Flame-retardant epoxy resin composition as well as preparation method, application and product thereof

Abstract

The invention provides a flame-retardant epoxy resin composition as well as a preparation method, application and a product thereof, and belongs to the technical field of high polymer materials. The flame-retardant epoxy resin composition contains epoxy resin, a curing agent and inorganic nitride, the epoxy resin is synthesized from a phosphorus-containing compound and epichlorohydrin or from the phosphorus-containing compound, epichlorohydrin and a phenolic hydroxyl-containing compound through a one-step method, and under the action of a curing agent and an inorganic nitride, the heat and humidity resistance of the epoxy resin can be remarkably improved while the flame retardance of the epoxy resin is maintained, and the heat and humidity resistance of the epoxy resin is improved. And the composite material can be widely applied to prepregs, metal foil-coated laminated boards or printed circuit boards.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to a flame retardant epoxy resin composition and a preparation method, application and product thereof. Background Art

[0002] Epoxy resin (EP) can be used as coatings, casting materials, molding materials, adhesives, and laminated materials due to its good formability, adhesion, electrical properties, and mechanical properties. It is widely used in fields such as packaging materials for aircraft and large-scale integrated circuits, copper-clad laminate insulation materials, coatings for steel and wood, adhesives for mechanical and civil construction, and even coatings on the inner walls of food cans and metal anti-corrosion electrophoretic coatings.

[0003] EP is a linear thermoplastic resin that does not harden by itself. Only when its linear structure is cross-linked into a network or body structure under the action of a curing agent can it have good performance. Its performance depends largely on the curing agent. In addition, water is easily absorbed in EP, which will also cause its thermal, electrical and mechanical properties to deteriorate, thereby limiting its use; and EP materials that have absorbed water molecules will experience welding cracks due to the vaporization and expansion of water molecules. Therefore, when EP is used in electronic packaging and other materials, it is required to have the advantages of high purity, low shrinkage, excellent heat resistance, low moisture absorption and fast curing.

[0004] The biggest disadvantage of epoxy resin is its flammability. Phosphorus is an element that easily forms compounds. POC bonds or PC bonds have good stability. Phosphorus-based flame retardant systems can increase the carbonization rate of materials, especially oxygen-containing polymers, during combustion. The resulting carbon layer is resistant to oxidation. At the same time, phosphoric acid can cover the carbon layer to prevent ignition.

[0005] Chinese invention patent application CN110105539A discloses an application of a phosphorus-containing compound in the one-step synthesis of a flame-retardant epoxy resin, a flame-retardant epoxy resin, a preparation method and an application thereof. The phosphorus-containing compound and epichlorohydrin are synthesized in a one-step process, and the phosphorus-containing compound can be located not only at the end group of the flame-retardant epoxy resin, but also on the main chain of the flame-retardant epoxy resin, so that the flame-retardant epoxy resin not only has excellent flame retardant properties, but also has excellent moisture and heat resistance stability, thereby being able to effectively meet the high-frequency and high-speed use requirements of existing electronic products.

[0006] However, as the demand for high-speed and multifunctional information processing in electronic products increases, the frequency of application also increases, and the requirements for flame retardancy and moisture and heat stability of resins also increase. Therefore, it is necessary to further study its curing agent and auxiliary agent system to improve its comprehensive performance. Summary of the invention

[0007] The inventors of the present invention have found that the flame-retardant epoxy resin synthesized from a phosphorus-containing compound and epichlorohydrin by a one-step process has further improved moisture and heat resistance while maintaining flame retardancy after being compounded with a suitable curing agent and a modification aid, especially an inorganic nitride. Therefore, the obtained flame-retardant epoxy resin composition has a wider application in prepregs, metal foil-clad laminates or printed circuit boards.

[0008] One of the technical solutions of the present invention is:

[0009] Provided is a flame retardant epoxy resin composition, which contains: an epoxy resin, a curing agent and an inorganic nitride; the epoxy resin is synthesized from a phosphorus-containing compound and epichlorohydrin by a one-step method, and the phosphorus-containing compound has the following structure:

[0010]

[0011] Among them, R1, R2, R3 and R4 are independently selected from hydrogen atoms, aliphatic hydrocarbons with 1-20 carbon atoms or their derivatives, alicyclic hydrocarbons with 3-20 carbon atoms or their derivatives, unsaturated aliphatic hydrocarbons with 2-20 carbon atoms or their derivatives, and aromatic hydrocarbons with 6-20 carbon atoms or their derivatives.

[0012] The P in the phosphorus-containing compound in the phosphorus-containing flame-retardant epoxy resin selected by the present invention is wrapped by a condensed ring structure, which provides the composition with lower water absorption and higher structural stability; in addition, the flame-retardant epoxy resin has a higher P content, which also provides the composition with higher flame retardant properties. It is found in experiments that when it is used with a curing agent and an auxiliary agent, especially when an inorganic nitride is used as an auxiliary agent, it can improve moisture resistance and heat resistance while ensuring its own flame retardant properties.

[0013] In some preferred embodiments of the present invention, the phosphorus content in the epoxy resin is 0.1-7.2 wt %; and the epoxy equivalent of the flame retardant epoxy resin is 180-2000 g / mol.

[0014] Typically, but not limiting, the phosphorus content in the flame retardant epoxy resin is 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt% or 7.2 wt%.

[0015] Typically, but not limiting, the epoxy equivalent weight in the flame retardant epoxy resin is 180 g / mol, 200 g / mol, 250 g / mol, 300 g / mol, 400 g / mol, 500 g / mol, 800 g / mol, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol or 2000 g / mol.

[0016] Specifically, the epoxy resin of the present invention is prepared by the technical solution disclosed in patent application CN201910499212.1, and is synthesized by a one-step method from a phosphorus-containing compound (structure as shown in Formula I) and epichlorohydrin. In some specific embodiments of the present invention, the phosphorus-containing compound, epichlorohydrin and an optional hydroxyl-containing phenol compound are uniformly mixed in a solvent, and a one-step polymerization reaction is carried out under alkaline conditions to obtain the obtained product; wherein the polymerization reaction temperature is 50-100°C, and the pH value of the reaction system is 8-14.

[0017] Furthermore, the flame retardant epoxy resin composition contains, by weight, 50-200 parts of epoxy resin, 10-60 parts of curing agent and 100-200 parts of inorganic nitride.

[0018] Preferably, the flame retardant epoxy resin composition contains, by weight, 80-100 parts of epoxy resin, 20-40 parts of curing agent and 120-150 parts of inorganic nitride.

[0019] Furthermore, the curing agent is an amine curing agent, an amide curing agent and / or an imidazole curing agent.

[0020] Preferably, the curing agent is an amine curing agent or an imidazole curing agent.

[0021] More preferably, the weight ratio of the amine curing agent to the imidazole curing agent is 1-5:0.05-0.2.

[0022] Typically but not limiting, the weight ratio of the amine curing agent to the imidazole curing agent is 1:0.2, 1:0.1, 1:0.05, 2:0.05, 3:0.05, 4:0.05, 5:0.05.

[0023] Furthermore, the amine curing agent is specifically selected from one or more of meta-phenylenediamine, meta-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, meta-aminomethylamine, phenylenediamine and methylenebisphenylenediamine.

[0024] Furthermore, the amide curing agent is selected from polyamide 650 and / or polyamide 651.

[0025] Furthermore, the imidazole curing agent is specifically selected from one or more of imidazole, 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole.

[0026] Furthermore, the inorganic nitride is selected from one or more of silicon nitride, aluminum nitride and boron nitride.

[0027] Furthermore, the flame retardant epoxy resin composition further contains: a lanthanide compound.

[0028] Preferably, the lanthanide compound is specifically selected from one or more of lanthanum chloride, lanthanum oxide or lanthanum hydroxide.

[0029] More preferably, the mass ratio of the lanthanide compound to the inorganic nitride is 0.1-5:1; further preferably 0.1-1:1.

[0030] Typically, but not limiting, the mass ratio of the lanthanide compound to the inorganic nitride is 0.1:1, 0.2:1, 0.5:1, 0.8:1, 1:1, 2:1, 3:1, 4:1, 5:1.

[0031] The second technical solution of the present invention is:

[0032] A method for preparing any of the flame retardant epoxy resin compositions described above is provided, comprising the following steps:

[0033] (1) dissolving epoxy resin, curing agent and inorganic nitride in a solvent;

[0034] (2) With or without adding lanthanide compounds, the product is obtained by melting.

[0035] The third technical solution of the present invention is:

[0036] Provided is the use of any of the above-mentioned flame-retardant epoxy resin compositions or a flame-retardant epoxy resin composition prepared by any of the above-mentioned preparation methods in prepregs, metal foil-clad laminates or printed circuit boards.

[0037] The fourth technical solution of the present invention is:

[0038] Provided is a product comprising any of the flame retardant epoxy resin compositions described above or a flame retardant epoxy resin composition prepared by any of the preparation methods described above, wherein the product is any of a prepreg, a metal foil-clad laminate or a printed circuit board.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The composition of the present invention is simple in composition and adopts phosphorus-containing epoxy resin, which itself has good flame retardancy and moisture-heat resistance. By combining the auxiliary nitride with the curing agent, the flame-retardant epoxy resin composition obtained has better comprehensive performance than other auxiliary agents;

[0041] (2) Further, by selecting a curing agent, in particular, using an imidazole curing agent, which acts as a curing agent on the one hand and a curing accelerator for an amine curing agent on the other hand, when the amount of the imidazole curing agent is extremely low, the curing time of the composition can be significantly improved to obtain a cured product with less ionic impurities and excellent moisture and heat resistance, which has a significant effect on improving the performance of the composition;

[0042] (3) The inventors of the present invention have also found that adding rare earth compounds, especially lanthanide compounds, to the system can further improve the moisture and heat resistance of the composition;

[0043] (4) The epoxy resin composition prepared by the present invention has an epoxy curing system with good flame retardant properties and other excellent properties of epoxy resin, such as moisture and heat resistance, and can be widely used in prepregs, laminates, metal foil-clad laminates or printed circuit boards. It also has excellent dielectric properties and has greater application value in printed circuit boards. DETAILED DESCRIPTION

[0044] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, conventional conditions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0045] The flame retardant epoxy resin A used in the embodiment of the present invention is prepared by the method of Example 2 of patent application CN201910499212.1; wherein the epoxy equivalent of the epoxy resin is 260 g / mol and the phosphorus content is 7.0 wt%. The flame retardant epoxy resin B is prepared by the method of Comparative Example 1 of patent application CN201910499212.1; wherein the epoxy equivalent of the epoxy resin is 310 g / mol and the phosphorus content is 2.5 wt%.

[0046] Examples 1-10

[0047] The flame retardant epoxy resin prepreg and laminate were prepared according to the formula in Table 1. The specific steps are as follows:

[0048] (1) Weighing each component according to the formula in Table 1, and dissolving them in a mixed solvent of N-methylpyrrolidone and cyclohexanone (1:1 V / V) to form a varnish;

[0049] (2) impregnating a 125 μm thick glass fiber cloth prepreg (model: 7628) with the varnish, heating to 170° C., and drying for 5 minutes to obtain prepregs 1-10;

[0050] (3) Three layers of the impregnated parts were overlapped, and a 20 μm thick copper foil (purchased from Kunshan Luzhifa Electronic Technology Co., Ltd.) was added to the upper and lower surfaces of the three overlapping parts. The laminates 1-10 were cured at 180°C for 2 hours using a vacuum hot press.

[0051] Table 1 Flame retardant epoxy resin composition formula

[0052]

[0053]

[0054] The test results of the properties of the prepregs and laminates prepared in the above examples are shown in Table 2.

[0055] Table 2 Performance indexes of prepreg 1-10 and laminate 1-10

[0056]

[0057] Description: (1) Flame retardancy: UL94 evaluation standard for flammability test of plastic materials is adopted; (2) Glass transition temperature: Differential scanning calorimeter is adopted, and the test conditions are room temperature - 240°C, and the heating rate is 20°C / min; (3) Peel strength: Measured according to JIS C 6481 specification; (4) Moisture and heat resistance: After absorbing moisture in the steam phase at 121°C and 100% humidity for 6 hours, observe its quality changes, bubbles and peeling.

[0058] Comparative Example 1

[0059] Patent application CN201910499212.1 Example 2 prepared 100g of flame-retardant epoxy resin, 180g of phenolic epoxy resin (model NPPN638, produced by Taiwan Nan Ya Plastics), 120g of silica and dicy (chemical name is dicyandiamide, CAS: 461-58-5, Ningxia Dayong Industrial Group Co., Ltd.), wherein the amount of dicy is 0.6eq of the total amount of flame-retardant epoxy resin and phenolic epoxy resin, and a prepreg 11 and a laminate 11 are prepared according to the preparation method of Example 1.

[0060] Comparative Example 2

[0061] Compared with composition 3, the only difference is that epoxy resin A is replaced by an equal amount of epoxy resin B. A prepreg 12 and a laminate 12 are prepared according to the preparation method of Example 1.

[0062] Comparative Example 3

[0063] Compared with composition 3, the only difference is that silicon nitride is replaced by an equal amount of silicon oxide. A prepreg 13 and a laminate 13 are prepared according to the preparation method of Example 1.

[0064] Comparative Example 4

[0065] Compared with composition 8, the only difference is that cerium oxide is used in place of lanthanum oxide in an equal amount. A prepreg 14 and a laminate 14 are prepared according to the preparation method of Example 1.

[0066] Comparative Example 5

[0067] Compared with composition 8, the only difference is the different amounts of the components in the composition, specifically: 100 parts of epoxy resin, 180 parts of diaminodiphenylmethane, 120 parts of silicon carbide, 168 parts of lanthanum oxide (the same ratio of flame retardant epoxy resin, phenolic epoxy resin, silica and dicy in comparative example 1). Prepreg 15 and laminate 15 are prepared according to the preparation method of Example 1.

[0068] Table 3 Performance indexes of prepregs 3, 8, 11-15 and laminates 3, 8, 11-15

[0069]

[0070]

[0071] Note: The relevant performance testing methods are the same as those in Table 2.

[0072] It can be seen from the above table that the composition obtained by the phosphorus-containing flame-retardant epoxy resin of the present invention under the action of the curing agent and the auxiliary inorganic nitride has good flame retardancy, and the moisture and heat resistance and the bonding strength with the copper foil are improved; further through the selection of the type / dosage optimization of the curing agent, the introduction of lanthanide compounds and the adjustment of the dosage, the moisture and heat resistance is further improved, and the comprehensive performance is excellent.

[0073] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A flame retardant epoxy resin composition, characterized in that: The flame retardant epoxy resin composition contains: epoxy resin, curing agent and inorganic nitride; the epoxy resin is synthesized from a phosphorus-containing compound and epichlorohydrin or from a phosphorus-containing compound, epichlorohydrin and a phenolic hydroxyl-containing compound by a one-step method, and the structure of the phosphorus-containing compound is as follows: Among them, R1, R2, R3 and R4 are independently selected from hydrogen atoms, aliphatic hydrocarbons with 1-20 carbon atoms or their derivatives, alicyclic hydrocarbons with 3-20 carbon atoms or their derivatives, unsaturated aliphatic hydrocarbons with 2-20 carbon atoms or their derivatives, and aromatic hydrocarbons with 6-20 carbon atoms or their derivatives.

2. The flame retardant epoxy resin composition according to claim 1, characterized in that: The flame retardant epoxy resin composition contains, by weight: 50-200 parts of epoxy resin, 10-60 parts of curing agent and 100-200 parts of inorganic nitride; Preferably, the flame retardant epoxy resin composition contains, by weight, 80-100 parts of epoxy resin, 20-40 parts of curing agent and 120-150 parts of inorganic nitride.

3. The flame retardant epoxy resin composition according to claim 1, characterized in that: The curing agent is an amine curing agent, an amide curing agent and / or an imidazole curing agent; preferably, the curing agent is an amine curing agent and an imidazole curing agent; further preferably, the weight ratio of the amine curing agent to the imidazole curing agent is 1-5:0.05-0.

2.

4. The flame retardant epoxy resin composition according to claim 3, characterized in that: The amine curing agent is specifically selected from one or more of m-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, m-aminomethylamine, phenylenediamine and methylenebisphenylenediamine; The amide curing agent is selected from polyamide 650 and / or polyamide 651; The imidazole curing agent is specifically selected from one or more of imidazole, 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole.

5. The flame retardant epoxy resin composition according to claim 1, characterized in that: The inorganic nitride is selected from one or more of silicon nitride, aluminum nitride and boron nitride.

6. The flame retardant epoxy resin composition according to any one of claims 1 to 5, characterized in that: The flame retardant epoxy resin composition further contains: a lanthanum compound; the lanthanum compound is specifically selected from one or more of lanthanum chloride, lanthanum oxide or lanthanum hydroxide.

7. The flame retardant epoxy resin composition according to claim 6, characterized in that: The mass ratio of the lanthanide compound to the inorganic nitride is 0.1-5:1, preferably 0.1-1:

1.

8. The method for preparing the flame retardant epoxy resin composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) dissolving epoxy resin, curing agent and inorganic nitride in a solvent; (2) With or without adding lanthanide compounds, the product is obtained by melting.

9. Use of the flame retardant epoxy resin composition according to any one of claims 1 to 7 or the flame retardant epoxy resin composition prepared by the preparation method according to claim 8 in prepregs, metal foil-clad laminates or printed circuit boards.

10. A product comprising the flame retardant epoxy resin composition according to any one of claims 1 to 7 or the flame retardant epoxy resin composition prepared by the preparation method according to claim 8, characterized in that: The product is any one of a prepreg, a metal foil-clad laminate or a printed circuit board.

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