CN111269265A - Pyrazole-rich flame retardant and preparation method thereof - Google Patents
Pyrazole-rich flame retardant and preparation method thereof Download PDFInfo
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- CN111269265A CN111269265A CN202010151059.6A CN202010151059A CN111269265A CN 111269265 A CN111269265 A CN 111269265A CN 202010151059 A CN202010151059 A CN 202010151059A CN 111269265 A CN111269265 A CN 111269265A
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- flame retardant
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
- C07F9/02—Phosphorus compounds
- C07F9/547—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom
- C07F9/6564—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom having phosphorus atoms, with or without nitrogen, oxygen, sulfur, selenium or tellurium atoms, as ring hetero atoms
- C07F9/6571—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom having phosphorus atoms, with or without nitrogen, oxygen, sulfur, selenium or tellurium atoms, as ring hetero atoms having phosphorus and oxygen atoms as the only ring hetero atoms
- C07F9/657163—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom having phosphorus atoms, with or without nitrogen, oxygen, sulfur, selenium or tellurium atoms, as ring hetero atoms having phosphorus and oxygen atoms as the only ring hetero atoms the ring phosphorus atom being bound to at least one carbon atom
- C07F9/657172—Heterocyclic compounds, e.g. containing phosphorus as a ring hetero atom having phosphorus atoms, with or without nitrogen, oxygen, sulfur, selenium or tellurium atoms, as ring hetero atoms having phosphorus and oxygen atoms as the only ring hetero atoms the ring phosphorus atom being bound to at least one carbon atom the ring phosphorus atom and one oxygen atom being part of a (thio)phosphinic acid ester: (X = O, S)
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/49—Phosphorus-containing compounds
- C08K5/51—Phosphorus bound to oxygen
- C08K5/53—Phosphorus bound to oxygen bound to oxygen and to carbon only
- C08K5/5313—Phosphinic compounds, e.g. R2=P(:O)OR'
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/02—Flame or fire retardant/resistant
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/08—Stabilised against heat, light or radiation or oxydation
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/10—Transparent films; Clear coatings; Transparent materials
Abstract
The invention discloses a pyrazole-rich flame retardant and a preparation method thereof, wherein the preparation method of the pyrazole-rich flame retardant comprises the following steps: s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 30-180 ℃ for 4-24 h; s2: adding DOPO into a reaction vessel of S1, and reacting for 4-24h at 30-180 ℃; s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant. The pyrazole-rich flame retardant prepared by the invention has good flame retardance, is used for modifying epoxy resin, not only improves the flame retardance of the epoxy resin, but also improves the thermal stability, transparency and the like of the epoxy resin, so that the composite material has the characteristic of multiple functions.
Description
Technical Field
The invention relates to the technical field of organic flame retardants, in particular to a pyrazole-rich flame retardant and a preparation method thereof.
Background
Epoxy resin has the characteristics of excellent mechanical property, corrosion resistance, good compactness and stable chemical property, and is widely applied to various aspects of life such as coating, composite materials, casting materials, adhesives, mould pressing materials, injection molding materials and the like. However, because epoxy resin is flammable, once a fire occurs, most of the fire can spread, and great threat is caused to the economy and life of the people. Therefore, it is an important task to modify the flame retardancy of epoxy resins.
Phosphorus flame retardants are currently considered to be a class of flame retardants with high efficiency and environmental protection, but most of the existing phosphorus flame retardants contain fluorine, and harmful gases with great harm are generated during combustion.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides a pyrazole-rich flame retardant and a preparation method thereof, which are used for modifying epoxy resin and improving the flame retardant property of the epoxy resin.
The molecular structure of the pyrazole-rich flame retardant provided by the invention is as follows:
the synthetic route of the pyrazole-rich flame retardant provided by the invention is as follows:
the preparation method of the pyrazole-rich flame retardant provided by the invention comprises the following steps:
s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 30-180 ℃ for 4-24 h;
s2: adding DOPO into a reaction vessel of S1, and reacting for 4-24h at 30-180 ℃;
s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.
Preferably, the molar volume ratio of the 5-amino-3-methyl-1-phenylpyrazole, the p-benzaldehyde and the DOPO, the first solvent and the second solvent is 1mol:0.1-10mol:0.1-10mol:5-200 ml.
Preferably, the first solvent is one or more of N, N-dimethylformamide, ethanol, toluene and carbon tetrachloride; the second solvent is dichloromethane or water or a mixed solution thereof.
Preferably, the drying conditions in S3 are: vacuum drying at 50-65 deg.C for 20-26 h.
The invention provides application of a pyrazole-rich flame retardant in preparation of a flame-retardant high polymer material.
The action mechanism is as follows:
the phosphorus-containing flame retardant is pyrolyzed at a high temperature to generate P and PO radicals, and H and O radicals generated in the gas phase combustion process are captured by the radicals to reduce the concentration of the radicals, thereby inhibiting the combustion. In addition, the epoxy resin thermosetting material can be promoted to form a carbon layer, which can be used as a physical barrier to prevent flame from spreading to the interior of the material. The flame retardant containing nitrogen elements can release ammonia gas, water vapor, nitric oxide, nitrogen dioxide and other non-combustible gases after being heated and decomposed. The presence of these non-flammable gases greatly reduces the concentration of flammable gases produced by the decomposition of the epoxy resin, thereby reducing the temperature at the surface of the epoxy thermoset.
Compared with the prior art, the invention has the beneficial technical effects that:
(1) the resin matrix contains two flame-retardant elements of phosphorus and nitrogen, and the two flame-retardant elements can not only exert respective flame-retardant advantages in practical application, but also have a synergistic flame-retardant effect, so that the obtained flame-retardant epoxy resin has the characteristics of excellent thermal stability and flame-retardant property, only 5% of flame retardant is required to be added, and the limit oxygen index of the prepared epoxy resin can reach about 30%; in the existing flame retardant DOPO-PHM synthesized by using DOPO, aniline and 4-hydroxybenzaldehyde as raw materials, when the addition amount of the flame retardant exceeds 10%, the limiting oxygen index can reach 29.0%.
(2) The pyrazole-rich flame retardant designed by the invention has the advantages that two ends of the molecular structure contain DOPO, the compatibility in the epoxy resin is good, and the flame retardant can be fully combined with the epoxy resin to obtain the transparent flame-retardant epoxy resin with good comprehensive performance.
Drawings
FIG. 1 is a nuclear magnetic resonance image of a pyrazole-rich flame retardant according to the present invention;
FIG. 2 is an infrared spectrum of a pyrazole-rich flame retardant according to the present invention;
FIG. 3 is an electron micrograph of an epoxy resin comprising a pyrazole-rich flame retardant of the present invention after combustion.
Detailed Description
The present invention will be further illustrated with reference to the following specific examples.
Example 1
The preparation method of the pyrazole-rich flame retardant provided by the invention comprises the following steps:
s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring for 4 hours at 30 ℃;
s2: adding DOPO into a reaction vessel of S1, and reacting for 4h at 30 ℃;
s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.
The molar ratio of the 5-amino-3-methyl-1-phenylpyrazole to the p-benzaldehyde to the DOPO to the first solvent was 1mol:0.1mol:0.1mol:5 ml.
The first solvent is N, N-dimethylformamide; the second solvent is dichloromethane.
The drying conditions in S3 were: drying at 50 deg.C under vacuum for 20 h.
Example 2
The preparation method of the pyrazole-rich flame retardant provided by the invention comprises the following steps:
s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 180 ℃ for 24 hours;
s2: adding DOPO into a reaction vessel of S1, and reacting for 24h at 180 ℃;
s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.
The molar ratio of the 5-amino-3-methyl-1-phenylpyrazole to the p-benzaldehyde to the DOPO to the first solvent is 1mol:10mol:10mol:200 ml.
The first solvent is a mixed solution of N, N-dimethylformamide and ethanol; the second solvent is a mixed solution of dichloromethane and water.
The drying conditions in S3 were: dried under vacuum at 65 ℃ for 26 h.
Example 3
The preparation method of the pyrazole-rich flame retardant provided by the invention comprises the following steps:
s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring for 14h at 105 ℃;
s2: adding DOPO into a reaction vessel of S1, and reacting for 14h at 105 ℃;
s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.
The molar ratio of the 5-amino-3-methyl-1-phenylpyrazole to the p-benzaldehyde to the DOPO to the first solvent is 1mol:5mol:5mol:100 ml.
The first solvent is toluene; the second solvent is water.
The drying conditions in S3 were: dried under vacuum at 58 ℃ for 23 h.
Application example
Preparation of flame-retardant epoxy resin
Weighing 25.00g of epoxy resin, heating to 95 ℃, adding 5 wt% of the pyrazole-rich flame retardant prepared in example 3, stirring to be transparent under vacuum pumping, adding 6.5g of curing agent 4,4' -diaminodiphenylmethane (DDM), continuing to pump until the mixture is completely dissolved, pouring the mixture into a mold, and sequentially curing at 100 ℃ for 3h, 125 ℃ for 3h and 160 ℃ for 2h to obtain the flame-retardant epoxy resin.
Test for flame retardancy
The materials were tested for flame retardancy according to test standards ASTM D380 and ASTM D2863-97, and three parallel tests were carried out on the flame retardant epoxy resin prepared in example 3, the specific test results are shown in Table 1.
TABLE 1 LOI and UL94 vertical burn test for EP and EP/PPMD materials
| sample | UL94(3.2m) | LOI(％) |
| EP | N.R | 25.8 |
| EP/5％PPMD(1) | V-0 | 30.7 |
| EP/5％PPMD(2) | V-0 | 30.9 |
| EP/5％PPMD(3) | V-0 | 30.8 |
As can be seen from Table 1, the flame retardant prepared by the method can enable the limiting oxygen index to reach more than 30% only by adding 5% of the flame retardant into epoxy resin, while the limiting oxygen index can reach 29.0% only by using the conventional flame retardant DOPO-PHM synthesized by using DOPO, aniline and 4-hydroxybenzaldehyde as raw materials when the addition amount of the flame retardant exceeds 10%.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (6)
1. The pyrazole-rich flame retardant is characterized in that the molecular structure is as follows:
2. the synthetic route of the pyrazole-rich flame retardant of claim 1 is as follows:
3. the method of preparing a pyrazole-rich flame retardant of claim 1, comprising the steps of:
s1: sequentially adding 5-amino-3-methyl-1-phenylpyrazole, p-benzaldehyde and a first solvent into a reaction vessel, and stirring at 30-180 ℃ for 4-24 h;
s2: adding DOPO into a reaction vessel of S1, and reacting for 4-24h at 30-180 ℃;
s3: and filtering the solution after the reaction in the S2, dissolving the crude product obtained by filtering in a second solvent to remove impurities in the crude product, and drying the solid product after filtering to obtain the pyrazole-rich flame retardant.
4. The method of preparing a pyrazole-rich flame retardant according to claim 3, wherein the molar volume ratio of the 5-amino-3-methyl-1-phenylpyrazole, the p-benzaldehyde, the DOPO and the first solvent is 1mol:0.1-10mol:0.1-10mol:5-200 ml.
5. The method for preparing a pyrazole-rich flame retardant according to claim 3, wherein the first solvent is one or more of N, N-dimethylformamide, ethanol, toluene and carbon tetrachloride; the second solvent is dichloromethane or water or a mixed solution thereof.
6. The method of preparing a pyrazole-rich flame retardant of claim 3, wherein the drying conditions in S3 are: vacuum drying at 50-65 deg.C for 20-26 h.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010151059.6A CN111269265A (en) | 2020-03-06 | 2020-03-06 | Pyrazole-rich flame retardant and preparation method thereof |
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| CN202010151059.6A CN111269265A (en) | 2020-03-06 | 2020-03-06 | Pyrazole-rich flame retardant and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113698737A (en) * | 2021-10-15 | 2021-11-26 | 湖南美莱珀科技发展有限公司 | Flame-retardant material, master batch containing flame-retardant material and preparation method of master batch |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113698737A (en) * | 2021-10-15 | 2021-11-26 | 湖南美莱珀科技发展有限公司 | Flame-retardant material, master batch containing flame-retardant material and preparation method of master batch |
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Application publication date: 20200612 |