TW202221080A - Polymer dispersion, method for manufacturing the polymer dispersion, and polymer composite film and its application - Google Patents

Abstract

A polymer dispersion is disclosed. The polymer dispersion includes a liquid crystal polymer powder, a polyamide acid, and a solvent. A solid content of the polymer dispersion includes the liquid crystal polymer powder and the polyamide acid. The liquid crystal polymer powder has a mass ratio of 20 % to 30 % in the solid content. The polyamide acid has a mass ratio of 70 % to 80 % in the solid content. The polyamide acid includes a liquid crystal structure. A method for preparing the polymer dispersion, a polymer composite film, and an application of the polymer composite film are also disclosed.

Description

Polymer dispersion liquid and preparation method thereof, polymer composite membrane and application thereof

The invention relates to the technical field of polymer material preparation, in particular to a preparation method of a polymer dispersion liquid, a polymer composite membrane and its application.

Signal transmission losses in printed circuit boards are partly due to losses caused by dielectric layers. The losses due to the dielectric layer are generally related to the dielectric constant and dielectric loss factor of the dielectric layer material. In addition, the polarity of the dielectric layer material will affect the stability of electron transport in the wire. If the polarity of the molecular structure in the insulating layer material is too large, after the circuit board is polarized, the electrons in the wire will be attracted by the dielectric layer, seriously affecting the electrons. Transmission stability. Therefore, how to effectively design the polymer structure of the dielectric layer, reduce the dielectric loss of the polymer material of the dielectric layer, and achieve a good insulating effect will become an important issue.

Currently, liquid-crystalline polymer (LCP) materials are widely used in printed circuit boards because of their liquid crystal structure and low dielectric loss. However, the solid content and viscosity of the LCP material are low, and the film needs to be formed under solvent-free and high-temperature conditions. The film-forming process has many restrictions, and it is also difficult to form a copper-clad laminate by laminating it with a copper plate after film-forming.

In order to solve the above technical problems, the present invention proposes a polymer dispersion and a preparation method thereof.

In addition, the present invention also proposes a polymer composite film prepared from the above-mentioned polymer dispersion and its application.

The present invention provides a polymer dispersion liquid, which includes liquid crystal polymer powder, polyamide acid and a solvent, the solid content of the polymer dispersion liquid includes the polyamide acid and the liquid crystal polymer powder, and the The weight percentage of the liquid crystal polymer powder in the solid content of the polymer dispersion is 20% to 30%, and the weight percentage of the polyamic acid in the solid content of the polymer dispersion is 70% to 30%. 80%, the polyamic acid is polymerized from two diamine monomers and two dianhydride monomers, and the two diamine monomers and the two dianhydride monomers both contain liquid crystal structures and Flexible structure.

In the embodiment of the present application, the particle size of the liquid crystal polymer powder is less than or equal to 3 μm.

In the embodiment of the present application, the solid content of the polymer dispersion is 25% to 35%, and the viscosity is 40000 cps to 50000 cps.

In the embodiment of the present application, the liquid crystal polymer powder includes an aromatic liquid crystal polyester.

The present invention also provides a preparation method of the polymer dispersion, comprising the following steps:

Provide a polyamic acid solution, the polyamic acid solution includes polyamic acid and a solvent, and the polyamic acid is polymerized from two diamine monomers and two dianhydride monomers, and the two Both the diamine monomer and the two dianhydride monomers contain a liquid crystal structure and a flexible structure, respectively.

And, adding liquid crystal polymer powder to the polyamic acid solution, and mixing to obtain the polymer dispersion liquid.

Wherein, the solid content of the polymer dispersion liquid includes the polyamic acid and the liquid crystal polymer powder, and the weight percentage of the liquid crystal polymer powder in the solid content of the polymer dispersion liquid is 20%. %~30%, the weight percentage of the polyamide acid in the solid content of the polymer dispersion liquid is 70%~80%.

In the embodiment of the present application, the average particle size of the liquid crystal polymer powder is less than or equal to 3 μm.

In the embodiment of the present application, the solid content of the polymer dispersion is 25% to 35%, and the viscosity is 40000 cps to 50000 cps.

In the embodiment of the present application, the liquid crystal polymer powder includes an aromatic liquid crystal polyester.

In the embodiment of the present application, the diamine monomer containing a liquid crystal structure includes p-aminophenyl p-aminobenzoate, 1,4-bis(4-aminophenoxy)benzene and di-p-aminophenyl terephthalate one or more of them.

The flexible structure-containing diamine monomers include 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 1,3-bis( One or more of 4'-aminophenoxy)benzene and 1,3-bis(3-aminophenoxy)benzene.

In the embodiment of the present application, the dianhydride monomer containing a liquid crystal structure includes 3,3',4,4'-biphenyltetracarboxylic dianhydride, p-phenylbis(trimellitate) dianhydride, and cyclic dianhydride. Hexane-1,4-diylbis(methylene)bis(ethyl 1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate).

The flexible structure-containing dianhydride monomer includes one or more of 4,4'-oxybisphthalic anhydride and bisphenol A-type diether dianhydride.

The present invention also provides a polymer composite film, the polymer composite film is prepared by heating the above-mentioned polymer dispersion liquid, the polymer composite film includes liquid crystal polymer crystals and polyimide crystals, the liquid crystal polymer The polymer crystals and the polyimide crystals are cross-linked with each other to form a network structure.

In the embodiment of the present application, the weight percentage of the liquid crystal polymer crystals in the polymer composite film is 20% to 30%.

In the embodiment of the present application, the polymer composite film is an anisotropic thermoplastic film.

The present invention also provides a copper clad laminate, the copper clad laminate comprising copper foil and a polymer composite film laminated on at least one surface of the copper foil, the polymer composite film comprising the above polymer composite film.

Compared with the prior art, the polymer dispersion liquid provided by the present invention can effectively improve the dispersion liquid by mixing the liquid crystal polymer powder with the thermoplastic polyamide containing both liquid crystal structure and flexible structure to form a dispersion liquid. The solid content and viscosity, and the stability of the formed dispersion liquid is good, which is conducive to the film formation of the dispersion liquid. The network structure is formed by the crystalline cross-linking points, which effectively reduces the Df and thermal expansion coefficient of the copper clad laminate, and at the same time improves the mechanical properties of the polymer composite film.

The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The names of technical means used in the description of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

The embodiments described below and features in the embodiments may be combined with each other without conflict.

The invention provides a polymer dispersion liquid, the polymer dispersion liquid includes liquid crystal polymer powder (LCP powder), polyamic acid and a solvent, and the solid component of the polymer dispersion liquid includes the polyamic acid and the liquid crystal polymer powder, the weight percentage of the liquid crystal polymer powder in the solid content of the polymer dispersion is 20% to 30%, and the polyamide acid in the polymer dispersion The weight percentage of the solid content is 70% to 80%. The polyamic acid is formed by polymerizing two diamine monomers and two dianhydride monomers, and both of the two diamine monomers and the two dianhydride monomers respectively contain a liquid crystal structure and a flexible structure.

In this embodiment, the average particle size of the liquid crystal polymer powder is less than or equal to 3 μm.

In this embodiment, the solid content of the polymer dispersion liquid is 25% to 35%, and the viscosity is 40000 cps to 50000 cps. By adding the liquid crystal polymer powder, the liquid crystal polymer powder is insoluble but can be dispersed in the solvent, so the viscosity of the polymer dispersion can be effectively increased, thereby improving the stability of the dispersion, which is beneficial to the subsequent film formation.

In this embodiment, the liquid crystal polymer powder includes, but is not limited to, aromatic liquid crystal polyester.

In this embodiment, the solvent includes but is not limited to N-methylpyrrolidone (NMP).

The present invention also provides a preparation method of the polymer dispersion, comprising the following steps:

The first step is to synthesize a polyamide solution.

Wherein, the polyamic acid is formed by polymerizing two kinds of diamine monomers and two kinds of dianhydride monomers, and the two kinds of the diamine monomers and the two kinds of the dianhydride monomers contain liquid crystal structure and flexibility respectively. structure.

In this embodiment, the diamine monomer containing a liquid crystal structure includes, but is not limited to, p-aminophenyl p-aminobenzoate (APAB), 1,4-bis(4-aminophenoxy)benzene (ABHQ) and terephthalic acid. One or more of di-p-aminophenyl formate (BPTP). Diamine monomers containing flexible structures include but are not limited to 4,4'-diaminodiphenyl ether (ODA), 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (BAPP) One or more of 1,3-bis(4'-aminophenoxy)benzene (TPE-R) and 1,3-bis(3-aminophenoxy)benzene (TPE-M).

In this embodiment, the liquid crystal structure-containing dianhydride monomers include, but are not limited to, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), p-phenylbis(trimellitate) dianhydride (TAHQ) and ethyl cyclohexane-1,4-diylbis(methylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate) (TA -CHDM) one or more. The dianhydride monomers containing flexible structures include, but are not limited to, one or more of 4,4'-oxydiphthalic anhydride (ODPA) and bisphenol A diether dianhydride (BPADA).

In this embodiment, the combination of diamine and dianhydride in the four monomers is made random, and the obtained polyamic acid is a mixture of a series of polyamic acid with different molecular structures. Specifically, the structural formula of the concrete product that adopts diamine to be APAB and TPE-R, and dianhydride is provided below for TAHQ and BPADA is exemplified as follows:

Structural formula I:

Structural formula II:

Structural formula III:

In this embodiment, the addition ratio of the diamine monomer and the dianhydride monomer is preferably 1:1.

In this embodiment, the solvent includes but is not limited to N-methylpyrrolidone (NMP).

In this embodiment, the diamine monomer and the dianhydride monomer are reacted at room temperature for about 48 hours to form a polyamic acid block copolymer. The solid content of the polyamide solution is 20wt%-30wt%.

In the second step, the liquid crystal polymer powder is added to the polyamic acid solution, and mixed to obtain the polymer dispersion. The solid content of the polymer dispersion includes the polyamic acid and the liquid crystal polymer powder, and the weight percentage of the liquid crystal polymer powder in the solid content of the polymer dispersion is 20%~ 30%, and the weight percentage of the polyamic acid in the solid content of the polymer dispersion is 70% to 80%.

In this embodiment, the particles of the liquid crystal polymer powder are added to the polyamic acid solution, and the liquid crystal polymer powder is insoluble but can be uniformly dispersed in the solution to form the polymer dispersion liquid. The average particle size of the liquid crystal polymer powder is less than or equal to 3 μm, the liquid crystal polymer powder of this size can better contact the polyamide acid, improve the contact area between the two, and at the same time is conducive to the powder The uniform dispersion of the bulk particles in the polymer dispersion liquid facilitates subsequent coating and film formation. If the average particle size of the liquid crystal polymer powder is too large, the polymer dispersion is prone to sedimentation, and the thickness of the liquid crystal polymer powder is likely to be uneven during subsequent coating and film formation. The polyamide acid cannot be fully contacted, resulting in failure to form a homogeneous film subsequently.

In this embodiment, the solid content of the polymer dispersion liquid is 25% to 35%, and the viscosity is 40000 cps to 50000 cps. By adding liquid crystal polymer powder to the thermoplastic polyamide solution to form a uniformly mixed dispersion, the solid content and viscosity of the dispersion can be effectively increased, which is beneficial to subsequent film formation.

In this embodiment, the liquid crystal polymer powder includes, but is not limited to, aromatic liquid crystal polyester.

The present invention also provides a polymer composite membrane, which is prepared by heating the polymer dispersion as described above. 1A - 1B, during the process of heating and curing the dispersion liquid to form a film, the liquid crystal polymer crystal 1 corresponding to the liquid crystal polymer powder is melted to form a flowable melt, and the polyamide acid molecule 2 is heated and cyclized to form a polyamide The imine melt, the liquid crystal polymer melt is uniformly distributed in the polyimide melt, as shown in Figure 1A. And the liquid crystal polymer powder has a liquid crystal structure (ester group), and the polyimide also contains a liquid crystal structure (ester group), which can crystallize during the cooling process, and the liquid crystal polymer melt recrystallizes to form a liquid crystal polymer crystal again. 1. Polyimide crystals form polyimide crystals 3, as shown in Figure 1B. Since the two melts are uniformly mixed together, the two crystalline phases will also form a large number of physical crystalline cross-linking points, which connect the liquid crystal polymer crystalline phase and the polyimide crystalline phase to form a network The circuit structure, as shown in the enlarged view in FIG. 1B , the liquid crystal polymer crystal 1 and the polyimide crystal 3 are interspersed with each other to form a physical crystalline cross-linked network structure. The formed network structure effectively improves the mechanical properties of the polymer composite film, and at the same time reduces the coefficient of thermal expansion (CTE) of the polymer composite film, thereby improving the dimensional stability of the polymer composite film. In addition, when the polymer dispersion is formed, the liquid crystal polymer powder is uniformly distributed in the polyamic acid solution, and the average particle size of the liquid crystal polymer powder is very small. The body can be fully melted to form a uniform mixed melt with the polyimide melt. After the two melts are crystallized, two crystals are formed, and the two crystals are mixed to form a network structure, and the arrangement direction of the two crystals is anisotropic , thus endows the polymer composite membrane with anisotropic characteristics.

In this embodiment, the average particle size of the liquid crystal polymer powder is less than or equal to 3 μm. In the process of forming the dispersion liquid, the liquid crystal polymer powder of this size can better contact with the polyamic acid, improving the two At the same time, it is beneficial to increase the viscosity of the polymer dispersion liquid, so as to facilitate the coating of the polymer dispersion liquid to form a film. When the average particle size of the liquid crystal polymer powder is too large, the polymer dispersion is prone to sedimentation and the phenomenon of uneven thickness during subsequent coating and film formation. The liquid crystal polymer powder particles cannot be completely melted, resulting in inability to form a homogeneous film.

In this embodiment, the proportion of the two crystals can be adjusted by adjusting the contents of the liquid crystal polymer powder and the polyamic acid, thereby adjusting the mechanical properties and electrical properties of the composite film. In addition, the mechanical properties and electrical properties of the composite film can be further adjusted by adjusting the introduction of the liquid crystal structure during the synthesis of the polyamide.

In this embodiment, the liquid crystal polymer crystals 1 in the polymer composite film account for 20% to 30% by weight of the polymer composite film.

In this embodiment, the heating temperature is 350° C.˜370° C., and the heating time is 30 min˜60 min. The specific heating temperature may vary depending on the glass transition temperature of the actual polymer dispersion.

In this embodiment, the thermal expansion coefficient of the polymer composite film is less than or equal to 45ppm/°C, the tensile strength is greater than or equal to 130MPa, and the elongation is greater than or equal to 18%.

Specifically, the film-forming process of the polymer composite film is as follows: coating the polymer dispersion liquid with a thickness greater than or equal to 50 μm on a release substrate, and then coating the release substrate coated with the polymer dispersion liquid film layer Baking and heating through an oven, usually in the range of 350°C to 370°C for 30min to 60min, to obtain the polymer composite film. At the above temperature, the liquid crystal polymer powder particles will melt and become a melt, which can better form a homogeneous film.

2A-2C, the present invention also provides a preparation process of the copper clad laminate 100, which specifically includes the following steps:

Referring to FIG. 2A , a copper foil 10 is provided. The thickness of the copper foil 10 can be selected according to actual use requirements. Specifically, in this embodiment, the thickness of the copper foil 10 is 12 μm.

Referring to FIG. 2B , the polymer dispersion liquid is coated on a surface of the copper foil 10 to form a polymer dispersion liquid film 30 to obtain an intermediate. Specifically, in this embodiment, the thickness of the polymer dispersion liquid film 30 is is 50 μm.

Referring to FIG. 2C , the intermediate is heated in an oven to cure the polymer dispersion liquid film 30 to form a polymer composite film 20 , and the copper clad laminate 100 is obtained. In this embodiment, the polymer dispersion liquid film 30 is heated in the range of 350° C. to 370° C. for 30 min to 60 min to obtain the polymer composite film 20 .

The copper clad laminate 100 includes a copper foil 10 and a polymer composite film 20 laminated on the surface of the copper foil 10 , and the polymer composite film 20 is the polymer composite film as described above.

In this embodiment, the copper clad laminate 100 has excellent electrical properties. The electrical performance test is performed at a frequency of 10 GHz. It can be seen that the copper clad laminate has excellent dielectric loss factor (Df) and dielectric constant (Dk), wherein Dk is preferably 3.3 to 3.2, and Df is preferably 0.002 to 0.001.

In this embodiment, the peel strength of the polymer composite film 20 on the surface of the copper foil 10 is preferably greater than or equal to 0.7 kgf/cm. In the heat resistance test, the above-mentioned polymer composite film has good heat resistance under the condition of 288°C/10sec.

In addition, the double-sided copper clad laminate can also be prepared by the above method.

The present invention also provides another method for preparing a copper clad laminate. First, a polymer composite film is prepared, and then the polymer composite film is attached to at least one side of the copper foil and hot-pressed to form the copper clad laminate. The specific conditions of the hot-press bonding are as follows: the hot-pressing temperature is 350°C-370°C, the pressure per unit area is 30-80 kgf/mm ² , and the hot-pressing reagent is within 10-30 minutes. Specifically, single-sided or double-sided copper clad laminates can be prepared by this method. The solution of the present application will be further described below with specific examples.

The following Synthesis Examples 1-5 are all specific synthesis methods of the polyamic acid solution, and the solid content of the synthesized polyamic acid solution is 20wt%~30wt%. After synthesizing the polyamic acid solution, coat a 50 μm thick polyamic acid solution on a 12 μm copper plate, and bake it at 350℃~370℃ for 30min~60min, remove the solvent and cyclize the polycarbamic acid to form a polycarbamic acid The imine is melted, and then cooled to form a polyimide film, thereby obtaining a copper clad laminate, and the mechanical properties and electrical properties of the copper clad laminate are tested.

Synthesis Example 1

NMP (243.8g) and TPE-M (0.1mol, 29.23g) were respectively added to the 500mL reaction flask, and after stirring until dissolved, BPADA (0.1 mol, 52.05g) was added and the reaction was stirred for 48 hours. Amino acid solution.

Synthesis Example 2

NMP (205.97g) and APAB (0.1mol, 22.83g) were respectively added to the 500mL reaction flask, and after stirring to dissolve, TAHQ (0.1mol, 45.83g) was added to stir the reaction for 48 hours, that is, the polyamide acid was configured. solution.

Synthesis Example 3

NMP (225.20 g) and TPE-M (0.1 mol, 29.2 g) were respectively added to the 500 mL reaction flask, and after stirring until dissolved, TAHQ (0.1 mol, 45.83 g) was added to stir the reaction for 48 hours, that is, the configuration was completed. Amino acid solution.

Synthesis Example 4

NMP (224.62g) and APAB (0.1mol, 22.83g) were respectively added to the 500mL reaction flask, and after stirring until dissolved, BPADA (0.1mol, 52.05g) was added to stir the reaction for 48 hours, that is, the polyamide acid was configured. solution.

Synthesis Example 5

NMP (224.91g), TPE-M (0.05mol, 14.61g) were respectively added to the 500mL reaction flask, and after stirring to dissolve, TAHQ (0.05mol, 22.93g) was added and stirred for 1 hour, and then APAB ( 0.05mol, 11.41g), after stirring to dissolve, then add BPADA (0.05mol, 26.02g) to stir and react for 48 hours, that is, the configuration completes the polyamide solution.

Table 1 shows the specific proportions of the raw materials for preparing the polyamide acid and the test results of the corresponding copper clad laminates.

Table 1 Polyamide project Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 Synthesis Example 4 Synthesis Example 5 Diamine (mol%) APAB — 50 — 50 25 TPE-M 50 — 50 — 25 Dianhydride (mol%) TAHQ — 50 50 — 25 BPADA 50 — — 50 25 Whether it contains liquid crystal structure none Have Have Have Have Viscosity (cps) 20,000 to 30,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 Peel strength (kgf/cm) 1.3 0.27 0.81 0.93 1.33 Ts (°C) 230 >400 335 310 269 CTE value (ppm/℃) 71.1 13.5 29.3 38.1 57.1 Film formability (no voids) PASS PASS PASS PASS PASS Tensile Strength(Mpa) 85 213 167 142 110 Elongation (%) 19.3 5.3 8.9 10.1 15.1 Tin bleaching test (288℃/10s) NG PASS PASS PASS PASS Dk (10GHz) 3.4 3.3 3.3 3.2 3.0 Df (10GHz) 0.018 0.002 0.006 0.009 0.003

Note: Ts is the thermal processing temperature of polyimide, where Ts is between the glass transition temperature Tg and the melting temperature Tm.

The following examples 1-3 are all specific synthesis methods of polymer dispersions, and the solid content of the synthesized polymer dispersions is 25wt% to 35wt%. After synthesizing the polymer dispersion, coat the polymer dispersion with a thickness of 50μm on a 12μm copper plate, and bake at 350℃~370℃ for 30min~60min, remove the solvent and melt the polyimide and liquid crystal polymer powder , and then cooled to form a polymer composite film to obtain a copper clad laminate, and the mechanical properties and electrical properties of the copper clad laminate were tested.

Example 1

In a 100ml reaction flask, add 10g of the polyamide solution synthesized in Synthesis Example 5 and 0.625g of LF31-P powder in turn, and stir for 6 hours to completely disperse the powder in the polyamide solution to obtain a polymer dispersion. .

Example 2

In a 100ml reaction flask, add 10g of the polyamide solution synthesized in Synthesis Example 5 and 0.833g of the LF31-P powder in turn, and stir for 6 hours to completely disperse the powder in the polyamide solution to obtain a polymer dispersion. .

Example 3

In a 100ml reaction flask, add 10 g of the polyamic acid solution synthesized in Synthesis Example 5 and 1.07 g of the LF31-P powder in turn, and stir for 6 hours to completely disperse the powder in the polyamic acid solution to obtain a polymer dispersion. .

Table 2 shows the specific proportions of the raw materials for preparing the polymer dispersion and the test results of the copper clad laminate with the polymer composite film.

Table 2 Polyamide project Example 1 Example 2 Example 3 Solid content (wt%) LF31-P 20 25 30 Synthesis Example 5 80 75 70 Whether it contains liquid crystal structure Have Have Have Viscosity (cps) 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 Peel strength (kgf/cm) 0.93 0.85 0.78 CTE value (ppm/℃) 43.2 37.2 31.2 Film formability (no voids) PASS PASS PASS Tensile Strength(Mpa) 133 140 145 Elongation (%) 18.3 18.9 19.6 Tin bleaching test (288℃/10s) PASS PASS PASS Dk (10GHz) 3.2 3.3 3.3 Df (10GHz) 0.002 0.001 0.001

The following Comparative Examples 1-8 synthesized liquid crystal polymer dispersion and polymer dispersion respectively. After synthesizing the dispersion, the corresponding solution with a thickness of 50 μm was coated on a 12 μm copper plate, and then baked at 350 ℃ ~ 370 ℃ for 30min ~ 60min, The solvent is removed, heated, and then cooled to form a corresponding film material, thereby obtaining a corresponding copper clad laminate, and the mechanical properties and electrical properties of the above copper clad laminate are tested.

Comparative Example 1

Add 3.5 g of LF31-P powder and 31.5 g of NMP to a 100-ml reaction flask in sequence, and stir for 6 hours to completely disperse the powder in the solvent to obtain the LF31-P dispersion.

Comparative Example 2

In a 100ml reaction flask, sequentially add 10g of the polyamide solution synthesized in Synthesis Example 1 and 0.625g of LF31-P powder, and stir for 6 hours to completely disperse the powder in the polyamide solution to obtain a polymer dispersion. .

Comparative Example 3 In a 100ml reaction flask, 10 g of the polyamide solution synthesized in Synthesis Example 2 and 0.625 g of LF31-P powder were added in turn, and stirred for 6 hours to completely disperse the powder in the polyamide solution, and high Molecular dispersion.

Comparative Example 4 In a 100ml reaction flask, 10 g of the polyamide solution synthesized in Synthesis Example 3 and 0.625 g of LF31-P powder were added in sequence, and stirred for 6 hours to completely disperse the powder in the polyamide solution. Molecular dispersion.

Comparative Example 5

In a 100ml reaction flask, sequentially add 10g of the polyamide solution synthesized in Synthesis Example 4 and 0.625g of LF31-P powder, and stir for 6 hours to completely disperse the powder in the polyamide solution to obtain a polymer dispersion. .

Comparative Example 6

In a 100ml reaction flask, add 10 g of the polyamic acid solution synthesized in Synthesis Example 4 and 1.07 g of the LF31-P powder in turn, and stir for 6 hours to completely disperse the powder in the polyamic acid solution to obtain a polymer dispersion. .

Comparative Example 7

In a 100ml reaction flask, sequentially add 10 g of the polyamide solution synthesized in Synthesis Example 5 and 0.441 g of LF31-P powder, and stir for 6 hours to completely disperse the powder in the polyamide solution to obtain a polymer dispersion. .

Comparative Example 8

In a 100ml reaction flask, sequentially add 10 g of the polyamic acid solution synthesized in Synthesis Example 5 and 1.35 g of LF31-P powder, and stir for 6 hours to completely disperse the powder in the polyamic acid solution to obtain a polymer dispersion. .

Table 3 shows the specific proportions of the raw materials for preparing the liquid crystal polymer dispersion and the polymer dispersion and the test results of the corresponding copper clad laminates.

table 3 project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Solid content (wt%) LF31-P 100 20 20 20 20 30 15 35 Synthesis Example 1 — 80 — — — — — — Synthesis Example 2 — — 80 — — — — — Synthesis Example 3 — — — 80 — — — — Synthesis Example 4 — — — — 80 70 — — Synthesis Example 5 — — — — — — 85 65 Whether it contains liquid crystal structure Have none Have Have Have Have Have Have Viscosity (cps) 3350 20,000 to 30,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 40,000 to 50,000 Peel strength (kgf/cm) — 0.13 0.21 0.64 0.71 0.53 1.1 0.65 CTE value (ppm/℃) — 62.1 10.3 21.3 29.2 23.2 48.1 29.5 Film formability (no voids) Unable to form film PASS PASS PASS PASS PASS PASS PASS Tensile Strength(Mpa) — 57 223 180 161 175 127 151 Elongation (%) — 2.5 7.1 10.1 12.5 13.1 17.1 19.8 Tin bleaching test (288℃/10s) — NG PASS PASS PASS PASS PASS PASS Dk (10GHz) 3.5 3.4 3.4 3.4 3.3 3.4 3.2 3.4 Df (10GHz) 0.0007 0.011 0.002 0.003 0.005 0.003 0.003 0.001

Note: The corresponding test standards in Table 1-3 are: the test standard for peel strength is IPC-TM650 2.4.9, the test standard for tin bleaching test is IPC-TM650 2.4.13, and the test standard for tensile strength and elongation is ASTM D638.

The LF31-P powder in Table 2-3 was purchased from Nippon Oil & Energy Corporation (JXTG), the average particle size was less than 3 μm, and it was a full ester-based crystalline polymer.

The test results show that: from Comparative Example 1, it can be seen that LF31-P powder (particle size < 3 μm, full ester-based crystalline polymer) is dispersed in NMP, but after high temperature sintering, it cannot form a film by itself.

It can be seen from synthesis examples 1 to 5 that during the synthesis of polyamide acid, adding a monomer containing a liquid crystal structure (specifically an ester group) can make the copper clad laminate formed by polyamide acid have excellent dielectric loss factor Df, And the more the proportion of liquid crystal structure in the polyamide molecular chain, the better the Df value. In Synthesis Example 2, the diamine monomer is APAB, and the dianhydride monomer is TAHQ. Both monomers contain liquid crystal structure, so that the polyamide The content of the liquid crystal structure in the molecular chain of the amino acid is the most, and the Df value is lower than that of the synthesis examples 3-5, but the corresponding Dk value is higher. At the same time, the peel strength of the composite film on the copper clad laminate decreases, and the increase of the liquid crystal structure will reduce the bonding force between the composite film and the copper foil, thereby reducing the peel strength. In Synthesis Examples 3 to 5, there are flexible structures (specifically -O-) blended in the same proportion, the Df value is higher, and the Dk value is decreased. At the same time, the addition of the flexible structure improves the adhesion between the composite film and the copper foil, thereby peeling off Strength is increased. Among them, the diamine monomer and dianhydride monomer containing liquid crystal structure added in Synthesis Example 5 adopt the method of stepwise addition and polymerization, which increases the dispersibility of the liquid crystal structure, thereby obtaining excellent Dk value and Df value, while maintaining excellent peel strength.

Examples 1 to 3 use the polyamide acid synthesized in Synthesis Example 5. Compared with Synthesis Example 5, Examples 1 to 3 add 20wt% to 30wt% of full ester groups and are insoluble in solvents due to the addition of LF31-P. Powder (particle size <3μm). The addition of liquid crystal polymer powder can increase the number of crystalline structures and generate a large number of physical crystalline cross-linked structures, thereby improving the mechanical properties of the polymer composite film, and the prepared copper clad laminates have excellent Df and Dk, dielectric loss factor (Df) and coefficient of thermal expansion (CTE) decreased with the increase of LF31-P powder addition. In addition, the peel strength of the polymer composite film reached the target value (peel strength greater than or equal to 0.7 kgf/cm).

Compared with Example 1, although the polymer dispersions corresponding to Comparative Examples 3 to 5 are added with the same content of liquid crystal polymer powder, the addition of liquid crystal polymer powder can increase the number of crystalline structures and produce a physical crystalline cross-linked structure. , thereby improving the mechanical properties of the polymer composite film, the Df of the copper clad laminate is also reduced, but the peel strength and thermal expansion coefficient of the polymer composite film are reduced, and the Dk of the copper clad laminate is increased. The diamine monomers and dianhydride monomers used in the preparation of polyamic acid are both monomers containing liquid crystal structures, without a flexible structure, which leads to a decrease in the degree of freedom of the polyamic acid molecule and a decrease in the flexibility of the molecular chain, which makes the polymer The compatibility of the amide acid molecule with the liquid crystal polymer powder becomes poor, resulting in a decrease in the thermal expansion coefficient and peel strength of the polymer composite film, and an increase in the Dk of the copper clad laminate. In Comparative Examples 4~5, the diamine monomer or dianhydride monomer used to prepare the polyamide acid was introduced into the liquid crystal structure alone, and the distribution of the crystalline phase in the network structure decreased in uniformity compared with Example 1, thereby reducing the The number of physical crystalline cross-linking points between the liquid crystal polymer crystalline phase and the polyimide crystalline phase causes the Df, peel strength and thermal expansion coefficient of the polymer composite film to decrease, while the Dk of the copper clad laminate increases and exceeds the target value (Dk is preferably between 3.2 and 3.3).

Compared with Example 3, although the same content of liquid crystal polymer powder was added in Comparative Example 6, the number of crystalline structures and the physical crystalline cross-linking structure could be increased, so that the mechanical properties of the polymer composite film were improved, and the Df value of the copper clad laminate was improved. At the same time, the peel strength of the polymer composite film decreased, and the Dk value of the copper clad laminate increased and exceeded the target value.

However, the polyamic acid of Synthesis Example 1 used in Comparative Example 2 has no liquid crystal structure in the polyamic acid of Synthesis Example 1, indicating that the polyamic acid without liquid crystal structure has poor compatibility with LF31-P powder, so The mechanical properties of the polymer composite film are reduced, and the peel strength is greatly reduced.

From Examples 1 to 3 and Comparative Examples 7 to 8, it can be seen that the increase in the amount of LF31-P powder added is beneficial to the decrease of the Df value of the copper clad laminate, but the Dk value of the copper clad laminate will increase and the peel strength of the polymer composite film will decrease. . In Comparative Example 7, the amount of LF31-P powder added was too small, and the Df value did not reach the target value (Df is preferably between 0.001 and 0.002). In Comparative Example 8, the amount of LF31-P powder added was too large, and the Dk value and peel strength exceeded the target value (Dk is preferably between 3.2 and 3.3).

To sum up, the polymer dispersion provided by the present invention can effectively increase the solid content of the dispersion by mixing the liquid crystal polymer powder with the thermoplastic polyamide containing both a liquid crystal structure and a flexible structure to form a dispersion. and viscosity, and the dispersion liquid formed has good stability, which is conducive to the film formation of the dispersion liquid. The crystalline cross-linking points form a network structure, which effectively reduces the Df and thermal expansion coefficient of the copper clad laminate, and at the same time improves the mechanical properties of the polymer composite film.

The descriptions of the above embodiments and comparative examples are only used to help understand the method of the present invention and its core idea; in addition, for those of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical idea of the present invention , and all these changes and deformations should belong to the protection scope of the claims of the present invention.

100: Layer CCL 10: Copper plate 20: Polymer composite membrane 30: Polymer dispersion liquid film 1: Liquid crystal polymer crystal 2: Polyamide molecule 3: Polyimide crystals

1A-1B are schematic diagrams of crystallization during the heating process of the polymer dispersion provided by an embodiment of the present invention.

2A to 2C are a flow chart of the preparation of the copper clad laminate provided by an embodiment of the present invention.

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

1: Liquid crystal polymer crystal

3: Polyimide crystals

Claims (14)

A polymer dispersion liquid, which includes liquid crystal polymer powder, polyamide acid and a solvent, the solid content of the polymer dispersion liquid includes the polyamide acid and the liquid crystal polymer powder, the liquid crystal polymer powder The weight percentage of the polymer powder in the solid content of the polymer dispersion is 20% to 30%, and the weight percentage of the polyamic acid in the solid content of the polymer dispersion is 70% to 80%. %, the polyamic acid is polymerized from two diamine monomers and two dianhydride monomers, and both of the two diamine monomers and the two dianhydride monomers contain liquid crystal structure and flexibility, respectively. structure. The polymer dispersion liquid according to claim 1, wherein the particle size of the liquid crystal polymer powder is less than or equal to 3 μm. The polymer dispersion liquid according to claim 1, wherein the polymer dispersion liquid has a solid content of 25% to 35%, and a viscosity of 40000cps to 50000cps. The polymer dispersion liquid according to claim 1, wherein the liquid crystal polymer powder includes an aromatic liquid crystal polyester. A preparation method of a polymer dispersion, wherein, comprising the following steps: Provide a polyamic acid solution, the polyamic acid solution includes polyamic acid and a solvent, and the polyamic acid is polymerized from two diamine monomers and two dianhydride monomers, and the two Both the diamine monomer and the two dianhydride monomers contain a liquid crystal structure and a flexible structure, respectively; and adding liquid crystal polymer powder to the polyamic acid solution, and mixing to obtain the polymer dispersion, Wherein, the solid content of the polymer dispersion liquid includes the polyamic acid and the liquid crystal polymer powder, and the weight percentage of the liquid crystal polymer powder in the solid content of the polymer dispersion liquid is 20%. %~30%, the weight percentage of the polyamide acid in the solid content of the polymer dispersion liquid is 70%~80%. The method for preparing a polymer dispersion liquid according to claim 5, wherein the average particle diameter of the liquid crystal polymer powder is less than or equal to 3 μm. The method for preparing a polymer dispersion liquid according to claim 5, wherein the polymer dispersion liquid has a solid content of 25% to 35%, and a viscosity of 40000 cps to 50000 cps. The method for preparing a polymer dispersion according to claim 5, wherein the liquid crystal polymer powder comprises an aromatic liquid crystal polyester. The method for preparing a polymer dispersion liquid according to claim 5, wherein the diamine monomer containing a liquid crystal structure comprises p-aminophenyl p-aminobenzoate, 1,4-bis(4-aminophenoxy) One or more of benzene and di-p-aminophenyl terephthalate; The flexible structure-containing diamine monomers include 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 1,3-bis( One or more of 4'-aminophenoxy)benzene and 1,3-bis(3-aminophenoxy)benzene. The method for preparing a polymer dispersion liquid according to claim 5, wherein the dianhydride monomer containing a liquid crystal structure comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride, p-phenylenedi (Trimellitate)dianhydride and cyclohexane-1,4-diylbis(methylene)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate ethyl acetate); The flexible structure-containing dianhydride monomer includes one or more of 4,4'-oxybisphthalic anhydride and bisphenol A-type diether dianhydride. A polymer composite film, wherein the polymer composite film is prepared by heating the polymer dispersion according to any one of claims 1 to 4, and the polymer composite film includes liquid crystal polymer crystals and polyamides The imine crystal, the liquid crystal polymer crystal and the polyimide crystal are cross-linked with each other to form a network structure. The polymer composite film according to claim 11, wherein the liquid crystal polymer crystals account for 20% to 30% by weight of the polymer composite film. The polymer composite film according to claim 11, wherein the polymer composite film is anisotropic. A copper clad laminate, comprising copper foil and a polymer composite film laminated on at least one surface of the copper foil, the polymer composite film comprising the polymer composite film according to any one of claims 11 to 13.

Images