Silicon-containing anhydride compounds, methods for preparing the same, and polyimide compounds, methods for preparing the same, and applications

Abstract

The present disclosure relates to a silicon-containing anhydride compound, a method for preparing the same, and a polyimide compound, a method for preparing the same, and an application thereof. The silicon-containing anhydride compound has a structure represented by the following formula (1); and the polyimide compound has a structure represented by the following formula (2). x is 2, 3, or 4; and U represents a polymer chain including an imide repeating unit. The polyimide compound can be used as a filler for a polyamic acid solution, maintains heat resistance and dielectric properties of a polyimide, and avoids an influence on viscosity of the polyimide.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of polyimide, in particular, to a silicon-containing anhydride compound, a preparation method thereof, and a polyimide compound, a preparation method thereof and application. BACKGROUND

[0002] Polyimide (PI) refers to a kind of polymer containing imide ring (-CO-N-CO-) in the main chain, and is one of organic polymer materials with excellent comprehensive performance.

[0003] Polyimide can be obtained by low-temperature condensation of dianhydride and diamine in a polar solvent to obtain soluble polyamide acid, film formation or spinning, and then heated to about 300℃ to dehydrate and cyclize to polyimide; or adding acetic anhydride and tertiary amine catalyst to the polyamide acid to perform chemical dehydration and cyclization to obtain polyimide solution and powder. Diamine and dianhydride can also be heated and condensed in a high-boiling-point solvent, such as a phenolic solvent, to obtain polyimide in one step. In addition, polyimide can also be obtained by reacting diester of tetraacid and diamine; or polyisocyanide is first converted from polyamide acid, and then converted into polyimide.

[0004] In order to enhance the mechanical properties of polyimide, some studies have mixed organic fillers or inorganic fillers with the precursor (polyamide acid) of polyimide for modification. However, there are the following defects, for example: using general organic fillers to modify polyimide high polymer materials will weaken their heat resistance or dielectric properties; and general inorganic fillers (such as SiO2) contain too many heteroatoms, which enhances the intermolecular force due to hydrogen bonding, and the viscosity changes greatly. SUMMARY

[0005] The purpose of the present disclosure is to provide a silicon-containing anhydride compound, a preparation method thereof, and a polyimide compound, a preparation method thereof and application, which can be used as a filler for polyamide acid solution, maintain the heat resistance and dielectric properties of polyimide, and avoid affecting the viscosity of polyimide.

[0006] In order to achieve the above purpose, the first aspect of the present disclosure provides a silicon-containing anhydride compound, the structure of which is shown in the following formula (1):

[0007]

[0008] wherein x is selected from 2, 3 or 4; R is selected from one or more of substituted or unsubstituted alkyl with carbon atom number of 1-12 or substituted or unsubstituted aryl with carbon atom number of 6-30; each R2 is the same or different, and each is independently selected from substituted or unsubstituted arylene with carbon atom number of 6-30, or substituted or unsubstituted heteroarylene with carbon atom number of 2-30.

[0009] Optionally, the silicon-containing anhydride compound has the structure shown in formula (1-1):

[0010]

[0011] R2 is selected from phenylene or biphenylene.

[0012] A second aspect of this disclosure provides a method for preparing the silicon-containing acid anhydride compound described in the first aspect of this disclosure, comprising the following steps:

[0013] The first reactant is reacted with an organic acid and an anhydride; wherein the structure of the first reactant is shown in formula (1-2):

[0014]

[0015] Optionally, the organic acid is selected from one or more of acetic acid and trifluoroacetic acid; the acid anhydride is acetic anhydride; and the molar ratio of the first reactant to the organic acid and acid anhydride is 1:0.5-3:0.5-3.

[0016] Optionally, the reaction conditions include: under reflux heating, the reaction temperature is 60–120°C, and the reaction time is 4–24 h.

[0017] A third aspect of this disclosure provides a polyimide compound having the structure shown in formula (2):

[0018]

[0019] Where x is 2, 3 or 4; U represents a polymer chain containing an imide repeating unit; R is selected from one or more of substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms or substituted or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from substituted or unsubstituted aryl groups having 6 to 30 carbon atoms or substituted or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

[0020] Optionally, each U has a straight-chain or branched structure, and the average degree of polymerization of each U is 1 to 10.

[0021] Optionally, the imide repeating unit is selected from one or more of aliphatic imides, semi-aromatic imides, and aromatic imides.

[0022] Optionally, the imide repeating unit has the structure shown in formula (3):

[0023]

[0024] in R1 represents a connecting bond, and is selected from substituted or unsubstituted alkylene groups having 1 to 12 carbon atoms, substituted or unsubstituted aryl groups having 6 to 36 carbon atoms, or substituted or unsubstituted heteroaryl groups having 2 to 24 carbon atoms.

[0025] Optionally, U comprises a polyimide first structural unit as shown in formula (4-1):

[0026]

[0027] in The linking bond used in formula (4-1) to connect with the N atom in formula (2); m1 is an integer selected from 1 to 10; each R1 may be the same or different; R3 is selected from substituted or unsubstituted alkylene with 1 to 12 carbon atoms, substituted or unsubstituted arylene with 6 to 36 carbon atoms, or substituted or unsubstituted heteroarylene with 2 to 24 carbon atoms.

[0028] Optionally, U includes a second structural unit as shown in equation (4-2):

[0029]

[0030] in The linking bond used in formula (4-2) to connect with the N atom in formula (2); m2 is an integer selected from 1 to 10; each R1 may be the same or different; R3 is selected from substituted or unsubstituted alkylene with 1 to 12 carbon atoms, substituted or unsubstituted arylene with 6 to 36 carbon atoms, or substituted or unsubstituted heteroarylene with 2 to 24 carbon atoms.

[0031] Alternatively, the structural formula of the polyimide compound is shown in formula (5-1):

[0032]

[0033] Where m1 is selected from integers from 2 to 5.

[0034] Alternatively, the structural formula of the polyimide compound is shown in formula (5-2):

[0035]

[0036] Where m2 is selected from integers from 2 to 5.

[0037] Optionally, each R1 and each R3 may be the same or different, and each may be independently selected from methylene, n-butylene, phenyl or diphenyl ether group;

[0038] Each R2 is independently selected from either phenylene or biphenylene.

[0039] The fourth aspect of this disclosure provides a method for preparing polyimide compounds, comprising the following steps:

[0040] The silicon-containing acid anhydride compound described in the first aspect of this disclosure is brought into contact with a polyamine monomer and a polyanion monomer to carry out a polycondensation reaction;

[0041] The polycondensation product is contacted with an imidization catalyst to carry out an imidization reaction.

[0042] Optionally, the polycondensation reaction includes: alternatingly contacting the polyamine monomer and the polyanhydride monomer with the silicon-containing anhydride compound to carry out multiple stepwise polycondensation reactions; the stepwise polycondensation reaction is repeated 1 to 10 times.

[0043] Optionally, the polybasic acid anhydride monomer includes a dibasic acid anhydride monomer selected from one or more of the following: pyromellitic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-tetracarboxybenzophenone dianhydride, 3,3',4,4'-tetracarboxybiphenyl sulfone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylmethane dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride.

[0044] Optionally, the polyacid anhydride monomer further includes a silicon-containing acid anhydride compound as shown in formula (1);

[0045] The first polyanhydride monomer introduced in the multiple step-growth polycondensation reaction is a silicon-containing anhydride compound as shown in formula (1).

[0046] Optionally, the polyamine monomer includes a diamine monomer selected from one or more of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,3-diamino-2-methylpropane, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenyl sulfone, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene.

[0047] Optionally, the conditions for the polycondensation reaction include: using solution polymerization, a reaction temperature of 25–180°C, a reaction time of 1–6 h, and a solvent selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0048] Optionally, during the multiple stepwise reactions, the molar ratio of the polyamine monomer to the silicon-containing anhydride compound added in a single step is 4.0 to 5.0:1; the molar ratio of the polyamine monomer to the silicon-containing anhydride compound added in a single step is 4.0 to 5.0:1.

[0049] Optionally, the conditions for the imidization reaction include: a reaction temperature of 80–180°C, a reaction time of 1–6 h, and a molar ratio of the polycondensation product to the imidization catalyst of 1:0.01–1.

[0050] The iminolation catalyst is selected from one or more of isoquinoline, pyridine, and acetic anhydride.

[0051] This disclosure provides, in its fifth aspect, a polyimide compound prepared according to the method described in the fourth aspect of this disclosure.

[0052] This sixth aspect of the disclosure provides the use of the polyimide compounds described in the third or fifth aspects of the disclosure in filled polyamic acid.

[0053] Through the above technical solutions, this disclosure provides a silicon-containing acid anhydride compound and its preparation method, as well as a polyimide compound and its preparation method and application. The silicon-containing acid anhydride compound can be used as a starting material for preparing polyimide compounds. This silicon-containing acid anhydride compound has multiple acid anhydride structures (two or more), and can prepare silicon-containing polyimide compounds with two or more branches. Furthermore, the presence of silicon in the polyimide compound reduces its dielectric constant. The polyimide compound provided by this disclosure overcomes the drawbacks of existing polyimide fillers, such as insolubility, infusibility, or the need for esterification reactions to modify and reduce performance. Unlike general organic fillers, the polyimide compound provided by this disclosure does not reduce the heat resistance and dielectric properties of polyimide when used as a filler. The polyimide compound can crosslink ammonium acid solution, resulting in better mechanical properties. At the same time, as a small molecule filler, this polyimide compound does not significantly affect the viscosity of polyammonium acid, maintaining almost no change in viscosity.

[0054] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0055] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0056] The first aspect of this disclosure provides a silicon-containing acid anhydride compound, the structure of which is shown in the following formula (1):

[0057]

[0058] Where x is selected from 2, 3 or 4; R is selected from one or more of substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms or substituted or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from substituted or unsubstituted aryl groups having 6 to 30 carbon atoms or substituted or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

[0059] The first aspect of this disclosure provides a silicon-containing anhydride compound that can be used as a starting material for preparing polyimide compounds. The silicon-containing anhydride compound has multiple anhydride structures (two or more) and can be used to prepare silicon-containing polyimide compounds with two or more branches. The presence of silicon in the polyimide compound can reduce its dielectric constant.

[0060] In one embodiment, the silicon-containing anhydride compound has the structure shown in formula (1-1):

[0061]

[0062] R2 is selected from phenylene or biphenylene. In this disclosure, the silicon-containing anhydride compound preferably has four anhydride groups, enabling the preparation of polyimide compounds with four branches when used as a starting material. Furthermore, the presence of rigid groups (e.g., benzene rings) in the silicon-containing anhydride compound provided in this disclosure is also advantageous for improving the mechanical properties of polyimides when used as fillers.

[0063] The second aspect of this disclosure provides a method for preparing the silicon-containing acid anhydride compound described in the first aspect of this disclosure, comprising the following steps:

[0064] S101. The first reactant is reacted with an organic acid and an anhydride; wherein the structure of the first reactant is shown in formula (1-2):

[0065] In this embodiment, a solid product is obtained by recrystallizing the reaction product in an organic acid.

[0066] In one embodiment, the organic acid is selected from one or more of acetic acid and trifluoroacetic acid; the acid anhydride is acetic anhydride;

[0067] The molar ratio of the first reactant to the organic acid and acid anhydride is 1:0.5 to 3:0.5 to 3.

[0068] In one embodiment, the reaction conditions include: under reflux heating, the reaction temperature is 60–120°C and the reaction time is 4–24 h; preferably, under reflux heating, the reaction temperature is 70–90°C and the reaction time is 4–10 h.

[0069] In this disclosure, the first reactant can be obtained through ordinary commercial channels or prepared by known methods.

[0070] In a preferred embodiment, the first reactant can be prepared by a method comprising the following steps:

[0071] S102. The second reactant is hydrolyzed in an alkaline solution; wherein the structure of the second reactant is shown in formula (1-3) below:

[0072] In this embodiment, a solid product is obtained by recrystallizing the hydrolysis product in an organic acid.

[0073] In one embodiment, the alkaline solution is selected from one or more of potassium hydroxide solution and sodium hydroxide; optionally, the mass concentration of the alkaline solution is 5-15% by weight. Preferably, the ratio of the second reactant to the alkaline solution is 1:1-20, more preferably 1:5-10.

[0074] In one embodiment, the conditions for the hydrolysis reaction include: a reaction temperature of 25–100°C and a reaction time of 4–24 h; preferably, the reaction temperature is 45–85°C and the reaction time is 4–12 h.

[0075] In this disclosure, the second reactant can be obtained through ordinary commercial channels or prepared by known methods.

[0076] In a preferred embodiment, the second reactant can be prepared by a method comprising the following steps:

[0077] S103. The third reactant is reacted with 4-nitrophthalonitrile in an organic solution; wherein the structure of the third reactant is shown in formula (1-4) below:

[0078] In this embodiment, the second reactant can be obtained by purification using column chromatography.

[0079] In one embodiment, the molar ratio of the third reactant to 4-nitrophthalonitrile is 1:4 to 5, preferably 1:4 to 4.5.

[0080] In one embodiment, the reaction conditions between the third reactant and 4-nitrophthalonitrile include: a reaction temperature of 60–120°C and a reaction time of 2–24 h; preferably, the reaction temperature is 80–120°C and the reaction time is 4–12 h.

[0081] In this disclosure, the third reactant can be obtained through ordinary commercial channels or prepared by known methods.

[0082] In one specific embodiment, a silicon-containing acid anhydride compound is synthesized through the following steps, as shown in the following synthetic reaction formula:

[0083]

[0084] (1) Four times the amount of 4-methoxybromobenzene and four times the amount of magnesium powder were reacted under the initiation of a catalytic amount of iodine to prepare a Grignard reagent. One times the amount of silicon tetrachloride, tetramethoxysilane, or tetraethoxysilane was added dropwise in an ice-water bath. After reacting overnight, the reaction was quenched with a saturated ammonium chloride solution. After extraction with ethyl acetate, the organic phase was dried with anhydrous sodium sulfate and concentrated to obtain compound 1.

[0085] (2) Compound 1 was added to excess acetic acid and 48% hydrobromic acid and stirred under reflux for 12 hours. The reaction was then cooled to room temperature and extracted with ethyl acetate. The organic phase was removed and 10% sodium hydroxide solution was slowly added dropwise to separate the aqueous phase. The aqueous phase was washed three times with dichloromethane, the aqueous phase solution was adjusted to acidity, and filtered to obtain compound 2 (the third reactant).

[0086] (3) Dissolve one-times amount of compound 2 and two-times amount of 4-nitrophthalonitrile in N,N-dimethylformamide, heat to 100 degrees and react for 5 hours. After cooling the reaction to room temperature, purify by column chromatography to obtain compound 3 (second reactant).

[0087] (4) Compound 3 was dissolved in a 10% potassium hydroxide solution for hydrolysis. After reacting for 10 hours, it was recrystallized with glacial acetic acid to obtain compound 4 (the first reactant).

[0088] (5) Compound 5 was dissolved in a mixed solution of acetic acid and acetic anhydride in 20 times its volume and reacted. After heating under reflux for 24 hours, the mixture was recrystallized from glacial acetic acid to obtain compound 5 (a silicon-containing anhydride compound). The added multiples are calculated in molar amounts.

[0089] The chemical structure of compound 5 (a silicon-containing anhydride compound) was determined by nuclear magnetic resonance (NMR) spectroscopy.

[0090] A third aspect of this disclosure provides a polyimide compound having the structure shown in formula (2):

[0091]

[0092] Where x is 2, 3 or 4; U represents a polymer chain containing an imide repeating unit; R is selected from one or more of substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms or substituted or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from substituted or unsubstituted aryl groups having 6 to 30 carbon atoms or substituted or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

[0093] This disclosure provides a polyimide compound containing silicon, which can reduce its dielectric constant. The polyimide compound provided by this disclosure overcomes the drawbacks of existing polyimide fillers, such as insolubility, infusibility, or the need for esterification reactions to alter their properties. Furthermore, unlike general organic fillers, the polyimide compound provided by this disclosure does not reduce the heat resistance or dielectric properties of polyimide when used as a filler. The polyimide compound can crosslink ammonium acid solutions, resulting in better mechanical properties. Simultaneously, as a small molecule filler, this polyimide compound does not significantly affect the viscosity of polyammonium acid, maintaining almost no change in viscosity.

[0094] In this disclosure, "imide repeating unit" refers to a repeating unit containing an imide ring on the main chain, obtained by polymerizing polyhydric anhydrides and polyamines. In this disclosure, the term "substituted or unsubstituted" refers to a group that may or may not have substituents, and the number of carbon atoms refers to the total number of carbon atoms in the group and its substituents. Substituents in this application can be of conventional types in the art, including but not limited to alkyl groups with 1 to 10 carbon atoms (e.g., methyl, ethyl, isopropyl, n-propyl, tert-butyl, etc.), alkoxy groups with 1 to 10 carbon atoms (e.g., methoxy, ethoxy, etc.), aryl groups with 6 to 18 carbon atoms (e.g., phenyl, naphthyl, biphenyl, etc.), and heteroaryl groups with 3 to 18 carbon atoms (e.g., pyridyl, pyrimidinyl, triazine, etc.).

[0095] In this disclosure, as can be seen from formula (2), two or more (3 or 4) "arms" are connected to the central Si atom, preferably a "multi-arm compound," forming a dendritic compound structure. In this polyimide compound structure, the structures on each "arm" may be the same or different, preferably the same. The same labeled groups (e.g., each R2) on each "arm" may be the same or different, preferably the same.

[0096] In a preferred embodiment, x is 4, that is, in a preferred case, the polyimide compound has 4 structurally identical "arms".

[0097] In one embodiment, each U has a straight-chain or branched structure, and the average degree of polymerization of each U is 1 to 10. In this disclosure, the average degree of polymerization of each U refers to the average number of imide repeating units contained in each arm.

[0098] In one embodiment, the imide repeating unit is selected from one or more of aliphatic imides, semi-aromatic imides, and aromatic imides.

[0099] In one embodiment, the imide repeating unit has the structure shown in formula (3):

[0100]

[0101] in R1 represents a connecting bond, and is selected from substituted or unsubstituted alkylene groups having 1 to 12 carbon atoms, substituted or unsubstituted aryl groups having 6 to 36 carbon atoms, or substituted or unsubstituted heteroaryl groups having 2 to 24 carbon atoms.

[0102] In a preferred embodiment, U comprises a polyimide first structural unit as shown in formula (4-1):

[0103]

[0104] in The linkage in formula (4-1) is used to connect with the N atom in formula (2); m1 is an integer selected from 1 to 10; each R1 may be the same or different; R3 is selected from substituted or unsubstituted alkylene groups with 1 to 12 carbon atoms, substituted or unsubstituted arylene groups with 6 to 36 carbon atoms, or substituted or unsubstituted heteroarylene groups with 2 to 24 carbon atoms. Specifically, m1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In this disclosure, the groups on each arm of the compound, such as R1, R2, and R3, may be the same or different from each other, preferably the same; furthermore, the value of m1 of U on each arm of the compound may be the same or different, preferably the same.

[0105] In one specific embodiment, the structural formula of the polyimide compound is shown in formula (5-1):

[0106]

[0107] Where m1 is selected from integers from 2 to 5. m1 can be selected from 2, 3, 4 or 5.

[0108] In another preferred embodiment, U comprises a second structural unit as shown in equation (4-2):

[0109]

[0110] in The linking bond in formula (4-2) is used to connect with the N atom in formula (2); m2 is an integer selected from 1 to 10; each R1 may be the same or different; R3 is selected from substituted or unsubstituted alkylene groups with 1 to 12 carbon atoms, substituted or unsubstituted arylene groups with 6 to 36 carbon atoms, or substituted or unsubstituted heteroarylene groups with 2 to 24 carbon atoms. Specifically, m2 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The polymer chain U provided in this embodiment further introduces Si atoms on each arm and draws three branches on the Si atoms. In this compound, the groups between each branch of each arm, such as R1, R2, and R3, may be the same or different from each other, preferably the same; furthermore, in this compound, the value of m2 of U between each branch of each arm may be the same or different, preferably the same.

[0111] In one specific embodiment, the structural formula of the polyimide compound is shown in formula (5-2):

[0112] Where m2 is selected from integers from 2 to 5. m2 can be selected from 2, 3, 4 or 5.

[0113] In one embodiment, in formula (4-1) or formula (4-2), each R1 and each R3 may be the same or different, and each is independently selected from methylene, n-butylene, phenyl or diphenyl ether group;

[0114] Each R2 is independently selected from either phenylene or biphenylene.

[0115] In one specific embodiment, the polyimide compound has a relative molecular weight of 2000 to 100000.

[0116] The fourth aspect of this disclosure provides a method for preparing polyimide compounds, comprising the following steps:

[0117] The silicon-containing acid anhydride compound described in the first aspect of this disclosure It undergoes a polycondensation reaction upon contact with polyamine monomers and polyanhydride monomers;

[0118] The polycondensation product is contacted with an imidization catalyst to carry out an imidization reaction.

[0119] This disclosure provides a method for preparing polyimide compounds, which uses a silicon-containing acid anhydride compound of formula (1) provided in the first aspect of this disclosure as a starting reactant and obtains a multi-arm polyimide compound through a polycondensation reaction of a polyamine monomer and a polyanhydride monomer.

[0120] In this disclosure, "multi-component" in "multi-amine monomers, multi-acid anhydride monomers" includes binary and above monomers.

[0121] In a preferred embodiment, the polycondensation reaction includes: alternately contacting the polyamine monomer and the polyanhydride monomer with the silicon-containing anhydride compound to perform multiple step-growth polycondensation reactions; the step-growth polycondensation reaction is repeated 1 to 10 times. In this disclosure, "introducing a polyamine and a polyanhydride once" is considered as one "repeated reaction," or it can be said that forming an "imide" structural unit on each arm of the compound is considered as one "repeated reaction." By controlling the alternating step-growth polycondensation reactions of the polyamine monomer and the polyanhydride monomer, this disclosure can effectively control the growth of structural units on each arm, ensuring that each step of the reaction is sufficient and complete, thereby controlling the formation of the same structure on each arm.

[0122] In one specific embodiment, the polybasic acid anhydride monomer includes a dibasic acid anhydride monomer, which is selected from one or more of the following: pyromellitic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-tetracarboxybenzophenone dianhydride, 3,3',4,4'-tetracarboxybiphenyl sulfone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylmethane dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride.

[0123] In a preferred embodiment, the polyacid anhydride monomer further includes a silicon-containing acid anhydride compound represented by formula (1);

[0124] The polyacid anhydride monomer introduced in the first stepwise polycondensation reaction is a silicon-containing anhydride compound as shown in formula (1). In this embodiment, the silicon-containing anhydride compound as shown in formula (1) is introduced in the first reaction, which can further introduce Si atoms and three branches on each arm. In the subsequent reaction process, polymer chains U can be formed on each branch on each arm through the stepwise polycondensation reaction, as shown in formulas (4-2) and (5-2), which further improves the branching degree of the filler molecular structure and improves the modification effect in polyamic acid solution.

[0125] In one embodiment, the polyamine monomer includes a diamine monomer selected from one or more of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,3-diamino-2-methylpropane, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenyl sulfone, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene.

[0126] In a preferred embodiment, the polyamine monomer is selected from one or more of 4,4'-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,3-diamino-2-methylpropane, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene.

[0127] In this disclosure, the polyamine monomers used in each step may be the same or different, but preferably the same.

[0128] In one embodiment, the conditions for the polycondensation reaction include: using solution polymerization, a reaction temperature of 25–180°C, preferably 45–120°C, a reaction time of 1–6 h, preferably 2–6 h, and a solvent selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0129] In one embodiment, during the multiple stepwise reactions, the molar ratio of the polyamine monomer to the silicon-containing anhydride compound added in each step is 4.0–5.0:1, preferably 4.0–4.5:1; the molar ratio of the polyamine monomer to the silicon-containing anhydride compound added in each step is 4.0–5.0:1, preferably 4.0–4.5:1. The molar amount of the silicon-containing anhydride compound is based on the molar amount of the silicon-containing anhydride compound added in the first step.

[0130] In one embodiment, the conditions for the imidization reaction include: a reaction temperature of 80–180°C and a reaction time of 1–6 h; the molar ratio of the polycondensation product to the imidization catalyst is 1:0.01–1, preferably 1:0.01–0.5.

[0131] The iminolation catalyst is selected from one or more of isoquinoline, pyridine, and acetic anhydride.

[0132] In one specific embodiment, the method for synthesizing the polyimide compound represented by formula (5-1) includes the following steps:

[0133] (1) The solvent, the aforementioned compound 5 (a silicon-containing acid anhydride compound), and the diamine are sequentially added into the reaction vessel 1, the stirring is turned on, the reaction vessel is controlled at 25-180°C, and the stirring is carried out for 1-6 hours.

[0134] (2) Add pyromellitic dianhydride and solvent into reaction vessel 2 and mix thoroughly. Slowly add the solution from reaction vessel 1 to reaction vessel 2 and continue stirring for 1 to 4 hours.

[0135] (3) Add the diamine and solvent into the reaction vessel 3 and mix thoroughly. Slowly add the solution from the reaction vessel 2 into the reaction vessel 3 and continue stirring for 1 to 4 hours.

[0136] (4) Repeat steps (2) to (3);

[0137] (5) Add the catalyst to the reactor, keep the reactor at 80-180°C, and stir for 1-6 hours.

[0138] (6) After cooling to room temperature, methanol is added, filtered, and dried to obtain polyimide comb dendrites.

[0139] In another specific embodiment, the method for synthesizing the polyimide compound represented by formula (5-2) includes the following steps:

[0140] (1) Add the solvent, compound 5 (silicon-containing acid anhydride compound), and diamine into the reaction vessel 1 in sequence, start stirring, control the reaction vessel at 25-180℃, and stir for 1-6 hours.

[0141] (2) Add compound 5 (silicon-containing acid anhydride compound) and solvent into reaction vessel 2 and mix thoroughly. Slowly add the solution in reaction vessel 1 to reaction vessel 2 and continue stirring for 1 to 4 hours.

[0142] (3) Add the diamine and solvent into the reaction vessel 3 and mix thoroughly. Slowly add the solution from the reaction vessel 2 into the reaction vessel 3 and continue stirring for 1 to 4 hours.

[0143] (4) Add pyromellitic dianhydride and solvent into reaction vessel 4 and mix thoroughly. Slowly add the solution from reaction vessel 3 into reaction vessel 4 and continue stirring for 1 to 4 hours.

[0144] (5) Add the diamine and solvent into the reaction vessel 5 and mix thoroughly. Slowly add the solution from the reaction vessel 4 into the reaction vessel 5 and continue stirring for 1 to 4 hours.

[0145] (6) Repeat steps (4) to (5).

[0146] (7) Add the catalyst to the reactor, keep the reactor at 80-180°C, and stir for 1-6 hours.

[0147] (8) After cooling to room temperature, methanol is added, filtered and dried to obtain polyimide comb dendrites.

[0148] In the above specific implementation, by controlling the slow dripping speed and sufficient reaction time, the reaction in each step is ensured to proceed fully, so as to control the identical structure of each arm and each branch chain on the arm.

[0149] This sixth aspect of the disclosure provides the use of the polyimide compounds described in the third or fifth aspects of the disclosure in filled polyamic acid.

[0150] When the polyimide compounds provided in this disclosure are used as fillers for polyamic acid solutions, the concentration of the polyimide compounds added is 1 to 80% by weight, preferably 5 to 50% by weight.

[0151] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0152] Preparation Example 1

[0153] This preparation example is used to synthesize tetrahydric monomer 1:

[0154] (1) 4 mol of 4-methoxybromobenzene and 4 mol of magnesium powder were reacted under the initiation of iodine to prepare a Grignard reagent. 1 mol of silicon tetrachloride was added dropwise in an ice-water bath, and the reaction was carried out at 25°C for 10 h. The reaction was then quenched with saturated ammonium chloride solution. After extraction with ethyl acetate, the organic phase obtained by extraction was dried with anhydrous sodium sulfate and concentrated to obtain compound 1 with R2 being phenyl.

[0155] (2) Compound 1 was added to excess acetic acid and 48% hydrobromic acid for a first hydrolysis reaction at 60°C for 12 hours. After the reaction was completed and cooled to room temperature, it was extracted with ethyl acetate. The organic phase was then removed and 10% sodium hydroxide solution was slowly added dropwise to separate the aqueous phase. The aqueous phase was washed three times with dichloromethane, and the pH was adjusted to 2 with hydrochloric acid. The mixture was then filtered to obtain compound 2, in which R2 is phenyl.

[0156] (3) 1 mol of compound 2 and 2 mol of 4-nitrophthalonitrile were dissolved in 20 mol of N,N-dimethylformamide, heated to 100°C and reacted for 5 hours. After cooling the reaction product to room temperature, compound 3 with R2 being phenyl was purified by column chromatography.

[0157] (4) Compound 3 was dissolved in a 10% by weight potassium hydroxide solution to carry out a second hydrolysis reaction. After reacting for 10 hours, the compound 4 with R2 being phenyl was obtained by recrystallization with glacial acetic acid.

[0158] (5) Compound 4 was dissolved in a mixed solution of acetic acid and acetic anhydride to carry out a dehydration reaction at a temperature of 80°C for 24 hours. The compound 5 with R2 being phenyl was obtained by recrystallization with glacial acetic acid. It was denoted as tetrahydric monomer 1 and its structural formula is shown below.

[0159]

[0160] The NMR data for tetrahydric monomer 1 are as follows: 1H NMR (500MHz, Chloroform-d) δ=8.03(d,J=8.1Hz,1H),7.55–7.49(m,3H),7.36(dd,J=8.0,1.9Hz,1H),6.87–6.81(m,2H).

[0161] Preparation Example 2

[0162] This preparation example is used to synthesize tetrahydric monomer 2:

[0163] (1) 4 mol of 4-bromo-4'-methoxybiphenyl reacted with 4 mol of magnesium powder under the initiation of iodine to prepare a Grignard reagent. 1 mol of tetraethoxysilane was added dropwise in an ice-water bath, and the reaction was carried out at 25°C for 10 h. The reaction was then quenched with saturated ammonium chloride solution. After extraction with ethyl acetate, the organic phase obtained by extraction was dried with anhydrous sodium sulfate and concentrated to obtain compound 1 with R2 as 4,4'-biphenyl.

[0164] (2) Compound 1 was added to excess acetic acid and 48% hydrobromic acid for a first hydrolysis reaction at 60°C for 12 hours. After the reaction was completed and cooled to room temperature, it was extracted with ethyl acetate. The organic phase was then removed and 10% sodium hydroxide solution was slowly added dropwise to separate the aqueous phase. The aqueous phase was washed three times with dichloromethane, and the pH was adjusted to 2 with hydrochloric acid. The mixture was then filtered to obtain compound 2 with R2 being 4,4'-biphenyl.

[0165] (3) 1 mol of compound 2 and 2 mol of 4-nitrophthalonitrile were dissolved in 20 mol of N,N-dimethylformamide, heated to 100°C and reacted for 5 hours. After the reaction product was cooled to room temperature, it was purified by column chromatography to obtain compound 3 with R2 as 4,4'-biphenyl.

[0166] (4) Compound 3 was dissolved in a 10% by weight potassium hydroxide solution to carry out a second hydrolysis reaction. After reacting for 10 hours, the compound 4 with R2 being 4,4'-biphenyl was obtained by recrystallization with glacial acetic acid.

[0167] (5) Compound 4 was dissolved in a mixed solution of acetic acid and acetic anhydride to carry out a dehydration reaction at a temperature of 80°C for 24 hours. The compound 5 with R2 being 4,4'-biphenyl was obtained by recrystallization with glacial acetic acid. It was denoted as tetrahydric monomer 2 and its structural formula is shown below.

[0168]

[0169] The NMR data for tetrahydric monomer 2 are as follows: 1H NMR (500MHz, Chloroform-d) δ 8.03 (d, J = 8.1Hz, 1H), 7.74–7.66 (m, 4H), 7.54–7.48 (m, 3H), 7.36 (dd, J = 8.0, 2.6Hz, 1H), 7.20–7.14 (m, 2H).

[0170] Example 1

[0171] This embodiment is used to synthesize dendrite 1:

[0172] (1) The solvent (N,N-dimethylacetamide), the final product of Preparation Example 1 (tetrahydride monomer 1), and 4,4'-diaminodiphenyl ether (diamine) were sequentially added into the reaction vessel 1. The molar ratio of diamine to tetrahydride monomer 1 was 2:1. Stirring was started, and the reaction vessel was controlled at 45°C for 2 hours.

[0173] (2) Add pyromellitic dianhydride (dicarboxylic acid anhydride) into reactor 2 and mix thoroughly. Slowly add the solution in reactor 1 to reactor 2 dropwise. The molar ratio of pyromellitic dianhydride to tetrahydric monomer 1 is 4:1. Continue stirring for 2 hours.

[0174] (3) Add 4,4'-diaminodiphenyl ether (diamine) into reactor 3 and mix thoroughly. Slowly add the solution in reactor 2 to reactor 3 dropwise. The molar ratio of diamine to tetrahydric monomer 1 is 4:1. Continue stirring for 2 hours.

[0175] (4) Repeat steps (2) and (3) twice.

[0176] (5) Add the catalyst (isoquinoline catalyst) to the reactor. The molar ratio of the polycondensation product to the imidization catalyst is 1:0.1. Control the reactor at 120°C and stir for 4 hours.

[0177] (6) After cooling to room temperature, methanol is added, filtered and dried to obtain polyimide dendritic material, the structure of which is shown below.

[0178]

[0179] According to GPC testing, the relative molecular mass of this polyimide dendritic is 6308.11.

[0180] Example 2

[0181] This embodiment is used to synthesize dendrite 2:

[0182] (1) The solvent (N,N-dimethylacetamide), the final product of Preparation Example 1 (tetrahydride monomer 1), and 4,4'-diaminodiphenyl ether were sequentially added into the reaction vessel 1. The molar ratio of diamine to tetrahydride monomer 2 was 2:1. Stirring was started, and the reaction vessel was controlled at 25°C for 4 hours.

[0183] (2) The final product of Preparation Example 1 (tetrahydride monomer 1) and the solvent (N,N-dimethylacetamide) were put into the reaction vessel 2 and mixed thoroughly. The solution in the reaction vessel 1 was slowly added dropwise to the reaction vessel 2. The molar ratio of tetrahydride monomer 2 in step (2) to tetrahydride monomer 2 in step (1) was 4:1. Stirring was continued for 4 hours.

[0184] (3) Add 4,4'-diaminodiphenyl ether into reactor 3 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 from step (1) is 4:1. Slowly add the solution from reactor 2 to reactor 3 and continue stirring for 4 hours.

[0185] (4) Add pyromellitic dianhydride into reaction vessel 4 and mix thoroughly. The molar ratio of pyromellitic dianhydride to tetrahydric monomer 2 in step (1) is 4:1. Slowly add the solution in reaction vessel 3 to reaction vessel 4 and continue stirring for 4 hours.

[0186] (5) Add 4,4'-diaminodiphenyl ether into reactor 5 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 from step (1) is 4:1. Slowly add the solution from reactor 4 to reactor 5 and continue stirring for 4 hours.

[0187] (6) Repeat steps (4) and (5) twice.

[0188] (7) Add the catalyst (isoquinoline catalyst) to the reactor. The molar ratio of the polycondensation product to the imidization catalyst is 1:0.1. Control the reactor at 120°C and stir for 4 hours.

[0189] (8) After cooling to room temperature, methanol is added, filtered and dried to obtain polyimide comb dendrites, the structure of which is shown below.

[0190]

[0191] According to GPC testing, the relative molecular mass of this polyimide dendritic is 22580.11.

[0192] Example 3

[0193] This embodiment is used to synthesize dendrite 3:

[0194] (1) The solvent (N,N-dimethylacetamide), the final product of Preparation Example 2 (tetrahydride monomer 2), and 4,4'-diaminodiphenyl ether were sequentially added into the reaction vessel 1. The molar ratio of diamine to tetrahydride monomer 2 was 2:1. Stirring was started, and the reaction vessel was controlled at 60°C for 2 hours.

[0195] (2) The final product of Preparation Example 2 (tetrahydride monomer 2) and the solvent (N,N-dimethylacetamide) were put into the reaction vessel 2 and mixed thoroughly. The solution in the reaction vessel 1 was slowly added dropwise to the reaction vessel 2. The molar ratio of tetrahydride monomer 2 in step (2) to tetrahydride monomer 2 in step (1) was 4:1. Stirring was continued for 4 hours.

[0196] (3) Add 4,4'-diaminodiphenyl ether into reactor 3 and mix thoroughly. Slowly add the solution in reactor 2 to reactor 3. The molar ratio of diamine to tetrahydric monomer 2 in step (1) is 4:1. Continue stirring for 2 hours.

[0197] (4) Add pyromellitic dianhydride into reaction vessel 4 and mix thoroughly. Slowly add the solution in reaction vessel 3 to reaction vessel 4. The molar ratio of pyromellitic dianhydride to tetrahydric monomer 2 in step (1) is 4:1. Continue stirring for 2 hours.

[0198] (5) Add 4,4'-diaminodiphenyl ether and solvent into reactor 5 and mix thoroughly. Slowly add the solution in reactor 4 into reactor 5. The molar ratio of diamine to tetrahydric monomer 2 in step (1) is 4:1. Continue stirring for 2 hours.

[0199] (6) Repeat steps (4) and (5) twice.

[0200] (7) Add the catalyst (isoquinoline catalyst) to the reactor. The molar ratio of the polycondensation product to the imidization catalyst is 1:0.2. Control the reactor at 80°C and stir for 8 hours.

[0201] (8) After cooling to room temperature, methanol is added, filtered and dried to obtain polyimide comb dendrites, the structure of which is shown below.

[0202]

[0203] According to GPC testing, the relative molecular mass of the polyimide dendritic is 22932.24.

[0204] Example 4

[0205] This embodiment is used to synthesize dendrite 4:

[0206] (1) The solvent (N,N-dimethylacetamide), the final product of Preparation Example 2 (tetrahydride monomer 2), and 4,4'-diaminodiphenyl ether were sequentially added into the reaction vessel 1. The molar ratio of diamine to tetrahydride monomer 2 was 2:1. Stirring was started, and the reaction vessel was controlled at 25°C for 6 hours.

[0207] (2) The final product of Preparation Example 2 (tetrahydride monomer 2) and the solvent (N,N-dimethylacetamide) were put into the reaction vessel 2 and mixed thoroughly. The solution in the reaction vessel 1 was slowly added dropwise to the reaction vessel 2. The molar ratio of tetrahydride monomer 2 in step (2) to tetrahydride monomer 2 in step (1) was 4:1. Stirring was continued for 1 hour.

[0208] (3) Add 4,4'-diaminodiphenyl ether into reactor 3 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 in step (1) is 4:1. Slowly add the solution in reactor 2 to reactor 3 and continue stirring for 3 hours.

[0209] (4) Add pyromellitic dianhydride into reaction vessel 4 and mix thoroughly. The molar ratio of pyromellitic dianhydride to tetrahydric monomer 2 in step (1) is 4:1. Slowly add the solution in reaction vessel 3 to reaction vessel 4 and continue stirring for 3 hours.

[0210] (5) Add 4,4'-diaminodiphenyl ether into reactor 5 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 in step (1) is 4:1. Slowly add the solution in reactor 4 to reactor 5 and continue stirring for 3 hours.

[0211] (6) Repeat steps (4) and (5) 8 times.

[0212] (7) Add the catalyst (pyridine catalyst) to the reactor. The molar ratio of the polycondensation product to the imidization catalyst is 1:0.2. Control the reactor at 120°C and stir for 4 hours.

[0213] (8) After cooling to room temperature, methanol is added, filtered and dried to obtain polyimide comb dendrites, the structure of which is shown below.

[0214]

[0215] According to GPC testing, the relative molecular mass of this polyimide dendritic is 50436.47.

[0216] Example 5

[0217] This embodiment is used to synthesize dendrite 5:

[0218] (1) The solvent (N,N-dimethylacetamide), the final product of Preparation Example 2 (tetrahydride monomer 2), and p-phenylenediamine were sequentially added into the reaction vessel 1. The molar ratio of diamine to tetrahydride monomer 2 was 2.1:1. Stirring was started, and the reaction vessel was controlled at 85°C for 2 hours.

[0219] (2) The final product of Preparation Example 2 (tetrahydride monomer 2) is added into the reaction vessel 2 and mixed thoroughly. The molar ratio of tetrahydride monomer 2 in step (2) to tetrahydride monomer 2 in step (1) is 4:1. The solution in the reaction vessel 1 is slowly added dropwise to the reaction vessel 2 and stirred for 4 hours.

[0220] (3) Add p-phenylenediamine into reactor 3 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 is 4:1. Slowly add the solution in reactor 2 to reactor 3 and continue stirring for 4 hours.

[0221] (4) Add pyromellitic dianhydride into reaction vessel 4 and mix thoroughly. Slowly add the solution from reaction vessel 3 to reaction vessel 4. The molar ratio of pyromellitic dianhydride to tetrahydric monomer 2 is 4:1. Continue stirring for 4 hours.

[0222] (5) Add p-phenylenediamine into reactor 5 and mix thoroughly. The molar ratio of diamine to tetrahydric monomer 2 is 4:1. Slowly add the solution in reactor 4 to reactor 5 and continue stirring for 4 hours.

[0223] (6) Repeat steps (4) and (5) twice.

[0224] (7) Add the catalyst (isoquinoline catalyst) to the reactor. The molar ratio of the polycondensation product to the imidization catalyst is 1:0.5. Control the reactor at 80°C and stir for 6 hours.

[0225] (8) After cooling to room temperature, methanol was added, and the mixture was filtered and dried to obtain a polyimide dendritic compound, the structural formula of which is shown below.

[0226]

[0227] According to GPC testing, the relative molecular mass of this polyimide dendritic is 19908.61.

[0228] Example 6

[0229] This embodiment is used to synthesize dendrite 6:

[0230] This embodiment follows the preparation method described in Example 1, except that it uses 1,4-butanediamine and pyromellitic dianhydride; the rest of the process is the same as in Example 1. Polyimide comb-like dendrite 6 is obtained, and its structural formula is shown below.

[0231]

[0232] According to GPC testing, the relative molecular mass of this polyimide dendritic is 4592.34.

[0233] Comparative Example 1

[0234] (1) Add 20.00g of 4,4'-diaminodiphenyl ether and 105g of N,N-dimethylformamide into the reactor in sequence, start stirring, and cool down to 0℃.

[0235] (2) Add 24.96g of pyromellitic dianhydride slowly into the reactor over 4 hours.

[0236] (3) Heat the reactor to 70°C, keep it at that temperature for 2 hours, and then cool it to room temperature to obtain varnish (polyamic acid solution).

[0237] Example 7

[0238] (1) The dendritic material of Example 1 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0239] Example 8

[0240] (1) The dendritic material of Example 2 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0241] Example 9

[0242] The dendritic material from Example 3 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0243] Example 10

[0244] The dendritic material from Example 4 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0245] Example 11

[0246] The dendritic material from Example 5 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0247] Example 12

[0248] The dendritic material from Example 5 was added to the varnish of Comparative Example 1 at a mass fraction of 1%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0249] Example 13

[0250] The dendritic material from Example 5 was added to the varnish of Comparative Example 1 at a mass fraction of 10%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0251] Example 14

[0252] The dendritic material from Example 6 was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the mixture was stirred for 1 hour to obtain the modified varnish.

[0253] Comparative Example 2

[0254] (1) Epoxy crosslinking agent 1922A was added to the varnish of Comparative Example 1 at a mass fraction of 5%, and the modified varnish was obtained after stirring for 1 hour.

[0255] Test Example 1

[0256] This test example was used to perform infrared spectroscopy tests on the monomers obtained in Preparation Examples 1-2 and the polyimide fillers prepared in Examples 1-6. The test results are listed in Table 1 below.

[0257] Table 1 Infrared Data

[0258]

[0259] According to the infrared data in Table 1 above, we can see that:

[0260] The infrared spectra of the monomers obtained in Preparation Example 1 and Preparation Example 2 have a wavenumber of 1100 cm⁻¹. -1 The nearby Si-C characteristic peaks, and the wavenumber of 1820 cm⁻¹ -1 The carbonyl characteristic peaks of nearby acid anhydrides indicate that the obtained product has the corresponding acid anhydride structure.

[0261] The infrared spectra of the products obtained in Examples 1 to 5 are in the range of wavenumbers 2900 to 3200 cm⁻¹. -1 It has characteristic peaks of COOH and NH2 nearby; at a wavenumber of 1660 cm⁻¹ -1 The vicinity exhibits amide characteristic peaks; at a wavenumber of 1550 cm⁻¹ -1 The vicinity exhibits C-NH bending vibrations; at a wavenumber of 1780 cm⁻¹ -1 The presence of imide characteristic peaks nearby indicates that the obtained product has an imide structure. Example 6, in addition to containing the above characteristics, has a peak at 2930 cm⁻¹. -1 The presence of methylene peaks nearby indicates that the obtained product has an imide structure.

[0262] Test Example 2

[0263] This test example is used to test the performance of the varnish in the comparative example and the embodiment.

[0264] Breakdown strength: tested according to ASTM D149-97a standard;

[0265] Dielectric constant: Tested according to ASTM D150-18 standard;

[0266] Film-forming property testing: A wet film of the corresponding solution was prepared by coating and casting on a clean glass plate. The wet film was transferred to an oven and imidized according to the following heating program: 80℃ for 2 hours; 120℃ for 1 hour; 160℃ for 1 hour; 180℃ for 1 hour; 240℃ for 1 hour; 280℃ for 1 hour; 350℃ for 1 hour, with a heating rate of 2℃ / min. After the glass plate cooled to room temperature, the glass plate coated with the polyimide film was immersed in deionized water to peel it off, finally obtaining the corresponding self-supporting PI film.

[0267] Among these criteria, a film that forms a single sheet on the glass, with no cracks on the surface and remains intact after peeling, is considered to have excellent film formation. A film that forms a single sheet on the glass, with no cracks on the surface but not remaining intact after peeling, is considered to have average film formation. A film that forms fragments on the glass is considered to have failed to form a film.

[0268] Viscosity measurement: The viscosity was measured using a rotational viscometer in accordance with GB / T 9751-1998 standard;

[0269] Elongation at break: Tested according to GB / T1040.3-2006 standard;

[0270] 5% decomposition temperature: Tested according to GB / T37631 standard.

[0271] The performance test results are listed in Table 2 below.

[0272] Table 2 Performance Test Results

[0273]

[0274]

[0275] As can be seen from the data in Table 2 above:

[0276] Using the varnish (polyamic acid solution) obtained in Comparative Example 1 as a benchmark, in Comparative Example 2, a common commercially available epoxy crosslinking agent was added to the varnish. The elongation at break and breakdown strength were lower, the dielectric constant was higher, the film-forming effect was average, and the viscosity of the system increased significantly. The 5% decomposition temperature was lower than that of Comparative Example 1, indicating that the effect of using a common crosslinking agent to improve mechanical properties is weak, and the dielectric and heat resistance properties are poor. The film-forming effect is average, and the viscosity of the varnish is also increased.

[0277] In Examples 7-14, the silicon-containing polyimide compounds provided in this disclosure were used as fillers. The elongation at break, breakdown strength and 5% decomposition temperature were higher than those of Comparative Example 2, the dielectric constant and viscosity were lower than those of Comparative Example 2, the viscosity was close to that of the varnish of Comparative Example 1, and it also had very good film-forming properties.

[0278] Comparing Examples 11 to 13, it can be seen that, using the same dendritic compound obtained in Example 5, the amount of dendritic compound added in Examples 11 and 13 is in the range of "5 to 50% by weight". Compared with Example 12 (where the amount of dendritic compound added is only 1% by weight), Examples 11 and 13 have higher elongation at break, breakdown strength and higher 5% decomposition temperature.

[0279] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0280] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0281] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A silicon-containing acid anhydride compound, characterized in that, The structure of the silicon-containing anhydride compound is shown in the following formula (1): Equation (1); Where x is 4; R is selected from one or more of unsubstituted alkyl groups having 1 to 12 carbon atoms or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from unsubstituted aryl groups having 6 to 30 carbon atoms or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

2. The silicon-containing acid anhydride compound according to claim 1, characterized in that, The structure of the silicon-containing anhydride compound is shown in the following formula (1-1): Equation (1-1); R2 is selected from phenylene or biphenylene.

3. A method for preparing the silicon-containing acid anhydride compound as described in claim 1 or 2, characterized in that, Includes the following steps: The first reactant is reacted with an organic acid and an anhydride; wherein the structure of the first reactant is shown in formula (1-2): Equation (1-2).

4. The method according to claim 3, characterized in that, The organic acid is selected from one or more of acetic acid and trifluoroacetic acid; the acid anhydride is acetic anhydride; the molar ratio of the first reactant to the organic acid and acid anhydride is 1:0.5~3:0.5~3.

5. The method according to claim 3, characterized in that, The reaction conditions include: under reflux heating, the reaction temperature is 60~120℃, and the reaction time is 4~24h.

6. A polyimide compound, characterized in that, The polyimide compound has the structure shown in formula (2): Equation (2); Where x is 4; U represents a polymer chain containing an imide repeating unit; R is selected from one or more of unsubstituted alkyl groups having 1 to 12 carbon atoms or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from unsubstituted aryl groups having 6 to 30 carbon atoms or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

7. The polyimide compound according to claim 6, characterized in that, Each U can be a straight chain or a branched chain structure.

8. The polyimide compound according to claim 6, characterized in that, The repeating unit of the imide is selected from one or more of aliphatic imides, semi-aromatic imides, and aromatic imides.

9. The polyimide compound according to claim 6, characterized in that, The imide repeating unit has the structure shown in formula (3): Equation (3); in" " indicates a connecting bond, and R1 is selected from unsubstituted alkylene groups with 1 to 12 carbon atoms, unsubstituted aryl groups with 6 to 36 carbon atoms, or unsubstituted heteroaryl groups with 2 to 24 carbon atoms.

10. The polyimide compound according to claim 9, characterized in that, U comprises the first polyimide structural unit shown in formula (4-1): Equation (4-1); in The connecting bond used in formula (4-1) to connect with the N atom in formula (2); m1 is an integer selected from 1 to 10; each R1 is the same or different; R3 is selected from unsubstituted alkylene with 1 to 12 carbon atoms, unsubstituted aryl with 6 to 36 carbon atoms, or unsubstituted heteroaryl with 2 to 24 carbon atoms.

11. The polyimide compound according to claim 9, characterized in that, U contains the second structural unit shown in equation (4-2): Equation (4-2); in The connecting bond used in formula (4-2) to connect with the N atom in formula (2); m2 is an integer selected from 1 to 10; each R1 is the same or different; R3 is selected from unsubstituted alkylene with 1 to 12 carbon atoms, unsubstituted aryl with 6 to 36 carbon atoms, or unsubstituted heteroaryl with 2 to 24 carbon atoms.

12. The polyimide compound according to claim 10, characterized in that, The structural formula of the polyimide compound is shown in formula (5-1): Equation (5-1); Where m1 is selected from integers from 2 to 5.

13. The polyimide compound according to claim 11, characterized in that, The structural formula of the polyimide compound is shown in formula (5-2): Equation (5-2); Where m2 is selected from integers from 2 to 5.

14. The polyimide compound according to claim 10 or 11, characterized in that, Each R1 and each R3 may be the same or different, and each is independently selected from methylene, n-butylene, phenyl or diphenyl ether group; Each R2 is independently selected from either phenylene or biphenylene.

15. A method for preparing polyimide compounds, characterized in that, Includes the following steps: Silicon-containing acid anhydride compounds are brought into contact with polyamine monomers and polyanion monomers to carry out a polycondensation reaction; The polycondensation product is contacted with an imidization catalyst to carry out an imidization reaction; The structure of the silicon-containing anhydride compound is shown in the following formula (1): Equation (1); Where x is 4; R is selected from one or more of unsubstituted alkyl groups having 1 to 12 carbon atoms or unsubstituted aryl groups having 6 to 30 carbon atoms; each R2 may be the same or different, and each is independently selected from unsubstituted aryl groups having 6 to 30 carbon atoms or unsubstituted heteroaryl groups having 2 to 30 carbon atoms.

16. The method according to claim 15, characterized in that, The structure of the silicon-containing anhydride compound is shown in the following formula (1-1): Equation (1-1); R2 is selected from phenylene or biphenylene.

17. The method according to claim 15, characterized in that, The silicon-containing anhydride compound is prepared by a method comprising the following steps: The first reactant is reacted with an organic acid and an anhydride; wherein the structure of the first reactant is shown in formula (1-2): Equation (1-2).

18. The method according to claim 17, characterized in that, The organic acid is selected from one or more of acetic acid and trifluoroacetic acid; the acid anhydride is acetic anhydride; the molar ratio of the first reactant to the organic acid and acid anhydride is 1:0.5~3:0.5~3.

19. The method according to claim 17, characterized in that, The reaction conditions include: under reflux heating, the reaction temperature is 60~120℃, and the reaction time is 4~24h.

20. The method according to claim 15, characterized in that, The polycondensation reaction includes: alternatingly contacting the polyamine monomer and the polyanhydride monomer with the silicon-containing anhydride compound to carry out multiple stepwise polycondensation reactions; the stepwise polycondensation reaction is repeated 1 to 10 times.

21. The method according to claim 20, characterized in that, The polybasic acid anhydride monomer includes a dibasic acid anhydride monomer selected from one or more of the following: pyromellitic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-tetracarboxybenzophenone dianhydride, 3,3',4,4'-tetracarboxybiphenyl sulfone dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylmethane dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride.

22. The method according to claim 21, characterized in that, The polyacid anhydride monomer also includes a silicon-containing acid anhydride compound as shown in formula (1); The first polyanhydride monomer introduced in the multiple step-condensation reactions is a silicon-containing anhydride compound as shown in formula (1).

23. The method according to claim 15, characterized in that, The polyamine monomer includes a diamine monomer selected from one or more of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 1,3-diamino-2-methylpropane, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenyl sulfone, N,N-bis(4-aminophenyl)-1,4-phenylenediamine, and 9,9-bis(4-aminophenyl)fluorene.

24. The method according to claim 15, characterized in that, The conditions for the polycondensation reaction include: solution polymerization, reaction temperature of 25~180℃, reaction time of 1~6h, and solvent selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

25. The method according to claim 20, characterized in that, During the aforementioned multiple step-condensation reactions, the molar ratio of the polyamine monomer to the silicon-containing anhydride compound added in a single step is 4.0~5.0:1; the molar ratio of the polyacid anhydride monomer to the silicon-containing anhydride compound added in a single step is 4.0~5.0:

1.

26. The method according to claim 15, characterized in that, The conditions for the imidization reaction include: a reaction temperature of 80~180℃, a reaction time of 1~6h; and a molar ratio of polycondensation product to imidization catalyst of 1:0.01~1. The iminolation catalyst is selected from one or more of isoquinoline, pyridine, and acetic anhydride.

27. The polyimide compound prepared by the method according to any one of claims 15 to 26.

28. The use of the polyimide compound according to any one of claims 6 to 14 and 27 in filled polyamic acid.

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