Flame-retardant composition and flame-retardant epoxy resin

Abstract

The invention relates to a flame-retardant composition and flame-retardant epoxy resin, and belongs to the technical field of epoxy resin. The flame-retardant composition disclosed by the invention consists of a composite flame retardant, a charring agent and a charring synergist, the mass ratio of the composite flame retardant to the charring agent to the charring synergist is (4-10): (1.5-4.5): 1; the char forming synergist is Michelene; the composite flame retardant is composed of a phosphorus-nitrogen flame retardant and a nitrogen flame retardant, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen flame retardant is (1-3): 1. According to the flame-retardant epoxy resin and the preparation method thereof, the MXene is used as the charring synergist, the composite flame retardant and the charring agent are combined to form the flame-retardant composition, the flame-retardant composition is combined with the epoxy resin to prepare the flame-retardant epoxy resin, the vertical combustion performance of the flame-retardant epoxy resin reaches UL94V-0, the use safety of the epoxy resin in an extreme environment is improved, and the flame-retardant epoxy resin has important theoretical and industrial values.

Description

Technical Field

[0001] The present invention relates to a flame - retardant composition and a flame - retardant epoxy resin, belonging to the technical field of epoxy resins. Background Art

[0002] Epoxy resin (EP) is a kind of polymer. Due to its excellent mechanical properties, electrical properties, bonding strength, corrosion resistance, easy processability and other advantages, it has been widely used in fields such as construction, coatings and aerospace. However, as a polymer material, epoxy resin has the defect of being easy to burn, and a large amount of toxic and harmful gases will be generated during its combustion process, which severely limits the application scope of epoxy resin. Therefore, it is necessary to carry out flame - retardant modification treatment on epoxy resin to improve the safety of the material during use.

[0003] The flame - retardant modification methods of epoxy resin mainly include additive flame - retardant modification and reactive flame - retardant modification. The additive flame - retardant modification method has advantages such as simple operation and easy industrial application. Flame - retardants for epoxy resin include inorganic flame - retardants, halogen - containing flame - retardants, organophosphorus flame - retardants, etc. However, when in use, inorganic flame - retardants have problems such as excessive addition amount and poor flame - retardant effect; halogen - containing flame - retardants have problems such as releasing a large amount of highly toxic and carcinogenic substances during combustion, which seriously endanger people's physical health and living environment. Therefore, in recent years, organophosphorus flame - retardants have become a research hotspot in epoxy resin flame - retardants. However, organophosphorus flame - retardants have problems such as single composition and the flame - retardant effect not meeting expectations. Therefore, developing a flame - retardant composition with good flame - retardant effect and simple preparation method is an urgent technical problem to be solved. Summary of the Invention

[0004] The first object of the present invention is to provide a flame - retardant composition to solve the problem of poor flame - retardant effect in the prior art.

[0005] The second object of the present invention is to provide a flame - retardant epoxy resin including the flame - retardant composition. After testing, the flame - retardant performance of the flame - retardant epoxy resin provided by the present invention can reach the UL94 V - 0 grade.

[0006] In order to achieve the above objects, the technical solution of the flame - retardant composition in the present invention is as follows:

[0007] A flame - retardant composition is composed of a composite flame - retardant, a char - forming agent and a char - forming synergist; the mass ratio of the composite flame - retardant: char - forming agent: char - forming synergist is (4 - 10):(1.5 - 4.5):1; the char - forming synergist is MXene; the composite flame - retardant is composed of a phosphorus - nitrogen flame - retardant and a nitrogen - based flame - retardant, and the mass ratio of the phosphorus - nitrogen flame - retardant to the nitrogen - based flame - retardant is (1 - 3):1.

[0008] The beneficial effects of the above technical solution are as follows: The flame retardant composition of the present invention is a pioneering invention. The flame retardant composition of the present invention is composed of a phosphorus-nitrogen flame retardant, a nitrogen-based flame retardant, a charring agent, and a charring synergist. Among them, the phosphorus-nitrogen flame retardant and the nitrogen-based flame retardant play an intumescent flame retardant effect; the charring agent promotes the formation of stable carbon during combustion; the charring synergist plays a role in promoting charring and physical heat insulation. The three substances act synergistically to rapidly form an intumescent carbonaceous layer covering the surface of the material during combustion, which well isolates air and heat conduction, protects the polymer, and plays a flame retardant role.

[0009] As a further improvement, the MXene is at least one of molybdenum carbide MXene, titanium carbide MXene, tantalum carbide MXene, and titanium nitride MXene.

[0010] The beneficial effects of the above technical solution are as follows: The selected charring synergist of the present invention is two-dimensional MXene (Chinese name: Mikeene). This two-dimensional graphene-like MXene material has advantages such as a high BET specific surface area and excellent high-temperature resistance (ceramic material). It can play a role in physical heat insulation and assisting charring during the combustion process of polymer materials, thereby improving the flame retardant performance of polymer materials.

[0011] As a further improvement, the phosphorus-nitrogen flame retardant is a polyphosphate compound; the nitrogen-based flame retardant is a melamine salt compound.

[0012] The beneficial effects of the above technical solution are as follows: Polyphosphates can provide a phosphorus source, and can form viscous compounds such as pyrophosphoric acid and polyphosphoric acid during combustion, promoting the dehydration of organic substances and the role of covering and isolating air, thereby achieving the purpose of flame retardancy; melamine can release nitrogen during combustion, and nitrogen has the effects of non-combustion and diluting the air concentration, thereby playing a flame retardant role.

[0013] As a further improvement, the polyphosphate compound is any one of ammonium polyphosphate, guanidine phosphate, condensed guanidine phosphate, piperazine pyrophosphate, and melamine polyphosphate; the melamine salt compound is any one of melamine, melamine cyanurate, melamine borate, dicyandiamide, guanidine carbonate, and guanidine sulfamate.

[0014] The beneficial effects of the above technical solution are as follows: The above substances are all common flame retardants in phosphorus-nitrogen flame retardants and nitrogen-based flame retardants, with a wide range of sources and easy availability, and are compatible with the selected charring agent and charring synergist, and can achieve good flame retardant effects.

[0015] Preferably, the polyphosphate compound is melamine polyphosphate; the melamine salt compound is melamine cyanurate.

[0016] As a further improvement, the charring agent is a polyol organic substance.

[0017] The beneficial effects of the above technical solution are as follows: The polyol charring agent is prone to dehydration to form a carbon layer under the action of the dehydrating agent, which plays a role in isolating air.

[0018] As a further improvement, the polyol organic compound is dipentaerythritol or pentaerythritol.

[0019] Preferably, the polyol organic compound is dipentaerythritol.

[0020] In order to enhance the ability of the epoxy flame-retardant resin to form a carbon layer, preferably, the polyol organic compound is pentaerythritol or dipentaerythritol.

[0021] To achieve the above object, a technical solution of a flame-retardant epoxy resin including a flame-retardant composition in the present invention is as follows:

[0022] A flame-retardant epoxy resin including a flame-retardant composition.

[0023] The beneficial effects of the above technical solution are as follows: The flame-retardant epoxy resin of the present invention adds a flame-retardant composition including a phosphorus-nitrogen flame retardant, a nitrogen-based flame retardant, a charring agent, and a charring synergist to the epoxy resin. The flame-retardant performance can reach the UL94 V-0 grade, enabling it to be used for floor coatings in places such as garages, factories, and hospitals, improving the flame-retardant performance of the epoxy resin and expanding its application range.

[0024] As a further improvement, the mass ratio of the flame-retardant composition to the epoxy resin in the flame-retardant epoxy resin is 1:(2.5 - 3). BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the thermogravimetric curve graph of the flame-retardant epoxy resins of Examples 4 - 6 in Experimental Example 1 of the present invention;

[0026] Figure 2 It is the tensile strength test result graph of the flame-retardant epoxy resins of Examples 4 - 6 in Experimental Example 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In the prior art, the flame retardants for epoxy resins are mainly inorganic flame retardants, halogenated flame retardants, and organophosphorus flame retardants. Among them, inorganic flame retardants have the problems of excessive addition amount and poor flame retardant effect; halogenated flame retardants have the problem of releasing a large amount of highly toxic and carcinogenic substances during combustion, seriously endangering people's physical health and living environment; organophosphorus flame retardants have problems such as single composition and inability to achieve the expected flame retardant effect. In view of this situation, the present invention provides a flame retardant composition composed of a composite flame retardant, a charring agent, and a charring synergist. Among them, the phosphorus-nitrogen flame retardant and the nitrogen-based flame retardant play an intumescent flame retardant effect; the charring agent promotes the formation of stable carbon during combustion; the charring synergist plays a role in promoting charring and physical heat insulation. The three substances act synergistically to rapidly form an intumescent carbonaceous layer covering the surface of the material during combustion, effectively isolating air and heat conduction, protecting the polymer, and playing a flame retardant role.

[0028] A flame retardant composition is composed of a composite flame retardant, a charring agent, and a charring synergist; the mass ratio of the composite flame retardant: charring agent: charring synergist is (4-10):(0.75-4.5):1; the charring synergist is MXene; the composite flame retardant is composed of a phosphorus-nitrogen flame retardant and a nitrogen-based flame retardant, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is (1-3):1.

[0029] Preferably, the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is (1-3):1.

[0030] Preferably, the MXene is at least one of molybdenum carbide MXene, titanium carbide MXene, tantalum carbide MXene, and titanium nitride MXene.

[0031] Preferably, the phosphorus-nitrogen flame retardant is a polyphosphate compound; the nitrogen-based flame retardant is a melamine salt compound.

[0032] Preferably, the polyphosphate compound is any one of ammonium polyphosphate, guanidine phosphate, condensed guanidine phosphate, piperazine pyrophosphate, and melamine polyphosphate; the melamine salt compound is any one of melamine, melamine cyanurate, melamine borate, dicyandiamide, guanidine carbonate, and guanidine sulfamate.

[0033] Preferably, the charring agent is a polyol organic compound.

[0034] More preferably, the polyol organic compound is dipentaerythritol or pentaerythritol.

[0035] Preferably, the polyol organic compound is dipentaerythritol.

[0036] A flame retardant epoxy resin comprising the flame retardant composition.

[0037] Preferably, the mass ratio of the flame retardant composition to the epoxy resin in the flame retardant epoxy resin is 1:(2.5 - 3).

[0038] The following further describes the present invention in combination with specific embodiments. It should be noted that, on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment. The equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are conventional methods in the art unless otherwise specified.

[0039] The epoxy resin used in the following examples is epoxy resin E-44, and the charring synergist MXene is self-made in the laboratory Ti 3 C 2 , and the specific preparation method is as follows:

[0040] Preparation method: Mix lithium fluoride and hydrochloric acid to obtain an etching solution, and then add Ti 3 AlC 2 to the above etching solution for etching, then obtain the MXene solution by shaking the solution, and then filter and dry to obtain MXene.

[0041] I. Specific embodiments of a flame retardant composition of the present invention:

[0042] Example 1

[0043] The flame retardant composition of this example is composed of a composite flame retardant, a charring agent, and a charring synergist; the mass ratio of the composite flame retardant: charring agent: charring synergist is 8:3:1; the charring synergist is MXene; the composite flame retardant is composed of melamine polyphosphate and melamine cyanurate, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is 1:1; the charring agent is dipentaerythritol.

[0044] Example 2

[0045] The flame retardant composition of this example is composed of a composite flame retardant, a charring agent, and a charring synergist; the mass ratio of the composite flame retardant: charring agent: charring synergist is 10:4.5:1; the charring synergist is MXene; the composite flame retardant is composed of melamine polyphosphate and melamine cyanurate, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is 2:1; the charring agent is dipentaerythritol.

[0046] Example 3

[0047] The flame-retardant composition of this embodiment is composed of a composite flame retardant, a charring agent, and a charring synergist; the mass ratio of the composite flame retardant: charring agent: charring synergist is 4:1.5:1; the charring synergist is MXene; the composite flame retardant is composed of melamine polyphosphate and melamine cyanurate, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is 3:1; the charring agent is dipentaerythritol.

[0048] II. Specific embodiments of a flame-retardant epoxy resin of the present invention:

[0049] Example 4

[0050] The flame-retardant epoxy resin of this embodiment includes the flame-retardant composition in Example 1 and epoxy resin, and the mass ratio of the flame-retardant composition to the epoxy resin is 1:3. The specific preparation method is as follows:

[0051] (1) Place the composite flame retardant, charring agent, and charring synergist in an oven at 105 °C and dry for 12 h;

[0052] (2) Place the dried composite flame retardant, charring agent, and charring synergist in an agate mortar, grind them, and sieve them with a 400-mesh sieve;

[0053] (3) Place the composite flame retardant, charring agent, and charring synergist that have passed through the sieve into a high-speed centrifuge and mix them at high speed for 30 min to obtain a highly dispersed additive flame retardant;

[0054] (4) Add the additive flame retardant obtained in step (3) and the curing agent triethylenetetramine in a proportion (8%) to the epoxy resin, and place the above materials in a vacuum degassing mixer for degassing and stirring for 30 min to obtain a material with few matrix bubbles and uniform mixing;

[0055] (5) Place the material obtained in step (4) in a stainless-steel standard mold coated with a mold release agent, cure it at room temperature for 3 h, and then cure it in an oven at 85 °C for 3 h to obtain flame-retardant epoxy resin 1. After testing, the vertical burning rating of flame-retardant epoxy resin 1 reaches UL94 V-0, and the limiting oxygen index is 21.4%.

[0056] Example 5

[0057] The flame-retardant epoxy resin of this embodiment includes the flame-retardant composition in Example 2 and epoxy resin, and the mass ratio of the flame-retardant composition to the epoxy resin is 1:2.5. The specific preparation method is as follows:

[0058] (1) Place the composite flame retardant, charring agent, and charring synergist in an oven at 105 °C and dry for 12 h;

[0059] (2) Place the dried composite flame retardant, charring agent, and charring synergist in an agate mortar for grinding, and sieve them through a 400-mesh sieve;

[0060] (3) Place the sieved composite flame retardant, charring agent, and charring synergist in a high-speed centrifuge for high-speed mixing for 30 min to obtain a highly dispersed additive flame retardant;

[0061] (4) Add the additive flame retardant obtained in step (3) and the curing agent triethylenetetramine to the epoxy resin in a ratio of 8%, and place the above materials in a vacuum degassing mixer for degassing and stirring for 30 min to obtain a material with few matrix bubbles and uniform mixing;

[0062] (5) Place the material obtained in step (4) in a stainless-steel standard mold coated with a release agent, cure it at room temperature for 3 h, and then cure it in an oven at 85 °C for 3 h to obtain flame-retardant epoxy resin 2. After testing, the vertical burning rating of flame-retardant epoxy resin 2 reaches UL94 V-0, and the limiting oxygen index is 22.6%.

[0063] Example 6

[0064] The flame-retardant epoxy resin of this example includes the flame-retardant composition and epoxy resin in Example 3, and the mass ratio of the flame-retardant composition to the epoxy resin is 1:3. The specific preparation method is as follows:

[0065] (1) Place the composite flame retardant, charring agent, and charring synergist in an oven at 105 °C for drying for 12 h;

[0066] (2) Place the dried composite flame retardant, charring agent, and charring synergist in an agate mortar for grinding, and sieve them through a 400-mesh sieve;

[0067] (3) Place the sieved composite flame retardant, charring agent, and charring synergist in a high-speed centrifuge for high-speed mixing for 30 min to obtain a highly dispersed additive flame retardant;

[0068] (4) Add the additive flame retardant obtained in step (3) and the curing agent triethylenetetramine to the epoxy resin in a ratio of 8%, and place the above materials in a vacuum degassing mixer for degassing and stirring for 30 min to obtain a material with few matrix bubbles and uniform mixing;

[0069] (5) Place the material obtained in step (4) in a stainless-steel standard mold coated with a release agent, cure it at room temperature for 3 h, and then cure it in an oven at 85 °C for 3 h to obtain flame-retardant epoxy resin 3. After testing, the vertical burning rating of flame-retardant epoxy resin 3 reaches UL94 V-0, and the limiting oxygen index is 23.5%.

[0070] III. Experimental Examples

[0071] Experimental Example 1

[0072] In this experimental example, thermogravimetric analysis was performed on the flame-retardant epoxy resins of Examples 4 to 6, and the results are as Figure 1 shown.

[0073] Figure 1 Figure 11 shows the thermogravimetric curves of the flame-retardant epoxy resins of Examples 4 to 6. It can be seen from the figure that the initial thermal decomposition temperature of the pure epoxy resin is 300 °C, and the char residue at 700 °C is about 14%. After adding the composite flame retardant, charring agent, and charring synergist, the initial decomposition temperature of the flame-retardant epoxy resin decreases to about 240 °C, indicating that the flame retardant decomposes first during heating to play a flame-retardant role; the char residue of the flame-retardant epoxy resin at 700 °C increases to more than 20%, indicating that the addition of the composite flame retardant, charring agent, and charring synergist helps the formation of an insulating carbon layer.

[0074] Experimental Example 2

[0075] In this example, the tensile strength of the flame-retardant epoxy resins of Examples 4 to 6 was tested, and the results Figure 2 are as

[0076] Figure 2 Figure 23 shows the test results of the tensile strength of the flame-retardant epoxy resins of Examples 4 to 6. It can be seen from the figure that the tensile strength of the pure epoxy resin is 73.636 Mpa (the test standard is ASTM D638-14). After adding the composite flame retardant, charring agent, and charring synergist, the tensile strength of the flame-retardant epoxy resin decreases to a certain extent, but it is still above 30 Mpa, which can meet the use requirements.

[0077] As described above, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. The patent protection scope of the present invention is subject to the claims. All equivalent structural changes made by using the description and drawings of the present invention should, by the same token, be included in the protection scope of the present invention.

Claims

1. A flame retardant composition, characterized in that: It is composed of a composite flame retardant, a charring agent and a charring synergist; the mass ratio of the composite flame retardant: charring agent: charring synergist is (4-10): (1.5-4.5): 1; the charring synergist is michalene; the composite flame retardant is composed of a phosphorus-nitrogen flame retardant and a nitrogen-based flame retardant, and the mass ratio of the phosphorus-nitrogen flame retardant to the nitrogen-based flame retardant is (1-3):

1.

2. The flame retardant composition according to claim 1, characterized in that: The michelene is at least one of molybdenum carbide michelene, titanium carbide michelene, tantalum carbide michelene and titanium nitride michelene.

3. The flame retardant composition according to claim 1, characterized in that: The phosphorus-nitrogen flame retardant is a polyphosphate compound; the nitrogen-based flame retardant is a melamine salt compound.

4. The flame retardant composition according to claim 3, characterized in that: The polyphosphate compound is any one of ammonium polyphosphate, guanidine phosphate, condensed guanidine phosphate, piperazine pyrophosphate, and melamine polyphosphate; the melamine salt compound is any one of melamine, melamine cyanurate, melamine borate, dicyandiamide, guanidine carbonate, and guanidine sulfamate.

5. The flame retardant composition according to claim 1, characterized in that: The carbon-forming agent is a polyol organic substance.

6. The flame retardant composition according to claim 5, characterized in that: The polyol organic matter is dipentaerythritol and pentaerythritol.

7. A flame retardant epoxy resin comprising the flame retardant composition according to any one of claims 1 to 6.

8. The flame retardant epoxy resin according to claim 7, characterized in that: The mass ratio of the flame retardant composition to the epoxy resin in the flame retardant epoxy resin is 1:(2.5-3).

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