阅读说明：本技术 一种低介电聚酰亚胺、其制备方法及低介电聚酰亚胺薄膜 (Low-dielectric polyimide, preparation method thereof and low-dielectric polyimide film ) 是由 徐勇 陈坚 汤学妹 于 2020-05-19 设计创作，主要内容包括：本发明提供的一种低介电聚酰亚胺。本发明还提供了上述高性能低介电聚酰亚胺的制备方法。本发明还提供了一种低介电聚酰亚胺薄膜,包括所述低介电聚酰亚胺、含氟硅氧烷、多孔壳聚糖；其中,含氟硅氧烷的质量为低介电聚酰亚胺质量的1-2％,多孔壳聚糖为低介电聚酰亚胺质量的0.5-1％。本发明的聚酰亚胺薄膜,采用特殊的聚酰亚胺大大降低了介电常数,兼具优良的耐热稳定性、高玻璃化转变温度、高透明性以及优异的阻燃性能,同时通过添加含氟硅氧烷、多孔壳聚糖,获得一种具有低介电常数、高耐水性的聚酰亚胺薄膜,并且在改善上述性能的同时不会损伤聚酰亚胺薄膜自身的绝缘性能及各项力学性能。(The invention provides low dielectric polyimide. The invention also provides a preparation method of the high-performance low-dielectric polyimide. The invention also provides a low dielectric polyimide film, which comprises the low dielectric polyimide, fluorine-containing siloxane and porous chitosan; wherein, the mass of the fluorine-containing siloxane is 1 to 2 percent of the mass of the low dielectric polyimide, and the mass of the porous chitosan is 0.5 to 1 percent of the mass of the low dielectric polyimide. The polyimide film disclosed by the invention has the advantages that the dielectric constant is greatly reduced by adopting special polyimide, the polyimide film has excellent heat-resistant stability, high glass transition temperature, high transparency and excellent flame retardant property, meanwhile, the polyimide film with low dielectric constant and high water resistance is obtained by adding the fluorine-containing siloxane and the porous chitosan, and the insulating property and various mechanical properties of the polyimide film can not be damaged while the properties are improved.)

1. a low dielectric polyimide having the formula V:

2. the method for preparing a low dielectric polyimide according to claim 1, wherein: the method comprises the following steps:

(1) reacting the compound shown in the formula VI with the compound shown in the formula VII to obtain an intermediate shown in the formula VIII;

(2) VIII, reacting the intermediate to obtain a compound shown in a formula V;

the reaction formula is as follows:

3. the method for preparing low dielectric polyimide according to claim 2, wherein: the method comprises the following steps:

(1) under the protection of nitrogen and at a certain temperature, stirring the compound shown in the formula VI and the compound shown in the formula VII in an organic solvent for reaction to obtain an intermediate shown in the formula VIII;

(2) adding a dehydrating agent and a catalyst, continuously stirring the intermediate shown as VIII at a certain temperature for reaction, cleaning, filtering and drying to obtain the compound shown as the formula V.

4. The method for preparing low dielectric polyimide according to claim 3, wherein: in the step (1), the organic solvent is one of N-methyl pyrrolidone, N-dimethyl acetamide or N, N-dimethyl formamide; the reaction temperature is 5-25 ℃.

5. The method for preparing low dielectric polyimide according to claim 3, wherein: in the step (2), the dehydrating agent is one or a mixture of more of trifluoroacetic anhydride, acetic anhydride, thionyl chloride or an organic silicon compound; the molar ratio of the dehydrating agent to the compound VII is 3: 1-5: 1; the catalyst is one or a mixture of triethylamine and pyridine, and the molar ratio of the catalyst to the compound VII is 2: 1-4: 1; the reaction temperature is 40-60 ℃.

6. Use of the low dielectric polyimide of claim 1 in high frequency communications.

7. A low dielectric polyimide film characterized in that: comprising the low dielectric polyimide of claim 1, a fluorosilicone, a porous chitosan; wherein, the mass of the fluorine-containing siloxane is 1 to 2 percent of the mass of the low dielectric polyimide, and the mass of the porous chitosan is 0.5 to 1 percent of the mass of the low dielectric polyimide.

8. The low dielectric polyimide film of claim 7, wherein: the fluorine-containing siloxane is one or more of heptafluoropentyl triethoxysilane, heptafluoropentyl trimethoxysilane, heptafluoropentyl trichlorosilane, perfluorooctyl ethyl trimethoxysilane, perfluorooctyl ethyl triethoxysilane, tridecafluorooctyl trimethoxysilane and tridecafluorooctyl trichlorosilane.

9. The method for producing a low dielectric polyimide film as defined in claim 8, wherein: the method comprises the following steps:

(1) adding fluorine-containing siloxane and chitosan into an organic solvent respectively to obtain a fluorine-containing siloxane solution and a chitosan solution;

(2) heating the low dielectric polyimide of claim 1 to 50-60 ℃, stirring at a constant temperature; then dropwise adding the fluorine-containing siloxane solution while stirring; stirring and naturally cooling to 30-40 ℃, and dripping chitosan solution while cooling;

(3) and (3) preparing the product of the step (2) into a film, namely the low dielectric polyimide film.

10. Use of the low dielectric polyimide of claim 7 in high frequency communications.

Technical Field

The invention relates to the field of materials, in particular to low dielectric polyimide.

Background

Polyimide is a polymer having an imide ring (-CO-NH-CO-) in the main chain, and among them, a polymer having a phthalimide structure is most important. Polyimide is one of organic polymer materials with the best comprehensive performance, has the advantages of high temperature resistance, low dielectric constant, corrosion resistance and the like, has the high temperature resistance of over 400 ℃, has the long-term use temperature range of-200-300 ℃, and has very high insulating property. Polyimide is used as a special engineering material, has been widely applied to the fields of aviation, aerospace, microelectronics, nano-materials, liquid crystals, separation membranes, lasers and the like, and becomes an irreplaceable functional material with excellent comprehensive performance.

Polyimide (PI) has excellent heat resistance, good mechanical property, stable chemical property, excellent dielectric property, non-toxicity, irradiation resistance and other properties, and has relatively simple preparation process and excellent comprehensive performance, and is receiving more and more attention.

There are various methods for preparing a low dielectric constant polyimide film, including:

firstly, introducing fluorine-containing groups or substituting fluorine for hydrogen to synthesize low-dielectric-constant polyimide: namely, the fluorine-containing polyimide is obtained by reacting fluorine-containing dianhydride with diamine to generate a prepolymer (polyamide acid or polyamide ester) and then carrying out chemical imidization or heat treatment. Partially fluorinated polyimides are currently the most studied because perfluorinated polyimide monomers are less versatile, more toxic, difficult to synthesize, and more costly.

Secondly, a fluorene group-containing low dielectric constant polyimide: the fluorenyl has huge free volume and a condensed ring structure, so that the polyimide containing the fluorenyl has better solubility, thermal oxidation stability, mechanical property, low dielectric constant, dielectric loss and the like. The method is widely applied to high and new technology industries such as microelectronics, separation membranes, advanced display screens and the like.

Thirdly, polyimide/silicon dioxide composite material: the mixed solution of the SiO2 precursor and water is added to the polyamic acid solution and stirred to obtain a mixed solution of SiO2 and polyamic acid, and a film is formed by an appropriate method. Finally, the polyimide and nano SiO2 composite material is prepared through imidization heat treatment.

Fourthly, nano-porous low dielectric constant polyimide: as mentioned above, the low dielectric constant (close to 1) of air is utilized to introduce nanometer-level holes into the polyimide film material, so that the dielectric constant of the material can be effectively reduced.

Obviously, the fourth method, namely nano-pore, is the simplest and the most applicable method among the four methods for preparing the polyimide film with low dielectric constant. By taking the reference of the preparation methods of nano-pore materials in other fields, the nano-pore structure can be constructed in the polyimide film by means of a secondary deposition method, a sol-gel method, a thermal decomposition method, a supercritical foaming method and the like. However, the pore size distribution of the obtained nanopores is often wide (poor uniformity), so that the application performance of the material is poor. For example, in the field of microelectronics, polyimide films containing a large number of nanoporous structures with non-uniform pore sizes tend to have poor electrical breakdown resistance, which is obviously one of the important properties of dielectric materials. In view of the above, there is a need to provide a new method for constructing a uniform nano-pore structure in a polyimide film, and further for preparing a polyimide film with an ultra-low dielectric constant.

However, the dielectric constant of the current polyimides is still not satisfactory.

Disclosure of Invention

The technical problem is as follows: in order to solve the defects of the prior art, the invention provides low dielectric polyimide and a preparation method and application thereof.

The invention also provides a low dielectric polyimide film.

The technical scheme is as follows: the invention provides low dielectric polyimide, which has a structural formula shown as a formula V:

the invention also provides a preparation method of the high-performance low-dielectric polyimide, which comprises the following steps:

(1) reacting the compound shown in the formula VI with the compound shown in the formula VII to obtain an intermediate shown in the formula VIII;

(2) VIII, reacting the intermediate to obtain a compound shown in a formula V;

the reaction formula is as follows:

preferably, the preparation method of the low dielectric polyimide comprises the following steps:

(1) under the protection of nitrogen and at a certain temperature, stirring the compound shown in the formula VI and the compound shown in the formula VII in an organic solvent for reaction to obtain an intermediate shown in the formula VIII;

(2) adding a dehydrating agent and a catalyst, continuously stirring the intermediate shown as VIII at a certain temperature for reaction, cleaning, filtering and drying to obtain the compound shown as the formula V.

In the step (1), the organic solvent is one of N-methyl pyrrolidone, N-dimethyl acetamide or N, N-dimethyl formamide; the reaction temperature is 5-25 ℃.

In the step (2), the dehydrating agent is one or a mixture of more of trifluoroacetic anhydride, acetic anhydride, thionyl chloride or an organic silicon compound; the molar ratio of the dehydrating agent to the compound VII is 3: 1-5: 1.

In the step (2), the catalyst is one or a mixture of triethylamine and pyridine, and the molar ratio of the catalyst to the compound VII is 2: 1-4: 1.

In the step (2), the reaction temperature is 40-60 ℃.

The invention also provides application of the low-dielectric polyimide in a flexible AMOLED.

The invention also provides a low dielectric polyimide film, which comprises the low dielectric polyimide, fluorine-containing siloxane and porous chitosan; wherein, the mass of the fluorine-containing siloxane is 1 to 2 percent of the mass of the low dielectric polyimide, and the mass of the porous chitosan is 0.5 to 1 percent of the mass of the low dielectric polyimide.

Preferably, the fluorine-containing siloxane is one or more of heptafluoropentyltriethoxysilane, heptafluoropentyltrimethoxysilane, heptafluoropentyltrichlorosilane, perfluorooctylethyltrichlorosilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, tridecafluorooctyltrimethoxysilane.

The invention also provides a preparation method of the low-dielectric polyimide film, which comprises the following steps:

(1) adding fluorine-containing siloxane and chitosan into an organic solvent respectively to obtain a fluorine-containing siloxane solution and a chitosan solution;

(2) heating the low dielectric polyimide to 50-60 ℃, and stirring at constant temperature; then dropwise adding the fluorine-containing siloxane solution while stirring; stirring and naturally cooling to 30-40 ℃, and dripping chitosan solution while cooling;

(3) and (3) preparing the product of the step (2) into a film, namely the low dielectric polyimide film.

The invention also provides the application of the low dielectric polyimide in high-frequency communication.

Has the advantages that: the polyimide film disclosed by the invention has the advantages that the dielectric constant is greatly reduced by adopting special polyimide, the polyimide film has excellent heat-resistant stability, high glass transition temperature, high transparency and excellent flame retardant property, meanwhile, the polyimide film with low dielectric constant and high water resistance is obtained by adding the fluorine-containing siloxane and the porous chitosan, and the insulating property and various mechanical properties of the polyimide film can not be damaged while the properties are improved.

Detailed Description

The present invention is further explained below.

In the following examples, the reaction scheme is as follows: