JPH0567595B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing an impermeable carbon material that is impermeable to liquids, gases, and the like. [Prior Art] Impermeable carbon materials, which have been used in heat exchanger components and various sealing materials that require corrosion resistance, are produced by applying liquid thermosetting resin to the pore spaces of carbonaceous materials under reduced pressure. /Or manufactured by impregnating and filling under pressure and then heating and curing in the air or a pressurized atmosphere. However, when using the above method, it is not possible to impregnate the resin deep into the carbonaceous material, and furthermore, during the heating and curing process, the resin once filled may evaporate as unreacted components or water produced by polycondensation. A phenomenon occurs in which the material flows out from the pore spaces of the material, and this, together with volumetric shrinkage due to polycondensation of the filled resin, makes it extremely difficult to completely close the pore spaces. For this reason, currently, a complicated process that involves processing a carbonaceous material in advance into a shape as close to its final form as possible, and then repeating resin impregnation and heat curing processes multiple times, is considered a good solution. [Problems to be solved by the invention] Under these circumstances, with the current method, the production period becomes long (2 to 3 months) because production cannot begin until the product shape is determined; Furthermore, even after multiple resin impregnations and heat treatments, there were technical problems in that the resin filling layer was thin and its impermeability was easily lost when surface cutting was performed. The present invention was made with the aim of solving these problems of the conventional technology, and it is possible to reliably fill the deep part of the material with resin by one-time resin impregnation and heat curing, and therefore, the impregnation treatment can be performed while the unprocessed material is intact. The present invention provides a method for manufacturing an impermeable carbonaceous material that makes it possible to do this. [Means for Solving the Problems] That is, the method for producing an impermeable carbonaceous material according to the present invention involves placing a carbonaceous material in an impregnation tank, immersing it in a liquid thermosetting resin under reduced pressure, and then soaking the carbonaceous material in a liquid thermosetting resin. Switch to pressurized state until the liquid resin initially hardens.
The structural feature is that it is heat treated at a temperature of 30°C or higher. First, an unprocessed carbonaceous material is placed in an impregnation tank that is shaped to accommodate the material, and after the pressure is reduced to a predetermined degree of vacuum, a liquid thermosetting resin is poured into the tank to immerse the material. The thermosetting resin used for impregnation is usually
A phenol-based or furan-based initial condensation resin liquid (viscosity of 90 poise or less), which is commonly used for impregnating carbon materials, is used. Next, the inside of the impregnation tank is pressurized to 1 kg/cm ² or higher, and the outer periphery is heated to a temperature of 30° C. or higher to lower the resin viscosity while sufficiently impregnating the deep part of the pores. The heat treatment is continued until the liquid resin in the impregnation tank is initially cured. At this time, if the heating temperature is lower than 30°C, the initial curing of the resin will not proceed smoothly, making it extremely difficult to take out the impregnated material. Also,
Heating over 100℃ accelerates the initial hardening of the resin.
This is not preferable because it becomes a factor that inhibits deep impregnation. Therefore, it is desirable to set the heating temperature in the range of 30 to 100°C. The carbonaceous material that has been impregnated and initially hardened in this way is heated in the impregnating tank to a temperature of up to 180°C in the atmosphere to completely harden the resin. After the treatment, the carbonaceous material is taken out from the impregnation bath after being cooled, and the resin attached to the outer periphery is removed. At this time, the carbonaceous material is peeled off due to the difference in coefficient of thermal expansion during the cooling process, and can be easily taken out from the cured resin in the impregnation bath. [Function] According to the above process, the impregnation step is carried out under heat and pressure, so the viscosity is reduced and the resin is smoothly filled into the pores deep within the material. Since the heating and pressurization is carried out in the same way in the impregnation tank up to the stage of initial hardening, the outer peripheral portion of the material is always kept in a state where it is pressed by the resin. Through this action, the phenomenon of the impregnated resin flowing out from the pore space is effectively prevented, and the lack of filling caused by the volumetric contraction of the impregnated resin is sufficiently prevented by new penetration of the resin existing in the outer periphery. will be replenished. Based on such a mechanism, complete impermeability can be imparted to the carbonaceous material through a single impregnation treatment. [Example] Unprocessed carbonaceous material having a cylindrical shape with an outer diameter of 640 mm and a thickness of 600 mm (apparent specific gravity 17 g/cm ² , porosity 24
%) was placed in an impregnating tank with a sealed structure that could accommodate the material, and after reducing the pressure in the system to 5 torr, a 45 poise phenol formaldehyde resin solution was flowed in until the material was immersed. Next, the inside of the system was pressurized to 7 kg/cm ² and 70
The sample was maintained for 24 hours while being heated at a temperature of 0.degree. C. for impregnation, gelation, and initial hardening. After the treatment, the impregnating tank was heated in the air at a temperature of 180°C for 10 hours to completely cure the resin, and then the impregnated material was taken out from the tank. From the impervious carbon material obtained in this way,
1 plate with an outer diameter of 560 mm and a thickness of 170 mm, an outer diameter of 120 mm,
10 cylinders with an inner diameter of 75 mm and a length of 200 mm, and an outer diameter of 90
Eight cylinders with a diameter of 50 mm, an inner diameter of 50 mm, and a length of 200 mm were formed by cutting, and a leak test was conducted for 10 minutes by applying a nitrogen gas pressure of 4 kg/cm ² to these materials. This test was conducted on 10 pieces of the same carbonaceous material, and the results are shown in the table below, comparing the processing conditions and leakage test pass rate (no leaks pass). For comparison, examples in which conventional resin impregnation and heat curing operations were performed 1 to 3 times are also listed as conventional examples.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably fill the unprocessed carbonaceous material deep into the deep part with resin through one-time resin impregnation and initial curing treatment, and this can be processed into a predetermined shape and manufactured into a product. becomes possible. Therefore, impermeable carbon members such as heat exchange equipment or various sealing materials can be manufactured efficiently in a short construction period, which is extremely advantageous industrially.

Claims (1)

[Claims] 1 Place the carbonaceous material in an impregnation tank, immerse it in liquid thermosetting resin under reduced pressure, then switch the system to a pressurized state and heat treat it at a temperature of 30°C or higher until the liquid resin initially hardens. A method for producing an impermeable carbon material characterized by: