CN111793237B - Production method of rigid polyimide foam material - Google Patents
Production method of rigid polyimide foam material Download PDFInfo
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- CN111793237B CN111793237B CN202010706620.2A CN202010706620A CN111793237B CN 111793237 B CN111793237 B CN 111793237B CN 202010706620 A CN202010706620 A CN 202010706620A CN 111793237 B CN111793237 B CN 111793237B
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- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
- C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
- C08J9/125—Water, e.g. hydrated salts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/32—Component parts, details or accessories; Auxiliary operations
- B29C43/52—Heating or cooling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
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- C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
- C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
- C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08G73/1003—Preparatory processes
- C08G73/1007—Preparatory processes from tetracarboxylic acids or derivatives and diamines
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- C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
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- C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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- C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
- C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08G73/1067—Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound
- C08G73/1071—Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
- B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
- B29C2035/0855—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using microwave
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- C08J2203/00—Foams characterized by the expanding agent
- C08J2203/10—Water or water-releasing compounds
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- C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
- C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2479/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2461/00 - C08J2477/00
- C08J2479/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08J2479/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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Abstract
The invention belongs to the technical field of plastic foaming, and particularly relates to a production method of a rigid polyimide foam material, which comprises the steps of mixing imide acid precursor powder and imide ester precursor powder, adding a foam stabilizer and/or a foaming agent, uniformly mixing, and preparing the rigid polyimide foam material through foam molding; wherein, the imide acid precursor powder is prepared by the reaction of binary anhydride and diamine; the imide ester precursor powder is prepared by reacting dianhydride and fatty alcohol to prepare diacid diester and then reacting the diacid diester with isocyanate; the material has good mechanical property, flame retardant property, high and low temperature resistance and other properties, and can be used as a structural member in the fields of aerospace, marine ships and warships and the like.
Description
Technical Field
The invention belongs to the technical field of plastic foaming, and particularly relates to a production method of a rigid polyimide foam material.
Background
Polyimide is a polymer having an imide ring (-CO-N-CO-) in its main chain. It has the characteristics of excellent heat resistance, low temperature resistance, dilute acid resistance, mechanical property, dielectric property, low thermal expansion coefficient, high radiation resistance, self-extinguishing flame retardant property and no toxicity. The polyimide foam has strong heat resistance, good flame retardance, no harmful gas generation and easy installation, is a heat-insulating and noise-reducing material with wide application, and is widely applied to the fields of aviation, aerospace, navigation, transportation, buildings and the like. Used for body filling, pipe wrapping, radar protection covers and the like, and has the functions of heat preservation, heat insulation, noise reduction and the like.
At present, polyimide foam is researched to be used as a heat and sound insulation material for surface ships and submarines, for example, SOLIMIDE foam is used for a heat and sound insulation system of naval ships in multiple countries, and the polyimide foam is also widely applied to civil ships such as luxury cruise ships, speed boats and liquefied natural gas ships.
The soft open-cell polyimide foam has poor mechanical properties, cannot be used as structural foam, has low closed-cell rate, cannot effectively isolate water vapor, and is difficult to protect internal devices. The rigid polyimide structural foam has the characteristics of high temperature resistance, high strength, high closed porosity and the like, and can be used as structural foam, such as wings, missile cabins, speed reduction bearing plates, relay frameworks, shells and the like. The hard closed-cell polyimide foam material can be used for coatings of airplane luggage racks, ceilings and the like, expands after being heated, and cannot catch fire; it can also be used as fire-proof explosion-suppressing filler for fuel tank of aircraft. In addition, the rigid polyimide foam material can also be used as a honeycomb structure material, namely, a certain amount of polyimide precursor powder is put into a porous material and foamed in situ to obtain the rigid foam filled honeycomb material, the tensile strength, the compression strength and the shear strength of the foam material are greatly improved, and meanwhile, the high-temperature resistance of the polyimide improves the service temperature of the honeycomb material.
At present, rigid polyimide foam materials are generally prepared by two methods: one-step and two-step processes. The one-step method is characterized in that dianhydride and isocyanate are used as main raw materials, a one-step polycondensation method is adopted to prepare the high-temperature-resistant rigid polyimide foam, for example, in patent application CN201010591827.6, the high-temperature-resistant rigid polyimide foam is foamed for 3-30 min under the pressure of 1-20 MPa by adopting the one-step method, then is shaped for 1-30 min under the microwave pressure of 1-20 MPa, and finally is placed in a nitrogen-filled oven to be cured to obtain the rigid polyimide foam structural material, wherein the Shore hardness is 57 HC-64 HC, the compression strength is 0.9-1.8 MPa, and the tensile strength is 1.9-2.9 MPa. And then, as in patent application CN201610827030.9, the foaming material is put into a vacuum ultraviolet curing box with the temperature of 60-80 ℃ for reaction for 1-2 h to obtain a foaming precursor by adopting a one-step method, and then the foaming precursor is put into a vacuum freeze dryer for 4-6 h to obtain high-strength polyimide foam. The vacuum ultraviolet curing box has the function of improving the stability and the hardness of the material, and the vacuum freeze dryer has the function of improving the tensile strength and the compressive strength of the material, and the polyimide foam material prepared by the method has the glass transition temperature of 268-298 ℃, the tensile strength of 3.1-3.9 MPa and the compressive strength of 2.1-2.6 MPa. Also, for example, patent application CN201710035692.7 uses a one-step process to obtain a dispersion by ultrasonic dispersionFoaming the foam precursor and the modified black material at normal pressure, and self-curing to obtain the reinforced and toughened self-curing rigid polyimide foam material. The density range is 76-113Kg/m3(ii) a The tensile strength is 2.56-3.23 MPa; the breaking strength is 379-873N/m; the long-term working temperature resistance is 380-450 ℃, the glass microspheres, the glass fibers and the like are added in the patent application, the strength and the toughness of the product can be improved, the complexity of the production process is increased, and the control is difficult. Thus, the following results are obtained: the one-step method has the advantages of simple preparation process, short period, easy operation of instruments and equipment, uniform pore size of the prepared foam and stable performance, but has the defects of great influence of raw material proportion on the cell structure, difficult control of release of a large amount of heat in the foaming process, and incapability of obtaining high-density materials by adopting the one-step method to prepare the rigid polyimide foam material, so that the mechanical property of the rigid polyimide foam material cannot reach the best.
The two-step method is to generate a polyimide intermediate by reacting anhydride with amine and then to foam the intermediate to form polyimide foam. For example, patent application CN201710660725.7 adopts a two-step method to mix and dry dianhydride, diamine, other auxiliary agents and solvents, then the mixture is crushed to obtain precursor powder, then the precursor powder is placed in a high-pressure container, and the high-pressure container is vacuumized and charged with CO2Heating and pressurizing to react to obtain the hard closed-cell polyimide foam material, and CO2The main functions are that the resin enters a supercritical state at high temperature and high pressure and then is dissolved and diffused in polyimide, the resin is kept at the high temperature for a period of time, and then the resin releases gas after the viscosity of the resin is increased to foam and solidify, and meanwhile, the function of adjusting the environmental pressure is achieved, and the expansion rate of the gas in a foam system is controlled. The density of the obtained polyimide foam material is 40-105 kg/m3The closed porosity is 83-95%, the compression strength is 0.44-1.49 MPa, the method has high closed porosity and wide density adjusting range, but the supercritical technology is adopted to lead gas to be input into the reaction system from the outside to be foamed and molded, and the process requirement is higher. Thus, it can be seen that: the two-step method has the advantages that the prepared foam plastic has better comprehensive performance, but the foaming process is more complex and the production cost is higher.
Therefore, the hard polyimide foam material with good mechanical property, high and low temperature resistance and excellent flame retardant property is developed, and can be used as a structural material for the fields of aerospace, marine ships and warships and the like.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a production method of a rigid polyimide foam material.
The method is realized by the following technical scheme:
a production method of a rigid polyimide foam material comprises the steps of mixing imide acid precursor powder and imide ester precursor powder, adding a foam stabilizer and/or a foaming agent, uniformly mixing, and carrying out foaming mould pressing to obtain the rigid polyimide foam material; wherein, the imide acid precursor powder is prepared by the reaction of binary anhydride and diamine; the imide ester precursor powder is prepared by reacting dianhydride and fatty alcohol to prepare diacid diester and then reacting the diacid diester with isocyanate.
Further, the production method of the rigid polyimide foam material comprises the following steps:
(1) preparation of polyamic acid precursor powder: adding dibasic anhydride and diamine into a polar solvent, stirring to obtain a polyamic acid precursor solvent, and heating and drying to obtain polyamic acid precursor powder;
(2) preparation of polyamide resin precursor powder: adding dibasic anhydride and fatty alcohol into a polar solvent, stirring, adding isocyanate, stirring to obtain a polyamide ester precursor solution, and heating and drying to obtain polyamide ester precursor powder;
(3) preparing a foaming precursor: stirring the polyamic acid precursor powder obtained in the step (1) and the polyamide ester precursor powder obtained in the step (2), adding a foam stabilizer and a foaming agent, and stirring to obtain a foaming precursor;
(4) and (3) mould pressing foaming molding: adding the foaming precursor into a mold, and placing the mold in a microwave oven for mold pressing and foaming molding;
(5) high-temperature curing: and (4) taking out the formed foam in the step (4), and placing the formed foam in an oven for heating and curing to obtain the rigid polyimide foam material.
Further, in the step (1) or (2), the dibasic anhydride is any one or more of 3,3',4,4' -diphenyl ether tetracarboxylic dianhydride (ODPA), 2,3,3',4' -diphenyl ether tetracarboxylic dianhydride (α -ODPA), 3,3',4,4' -biphenyl sulfone tetracarboxylic dianhydride (DSDA), bisphenol a type diphenyl ether dianhydride (BPADA), 3,3',4,4' -Benzophenone Tetracarboxylic Dianhydride (BTDA), 2,3,3',4' -benzophenone tetracarboxylic dianhydride (α -BTDA), 3,3',4,4' -biphenyl tetracarboxylic dianhydride (s-BPDA), 2,3',4,4' -biphenyl tetracarboxylic dianhydride (α -BPDA), 1,2,4, 5-pyromellitic dianhydride (PMDA).
Further, in the step (1), the diamine is any one or more of p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), 3 '-diaminobenzophenone (3,3' -DABP), 3,4 '-diaminobenzophenone (3,4' -DABP), 4 '-diaminobenzophenone (4,4' -DABP), 3,4 '-diaminodiphenyl ether (3,4' -ODA), 4 '-diaminodiphenyl ether (4,4' -ODA), bisphenol a diphenyl ether diamine (BAPP).
Further, in the step (1) or (2), the polar solvent is any one or more of tetrahydrofuran, 2-chloropyridine, 2, 6-dichloropyridine, dimethyl sulfoxide, N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide, propylene glycol methyl ether and dipropylene glycol dimethyl ether.
Further, in the step (1), the polyamic acid precursor solution is prepared from the following raw materials in parts by weight: 1-5 parts of dibasic anhydride, 0.5-4 parts of diamine and 4-20 parts of polar solvent.
Further, in step (1) or (2), the heating and drying are carried out, and the process parameters are as follows: the vacuum degree is-0.3 to-0.1 MPa, the temperature is 80 to 180 ℃, and the time is 3 to 10 hours.
The invention ensures that the precursor powder has better uniformity by controlling the vacuum degree; the drying temperature of the method is required to be 80-180 ℃ to ensure that the precursor powder can be fully dried, and if the heating and drying time is short, the solvent in the reaction system is not fully volatilized.
Further, in the step (2), the aliphatic alcohol is any one or more of methanol, ethanol, ethylene glycol, propanol, isopropanol, n-butanol, n-octanol and dodecanol.
Further, in the step (2), the isocyanate is any one or more of phenyl diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, polyphenyl polymethylene polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, tetramethylxylylene diisocyanate, 4' -diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, and dimethylbiphenyl diisocyanate.
Further, in the step (2), the polyamide resin precursor solution is prepared from the following raw materials in parts by weight: 10-20 parts of dibasic anhydride, 5-15 parts of fatty alcohol, 20-30 parts of polar solvent and 10-30 parts of isocyanate.
According to the invention, by controlling the mass ratio of the reaction raw materials of the polyesteramide precursor, the reaction groups are fully reacted, and the molecular chain of the precursor can be ensured to effectively form an expected length, so that the properties such as product strength and the like are improved.
Further, in the step (3), the foam stabilizer is any one or more of polysiloxane, tetramethyl silicone oil, AK series silicone oil, DC series silicone oil, silicone polyether copolymer, organosilicon and silicone.
Further, in step (3), the foaming agent is water.
Further, in the step (3), the foaming precursor comprises the following raw materials in parts by weight: 100-300 parts of polyamic acid precursor powder, 50-300 parts of polyamide resin precursor powder, 1-20 parts of foam stabilizer and 0-10 parts of foaming agent. By controlling the raw material mass ratio of the foaming precursor, the bad results of mismatching of foaming gel and foaming and the like are effectively avoided, so that the later-stage foaming forming effect is influenced.
Further, in the steps (1), (2) and (3), the rotation speed of the stirring is 300-800 r/min, and the time is 5-30 min.
Further, in the step (4), the compression molding process is as follows: the microwave power is 2000W-6000W, the temperature is 120 ℃ to 300 ℃, and the pressure is 2MPa to 10 MPa. The invention achieves good curing effect by controlling the microwave power, if the microwave power is less than 2000W, the curing is incomplete, and if the microwave power is more than 6000W, the product molecules vibrate too fast, the formed molecular bonds are easy to break, and the product cracks and the like.
Further, in step (5), the heating manner is: the heating temperature is 120-350 ℃, and the heating time is 0.5-5 h. The post-curing temperature is too low, so that the curing is insufficient, the mechanical property and the like of the product are influenced, and the post-curing temperature is too high, so that the molecular bond is damaged by the excessive heating of the product, and the stability of the product is influenced. The method not only effectively cures, but also reduces post-curing conditions.
Has the advantages that:
(1) the rigid polyimide foam material disclosed by the invention has excellent performances such as good mechanical property, flame retardant property, high and low temperature resistance and the like, and can be used as a structural member in the fields of aerospace, marine ships and warships and the like.
(2) The high-density polyimide material is prepared by adopting a two-step method, and the microwave mould pressing is adopted, so that the material is favorably formed and solidified, and the mechanical property of the material is improved.
(3) The method has the characteristics of high production efficiency, accurate product size, smooth surface, easy curing and shaping, high product utilization rate and suitability for mass production.
Detailed Description
The following description will explain the embodiments of the present invention in further detail, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are still within the scope of the present invention as claimed in the claims.
Example 1
A method for producing a rigid polyimide foam material comprises the following steps:
(1) preparation of polyamic acid precursor powder: adding dibasic anhydride and diamine into a polar solvent, stirring to obtain a polyamic acid precursor solvent, and heating and drying to obtain polyamic acid precursor powder;
(2) preparation of polyamide resin precursor powder: adding dibasic anhydride and fatty alcohol into a polar solvent, stirring, adding isocyanate, stirring to obtain a polyamide ester precursor solution, and heating and drying to obtain polyamide ester precursor powder;
(3) preparing a foaming precursor: stirring the polyamic acid precursor powder obtained in the step (1) and the polyamide ester precursor powder obtained in the step (2), adding a foam stabilizer and a foaming agent, and stirring to obtain a foaming precursor;
(4) and (3) mould pressing foaming molding: adding the foaming precursor into a mold, and placing the mold in a microwave oven for mold pressing and foaming molding;
(5) high-temperature curing: taking out the formed foam in the step (4), and placing the formed foam in an oven to be heated and cured to prepare a hard polyimide foam material;
in the steps (1) and (2), the binary anhydride is 3,3',4,4' -diphenyl ether tetracarboxylic dianhydride;
in the step (1), the diamine is p-phenylenediamine;
in steps (1) and (2), the polar solvent is tetrahydrofuran;
in the step (1), the polyamic acid precursor solution is prepared from the following raw materials in parts by weight: 3 parts of binary anhydride, 1 part of diamine and 10 parts of polar solvent;
in the steps (1) and (2), the heating drying is carried out, and the process parameters are as follows: the vacuum degree is-0.2 MPa, the temperature is 120 ℃, and the time is 5 h;
in step (2), the aliphatic alcohol is methanol;
in the step (2), the isocyanate is phenyl diisocyanate;
in the step (2), the polyamide resin precursor solution is prepared from the following raw materials in parts by weight: 10 parts of dibasic anhydride, 5 parts of fatty alcohol, 20 parts of polar solvent and 10 parts of isocyanate;
in the step (3), the foam stabilizer is polysiloxane;
in step (3), the foaming agent is water;
in the step (3), the foaming precursor comprises the following raw materials in parts by weight: 200 parts of polyamide acid precursor powder, 180 parts of polyamide ester precursor powder, 13 parts of foam stabilizer and 5 parts of foaming agent;
in the steps (1), (2) and (3), the stirring speed is 500r/min, and the time is 15 min;
in the step (4), the compression molding process comprises the following steps: the microwave power is 2000W-6000W, the temperature is 210 ℃, and the pressure is 4 MPa;
in step (5), the heating mode is as follows: the heating temperature is 120 ℃, and the heating time is 0.5 h.
Example 2
The difference from the embodiment 1 is that: in the step (1), the parts of the binary anhydride, the diamine and the polar solvent are 3, 2 and 5, and other conditions are not changed.
Example 3
The difference from the embodiment 1 is that: in the steps (1) and (2), the heating and drying process comprises the following steps: putting the solvent into a vacuum drying oven, and vacuumizing to-0.2 MPa at 150 ℃ for 5 hours. The other conditions were not changed.
Example 4
The difference from the example 1 is that: in the step (2), the parts of the dibasic anhydride, the fatty alcohol, the polar solvent and the isocyanate are 15, 10, 25 and 20, and other conditions are not changed.
Example 5
The difference from the embodiment 1 is that: in the step (3), the parts of the polyamic acid precursor powder, the polyamide ester precursor powder, the foam stabilizer and the foaming agent are 150, 100, 5 and 0, and other conditions are not changed.
Example 6
The difference from the example 1 is that: in the step (3), the parts of the polyamic acid precursor powder, the polyamide ester precursor powder, the foam stabilizer and the foaming agent are 150, 100, 5 and 3, and other conditions are not changed.
Example 7
The difference from the embodiment 1 is that: in the step (4), the compression molding process comprises the following steps: adopting microwave mould pressing, wherein the microwave power is as follows: 5000W, the temperature is 150 ℃, the pressure is 6MPa, and other conditions are unchanged.
Example 8
The difference from the example 1 is that: in the step (5), the heating temperature of the oven is 200 ℃, and the heating time is 2 h.
The experimental results of the above examples 1 to 8 are shown in the following table 1;
TABLE 1
As can be seen from the experimental data in Table 1, the rigid polyimide foam material prepared by the method has the properties of adjustable density, good mechanical property, excellent flame retardant property and the like.
In addition, the inventor respectively adopts alpha-ODPA, DSDA, BPADA, BTDA, alpha-BTDA, s-BPDA, alpha-BPDA and PMDA as reaction raw materials, and finds that the performance test result is not significantly different from that of example 3; in the invention, the combination of any several of ODPA, alpha-ODPA, DSDA, BPADA, BTDA, alpha-BTDA, s-BPDA, alpha-BPDA and PMDA is used as a reaction raw material, and the product performance is found to have no obvious difference with the result of a single raw material.
The inventor respectively adopts m-PDA, 3' -DABP, 3,4' -DABP, 4' -DABP, 3,4' -ODA, 4' -ODA and BAPP as reaction raw materials, and finds that the performance test result is not obviously different from that of example 6; in the invention, any combination of p-PDA, m-PDA, 3' -DABP, 3,4' -DABP, 4' -DABP, 3,4' -ODA, 4' -ODA and BAPP is used as a reaction raw material, and the product performance is found to have no significant difference from the result of a single raw material.
In view of the influence on the dissolution behavior of the reaction raw materials, the present inventors found that: tetrahydrofuran, 2-chloropyridine, 2, 6-dichloropyridine, dimethyl sulfoxide, N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide, propylene glycol methyl ether and dipropylene glycol dimethyl ether are used as solvents, and a good dissolving phenomenon is shown.
In consideration of the action relationship of the substituent groups and the substituent sites of the polyamide resin, the invention discovers that: any one or more of phenyl diisocyanate, p-phenylene diisocyanate, diphenyl methane diisocyanate, polyphenyl polymethylene polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, tetramethyl phenyl dimethylene diisocyanate, 4' -diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate and dimethyl biphenyl diisocyanate can be selected to realize the production of the foam material with high density and good mechanical property.
In consideration of the functional relationship between the molecular size of the polyamide resin and the mechanical property and density, the invention discovers that: methanol, ethanol, ethylene glycol, propanol, isopropanol, n-butanol, n-octanol and dodecanol are selected as reaction raw materials, and stable and good mechanical properties can be realized.
In view of the closed cell fraction, density requirements, and the compatibility and foaming properties of the reaction raw materials, the present inventors have found that: polysiloxane, tetramethyl silicone oil, AK series silicone oil (such as AK8803 and AK8805), DC series silicone oil (such as DC19 and DC198), silicone polyether copolymer, organosilicon and silicone are selected as foam homogenizing agents, so that a foaming system with good stability, uniform distribution and uniform cell size can be formed.
In conclusion, the method adopts the reaction of dicarboxylic anhydride and diamine to obtain imide acid, the reaction of dianhydride and fatty alcohol to obtain diacid diester, the reaction of diacid diester and isocyanate to obtain imide ester, the mixture of the two imides is added with a foam stabilizer and a foaming agent for mixing, and the rigid polyimide foam material is obtained through microwave mould pressing foaming, wherein the density range of the rigid polyimide foam material prepared by the method is 70-300 Kg/m3The tensile strength is 0.8-4 MPa, the compressive strength is 1.5-5 MPa, and the limiting oxygen index is 35% -45%, which shows that the polyimide foam has the characteristics of good mechanical property, flame retardant property and the like, and is applied to the fields of aerospace, marine ships and warships and the like as a structural member, which also shows that the polyimide foam produced by the method has good stability, is easy for large-scale production, and can be popularized and applied in a large scale.
Claims (8)
1. A production method of a rigid polyimide foam material is characterized by comprising the following steps:
(1) preparation of polyamic acid precursor powder: weighing 1-5 parts of dibasic anhydride, 0.5-4 parts of diamine and 4-20 parts of polar solvent, adding the dibasic anhydride and the diamine into the polar solvent, stirring to obtain a polyamic acid precursor solvent, and heating and drying to obtain polyamic acid precursor powder;
(2) preparation of polyamide ester precursor powder: weighing 10-20 parts of dibasic anhydride, 5-15 parts of fatty alcohol, 20-30 parts of polar solvent and 10-30 parts of isocyanate, adding the dibasic anhydride and the fatty alcohol into the polar solvent, stirring, adding the isocyanate, stirring to obtain polyamide ester precursor solution, and heating and drying to obtain polyamide ester precursor powder;
(3) preparing a foaming precursor: weighing 300 parts of polyamic acid precursor powder, 50-300 parts of polyamide resin precursor powder, 1-20 parts of foam stabilizer and 0-10 parts of foaming agent, stirring the polyamic acid precursor powder in the step (1) and the polyamide resin precursor powder in the step (2), adding the foam stabilizer and the foaming agent, and stirring to obtain a foaming precursor;
(4) and (3) mould pressing foaming molding: adding the foaming precursor into a mold, placing the mold in a microwave oven, and carrying out mold pressing foaming molding under the conditions that the microwave power is 2000W-6000W, the temperature is 120-300 ℃, and the pressure is 2-10 MPa;
(5) high-temperature curing: taking out the formed foam obtained in the step (4), placing the formed foam in an oven, and heating and curing the formed foam for 0.5 to 5 hours at the temperature of 120 to 350 ℃ to obtain a hard polyimide foam material;
the polar solution is one or more of tetrahydrofuran, 2-chloropyridine, 2, 6-dichloropyridine, dimethyl sulfoxide, N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide, propylene glycol methyl ether and dipropylene glycol dimethyl ether.
2. The method for producing a rigid polyimide foam according to claim 1, wherein the dibasic anhydride is any one or more of 3,3',4,4' -diphenyl ether tetracarboxylic dianhydride, 2,3,3',4' -diphenyl ether tetracarboxylic dianhydride, 3,3',4,4' -biphenyl sulfone tetracarboxylic dianhydride, bisphenol a type diphenyl ether dianhydride, 3,3',4,4' -benzophenone tetracarboxylic dianhydride, 2,3,3',4' -benzophenone tetracarboxylic dianhydride, 3,3',4,4' -biphenyl tetracarboxylic dianhydride, 2,3',4,4' -biphenyl tetracarboxylic dianhydride, 1,2,4, 5-pyromellitic dianhydride.
3. The method for producing a rigid polyimide foam according to claim 1, wherein the diamine is any one or more of p-phenylenediamine, m-phenylenediamine, 3' -diaminobenzophenone, 3,4' -diaminobenzophenone, 4' -diaminobenzophenone, 3,4' -diaminodiphenyl ether, 4' -diaminodiphenyl ether, bisphenol a diphenyl ether diamine.
4. The method for producing a rigid polyimide foam according to claim 1, wherein the aliphatic alcohol is any one or more of methanol, ethanol, ethylene glycol, propanol, isopropanol, n-butanol, n-octanol and dodecanol.
5. The method for producing a rigid polyimide foam according to claim 1, wherein said isocyanate is any one or more of p-phenylene diisocyanate, polyphenyl polymethylene polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, tetramethylxylylene diisocyanate, 1, 5-naphthalene diisocyanate, and dimethylbiphenyl diisocyanate.
6. The method for producing the rigid polyimide foam according to claim 1, wherein the foam stabilizer is one or more of a silicone polyether copolymer and silicone.
7. The method for producing the rigid polyimide foam according to claim 1, wherein the blowing agent is water.
8. The method for producing the rigid polyimide foam according to claim 1, wherein the heating and drying are carried out under the following process parameters: the vacuum degree is-0.3 to-0.1 kPa, the temperature is 80 to 180 ℃, and the time is 3 to 10 hours.
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| CN114213696A (en) * | 2021-12-31 | 2022-03-22 | 四川大学 | Light flexible high-temperature-resistant heat-insulating polyimide foam and preparation method and application thereof |
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| US3554935A (en) * | 1968-03-12 | 1971-01-12 | Monsanto Co | Polyimide foams |
| MX150388A (en) * | 1969-01-31 | 1984-04-30 | Union Carbide Corp | IMPROVED PROCEDURE TO PROVIDE A SECOND BACKUP ON CARPETING MATERIAL |
| DE1962900C3 (en) * | 1969-12-16 | 1982-04-29 | Bayer Ag, 5090 Leverkusen | Polyamide imide esters and process for their preparation |
| US4687785A (en) * | 1985-08-27 | 1987-08-18 | Thermal Science, Inc. | Thermally adaptive polymers and prepolymers and methods of making in which an imide is formed from a polyanhydride oligomer and an isocyanate |
| US4923651A (en) * | 1989-06-30 | 1990-05-08 | Sorrento Engineering, Inc. | Method of manufacturing polyimide foam shapes having improved density and cell size uniformity |
| US5288842A (en) * | 1991-01-30 | 1994-02-22 | International Business Machines Corporation | Morphological composite materials formed from different precursors |
| KR0161313B1 (en) * | 1994-10-31 | 1999-01-15 | 강박광 | Polyimide amicester and process for preparing the same |
| CN102127225A (en) * | 2010-12-08 | 2011-07-20 | 北京市射线应用研究中心 | Hard polyimide foaming structural material and preparation method thereof |
| CN102604089B (en) * | 2011-05-23 | 2013-09-25 | 溧阳华晶电子材料有限公司 | Preparation method of low-density polyimide soft foam |
| CN103275319B (en) * | 2013-06-14 | 2015-09-16 | 中国科学院长春应用化学研究所 | Polyimide foam and preparation method thereof |
| CN103709749B (en) * | 2013-12-25 | 2015-12-02 | 北京排头兵科技有限公司 | A kind of Polyimide foams and preparation method thereof |
| CN105153422B (en) * | 2015-10-08 | 2017-07-18 | 清华大学 | A kind of Polyimide foams and preparation method thereof |
| CN105924649B (en) * | 2016-05-19 | 2019-06-18 | 航天材料及工艺研究所 | A kind of Polyimide foams and preparation method thereof |
| CN106317873A (en) * | 2016-09-14 | 2017-01-11 | 郑州峰泰纳米材料有限公司 | Method for preparing high-strength polyimide foam |
| CN106751826B (en) * | 2017-01-17 | 2019-02-01 | 自贡中天胜新材料科技有限公司 | A kind of activeness and quietness self-curing hard polyimide foaming and preparation method thereof |
| CN107540841B (en) * | 2017-08-04 | 2020-07-14 | 航天材料及工艺研究所 | Preparation method of hard closed-cell polyimide foam |
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