Polyamic acid composition, and polyimide film and metal laminated plate using same

Abstract

The present invention provides: a polyamic acid composition comprising at least one diamine, at least one acid dianhydride, and an organic solvent, wherein the diamine further includes a diamine containing an alkyl group having 4 or more carbon atoms in a main chain or side chain thereof; and a metal laminated plate comprising a polyimide film formed by imidizing the polyamic acid composition. In the present invention, by including a diamine monomer containing an alkyl group having a predetermined number of carbon atoms, excellent processability can be exhibited through low viscosity and, at the same time, low dielectric loss, high adhesive strength, and excellent dimensional stability can be secured.

Description

Polyamic acid composition, polyimide film and metal laminate using the same

[0001] The present invention relates to a polyamic acid composition comprising a diamine monomer containing an alkyl group having a predetermined carbon number, a polyimide film formed from the composition and capable of simultaneously securing low dielectric loss, high adhesive strength, and excellent dimensional stability, and a metal laminate.

[0002]

[0003] Flexible Copper Clad Laminate (FCCL) is primarily used as a substrate for flexible printed circuit boards (FPCBs), but is also used in applications such as surface heating elements, electromagnetic shielding materials, flat cables, and packaging materials. As electronic devices using printed circuit boards become increasingly smaller, denser, and more efficient, the use of FCCL is increasing.

[0004] The above flexible copper-clad laminate is generally composed of a polyimide-based insulating layer and a copper foil layer. Such flexible copper-clad laminates can be broadly classified into flexible copper-clad laminates manufactured by laminating a copper foil layer on a polyimide film and flexible copper-clad laminates manufactured by laminating a polyimide layer on a copper foil layer, depending on the manufacturing method. In other words, flexible copper-clad laminates are classified into flexible copper-clad laminates manufactured by an adhesive method and flexible copper-clad laminates manufactured by a cast method.

[0005] Flexible copper-clad laminates manufactured by the adhesive method have a copper layer attached to a polyimide film using a separate adhesive, such as an epoxy adhesive. The final properties of flexible copper-clad laminates manufactured by this adhesive method, such as heat resistance, chemical resistance, flame retardancy, and electrical properties, are determined by the characteristics of the adhesive or adhesive film used. Consequently, the inherently excellent properties of polyimide resin, such as flexibility and heat resistance, cannot be fully realized.

[0006] Meanwhile, in the case of flexible copper-clad laminates manufactured by the casting method, instead of using an adhesive, a polyimide varnish is applied on the copper layer, and then a polyimide resin layer is formed on the copper layer by heat treatment under appropriate conditions. However, in the case of flexible copper-clad laminates manufactured by the casting method, the adhesive performance between the polyimide layer and the copper layer is low, so a separate thermoplastic polyimide must be used to ensure adhesion between the insulating layer and the copper layer, which leads to an increase in the production cost and a decrease in production efficiency. In addition, problems such as structural deformation of the flexible copper-clad laminate and printed circuit board and delamination between layers may occur due to the introduction of a multilayer insulating layer structure.

[0007]

[0008] The present invention has been made to solve the above-mentioned problems, and the technical task of the present invention is to provide a novel polyamic acid composition capable of simultaneously securing high adhesive strength, low dielectric loss factor, excellent flexibility and dimensional stability, etc., even without including a separate thermoplastic polyimide or adhesive, by changing the components of the polyamic acid composition constituting the polyimide and controlling the content thereof, a polyimide film formed from the composition, and a metal laminate having a polyimide insulating layer.

[0009] Other objects and advantages of the present invention can be more clearly explained by the detailed description of the invention and the claims below.

[0010]

[0011] To achieve the above-mentioned object, the present invention provides a polyamic acid composition comprising at least one diamine; at least one acid dianhydride; and an organic solvent, wherein the diamine further comprises a diamine containing an alkyl group having 4 or more carbon atoms in a main chain or a side chain.

[0012] In one embodiment of the present invention, the alkyl group may be a linear aliphatic alkyl group having 4 to 40 carbon atoms.

[0013] In one embodiment of the present invention, the diamine containing an alkyl group having 4 or more carbon atoms may be included in an amount of more than 0 mol% and less than or equal to 30 mol% based on 100 mol% of the diamine.

[0014] In one embodiment of the present invention, the diamine may further include a diamine containing one or more ester groups and an aromatic ring in the main chain.

[0015] In one embodiment of the present invention, the diamine containing the ester group and aromatic ring may be included in an amount of 5 to 30 mol% based on 100 mol% of the diamine.

[0016] In one embodiment of the present invention, the mixing ratio of the diamine containing an alkyl group having 4 or more carbon atoms and the diamine containing an ester group and an aromatic ring may be in the range of 1:1.1 to 1:5 mol%.

[0017] In one embodiment of the present invention, the at least one diamine may include at least one selected from the group consisting of fluorinated aromatic diamines, sulfonic aromatic diamines, hydroxyl aromatic diamines, ether aromatic diamines, non-fluorinated aromatic diamines, and alicyclic diamines.

[0018] In one embodiment of the present invention, the at least one acid dianhydride may include at least one selected from the group consisting of fluorinated aromatic acid dianhydrides, non-fluorinated aromatic acid dianhydrides, sulfonic aromatic acid dianhydrides, and alicyclic acid dianhydrides.

[0019] In one embodiment of the present invention, the polyamic acid composition may further include an inorganic filler.

[0020] In one embodiment of the present invention, the polyamic acid composition may have a viscosity of 10,000 to 50,000 cps at 25°C.

[0021] In addition, the present invention provides a polyimide film formed by imidizing the aforementioned polyamic acid composition.

[0022] The present invention also provides a metal laminate comprising at least one metal layer; and a polyimide film formed on one side of the metal layer or between the metal layers, and formed by imidizing the polyamic acid composition.

[0023] In one embodiment of the present invention, the metal laminate is formed by applying, drying, and imidizing a polyamic acid composition on a metal layer, and may not include a thermoplastic polyimide or an adhesive.

[0024] In one embodiment of the present invention, the metal layer may be selected from copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, or an alloy thereof.

[0025] In one embodiment of the present invention, the polyimide film may have a thickness of 1 to 50 μm.

[0026] In addition, the present invention provides a printed circuit board, specifically a flexible printed circuit board, comprising the aforementioned polyimide film.

[0027]

[0028] In one embodiment of the present invention, by using a diamine containing an alkyl group having a predetermined carbon number as a component of a polyamic acid composition constituting a polyimide, high adhesive strength, low dielectric loss factor, excellent flexibility and dimensional stability can be achieved simultaneously.

[0029] Furthermore, by eliminating the need for separate thermoplastic polyimide or adhesives, production costs can be reduced and production efficiency improved. Furthermore, the low viscosity of the polyamic acid composition can simplify the manufacturing process and reduce process costs.

[0030] In addition, since the present invention can manufacture a metal laminate by simply applying, drying, and imidizing a polyamic acid composition on a metal layer, it is possible to prevent issues such as deformation of a flexible metal laminate (FCCL) and a flexible printed circuit board (FPCB) or delamination between layers that occur when applying a multilayer structure insulating layer, thereby ensuring high reliability.

[0031] Accordingly, the polyamic acid composition according to the present invention can be usefully used as a low-k flexible metal laminate (FCCL) or flexible printed circuit board (FPCB) material for 5G mobile devices, specifically as an insulating layer material, and can be applied without limitation to various other technical fields.

[0032] The effects according to the present invention are not limited to those exemplified above, and more diverse effects are included in this specification.

[0033]

[0034] FIG. 1 is a drawing showing a method for measuring dimensional stability according to one embodiment of the present invention.

[0035]

[0036] Hereinafter, the present invention will be described in detail. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the present invention is not limited to the following embodiments. In this case, the same reference numerals indicate the same structures throughout the specification.

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0038] Additionally, throughout this specification, when a part is said to "include" a component, this does not exclude other components, but rather means that other components may be included, unless otherwise specifically stated. Furthermore, throughout this specification, "above" or "on" means not only when the target part is located above or below it, but also when there is another part in between, and does not necessarily mean that the target part is located above the direction of gravity.

[0039] <Polyamic acid composition>

[0040] An example of the present invention is a polyamic acid composition for forming a polyimide precursor [poly(amic acid), PAA] polymer, specifically a polyimide precursor solution for forming an insulating layer of a conventional flexible metal laminate board (FCCL) or flexible printed circuit board (FPCB) known in the art.

[0041] For example, the polyamic acid composition comprises at least one diamine; at least one acid dianhydride; and an organic solvent, wherein the diamine further comprises a diamine containing an alkyl group having 4 or more carbon atoms in the main chain or side chain. If necessary, at least one or more additives conventional in the art may be further included.

[0042] The alkyl group contained in the above diamine monomer is an aliphatic alkyl group having at least 4 carbon atoms, and is specifically an aliphatic alkyl group with a linear structure. This alkyl group suppresses charge transfer between polymer chains and induces the formation of voids, thereby reducing the dielectric loss of the polyimide resin itself. Accordingly, it can be applied as a low-k material that can accelerate signal transmission speed and reduce transmission loss.

[0043] In addition, the alkyl group contained in the above diamine monomer is relatively flexible and has a high degree of freedom compared to the conventional aromatic or alicyclic moieties with a rigid structure. Accordingly, the polyimide resin itself can exhibit excellent flexibility and stickiness by generating pores between the polymer chains. In particular, by including a predetermined aliphatic functional group, the adhesive properties with the substrate can be significantly improved compared to the conventional phenyl or ether group-containing diamine. Accordingly, even if a single polyimide insulating layer is provided without using a separate adhesive or thermoplastic polyimide, a flexible metal laminate and a printed circuit board having high adhesive strength, flexibility, and high reliability can be provided.

[0044] The diamine containing an alkyl group included as one component among the reactants of the polyamic acid composition according to the present invention is not particularly limited as long as it contains a diamine functional group in the molecule and an alkyl group having a predetermined carbon number in the main chain or side chain of the molecule.

[0045] At this time, in the case of an alkyl group having 3 or fewer carbon atoms, the effect of reducing dielectric loss is minimal, whereas if the carbon atoms are too large, processability and handling deterioration due to increased viscosity occur, and therefore, in the present invention, it is required to adjust the carbon atoms of the alkyl group included in the diamine to a predetermined range. Accordingly, in the present invention, an aliphatic alkyl group having at least 4 carbon atoms is used, and for example, it is preferable to use a diamine having a linear aliphatic alkyl group having 4 to 40 carbon atoms, specifically 5 to 38 carbon atoms, and more specifically 6 to 36 carbon atoms.

[0046] For example, the diamine containing an alkyl group having 4 or more carbon atoms may be further specified as a compound represented by the following chemical formulae 1 to 3. However, the present invention is not limited thereto.

[0047] [Chemical Formula 1]

[0048]

[0049] [Chemical Formula 2]

[0050]

[0051] [Chemical Formula 3]

[0052]

[0053] In the above chemical formulas 1 to 3,

[0054] n and m are the same or different, and are each independently an integer from 4 to 40. In addition, although not specifically indicated in the chemical formula, compounds in which the chemical formulas 1 to 3 described above are substituted with one or more substituents selected from the group consisting of halogen, -CF3, -OH, and amine groups known in the art also fall within the scope of the present invention.

[0055] Non-limiting examples of diamines containing alkyl groups having 4 or more available carbon atoms include Tetramethylenediamine, Hexamethylene diamine, Decamethylene diamine, Dodecamethylene diamine, Priamine, etc.

[0056] The content of the diamine containing an alkyl group having 4 or more carbon atoms according to the present invention is not particularly limited, and can be appropriately adjusted within a content range known in the art in consideration of the dielectric loss reduction effect. For example, the diamine containing an alkyl group having 4 or more carbon atoms may be included in an amount exceeding 0 mol% and 30 mol% or less based on 100 mol% of the diamine, and specifically, may be in the range of 5 to 20 mol%. When the content of the alkyl group-containing diamine falls within the above-mentioned range, a polyamic acid resin having high flexibility, adhesiveness, and high molecular weight can be formed while exhibiting the desired dielectric loss reduction effect, and when the content range is exceeded, a problem of reduced dimensional stability may occur.

[0057] The polyamic acid composition according to the present invention comprises at least one diamine (a) known in the art; and at least one acid dianhydride (b).

[0058] The above diamine (a) component is not limited to a compound having a diamine structure in the molecule, and for example, an aromatic, alicyclic, or aliphatic compound having a diamine structure, or a combination thereof, may be used. As specific examples, a fluorinated aromatic diamine having a fluorine substituent introduced therein, a sulfone-based aromatic diamine, a hydroxyl-based aromatic diamine, an ether-based aromatic diamine, a non-fluorinated aromatic diamine, or an alicyclic diamine may be used alone or in a mixed form of two or more thereof.

[0059] Non-limiting examples of usable diamine monomers (a) include p-phenylenediamine (PDA), oxydianiline (ODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (2,2'-TFDB), 2,2'-bis(trifluoromethyl)-4,3'-diaminobiphenyl (2,2'-Bis(trifluoromethyl)-4,3'-diaminobiphenyl), 2,2'-bis(trifluoromethyl)-5,5'-diaminobiphenyl (2,2'-Bis(trifluoromethyl)-5,5'-Diaminobiphenyl), 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6-FODA), bisaminohydroxyphenyl Hexafluoropropane (DBOH), bisaminophenoxy phenyl hexafluoropropane (4BDAF), bisaminophenoxy phenylpropane (6HMDA), bisaminophenoxy diphenylsulfone (DBSDA), bis(4-aminophenyl)sulfone (4,4'-DDS), bis(3-aminophenyl)sulfone (3,3'-DDS), sulfonyldiphthalic anhydride (SO2DPA), 4,4'-oxydianiline (4,4'-ODA), or a mixture of one or more of these can be applied.

[0060] For example, the fluorinated first diamine can be 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (2,2'-TFDB) or 1,4-Bis(4-amino-2-trifluoromethylphenoxy)benzene (6-FAPB), which can induce linear polymerization. In addition, the sulfonic second diamine can be bis(4-aminophenyl)sulfone (4,4'-DDS) or 3,3'-DDS. In addition, the hydroxyl third diamine can be 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, BIS-AP-AF). Additionally, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether (6-FODA) or oxydianiline (ODA) can be used as the ether-based quaternary diamine. Additionally, 2,2-bis(3-amino-4-methylphenyl)-hexafluoropropane (BIS-AT-AF), m-tolidine, or p-phenylenediamine (p-PDA) can be used as the non-fluorinated quaternary diamine. Non-limiting examples of usable cycloaliphatic diamines include 2,2-bis(3-amino-4-hydroxy cyclohexyl)hexafluoropropane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM), 4,4'-methylenebicyclohexylamine (PACM), 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)cyclohexane (1,4-BAC), cis-1,2-cyclohexanedimethaneamine, trans-1,2-cyclohexanedimethaneamine, 1,4-cyclohexyldiamine (CHDA), bis(4-aminocyclohexyl) ether, or mixtures thereof.

[0061] The content of at least one diamine monomer (a) selected from the above-mentioned fluorinated aromatic diamine, sulfonic aromatic diamine, hydroxyl aromatic diamine, ether aromatic diamine, non-fluorinated aromatic diamine, and alicyclic diamine is not particularly limited, and may be 0 to 100 mol%, specifically 10 to 90 mol%, and more specifically 20 to 80 mol%, based on 100 mol% of the total diamine. However, the content of at least one of the aromatic diamine and the alicyclic diamine is included so as to satisfy 100 mol% of the total diamine.

[0062] In the above diamine monomer (a), the mixing ratio of the non-fluorinated aromatic diamine and the ether diamine is 0 to 100:100 to 0:0 mol% based on 100 mol% of the total diamine, and specifically, it can be 10 to 90:90 to 10 mol%, and can be appropriately adjusted within a typical range known in the art.

[0063] For example, the mixing ratio of the non-fluorinated aromatic diamine, the ether diamine, and the diamine containing an alkyl group having 4 or more carbon atoms may be more than 40 to 65: 5 to 30: 0 mol% and less than 30 mol%, and more specifically, may be 50 to 65: 10 to 25: 5 to 20 mol%, based on 100 mol% of the total diamine. When the content ratio of the non-fluorinated aromatic diamine, the ether diamine, and the diamine containing an alkyl group having 4 or more carbon atoms falls within the above-mentioned range, a polyamic acid resin having desired high thermal properties and high adhesive strength can be formed.

[0064] Meanwhile, the present invention may further include a diamine containing one or more ester groups and aromatic rings in the main chain as a component of the diamine.

[0065] When such alkyl group-containing diamines / acid dianhydrides are mixed with diamines containing ester groups and aromatic rings, a synergistic effect can be achieved in terms of reducing the dielectric loss of the polyimide resin itself. Non-limiting examples of diamines containing ester groups and aromatic rings that can be used include APAB (4-Aminophenyl-4-aminobenzoate), ABHQ (1,4-Phenylene-di-4-aminobenzoate), or mixtures thereof.

[0066] The content of the diamine containing an ester group and an aromatic ring according to the present invention is not particularly limited, and can be appropriately adjusted within a content range known in the art, taking into account the effect of improving dimensional stability. For example, the diamine containing an ester group and an aromatic ring can be included in an amount of 5 to 30 mol% based on 100 mol% of the diamine, and specifically, in an amount of 10 to 20 mol%.

[0067] In addition, it is preferable to adjust the diamine containing an alkyl group having 4 or more carbon atoms and the diamine containing an ester group and an aromatic ring to a predetermined range in consideration of the effect of reducing dielectric loss. For example, the mixing ratio of the diamine containing an alkyl group having 4 or more carbon atoms and the diamine containing an ester group and an aromatic ring may be in the range of 1:1.1 to 1:5 mol%, and specifically, may be 1:1.2 to 1:4 mol%.

[0068] The acid dianhydride (b) monomer included in the polyamic acid composition of the present invention is not limited as long as it is a compound having an acid dianhydride structure in the molecule, and for example, an aromatic, alicyclic, or aliphatic compound having an acid dianhydride structure, or a combination thereof, etc. can be used. As specific examples, a fluorinated aromatic dianhydride having a fluorine substituent introduced therein, a non-fluorinated aromatic dianhydride, a sulfone-based aromatic dianhydride, or an alicyclic dianhydride can be used alone, or two or more of these can be used in a mixed form.

[0069] The above fluorinated dianhydride monomer is not particularly limited as long as it is an aromatic dianhydride with a fluorine substituent introduced therein. Non-limiting examples of usable fluorinated dianhydrides include 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6-FDA), 4-(trifluoromethyl)pyromellitic dianhydride (4-TFPMDA), or mixtures thereof.

[0070] In addition, the non-fluorinated dianhydride monomer is not particularly limited as long as it is a non-fluorinated aromatic dianhydride without a fluorine substituent introduced. Non-limiting examples of usable non-fluorinated tertiary acid dianhydride monomers include pyromellitic dianhydride (PMDA), 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride (BPDA), benzophenone tetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA), 4,4-(4,4-Isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA), bis(3,4dicarboxyphenyl)dimethylsilanedianhydride (SiDA), or mixtures thereof.

[0071] In addition, the sulfonic acid dianhydride monomer is not particularly limited as long as it is an acid dianhydride with a sulfonic group introduced, and an example is 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA).

[0072] Additionally, alicyclic acid dianhydrides are not particularly limited as long as they are compounds having an acid dianhydride structure and an alicyclic ring rather than an aromatic ring within the compound. Non-limiting examples of available cycloaliphatic dianhydrides include cyclobutane tetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentane tetracarboxylic dianhydride (CPDA), bicyclo[2,2,2]-7-octene-2,3,5,6-tetracarboxylic dianhydride (BCDA), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA), 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride (H-BPDA), 1,2,4,5-cyclohexane-tetracarboxylic dianhydride (H-PMDA), cyclopentanone bis-spironorbornane bis-spironorbornane, cpODA), Bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic2,3:5,6-dianhydride(7CI,8CI), or mixtures of one or more thereof.

[0073] The content of at least one acid dianhydride monomer (b) selected from the above-mentioned fluorinated aromatic dianhydride, non-fluorinated aromatic dianhydride, sulfonic aromatic dianhydride, and alicyclic dianhydride is not particularly limited, and may be 0 to 100 mol%, specifically 10 to 90 mol%, and more specifically 20 to 80 mol%, based on 100 mol% of the total acid dianhydride. However, the content of at least one of the above-mentioned aromatic dianhydride and alicyclic dianhydride is included so as to satisfy 100 mol% of the total acid dianhydride.

[0074] In the polyamic acid composition of the present invention, the ratio (a / b) of the number of moles of the diamine component (a) to the number of moles of the acid dianhydride component (b) may be in the range of 0.7 to 1.3, preferably 0.8 to 1.2, and more preferably 0.9 to 1.1.

[0075] In addition, the polyamic acid composition of the present invention can use any organic solvent known in the art as a solvent for the solution polymerization of the above-mentioned monomers without limitation. Examples of usable solvents include one or more polar solvents selected from m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), acetone, diethyl acetate, and dimethyl phthalate (DMP). In addition, low-boiling-point solutions such as tetrahydrofuran (THF) and chloroform, or solvents such as γ-butyrolactone, can be used. At this time, the content of the solvent (first solvent for polymerization) is not particularly limited, but in order to obtain an appropriate molecular weight and viscosity of the polyamic acid composition (polyamic acid solution), it is preferably included in an amount of 50 to 95 wt%, and more preferably 70 to 90 wt%, based on the total weight of the polyamic acid composition.

[0076] If necessary, the polyamic acid composition of the present invention may further include a conventional inorganic filler known in the art in consideration of dimensional stability, CTE improvement, mechanical properties, and stress reduction.

[0077] Non-limiting examples of usable inorganic fillers include silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, glass fiber, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, boron nitride, silicon nitride, talc, mica, etc. At this time, it is preferable to include at least one selected from the group consisting of talc, mica, silica, and calcium carbonate. In addition, the amount of the inorganic filler to be used is not particularly limited, and can be appropriately adjusted in consideration of the aforementioned bending characteristics, mechanical properties, etc.

[0078] In addition, the average particle diameter of the above-mentioned inorganic filler can be appropriately adjusted within a conventional range known in the art, and for example, can be in the range of 0.1 to 10 μm. If the average particle diameter of the above-mentioned inorganic filler is less than 0.1 μm, the surface area of ​​the inorganic filler may increase, resulting in poor dispersibility within the polyimide precursor solution. If the average particle diameter exceeds 10 μm, the inorganic filler may clump together on the exterior of the polyimide layer, resulting in poor appearance uniformity.

[0079] In the present invention, a polyamic acid composition can be prepared by introducing the aforementioned diamine, acid dianhydride, and alkyl group-containing diamine into a solvent and then reacting them. For example, a polyamic acid composition can be formed by including at least one diamine component, at least one acid dianhydride, and alkyl group-containing diamine, wherein the diamine (a) and the acid dianhydride (b) are in an equivalent ratio of approximately 1:1.

[0080] The polyamic acid composition configured as described above may have a viscosity (25°C) of about 10,000 to 50,000 cps, specifically 15,000 to 38,000 cps. When the viscosity of the polyamic acid composition falls within the above-mentioned range, the thickness of the polyamic acid composition can be easily controlled during coating, and the coating surface can be uniformly applied.

[0081] If necessary, the polyamic acid composition according to the present invention may further include one or more conventional additives known in the art, as long as they do not impede the purpose and effects of the invention described above. Specific examples of usable additives include plasticizers, antioxidants, flame retardants, dispersants, viscosity modifiers, leveling agents, catalysts, dehydrating agents, thermal conductivity improvers, electrical property improvers, wear resistance improvers, tracking resistance improvers, reinforcing agents, acid resistance improvers, dyes, and the like. These may be used alone or in combination of two or more.

[0082] Polyimide film

[0083] Another embodiment of the present invention is a polyimide film manufactured from the aforementioned polyamic acid composition, specifically, a polyimide film imidized by subjecting a polyamic acid resin solution formed by solution polymerization of a polyamic acid composition containing an alkyl group-containing diamine to cyclic dehydration at high temperature.

[0084] For example, the polyimide film is configured to include a polyimide having a weight average molecular weight (Mw) of 20,000 to 100,000 g / mol. More specifically, the polyimide resin may have a weight average molecular weight (Mw) of 40,000 to 60,000 g / mol.

[0085] The polyimide film according to the present invention can be manufactured according to a conventional method known in the art, and for example, can be manufactured by coating, drying, and imidizing a polyamic acid composition on a substrate.

[0086] The method for coating the above polyamic acid composition onto a substrate is not particularly limited, and any conventional coating method known in the art can be used without limitation. For example, various methods can be used, such as casting, dip coating, die coating, roll coating, slot die, comma coating, or a combination thereof.

[0087] At this time, the substrate may be a conventional substrate known in the art, preferably a metal substrate or a heat-resistant polymer substrate capable of withstanding a curing temperature of 100°C or higher. Furthermore, the drying and imidization processes may be appropriately performed under conventional conditions known in the art. For example, drying may be performed at 100 to 200°C, and the imidization process may be performed at 300 to 400°C for 5 to 60 minutes.

[0088] The thickness of the polyimide film manufactured as described above is not particularly limited and can be appropriately adjusted within a range known in the art. For example, to ensure excellent low-dielectric properties, mechanical properties, and dimensional stability, the film may have a thickness of 5 to 100 μm, preferably 7 to 80 μm, and more preferably 10 to 50 μm.

[0089] <Metal laminated plate>

[0090] Another embodiment of the present invention is a metal clad laminate, specifically a flexible metal clad laminate including a polyimide insulating layer or polyimide film formed by imidizing the polyamic acid composition described above.

[0091] The metal laminate may have a single-sided or double-sided structure in which a metal layer is disposed on one or both sides of the insulating layer based on the insulating layer. More specifically, the metal laminate includes at least one metal layer; and a polyimide insulating layer formed on one side of the metal layer or between the metal layers, and formed by imidizing a polyamic acid composition containing a predetermined alkyl group-containing diamine / acid dianhydride.

[0092] The metal layer may be a metal or alloy known in the art that is conductive and ductile, and may be selected from, for example, copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, or alloys thereof. Preferably, it may be a copper foil. Examples of usable copper foils include CFL (TZA_B, HFZ_B), Mitsui (HSVSP, MLS-G), Nikko (RTCHP), Furukawa, ILSIN, etc. In addition, the copper foil may be a rolled copper foil or an electrolytic copper foil, and a copper foil treated to prevent oxidation and corrosion of the surface may be used.

[0093] Additionally, the metal layer may have a surface roughness (Rz) formed on the surface in contact with the polyimide insulating layer. At this time, the range of the surface roughness (Rz) is not particularly limited, and may be, for example, 0.6 to 3.0 ㎛. The thickness of the metal layer is not particularly limited, but considering the thickness and mechanical properties of the metal laminate, it may be less than 5 ㎛, and is preferably 1 to 3 ㎛.

[0094] The thickness of the above polyimide insulating layer is not particularly limited and can be appropriately adjusted within a range known in the art. For example, it may have a thickness of 1 to 50 μm, specifically 5 to 50 μm, and more specifically 7 to 50 μm. Since the composition of the polyimide insulating layer is otherwise the same as described above, a separate description thereof will be omitted.

[0095] Meanwhile, the metal laminate according to the present invention is differentiated from the conventional metal laminate in that it forms a polyimide insulating layer by applying, drying, and imidizing a polyamic acid composition on a metal layer, but does not contain thermoplastic polyimide or an adhesive. In particular, the metal laminate of the present invention can have a low dielectric loss factor (Df) due to the reduction in dielectric loss of the polyimide itself, and can also exhibit excellent flexibility and high adhesive strength even if it does not contain thermoplastic polyimide and / or an adhesive.

[0096] For example, the metal laminate may have a dielectric loss (Df) of 0.007 or less measured at a frequency of 10 GHz or more and 28 GHz or less, an adhesion strength of a polyimide insulating layer to a metal layer of 0.7 kgf / cm or more according to IPC-TM-650 2.4.9, a dimensional change rate in the MD direction of within ±0.2% according to IPC-TM-650 2.2.4, and a dimensional change rate in the TD direction of within ±0.2%. More specifically, the dielectric loss (Df) measured at a frequency of 10 GHz or more and 28 GHz or less may be 0.0020 to 0.0069, and 0.0022 to 0.0040. In addition, the adhesion of the polyimide insulating layer to the metal layer according to IPC-TM-650 2.4.9 is 0.7 to 1.5 kgf / cm, the dimensional change rate in the MD direction according to IPC-TM-650 2.2.4 is within ±0.15%, and the dimensional change rate in the TD direction can be within ±0.15%.

[0097]

[0098] Printed circuit board

[0099] Another embodiment of the present invention is a printed circuit board, specifically a flexible printed circuit board (FPCB) including a polyimide insulating layer or polyimide film formed by imidizing the aforementioned polyamic acid composition.

[0100] Such printed circuit boards may be single-layer or multi-layer printed circuit boards comprising at least one metal circuit pattern.

[0101] The printed circuit board according to the present invention can be manufactured by methods known in the art. Specifically, it can be manufactured by forming a through-hole in at least one of the aforementioned metal laminates, for example, a copper-clad laminate, performing through-hole plating, and then etching the copper foil to form a circuit.

[0102] The polyamic acid composition of the present invention, the polyimide film, the metal laminate, and the printed circuit board using the same are manufactured by including the diamine / acid dianhydride having the above-described predetermined carbon alkyl group, and therefore have a low dielectric loss factor (Df), and can exhibit high adhesive strength, excellent flexibility, and dimensional stability even without a separate thermoplastic polyimide and / or adhesive. Accordingly, the metal laminate and the printed circuit board of the present invention can be usefully used as a metal laminate and / or printed circuit board applied to various electrical and electronic devices such as mobile communication devices handling high-frequency signals of 1 GHz or higher, base station devices thereof, network-related electronic devices such as servers and routers, and large-scale computers, and is particularly preferably applied to a low-k metal laminate (FCCL) for 5G mobile devices. In addition, it can be applied to various technical fields requiring a low dielectric loss factor, high adhesive strength, excellent flexibility, and dimensional stability.

[0103] Hereinafter, the present invention will be described in detail through examples. However, the following examples are only illustrative of the present invention, and the present invention is not limited to the following examples.

[0104]

[0105] [Examples 1-5]

[0106] A polyamic acid composition was prepared using a composition including a diamine and an acid dianhydride as described in Table 1 below. Specifically, as the diamine component, PDA (p-phenylenediamine), m-TB (m-Tolidine), ODA (4,4'-Diaminodiphenylether), APAB (4-Aminophenyl-4-aminobenzoate), ABHQ (1,4-Phenylene-di-4-aminobenzoate), TrA (Trimethylenediamine, n = 3), TeA (Tetramethylenediamine, n = 4), and PA (Priamine 1075, n = 36) were used, and as the acid dianhydride component, BPDA (3,3',4,4'-Biphenyltetracarboxylic Dianhydride) was used.

[0107] The above polyamic acid composition was applied onto a substrate (copper foil: 12 μm thick) and dried at 100 to 200°C for 5 to 15 minutes. Thereafter, heat treatment was performed at 300 to 400°C for 20 minutes or more for imidization. At this time, the molecular weight (Mw) of the polyimide precursor was 20,000 g / mol or more. Accordingly, a polyimide film having a final film thickness of approximately 20 μm and a copper-clad laminate (FCCL) in which the polyimide film and the copper foil are laminated were manufactured, respectively.

[0108] Diamine (mol) Acid dianhydride (mol) PDAm-TBODA Ester group containing Diamine alkyl group containing Diamine APABABHQTrA(n=3)TeA(n=4)PA(n=36)BPDAExample 10.40.20.150.2---0.051Example 20.40.20.050.2---0.151Example 30.40.20.150.2--0.051Example 40.40.20.15-0.2--0.051Example 50.40.20.35----0.051Comparative Example 10.40.20.4-----1Comparative Example 20.40.20.35--0.05--1Comparative Example 30.40.20.2-0.2--1Comparative Example 40.40.20.15-0.20.05--1

[0109]

[0110] [Comparative Examples 1-4]

[0111] Polyimide films and copper-clad laminates of Comparative Examples 1 to 4 were manufactured in the same manner as in Examples 1 to 5, except that the compositions described in Table 1 above were used.

[0112]

[0113] [Experimental Example: Physical Property Evaluation]

[0114] The properties of the polyimide films and copper-clad laminates manufactured in Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated using the following methods, and the results are shown in Table 2 below. In this case, each property in Table 1 below is based on a polyimide film thickness of 12 μm.

[0115] <Method of property evaluation>

[0116] 1) Viscosity measurement

[0117] After preparing a polyimide precursor resin without bubbles in a 100 mL sample bottle, the room temperature viscosity was measured using a viscometer (Brookfield).

[0118] 2) Measurement of dielectric loss (Df)

[0119] After preparing a 9*10cm specimen, it was etched and dried at 110℃ for 1 hour. Afterwards, it was stored in a constant temperature and humidity chamber at 23℃ / 50% for 24 hours, and the 10GHz Resonance Cavity was measured using a Keysight Network Analyzer in a moisture-absorbing state.

[0120] 3) Adhesion measurement

[0121] Adhesion was measured according to the IPC-TM-650 2.4.9 standard. Specifically, a 1 mm pattern was formed on the copper foil surface, and the adhesion between the copper foil and the polyimide film was measured by pulling the copper foil surface at a 90° angle using a Shimadzu UTM (Universal Testing Machine).

[0122] 4) Measurement of dimensional stability after heating

[0123] The dimensional stability after heating was measured according to the IPC-TM-650 2.2.4 standard. As shown in Fig. 1 below, a sample with a size of 30 cm (MD) * 27 cm (TD) was prepared, and holes were created at intervals of 25 cm in the MD direction and 23 cm in the TD direction within the sample. The sample with holes created was etched, and the interval between the holes (initial interval) was measured. Subsequently, the sample was heat-treated at 150°C for 30 minutes and stored at room temperature for 24 hours. The interval between the holes (final interval) was measured again, and the dimensional change rate was measured according to the following mathematical equations 1 and 2. In the measured dimensional change rate, a positive value indicates elongation, and a negative value indicates shrinkage.

[0124] [Mathematical Formula 1]

[0125]

[0126] [Equation 2]

[0127]

[0128] In the above formulas 1 and 2,

[0129] MD = dimensional change rate in the longitudinal direction (MD),

[0130] TD = rate of change in dimension in the transverse direction (TD),

[0131] (AB)i = initial interval between points A and B,

[0132] (AB)f = the later interval between points A and B,

[0133] (AC)i = initial spacing between points A and C,

[0134] (AC)f = the later interval between points A and C,

[0135] (CD)i = initial spacing between points C and D,

[0136] (CD)f = the later interval between points C and D,

[0137] (BD)i = initial spacing between points B and D,

[0138] (BD)f = the later interval between points B and D.

[0139] ViscosityDielectric LossAdhesionDimensional Stability After Heating[MD / TD](cPs)(Df)(kgf / cm)(%)Example 132,0000.00281= -0.05 / -0.09Example 223,0000.00220.95= -0.1 / -0.14Example 337,0000.00351= -0.06 / -0.07Example 433,0000.00271= -0.07 / -0.08Example 535,0000.00331.05= -0.07 / -0.08Comparative Example 141,0000.00751.05= -0.02 / -0.04Comparative Example 239,0000.00711= -0.03 / -0.06Comparative Example 336,0000.00441= -0.03 / -0.05Comparative Example 435,0000.00430.95= -0.04 / -0.07

[0140] As shown in Table 2 above, in the case of Examples 1 to 4 including a diamine containing an alkyl group having a predetermined carbon number, it was found that not only was the processability excellent due to the appropriate viscosity, but also low dielectric loss, high adhesive strength, and excellent dimensional stability were secured at the same time.

[0141] Specifically, Examples 1 to 5 using a diamine having 4 or more carbon atoms exhibited lower dielectric loss characteristics and viscosity characteristics compared to Comparative Examples 1 to 4 not including the diamine or including a diamine having 3 carbon atoms in the alkyl group. In particular, as the number of carbon atoms contained in the diamine increased, the dielectric loss characteristics of the polyimide film showed an effect of improving. In addition, it was confirmed that when a diamine having 4 or more carbon atoms and a diamine containing an ester group were mixed, a better effect was exhibited in terms of dimensional stability after heating.

Claims

1. At least one diamine; At least one acid anhydride; and Contains organic solvents; A polyamic acid composition wherein the above diamine further comprises a diamine containing an alkyl group having 4 or more carbon atoms in the main chain or side chain.

2. In paragraph 1, A polyamic acid composition, wherein the alkyl group is a linear aliphatic alkyl group having 4 to 40 carbon atoms.

3. In paragraph 1, A polyamic acid composition wherein the diamine containing an alkyl group having 4 or more carbon atoms is selected from compounds represented by the following chemical formulas 1 to 3: [Chemical Formula 1] [Chemical formula 2] [Chemical Formula 3] In the above chemical formulas 1 to 3, n and m are equal to or different from each other and are each independently an integer from 4 to 40.

4. In paragraph 1, A polyamic acid composition, wherein the diamine containing an alkyl group having 4 or more carbon atoms is contained in an amount of more than 0 mol% and less than or equal to 20 mol% based on 100 mol% of the diamine.

5. In paragraph 1, A polyamic acid composition further comprising a diamine having at least one ester group and an aromatic ring in the main chain.

6. In paragraph 5, A polyamic acid composition, wherein the diamine containing the above ester group and aromatic ring is included in a range of 5 to 30 mol% based on 100 mol% of the diamine.

7. In paragraph 5, A polyamic acid composition wherein the mixing ratio of the diamine containing an alkyl group having 4 or more carbon atoms and the diamine containing an ester group and an aromatic ring is in the range of 1:1.1 to 1:5 mol%.

8. In paragraph 1, A polyamic acid composition comprising at least one diamine selected from the group consisting of fluorinated aromatic diamines, sulfonic aromatic diamines, hydroxyl aromatic diamines, ether aromatic diamines, non-fluorinated aromatic diamines, and alicyclic diamines.

9. In paragraph 1, A polyamic acid composition, wherein the at least one acid dianhydride comprises at least one selected from the group consisting of a fluorinated aromatic acid dianhydride, a non-fluorinated aromatic acid dianhydride, a sulfonic aromatic acid dianhydride, and an alicyclic acid dianhydride.

10. In paragraph 1, A polyamic acid composition further comprising an inorganic filler.

11. In paragraph 1, A polyamic acid composition having a viscosity of 10,000 to 50,000 cps at 25°C.

12. A polyimide film formed by imidizing the polyamic acid composition according to any one of claims 1 to 11.

13. In paragraph 12, The above polyimide film is a polyimide film having a weight average molecular weight (Mw) of 20,000 g / mol to 100,000 g / mol.

14. At least one metal layer; and A polyimide insulating layer formed by imidizing the polyamic acid composition according to any one of claims 1 to 11, formed on one side of the metal layer or between the metal layers; A metal laminate comprising:

15. In paragraph 14, The above metal laminated plate, A polyamic acid composition is applied on a metal layer, dried, and imidized to form a polyimide insulating layer. A metal laminate, which does not contain a thermoplastic polyimide or adhesive.

16. In paragraph 14, The above metal layer is a metal laminate selected from copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten or alloys thereof.

17. In paragraph 14, A metal laminated plate, wherein the polyimide insulating layer has a thickness of 1 to 50 ㎛.

18. In paragraph 14, The above metal laminated plate, The dielectric loss (Df) measured at a frequency of 10 GHz or more and 28 GHz or less is 0.007 or less, The adhesion of the polyimide insulating layer to the metal layer according to IPC-TM-650 2.4.9 is 0.7 kgf / cm or more, A metal laminate having a dimensional change rate of within ±0.2% in the MD direction and a dimensional change rate of within ±0.2% in the TD direction according to IPC-TM-650 2.2.

4.

19. A printed circuit board comprising a polyimide film of clause 12.

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