UV-curable polybutadiene insulating resin and continuous flow preparation method

Abstract

The invention relates to the technical field of photocuring materials, in particular to UV-curable polybutadiene insulating resin and a continuous flow preparation method, which comprises the following steps: uniformly mixing double-end carboxyl polybutadiene resin with glycidyl ester or ether with double bonds, introducing the mixed material into a continuous flow reaction kettle, and carrying out a ring-opening esterification reaction, so as to obtain the UV-curable polybutadiene insulating resin. A plurality of layers of plates are arranged in the continuous flow reaction kettle, and each layer of plate is filled with an imidazole catalyst; after the reaction is completed, discharging and cooling to below 60 DEG C, and filtering to obtain the polybutadiene insulating resin; wherein the imidazole catalyst is 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-heptadecyl imidazole or 2-phenylimidazole, and the general formula of the imidazole catalyst is shown in the description. The reaction activity and the crosslinking density of the polybutadiene resin during UV curing are improved. The production efficiency is high, the catalyst can be repeatedly used, the quality of the resin product is high, polybutadiene has excellent insulativity, but the double bond activity of polybutadiene is low, and the modified resin can be used as matrix resin in the UV coating.

Description

Technical Field

[0001] This invention relates to the field of photocurable materials technology, specifically to a UV-curable polybutadiene insulating resin and a continuous flow preparation method. Background Technology

[0002] With the development of science and technology and the rapid growth of the new energy market, insulating materials are indispensable for electrical equipment. Polybutadiene resin, with its excellent electrical insulation and heat resistance, is one of the important insulating materials. As new energy battery cells and their surface treatment materials are constantly being updated, traditional blue films can no longer meet the requirements of fast charging. UV coatings can be fully cured within seconds under UV light at room temperature, while other coatings requiring heat curing will damage the performance of battery cells at temperatures exceeding 100℃. UV coatings have the most promising development prospects in this field, and choosing the right insulating resin is crucial. Polybutadiene itself has excellent electrical insulation properties, but its double bond activity is insufficient. Introducing double bonds through conventional batch reactions generally results in resin quality that is generally low. The reaction temperature needs to be 140-150℃, and the reaction time 3-5 hours. In addition to adding a catalyst, because glycidyl esters or ethers with double bonds are prone to polymerization at 140-150℃, additional polymerization inhibitors are also needed, all of which reduce the quality of the final resin product.

[0003] The Chinese invention patent with application number CN201710608779.9 utilizes the reaction of epoxidized polybutadiene with acrylic acid to improve the activity of double bonds. It uses polybutadiene with epoxy groups to react with a monomer with carboxyl groups. However, acrylic acid is a monomer that is very easy to self-polymerize. The patent uses a traditional high-temperature long-time reaction in a batch reactor, without introducing a polymerization inhibitor or overcoming the impact of acrylic acid self-polymerization on the quality of the final resin. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art where the low double bond activity of traditional polybutadiene resin leads to poor UV curing efficiency, and the low quality and low preparation efficiency of resins with introduced double bonds prepared by ordinary batch reaction.

[0005] To address the above problems, this invention provides a continuous flow preparation method for UV-curable polybutadiene insulating resin, characterized by comprising the following steps:

[0006] S1. The double-ended carboxyl polybutadiene resin and glycidyl ester or ether containing double bonds are mixed evenly using a mixer at a volume ratio of 5.3-19.7:1, wherein:

[0007] The molecular weight Mn of the double-ended carboxyl polybutadiene resin is 1000-5000;

[0008] The glycidyl ester or ether with double bonds is selected from at least one of glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether.

[0009] S2. The mixture is fed into a continuous flow reactor for ring-opening esterification reaction. The continuous flow reactor is equipped with multiple layers of plates, each layer of which is filled with an imidazole catalyst. The reaction temperature is controlled at 90-100℃ and the residence time is 1-3 min.

[0010] S3. After the reaction is complete, the discharged material is cooled to below 60°C and filtered to obtain the polybutadiene insulating resin;

[0011] The imidazole catalyst is 1-cyanoethyl-2-ethyl-4-methylimidazolium, 2-heptadecylimidazolium, or 2-phenylimidazolium.

[0012] Preferably, the continuous flow reactor in S2 is provided with a number of plates and agitators, the plates and agitators are arranged alternately, and the plates are used to hold catalysts.

[0013] Preferably, the continuous flow reactor in S2 has 8 layers, each layer is pre-added with a fixed amount of 100 grams of catalyst, and each layer is equipped with a stirring paddle on both sides and a discharge port at the top.

[0014] Preferably, the continuous flow reactor in S2 is provided with a heating layer around its periphery, with a heat medium inlet on one side and a heat source outlet on the other side.

[0015] Preferably, the continuous flow reactor is connected to the outlet end of the mixer via a pipeline, and the inlet end of the mixer is connected to the first feed pump and the second feed pump respectively.

[0016] Preferably, the continuous flow reactor is provided with a discharge port at the top.

[0017] Preferably, the diameter of the filter screen in step S3 is 100 micrometers.

[0018] The present invention also provides a UV-curable polybutadiene insulating resin.

[0019] Compared with the prior art, the advantages of this invention are:

[0020] 1. This invention uses polybutadiene resin with double-ended carboxyl groups and glycidyl ester or ether with double bonds to undergo a ring-opening esterification reaction, introducing highly reactive double bonds, which improves the reactivity and crosslinking density of polybutadiene resin during UV curing.

[0021] 2. A continuous flow reactor is used. The catalyst is added to the reactor plates, and there is a stirring paddle between each plate. The catalyst concentration is high enough, the reactor temperature is controlled at 90-100℃, and the ring-opening esterification reaction can be completed in 1-3 minutes. The production efficiency is high, the catalyst can be reused, and the resin product has high quality.

[0022] 3. Polybutadiene itself has excellent insulation properties, but its double bond activity is low. The modified resin can be used as the main resin in UV coatings. Attached Figure Description

[0023] Figure 1 The diagram shows the structure of the mixer and the continuous flow reactor in the continuous flow preparation process of this invention.

[0024] 1. Continuous flow reactor; 2. Mixer; 3. Sheet plate; 4. Stirring paddle; 5. Catalyst; 6. Heating layer; 7. Heat medium inlet; 8. Heat source outlet; 9. Mixer outlet end; 10. First feed pump; 11. Second feed pump; 12. Discharge port; 13. Rotary shaft. Detailed Implementation

[0025] To make the objectives and principles of this invention clearer, the following description, in conjunction with the accompanying drawings and specific embodiments, will provide further details.

[0026] The preparation process of the embodiments provided by the present invention is as follows: Figure 1 As shown, this invention employs a 5L continuous flow reactor 1, comprising 8 layers 3 and 9 agitators 4, with the layers 3 and agitators 4 arranged alternately and connected by a rotating shaft 13. Each layer 3 is filled with 100 grams of catalyst 5. The effective volume of the continuous flow reactor 1 is 3.5L. A heating layer 6 is provided around the periphery of the continuous flow reactor 1. A discharge port 12 is provided on the upper right side of the heating layer 6, a heat medium inlet 7 is provided on the lower right side, and a heat source outlet 8 is provided on the upper left side. The continuous flow reactor 1 is connected to a mixer outlet 9 via a pipe. The mixer inlet is connected to a first feed pump 10 and a second feed pump 11, respectively, to process the double-ended carboxylates. The polybutadiene resin is fed into the first feed pump 10, and the glycidyl ester (ether) with double bonds is fed into the second feed pump 11. The flow rate of the feed pump is set, and the volume ratio (5.3-19.7:1) is calculated. After mixing in the mixer 2, the mixture enters the continuous flow reactor 1 and the shelf 3, and stays for 1-3 minutes. The reaction temperature in the continuous flow reactor 1 is controlled by the heating layer 6, the heat medium inlet 7, and the heat source outlet 8. The reaction temperature is controlled at 90-100℃. After the reaction is completed, the mixture is discharged from the outlet 12. The outlet 12 is cooled to below 60℃ and filtered with a 100-micron filter to obtain UV-curable polybutadiene insulating resin.

[0027] Taking the reaction of carboxyl-terminated polybutadiene resin and allyl glycidyl ether as an example, the specific reaction formula is as follows:

[0028]

[0029] Examples 1-6

[0030] The preparation process conditions for Examples 1-6 are shown in Table 1 below:

[0031] Table 1

[0032]

[0033]

[0034] In Examples 1-6, the units for different molecular weights of the bicarboxylated polybutadiene resin and the raw materials of glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether are milliliters per minute. When two raw materials are used simultaneously in the formulation, they need to be mixed in advance before entering the pump.

[0035] Example 7

[0036] This embodiment uses a traditional batch reactor. Using the raw materials and proportions of Example 1, 2944.44 ml of carboxyl-terminated polybutadiene resin Mn1000-2000 and 555.56 ml of glycidyl methacrylate were added to a conventional reactor with an effective volume of 5 liters. 35 g of catalyst 2-heptadecylimidazol was added. The reaction temperature was raised to 145°C. After reacting for 4 hours, the temperature was lowered to below 60°C before the product was discharged.

[0037] Example 8

[0038] This embodiment uses a traditional batch reactor, with the same raw materials and proportions as in Example 1, but with the addition of a polymerization inhibitor. 2944.44 ml of carboxyl-terminated polybutadiene resin Mn1000-2000 and 555.56 ml of glycidyl methacrylate are added to a conventional reactor with an effective volume of 5 liters. 35 g of catalyst 2-heptadecylimidazol and 20 g of polymerization inhibitor hydroquinone are added. The reaction temperature is raised to 145°C, and after reacting for 4 hours, the temperature is lowered to below 60°C before discharge.

[0039] Example 9

[0040] This embodiment uses a traditional batch reactor, with the same raw materials and proportions as in Example 3, but with the addition of a polymerization inhibitor. 3172.90 ml of carboxyl-terminated polybutadiene resin Mn2000-3000 and 327.10 ml of glycidyl acrylate are added to a conventional reactor with an effective volume of 5 liters. 35 g of catalyst 2-heptadecylimidazol and 20 g of polymerization inhibitor hydroquinone are added. The reaction temperature is raised to 145°C, and after reacting for 4 hours, the temperature is lowered to below 60°C before discharge.

[0041] The technical specifications of the UV-curable polybutadiene insulating resins prepared in Examples 1-9 above are compared in Table 2 below:

[0042] Table 2

[0043] project Appearance Viscosity (25℃) Epoxy equivalent unit / mPa.s g / eq standard transparent liquid 500-5000 Undetectable Example 1 transparent liquid 852 Undetectable Example 2 transparent liquid 4290 Undetectable Example 3 transparent liquid 1379 Undetectable Example 4 transparent liquid 3102 Undetectable Example 5 transparent liquid 2774 Undetectable Example 6 transparent liquid 1785 Undetectable Example 7 Gel liquid 23560 Undetectable Example 8 transparent liquid 4753 Undetectable Example 9 transparent liquid 7628 Undetectable

[0044] The data above shows that the UV-curable polybutadiene insulating resin prepared by the continuous flow method of this invention has lower viscosity, no catalyst residue, better quality, and higher production efficiency compared with the resin prepared by traditional batch reactor. Based on the effective volume of 3.5L of a 5L continuous flow reactor and a residence time of 2min, the production yield in 24 hours is 2520L, while the production yield of the traditional batch reactor in 24 hours is 21L, indicating higher production efficiency.

[0045] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the invention, based on the technical solutions and novel concepts of the invention, should be covered within the scope of protection of the invention.

Claims

1. A continuous flow preparation method for a UV-curable polybutadiene insulating resin, characterized in that, Includes the following steps: S1. The double-ended carboxyl polybutadiene resin and glycidyl ester or ether containing double bonds are mixed evenly in a mixer at a volume ratio of 5.3-19.7:1, wherein: The molecular weight Mn of the double-ended carboxyl polybutadiene resin is 1000-5000; The glycidyl ester or ether with double bonds is selected from at least one of glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether. S2. The mixture is fed into a continuous flow reactor for ring-opening esterification reaction. The continuous flow reactor is equipped with multiple layers of plates, each layer of which is filled with an imidazole catalyst. The reaction temperature is controlled at 90-100℃ and the residence time is 1-3 min. S3. After the reaction is complete, the discharged material is cooled to below 60°C and filtered to obtain the polybutadiene insulating resin; The imidazole catalyst is 1-cyanoethyl-2-ethyl-4-methylimidazolium, 2-heptadecylimidazolium, or 2-phenylimidazolium.

2. The continuous flow preparation method of UV-curable polybutadiene insulating resin as described in claim 1, characterized in that, The continuous flow reactor in S2 is equipped with several layers and a stirring paddle, which are arranged alternately. The layers are used to hold a catalyst.

3. The continuous flow preparation method of UV-curable polybutadiene insulating resin as described in claim 2, characterized in that, The continuous flow reactor in S2 is provided with a heating layer around its periphery. A heat medium inlet is provided on one side of the heating layer, and a heat source outlet is provided on the other side.

4. The continuous flow preparation method of UV-curable polybutadiene insulating resin as described in claim 2, characterized in that, The continuous flow reactor is connected to the outlet of the mixer via a pipeline, and the inlet of the mixer is connected to the first feed pump and the second feed pump respectively.

5. The continuous flow preparation method of UV-curable polybutadiene insulating resin as described in claim 2, characterized in that, The continuous flow reactor is provided with a discharge port at the top.

6. The continuous flow preparation method of a UV-curable polybutadiene insulating resin as described in claim 1, characterized in that, In step S3, the filter screen diameter is 100 micrometers.

7. A UV-curable polybutadiene insulating resin prepared by a continuous flow preparation method of a UV-curable polybutadiene insulating resin as described in any one of claims 1-3.

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