CN108503866B - Thin film, method for forming the same, and copper foil substrate - Google Patents

Abstract

Translated fromChinese

一种薄膜，包括一聚合物，该聚合物由(a)对羟基苯甲酸；(b)6‑羟基‑2‑萘甲酸；以及(c)支链型单体反应形成，其中(c)支链型单体的结构为：

或上述的组合，R为芳基、杂芳基或环烷基，每一R¹各自独立地为‑OH、‑NH₂或‑COOH；其中(a)对羟基苯甲酸与(b)6‑羟基‑2‑萘甲酸的摩尔比例介于50∶50至90∶10之间；其中(a)对羟基苯甲酸与(b)6‑羟基‑2‑萘甲酸的总和与(c)支链型单体的摩尔比介于100∶0.25至100∶0.5之间。该聚合物的固有粘度介于4dL/g至6dL/g之间。

A film comprising a polymer formed by the reaction of (a) p-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) branched monomers, wherein (c) branched The structure of chain monomer is:

Or a combination of the above, R is an aryl, heteroaryl or cycloalkyl group, each R¹ is independently -OH, -NH₂ or -COOH; wherein (a) p-hydroxybenzoic acid and (b) 6- The molar ratio of hydroxy-2-naphthoic acid is between 50:50 and 90:10; where the sum of (a) p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid and (c) branched chain type The molar ratio of the monomers is between 100:0.25 and 100:0.5. The polymer has an intrinsic viscosity between 4dL/g and 6dL/g.

Description

Film, method for forming the same, and copper foil substrate

Technical Field

The invention relates to a film and a copper foil substrate.

Background

Liquid Crystal Polymer (LCP) films are highly heat resistant, low dielectric constant/low dielectric constant loss, highly dimensionally stable, low moisture absorption, flame retardant, thermoplastic and recyclable, and can be used as secondary flexible sheets in place of thermosetting polyimide films (PI films). The existing LCP film has too large thermal expansion coefficient and can not be matched with copper foil to form a copper foil substrate. In view of the foregoing, there is a need for LCP films with low thermal expansion coefficients for use in copper foil substrates.

Disclosure of Invention

One embodiment of the present invention provides a film comprising a polymer selected from the group consisting of (a) para-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer, wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of the sum of (a) p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) branched monomer is between 100:0.25 and 100: 0.5. The intrinsic viscosity of the polymer is between 4dL/g and 6 dL/g.

The method for forming a thin film provided by an embodiment of the present invention includes: taking (a) p-hydroxybenzoic acid, (b) 6-hydroxy-2-naphthoic acid and (c) branched chain monomer for polymerization reaction; melting the polymer to form a film; and heat treating the film, wherein (c) the branched monomer has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of the sum of (a) p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) branched monomer is between 100:0.25 and 100: 0.5. The intrinsic viscosity of the polymer is between 4dL/g and 6 dL/g.

An embodiment of the present invention provides a copper foil substrate, including: a film; and a copper foil attached to the film, wherein the film comprises a polymer selected from the group consisting of (a) parahydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer, wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of (a) the sum of p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) the branched monomer is between 100:0.25 and 100:0.5, and the polymer has an intrinsic viscosity between 4dL/g and 6 dL/g.

Drawings

FIG. 1 is a graph of storage modulus versus loss modulus for a film in accordance with an embodiment of the present invention.

FIG. 2 is a plot of storage modulus versus loss modulus for various films in accordance with an example of the present invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

One embodiment of the present invention provides a film comprising a polymer selected from the group consisting of (a) para-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer, wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH. In one embodiment, the (c) branched monomer is trimesic acid (TMA). (a) The structure of p-hydroxybenzoic acid is

And (b) 6-hydroxy-2-naphthoic acid has the structure

In one embodiment, the monomers (a), (b) and (c) may be mixed with acetic anhydride and then subjected to acetylation (or amidation if R is¹is-NH₂) And (3) carrying out polymerization reaction. The temperature of the acetylation reaction may be between about 150 ℃ and 180 ℃, the acetylation reaction time may be between about 3 hours and 4 hours, the polymerization reaction temperature may be between about 280 ℃ and 300 ℃, and the polymerization reaction time may be between about 1 hour and 2 hours. If the temperature of the acetylation reaction is too low or the time is too short, the acetylation of the monomer is incomplete and the polymerization reaction cannot proceed. If the temperature of acetylation reaction is too high or the time is too long, the monomer material is cracked and cannot be polymerized. If the polymerization reaction temperature is too low or the polymerization reaction time is too short, the molecular weight of the polymer tends to be too low, and the mechanical strength tends to be insufficient. If the polymerization reaction temperature is too high or the polymerization reaction time is too long, yellowing and cracking phenomena of the polymer are easily caused, and poor color and luster and insufficient mechanical strength are caused.

In one embodiment, the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10. In another embodiment, the molar ratio of (a) para-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between about 60:40 and 80: 20. In yet another embodiment, the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between about 70:30 and 80: 20. If the proportion of (a) p-hydroxybenzoic acid is too low, the polymer tends to have no liquid crystal phase and to have poor mechanical strength. If the proportion of (a) p-hydroxybenzoic acid is too high, the polymer tends to be brittle and to have too high a melting point, and thus cannot be used for processing. The molar ratio of the sum of the above (a) p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to the (c) branched monomer is about 100:0.25 to 100: 0.5. If the proportion of the branched monomer (c) is too low, the melt strength of the polymer tends to be insufficient, and the film-forming processability tends to be poor. When the proportion of the branched monomer (c) is too high, the polymerization reaction tends to be difficult to proceed, the polymerization degree of the material tends to be low, and the mechanical strength tends to be poor.

In one embodiment, the Intrinsic Viscosity (IV) of the polymer is between about 4dL/g and 6 dL/g. If the Intrinsic Viscosity (IV) of the polymer is too low, the polymer tends to be brittle and poor in mechanical strength. If the Intrinsic Viscosity (IV) of the polymer is too high, the polymer tends to have poor flowability and poor processability. On the upper partThe polymer has a coefficient of thermal expansion of about 30 ppm/DEG C to 20 ppm/DEG C, and is a low thermal expansion material. The polymer can be melted into a film, and the melting temperature of the polymer is between 100 ℃ and 160 ℃. In one embodiment, the film thickness is between 30 μm and 100 μm, as desired. In one embodiment, the film may be further heat treated at a temperature of about 250 ℃ to about 300 ℃ for a time period of about 2 hours to about 6 hours. The heat treatment may also be performed by first treating at about 250 ℃ to 280 ℃ for about 2 hours to 3 hours, and then increasing the temperature to about 285 ℃ to 300 ℃ for about 2 hours to 3 hours; or the heat treatment is carried out at the temperature of about 250 ℃ to 280 ℃ for about 2 hours, and then the temperature is raised to 290 ℃ for 2 hours. In one embodiment, the film is heat treated to increase its melting temperature, elongation and breaking strength. For example, the film after heat treatment has a melting temperature of about 310 ℃ to 400 ℃, an elongation of about 13% to 25%, and a breaking strength of about 8kgf/mm²To 10kgf/mm²In the meantime. The melt strength is between about 1.4cN and 1.9 cN. In one embodiment, the film has low thermal expansion, high melt strength, high melt temperature, high elongation and high fracture strength, and thus can be used as a board material for a high frequency flexible printed circuit board (FPC), such as a copper foil substrate.

An embodiment of the present invention provides a copper foil substrate, including: a film; and a copper foil attached to the film, wherein the film comprises a polymer selected from the group consisting of (a) parahydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer, wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) p-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of (a) the sum of p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) the branched monomer is from 100:0.25 to 100:0.5, the polymer has an intrinsic viscosity of 4dL/gTo 6 dL/g.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, several embodiments accompanied with figures are described in detail below:

examples

Comparative example 1

Heating 73 molar parts of (a) p-hydroxybenzoic acid, 27 molar parts of (b) 6-hydroxy-2-naphthoic acid and 120 molar parts of acetic anhydride to 150 ℃ for acetylation reaction for 3.5 hours, vacuumizing and heating to 300 ℃ for polymerization reaction, and introducing nitrogen to extrude the molten reaction product to cold water for cooling and cutting into granules after confirming that the torque of a stirring vane motor reaches 220w to obtain the product. The viscosity (intrinsic viscosity (IV) of the product was measured with an Ostwald viscometer by dissolving the sample in 3, 5-bis-trifluoromethyl phenol (3, 5-bis-trifluoromethyl phenol) (in a 30 ℃ incubator), providing slight agitation by means of a stirring motor (115V.50/60CY, 1.2A, 1550RPM) and measured with an Ostwald viscometer, and the melting temperature (Tm) of the product was measured with a Differential Scanning Calorimeter (DSC) as shown in Table 1.

After drying the above product under vacuum by heating to 140 ℃ for 8 hours, it was melted to form a film having a thickness of about 70 μm, and the film forming properties were confirmed as shown in Table 2. The thermal expansion properties of the films were measured with a thermomechanical analyzer (instrument model DMA-7e, manufacturer source Perkinelmer) as shown in Table 2. The Elongation (Elongation) and breaking strength of the film were measured by a universal material tester (Instrument model 4505, INSTRON from manufacturer) as shown in Table 3. The melt strength of the film was measured with a polymer melt strength meter (model Rheotens, from Gottfert, manufacturer) as shown in Table 3.

In addition, the material rheology of the films was measured with a polymer extensometer and dynamic viscoelastometer (equipment model MARS III, manufacturer's Thermo), as shown in FIG. 1. As shown in FIG. 1, the Loss modulus (G ') of the film is greater than the Storage modulus (G'), the rheology is liquid, and the melt strength is low, so that the film processability is poor.

In addition, for the above-mentioned thin filmThe film was subjected to heat treatment (after heat treatment at 280 ℃ for 2 hours, the temperature was raised to 290 ℃ for 2 hours), and the T of the heat-treated film was measured_mAs shown in table 1.

Example 1

Similar to comparative example 1, the difference is that the monomer of example 1 further contains 0.25 mol% of trimesic acid (TMA) in addition to p-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA). The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3.

In addition, the material rheology of the films was measured with a polymer extensometer and dynamic viscoelastometer (equipment model MARS III, manufacturer's Thermo), as shown in FIG. 2. As shown in FIGS. 1 and 2, the film of example 1 has a lower Loss modulus (Loss modulus, G ') and Storage modulus (G') than the film of comparative example 1, a rheological behavior of visco-elastic behavior (visco-elastic behavior), and a higher melt strength, which facilitates film processing.

Example 2

Example 2 is similar to comparative example 1, with the difference that the monomer of example 2 further comprises 0.5 mol% TMA, in addition to HBA and HNA. The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3.

In addition, in addition to the measurement of Tm of the film after the heat treatment, the elongation (14.93%, elongation increased by 37.6% as compared with the elongation of the film before the heat treatment) and the breaking strength (8.85 kgf/mm) of the film after the heat treatment were also measured²29% greater than the film break strength before heat treatment).

Comparative example 2

Comparative example 2 is similar to comparative example 1, except that the monomer of comparative example 2 further contains 0.75 mol% of TMA in addition to HBA and HNA. The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3.

In addition, the material rheology of the films was measured with a polymer extensometer and dynamic viscoelastometer (equipment model MARS III, manufacturer's Thermo), as shown in FIG. 2. As shown in FIGS. 1 and 2, the Loss modulus (G ') and Storage modulus (G') of the film of comparative example 2 are similar to those of comparative example 1, the rheology is liquid, and the melt strength is too low to be measured, so that the film processability is poor.

Comparative example 3

Comparative example 3 is similar to comparative example 1, except that the monomer of comparative example 3 further contains 1 mol% of TMA in addition to HBA and HNA. The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3. However, the melt strength of the film of this example was too low to be measured, and thus the film processability was poor.

Comparative example 4

Comparative example 4 is similar to comparative example 1, except that the monomer of comparative example 4 further contains 3 mol% of TMA in addition to HBA and HNA. The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3. However, the product of this example was poor in film forming properties, so no other film properties were measured.

Comparative example 5

Comparative example 5 is similar to comparative example 1, except that the monomer of comparative example 5 further contains 5 mol% of TMA in addition to HBA and HNA. The measurement methods for the parameters and properties of the other reactions were similar to those of comparative example 1. The measurement results are shown in tables 1 to 3. However, the product of this example was poor in film forming properties, so no other film properties were measured.

As can be seen from Table 3, the film containing 0.25 mol% to 0.5 mol% TMA in the monomer had high elongation, breaking strength and melt strength. In addition, the melting temperature, the elongation and the breaking strength of the film after heat treatment are improved, and the film processing is also facilitated.

TABLE 1

TABLE 2

TABLE 3

In table 2, the excellent film forming property is defined as high continuous bending toughness after the material is formed into a film, the excellent film forming property is defined as bending after the material is formed into a film, and the poor film forming property is defined as non-bending and brittle after the material is formed into a film. It is notable that some films have good film forming properties, but their melt strength is insufficient to result in poor film processability.

Example 3

After the film of example 1 was laminated with a copper foil (commercial model number HA and JX from Taiwan Riyue metals Co., Ltd.) of Taiwan Riyue metals Co., Ltd., a solder-resistant strength test (340 ℃ C., 10 seconds) was carried out, and no plate burst was observed.

Comparative example 6

The film of comparative example 2 was laminated with a copper foil (commercial model number HA and JX from Taiwan-Riyule metals Co., Ltd.) available from Taiwan-Riyue metals Co., Ltd. to obtain a copper foil substrate, and then a solder-resistance strength test (340 ℃ C., 10 seconds) was carried out to produce a knock-out plate.

Comparative example 7

After laminating a commercially available film A950 with a copper foil (commercial model HA and JX from Taiwan Riyue metals Co., Ltd.) available from Taiwan Riyue metals Co., Ltd., a solder-resistance strength test (340 ℃ C., 10 seconds) was carried out to produce a knock-out plate.

From the above, the film of example 1 having a high elongation, a high breaking strength and a low thermal expansion coefficient is suitable for a copper foil substrate.

Example 4

The polymers of comparative example 1, example 1 and example 2 were melted into films. The three films had a thickness of 50 μm and a length of 100 mm. The dielectric constant and the dielectric loss of the above film were measured at a measuring frequency of 10GHz (measurement standard IPC. TM. -6502.5.5.13).

LCP films CT-Z and CT-F were obtained from Kuraray. The films CT-Z and CT-F have a thickness of 0.5mm and a length of 100 mm. The dielectric constant and the dielectric loss were measured at a measurement frequency of 10GHz, respectively (measurement standard IPC. TM. -6502.5.5.13).

Further, the film obtained by melting the polymer of example 2 was subjected to an additional heat treatment (after heat treatment at 280 ℃ for 2 hours, the temperature was raised to 290 ℃ for 2 hours), and the dielectric constant and the dielectric loss of the heat-treated film were measured at a measurement frequency of 10GHz (measurement standard IPC. TM. -6502.5.5.13). The properties of the above film are shown in table 4.

TABLE 4

As is clear from Table 4, the addition of a proper amount of TMA did not affect the dielectric constant of the film and the dielectric loss was reduced. In other words, the LCP film with TMA monomer introduced therein has excellent signal transmission rate and less signal loss, and can be applied to a Flexible Copper Clad Laminate (FCCL) for 4G/5G high frequency transmission.

Commercially available films CT-Z and CT-F and a home-made LCP film (comparative example 1, example 2 and example 2 further heat treated) were plasma treated and laminated to a copper foil HA. The pressing parameters are as follows: pressing was carried out at a pressing temperature shown in Table 5 for 30 minutes under a pressing pressure of 40Kgf/cm². The finished product has good appearance smoothness and no bubbles. The adhesion strength between the copper foil and the film of the above-mentioned finished product was measured, and its measurement standard was IPC-TM-6502.4.8.

TABLE 5

As is clear from Table 5, the polymer film of the present invention to which an appropriate amount of TMA was added significantly increased the adhesive strength between the film and the copper foil, whereas the polymer film without TMA (comparative example 1) had an adhesive strength between the film and the copper foil similar to that between a commercially available film and a copper foil.

On the other hand, a Flexible Copper Clad Laminate (FCCL) formed by laminating the polymer film and the copper foil of examples 1 and 2 was laminated with a dry film resist at 100 ℃. Then, the dry film photoresist is exposed to 1% Na₂CO₃After developing the dry film photoresist in the aqueous solution, the copper circuit with the line width of 50 μm is etched at the etching temperature of 60 ℃, and no residual copper is left at the etching position. After the above-mentioned photolithography and etching process, the flexible copper foil substrate material (FCCL) has no abnormality (such as the delamination of copper foil and polymer film).

It should be understood that the above-mentioned embodiments are only exemplary of the present invention, and are not intended to limit the present invention, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (14)

1. A film, comprising:

a polymer comprising (a) p-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer,

wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) para-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of (a) the sum of p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) the branched monomer is between 100:0.25 and 100:0.5, and the intrinsic viscosity of the polymer is between 4dL/g and 6 dL/g.

2. The film of claim 1, wherein the molar ratio of (a) parahydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 60:40 and 80: 20.

3. The film of claim 1, wherein the molar ratio of (a) parahydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 70:30 and 80: 20.

4. The film of claim 1 wherein (c) the branched monomer is trimesic acid.

5. The film of claim 1 having a melt strength between 1.4cN and 1.9 cN.

6. The film of claim 1 having an elongation of between 13% and 25%.

7. The film of claim 1 having a breaking strength of between 8kgf/mm²To 10kgf/mm²In the meantime.

8. A method of forming a thin film, comprising:

taking (a) p-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) polymerizing the branched monomer;

melting the polymer to form a film; and

the thin film is subjected to a heat treatment,

wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) para-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of (a) the sum of p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) branched monomer is between 100:0.25 and 100:0.5, and wherein the polymer has an intrinsic viscosity between 4dL/g and 6 dL/g.

9. The method of claim 8, wherein the polymerization further comprises adding an anhydride compound having an anhydride number in a molar ratio of (a) p-hydroxybenzoic acid to the sum of (b) 6-hydroxy-2-naphthoic acid of 80:100 to 120: 100.

10. The method of claim 8, wherein the polymerization temperature is between 280 ℃ and 330 ℃.

11. The method of claim 8, wherein the melting temperature is between 100 ℃ and 160 ℃.

12. The method of claim 8, wherein the heat treatment is performed at a temperature of 250 ℃ to 300 ℃.

13. A copper foil substrate comprising:

a film; and

a copper foil, which is attached to the film,

wherein the film comprises: a polymer comprising (a) p-hydroxybenzoic acid; (b) 6-hydroxy-2-naphthoic acid; and (c) a branched monomer,

wherein the branched monomer of (c) has the structure:

or combinations of the above, R is aryl, heteroaryl, or cycloalkyl, each R is¹Each independently is-OH, -NH₂or-COOH; wherein the molar ratio of (a) para-hydroxybenzoic acid to (b) 6-hydroxy-2-naphthoic acid is between 50:50 and 90: 10; wherein the molar ratio of (a) the sum of p-hydroxybenzoic acid and (b) 6-hydroxy-2-naphthoic acid to (c) the branched monomer is between 100:0.25 and 100:0.5, and the intrinsic viscosity of the polymer is between 4dL/g and 6 dL/g.

14. The copper foil substrate of claim 13, wherein (c) the branched monomer is trimesic acid.

Images