E-44 epoxy resin purification technology and experimental data

Yu Wendong, Duan Wuhua, Zhang Chengqun, Zhou Xiuzhu, Zhou Jiazhen

(Nuclear Energy Technology Design Institute, Tsinghua University, Beijing 100084)

Abstract: The viscosity and density of E-44 epoxy resin adhesives at different temperatures were measured. The effect of the volume ratio of E-44 epoxy resin and benzene on phase entrainment was investigated with a φ50 mm centrifugal extractor, and the effect of various operating conditions (rotational speed, flow ratio, and total flow rate) on the purification effect was investigated. Φ230mm centrifugal extractor was used for industrial scale field test. The test results showed that the content of inorganic chlorine in E-44 epoxy resin after purification was less than 5mgPL when benzene solvent was added. When the benzene solvent is not added, the content of inorganic chlorine in the E-44 epoxy resin gel after purification is less than 100 mg PL.

Keywords: epoxy resin glue; high viscosity; purification; centrifugal extractor

Epoxy resin is a kind of high molecular polymer with excellent corrosion resistance, electrical insulation, adhesion and high mechanical strength. It is widely used in anti-corrosion anti-rust coating, electrical insulation, electronic seals, adhesives, Glass steel products and construction materials and other industrial fields. In the process of synthesizing epoxy resin, the generated inorganic chlorine and other impurities will seriously affect its electrical insulation performance, and the synthetic epoxy resin glue needs to be purified. The density and viscosity of the synthesized epoxy resin adhesive are relatively large. Generally, the viscosity and density of the epoxy resin adhesive are reduced by adding an inert solvent, so as to enhance the uniform contact between the epoxy resin adhesive and water, thereby favoring inorganic materials. Removal of impurities such as chlorine. At present, domestic manufacturers use imported equipment more frequently and are expensive.

It is necessary to develop a process that uses domestic equipment to purify the epoxy resin glue. Compared to the washing and purifying equipment that uses gravity to complete the mixing and separation of the two phases, the centrifugal extractor relies on centrifugal force to complete the mixing and separation of the two phases, which greatly enhances the mixing of the two phases and promotes mass transfer. 2], is conducive to the purification of epoxy resin glue. For this purpose, first of all, a self-developed centrifugal extractor was used to conduct an experimental study on the purification process of E-44 epoxy resin glue added with benzene solvent. Satisfactory results.

The use of inert solvents to reduce the viscosity and density of the epoxy resin glue is beneficial to the purification of high-viscosity epoxy resin glues. Inevitably large amounts of inert solvents are consumed, and the discharged sewage also causes serious pollution to the environment. For this reason, on the basis of the experimental research on the purification process of E-44 epoxy resin glue solution with the addition of benzene solvent, a centrifugal extractor was used to study the purification process of E-44 epoxy resin glue solution without benzene solvent.

1 test section

111 test equipment

The main equipment used in the test is a self-developed ring-gap centrifugal extractor, the structure of which is shown in Figure 1.

Fig.1 Structure of ring-gap centrifugal extractor

1----Axis; 2----Heavy phase crucible; 3----Light phase crucible;

4----heavy phase export; 5--heavy-phase collection chamber;

6----Light phase collection chamber; 7----Light phase export;

8----Radial blades; 9----Mixed phase inlet;

10----Drum; 11----shell; 12----Heavy-phase import;

13----Light phase import; 14---- gap;

15---- ring gap; 16---- fixed blade

It is mainly composed of shafts, rotors and housings [3 to 5].

The drum includes a sag section and a clarification section. On the squat section there are a heavy phase 堰 and a light phase 控制 that control the overflow radii of the two phases; the fining section is equipped with radial vanes. The upper part of the shell has two separate collection chambers and outlet tubes. The lower part of the shell has two-phase inlets and the bottom is equipped with fixed vanes. The space between the inner wall of the housing and the outer wall of the drum is called an annulus. The mixing and mass transfer of the two-phase fluid takes place in the annulus.

When the two-phase liquids with different density and incompatible with each other enter the annulus from the two feed inlets respectively, relying on the rotation of the rotating drum and the friction between the liquid layers, a vigorous and uniform mixing in the annulus is achieved. The mass transfer process is thus accelerated.

When the high-speed rotating mixture flows down to the fixed blade, it enters the drum from the mixed phase port at the bottom of the drum. The mixed liquid is phase separated by centrifugal force, and the heavy phase is thrown to the outer edge of the drum, and is collected outside the drum wall. After passing through the vertical tunnel near the drum wall, the heavy phase flows into the heavy phase collection chamber and flows out from the heavy phase outlet. The light phase is squeezed towards the inside of the drum and flows into the light phase collection chamber via the light phase and horizontal channels and exits the light phase outlet.

Centrifugal extractors can be used to purify high-viscosity glues if they have a large separation factor.

For a φ230 mm centrifugal extractor, the separation factor is 514 when the rotational speed is 2000 rPmin. Due to the large separation factor, the phase separation time can be greatly shortened, and conditions can be created to enhance mixing and promote mass transfer.

112 test methods

Measurement of Viscosity and Density of 11211 E-44 Epoxy Resin Adhesive

The temperature has a great influence on the viscosity and density of E-44 epoxy resin glue. Therefore, the viscometer and pycnometer were used to determine the viscosity and density of E-44 epoxy resin glue at different temperatures. The appropriate operating temperature. Effect of Temperature and Flow Ratio on System Emulsification E-44 epoxy resin-benzene glue solution and water at different temperatures were added to the separation funnel at a certain flow ratio, shaken for 5 minutes, and allowed to stand for stratification to observe emulsification. The test stipulates that the phase separation time is less than 3 minutes for non-emulsification, otherwise it is emulsified.

First, the non-emulsified zone obtained by the separatory funnel test was verified with a φ50mm centrifugal extractor. The rotational speed of the centrifugal extractor was 3000 rPmin. The test procedure is shown in Figure 2. Then, the effect of the volume ratio of E-44 epoxy resin and benzene on phase entrainment, and the rotational speed, flow ratio, and total flow rate were systematically studied.

The effect of conditions on the washing effect.

1) E-44 epoxy resin glue solution with benzene solvent added: The φ230mm centrifugal extractor was directly used for industrial scale testing. The test flow is the same as in Fig. 2.

Figure 2 Test flowchart

1----Centrifugal extractor; 2----Flowmeter;

3----Heavy-phase high position tank; 4----Light-phase high position tank;

5----Valve; 6----Heavy phase storage tank;

7----Light phase storage tank

2) E-44 Epoxy resin glue solution without benzene solvent purification: The synthetic E-44 epoxy resin glue solution has a large viscosity, the pipeline transportation is difficult, and salt blocks in the glue solution are not easily removed. Therefore, The following measures were taken during the purification test of the E-44 epoxy resin glue solution without benzene solvent: hot water of about 90°C was added to the E-44 epoxy resin glue solution, and the temperature of the mixed solution was About 80 °C. At temperatures around 80°C, the E-44 epoxy resin has a viscosity of less than 012 Pa·s and good fluidity. The test flow is shown in Figure 3.

Figure 3 test flow chart

1----Centrifugal extractor; 2----Stirring pot;

3----Valve 4----Heavy-phase storage tank;

5----Light phase storage tank

2 test results and discussion

211 Viscosity and Density at Different Temperatures The measured values ​​of the viscosity and density of E-44 epoxy resin at different temperatures are shown in Table 1 (omitted).

The test results show that, at lower temperatures, the viscosity and density of the E-44 epoxy resin adhesive are large, and the temperature increases, the viscosity and density of the E-44 epoxy resin adhesive are both decreased, when the temperature is 80 °C The viscosity of the E-44 epoxy resin adhesive is 01109 Pa·s. At this time, the fluidity is good.

212 Temperature and flow ratio effects on two-phase emulsification

E-44 Epoxy Resin - The system consisting of a benzene glue liquid and water is prone to emulsification, causing phase separation difficulties. Therefore, an operable area must be found. The test results show that the degree of two-phase emulsification is related to the flow ratio and temperature, and the higher the temperature, the larger the allowable flow ratio of the operable flow. When the temperature is 35°C to 55°C,

The flow ratio (QaPQo) of the two-phase non-emulsifiable operable zone was 1P10 to 1P7 (35C) and 1P1 to 10P1 (55C).

213φ50mm centrifugal extractor test

Entrainment effects

The density and viscosity of the synthesized E-44 epoxy resin glue are relatively large. At 25°C, the measured density is 11167gPcm3, and the viscosity is 91100Pa·s. The addition of benzene can reduce its density and viscosity. The degree of reduction depends on E-. 44 Volume ratio of epoxy resin to benzene. The φ50mm centrifugal extractor was used to test the influence of the volume ratio of E-44 epoxy resin to benzene on phase entrainment. The test results are shown in Table 2 (omitted).

The test results show that the more benzene is added, the lower the density of the E-44 epoxy resin-benign glue solution, the lower the viscosity, and the lower the entrainment amount, when the volume ratio of E-44 epoxy resin to benzene is lower than 1P4. The amount of phase entrainment is <015%. Therefore, adding benzene is beneficial to the purification of E-44 epoxy resin glue.

21312 Effect of various operating conditions on washing effect

The operating conditions such as rotation speed, total flow and flow ratio have an effect on the purification effect. The test results are shown in Table 3 (omitted). The content of inorganic chlorine in the raw material liquid is 11272 gPL.

The above results indicate that increasing the rotational speed can enhance the mixing of the two-phase liquid in the annulus within a certain range, so that the purification effect can be improved. However, when the rotational speed is too high, the two-phase liquid is easy to emulsify, which increases the phase separation difficulty and causes the phase. Entrainment is not conducive to purification, so it is necessary to find the best speed. For centrifugal extractors of different sizes, the best speed is not the same. It needs to be determined by tests. The larger the flow rate than QaPQo, the smaller the total flow and the better the purification effect.

214 φ230mm centrifugal extractor industrial scale test

21411 E-44 with benzene solvent added

The purification of the epoxy resin glue liquid was based on the φ50mm centrifugal extractor test, and the best test conditions were selected. An industrial scale test was carried out using 6 batches of feed solution using a φ230mm centrifugal extractor. The content of inorganic chlorine in the test raw material liquid is 11272g PL, the test temperature is 40°C-50°C, the total flow rate is 215m3Ph, the volume ratio of E-44 epoxy resin glue to benzene is 1P3, and the flow ratio (QaPQo) is 115P1, heavy phase helium diameter 118mm, speed 2000rPmin. The potential electrode method was used to analyze the content of inorganic chlorine in E-44 epoxy resin-benign glue solution after washing. The test results showed that the content of inorganic chlorine in the E-44 epoxy resin-benign glue solution after washing was less than 5 mg PL, which met the electrical quality standards.

21412 Purification of E-44 Epoxy Resin Epoxy without Benzene Solvent

An industrial scale test was performed using a φ230 mm centrifugal extractor. The content of inorganic chlorine in the raw material solution was 11272 g PL, the temperature was 40° C. to 50° C., and the temperature after mixing with the hot water of 90° C. was about 80° C. The test results are shown in Table 4 (abbreviated).

The above test results show that after washing with water, the content of inorganic chlorine in E-44 epoxy resin is less than 100 mg PL, which has reached the quality standard of the department. Using this production technology, the environmental pollution caused by toxic organic solvents is reduced, and the economic benefits are improved because no organic solvents are added for washing.

3 Conclusion

It is feasible to use φ230mm centrifugal extractor to purify E-44 epoxy resin glue. When benzene solvent is added for purification, under the appropriate operating conditions, the content of inorganic chlorine in E-44 epoxy resin is less than 5mgPL after purification. , To achieve the electrical quality standards, when not added to the purification of benzene solvent, after washing at 80 °C, the content of inorganic chlorine in E-44 epoxy resin is less than 100mgPL, has reached the quality standards of the Ministry of excellent quality, and, greatly Reduced environmental pollution. The entire production process is easy to operate, can be continuously operated, and the equipment is compact, occupying a small area of ​​the factory, and easy to implement automatic control.