Preparation method of halogen-free epoxy resin

Abstract

The invention discloses a preparation method of halogen-free epoxy resin, which comprises the following step: carrying out nucleophilic substitution reaction on a compound shown in a formula I and a compound shown in a formula II under the action of a catalyst to prepare epoxy resin shown in a formula III. The method disclosed by the invention is simple to operate, the post-treatment does not need complicated halogen removal and purification operation, and the prepared halogen-free epoxy resin material is free of halogen residues, extremely high in purity, free of residual phosphate raw materials, free of corrosion of circuits and electronic devices and capable of being applied to the field of advanced electronic packaging. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of thermosetting resins, and in particular relates to an epoxy resin without halogen residue and a preparation method thereof. Background Art

[0002] Epoxy resin is an important thermosetting resin formed by cross-linking epoxy monomers and curing agents, accounting for more than 70% of the thermosetting market share. Epoxy monomers usually refer to glycidyl ethers, glycidyl esters, or glycidyl amines containing at least two epoxy groups, including high-purity compounds and prepolymers with low polymerization degrees.

[0003] Epoxy resin has become the most important resin-based material for electronic packaging due to its excellent chemical stability, dielectric properties, thermal properties and mechanical properties. Among them, bisphenol A diglycidyl ether (DGEBA) is the most important epoxy monomer used for electronic packaging. At present, the industrial production method of DGEBA is mainly to open the ring of epichlorohydrin under alkaline conditions, condense with bisphenol A to obtain a β-chloroethanol oxygen anion structure, and then undergo an intramolecular nucleophilic substitution reaction to remove the chloride ion to obtain the target monomer. However, in the actual production process, due to incomplete ring closure reaction, the monomer contains chloride ions, which are usually called hydrolyzable chlorine. In the actual application of epoxy resin as a packaging material, hydrolyzable chlorine is hydrolyzed under high temperature and high humidity conditions, and the precipitation of chloride ions corrodes electronic devices. Therefore, the need to prepare epoxy monomers with low hydrolyzable chlorine (<50ppm) or chlorine-free is very urgent.

[0004] At present, there are two main methods to reduce the content of hydrolyzable chlorine in epoxy monomers. The first is to change the synthesis route of epoxy monomers, that is, to prepare compounds with terminal double bonds, and use strong oxidants such as meta-chloroperbenzoic acid to epoxidize the double bonds to obtain halogen-free epoxy monomers. Although the strategy of double bond epoxidation fundamentally solves the problem of residual hydrolyzable chlorine, the use of a large amount of oxidants, complex post-treatment procedures, and the chemical structure of the product is different from that of DGEBA, which leads to incompatibility of resin processing technology in applications, making it difficult to actually use it in industrial production. The second method is to post-treat the product with strong alkalis such as sodium hydroxide and sodium hydride to hydrolyze the residual chlorine. However, this method not only produces a large amount of wastewater, but also causes some epoxy groups to open during the treatment of strong alkaline solutions, thereby reducing the epoxide value of the epoxy monomer. Summary of the invention

[0005] The present invention aims to solve the problem of difficulty in removing hydrolyzable chlorine from epoxy resin and proposes a method for directly synthesizing halogen-free epoxy resin. The method uses phosphorus-containing glycidyl ester which will not corrode electronic circuit components, chips and other components as a raw material to replace epichlorohydrin. The phosphorus-containing glycidyl ester is synthesized by a one-step esterification reaction of bio-based raw material glycidol and phosphoric acid, and then reacted with diol or diphenol to obtain a halogen-free electronic grade epoxy resin through a one-step nucleophilic substitution reaction. Since the reaction process does not involve the ring opening of epoxy, the high purity of the epoxy resin product is also guaranteed.

[0006] The technical solution provided by the present invention is:

[0007] A method for preparing a halogen-free epoxy resin comprises the following steps: a compound represented by formula I and a compound represented by formula II undergo a nucleophilic substitution reaction under the action of a catalyst to prepare an epoxy resin represented by formula III.

[0008]

[0009] In Formula I, A is selected from one of the following structures:

[0010]

[0011] Wherein R1 and R2 are each independently an unsubstituted or substituent-containing C1-C14 alkyl group; the substituent A may be one or more of a C1-C10 branched or linear alkoxy group, a C3-C20 branched or linear cycloalkyl group, and a C6-C10 aromatic group;

[0012] R3~R 14 Each independently does not exist, or is independently a C1-14 aliphatic carbon chain that is unsubstituted or contains a substituent B; the substituent B can be one or more of a C1-C10 branched or straight-chain alkoxy group, a C3-C20 branched or straight-chain cycloalkyl group, and a C6-C10 aromatic group.

[0013] In Formula I, B and C are each independently represented by any one or more of the following structures:

[0014]

[0015] Preferably, B and C have the same structure.

[0016] Preferably, the compound represented by formula I is bisphenol A.

[0017] In Formula II, R is selected from one of the following structures:

[0018]

[0019] Where R 15 -R17 Independently selected from the following groups which are unsubstituted or substituted by substituent C: C1-14 aliphatic carbon chain, C6-14 alicyclic group, C6-14 aromatic group, C3-14 heterocyclic group; the substituent C can be one or more of C1-C10 branched or straight-chain alkyl, C1-C10 branched or straight-chain alkoxy, C3-C20 branched or straight-chain cycloalkyl, C6-C10 aromatic group.

[0020] In the above chemical formula structures, The connection key.

[0021] In formula III, n is the degree of polymerization, 0 <n<50。

[0022] In formula II, m is the number of epoxy groups connected to the phosphate group, and m is 1, 2 or 3.

[0023] Preferably, the reaction temperature of the reaction is -60 to 120°C, preferably 50 to 80°C; the reaction time is 0.1 to 48h, preferably 0.5 to 5h.

[0024] Preferably, the reaction is carried out in the absence of a solvent or in a solvent; wherein the solvent is selected from one or more of tetrahydrofuran, benzene, toluene, hexane, diethyl ether, ethyl acetate, 1,4-dioxane, pyridine, acetonitrile, methanol and water.

[0025] Preferably, the ratio of the molar number of hydroxyl groups in the compound represented by formula I to the molar number of epoxy groups in the compound represented by formula II is between 1:1 and 100.

[0026] Preferably, the catalyst is selected from one or more of ammonium salts, phosphonium salts, imidazolium salts, carbonates and hydroxides.

[0027] More preferably, the structure of the catalyst is selected from one or more of the following.

[0028] M2CO3 MOH

[0029] NCO3 N(OH)2

[0030] Y2(CO3)3 Y((OH)3

[0031] M is selected from one or more of lithium, sodium, potassium, rubidium, cesium, and francium;

[0032] N is selected from one or more of beryllium, magnesium, calcium, strontium, barium, and radium;

[0033] Y is selected from one or more of aluminum, gallium, indium and thallium.

[0034] Preferred catalysts are sodium hydroxide or sodium carbonate.

[0035] The amount of the catalyst is 1 to 2 times, preferably 1.2 to 1.5 times, the molar amount of the hydroxyl group in the compound represented by formula I.

[0036] After the nucleophilic substitution reaction is completed, the reaction solution is post-treated to obtain the epoxy resin shown in formula III. The post-treatment method of the reaction solution is: the reaction solution is washed with deionized water, and a NaHCO3 solution is added to the obtained crude product. After heating and stirring for washing, it is vacuum dried to obtain the epoxy resin shown in formula III.

[0037] In the present invention, the compound represented by formula II can be prepared by esterification reaction of glycidol with a phosphoric acid compound having the following structure:

[0038]

[0039] The present invention also provides a halogen-free epoxy resin prepared by the method.

[0040] Preferably, the molecular weight distribution of the halogen-free epoxy resin is between 1.0 and 1.5.

[0041] The invention also provides application of the halogen-free epoxy resin in electronic packaging materials.

[0042] The present invention prepares a halogen-free epoxy resin by reacting an epoxy monomer containing a high leaving active group in the side chain with a diol. The product can be used for high-end packaging.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] (1) Since the epoxy side chain substituent has a strong leaving ability, compared with the epoxy resin prepared industrially by epichlorohydrin, the reaction of the present invention is carried out by a one-step nucleophilic substitution reaction, does not involve the ring opening of epoxy, and the product has an extremely low halogen content and an extremely high purity. When used for high-end packaging, no impurities will be generated during the use process to corrode circuits and electronic devices.

[0045] (2) The reaction method is simple to operate and does not require complicated physical or chemical dehalogenation processes in the later stages of the reaction.

[0046] (3) The product properties are easy to adjust. The degree of polymerization n of the product can be controlled by changing the reaction temperature, monomer feed ratio and catalyst, thereby achieving the control of the epoxy resin properties.

[0047] (4) The compound shown in the reaction raw material monomer formula II is a phosphate ester, which is synthesized by a one-step esterification reaction of a bio-based raw material glycidol and phosphoric acid, and the raw material does not contain any halogen. Phosphate ester has excellent leaving ability, and the raw material can be removed by washing. No phosphate ester will remain in the resin product, and no distillation purification is required, and the process is simple. Even if some of the raw materials remain, phosphorus is not corrosive to metals and will not corrode circuits and electronic devices. If sulfonates are used, sulfur may remain, which is corrosive to metals, and the post-processing process needs to adopt complex processes such as distillation, resulting in increased costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a picture of the halogen-free epoxy resin material obtained in Example 1.

[0049] Figure 2 This is the H NMR spectrum of the halogen-free epoxy resin product obtained in Example 1.

[0050] Figure 3 This is the nuclear magnetic phosphorus spectrum of the halogen-free epoxy resin obtained in Example 5.

[0051] Figure 4 This is a picture of the cured epoxy resin obtained in Example 5.

[0052] Figure 5 This is the dynamic mechanical analysis (DMA) curve of the cured epoxy resin obtained in Example 5. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific implementation methods. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention.

[0054] The general synthesis reaction formula of the halogen-free epoxy resin provided by the present invention is shown below.

[0055]

[0056] Examples 1-4

[0057]

[0058] The reaction parameters are shown in Table 1.

[0059] Dissolve bisphenol A (22.8 g, 0.1 mol) and dimethyl glycidyl phosphate (the molar ratio of phenolic hydroxyl group to epoxy group is 1:1, 1:2, 1:4 and 1:8 respectively) in ethyl acetate (100 mL), stir at 75 ° C for 10 min, then slowly add NaOH solution (1 M, 0.24 mol), continue heating and stirring after the addition is complete, and the reaction time is shown in Table 1. After the reaction is completed, cool to room temperature, take the organic phase and wash with deionized water. After the crude product is stirred at 60 ° C for 5 h in NaHCO3 solution (0.1 M, 100 mL), separate the layers, and take the organic phase and vacuum dry to obtain the following Figure 1 Shown is colorless viscous liquid DGEBA.

[0060] Table 1. Epoxy resins obtained under different reaction conditions

[0061]

[0062] like Figure 2 The figure shows the H NMR spectrum of DGEBA prepared in Example 4. The signals at 2.7-2.8ppm and 3.3ppm prove the epoxy functional groups in DGEBA, indicating that DGEBA has been successfully synthesized in this example. According to GB / T 4618.2-2008, the phosphate content of DGEBA was quantitatively analyzed using precipitation titration, and the results showed that the DGEBA synthesized in this example did not have any phosphate residue. In summary, it is shown that the halogen-free epoxy monomer has been successfully prepared.

[0063] Example 5

[0064] The reaction equation is shown below:

[0065]

[0066] Dissolve bisphenol A (22.8g, 0.1mol) and triglycidyl phosphate (53.2g, 0.2mol) in ethyl acetate (100mL), stir at 75℃ for 10min, then slowly add Na2CO3 solution (0.1M, 0.24mol), continue heating and stirring for 1h after the addition is complete. Cool to room temperature and wash with deionized water. Stir the crude product in NaHCO3 solution (0.1M, 100mL) at 60℃ for 5h, and vacuum dry to obtain colorless viscous liquid DGEBA. The n value of the obtained DGEBA is 0.05 and the molecular weight distribution is 1.06.

[0067] The purified product was tested by nuclear magnetic phosphorus spectrum, and the results were as follows Figure 3 As shown, the product has no absorption in the nuclear magnetic phosphorus spectrum, and a halogen-free epoxy resin with a high epoxy value is obtained.

[0068] The obtained halogen-free epoxy resin and isophorone diamine were uniformly mixed (the ratio of epoxy to amino was controlled to be 2:1), poured into a rectangular silicone mold, and placed in a blast drying oven for segmented curing to obtain a cross-linked epoxy resin. The specific steps of segmented curing are: heating at 60℃ for 1h, heating at 80℃ for 1h, heating at 100℃ for 1h, and heating at 120℃ for 1h. The appearance of the epoxy resin after curing is as follows Figure 4 The resin has extremely high transparency. The cured resin was subjected to dynamic thermal mechanical properties test (DMA). Figure 5 As shown. The glass transition temperature of the resin measured by the loss tangent curve is 153°C, which is comparable to the commercially available bisphenol A epoxy resin. In summary, the halogen-free epoxy resin has been successfully prepared and its performance is no different from that of the bisphenol A epoxy resin obtained by the traditional preparation method.

Claims

1. A method for preparing a halogen-free epoxy resin, characterized in that The method comprises: a compound represented by formula I and a compound represented by formula II are subjected to a nucleophilic substitution reaction under the action of a catalyst to prepare an epoxy resin represented by formula III; In Formula I, A is selected from one of the following structures: Wherein R1 and R2 are each independently an unsubstituted or substituent-containing C1-C14 alkyl group; the substituent A is one or more of a C1-C10 branched or straight-chain alkoxy group, a C3-C20 branched or straight-chain cycloalkyl group, and a C6-C10 aromatic group; R3~R 14 Each independently does not exist, or is independently a C1-14 aliphatic carbon chain that is unsubstituted or contains a substituent B; the substituent B is one or more of a C1-C10 branched or straight-chain alkoxy group, a C3-C20 branched or straight-chain cycloalkyl group, and a C6-C10 aromatic group; In Formula I, B and C are each independently represented by any one or more of the following structures: In Formula II, R is selected from one of the following structures: Where R 15 ~R 17 Independently selected from the following groups which are unsubstituted or substituted by substituent C: C1-14 aliphatic carbon chain, C6-14 alicyclic group, C6-14 aromatic group, C3-14 heterocyclic group; the substituent C is one or more of C1-C10 branched or straight chain alkyl, C1-C10 branched or straight chain alkoxy, C3-C20 branched or straight chain cycloalkyl, C6-C10 aromatic group; In formula III, n is the degree of polymerization, 0 <n<50; In formula II, m is 1, 2 or 3.

2. The method according to claim 1, characterized in that The ratio of the molar number of hydroxyl groups in the compound represented by formula I to the molar number of epoxy groups in the compound represented by formula II is between 1:1 and 100.

3. The method according to claim 1, characterized in that The catalyst is selected from one or more of ammonium salts, phosphonium salts, imidazolium salts, carbonates and hydroxides.

4. The method according to claim 3, characterized in that The structure of the catalyst is selected from one or more of the following: M2C03MOH NC03N(OH)2 Y2(COa)3Y(OH)3 M is selected from one or more of lithium, sodium, potassium, rubidium, cesium, and francium; N is selected from one or more of beryllium, magnesium, calcium, strontium, barium, and radium; Y is selected from one or more of aluminum, gallium, indium and thallium.

5. The method according to claim 3, characterized in that The amount of the catalyst is 1 to 2 times the molar amount of the hydroxyl group in the compound represented by formula I.

6. The method according to claim 1, characterized in that The reaction temperature of the reaction is -60 to 120° C., and the reaction time is 0.1 to 48 hours.

7. The method according to claim 1, characterized in that The reaction is carried out in the absence of solvent or in a solvent; the solvent is selected from one or more of tetrahydrofuran, benzene, toluene, hexane, ether, ethyl acetate, 1,4-dioxane, pyridine, acetonitrile, methanol and water.

8. The method according to claim 1, characterized in that After the nucleophilic substitution reaction is completed, the reaction solution is post-treated to obtain the epoxy resin shown in formula III. The post-treatment method of the reaction solution is: the reaction solution is washed with deionized water, and a NaHCO3 solution is added to the obtained crude product. After heating and stirring for washing, it is vacuum dried to obtain the epoxy resin shown in formula III.

9. The halogen-free epoxy resin prepared by the method according to any one of claims 1 to 8, wherein the molecular weight distribution of the halogen-free epoxy resin is between 1.0 and 1.

5.

10. Use of the halogen-free epoxy resin as claimed in claim 9 in electronic packaging materials.

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