JPS6323123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing carbon tubes used for feeding and blowing corrosive liquids or gases, as fillers in reaction vessels, as protection tubes, and the like.

Prior Art Carbon is used in various fields because it has excellent heat resistance, electrical conductivity, and corrosion resistance against chemicals.
Among these, carbon tubes are used as heating elements, Raschich tubes for filling hydrogen chloride reaction vessels, temperature measuring protection tubes for liquids and gases, gas blowing tubes into molten baths, and the like.

Carbon tubes are usually made by kneading powder such as coke or graphite with binder such as pitch or thermosetting resin, extruding it into a hollow shape, firing it, and graphitizing it if necessary, or by making it into blocks made from the above raw materials. A product is made by processing a graphitized product into a hollow shape. Since carbon tubes manufactured by these methods are air permeable, methods such as repeatedly impregnating the fired product with resin and re-firing are used to make it impermeable or impermeable. Therefore, these methods inevitably require complicated steps.

In addition to the above-mentioned raw materials, carbon products include so-called glassy carbon, which is made by carbonizing a thermosetting resin, and has been put to practical use in crucibles and the like. This product is made by carbonizing resin, and during the carbonization process, the resin decomposes and gas is generated, and unless this is controlled, it will not be possible to obtain an impermeable product. Therefore, the resin is made into a thin layer and hardened.
After firing, a resin is further applied on top of the resin, and the process of curing and firing is repeated to obtain a predetermined thickness. In practice, it is difficult to produce products with considerable thickness using this method.

OBJECTS OF THE INVENTION The object of the present invention is to provide an air-impermeable, impermeable glass-like carbon tube without going through the above-mentioned complicated steps.

Since this carbon tube is impermeable and impermeable, it is suitable for gas feeding, blowing, etc., as a temperature measuring protection tube for molten baths, and as a Raschig tube for hydrochloric acid synthesis.

Structure of the Invention The present invention involves applying or impregnating a thermosetting resin such as a phenol resin or a furan resin onto cellulose paper or cloth, rolling it onto a core material until it reaches a predetermined thickness, and then pulling out the core material to form a laminated tube. This method involves obtaining a carbon tube, hardening it, and finally firing it in a non-oxidizing atmosphere.

In the above carbon tube manufacturing method, by adding carbon filler such as carbon (including graphite, hereinafter the same) fine powder or carbon fiber to paper, cloth or resin,
It can be a carbon tube containing carbon filler.

Phenol resins and furan resins are preferred as thermosetting resins, and these are diluted with acetone, ethanol, etc., and used in the form of a liquid having an appropriate viscosity.
These resins may also be modified by adding other compounds, and in the case of phenolic resins, phenolic resins modified with drying oils such as tung oil and linseed oil are preferred. This is because when this resin is used, gas is gradually generated during the curing and firing process, for reasons that are not clear, and compared to other resins, it has the advantage of being able to prevent the formation of pores even if the heating rate is faster. Because there is.

Kraft paper, linter paper, etc. can be used as cellulose paper. There are no particular restrictions on the weave of the cloth. If carbon filler is desired to be included, it may be mixed into these papers or cloths. The carbon filler can also be added by dispersing fine carbon powder or fine carbon fibers in a resin and coating or impregnating it on paper or cloth.

If the amount of carbon filler is too large, the airtightness of the product will decrease, so it is recommended that the amount of carbon filler be 40% by weight or less in the product after firing.

To impregnate paper, etc. with resin, heat the paper, etc. to 100℃ in advance.
A method of drying the resin to a certain degree and then immersing it in a resin solution can be used. Dipping and pulling can also be carried out continuously. Further, the resin liquid may be applied to one or both sides of the paper. When applying, make sure that the liquid penetrates into the paper.

Paper impregnated or coated with resin is processed, for example, by passing it between rolls, in order to remove excess resin. and dry. The appropriate amount of resin to paper or cloth is 100 parts by weight for the former and 30 to 70 parts by weight for the latter.

Paper or cloth impregnated with resin, coated, and dried is formed into a tubular body by rolling. For forming, there are known mold tube and rolled tube methods as methods for forming laminated tubes. In the former case, a core material is selected according to the thickness of the pipe, and the paper, etc. is wrapped around it.
A hard chrome-plated iron rod is suitable for the heartwood, and is heated beforehand. The thickness of wrapping is determined according to the wall thickness of the pipe.

Once the rolling is complete, heat the resin with hot air at around 90 to 100 degrees Celsius to soften the resin. Then, it is inserted into a mold that has been preheated to about 140 to 160°C, and pressure is gradually applied to about 120 to 150 kg/cm ² . After the pressurization is completed, pull out the mandrel using a core removal machine while it is still hot. In this way, a laminated tube is obtained, and by making the shape of the mandrel square, polygonal, etc., a laminated tube of a corresponding shape can be obtained.

In the load tube method, paper coated on one side with resin is often used. This is preheated and rolled around the mandrel to a predetermined thickness while being hot-pressed using a hot roll and a pressure roll. After rolling, heat to around 120-140℃,
Pull out the mandrel.

The laminated tube thus manufactured is heated and fired. It is necessary to carry out the firing gradually, especially when the temperature is raised from 230 to 360°C, and preferably 1.5°C/hr or less. The subsequent firing is preferably carried out in a non-oxidizing atmosphere at a temperature increase rate of about 5 to 10°C/hr. The appropriate firing temperature is 800°C or higher, but graphitization treatment may be performed if necessary. Since the laminated tube is made of thermosetting resin during firing, it will not lose its shape and can be fired as is. The tube shrinks considerably during firing, so this must be taken into consideration when molding.

In the present invention, the cellulose fiber is carbonized and becomes one with the carbonized resin, but unlike other synthetic fibers, the cellulose fiber does not fuse with the resin and lose its fiber form, so it has a reinforcing effect. is large. Moreover, the inclusion of fibers facilitates the decomposition of resin and other gases during the firing process, and prevents the formation of pores in the product. There is so-called prepreg, which is a carbon fiber sheet impregnated with resin, but when it is carbonized, many pores are generated, making it difficult to make an air-impermeable carbon tube.

Effects of the invention In the present invention, paper or cloth is impregnated with resin,
Since the product is coated and laminated and pressed together in large numbers, the product becomes a dense, air-impermeable, impermeable glass-like carbon tube even after firing.

Example 1 A phenolic resin partially modified with tung oil was used as a binder. Mix 100 parts of tung oil, 150 parts of phenol, and 50 parts of nonylphenol and maintain at 50°C. to this
Add 0.5 part of sulfuric acid, stir, and gradually raise the temperature to 120℃.
The mixture was held for 1 hour to carry out an addition reaction between tung oil and phenol.

After that, the temperature was lowered to below 60℃, and 6 parts of hexamethylenetetramine and 100 parts of 37% formalin were added.
After reacting at 90°C for about 2 hours, the mixture was dehydrated in vacuum and diluted with 100 parts of methanol and 100 parts of acetone to obtain a varnish with a viscosity of 20 cps.

Using this as a binding material, impregnate kraft paper and wrap it 20 times using the rolled tube method.
Pull out the mandrel at ℃ and find that the wall thickness is 2 mm, the inner diameter is 2 cm, and the length is
A 100cm laminated tube was obtained. This was heated to 150°C in 1 hour and held for 1 hour to cure. Next, the temperature was raised to 1000°C in a nitrogen atmosphere for 100 hours to complete carbonization.

The characteristics of this carbon tube are as follows.

Wall thickness Air permeability Bending strength 1.5mm 8×10 ^-8 cm ² /sec 1500Kg/cm ² Electrical specific resistance 0.01Ω・cm Example 2 Phenol resin was used as the binder and diluted with acetone (viscosity approximately 27000cps). ), and further, 10% by weight of fine graphite powder (44 μm or less) was added and dispersed in the whole. The rest is the same as in Example 1.

The characteristics of this carbon tube are as follows.

Wall thickness Air permeability Bending strength 1.5mm 3×10 ^-7 cm ² /sec 1300Kg/cm ² Electrical resistivity 0.08Ω・cm

Claims (1)

[Claims] 1. Cellulose paper or cloth impregnated or coated with a thermosetting resin is wrapped and laminated on a core material,
A method for manufacturing a carbon tube, which comprises: then pulling out the core material to obtain a laminated tubular body, and firing the laminated tubular body in a non-oxidizing atmosphere. 2. The method for manufacturing a carbon tube according to claim 1, wherein the laminated tubular body contains a carbon filler.