JP2019056087A - Polyurethane composite material and method for producing polyurethane composite material - Google Patents

Abstract

To provide a polyurethane composite material that comprises carbon nanotubes to have conductivity, while having excellent physical properties, and a method for producing a polyurethane composite material.SOLUTION: A polyurethane composite material contains polyurethane, and carbon nanotubes with an average diameter of 0.4 nm-230 nm. A content of the carbon nanotubes is 0.45 pts.mass-1.00 pts.mass relative to the polyurethane 100 pts.mass. The polyurethane composite material has a volume resistivity of 1.0×10(Ω cm)-9.0×10(Ω cm).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyurethane composite material having excellent electrical conductivity and a method for producing the polyurethane composite material.

  Carbon nanotubes are attracting attention for their electrical properties. A conductive polyurethane composition containing carbon nanotubes has been proposed (see, for example, Patent Document 1).

  However, in order to add conductivity to polyurethane, it is necessary to increase the compounding amount of carbon nanotubes. However, increasing the number of carbon nanotubes causes a decrease in the physical strength of polyurethane. In polyurethane applications that require electrical conductivity, for example, abrasion resistance may be required, but it is generally difficult to obtain electrical conductivity with carbon nanotubes while maintaining abrasion resistance.

  On the other hand, a technique for combining carbon nanotubes with rubber has been proposed by the inventors of the present application (for example, Patent Documents 2 and 3).

Special table 2012-520356 gazette JP 2005-97525 A Japanese Patent Laid-Open No. 2006-147992

  An object of the present invention is to provide a polyurethane composite material having excellent physical properties while imparting conductivity by blending carbon nanotubes and a method for producing the polyurethane composite material.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
The polyurethane composite material according to this application example is
A polyurethane composite material including polyurethane and carbon nanotubes having an average diameter of 0.4 nm to 230 nm,
The compounding amount of the carbon nanotube is 0.45 parts by mass to 1.00 parts by mass with respect to 100 parts by mass of the polyurethane.
The polyurethane composite material has a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm).

[Application Example 2]
In the polyurethane composite material according to this application example,
The carbon nanotube may be a multi-walled carbon nanotube having an average diameter of 5 nm to 100 nm.

[Application Example 3]
In the polyurethane composite material according to this application example,
The carbon nanotubes may be multi-walled carbon nanotubes having an average diameter of 5 nm to 20 nm.

[Application Example 4]
In the polyurethane composite material according to this application example,
The compounding amount of the carbon nanotubes may be 0.48 parts by mass to 0.97 parts by mass with respect to 100 parts by mass of the polyurethane.

[Application Example 5]
In the polyurethane composite material according to this application example,
The polyurethane composite material further includes an ionic liquid having conductivity,
The total amount of the carbon nanotubes and the ionic liquid with respect to 100 parts by mass of the polyurethane may be 0.45 parts by mass to 2.00 parts by mass.

[Application Example 6]
In the polyurethane composite material according to this application example,
The rate of increase in the amount of wear of the polyurethane composite material with respect to the amount of wear of the polyurethane alone in the Taber wear test after H-22 wear wheel, load 10N, 1000 rotations according to JIS K 7204 may be less than 110%.

[Application Example 7]
The method for producing a polyurethane composite material according to this application example is as follows:
A first mixing step of obtaining a first solution by mixing carbon nanotubes having an average diameter of 0.4 nm to 230 nm with respect to a liquid polyol;
After pressing and compressing the first solution while flowing, the pressure is released or decompressed to restore the original volume, and a defibrating step to obtain a second solution in which the carbon nanotubes are defibrated;
A second mixing step in which a liquid polyisocyanate is mixed with the second solution to obtain a third solution;
A reaction step of reacting a polyol and a polyisocyanate in the third solution to obtain a polyurethane composite material;
Including
The compounding amount of the carbon nanotubes in the first mixing step is 0.8 part by mass to 1.8 parts by mass with respect to 100 parts by mass of the polyol.
The polyurethane composite material has a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm).

[Application Example 8]
In the method for producing a polyurethane composite material according to this application example,
The second mixing step includes a step of mixing an ionic liquid having conductivity with the second solution,
The total amount of the carbon nanotube and the ionic liquid with respect to 100 parts by mass of polyurethane may be 0.45 parts by mass to 2.00 parts by mass.

[Application Example 9]
In the method for producing a polyurethane composite material according to this application example,
The defibrating step can be performed with a plurality of rolls having a roll interval of 0.001 mm to 0.01 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the polyurethane composite material which has the outstanding physical characteristic, mix | blending carbon nanotube and provided electroconductivity, and a polyurethane composite material can be provided.

It is a figure which shows typically the defibration process of the manufacturing method of the polyurethane composite material which concerns on one embodiment. It is a figure which shows typically the defibration process of the manufacturing method of the polyurethane composite material which concerns on one embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

A. Polyurethane Composite Material The polyurethane composite material according to the present embodiment includes polyurethane and carbon nanotubes having an average diameter of 0.4 nm to 230 nm, and the blending amount of the carbon nanotubes is set to 0.000 parts by mass with respect to 100 parts by mass of the polyurethane. 45 parts by mass to 1.00 parts by mass, and the polyurethane composite material has a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm). And

  The polyurethane composite material may further include an ionic liquid having conductivity. Further, the polyurethane composite material may contain known additives generally used for polyurethane in addition to the carbon nanotube and the ionic liquid.

A-1. Polyurethane Polyurethane (also referred to as urethane resin or urethane rubber) is a polymer compound containing a urethane bond. A urethane bond is produced | generated by reaction of an isocyanate group and a hydroxyl group. Polyurethane includes linear and branched ones.

  The isocyanate group for forming a urethane bond is supplied from a compound containing two or more isocyanate groups (referred to as polyisocyanate). Moreover, the hydroxyl group for forming a urethane bond is supplied from a compound (referred to as polyol) containing two or more hydroxyl groups. Polyurethane is industrially obtained by polyaddition reaction of polyisocyanate and polyol.

  In addition, polyurethane may contain bonds other than urethane bonds, for example, urea bonds (urea bonds) generated by reaction of isocyanate groups and amino groups, burette bonds generated by reaction of urea bonds and isocyanate groups, urethanes Examples include an alphanate bond generated by a reaction between a bond and an isocyanate group, and an isocyanurate bond formed by trimerization of an isocyanate group.

A-2. Carbon nanotube The carbon nanotube has an average diameter (fiber diameter) of 0.4 nm to 230 nm. Furthermore, the carbon nanotubes can be multi-walled carbon nanotubes having an average diameter (fiber diameter) of 5 nm to 100 nm, and can be multi-walled carbon nanotubes having an average diameter (fiber diameter) of 5 nm to 20 nm. If the carbon nanotube concentration is the same when the average diameter of the carbon nanotube is smaller, the number of carbon nanotubes per unit volume increases, and the cell structure formed by the carbon nanotubes also becomes finer. The physical identification of the material can be further improved, but the processability tends to decrease. The average diameter of the carbon nanotube can be measured by observation with an electron microscope. In the detailed description of the present invention, the average diameter and the average length of the carbon nanotubes are, for example, 5,000 times imaged by an electron microscope (the magnification can be appropriately changed according to the size of the carbon nanotubes), and the diameters and lengths of 200 or more locations. It can be obtained by measuring the thickness and calculating the arithmetic average value.

  The carbon nanotube may be subjected to a treatment for activating its surface.

  The compounding quantity of the carbon nanotube in a polyurethane composite material is 0.45 mass part-1.00 mass part with respect to 100 mass parts of polyurethane. Furthermore, the compounding amount of the carbon nanotube in the polyurethane composite material may be 0.48 to 0.97 parts by mass with respect to 100 parts by mass of polyurethane, particularly 0.60 to 0.85 parts by mass. Can be. If the blending amount of the carbon nanotube is 0.45 parts by mass or more, desired conductivity can be improved by defibrating the carbon nanotube. If the compounding amount of the carbon nanotube is 1.00 parts by mass or less, it can be processed (such as “second mixing step” described later). Moreover, if the compounding quantity of a carbon nanotube is 1.00 mass part or less, the fall of physical strength, especially the wear-resistant characteristic can be prevented. Here, the blending amount of polyurethane in the polyurethane composite material is a blending amount of components (polyol, polyisocyanate, butanediol, etc.) used for producing polyurethane.

  Carbon nanotubes are single-walled carbon nanotubes (SWNT: single-walled carbon nanotubes) and multi-walled carbon nanotubes (MWNT: multi-walled carbon) that are formed by winding one surface of graphite (graphene sheet) of carbon hexagonal mesh. Nanotubes). Multi-walled carbon nanotubes include double-walled carbon nanotubes (DWNT: double wall carbon nanotubes). A carbon material partially having a carbon nanotube structure can also be used. In addition to the name “carbon nanotube”, it may be called “graphite fibril nanotube” or “vapor-grown carbon fiber”.

  Carbon nanotubes can be obtained by vapor deposition. Vapor deposition is also called catalytic chemical vapor deposition (CCVD), which produces untreated carbon nanotubes by gas phase pyrolysis of hydrocarbons and other gases in the presence of a metal-based catalyst. Is the method. The vapor phase growth method will be described in more detail. For example, an organic compound such as benzene or toluene is used as a raw material, an organic transition metal compound such as ferrocene or nickelcene is used as a metal catalyst, and these are used together with a carrier gas at a high temperature such as 400 ° C. Introduced into a reaction furnace set at a reaction temperature of ˜1000 ° C., and floated on a floating reaction method (floating reaction method) for generating carbon nanotubes on the reaction furnace wall, or previously supported on ceramics such as alumina and magnesium oxide A catalyst-supporting reaction method (substrate reaction method) in which the metal-containing particles are brought into contact with a carbon-containing compound at a high temperature to generate carbon nanotubes on the substrate can be used.

  The carbon nanotubes can exist in a dispersed state throughout the polyurethane composite material. The defibrated state is a state where there is no aggregate of carbon nanotubes (a mass having a maximum diameter of 60 μm or more).

A-3. Ionic liquid An ionic liquid is a compound having a melting point of 100 ° C. or lower and consisting only of ions. In particular, it is preferable for a polyurethane composite material to be a compound consisting only of ions that are in a liquid state near room temperature.

  The ionic liquid is an ionic liquid having conductivity. The anion and cation of the ionic liquid are not limited, but are preferably non-metallic cations. Examples of the ionic liquid include organic nitrogen-based ionic liquid, titanium-based ionic liquid, lithium perchlorate-based ionic liquid, and the like.

  The total amount of the carbon nanotube and the ionic liquid added to 100 parts by mass of polyurethane in the polyurethane composite material may be 0.45 parts by mass to 2.00 parts by mass. Since the ionic liquid stabilizes the conductive effect of the carbon nanotubes, the ionic liquid may not necessarily be blended, but the stabilizing effect can be obtained with a small amount. The compounding quantity of an ionic liquid can be 0 mass part-1.00 mass part with respect to 100 mass parts of polyurethane, Furthermore, it can be 0.30 mass part-1.21 mass part.

A-4. Volume resistivity The polyurethane composite material has a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm). Further, the polyurethane composite material may have a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁵ (Ω · cm), and more particularly 1.0 × 10 ² (Ω · cm). cm) to 9.0 × 10 ⁴ (Ω · cm). According to the polyurethane composite material, a small amount of carbon nanotubes can be blended to impart conductivity. Therefore, the polyurethane composite material can be employed for antistatic applications.

The volume resistivity (Ω · cm) is a value indicating the electric resistance (Ω) per unit volume (1 cm × 1 cm × 1 cm). Since the polyurethane composite material has a volume resistivity of 1.0 × 10 ⁶ (Ω · cm) or less, it is measured by a constant current application method in accordance with JIS K 7194.

  The improvement in conductivity in polyurethane composite materials is due to the dispersal of carbon nanotubes dispersed in the polyurethane composite material, so that not only the conduction caused by the contact between carbon nanotubes but also the tunnel effect in the area where the carbon nanotubes are close to each other. It is presumed that this movement is caused. Compared to the case of using a semisolid polymer such as millable rubber, the distance between the closest points of carbon nanotubes in a polyurethane composite produced using a liquid polyol as a base material becomes smaller on average, so the tunnel effect It is presumed that the probability of occurrence is improved. In addition, it is speculated that the addition of conductive ionic liquids will contribute to the improvement of the probability of tunneling between adjacent carbon nanotubes, and ionic liquids are added to polyurethane composites that do not contain ionic liquids. Thus, the polyurethane composite material can ensure stable conductivity. Here, stable conductivity means that when a plurality of samples of a polyurethane composite material containing the same amount of the same components are prepared, the volume resistivity of each sample shows almost the same value between samples. This means that the variation in conductivity is small.

A-5. Taber abrasion test The Taber abrasion test measures the amount of abrasion of a test piece after 1000 rotations of an H-22 wear wheel, a load of 10 N according to JIS K7204. The rate of increase in the amount of wear of the polyurethane composite relative to the amount of wear of the polyurethane alone in the Taber abrasion test can be less than 110%. Further, the polyurethane composite material may have an increase rate of wear amount in the same test of 40% to 109%, and further 50% to 100% with respect to the wear amount of the polyurethane alone. Here, the test piece of the polyurethane simple substance was obtained under the same molding conditions with the same composition as the polyurethane component used in the polyurethane composite material. Conductive substances (carbon nanotubes, etc.) are not included in polyurethane single-piece test pieces. According to the polyurethane composite material, the deterioration of the excellent physical properties is small while blending the carbon nanotube and imparting conductivity.

A-6. Tensile test Polyurethane composite material has tensile strength (TS (MPa)) equal to or higher than that of polyurethane alone when tensile test is performed based on JIS K7127, and elongation at break (Eb (%)) is that of polyurethane alone. For example, it may be 110% to 150% with respect to the value of elongation at break of a single polyurethane. The polyurethane composite material can obtain the reinforcing effect of the carbon nanotubes and can improve the elongation at the time of cutting.

B. Method for Producing Polyurethane Composite Material A method for producing a polyurethane composite material according to this embodiment is a first mixing step in which a liquid polyol is mixed with carbon nanotubes having an average diameter of 0.4 nm to 230 nm to obtain a first solution. And after pressing and compressing the first solution while flowing, the pressure is released or reduced to restore the original volume, and a defibrating step of obtaining a second solution in which the carbon nanotubes are defibrated, A second mixing step in which a liquid polyisocyanate is mixed with two solutions to obtain a third solution, and a reaction step in which a polyol and polyisocyanate in the third solution are reacted to obtain a polyurethane composite material. The compounding amount of the carbon nanotubes in the first mixing step is 0.8 to 1.8 parts by mass with respect to 100 parts by mass of the polyol. The polyurethane composite material has a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm).

B-1. 1st mixing process A 1st mixing process is a process of mixing the carbon nanotube demonstrated by said A-2 with respect to a liquid polyol, and obtaining a 1st solution.

  The compounding quantity of a carbon nanotube is adjusted so that it may become 0.45 mass part-1.00 mass part with respect to 100 mass parts of polyurethane in a polyurethane composite material, and it mixes with a polyol. The compounding quantity of the carbon nanotube in a 1st mixing process is 0.8 mass part-1.8 mass parts with respect to 100 mass parts of polyols. Furthermore, the compounding quantity of a carbon nanotube can be 0.8 mass part-1.6 mass parts with respect to 100 mass parts of polyol, and can be 1.0 mass part-1.4 mass parts especially. . The polyurethane component in the polyurethane composite material is composed of polyisocyanate, polyol, and other polyurethane raw materials (such as a crosslinking agent). If the carbon nanotube is 1.8 or less, the processing tends to be easy in the second mixing step.

  In the first mixing step, the polyol is liquid. When the polyol is not liquid at room temperature, the first mixing step is performed at a temperature equal to or higher than the melting point of the polyol. Since the polyol is liquid, it is estimated that the conductivity is improved even with a small amount of carbon nanotubes.

  The first mixing step is a step until charging of the carbon nanofibers of a predetermined blending amount into the polyol is completed. Preferably, the operator visually recognizes that the carbon nanofibers are mixed with the whole polyol. It can be a process up to. More specifically, a predetermined amount of liquid polyol and carbon nanofibers placed in a container can be stirred manually or with a known stirrer.

The first solution obtained in the first mixing step is in a state where carbon nanofibers are individually distributed in a liquid (polyol) form. Depending on the wettability of the carbon nanofibers to the liquid, the liquid cannot be impregnated to the center of the carbon nanofiber aggregates, and the aggregates contain air. Carbon nanofibers cannot sufficiently constrain the molecular mobility of the liquid, and the carbon nanofiber aggregates and the liquid are easily separated from each other, and the structure is extremely unstable as a composite material. After the mixing step, the following defibrating step is performed on the first solution.

B-1-1. Polyol The polyol is not particularly limited as long as it is a compound having a bifunctional or higher functional hydroxyl group. Examples of the polyol include polyether polyol and polyester polyol.

  Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polypropylene triol, polypropylene tetraol, polytetramethylene glycol, polytetramethylene triol, polyalkylene glycols such as copolymers thereof, and side chains introduced into these. Examples thereof include derivatives, modified products, and mixtures thereof in which a branched structure is introduced.

  Examples of the polyester polyol include polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, polyethylene propylene adipate, polyethylene butylene adipate, polybutylene hexamethylene adipate, polydiethylene adipate, poly (polytetramethylene) adipate, Polyethylene azelate, polyethylene sebacate, polybutylene azelate, polybutylene sebacate, condensed polyester polyols such as polyethylene terephthalate, polycaprolactone diol, polycarbonate diol, derivatives that introduced side chains or branched structures into these, Examples thereof include a modified product and a mixture thereof.

B-2. Defibration process The defibration process is a process in which the first solution obtained in the first mixing process is pressurized and compressed while flowing, and then the pressure is released or reduced to restore the original volume to obtain the second solution. It is. The defibrating process is repeated a plurality of times. The defibrating step can be performed with a plurality of rolls having a roll interval of 0.001 mm to 0.01 mm. The defibrating process will be described with reference to FIGS. 1 and 2. FIG.1 and FIG.2 is a figure which shows a fibrillation process typically.

  FIG. 1 is a side view of the three roll 1. The three rolls 10, 20, and 30 rotate at predetermined rotational speeds V1, V2, and V3. The first solution obtained in the first mixing step is supplied from above the roll 10 on the left side of the figure, moves with the rotation of the roll 10 in the direction of arrow A1, and enters the nip between the roll 10 and the roll 20. Get in. The solution that has passed through the nip between the roll 10 and the roll 20 moves in the directions of arrows A2 and A3 along with the rotation of the roll 20, and then enters the nip between the roll 20 and the roll 30. Then, the solution passing through the nip between the roll 20 and the roll 30 moves in the direction of the arrow A4 along with the rotation of the roll 30, is taken out from the roll 30, and is supplied again to the roll 10 as shown by the arrow B1. Is done. Repeat this operation multiple times.

  As shown in FIGS. 1 and 2, the three rolls 1 have partition plates 50 and 52 at positions spaced apart from each other by a predetermined distance in the width direction (direction along the rotation axis) of the rolls 10 and 20. Since the nip between the rolls is narrow, the first solution gradually passes through the nip, so that the first solution that cannot enter the nip tends to spread in the width direction of the roll. The partition plates 50 and 52 prevent the first solution that cannot enter the nip from spreading beyond a predetermined width.

In the defibrating step, the roll interval (nip) between the rolls 10, 20, and 30 is 0.001 mm to 0.
. It can be performed with three rolls of 01 mm. Although three rolls are used here, the number of rolls is not particularly limited, and a plurality of rolls, for example, two rolls may be used. In that case, kneading is performed at the same roll interval. can do.

  In the defibrating step, the rotation ratio of the roll may be 1.2 to 3.0. This is because if the rotation ratio of the roll is large, the shearing force is increased in the first solution and acts as a force for separating the carbon nanofibers from each other. The rotation ratio of a roll here is a rotation ratio of an adjacent roll. That is, assuming that the surface speed of the roll 10 is V1, the surface speed of the roll 20 is V2, and the surface speed of the roll 30 is V3, the surface speed ratio (V2 / V1) of the rolls 10 and 20 is V2 = 1. = 1.2 to 3.0, and the surface speed ratio (V3 / V2) of the rolls 20 and 30 is in the range of V3 = 1.2 to 3.0 when V2 = 1. You can choose.

  The first solution supplied to the roll 10 enters a very narrow nip between the roll 10 and the roll 20 and is pressurized while flowing according to the rotation ratio of the roll. Since the movement of the first solution in the width direction of the roll 10 is restricted by the partition plates 50 and 52, a predetermined volume is sequentially supplied to the nip, and the volume is reduced by being compressed in the nip. Thereafter, when the first solution passes through the nip and moves along the arrow A2 of the roll 20, the pressure is released or reduced to restore the original volume. As the volume is restored, the carbon nanofibers flow greatly, and the aggregated carbon nanofibers are loosened.

  In addition, the first solution is subjected to the same pressurization, compression, release, and restoration in a very narrow nip between the next roll 20 and the roll 30, so that the aggregated carbon nanofibers are further loosened.

  Further, by repeating the series of steps from the roll 10 to the roll 30 a plurality of times, the carbon nanofibers in the first solution are defibrated and a second solution can be obtained. The defibrating step can be performed, for example, for 3 minutes to 10 minutes. The defibrating process can be performed 10 to 30 times, for example, when a series of processes is performed once.

  In the defibrating step, the kneading temperature (temperature of the first solution) can be set in accordance with the melting point of the polyol of the first solution. When the melting point of the polyol of the first solution is not more than room temperature, the kneading temperature in the defibrating step can be performed in the range of 0 ° C to 60 ° C, and further the kneading temperature is performed in the range of 15 ° C to 50 ° C. Can do. When the melting point of the polyol of the first solution is higher than room temperature, the kneading temperature in the defibrating step can be performed at a temperature not lower than the melting point and not higher than 30 ° C. above the melting point. Since the defibrating process is performed using the bulk modulus of the liquid, it is preferable to perform it at as low a temperature as possible within the range where the first solution is liquid. The bulk modulus is proportional to the Young's modulus and is the reciprocal of the compressibility. This is because the Young's modulus decreases with increasing temperature and the compressibility increases with increasing temperature, and the bulk modulus also decreases with increasing temperature. Therefore, the temperature of the first solution is preferably 60 ° C. or lower, preferably 50 ° C. or lower. The temperature of the first solution is preferably 0 ° C. or higher, preferably 15 ° C. or higher, from the viewpoint of productivity. This is because, when the temperature of the roll is low, for example, a problem of condensation in the roll occurs.

  The defibrating step is not limited to kneading with a roll such as a three roll, but may be any other method as long as it can be restored after the volume of the first solution is compressed. For example, it is possible to use a dispersing device such as a homogenizer that pressurizes and compresses the first solution to generate cavitation or turbulent flow and then rapidly reduces the pressure.

Due to the shear force obtained in the defibration process, a high shear force acts on the liquid, and the aggregated carbon nanofibers are gradually separated from each other by being repeatedly passed through the roll 1,
A polyurethane composite material that has been defibrated and dispersed in the first solution and has excellent dispersibility and dispersion stability of carbon nanofibers (the carbon nanofibers are difficult to reaggregate) can be obtained. Therefore, the polyurethane composite material obtained by the present production method can be applied to a wide variety of uses because the problem caused by the aggregate of carbon nanofibers does not occur.

  The second solution obtained in the defibrating step is preferably liquid or pasty. This is to facilitate mixing with the polyisocyanate in the second mixing step. Even if the second solution does not flow due to its own weight at room temperature, for example, when the viscosity can be decreased by an external force applied during temperature increase or mixing, the subsequent mixing step can be performed. Since the second solution is liquid or pasty, it does not flow when the amount of carbon nanotubes increases, so the carbon nanotubes exceed 1.8 parts by mass with respect to 100 parts by mass of the polyol in the first solution. It can be adjusted within a range. In order to make the second liquid into a liquid or paste, it can be adjusted so as to be the blending amount of the carbon nanotubes described in A-2 and B-1.

B-3. Second Mixing Step The second mixing step is a step of obtaining a third solution by mixing liquid polyisocyanate with the second solution. A 2nd mixing process may mix | blend the component for producing | generating polyurethanes other than polyisocyanate. The second mixing step can include a step of mixing the ionic liquid with the second solution.

  In the second mixing step, the second solution, polyisocyanate, and ionic liquid can be mixed in a liquid state. Therefore, when any of the polyol, polyisocyanate and ionic liquid is solid at room temperature, it can be mixed by heating to a temperature equal to or higher than its melting point.

  The second mixing step can be performed using, for example, a two-roll, three-roll, self-revolving mixer (planetary mixer) or the like.

B-3-1. Polyisocyanate Polyisocyanate is not particularly limited as long as it is a bifunctional or higher isocyanate group-containing compound. Examples of the polyisocyanate include aliphatic polyisocyanate, aromatic polyisocyanate, and alicyclic polyisocyanate.

  Examples of the aliphatic polyisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 1,3,6-hexamethylene triisocyanate. Etc.

  Examples of the aromatic polyisocyanate include 1,4-phenylene diisocyanate (PPDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 2,4. '-Diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 1,5-naphthalene diisocyanate (NDI), o-tolylene diisocyanate (TODI), crude TDI And polyphenylmethane polyisocyanate (crude MDI).

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexane-2,4-diisocyanate, 1,4-bis (2
-Isocyanatoethyl) cyclohexane and the like.

  These polyisocyanates may be used as a mixture of plural kinds.

B-3-2. Ionic liquid As the ionic liquid, the ionic liquid having conductivity described in A-3 can be used. About the compounding quantity of an ionic liquid, it is as having demonstrated said A-3.

B-3-3. Other raw materials In the second mixing step, other raw materials used for producing polyurethane may be mixed in addition to the polyol described in B-1-1 and the polyisocyanate described in B-3-1. . Examples of other raw materials include a crosslinking agent, a catalyst, and a plasticizer. As the crosslinking agent, short-chain alcohols and short-chain amines are used. For example, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 3 , 3′-dichloro-4,4′-diaminodiphenylmethane (MOCA) and the like. Examples of the catalyst include triethylenediamine (TEDA) and dibutyltin dilaurate (DBTDL).

B-4. Reaction Step The reaction step is a step of obtaining a polyurethane composite material by reacting the polyol and the polyisocyanate in the third solution obtained in B-3. The reaction process may be started in the second mixing process. The reaction step can include a step of injecting the third solution into the mold.

  The polyurethane composite material obtained by the reaction process has excellent physical properties while blending carbon nanotubes and imparting conductivity. The polyurethane composite material obtained by the reaction step can be the polyurethane composite material described in A above.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

(1) Sample Preparation First Mixing Step: Carbon nanotubes (MWCNT) were charged into a polyol in a container and stirred manually to obtain a first solution (1,4-butanediol as a crosslinking agent in the polyol). May be mixed in advance). The compounding quantity of the carbon nanotube was determined so that it might become the mass part (phr) shown in Table 1-Table 6 with respect to 100 mass parts (phr) of the polyol in each sample. “The amount of MWCNT added to 100 phr of polyurethane” in Tables 1 to 6 is the amount of carbon nanotubes added to 100 parts by mass of the polyurethane component (polyol, polyisocyanate, 1,4-butanediol). In Tables 4 and 5, “the blending amount of MWCNT and ionic liquid with respect to 100 phr of polyurethane” is the total blending amount of carbon nanotubes and conductive ionic liquid with respect to 100 parts by mass of the polyurethane component. Moreover, "the compounding quantity of the electroconductive component with respect to 100 phr of polyurethane" in Table 3 and Table 6 is a total compounding quantity of ketjen black and an ionic liquid which are electroconductive components with respect to 100 mass parts of polyurethane components. Comparative Example 1 is a single polyurethane, and in Comparative Examples 2-4 and 6-8, ketjen black generally used as a conductive material was mixed instead of carbon nanotubes.

  Defibration process: The first solution of each sample was put into a three roll (roll temperature 23 to 40 ° C.) having a roll diameter of 50 mm and kneaded for 3 to 10 minutes to obtain a second solution (three rolls) (See FIGS. 1 and 2). The roll interval was 0.001 mm to less than 0.01 mm. The roll speed ratio was V2 = 1.8 and V3 = 3.3 when V1 = 1 in FIG.

  Second mixing step: Add the second solution of each sample to the same three rolls as in the defibration step, and add isocyanate, 1,4-butanediol and conductive ionic liquid (ionic liquid-1, 2). And mixed to obtain a third solution. The first solutions of Examples 1 to 11 showed fluidity and could be mixed in the second mixing step.

  Reaction process: Before fluidity | liquidity fell, the 3rd solution was inject | poured into the metal mold | die and it was made to harden and react and obtained the polyurethane composite material sample of Examples 1-11 and Comparative Examples 1-8.

The compounding agents shown in Tables 1 to 6 below are
Polyol: Hodogaya Chemical Industries, polyether polyol PTGL1000, molecular weight 1000,
Multi-walled carbon nanotube (MWCNT): average diameter 10 nm,
Ketjen Black: Lion Specialty Chemicals, KB600JD,
Ionic liquid-1: US600 (organic nitrogen-based ionic liquid) manufactured by Taoka Chemical Co., Ltd.
Ionic liquid-2: Nippon Carlit Co., Ltd. PEL20A (lithium perchlorate ionic liquid),
(The average diameter is a value obtained by arithmetically averaging measured values at 200 or more locations using the imaging of a scanning electron microscope.

  In the second mixing step, all examples and comparative examples were prepared by using polyisocyanate (Cosmonate PH, melting point 37, manufactured by Mitsui Chemicals Co., Ltd.) with respect to 100 parts by mass of polyol as a polyurethane component, in addition to the formulations shown in Tables 1 to 6. 55.6 parts by mass of 1 ° C.) and 10 parts by mass of 1,4-butanediol (1,4-butanediol, viscosity 65 mPa · s (25 ° C.) manufactured by BASF Idemitsu).

(2) Tensile test For samples of Examples and Comparative Examples (test pieces punched into JIS No. 7 dumbbell shape), using a Shimadzu Corporation Autograph AG-X tensile tester, 23 ± 2 ° C, standard line A tensile test was performed in accordance with JIS K7127 at a distance of 10 mm and a tensile speed of 50 mm / min, and tensile strength (TS (MPa)) and elongation at break (Eb (%)) were measured. The measurement results are shown in Tables 1 to 6.

  The fracture surface of the tensile test was observed with an electron microscope. No agglomerates of carbon nanotubes were found on the fracture surfaces of the samples of Examples 1-11.

(3) Taber abrasion test About the sample of the Example and the comparative example, the Taber abrasion test was implemented based on JISK7204. In this test, a Taber abrasion tester manufactured by Taber Co., Ltd. was used, and the amount of wear (mg) was measured after 1000 rotations with an H-22 wear wheel and a load of 10N. The measurement results are shown in Tables 1 to 6. The wear amount of the polyurethane alone in Comparative Example 1 was 40 mg. The rate of increase in the amount of wear of the polyurethane composite material of each sample relative to the amount of wear (40 mg) of the polyurethane alone of Comparative Example 1 was calculated ((wear amount of each sample−40 mg) / 40 mg × 100). The rate of increase in wear (%) ".

(4) Measurement of volume resistivity The volume resistivity was measured about the sample (50 mm x 50 mm x 2 mm) of the Example and the comparative example. About Comparative Examples 1-4 and 6-8, since it is higher than 1.0 * 10 < ⁶ > ((omega | ohm) * cm), Mitsubishi Chemical Analytech Co., Ltd. high resistance resistivity measuring device MCP- is used as "volume resistivity-1". Using HT450 (measurement voltage 10 V), measurement was performed by a constant voltage application / leakage current measurement method in accordance with JIS K6911. Moreover, about Examples 1-11 and Comparative Example 5,
Since it is lower than 1.0 × 10 ⁶ (Ω · cm), JIS K is used as a “volume resistivity-2” using a low resistivity meter MCP-T610 (measurement voltage 90 V) manufactured by Mitsubishi Chemical Analytech.
In accordance with 7194, measurement was performed by a constant current application method. The measurement results are shown in Tables 1 to 6.

  According to the results of Tables 1 to 6, the polyurethane composite material samples of Examples 1 to 11 have a tensile strength equal to or higher than that of the sample of Comparative Example 1, and the elongation at break is greatly improved. Excellent characteristics. In particular, the samples of Examples 1 to 11 had higher tensile strength than the sample of Comparative Example 4 in which a large amount of ketjen black was added to improve conductivity.

  The samples of Examples 1 to 11 had a smaller amount of Taber abrasion than the sample of Comparative Example 4. Moreover, the abrasion loss of the samples of Examples 1 to 11 was smaller than the abrasion loss of Comparative Example 4, and the rate of increase in the abrasion loss was 100% or less.

The volume resistivity of the polyurethane composite material samples of Examples 1 to 11 is also 6.8 × 10 ⁴ (Ω · cm) at the maximum, and the conductivity can be improved efficiently by blending a small amount of carbon nanotubes. It was.

  1 ... 3 rolls 10, 20, 30 ... roll, 50, 52 ... partition plate, V1, V2, V3 ... rotational speed, A1 to A4, B1 ... arrow

Claims (9)

A polyurethane composite material including polyurethane and carbon nanotubes having an average diameter of 0.4 nm to 230 nm,
The compounding amount of the carbon nanotube is 0.45 parts by mass to 1.00 parts by mass with respect to 100 parts by mass of the polyurethane.
The polyurethane composite material is a polyurethane composite material having a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm). In claim 1,
The carbon nanotube is a polyurethane composite material which is a multi-walled carbon nanotube having an average diameter of 5 nm to 100 nm. In claim 1 or 2,
The carbon nanotube is a polyurethane composite material which is a multi-walled carbon nanotube having an average diameter of 5 nm to 20 nm. In any one of Claims 1-3,
The compounding quantity of the said carbon nanotube is a polyurethane composite material which is 0.48 mass part-0.97 mass part with respect to 100 mass parts of said polyurethanes. In any one of Claims 1-4,
The polyurethane composite material further includes an ionic liquid having conductivity,
The total of the compounding quantity of the said carbon nanotube and the said ionic liquid with respect to 100 mass parts of said polyurethanes is a polyurethane composite material which is 0.45 mass parts-2.00 mass parts. In any one of Claims 1-5,
A polyurethane composite material in which the rate of increase in the amount of wear of the polyurethane composite material with respect to the amount of wear of the polyurethane alone in the Taber wear test after 1000 revolutions in H-22 wear wheel according to JIS K 7204 is less than 110% . A first mixing step of obtaining a first solution by mixing carbon nanotubes having an average diameter of 0.4 nm to 230 nm with respect to a liquid polyol;
After pressing and compressing the first solution while flowing, the pressure is released or decompressed to restore the original volume, and a defibrating step to obtain a second solution in which the carbon nanotubes are defibrated;
A second mixing step in which a liquid polyisocyanate is mixed with the second solution to obtain a third solution;
A reaction step of reacting a polyol and a polyisocyanate in the third solution to obtain a polyurethane composite material;
Including
The compounding amount of the carbon nanotubes in the first mixing step is 0.8 part by mass to 1.8 parts by mass with respect to 100 parts by mass of the polyol.
The polyurethane composite material is a method for producing a polyurethane composite material having a volume resistivity of 1.0 × 10 ² (Ω · cm) to 9.0 × 10 ⁶ (Ω · cm). In claim 7,
The second mixing step includes a step of mixing an ionic liquid having conductivity with the second solution,
The total of the compounding quantity of the said carbon nanotube and the said ionic liquid with respect to 100 mass parts of polyurethanes is a manufacturing method of a polyurethane composite material which is 0.45 mass parts-2.00 mass parts. In claim 7 or 8,
The said defibration process is a manufacturing method of the polyurethane composite material performed with a several roll whose roll space | interval is 0.001 mm-0.01 mm.

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