JPS6352666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for concentrating a thermosetting resin, and in particular, to prevent solidification or deterioration of the concentrated resin due to abnormal reactions, and to obtain a stable product resin continuously for a long period of time. The present invention relates to a method for concentrating thermosetting resins that makes it possible to do so. Thermosetting resins such as phenolic resins are
Because of its many excellent features, it has been produced in larger quantities than ever before, and its demand is likely to continue to increase. These resins contain impurities such as suspending agents (mainly water is used) and unreacted monomers at the end of the polymerization reaction, and cannot be used as product resins as they are, so a process to remove the impurities is required. . In general, many thermosetting resins have an extremely fast reaction rate, and particularly in the final step of removing impurities, they tend to cause abnormal reactions, resulting in solidification or deterioration. For this reason, the conventional technology mainly uses a batch-type evaporator to evaporate and concentrate the impurities at an extremely slow rate.
It has drawbacks such as long processing time, difficulty in changing resin types, and post-processing such as cleaning the inside of the can at the end of concentration, which requires a great deal of labor and time. An object of the present invention is to provide a method for concentrating a thermosetting resin, which eliminates the above-mentioned drawbacks and makes it possible to obtain a stable product resin while ensuring a high evaporation concentration rate. Therefore, the main point of the present invention is to perform evaporative concentration by combining a thin film evaporator having a drafting blade and a dedicated diluent inlet as a concentrating device with a concentrate extraction pump having a jacket for cooling the concentrate. The advantage is that it is possible to control the diluent injection amount, resin temperature, etc. according to the type or property of the resin and the progress state of the reaction. Embodiments of the present invention will be described below with reference to the drawings.
Common parts in each drawing are given the same reference numerals. FIG. 1 shows an embodiment of the evaporation concentration apparatus used in the present invention. The configuration and operation of the thin film evaporator 11 and extraction pump 20 will be explained with reference to this drawing. Reference numeral 40 denotes a cylindrical heat transfer shell, inside which a rotating shaft 1 has rotary blades 2 and scraping blades 10.
The rotating shaft 1 is supported by an upper bearing 42 and a lower bearing 4 so that a gap 41 between the heat transfer shell 40 and casing 45 and the rotary blade 2 and the scraping blade 10 is maintained at an appropriate value. It is configured so that it can be rotated by a motor (not shown) via a drive pulley 43. A heating jacket 3 having a heating medium inlet 8 and a heating medium outlet 9 is provided outside the heat transfer cylinder 40, and is heated by the heating medium. Further, the heat transfer cylinder 40 is provided with a diluent inlet 44 at an appropriate portion below the upper and lower halves. At the bottom of the thin film evaporator 11 , a casing 45,
A withdrawal pump 20 with a concentrate refrigerant inlet 21, a concentrate refrigerant outlet 22 and a refrigerant jacket 23
are mounted as close as possible. The raw material to be evaporated and concentrated is continuously injected into the thin film evaporator 11 from the raw material inlet 5, and is formed into a thin film by the action of the rotating rotor blades 2.
1 downwards. Since the heat transfer shell 40 is heated by the heating jacket 3, the evaporated components in the raw material evaporate, become a concentrate, move downward through the gap 41 by the action of the scraping blades 10, and are transferred to the extraction pump 20. It is pushed in and is pulled out from the concentrate outlet 6 by its action. On the other hand, the evaporated gas moves upward in the space of the heat transfer cylinder 40 and is extracted from the evaporated gas outlet 7. A diluent is continuously or intermittently injected from the diluent inlet 44 to prevent abnormal reactions of the concentrate or to adjust the viscosity. A part of the diluent is evaporated and combined with the evaporated gas by the above-mentioned evaporation effect, and the rest is combined with the concentrate. Concentrate refrigerant is continuously or intermittently injected into the refrigerant jacket 23 to prevent abnormal reactions due to a rise in the temperature of the concentrate and to maintain the temperature at a constant level before drawing it out. By the above-mentioned action, the thermosetting resin raw material can be evaporated and concentrated to obtain a product resin. In general, thermosetting resins rapidly cause problems such as abnormal reactions at the end of the process of removing impurities, so if there is a slight abnormality that occurs, a diluent is immediately injected to prevent it. It is also effective to extract the liquid as soon as possible and at the lowest possible temperature as long as it maintains fluidity after the concentration is completed. Thin film evaporator 11 and extraction pump 2 according to the invention
By using an evaporation concentration device combining 0, the above requirements can be achieved because a diluent is used and a refrigerant jacket is provided, and thermosetting resin raw materials can be efficiently concentrated to obtain stable product resin. It is possible. Hereinafter, a concentration method using the evaporation concentration apparatus shown in FIG. 1 will be explained. Example 1 FIG. 2 shows an example of the present invention. The raw material 31 is continuously injected into the thin film evaporator 11 , where the components to be evaporated are evaporated and concentrated, and then the extracting pump 20
and extracted as a concentrate 35. Evaporated gas 36 is cooled by condensate refrigerant 38 in cooler 3
7 and is extracted as a condensate 39. The diluent 34 is injected into the lower part of the thin film evaporator 11 to prevent abnormal reactions of the concentrate 35 or to adjust the viscosity. A part of the diluent 34 is combined with the evaporated gas 36 and the rest is combined with the concentrate 35. unite. The concentrate refrigerant 33 is injected into the jacket of the withdrawal pump 20 , serves to prevent abnormal reactions due to temperature rise of the concentrate 35, and to maintain the concentrate at a constant temperature before being discharged. With the above-described configuration and operation, thermosetting resin can be concentrated in a short time, efficiently, at low cost, and in continuous operation without the need to stop and clean the device. Embodiment 2 FIG. 3 shows another embodiment of the present invention. In this embodiment, the temperature of the concentrate 35 is detected by the temperature detector 51, and the injection amount and injection frequency of the diluent 34 and the injection amount and injection frequency of the concentrate refrigerant 33 are controlled according to the temperature. It is characterized by
The rest is the same as in the first embodiment. The injection volume and frequency are controlled by diluent control valve 52 and concentrate refrigerant control valve 53. As a result of experiments, it has been found that the reaction rate of thermosetting resin is greatly influenced by the temperature of the resin, and in order to obtain a stable product resin, it is necessary to control the temperature of the resin at a constant level. Therefore, with this configuration, a stable product resin can be obtained at all times. Embodiment 3 FIG. 4 shows still another embodiment of the present invention. In this embodiment, the viscosity of the concentrate 35 is measured using a viscosity detector 54.
and the injection amount and injection frequency of the diluent 34 and the concentrate refrigerant 33 depending on its viscosity.
This embodiment is characterized by controlling the injection amount and frequency of injection, and other aspects are the same as in Example 1.
The injection amount and injection frequency are controlled by the diluent control valve 52.
and concentrate refrigerant control valve 53. As a result of experiments, it has been found that phenomena such as abnormal reactions in thermosetting resins are most sensitively manifested as changes in viscosity, and if the above-mentioned control is performed in immediate response to changes in viscosity, stable product resins can be obtained. Note that the injection amount and injection frequency of the diluent 34 and the injection amount and injection frequency of the concentrate refrigerant 33 can also be controlled depending on the temperature and viscosity of the concentrate. As described above, according to the present invention, the following effects can be obtained. (1) Compared to conventional technology, impurities in the thermosetting resin can be removed by evaporation efficiently and continuously in a short time, and miscellaneous expenses such as operating costs and personnel costs can be saved. (2) Since the equipment is easy to start and stop, processing can be done as needed, making it economical. (3) Since there is no need to frequently clean the equipment, not only can expenses associated with cleaning work be saved, but there is also less need to enter and exit the hazardous environment due to cleaning, resulting in high safety.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the internal structure of a thin film evaporator and a withdrawal pump used in the present invention, and FIGS. 2, 3, and 4 are system diagrams showing different embodiments of the present invention. 1... Rotating shaft, 2... Rotating blade, 3... Heating jacket, 5... Raw material inlet, 6... Concentrate outlet,
7... Evaporated gas outlet, 10... Scraping blade, 11
... thin film evaporator, 20 ... extraction pump, 23...
... Refrigerant jacket, 37 ... Cooler, 40 ... Heat transfer cylinder, 44 ... Diluent inlet, 51 ... Temperature detector, 52 ... Diluent control valve, 53 ... Concentrate refrigerant control valve, 54 ... ...Viscosity detector.

Claims (1)

[Claims] 1. A thin film evaporator having a raw material inlet, an outlet for evaporated gas generated by heating the raw material, and a diluent inlet, an external heating jacket, and an internal rotary blade and scraping blade. , an evaporative concentrator comprising a concentrate extraction pump having an external concentrate cooling jacket and a concentrate outlet, and a cooler for cooling and condensing the evaporated gas, at least one of the temperature or viscosity of the concentrate at the concentrate outlet; The diluent is continuously or intermittently injected from the diluent inlet depending on the value of , and the concentrate refrigerant is continuously or intermittently injected into the concentrate cooling jacket. Method for concentrating curable resin. 2 The injection amount and injection frequency of the diluent injected into the diluent inlet and the injection amount and injection frequency of the concentrate refrigerant injected into the concentrate cooling jacket are adjusted according to the temperature of the concentrate at the concentrate outlet. A method for concentrating a thermosetting resin according to claim 1, wherein the concentration method is controlled by: 3. The injection amount and injection frequency of the diluent injected into the diluent inlet and the injection amount and injection frequency of the concentrate refrigerant into the concentrate cooling jacket are adjusted according to the viscosity of the concentrate at the concentrate outlet. A method for concentrating a thermosetting resin according to claim 1, wherein the concentration method is controlled by: 4. The injection amount and injection frequency of the diluent injected into the diluent inlet and the injection amount and injection frequency of the concentrate refrigerant into the concentrate cooling jacket are determined based on the temperature and viscosity of the concentrate at the concentrate outlet. A method for concentrating a thermosetting resin according to claim 1, wherein the method is controlled according to the following.