CN110373026B

CN110373026B - Polyimide resin composition, method for producing the same, and film

Info

Publication number: CN110373026B
Application number: CN201910823326.7A
Authority: CN
Inventors: 周浪; 陈玉净
Original assignee: Wuxi Chuangcai Optical Materials Co ltd
Current assignee: Wuxi Chuangcai Optical Materials Co ltd
Priority date: 2019-09-02
Filing date: 2019-09-02
Publication date: 2021-06-29
Anticipated expiration: 2039-09-02
Also published as: CN110373026A

Abstract

The present invention relates to a polyimide resin composition, a method for preparing the same, and a film, the composition comprising: inorganic particles, a polyimide resin, the inorganic particles being dispersed in the polyimide resin, and the surfaces of the inorganic particles being treated with a compound of the following general formula (I):

wherein R is₁And R₂The same or different, each independently selected from the group consisting of a C1-20 linear or branched alkyl group, a C5-20 cycloalkyl group, and a C6-30 aromatic group, wherein the alkyl, cycloalkyl, and aromatic groups may be substituted or contain heteroatoms, or R₁And R₂Are connected through a chemical bond.

Description

Polyimide resin composition, method for producing the same, and film

Technical Field

The present invention relates to the field of industrial production of heat conductive and insulating materials, and more particularly, to a heat conductive and insulating material comprising a resin composition of polyimide, and preparation and processing of a heat conductive and insulating film based on the composition.

Background

Polyimide (PI) is known as a gold polymer material, and is generally obtained by imidizing a dianhydride compound and a diamine compound under heating to dehydrate. Nowadays, various polyimide resins or polyimide-based compositions have been rapidly developed industrially, and industrial products obtained from these materials have been widely used in various fields such as inverter motors, military industry, aerospace, microelectronics, nano liquid crystals, separation membranes, and the like. In order to meet the application requirements of polyimide diversity, various polyimide composites have attracted much attention from the industry and from the scholars.

Polyimide products, such as polyimide films, are known to have good heat resistance, excellent mechanical properties, and chemical resistance. However, it is generally considered that various polyimide products are inferior in thermal conductivity. For example, the thermal conductivity of the conventional polyimide film is between 0.1 and 0.2W/m · K, and in order to improve the thermal conductivity of the polyimide film on the premise of ensuring the insulating property of the polyimide film, the current commercialized method is mainly to uniformly dope a thermal conductive filler including alumina, silica, silicon nitride, boron nitride and the like in resin to prepare a composite film. The polyimide composite film prepared by the method for uniformly doping the heat-conducting filler is difficult to form an effective heat-conducting channel when the filler doping amount is lower than 30 wt%, so that the heat-conducting property of the composite film is improved to a limited extent. Theoretically, the film can be endowed with high thermal conductivity by doping a large amount of thermal conductive filler, but the mechanical property and the insulating property of the film are greatly reduced because the filler in the film is easy to agglomerate.

In addition, although the strategy for improving the heat-conducting property and the insulating property of the polyimide composite material is to dope inorganic insulating particles, when the dosage of the inorganic heat-conducting filler dispersed in the resin is small, the filler is uniformly dispersed in the resin, but the filler cannot be contacted and interacted with each other, and the heat-conducting property is not greatly improved; when the amount of the filler is large, on one hand, the inorganic heat-conducting filler prevents the movement of molecular chains in the polymer, so that the toughness of the matrix is reduced; on the other hand, the crack between the inorganic heat-conducting filler and the matrix is expanded under the action of external load, so that the material is broken and fails. Therefore, although the heat conductivity of the film can be greatly improved by filling a large amount of the inorganic heat-conducting filler, the comprehensive performance of the film, especially the mechanical properties such as toughness and the like, is remarkably reduced, and the polyimide film is easy to crack and even cannot be cast and stretched to form the film.

In addition, when inorganic nanoparticles are doped in a large amount to improve the thermal conductivity of a polyimide film in practical use, there is also a problem of dispersion of the inorganic nanoparticles in a polyimide resin, and the inorganic nanoparticles are not uniformly dispersed in the polyimide resin due to a size effect, a surface effect, and the like of the inorganic nanoparticles, and the insulation property, mechanical properties, and the like of the polyimide-based composite material are also greatly reduced, thereby causing a problem of poor performance of the polyimide composite material doped with nanoparticles.

Citation 1 discloses a heat-conducting polyimide film, which consists of a polyimide matrix and an activated heat-conducting filler, wherein the mass fraction of the polyimide matrix is 78-98 wt%, and the mass fraction of the activated heat-conducting filler is 2-22 wt%; the activated heat-conducting filler is a filler subjected to surface treatment by a silane coupling agent. The obtained PI film has good thermal conductivity, and simultaneously keeps high mechanical property and good insulating property. On one hand, such surface treatment with an organosilane coupling agent may be limited to physical adsorption, and the improvement of the compatibility of inorganic particles and resin is relatively limited, and meanwhile, in order to obtain the optimal thermal conductivity, high thermal conductivity graphene is used in combination, and the two-dimensional large size of graphene is utilized to act as a bridge between aluminum nitride particles, however, in general, the graphene additionally used still has a concern of reducing the insulation.

Citation 2 relates to a high thermal conductivity polyimide film and a preparation method thereof, belongs to the technical field of polyimide films, and solves the problems that an efficient thermal conductivity channel is difficult to construct in the case of low filling amount of a thermal conductivity filler in the existing doping method, and the mechanical property and the thermal conductivity of the polyimide film cannot be compatible. The film comprises polyimide resin A, polyimide resin B and heat-conducting filler; the heat-conducting filler is dispersed in the phase A, and the difference value of the dissolving interaction parameters of the polyamic acid resin A and the polyamic acid resin B is 2.5-5.0; the heat conducting channels of the polyimide film are continuous and perpendicular to the plane of the film. Therefore, it is mainly directed to the case of filling with a lower inorganic filler in the polyimide resin.

Further, in reference 3, an attempt is made to improve the properties of the polyimide insulating film, such as thermal conductivity, heat resistance, chemical resistance and mechanical properties, by using an inorganic filler having a specific surface area. Cited document 4 discloses a thermally conductive inorganic spherical micron filler filled with a micron particle size as an inorganic filler; plate-like, rod-like, fibrous or scaly shaped micron filler; and a nanoparticle-sized thermally conductive inorganic nanofiller.

As can be seen, there is still room for improvement in the thermal conductivity of polyimide products, particularly polyimide films, using inorganic particles, inorganic fillers, and the like. In particular, there is still room for further investigation on how to improve the thermal conductivity of polyimide products while maintaining excellent insulation properties, mechanical properties, and the like.

Cited documents:

cited document 1: CN107652432A

Cited document 2: CN108610631A

Cited document 3: CN109155165A

Cited document 4: JP 2013-159748A

Disclosure of Invention

Problems to be solved by the invention

In view of the above problems in the prior art, the present invention is to solve the technical problem of how to effectively improve the thermal conductivity of a polyimide product, especially a polyimide film, when the thermal conductivity of the polyimide product is improved by using inorganic particles or inorganic fillers, and to obtain satisfactory thermal conductivity without reducing the insulation and mechanical properties of the polyimide product even when the filling amount of the inorganic particles or inorganic fillers is large.

In addition, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a polyimide film having improved thermal conductivity, which can prevent the occurrence of dispersion unevenness even when the polyimide film is filled with a large amount of inorganic particles or inorganic fillers of nanometer order.

Means for solving the problems

Through the intensive research of the applicant, the following technical scheme is found to be adopted to solve the technical problems:

[1] the present invention first provides a polyimide resin composition comprising:

an inorganic particle, wherein the inorganic particle is,

a polyimide resin,

the inorganic particles are dispersed in the polyimide resin, and the surfaces of the inorganic particles are treated with a compound of the following general formula (I):

wherein R is₁And R₂The alkyl, cycloalkyl and aromatic groups can be substituted or contain hetero atoms, or

R₁And R₂Are connected through a chemical bond.

[2] The polyimide resin composition according to [1], wherein the inorganic particles have an average particle diameter of 10 to 150nm, preferably 10 to 100 nm; the amount of the inorganic particles is 1-25% of the mass of the polyimide resin in the composition.

[3] The polyimide resin composition according to claim 1 or 2, wherein the inorganic particles are selected from one or more of a nitride, an oxide or a carbide of a metal, a semimetal, preferably a nitride, an oxide or a carbide of aluminum, silicon or boron.

[4]According to [1]]～[3]The polyimide resin composition described in any one of the above, wherein R is the compound of the general formula (I)₁And R₂At least one of them is selected from branched alkyl with 4-10 carbon atoms.

[5] The polyimide resin composition according to any one of [1] to [4], wherein the polyimide resin is prepared from a dibasic organic acid anhydride compound and a dibasic organic amine compound, and the molar ratio of the dibasic organic amine compound to the dibasic organic acid anhydride compound is 1:1 to 1.1: 1.

[6] Further, the present invention also provides a method for preparing a polyimide resin composition, comprising:

a step of surface-treating the inorganic particles with a compound of the general formula (I);

a step of preparing a polyamic acid solution;

a step of dispersing the surface-treated inorganic particles in the polyamic acid solution;

a step of imidizing the polyamic acid solution in which the inorganic particles are dispersed;

R₁And R₂Are connected through a chemical bond.

[7] The method according to [6], wherein the inorganic particles have an average particle diameter of 10 to 150nm, preferably 10 to 100 nm; the amount of the inorganic particles is 1-25% of the mass of the polyimide resin in the composition.

[8] The method according to [6] or [7], wherein the inorganic particles are selected from one or more of nitrides, oxides or carbides of metals, semimetals, preferably nitrides, oxides or carbides of aluminum, silicon, boron.

[9]According to [6]]～[8]The method of any one of (1), R of the compound of formula (I)₁And R₂At least one of them is selected from branched alkyl with 4-10 carbon atoms.

[10] Further, the present invention also provides a polyimide film comprising or produced from the polyimide resin composition according to any one of the above [1] to [5].

ADVANTAGEOUS EFFECTS OF INVENTION

Through the implementation of the above technical scheme of the invention, the invention can obtain the following technical effects:

1) the polyimide product, especially the polyimide film, provided by the invention has good thermal conductivity, and even under the condition that the inorganic particles or the inorganic filler have higher filling amount, the thermal conductivity can be obviously improved without damaging the insulating property and the mechanical property of the polyimide product.

2) In the polyimide product provided by the invention, the inorganic particles or the inorganic filler can be uniformly dispersed in a polyimide resin system even in a nanometer size range by adopting specific surface treatment on the inorganic particles or the inorganic filler.

3) The surface modification method for inorganic particles or inorganic fillers provided by the invention is easy to implement and basically not limited by the types of polyimide, so that the method has wider applicability.

Detailed Description

The present invention will be described in detail below. The technical features described below are explained based on typical embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

in the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including the end point numerical value A, B.

In the present specification, the meaning of "inorganic particles" is substantially the same as that of "inorganic filler".

In the present specification, "%" denotes mass% unless otherwise specified.

In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

In this specification, "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Reference throughout this specification to "some particular/preferred embodiments," "other particular/preferred embodiments," "embodiments," or the like, means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

In the present invention, for the sake of convenience of description, the term "dibasic acid anhydride compound" is used collectively for the acid monomers forming the polyimide, and it goes without saying that the term in the present invention includes a compound having a structure of a dibasic acid anhydride and a precursor thereof in the form of a polybasic acid.

< first aspect >

In a first aspect of the present invention, the present application provides a polyimide resin composition comprising:

an inorganic particle, wherein the inorganic particle is,

a polyimide resin,

R₁And R₂Are connected through a chemical bond.

Polyimide resin

The technical solution used in the present invention is in principle applicable to polyimide resins that are conventional in the art. In general, a polyimide can be obtained by dehydrating condensation of a dibasic organic acid anhydride compound with a dibasic organic amine compound.

In the present invention, the dibasic organic acid anhydride compound has a structure represented by the following general formula (II):

wherein the group Y represents a substituted or unsubstituted hydrocarbyl group and the hydrocarbon segments of these hydrocarbyl groups may be interrupted by a heteroatom or heteroatom-containing group selected from S, N, O or C ═ O. In a particular embodiment of the invention, these above mentioned hydrocarbyl groups may also be substituted with a halogen, preferably F or Cl.

In some particular embodiments of the invention, the Y group may be selected from substituted or unsubstituted: phenyl, biphenyl, naphthalene and compounds having the structure represented by the following general formula (II-1):

～Ar～Q～Ar～ (II～1)

wherein Ar represents an aromatic hydrocarbon group or a heteroaromatic group; q represents an alkyl group having 1 to 10 carbon atoms, and the hydrocarbon segments of these alkyl groups may be interrupted by or replaced by heteroatoms or heteroatom-containing groups selected from S, N, O or C ═ O; ar or Q may also be substituted with a halogen, preferably, the halogen is F or Cl.

In other specific embodiments of the present invention, the Y group may be selected from the structures represented by the following general formulae (II-2):

～Ar’～ (II～2)

wherein Ar' is selected from a heteroaromatic group wherein the heteroatom or heteroatom containing group is selected from S, N, O or C ═ O; ar' may also be substituted with a halogen, preferably, the halogen is F or Cl.

Further, in a preferred embodiment of the present invention, the dibasic organic acid anhydride compound may be selected from: pyromellitic dianhydride, 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride, 2,3,3 ', 4' -biphenyltetracarboxylic dianhydride, 3,3 ', 4, 4' -benzophenone tetracarboxylic dianhydride, 2,3,6, 7-naphthalene tetracarboxylic dianhydride, 2, 2-bis (3, 4-dicarboxyphenyl) ether dianhydride, pyridine-2, 3,5, 6-tetracarboxylic dianhydride, or tetracarboxylic acid compounds of the foregoing acid anhydrides.

The organic diamine compound in the present invention may be selected from compounds having the following general formula (III),

H₂N-Z-NH₂

(III)

wherein Z is selected from substituted or unsubstituted hydrocarbyl groups and the hydrocarbon segments of these hydrocarbyl groups may be interrupted by a heteroatom or heteroatom-containing group selected from S, N, O or C ═ O. In a particular embodiment of the invention, these above mentioned hydrocarbyl groups may also be substituted with a halogen, preferably F or Cl.

In some specific embodiments of the invention, Z contains an aromatic hydrocarbon group and/or a heteroaromatic group, wherein the heteroatom or heteroatom-containing group in the heteroaromatic group may be selected from S, N, O or C ═ O.

Further, in a preferred embodiment of the present invention, the organic diamine compound may be selected from the group consisting of p-phenylenediamine, m-phenylenediamine, benzidine, p-xylylenediamine, 4 ' -diaminodiphenyl ether, 3,4 ' -diaminodiphenyl ether, 4 ' -diaminodiphenyl methane, 4 ' -diaminodiphenyl sulfone, 3 ' -dimethyl-4, 4 ' -diaminodiphenyl methane, 1,5 ' -diaminonaphthalene, 3 ' -dimethoxybenzidine, 1,4 ' -bis (3-methyl-5-aminophenyl) benzene.

The polyimide suitable for use in the present invention can be obtained by a condensation reaction of the above-mentioned organic diamine compound and organic acid anhydride compound at a molar ratio of 1:1 to 1.1: 1.

Inorganic particles

In the present invention, the thermal conductivity of a polyimide article, particularly a polyimide film, is improved by dispersing inorganic particles in the polyimide article.

In the present invention, the inorganic particles may be selected from one or more of nitrides, oxides and carbides of metals, semimetals, and preferably nitrides, oxides and carbides of aluminum, silicon and boron. Mention may be made of: oxides, silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, iron oxide, cobalt oxide, copper oxide, or zinc oxide; a nitride selected from silicon nitride, aluminum nitride or boron nitride; a carbide selected from silicon carbide, titanium carbide or boron carbide.

The average particle diameter of the inorganic particles is 10 to 150nm, preferably 10 to 100 nm.

In some preferred embodiments of the present invention, the inorganic particles may be selected from one or more of alumina, silica, aluminum nitride, silicon nitride, and boron nitride.

In the present invention, in order to improve the thermal conductivity of a polyimide article while avoiding a loss of insulation properties and mechanical properties of the article, the inorganic particles are surface-treated with a compound of the general formula (I):

wherein R is₁And R₂The alkyl, cycloalkyl and aromatic groups can be substituted or contain heteroatoms, the heteroatoms are selected from N, S, O or halogen atoms, or,

R₁and R₂Are connected through a chemical bond.

In some preferred embodiments of the present invention, in the compound represented by the general formula (I), R₁Or R₂The alkyl group may be independently selected from a linear or branched alkyl group having 4 to 10 carbon atoms and a cycloalkyl group having 5 to 10 carbon atoms, and more preferably a methyl group, an ethyl group, an isopropyl group, a tert-butyl group or a cyclohexyl group. Typically, the compound of formula (I) according to the present invention may be selected from one or more of tert-butyl methyl dicarbonate, di-tert-butyl dicarbonate, and tert-butyl isopropyl dicarbonate.

In the present invention, the surface treatment of the inorganic particles with the compound represented by the above general formula (I) can significantly improve the compatibility of the inorganic particles with the polyimide resin matrix, and therefore, even when the polyimide is highly filled with the inorganic particles (for example, the content of the inorganic particles is 1 to 25% based on the weight of the polyimide resin in the polyimide resin composition), the mechanical properties and the insulation properties of the polyimide product, particularly the polyimide film, can be not adversely affected.

Wherein, when the inorganic particles are surface-treated with the compound represented by the general formula (I), the molar ratio of the compound represented by the general formula (I) to the inorganic particles may be 1 to 1.2: 1.

In the present invention, the surface treatment method of the inorganic particles with the compound of the general formula (I) is not particularly limited. In some preferred embodiments of the present invention, the inorganic particles may be dried and then reacted with the compound of formula (I) under the action of the catalyst.

The above catalyst, a basic catalyst can be used in the present invention, and in some preferred embodiments, the catalyst can be selected from aminopyridine-based catalysts, preferably, at least one selected from 4-dimethylaminopyridine, 3-dimethylaminopyridine, and 4-methylethylaminopyridine.

The dispersibility of the inorganic nanoparticles can be obviously improved through the drying treatment and the surface modification in the presence of the catalyst, and the compatibility of the inorganic nanoparticles and the polyimide resin is further improved. Therefore, even if inorganic particles having an average particle diameter of the order of nanometers are used, the phenomenon of non-uniform dispersion of the inorganic nanoparticles and the phenomenon of undesirable cracks in the polyimide product, particularly in the polyimide film, in a highly filled state of the inorganic nanoparticles can be better avoided, thereby providing thermal conductivity while still maintaining good insulation properties and mechanical properties.

In the polyimide resin composition of the present invention, the amount of the inorganic particles is 1 to 25% by mass, preferably 2 to 20% by mass, and more preferably 5 to 15% by mass or 5 to 10% by mass, based on the mass of the polyimide in the polyimide resin composition. When the addition amount is less than 1%, the improvement of the thermal conductivity of the inorganic particles to the polyimide resin is not significant; when the amount is more than 25%, the dispersibility of the inorganic particles in the polyimide resin tends to be poor.

< other ingredients >

The polyimide resin composition of the present invention may contain, in addition to the polyimide resin and the inorganic particles, other resin components, functional aids, and the like that are applicable to polyimide resin compositions in the art, without limitation.

For other resin components, without limitation, resin components having some compatibility with polyimide may be used, including but not limited to the following polymers: polyphenylene sulfone, polyetherimide, polysulfone, polycarbonate, polyphenylene oxide, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer, polystyrene, polyvinyl chloride, perfluoroalkoxyalkane polymer, copolymer of tetrafluoroethylene and perfluorovinyl ether, fluorinated ethylene propylene polymer, polyphenylene sulfide, poly (ether ketone), poly (ether-ether ketone), ethylene chlorotrifluoroethylene polymer, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene terephthalate, polyacetal, polyamide, ultra-high molecular weight polyethylene, polypropylene, polyethylene, high density polyethylene, low density polyethylene, polybenzimidazole, poly (amide-imide), poly (ether sulfone), poly (aryl sulfone), polyphenylene, polybenzimidazole, polybenzthiazole, and blends and copolymers thereof.

When the other resin component is contained in the polyimide resin composition, the content of the other resin component is 0% or more and less than 50%, preferably 0 to 30%, more preferably 0 to 10%, based on the total weight of the polyimide resin composition.

The functional aid may be selected from weather resistance agents, antioxidants, ultraviolet absorbers, antistatic agents, plasticizers, lubricants, and the like. The amount used can, of course, follow the usual ranges in the prior art.

In general, in addition to the types of inorganic fillers disclosed above in the present invention, carbon-based particles such as graphite, graphene, carbon nanotubes, and the like may be used as needed without affecting the effect of the present invention. However, in a preferred embodiment of the present invention, these carbon-based particles are not used in view of insulation properties.

< second aspect >

In a second aspect of the present invention, there is provided a method for preparing a polyimide resin composition, comprising:

a step of preparing a polyamic acid solution;

R₁and R₂Are connected through a chemical bond.

The terms "polyimide resin", "inorganic particles" and their related terms referred to in the second aspect of the present invention have the same meanings as those disclosed in the above first aspect of the present invention, unless otherwise specified.

For the step of surface-treating the inorganic particles with the compound of the general formula (I)

In principle, the inorganic particles are not limited as long as the compounds represented by the general formula (I) can be attached to at least part of the surface of the inorganic particles.

In general, the compound of formula (I) can be used as a blend with inorganic particles or as a result of impregnating inorganic particles in a solution or emulsion containing the compound of formula (I) and then drying.

In a preferred embodiment of the invention, the following procedure can be used:

i. and drying the inorganic particles.

Mixing and reacting the dried inorganic particles with a compound of the general formula (I) under the action of a catalyst, wherein the catalyst is the same as the catalyst in the first aspect of the invention. The mixing method is preferably a mixer, a ball mill, or the like.

In addition, as an auxiliary measure, a measure such as stirring, heating, inert gas shielding, or the like may be used in step i or step ii.

In some preferred embodiments of the present invention, step i, typically, may be carried out under an inert gas such as N₂Under protection, drying the inorganic particles at 110-130 ℃ and under the environment with the humidity of 1-20%, wherein the preferable treatment time is at least 10 hours, so as to remove free moisture;

in some preferred embodiments of the present invention, step ii may typically be carried out under an inert gas such as N₂And in the presence of a protection and a catalyst, performing surface treatment on the dried inorganic particles by using a compound of a general formula (I) such as a tert-butyl dicarbonate compound at 60-80 ℃. The treatment time may be 8 to 15 hours, preferably 10 to 12 hours. And then ball milling treatment is carried out, preferably, the ball milling treatment is carried out in the presence of a dispersing agent, and substances such as tetrahydrofuran, n-hexane, benzene, trichloromethane and the like can be used for the dispersing agent. In some embodiments of the present invention, the average particle size of the inorganic particles before the ball milling treatment is 20 to 150nm, and the average particle size of the inorganic particles after the ball milling is reduced to 10 to 150nm, preferably 10 to 100 nm.

In the surface treatment process, the surface of the inorganic particle can be grafted with the compound of the general formula (I) under the action of the catalyst to complete the surface treatment of the inorganic particle as follows:

wherein M represents an inorganic filler or an inorganic particle.

For the step of preparing the polyamic acid solution

In principle, there is no limitation as long as the polyamic acid solution is obtained by condensation reaction of the dibasic organic acid anhydride compound and the dibasic organic amine compound disclosed in the first aspect of the present invention in a polar solvent.

As the polar solvent, those having stronger polarity can be used from the viewpoint of solubility to the reaction monomers and the reaction products, and typically N-methylpyrrolidone (NMP), N-Dimethylformamide (DMF), dimethylacetamide (DMAc) and the like can be used. Further, depending on the monomer or polymer to be used as a solvent, a solvent such as toluene or dimethylsulfoxide may be used in combination.

The reaction ratio of the organic diamine compound to the organic acid anhydride compound may be 1:1 to 1.1:1 in terms of a molar ratio, and the reaction temperature and time may be determined by referring to the operation method for preparing polyamic acid that is generally used in the art.

In some embodiments of the present invention, the polyamic acid solution obtained by the condensation reaction has a solid content of 15 to 25%, and preferably, the polyamic acid solution has a viscosity at 25 ℃ of 50000Cps or more, and more preferably 200000Cps or more.

For the step of dispersing the surface-treated inorganic particles in the polyamic acid solution

After the surface-treated inorganic particles and the polyamic acid solution are obtained as described above, the inorganic particles are mixed with the polyamic acid solution. The mixing method is not limited, and a mixing method generally used in the art may be used. In some embodiments of the present invention, the surface-treated inorganic particles can be uniformly dispersed in the polyamic acid solution by stirring or the like.

In some embodiments of the invention, the dispersion may be carried out in the presence of a dispersant which may be selected from one or a mixture of Gamma Butyrolactone (GBL) or Propylene Glycol Monomethyl Ether Acetate (PGMEA).

The amount of the surface-treated inorganic particles may be 1 to 25% by weight, preferably 2 to 20% by weight, and more preferably 5 to 15% by weight or 5 to 10% by weight, based on the total weight of the dibasic organic acid anhydride compound and the dibasic organic amine compound.

For the step of imidizing the polyamic acid solution in which the inorganic particles are dispersed

The polyamic acid solution in which the inorganic particles are dispersed is placed in an optional mold, or the solution is subjected to film coating on an optional support.

Then, the polyimide film or the molded article can be obtained by heating to raise the temperature to remove the solvent, thermal imidization, and mold release/peeling. In some specific embodiments of the present invention, the heating and temperature-raising step may be: drying at 60-85 ℃ for 1-2 hours to remove the solvent, raising the temperature to 230-260 ℃ at a speed of 1-2 ℃/minute, and then preserving the heat for 1-3 hours. The thermal imidization comprises the following steps: after the solvent is basically removed, the temperature is raised to 340-360 ℃ at the speed of 3-4 ℃/min, and the temperature is kept for 1-2 hours.

The foregoing provides a typical method for preparing a polyimide composition in the second aspect of the present invention. However, other methods may be selected depending on the actual conditions in the preparation of the polyimide composition of the present invention, for example, depending on the processability of polyimide, a solution or a resin of polyimide may be obtained according to a method for preparing polyimide which is generally used in the art, and then the solution or the resin may be solution-mixed or melt-mixed with the surface-treated inorganic particles to obtain the polyimide composition of the present invention.

In addition, the equipment used in the preparation method according to the above second aspect of the present invention is not limited, and the processing equipment generally used in the art may be arbitrarily selected according to actual needs.

< third aspect >

In a third aspect of the invention, the invention provides a polyimide article, particularly a polyimide film article prepared by casting.

For the polyimide articles, they can be obtained by mixing polyamic acid with inorganic particles and then placing them in a mold or coating film, followed by desolvation and imidization according to the second aspect of the present invention. Without limitation, these articles may be any desired molded articles, and typically, may be a plate or a film.

As described above, after the polyimide is obtained, the polyimide and the inorganic particles may be mixed in a solution or melt by heating with a solvent to obtain a composition, and the composition may be optionally molded to obtain a desired product.

For example, these compositions may be formed into articles by any method. Preferred methods include, for example, injection molding, blow molding, compression molding, profile extrusion, sheet or film extrusion, sintering, gas assist molding, structural foam molding, and thermoforming. Examples of such articles include, but are not limited to, membranes, tubes, composites, semiconductor processing tools, wire coatings and jacketing, fluid handling components, cookware, food service items, medical devices, panels, handles, helmets, animal cages, electrical connectors, electrical equipment housings, engine parts, automotive engine parts, bearings, lighting sockets and reflectors, electrical components, power distribution equipment, communication equipment, computers and the like.

Alternatively, the composition resulting from solution or melt mixing may be converted into articles using conventional thermoplastic methods such as film and sheet extrusion. Film and sheet extrusion processes may include, but are not limited to, melt casting, blown film extrusion, and calendering. In some cases, the film can have a thickness of 0.1 to 1000 microns, preferably 0.5 to 800 microns. Coextrusion and lamination processes can be used to form composite multilayer films or sheets. Single or multiple layers of coatings may also be applied to the single or multiple layers of substrates to impart additional properties such as scratch resistance, ultraviolet light resistance, aesthetic appeal, and the like. The coating may be applied by standard application methods such as rolling, spraying, dripping, brushing or flow coating. Alternatively, films and sheets can be prepared by casting a solution or suspension of the above composition in a suitable solvent onto a substrate, belt or roll, followed by removal of the solvent. The film may also be metallized using standard methods such as sputtering, vacuum deposition, and lamination with foil.

Further, an oriented film may also be produced by blown film extrusion, or by stretching a cast or calendered film around the heat distortion temperature using a conventional stretching method. For example, a radial stretch pantograph may be employed for multi-axis simultaneous stretching; the x-y direction stretch pantograph may be used to stretch simultaneously or sequentially in the x-y direction of the plane. It is also possible to use equipment with successive co-axial stretching sections to achieve uniaxial and biaxial stretching, such as a machine equipped with differential speed roller sections for stretching in the machine direction and tenter sections for transverse stretching.

The polyimide molded product obtained according to the present invention, particularly a polyimide film, has excellent thermal conductivity and can avoid deterioration of the insulating property and mechanical properties of the film.

In some preferred embodiments of the present invention, the polyimide film obtained by the present invention has a tensile strength of 280MPa or more, and at the same time, the polyimide film obtained by the present invention has excellent electrical insulation, a breakdown strength of 220kv/mm or more, and a thermal conductivity of 0.36W/m.k or more.

Examples

Hereinafter, specific embodiments of the present invention will be described:

example 1

In N₂Under protection, 200g of inorganic nano-particle boron nitride (120nm) was dehydrated at 120 ℃ overnight under an environment of 20% humidity.

In N₂Under protection, 20g of catalyst 4-dimethylaminopyridine is added into solvent tetrahydrofuran, after uniform dispersion, the inorganic nano-particle boron nitride subjected to water removal treatment and 1758.66g of tert-butyl methyl dicarbonate are added, and reaction is carried out at 70 ℃ for more than 10 hours. Then ball milling is carried out in a ball mill by taking tetrahydrofuran as a dispersion medium to obtain boron nitride nano particles (100 nm); 148.34g of the surface-treated boron nitride nanoparticles obtained above were dispersed in GBL (. gamma. -butyrolactone) to obtain an inorganic nanoparticle dispersion liquid.

882.66g (3mol) of dibasic anhydride 3,3 ', 4,4 ' -biphenyl tetracarboxylic dianhydride and 600.72g (3mol) of diamine 4,4 ' -diaminodiphenyl ether are reacted in a proper amount of polar organic solvent N, N-Dimethylformamide (DMF) to prepare a polyamic acid solution with the solid content of 20 percent and the viscosity of 50000Cps (25 ℃); the obtained inorganic nanoparticle dispersion was added to a polyamic acid solution, and imidization (removal of the solvent by baking at 80 ℃ for 2 hours, heating at a rate of 2 ℃/minute to 240 ℃ and then heat-preservation for 2 hours, substantial removal of the solvent, heating at a rate of 3 ℃/minute to 340 ℃ and heat-preservation for 2 hours) was performed to obtain a polyimide film.

Examples 2 to 9 and comparative examples 1 to 2

The same procedure as in example 1 was carried out under the conditions shown in Table 1.

TABLE 1

The following tests were carried out on the polyimide films of the above examples and comparative examples, and the test results are shown in table 2.

The test items and conditions were as follows:

< mechanical Property test >

The composite films of the present invention were each produced into a film material having a length and width of 25.4mm × 3.2mm, and the tensile strength (MPa) of the film material was measured using a universal tester (manufactured by SHIMADZU scientific instruments ltd., inc. (SHIMADZU), equipment name AG-1S).

< breakdown Strength test >

The breakdown strength is tested by a ZJC-50KV voltage breakdown tester in the middle aviation age, the boosting rate is 0.5kV/s, and the medium is air.

< thermal conductivity test >

Testing according to a hot wire method for measuring the heat conductivity coefficient of GB/T22588-2008;

TABLE 2

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements and the like within the spirit and scope of the present invention should be included.

Industrial applicability

The polyimide resin composition, the preparation method thereof and the film provided by the invention can be industrially produced and applied.

Claims

1. A polyimide resin composition, comprising:

an inorganic particle, wherein the inorganic particle is,

a polyimide resin,

（I）

wherein R is₁And R₂The same or different, each independently selected from a linear or branched alkyl group having 1 to 20 carbon atoms, a C5Cycloalkyl of 20 to 20, and an aromatic group having 6 to 30 carbon atoms, wherein the alkyl, cycloalkyl and aromatic group may be substituted or contain a hetero atom, or

R₁And R₂Are connected through a chemical bond.

2. The polyimide resin composition according to claim 1, wherein the inorganic particles have an average particle diameter of 10 to 150 nm; the amount of the inorganic particles is 1-25% of the mass of the polyimide resin in the composition.

3. The polyimide resin composition according to claim 2, wherein the inorganic particles have an average particle diameter of 10 to 100 nm.

4. The polyimide resin composition according to claim 1 or 2, wherein the inorganic particles are selected from one or more of a nitride, an oxide or a carbide of a metal, a semi-metal.

5. The polyimide resin composition according to claim 4, wherein the inorganic particles are nitrides, oxides or carbides of aluminum, silicon, boron.

6. The polyimide resin composition according to claim 1 or 2, wherein R of the compound of the general formula (I)₁And R₂At least one of them is selected from branched alkyl with 4-10 carbon atoms.

7. The polyimide resin composition according to claim 1 or 2, wherein the polyimide resin is prepared from a dibasic organic acid anhydride compound and a dibasic organic amine compound, and the molar ratio of the dibasic organic amine compound to the dibasic organic acid anhydride compound is 1:1 to 1.1: 1.

8. A method for producing a polyimide resin composition, comprising:

a step of preparing a polyamic acid solution;

（I）

R₁And R₂Are connected through a chemical bond.

9. The method according to claim 8, wherein the inorganic particles have an average particle diameter of 10 to 150 nm; the amount of the inorganic particles is 1-25% of the mass of the polyimide resin in the composition.

10. The method according to claim 9, wherein the inorganic particles have an average particle diameter of 10 to 100 nm.

11. The method according to claim 8 or 9, wherein the inorganic particles are selected from one or more of a metal, a nitride, an oxide or a carbide of a semi-metal.

12. The method of claim 11, wherein the inorganic particles are nitrides, oxides, or carbides of aluminum, silicon, boron.

13. The method according to claim 8 or 9, wherein R of the compound of formula (I)₁And R₂At least one of them is selected from branched alkyl with 4-10 carbon atoms.

14. A polyimide film comprising or produced from the polyimide resin composition according to any one of claims 1 to 7.