TWI668299B - Modified liquid crystal polymer, polymeric layer, and method for making the same - Google Patents

Abstract

A modified liquid crystal polymer, the chemical structure of the modified liquid crystal polymer is or Wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from at least one of a chain alkane group and a chain alkoxy group, and the chain alkoxy group is bonded to the benzene by an oxygen atom On the basis, p and q are natural numbers greater than 1, and the modified liquid crystal polymer has a melting point of 220 to 300 degrees Celsius. In addition, the present invention also provides a method for preparing the above modified liquid crystal polymer, a polymer film using the modified liquid crystal polymer, and a preparation method thereof.

Description

Modified liquid crystal polymer, polymer film and corresponding preparation method

The present invention relates to a modified liquid crystal polymer, a method for preparing the modified liquid crystal polymer, a polymer film using the liquid crystal polymer, and a method for preparing the polymer film.

In the era of big data, the information processing of electronic products continues to develop in the direction of high-frequency signal transmission and high-speed digitalization. To ensure that the electronic product has good signal transmission quality under the condition of high-frequency signal transmission, it is required that the transmission line in the conductive copper foil of the flexible circuit board and the electronic components connected thereto are in an impedance matching state to avoid signal reflection. , scattering, attenuation, and delay. The dielectric constant and dielectric loss factor of the material of the adhesive layer in contact with the conductive line in the flexible circuit board are an important factor affecting the impedance matching of the high frequency transmission. The polymer film layer used in the flexible printed circuit board in the prior art often uses a liquid crystal polymer film formed by a liquid crystal polymer, and the liquid crystal polymer film has a low dielectric loss due to the neat arrangement of the polymer structure. Factor Df, of course, the liquid crystal polymer in the prior art has poor film forming processing characteristics when the liquid crystal polymer film is formed.

In view of the above, it is necessary to provide a modified liquid crystal polymer which is advantageous for high-frequency transmission of signals and has good film formability.

Further, it is also necessary to provide a preparation method for preparing the above modified liquid crystal polymer.

In addition, it is also necessary to provide a polymer film obtained by applying the modified liquid crystal polymer and a preparation method thereof.

A modified liquid crystal polymer, the chemical structure of the modified liquid crystal polymer is or

Wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from at least one of a chain alkane group and a chain alkoxy group, and the chain alkoxy group is bonded to the benzene by an oxygen atom On the basis, p and q are natural numbers greater than 1, and the modified liquid crystal polymer has a melting point of 220 to 300 degrees Celsius.

A method for preparing a modified liquid crystal high molecular polymer, comprising the steps of: mixing 4-toluenesulfonium chloride, N-methylpyrrolidone and pyridine to form a first composition; to 4-hydroxybenzoic acid, 6- Hydroxy-2-naphthoic acid is separately added with pyridine, so that 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are respectively dissolved and dispersed in pyridine to prepare a first solution and a second solution, and the structural formula is a mixture of a diphenolic compound and terephthalic acid or a hydroquinone and a structural formula Pyridine is added to the mixture of diacid compounds, and the mixture is dissolved and dispersed in pyridine to obtain a third solution, wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from a chain alkane group and a chain. At least one of the alkoxy groups, and the chain alkoxy group is bonded to the phenyl group by an oxygen atom; adding the first solution to the first composition, mixing uniformly, and then heating Reacting to prepare a second composition; adding the second solution to the second composition under heating to obtain a third composition; adding the third solution to the first portion under heating The fourth composition is obtained by reacting in the third composition, wherein the chemical composition of the fourth composition is dissolved or The modified liquid crystal high molecular polymer, wherein p and q are natural numbers greater than 1; the fourth composition is added to methanol or ethanol to precipitate the modified liquid crystal polymer to form a precipitate. The modified liquid crystal polymer is obtained by separating and cleaning, and the modified liquid crystal polymer has a melting point of 220 to 300 degrees Celsius.

A polymer film obtained by baking and curing a liquid crystal polymer containing modified as described above, wherein the polymer film includes the modified liquid crystal polymer The chemical cross-linking road structure formed by the reaction.

A method for preparing a polymer film produced by using the modified liquid crystal polymer as described above, comprising the steps of: baking and curing a resin composition comprising the modification The liquid crystal polymer and the solvent, and the chemical cross-linking structure formed by the crosslinking reaction between the modified liquid crystal polymer.

The polymer film obtained by the modified liquid crystal polymer of the present invention has a dielectric constant D _k and a dielectric loss D _f corresponding to a polymer film obtained by a liquid crystal polymer in the prior art. And, because the modified liquid crystal polymer is bonded The above two structures include a long-chain structure in which a chain alkane group and/or a chain alkoxy group are side chains, so that the modified liquid crystal polymer has a lower melting point, thereby The modified liquid crystal polymer in the resin composition can be dissolved in a solvent, so that the film composition of the resin composition at the time of forming the polymer film is better.

The modified liquid crystal high molecular polymer of the preferred embodiment of the present invention can be used in a substrate, a glue layer or a cover film of a circuit board (for example, a rigid flexible bonding board). The chemical structural formula of the modified liquid crystal polymer is or .

Wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from at least one of a chain alkane group and a chain alkoxy group, and the chain alkoxy group is bonded to the benzene by an oxygen atom On the base. Preferably, R ₁ , R ₂ , R ₃ and R ₄ are each selected from the group consisting of -C ₄ H ₉ , -OC ₄ H ₉ , -C ₆ H ₁₃ , -OC ₆ H ₁₃ , -C ₈ H ₁₇ and -OC ₈ At least one of H ₁₇ . In the present embodiment, the ratio range of x:y:z is (45 to 49): (45 to 49): (2 to 10). The ratio of m:n:r is (45~49): (45~49): (2~10). Preferably, the ratio of x:y:z is selected from at least one of 49:49:2, 48:48:4, 47:47:6, 46:46:8, and 45:45:10, m:n: The ratio of r is selected from at least one of 49:49:2, 48:48:4, 47:47:6, 46:46:8, and 45:45:10. p and q are natural numbers greater than one, respectively. The modified liquid crystal polymer has a melting point of 220 degrees Celsius to 300 degrees Celsius.

A preferred embodiment of the present invention further provides a method for preparing the above modified liquid crystal polymer, comprising the steps of: step S1, mixing 4-toluenesulfonium chloride, N-methylpyrrolidone and pyridine and standing to form a first composition.

In the present embodiment, the content relationship between 4-toluenesulfonium chloride, N-methylpyrrolidone and pyridine is not particularly limited, and it is only necessary to ensure uniform dispersion of the three substances.

In the present embodiment, the standing time is 30 minutes or more. Preferably, the standing time is 30 minutes.

Step S2, adding pyridine to 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, respectively, and a mixture of a diphenolic compound and terephthalic acid or a hydroquinone and a structural formula The pyridine is added to the mixture of the diacid compound, and the 4-hydroxybenzoic acid and the 6-hydroxy-2-naphthoic acid are respectively dissolved and dispersed in the pyridine to prepare the first solution and the second solution, and the mixture is in the pyridine. The third solution was prepared by dissolving and dispersing. Wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from at least one of a chain alkane group and a chain alkoxy group, and the chain alkoxy group is bonded to the benzene by an oxygen atom On the base. Preferably, R ₁ , R ₂ , R ₃ and R ₄ are each selected from the group consisting of -C ₄ H ₉ , -OC ₄ H ₉ , -C ₆ H ₁₃ , -OC ₆ H ₁₃ , -C ₈ H ₁₇ and -OC ₈ At least one of H ₁₇ . In the mixture, the mass ratio of the diphenolic compound to terephthalic acid or the mass ratio of hydroquinone to the diacid compound is 1:1.

In the present embodiment, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and the mixture are each dissolved and dispersed in pyridine by ultrasonic vibration. In other embodiments, the 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and the mixture may each be dissolved and dispersed in pyridine using other means such as agitation.

Step S3, adding the first solution in which the 4-hydroxybenzoic acid is dissolved to the first composition, mixing uniformly, and then stirring in a nitrogen atmosphere at 60 degrees Celsius to 100 degrees Celsius for 10 minutes or more. Second composition.

In the present embodiment, the mass ratio of 4-hydroxybenzoic acid to 4-toluenesulfonium chloride is 49:0.1.

Step S4, adding the second solution containing the 6-hydroxy-2-naphthoic acid to the second composition under a nitrogen atmosphere and a temperature of 60 degrees C to 100 degrees C, and pre-reacting for 30 minutes or more. A third composition is obtained.

The mass ratio of 4-hydroxybenzoic acid to 6-hydroxy-2-naphthoic acid was 1:1.

In step S5, the fourth solution in which the third solution in which the mixture is dissolved is added to the third composition for 24 hours or more under a nitrogen atmosphere and 60 degrees C to 100 degrees C to prepare a fourth composition. Wherein the modified liquid crystal polymer is dissolved in the fourth composition.

In the present embodiment, the mass ratio of 4-hydroxybenzoic acid to the mixture is from 45:10 to 49:2.

Preferably, the reaction time is 24 hours.

In step S6, the fourth composition is added to methanol or ethanol, and the modified liquid crystal polymer is precipitated to form a precipitate, which is then separated and cleaned to obtain the modified liquid crystal polymer.

In this embodiment, the precipitated liquid crystal polymer is obtained by suction filtration to obtain the modified liquid crystal polymer, and the precipitate is washed by methanol or ethanol to remove residual 4-toluenesulfonyl chloride, N. -methylpyrrolidone and pyridine.

Wherein, the reaction mechanism of the above method for forming the modified liquid crystal polymer is as follows:

A polymer film obtained by baking and curing a resin containing the modified liquid crystal polymer. Wherein, the polymer film includes a chemical cross-linking structure formed by a crosslinking reaction between the modified liquid crystal polymer.

In this embodiment, the baking curing temperature is 130 degrees Celsius to 150 degrees Celsius, and the baking curing time is 20 minutes to 40 minutes.

A method for preparing a polymer film, comprising the steps of: Step 1, providing a resin composition comprising the above modified liquid crystal polymer and a solvent. Wherein the solvent dissolves the liquid crystal polymer. In the embodiment, the viscosity of the resin composition is from 1000 cps to 2000 cps.

In the embodiment, the solvent is N-methylpyrrolidone. In other embodiments, the solvent may also be other organic solvents commonly used in the art to dissolve liquid crystal high molecular polymers.

In the second step, the polymer film is baked and cured to obtain the polymer film. Wherein, the polymer film includes a chemical cross-linking structure formed by a crosslinking reaction between the modified liquid crystal polymer.

In this embodiment, the baking curing temperature is 130 degrees Celsius to 150 degrees Celsius, and the baking curing time is 20 minutes to 40 minutes.

Due to the bonding of the modified liquid crystal polymer The above two structures include a long-chain structure in which a chain alkane group and/or a chain alkoxy group are side chains, so that the modified liquid crystal polymer has a lower melting point, thereby The modified liquid crystal polymer in the resin composition can be dissolved in a solvent, so that the film composition of the resin composition at the time of forming the polymer film is better.

The invention will be specifically described below by way of examples and comparative examples.

Example 1

0.1 g of 4-toluenesulfonium chloride, 50 mL of N-methylpyrrolidone and 3 mL of pyridine were mixed and allowed to stand for 30 minutes to obtain a first composition.

0.2 g of pyridine was added to 0.49 mol of 4-hydroxybenzoic acid and the 4-hydroxybenzoic acid was dissolved and dispersed in pyridine by ultrasonic shaking to obtain a first solution, and 0.2 g of pyridine was added to 0.49 mol of 49 g of 6 -hydroxy-2-naphthoic acid causes the 6-hydroxy-2-naphthoic acid to be dispersed in pyridine to obtain a second a solution in which 0.2 g of pyridine is added to a mixture consisting of 0.02 mol of 2,5-di-n-butyl hydroquinone and 0.02 mol of terephthalic acid to dissolve and disperse the mixture in pyridine to obtain a third Solution.

The above first solution was added to the first composition, and stirred at room temperature for 10 minutes, and then placed under a nitrogen atmosphere at 80 ° C for 10 minutes to prepare a second composition.

The suspension was added to the second composition under a nitrogen atmosphere at 80 ° C, and the reaction was continued for 30 minutes after dissolution of 6-hydroxy-2-naphthoic acid to prepare a third composition.

The second solution was added to the third composition for 24 hours under a nitrogen atmosphere at 80 ° C to prepare a fourth composition.

Adding the fourth composition to methanol, the modified liquid crystal polymer is precipitated to form a precipitate, and the precipitate is separated by suction filtration and simultaneously washed with methanol, thereby obtaining the modified liquid crystal high. Molecular polymer.

The resin composition was prepared by dissolving the modified liquid crystal polymer in N-methylpyrrolidone, wherein the resin composition had a viscosity of 1,254 cps, and the resin composition had a solid content of 25%.

Example 2

Compared with Example 1, the difference is that the 4-hydroxybenzoic acid is 0.48 mol 48 g, the 6-hydroxy-2-naphthoic acid is 0.48 mol, and the 2,5-di-n-butyl hydroquinone And the terephthalic acid was 0.04 mol, respectively. The viscosity of the resin composition was 1421 cps, and the solid content of the resin composition was 25%.

Example 3

Compared with Example 1, the difference is that the 4-hydroxybenzoic acid is 0.47 mol, the 6-hydroxy-2-naphthoic acid is 0.47 mol, and the 2,5-di-n-butyl-p-phenylene The phenol and terephthalic acid were respectively 0.06 mol. The viscosity of the resin composition was 1542 cps, and the solid content of the resin composition was 25%.

Example 4

Compared with Example 1, the difference is that the 4-hydroxybenzoic acid is 0.46 mol, the 6-hydroxy-2-naphthoic acid is 0.46 mol, and the 2,5-di-n-butyl-p-phenylene The phenol and terephthalic acid were respectively 0.08 mol. The viscosity of the resin composition was 1624 cps, and the solid content of the resin composition was 25%.

Example 5

Compared with Example 1, the difference is that the 4-hydroxybenzoic acid is 0.45 mol, the 6-hydroxy-2-naphthoic acid is 0.45 mol, and the 2,5-di-n-butyl-p-phenylene The phenol and terephthalic acid were respectively 0.1 mol. The viscosity of the resin composition was 1742 cps, and the solid content of the resin composition was 25%.

Example 6

Compared with Example 1, the difference is that the 2,5-di-n-butyl hydroquinone and terephthalic acid are replaced by hydroquinone and 2,5-di-n-butyl terephthalic acid. The hydroquinone and the 2,5-di-n-butylterephthalic acid were respectively 0.02 mol. The viscosity of the resin composition was 1389 cps, and the solid content of the resin composition was 25%.

Example 7

Compared with Example 2, the difference is that the 2,5-di-n-butyl hydroquinone and terephthalic acid are replaced by hydroquinone and 2,5-di-n-butyl terephthalic acid. The hydroquinone and the 2,5-di-n-butylterephthalic acid were respectively 0.04 mol. The viscosity of the resin composition was 1341 cps, and the solid content of the resin composition was 25%.

Example 8

Compared with Example 3, the difference is that the 2,5-di-n-butyl hydroquinone and terephthalic acid are replaced by hydroquinone and 2,5-di-n-butyl terephthalic acid. The hydroquinone and the 2,5-di-n-butylterephthalic acid were respectively 0.06 mol. The viscosity of the resin composition was 1442 cps, and the solid content of the resin composition was 25%.

Example 9

Compared with Example 4, the difference is that the 2,5-di-n-butyl hydroquinone and terephthalic acid are replaced by hydroquinone and 2,5-di-n-butyl terephthalic acid. The hydroquinone and the 2,5-di-n-butylterephthalic acid were respectively 0.08 mol. The viscosity of the resin composition was 1751 cps, and the solid content of the resin composition was 25%.

Example 10

Compared with Example 5, the difference is that the 2,5-di-n-butyl hydroquinone and terephthalic acid are replaced by hydroquinone and 2,5-di-n-butyl terephthalic acid. The hydroquinone and the 2,5-di-n-butylterephthalic acid were respectively 0.1 mol. The viscosity of the resin composition was 1841 cps, and the solid content of the resin composition was 25%.

The resin compositions prepared in Examples 1 to 10 were respectively applied to one surface of 10 copper foils to form experimental samples 1 to 10, and the experimental samples 1 to 10 were baked at 140 ° C for 30 minutes to make copper foil. The modified liquid crystal polymer on the surface is cross-linked and cured to obtain 10 polymer films of the same thickness, and a VECTRA V400P model manufactured by Nippon Polytechnic Co., Ltd. having the same thickness as the polymer film of Example 1 is obtained. As a comparative example, a liquid crystal polymer film was prepared by pressing a high temperature of 300 to 350 degrees Celsius on a copper foil surface to prepare an experimental sample 11.

The dielectric constant D _k and the dielectric loss D _f of the 10 kinds of polymer films formed in the above Examples 1 to 10 and the liquid crystal polymer film of the comparative example were respectively tested, and the above 11 kinds of experimental samples were subjected to soldering and heat resistance. The solubility test of N-methylpyrrolidone in 11 kinds of polymers such as the modified liquid crystal polymer prepared in Examples 1 to 10 and the liquid crystal polymer corresponding to Comparative Example 1 was tested. The modified liquid crystal polymer prepared in Examples 1 to 10 and 11 kinds of polymers such as the liquid crystal polymer corresponding to Comparative Example 1 were tested for melting point. Refer to the performance test data in Table 1 for the test results. Among them, if the soldering heat resistance test condition is greater than or equal to 320 ° C, 10 sec, the rubber layer does not cause foaming, peeling, etc., the soldering heat resistance test result is "pass", indicating that the circuit board meets the heat resistance requirements.

As can be seen from Table 1, the polymer films of Examples 1 to 10 have a lower dielectric constant D _k and a lower dielectric loss D _f than the liquid crystal polymer film of the comparative example, and have the same Good heat resistance. Further, the modified liquid crystal polymer in Examples 1 to 10 is soluble in N-methylpyrrolidone as compared with the liquid crystal polymer film in which the comparative example is insoluble in N-methylpyrrolidone, that is, the modification The liquid crystal polymer has better film forming properties.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The present invention has been described above, and is not intended to limit the present invention, and any skilled person skilled in the art. The equivalents of the above-described technical contents may be modified or modified to equivalent changes without departing from the technical scope of the present invention, and the technical essence according to the present invention is not deviated from the technical scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments are still within the scope of the technical solutions of the present invention.

In addition, various other changes and modifications may be made in accordance with the technical concept of the present invention, and all such changes and modifications are intended to fall within the scope of the invention.

Claims (9)

A modified liquid crystal polymer, the chemical structure of the modified liquid crystal polymer is or Wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from at least one of a chain alkane group and a chain alkoxy group, and the chain alkoxy group is bonded to the benzene by an oxygen atom The chain alkane group is selected from at least one of -C ₄ H ₉ , -C ₆ H ₁₃ and -C ₈ H ₁₇ , and the chain alkoxy group is selected from -OC ₄ H ₉ , At least one of -OC ₆ H ₁₃ and -OC ₈ H ₁₇ , x, y, z, m, n, r, p, q are natural numbers greater than 1, and the ratio range of x: y: z is (45~ 49): (45~49): (2~10), or the ratio of m:n:r is (45~49): (45~49): (2~10), the modified liquid crystal is high The molecular polymer has a melting point of 220 degrees Celsius to 300 degrees Celsius. A method for preparing a modified liquid crystal high molecular polymer, comprising the steps of: mixing 4-toluenesulfonium chloride, N-methylpyrrolidone and pyridine to form a first composition; to 4-hydroxybenzoic acid, 6- Hydroxy-2-naphthoic acid is separately added with pyridine, so that 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are respectively dissolved and dispersed in pyridine to prepare a first solution and a second solution, and the structural formula is a mixture of a diphenolic compound and terephthalic acid or a hydroquinone and a structural formula Pyridine is added to the mixture of diacid compounds, and the mixture is dissolved and dispersed in pyridine to obtain a third solution, wherein R ₁ , R ₂ , R ₃ and R ₄ are each selected from a chain alkane group and a chain. At least one of the alkoxy groups, and the chain alkoxy group is bonded to the phenyl group by an oxygen atom selected from -C ₄ H ₉ , -C ₆ H ₁₃ And at least one of -C ₈ H ₁₇ , the chain alkoxy group being selected from at least one of -OC ₄ H ₉ , -OC ₆ H ₁₃ and -OC ₈ H ₁₇ ; adding the first solution In the first composition, the mixture is uniformly mixed and then heated to obtain a second composition; under heating, the second solution is added to the second composition to obtain a third composition; And a third composition is added to the third composition to obtain a fourth composition, wherein the chemical composition is dissolved in the fourth composition. or The modified liquid crystal polymer wherein x, y, z, m, n, r, p, q are natural numbers greater than 1, and the ratio of x:y:z ranges from (45 to 49): 45~49): (2~10), or the ratio of m:n:r is (45~49): (45~49): (2~10); adding the fourth composition to methanol or ethanol The modified liquid crystal polymer is precipitated to form a precipitate, which is then separated and cleaned to obtain the modified liquid crystal polymer. The melting point of the modified liquid crystal polymer is 220 degrees Celsius to 300 degrees Celsius. . The method for producing a modified liquid crystal polymer according to claim 2, wherein, in the mixture, a mass ratio of the diphenol compound to the terephthalic acid or the pair The mass ratio of the hydroquinone to the diacid compound was 1:1. The method for producing a modified liquid crystal polymer according to claim 2, wherein a mass ratio of the 4-hydroxybenzoic acid to the 4-toluenesulfonium chloride is 49:0.1. The method for producing a modified liquid crystal polymer according to claim 2, wherein a mass ratio of the 4-hydroxybenzoic acid to the 6-hydroxy-2-naphthoic acid is 1:1. The method for producing a modified liquid crystal polymer according to claim 2, wherein a mass ratio of the 4-hydroxybenzoic acid to the mixture is 45:10 to 49:2. A polymer film obtained by baking and curing a modified liquid crystal polymer comprising the modified material according to claim 1, wherein the polymer film comprises the modified liquid crystal polymer A chemical cross-linking structure formed by a cross-linking reaction between polymers. A method for preparing a polymer film obtained by using the modified liquid crystal polymer as described in claim 1, comprising the steps of: baking and curing a resin composition, the resin combination The method includes the modified liquid crystal polymer and a solvent, and a chemical cross-linking structure formed by a crosslinking reaction between the modified liquid crystal polymer. The method for preparing a polymer film according to claim 8, wherein the baking curing temperature is 130 degrees Celsius to 150 degrees Celsius, and the baking curing time is 20 minutes to 40 minutes.