the obtained fine emulsion under conditions of 100 mmHg to obtain an emulsion rosin (ER) having a volume average particle size of 0.3 μm. The blending ratio was created based on Table 1.

[Wettability evaluation]
As shown in FIG. 1, a funnel 1 having a diameter of 15 mm was closed with a mesh 5 (hole size: 60 μm), and then powdered carbon nanotubes 2 (CNT Co., Ltd., C _TUBE- 199 manufactured by CNT Co.) were applied to the neck of the funnel. Stuffed. Thereafter, the mesh 5 was brought into contact with water or 1% binder solution 3. From the point of contact, measurement of the permeation time was started, and the wettability of the CNT and the binder was compared by measuring the weight of the solution immersed in the sample for each permeation time. The experiment was conducted using an aqueous solution containing 1% of a water-soluble rosin resin (REO30), water, and an emulsion rosin (with a solid content ratio of rosin of 1%; ER1%). It was found that the aqueous solution containing the functional rosin resin penetrates the carbon nanotubes very quickly and in large quantities (high wettability) (see FIG. 2). That is, it was found that the water-soluble rosin-based resin intervenes very easily.

[Preparation of thermoplastic resin compositions 1 to 11]
The carbon nanotube aggregates of Example 1 were mixed with polycarbonate resin (PC) or polyphenyl sulfide (PPS) in the proportions shown in Table 2, and were extruded by an extruder (PCM45) at a temperature in the range of 290 ° C. to 330 ° C. Then, extrusion molding was performed to obtain molded articles of the thermoplastic resin compositions 1 to 11 (prototype numbers 1 to 11). Table 3 shows the properties of the obtained thermoplastic resin composition. The thermoplastic resin composition 8 and the thermoplastic resin composition 9 have CNT Co. as carbon nanotubes. , Ltd. compression type carbon nanotubes (Comparative Example 2, trade name C _tube- 199P) and Kumho Petrochemical Co., Ltd. , Ltd. compression type carbon nanotubes (Comparative Example 3, trade name K-Nanos-100T) were used.

[Mechanical properties]
Mechanical properties were measured in accordance with ISO using a thermoplastic resin composition molded using a molding machine JSW80. The resistivity was measured using a press sheet having a diameter of 150 mmφ and a thickness of 0.9 mm, and a mold plate having a thickness of 90 × 50 mm and a thickness of 3 mm.

As shown in Table 3, the mechanical properties such as elongation and tensile stress were found to have the same or better properties than conventional CNTs.

[effect]
(1) About the carbon nanotube aggregate containing a carbon nanotube and water-soluble rosin resin, it is very easy to mix with the resin used as the base material of the functional resin, there is little scattering, and the dispersibility is also high. The water-soluble rosin resin has high wettability with the carbon nanotubes, can be mixed uniformly, and can be easily granulated.
(2) If the water-soluble rosin resin is contained in an amount of 0.1 to 50% by weight with respect to the carbon nanotube, the mechanical properties are further improved without deteriorating the properties of the CNT. Is also extremely useful.
(3) When the water-soluble rosin resin as a raw material shows neutrality when dissolved in water, for example, it exhibits alkalinity, tensile stress, elongation, etc. than a water-soluble rosin resin obtained by saponification The mechanical properties of are even better.
(4) If the water-soluble rosin resin is a polyethylene oxide adduct of rosin, a resin composition having high mechanical properties can be obtained.
(5) If the number of repeating units n of polyethylene oxide in the ethylene oxide adduct is 5 to 50, the water-soluble rosin resin is easy to handle and has an appropriate hydrophilicity, which is preferable.
(6) A thermoplastic resin composition obtained by melt-mixing the thermoplastic resin and the carbon nanotube aggregate according to any one of (1) to (5) includes a conventional granulated carbon nanotube. It is a resin composition having excellent mechanical properties as compared with the case of use.
(7) A method of granulating carbon nanotubes, comprising a step of mixing carbon nanotubes, water, and a water-soluble rosin resin, a step of extruding the mixture, and a step of drying the molded product. The carbon nanotubes can be granulated by a very simple method, and the functional resin composition produced using the obtained granulated carbon nanotubes has high mechanical properties and electrical conductivity. have.

Reference numerals shown in FIG. 1 indicate the following parts.
1 Funnel 2 Powder 3 Binder solution or water 4 Container 5 Mesh part

Claims

An aggregate of carbon nanotubes containing carbon nanotubes and a water-soluble rosin resin.
2. The carbon nanotube aggregate according to claim 1, comprising 0.1 to 50% by weight of the water-soluble rosin resin with respect to the carbon nanotube.
The carbon nanotube aggregate according to claim 1 or 2, wherein the water-soluble rosin resin as a raw material exhibits neutrality when dissolved in water.
The carbon nanotube aggregate according to any one of claims 1 to 3, wherein the water-soluble rosin resin is a polyethylene oxide adduct of rosin.
The carbon nanotube aggregate according to any one of claims 1 to 4, wherein the polyethylene oxide adduct has an ethylene oxide repeating unit number n of 5 to 50.
A thermoplastic resin composition obtained by melt-mixing a thermoplastic resin and the carbon nanotube aggregate according to any one of claims 1 to 5.
Mixing carbon nanotubes, water, and a water-soluble rosin resin;
Extruding the mixture;
A method of granulating carbon nanotubes, comprising a step of drying the molded product.