A micro-crosslinked high molecular weight high heat resistance brominated epoxy resin and a preparation method thereof

Abstract

The application discloses a kind of micro-crosslinking high molecular weight high heat resistance brominated epoxy resin and its preparation method;The brominated epoxy resin is first polymerized with tetra-bromobisphenol A glycidyl ether or low molecular weight brominated epoxy resin and tetra-bromobisphenol A under the action of catalyst, obtain high molecular weight brominated epoxy resin;Or directly using ordinary high molecular weight brominated epoxy resin;Then by high molecular weight brominated epoxy resin and polyepoxy compound and / or acid anhydride compound melt addition polymerization, by the addition reaction between reactants obtain higher molecular weight, higher thermal stability and a certain degree of crosslinking brominated epoxy resin, simultaneously obtain higher glass transition temperature.The brominated epoxy resin can be used for flame-retardant nylon, polyester and other materials, with higher thermal stability, higher heat resistance, and can also improve melt viscosity.The preparation process of the application is simple, and the processing condition is stable, and the brominated epoxy resin with weight average molecular weight of more than 30,000 and high thermal stability can be prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to a micro-crosslinked high-molecular-weight high-heat-resistant brominated epoxy resin and a preparation method thereof, and belongs to the technical field of polymeric flame retardants for plastic additives and their synthesis and preparation, and specifically relates to chain extension and high-molecular-weight and heat-resistant stabilization of brominated epoxy resin. BACKGROUND

[0002] Brominated epoxy resins are divided into two major categories: one is low-molecular-weight, low-bromine epoxy resin used as a flame-retardant adhesive material for copper-clad plates, with a bromine content of 18%-20% and a molecular weight of <1000; the other is high-molecular-weight, high-bromine epoxy resin used as a flame-retardant additive for high-molecular-weight materials, with a bromine content of (49%-58%) and a weight average molecular weight of 1400 or more and 25000 or less, and foreign companies also have products with a weight average molecular weight of 30000 or more; the brominated epoxy resin involved in the present application belongs to brominated epoxy resin used as an additive for polymers such as plastics.

[0003] Molecular structure of brominated epoxy resin:

[0004]

[0005] When n=0, the molecular formula is tetrabromobisphenol A glycidyl ether.

[0006] The brominated epoxy resins reported at home and abroad all use single tetrabromobisphenol A, tetrabromobisphenol A glycidyl ether and epichlorohydrin as main raw materials, and use ring-opening addition reaction of epoxy groups and phenolic hydroxyl groups to realize polymerization reaction, thereby preparing high-molecular-weight brominated epoxy resin.

[0007] The present technical inventor Qian Lijun published a paper in the fifth issue of Plastics in 2003, the paper name is Synthesis of Brominated Epoxy Resin for Flame Retardant Additives, which introduces in detail the two-step synthesis method from tetrabromobisphenol A glycidyl ether to high-molecular-weight brominated epoxy resin, and the present technical inventor also introduced the preparation method of brominated epoxy resin in the book Modern Flame Retardant Materials and Technology published in 2022.

[0008] The preparation methods of brominated epoxy resin applied subsequently, such as CN116178674A, disclose a kind of brominated epoxy resin and its preparation method, which are basically similar to the preparation method in the paper mentioned above in 2003.

[0009] In addition, the patent application CN118620182A entitled "Preparation method of high heat-resistant brominated epoxy resin flame retardant" discloses a preparation method of high heat-resistant brominated epoxy resin flame retardant. 140-160 parts by mass of bisphenol-type diglycidyl ether, 1-30 parts by mass of tetrabromobisphenol A, 1-15 parts by mass of bisphenol A, 20-155 parts by mass of tribromophenol, and 120-300 parts by mass of solvent are added to a reactor, stirred and heated to 60-90°C, then 0.08-0.16 parts by mass of catalyst is added, the temperature is maintained for 1.5-3.5 hours, then the temperature is raised to 60-130°C (with heat preservation) for 3-8 hours, then the solvent is distilled off, and the high heat-resistant brominated epoxy resin flame retardant is prepared. The application mentions that the prepared high heat-resistant brominated epoxy resin flame retardant is suitable for the field of engineering plastics such as HIPS and ABS, and has excellent flame retardancy, heat resistance, and good processing performance.

[0010] The above preparation method and structural components are similar to the previous brominated epoxy resin, but bisphenol A and tribromophenol are added. The brominated epoxy resin prepared by this method is similar to the EC type brominated epoxy resin capped with tribromophenol, and the thermal stability is similar to that of the general high molecular brominated epoxy resin.

[0011] Therefore, in order to further realize the high molecular weight and high thermal stability of the brominated epoxy resin, there is no report on the preparation of special brominated epoxy resin by using multiple flame-retardant groups in the field of brominated epoxy resin, and there is also no preparation technology of high molecular weight brominated epoxy resin by using multiple reaction functional groups. The main reason is that the viscosity of the reactant is large, and after the molecular weight exceeds 25000, there are great implementation obstacles in the polymerization reaction equipment. SUMMARY

[0012] The micro-crosslinked high molecular weight high heat-resistant brominated epoxy resin according to the present application is a brominated epoxy resin with a micro-crosslinked structure formed by further chain extension and crosslinking of the brominated epoxy resin using a multi-epoxy compound or an anhydride compound or a mixture of the two, which is referred to as HBEP. The molecular weight is higher than 30000, and it has the performance characteristics of high melt viscosity and high thermal stability.

[0013] The structural features of HBEP include: the structure formed by the ring-opening addition reaction of the hydroxyl group in the brominated epoxy resin with the epoxy group in the polyepoxide compound; the structure formed by the addition reaction of the hydroxyl group in the brominated epoxy resin with the acid anhydride compound, and then the ring-opening addition reaction of the carboxyl group with the epoxy group in the brominated epoxy resin; or the above features coexist; in addition, due to the complexity of the addition reaction of the brominated epoxy resin with the polyepoxide compound or the acid anhydride compound, and the existence of double bonds in some polyepoxide compounds or acid anhydride compounds, double bond polymerization may occur, so the structural features of HBEP include but are not limited to the above structural features.

[0014] The main raw materials involved in all the methods of the present application are tetra-bromobisphenol A glycidyl ether, low molecular weight brominated epoxy resin (weight average molecular weight of 700-2000), medium molecular weight brominated epoxy resin (weight average molecular weight of 2000-8000), high molecular weight brominated epoxy resin (weight average molecular weight of 8000-25000), tetra-bromobisphenol A, polyepoxide compound, acid anhydride compound, and polymerization catalyst.

[0015] The preparation methods of HBEP are divided into two categories according to the raw materials: the first category is to use tetra-bromobisphenol A glycidyl ether or low or medium molecular weight brominated epoxy resin as the main brominated epoxy resin raw material, and the second category is to use high molecular weight brominated epoxy resin as the main brominated epoxy resin raw material; the first category is to react tetra-bromobisphenol A glycidyl ether or low or medium molecular weight brominated epoxy resin with tetra-bromobisphenol A under the catalysis of a polymerization catalyst to form high molecular weight brominated epoxy resin, and then to melt and add polyepoxide compound or acid anhydride compound or a mixture of the two to polymerize and chain-extend to prepare micro-crosslinked brominated epoxy resin with higher molecular weight and higher thermal stability; the second category is to further melt and add polyepoxide compound or acid anhydride compound or a mixture of the two to polymerize and chain-extend high molecular weight brominated epoxy resin under the catalysis of a polymerization catalyst to prepare micro-crosslinked brominated epoxy resin with higher molecular weight and higher thermal stability. Specifically:

[0016] The first category of preparation method is to heat and melt tetra-bromobisphenol A glycidyl ether or low or medium molecular weight brominated epoxy resin, add tetra-bromobisphenol A at a mass ratio of 100:1-75, add 0.1%-2% of the mass of the reactants of polymerization catalyst, stir the reactants in a polymerization reactor, heat to 100-220 degrees, and react for 30 minutes-5 hours; then introduce the reactants into a screw reactor, add 0.01%-5% of the mass of the reactants of polyepoxide compound or acid anhydride compound, and perform screw extrusion chain extension reaction at 150-250 degrees; the equipment used is a screw extruder, and high molecular weight high heat-resistant brominated epoxy resin with a molecular weight of more than 30000 is obtained.

[0017] The second type of preparation method is to add high molecular weight brominated epoxy resin (weight average molecular weight 8000-25000) into a screw reactor, while adding 0.1%-2% of the mass of the high molecular weight brominated epoxy resin of a polymerization catalyst, and adding 0.01%-5% of the mass of the high molecular weight brominated epoxy resin of a multi-epoxy compound or an acid anhydride compound, and performing screw extrusion chain extension reaction at 150-250 degrees. The equipment used is a screw extruder, and a high molecular weight high heat-resistant brominated epoxy resin with a molecular weight of 30000 or more is obtained.

[0018] Preferably, the multi-epoxy compound is one or more of 2,4,6-tris(oxirane-2-ylmethoxy)-1,3,5-triazine, tris(oxirane-2-ylmethyl)benzene-1,3,5-tricarboxylate, isocyanuric acid triglycidyl ester, pentaerythritol tetraglycidyl ether, and 1,4-bis[(glycidyloxy)methyl]cyclohexane.

[0019] Preferably, the acid anhydride compound is one or more of maleic anhydride, phthalic anhydride, and itaconic anhydride.

[0020] Preferably, the polymerization catalyst is one or more of triphenyl phosphine, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraphenylammonium chloride, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, triphenylbenzylphosphonium chloride, triphenylbutylphosphonium chloride, triphenylmethylphosphonium chloride, tertiary phosphonium salt, quaternary ammonium salt, and quaternary phosphonium salt.

[0021] Preferably, the screw extruder is a single-screw extruder, a twin-screw extruder, or a triple-screw extruder, and the screw extruder has a heating module to provide constant temperature heating to the material.

[0022] Advantages:

[0023] The high molecular weight high heat-resistant brominated epoxy resin HBEP of the present application has the advantages of high molecular weight, high viscosity, and high thermal stability, and is particularly suitable for flame retardation of nylon and polyester materials, can achieve better compatibility with the above-mentioned materials during processing, and has a certain tackifying effect on nylon or PBT and other materials with high melt index under high temperature conditions, so that the HBEP flame-retardant nylon or PBT has a moderate melt flow rate. The preparation method of the present application is simple and feasible, and the thermal effect is safe and controllable. In the process of chain extension of the high molecular weight brominated epoxy resin, a screw extruder is used as the processing equipment to overcome the problem of high viscosity and difficult processing of the high molecular weight brominated epoxy resin, and industrialized mass production can be realized. The production process is green and pollution-free, and no three wastes are discharged.

[0024] The high molecular weight high heat resistant brominated epoxy resin HBEP of the present application, whose weight average molecular weight is increased from 25000 or less of common high molecular brominated epoxy resin to 30000-60000, and has high thermal stability, 1% initial decomposition temperature is increased from 330-340 to 350-380 degrees, which is 20-30 degrees higher than that of traditional high molecular weight brominated epoxy resin, which plays an important role in the processing of high temperature resistant flame retardant polymers; the glass transition temperature (DSC test) of HBEP is increased by 30-50 degrees compared with traditional high molecular weight brominated epoxy resin; the melt viscosity is increased, which can significantly increase the heat distortion temperature of flame retardant polymers by 5-10 degrees; in the process of flame retardant nylon and PBT, the melt viscosity is increased by 10-20% compared with traditional high molecular weight brominated epoxy resin at processing temperature. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Infrared spectrum of high molecular weight high heat stable brominated epoxy resin obtained in Example 4;

[0026] Figure 2 DSC curve of high molecular weight high heat stable brominated epoxy resin obtained in Example 4;

[0027] Figure 3 Thermogravimetric curve of high molecular weight high heat stable brominated epoxy resin obtained in Example 4. DETAILED DESCRIPTION

[0028] The present application will be further described below in conjunction with examples; these examples are only used to illustrate the present application and not to limit the scope of the present application; the experimental methods in the following example embodiments are not specified, which are usually according to the conventional conditions in the art; the raw materials, reagents, etc. used, if not specifically stated, are commercially available raw materials and reagents; any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.

[0029] Example 1

[0030] After 200 kg of high molecular weight brominated epoxy resin (molecular weight 15000) is added to a twin-screw reactor, 0.1% (0.2 kg) of the polymerization catalyst tetrabutylammonium chloride and 0.6% (4.8 kg) of isocyanuric acid triglycidyl ester of the brominated epoxy resin are added, and screw extrusion chain extension reaction is carried out at 190 degrees. The equipment used is a screw extruder, and a high molecular weight high heat-resistant brominated epoxy resin with a weight average molecular weight of 41000 is obtained. The 1% initial decomposition temperature can reach 355 degrees, and the glass transition temperature is 166 degrees. In the process of flame-retardant PBT, the melt viscosity can be increased by 11% at a processing temperature of 220 degrees.

[0031] Example 2

[0032] After 200 kg of high molecular weight brominated epoxy resin (molecular weight 15000) is added to a twin-screw reactor, 0.1% (0.2 kg) of the polymerization catalyst tetrabutylammonium chloride and 0.6% (4.8 kg) of isocyanuric acid triglycidyl ester of the brominated epoxy resin are added, and screw extrusion chain extension reaction is carried out at 190 degrees. The equipment used is a screw extruder, and a high molecular weight high heat-resistant brominated epoxy resin with a weight average molecular weight of 41000 is obtained. The 1% initial decomposition temperature can reach 355 degrees, and the glass transition temperature is 166 degrees. In the process of flame-retardant PBT, the melt viscosity can be increased by 11% at a processing temperature of 220 degrees.

[0033] Example 3

[0034] After 200 kg of high molecular weight brominated epoxy resin (molecular weight 15000) is added to a twin-screw reactor, 0.1% (0.2 kg) of the polymerization catalyst tetrabutylammonium chloride and 0.6% (4.8 kg) of isocyanuric acid triglycidyl ester of the brominated epoxy resin are added, and screw extrusion chain extension reaction is carried out at 190 degrees. The equipment used is a screw extruder, and a high molecular weight high heat-resistant brominated epoxy resin with a weight average molecular weight of 41000 is obtained. The 1% initial decomposition temperature can reach 355 degrees, and the glass transition temperature is 166 degrees. In the process of flame-retardant PBT, the melt viscosity can be increased by 11% at a processing temperature of 220 degrees.

[0035] Example 4

[0036] 100kg brominated epoxy resin with weight average molecular weight of 22000 was added into a screw reactor, 100g of catalyst triphenyl benzyl phosphonium chloride with 0.1% of the mass of the high molecular weight brominated epoxy resin was added, 200g of maleic anhydride was added, and a double screw extrusion chain extension reaction was carried out at 210 degrees to obtain a high molecular weight high heat resistant brominated epoxy resin with a weight average molecular weight of 58000, a 1% initial decomposition temperature of 367.7 degrees, and a glass transition temperature of 183.2 degrees; in the process of flame-retardant nylon 66, the melt viscosity can be increased by 17% at a processing temperature of 270 degrees.

[0037] Example 5

[0038] After 100kg of tetra-bromobisphenol A glycidyl ether was heated and melted, 72kg of tetra-bromobisphenol A was added, 0.4kg of polymerization catalyst tetraphenyl ammonium chloride was added, the reaction was carried out in a polymerization reactor by stirring and heating to 160 degrees, after stirring and heating for 90 minutes, the reaction was introduced into a screw reaction extruder, 0.8% of the mass of the reaction was added, and a single screw extruder was used for extrusion chain extension reaction at 190 degrees to obtain a high molecular weight high heat resistant brominated epoxy resin with a weight average molecular weight of 39000; the 1% initial decomposition temperature can reach 362 degrees, the glass transition temperature is 158 degrees; in the process of flame-retardant PBT, the melt viscosity can be increased by 10% at a processing temperature of 220 degrees.

[0039] Example 6

[0040] 50kg of high molecular weight brominated epoxy resin (weight average molecular weight 25000) was added into a double screw extruder, 0.2kg of polymerization catalyst triphenyl butyl phosphonium chloride and 0.5kg of maleic anhydride were added, and an extrusion chain extension reaction was carried out at 180 degrees to obtain a high molecular weight high heat resistant brominated epoxy resin with a weight average molecular weight of more than 45000, a 1% initial decomposition temperature of 375 degrees, and a glass transition temperature of 381 degrees; in the process of flame-retardant nylon 66, the melt viscosity can be increased by 18% at a processing temperature of 260 degrees.

[0041] The above examples are only some of the preferred schemes of the present application, but they are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of the present application.

Claims

1. A method for preparing a micro-crosslinked, high-molecular-weight, high-heat-resistant brominated epoxy resin, characterized in that, The micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin (HBEP) is formed by chain extension and crosslinking of high molecular weight brominated epoxy resin with polyepoxy compounds or acid anhydride compounds or mixtures thereof. HBEP has a weight-average molecular weight of 30,000 or more. The high molecular weight brominated epoxy resin is a brominated epoxy resin with a weight-average molecular weight of 8,000-25,000, or a high molecular weight brominated epoxy resin obtained by reacting medium-low molecular weight brominated epoxy resin with a weight-average molecular weight not exceeding 8,000 with tetrabromobisphenol A under the catalysis of a catalyst. HBEP has a higher molecular weight and higher thermal stability than the high molecular weight brominated epoxy resin.

2. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 1, characterized in that, HBEP contains structural features resulting from the addition reaction of high molecular weight brominated epoxy resins with polyepoxides or acid anhydrides, including: The structure is formed by the ring-opening addition reaction of hydroxyl groups in brominated epoxy resin with polyepoxides; The structure is formed by the addition reaction of the hydroxyl group in the brominated epoxy resin with the acid anhydride compound, and the carboxyl group formed therefrom further undergoing a ring-opening addition reaction with the epoxy group of the brominated epoxy resin, either wholly or partially. Or the above structures may coexist.

3. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 1, characterized in that, The method includes: heating and melting tetrabromobisphenol A glycidyl ether and / or brominated epoxy resin with a weight average molecular weight of 700-8000, adding tetrabromobisphenol A at a mass ratio of 100:1-75, adding 0.1%-2% of polymerization catalyst by mass of reactants, stirring and heating the reactants in a polymerization reactor to 100-220 degrees Celsius for reaction, and after 30 minutes to 5 hours, introducing the obtained reactants into a screw reactor, and simultaneously adding 0.01%-5% of polyepoxide compound or acid anhydride compound by mass of the obtained reactants, and carrying out a screw extrusion chain extension reaction at 150-250 degrees Celsius. The equipment used is a screw extruder, to obtain a high molecular weight, high heat-resistant brominated epoxy resin with a molecular weight of over 30,000.

4. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 1, characterized in that, The method includes: adding brominated epoxy resin with a weight-average molecular weight of 8000-25000 to a screw reactor, along with 0.1%-2% by mass of a polymerization catalyst and 0.01%-5% by mass of a polyepoxide compound or anhydride compound, and carrying out a screw extrusion chain extension reaction at 150-250 degrees Celsius. The equipment used is a screw extruder, to obtain a high molecular weight, high heat-resistant brominated epoxy resin with a molecular weight of over 30000.

5. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 1, characterized in that, The polyepoxide compound is one or more of 2,4,6-tris(ethylene oxide-2-ylmethoxy)-1,3,5-triazine, tris(ethylene oxide-2-ylmethyl)benzene-1,3,5-tricarboxylic acid ester, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether, and 1,4-bis[(glycidoxy)methyl]cyclohexane.

6. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 1, characterized in that, The acid anhydride compound is one or more of maleic anhydride, phthalic anhydride, and itaconic anhydride.

7. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 3 or 4, characterized in that, The polymerization catalyst is one or more of tertiary phosphorus or tertiary phosphorus salts, quaternary ammonium salts, and quaternary phosphorus salts, selected from triphenylphosphine, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraphenylammonium chloride, tetrabutylphosphine chloride, tetrabutylphosphine bromide, triphenylbenzylphosphine chloride, triphenylbutylphosphine chloride, and triphenylmethylphosphine chloride.

8. The method for preparing the micro-crosslinked high molecular weight, high heat-resistant brominated epoxy resin according to claim 3 or 4, characterized in that, The screw extruder is a single-screw extruder, a twin-screw extruder, or a three-screw extruder. The screw extruder has a heating module that can heat the material at a constant temperature.

9. A micro-crosslinked, high-molecular-weight, high-heat-resistant brominated epoxy resin, characterized in that, It is prepared by the method described in any one of claims 1-8.

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