JP2008272958A - Method for producing single-sided metal clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a single-sided metal clad laminate the metal foil of which is prevented from being fusion-bonded to a metal roll or a protective material when overlaying the metal foil on an adhesive sheet and keeps the warpage suppressed. <P>SOLUTION: In the method for producing the single-sided metal clad laminate by heat-pressing the metal foil on one side of an adhesive sheet in which thermoplastic resin layers are set on both sides of a heat resistant film, the protective material is arranged between the press surface of a thermocompression bonding apparatus and the adhesive sheet when the metal foil is thermally compressed, and the adhesive strength between the thermoplastic resin layer overlaid with no metal foil and the protective material is 0.05-5 N/cm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a single-sided metal-clad laminate suitably used for a flexible printed wiring board and the like. More specifically, the present invention relates to a method for producing a single-sided metal-clad laminate comprising at least a conductor and a plurality of polyimide layers.

  Conventionally, as a flexible laminated board suitable as a printed circuit board for electronic and electrical equipment, a structure in which a metal foil is laminated on both front and back surfaces of a polyimide film by thermal lamination or the like is known, and a flexible laminate having such a structure is known. As a method for producing a laminate, a method of thermally laminating a polyimide film and a metal foil in a state where a protective film is interposed between a pair of metal rolls at the time of thermal lamination at a high temperature has been proposed (for example, Patent Document 1). reference).

  By the way, the polyimide film used as described above is an adhesive sheet having a structure in which a non-thermoplastic polyimide layer is used as a core layer (heat resistant film) and thermoplastic polyimide layers are arranged on both front and back surfaces of the core layer. There are many. Moreover, the flexible laminated board manufactured using such an adhesive sheet laminated | stacked metal foil on the front and back of the film by making metal foil contact | abut to the thermoplastic polyimide layer of the said polyimide film, and heat-laminating it. A structure is common.

  However, for example, in the case of producing a multi-layer laminate, if a multi-layer structure is formed by laminating a number of the double-sided metal-clad flexible laminate, the metal foils are in contact with each other and laminated, In order to avoid this, it is required to use a flexible laminate having a structure in which metal foil is laminated only on one side. Alternatively, in some cases, it is not necessary to form wiring layers on both the front and back sides of the printed circuit board for electronic and electrical equipment. Even in such a case, it is required to use a flexible laminate having a structure in which metal foil is laminated only on one side.

  By the way, in the flexible laminate in which the metal foil is laminated only on one side of the adhesive sheet in which the thermoplastic polyimide layers are arranged on both sides of the core layer, the surface on which the metal foil is not laminated at the time of the above-mentioned thermal lamination. There exists a problem that the thermoplastic polyimide layer which exists exists in the above-mentioned metal roll and protective film, and the manufacture itself is difficult.

  On the other hand, for the purpose of preventing the thermoplastic polyimide layer existing on the surface where the metal foil is not laminated from being fused to a metal roll or the like, the thermoplastic polyimide layer is provided only on the surface where the metal foil is laminated. If provided, the balance of the linear expansion coefficient of the adhesive sheet is out of order, which may cause a problem that warpage occurs in the state of the adhesive sheet or the obtained metal-clad laminate.

  As an attempt to solve the above problem, a method for forming a backing layer using a non-thermoplastic polyimide layer instead of the thermoplastic polyimide layer present on the surface of the adhesive sheet on which the metal foil is not laminated has been proposed. (For example, refer to Patent Document 2).

Certainly, according to the method of Patent Document 2, the problem of fusing to a metal roll or a protective film when producing a metal-clad laminate is solved, and warpage of the resulting laminate can be suppressed. However, in order to provide the backing layer, it is necessary to synthesize a third component different from the core layer and the thermoplastic polyimide layer, which causes a problem that the manufacturing process becomes complicated.
JP 2001-129918 A JP 2005-186274 A (claim, paragraph number 0009)

  The present invention solves the above-described problems, and the surface of the thermoplastic resin layer on the side where the metal foil is not laminated is a metal roll or the like, although the thermoplastic resin layers are provided on both surfaces of the heat-resistant film as the core layer. An object of the present invention is to provide a method for producing a single-sided metal-clad laminate that can produce a single-sided metal-clad laminate that is capable of producing a single-sided metal-clad laminate without being fused to a protective film, and that can suppress warpage. .

  As a result of intensive studies to solve the above problems, the present inventors have found that the desired single-sided metal-clad laminate can be obtained by the following method, and have completed the present invention.

  That is, the present invention is a method for producing a single-sided metal-clad laminate by thermocompression bonding a metal foil on one side of an adhesive sheet provided with a thermoplastic resin layer on both sides of a heat-resistant film, the thermocompression bonding, A protective material is disposed between the pressure surface of the thermocompression bonding apparatus and the adhesive sheet, and the adhesion strength between the thermoplastic resin layer on the side where the metal foil is not laminated and the protective material is in the range of 0.05 to 5 N / cm. The present invention relates to a method for producing a single-sided metal-clad laminate.

  In a preferred embodiment, the adhesive strength between the thermoplastic resin layer on the side on which the metal foil is not laminated and the protective material is controlled by containing a filler in the thermoplastic resin layer, The present invention relates to a method for producing a metal-clad laminate.

  In a preferred embodiment, the heat-resistant film is a non-thermoplastic polyimide film, and relates to a method for producing any one of the single-sided metal-clad laminates.

  In a preferred embodiment, the thermoplastic resin layer provided on both surfaces of the heat-resistant film includes a thermoplastic polyimide resin, and relates to a method for producing any one of the single-sided metal-clad laminates.

  A preferred embodiment relates to the method for producing a single-sided metal-clad laminate, wherein the thermoplastic resin layers provided on both surfaces of the heat-resistant film contain the same kind of thermoplastic polyimide resin.

  In a preferred embodiment, the thermocompression bonding apparatus is a heat roll laminating apparatus having one or more pairs of metal rolls.

  A preferred embodiment relates to a method for producing any one of the single-sided metal-clad laminates, wherein the protective material is a non-thermoplastic polyimide film.

  According to the present invention, when a single-sided metal-clad laminate is manufactured by thermocompression bonding of a heat-resistant adhesive sheet and a metal foil, the tackiness of the surface of the thermoplastic resin layer on the side not in contact with the metal foil is controlled. Therefore, sticking to a metal roll, a protective material, a press plate or the like can be avoided, and productivity can be improved. The production method of the present invention exhibits a remarkable effect particularly when a single-sided metal-clad laminate is continuously produced by a thermal lamination method.

  Embodiments of the present invention will be described in detail below.

  The method for producing a single-sided metal-clad laminate according to the present invention is a method for producing a single-sided metal-clad laminate by thermocompression bonding a metal foil to one side of a laminate in which a thermoplastic resin layer is provided on both sides of a heat-resistant film. It is characterized by controlling the surface tackiness of the thermoplastic resin layer on the side not in contact with the metal foil during thermocompression bonding, that is, the adhesion strength between the thermoplastic resin layer and the protective material when the protective material is arranged. Yes.

  Conventionally, as an adhesive sheet used for producing a single-sided metal-clad laminate, a thermoplastic polyimide layer serving as an adhesive layer is provided on one side of a core layer made of a non-thermoplastic polyimide film, and a backing layer is provided on the other side. Has been manufactured by. Since the metal foil is not laminated on the backing layer, it is necessary to avoid sticking of the backing layer to, for example, a metal roll, a protective material, a press plate, or the like when the adhesive sheet and the metal foil are thermocompression bonded. Therefore, non-thermoplastic polyimide is used as the backing layer.

  However, in order to control the linear expansion coefficient of the obtained single-sided metal-clad laminate, the composition of the polyimide resin used as the backing layer is often different from that of the core layer and thermoplastic polyimide layer, and the manufacturing process is complicated. Problems such as becoming. In general, the difference in coefficient of linear expansion between the non-thermoplastic polyimide resin contained in the backing layer and the thermoplastic polyimide resin contained in the adhesive layer is large, so that it is not possible to balance the backing layer and the adhesive layer. It's not easy. If the thickness of the backing layer is significantly higher than the thickness of the adhesive layer in an attempt to balance the above, the solvent contained in the adhesive sheet cannot be removed during the drying process, or the adhesive sheet or single-sided metal-clad laminate is caused by foaming. The appearance of a board or the like may be deteriorated. On the other hand, if an adhesive sheet for a double-sided metal-clad laminate having a thermoplastic resin layer on both sides of the core layer is used as it is for a single-sided metal-clad laminate, the adhesive sheet will be stuck by fusion to a metal roll or a protective material. It becomes a problem.

  In the present invention, the surface of the thermoplastic resin layer on the side where the metal foil is not laminated when the metal foil and the thermocompression bonding are provided, even though the thermoplastic resin layer is provided on both surfaces of the heat-resistant film serving as the core layer. By controlling the tackiness of the resin, for example, the composition of the thermoplastic resin layer can be made the same on the front and back, and the productivity can be remarkably improved. Moreover, it is also preferable to provide a thermoplastic resin layer on both surfaces of the core layer from the viewpoint of reducing the difference in linear expansion coefficient between the outermost layers in the adhesive sheet.

  In the present invention, if the linear expansion coefficient of the polyimide resin as the backing layer is α1 (ppm / ° C.) and the linear expansion coefficient of the polyimide resin as the adhesive layer is α2 (ppm / ° C.), then | α1−α2 | ≦ 15 It is preferable to set so that If the difference in the linear expansion coefficient is within the above range, it is possible to cope with the control of the thickness balance between the adhesive layer and the backing layer when controlling the linear expansion coefficient of the entire adhesive sheet described later.

  As a method for controlling the tackiness of the surface, for example, a method of adding a filler to the thermoplastic resin layer, a method of adjusting the glass transition temperature (hereinafter also referred to as Tg) of the surface resin, or a thermoplastic as a thermoplastic resin. In the case of using a polyimide resin, a method for adjusting firing conditions when forming on a heat-resistant film, a method for adjusting surface strength, and the like can be mentioned. These methods can be used alone or in combination to appropriately reduce the tackiness to a specific range.

  The tackiness of the thermoplastic resin layer on the side where the metal foil is not laminated in the adhesive sheet according to the present invention can be determined by the adhesion strength between the protective material after thermocompression bonding and the thermoplastic resin layer. The adhesion strength is preferably 0.05 to 5 N / cm. For the adhesion strength, a sample was prepared with reference to “8.1 Copper foil peeling strength” of JIS C6471, and a 1 cm wide protective material was peeled off at a peeling angle of 90 degrees and 50 mm / min. It can be determined by measuring the load.

  The protective material in the present invention is not particularly limited as long as it satisfies the purpose of preventing wrinkles and the like of the single-sided metal-clad laminate produced by thermocompression bonding. However, it must be able to withstand the processing temperature. For example, when processing at 250 ° C., a non-thermoplastic polyimide film or the like is effective because it must have heat resistance higher than that. Can be used. The thickness of the protective material is not particularly limited, but is preferably 50 μm or more in order to suppress wrinkling and the like of the single-sided metal-clad laminate after thermocompression bonding. If the thickness of the protective material is 75 μm or more, wrinkle generation can be almost completely suppressed, which is more preferable. More preferably, it is 125 μm or more.

  The present inventors have found that the surface tackiness during heating of the thermoplastic resin layer can be suitably controlled by including a filler in the thermoplastic resin layer on the side where the metal foil is not laminated in the adhesive sheet. ing. Conventionally, when a filler is added to a polyimide film, many are aimed at improving slipperiness, and as in the present invention, the addition of a filler controls the surface tackiness during heating of a thermoplastic resin layer. The finding that it is possible to do so was first discovered by the present inventors.

  Hereinafter, as a method for controlling the tackiness of the surface of the backing layer to a specific range, for a mode in which a filler is used, a heat-resistant film, a thermoplastic resin layer, a filler contained in a thermoplastic resin layer as a backing layer, and an adhesive sheet Will be described in the order of the manufacturing method, the metal foil, and the manufacturing method of the single-sided metal-clad laminate.

<Heat resistant film>
In the present invention, “heat resistance” means that it can withstand use at a heating temperature during thermal lamination. Accordingly, the heat resistant film is not particularly limited as long as it satisfies the above properties, and various known films such as polyimide film and polyethylene naphthalate can be used. Of these, a heat-resistant polyimide film is preferable from the viewpoint of excellent physical properties such as electrical characteristics as well as heat resistance.

  The “heat-resistant polyimide film” may be formed by containing 90% by weight or more of non-thermoplastic polyimide, and the molecular structure and thickness of non-thermoplastic polyimide are not particularly limited. The non-thermoplastic polyimide used for forming the heat-resistant polyimide film is generally produced using polyamic acid as a precursor. However, the non-thermoplastic polyimide may be completely imidized or imide An unconverted precursor, that is, a polyamic acid, may be included in part. Here, the non-thermoplastic polyimide generally refers to a polyimide that does not soften or show adhesiveness even when heated. In the present invention, it refers to a polyimide that is heated in a film state at 450 ° C. for 2 minutes, does not wrinkle or stretch, and maintains its shape, or has substantially no glass transition temperature. The glass transition temperature can be obtained from the value of the inflection point of the storage elastic modulus measured by a dynamic viscoelasticity measuring device (DMA). Further, “substantially has no glass transition temperature” means that thermal decomposition starts before the glass transition state is reached.

  In general, a polyimide film can be manufactured using polyamic acid as a precursor. Any known method can be used as a method for producing the polyamic acid, and usually, the aromatic tetracarboxylic dianhydride and the aromatic diamine are controlled by dissolving substantially equimolar amounts in an organic solvent. It can be produced by stirring under temperature conditions until the polymerization of the acid dianhydride and the diamine is completed. These polyamic acid solutions are usually obtained at a concentration of 5 to 35% by weight, preferably 10 to 30% by weight. When the concentration is in this range, a suitable molecular weight and solution viscosity can be obtained.

As the polymerization method, any known method and a combination thereof can be used. The characteristic of the polymerization method in the polymerization of polyamic acid is the order of addition of the monomers, and various physical properties of the polyimide obtained can be controlled by controlling the order of addition of the monomers. Therefore, in the present invention, any method of adding monomers may be used for the polymerization of polyamic acid. The following method is mentioned as a typical polymerization method. That is,
1) A method in which an aromatic diamine is dissolved in an organic polar solvent, and this is reacted with a substantially equimolar aromatic tetracarboxylic dianhydride for polymerization.
2) An aromatic tetracarboxylic dianhydride is reacted with a small molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Then, the method of superposing | polymerizing using an aromatic diamine compound so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in all the processes.
3) An aromatic tetracarboxylic dianhydride is reacted with an excess molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Then, the method of superposing | polymerizing using an aromatic tetracarboxylic dianhydride so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in all the processes.
4) A method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized using an aromatic diamine compound so as to be substantially equimolar.
5) A method in which a substantially equimolar mixture of aromatic tetracarboxylic dianhydride and aromatic diamine is reacted in an organic polar solvent for polymerization.
And so on. These methods may be used singly or in combination.

  In the present invention, the polyamic acid obtained by using any of the above polymerization methods may be used, and the polymerization method is not particularly limited.

  In this invention, it is also preferable to use the polymerization method which obtains the said prepolymer using the diamine component which has a rigid structure mentioned later. By using this method, a polyimide film having a high elastic modulus and a small hygroscopic expansion coefficient tends to be easily obtained. In the above method, the molar ratio of the diamine having a rigid structure and the acid dianhydride used when preparing the prepolymer is 100: 70 to 100: 99 or 70: 100 to 99: 100, and further 100: 75 to 100: 90 or 75: 100-90: 100 is preferable. If this ratio is below the above range, it is difficult to obtain the effect of improving the elastic modulus and the hygroscopic expansion coefficient. Conversely, if the ratio is above the above range, the linear expansion coefficient may become too small or the tensile elongation may be reduced. is there.

  Suitable tetracarboxylic dianhydrides for the production of non-thermoplastic polyimide resins for forming the heat-resistant polyimide film are pyromellitic dianhydride and 2,3,6,7-naphthalene tetracarboxylic dianhydride. 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride Anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane Water, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride Bis (3,4-dicarboxyphenyl) sulfone dianhydride, p-phenylene bis (trimellitic acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (tri Merit acid monoester anhydride) and the like, and these may be used alone or in a mixture of any ratio.

  Among these acid dianhydrides, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,3 ′ It is preferable to use at least one selected from 4,4'-biphenyltetracarboxylic dianhydride.

  Among these acid dianhydrides, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-biphenyl The preferred amount of use in the case of using at least one selected from tetracarboxylic dianhydrides is 60 mol% or less, preferably 55 mol% or less, more preferably 50 mol% or less, based on the total amount of total acid dianhydrides. 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride When using at least one kind, if the amount used exceeds this range, the glass transition temperature of the heat-resistant polyimide film may become too low, or the storage elastic modulus during heat may become too low, making film formation itself difficult. .

  Moreover, when using pyromellitic dianhydride, a preferable usage-amount is 40-100 mol% with respect to the total amount of total acid dianhydrides, More preferably, it is 45-100 mol%, Most preferably, it is 50-100 mol%. By using pyromellitic dianhydride in this range, the glass transition temperature and the storage modulus during heat tend to be easily maintained in a range suitable for use or film formation.

  Examples of suitable diamines that can be used in the polyamic acid composition that is a precursor of a non-thermoplastic polyimide resin for forming the heat-resistant polyimide film include 4,4′-diaminodiphenylpropane and 4,4′-diaminodiphenylmethane. , Benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 4,4'-diaminodiphenyl Sulfide, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 4,4′-oxydianiline, 3,3′-oxydianiline, 3,4′-oxydianiline, 1,5 -Diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-di Minodiphenylsilane, 4,4′-diaminodiphenylethylphosphine oxide, 4,4′-diaminodiphenyl N-methylamine, 4,4′-diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine) ), 1,3-diaminobenzene, 1,2-diaminobenzene, bis {4- (4-aminophenoxy) phenyl} sulfone, bis {4- (4-aminophenoxy) phenyl} propane, bis {4- (3 -Aminophenoxy) phenyl} sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1 , 3-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) Benzene, 1,3-bis (3-aminophenoxy) benzene, 3,3'-benzophenone, 4,4'-diamino benzophenone and their analogs thereof.

  As the diamine component, a diamine having a rigid structure and an amine having a flexible structure can be used in combination, and the preferred use ratio in that case is 80/20 to 20/80, more preferably 70/30 to 30/70, in molar ratio. Particularly, it is 60/40 to 30/70. If the use ratio of the rigid diamine exceeds the above range, the tensile elongation of the resulting film tends to be small, and if it falls below this range, the glass transition temperature becomes too low or the storage modulus during heat decreases. In some cases, the film formation is difficult, and it may be harmful.

  In the present invention, the diamine having a rigid structure means one represented by the following general formula (1).

式中のＲ_２は

R ₂ in the formula is

で表される２価の芳香族基からなる群から選択される基であり、式中のＲ_３は同一または異なってもよく、Ｈ−，ＣＨ_３−、−ＯＨ、−ＣＦ_３、−ＳＯ_４、−ＣＯＯＨ、−ＣＯ-ＮＨ_２、Ｃｌ−、Ｂｒ−、Ｆ−、及びＣＨ_３Ｏ−からなる群より選択される何れかの１つの基である。

And R _{3 in} the formula may be the same or different, and H—, CH ₃ —, —OH, —CF ₃ , —SO 2 may be selected from the group consisting of divalent aromatic groups represented by ₄ , any one group selected from the group consisting of —COOH, —CO—NH ₂ , Cl—, Br—, F—, and CH ₃ O—.

  The diamine having a flexible structure is a diamine having a flexible structure such as an ether group, a sulfone group, a ketone group, or a sulfide group, and is preferably represented by the following general formula (2).

式中のＲ_４は、

R ₄ in the formula is

で表される２価の有機基からなる群から選択される基であり、式中のＲ_５は同一または異なってもよく、Ｈ−，ＣＨ_３−、−ＯＨ、−ＣＦ_３、−ＳＯ_４、−ＣＯＯＨ、−ＣＯ-ＮＨ_２、Ｃｌ−、Ｂｒ−、Ｆ−、及びＣＨ_３Ｏ−からなる群より選択される１つの基である。

R _{5 in} the formula may be the same or different, and H—, CH ₃ —, —OH, —CF ₃ , —SO ₄ may be selected from the group consisting of divalent organic groups represented by , —COOH, —CO—NH ₂ , Cl—, Br—, F—, and CH ₃ O—.

  The heat-resistant polyimide film that can be used in the present invention is obtained by appropriately determining the type and blending ratio of aromatic dianhydride and aromatic diamine so as to have desired characteristics within the above range. be able to.

  As the preferred solvent for synthesizing the polyamic acid, any solvent can be used as long as it dissolves the polyamic acid, but amide solvents, that is, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are suitable, and N, N-dimethylformamide and N, N-dimethylacetamide can be particularly preferably used.

  In addition, a filler can be added to the heat resistant film for the purpose of improving various properties of the film such as slidability, thermal conductivity, conductivity, corona resistance, and loop stiffness. Any filler may be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica and the like.

  Since the number average particle size of the filler is determined by the film characteristics to be modified and the type of filler to be added, it is not particularly limited, but generally the number average particle size is 0.05 to 100 μm, preferably It is 0.1 to 75 μm, more preferably 0.1 to 50 μm, and particularly preferably 0.1 to 25 μm. If the particle diameter is below this range, the effect of improving the slidability and the like is less likely to appear. Conversely, if the particle diameter is above this range, the surface property may be greatly impaired or the mechanical properties may be greatly deteriorated. Further, the number of added parts of the filler is not particularly limited because it is determined by the film properties to be modified, the filler particle diameter, and the like. Generally, the addition amount of the filler is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight with respect to 100 parts by weight of the polyimide resin. If the amount of filler added is less than this range, the effect of modifying the filler such as slidability hardly appears, and if it exceeds this range, the mechanical properties of the film may be greatly impaired.

As a method for adding the filler, for example,
1. 1. A method of adding to a polymerization reaction solution before or during polymerization 2. A method of kneading fillers using three rolls after the completion of polymerization. Any method such as preparing a dispersion containing filler and mixing it with a polyamic acid organic solvent solution may be used, but a method of mixing a dispersion containing filler with a polyamic acid solution, particularly immediately before film formation. This method is preferable because the contamination by the filler in the production line is minimized. When preparing a dispersion containing a filler, it is preferable to use the same solvent as the polymerization solvent for the polyamic acid. Further, in order to disperse the filler satisfactorily and stabilize the dispersion state, a dispersant, a thickener and the like can be used within a range not affecting the film physical properties.

  The solution having the non-thermoplastic polyimide resin precursor thus obtained is also referred to as a solution containing a heat-resistant polyimide precursor.

<Thermoplastic resin layer>
In the present invention, examples of the thermoplastic resin layer include polycarbonate resins, acrylonitrile / styrene copolymer resins, thermoplastic polyimide resins, etc., but from the viewpoint of heat resistance, thermoplastic polyimide resins are particularly preferably used. Can be. If the thermoplastic polyimide resin exhibits desired properties such as a significant adhesive force with a metal foil and a suitable linear expansion coefficient, the content, molecular structure, and thickness of the thermoplastic polyimide resin contained in the layer are as follows. It is not particularly limited. However, it is preferable that substantially 50% by weight or more of the thermoplastic polyimide resin is contained in the thermoplastic resin layer in order to exhibit desired properties such as significant adhesive strength and a suitable linear expansion coefficient. Furthermore, the thermoplastic polyimide resin contained in the thermoplastic resin layer facing through the heat-resistant film is the same type from the viewpoint of balancing the linear expansion coefficient in the entire adhesive sheet and simplifying the manufacturing process. Is preferred.

  As the thermoplastic polyimide resin contained in the thermoplastic resin layer, for example, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide and the like can be suitably used.

  The thermoplastic polyimide contained in the thermoplastic resin layer can be obtained by a conversion reaction from the precursor polyamic acid. As the method for producing the polyamic acid, any known method can be used as in the case of the precursor of the non-thermoplastic polyimide resin that can be used for the heat-resistant film.

  Moreover, the thermoplastic polyimide resin used in the present invention is in the range of 150 to 300 ° C. in terms of expressing significant adhesive strength with the metal foil and not impairing the heat resistance of the obtained single-sided metal-clad laminate. It preferably has a glass transition temperature (Tg). In addition, Tg can be calculated | required from the value of the inflexion point of the storage elastic modulus measured with the dynamic viscoelasticity measuring apparatus (DMA).

  The polyamic acid that is a precursor of the thermoplastic polyimide that can be used in the present invention is not particularly limited, and any known polyamic acid can be used. Regarding the production of the polyamic acid solution, the raw materials exemplified above and the production conditions can be selected as appropriate and used in the same manner.

  The thermoplastic polyimide can be adjusted in various properties by combining various raw materials such as acid dianhydride component and diamine component to be used, but generally the glass transition temperature increases as the proportion of rigid structure diamine increases. In some cases, it becomes higher and / or the storage elastic modulus at the time of heating becomes larger and the adhesion and workability become lower. For example, the use ratio of the rigid structure diamine is preferably 40 mol% or less, more preferably 30 mol% or less, particularly preferably 20 mol% or less, based on the total amount of diamine.

  Specific examples of preferable thermoplastic polyimide resins include benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride, biphenylsulfone tetracarboxylic dianhydride, and other acid dianhydrides and aminophenoxy. Examples thereof include those obtained by polymerizing a diamine having a group.

  Furthermore, for the purpose of controlling the slipperiness of the adhesive sheet according to the present invention, an inorganic or organic filler, and other resins may be added as necessary.

<Filler contained in thermoplastic resin layer as backing layer>
In the present invention, the surface tackiness of the thermoplastic resin layer on which the metal foil is not laminated (hereinafter, the thermoplastic resin layer is also referred to as the backing layer) is controlled to be small, and the adhesion strength with the protective material is set within a specific range. Therefore, for example, means for adjusting the glass transition temperature of the surface resin, means for adjusting the firing conditions when forming on the heat resistant film when using a thermoplastic polyimide resin as the thermoplastic resin, Means for adjusting, means for containing a filler in the backing layer, and the like can be used.

  Hereinafter, a means for controlling the surface tackiness to be small by adding a filler to the backing layer will be described.

  Examples of the filler added to the backing layer include inorganic fillers such as silica, talc, mica, alumina, titanium oxide, zinc oxide, and calcium carbonate, or organic fillers such as fluorine resin and benzoguanamine resin. Can do.

  The number average particle diameter of the filler is not particularly limited as long as the surface tack can be controlled, but is preferably 0.1 to 10 μm from the following viewpoints. When the average particle size of the filler is less than 0.1 μm, it is necessary to add a large amount of filler to reduce the surface tackiness of the backing layer. In this case, the linear expansion coefficient between the outermost layers of the adhesive sheet is required. The difference tends to increase. Since the backing layer is not patterned, a filler with a large particle size can be added. However, if the average particle size exceeds 10 μm, voids tend to occur during lamination, and inconvenience tends to occur in the mounting process. There is. Further, it is preferable to use a filler having a sharp particle size distribution and low cohesion. When the filler aggregates in the backing layer, the surface tackiness may not change even if the filler is added. The addition amount of the filler is preferably 2 to 50 parts by weight with respect to 100 parts by weight of the thermoplastic resin contained in the backing layer.

  Further, when a thermoplastic polyimide resin is used for the backing layer, the linear expansion coefficient of the polyimide resin as the backing layer is α1 (ppm / ° C.), and the linear expansion coefficient of the polyimide resin as the adhesive layer on the opposite surface is α2 (ppm / ° C.). ), It is preferable to add the filler in the range of | α1−α2 | ≦ 15. If it is in the said range, when controlling the linear expansion coefficient of the whole adhesive sheet mentioned later, it becomes possible to respond by controlling the thickness balance between the adhesive layer and the backing layer.

<Method for producing adhesive sheet>
Although it does not specifically limit about the manufacturing method of the adhesive sheet concerning this invention, In the case of the adhesive sheet of the said three-layer structure, a thermoplastic resin layer is put into the heat resistant film used as a core layer for every one side, or both surfaces simultaneously Examples thereof include a forming method, a method in which a thermoplastic resin layer is formed into a sheet shape, and this is bonded to the surface of the heat-resistant film serving as the core layer. Or the method of producing the adhesive sheet which co-extrudes the heat resistant film used as a core layer and a thermoplastic resin layer, and forms a laminated body in one process substantially may be sufficient.

  For example, when a thermoplastic polyimide resin is used for the thermoplastic resin layer, a resin solution obtained by dissolving or dispersing the thermoplastic polyimide resin or a resin composition containing the thermoplastic polyimide resin in an organic solvent is applied to the surface of the heat resistant film. Although it may be applied, a solution of polyamic acid which is a precursor of thermoplastic polyimide may be prepared, applied to the surface of the heat resistant film, and then imidized. The conditions for synthesis of polyamic acid and imidization of polyamic acid at this time are not particularly limited, but conventionally known raw materials and conditions can be used (for example, see Examples described later). When the polyamic acid is fired, if it is overheated, tackiness can be lowered, but problems such as an increase in moisture absorption and deterioration of the film may occur. Further, the polyamic acid solution may contain, for example, a coupling agent or the like depending on the application.

  In addition, the thickness configuration of each layer according to the adhesive sheet in the present invention may be adjusted as appropriate so as to have a total thickness according to the application, but the linear expansion coefficient of each layer does not cause warpage in the state of the adhesive sheet. It is preferable to adjust the thickness balance of each thermoplastic resin layer while considering the above. When the difference in the linear expansion coefficient between the thermoplastic resin layers facing each other through the heat resistant film is small, it becomes easy to balance the thickness.

  Here, when manufacturing a single-sided metal-clad laminate, the adhesive sheet is a filler in this layer as described above for the purpose of controlling the adhesion strength with the protective material of the thermoplastic resin layer on the side where the metal foil is not laminated. It is preferable to contain. By reducing the surface tackiness, the adhesiveness is not substantially exhibited with respect to materials in the process such as a metal roll, a press plate, and a protective material at the time of thermocompression bonding. More specifically, it is possible to prevent contamination due to adhesion to these materials or partial transfer. In some cases, a non-thermoplastic resin may be used for the layer on which the metal foil is not laminated. In this case, however, the adhesiveness to the heat-resistant film is also lowered, so that it tends to be difficult to use as an adhesive sheet. . In general, the difference between the linear expansion coefficients of the non-thermoplastic resin and the thermoplastic resin is large, so that it is not easy to balance the linear expansion coefficient between the surface in contact with the metal foil and the surface not in contact with the metal foil during thermocompression bonding. Since the surface tackiness of the thermoplastic resin layer can be lowered simply by adding a filler, the same kind of resin can be used for both thermoplastic resin layers, and productivity can be improved.

  By suppressing the occurrence of warpage of the resulting adhesive sheet by adjusting the thickness balance between the thermoplastic resin layer and the backing layer as the adhesive layer, and the composition of the layer on which the metal foil is not laminated (backing layer) as described above It becomes possible. Specifically, when a rectangular adhesive sheet having a size of 7 cm wide × 20 cm long is produced, 20 ° C., 60% R.D. H. It is preferable that the warping of the four corners after leaving for 12 hours in this environment is 0.5 mm or less. If the warpage of the adhesive sheet is within the above range, it is possible to suppress the warpage of the wiring board after the circuit is formed by etching with respect to the single-sided metal-clad laminate produced using this. Mounting becomes easy.

Moreover, from the point which can suppress the curvature of the single-sided metal-clad laminated board when bonding metal foil to the adhesive sheet of this invention, the linear expansion coefficient (200-300 degreeC) of the whole adhesive sheet is the wire of metal foil. When the expansion coefficient (200 to 300 ° C.) is α ₀ (ppm / ° C.), it is preferably adjusted so as to be within the range of α ₀ ± 5 (ppm / ° C.). In addition, about the linear expansion coefficient of the whole adhesive sheet, it is possible to calculate by using the formula shown by Unexamined-Japanese-Patent No. 2000-174154, for example.

<Metal foil>
In the present invention, the metal foil is not particularly limited, but when the single-sided metal-clad laminate of the present invention is used for electronic equipment / electric equipment, for example, copper or copper alloy, stainless steel or alloy thereof And foil made of nickel or nickel alloy (including 42 alloy), aluminum or aluminum alloy. In general flexible laminates, copper foil such as rolled copper foil and electrolytic copper foil is frequently used, but it can also be preferably used in the present invention. In addition, the antirust layer, the heat-resistant layer, or the contact bonding layer may be apply | coated to the surface of these metal foil. Moreover, it does not specifically limit about the thickness of the said metal foil, According to the use, what is necessary is just the thickness which can exhibit a sufficient function.

<Method for producing single-sided metal-clad laminate>
The single-sided metal-clad laminate according to the present invention can be obtained by bonding a metal foil to a thermoplastic resin layer serving as an adhesive layer of the adhesive sheet by thermocompression bonding. Examples of the bonding method of the adhesive sheet and the metal foil include batch processing by a single plate press, continuous processing by a hot roll laminating apparatus or a double belt press (DBP) apparatus, and facilities including productivity and maintenance costs. From the viewpoint of cost, a method using a hot roll laminating apparatus having a pair of metal rolls is preferable. The “heat roll laminating apparatus having a pair of metal rolls” herein may be an apparatus having a metal roll for heating and pressurizing a material, and the specific apparatus configuration is particularly limited. It is not a thing.

  The specific configuration of the means for performing the thermocompression bonding is not particularly limited, but in order to improve the appearance of the obtained single-sided metal-clad laminate, it is bonded to a pressure surface (for example, a metal roll). It is preferable to arrange a protective material between the sheet and / or the metal foil. The protective material is not particularly limited as long as it can withstand the heating temperature in the thermocompression bonding process, and preferably a heat-resistant plastic such as a non-thermoplastic polyimide film, a metal foil such as a copper foil, an aluminum foil, or a SUS foil. Can be used. Among these, a non-thermoplastic polyimide film is more preferably used from the viewpoint of excellent balance between heat resistance and recyclability. In the thermocompression bonding step, for example, the adhesive strength between the protective material and the thermoplastic resin layer (backing layer) on the side where the metal foil is not laminated in the single-sided metal-clad laminate after passing through the hot roll is in the range of 0.05 to 5 N / cm. Preferably there is. If the adhesion strength is less than 0.05 N / cm, the protective material may not be able to withstand the shrinkage and may be peeled and wrinkled on the single-sided metal-clad laminate. On the other hand, if the adhesion strength is higher than 5 N / cm, stress may be applied to the single-sided metal-clad laminate at the time of peeling from the protective material, causing warpage or increasing the dimensional change rate.

  The heating method of the material to be laminated in the thermocompression bonding means is not particularly limited. For example, heating using a conventionally known method capable of heating at a predetermined temperature such as a heat circulation method, a hot air heating method, an induction heating method, or the like. Means can be used. Similarly, the method for pressurizing the material to be laminated in the thermocompression bonding means is not particularly limited. For example, a conventionally known method capable of applying a predetermined pressure such as a hydraulic method, a pneumatic method, a gap pressure method, etc. The pressurizing means adopting can be used.

  The heating temperature in the thermocompression bonding step, that is, the laminating temperature, is preferably a glass transition temperature (Tg) of the adhesive sheet used + 50 ° C. or higher, and more preferably Tg + 100 ° C. or higher of the adhesive sheet. If it is Tg + 50 degreeC or more, an adhesive sheet and metal foil can be favorably thermocompression bonded. Moreover, if it is Tg + 100 degreeC or more, the lamination speed | rate can be raised and the productivity can be improved more.

  The laminating speed in the thermocompression bonding step is preferably 0.5 m / min or more, and more preferably 1.0 m / min or more. If it is 0.5 m / min or more, sufficient thermocompression bonding is possible, and if it is 1.0 m / min or more, productivity can be further improved.

  The higher the pressure in the thermocompression bonding step, that is, the laminating pressure, there is an advantage that the laminating temperature can be lowered and the laminating speed can be increased, but in general, the single-sided metal-clad laminate obtained when the laminating pressure is too high is obtained. Dimensional changes tend to get worse. Conversely, if the lamination pressure is too low, the adhesive strength of the metal foil of the single-sided metal-clad laminate obtained tends to be low. Therefore, the laminating pressure is preferably in the range of 49 to 490 N / cm (5 to 50 kgf / cm), and more preferably in the range of 98 to 294 N / cm (10 to 30 kgf / cm). Within this range, the three conditions of the lamination temperature, the lamination speed and the lamination pressure can be made favorable, and the productivity can be further improved.

  In order to obtain the single-sided metal-clad laminate according to the present invention, it is preferable to use a hot roll laminating apparatus that continuously press-bonds the material to be laminated while heating. In addition, a layered material feeding unit for feeding the layered material may be provided, or a layered material winding unit for winding the layered material may be provided after the thermal laminating unit. By providing these means, the productivity of the hot roll laminating apparatus can be further improved. The specific configurations of the laminated material feeding means and the laminated material winding means are not particularly limited. For example, it is known that an adhesive sheet, a metal foil, or an obtained single-sided metal-clad laminate can be taken up. And a roll winder.

  Furthermore, it is more preferable to provide a protective material winding means and a protective material feeding means for winding and feeding the protective material. If these protective material take-up means and protective material feeding means are provided, the protective material can be reused by winding up the protective material once used in the thermocompression bonding step and installing it again on the feed-out side. . Further, when winding up the protective material, end position detecting means and winding position correcting means may be provided in order to align both ends of the protective material. As a result, the end portions of the protective material can be aligned and wound with high accuracy, so that the efficiency of reuse can be increased. The specific configurations of the protective material winding means, the protective material feeding means, the end position detecting means, and the winding position correcting means are not particularly limited, and various conventionally known devices can be used.

  By controlling the linear expansion coefficient of the entire adhesive sheet as described above, it is possible to suppress the warpage of the obtained single-sided metal-clad laminate. Specifically, when a rectangular single-sided metal-clad laminate having a size of 7 cm wide × 20 cm long is produced, 20 ° C., 60% R.D. H. It is preferable that the warping of the four corners after leaving for 12 hours in this environment is 1.0 mm or less. If the warpage of the single-sided metal-clad laminate is within the above range, it is possible to suppress warpage during conveyance in the process and warpage of the wiring board after circuit formation by etching.

  Next, the manufacturing method of the adhesive film which concerns on this invention is demonstrated in detail by an Example.

(Synthesis Example 1: Synthesis of polyamide acid precursor of thermoplastic polyimide)
To a glass flask having a capacity of 2000 ml, 780 g of N, N-dimethylformamide (DMF) and 115.6 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) were added, and a nitrogen atmosphere was added. 78.7 g of 3,3′4,4′-biphenyltetracarboxylic dianhydride (BPDA) was gradually added with stirring. Subsequently, 3.8 g of ethylenebis (trimellitic acid monoester acid anhydride) (TMEG) was added and stirred for 30 minutes in an ice bath. A solution in which 2.0 g of TMEG was dissolved in 20 g of DMF was separately prepared, and this was gradually added to the reaction solution while being careful of the viscosity and stirred. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution which is a precursor of thermoplastic polyimide.

Example 1
46.43 g of BAPP was dissolved in 546 g of DMF cooled to 10 ° C. To this, 9.12 g of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) was added and dissolved, and then 16.06 g of pyromellitic dianhydride (PMDA) was added. Stir for 30 minutes. After dissolving 18.37 g of p-phenylenediamine (p-PDA) in this solution, 37.67 g of PMDA was added and stirred for 1 hour to dissolve. Further, a DMF solution of PMDA (PMDA 1.85 g / DMF 24.6 g) prepared separately was carefully added to this solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of about 19% by weight and a rotational viscosity at 23 ° C. of 3400 poise.

  To 100 g of this polyamic acid solution, 50 g of a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was added, and the mixture was stirred and degassed at a temperature of 0 ° C. or less to obtain a comma. Using a coater, it was cast on aluminum foil. This resin film is heated at 130 ° C. for 120 seconds, and then the self-supporting gel film is peeled off from the aluminum foil (volatile content 45% by weight) and fixed to a metal frame, 250 ° C. × 20 seconds, 350 ° C. × 20 The film was dried and imidized at 450 ° C. for 20 seconds to obtain a heat-resistant film (non-thermoplastic polyimide film) having a thickness of 27 μm.

  Subsequently, the polyamic acid solution obtained in Synthesis Example 1 was diluted with DMF until the solid content concentration became 8% by weight. Polyamic acid was applied to one side of the heat resistant film using the DMF diluted solution so that the final thickness was 6 μm. Then, the thermoplastic resin layer used as an adhesive layer was formed in the single side | surface of a heat resistant film by heating at 160 degreeC for 1 minute.

  Further, a filler (Nippil E-1011 average particle size 3.5 μm, manufactured by Nippon Silica Kogyo Co., Ltd.) was added to the DMF diluted solution of the polyamic acid obtained in Synthesis Example 1 used above with respect to 100 parts by weight of the polyamic acid solid content. Then, this solution was applied to the uncoated surface of the heat-resistant film so that the final thickness was 7 μm. Then, it heated at 160 degreeC for 1 minute. Subsequently, heating was performed at 390 ° C. for 20 seconds to obtain an adhesive sheet. The linear expansion coefficient in the temperature range of 100 to 200 ° C. of this adhesive sheet was 20 ppm / ° C.

  Subsequently, a 9 μm-thick electrolytic copper foil (USLPR2 manufactured by Nihon Electrolytic Co., Ltd.), which is a metal foil, is brought into contact with the adhesive layer of the adhesive sheet thus prepared. A protective film (manufactured by Kaneka, Apical 125 NPI, linear expansion coefficient 16 ppm / ° C) is arranged on both sides of the hot roll laminating apparatus so that the laminating temperature is 380 ° C. Thermal lamination was performed under the conditions of a lamination pressure of 245 N / cm and a lamination speed of 1.5 m / min. Then, the single-sided metal-clad laminate concerning this invention was manufactured by isolate | separating the said protective film.

  As a result, there was no sticking to the transport rolls and the obtained single-sided metal-clad laminate did not warp. The adhesion strength between the backing layer of the single-sided metal-clad laminate and the protective film was 0.3 N / cm.

(Example 2)
In Example 1, the adhesive sheet was the same as Example 1 except that the filler was blended in the thermoplastic resin layer serving as the backing layer in a proportion of 3 parts by weight with respect to 100 parts by weight of the polyamic acid solid content. And a single-sided metal-clad laminate was produced.

  As a result, there was no sticking to the transport rolls and the obtained single-sided metal-clad laminate did not warp. The adhesion strength between the backing layer of the single-sided metal-clad laminate and the protective film was 4 N / cm.

(Example 3)
In Example 1, except that the filler was blended in a proportion of 50 parts by mass with respect to 100 parts by mass of the polyamic acid solid content in the thermoplastic resin layer (backing layer) on which the metal foil was not laminated, all other examples were the same as in Example 1. In the same manner as above, an adhesive sheet was produced to produce a single-sided metal-clad laminate.

  As a result, there was no sticking to the transport rolls and the obtained single-sided metal-clad laminate did not warp. The adhesion strength between the backing layer of the single-sided metal-clad laminate and the protective film was 0.05 N / cm.

(Comparative Example 1)
In Example 1, an adhesive sheet was produced in the same manner as in Example 1 except that no filler was added to the thermoplastic resin layer (backing layer) on which the metal foil was not laminated.

  When the adhesive sheet thus obtained is heat-laminated under the same conditions as in Example 1, the adhesive sheet is in close contact with the protective film and cannot be separated from the protective film to obtain a single-sided metal-clad laminate. could not.

(Comparative Example 2)
Example 1 is the same as Example 1 except that the thermoplastic resin layer (backing layer) in which the metal foil is not laminated is blended with a filler in a proportion of 1 part by weight with respect to 100 parts by weight of the polyamic acid solid content. Thus, an adhesive sheet was produced.

  When the adhesive sheet obtained in this manner is heat-laminated under the same conditions as in Example 1, the tackiness is not sufficiently lowered, and the backing layer adheres to the protective film to some extent. In the peeling process, warping occurred on the single-sided metal foil laminate. The adhesion strength between the backing layer of the single-sided metal-clad laminate and the protective film was 8 N / cm.

(Comparative Example 3)
Example 1 is the same as Example 1 except that the filler was blended in a proportion of 100 parts by weight with respect to 100 parts by weight of the polyamic acid solid content in the thermoplastic resin layer (backing layer) on which the metal foil is not laminated. Thus, an adhesive sheet was produced, and a single-sided metal-clad laminate was produced.

  When the adhesive sheet thus obtained is heat-laminated under the same conditions as in Example 1, the backing layer does not adhere to the protective film at all, the protective film and the adhesive sheet peel off, and the appearance is wrinkled. Only single-sided metal-clad laminates were obtained.

Claims (7)

  A method for producing a single-sided metal-clad laminate by thermocompression bonding a metal foil on one side of an adhesive sheet provided with a thermoplastic resin layer on both sides of a heat-resistant film, wherein the thermocompression bonding is a pressing surface of a thermocompression bonding apparatus. A protective material is disposed between the adhesive sheet and the adhesive sheet, and the adhesive strength between the thermoplastic resin layer on the side where the metal foil is not laminated and the protective material is in the range of 0.05 to 5 N / cm. A method for producing a single-sided metal-clad laminate.   The single-sided metal tension according to claim 1, wherein the adhesion strength between the thermoplastic resin layer on the side where the metal foil is not laminated and the protective material is controlled by containing a filler in the thermoplastic resin layer. A manufacturing method of a laminated board.   The method for producing a single-sided metal-clad laminate according to claim 1 or 2, wherein the heat-resistant film is a non-thermoplastic polyimide film.   The method for producing a single-sided metal-clad laminate according to any one of claims 1 to 3, wherein the thermoplastic resin layers provided on both surfaces of the heat-resistant film contain a thermoplastic polyimide resin.   The method for producing a single-sided metal-clad laminate according to claim 4, wherein each thermoplastic resin layer provided on both surfaces of the heat-resistant film contains the same kind of thermoplastic polyimide resin.   The method for producing a single-sided metal-clad laminate according to any one of claims 1 to 5, wherein the thermocompression bonding apparatus is a heat roll laminating apparatus having one or more pairs of metal rolls.   The method for producing a single-sided metal-clad laminate according to any one of claims 1 to 6, wherein the protective material is a non-thermoplastic polyimide film.