阅读说明：本技术 聚合物基介电材料及其制备方法 (Polymer-based dielectric material and preparation method thereof ) 是由 李峰 刘侠侠 陶玉红 李露 卢星华 袁启斌 于 2019-10-10 设计创作，主要内容包括：本发明提供一种聚合物基介电材料的制备方法以及由该制备方法制得的聚合物基介电材料。在本发明中,通过将环氧树脂预聚物、丁腈橡胶、非极性单体、自由基引发剂和溶剂混合,并与高介电常数无机填料混合均匀,烘干、在100～200℃进行固化,使得混合物中的树脂预聚物、丁腈橡胶、非极性单体在自由基引发剂发生聚合反应,由此形成所需的聚合物基介电材料。所得到的聚合物基介电材料具有超低介电损耗、高介电常数。(The invention provides a preparation method of a polymer-based dielectric material and the polymer-based dielectric material prepared by the preparation method. According to the invention, epoxy resin prepolymer, nitrile rubber, nonpolar monomer, free radical initiator and solvent are mixed, and are uniformly mixed with high dielectric constant inorganic filler, dried and cured at 100-200 ℃, so that the resin prepolymer, nitrile rubber and nonpolar monomer in the mixture are subjected to polymerization reaction in the free radical initiator, and the required polymer-based dielectric material is formed. The obtained polymer-based dielectric material has ultralow dielectric loss and high dielectric constant.)

1. A method of making a polymer-based dielectric material, comprising the steps of: mixing and dissolving an epoxy resin prepolymer, nitrile rubber, a non-polar monomer, a free radical initiator and a solvent into a uniform mixed solution; uniformly mixing the mixed solution with the high-dielectric-constant inorganic filler by using a high-speed dispersion machine to form uniform dispersion liquid; and coating the dispersion on a base material, drying the solvent, and then placing the base material in an oven to be cured at 100-200 ℃ to form the required polymer-based dielectric material.

2. The method of claim 1, the polymer-based dielectric material having a dielectric constant D_kBetween 13 and 30, and dielectric loss Df is less than or equal to 0.5 percent.

3. The method according to claim 1, wherein the mass percentages of the components in the mixed solution are 20-40 wt% of the epoxy resin prepolymer, 5-10 wt% of the nitrile rubber, 30-50 wt% of the non-polar monomer, 0.5-1 wt% of the radical initiator and 10-20 wt% of the solvent, based on the total mass of the mixed solution, and the sum of the mass percentages of the components is 100%.

4. The production method according to claim 1, wherein the dispersion liquid comprises 20 to 60 wt% of the mixed solution and 40 to 80 wt% of the inorganic filler, based on the total mass of the dispersion liquid, and the sum of the mass percentages of the components is 100%.

5. The process according to claim 1, wherein the epoxy resin prepolymer is an acrylic and/or methacrylic-terminated aromatic or aliphatic epoxy resin having two or more functional groups;

preferably, the epoxy prepolymer is selected from one or more of the following combinations: novolac epoxy resin, bisphenol a epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, tetrabromobisphenol a epoxy resin, diglycidyl phthalate, dicyclopentadiene diepoxide, bis (3, 4-epoxy-6-methylcyclohexyl) adipate, 3, 4-epoxy-6-methylcyclohexanoic acid-3 ', 4' epoxy-6-methylcyclohexylmethyl ester, bis (2, 3-epoxy cyclopentyl) ether, vinylcyclohexene diepoxide.

6. The process according to claim 1, wherein the nitrile rubber has functional groups reactive with epoxy groups at the terminal or pendant groups, selected from one or more of the following: carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber and liquid random carboxyl nitrile rubber.

7. The method of claim 1, wherein the non-polar monomer is selected from one or more of the following monomers: styrene, isobornyl acrylate, vinyl pyrrolidone, tetrahydrofurfuryl acrylate, lauric acrylate, dodecyl acrylate, stearic acid methacrylate, tris (2-hydroxyethyl) isocyanate triacrylate; and/or

The free radical initiator is selected from one or more of the following: cumene hydroperoxide, tert-butyl hydroperoxide, p-menthane hydroperoxide, dibenzoyl peroxide, lauroyl peroxide, ditert-butyl peroxide, dicumyl peroxide, diisopropyl peroxydicarbonate; and/or

The solvent is selected from one or more of the following substances: ethyl acetate, butyl acetate, propyl acetate, butanone, acetone, pentanone, toluene, xylene, dichloroethane, absolute ethanol, butanol, and propanol.

8. A polymer-based dielectric material prepared according to the preparation method of any one of claims 1 to 7, wherein the polymer-based dielectric material is composed of an organic polymer matrix and a high dielectric constant inorganic filler uniformly dispersed therein, and the organic polymer matrix is a cross-linked network structure formed by cross-linking polymerization of an epoxy resin prepolymer, nitrile rubber and a non-polar monomer under the action of a free radical initiator.

Technical Field

The invention belongs to the technical field of flexible thin film capacitors, and particularly relates to a preparation method of a polymer-based dielectric material with ultralow dielectric loss and high dielectric constant, and the polymer-based dielectric material prepared by the preparation method.

Background

The high-dielectric-constant dielectric material formed by compounding the high-molecular polymer matrix and the high-dielectric-constant inorganic filler can be used as a capacitor-embedded material, and is embedded in a PCB substrate to replace a separate capacitor component during PCB manufacturing, so that the PCB layout area is greatly saved. However, the dielectric loss of the existing capacitor-embedded material is between 2 and 3 percent, which is too high for 5G technology, and the requirement of high-speed transmission of 5G signals cannot be met.

Generally, a dielectric material compounded from a polymer matrix and a high dielectric constant inorganic filler has a dielectric loss close to that of the polymer matrix. Therefore, if the dielectric loss of the polymer matrix can be reduced, it would be advantageous to prepare a high dielectric constant polymer capacitor material with low dielectric loss.

Disclosure of Invention

In order to solve the problems, the invention provides a polymer-based dielectric material with ultralow dielectric loss and high dielectric constant and a preparation method thereof.

In one aspect, the present invention provides a method for preparing a polymer-based dielectric material, comprising the steps of: mixing and dissolving an epoxy resin prepolymer, nitrile rubber, a non-polar monomer, a free radical initiator and a solvent into a uniform mixed solution; uniformly mixing the mixed solution with the high-dielectric-constant inorganic filler by using a high-speed dispersion machine to form uniform dispersion liquid; and coating the dispersion on a base material, drying the solvent, and then placing the base material in an oven to be cured at 100-200 ℃ to form the required polymer-based dielectric material.

According to one embodiment of the present invention, the polymer-based dielectric material has a dielectric constant D_kBetween 13 and 30, a dielectric loss D_f≤0.5％。

According to one embodiment of the invention, the mass percentages of the components in the mixed solution are 20-40 wt% of epoxy resin prepolymer, 5-10 wt% of nitrile rubber, 30-50 wt% of non-polar monomer, 0.5-1 wt% of radical initiator and 10-20 wt% of solvent based on the total mass of the formed mixed solution.

According to an embodiment of the present invention, the dispersion liquid is formed by mixing 20 to 60 wt% of the mixed solution and 40 to 80 wt% of the inorganic filler in mass percentage based on the total mass of the dispersion liquid.

According to one embodiment of the present invention, the epoxy resin prepolymer is an acrylic and/or methacrylic terminated aromatic or aliphatic epoxy resin containing two or more functional groups; preferably, the epoxy prepolymer is selected from one or more of the following combinations: novolac epoxy resin, bisphenol a epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, tetrabromobisphenol a epoxy resin, diglycidyl phthalate, dicyclopentadiene diepoxide, bis (3, 4-epoxy-6-methylcyclohexyl) adipate, 3, 4-epoxy-6-methylcyclohexanoic acid-3 ', 4' epoxy-6-methylcyclohexylmethyl ester, bis (2, 3-epoxy cyclopentyl) ether, vinylcyclohexene diepoxide.

According to one embodiment of the invention, the nitrile rubber bears functional groups on terminal or pendant groups which are reactive with epoxy groups, selected from one or more of the following: carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber and liquid random carboxyl nitrile rubber.

According to one embodiment of the invention, the non-polar monomer is selected from one or more of the following monomers: styrene, isobornyl acrylate, vinyl pyrrolidone, tetrahydrofurfuryl acrylate, lauric acrylate, dodecyl acrylate, stearic acid methacrylate and tris (2-hydroxyethyl) isocyanate triacrylate.

According to one embodiment of the invention, the radical initiator is selected from one or more of the following: cumene hydroperoxide, tert-butyl hydroperoxide, p-menthane hydroperoxide, dibenzoyl peroxide, lauroyl peroxide, ditert-butyl peroxide, dicumyl peroxide, and diisopropyl peroxydicarbonate.

According to one embodiment of the invention, the solvent is selected from one or several of the following: ethyl acetate, butyl acetate, propyl acetate, butanone, acetone, pentanone, toluene, xylene, dichloroethane, absolute ethanol, butanol, and propanol.

According to one embodiment of the invention, the curing step is carried out in an oven at 100-200 ℃.

On the other hand, the invention also provides the polymer-based dielectric material prepared by the preparation method, which consists of an organic polymer matrix and the high-dielectric-constant inorganic filler uniformly dispersed in the organic polymer matrix, wherein the organic polymer matrix is a cross-linked network structure formed by the cross-linking polymerization reaction of an epoxy resin prepolymer, nitrile rubber and a nonpolar monomer under the action of a free radical initiator.

In the application, the use of a dispersing agent is omitted, and because the epoxy resin prepolymer and the nitrile rubber form a mixed solution with a certain consistency after being dissolved, the inorganic filler is uniformly dispersed in the dispersion liquid after being stirred by the shear stress of a high-speed dispersing machine, and cannot be immediately re-precipitated and then aggregated. Therefore, the dispersant is omitted, the aim of uniform dispersion can be achieved, and the influence of the dispersant on the material performance is reduced.

Secondly, under the action of a free radical initiator, double bonds contained in the nitrile rubber and double bonds contained in the nonpolar monomer are subjected to polymerization reaction; secondly, under the condition that the terminal group or the side group of the nitrile rubber has a functional group capable of reacting with an epoxy group, the carboxyl of the nitrile rubber can perform a ring-opening reaction with the epoxy group of the epoxy resin, and the carboxyl of the nitrile rubber can also perform an esterification reaction with the hydroxyl on the side chain of the epoxy resin; third, in radical polymerization, for example, methylene groups on bisphenol a epoxy resin molecules are easily formed into radicals and copolymerized with vinyl monomers by the action of a peroxide initiator, and polymer chains of nonpolar monomers are introduced into molecular chains of the epoxy resin. Therefore, not only the molecular chain of the nitrile rubber but also the polymer chain of the non-polar monomer is introduced on the molecular chain of the epoxy resin to form a cross-linked network structure.

The polymer matrix formed by the method introduces nonpolar low-loss groups and polymers, and can reduce the dielectric loss of the formed polymer-based dielectric material. In the curing process, the inorganic filler is uniformly cured in the cross-linked network structure, so that the inorganic filler particles are prevented from contacting with each other due to non-uniform dispersion of the inorganic filler, thereby reducing leakage current and dielectric loss.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understandable, the following specific preferred embodiments are described in detail.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the present invention will be described in detail with reference to the following embodiments. It is to be understood that the following examples are illustrative of the invention only and are not limiting thereof.

The application provides a preparation method of a polymer-based dielectric material with ultralow dielectric loss and high dielectric constant, which comprises the following steps: mixing and dissolving an epoxy resin prepolymer, nitrile rubber, a non-polar monomer, a free radical initiator and a solvent into a uniform mixed solution; uniformly mixing the mixed solution and the high-dielectric-constant inorganic filler by using a high-speed dispersion machine to form uniform dispersion liquid; and coating the dispersion on a base material, drying the solvent, and then placing the base material in an oven to be cured at 100-200 ℃ to form the required polymer-based dielectric material. In the present application, the dielectric constant (D) of the polymer-based dielectric material_k) Higher, between 13 and 30; dielectric loss (D)_f) Lower, D_f≤0.5％。

In one embodiment, the mass percentages of the components in the mixed solution are 20-40 wt% of epoxy resin prepolymer, 5-10 wt% of nitrile rubber, 30-50 wt% of non-polar monomer, 0.5-1 wt% of radical initiator and 10-20 wt% of solvent, and the sum of the mass percentages of the components is 100%, based on the total mass of the formed mixed solution.

In one embodiment, the dispersion liquid contains 20 to 60 wt% of each component and 40 to 80 wt% of the inorganic filler, based on the total mass of the dispersion liquid, and the sum of the mass percentages of the components is 100%.

In one embodiment of the present application, the epoxy resin prepolymer is an acrylic and/or methacrylic terminated aromatic or aliphatic epoxy resin containing two or more functional groups. In one embodiment, the epoxy prepolymer is selected from one or more of the following combinations: novolac epoxy resin, bisphenol a epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, tetrabromobisphenol a epoxy resin, diglycidyl phthalate, dicyclopentadiene diepoxide, bis (3, 4-epoxy-6-methylcyclohexyl) adipate, 3, 4-epoxy-6-methylcyclohexanoic acid-3 ', 4' epoxy-6-methylcyclohexylmethyl ester, bis (2, 3-epoxy cyclopentyl) ether, vinylcyclohexene diepoxide.

In one embodiment, the nitrile rubber bears functional groups on terminal or pendant groups that are reactive with epoxy groups, selected from one or more of the following: carboxyl-terminated nitrile rubber, hydroxyl-terminated nitrile rubber and liquid random carboxyl nitrile rubber. Thus, during curing, the nitrile rubber can react with the epoxy resin, introducing a nitrile rubber polymer into the matrix of the epoxy resin.

The nonpolar monomer is one or more monomers capable of free radical polymerization. In one embodiment, the non-polar monomer is selected from one or more of the following monomers: styrene, isobornyl acrylate, vinyl pyrrolidone, tetrahydrofurfuryl acrylate, lauric acrylate, dodecyl acrylate, stearic acid methacrylate and tris (2-hydroxyethyl) isocyanate triacrylate.

In one embodiment of the present application, the curing step is performed at 100 to 200 ℃, for example, at 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃. Further, the curing step is carried out in an oven.

The free radical initiator is a free radical polymerization initiator which can decompose free radicals at 100-200 ℃ and initiate the polymerization of monomers containing double bonds. In one embodiment, the free radical initiator is selected from one or more of the following: cumene hydroperoxide, tert-butyl hydroperoxide, p-menthane hydroperoxide, dibenzoyl peroxide, lauroyl peroxide, ditert-butyl peroxide, dicumyl peroxide, and diisopropyl peroxydicarbonate.

The solvent can dissolve the nitrile rubber and the epoxy resin prepolymer simultaneously, and in one embodiment, the solvent is selected from one or more of the following substances: ethyl acetate, butyl acetate, propyl acetate, butanone, acetone, pentanone, toluene, xylene, dichloroethane, absolute ethanol, butanol, and propanol.

The inorganic filler is ceramic powder, the dielectric constant of the inorganic filler is more than or equal to 1000 under the test frequency of 1kHz, the dielectric loss is less than or equal to 0.05, and the particle size D₅₀50-100 nm. In one embodiment, the inorganic filler is selected from one or more of the following: sodium barium titanate, copper calcium titanate, strontium titanate, barium strontium titanate, calcium titanate, barium calcium titanate, lead zirconate titanate, sodium lead titanate, and lead titanate.

In the present application, the process of forming the dispersion, this step of mixing uniformly includes sanding 4 ~ 5 times with a sand mill, thereby making the dispersion obtained more uniform.

In the present application, firstly, under the action of a free radical initiator, the double bonds contained in the nitrile rubber and the double bonds contained in the nonpolar monomer undergo a polymerization reaction; secondly, under the condition that the terminal group or the side group of the nitrile rubber has a functional group capable of reacting with an epoxy group, the carboxyl of the nitrile rubber can perform a ring-opening reaction with the epoxy group of the epoxy resin, and the carboxyl of the nitrile rubber can also perform an esterification reaction with the hydroxyl on the side chain of the epoxy resin; third, in radical polymerization, for example, methylene groups on bisphenol a epoxy resin molecules are easily formed into radicals and copolymerized with vinyl monomers by the action of a peroxide initiator, and polymer chains of nonpolar monomers are introduced into molecular chains of the epoxy resin. Therefore, not only the molecular chain of the nitrile rubber but also the polymer chain of the non-polar monomer is introduced on the molecular chain of the epoxy resin to form a cross-linked network structure.

The polymer matrix formed by the method introduces nonpolar low-loss groups and polymers, and can reduce the dielectric loss of the formed polymer-based dielectric material. In the curing process, the inorganic filler is uniformly cured in the cross-linked network structure, so that the inorganic filler particles are prevented from contacting with each other due to non-uniform dispersion of the inorganic filler, thereby reducing leakage current and dielectric loss.

The invention also provides the polymer-based dielectric material prepared by the preparation method, the polymer-based dielectric material consists of an organic polymer matrix and high-dielectric-constant inorganic filler uniformly dispersed in the organic polymer matrix, and the organic polymer matrix is a cross-linked network structure formed by cross-linking and polymerizing epoxy resin prepolymer, nitrile rubber and nonpolar monomer under the action of a free radical initiator.

The present invention will be described in further detail with reference to examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below.