CN119217819A

CN119217819A - Laminated body, metal-clad laminate, circuit board, electronic component and device, adhesive resin composition and preparation method, and adhesive film

Info

Publication number: CN119217819A
Application number: CN202410819065.2A
Authority: CN
Inventors: 髙村真辉
Original assignee: Nippon Steel and Sumikin Chemical Co Ltd
Current assignee: Nippon Steel Chemical and Materials Co Ltd
Priority date: 2023-06-29
Filing date: 2024-06-24
Publication date: 2024-12-31
Also published as: KR20250001927A; TW202500383A; JP2025006070A

Abstract

The invention provides a laminate, a metal-clad laminate, a circuit board, an electronic component, an electronic device, an adhesive resin composition, a method for producing the same, and an adhesive film. The laminate comprises a first insulating resin layer, a second insulating resin layer, and an adhesive layer laminated between the layers, wherein the total thickness T1 of the laminate is in the range of 70-500 [ mu ] m, the thickness T2 of the adhesive layer is in the range of more than 50 [ mu ] m and not more than 450 [ mu ] m, and the ratio (T2/T1) of T2 to T1 is in the range of more than 0.5 and not more than 0.96. The adhesive layer contains a resin component and a filler component, the resin component contains polyimide, and the polyimide contains more than 40 mol% of diamine residues which are derived from a dimer diamine composition, wherein the dimer diamine composition takes dimer diamine with two terminal carboxylic acid groups of dimer acid substituted into primary amino methyl groups or amino groups as a main component.

Description

Laminate, metal-clad laminate, circuit board, electronic component, device, adhesive resin composition, method for producing the same, and adhesive film

Technical Field

The present invention relates to a laminate, a metal-clad laminate, a circuit board, an electronic component, an electronic device, an adhesive resin composition, a method for producing the same, and an adhesive film, which are useful as materials for electronic parts.

Background

In recent years, along with the progress of miniaturization, weight reduction, and space saving of electronic devices, there has been an increasing demand for flexible printed wiring boards (Flexible Printed Circuits, FPCs) which are thin and lightweight, have flexibility, and have excellent durability even if repeatedly bent. Since FPC can be mounted in a three-dimensional and high-density manner even in a limited space, its use is expanding in parts such as wiring, cables, connectors, etc. of electronic devices such as hard disk drives (HARD DISK DRIVE, HDD), digital versatile discs (DIGITAL VERSATILEDISK, DVD), smart phones, etc.

In addition to the higher density, the higher performance of the device is advancing, and therefore, it is also necessary to cope with the higher frequency of the transmission signal. When a high-frequency signal is transmitted, if the transmission loss in the transmission path is large, there occurs a problem such as loss of the electrical signal or a longer delay time of the signal. In order to cope with the high frequency of the transmission signal, it has been proposed to improve the dielectric characteristics by interposing an adhesive layer having a large thickness ratio between insulating resin layers of a pair of single-sided metal-clad laminated plates and using thermoplastic polyimide as a material of the adhesive layer, the thermoplastic polyimide being a material of dimer acid diamine (DDA) in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups (patent document 1). In the layer structure as in patent document 1, in order to further improve the dielectric characteristics, it is effective to increase the thickness of the inner layer portion including the adhesive layer excellent in dielectric characteristics, and to increase the thickness ratio with respect to the entire resin layer.

However, if the thickness of the inner layer portion including the aliphatic group having low polarity is increased and the thickness ratio to the entire resin layer is increased, the flame retardancy is impaired, and therefore, further improvement of the dielectric characteristics is hindered.

Further, if the thickness of the inner layer portion is increased, thickness unevenness during coating tends to occur, and if the thickness unevenness is large, variation in characteristic impedance becomes large, and thus, adverse effects such as a loss of transmission signals becoming large also occur.

Further, when an elongated adhesive film and a single-sided metal-clad laminate are laminated in a roll-to-roll (roll-to-roll) manner, the adhesive film is too soft, and therefore there is a problem that wrinkles are easily generated due to shear stress at the time of lamination.

[ Prior Art literature ]

[ Patent literature ]

Patent document 1 Japanese patent laid-open publication No. 2018-170417

Disclosure of Invention

[ Problem to be solved by the invention ]

The purpose of the present invention is to provide a laminate which has excellent dielectric properties and flame retardancy that can be applied to a high-frequency circuit board, and which can also suppress the occurrence of uneven thickness of an adhesive layer or wrinkles during lamination.

[ Means of solving the problems ]

The present inventors have made an intensive study, and as a result, focused on fluidity of an adhesive varnish or a tensile modulus of elasticity of an adhesive film and a storage modulus of elasticity in the vicinity of a lamination temperature as factors of thickness unevenness of an adhesive layer and generation of wrinkles at the time of lamination. Further, it has been found that when an adhesive layer having a large thickness and a low dielectric loss tangent is provided in an inner layer portion and a filler component is blended in the adhesive layer at a high concentration, and the tensile modulus and the storage modulus are appropriately controlled, the thickness unevenness and wrinkles during lamination can be improved, and the low dielectric loss tangent can be achieved while ensuring excellent flame retardancy, and the present invention has been completed.

That is, the laminate according to the first aspect of the present invention includes a first insulating resin layer, a second insulating resin layer, and an adhesive layer laminated between the first insulating resin layer and the second insulating resin layer so as to be in contact with each other.

In the laminate according to the first aspect of the present invention, the total thickness T1 of the first insulating resin layer, the adhesive layer, and the second insulating resin layer is in the range of 70 μm to 500 μm, the thickness T2 of the adhesive layer is in the range of more than 50 μm and not more than 450 μm, and the ratio (T2/T1) of T2 to T1 is in the range of more than 0.5 and not more than 0.96.

In the laminate according to the first aspect of the present invention, the adhesive layer contains a resin component and a filler component,

The resin component contains a polyimide having a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component, and contains 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, relative to the total diamine residues.

In the laminate according to the first aspect of the present invention, the filler component contains a metal salt of an organic phosphinic acid, and the weight ratio of the filler component to 100 parts by weight of the total amount of the resin components is in a range of more than 40 parts by weight and 90 parts by weight or less.

In the laminate according to the first aspect of the present invention, the total area ratio of the filler component having a particle diameter of more than 10 μm and the filler-removed portion having a length of more than 10 μm in the area view of 100 μm×100 μm when the adhesive layer is observed by a scanning electron microscope on the cross section in the thickness direction may be 1% or less on the average of the area views of arbitrary ten portions.

In the laminate according to the first aspect of the present invention, the polyimide may be a polyimide having a ketone group in a molecule, and the resin component may contain a crosslinking agent having a functional group that reacts with the ketone group in a nucleophilic manner.

In the laminate of the first aspect of the present invention, the polyimide may have a crosslinked structure by a reaction between a ketone group in the molecule and a crosslinking agent having a functional group that undergoes a nucleophilic reaction with respect to the ketone group.

In the laminate according to the first aspect of the present invention, the adhesive layer may have a tensile elastic modulus in a range of 1.0GPa to 1.2 GPa.

The laminate according to the first aspect of the present invention may have a storage modulus of elasticity of the adhesive layer at 80 ℃ in a range of 10MPa to 20 MPa.

In the laminate according to the first aspect of the present invention, the first insulating resin layer and the second insulating resin layer may be a multilayered polyimide layer having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer. In that case, the outermost layer of the multi-layer polyimide layer may be a thermoplastic polyimide layer.

The laminate according to the first aspect of the present invention may have a length in the width direction (transverse direction (TRANSVERSE DIRECTION, TD)) in a range of 0.2m to 2.0m, and may have a long shape.

The metal-clad laminate according to the second aspect of the present invention comprises the laminate according to the first aspect, and a metal layer laminated on one or both surfaces of the laminate.

The circuit board according to the third aspect of the present invention comprises the laminate according to the first aspect, and a wiring layer laminated on one or both surfaces of the laminate.

An electronic component according to a fourth aspect of the present invention includes the circuit board according to the third aspect.

An electronic device according to a fifth aspect of the present invention includes the circuit board according to the third aspect.

The adhesive resin composition according to the sixth aspect of the present invention is an adhesive resin composition comprising a resin component, a filler component and an organic solvent.

In the adhesive resin composition according to the sixth aspect of the present invention, the resin component contains a polyimide having a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component, and 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, relative to all diamine residues.

In the adhesive resin composition according to the sixth aspect of the present invention, the filler component contains a metal salt of an organic phosphinic acid, and the weight ratio of the filler component to 100 parts by weight of the total amount of the resin components is in a range of more than 40 parts by weight and 90 parts by weight or less.

In the adhesive resin composition according to the sixth aspect of the present invention, the tensile modulus of elasticity when forming a film at a thickness in the range of more than 50 μm and not more than 450 μm is in the range of 1.0GPa to not more than 1.2GPa, and the storage modulus of elasticity at 80℃is in the range of 10MPa to not more than 20 MPa.

The method for producing an adhesive resin composition according to the seventh aspect of the present invention is a method for producing the adhesive resin composition according to the sixth aspect.

The method for producing an adhesive resin composition according to the seventh aspect of the present invention comprises the following steps (i) and (ii);

(i) A step of mixing and stirring a part of the resin component and the filler component in an organic solvent to obtain a filler dispersion, and

(Ii) And mixing the remaining part of the resin component with an organic solvent into the filler dispersion and stirring the mixture to obtain the adhesive resin composition.

In the method for producing an adhesive resin composition according to the seventh aspect of the present invention, in the step (i), the weight ratio of the resin component in the filler dispersion is set to be in the range of 3 parts by weight to 15 parts by weight relative to 100 parts by weight of the final total amount of the resin components, and the solid content concentration in the filler dispersion is adjusted to be in the range of 40% by weight to 60% by weight, and in the step (ii), the weight ratio of the filler component in the adhesive resin composition is set to be in the range of more than 40 parts by weight and 90 parts by weight or less relative to 100 parts by weight of the final total amount of the resin components.

The adhesive film according to the eighth aspect of the present invention is an adhesive film containing a resin component and a filler component.

In the adhesive film according to the eighth aspect of the present invention, the resin component contains a polyimide having a tetracarboxylic acid residue derived from a tetracarboxylic anhydride component and a diamine residue derived from a diamine component, and contains 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, relative to the total diamine residues.

In the adhesive film according to the eighth aspect of the present invention, the filler component contains a metal salt of an organic phosphinic acid, and the weight ratio of the filler component to 100 parts by weight of the total amount of the resin components is in a range of more than 40 parts by weight and 90 parts by weight or less.

In the adhesive film according to the eighth aspect of the present invention, the thickness is in the range of more than 50 μm and not more than 450 μm, the tensile elastic modulus is in the range of 1.0GPa to 1.2GPa, and the storage elastic modulus at 80℃is in the range of 10MPa to 20 MPa.

[ Effect of the invention ]

The laminate of the present invention is provided with an adhesive layer having a large thickness and a low dielectric loss tangent at the inner layer portion, and the filler component is blended in the adhesive layer at a high concentration, whereby the tensile modulus and the storage modulus are appropriately controlled, and therefore, the occurrence of thickness unevenness and wrinkles at the time of lamination can be suppressed, and both excellent dielectric characteristics and flame retardancy can be achieved. Therefore, for example, in the application to a circuit board transmitting a high-frequency signal of 10GHz or more, the metal-clad laminate using the laminate of the present invention can realize a reduction in transmission loss and an improvement in reliability and safety.

Drawings

Fig. 1 is a schematic cross-sectional view showing the layer structure of a laminate according to a preferred embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a layer structure of a laminate according to another preferred embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view showing the layer structure of a metal-clad laminate according to a preferred embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing a layer structure of a metal-clad laminate according to another preferred embodiment of the present invention.

Fig. 5 is a scanning electron microscope image of a cross section of the adhesive sheet obtained in example 5.

Fig. 6 is a scanning electron microscope image of a cross section of the adhesive sheet obtained in comparative example 5.

[ Description of symbols ]

10A, 10B thermoplastic polyimide layer

20A, 20B non-thermoplastic polyimide layer

30A, 30B thermoplastic polyimide layer

40A first insulating resin layer

40B second insulating resin layer

100. 101 Laminate

110A, 110B metal layer

200. 201 Metal clad laminate

AD adhesive layer

Detailed Description

Embodiments of the present invention will be described with reference to the accompanying drawings.

[ Laminate ]

In the laminate according to an embodiment of the present invention, the first insulating resin layer, the adhesive layer, and the second insulating resin layer are sequentially laminated. The low dielectric loss tangent adhesive layer is formed to be thick between two insulating resin layers, thereby forming a laminate (laminated resin film) having a low dielectric loss tangent and a large thickness. In addition, by sandwiching the adhesive layer having a large dimensional change with the insulating resin layer having a small dimensional change, dimensional stability can be ensured. Further, by sandwiching the adhesive layer between two insulating resin layers, moisture absorption and water absorption of the adhesive layer can be suppressed, and deterioration of dielectric loss tangent can be alleviated.

Fig. 1 shows a cross-sectional structure of a laminate 100 according to a preferred embodiment of the present invention. The laminate 100 has a layer structure in which the thermoplastic polyimide layer 10A/non-thermoplastic polyimide layer 20A/thermoplastic polyimide layer 30A/adhesive layer AD/thermoplastic polyimide layer 30B/non-thermoplastic polyimide layer 20B/thermoplastic polyimide layer 10B are laminated in this order.

Here, the thermoplastic polyimide layer 10A constitutes a first insulating resin layer 40A with the non-thermoplastic polyimide layer 20A and the thermoplastic polyimide layer 30A, and the thermoplastic polyimide layer 10B constitutes a second insulating resin layer 40B with the non-thermoplastic polyimide layer 20B and the thermoplastic polyimide layer 30B. Therefore, the laminate 100 has a structure in which the first insulating resin layer 40A, the adhesive layer AD, and the second insulating resin layer 40B are sequentially laminated.

Fig. 2 shows a cross-sectional structure of a laminate 101 according to another preferred embodiment of the present invention. The laminate 101 has a layer structure in which a thermoplastic polyimide layer 10A/a non-thermoplastic polyimide layer 20A/an adhesive layer AD/a non-thermoplastic polyimide layer 20B/a thermoplastic polyimide layer 10B are laminated in this order. Here, the thermoplastic polyimide layer 10A and the non-thermoplastic polyimide layer 20A constitute a first insulating resin layer 40A, and the thermoplastic polyimide layer 10B and the non-thermoplastic polyimide layer 20B constitute a second insulating resin layer 40B. Therefore, the laminate 101 has a structure in which the first insulating resin layer 40A, the adhesive layer AD, and the second insulating resin layer 40B are sequentially laminated.

In the configuration example shown in fig. 1 and 2, the thermoplastic polyimide layer 10A and the thermoplastic polyimide layer 10B as the outermost layers have a function of ensuring adhesion when the metal layers are stacked. The non-thermoplastic polyimide layer 20A and the non-thermoplastic polyimide layer 20B have a function of securing dimensional stability. The plurality of thermoplastic polyimide layers 10A, 10B, 30A, 30B may each include the same or different kinds of thermoplastic polyimide. In addition, the non-thermoplastic polyimide layer 20A and the non-thermoplastic polyimide layer 20B may also include the same or different kinds of non-thermoplastic polyimide. Details of the preferred polyimide used for the first insulating resin layer 40A and the second insulating resin layer 40B will be described later.

In addition, for example, a hardening resin component such as a plasticizer or an epoxy resin, a hardening agent, a hardening accelerator, an organic filler or an inorganic filler, a coupling agent, a flame retardant, or the like may be suitably blended in the first insulating resin layer 40A and the second insulating resin layer 40B.

< Insulating resin layer >

The first insulating resin layer 40A and the second insulating resin layer 40B are not limited to a single layer, and a plurality of resin layers may be stacked. The resin constituting the first insulating resin layer 40A and the second insulating resin layer 40B is not particularly limited as long as it is a resin having electrical insulation properties, and examples thereof include polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, ethylene tetrafluoroethylene (ethylene tetrafluoroethylene, ETFE), and the like, and preferably polyimide is included.

< Adhesive layer >

The adhesive layer AD contains a resin component and a filler component.

Resin composition:

The resin component contains a polyimide (hereinafter sometimes referred to as "adhesive polyimide") having a tetracarboxylic acid residue derived from a tetracarboxylic anhydride component and a diamine residue derived from a diamine component, and contains 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, relative to the total diamine residues. Details of the adhesive polyimide will be described later. The resin component also contains a crosslinking agent described later.

Filler components:

The filler component contains a metal salt of an organic phosphinic acid. The metal salt of the organic phosphinic acid is a flame retardant which does not deteriorate the dielectric characteristics of polyimide. In order to sufficiently exhibit the effect of the present invention, it is preferable that the metal salt of the organic phosphinic acid is 80 wt% or more, more preferably 90 wt% or more, and most preferably 95 wt% to 100 wt% of the filler component. The metal salt of an organic phosphinic acid is preferably, for example, an aluminum salt of an organic phosphinic acid represented by the following general formula (F1).

[ Chemical 1]

In the general formula (F1), two R's independently represent an alkyl group. R is preferably a lower alkyl group having 1 to 4 carbon atoms.

In addition, in the particle size distribution measurement by a laser diffraction-scattering method, the metal salt of an organic phosphinic acid preferably has an average particle diameter (D ₅₀) in the range of 1.0 μm to 3.0 μm, and the proportion of particles having a particle diameter exceeding 10 μm is 1% by volume or less. If the proportion of the particle diameter exceeds 10 μm, the filler particle diameter in the adhesive layer AD becomes large and the filler is liable to fall off during cutting or drilling. As the metal salt of the organic phosphinic acid as described above, commercially available products can be used, and for example Ai Kesuo lit (Exolit) OP945 (trade name, manufactured by Clariant) or the like can be used.

The weight ratio of the filler component to the total amount of 100 parts by weight of the resin components is in the range of more than 40 parts by weight and 90 parts by weight or less, preferably in the range of more than 40 parts by weight and 80 parts by weight or less, more preferably in the range of 45 parts by weight to 70 parts by weight, in terms of ensuring flame retardancy of the adhesive layer AD and exhibiting a tensile modulus of elasticity and a storage modulus of elasticity that can suppress the occurrence of wrinkles at the time of thermocompression bonding with the insulating resin layer. When the weight ratio of the filler component is 40 parts by weight or less, not only the flame retardant effect is not sufficiently exhibited, but also wrinkles are easily generated at the time of thermocompression bonding with the insulating resin layer, and when it exceeds 90 parts by weight, the elongation of the adhesive layer AD may be reduced or the dielectric characteristics may be deteriorated.

In addition, when the concentration of the particulate filler component is increased in order to improve flame retardancy, aggregation occurs, and therefore a large amount of dispersant needs to be blended. However, since the dispersant adversely affects dielectric characteristics, it has been difficult to achieve both low dielectric loss tangent and flame retardancy improvement. In the present invention, as will be described later, in the process of producing the adhesive resin composition, the polyimide and the filler component are mixed in multiple stages, whereby high-concentration blending of the filler component exceeding 40 parts by weight based on 100 parts by weight of the total amount of the resin components is achieved without using a dispersing agent.

In view of sufficiently exhibiting the effect of the present invention, the total amount of the resin component and the filler component is preferably 80 wt% or more, more preferably 90 wt% or more, and most preferably 95 wt% to 100 wt% with respect to the total solid component in the adhesive layer AD. In the present invention, the term "solid component" means the remainder excluding the solvent.

In the adhesive layer AD, the total area ratio of the filler component having a particle diameter of more than 10 μm and the filler-removed portion having a length of more than 10 μm in the area view of 100 μm×100 μm when the cross section in the thickness direction is observed by a scanning electron microscope is preferably 1% or less, more preferably 0.5% or less, and most preferably 0.1% to 0% on the average of the area views of any ten parts. In this case, the term "particle diameter" refers to a long diameter (maximum diameter) when the planar shape in scanning electron microscope observation is other than a perfect circle. In addition, the "filler-removed portion" was observed as a void, which is a trace of removal of a filler component having a particle diameter exceeding 10 μm, in a scanning electron microscope observation of a cross section in the thickness direction, and the length diameter of the void exceeded 10 μm. If the total area ratio of the filler component, which is coarse particles having a particle diameter of more than 10 μm, and the filler falling-off portion having a length of more than 10 μm exceeds 1% on the average, the falling-off of the filler component is liable to occur or has occurred, and thus foreign matter may occur in the circuit processing step or defective through hole plating may occur at the time of drilling and hole opening processing.

The adhesive layer AD preferably has desired characteristics such as low dielectric loss tangent in addition to adhesion. For example, in the case of application to a circuit board, the dielectric loss tangent at 10GHz in the adhesive layer AD is preferably 0.003 or less, more preferably 0.0027 or less, still more preferably 0.0025 or less under a humidity control condition, and preferably 0.007 or less, more preferably 0.006 or less, still more preferably 0.005 or less under a water absorption condition, in order to suppress deterioration of dielectric loss. If the dielectric loss tangent of the adhesive layer AD at 10GHz exceeds 0.003 under humidity control, a problem such as loss of an electrical signal tends to occur in a transmission path of a high-frequency signal when applied to a circuit board. In addition, if the dielectric loss tangent of the adhesive layer AD at 10GHz exceeds 0.007 under the water absorption condition, the adhesive layer AD is easily affected by the ambient humidity, and the transmission loss is easily generated depending on the use environment when applied to the circuit board. The humidity control conditions and the water absorption conditions refer to conditions "humidity control" and "water absorption time" described in examples below.

In addition, for example, in the case of application to a circuit board, the relative dielectric constant of the subsequent layer AD at 10GHz is preferably 4.0 or less in order to secure impedance matching. If the relative dielectric constant of the adhesive layer AD at 10GHz exceeds 4.0, the dielectric loss of the adhesive layer AD deteriorates when applied to a circuit board, and there is a tendency that defects such as loss of an electrical signal occur on a transmission path of a high-frequency signal.

The average thermal expansion coefficient from 250 ℃ to 100 ℃ in the in-plane direction orthogonal to the thickness direction in the subsequent layer AD may exceed 30ppm/K. Since the adhesive layer AD has low elasticity, even if the average thermal expansion coefficient in the in-plane direction exceeds 30ppm/K, the internal stress generated at the time of lamination can be relaxed.

The adhesive layer AD is preferably in the range of 1.0GPa to 1.2GPa, more preferably in the range of 1.0GPa to 1.1GPa, from the viewpoint of effectively suppressing the occurrence of wrinkles when thermally pressed against the insulating resin layer. If the tensile modulus of elasticity of the adhesive layer AD is less than 1.0GPa, wrinkles tend to occur at the time of thermocompression bonding with the insulating resin layer, and if it exceeds 1.2GPa, the adhesion with the insulating resin layer decreases, and air bubbles easily enter between the insulating resin layer and the adhesive layer AD.

Similarly, from the viewpoint of effectively suppressing the occurrence of wrinkles in the thermal compression bonding with the insulating resin layer, the storage modulus of elasticity of the adhesive layer AD at 80 ℃ is preferably in the range of 10MPa to 20MPa, more preferably in the range of 13MPa to 17 MPa. The temperature of 80 ℃ is a temperature at which the thermocompression bonding temperature is assumed, and if the storage modulus of elasticity of the adhesive layer AD at the temperature is less than 10MPa, wrinkles are likely to occur at the time of thermocompression bonding with the insulating resin layer, and if the temperature exceeds 20MPa, the adhesion is reduced.

< Layer thickness >

In the laminate 100 and the laminate 101, when the total thickness of the first insulating resin layer 40A, the adhesive layer AD, and the second insulating resin layer 40B is T1, the total thickness T1 is in the range of 70 μm to 500 μm, preferably in the range of 100 μm to 300 μm. If the total thickness T1 is less than 70 μm, the effect of reducing the transmission loss in the production of the circuit board is insufficient, and if it exceeds 500 μm, productivity may be lowered. In addition, a thickness of 70 μm or more is difficult to achieve in a single layer, but is achieved in the laminate 100 and the laminate 101 by a characteristic laminate structure.

In addition, the thickness T2 of the adhesion layer AD is greater than 50 μm. The effect of the present invention is particularly effectively exhibited in a laminated structure having a low dielectric loss tangent and a large thickness T2 of the adhesive layer AD, while achieving both excellent dielectric characteristics and flame retardancy. From the above point of view, the thickness T2 of the adhesive layer AD is, for example, in the range of more than 50 μm to 450 μm, more preferably in the range of more than 50 μm to 250 μm. If the thickness T2 of the adhesive layer AD is less than the lower limit value, there may be a problem that the low dielectric loss tangent is insufficient and sufficient dielectric characteristics cannot be obtained. On the other hand, if the thickness T2 of the adhesive layer AD exceeds the upper limit value, there may be a problem that it is difficult to secure flame retardancy, a decrease in dimensional stability, and the like.

Further, the effect of the present invention, which is particularly effective in a laminated structure in which the ratio of the thickness T2 of the adhesive layer AD is large, is achieved by combining excellent dielectric characteristics and flame retardancy, and therefore the ratio (T2/T1) of the thickness T2 of the adhesive layer AD to the total thickness T1 is preferably in the range of more than 0.5 to 0.96, more preferably in the range of more than 0.5 to 0.75. When the ratio (T2/T1) is 0.5 or less, the low dielectric loss tangent becomes insufficient, and sufficient dielectric characteristics cannot be obtained. If the amount exceeds 0.96, it is difficult to secure flame retardancy and dimensional stability, and the like may be poor.

The thickness T3 of the first insulating resin layer 40A and the second insulating resin layer 40B is preferably in the range of, for example, 10 μm to 50 μm, more preferably 12 μm to 25 μm, respectively. If the thickness T3 of each of the first insulating resin layer 40A and the second insulating resin layer 40B is less than the lower limit value, warpage of the laminate 100 and the laminate 101 may occur. If the thickness T3 of the first insulating resin layer 40A and the second insulating resin layer 40B exceeds the upper limit value, there may be a problem such as a decrease in the transmission characteristics when the circuit board is manufactured. Further, the first insulating resin layer 40A and the second insulating resin layer 40B may have the same thickness or different thicknesses. The thermoplastic polyimide layers 10A, 10B, 30A, 30B may have the same thickness or different thicknesses, and the non-thermoplastic polyimide layers 20A, 20B may have the same thickness or different thicknesses.

< Dielectric loss tangent >

For example, in the case of application to a circuit board, in order to suppress deterioration of dielectric loss, the dielectric loss tangent at 10GHz measured by using a split column dielectric resonator (split post dielectric resonators, SPDR) in the laminated body 100, 101 is preferably 0.005 or less, more preferably 0.004 or less, still more preferably 0.003 or less under humidity control conditions, and preferably 0.008 or less, more preferably 0.007 or less, still more preferably 0.006 or less under water absorption conditions. If the dielectric loss tangent of the laminate 100 or 101 at 10GHz exceeds 0.005 under humidity control, a loss of an electric signal or the like tends to occur in the transmission path of a high-frequency signal when applied to a circuit board. If the dielectric loss tangent of the laminate 100 or 101 at 10GHz exceeds 0.008 under the water absorption condition, the dielectric loss tends to be affected by the ambient humidity, and the transmission loss tends to occur depending on the use environment when applied to the circuit board. The humidity control conditions and the water absorption conditions refer to conditions "humidity control" and "water absorption time" described in examples below.

< Relative permittivity >

For example, when the laminate 100 and the laminate 101 are applied as insulating layers of circuit boards, the laminate 100 and the laminate 101 preferably have a relative dielectric constant of 3.5 or less at 10GHz measured using SPDR as the insulating layers as a whole, in order to ensure impedance matching. If the relative dielectric constants of the laminate 100 and the laminate 101 at 10GHz exceed 3.5, the dielectric loss of the first insulating resin layer 40A and the second insulating resin layer 40B deteriorates when applied to a circuit board, and thus, defects such as loss of an electrical signal tend to occur in a transmission path of a high-frequency signal.

The laminate 100 and the laminate 101 are preferably long strips having a length L _TD in the width direction (TD direction) of 0.2m or more and 2.0m or less, and a ratio (L _MD/L_TD) of a length L _MD in the longitudinal direction (machine direction, MD direction) to a length L _TD in the width direction (TD direction) of, for example, 25 or more, preferably 50 to 5000. The laminate 100 and the laminate 101 are elongated, and thus can exhibit the effect of suppressing thickness unevenness and wrinkles, which are easily generated when manufactured by a roll-to-roll method or the like, to the maximum extent.

< Polyimide >

Next, polyimide, which is a preferable resin constituting the first insulating resin layer 40A, the second insulating resin layer 40B, and the adhesive layer AD, will be described. The polyimide is obtained by reacting a tetracarboxylic anhydride component with a diamine component comprising an aliphatic diamine and/or an aromatic diamine, and contains a tetracarboxylic acid residue derived from the tetracarboxylic anhydride component and a diamine residue derived from the diamine component. In the present invention, the term "tetracarboxylic acid residue" means a tetravalent group derived from tetracarboxylic dianhydride, and the term "diamine residue" means a divalent group derived from a diamine compound. When the tetracarboxylic dianhydride and the diamine compound as the raw materials are reacted in a substantially equimolar manner, the types and molar ratios of the tetracarboxylic acid residues and the diamine residues contained in the polyimide and the types and molar ratios of the raw materials can be substantially matched.

In the present invention, the term "polyimide" refers to a resin containing a polymer having an imide group in a molecular structure, such as polyamide imide, polyether imide, polyester imide, polysiloxane imide, and polybenzimidazole imide, in addition to polyimide. In addition, when the polyimide has a plurality of structural units, the polyimide may exist in the form of blocks or may exist randomly, but is preferably randomly present.

In the present invention, the term "thermoplastic polyimide" refers to a polyimide having a storage elastic modulus at 30℃of 1.0X10- ⁸ Pa or more and a storage elastic modulus at 300℃of less than 3.0X10- ⁷ Pa, which is measured by a dynamic viscoelasticity measuring device (dynamic thermo-mechanical analyzer (dynamic thermomechanical analyzer, DMA)). The term "non-thermoplastic polyimide" refers to a polyimide that generally does not exhibit softening and adhesion even when heated, and in the present invention, refers to a polyimide having a storage elastic modulus at 30 ℃ of 1.0X10 ⁹ Pa or more and a storage elastic modulus at 300 ℃ of 3.0X10 ⁸ Pa or more, which is measured using a dynamic viscoelasticity measuring Device (DMA).

< Thermoplastic polyimide >

The thermoplastic polyimide used to form the thermoplastic polyimide layers 10A, 10B, 30A, 30B of the first and second insulating resin layers 40A, 40B can be controlled in thermal expansion, adhesion, glass transition temperature, etc. by selecting the types of tetracarboxylic anhydride component and diamine component used as raw materials, or the molar ratio of two or more kinds of anhydrides or diamines. As the tetracarboxylic anhydride component and the diamine component as raw materials, monomers generally used for the synthesis of thermoplastic polyimide can be used, but in order to improve flame retardancy, aromatic tetracarboxylic dianhydride or aromatic diamine is preferably used.

As aromatic tetracarboxylic dianhydrides, for example, pyromellitic dianhydride (pyromellitic dianhydride, PMDA), 3', 4' -benzophenone tetracarboxylic dianhydride (3, 3', 4' -benzophenone tetracarboxylic dianhydride, BTDA), 3',4,4' -diphenylsulfone tetracarboxylic dianhydride (3, 3', 4' -diphenyl sulfone tetracarboxylic dianhydride, DSDA), 4'-oxydiphthalic anhydride (4, 4' -oxydiphthalic dianhydride, ODPA), 4'- (hexafluoroisopropylidene) diphthalic anhydride (4, 4' - (hexafluoroisopropylidene) DIPHTHALIC ANHYDRIDE,6 FDA), 2-bis [4- (3, 4-dicarboxyphenoxy) phenyl ] propane dianhydride (2, 2-bis [4- (3, 4-dicarboxyphenoxy) phenyl ] propane dianhydride, BPADA), p-phenylene bis (trimellitic acid monoester anhydride) (p-PHENYLENE BIS (TRIMELLITIC ACID monoester anhydride), TAHQ), ethylene glycol bis (ethylene glycol bistrimellitic anhydride, TMEG), 2,3,6,7-naphthalene tetracarboxylic dianhydride (2, 3,6,7-NAPHTHALENE TETRACARBOXYLIC DIANHYDRIDE, NTCDA), 3', 4' -biphenyl tetracarboxylic dianhydride (3, 3', 4' -biphenyl tetracarboxylic dianhydride, BPDA), 2,3',3,4' -biphenyl tetracarboxylic dianhydride, 2', 3' -biphenyl tetracarboxylic dianhydride, and the like.

In order to impart sufficient flame retardancy to the laminate 100 and the laminate 101, the thermoplastic polyimide layer 30A and the thermoplastic polyimide layer 30B preferably contain tetracarboxylic acid residues derived from one or more of the aromatic tetracarboxylic dianhydrides in a total of 50 to 100 parts by mole, more preferably 60 to 100 parts by mole, based on 100 parts by mole of all the tetracarboxylic acid residues.

As aromatic diamines, for example, 1, 4-diaminobenzene (p-PDA (p-PHENYLENEDIAMINE, p-phenylenediamine)), 1,3-bis (4-aminophenoxy) benzene (1, 3-bis (4-aminophenoxy) benzone, TPE-R), 1,3-bis (3-aminophenoxy) benzene (1, 3-bis (3-aminophenoxy) benzone, APB), 2-bis [4- (4-aminophenoxy) phenyl ] propane (2, 2-bis [4- (4-aminophenoxy) phenyl ] propane, BAPP), and the like can be preferably used, Bis [4- (4-aminophenoxy) phenyl ] ether (bis [4- (4-aminophenoxy) phenyl ] ether, BAPE), bis [4- (4-aminophenoxy) phenyl ] sulfone (bis [4- (4-aminophenoxy) phenyl ] sulfone, BAPS), bis [4- (4-aminophenoxy) phenyl ] ketone (bis [4- (4-aminophenoxy) phenyl ] ketne, BAPK), bis [4- (3-aminophenoxy) ] biphenyl, bis [4- (4-aminophenoxy) ] biphenyl, 2, 2-bis [4- (4-aminophenoxy) phenyl ] hexafluoropropane, 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenyl ether, 2 '-bis (trifluoromethyl) -4,4' -diaminodiphenyl ether, 1, 3-bis (4-aminophenoxy) benzene, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (3-aminophenoxy) benzene, bisanilinefluorene (bisaniline fluorene, BAFL), 9-bis (4-amino-3-chlorophenyl) fluorene, 9-bis (4-amino-3-methylphenyl) fluorene, 9-bis (4-amino-3-fluorophenyl) fluorene, 4,4' -diamino-p-terphenyl, 2' -dimethyl-4,4' -diaminobiphenyl (2, 2' -dimethyl-4,4' -diaminobiphenyl, m-TB), 2' -diethyl-4,4' -diaminobiphenyl (2, 2' -diethyl-4,4' -diaminobiphenyl, m-EB), 2' -diethoxy-4, 4' -diaminobiphenyl (2, 2' -diethoxyl-4,4' -diaminobiphenyl, m-EOB), 2' -dipropoxy-4,4' -diaminobiphenyl (2, 2' -dipropoxy-4,4' -diaminobiphenyl, m-POB), and, 2,2' -di-n-propyl-4,4' -diaminobiphenyl (2, 2' -di-n-propyl-4,4' -diaminobiphenyl, m-NPB), 2' -divinyl-4,4' -diaminobiphenyl (2, 2' -divinyl-4,4' -diaminobiphenyl, VAB), 4' -diaminobiphenyl, 4' -diamino-2,2' -bis (trifluoromethyl) biphenyl (4, 4' -diamino-2,2' -bis (trifluoromethyl) biphenyl, TFMB), aromatic diamines such as 4,4 '-diamino-2, 2',5 '-tetrachlorobiphenyl and 4,4' -diamino octafluorobiphenyl.

In order to impart sufficient flame retardancy to the laminate 100 and the laminate 101, the thermoplastic polyimide layer 10A, the thermoplastic polyimide layer 10B, the thermoplastic polyimide layer 30A, and the thermoplastic polyimide layer 30B preferably contain one or more diamine residues derived from the aromatic diamine in a total of 50 to 100 parts by mole, more preferably 60 to 100 parts by mole, based on 100 parts by mole of all diamine residues.

< Non-thermoplastic polyimide >

The non-thermoplastic polyimide used to form the non-thermoplastic polyimide layers 20A and 20B in the first insulating resin layer 40A and the second insulating resin layer 40B can be controlled in thermal expansion, dielectric characteristics, and the like by selecting the types of tetracarboxylic anhydride components and diamine components used as raw materials, or the molar ratio of two or more kinds of anhydrides or diamines. As the tetracarboxylic anhydride component and the diamine component as raw materials, monomers generally used in the synthesis of non-thermoplastic polyimide can be used, but in order to improve flame retardancy, aromatic tetracarboxylic dianhydrides or aromatic diamines exemplified in the description of using the thermoplastic polyimide are preferable.

In order to impart sufficient flame retardancy to the laminate 100 and the laminate 101, the non-thermoplastic polyimide layer 20A and the non-thermoplastic polyimide layer 20B preferably contain one or more tetracarboxylic acid residues derived from the aromatic tetracarboxylic dianhydride exemplified in the description of the thermoplastic polyimide in a total of 50 to 100 parts by mol, more preferably 60 to 100 parts by mol, based on 100 parts by mol of all the tetracarboxylic acid residues.

Further, in order to impart sufficient flame retardancy to the laminate 100 and the laminate 101, the non-thermoplastic polyimide layer 20A and the non-thermoplastic polyimide layer 20B preferably contain one or more diamine residues derived from the aromatic diamine exemplified in the description of the thermoplastic polyimide in a total of 50 to 100 parts by mol, more preferably 60 to 100 parts by mol, based on 100 parts by mol of all diamine residues.

< Adhesive polyimide >

The adhesive polyimide is a main component of the resin component contained in the adhesive layer AD. The main component of the resin component means a component contained in an amount exceeding 50% by weight based on the total weight of the resin components. In order to sufficiently exhibit the effect of the present invention, the resin component preferably contains an adhesive polyimide in an amount of preferably 70% by weight or more, more preferably 80% by weight or more, and most preferably 90% by weight or more.

(Tetracarboxylic acid residue)

The adhesive polyimide may include, without particular limitation, tetracarboxylic acid residues derived from tetracarboxylic dianhydrides generally used in thermoplastic polyimides, but preferably contains 90 or more moles of tetracarboxylic acid residues derived from tetracarboxylic dianhydrides represented by the following general formula (1) (hereinafter, sometimes referred to as "tetracarboxylic acid residues (1)") in total, more preferably 95 or more moles, per 100 moles of all the tetracarboxylic acid residues. It is preferable that the tetracarboxylic acid residue (1) is contained in an amount of 90 parts by mole or more in total based on 100 parts by mole of all the tetracarboxylic acid residues, because it is easy to achieve both flexibility and heat resistance of the adhesive polyimide. When the total amount of the tetracarboxylic acid residues (1) is less than 90 parts by mole, the solvent solubility of the adhesive polyimide tends to be low.

[ Chemical 2]

In the general formula (1), X represents a single bond or a divalent group selected from the following formulas.

[ Chemical 3]

-CO-,-SO₂-,-O-,

COO-or COO-Z-OCO-

In the formula, Z represents-C ₆H₄-、-(CH₂) n-or-CH ₂-CH(-O-C(＝O)-CH₃)-CH₂ -, and n represents an integer of 1 to 20.

Examples of the tetracarboxylic dianhydride used for deriving the tetracarboxylic acid residue (1) include: 3,3', 4' -biphenyltetracarboxylic dianhydride (BPDA), 3', 4' -Benzophenone Tetracarboxylic Dianhydride (BTDA), 3',4,4' -diphenylsulfone tetracarboxylic dianhydride (DSDA), 4 '-oxydiphthalic anhydride (ODPA), 4' - (hexafluoroisopropylidene) diphthalic anhydride (6 FDA), 2-bis [ 4- (3, 4-dicarboxyphenoxy) phenyl ] propane dianhydride (BPADA), p-phenylene bis (trimellitic acid monoester anhydride) (TAHQ), ethylene glycol bis trimellitic anhydride (TMEG), and the like.

The adhesive polyimide may contain a tetracarboxylic acid residue derived from an acid dianhydride other than the tetracarboxylic acid dianhydride represented by the general formula (1) in a range that does not impair the effect of the invention. The tetracarboxylic acid residue is not particularly limited, and aromatic tetracarboxylic dianhydrides exemplified in the description of the thermoplastic polyimide are preferably used.

(Diamine residue)

The adhesive polyimide contains 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which two terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups, relative to all diamine residues. When the content of diamine residues derived from the dimer diamine composition is less than 40 mol% relative to all diamine residues, the relative permittivity and dielectric loss tangent tend to increase due to the relative increase of the polar groups contained in the adhesive polyimide, making it difficult to reduce the dielectric loss tangent of the adhesive layer AD, and also failing to obtain the adhesive property required for the adhesive layer AD. By setting the content of diamine residues derived from the dimer diamine composition to 40 mol% or more, the relative dielectric constant and dielectric loss tangent of the adhesive layer AD can be sufficiently reduced, and the adhesive polyimide can be made solvent-soluble. From the viewpoint of the above, the content of diamine residues derived from the dimer diamine composition is preferably 60 mol% or more, more preferably 80 mol% or more, and most preferably in the range of 90 mol% to 100 mol% with respect to all diamine residues.

The dimer diamine composition is a purified product containing the following component (a) as a main component, and the amounts of the component (b) and the component (c) are controlled.

(A) A dimer diamine;

The dimer diamine of component (a) is a diamine in which the two terminal carboxylic acid groups (-COOH) of dimer acid are substituted with primary aminomethyl groups (-CH ₂-NH₂) or amino groups (-NH ₂). Dimer acid is a known dibasic acid obtained by intermolecular polymerization of unsaturated fatty acids, and industrial production processes thereof have been generally standardized in the industry, and can be obtained by dimerization of unsaturated fatty acids having 11 to 22 carbon atoms with a clay catalyst or the like. The industrially available dimer acid is mainly composed of a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linoleic acid, linolenic acid, etc., but contains an arbitrary amount of a monomer acid (having 18 carbon atoms), a trimer acid (having 54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms depending on the degree of purification. In the present invention, the dimer acid is also a compound having reduced unsaturation by further hydrogenation, although double bonds remain after the dimerization reaction. (a) The dimer diamine of the component (a) may be defined as a diamine compound obtained by substituting the terminal carboxylic acid group of a dibasic acid compound having a carbon number in the range of 18 to 54, preferably 22 to 44, with a primary aminomethyl group or an amino group.

The dimer diamine may be characterized by imparting a characteristic of a skeleton derived from dimer acid. That is, since dimer diamine is an aliphatic group of a large molecule having a molecular weight of about 560 to 620, the molar volume of the molecule can be increased and the polar groups of polyimide can be relatively reduced. The characteristic of such dimer diamine is considered to contribute to improvement of dielectric characteristics by reducing the relative permittivity and dielectric loss tangent while suppressing decrease in heat resistance of adhesive polyimide. Further, since the polyimide contains two free mobile hydrophobic chains having 7 to 9 carbon atoms and two chain aliphatic amino groups having a length close to 18 carbon atoms, it is considered that the polyimide can be provided with flexibility and can have an asymmetric chemical structure or a nonplanar chemical structure, and thus the dielectric constant of the polyimide can be reduced.

The dimer diamine composition is preferably one in which the dimer diamine content of the component (a) is increased to 96% by weight or more, preferably 97% by weight or more, more preferably 98% by weight or more by a purification method such as molecular distillation. By setting the dimer diamine content of the component (a) to 96% by weight or more, the molecular weight distribution of the polyimide can be suppressed from expanding. If technically feasible, it is preferable that the entire dimer diamine composition (100 wt%) is composed of the dimer diamine of the component (a).

(B) Monoamine compounds obtained by substituting the terminal carboxylic acid group of monoacid compounds with carbon numbers within the range of 10-40 with primary aminomethyl groups or amino groups;

the monobasic acid compound having a carbon number in the range of 10 to 40 is a mixture of a monobasic unsaturated fatty acid having a carbon number in the range of 10 to 20 derived from a raw material of dimer acid, and a monobasic acid compound having a carbon number in the range of 21 to 40 which is a by-product in the production of dimer acid. Monoamine compounds are compounds obtained by substituting the terminal carboxylic acid group of these monoacid compounds with a primary aminomethyl group or an amino group.

(B) The monoamine compound of the component (a) is a component that suppresses an increase in the molecular weight of polyimide. Upon polymerization of the polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of the polyamic acid or polyimide, thereby sealing the terminal acid anhydride group, thereby suppressing an increase in molecular weight of the polyamic acid or polyimide.

(C) An amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group and a carbon number in the range of 41 to 80 with a primary aminomethyl group or an amino group (excluding the dimer diamine);

The polybasic acid compound having a hydrocarbon group with a carbon number in the range of 41 to 80 is a polybasic acid compound mainly composed of a tribasic acid compound with a carbon number in the range of 41 to 80, which is a by-product in the production of dimer acid. Further, a polymerized fatty acid other than a dimer acid having 41 to 80 carbon atoms may be contained. The amine compound is a compound obtained by substituting the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

(C) The amine compound of the component is a component that promotes an increase in the molecular weight of polyimide. The molecular weight of polyimide is drastically increased by reacting an amino group having three or more functions, which is a main component of a triamine derived from a trimer acid, with a terminal acid anhydride group of a polyamic acid or polyimide. In addition, amine compounds derived from polymerized fatty acids other than dimer acids having 41 to 80 carbon atoms also increase the molecular weight of polyimide, which causes gelation of polyamic acid or polyimide.

In the case of quantifying each component by measurement using gel permeation chromatography (gel permeation chromatography, GPC), in order to easily confirm the peak start point (PEAK START), peak top (peak top), and peak end point (peak end) of each component of the dimer diamine composition, a sample obtained by treating the dimer diamine composition with acetic anhydride and pyridine is used, and cyclohexanone is used as an internal standard substance. The respective components were quantified by the area percentage of the chromatogram of GPC using the samples prepared as described above. The peak start point and the peak end point of each component are set to the minimum value of each peak curve, and the area percentage of the chromatogram can be calculated based on the minimum value.

The dimer diamine composition preferably has a total of component (b) and component (c) of 4% or less, preferably less than 4%, in terms of the area percentage of the chromatogram obtained by GPC measurement. By setting the total of the component (b) and the component (c) to 4% or less, the molecular weight distribution of the polyimide can be suppressed from expanding.

The area percentage of the chromatogram of the component (b) is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. By setting the range, the decrease in molecular weight of the polyimide can be suppressed, and the range of the molar ratio of the tetracarboxylic anhydride component to the diamine component can be widened. The component (b) may not be contained in the dimer diamine composition.

The area percentage of the chromatogram of component (c) is preferably 2% or less, more preferably 1.8% or less, and still more preferably 1.5% or less. By setting the range, a sharp increase in the molecular weight of polyimide can be suppressed, and further, an increase in the dielectric loss tangent of the resin film at a wide frequency can be suppressed. In addition, the component (c) may not be contained in the dimer diamine composition.

When the ratio (b/c) of the area percentages of the chromatograms of the component (b) and the component (c) is 1 or more, the molar ratio of the tetracarboxylic anhydride component to the diamine component (tetracarboxylic anhydride component/diamine component) is preferably 0.97 or more and less than 1.0, and by setting such molar ratio, the molecular weight of the polyimide can be more easily controlled.

When the ratio (b/c) of the area percentages of the chromatograms of the component (b) and the component (c) is less than 1, the molar ratio of the tetracarboxylic anhydride component to the diamine component (tetracarboxylic anhydride component/diamine component) is preferably 0.97 or more and 1.1 or less, and the molecular weight of the polyimide can be more easily controlled by setting such molar ratio.

The dimer diamine composition can be purified by a commercially available product, preferably for the purpose of reducing the content of components other than the dimer diamine of the component (a), and for example, the content of the component (a) is preferably 96% by weight or more. The purification method is not particularly limited, and a known method such as distillation or precipitation purification is preferable. Examples of the commercial products include Pr Li Amin (PRIAMINE) 1073 (trade name) manufactured by Croda Japan (Croda Japan), pr Li Amin (PRIAMINE) 1074 (trade name) manufactured by Croda Japan (Croda Japan), pr Li Amin (PRIAMINE) 1075 (trade name) manufactured by Croda Japan (Croda Japan), and the like.

The adhesive polyimide may also contain diamine residues derived from diamine components other than those described. The diamine residue is not particularly limited, but is preferably a diamine residue derived from an aromatic diamine exemplified in the description of the thermoplastic polyimide.

The adhesive polyimide preferably has a weight average molecular weight (Mw) in the range of 25,000 to 100,000. When the Mw is 25,000 or more, the tear strength and the adhesive strength at the time of film formation can be improved, and the storage stability of the varnish can be improved. When the Mw is less than 25,000, the film becomes brittle, and in the film containing the metal salt of the organic phosphinic acid as the filler component at a high concentration, stress is generated at the interface between the filler and the resin at the time of bending or stretching, and therefore, breakage occurs or voids are generated at the interface between the filler and the resin. On the other hand, when the Mw exceeds 100,000, the viscosity of the varnish increases, and the handleability tends to be lowered. Further, since the Mw tends to be lower in molecular weight and the molecular weight distribution tends to be narrower in the above range, the Mw is more preferably in the range of 50,000 to 100,000, and still more preferably in the range of 50,000 to 70,000.

The imide group concentration of the adhesive polyimide is preferably 22% by weight or less, more preferably 20% by weight or less. The "imide group concentration" herein refers to a value obtained by dividing the molecular weight of the imide group (- (CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself becomes small, and the low hygroscopicity is also deteriorated due to the increase of the polar groups, and Tg and the elastic modulus are increased.

The adhesive polyimide is most preferably a structure after complete imidization. Among them, a part of polyimide may be amic acid. The imidization ratio was calculated from the absorbance of c=o extension and contraction of an imide group-derived c=o of 1780cm ^-1 based on a benzene ring absorber in the vicinity of 1015cm ^-1 by measuring the infrared absorption spectrum of a polyimide film by a fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by japan spectroscopy) and by a primary reflection ATR (attenuated total reflection (attenuated total reflectance)) method.

(Formation of adhesive polyimide by crosslinking)

When the adhesive polyimide has a ketone group, a crosslinking agent having a functional group that reacts with the ketone group in a nucleophilic manner is reacted, whereby a crosslinked structure can be formed. By forming a crosslinked structure, heat resistance can be improved. Such polyimide having a crosslinked structure (hereinafter, sometimes referred to as "crosslinked polyimide") is an application example of adhesive polyimide, and is a preferred form. Further, since the weight average molecular weight varies greatly with the formation of the crosslinking, the adhesive polyimide before the formation of the crosslinking may satisfy the weight average molecular weight.

As the crosslinking agent, for example, an amino compound having at least two primary amino groups as functional groups (hereinafter, sometimes referred to as "crosslinking-forming amino compound") is preferably used. The cross-linked structure can be formed by reacting the ketone group of the adhesive polyimide with the amino group of the cross-linking-forming amino compound to form a c=n bond. That is, the two primary amino groups in the amino compound function as functional groups that undergo nucleophilic reaction with the ketone groups. The primary amino group is particularly advantageous because it does not accompany the formation of a hydroxyl group (-OH) that deteriorates dielectric characteristics.

As the tetracarboxylic dianhydride preferable for forming the adhesive polyimide having a ketone group, for example, 3', 4' -Benzophenone Tetracarboxylic Dianhydride (BTDA) is mentioned, and as the diamine compound, for example, aromatic diamines such as 4,4'-bis (3-aminophenoxy) benzophenone (4, 4' -bis (3-aminophenoxy) benzophenone, BABP), 1,3-bis [4- (3-aminophenoxy) benzoyl ] benzene (1, 3-bis [4- (3-aminophenoxy) benzoyl ] benzene, BABB) and the like are mentioned. In order to form a crosslinked structure, it is particularly preferable to allow an amino compound for forming a crosslinked structure to act on the adhesive polyimide containing preferably 50 mol% or more, more preferably 60 mol% or more of BTDA residues derived from BTDA relative to all tetracarboxylic acid residues. In the present invention, the term "BTDA residue" means a tetravalent group derived from BTDA.

Examples of the amino compound for forming a cross-link include (I) dihydrazide compound, (II) aromatic diamine, and (III) aliphatic amine. Among these, dihydrazide compounds are preferable. Aliphatic amines other than dihydrazide compounds tend to form crosslinked structures even at room temperature, and there is a concern about storage stability of varnishes, while aromatic diamines need to be set at high temperatures in order to form crosslinked structures. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the shortening of the curing time can be achieved. Examples of the dihydrazide compound include dihydrazide compounds such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2, 6-naphthoic acid dihydrazide, 4-bisphenyldihydrazide, 1, 4-naphthoic acid dihydrazide, 2, 6-pyridine dihydrazide, itaconic acid dihydrazide and the like. The dihydrazide compounds mentioned above may be used alone or in combination of two or more.

Further, the amino compound such as (I) dihydrazide compound, (II) aromatic diamine, or (III) aliphatic amine may be used in combination of two or more kinds, for example, as in the combination of (I) and (II), (I) and (III), or (I), and (II) and (III).

In addition, the molecular weight of the amino compound for forming a cross-link used in the present invention (weight average molecular weight in the case where the amino compound for forming a cross-link is an oligomer) is preferably 5,000 or less, more preferably 90 to 2,000, and still more preferably 100 to 1,500, from the viewpoint of making a network structure formed by cross-linking with the amino compound for forming a cross-link more dense. Among them, amino compounds for forming crosslinking having a molecular weight of 100 to 1,000 are particularly preferable. If the molecular weight of the amino compound for crosslinking formation is less than 90, one amino group of the amino compound for crosslinking formation is limited to form a c=n bond with the ketone group of the adhesive polyimide, and the remaining amino group tends to have a bulky surrounding three-dimensional structure, so that the remaining amino group tends to have difficulty in forming a c=n bond.

When the ketone group in the adhesive polyimide is crosslinked with the crosslinking-forming amino compound, the crosslinking-forming amino compound is added to a resin solution containing the adhesive polyimide, and the ketone group in the adhesive polyimide is condensed with the primary amino group of the crosslinking-forming amino compound. The resin solution is cured by the condensation reaction to form a cured product.

The ketone group in the adhesive polyimide is crosslinked by nucleophilic reaction with the functional group of the crosslinking agent, and thus the crosslinked polyimide is a cured product. The conditions for the nucleophilic reaction for the formation of crosslinking are not particularly limited, and may be selected depending on the kind of the crosslinking agent. For example, when a primary amino group of an amino compound for forming a crosslinked structure is reacted with a ketone group in an adhesive polyimide, an imine bond (c=n bond) is formed by a condensation reaction by heating. The conditions for the condensation reaction for the crosslinking formation are not particularly limited as long as the conditions for the formation of the imine bond (c=n bond) between the ketone group in the adhesive polyimide and the primary amino group of the amino compound for crosslinking formation. The temperature of the thermal condensation is preferably in the range of 120 ℃ to 220 ℃, more preferably in the range of 140 ℃ to 200 ℃ for the purpose of discharging water generated by the condensation out of the system or simplifying the condensation step when the thermal condensation reaction is performed subsequently after the synthesis of the adhesive polyimide. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction can be confirmed by measuring the infrared absorption spectrum by using a Fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by Japanese Spectroscopy), and using the decrease or disappearance of the absorption peak derived from the ketone group in the polyimide resin in the vicinity of 1670cm ^-1 and the appearance of the absorption peak derived from the imino group in the vicinity of 1635cm ^-1.

The thermal condensation of the ketone group of the adhesive polyimide with the primary amino group of the amino compound for forming a crosslink can be performed, for example, by the following method:

(1) A method of adding an amino compound for crosslinking formation immediately after synthesis (imidization) of the polyimide and heating;

(2) A method in which an excessive amount of an amino compound is charged in advance as a diamine component, followed by synthesis (imidization) of an adhesive polyimide, and the remaining amino compound which does not participate in imidization or amidation is used as an amino compound for crosslink formation and heated together with the adhesive polyimide;

Or alternatively

(3) A method in which the composition of the adhesive polyimide to which the amino compound for crosslinking formation is added is processed into a predetermined shape (for example, after being applied to an arbitrary substrate or formed into a film shape), and then heated.

For imparting heat resistance to the adhesive polyimide, an example of a crosslinked polyimide having a crosslinked structure formed by an imine bond has been described, but the method is not limited thereto, and as a method for curing polyimide, for example, a compound having an unsaturated bond such as an epoxy resin, an epoxy resin curing agent, maleimide, an activated ester resin, a resin having a styrene skeleton, or the like may be blended and cured.

By using the adhesive polyimide, the adhesive layer AD has excellent flexibility and dielectric characteristics (low dielectric constant and low dielectric loss tangent). In addition, in the adhesive layer AD, in addition to the metal salt of the organic phosphinic acid, a hardening resin component such as a plasticizer or an epoxy resin, a hardening agent, a hardening accelerator, an organic filler or an inorganic filler, a coupling agent, or the like may be suitably blended.

< Synthesis of polyimide >

The thermoplastic polyimide, the non-thermoplastic polyimide, and the adhesive polyimide constituting the adhesive layer AD constituting the first insulating resin layer 40A and the second insulating resin layer 40B can be produced by reacting the tetracarboxylic acid anhydride component and the diamine component in a solvent, and then heating and ring-closing the resultant polyamide acid. For example, a tetracarboxylic anhydride component and a diamine component are dissolved in an organic solvent in approximately equimolar amounts, and the mixture is stirred at a temperature in the range of 0 ℃ to 100 ℃ for 30 minutes to 24 hours to perform polymerization, thereby obtaining a polyamic acid as a precursor of polyimide. In the reaction, the reaction component is dissolved so that the precursor to be produced is in the range of 5 to 50 wt%, preferably 10 to 40 wt%, in the organic solvent. Examples of the organic solvent used in the polymerization reaction include N, N-dimethylformamide (N, N-dimethyl formamide, DMF), N-dimethylacetamide (N, N-DIMETHYL ACETAMIDE, DMAc), N-diethylacetamide, N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP), 2-butanone, dimethylsulfoxide (dimethyl sulfoxide, DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and cresol. These solvents may be used in combination of two or more kinds, and further, aromatic hydrocarbons such as xylene and toluene may be used in combination. The amount of the organic solvent used is not particularly limited, and is preferably adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight.

The synthesized polyamic acid is generally advantageously used as a reaction solvent solution, but may be concentrated, diluted, or replaced with other organic solvents as necessary. In addition, polyamide acid generally has excellent solvent solubility, so can be advantageously used. The viscosity of the solution of polyamic acid is preferably in the range of 500 mPas to 100,000 mPas. When the thickness is outside the above range, defects such as uneven thickness and streaks are likely to occur in the film when the coating operation is performed by a coater or the like.

The method for imidizing the polyamic acid to form the adhesive polyimide is not particularly limited, and a heat treatment that takes 1 to 24 hours to heat under a temperature condition in the range of 80 to 400 ℃, for example, may be preferably employed.

[ Metal-clad laminate ]

The metal-clad laminate of the present invention comprises the laminate and metal layers laminated on one or both sides of the laminate.

Fig. 3 shows a cross-sectional structure of a metal-clad laminate 200 according to a preferred embodiment of the present invention. The metal-clad laminate 200 has a structure in which metal layers 110A and 110B are laminated on both sides of a laminate 100. Therefore, the metal-clad laminate 200 has a structure in which the metal layer 110A/the first insulating resin layer 40A/the adhesive layer AD/the second insulating resin layer 40B/the metal layer 110B are sequentially laminated. The metal layers 110A and 110B are located outermost, and the first insulating resin layer 40A and the second insulating resin layer 40B are disposed inside the metal layers, and the adhesive layer AD is disposed between the first insulating resin layer 40A and the second insulating resin layer 40B. The metal-clad laminate 200 having such a layer structure may be considered to have a structure in which a first single-sided metal-clad laminate (C1) obtained by stacking the metal layer 110A, the thermoplastic polyimide layer 10A, the non-thermoplastic polyimide layer 20A, and the thermoplastic polyimide layer 30A in this order, and a second single-sided metal-clad laminate (C2) obtained by stacking the metal layer 110B, the thermoplastic polyimide layer 10B, the non-thermoplastic polyimide layer 20B, and the thermoplastic polyimide layer 30B in this order are bonded to each other with the adhesive layer AD facing each other with the insulating resin layer side.

As shown in fig. 4, a metal-clad laminate 201 having a structure in which a metal layer 110A and a metal layer 110B are laminated on both sides of a laminate 101 may be used instead of the laminate 100. The metal-clad laminate 201 has a structure in which a metal layer 110A, a first insulating resin layer 40A, an adhesive layer AD, a second insulating resin layer 40B, and a metal layer 110B are laminated in this order. In this case, the metal-clad laminate 201 may be constructed such that a first single-sided metal-clad laminate (C1) obtained by stacking the metal layer 110A, the thermoplastic polyimide layer 10A, and the non-thermoplastic polyimide layer 20A in this order and a second single-sided metal-clad laminate (C2) obtained by stacking the metal layer 110B, the thermoplastic polyimide layer 10B, and the non-thermoplastic polyimide layer 20B in this order are bonded to each other with the adhesive layer AD facing each other on the insulating resin layer side.

In fig. 3 and 4, the metal-clad laminate is illustrated with metal layers on both sides of the laminate 100 and the laminate 101, but the metal-clad laminate may be a single-sided metal-clad laminate with metal layers on one side of the laminate 100 and the laminate 101.

(Metal layer)

The material of the metal layer 110A and the metal layer 110B is not particularly limited, and examples thereof include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof. Among them, copper or copper alloy is particularly preferable. The wiring layer in the circuit board according to the present embodiment described later is also made of the same material as the metal layer 110A and the metal layer 110B.

The thickness of the metal layers 110A and 110B is not particularly limited, and in the case of using a metal foil such as a copper foil, it is preferable that the thickness is 35 μm or less, and more preferably in the range of 5 μm to 25 μm. The lower limit of the thickness of the metal foil is preferably set to 5 μm from the viewpoint of production stability and operability. In the case of using a copper foil, the copper foil may be a rolled copper foil or an electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

For example, the metal foil may be subjected to surface treatment with a wallboard (siding), an aluminum alkoxide, an aluminum chelate compound, a silane coupling agent, or the like for the purpose of rust prevention treatment or improvement of adhesion.

[ Production of Metal-clad laminate ]

The metal-clad laminate 200 and the metal-clad laminate 201 can be manufactured by, for example, the following method 1 or method 2. The adhesive polyimide forming the adhesive layer AD may be crosslinked as described above.

[ Method 1]

First, a first single-sided metal-clad laminate (C1) and a second single-sided metal-clad laminate (C2) having the above-described layer structure are prepared. Next, a solution containing the adhesive polyimide and a filler component is formed into a sheet to prepare an adhesive film as the adhesive layer AD. The adhesive film is arranged between and bonded to the first insulating resin layer 40A of the first single-sided metal-clad laminate (C1) and the second insulating resin layer 40B of the second single-sided metal-clad laminate (C2), and thermocompression bonding is performed.

[ Method 2]

First, a first single-sided metal-clad laminate (C1) and a second single-sided metal-clad laminate (C2) are prepared. Next, the adhesive resin composition forming the adhesive layer AD is applied to either or both of the first insulating resin layer 40A of the first single-sided metal-clad laminate (C1) and the second insulating resin layer 40B of the second single-sided metal-clad laminate (C2) at a predetermined thickness, and dried to form a coating film. Then, the first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) are bonded to each other on the side of the coating film, and thermocompression bonding is performed.

The first single-sided metal-clad laminate (C1) and the second single-sided metal-clad laminate (C2) used in the method 1 and the method 2 can be produced, for example, by repeatedly applying a solution of polyamic acid, which is a precursor of thermoplastic polyimide or non-thermoplastic polyimide, sequentially to metal foils serving as the metal layers 110A and 110B, drying the same, and performing heat treatment to imidize the same.

The adhesive film used in the method 1 can be produced, for example, by applying a solution containing the adhesive polyimide, a filler component and an organic solvent (sometimes referred to as an "adhesive resin composition" in the present specification) on a support substrate, drying the solution, and then peeling the dried solution from the support substrate to produce the adhesive film. The adhesive film and the adhesive resin composition are also one of preferred embodiments of the present invention.

In the above, the method of applying the polyamic acid solution or the adhesive resin composition to a metal foil, a support substrate, an insulating resin layer, or the like is not particularly limited, and the application may be performed by, for example, a coater such as a corner wheel, a die, a knife, or a die lip.

The laminate 100 and the laminate 101 of the present embodiment obtained as described above can be subjected to wiring circuit processing by etching the metal layer 110A and/or the metal layer 110B, for example, to manufacture a circuit board such as a single-sided FPC or a double-sided FPC.

[ Adhesive resin composition ]

Next, the adhesive resin composition according to the embodiment of the present invention will be described. Since the adhesive polyimide is solvent-soluble, it can be used in the form of a composition containing an organic solvent, and is preferably used as an adhesive resin composition containing a resin component, a filler component and an organic solvent. The content of the resin component and the filler component is as described above. The adhesive resin composition has a tensile elastic modulus in the range of 1.0GPa to 1.2GPa when formed into a film at a thickness in the range of more than 50 μm and 450 μm, and a storage elastic modulus at 80 ℃ in the range of 10MPa to 20 MPa. The film is the same as the adhesive film described below.

In the adhesive resin composition, the weight ratio of the filler component to the total 100 parts by weight of the resin components is in the range of more than 40 parts by weight and 90 parts by weight or less, preferably in the range of more than 40 parts by weight and 80 parts by weight or less, more preferably in the range of 45 parts by weight to 70 parts by weight, in terms of ensuring flame retardancy of the adhesive layer AD and exhibiting a tensile modulus of elasticity and a storage modulus of elasticity that can suppress the occurrence of wrinkles at the time of thermocompression bonding with the insulating resin layer. If the weight ratio of the filler component is less than 40 parts by weight, not only the flame retardant effect is not sufficiently exhibited, but also wrinkles are easily generated at the time of thermocompression bonding with the insulating resin layer, and if it exceeds 90 parts by weight, the elongation at the time of forming the adhesive layer AD or the adhesive film may be reduced, or the dielectric characteristics may be deteriorated. In view of sufficiently exhibiting the effect of the present invention, the total amount of the resin component and the filler component is preferably 80 wt% or more, more preferably 90 wt% or more, and most preferably 95 wt% to 100 wt% based on the total solid component in the adhesive resin composition.

The organic solvent is not particularly limited as long as it is soluble in the adhesive polyimide, and examples thereof include N, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, methylcyclohexanone, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, methanol, ethanol, benzyl alcohol, cresol, acetone, and the like. These organic solvents may be used in combination of two or more kinds, and further aromatic hydrocarbons such as xylene and toluene may be used in combination.

In the case of using an adhesive polyimide having a ketone group in the molecule as a resin component, the adhesive resin composition further preferably contains, as an optional component, a crosslinking agent having a functional group that reacts with the ketone group in a nucleophilic manner. Here, the content of the adhesive polyimide having a ketone group in the molecule and the crosslinking agent is as described above. The adhesive resin composition preferably contains a crosslinking agent such that the total of the functional groups of the crosslinking agent is in the range of 0.04 mol to 0.50 mol, preferably in the range of 0.06 mol to 0.40 mol, relative to 1 mol of ketone groups contained in the adhesive polyimide. For example, when an amino compound for forming a cross-linking is used as the cross-linking agent, the primary amino groups may be contained in a total amount of 0.04 to 0.50 mol, preferably 0.06 to 0.40 mol, based on 1 mol of the ketone groups. If the total of the functional groups of the crosslinking agent is less than 0.04 mol based on 1 mol of the ketone group, the crosslinking formation cannot be sufficiently performed, and therefore, the heat resistance after curing tends to be hardly exhibited. On the other hand, if the amount exceeds 0.5 mol, the dielectric loss tangent tends to be increased. This is presumably because the mobility of polyimide molecular chains is limited by an excessive amount of the crosslinking agent, and the formation of a regular structure of molecular chains that effectively suppresses dielectric loss tangent upon hardening is hindered. If the amount of the crosslinking agent is too large, the unreacted crosslinking agent acts as a thermoplastic agent, and the heat resistance tends to be lowered when the adhesive layer AD is formed.

The viscosity of the adhesive resin composition is not particularly limited as long as it is a viscosity at which coating is possible, and is preferably in the range of 500mpa·s to 100000mpa·s, more preferably in the range of 1000mpa·s to 5000mpa·s. When the thickness is outside the above range, defects such as uneven thickness and streaks are likely to occur in the adhesive film during the coating operation. The solid content concentration in the adhesive resin composition is preferably in the range of 30wt% to 40 wt%, more preferably in the range of 33 wt% to 37 wt%.

The adhesive resin composition may be suitably blended with, for example, other curing resin components such as plasticizers and epoxy resins, curing agents, curing accelerators, organic fillers other than metal salts of organic phosphinic acids, inorganic fillers, coupling agents, dispersants, and the like as optional components within a range that does not impair the effects of the invention.

The adhesive resin composition can be produced by a method comprising the following steps (i) and (ii);

(i) A step of mixing and stirring a part of the resin component and the filler component in an organic solvent to obtain a filler dispersion;

And

(Ii) The step of mixing the remaining part of the resin component with the organic solvent into the filler dispersion and stirring the mixture to obtain the adhesive resin composition.

In the step (i), the weight ratio of the resin component in the filler dispersion is set to be in the range of 3 to 15 parts by weight with respect to 100 parts by weight of the final total amount of the resin component, and the solid content concentration in the filler dispersion is adjusted to be in the range of 40 to 60% by weight. When the weight ratio of the resin component in the filler dispersion obtained in the step (i) is less than 3 parts by weight relative to 100 parts by weight of the final total amount of the resin components, or when the solid content concentration exceeds 60% by weight, uniform dispersion of the filler component becomes difficult and aggregation occurs. On the other hand, when the weight ratio of the resin component in the filler dispersion obtained in the step (i) exceeds 15 parts by weight relative to 100 parts by weight of the final total amount of the resin component, or when the solid content concentration is less than 40% by weight, it is difficult to prepare the filler component in the step (ii) at a high concentration exceeding 40 parts by weight.

In the step (ii), the weight ratio of the filler component in the adhesive resin composition is adjusted to be in the range of more than 40 parts by weight and 90 parts by weight or less relative to 100 parts by weight of the final total amount of the resin components, and the solid content concentration in the adhesive resin composition is adjusted to be in the range of 30 to 40% by weight.

The organic solvent used in the steps (i) and (ii) may be the same as the organic solvent described for the adhesive resin composition.

According to the production method of the present embodiment, by blending the resin component in multiple stages and adjusting the solid content concentration, aggregation is not generated without blending the dispersant, and high concentration blending of the filler component exceeding 40 parts by weight with respect to 100 parts by weight of the final total amount of the resin component can be performed, and when the adhesive layer AD or the adhesive film is formed, both low dielectric loss tangent and flame retardancy are achieved. The adhesive resin composition obtained by the production method of the present embodiment does not require a dispersant, and therefore may contain substantially no dispersant. Among these, the dispersant is not hindered from being blended in a range that does not greatly affect the dielectric characteristics. The term "substantially does not contain a dispersant" means, for example, an amount of 1.0 parts by weight or less and preferably 0.1 parts by weight or less relative to 1.0 parts by weight or less, which is the minimum dispersing amount required for satisfactorily dispersing 100 parts by weight of the filler component.

[ Adhesive film ]

Next, an adhesive film according to an embodiment of the present invention will be described. The adhesive film can be produced by coating the adhesive resin composition on an arbitrary substrate, drying the same, and then peeling the same. The adhesive film contains a resin component and a filler component, and the composition of each component is the same as that of the adhesive layer AD, and the weight ratio of the filler component in the adhesive film to the total amount of the resin components of 100 parts by weight is in the range of more than 40 parts by weight and 90 parts by weight or less. In view of sufficiently exhibiting the effect of the present invention, the total amount of the resin component and the filler component is preferably 80 wt% or more, more preferably 90 wt% or more, and most preferably 95 wt% to 100 wt% with respect to the total solid component in the adhesive film. The thickness of the adhesive film is preferably the same as the thickness of the adhesive layer AD in the laminate 100 and the laminate 101, and the tensile modulus of elasticity, the storage modulus of elasticity, and the dielectric loss tangent and the relative dielectric constant under humidity control of the adhesive film are preferably the same as those of the adhesive layer AD. Further, in a surface field of 100 μm×100 μm when the adhesive film is observed in a cross section in a thickness direction of the adhesive film, a total area ratio of a filler component having a particle diameter exceeding 10 μm and a filler-removed portion having a length exceeding 10 μm is preferably 1% or less, more preferably 0.5% or less, and most preferably 0.1% -0% based on an average value of the surface field of any ten portions. In this case, the meaning of "particle diameter" and "filler-removed portion" is as described in the following layer AD.

[ Circuit Board ]

The metal-clad laminate 200 and the metal-clad laminate 201 of the present embodiment are mainly effective as circuit board materials for FPCs, rigid-flexible circuit boards, and the like. That is, the wiring layers are formed by patterning one or both of the two metal layers 110A and 110B of the metal-clad laminate 200 and the metal-clad laminate 201 according to the present embodiment by a conventional method, whereby a circuit board such as an FPC according to an embodiment of the present invention can be manufactured.

[ Electronic component, electronic device ]

The electronic component and the electronic device according to the present embodiment include the circuit board. Examples of the electronic component of the present embodiment include a liquid crystal display, an organic Electroluminescence (EL) display, a display device such as electronic paper, organic EL lighting, a solar cell, a touch panel, a camera module, an inverter, a converter, and a structural member thereof. Examples of the electronic device include an HDD, a DVD, a mobile phone, a smart phone, a tablet terminal, an electronic control unit (electronic control unit, ECU) of an automobile, a power control unit (power control unit, PCU), and the like. The circuit board is preferably used as a component such as a wiring of a movable portion, a cable, or a connector in these electronic components or electronic devices.

Examples (example)

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, various measurements and evaluations were as follows.

[ Measurement of viscosity ]

The viscosity at 25℃was measured using an E-type viscometer (trade name: DV-II+Pro, manufactured by Brookfield Co.). The rotational speed was set so that the torque became 10% to 90%, and after 2 minutes passed since the start of measurement, the value at which the viscosity was stable was read.

[ Measurement of weight average molecular weight (Mw) ]

The weight average molecular weight was measured by means of a gel permeation chromatograph (manufactured by Tosoh Co., ltd., trade name: HLC-8220 GPC). Polystyrene was used as a standard substance, and tetrahydrofuran (Tetrahydrofuran, THF) was used as a developing solvent.

[ Measurement of relative permittivity (Dk) and dielectric loss tangent (Df) ]

The relative dielectric constants and dielectric loss tangents of the resin sheets "conditioned" and "absorbed water" at 10GHz were measured using a vector network analyzer (manufactured by Agilent, trade name E8363C) and an SPDR resonator. The humidity is controlled by placing the mixture for 24 hours at the temperature of 24-26 ℃ and the humidity of 45-55%RH, and the humidity is controlled by immersing the mixture in pure water for 48 hours at the time of water absorption, and then measuring the mixture at the temperature of 24-26 ℃ and the humidity of 45-55%RH.

[ Measurement of coefficient of thermal expansion (coefficient of thermal expansion, CTE) ]

The adhesive sheet peeled from the single-sided metal-clad laminate or the release substrate was cut into a size of 3mm×20mm, and an average thermal expansion coefficient (thermal expansion coefficient) from 10 ℃ to 20 ℃ was obtained by heating the sheet to 50 ℃ at a constant temperature-rising rate while applying a load of 5.0g using a thermo-mechanical analyzer (trade name: TMA7100, manufactured by Hitachi high-tech science (HITACHI HIGH-TECH SCIENCE)). The polyimide film was cut to the same size, and the polyimide film was heated from 30 to 265 ℃ at a constant temperature rise rate while applying a load of 5.0g, and was further held at that temperature for 10 minutes, and then cooled at a rate of 5 ℃ per minute, whereby the average thermal expansion coefficient (thermal expansion coefficient) from 250 to 100 ℃ was obtained.

[ Measurement of storage modulus of elasticity and glass transition temperature (Tg) ]

For the storage modulus of elasticity, an adhesive sheet peeled from a single-sided metal-clad laminate or a release substrate was cut into a size of 5mm×20mm, and a dynamic viscoelasticity device (manufactured by DMA: TA instruments (TA instruments) under the trade name RSA-G2) was used, and the storage modulus of elasticity at 80 ℃ was measured as a lamination temperature by stepwise heating at a temperature rise rate of 4 ℃ per minute from 30 ℃ to 100 ℃. The polyimide film was cut into the same size, and was subjected to stepwise heating at a temperature rising rate of 4℃per minute from 30℃to 400℃and measured at a frequency of 11Hz, and the maximum temperature at which the value of Tan. Delta. In the measurement was maximum was defined as Tg. Polyimide having a storage elastic modulus at 30 ℃ of 1.0X10 ⁸ Pa or more and a storage elastic modulus at 300 ℃ of less than 3.0X10 ⁷ Pa is judged to be "thermoplastic", and polyimide having a storage elastic modulus at 30 ℃ of 1.0X10 ⁹ Pa or more and a storage elastic modulus at 300 ℃ of 3.0X10 ⁸ Pa or more is judged to be "non-thermoplastic".

[ Measurement of tensile Strength, tensile elongation and tensile elastic coefficient ]

The tensile strength, tensile elongation and tensile modulus of elasticity were measured at a temperature of 23℃and a relative humidity of 50% using Storgaku (Stroggraph) R-1 manufactured by Toyo Seiki. For the sample for measurement, the adhesive sheet peeled from the single-sided metal-clad laminate or the release substrate was cut into a size of MD:250mm X TD:12.7mm, and the measurement was performed under conditions of a load cell: 500N, a stretching speed: 50 mm/min, and an inter-chuck distance: 50 mm. The tensile strength is a stress value calculated by dividing the load at the time of breaking the sample by the cross-sectional area, and the tensile elongation is a value obtained by dividing the strain at the time of breaking the sample by the length of the sample in the MD direction. The tensile elastic modulus was calculated by the least square method from the interval where the strain was 0.05% to 0.5%.

[ Measurement of particle diameter of filler to be used ]

The particle diameter was measured by a laser diffraction-scattering measurement method using a laser diffraction type particle size distribution measuring apparatus (trade name: laser particle Sizer (Master Sizer) 3000 manufactured by Malvern) and using 2-propanol as a dispersion medium under the condition that the refractive index of the particles was 1.50.

[ Evaluation of flame retardancy ]

The flame retardancy was measured by the following procedure. The metal-clad laminate was subjected to etching with an aqueous solution of ferric chloride to remove copper foil to obtain a film, which was used as a flame retardancy evaluation sample (width 50 mm. Times. Length 180 mm). For the flame retardancy evaluation sample, the burning time after the first flame release was measured according to the thin material vertical test method of the UL94VTM test (t 1). The probability that the number of samples of 10 combustion times (t 1) was less than 10 seconds and more than 80% was defined as "good" and the probability that the number of samples was less than 80% was defined as "bad".

[ Evaluation of uneven thickness ]

The thickness unevenness was measured by the following procedure. The adhesive sheet peeled from the single-sided metal-clad laminate or the release substrate was measured in the TD direction with a contact digital film thickness meter (Di Ji Ku Ji (DIGIMICRO) MH-15) manufactured by Nikon (Nikon) Co., ltd.) at 1mm intervals, and the average thickness of the portion except the end 30mm was calculated. The absolute values of the differences between the thicknesses of the measurement points except for 30mm at the end and the average thickness were summed up, divided by the number of measurement point points, and the obtained values were regarded as thickness unevenness.

[ Evaluation of wrinkles and adhesion ]

Regarding evaluation of wrinkles, the laminated double-sided copper-clad laminate was visually observed to confirm the presence or absence of step-like wrinkles caused by deformation or folding of the adhesive sheet. Further, the single-sided copper-clad laminate was peeled from the laminated double-sided copper-clad laminate, and the surface of the adhesive sheet was visually observed to confirm whether or not there was a change in color tone caused by deformation or folding of the adhesive sheet.

[ Evaluation of Filler Fall-off Property and coarse particle ratio ]

For evaluation of filler falling-off property, a sample obtained by cutting an adhesive sheet into a size of MD:10mm×TD:2mm was used, and after cutting the cut surface in the thickness direction from above 90 degrees with respect to the plane of the sample by a small microtome (manufactured by Jieshi engineering (Jasco Engineering) Co., HW-1) equipped with a single blade Razor (manufactured by FEATHER SAFETY Razor) Co., ltd., the cut surface was observed with a scanning electron microscope (manufactured by Hitachi Co., ltd., S-4700) at an acceleration voltage of 5.0kV, the presence or absence of voids in the section of the adhesive layer was confirmed.

In addition, in observation of a cut surface in the thickness direction of a sample by the scanning electron microscope (manufactured by Hitachi Ltd., S-4700), the area ratio of the total of coarse filler particles having a particle diameter of more than 10 μm and filler-removed parts having a length of more than 10 μm in a surface field of 100 μm×100 μm was measured, and the average value of the surface field of any ten parts was obtained, thereby calculating the coarse particle ratio.

Abbreviations used in this example refer to the following compounds.

BPDA 3,3', 4' -Biphenyltetracarboxylic dianhydride

PMDA pyromellitic dianhydride

M-TB 2,2 '-dimethyl-4, 4' -diaminobiphenyl

BAPP 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane

TPE-R1, 3-bis (4-aminophenoxy) benzene

BTDA 3,3', 4' -benzophenone tetracarboxylic dianhydride

DDA is a mixture of aliphatic diamines having 36 carbon atoms (manufactured by Croda Japan, inc. trade name: pr Li Amin (PRIAMINE) 1074, distilled and refined, amine value: 210mgKOH/g, dimer diamine of cyclic structure and chain structure, component (a) 97.9%, component (b) 0.3%, component (c) 1.8%

The "%" of the components (a), (b) and (c) refer to the area percentage of the chromatogram in the GPC measurement. The molecular weight of DDA is calculated by the following formula.

Molecular weight=56.1×2×1000/amine number ]

NMP N-methyl-2-pyrrolidone

DMAc, N-dimethylacetamide

N-12 dodecanedioic acid dihydrazide

OP945 organic aluminum phosphinate (trade name: ai Kesuo Lite (Exolit) OP945, D ₅₀：2.1μm,D₉₅: 3.0 μm, maximum particle diameter: 6.7 μm, proportion of particle diameter exceeding 10 μm: 0% by volume, manufactured by Clariant Japan Co., ltd.)

OP935 organic aluminum phosphinate (trade name: ai Kesuo Lite (Exolit) OP935, D ₅₀：2.7μm,D₉₅: 6.8 μm, maximum particle size: 11.5 μm, ratio of particle size exceeding 10 μm: 1.07% by volume, manufactured by Clariant Japan Co., ltd.)

Synthesis example 1

< Preparation of resin solution for adhesive layer >

Under a nitrogen stream, 45.43 parts by weight of BTDA (0.1410 parts by mole), 74.57 parts by weight of DDA (0.1396 parts by mole), 168 parts by weight of NMP and 112 parts by weight of xylene were charged into a reaction tank, and thoroughly mixed at 40 ℃ for 1 hour to prepare a polyamic acid solution. The polyamic acid solution was heated to 190℃and stirred for 5 hours, and 98 parts by weight of xylene was added to prepare an imidized polyimide solution 1 (solid content: 30% by weight, weight average molecular weight: 52,800).

Synthesis example 2

< Preparation of polyamic acid solution for insulating resin layer >

78.36 Parts by weight of m-TB (0.3691 parts by weight) and 7.97 parts by weight of BAPP (0.0194 parts by weight) and DMAc in an amount of 15% by weight of solid content concentration after polymerization were charged into the reaction vessel under a nitrogen stream, and stirred and dissolved at room temperature. Then, 50.10 parts by weight of PMDA (0.2297 parts by weight) and 45.05 parts by weight of BPDA (0.1531 parts by weight) were added, followed by continuing stirring at room temperature for 3 hours to carry out polymerization, thereby producing a polyamic acid solution 1 (viscosity: 28,900 mPas). The storage modulus of elasticity of a polyimide film obtained by applying the polyamic acid solution 1 to a substrate, drying it and imidizing it was measured and found to be "non-thermoplastic".

Synthesis example 3

< Preparation of polyamic acid solution for insulating resin layer >

Polyamide acid solution 2 (viscosity: 2,650 mPas) was prepared in the same manner as in Synthesis example 2 except that 3.48 parts by weight of m-TB (0.0164 parts by mole), 27.14 parts by weight of TPE-R (0.0928 parts by mole) and DMAc in an amount of 12% by weight in solid content concentration after polymerization were charged, and 9.72 parts by weight of PMDA (0.0446 parts by mole) and 19.66 parts by weight of BPDA (0.0668 parts by mole) were used as raw materials. The storage modulus of elasticity of a polyimide film obtained by applying the polyamic acid solution 2 to a substrate, drying it and imidizing it was measured and the result was "thermoplastic".

< Preparation of resin varnish for adhesive layer >

(Formulation example 1)

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 131.11 parts by weight of OP945 (48.28 parts by weight relative to 100 parts by weight of the total of the final resin components), 120.33 parts by weight of xylene, and 21.00 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 19.33 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 1 (viscosity: 2,910mpa·s).

(Blending example 2)

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 157.33 parts by weight of OP945 (57.94 parts by weight relative to 100 parts by weight of the total of the final resin components), 128.67 parts by weight of xylene, and 22.00 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 16.67 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 2 (viscosity: 3,150 mPa.s).

Preparation example 3

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 183.56 parts by weight of OP945 (67.59 parts by weight relative to 100 parts by weight of the total of the final resin components), 137.00 parts by weight of xylene, and 23.00 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 15.00 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 3 (viscosity: 3,320 mPa.s).

Preparation example 4

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 65.56 parts by weight of OP945 (24.14 parts by weight based on 100 parts by weight of the total of the final resin components), 95.33 parts by weight of xylene, and 18.33 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 26.67 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 4 (viscosity: 2,230 mPa.s).

Preparation example 5

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 91.78 parts by weight of OP945 (33.80 parts by weight based on 100 parts by weight of the total of the final resin components), 103.67 parts by weight of xylene, and 19.00 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 24.00 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 5 (viscosity: 2,450 mPa.s).

Preparation example 6

9.47 Parts by weight of N-12 was blended into 100.00 parts by weight of polyimide solution 1, and 104.89 parts by weight of OP945 (38.62 parts by weight relative to 100 parts by weight of the total of the final resin components), 112.00 parts by weight of xylene, and 20.00 parts by weight of NMP were added and diluted, and stirred by a rotation/revolution mixer. Thereafter, 773.67 parts by weight of polyimide solution 1 and 21.67 parts by weight of xylene were added and stirred for 2 hours to prepare an adhesive composition 6 (viscosity: 2,690mpa·s).

(Blending example 7)

To 873.67 parts by weight of polyimide solution 1, 145.33 parts by weight of xylene and 22.00 parts by weight of NMP were added and diluted, 9.47 parts by weight of N-12 and 157.33 parts by weight of OP935 (57.94 parts by weight relative to 100 parts by weight of the total of the final resin components) were prepared, and then the mixture was stirred for 2 hours to prepare adhesive composition 7 (viscosity: 3,030 mPa.s).

Production example 1

< Preparation of Single-sided Metal-clad laminate sheet 1 >

On a long copper foil 1 (electrolytic copper foil, thickness: 12 μm, surface roughness Rz on the resin layer side: 0.6 μm, width: 0.5 μm), a polyamic acid solution 2 was uniformly applied using a corner-wheel coater so that the thickness after curing was about 2 μm to 3 μm, and then heated and dried at 145 ℃ to remove the solvent. Then, the polyamic acid solution 1 is uniformly applied to a thickness of about 14 to 16 μm after curing, and the solution is dried by heating at 80 to 145 ℃. Further, the polyamic acid solution 2 was uniformly applied so that the thickness after curing was about 2 μm to 3 μm, and then heated and dried at 145 ℃ to remove the solvent. Further, the imidization was completed by performing a stepwise heat treatment from 120 ℃ to 360 ℃, thereby producing an elongated single-sided metal clad laminate 1 having a polyimide layer thickness of 20 μm.

< Preparation of polyimide film 1 >

The copper foil layer of the single-sided metal clad laminate 1 was removed by etching using an aqueous solution of ferric chloride to prepare a polyimide film 1 having a thickness of 20 μm. CTE was 20ppm/K, dk and Df for conditioning were 3.40 and 0.0033, respectively, and Dk and Df for water absorption were 3.40 and 0.0070, respectively. Further, the storage elastic coefficients at Tg of 290℃and 30℃and 125℃were 8.9X10 ⁹Pa、5.9×10⁹ Pa, respectively.

Example 1

The adhesive composition 1 prepared in formulation example 1 was continuously and uniformly applied to the insulating resin layer side surface of the long single-sided metal-clad laminate 1 using a die coater so that the thickness after drying was 60 μm, and then, the single-sided metal-clad laminate 1a' with an adhesive layer was obtained by stepwise heat drying from 80 ℃ to 160 ℃. The adhesive layer was peeled off from the single-sided metal-clad laminate 1a' with the adhesive layer to obtain an adhesive sheet 1. The adhesive sheet 1 had a tensile elastic modulus of 1.07GPa, a tensile elongation of 183%, a tensile strength of 24MPa, a storage elastic modulus at 80℃of 12.1MPa, a CTE of 111ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0023, respectively, and a thickness unevenness of 0.77. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, the surface of the single-sided metal-clad laminate 1a' with the adhesive layer on the adhesive layer side was placed in contact with the surface of the other single-sided metal-clad laminate 1 on the insulating resin layer side, and while conveying them via guide rollers, a double-sided copper-clad laminate 1 was obtained by continuously performing thermal compression bonding while continuously overlapping with a heating and pressing device having at least one pair of metal heating and pressing rollers (roller surface temperature: 80 ℃) and silicone rubber-clad rollers. The double-sided copper-clad laminate 1 has no wrinkles and has good adhesion to the entire surface.

Example 2

A single-sided metal-clad laminate 2a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 2 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 2a' with the adhesive layer to obtain an adhesive sheet 2. The adhesive sheet 2 had a tensile elastic modulus of 1.03GPa, a tensile elongation of 165%, a tensile strength of 20MPa, a storage elastic modulus at 80℃of 14.1MPa, a CTE of 103ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0025, respectively, and a thickness unevenness of 0.65. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 2 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 2a' with the adhesive layer was used. The double-sided copper-clad laminate 2 has no wrinkles and has good adhesion to the entire surface.

Example 3

A single-sided metal-clad laminate 3a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 3 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 3a' with the adhesive layer to obtain an adhesive sheet 3. The adhesive sheet 3 had a tensile elastic modulus of 1.09GPa, a tensile elongation of 176%, a tensile strength of 19MPa, a storage elastic modulus at 80℃of 17.4MPa, a CTE of 98ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0025, respectively, and a thickness unevenness of 0.61. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 3 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 3a' with the adhesive layer was used. The double-sided copper-clad laminate 3 has no wrinkles and has good adhesion to the entire surface.

Example 4

A single-sided metal-clad laminate 4a' with an adhesive layer was obtained in the same manner as in example 2 except that the thickness after drying was 75 μm. The adhesive layer was peeled off from the single-sided metal-clad laminate 4a' with the adhesive layer, to obtain an adhesive sheet 4. The adhesive sheet 4 had a tensile elastic modulus of 1.04GPa, a tensile elongation of 166%, a tensile strength of 21MPa, a storage elastic modulus at 80℃of 14.3MPa, a CTE of 105ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0025, respectively, and a thickness unevenness of 1.22. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 4 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 4a' with the adhesive layer was used. The double-sided copper-clad laminate 4 has no wrinkles and has good adhesion to the entire surface.

Comparative example 1

A single-sided metal-clad laminate 5a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 4 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 5a' with the adhesive layer, and an adhesive sheet 5 was obtained. The adhesive sheet 5 had a tensile modulus of elasticity of 0.87GPa, a tensile elongation of 207%, a tensile strength of 31MPa, a storage modulus of elasticity at 80℃of 6.1MPa, a CTE of 122ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0022, respectively, and a thickness unevenness of 1.05. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 5 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 5a' with the adhesive layer was used. Wrinkles are generated in the double-sided copper-clad laminate 5, and poor adhesion due to the wrinkles is generated.

Comparative example 2

A single-sided metal-clad laminate 6a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 5 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 6a' with the adhesive layer to obtain an adhesive sheet 6. The adhesive sheet 6 had a tensile elastic modulus of 0.93GPa, a tensile elongation of 199%, a tensile strength of 27MPa, a storage elastic modulus at 80℃of 8.4MPa, a CTE of 118ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0022, respectively, and a thickness unevenness of 0.99. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 6 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 6a' with the adhesive layer was used. Wrinkles are generated in the double-sided copper-clad laminate 6, and poor adhesion due to the wrinkles is generated.

Comparative example 3

A single-sided metal-clad laminate 7a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 6 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 7a' with the adhesive layer, and an adhesive sheet 7 was obtained. The adhesive sheet 7 had a tensile modulus of elasticity of 0.97GPa, a tensile elongation of 192%, a tensile strength of 26MPa, a storage modulus of elasticity at 80℃of 9.7MPa, a CTE of 112ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0023, respectively, and a thickness unevenness of 0.85. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 7 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 7a' with the adhesive layer was used. The double-sided copper-clad laminate 7 is slightly wrinkled, and poor adhesion due to the wrinkles occurs.

Comparative example 4

A single-sided metal-clad laminate 8a' with an adhesive layer was obtained in the same manner as in example 4 except that the adhesive composition 4 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 8a' with the adhesive layer, to obtain an adhesive sheet 8. The adhesive sheet 8 had a tensile elastic modulus of 0.91GPa, a tensile elongation of 205%, a tensile strength of 30MPa, a storage elastic modulus at 80℃of 5.9MPa, a CTE of 120ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0022, respectively, and a thickness unevenness of 1.50. Mu.m. In addition, in the evaluation of the filler falling-off property, no void was found in the adhesive layer cross section, and no falling-off of OP945 was confirmed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

Next, a double-sided copper-clad laminate 8 was obtained in the same manner as in example 1, except that the single-sided metal-clad laminate 8a' with the adhesive layer was used. Wrinkles are generated in the double-sided copper-clad laminate 8, and poor adhesion due to the wrinkles is generated.

Example 5

The adhesive composition 2 was applied to one surface of a long release PET film 1 (trade name: HY-S05, thickness: 25 μm) so that the thickness after drying became 60 μm, and the adhesive layer was peeled off from the release PET film 1 by heating and drying stepwise from 80 to 160 ℃. The adhesive sheet 9 had a tensile elastic modulus of 1.05GPa, a storage elastic modulus at 80℃of 13.9MPa, a tensile elongation of 163%, a tensile strength of 20MPa, a CTE of 100ppm/K, dk and Df at the time of humidity control of 2.70 and 0.0025, respectively, and a thickness unevenness of 0.67. Mu.m. In addition, in the evaluation of the filler falling-off property, as shown in fig. 5, no voids in the adhesive layer cross section were observed, and no falling-off of OP945 was observed. Further, even when the surface view of any ten portions was observed, no filler component having a particle diameter exceeding 10 μm and no filler-removed portion having a length exceeding 10 μm were observed in the surface view of 100 μm×100 μm.

The two long single-sided metal-clad laminate 1 was placed with the surfaces of the insulating resin layers in contact with both surfaces of the adhesive sheet 9, and continuously overlapped and continuously thermally pressed by using a heating and pressing device having at least one pair of metal heating and pressing rollers (roller surface temperature: 80 ℃) and silicone rubber-clad rollers while conveying them via guide rollers, thereby obtaining a double-sided copper-clad laminate 9. The double-sided copper-clad laminate 9 has no wrinkles and has good adhesion to the entire surface.

Comparative example 5

A single-sided metal-clad laminate 10a' with an adhesive layer was obtained in the same manner as in example 1 except that the adhesive composition 7 was used. The adhesive layer was peeled off from the single-sided metal-clad laminate 10a' with the adhesive layer, and the adhesive sheet 10 was obtained. The adhesive sheet 10 had a tensile modulus of elasticity of 1.05GPa, a tensile elongation of 162%, a tensile strength of 19MPa, a storage modulus of elasticity at 80℃of 14.2MPa, a CTE of 102ppm/K, dk and Df of 2.70 and 0.0025, respectively, and a thickness unevenness of 0.68. Mu.m. In addition, in the evaluation of the filler falling-off property, as shown in fig. 6, the filler component having a particle diameter of 10 μm or more and voids in the cross section of the adhesive layer (filler falling-off portions having a length of more than 10 μm) were observed, and the state of coarse particles falling off in OP935 was observed.

As described above, the adhesive sheets 1 to 4 and 9 in the examples are blended at a high concentration of OP945, and the tensile modulus and the storage modulus at 80 ℃ are increased, so that deformation due to shear stress when the single-sided metal-clad laminate is laminated is less likely to occur, and the effect of suppressing wrinkles due to the deformation is obtained. Further, it is considered that the OP945 is blended at a high concentration, so that friction between inorganic particles in the adhesive composition is easily generated, and fluidity at high temperature is suppressed, and thus thickness unevenness is reduced. In comparative example 5, when the adhesive sheet is produced by blending a resin composition in which OP935 having a maximum particle diameter of 10 μm or more is blended at a high concentration by a conventional blending method in which a filler is directly blended into a diluted resin varnish, the particle diameter in the adhesive sheet is large, and the filler is easily detached due to shear stress caused by cutting. Therefore, in the form of the comparative example, there is a concern that foreign matter is generated in the process due to the filler falling off at the time of cutting processing or that the through hole plating is poor due to the filler falling off at the time of drilling and perforating processing.

< Preparation of laminate film 1-laminate film 9 >

Slit processing is performed on the double-sided copper-clad laminated board 1-double-sided copper-clad laminated board 9, the laminated board is cut into a predetermined size, then the cut board is placed in a constant temperature tank, heating treatment is performed at 180 ℃ for 24 hours, and then a copper foil layer is etched and removed by using an aqueous solution of ferric chloride, so that laminated films 1-9 with the thickness of 100-125 μm are prepared.

The dielectric properties of the adhesive sheet 1 to the adhesive sheet 9, and the dielectric properties and the flame retardancy evaluation results of the laminated films 1 to 9 are shown in table 1.

TABLE 1

The Df of the adhesive sheet during humidity control tends to increase as OP945 increases, but the Df of the laminated films 1 to 9 show the same value. In addition, df at the time of water absorption of the adhesive sheet showed a tendency to show a more significant increase with an increase in OP945 than at the time of conditioning. On the other hand, in examples 1 to 5, df at the time of water absorption of the laminated film showed a lower value than the calculated value of Df calculated from the thickness ratio of the polyimide film 1 and the Df at the time of water absorption of the adhesive sheet. Even if Df is deteriorated when water is absorbed in the adhesive sheet, the polyimide film 1 is laminated on both sides, and as a result, water absorption in the adhesive sheet is suppressed.

The estimated value of Df at the time of water absorption of the laminated film is calculated based on the following equation (1).

[ Number 1]

Df _T estimation of Df at the time of absorption of laminated film

Thickness of laminated film T _T

Df _P Df at the time of water absorption of polyimide film 1

T _P total thickness of polyimide film 1 (two layers)

Df _A Df at the time of water absorption of the adhesive sheet

T _A thickness of adhesive sheet

Regarding the flame retardancy, the probability that the burning time (t 1) of 10 samples was less than 10 seconds was evaluated as "o" in the case where the number of samples was more than 80% in each of the laminated films 1 to 4 and 9 shown in examples, and as "x" in the case where the number of samples was 80% or less in each of the laminated films 5 to 8 shown in comparative examples.

As described in detail above, the laminate and the metal-clad laminate according to the embodiments of the present invention have excellent dielectric characteristics, flame retardancy, and workability, and are considered to be a design capable of suppressing thickness unevenness and wrinkles at the time of lamination.

Although the embodiments of the present invention have been described in detail for the purpose of illustration, the present invention is not limited to the embodiments, and various modifications are possible.

Claims

1. A laminate, comprising:

A first insulating resin layer;

a second insulating resin layer, and

An adhesive layer laminated between the first insulating resin layer and the second insulating resin layer so as to be in contact with the layers, the laminate being characterized in that,

The total thickness T1 of the first insulating resin layer, the adhesive layer and the second insulating resin layer is in the range of 70 [ mu ] m to 500 [ mu ] m, the thickness T2 of the adhesive layer is in the range of more than 50 [ mu ] m and not more than 450 [ mu ] m, the ratio (T2/T1) of T2 to T1 is in the range of more than 0.5 and not more than 0.96,

The adhesive layer contains a resin component and a filler component,

The resin component contains a polyimide having a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component, and contains 40 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups,

The filler component contains a metal salt of an organic phosphinic acid, and the weight ratio of the filler component to the total amount of the resin components is in the range of more than 40 parts by weight and 90 parts by weight or less.

2. The laminate according to claim 1, wherein a total area ratio of a filler component having a particle diameter of more than 10 μm and a filler-removed portion having a length of more than 10 μm in a surface field of 100 μm x 100 μm when the adhesive layer is observed in a cross section in a thickness direction of the adhesive layer by a scanning electron microscope is 1% or less on an average of the surface fields of any ten sites.

3. The laminate according to claim 1, wherein the polyimide is a polyimide having a ketone group in a molecule, and the resin component contains a crosslinking agent having a functional group that reacts with the ketone group in a nucleophilic manner.

4. The laminate according to claim 1, wherein the polyimide forms a crosslinked structure by a reaction of a person having a ketone group in the molecule with a crosslinking agent having a functional group that undergoes a nucleophilic reaction with respect to the ketone group.

5. The laminate according to claim 1, wherein the adhesive layer has a tensile elastic coefficient in a range of 1.0GPa or more and 1.2GPa or less.

6. The laminate according to claim 1, wherein the adhesive layer has a storage elastic modulus at 80 ℃ in a range of 10MPa or more and 20MPa or less.

7. The laminate according to claim 1, wherein the first insulating resin layer and the second insulating resin layer are multilayered polyimide layers having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer.

8. The laminate of claim 7, wherein the outermost layer of the multi-layer polyimide layer is a thermoplastic polyimide layer.

9. The laminate according to claim 1, wherein the length in the width direction (transverse direction) is in the range of 0.2m or more and 2.0m or less, and is long.

10. A metal-clad laminate comprising the laminate according to any one of claims 1 to 7, and a metal layer laminated on one or both sides of the laminate.

11. A circuit board comprising the laminate according to any one of claims 1 to 7, and a wiring layer laminated on one or both sides of the laminate.

12. An electronic component comprising the circuit substrate according to claim 11.

13. An electronic device comprising the circuit substrate according to claim 11.

14. An adhesive resin composition comprising a resin component, a filler component and an organic solvent,

The filler component comprises a metal salt of an organic phosphinic acid,

The weight ratio of the filler component to the total amount of the resin components of 100 parts by weight is in the range of more than 40 parts by weight and 90 parts by weight or less,

The tensile elastic modulus when forming a film with a thickness in the range of more than 50 μm and 450 μm or less is in the range of 1.0GPa to 1.2GPa, and the storage elastic modulus at 80 ℃ is in the range of 10MPa to 20 MPa.

15. A method for producing an adhesive resin composition, is a method for producing the adhesive resin composition according to claim 14, the method for producing the adhesive resin composition is characterized by comprising the following steps (i) and (ii);

(Ii) A step of mixing the remaining part of the resin component with an organic solvent into the filler dispersion and stirring the mixture to obtain the adhesive resin composition,

In the step (i), the weight ratio of the resin component in the filler dispersion is set to be in the range of 3 to 15 parts by weight with respect to 100 parts by weight of the final total amount of the resin components, and the solid content concentration in the filler dispersion is adjusted to be in the range of 40 to 60% by weight, and in the step (ii), the weight ratio of the filler component in the adhesive resin composition is set to be in the range of more than 40 to 90 parts by weight with respect to 100 parts by weight of the final total amount of the resin components.

16. An adhesive film comprising a resin component and a filler component,

The filler component comprises a metal salt of an organic phosphinic acid,

The thickness is in the range of more than 50 μm and 450 μm or less,

The tensile elastic modulus is in the range of 1.0GPa to 1.2GPa, and the storage elastic modulus at 80 ℃ is in the range of 10MPa to 20MPa.