JPH08117707A - Cleaning method for epoxy resin mixer - Google Patents

Abstract

PURPOSE: To safely and efficiently clean an uncured epoxy resin stuck to the inside of an epoxy resin mixer without using chlorofluorocarbon-based and chlorine-based solvents and to prevent a detergent from being left. CONSTITUTION: The inside of a mixer 4 in which an epoxy resin composition is mixed is cleaned by a detergent 8 containing γ-butyrolactone or the like as an essential component and having flash point of not less than >=70 deg.C. The inside of the mixer 4 is cleaned in such a way and thereafter decompressed while heating it. The remaining detergent 8 is vaporized and removed and also the vaporized detergent 11 is desirably recovered by a cooling trap 10. Furthermore, air is introduced into the mixer 4 while continuing decompression and the air in the mixer is replaced and thereby removal of the detergent is completely performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an apparatus for mixing an epoxy resin with a curing agent, an inorganic filler, etc., to wash and remove the uncured epoxy resin (composition) adhering to the inside.
The present invention relates to a cleaning method for an epoxy resin mixing device.

[0002]

2. Description of the Related Art In the process of manufacturing an epoxy resin (cured product), an epoxy resin composition composed of an epoxy resin and a curing agent, an inorganic filler, an additive, etc. is mixed in a mixing device and taken out, and then, inside the mixing device. It is necessary to wash and remove the uncured epoxy resin (composition) attached to the.

As a solvent for dissolving an epoxy resin, generally, many organic solvents such as alcohols, ethers, esters, acetals and ketones are known.
However, such a solvent has insufficient dissolving power for the epoxy resin to be used as a cleaning agent for the above-mentioned epoxy resin mixing device, and therefore the resin adhered to the inside of the device can be efficiently cleaned in a short time in the process. Is not only difficult,
It was not preferable in terms of heat stability and safety. That is, the melting or mixing temperature of the epoxy resin is usually 60 to 120 ° C.
Therefore, the mixing device is also washed at a temperature within this range, but the above-mentioned organic solvent (acetone, ethanol, etc.)
Was difficult to handle because its boiling point was lower than the melting temperature of the epoxy resin and there was a high risk of explosion during cleaning of the mixing device. In addition, there is a problem that the storage place, storage conditions, specified quantity, etc. are strictly limited by the Fire Service Act, etc., and a sufficient amount of solvent cannot be secured.

On the other hand, 1,1,1-trichloroethane,
Chlorine-based solvents such as trichlorethylene have a high dissolving power for epoxy resin and are nonflammable, so they do not need to be handled as dangerous substances. They have excellent thermal stability and do not decompose or metamorphose, giving them resin properties. It has been conventionally used as a cleaning agent for epoxy resin mixing devices because it has almost no effect and it has a low boiling point and is easily released into the atmosphere.

[0005]

However, with increasing social awareness of environmental problems, there is a movement to regulate the discharge of substances that may damage the global environment into the atmosphere and water systems. , For example, CFC-based solvents (5 types of CFCs: CFC11, CFC12, CFC113, CFC114, CFC1
15) and 1,1,1-trichloroethane as ozone depleting substances, trichlorethylene as groundwater pollutants,
Their use is being severely restricted.

[0006] Under such circumstances, in the industry that uses CFC113 or other chlorofluorocarbon-based solvents and 1,1,1-trichloroethane, trichloroethylene or other chlorinated solvents, even one day as a substitute for these solvents is used. Early appearance is required. The manufacturing and processing industries of epoxy resins are no exception, and safe and efficient epoxy resins that use highly safe solvents with excellent solubility in place of the chlorine-based solvents, etc. There is an urgent need to develop a cleaning method for mixing devices.

[0007]

Means and Actions for Solving the Problems The inventors of the present invention have been conventionally used as a cleaning agent for an epoxy resin mixing apparatus.
As a result of extensive research on cleaning agents that replace chlorine-based solvents such as CFC113 or 1,1,1-trichloroethane, γ-
The present inventors have found that a solvent containing butyrolactone as an essential component exhibits extremely high resin detergency, and completed the present invention.

That is, the present invention is characterized in that the inside of a mixing apparatus in which an epoxy resin composition is mixed is washed with a detergent containing γ-butyrolactone as an essential component and having a flash point of 70 ° C. or higher. It is a method of cleaning a resin mixing device.

In the cleaning method of the present invention, γ-butyrolactone used as an essential component of a cleaning agent is a liquid having a high boiling point and soluble in water and an organic solvent such as ethanol or ether, and has excellent heat stability. Therefore, even if it is used at the epoxy resin mixing temperature (60 to 120 ° C), decomposition or transformation does not occur. It also has excellent solubility in epoxy resin and dissolves about 5 times the amount of epoxy resin when heated. Therefore, γ-butyrolactone can obtain a sufficient cleaning effect even when mixed with another solvent, but from the viewpoint of the dissolving power and the cleaning speed, the content of γ-butyrolactone should be 25% by weight or more of the entire cleaning agent. Is preferred.

Further, to the detergent used in the present invention, various stabilizers or additives can be added in order to improve the stability with respect to the resin, maintain the stability of the liquid, or improve the dissolving power. . Such stabilizers include hydrocarbons, alcohols, ethers, esters, acetals, ketones, fatty acids, nitroalkanes, amines, amides, glycols, aminoacetals,
Examples thereof include benzotriazoles, but from the viewpoint of thermal stability and safety, dangerous substances such as esters, acetals, and glycols having a high flash point and a high boiling point, Class 4 Class 3
It is desirable to use a solvent that belongs to petroleum. Also,
The blending amount of each of these solvent components is adjusted so that the flash point of the entire solvent is 70
Adjust the temperature above ℃ so that the cleaning agent does not catch fire and explode during cleaning.

The cleaning agent obtained by blending such components has a high flash point and a high boiling point, is less released into the atmosphere, is safe and has excellent thermal stability. On the other hand, it remains in the mixing device after cleaning. It is easy to do so and may be mixed in the composition to be mixed next. Therefore, in the present invention, after cleaning with the cleaning agent, while heating the inside of the mixing device to 80 to 120 ° C., it is more preferably 10 mmHg (T0rr) or less by vacuuming.
The pressure is reduced to 1 Torr or less, and the remaining cleaning agent is evaporated and removed. Further, at this time, in order to completely remove the cleaning agent and dry the inside of the mixing device, it is desirable to forcibly introduce air into the mixing device while continuing evacuation to replace the air in the device. Furthermore, it is desirable that the cleaning agent that has been vaporized by evaporation under reduced pressure can be recovered in the cooling trap and reused without being released to the atmosphere. Furthermore, since the cleaning agent used in the present invention is highly biodegradable, even if it is released into the atmosphere, there is no risk of environmental damage such as ozone layer depletion or water pollution.

By carrying out the method of the present invention having such a structure, the uncured epoxy resin (composition) attached to the inside of the epoxy resin mixing device is treated with a fluorocarbon solvent or
It is possible to wash safely and in a short time without using a chlorine-based solvent such as 1,1,1-trichloroethane or trichlorethylene, and even after washing, no detergent remains in the mixing device. A stable and good quality product can be efficiently manufactured.

[0013]

EXAMPLES Examples of the present invention will be specifically described below.

Example 1 First, an epoxy resin (composition) was prepared in a mixing device. That is, as shown in FIG. 1 (a), an epoxy resin (trade name, manufactured by Ciba-Geigy Co., Ltd.) is placed in a mixing tank 5 (capacity 100 l) of a mixing device 4 having a stirring blade 2 rotated by a motor 1 and a heating jacket 3. CT200) 30Kg and alumina as filler (manufactured by Taiheiyo Random Co., average particle size 20μm)
Epoxy resin 6 was prepared by adding 60 kg and mixing while heating and keeping at 115 ° C. and further adding 9 kg of a curing agent (manufactured by Ciba-Geigy, trade name HT903). Next, as shown in FIG. 1B, the prepared epoxy resin 6 is discharged from the mixing tank 5 through a discharge pipe 7, and then the inside of the mixing tank 5 is shown in Table 1 as shown in FIG. 1C. After being filled with the cleaning agent 8 having the composition, the cleaning agent 8 was stirred by the stirring blade 2 for 15 minutes for cleaning. Also, as a comparative example, it has been used conventionally
Using 1,1,1-trichloroethane as a cleaning agent, the inside of the mixing tank was cleaned in the same manner as in the example.

[0015]

[Table 1] Then, as shown in FIG. 1D, the cleaning liquid 9 is discharged into the discharge pipe 7.
After being discharged from the mixing tank 5 through the
The weight of the whole was measured to measure the weight of the residue, and the appearance inside the mixing tank 5 was visually observed. Table 2 shows the results.

[0016]

[Table 2] In addition, from the epoxy resin 6 previously taken out from the mixing tank 5,
50 g of each sample, which was cooled and solidified, was immersed in each of 800 ml of the cleaning agents shown in Table 1, and the dissolving power of the cleaning agents was examined by measuring the change in weight with time. The measurement results are shown in FIG.

From Table 2, it can be seen that in the mixing tank 5 after cleaning in the examples, almost no residue of epoxy resin adhered is seen, and as in the case of the comparative example cleaned with a chlorine-based solvent,
It can be seen that the uncured epoxy resin remaining in the mixing tank 5 is sufficiently dissolved and washed. Further, it can be seen from the graph of FIG. 2 that the cleaning agent used in the example has a sufficiently large dissolving power exceeding the lower limit of the dissolving power in the actual machine.

Next, as shown in FIG. 1 (e), the cleaning liquid 9
While keeping the temperature inside the mixing tank 5 after discharge at 115 ° C, 0.2
The vacuum was pulled to Torr, and a cooling trap 10 was connected between the mixing tank 5 and a vacuum pump (not shown) to collect the evaporated and vaporized cleaning agent 11. Then, the epoxy resin and alumina were put into the mixing tank 5 again, and the temperature was 115 ° C.
The mixture was mixed while keeping warm, and a curing agent was further added to prepare the next epoxy resin. A curing agent was added to prepare an epoxy resin composition. The gel times of the thus obtained epoxy resins with different amounts of detergent mixed were measured by a gel time tester (YSS No.153, manufactured by Yasuda Seiki Co., Ltd.). The measurement result is shown in FIG. From this graph, it can be seen that the gel time of the epoxy resin is not shortened by the cleaning of the example and the workability is hardly affected.

Example 2 As shown in FIG. 4 (a), the epoxy resin was mixed in the same manner as in Example 1 by using the mixing device 4 in which the air inlet 13 with the valve (leak valve 12) was provided on the upper part of the mixing tank 5. Resin (composition)
6 was prepared, and the obtained epoxy resin 6 was discharged from the mixing tank 5, and then the inside of the mixing tank 5 was heated as shown in FIG.
It was filled with the cleaning agent 8 (γ-butyrolactone 100%) shown in Composition Example 3 and washed with stirring. Next, after discharging the cleaning liquid, the pressure inside the mixing tank 5 was reduced to 0.2 Torr while keeping the temperature inside the heating tank at 115 ° C., the vaporized cleaning agent 11 was collected in the cooling trap 10, and then the leak valve 12 was fully opened. Vacuuming was performed for 5 minutes, and air was introduced into the mixing tank 5 to replace the outside air (FIG. 4 (c)). The residual content of the cleaning agent (γ-butyrolactone) in the mixing tank 5 vacuum-dried in this manner and the residual content of the cleaning agent in the mixing tank 5 before air replacement were measured by gas chromatography. As a result of the measurement, the residual content of the cleaning agent before replacement is 1000 to 600 ppm
On the other hand, after the replacement, it is remarkably reduced to 150 to 50 ppm, and it can be seen that the replacement by introducing the external air is extremely effective for completely removing the cleaning agent.

[0020]

As described above, according to the cleaning method of the present invention, chlorine-based solvents such as 1,1,1-trichloroethane and trichloroethylene whose emission into the atmosphere and water systems is regulated as environmentally destructive substances. Without using the uncured epoxy resin adhered inside the epoxy resin mixing device,
It can be safely and quickly dissolved and washed. Also,
The cleaning agent does not remain in the mixing device even after cleaning, and a stable and good quality product can be efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of a cleaning method for an epoxy resin mixing device of the present invention.

FIG. 2 is a graph showing the results of measuring the dissolving power of the cleaning agent used in the examples of the present invention.

FIG. 3 is a graph showing a result of measuring a change in gel time of an epoxy resin due to mixing of a cleaning agent in an example of the present invention.

FIG. 4 is a diagram schematically showing another embodiment of the cleaning method of the present invention.

[Explanation of symbols]

 2 ... Stirring blade 3 ... Heating jacket 4 ... Mixing device 5 ... Mixing tank 6 ... Epoxy resin 8 ... Cleaning agent 10 ... Cooling trap 12 ... Leak valve 13 ... ...... Air inlet

Claims (4)

[Claims] 1. Cleaning of an epoxy resin mixing device, characterized in that the inside of a mixing device mixed with an epoxy resin is washed with a cleaning agent containing γ-butyrolactone as an essential component and having a flash point of 70 ° C. or higher. Method. 2. The cleaning method for an epoxy resin mixing device according to claim 1, wherein after the cleaning, the inside of the mixing device is heated and decompressed to vaporize and remove the cleaning agent remaining inside. 3. The cooling trap collects the cleaning agent vaporized by depressurization under heating.
A method for cleaning an epoxy resin mixing device as described. 4. The method for cleaning an epoxy resin mixing device according to claim 2, wherein after the cleaning agent remaining in the mixing device is vaporized, air is introduced into the mixing device while continuing to reduce the pressure.