Phosphorus-nitrogen flame retardant, flame-retardant epoxy resin and preparation method of flame-retardant epoxy resin

Abstract

The invention discloses a phosphorus-nitrogen flame retardant, the structural general formula of which is # imgabs0 #. The invention also discloses a preparation method of the phosphorus-nitrogen flame retardant, flame-retardant epoxy resin using the phosphorus-nitrogen flame retardant and a preparation method of the flame-retardant epoxy resin. The phosphorus-nitrogen flame retardant is composite phosphorus-nitrogen-aluminum and contains halogen, the flame retardant is high in flame retardant efficiency and good in flame retardant effect, a high flame retardant grade can be achieved when the addition amount of the flame retardant is low, and degradation of the mechanical property of a matrix caused by addition of a large amount of flame retardant is avoided. In addition, the flame retardant provided by the invention has large molecular weight, the molecular weight is about 1500 according to preliminary determination, and the flame retardant is used as an additive flame retardant, and as the flame retardant is an epichlorohydrin structure derivative, the flame retardant has better compatibility with epoxy resin, the molecular weight is larger than that of a conventional flame retardant, the flame retardant is not easy to migrate in an epoxy system, and the heat resistance is good.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardants, and in particular to a phosphorus-nitrogen flame retardant, a flame-retardant epoxy resin and a preparation method thereof. Background Art

[0002] Epoxy resin is one of the most widely used thermosetting resins. Epoxy resin is generally obtained by reacting phenolic compounds with epichlorohydrin to obtain a resin with an epoxy group as the terminal group. Among them, bisphenol A type resin accounts for more than 85%. With the development of the electronic and electrical industry, epoxy resin has been widely used in electronic circuit substrates and power insulation boards because of its good heat resistance, dimensional stability, modulus and rigidity, as well as excellent adhesion to metal. The oxygen index of epoxy resin is 19.8. After ignition, it can burn in the air and burn quickly. Therefore, in order to improve the flame retardant properties of epoxy resin, adding flame retardants to epoxy resin is a common means to improve the oxygen index of epoxy resin. However, the flame retardant efficiency of the currently added flame retardant is often unsatisfactory. On the one hand, in order to obtain the ideal flame retardant effect, a large amount of flame retardant needs to be added. On the other hand, due to the compatibility problem between the flame retardant and the epoxy resin, the mechanical properties of the prepared epoxy resin are reduced, and the added flame retardant is easy to migrate, which worsens the use of the material.

[0003] There are many types of flame retardants, and phosphorus-containing compounds are considered to be one of the most effective flame retardants. They can capture active free radicals in the gas phase, prevent combustion reactions, and release less toxic substances. Therefore, phosphorus-nitrogen flame retardants are one of the most promising flame retardants at present. They are environmentally friendly, non-toxic and efficient flame retardants and one of the important research directions in the future. Most phosphorus-containing flame retardants not only play a flame retardant role by forming a protective carbon layer through the phosphoric acid catalytic matrix, but also play a flame retardant role by capturing the combustible free radicals in the gas phase through the phosphorus-containing free radical fragments. In order to improve the performance of flame retardants, phosphorus-nitrogen synergy is usually used to improve the efficiency of flame retardants. However, compared with halogen flame retardants, there are still problems of low flame retardant efficiency and large smoke release. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the prior art and to provide a phosphorus-nitrogen flame retardant, a flame-retardant epoxy resin and a preparation method thereof.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A phosphorus-nitrogen flame retardant, the general structural formula of which is:

[0007]

[0008] A preparation method of a phosphorus-nitrogen flame retardant comprises the following steps: adding phosphorus oxychloride and polyamine into a baking tray, baking at 260-450°C for reaction until no gas is generated, and cooling to room temperature to obtain an intermediate; adding the intermediate into propylene oxide, adding an aluminum reagent, heating for reaction for 12 hours, and cooling for crystallization after the reaction is completed to obtain the phosphorus-nitrogen flame retardant.

[0009] Preferably, the polyamine is one of ethylenediamine, urea, melamine, p-phenylenediamine, m-phenylenediamine, diethylenetriamine, triethylenetetramine, and hexamethylenediamine.

[0010] Preferably, the aluminum reagent is one of aluminum trichloride, aluminum silicate, ethylaluminum dichloride, and diethylaluminum chloride.

[0011] Preferably, the mass ratio of the phosphorus oxychloride, polyamine, propylene oxide and aluminum reagent is 1:0.5-2.0:1-10.0:1-1.2.

[0012] A flame retardant epoxy resin, comprising the following components in parts by weight:

[0013] 60-80 parts of solid epoxy resin;

[0014] 5-10 parts of low viscosity epoxy resin;

[0015] 10-35 parts of phosphorus-nitrogen flame retardant;

[0016] 15-20 parts of toughening agent;

[0017] 6-10 parts of curing agent;

[0018] 2-6 parts of accelerator;

[0019] 10-30 parts of water.

[0020] A method for preparing a flame retardant epoxy resin comprises the following steps:

[0021] Step 1, weighing a low-viscosity epoxy resin, a phosphorus-nitrogen flame retardant, a toughening agent and an accelerator according to a proportion, and mixing them evenly at room temperature to obtain component A;

[0022] Step 2, mixing solid epoxy resin, curing agent and water to obtain component B;

[0023] Step three, mixing component A and component B evenly to obtain the flame retardant epoxy resin.

[0024] Furthermore, the solid epoxy resin (produced by Zhejiang Hongli New Materials Co., Ltd.) is brand HongLi GH60, and the low viscosity epoxy resin (produced by Zhejiang Hongli New Materials Co., Ltd.) is one of the brands HongLi@2045, HongLi@9075, HongLi@2050, HongLi@2040, HongLi@2053, and HongLi@2075.

[0025] Furthermore, toughening agents, curing agents and accelerators are all conventional commercial reagents.

[0026] The beneficial effects of the present invention are:

[0027] 1. The flame retardant of the present invention is a composite phosphorus-nitrogen-aluminum and contains halogen. The flame retardant has high flame retardant efficiency and good flame retardant effect. It can achieve a higher flame retardant grade at a lower addition amount, avoiding the deterioration of the mechanical properties of the substrate caused by the addition of a large amount of flame retardant.

[0028] 2. The flame retardant of the present invention has a relatively large molecular weight, and the preliminary measured molecular weight is about 1500. It is used as an additive flame retardant. Since it is a derivative of epichlorohydrin structure, it has better compatibility with epoxy resin, has a larger molecular weight than conventional flame retardants, is less likely to migrate out in the epoxy system, and has good heat resistance.

[0029] 3. The preparation method of the phosphorus-nitrogen flame retardant and flame-retardant epoxy resin of the present invention is simple, easy to operate and convenient for production. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with embodiments.

[0031] Example 1

[0032] Preparation of phosphorus-nitrogen flame retardants:

[0033] In a baking tray, add phosphorus oxychloride (1.0 mol) and ethylenediamine (1.0 mol), bake at 350°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add aluminum chloride (1.0 mol), heat and react for 12 hours, and after the reaction is completed, cool and crystallize to obtain the target flame retardant ZR-1.

[0034]

[0035] Preparation of flame retardant epoxy resin:

[0036] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-1 with flame retardant properties.

[0037] Example 2

[0038] Preparation of phosphorus-nitrogen flame retardants:

[0039] In a baking tray, add phosphorus oxychloride (1.0 mol) and melamine (0.5 mol), bake at 450°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add aluminum chloride (1.0 mol), heat and react for 12 hours, and after the reaction is complete, cool and crystallize to obtain the target flame retardant ZR-2.

[0040] Flame retardant epoxy resin formula:

[0041]

[0042] Preparation of flame retardant epoxy resin:

[0043] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-2 with flame retardant properties.

[0044] Example 3

[0045] Preparation of phosphorus-nitrogen flame retardants:

[0046] In a baking tray, add phosphorus oxychloride (1.0 mol) and hexamethylenediamine (1.0 mol), bake at 260°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add aluminum chloride (1.0 mol), heat and react for 12 hours, and after the reaction is complete, cool and crystallize to obtain the target flame retardant ZR-3.

[0047] Flame retardant epoxy resin formula:

[0048]

[0049] Preparation of flame retardant epoxy resin:

[0050] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-3 with flame retardant properties.

[0051] Example 4

[0052] Preparation of phosphorus-nitrogen flame retardants:

[0053] In a baking tray, add phosphorus oxychloride (1.0 mol) and m-phenylenediamine (1.0 mol), bake at 350°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add ethyl aluminum dichloride (1.0 mol), heat and react for 12 hours, and after the reaction is completed, cool and crystallize to obtain the target flame retardant ZR-4.

[0054] Flame retardant epoxy resin formula:

[0055]

[0056] Preparation of flame retardant epoxy resin:

[0057] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-4 with flame retardant properties.

[0058] Example 5

[0059] Preparation of phosphorus-nitrogen flame retardants:

[0060] In a baking tray, add phosphorus oxychloride (1.0 mol) and diethylenetriamine (1.0 mol), bake at 350°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (6.0 mol), add aluminum chloride (1.0 mol), heat and react for 12 hours, and after the reaction is completed, cool and crystallize to obtain the target flame retardant ZR-5.

[0061] Flame retardant epoxy resin formula:

[0062]

[0063]

[0064] Preparation of flame retardant epoxy resin:

[0065] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-5 with flame retardant properties.

[0066] Example 6

[0067] Preparation of phosphorus-nitrogen flame retardants:

[0068] In a baking tray, add phosphorus oxychloride (1.0 mol) and p-phenylenediamine (1.0 mol), bake at 350°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add aluminum silicate (1.0 mol), heat and react for 12 hours, and after the reaction is completed, cool and crystallize to obtain the target flame retardant ZR-6.

[0069] Flame retardant epoxy resin formula:

[0070]

[0071]

[0072] Preparation of flame retardant epoxy resin:

[0073] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-6 with flame retardant properties.

[0074] Example 7

[0075] Preparation of phosphorus-nitrogen flame retardants:

[0076] In a baking tray, add phosphorus oxychloride (1.0 mol) and urea (2.0 mol), bake at 350°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (1.0 mol), add diethylaluminum chloride (1.2 mol), heat and react for 12 hours, and after the reaction is complete, cool and crystallize to obtain the target flame retardant ZR-7.

[0077] Flame retardant epoxy resin formula:

[0078]

[0079] Preparation of flame retardant epoxy resin:

[0080] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-7 with flame retardant properties.

[0081] Example 8

[0082] Preparation of phosphorus-nitrogen flame retardants:

[0083] In a baking tray, add phosphorus oxychloride (1.0 mol) and triethylenetetramine (1.0 mol), bake at 260°C until no gas is generated, and cool to room temperature to obtain an intermediate. Add the intermediate to propylene oxide (10.0 mol), add diethylaluminum chloride (1.0 mol), heat and react for 12 hours, and after the reaction is completed, cool and crystallize to obtain the target flame retardant ZR-8.

[0084] Flame retardant epoxy resin formula:

[0085]

[0086] Preparation of flame retardant epoxy resin:

[0087] Weigh low-viscosity epoxy resin, phosphorus-nitrogen flame retardant, toughening agent and accelerator according to proportion, mix them evenly at room temperature to obtain component A; mix solid epoxy resin, curing agent and water evenly to obtain component B; mix component A and component B evenly to obtain epoxy resin HongLi@ZRSZ-8 with flame retardant properties.

[0088] Flame retardant evaluation

[0089] According to the experimental scheme of Examples 1-8, 50 mm*150 mm specimens were prepared and subjected to Vertical Burn Test (VBT) and Limiting Oxygen Index (LOI) tests. The specific flame retardant results are shown in the following table:

[0090]

[0091] Compared with existing commercial flame retardants, when used in equal amounts, both flame retardants can reach VO level, but the oxygen index of commercial flame retardants is only about 32, while the oxygen index of the flame retardant in the best embodiment of the present invention (Example 1) reaches 39.5 and has a shorter damage length.

[0092] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A phosphorus-nitrogen flame retardant, characterized in that: Its general structural formula is, 2. A method for preparing a phosphorus-nitrogen flame retardant, characterized in that: Add phosphorus oxychloride and polyamine to a baking tray, bake at 260℃-450℃ until no gas is generated, and cool to room temperature to obtain an intermediate; add the intermediate to propylene oxide, add aluminum reagent, heat to complete the reaction, cool and crystallize to obtain the phosphorus-nitrogen flame retardant.

3. The method for preparing a phosphorus-nitrogen flame retardant according to claim 2, characterized in that: The polyamine is one of ethylenediamine, urea, melamine, p-phenylenediamine, m-phenylenediamine, diethylenetriamine, triethylenetetramine and hexamethylenediamine.

4. The method for preparing a phosphorus-nitrogen flame retardant according to claim 2, characterized in that: The aluminum reagent is one of aluminum trichloride, aluminum silicate, ethylaluminum dichloride, and diethylaluminum chloride.

5. The method for preparing a phosphorus-nitrogen flame retardant according to claim 2, characterized in that: The mass ratio of the phosphorus oxychloride, polyamine, propylene oxide and aluminum reagent is 1:0.5-2.0:1-10.0:1-1.

2.

6. A flame retardant epoxy resin, characterized in that: The following components are included in parts by weight: 60-80 parts of solid epoxy resin; 5-10 parts of low viscosity epoxy resin; 10-35 parts of phosphorus-nitrogen flame retardant; 15-20 parts of toughening agent; 6-10 parts of curing agent; 2-6 parts of accelerator; 10-30 parts of water.

7. A method for preparing a flame retardant epoxy resin, characterized in that: The following steps are included: Step 1, weighing a low-viscosity epoxy resin, a phosphorus-nitrogen flame retardant, a toughening agent and an accelerator according to a proportion, and mixing them evenly at room temperature to obtain component A; Step 2, mixing solid epoxy resin, curing agent and water to obtain component B; Step three, mixing component A and component B evenly to obtain the flame retardant epoxy resin.

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