JPS6050739B2 - Fluorinated graphite molded body and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorinated graphite molded product which has an extremely high quality and excellent mixing and dispersibility with other substances, and a method for producing the same.

Fluorinated graphite is a layered inorganic polymer compound in which fluorine atoms and carbon atoms are bonded in a hexagonal network, and its properties include low surface energy, lubricity, and heat resistance.
The bond between them is strong and completely chemically stable, but under certain special conditions, the de-F reaction will proceed, and these characteristics can be used to create solid lubricants, antifouling agents, mold release agents, etc. It has been widely applied industrially to water and oil repellents, battery active materials, etc.

However, due to its unusually low surface energy, footed graphite has extremely poor formability compared to other fluorine-based materials or other layered compounds, and also has the disadvantage of considerably poor mixing and dispersibility with other materials. Therefore, in the development of applications, many efforts have been made to improve the above properties.

For example, in the invention described in JP-A-50-70295, fluorinated graphite and tetrafluoroethylene are reacted to form thread-like PHFE between fluorinated graphite particles, thereby imparting moldability. Attempts are being made.
Furthermore, the invention described in Japanese Patent Application Laid-Open No. 49-11646 attempts to coat fluorinated graphite with a caking substance such as wax or oil to improve the stability of the coating on lubricated surfaces. Unexamined Japanese Patent Publication 1973
In the invention described in JP-43663, the dispersibility of graphite fluoride is improved by adding colloidal oxides such as silica and alumina. However, the formability of fluorinated graphite can be improved by adding other substances or simply coexisting with them.
This method is intended to improve dispersibility, and although it is more reliable, it is difficult to say that it is an essential method, and its effects are not significant.

That is, in the method described in JP-A-50-70295, in order to blend fluorinated graphite with PTFE, TFE is usually
A PTFE aqueous dispersion obtained by emulsion polymerization of (tetrafluoroethylene) is used, but since graphite fluoride has extremely high water repellency, graphite fluoride is pre-mixed with an organic material with a strong affinity for water. It is necessary to add the PTFE by suspending it in a solvent, and in order to sufficiently wet the fluorinated graphite, a large amount of organic solvent is required, which causes coagulation of the PTFE particles and the formation of large agglomerates, making it difficult to mix the powder uniformly. It is something that the body cannot obtain.

Furthermore, this large coagulum was highly adhesive and difficult to crush, and if compression molded as it was, the pressure would not be applied uniformly, which would easily cause internal distortion, making it impossible to obtain a good molded product. . Also, JP-A-49-11646? In the method described in the publication, a caking substance such as wax is coated on the surface of the fluorinated graphite particles by mere physical bonding such as adsorption or adhesion, and it is not necessarily stable in various usage modes. It has the disadvantage that it does not remain coated, and that it is difficult to coat it uniformly.

Furthermore, in the case of such a method, it is almost impossible to minimize the amount of caking substance on the fluorinated graphite and coat it uniformly in order to fully exhibit the characteristics of the fluorinated graphite. It is. Furthermore, JP-A-47-43
The one described in No. 663 has the following characteristics in order to improve dispersibility:
Although a dispersant such as colloidal silica is used, due to its composition, when used as a molded product, there is an upper limit to the content of fluorinated graphite, and it is recommended that the content be no more than about 6% by weight. Therefore, the various properties of fluorinated graphite derived from surface energy cannot be effectively utilized.

In view of the above, the inventors of the present invention have conducted repeated research and have developed the so-called microencapsulation technique (coating treatment with a polymer is simply referred to as this for convenience). The present invention was based on the discovery that fluorinated graphite (hereinafter referred to as MC fluorinated graphite) treated by applying this method has excellent moldability and dispersibility.

In other words, the purpose of the present invention is to provide excellent film stability! The purpose is to obtain a uniform molded body of fluorinated graphite, which is obtained by pressure-molding fluorinated graphite that has been graft-bonded and microencapsulated with the vinyl resin of the present invention and a resin. and its manufacturing method.

What is fluorinated graphite used in the present invention (CF)n1(C2
F) In addition to what is represented by n, it also includes mixtures thereof in any proportion.

The fluorinated graphite of the present invention is microencapsulated by graft bonding of vinyl resin, and unlike simple adsorption or adhesion, the graft bond is to the extent that it cannot be separated by solvent extraction. It is bonded to the surface of fluorinated graphite in a strong bonding manner, resulting in an even coating.

The resin content can take any value, but in order to achieve good dispersibility, it must be at least about 0.5% by weight, and there is no upper limit, but in order to exhibit the physical properties of fluorinated graphite. For this purpose, it can be said that a salivary amount of up to about 5% is preferable. Therefore, even with a small amount of resin, the dispersibility for various resins is good. Such MC-formed fluorinated graphite can be molded as it is, but in the present invention, by further adding a resin to it, MC-formed graphite can be molded. Due to the good compatibility between fluorinated graphite and the resin, heat and pressure molding becomes easier, workability is extremely good, and strength can be increased. Various resins can be selected for the resin added later, unlike when converting to MC.
For example, polymethyl methacrylate, phenol resin, acetal resin, ABS resin, etc. can be appropriately selected and used depending on the purpose. There is no particular upper limit to the amount of resin added in this case, but in order to exhibit the performance of fluorinated graphite, it is recommended that the total amount of the graft resin and the later added resin be up to 100% of the fluorinated graphite. Since the fluorinated graphite of the present invention can be coated uniformly and firmly even with a small amount of resin, the characteristics of the fluorinated graphite can be maximized, and its uses are further expanded.

Note that the vinyl resin coating in the present invention is not limited to a complete coating of fluorinated graphite, but also includes one in which the fluorinated graphite surface is partially exposed. . Next, a method for manufacturing the molded article of the present invention will be explained. First, in a water-organic solvent mixed system or water-surfactant mixed system, fluorinated graphite powder and vinyl monomer are dispersed, and a polymerization reaction is performed in the presence of a water-soluble polymerization initiator to form fluorinated graphite. Microencapsulate with polymer. The organic solvent used here may be any water-soluble organic solvent.
Various alcohols such as methyl alcohol and ethyl alcohol, ketones such as acetone, ethers, amines, etc. are used, and as surfactants, any of anionic, cationic, and nonionic surfactants can be used. It may be a well-mixed system.

On the other hand, the vinyl monomer for forming the polymer coating the fluorinated graphite may be one that can be radically polymerized or radically copolymerized, such as acrylic acid, methacrylic acid, acrylate, methacrylic acid, Monomers having vinyl groups such as acrylic esters, methacrylic esters, acrylonitrile, N-methylolacrylamide, vinyl chloride, vinyl acetate, styrene, and divinylbenzene are used.

Water-soluble polymerization initiators include sulfuric acid yellow, sulfite aqueous solution, bisulfite solution, potassium persulfate, azobiscyanovaleric acid, ■-50 (2,2''-azobis-(2-amidinopropane)-dihydrochloride, Hikari Pure Chemical Industries, Ltd.) etc. are used.

In order to suitably carry out the present invention, 1 to 1 (4) parts by weight of an organic solvent, 1 to 50 parts by weight of a surfactant, 1 to 10 parts by weight of fluorinated graphite and a vinyl monomer are added to 100 parts by weight of water. Quantity 0.
1 to 100 parts by weight are added and thoroughly stirred and dispersed, and a polymerization initiator is added to the suspension thus obtained and stirred thoroughly. A sufficient amount of the polymerization initiator is used in the range of 0.01 to 20% by weight based on the vinyl monomer. The polymerization reaction of the present invention can be carried out at room temperature, but if it is desired to shorten the polymerization time, it is better to heat the reaction mixture to about 70°C. According to the present invention, a high polymerization rate can be obtained with a short polymerization time of about 11 to 5 hours. After the polymerization reaction is completed, the slurry of fluorinated graphite is separated, thoroughly washed with water, and the residue is dried.

If a resin is further added to the fluorinated graphite which has been made into MC with a vinyl resin of 0.5 to 0.5% by weight and then pressure molded, a molded body of fluorinated graphite can be easily obtained. The molding temperature varies depending on the type of vinyl monomer used and the type of resin added later, but it is usually 100-250°C, and the molding pressure is 150-40°C.
It is about 50k9/d. In the present invention, microcapsules can be formed with an extremely small amount of resin, so it can be molded freely using known molding methods, and products with a very large amount of fluorinated graphite can be molded, so the continuous film of the fluorinated graphite powder itself can be formed. You can also get something close. As described above, the MC-formed fluorinated graphite molded article of the present invention can be manufactured into a molded article made almost entirely of fluorinated graphite itself, and can also be flexibly adapted to complex shapes. , its performance far exceeds that of conventional ones.

In addition, if you want to expose the fluorinated graphite layer on the surface of the molded object and make the characteristics of fluorinated graphite stronger, you can remove the resin by grinding the surface of this molded object, or peel off the surface resin by solvent treatment. You can also do it.

Since the molded product according to the present invention can fully exhibit the characteristics of fluorinated graphite, it can be used in all applications where conventional fluorinated graphite is used, such as bearing materials, electrode materials, mold release materials, and resin dispersion molding. In cases where a molded product containing a high density of fluorinated graphite without requiring much strength is required, such as a lubricant, battery active material (anode material), or water repellent material, extremely It can be applied to fields where pollution, moisture, and oil are averse by reducing the amount of added resin. Furthermore, it goes without saying that various additives can be added to the molded article of the present invention depending on its use. Next, examples of the present invention will be given and explained in more detail.

Production of MC fluorinated graphite Production example 1 A three-neck flask with a capacity of 1 F was immersed in a constant temperature water bath maintained at 60'C, and 200ml of ethyl alcohol, 280ml of water
mL and fluorinated graphite (CF) NlOOg (300 mesh bath after crushing in a jet mill, micrograph is shown in the first page)
As shown in the figure.

), 25 g of methyl methacrylate were added, and while stirring and mixing, 20 ml of a 6% sulfite aqueous solution was added to carry out polymerization. The pH at this time is approximately 2. After 7 hours had passed since the addition of the sulfite aqueous solution, the reaction product was separated, thoroughly washed with water, and dried under vacuum at 80'C. The weight of this thing is 117.
As is clear from the micrograph shown in FIG. 2, the presence of fluorinated graphite or polymer alone was not observed, and the fluorinated graphite was well covered with the polymer.

Also. After extracting this product with benzene for a while, the infrared absorption spectra of the extracted product and the benzene-insoluble material were measured, and the patterns shown in FIGS. 5 and 6 were obtained, respectively. This confirmed that the extract was a homopolymer of polymethyl methacrylate, and that the benzene-insoluble portion also matched the spectrum of polymethyl methacrylate. From these results, it was confirmed that polymethyl methacrylate was graft-bonded to the surface of fluorinated graphite. Additionally, thermogravimetric analysis (TGA)
The content of polymethyl methacrylate was confirmed to be 15.1% by weight from the weight reduction by did.). Production Example 2 A 1' capacity three-necked flask was immersed in a constant temperature water bath maintained at 60°C, and 150ml of ethyl alcohol and 330ml of water were added.
m1 and fluorinated graphite (C2F) NlOOg (crushed in a jet mill, taken in a 250 mesh bath, shown in FIG. 3 as a micrograph.

), 30 g of polymethyl methacrylate was added, and while stirring, 20 mt of a 6% sulfite aqueous solution was added and weighed. The pH at this time is approximately 2. Three hours after the addition of the sulfurous acid aqueous solution, the reaction product was taken from house to house, thoroughly washed with water, and then vacuum-dried at 80°C. A microscopic photograph of this product is shown in FIG. In this way, the content of polymethyl methacrylate was 19. 124.7 g of a dry product with a weight of % was obtained. Production Example 3 A three-bottle flask with a capacity of 1e was immersed in a constant temperature water bath at 60'C, and 200ml of methyl alcohol, 28ml of water was added.
5 ml of fluorinated graphite (C2F)NlOOgl polymethyl methacrylate were added thereto, and while stirring, 15 ml of a 6% sulfite aqueous solution was added to carry out polymerization.

After 4 hours had passed since the addition of the sulfurous acid aqueous solution, the reaction product was separated, thoroughly washed with water, and then vacuum-dried at 70°C. In this way, the content of polymethyl methacrylate is 10. Heel weight% dry product 111. I got a change. Production Example 4 An 11-capacity three-bottle flask was placed in a constant temperature water bath at 600C. Soaked in 200 ml of ethyl alcohol, 280 ml of water and 30 ml of fluorinated graphite (CF) NlOOgl acrylonitrile.
10 g of V-50 (Wako Pure Chemical Industries) while stirring.
% aqueous solution was added to carry out polymerization.

After 3 hours from the addition of the aqueous solution of (1)-50, the reaction product was separated by PJ, thoroughly washed with water, and then dried under vacuum at 80°C. In this way, the content of polyacrylonitrile is 19. 123.9 g of a dry product with a weight of % was obtained. Manufacturing example 5
Immerse a 1f capacity three-bottle flask in a thermostatic water bath at 60°C, add 200ml of ethyl alcohol, 280Tn of water, 15g of fluorinated graphite (CF)NlOOg, 15g of polymethyl methacrylate, 15g of styrene while stirring, and add 20mt of 6% sulfite aqueous solution for polymerization. I did this.

Three hours after the addition of the sulfurous acid aqueous solution, the reaction product was separated, thoroughly washed with water, and then vacuum-dried at 80°C.
In this way, the content of the copolymer is 18. 122.5 g of a dry product with a weight of a% was obtained. Production Example 6 200 m of acetone was added to a 1' capacity three-necked flask at room temperature.
1. 280 ml of water and 10 g of fluorinated graphite (CF) NlOOgl polymethyl methacrylate were added, and while stirring and mixing, 10 ml of a 6% sulfite aqueous solution was added to carry out polymerization.

Five hours after the addition of the sulfite aqueous solution, the reaction product was separated, thoroughly washed with water, and then vacuum-dried at 70°C. In this way, the content of polymethyl methacrylate is 4
．． 105 g of a dry product containing 8% by weight was obtained. Production Example 7 Addition amount of polymethyl methacrylate was 5g, polymerization time was 3
Polymerization was carried out under the same conditions as Production Example 6 except for the time,
Dry product with polymethyl methacrylate content of 1% by heel weight 10
1.2g was obtained.

Example 1 Regarding the MC fluorinated graphite produced in Production Examples 1 to 7, the first
Dry mix resin powder with the composition shown in the table, 10g each.
Using a mold with a diameter of 50Tfrm, the molding temperature was 180℃,
Compression molding was performed at a molding pressure of 250k9/c.

All of these had good moldability, and there were no problems with demolding. These evaluation results are shown in Table 1. Comparative Example 1 Untreated fluorinated graphite and resin powder having the composition shown in Table 1 were dry mixed and compression molded in the same manner as in Example 1.

The results are shown in Table 1. Example 2 The MC fluorinated graphite of Production Example 6 was dry mixed with ABS resin, phenol resin, and acetal resin, and the mold temperature was 100~
Approximately 10 at 180°C1 molding pressure 150-200k9/d
A molded body was obtained by holding for a minute.

The P* value (product of pressure and velocity) and amount of wear of these molded bodies were measured using a Hayama type wear tester. The results are shown in Table 2. ×4 Comparative Example 2 ABS using untreated (CF)n
The resin, phenol resin, and acetal resin were dry mixed, and the P■ value and wear amount of the molded product prepared in the same manner as in Example 2 were measured in the same manner as in Example 2.

The results are shown in Table 2.

[Brief explanation of the drawing]

Figures 1 and 2 are micrographs of untreated (CF)n and polymer-coated (CF)n of Production Example 1, and Figures 3 and 4 are micrographs of untreated (CF)n and polymer-coated (CF)n of Production Example 2. O and polymer coating (
A micrograph of C2F)n is shown.

Claims (1)

[Claims] 1. A fluorinated graphite molded article made of fluorinated graphite whose surface is graft-bonded with a vinyl resin and a resin. 2 In a water-organic solvent mixture system or a water-surfactant system,
Fluorinated graphite and a vinyl monomer capable of radical polymerization or radical copolymerization are dispersed, polymerized in the presence of a water-soluble polymerization initiator, and a resin is further added to the resulting resin-grafted fluorinated graphite. 1. A method for producing a fluorinated graphite molded article, the method comprising molding the fluorinated graphite molded article.