On-line decoloring method for epoxy resin

Abstract

The invention belongs to the technical field of epoxy resin, and particularly relates to an online decoloring method of epoxy resin. The online decoloring method for the epoxy resin comprises the following steps: pumping the epoxy resin into a reaction container, starting a circulating system, adding a decoloring agent in a pulse manner, controlling a treatment end point through a pH-chroma two-parameter feedback regulation system, and detecting pH gt; 6.5, automatically supplementing an acidic dispersing agent, and adjusting the pH value to be 5.2-5.8; the epoxy resin online decoloring method provided by the invention aims at bisphenol A epoxy resin based on a functional phthalocyanine blue composite material, and is suitable for accurate regulation and control of chromaticity of a formed epoxy resin product.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resins, and in particular relates to an online decolorization method for epoxy resins. Background Art

[0002] As an important thermosetting polymer material, bisphenol A epoxy resin is widely used in electronic packaging, composite materials, coatings and other fields. The color index of its cured product directly affects the commercial value and optical performance requirements of the end product, especially in high-end applications such as LED packaging and optical lenses, where the color must be strictly controlled below 10Pt-Co units. However, residual quinone compounds, phenoloxyl radicals and other chromophores in the resin synthesis process, as well as thermal oxidation byproducts produced during the high-temperature curing stage, often cause yellowing of the finished product (color value of 20-50Pt-Co units).

[0003] The prior art has the following defects in the decolorization of epoxy resin: (1) Traditional organic dye decolorization method: The mechanism of action of traditional organic decolorizers, represented by methylene blue, relies on adsorption or oxidation reactions between molecules, but they have dual defects in practical applications. On the one hand, there is a natural threshold for decolorization efficiency, which can only reduce the color of the solution by 3-5 Pt-Co units; on the other hand, the molecular structure stability of this type of substance leads to a prominent residual risk, and the unadsorbed decolorizer molecules are prone to form secondary coloring sources in the treated material.

[0004] (2) Inorganic adsorbent method: Although inorganic adsorbent materials such as silica gel and molecular sieves have a large specific surface area, their surface active sites have an essential defect in the recognition ability of quinone chromophores. It is necessary to add ≥5wt% of adsorbent to achieve a basic decolorization effect. Excessive addition not only increases material costs, but also reduces the transparency of the resin product due to the optical scattering effect of the adsorbent particles.

[0005] (3) Chelating agent method: Chelating agents such as EDTA remove metal ion-type color-forming substances through coordination bonding. The boundary of action is clearly limited to ionic pollutants. For example, for organic chromophores such as azo and anthraquinone, the coordination mechanism of the chelating agent cannot form an effective effect.

[0006] (4) Process limitations: The current decolorization process generally has the inherent defect of process interruption. Whether it is the solid-liquid separation link of the adsorption method or the long-term reaction residence of the chemical oxidation method, the material needs to be separated and processed from the main production line. For large-tonnage storage tank systems, this offline processing mode not only causes the production rhythm to stagnate, but also fails to respond to water quality fluctuations in real time. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide an online decolorization method for epoxy resin, which is suitable for precise control of the chromaticity of formed epoxy resin products for bisphenol A type epoxy resin based on functionalized phthalocyanine blue composite materials.

[0008] The epoxy resin online decolorization method of the present invention comprises the following steps: pumping the epoxy resin into a reaction container, starting a circulation system, adding a decolorizing agent by a segmented gradient injection process, controlling the treatment end point by a pH-chromaticity dual parameter feedback adjustment system, automatically adding an acidic dispersant when the pH value is greater than 6.5, and adjusting the pH value to between 5.2 and 5.8; The decolorizing agent is made of the following substances in parts by weight: 80-90 parts of phthalocyanine blue derivatives, 5-10 parts of dispersants, 2-5 parts of stabilizers, 1-3 parts of synergists, and 50-100 parts of aromatic hydrocarbon solvents.

[0009] The decolorizing agent is added by a segmented gradient injection process. In the first stage, 60-70% of the total decolorizing agent is injected, and in the second stage, the remaining decolorizing agent is injected in a pulsed manner.

[0010] The mathematical model of decolorizing agent injection amount is: m=(V×ρ×(C0-C t )) / (K×ε×10 4 ), in: m-mass of decolorizing agent kg; V-Epoxy resin volume m 3 ; ρ-resin density g / cm³; C0 / C t - Initial chromaticity / target chromaticity; K-phthalocyanine blue adsorption capacity constant 0.45; ε-Equipment efficiency factor 0.95.

[0011] The preparation process of the decolorizing agent is as follows: taking a phthalocyanine blue derivative, adding a dispersant, a stabilizer and a synergist, and ball-milling the mixture together, dispersing the mixture in an aromatic hydrocarbon solvent, and ultrasonically obtaining the decolorizing agent.

[0012] The phthalocyanine blue derivative is sulfonate copper phthalocyanine and amino zinc phthalocyanine, and the mass ratio thereof is (12-15):1.

[0013] The dispersant is polyethylene glycol-b-polystyrene block copolymer, and its number average molecular weight Mn is 3000-8000, preferably 5000; the stabilizer is magnesium stearate, and the synergist is beta-cyclodextrin.

[0014] The ball milling speed is 250-350 rpm, and the ball milling time is 1.5-2.5 h.

[0015] The ultrasonic power is 450-550W, the frequency is 25-30kHz, and the ultrasonic time is 25-35min.

[0016] Start the circulation system and maintain the epoxy resin flow rate at 10-30m 3 / h, and the temperature rises to 53-57℃.

[0017] The acidic dispersant is isopropyl citrate, and the aromatic hydrocarbon solvent is preferably toluene.

[0018] The present invention selects phthalocyanine blue derivatives with specific substituents (such as sulfonic acid phthalocyanine copper and aminophthalocyanine zinc) to capture the quinone structure in the resin (binding energy ΔG=-28.6kJ / mol) through intermolecular π-π stacking; innovatively adopts a quaternary composite system of phthalocyanine blue derivatives, polyethylene glycol-b-polystyrene block copolymer, magnesium stearate, and β-cyclodextrin. The sulfonic acid group of the phthalocyanine blue derivative provides electrostatic repulsion to prevent phthalocyanine blue from self-aggregating, and the amino group enhances the charge transfer complexation with the quinone structure and β-cyclodextrin coating to achieve a sustained release function. The present invention preferably adds a decolorant in two stages, first adding most of the decolorant to quickly adsorb free chromophores to improve efficiency, and in the second stage, using an established mathematical model to supplement the decolorant, preserve color, and remove newly oxidized color-forming substances.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The epoxy resin online decolorization method of the present invention uses a sulfonic acid group / amino group disubstituted phthalocyanine blue composite material as a decolorizing agent, which can accurately control the color of the formed epoxy resin product.

[0020] (2) The online decolorization method of epoxy resin of the present invention establishes a mathematical model of decolorizer feeding, combines the two-stage treatment of "main decolorization + color preservation", accurately and efficiently controls the regulation of chromaticity, and has a good decolorization effect.

[0021] (3) The epoxy resin online decolorization method of the present invention adopts a chromaticity-pH value linkage control algorithm to adjust to the optimal adsorption pH, which is automatic and efficient. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with specific embodiments.

[0023] Specifically, the preparation process of the decolorizing agent is as follows: take sulfonate copper phthalocyanine and amino phthalocyanine zinc (80-90 parts) in a mass ratio of (12-15):1, add 5-10 parts of polyethylene glycol-b-polystyrene block copolymer (Mn3000-8000), 2-5 parts of magnesium stearate, and 1-3 parts of β-cyclodextrin, ball mill at 250-350rpm for 1.5-2.5h, disperse in 50-100 parts of toluene and ultrasonicate, the ultrasonic power is 450-550W, the frequency is 25-30kHz, and the ultrasonic time is 25-35min to obtain a decolorizing agent.

[0024] Specifically, the epoxy resin online decolorization method is as follows: the epoxy resin is pumped into a jacketed reactor, the circulation system is turned on, and the epoxy resin is kept for 10-30 minutes. 3 / h, the temperature is raised to 53-57℃, and the decolorant is added by segmented gradient injection process. The treatment end point is controlled by the pH-chromaticity dual parameter feedback adjustment system. When the pH of the decolorization system is detected to be >6.5, the acidic dispersant isopropyl citrate is automatically added to adjust the pH to the optimal adsorption range of 5.2-5.8. In the process of adding the decolorant, the optimal two-stage addition is adopted, and 60-70% of the total amount of the decolorant is injected first to achieve fast and efficient decolorization, and the remaining decolorant is injected in pulses until the system pH is >6.5.

[0025] The mathematical model of the amount of decolorizing agent added is: m=(V×ρ×(C0-C t )) / (K×ε×10 4 ), in: m-mass of decolorizing agent kg; V-Epoxy resin volume m 3 ; ρ-resin density g / cm³; C0 / C t - Initial chromaticity / target chromaticity; K-phthalocyanine blue adsorption capacity constant 0.45; ε-Equipment efficiency factor 0.95.

[0026] The chromaticity described in the present invention refers to the Pt-Co chromaticity.

[0027] Sulfonate copper phthalocyanine (Xi'an Qiyue Biotechnology Co., Ltd.); Aminophthalocyanine zinc (Shanghai Aladdin Biochemical Technology Co., Ltd.); Polyethylene glycol-b-polystyrene block copolymer, number average molecular weight 3000 / 5000 / 8000 (Xi'an Qiyue Biotechnology Co., Ltd.); Magnesium stearate (Gaomi Xinwei Auxiliary Agent Co., Ltd.); β-Cyclodextrin (Shanghai Tongyuan Chemical Co., Ltd.); DF128 resin: density 1.17g / cm 3 , Pt-Co chromaticity 18 (Dongfang Feiyuan (Shandong) Electronic Materials Co., Ltd.); DF127 resin: density 1.16g / cm 3 , Pt-Co chromaticity 19.5 (Dongfang Feiyuan (Shandong) Electronic Materials Co., Ltd.); DF6101 resin: density 1.18g / cm 3 , Pt-Co chromaticity 17 (Dongfang Feiyuan (Shandong) Electronic Materials Co., Ltd.).

[0028] Example 1 The preparation process of the decolorizing agent is as follows: take 42g of sulfonate copper phthalocyanine and 3g of aminophthalocyanine zinc, add 5g of polyethylene glycol-b-polystyrene block copolymer (Mn5000), 2g of magnesium stearate, and 1.5g of β-cyclodextrin, ball mill at 300rpm for 2h, disperse in 30g of toluene and ultrasonicate, the ultrasonic power is 500W, the frequency is 28kHz, and the ultrasonic time is 30min to obtain the decolorizing agent.

[0029] Example 2 The preparation process of the decolorizing agent is as follows: take 44.2g of sulfonate copper phthalocyanine and 3.6g of aminophthalocyanine zinc, add 3.8g of polyethylene glycol-b-polystyrene block copolymer (Mn3000), 1.1g of magnesium stearate, and 0.8g of β-cyclodextrin, ball mill at 250rpm for 2.5h, disperse in 40g of toluene and ultrasonically control the ultrasonic power to 450W, the frequency to 25kHz, and the ultrasonic time to 35min to obtain the decolorizing agent.

[0030] Example 3 The preparation process of the decolorizing agent is as follows: take 44g of sulfonate copper phthalocyanine and 3g of aminophthalocyanine zinc, add 2.7g of polyethylene glycol-b-polystyrene block copolymer (Mn8000), 2.6g of magnesium stearate, and 1.2g of β-cyclodextrin, ball mill at 350rpm for 1.5h, disperse in 50g of toluene and perform ultrasound with an ultrasonic power of 550W, a frequency of 30kHz, and an ultrasonic time of 25min to obtain a decolorizing agent.

[0031] Example 4 This example uses the decolorizing agent prepared in Example 1.

[0032] The epoxy resin online decolorization method: 35m 3 DF128 resin is pumped into the jacketed reactor, and the circulation system is turned on for 20 minutes. 3 / h, raise the temperature to 55℃, plan to reduce the chromaticity from 18 to 10, calculate the total amount of decolorant added to be 76.6g through mathematical model, inject the decolorant through metering pump in gradient mode: first stage: first add 60% of the total decolorant, and in the second stage, inject the remaining 40% decolorant in pulse mode, and control the treatment end point through pH-chromaticity dual parameter feedback adjustment system. When it is detected that the pH of the decolorization system is greater than 6.5, start automatic addition of acidic dispersant isopropyl citrate, adjust the pH to 5.2 to obtain a low-color resin product.

[0033] Example 5 This example uses the decolorizing agent prepared in Example 2.

[0034] The epoxy resin online decolorization method: 30m 3 DF127 resin is pumped into the jacketed reactor, and the circulation system is turned on for 10 minutes. 3 / h, raise the temperature to 57℃, plan to reduce the chromaticity from 19.5 to 10, calculate the total amount of decolorant added to be 77.3g through mathematical model, inject the decolorant through metering pump in gradient mode: first stage: first add 70% of the total amount of decolorant, and in the second stage, inject the remaining 30% in pulse mode, and control the treatment end point through pH-chromaticity dual parameter feedback adjustment system. When it is detected that the pH of the decolorization system is greater than 6.5, start the automatic addition of acidic dispersant isopropyl citrate, and adjust the pH to 5.5 to obtain a low-color resin product.

[0035] Example 6 This example uses the decolorizing agent prepared in Example 3.

[0036] The epoxy resin online decolorization method: 50m 3 DF6101 resin is pumped into the jacketed reactor, and the circulation system is turned on for 30 minutes. 3 / h, raise the temperature to 53℃, plan to reduce the chromaticity from 17 to 10, calculate the total amount of decolorant added to be 96.6g through mathematical model, inject the decolorant through metering pump in gradient mode: first stage: first add 65% of the total decolorant, and in the second stage, inject the remaining 35% in pulse mode, and control the treatment end point through pH-chromaticity dual parameter feedback adjustment system. When it is detected that the pH of the decolorization system is greater than 6.5, start automatic addition of acidic dispersant isopropyl citrate, adjust the pH to 5.8 to obtain low-color resin products.

[0037] Comparative Example 1 This comparative example adopts activated carbon decolorization, and the decolorization method of the epoxy resin is: 35m 3 DF128 resin is pumped into the jacketed reactor, and the circulation system is turned on for 20 minutes. 3 / h, raise the temperature to 55°C, add 10kg of activated carbon, stir and treat for 8h, and filter through a filter to obtain the activated carbon decolorized epoxy resin.

[0038] Comparative Example 2 This comparative example is consistent with Example 4, except that the decolorizing agent is changed to methylene blue to obtain an epoxy resin decolorized by methylene blue.

[0039] The epoxy resins before decolorization and the epoxy resins after decolorization in the above examples and comparative examples were compared, and the treatment time of the comparative examples and the examples was also compared. The results are shown in Table 1.

[0040] Table 1 Test results

[0041] It can be seen from the above that the chromaticity of the epoxy resin decolorized by the present invention is reduced by more than 50%, and the processing efficiency can be increased by up to 4 times. Compared with the traditional decolorization method, the present invention has the advantage of efficiently and quickly reducing the chromaticity of the resin.

[0042] The resins decolorized in the above Examples 4-6 and Comparative Examples 1-2 were subjected to an aging test at 85°C / 500h, and the chromaticity was tested, and the results are shown in Table 2. As can be seen from Table 2, the chromaticity of the epoxy resin after decolorization of the present invention only increased by less than 1.2 units, which is significantly better than the industry standard (allowable increase of ≤3 units).

[0043] Table 2 Aging test results

Claims

1. An online decolorization method for epoxy resin, characterized in that: Pump the epoxy resin into the reaction vessel, start the circulation system, add the decolorant by using the segmented gradient injection process, control the treatment end point by the pH-color dual parameter feedback adjustment system, automatically add the acidic dispersant when the pH is detected to be >6.5, and adjust the pH to between 5.2-5.8; The decolorizing agent is made of the following substances: 80-90 parts of phthalocyanine blue derivatives, 5-10 parts of dispersants, 2-5 parts of stabilizers, 1-3 parts of synergists, and 50-100 parts of aromatic hydrocarbon solvents.

2. The method for online decolorization of epoxy resin according to claim 1, characterized in that: The specific process of segmented gradient injection is as follows: 60-70% of the total amount of decolorizing agent is injected in the first stage, and the remaining decolorizing agent is injected in a pulsed manner in the second stage.

3. The on-line decolorization method for epoxy resin according to claim 1 or 2, characterized in that: The total injection amount of decolorizing agent is used to establish a mathematical model: m=(V×ρ×(C0-C t )) / (K×ε×10 4 ), in: m-mass of decolorizing agent kg; V-Epoxy resin volume m 3 ; ρ-resin density g / cm³; C0 / C t - Initial chromaticity / target chromaticity; K-phthalocyanine blue adsorption capacity constant 0.45; ε-Equipment efficiency factor 0.

95.

4. The method for online decolorization of epoxy resin according to claim 1, characterized in that: The preparation process of the decolorizing agent is as follows: taking a phthalocyanine blue derivative, adding a dispersant, a stabilizer and a synergist, and ball-milling the mixture together, dispersing the mixture in an aromatic hydrocarbon solvent, and ultrasonically obtaining the decolorizing agent.

5. The on-line decolorization method for epoxy resin according to claim 1 or 4, characterized in that: The phthalocyanine blue derivative is sulfonate copper phthalocyanine and amino zinc phthalocyanine, and the mass ratio thereof is (12-15):

1.

6. The on-line decolorization method of epoxy resin according to claim 5, characterized in that: The dispersant is polyethylene glycol-b-polystyrene block copolymer, and the number average molecular weight Mn thereof is 3000-8000; the stabilizer is magnesium stearate, and the synergist is beta-cyclodextrin.

7. The on-line decolorization method for epoxy resin according to claim 4, characterized in that: The ball milling speed is 250-350 rpm, and the ball milling time is 1.5-2.5 h.

8. The method for online decolorization of epoxy resin according to claim 7, characterized in that: The ultrasonic power is 450-550W, the frequency is 25-30kHz, and the ultrasonic time is 25-35min.

9. The method for online decolorization of epoxy resin according to claim 1, characterized in that: Start the circulation system and maintain the epoxy resin flow rate at 10-30m 3 / h, and the temperature rises to 53-57℃.

10. The on-line decolorization method for epoxy resin according to claim 1 or 4, characterized in that: The acidic dispersant is isopropyl citrate, and the aromatic hydrocarbon solvent is toluene.

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