A kind of dielectric film and preparation method thereof

Abstract

The invention discloses a dielectric film and a preparation method thereof. Polyester diol with an even number of carbon atoms, 1,4-butanediol and diisocyanate containing at least one symmetrical plane structure are used as raw materials, and the synthetic isocyanate index is 0.95-1.01 polyurethane; dissolve the polyurethane in a solvent containing at least one symmetry plane in the molecular structure conformation, fully stir to form a slurry; add flake metal alloy soft magnetic powder to the slurry, and stir evenly to obtain a mixed slurry; mixed slurry The material is coated on the release substrate to form a film with a thickness of 0.02-0.3 mm, and it is obtained after drying. A kind of thin film material with high dielectric constant, low dielectric loss and high magnetic permeability in alternating electric field is prepared by this method, especially the film material with high permeability controlled by molecular chain structure in the frequency range of 1MHz to 3GHz. The dielectric film material with the real part value of the complex permittivity, the low imaginary part value of the complex permittivity, and the high real part value of the complex permeability.

Description

technical field [0001] The invention relates to the field of electromagnetic materials, in particular to a dielectric thin film with high dielectric constant, low dielectric loss and high magnetic permeability based on molecular chain segment control and a preparation method thereof. Background technique [0002] The dielectric constant of a material reflects the ability of the material to generate induced charges and weaken the electric field when an electric field is applied. In an alternating electric field, the complex permittivity of a material can be expressed as ε r =ε'-jε" where ε' is the real part of the complex permittivity, which reflects the ability to store charges during the polarization of the dielectric, and ε" is the imaginary part of the complex permittivity, which reflects the energy loss during the polarization of the dielectric . Similarly, the complex permeability of a material can be expressed as μ r =μ’-jμ”, where μ’ is the real part of the complex...

AI Technical Summary

Problems solved by technology

The dielectric constant of these films is high, and the dielectric loss is also high at the same time. At the same time, the magnetic energy storage capacity of the magnetic field is poor, especially the addition of fillers such as carbon black, which will seriously affect the storage and utilization of the magnetic field energy when the film is dealing with the electric field energy.

Invention patent CN103193477B discloses a kind of Ca (4-3x) Cu 3x Ti 4 o 12 Composite metal oxides and C n h 2n+1 COOH is a dielectric film made of carboxylic acid with the general formula as an organic solvent. It has a high dielectric constant and can be evenly coated, but it also has the defects of high dielectric loss and poor storage capacity for magnetic fields; invention patent application PCT / EP2013 / 063170 discloses a dielectric polyurethane film with high dielectric constant and resistivity, which is suitable for the manufacture of electromechanical transducers. The high resistivity enables the material to have a low dielectric constant while having a high dielectric constant. Dielectric loss, but also lacks the ability to simultaneously store and utilize magnetic field energy