Diprimary amine ionic flame retardant, synthetic method and application of diprimary amine ionic flame retardant in epoxy resin

Abstract

The invention belongs to the technical field of epoxy resin materials, and particularly relates to a bis-primary amine ionic flame retardant, a synthesis method and application of the bis-primary amine ionic flame retardant in epoxy resin. The preparation method comprises the following steps: reacting a bis-primary amine compound with DOPA in an alcohol solvent system at room temperature, and separating out a white powdery substance after the reaction is completed, so as to synthesize the novel flame retardant. In the chemical structural formula of the flame retardant, a bis-primary amine compound and DOPA are combined by electrostatic attraction to form an ionic compound. The flame retardant is directly mixed with a bisphenol A diglycidyl ether monomer and is used for preparing an epoxy resin material. The synthesized novel flame retardant is high in flame retardant efficiency, when the adding amount is smaller than 5 wt%, the oxygen index of an epoxy resin cured product can be increased to 30% or above, and vertical combustion passes the UL-94V-0 level. More importantly, the flame retardant is mild in preparation condition and high in yield, and compared with pure EP, the mechanical property of epoxy resin modified by the flame retardant is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resin materials, and in particular relates to a diprimary amine ion type flame retardant, a synthesis method and application thereof in epoxy resin. Background Art

[0002] Epoxy resin (EP) is a widely used thermosetting polymer material. Due to its excellent electrical insulation, corrosion resistance, high thermal stability, low shrinkage, strong adhesion and mechanical durability, it is widely used in electronic appliances, packaging, printed circuit boards, automobiles, adhesives and surface coatings. However, due to the large amount of C, H and N elements in EP, it is very easy to burn and has high safety risks, which limits its application in many fields. Therefore, while maintaining the unique properties of EP, enhancing the flame retardancy of EP has always been an important issue of concern.

[0003] At present, the most common and economical way to improve the flame retardancy of epoxy resin is to add flame retardants, and traditional additives are mostly halogen compounds. However, halogen compounds release a lot of smoke when burned, have great toxicity, and pose a serious threat to personal safety. Therefore, halogen flame retardants are gradually replaced by halogen-free flame retardants. Although a large number of added flame retardants reported in the prior art have improved the flame retardancy of epoxy resin, they are often accompanied by a decrease in other properties, especially a decrease in mechanical properties. In addition, most of the flame retardants reported require multi-step reactions during synthesis, or have low yields, and are not suitable for industrial applications.

[0004] Therefore, high-performance flame retardants that have high flame retardant properties and are cheap and economical have become one of the current research hotspots. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a diprimary amine ionic flame retardant, a synthesis method and application thereof in epoxy resin, aiming to solve some of the problems in the prior art or at least alleviate some of the problems in the prior art.

[0006] The present invention is achieved by a diprimary amine ionic flame retardant, comprising a compound of the following structural formula:

[0007] R=(CH2) n or Among them, n=3-16.

[0008] The present invention also provides a method for synthesizing the above-mentioned diprimary amine ionic flame retardant, wherein the diprimary amine compound and DOPA are combined with electrostatic attraction to form an ionic compound, and an amino group in the diprimary amine molecule is combined with H +, is positively charged, while the oxygen atom on the DOPA phosphorus hydroxyl group is negatively charged. The end of the compound away from DOPA contains an unbonded primary amine. The chemical equation is as follows:

[0009]

[0010] R=(CH2) n or Wherein, n = 3 to 16. The carbon chain of the R group has a value of n of 3 to 16 (straight chain or branched chain), or a structure in which two benzene rings are connected by a methyl group.

[0011] Furthermore, the reaction is carried out in an alcohol solvent at room temperature, and a white powdery substance is precipitated after the reaction.

[0012] Furthermore, the alcohol solvent is a low-carbon alcohol solvent selected from any one of methanol, ethanol, propanol or butanol.

[0013] Furthermore, the di-primary amine compound and DOPA are dissolved in an alcohol solvent respectively, and then the DOPA liquid is added dropwise to the di-primary amine compound liquid to react.

[0014] Furthermore, the molar ratio of the diprimary amine compound to DOPA is 1-1.2:0.8-1.0; the reaction temperature is room temperature 23-30°C; and the reaction time is 7-12 hours. Preferably, the reaction temperature is 25-30°C and the reaction time is 8 hours.

[0015] The present invention also provides the use of the above-mentioned diprimary amine ion flame retardant in the preparation of epoxy resin.

[0016] Furthermore, the epoxy resin is selected from any one of glycidyl ether epoxy resin, glycidyl ester epoxy resin and glycidyl amine epoxy resin, preferably bisphenol A epoxy resin.

[0017] Furthermore, after the bisphenol A diglycidyl ether and the P / N / S type flame retardant are fully reacted, a curing agent is added to obtain an epoxy resin with improved performance. The curing agent is preferably 4,4'-diaminodiphenylmethane (DDM).

[0018] Furthermore, the addition amount of the diprimary amine ionic flame retardant is 0.5-10 wt %, preferably 2-4 wt %.

[0019] The present invention uses diprimary amine and DOPA as main raw materials and synthesizes a new compound AP through a one-step reaction. When used for flame retardancy of epoxy resin, when the addition amount is only 4wt%, the best flame retardancy effect UL-V0 level can be achieved, and the mechanical properties are greatly improved compared with pure EP. Due to its unique properties and simple preparation method, it has considerable potential application value.

[0020] In summary, the advantages and positive effects of the present invention are:

[0021] 1. Compared with the prior art, this synthesis reaction method is simple, has high yield, no other by-products, mild reaction conditions, safe operation, low cost, and has great industrial value.

[0022] 2. Compared with the prior art, the flame retardant containing diprimary amine ionic compounds prepared by the present invention has higher flame retardant efficiency. When the addition amount is 4wt%, the oxygen index of epoxy resin cured product can be increased to 35.1%, and the vertical combustion passes UL-94V-0 level. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the infrared image of the diprimary amine ion type compound;

[0024] Figure 2 It is a diprimary amine ion compound 1 H NMR and 31 P NMR spectrum. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments. The equipment and reagents used in each embodiment and test example can be obtained from commercial sources unless otherwise specified. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Based on the information contained in this application, it is easy for those skilled in the art to make various changes to the precise description of the present invention without departing from the spirit and scope of the appended claims. It should be understood that the scope of the present invention is not limited to the defined process, properties or components, because these embodiments and other descriptions are only for illustrating specific aspects of the present invention. In fact, various changes that the technicians in this field or related fields can obviously make to the embodiments of the present invention are all covered within the scope of the appended claims.

[0027] In order to better understand the present invention but not to limit the scope of the present invention, all the numbers used in this application to express the amount, percentage, and other numerical values ​​should be understood as modified by the word "about" in all cases. Therefore, unless otherwise specified, the numerical parameters listed in the specification and the appended claims are approximate values, which may be changed according to the different ideal properties attempted to be obtained. Each numerical parameter should at least be regarded as obtained based on the reported significant figures and by conventional rounding methods.

[0028] The invention discloses a diprimary amine ion type flame retardant, a synthesis method and application of the same in epoxy resin.

[0029] It should be noted that the material parts in the following embodiments are all weight parts. The limiting oxygen index in the embodiments is tested using an HC-2C oxygen index tester in accordance with GB / T 2406-1993, and the vertical combustion is tested using a CZF-2 vertical combustion instrument in accordance with GB / T2408-1996. The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0030] Example 1 Synthesis of diprimary amine ionic flame retardant AP

[0031] Accurately weigh 5.9479g of 4,4'-diaminodiphenylmethane and place it in a 250mL three-necked flask, add 50mL of anhydrous ethanol, and completely dissolve it under magnetic stirring at room temperature. Measure 50mL of anhydrous ethanol, completely dissolve 6.9600g (10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPA), and drip it at a rate of 1 drop / 1s using a constant pressure funnel. React at room temperature for 8h. After the reaction is completed, a white powdery substance is precipitated. Filter, wash with anhydrous ethanol or deionized water several times, dry and weigh to obtain a white solid with a mass of 9.6443g and a yield of 74.72%. The chemical equation for the synthesis reaction is as follows:

[0032]

[0033] R=(CH2) n or Among them, n=3-16.

[0034] Figure 1 This is the infrared spectrum of the synthetic compound AP (the product synthesized by the reaction of DDM and DOPA). 1 H NMR and 31 PNMR diagram. Figure 1 Medium 3500-3250cm -1 The absorption peak at 3058 cm is the stretching vibration of primary amine. -1 The absorption peak at 2700-2380cm is the stretching vibration of benzene ring CH -1 The absorption peak at is NH 3+ Stretching vibration, 1722cm -1 The absorption peak at 1677cm-1 is the overtone of the benzene ring, and the absorption peak at 1677cm-1 is NH3 + The asymmetric angular vibration of NH 3+ Delta as Asymmetric deformation vibration, 1550-1450cm -1 The absorption peak at is NH 3+ Deltas Symmetrical deformation vibration, 1203cm -1 The absorption peak at 1130-975cm is the stretching vibration of P=O. -1 The absorption peak at 800-710cm is the in-plane bending vibration of the aromatic ring CH. -1 The absorption peak at is the out-of-plane bending vibration of the benzene ring CH. Figure 2 of 1 In the HNMR spectrum, the broad peak b at 8.70 ppm is attributed to NH 3+ The peak at 6.90-7.95ppm is attributed to the H on the benzene ring, and the peak b at 3.81ppm is attributed to the H on the methylene at a. 31 The single absorption peak of PNMR also shows that the reactants react in a 1:1 ratio. The above characterization clearly shows that AP was successfully synthesized. Compound AP is formed by diprimary amine and DOPA in the form of ionic bonds, in which the amino group in the diprimary amine molecule binds H + , is positively charged, while the oxygen atom on the phosphorus hydroxyl group of DOPA is negatively charged, and the two are combined into an ionic compound due to electrostatic attraction.

[0035] Example 2 Preparation of epoxy resin EP / 2AP

[0036] Under vacuum conditions, 77.8% of bisphenol A diglycidyl ether (DGEBA) was evacuated at 95°C until there were no bubbles. Then, 2% of powdered AP (AP was prepared by the reaction of DDM and DOPA) was quickly added. After rapid stirring to allow AP and EP to fully react, 20.2% of curing agent DDM was added. The obtained liquid was poured into a polytetrafluoroethylene (PTFE) mold and cured at 100°C and 150°C for 2 hours respectively to obtain an epoxy resin with an oxygen index test result of 31.8% and a vertical burning rating of UL-94V-1.

[0037] Example 3 Preparation of epoxy resin EP / 4AP

[0038] Under vacuum conditions, 76.2% of bisphenol A diglycidyl ether (DGEBA) was evacuated at 95°C until there were no bubbles. Then, 4.0% of powdered AP (AP was prepared by the reaction of DDM and DOPA) was quickly added. After rapid stirring to allow AP and EP to fully react, 19.8% of curing agent DDM was added. The obtained liquid was poured into a polytetrafluoroethylene (PTFE) mold and cured at 100°C and 150°C for 2h respectively to obtain an epoxy resin with an oxygen index test result of 35.1% and a vertical burning rating of UL-94V-0.

[0039] Example 4 Preparation of epoxy resin EP / 2AP'

[0040] Under vacuum conditions, 77.8% of bisphenol A diglycidyl ether (DGEBA) was evacuated at 95° C. until there were no bubbles. Then, 2% of powdered AP' (AP' was prepared by reacting 1,10-diaminodecane and DOPA under solvent-free conditions as described in Example 1) was quickly added, and AP' was rapidly stirred to allow AP' to fully react with EP. 20.2% of curing agent DDM was added, and the obtained liquid was poured into a polytetrafluoroethylene (PTFE) mold. The epoxy resin was cured at 100° C. and 150° C. for 2 hours, respectively, to obtain an epoxy resin with an oxygen index test result of 31.2% and a vertical burning rating of UL-94V-1.

[0041] Example 5 Preparation of epoxy resin EP / 4AP'

[0042] Under vacuum conditions, 76.2% of bisphenol A diglycidyl ether (DGEBA) was evacuated at 95°C until there were no bubbles. Then, 4% of powdered AP' (AP' was prepared by the reaction of 1,10-diaminodecane and DOPA) was quickly added and stirred rapidly to allow AP' and EP to react fully. Then, 19.8% of curing agent DDM was added and the obtained liquid was poured into a polytetrafluoroethylene (PTFE) mold. The epoxy resin was cured at 100°C and 150°C for 2 hours respectively to obtain an epoxy resin with an oxygen index test result of 32.4% and a vertical burning rating of UL-94V-0.

[0043] Comparative Example Preparation of Pure EP

[0044] Under vacuum conditions, 79.4% of bisphenol A diglycidyl ether (DGEBA) was evacuated at 95°C until there were no bubbles, 20.6% of curing agent DDM was added, and the mixture was stirred until uniform. The resulting liquid was poured into a polytetrafluoroethylene (PTFE) mold and cured at 100°C and 150°C for 2h respectively to obtain an epoxy resin with an oxygen index test result of 26.5%, and a vertical burning rating of UL-94 with no rating.

[0045] The mechanical properties of the epoxy resins prepared in the examples and comparative examples are also tested in this application. The relevant methods are: tensile test and three-point bending test are carried out on a CMT6103 universal testing machine according to the methods of GB / T 1040.2-2006 and GB / T 9341-2008 respectively. The tensile test uses a 75×4×2mm 3 The dumbbell-shaped specimen of the three-point bending test has a specimen size of 80×10×4mm 3 The value of each test is taken as the average of three tests. The test results are shown in Table 1 below.

[0046] Table 1: Effect of the diprimary amine ion-containing compound (AP) of the present invention on the mechanical properties of epoxy resin

[0047]

[0048] As can be seen from the above table, the tensile strength, elongation at break, flexural strength and flexural modulus of the new epoxy resin obtained by adding the new flame retardant containing diprimary amine ions to the epoxy resin of the present invention all increase with the increase of the amount of AP compound added in EP, and when the addition amount is 4%, its flexural strength is increased by 72% compared with pure EP. It has the characteristics of high flame retardant efficiency and excellent mechanical properties. The structure of the flame retardant has not been reported in the literature. The patent of the present invention provides a preparation method for epoxy resin flame retardant with low cost, simple operation and high reaction efficiency, which has potential application value.

[0049] The diprimary amines listed in the present invention include all raw materials containing diprimary amines as described in the patent description, and their structural characteristics are that in addition to containing ionic bonds, there is also an unbonded primary amine at one end. Examples are not listed here one by one. In addition to the synthesis method, additives with the same structural characteristics synthesized by other methods are also included.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A diprimary amine ionic flame retardant, characterized in that: Including compounds with the following structural formula: R=(CH2) n or Among them, n=3-16.

2. A method for synthesizing the diprimary amine ionic flame retardant as claimed in claim 1, characterized in that: The di-primary amine compounds and DOPA combine by electrostatic attraction to form ionic compounds. The chemical equation is as follows: R=(CH2) n or Among them, n=3-16.

3. The method for synthesizing a diprimary amine ionic flame retardant according to claim 2, characterized in that: The reaction is carried out in an alcohol solvent at room temperature, and a white powdery substance is precipitated after the reaction.

4. The method for synthesizing a diprimary amine ionic flame retardant according to claim 3, characterized in that: The alcohol solvent is a low-carbon alcohol solvent selected from any one of methanol, ethanol, propanol or butanol.

5. The method for synthesizing a diprimary amine ionic flame retardant according to claim 3, characterized in that: The di-primary amine compound and DOPA are dissolved in an alcohol solvent respectively, and then the DOPA liquid is added dropwise to the di-primary amine compound liquid to react.

6. The method for synthesizing a diprimary amine ionic flame retardant according to claim 3, characterized in that: The molar ratio of the diprimary amine compound to DOPA is 1-1.2:0.8-1.0; the reaction temperature is room temperature 23-30° C.; and the reaction time is 7-12 hours.

7. Use of the diprimary amine ionic flame retardant as claimed in claim 1 in the preparation of epoxy resin.

8. The use according to claim 7, characterized in that: The epoxy resin is selected from any one of glycidyl ether epoxy resin, glycidyl ester epoxy resin and glycidyl amine epoxy resin.

9. The use according to claim 8, characterized in that: After bisphenol A diglycidyl ether and the P / N / S type flame retardant are fully reacted, a curing agent is added to obtain an epoxy resin with improved performance.

10. The use according to claim 9, characterized in that: The addition amount of the diprimary amine ionic flame retardant is 0.5-10 wt %.

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