Manufacturing method of metal-clad laminates

Abstract

In the manufacture of a metal-clad laminate using a melt-extruded thermoplastic liquid crystal polymer resin, the present invention provides a metal-clad laminate in which the thickness tolerance of the thermoplastic liquid crystal polymer layer is reduced. [Solution] A method for manufacturing a metal-clad laminate comprising a thermoplastic liquid crystal polymer layer and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, wherein the pair of pressure rolls consists of a first roll and a second roll, both having metal surfaces, and comprises at least the steps of: supplying metal foil to the first roll and / or the second roll; supplying molten-extruded thermoplastic liquid crystal polymer resin between the first roll and the second roll; and lamination steps of passing the supplied metal foil and thermoplastic liquid crystal polymer resin between the pair of pressure rolls to form a thermoplastic liquid crystal polymer layer, wherein the first roll and / or the second roll are metal elastic rolls.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a metal-clad laminate composed of a thermoplastic liquid crystal polymer layer containing a polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer.

Background Art

[0002] Thermoplastic liquid crystal polymer films are useful as base films for circuit boards due to their excellent mechanical strength, electrical properties, etc. In recent years, they are widely used as flexible circuit board materials in the fields of electric / electronic devices and automotive parts. Among them, miniaturization and high density of circuit boards are desired, and flexible circuit board materials need to be thinned, and the thermoplastic liquid crystal polymer films of the materials are required to have no film thickness unevenness.

[0003] Patent Document 1 describes that when manufacturing a laminate composed of a layer made of a thermoplastic resin having a specific bending temperature and a metal foil, the melt-extruded thermoplastic resin and the heated metal foil are heat-bonded using a pair of pressure rolls, and a liquid crystal polymer is disclosed as the thermoplastic resin. In Patent Document 2, a method of laminating a thermoplastic liquid crystal polymer film and a metal sheet with a metal elastic roll is also being studied.

Prior Art Documents

Patent Documents

[0006] The present invention aims to provide a method for manufacturing metal-clad laminates in which a melt-extruded thermoplastic liquid crystal polymer resin is pressed onto a metal foil, resulting in a metal-clad laminate with a small film thickness tolerance and stable performance over a long period of time even under high-temperature conditions. [Means for solving the problem]

[0007] The inventors of the present invention, after diligent research to achieve the above objective, discovered that by using a metal elastic roll as the pressing roll in the production of a metal-clad laminate in which a melt-extruded thermoplastic liquid crystal polymer resin is pressed onto a metal foil, it is possible to produce a metal-clad laminate with a small tolerance for the thickness of the thermoplastic liquid crystal polymer layer and to produce a stable metal-clad laminate over a long period of time even under high-temperature conditions, thus completing the present invention.

[0008] In other words, the present invention may be configured in the following embodiments. [Aspect 1] A method for manufacturing a metal-clad laminate using a pair of pressure rolls, comprising a thermoplastic liquid crystal polymer layer containing a polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, A method for manufacturing a metal-clad laminate, wherein the pair of compression rolls consist of a first roll and a second roll, both having metal surfaces, and the method comprises at least the steps of: supplying metal foil to the first roll and / or the second roll; supplying molten-extruded thermoplastic liquid crystal polymer resin between the first roll and the second roll; and lamination, wherein the supplied metal foil and thermoplastic liquid crystal polymer resin are passed between the pair of compression rolls to form a thermoplastic liquid crystal polymer layer on the metal foil, and the first roll and / or the second roll are metal elastic rolls.

[0009] [Aspect 2] A method for manufacturing a metal-clad laminate, wherein one of a pair of crimping rolls is a metal heating roll and the other roll is a metal elastic roll.

[0010] [Aspect 3] A method for manufacturing a metal-clad laminate, according to embodiment 1 or 2, wherein the pressure between a pair of crimping rolls is 0.1 to 30 kg / mm ​​(preferably 0.1 to 20 kg / mm, more preferably 0.5 to 10 kg / mm, and even more preferably 1 to 5 kg / mm) in terms of linear pressure.

[0011] [Aspect 4] A method for manufacturing a metal-clad laminate according to any one of embodiments 1 to 3, comprising the step of cooling the surface of the metal elastic roll.

[0012] [Aspect 5] A method for manufacturing a metal-clad laminate according to any one of embodiments 1 to 4, wherein the thickness of the metal foil is 6 μm or more and 35 μm or less.

[0013] [Aspect 6] The manufacturing method according to any one of Aspects 1 to 5, wherein the thickness of the thermoplastic liquid crystal polymer layer is 5 μm or more and 300 μm or less, for manufacturing a metal-clad laminate.

[0014] [Aspect 7] The manufacturing method according to any one of Aspects 1 to 6, further comprising a heating step of heating and drying the metal foil before supplying the metal foil to a pair of pressure rolls, for manufacturing a metal-clad laminate.

[0015] [Aspect 8] The manufacturing method according to any one of Aspects 1 to 7, wherein the first roll is a metal roll, the second roll is a metal elastic roll, when the metal roll is MR, the metal elastic roll is MER, the metal foil is M, and the thermoplastic liquid crystal polymer resin is LCP, the arrangement of MR, MER, M, LCP is as follows: MR / M / LCP / MER MR / LCP / M / MER, or MR / M / LCP / M / MER The supply step of the thermoplastic liquid crystal polymer resin is performed so as to be in this configuration, for manufacturing a metal-clad laminate.

[0016] [Aspect 9] The manufacturing method according to any one of Aspects 1 to 7, wherein the first roll is a metal elastic roll, the second roll is a metal roll, when the metal elastic roll is MER, the metal roll is MR, the metal foil is M, and the thermoplastic liquid crystal polymer resin is LCP, the arrangement of MER, MR, M, LCP is as follows: MER / M / LCP / MR MER / LCP / M / MR, or MER / M / LCP / M / MR The supply step of the thermoplastic liquid crystal polymer resin is performed so as to be in this configuration, for manufacturing a metal-clad laminate. [Advantages of the Invention]

[0017] According to the present invention, a thermoplastic liquid crystal polymer resin that has been melt-extruded and a metal foil are laminated while being nipped by a pair of pressure rolls using at least one metal elastic roll. By using a metal roll on the other side, even if a heat crown phenomenon occurs in the metal roll, the metal elastic roll follows, thereby relaxing the gap change. Therefore, it is possible to reduce the film thickness tolerance of the thermoplastic liquid crystal polymer layer, and it is possible to stably manufacture a metal-clad laminate over a long period even in the molding of a high-temperature molten resin.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram for explaining an apparatus used in a method for manufacturing a single-sided metal-clad laminate according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram for explaining an apparatus used in a method for manufacturing a double-sided metal-clad laminate according to a second embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0019] <Method for Manufacturing a Metal-Clad Laminate> The method for manufacturing a metal-clad laminate of the present invention is a method for manufacturing a metal-clad laminate composed of a thermoplastic liquid crystal polymer layer containing a polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer using a pair of pressure rolls. The pair of pressure rolls are both composed of a first roll and a second roll whose surfaces are formed of metal, and while supplying a metal foil to the first roll and / or the second roll, a molten-extruded thermoplastic liquid crystal polymer resin is supplied between the first roll and the second roll. And a lamination step of forming a thermoplastic liquid crystal polymer layer by passing the supplied thermoplastic liquid crystal polymer resin between the pair of pressure rolls. The method for manufacturing a metal-clad laminate, wherein the first roll and / or the second roll is a metal elastic roll.

[0020] In the above method, when the thermoplastic liquid crystal polymer resin is supplied, metal foil is also supplied between the first roll and the second roll. Therefore, supplying thermoplastic liquid crystal polymer resin between the first roll and the second roll means supplying the thermoplastic liquid crystal polymer resin between the metal foil on the first roll and the second roll, between the first roll and the metal foil on the second roll, or between the metal foil on the first roll and the metal foil on the second roll. This includes not only cases where the resin is directly extruded toward the gap between the pair of compression rolls, but also cases where the resin extruded onto the surface of the first roll or the second roll, or onto the metal foil on the roll, flows into the gap along the outer circumference of the roll. It also includes cases where a release sheet or a shaping sheet is placed on the outer circumference of the first roll or the second roll, and the resin is supplied between the pair of compression rolls while sandwiched between these sheets and the metal foil.

[0021] The above method may include a step of winding the formed metal-clad laminate onto a winding roll positioned horizontally away from the crimping roll (horizontally, the rotation axis is positioned horizontally away from the gap between the pair of rolls). In this case, the crimping roll positioned horizontally away from the winding roll may be referred to as the first roll, and the crimping roll positioned closer to the winding roll may be referred to as the second roll.

[0022] (Thermoplastic liquid crystal polymer resin) The thermoplastic liquid crystal polymer resin used in the manufacturing method of the present invention includes a thermoplastic liquid crystal polymer. The thermoplastic liquid crystal polymer is composed of a melt-mold liquid crystalline polymer (or a polymer capable of forming an optically anisotropic molten phase), and its chemical composition is not particularly limited as long as it is a melt-mold liquid crystalline polymer. Examples include thermoplastic liquid crystal polyester, or thermoplastic liquid crystal polyesteramide in which an amide bond is introduced thereto.

[0023] Furthermore, the thermoplastic liquid crystal polymer may be a polymer in which an aromatic polyester or aromatic polyesteramide is further modified by introducing isocyanate-derived bonds such as imide bonds, carbonate bonds, carbodiimide bonds, or isocyanurate bonds.

[0024] Specific examples of thermoplastic liquid crystal polymers used in the present invention include known thermoplastic liquid crystal polyesters and thermoplastic liquid crystal polyesteramides derived from compounds classified as (1) to (4) below and their derivatives. However, it goes without saying that there is an appropriate range for the combination of various raw material compounds in order to form a polymer that can form an optically anisotropic molten phase.

[0025] (1) Aromatic or aliphatic diols (see Table 1 for representative examples) [Table 1]

[0026] (2) Aromatic or aliphatic dicarboxylic acids (see Table 2 for representative examples) [Table 2]

[0027] (3) Aromatic hydroxycarboxylic acids (see Table 3 for representative examples) [Table 3]

[0028] (4) Aromatic diamines, aromatic hydroxyamines, or aromatic aminocarboxylic acids (see Table 4 for representative examples) [Table 4]

[0029] Typical examples of thermoplastic liquid crystal polymers obtained from these raw material compounds include copolymers having repeating units, as shown in Tables 5 and 6.

[0030] [Table 5] [Table 6]

[0031] Of these copolymers, copolymers containing p-hydroxybenzoic acid and / or 6-hydroxy-2-naphthoic acid as at least a repeating unit are preferred, and in particular, (i) copolymers containing repeating units of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, or (ii) copolymers containing repeating units of at least one aromatic hydroxycarboxylic acid selected from the group consisting of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, at least one aromatic diol and / or aromatic hydroxyamine, and at least one aromatic dicarboxylic acid are preferred.

[0032] For example, in copolymer (i), if the thermoplastic liquid crystal polymer contains repeating units of at least p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, the molar ratio (A) / (B) of p-hydroxybenzoic acid in repeating unit (A) to 6-hydroxy-2-naphthoic acid in repeating unit (B) is preferably about 10 / 90 to 90 / 10 in the thermoplastic liquid crystal polymer, more preferably about 15 / 85 to 85 / 15, and even more preferably about 20 / 80 to 80 / 20.

[0033] In addition, in the case of copolymer (i), in addition to the repeating units of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, repeating units composed of aromatic diols or aromatic dicarboxylic acids (e.g., terephthalic acid) may be included from the viewpoint of adjusting the molecular weight, etc.

[0034] Furthermore, in the case of copolymer (ii), at least one aromatic hydroxycarboxylic acid (C) selected from the group consisting of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, at least one aromatic diol (D) selected from the group consisting of 4,4'-dihydroxybiphenyl, hydroquinone, phenylhydroquinone, and 4,4'-dihydroxydiphenyl ether, and at least one aromatic dicarb selected from the group consisting of terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid The molar ratio of acid (E) to each repeating unit in the thermoplastic liquid crystal polymer may be approximately (C):(D):(E) = (30~80):(35~10):(35~10), more preferably (C):(D):(E) = (35~75):(32.5~12.5):(32.5~12.5), and even more preferably (C):(D):(E) = (40~70):(30~15):(30~15).

[0035] Furthermore, the molar ratio of repeating units derived from 6-hydroxy-2-naphthoic acid among the aromatic hydroxycarboxylic acid (C) may be, for example, 85 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more. The molar ratio of repeating units derived from 2,6-naphthalenedicarboxylic acid among the aromatic dicarboxylic acid (E) may be, for example, 85 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more.

[0036] Furthermore, the aromatic diol (D) may be repeating units (D1) and (D2) derived from two different aromatic diols selected from the group consisting of hydroquinone, 4,4'-dihydroxybiphenyl, phenylhydroquinone, and 4,4'-dihydroxydiphenyl ether, in which case the molar ratio of the two aromatic diols may be (D1) / (D2) = 23 / 77 to 77 / 23, more preferably 25 / 75 to 75 / 25, and even more preferably 30 / 70 to 70 / 30.

[0037] Furthermore, the molar ratio of repeating structural units derived from aromatic diols to repeating structural units derived from aromatic dicarboxylic acids is preferably (D) / (E) = 95 / 100 to 100 / 95. If the ratio deviates from this range, the degree of polymerization does not increase and the mechanical strength tends to decrease.

[0038] Furthermore, the ability to form an optically anisotropic molten phase as referred to in this invention can be determined, for example, by placing the sample on a hot stage, heating it in a nitrogen atmosphere, and observing the transmitted light of the sample.

[0039] The melting point (Tm0) of the thermoplastic liquid crystal polymer resin is preferably in the range of 200 to 380°C, more preferably in the range of 260 to 370°C, even more preferably in the range of 300 to 360°C, even more preferably in the range of 305 to 355°C, and particularly preferably in the range of 310 to 350°C. The melting point of the thermoplastic liquid crystal polymer resin can be obtained by observing the thermal behavior of the thermoplastic liquid crystal polymer resin sample using a differential scanning calorimeter. Specifically, the melting point (Tm0) of the thermoplastic liquid crystal polymer resin can be determined by heating the thermoplastic liquid crystal polymer resin sample from room temperature (e.g., 25°C) at a rate of 10°C / min until it is completely melted at 400°C, then cooling the molten material to 50°C at a rate of 10°C / min, and then heating it again at a rate of 10°C / min, at which point the position of the endothermic peak that appears is taken.

[0040] Furthermore, from the viewpoint of melt moldability, the thermoplastic liquid crystal polymer resin may have, for example, a melt viscosity of 30 to 120 Pa·s at a shear rate of 1000 / s at (Tm0+20)°C, and preferably a melt viscosity of 50 to 100 Pa·s.

[0041] The thermoplastic liquid crystal polymer resin used in the present invention may contain thermoplastic polymers such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, polyether ether ketone, and fluororesin, as well as various additives, to the extent that the effects of the present invention are not impaired. Furthermore, it may contain fillers such as organic fillers and inorganic fillers as needed. Therefore, the thermoplastic liquid crystal polymer resin of the present invention consists of a thermoplastic liquid crystal polymer composition mainly comprising a thermoplastic liquid crystal polymer, and containing one or more of these different polymers, additives, and fillers.

[0042] The thermoplastic liquid crystal polymer resin may contain 50% by weight or more of thermoplastic liquid crystal polymer, preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, and even more preferably 98% by weight or more.

[0043] (Metal foil) The metal foil used in the manufacturing method of the present invention is not particularly limited, and may be, for example, a metal foil formed from gold, silver, copper, iron, nickel, aluminum, or alloys thereof. From the viewpoint of conductivity, handling, and cost, copper foil or stainless steel foil is preferred. As for the copper foil, rolled copper foil produced by the rolling method or electrolytic copper foil produced by the electrolytic method can be used.

[0044] The thickness of the metal foil can be set as appropriate as needed, for example, it may be 1 to 100 μm, preferably 5 to 50 μm, and more preferably 6 to 35 μm.

[0045] Metal foils that have undergone surface roughening treatment may be used. From the viewpoint of improving high-frequency characteristics, the roughened surface (matte surface, etc.) of the metal foil preferably has an arithmetic mean roughness Ra of 0.02 to 0.50 μm, more preferably 0.05 to 0.30 μm, and even more preferably 0.10 to 0.20 μm. The arithmetic mean roughness Ra is measured in accordance with JIS B 0601:2001.

[0046] (Metal foil heating process) The manufacturing method of the present invention may include a heating step of heating and drying the metal foil before it is supplied to the first roll and / or the second roll. Heating and drying the metal foil removes moisture from the metal foil and reduces the temperature difference with the melt-extruded thermoplastic liquid crystal polymer resin.

[0047] There are no particular restrictions on the method of heating and drying, and known methods can be used. For example, heating may be performed by providing a heating roll separately from the pair of crimping rolls, or by bringing the metal foil into contact with the outer circumferential surfaces of the first roll and / or the second roll. In this case, the starting point at which the metal foil comes into contact with the outer circumferential surface of the roll (the starting point in the cross-section of the roll) can be appropriately set according to the size of the roll and the rotation speed of the roll, and the metal foil may be conveyed from a predetermined starting point to the crimping position while keeping it in contact with the outer circumferential surface of the roll.

[0048] The temperature in the heating process may be determined based on the temperature of the crimping roll. For example, if the temperature of the crimping roll is T°C, the temperature in the heating process may be, for example, T-10°C or higher, or T-5°C or higher, and is preferably lower than the crimping temperature, with an upper limit of less than T°C. Alternatively, when the metal foil is heated by contacting it with the outer circumferential surface of the first roll and / or the second roll, the temperature in the heating process is the same as the temperature of the crimping roll, T°C.

[0049] In the heating process, the heating time can be set appropriately depending on the heating method.

[0050] (Metal foil supply process) The present invention relates to a method for manufacturing a metal-clad laminate comprising a thermoplastic liquid crystal polymer layer and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, wherein the pair of pressure rolls consists of a first roll and a second roll, both of which have metal surfaces, and the method comprises at least a step of supplying the metal foil to the first roll and / or the second roll.

[0051] In the manufacturing method of the present invention, the metal foil supplied to the first roll and / or the second roll may be one sheet or two sheets. For example, if there is one sheet of metal foil, it is supplied to either the first roll or the second roll, and if there are two sheets of metal foil, they are supplied to the first roll and the second roll respectively. Supplying metal foil to a roll means conveying the metal foil onto the outer circumference of the roll, which is usually done by taking the metal foil (or metal-clad laminate after the start of molten resin supply) downstream of the crimping roll (for example, by winding it up with a winding roll).

[0052] In the manufacturing method of the present invention, when the metal foil is supplied to the first roll and / or the second roll, a protective material may be supplied simultaneously to the outside (roll side) of the metal foil. Alternatively, the protective material may be peeled off after the lamination process described later.

[0053] Examples of protective materials include heat-resistant resin sheets such as polyimide film, aramid film, and Teflon® film, which can be easily peeled off the metal-clad laminate after the lamination process and are heat-resistant; heat-resistant composite sheets (for example, composite sheets made up of multiple heat-resistant resin sheets); and heat-resistant nonwoven fabrics made of heat-resistant fibers (for example, heat-resistant resin fibers). These protective materials may be used individually or in combination of two or more types. The thickness of the protective material can be set as appropriate as needed, for example, it may be about 10 to 300 μm, preferably in the range of 20 to 150 μm, and more preferably in the range of 25 to 100 μm.

[0054] Furthermore, to improve the ability to peel off the metal-clad laminate after the lamination process, a release treatment may be applied to one or both sides of the protective material. Examples of release treatment methods include applying a heat-resistant release resin coating, such as silicone resin or fluororesin, to at least one side of the protective material.

[0055] (Supplying process for thermoplastic liquid crystal polymer resin) The present invention relates to a method for manufacturing a metal-clad laminate comprising a thermoplastic liquid crystal polymer layer and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, wherein the pair of compression rolls consists of a first roll and a second roll, both of which have metal surfaces, and the method comprises at least a step of supplying molten-extruded thermoplastic liquid crystal polymer resin between the first roll and the second roll.

[0056] For example, if the first roll is a metal roll and the second roll is a metal elastic roll, and the metal roll is denoted as MR, the metal elastic roll as MER, the metal foil as M, and the thermoplastic liquid crystal polymer resin as LCP, then the arrangement of MR, MER, M, and LCP is as follows: MR / M / LCP / MER MR / LCP / M / MER, or MR / M / LCP / M / MER The supply process for the thermoplastic liquid crystal polymer resin may be carried out in such a manner.

[0057] Alternatively, if the first roll is a metal elastic roll and the second roll is a metal roll, and the metal elastic roll is designated as MER, the metal roll as MR, the metal foil as M, and the thermoplastic liquid crystal polymer resin as LCP, then the arrangement of MER, MR, M, and LCP is as follows: MER / M / LCP / MR MER / LCP / M / MR, or MER / M / LCP / M / MR The supply process for the thermoplastic liquid crystal polymer resin may be carried out in such a manner.

[0058] In the manufacturing method of the present invention, the method of melt-extruding the thermoplastic liquid crystal polymer resin is not particularly limited, and any extruder can be used as long as the orientation of the rigid rod-shaped molecules of the thermoplastic liquid crystal polymer can be controlled, such as a single-screw extruder, twin-screw extruder, or multi-screw extruder.

[0059] It is preferable to then supply the molten resin obtained by a melting means such as an extruder to a die using a gear pump. Using a gear pump reduces fluctuations in the discharge volume in the extruder, improves the stability of the supply speed (supply volume / time), and improves the stability of the thickness of the thermoplastic liquid crystal polymer layer. The molten resin supplied at a stable supply speed by the gear pump, or the molten resin supplied directly from the extruder, is supplied to the die, for example, through a tubular flow path, and discharged from the die in the form of a film.

[0060] As for the die, conventionally known dies can be used to form the molten resin that is extruded in a film-like manner, and dies of various structures can be used. In the manufacturing method of the present invention, it is preferable to use a T-die to supply the thermoplastic liquid crystal polymer resin that has been molten extruded to the first roll.

[0061] The die temperature for melt extrusion is not particularly limited as long as it is above the flow start temperature of the thermoplastic liquid crystal polymer resin, but it is set considering the adhesion to the metal foil and the extrusion pressure of the extruder. For example, it is preferable to set the die temperature and extrusion pressure to a range of (Tm0-15)°C to (Tm0+50)°C relative to the melting point (Tm0) of the thermoplastic liquid crystal polymer resin, and to apply a pressure of about 1 to 15 kg / mm. In this invention, since both the first roll and the second roll constituting the pair of crimping rolls have metal surfaces, long-term stable manufacturing is possible even when molding molten resin discharged from a high-temperature T-die as described above.

[0062] Furthermore, stretching may be performed as needed when melt-extruding the thermoplastic liquid crystal polymer resin. The stretching method itself is well known, and either biaxial stretching or uniaxial stretching may be used, but biaxial stretching is preferred because it is easier to control the degree of molecular orientation.

[0063] For example, in T-die extrusion molding, it is possible to stretch the thermoplastic liquid crystal polymer resin extruded from the T-die faster than the extrusion rate by adjusting the winding speed of the metal-clad laminate. The thermoplastic liquid crystal polymer layer may be stretched not only in the MD direction but also simultaneously in both the MD and TD directions to form a film, or the thermoplastic liquid crystal polymer resin extruded from the T-die may be stretched in the MD direction first, and then stretched in the TD direction by roll pressure when laminating with metal foil using a pressure roll.

[0064] (Lamination process) The present invention relates to a method for manufacturing a metal-clad laminate comprising a thermoplastic liquid crystal polymer layer and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, using a pair of pressure rolls, comprising at least a lamination step of passing a thermoplastic liquid crystal polymer resin between the pair of pressure rolls to form the thermoplastic liquid crystal polymer layer.

[0065] The first roll and / or second roll constituting the pair of compression rolls are metallic elastic rolls. Preferably, one roll of the pair of compression rolls is a metal heating roll and the other roll is a metallic elastic roll. A metallic elastic roll is a roll composed of an elastic body roll and a metal surface layer formed around it. An elastic body roll is a roll that has the characteristic of being more elastically deformable than a metal roll. The material constituting the elastic body roll is not particularly limited to organic or inorganic materials, but examples of organic materials include preferably rubber rolls, more preferably heat-resistant rubber rolls. Examples of inorganic materials include inorganic nonwoven fabric rolls. Alternatively, a hollow roll made of metal or heat-resistant resin filled with air or an inert gas at a constant pressure may be used. In that case, a hollow roll with a metal layer as its outer shell filled with air or an inert gas may be used as a metallic elastic roll. Alternatively, a roll comprising an axial roll and a thin metal film covering the outer surface of the axial roll, with a fluid sealed between the axial roll and the thin metal film, may be used. The thin metal film is fixed at both ends of the axial roll, and the fluid sealed between the thin metal film and the axial roll can be, for example, water or oil. By controlling the temperature of this fluid, it becomes possible to control the temperature of the metal elastic roll.

[0066] The hardness of the heat-resistant rubber roll used in metal elastic rolls is not particularly limited as long as it is suitable for the molding temperature, but it may be between 60 and 250 degrees, more preferably between 70 and 200 degrees, and more preferably between 80 and 150 degrees. The hardness referred to is the hardness measured according to JIS K 6253-3:2012.

[0067] The thickness of the metal surface layer formed around the elastic roll may be, for example, 100 to 1000 μm, preferably 150 to 800 μm, and more preferably 200 to 500 μm. The metal surface layer is formed from a metal with excellent heat resistance and rigidity (e.g., nickel, stainless steel, etc.), and depending on the thickness and material, it may be a cylindrical plating layer or a metal sheet processed into a cylindrical shape.

[0068] For example, the metal elastic roll may be a heat-resistant rubber roll with a hardness of 90 degrees to which a metal band with a thickness of 380 μm is attached to the outer circumference, and the metal surface of the metal elastic roll may have a ten-point average roughness Rzjis of 0.2 μm or less. The ten-point average roughness Rzjis is measured in accordance with JIS B 0601:2001.

[0069] When a metal elastic roll is used for a long period of time, it gradually heats up, and the sleeve (metal band) of the metal elastic roll may expand due to heat and come off. Therefore, it is preferable to have a mechanism for cooling the surface of the metal elastic roll. Examples include cooling the entire roll by passing cooling water through it, or using the roll while cooling the sleeve with cold air. The process of cooling the surface of the metal elastic roll may be performed continuously or intermittently during the lamination process.

[0070] The heating method for the metal heating roll is not particularly limited, but dielectric heating or IR heating is preferable. In addition, a segmented heating type roll may be used to reduce shape changes due to the heat crown phenomenon. A segmented heating type is a method in which the roll is divided into multiple parts along the rotation axis and heated, and the heating temperature of each part is controlled individually. Furthermore, in order to reduce the effects of the heat crown phenomenon, the surface of the metal heating roll may be machined in advance, for example, by making the diameter of the center smaller than the diameters of both ends, so that it becomes flat when laminated.

[0071] From the viewpoint of reducing the thickness tolerance of the thermoplastic liquid crystal polymer layer, the surface temperature of the metal heating roll is preferably (Tm0-250) to (Tm0-10)°C, more preferably (Tm0-150) to (Tm0-30)°C, and even more preferably (Tm0-120) to (Tm0-60)°C, based on the melting point (Tm0) of the thermoplastic liquid crystal polymer resin.

[0072] In the manufacturing method of the present invention, the pressure between a pair of crimping rolls is preferably 0.1 to 30 kg / mm ​​in terms of linear pressure. More preferably 0.1 to 20 kg / mm, even more preferably 0.5 to 10 kg / mm, and particularly preferably 1.0 to 5.0 kg / mm. When the pressure between the pair of crimping rolls is within the above range, the film thickness tolerance of the thermoplastic liquid crystal polymer layer tends to be small.

[0073] The lamination of metal-clad laminates using metal elastic rolls may involve simply applying pressure to the metal foil and resin without calculating the gap between the metal elastic roll and the corresponding metal roll, or it may involve adjusting the thickness of the melt-extruded thermoplastic liquid crystal polymer layer by adjusting the gap between the pair of pressure rolls.

[0074] As an example, Figure 1 shows an apparatus 1 used in a method for manufacturing a metal-clad laminate according to one embodiment of the present invention. In the configuration shown in Figure 1, the apparatus 1 comprises a pair of compression rolls 10, an unwinding roll 30 for unwinding metal foil 20 toward the compression rolls 10, an extrusion device 50 for extruding molten resin 40 of thermoplastic liquid crystal polymer toward the compression rolls 10, a cooling roll 70 for cooling the metal-clad laminate (single-sided metal-clad laminate) 60 formed by the compression rolls 10, and a winding roll 80 for winding up the metal-clad laminate 60. The compression rolls 10 consist of a first roll 11 and a second roll 12. In this example, the first roll 11 is a metal roll (metal heating roll) equipped with a heating mechanism (not shown), and the second roll 12 is a metal elastic roll consisting of an elastic roll 12a and a metal layer 12b. The metal foil 20 unwound from the unwinding roll 30 is initially supplied to the first roll 11, heated on the outer surface 11a of the first roll 11, and then pressed with the molten resin 40. In the example shown, the extruder 50 includes a hopper 50a into which the resin raw material is fed, a kneading device 50b for heating and kneading the raw resin, a gear pump 50c, and an extruder die 50d for extruding the molten resin 40 supplied from the kneading device 50b via the gear pump 50c. The molten resin 40 extruded from the extruder die 50d is supplied between the first roll 11 and the second roll 12 of the pressing roll 10, pressed with the metal foil 20, and forms the thermoplastic liquid crystal polymer layer 60a of the metal-clad laminate 60.

[0075] Figure 2 shows an apparatus 2 used in a method for manufacturing a metal-clad laminate according to a second embodiment of the present invention. Components identical to those in apparatus 1 in Figure 1 are denoted by the same reference numerals and their descriptions are omitted. The apparatus 2 is equipped with two unwinding rolls 31 and 32. The first metal foil 21 unwound from the first unwinding roll 31 is supplied toward the first roll 11, which is made of a metal roll, heated on the outer surface 11a of the first roll 11, and then pressed with the molten resin 40. The second metal foil 22 is supplied from the second unwinding roll 32 toward the second roll 12, which is made of a metal elastic roll. The molten resin 40 extruded from the extrusion die 50d of the extrusion apparatus 50 is supplied onto the first roll 11 of the pressing roll 10 via the first metal foil 21, and pressed between the second metal foil 22 on the second roll 12 and the first metal foil 21 on the first roll to form a thermoplastic liquid crystal polymer layer 61a of a metal-clad laminate 61 made of a double-sided metal-clad laminate. Furthermore, if necessary, means for cooling the second roll (metallic elastic roll) 12 may be provided. In Figure 2, a cooling device 90 is provided to cool the second roll 12 with cold air, but cooling means (not shown) may also be provided inside the second roll 12.

[0076] The laminated metal-clad laminate may be heat-treated. The heat treatment process may be performed downstream of the lamination process without winding, or it may be performed after the lamination process and winding.

[0077] From the viewpoint of alleviating the strain on the thermoplastic liquid crystal polymer layer, heat treatment is preferably carried out by a non-contact heating method. Examples of known heating methods include ambient heating and radiant heating using electromagnetic waves such as infrared rays and microwaves, and examples of heat sources include hot air ovens, steam ovens, electric heaters, infrared heaters, ceramic heaters, and microwave irradiators.

[0078] The heat treatment temperature is preferably above the glass transition temperature (Tg) of the thermoplastic liquid crystal polymer layer. For example, the temperature may be between Tg and Tg+200°C, or in the range of Tg+5°C to Tg+150°C. The heat treatment time may be in the range of 10 to 180 seconds, preferably 15 to 120 seconds, and more preferably 20 to 90 seconds.

[0079] The heat treatment may be performed at a temperature above the melting point (Tm) of the thermoplastic liquid crystal polymer layer, but there are concerns about the influence of volatile components, etc. For example, the heat treatment may be performed at a temperature of Tm to Tm+50°C relative to the melting point Tm, or in the range of Tm+5°C to Tm+30°C. The heat treatment time may be in the range of 10 to 180 seconds, preferably 15 to 120 seconds, and more preferably 20 to 90 seconds.

[0080] This metal-clad laminate may be used as the metal-clad laminate of the present invention described below, or the laminated metal foil may be removed by etching and used as a thermoplastic liquid crystal polymer film.

[0081] (Thermoplastic liquid crystal polymer layer) The melting point (Tm) of the thermoplastic liquid crystal polymer layer is preferably in the range of 200 to 380°C, more preferably in the range of 260 to 370°C, even more preferably in the range of 300 to 360°C, even more preferably in the range of 305 to 355°C, and particularly preferably in the range of 310 to 350°C. It may also be 315°C or higher, preferably in the range of 315 to 380°C, more preferably in the range of 318 to 370°C, and even more preferably in the range of 320 to 360°C. The melting point (Tm) of the thermoplastic liquid crystal polymer layer can be obtained by observing the thermal behavior of the thermoplastic liquid crystal polymer layer sample using a differential scanning calorimeter. Specifically, the thermoplastic liquid crystal polymer layer sample is heated from room temperature (e.g., 25°C) at a rate of 10°C / min until it is completely melted at 400°C, then the molten material is cooled to 50°C at a rate of 10°C / min, and the position of the endothermic peak that appears when the temperature is raised again at a rate of 10°C / min can be determined as the melting point (Tm) of the thermoplastic liquid crystal polymer layer.

[0082] The thickness of the thermoplastic liquid crystal polymer layer of the metal-clad laminate can be set appropriately depending on the application. For example, when considering its use as an insulating layer material for a circuit board, it may be 10 to 500 μm, preferably 15 to 250 μm, more preferably 20 to 200 μm, and even more preferably 25 to 150 μm.

[0083] The present invention's method for manufacturing metal-clad laminates results in a small tolerance for the thickness of the thermoplastic liquid crystal polymer layer and excellent smoothness, making it suitable for use in components in fields such as electrical and electronics, office equipment and precision machinery, and power semiconductors, for example, as a circuit board material. [Examples]

[0084] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. In the following examples and comparative examples, various physical properties were measured by the methods described below.

[0085] [Method for measuring film thickness] For film thickness measurement, the copper foil of the metal-clad laminates prepared in the examples and comparative examples was etched to obtain a thermoplastic liquid crystal polymer layer (thermoplastic liquid crystal polymer film). From the resulting 530 mm wide thermoplastic liquid crystal polymer film, three sections measuring MD30 mm × TD500 mm were cut from adjacent parts in the MD direction (winding direction). Five measurements (L, LC, C, RC, R) were taken at 10 cm intervals in the width (TD) direction, with the center (C) as the reference point. Film thickness measurements were performed using a calibrated and inspected Mitutoyo Corporation micrometer MDC-25MX, and the average of three measurements was taken as the film thickness at each measurement point. Subsequently, the average value and standard deviation were calculated.

[0086] In the examples and comparative examples, metal elastic rolls may be abbreviated as MER, metal heating rolls as MR, heat-resistant rubber rolls as RR, metal foil (copper foil) as M, thermoplastic liquid crystal polymer resin as LCP, and thermoplastic liquid crystal polymer film as TR.

[0087] [Example 1] (Configuration: MR / M / LCP / MER) As shown in Figure 1, a thermoplastic liquid crystal polymer resin (a copolymer with a monomer composition of 77 mol% p-hydroxybenzoic acid and 23 mol% 6-hydroxy-2-naphthoic acid, melting point 310°C) was extruded at 340°C using the T-die casting method from an extruder equipped with a T-die with a die width of 600 mm and a lip opening of 1.0 mm. Meanwhile, copper foil (JX Metals Corporation: JXEFL-BHM foil, thickness 12 μm) was supplied between the compression rolls while being heated by contacting it with the outer surface of a metal heating roll heated to 230°C. The thermoplastic liquid crystal polymer resin extruded from the T-die and the heated copper foil were laminated between a metal heating roll with a diameter of 400 mm and a metal elastic roll with a diameter of 400 mm, while being pulled so that the thickness of the thermoplastic liquid crystal polymer layer was approximately 50 μm, thereby producing a single-sided metal-clad laminate. As the metal elastic roll, a heat-resistant rubber roll with a hardness of 90 degrees and a metal band with a thickness of 380 μm attached to its outer circumference was used. The metal surface of the metal elastic roll had a ten-point average roughness Rzjis of 0.2 μm or less. The pressure between the metal heating roll and the metal elastic roll was set as shown in Table 7.

[0088] [Example 2] (Configuration: MR / M / LCP / MER) A single-sided metal-clad laminate was fabricated in the same manner as in Example 1, except that the temperature of the metal heating roll was adjusted to 240°C, the thickness of the thermoplastic liquid crystal polymer layer was adjusted to approximately 25 μm, and the pressure between the metal heating roll and the metal elastic roll was changed to 1.9 kg / mm.

[0089] [Example 3] (Configuration: MER / M / LCP / MR) A thermoplastic liquid crystal polymer resin (a copolymer with a monomer composition of 77 mol% p-hydroxybenzoic acid and 23 mol% 6-hydroxy-2-naphthoic acid, melting point 310°C) was extruded at 340°C using the T-die casting method from an extruder equipped with a T-die with a die width of 600 mm and a lip opening of 1.0 mm. Meanwhile, copper foil (JX Metals Corporation: JXEFL-BHM foil, thickness 12 μm) was supplied between the compression rolls while in contact with the outer surface of the metal elastic roll. The thermoplastic liquid crystal polymer resin extruded from the T-die and the copper foil were laminated between a 400 mm diameter metal heating roll heated to 240°C and a 400 mm diameter metal elastic roll, taking up the material so that the thermoplastic liquid crystal polymer layer was approximately 50 μm thick, thereby producing a single-sided metal-clad laminate. The metal elastic roll used was a heat-resistant rubber roll with a hardness of 90 degrees, to which a 380 μm thick metal band was attached to the outer circumference. The metal surface of the metal elastic roll had a ten-point average roughness Rzjis of 0.2 μm or less. The pressure between the metal heating roll and the metal elastic roll was set as shown in Table 7.

[0090] [Example 4] (Configuration: MER / M / LCP / M / MR) A double-sided metal-clad laminate was fabricated in the same manner as in Example 3, except that metal foil was supplied to the metal heating roll and the metal elastic roll, and the temperature of the metal heating roll was changed to 230°C and the pressure between the metal heating roll and the metal elastic roll was changed to 2.8 kg / mm.

[0091] [Example 5] (Configuration: MER / M / LCP / M / MR) A double-sided metal-clad laminate was fabricated in the same manner as in Example 4, except that the temperature of the metal heating roll was changed to 250°C and the pressure between the metal heating roll and the metal elastic roll was changed to 1.9 kg / mm.

[0092] [Comparative Example 1] (Configuration: RR / M / LCP / MR) A single-sided metal-clad laminate was fabricated in the same manner as in Example 3, except that the metal elastic roll was replaced with a heat-resistant rubber roll (hardness 85).

[0093] [Comparative Example 2] (Configuration: MR / M / LCP / RR) A single-sided metal-clad laminate was fabricated in the same manner as in Example 2, except that the metal elastic roll was replaced with a heat-resistant rubber roll (hardness 85).

[0094] [Comparative Example 3] (Configuration: RR / M / LCP / MR) A single-sided metal-clad laminate was prepared in the same manner as in Comparative Example 1, except that the temperature of the metal heating roll was changed to 150°C.

[0095] [Comparative Example 4] (Configuration: MR / M / LCP / M / MR) A double-sided metal-clad laminate was fabricated in the same manner as in Example 5, except that the temperature of the metal heating roll was changed to 240°C and the metal elastic roll was replaced with a metal heating roll.

[0096] [Comparative Example 5] (Configuration: MER / TR / M / MR) A copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid (molar ratio: 77 / 23) was heated and kneaded in an extruder. After heating and kneading at 280-340°C using the extruder, the mixture was extruded through an inflation die with a diameter of 40 mm and a slit spacing of 0.6 mm to obtain a thermoplastic liquid crystal polymer film with a thickness of 50 μm. Subsequently, the thermoplastic liquid crystal polymer film at room temperature and copper foil (JX Metals Corporation: JXEFL-BHM foil, thickness 12 μm) were supplied between pressure rolls, and the thermoplastic liquid crystal polymer film and copper foil were laminated by passing them between a metal heating roll with a diameter of 400 mm and a metal elastic roll with a diameter of 400 mm, heated to 240°C, to produce a single-sided metal-clad laminate. The metal elastic roll used was a heat-resistant rubber roll with a hardness of 90 degrees, to which a metal band with a thickness of 380 μm was attached to the outer circumference. The metal surface of the metal elastic roll had a ten-point average roughness Rzjis of 0.2 μm or less. The pressure between the metal heating roll and the metal elastic roll was set as shown in Table 7.

[0097] The film thickness deviation of the thermoplastic liquid crystal polymer layer was evaluated for the metal-clad laminates of Examples 1-5 and Comparative Examples 1-5 using the method described above. The results are shown in Table 7.

[0098] [Table 7]

[0099] As shown in Table 7, Examples 1-5, which used metal elastic rolls, showed reduced variation in the film thickness of the thermoplastic liquid crystal polymer layer and a smaller standard deviation compared to Comparative Example 4, which used only metal heating rolls. In Comparative Examples 1-3, which used heat-resistant rubber rolls, the film thickness tolerance was small, but because the heat-resistant rubber rolls were heated by the resin extruded at 340°C, they gradually deteriorated, making it difficult to produce stable metal-clad laminates over the long term. Comparative Example 5, which used a room-temperature thermoplastic liquid crystal polymer film as the material to be pressed with the metal foil, showed a large standard deviation in film thickness. [Industrial applicability]

[0100] By using the manufacturing method for metal-clad laminates of the present invention, variations in the film thickness of the thermoplastic liquid crystal polymer layer can be reduced, and since it exhibits excellent smoothness, it can be effectively used as a circuit board material with excellent high-frequency characteristics in circuit applications.

[0101] As described above, preferred embodiments of the present invention have been explained, but those skilled in the art will readily anticipate various changes and modifications within the obvious scope by reviewing this specification. Therefore, such changes and modifications shall be construed as falling within the scope of the invention as defined by the claims. [Explanation of Symbols]

[0102] 2 Metal-clad laminate manufacturing equipment 10 Crimping Rolls 11. The first role 12. Second Roll 20, 21, 22 Metal foil 30, 31, 32 unwinding rolls 40 Molten resin 50 Extruder 60, 61 Metal-clad laminate 70 Cooling Rolls 80 reel rolls 90 Cooling device

Claims

1. A method for manufacturing a metal-clad laminate using a pair of pressure rolls, comprising a thermoplastic liquid crystal polymer layer containing a polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) and a metal foil disposed on at least one surface of the thermoplastic liquid crystal polymer layer, A method for manufacturing a metal-clad laminate, wherein the pair of compression rolls consist of a first roll and a second roll, both having metal surfaces, and the method comprises at least the steps of: supplying metal foil to the first roll and / or the second roll; supplying molten-extruded thermoplastic liquid crystal polymer resin between the first roll and the second roll; and lamination, wherein the supplied metal foil and thermoplastic liquid crystal polymer resin are passed between the pair of compression rolls to form a thermoplastic liquid crystal polymer layer on the metal foil, and the first roll and / or the second roll are metal elastic rolls.

2. A method for manufacturing a metal-clad laminate according to claim 1, wherein one of a pair of crimping rolls is a metal heating roll and the other roll is a metal elastic roll.

3. A method for manufacturing a metal-clad laminate according to claim 1 or 2, wherein the pressure between a pair of crimping rolls is 0.1 to 30 kg / mm ​​in terms of linear pressure.

4. A method for manufacturing a metal-clad laminate according to claim 1 or 2, comprising the step of cooling the surface of the metal elastic roll.

5. A method for manufacturing a metal-clad laminate according to claim 1 or 2, wherein the thickness of the metal foil is 6 μm or more and 35 μm or less.

6. A method for manufacturing a metal-clad laminate according to claim 1 or 2, wherein the thickness of the thermoplastic liquid crystal polymer layer is 5 μm or more and 300 μm or less.

7. A method for manufacturing a metal-clad laminate according to claim 1 or 2, further comprising a heating step of heating and drying the metal foil before supplying the metal foil to a pair of crimping rolls.

8. The manufacturing method according to claim 2, wherein the first roll is a metal roll, the second roll is a metal elastic roll, the metal roll is MR, the metal elastic roll is MER, the metal foil is M, and the thermoplastic liquid crystal polymer resin is LCP, and the arrangement of MR, MER, M, and LCP is as follows: MR / M / LCP / MER MR / LCP / M / MER, or MR / M / LCP / M / MER A method for manufacturing a metal-clad laminate, wherein the thermoplastic liquid crystal polymer resin supply process is carried out in such a manner.

9. The manufacturing method according to claim 2, wherein the first roll is a metal elastic roll, the second roll is a metal roll, and the metal elastic roll is MER, the metal roll is MR, the metal foil is M, and the thermoplastic liquid crystal polymer resin is LCP, and the arrangement of MER, MR, M, and LCP is as follows: MER / M / LCP / MR MER / LCP / M / MR, or MER / M / LCP / M / MR A method for manufacturing a metal-clad laminate, wherein the thermoplastic liquid crystal polymer resin supply process is carried out in such a manner.

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