JPS60191011A - Modified carbonaceous material - Google Patents

Abstract

PURPOSE:To obtain the titled material used for composite materials and having excellent affinity for matrices by treating the surface of carbon of a carbonaceous material consisting of hexagonal carbon network with gaseous fluorine. CONSTITUTION:The surface of carbon of a carbonaceous material consisting of hexagonal carbon network such as graphite, carbon black, carbon fiber, etc. is treated at 1-500mm.Hg partial pressure of fluorine for 0.5min-1hr by placing the carbon into a cylindrical reactor equipped with a mesh plate and an agitator, etc. which is arranged in a thermostat at -80-50 deg.C, keeping the inside of the reactor under vacuum, and introducing gaseous fluorine, which is diluted with an inert gas such as N2 and Ar and the gas such as air and O2 at need, from the lower part of the mesh plate. The titled material used for composite materials is obtained in this way.

Description

[Detailed description of the invention] The present invention relates to modified carbon materials for composite materials.

More specifically, the present invention relates to modified carbon for composite materials in which the carbon surface is treated with fluorine gas at -80 to 50°C to improve affinity with the matrix.

Carbon has excellent properties such as heat resistance, corrosion resistance, heat conductivity, and electrical conductivity, and its applications are extremely wide, and it is used in almost every industrial field. They come in a wide variety of forms. Especially recently, as represented by carbon fiber car pump hooks.

It has become more common to use it alone, or to fill it with plastics, rubber, etc. and use it as a composite.

Examples include graphite added to oil and plastics as solid lubricants, carbon fibers added to plastics and metals as reinforcing fibers, carbon black and carbon fibers added to plastics, rubber, etc. as conductive materials.

However, carbon generally has poor affinity with the matrix, causing a decrease in the mechanical strength and performance of the composite material. Therefore, wet treatment with nitric acid or cynic acid, air oxidation,
Polymer coating, silane treatment, etc. have been used, but a perfect method has not yet been found.

The present inventors attempted to treat the carbon surface with fluorine gas for the purpose of improving the affinity between carbon and the matrix, and found that the affinity was significantly improved, leading to the completion of the present invention.

Therefore, one object of the present invention is to provide a modified carbon material that has improved affinity with a matrix when the carbon material is mixed with resin, rubber, oil, etc. and used.

According to the present invention, a modified carbon material can be obtained by subjecting the carbon material to surface treatment with fluorine gas.

The carbon material referred to in the present invention is applied to all materials composed of carbon hexagonal networks such as graphite, carbon black, carbon fiber, graphite fiber, and expanded graphite. In other words, in these hexagonal networks, the carbon atoms on the crystal end faces are as follows:
It has free valences that cannot be satisfied by bonding with inner carbon atoms, and these carbon atoms are saturated by bonding with other heteroatoms, and the surface of all carbon materials is -0-H.

-0HO1-(!OH, -000H, -0=O, etc. are formed. Therefore, the treatment effect of fluorine gas according to the present invention is that the fluorine reacted with these functional groups contributes to the improvement of affinity. Therefore, it can be applied to all of the above carbon materials.

The fluorine treatment temperature in the present invention is -80 to 50°C, but since some carbon materials react with fluorine gas to form stable O-7 covalent bonds, the temperature is generally 20°C. A temperature range below .degree. C. in which no a-F covalent bond formation occurs is safe.

The formation of this O-F covalent bond is contrary to the purpose of the present invention, and the affinity with the matrix is significantly lowered by 1 degree. Therefore, it is easily influenced by the type of carbon material used, especially its surface area. For relatively thick materials, the temperature is preferably 0° C. or lower, and for materials with relatively small surface areas, such as graphite, it is desirable to perform the fluorine treatment at air temperature or higher.

In addition, as long as fluorine is uniformly supplied to the carbon material, a short treatment time is sufficient; even if the treatment time is longer, no corresponding effect can be expected, so the treatment time is usually 0.5 minutes to 1 hour. Therefore, it is difficult to perform the fluorine treatment uniformly for less than 5 minutes, and a corresponding effect cannot be expected for more than 1 hour.

The fluorine concentration of the fluorine gas used in the present invention is not limited to %, but for the above-mentioned reasons, it is preferably in the range of about 1 to 500 mmH. Furthermore, the fluorine gas can be used alone or in combination with an inert gas such as nitrogen or argon. It can be used even if it contains gas such as oxygen. Furthermore, hydrogen fluoride gas does not react well with functional groups, so it cannot be applied to martial arts, and the effects of the present invention can only be achieved by fluorine gas treatment.

As described above, the modified carbon material of the present invention can improve its affinity with the carbon material matrix through simple treatment, and has great industrial significance.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited to the Examples.

Examples 1 to 3, Comparative Example 1 One piece of commercially available expanded graphite (Toyo Tan'A ■Cracked) was placed in a cylindrical reactor equipped with a mesh plate and a stirrer at the bottom of a constant temperature bath. After maintaining the vacuum, fluorine gas for treatment was introduced from the lower part of the mesh plate, and treatment was carried out under the fluorination conditions shown in Table 1. As a measure of the wettability of these modified graphites with water, the total specific gravity of the modified expanded graphite was measured using water using a vicinometer method. Immersion time in water is 10
The test time was 0 mHP (absolute pressure) for 5 hours.

The measurement results are shown in Cloth 1.

Comparative Example 2 The specific gravity of the expanded graphite used in Examples 1 to 3 was measured by the same method as in Examples 1 to 3, and the results are shown in pels.

Reference Example Table 1 shows the results when the expanded graphite used in Examples L to 3 was similarly fluorinated using hydrogen fluoride gas instead of fluorine gas.

As shown in Figure 1-4r, expanded graphite was treated with 7 elements,
When using water, the 40 power is improved, but when using HF gas, almost no conversion is observed.

Examples 4-5 Natural graphite 100F having an average particle size of 4 μm was treated under the fluorination conditions shown in Table 2 using the same equipment as in Examples 1-3. After adding 10 wt % of these modified graphite I to #350 diesel oil and dispersing it, 41% of the modified graphite was tested using a portable oil tester (manufactured by Shinko Zoki). Table 2 shows the i++++ results.

Comparison Example 3 The graphite used in Example 4.5 was baked in the same manner as in Example 4.5, and the 4·t<=f nail was measured. The measurement results are shown in 2.

Clothing 2 Fluorine-treated graphite k ff'+' as shown in Table 2
When added to single slip oil, its 4"4 slip properties are superior compared to untreated.

Examples 6 to 8 Ten pieces of carbon fiber (0-106F manufactured by Kureha Chemical Industry Co., Ltd.) were treated under the fluorination conditions shown in Table 3 using the same equipment as in Examples 1-5. OF RP (Carbon Fiber Reinf) by the following method.
orced Plastic) k made.

Using 100 parts of Epikote 828 (manufactured by ?t1+ Shell) as an epoxy resin and adding 10 parts by weight of benzyldimethylamine as a hardening agent, 60% by weight of the above modified fibers were arranged in one direction at 90°C for 4 hours at 150°C. ℃24
It was heated for a period of time to form a molded product.

The bending strength was measured using a universal material testing machine (Shimadzu, Autograph D).
08-2000). The measurement results are shown in Cloth 3.

Comparative Example 4 Using the carbon fibers used in Examples 6 to 8, Examples 6 to B
Using the same method, 90FRP was made and its 111 strength was measured. The measurement results are shown in Table 3.

Comparative Example 5 The carbon fibers used in Examples 6 to 8 were heated in 60% nitric acid at 120°C.
After performing the m treatment for 24 hours, the modified fibers were made into J50FRP metal sheets using the same method as in Examples 6 to 8, and their bending strength was measured. The measurement results are shown in Cloth 3.

When fluorine-treated fibers are added to the tree opening as shown in Table 3, the mechanical strength is superior to that of untreated fibers.

Claims (1)

[Claims] A modified carbon material for composite materials, characterized in that it is treated with fluorine gas at a carbon IAH surface tl--so~50°C.