Polyimide porous body and method for producing same

Abstract

The purpose of the present invention is to provide: a polyimide porous body with low relative permittivity, excellent heat resistance, and a fine cell structure; and a method for producing the polyimide porous body. The purpose of the present invention is also to provide: a polyimide porous body having extremely fine pore sizes so as to minimize reductions in insulation properties and mechanical strength specific to porous bodies; and a method for producing the polyimide porous body. This method for producing the polyimide porous body includes: a step for applying a polymer solution containing polyamide acid, a phase separation agent for separating the phases of the polyamide acid, an imidization catalyst, and a dehydrating agent, on a substrate, and drying the polymer solution to produce a phase-separated structure having a microphase-separated structure; a step for producing a porous body by removing the phase separation agent from the phase-separated structure; and a step for subjecting the polyamide acid in the porous body to imidization to synthesize a polyimide.

Description

technical field [0001] The present invention relates to a polyimide porous body having fine cells, a low relative permittivity, and excellent heat resistance, and a method for producing the same. The porous polyimide body of the present invention is suitable for use in, for example, circuit boards of electronic equipment and the like. Background technique [0002] Conventionally, plastic films have high insulating properties, so they have been used in components or components that require reliability, such as electronic / electrical equipment such as circuit boards and printed circuit boards, or electronic components. Recently, with the high performance and high functionality of electronic / electrical equipment, in the field of electrical equipment that stores, processes and transmits large amounts of information at high speed, high performance of plastic materials used for them is also required. In particular, lower dielectric constant and lower dielectric loss tangent are re...

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Problems solved by technology

[0009] However, the above-mentioned physical method points out the harmfulness of the substance used as a blowing agent, and the impact on the environment such as the ozone layer depletion caused by the substance, etc.

In addition, although it is a suitable method for obtaining a foam having an average pore diameter of several tens of μm or more, it is difficult to obtain a foam having fine and uniform cells.

[0010] On the other hand, the chemical method has the possibility of residues of the blowing agent remaining in the foam after the gas is generated after foaming, so it is not suitable for applications that strongly require low pollution of electronic / electrical equipment and electronic parts. of

[0011] In addition, in the method described in Patent Document 2, when impregnating a polymer with high-pressure gas, the pressure vessel is heated to the Vicat softening point of the polymer or its vicinity, so that the polymer is in a molten state during decompression and the high-pressure gas It is easy to expand, so the cell size of the obtained foam will not be so small. For example, when the foam is used for a circuit board, etc., its thickness becomes thicker, or there is a limit to the miniaturization in its patterning.

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