JP5405273B2 - Polyimide resin, and dry film, metal laminate and adhesive sheet using the same - Google Patents

Description

  The present invention relates to a polyimide resin, a dry film using the resin, a metal laminate, an adhesive sheet, and the like.

  Polyimide is excellent in heat resistance, chemical resistance, mechanical strength, electrical characteristics, and the like, and is therefore used in aircraft structural materials and cable coating materials. Polyimide is also often used as a heat-resistant adhesive in the electronic field such as flexible printed circuit boards and semiconductor packages.

  Such polyimide heat-resistant adhesives are required to have low-temperature adhesiveness in addition to heat resistance in processing. As a resin composition excellent in low-temperature adhesiveness, a resin composition composed of a polyimide resin having a siloxane unit, an epoxy resin, and a phosphate ester plasticizer has been proposed (see, for example, Patent Document 1). However, since components such as polyimide resin, epoxy resin, and plasticizer include aliphatic units, there is a problem that the thermal decomposition temperature is low.

  On the other hand, a composition containing a specific polyamic acid and a bismaleimide compound has been proposed as a resin composition having sufficient adhesive strength and heat resistance (see, for example, Patent Documents 2 to 4). However, in order to obtain adhesiveness, a temperature of 300 ° C. or higher may be required, and it does not have sufficient low-temperature adhesiveness.

  On the other hand, as an imide compound having a plurality of crosslinkable groups such as maleimide groups in a molecular chain, a compound having a skeleton in which benzene rings are bonded to each other with a methylene group has been proposed (see, for example, Patent Documents 5 and 6). ). However, these crosslinkable group-containing imide compounds are used for bonding metal to metal or bonding metal to resin, but are not used in combination with other polyimide resins.

  A resin composition composed of a specific bismaleimide compound and a polyamic acid has been proposed as a polyimide resin that improves low-temperature adhesion (see, for example, Patent Document 7). However, in a polyimide resin composition composed of a polyamic acid and a bismaleimide compound, the bismaleimide compound is crosslinked and thermally cured, but the polyimide itself is not crosslinked, so the increase in elastic modulus and linear expansion coefficient ( The reduction in CTE) was not sufficient. On the other hand, in recent years, the resin layer of the metal laminate is required to have higher solder heat resistance and dimensional stability.

  That is, in recent years, lead-free solder having a higher melting point than that in the past has been used in electronic component mounting. For this reason, the substrate is required to have high solder heat resistance. In particular, rigid flex, flexible multilayer substrates, and the like are insufficient in reliability at conventional solder heat resistance temperatures, and therefore are required to have solder heat resistance at higher temperatures.

  When a flexible substrate is used for a chip-on-film (COF), an inner lead bonder or a flip chip bonder is used to connect the chip and the metal wiring at a high temperature of 300 ° C. or higher by Au—Au bonding or Au—Sn bonding. To do. For this reason, the flexible substrate used for COF is required to have high solder heat resistance that does not deform even at high temperatures. Further, in addition to the thinning of the flexible substrate, the density of the wiring has been increased, and the distance between the metal wirings has been reduced. For this reason, when the flexible substrate is processed (joined or the like) at a high temperature, problems such as contact between metal wirings due to deformation of the resin layer or the like are likely to occur. For this reason, the flexible substrate is required to have high dimensional stability.

  In addition, the resin layer of such a flexible substrate has a laminated structure in order to have multiple functions such as adhesiveness and dimensional accuracy, but this requires a complicated manufacturing process and simplifies the base material configuration. There is a demand for polyimide resins that can be used.

JP-A-10-212468 JP-A-1-289862 JP-A-6-145638 Japanese Patent Laid-Open No. 6-192939 JP-A-62-131030 JP-A-63-88178 Japanese Patent Laid-Open No. 2004-209962

  However, a resin composition that has solder heat resistance and dimensional stability that satisfies the above-mentioned requirements while having low-temperature adhesiveness, and that can achieve a simplified base material configuration has not yet been proposed. The present invention has been made in view of such circumstances, while maintaining adhesiveness under relatively low temperature thermocompression bonding conditions (having low temperature adhesiveness), and having high solder heat resistance and dimensional stability. It aims at providing the polyimide resin composition which has this.

〔式（１）におけるＡ_１は、

（Ｒ_１〜４は、それぞれ同一であっても異なっていてもよく、水素原子、ハロゲン原子、炭素数１〜３のアルキル基から選ばれ；Ｒ_５は、−Ｏ−、−Ｓ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−ＣＯ−から選ばれ；Ｒ_６は水素原子、フェニル基から選ばれる）のいずれかで表され；
式（１）におけるＸ_１、Ｘ_２、Ｘ_３は、それぞれ同一であっても異なっていてもよく、直結、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−ＮＨＣＯ−から選ばれ；
式（１）におけるＢ_１は、

（Ｙ_１〜６は、同一であっても異なっていてもよく、直結、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−ＮＨＣＯ−から選ばれる）のいずれかで表される〕 The first of the present invention relates to the following polyimide resin.
[1] A polyimide resin having a structural unit represented by the following general formula (1).

[A ₁ in Formula (1) is

_{(R 1 to 4} may each have the same or different and a hydrogen atom, a halogen atom, selected from alkyl groups of 1 to 3 carbon atoms; _{R 5} is, -O -, - S -, - Selected from CH ₂ —, —C (CH ₃ ) ₂ —, —CO—; R ₆ is selected from a hydrogen atom and a phenyl group;
X ₁ , X ₂ and X ₃ in the formula (1) may be the same or different, and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —SO ₂ —, —NHCO—;
B ₁ in the formula (1) is

(Y _1-6 may be the same or different and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) _2- , -SO _2- , or -NHCO-]

（式（２）におけるＡ_２は、

から選ばれ；
式（２）におけるＢ_１は、式（１）におけるＢ_１と同様に定義される）
[2] The polyimide resin according to [1], wherein the structural unit is a structural unit represented by the following general formula (2).

(A ₂ in Formula (2) is

Chosen from;
B ₁ in formula (2) is defined in the same manner as B ₁ in formula (1))

（式（３）におけるＡ_２は、式（２）におけるＡ_２と同様に定義され；
式（３）におけるＢ_２は、

から選ばれる） [3] The polyimide resin according to [2], wherein the structural unit is a structural unit represented by the following general formula (3).

(A ₂ in formula (3) is defined in the same manner as A ₂ in formula (2);
B ₂ in the formula (3) is

Selected from)

  [4] The polyimide resin according to any one of [1] to [3], wherein the glass transition temperature is in the range of 100 ° C. or higher and 300 ° C. or lower.

〔式（４）におけるＡ_１は、

（Ｒ_１〜４は、それぞれ同一であっても異なっていてもよく、水素原子、ハロゲン原子、炭素数１〜３のアルキル基から選ばれ；Ｒ_５は、−Ｏ−、−Ｓ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−ＣＯ−から選ばれ；Ｒ_６は水素原子、フェニル基から選ばれる）のいずれかで表され；
式（４）におけるＸ_１、Ｘ_２、Ｘ_３は、それぞれ同一であっても異なっていてもよく、直結、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−ＮＨＣＯ−から選ばれ；
式（４）におけるＢ_１は、

（Ｙ_１〜６は、同一であっても異なっていてもよく、直結、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、−ＳＯ_２−、−ＮＨＣＯ−から選ばれる）のいずれかで表される〕 The second of the present invention relates to the polyamic acid shown below.
[5] A polyamic acid having a structural unit represented by the following general formula (4).

[A ₁ in Formula (4) is

_{(R 1 to 4} may each have the same or different and a hydrogen atom, a halogen atom, selected from alkyl groups of 1 to 3 carbon atoms; _{R 5} is, -O -, - S -, - Selected from CH ₂ —, —C (CH ₃ ) ₂ —, —CO—; R ₆ is selected from a hydrogen atom and a phenyl group;
X ₁ , X ₂ and X ₃ in the formula (4) may be the same or different, and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —SO ₂ —, —NHCO—;
B ₁ in the formula (4) is

(Y _1-6 may be the same or different and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) _2- , -SO _2- , or -NHCO-]

（式（５）におけるＡ_２は、

から選ばれ；
式（５）におけるＢ_１は、式（１）におけるＢ_１と同様に定義される） [6] The polyamic acid according to [5], wherein the structural unit is a structural unit represented by the following general formula (5).

(A ₂ in Formula (5) is

Chosen from;
B ₁ in formula (5) is defined in the same manner as B ₁ in formula (1))

（式（６）におけるＡ_２は、式（２）におけるＡ_２と同様に定義され；
式（６）におけるＢ_２は、

から選ばれる） [7] The polyamic acid according to [6], wherein the structural unit is a structural unit represented by the following general formula (6).

(A ₂ in formula (6) is defined in the same manner as A ₂ in formula (2);
B ₂ in the formula (6) is

Selected from)

The third of the present invention relates to the following dry film, metal laminate or adhesive sheet.
[8] A dry film obtained from the polyimide resin according to any one of [1] to [4].
[9] A metal laminate having a metal layer and a resin layer, wherein the resin layer has at least one layer containing a cured product of the polyimide resin according to any one of [1] to [4]. Laminated body.
[10] The resin layer of the metal laminate is a single layer containing a cured product of the polyimide resin according to any one of [1] to [4]. [9] The metal laminate according to [9].
[11] The metal laminate includes a polyimide film, a polyimide layer formed on one or both sides of the polyimide film, and a metal layer laminated on the polyimide layer formed on one or both sides: the metal The metal laminate according to [9], wherein the polyimide layer in contact with the layer is a layer containing a cured product of the polyimide resin according to any one of [1] to [4].
[12] In [9] to [11], the resin layer of the metal laminate includes a layer containing a cured product of the polyimide resin according to any one of [1] to [4] impregnated in a glass cloth. The metal laminate according to the description.
[13] An adhesive sheet having at least one adhesive layer containing the polyimide resin according to any one of [1] to [4].
[14] The adhesive sheet according to [13], comprising a single layer containing the polyimide resin according to any one of [1] to [4].
[15] The adhesive sheet according to [13] or [14], having an adhesive layer containing the polyimide resin according to any one of [1] to [4] impregnated in a glass cloth.

  According to the present invention, it is possible to provide a polyimide resin composition that can be bonded under relatively low temperature thermocompression bonding conditions (having low temperature bonding ability) and has high solder heat resistance and dimensional stability after curing. For this reason, a polyimide resin composition is preferably applicable as an adhesive for flexible printed circuit boards, for example.

1. Polyimide resin The polyimide resin of the present invention exhibits good adhesiveness by having a low elastic modulus in a relatively low bonding temperature region; it has an excellent elastic modulus after being cured in a high temperature region. Excellent solder heat resistance and dimensional stability.

The polyimide resin of the present invention has at least a structural unit (repeating unit) represented by the general formula (1).

The repeating unit represented by the general formula (1) is composed of a group derived from a diamine represented by the general formula (7) and a tetracarboxylic dianhydride represented by the general formula (8).

X _{1 to} X ₃ in the general formulas (1) and (7) may be the same as or different from each other, and are directly connected, —O—, —S—, —CO—, —COO—, —C ( CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —SO ₂ —, or —NHCO— is shown; from the viewpoint of imparting low-temperature adhesion to the resulting polyimide, etc., —O—, —S—, — CO- is preferred. The asymmetrical linking group —COO— or —NHCO— represents —C (═O) O— and —OC (═O) —, and —NHC (═O) — and —C (═O) NH—. means.

The imide group containing A ₁ in the general formulas (1) and (7) may be bonded to any carbon of the phenyl ring; however, preferably, the para position or the meta position with respect to the bonding position of X ₂ Is bound to.

The imide group containing B ₁ of the repeating unit represented by the general formula (1) may be bonded to any carbon of the phenyl ring; however, preferably, with respect to the bonding position of X ₁ or X ₃ Bonded to the meta or para position.

For example, the repeating unit represented by the general formula (1) is preferably a unit synthesized from a diamine represented by the general formula (9).

A ₁ in the general formulas (1), (7), and (9) may be a divalent group represented by the following formula.

Here, R _1-4 may be the same or different from each other; it is selected from a hydrogen atom, a halogen atom, and an alkyl group having 1 to 3 carbon atoms. R ₅ is selected from —O—, —S—, —CH ₂ —, —C (CH ₃ ) ₂ —, and —CO—. R ₆ is selected from a hydrogen atom and a phenyl group. The group represented by formula (1-1) is preferably represented by formula (1-4) in which R ₁ and R ₂ are hydrogen atoms; the group represented by formula (1-2) is preferably R _3. And a group represented by the formula (1-5) wherein R ₄ is a hydrogen atom and R ₅ is methylene; in the group represented by the formula (1-3), R ₆ is preferably a hydrogen atom or a phenyl group It is represented by Formula (1-6) or Formula (1-7).

Thus, A ₁ in the general formula (1) is characterized by containing a thermally crosslinkable group. A ₁ in the general formula (1) can be appropriately selected depending on the physical properties required for the polyimide of the present invention. For example, the polyimide resin of the present invention may be required to have solubility in a solvent and crosslinking performance suitable for the processing conditions of the resin. In particular, it is necessary to select a group that crosslinks at an appropriate temperature according to the processing conditions of the resin. For example, in the case of the group represented by the formula (1-4), since it becomes a polyimide that crosslinks at low temperature conditions, it is easy to process at low temperature; in the case of the group represented by the formula (1-7), Since it becomes a cross-linked polyimide, it is easy to process at high temperature.

On the other hand, B ₁ in the general formulas (1) and (8) is selected from tetravalent groups represented by the following formulas. Y _{1 to} Y ₆ in the following formulas are each a single bond, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —SO. _2- or -NHCO-. The asymmetrical linking group —COO— or —NHCO— represents —C (═O) O— and —OC (═O) —, and —NHC (═O) — and —C (═O) NH—. means.

B ₁ in the general formula (1) may be a tetravalent group derived from a tetracarboxylic dianhydride represented by the general formula (8). Examples of the tetracarboxylic dianhydride represented by the general formula (8) include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, bis (3,4-di Carboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (3, 4-Dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-Dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-di Carboxymethyl aminophenoxy) biphenyl dianhydride, and the like 2,2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride. Of these, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride and the like are preferable.

  The tetracarboxylic acid unit in a part of the structural units represented by the general formula (1) in the polyimide resin is a tetracarboxylic acid other than the tetracarboxylic dianhydride represented by the general formula (8). It may be a unit derived from an acid dianhydride. One or more or two or more units derived from other tetracarboxylic dianhydrides may be contained in the polyimide resin. Thereby, the performance of polyimide resin can be improved or modified.

  Examples of other tetracarboxylic dianhydrides include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 1,1-bis (2,3-dicarboxyl Phenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3, 6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride and the like are included. These other tetracarboxylic dianhydrides may be used alone or in combination of two or more. In addition, a tetracarboxylic dianhydride in which some or all of the hydrogen atoms on the aromatic ring of these other tetracarboxylic dianhydrides are substituted with a group selected from the group consisting of a fluoro group or a trifluoromethyl group. There may be.

  In addition, the polyimide having the repeating unit represented by the general formula (1) includes one or more repeating units other than the repeating unit represented by the general formula (1) as long as desired physical properties and the like are not impaired. It may be. Thereby, the performance of polyimide resin can be improved or modified. Other polyimide units may be included as a copolymerization component or may be included as other blended polyimides.

  The polyimide resin may contain a thermoplastic resin or a thermosetting resin other than polyimide as long as the object of the present invention is not impaired.

  Examples of thermoplastic resins include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polybutadiene, polystyrene, polyvinyl acetate, ABS resin, polybutylene terephthalate, polyethylene terephthalate, polyphenylene oxide, polycarbonate, PTFE, celluloid, polyarylate, Examples include polyether nitrile, polyamide, polysulfone, polyether sulfone, polyether ketone, polyphenylene sulfide, polyamide imide, polyether imide, modified polyphenylene oxide, and polyimide. Examples of the thermosetting resin include thermosetting polybutadiene, formaldehyde resin, amino resin, polyurethane, silicone resin, SBR, NBR, unsaturated polyester, epoxy resin, polycyanate, phenol resin, and polybismaleimide. These resins may be used alone or in combination of two or more according to the purpose. A method of blending or alloying a plurality of types of resins is not particularly limited, and a known method can be applied.

  The polyimide resin may further contain other components as long as the object of the present invention is not impaired. For example, a metal catalyst containing gallium, germanium, indium or lead to control (accelerate or suppress) the crosslinking reaction rate of the polyimide resin that proceeds by heat treatment; molybdenum, manganese, nickel, cadmium, cobalt, chromium, iron, Transition metal catalysts containing copper, tin, platinum or the like; phosphorus compounds, silicon compounds, nitrogen compounds, sulfur compounds and the like may also be included. In addition, in order to control the crosslinking reaction rate, the polyimide resin is irradiated with radiation such as infrared rays, ultraviolet rays, α, β and γ rays, electron beams or X-rays, plasma treatment, doping treatment, etc. Also good.

  The polyimide resin may further contain a filler or an additive as long as the object of the present invention is not impaired. Examples of fillers or additives include wear resistance improvers such as graphite, carborundum, silica stone powder, molybdenum disulfide, and fluorine resins; flame retardant improvers such as antimony trioxide, magnesium carbonate, and calcium carbonate; Electrical property improvers such as clay and mica; Tracking resistance improvers such as asbestos, silica and graphite; Acid resistance improvers such as barium sulfate, silica and calcium metasilicate; Iron powder, zinc powder, aluminum powder, copper powder, etc. In addition, glass beads, glass spheres, talc, diatomaceous earth, alumina, shirasu balun, hydrated alumina, metal oxides, colorants and pigments are included. These fillers or additives may be used alone or in combination of two or more.

  When the polyimide resin composition is used as an adhesive layer of a laminate for a flexible circuit board or an adhesive resin layer of an adhesive sheet, the glass transition temperature of the polyimide resin composition may be 100 ° C. or higher and 300 ° C. or lower. preferable. In particular, in order to improve low temperature adhesiveness, the glass transition temperature of the polyimide resin composition is more preferably 100 ° C. or higher and 240 ° C. or lower, and further preferably 100 ° C. or higher and 200 ° C. or lower.

The elastic modulus at the time of plasticization of the polyimide resin composition is preferably 1 × 10 ³ Pa or more and 1 × 10 ⁷ Pa or less; moreover, to improve the embeddability to the adherend and obtain good adhesiveness More preferably, the pressure is 1 × 10 ⁴ Pa or more and 1 × 10 ⁶ Pa or less.

  The elastic modulus at the time of plasticization is measured as follows, for example. An uncrosslinked film is obtained by baking the precursor varnish of the polyimide resin composition at 240 ° C. for 30 minutes after film casting. The elastic modulus of the obtained uncrosslinked film is measured up to 400 ° C. in a tensile mode and 1 Hz in a nitrogen atmosphere using RSA-III manufactured by TA Instruments. The minimum value of the elastic modulus observed in this temperature range is defined as the elastic modulus during plasticization (E'min).

  Conventional polyimide resin compositions, for example, resin compositions containing polyimide and a bismaleimide compound, exhibit a low elastic modulus in a relatively low temperature range, and achieve a certain degree of elastic modulus improvement by heating and crosslinking. It had been. However, when a bismaleimide compound is combined, the bismaleimide compounds are cross-linked and the polyimide itself is not cross-linked. On the other hand, in the polyimide resin of the present invention, since polyimides form a crosslinked structure, physical properties such as elastic modulus, CTE, and glass transition temperature after crosslinking can be changed efficiently.

  Moreover, since the polyimide of the polyimide resin of the present invention contains a thermally crosslinkable group in the repeating unit, the number of introduced crosslinkable groups is larger than when a crosslinkable group is introduced only at the molecular end. Thus, a very high crosslink density can be achieved.

  Furthermore, since it does not contain a low molecular compound such as a bismaleimide compound, the production line is not contaminated by the volatilization of the low molecular compound in the manufacturing process at a high temperature.

  As a result, when the polyimide resin of the present invention is applied to the resin layer in contact with the metal layer of the metal laminate, the resin layer and the metal layer can be bonded well at a relatively low temperature; The deformation and dimensional change of the resin layer are effectively suppressed.

2. Polyamic acid varnish The polyamic acid varnish of the present invention is a varnish containing a precursor of the polyimide resin. The polyamic acid varnish contains a polyamic acid containing a structural unit (repeating unit) represented by the general formula (4) and, if necessary, a solvent.

Formula _A 1 in (4), _{B 1} and _X 1 to X ₃ are defined as in _A 1, _{B 1} and _X 1 to X ₃ in the general formula (1).

  The logarithmic viscosity ηinh of the N, N-dimethylacetamide solution containing polyamic acid at a concentration of 0.5 g / dl is preferably 0.2 to 2.0 dl / g; 0.3 to 1.0 dl / g More preferably, it is more preferably 0.4 to 0.9 dl / g. The logarithmic viscosity ηinh can be measured using, for example, an Ubbelohde viscosity tube.

  When the logarithmic viscosity of the polyamic acid is within the above range, it becomes easy to make the thickness of the coating film uniform in the polyamic acid varnish coating process when a film or a metal laminate is produced. Moreover, the intensity | strength of the resin composition obtained by imidating the coating film of a polyamic-acid varnish can be raised, and it becomes easy to shape | mold as a film or a metal laminated body.

  The polyamic acid varnish may preferably contain a solvent in order to uniformly mix the polyamic acid and other components or to adjust the viscosity to an appropriate viscosity. The solvent is not particularly limited, but is preferably an aprotic polar solvent, and more preferably an aprotic amide solvent. Examples of aprotic amide solvents include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone and the like are included.

  The polyamic acid varnish may further contain another solvent as necessary. Examples of such other solvents include benzene, toluene, o-xylene, m-xylene, p-xylene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-bromotoluene, m-bromo. Toluene, p-bromotoluene, chlorobenzene, bromobenzene and the like are included. These other solvents may be contained alone or in combination of two or more.

  The viscosity of the polyamic acid varnish of the present invention at 25 ° C. measured with an E-type viscometer is not particularly limited, but it should be in the range of 100 to 20000 mPa · S from the viewpoint of easy control of the coating thickness. preferable.

  The polyamic acid varnish may contain other optional components as necessary, like the polyimide resin.

3. The manufacturing method of a polyimide resin composition The manufacturing method of a polyimide resin composition may be obtained by heating and imidizing the polyamic acid containing the repeating unit represented by General formula (4). The polyamic acid containing the repeating unit represented by the general formula (4) includes, for example, a diamine represented by the general formula (7) and a tetracarboxylic dianhydride represented by the general formula (8). It can be obtained by polycondensation reaction. The charge ratio of diamine to tetracarboxylic dianhydride in the polycondensation reaction preferably satisfies the following formula (A).
M1: M2 = 0.000 to 1.00: 1.00 Formula (A)
(M1: number of moles of tetracarboxylic dianhydride, M2: number of moles of diamine)

  M1: M2 is preferably 0.92 to 1.00: 1.00; more preferably 0.95 to 1.00: 1.00; 0.97 to 1.00: 1. More preferably, it is 00. By adjusting the charging ratio in such a range, the molecular weight can be adjusted, the characteristics of the polyimide can be sufficiently extracted, and the handling becomes easy.

Except for the case of M1: M2 = 1, when the charging ratio is set within the above range, the acid anhydride group is completely consumed and the molecular end of the polyimide becomes an amino group. This amino terminal amino group is preferably end-capped by reaction with the compound represented by formula (10).

D in the general formula (10) is not particularly limited, but is preferably selected from the groups represented by the following formula.

Here, _R1-4 are each independently selected from a hydrogen atom, a halogen atom, and an alkyl group having 1 to 3 carbon atoms. R ₅ is selected from —O—, —S—, —CH ₂ —, —C (CH ₃ ) ₂ —, and —CO—. R ₆ is selected from a hydrogen atom and a phenyl group.

  When the molecular terminal of the polyamic acid is sealed, the reaction between the terminal group (especially terminal amino group) of the polyimide obtained by dehydration and ring closure and the carbonyl group in the polyimide molecular structure can be suppressed. By suppressing the reaction, the elastic modulus of the resin when the polyimide resin is heated and plasticized (that is, at a low temperature) can be sufficiently lowered. Therefore, for example, when a polyimide resin composition is laminated on a metal foil and heated to obtain a metal laminate, the heated polyimide resin composition is efficiently embedded in the irregularities of the metal foil, and high adhesion can be obtained. . Moreover, said terminal group also has crosslinking reactivity. Therefore, the elastic modulus of the cured product of the polyimide resin composition can be increased and the linear expansion coefficient can be reduced.

  To imidize by heating the polyamic acid, first, the solvent is removed at a temperature at which the crosslinking reaction of the thermally crosslinkable group contained in the structural unit (repeating unit) represented by the general formula (4) does not occur. Further, the polyamic acid is imidized (ring closure). The heating temperature for imidization is, for example, about 100 to 300 ° C., and the heating time is, for example, about 3 minutes to 12 hours. The imidization is usually performed at atmospheric pressure, but may be performed under pressure. The atmosphere when imidizing is not particularly limited, but is usually air, nitrogen, helium, neon, argon, or the like, preferably nitrogen or argon which is an inert gas.

4). Use of polyimide resin The polyimide resin of the present invention is used in various applications, but is suitably applied to applications requiring low temperature adhesion and dimensional stability during high temperature processing, such as dry films, adhesive sheets, metal laminates, etc. Can be done.

1) Dry film The dry film of the present invention contains the polyimide resin of the present invention. The dry film can be obtained, for example, by applying the polyamic acid varnish on a substrate, removing the solvent and imidizing, and then peeling the obtained film from the substrate. Solvent removal and imidation of the polyamic acid varnish are not particularly limited, but are preferably performed under reduced pressure or in an inert atmosphere such as nitrogen, helium, or argon.

  As described above, the heating temperature is a temperature at which the thermally crosslinkable group contained in the repeating unit of the polyamic acid does not undergo a crosslinking reaction, and may be a temperature at which the imidization reaction proceeds at a temperature equal to or higher than the boiling point of the solvent. For example, in the case of a polyamic acid synthesized in an aprotic amide solvent, the heating temperature for desolvation and imidization may be about 100 to 300 ° C., and the heating time is not particularly limited, Usually, it may be about 3 minutes to 12 hours.

  Examples of the substrate on which the polyamic acid varnish is applied include inorganic substrates such as metal foil and glass; various resin films and the like. The thickness of the coating film of the polyamic acid varnish is preferably adjusted so that the film thickness after solvent removal and imidization is 1 mm or less, although it depends on the solid content concentration of the polyamic acid varnish.

  Examples of the means for applying the polyamic acid varnish include general application means such as a roll coater, a die coater, a gravure coater, a dip coater, a spray coater, a comma coater, a curtain coater, and a bar coater. These application means are appropriately selected depending on the viscosity of the polyamic acid varnish and the coating film thickness.

  Examples of the means for drying the polyamic acid varnish include electric heating or oil heated hot air, a roll support using infrared rays as a heat source, an air float type drying furnace, and the like. In order to prevent deterioration of the polyimide resin or discoloration due to oxidation of the metal foil, the dry atmosphere may be replaced with a gas other than air, such as nitrogen, argon, or hydrogen.

2) Adhesive sheet The adhesive sheet of this invention has the contact bonding layer containing the polyimide resin of this invention. Furthermore, the adhesive sheet preferably has a base resin film and an adhesive layer formed on one or both sides thereof, and the adhesive layer preferably contains the polyimide resin of the present invention.

  The base resin film is not particularly limited, but is preferably a polyimide film. Examples of the polyimide film include a film obtained by applying and drying a non-thermoplastic polyimide precursor varnish, a commercially available non-thermoplastic polyimide film, and the like. Specifically, Upilex S, Upilex SGA, Upilex SN (manufactured by Ube Industries, registered trademark / product name), Kapton H, Kapton V, Kapton EN (manufactured by Toray DuPont, registered trademark / product name), Apical AH, Apical NPI, Apical HP (manufactured by Kaneka Corporation, registered trademark / trade name) and the like are included.

  The adhesive sheet is obtained, for example, by applying a polyamic acid varnish on a base resin film, drying, and imidizing as necessary. The method of application | coating and drying can be performed similarly to the case of a dry film. The thickness of the adhesive layer is preferably 1 mm or less.

  The adhesive sheet of the present invention may be a dry film composed of a single layer containing the polyimide resin of the present invention. The manufacturing cost of the single-layer adhesive sheet can be reduced.

  The adhesive sheet of the present invention may have a layer containing a polyimide resin impregnated in a glass cloth. By impregnating a glass cloth with a polyimide resin, a higher elastic modulus and a lower CTE can be obtained.

3) Metal laminate The metal laminate of the present invention has a metal layer and a resin layer; at least one layer of the resin layer is a layer containing a cured product of the polyimide resin of the present invention.

  The metal layer of the metal laminate is not particularly limited, but may be a metal selected from copper, copper alloy, stainless steel, stainless steel alloy, nickel, nickel alloy (including 42 alloy), aluminum, aluminum alloy, and the like. preferable. Especially, it is more preferable that a metal layer is copper, a copper alloy, or stainless steel foil. The metal layer may be a metal foil or may be formed on the resin layer by a sputtering method or the like.

  The thickness of the metal layer of the metal laminate is not particularly limited as long as it can be used in a reel shape, but is preferably 0.1 μm or more and 150 μm or less; more preferably 2 μm or more and 150 μm or less; 3 μm or more More preferably, it is 50 μm or less; more preferably 3 μm or more and 35 μm or less; and most preferably 3 μm or more and 12 μm or less.

  The resin layer of the metal laminate is preferably a polyimide layer. The resin layer may be a single layer or a multilayer. When the resin layer is a multilayer polyimide layer, the components of the adjacent polyimide layers are preferably different from each other. That the components of the adjacent polyimide layers are different from each other specifically means that the components and compositions of the monomers are different. In addition, at least one of the single-layer polyimide layer or the multilayer polyimide layer may include a resin composition (mixture) made of two or more different polyimides.

  When the resin layer of the metal laminate is a multilayer polyimide layer, for example, it has a polyimide film and a polyimide layer formed on one or both sides of the polyimide film. Of these, the polyimide layer in contact with the metal layer is preferably a layer containing a cured product of the polyimide resin of the present invention. Specifically, the cured product of the polyimide resin of the present invention is a cured product obtained by crosslinking reaction of the thermally crosslinkable group contained in the structural unit represented by the general formula (1) of the polyimide resin. preferable. The layer containing the cured product of the polyimide resin of the present invention is excellent in adhesion to the metal layer.

  The thickness of the polyimide layer in contact with the metal layer is preferably 0.1 μm or more and 20 μm or less; more preferably 0.1 μm or more and 10 μm or less; and further preferably 0.1 μm or more and 5 μm or less. If the total thickness of the polyimide layer becomes too large, the rigidity becomes high, so that it is not suitable for applications requiring folding resistance and the like; on the other hand, if it is too thin, the insulating properties and handling properties are lowered. For this reason, the total thickness of the resin layer of the metal laminate is preferably 3 μm or more and 75 μm or less, and more preferably 10 μm or more and 45 μm or less. When the thickness of the polyimide layer is within the above range, the metal laminate tends to be excellent in insulation, flexibility and workability and at low cost.

  The polyimide film in the resin layer of the metal laminate is the same as the polyimide film described above. When a commercially available non-thermoplastic polyimide film is used as the polyimide film, the film thickness is usually 3 μm or more and 75 μm or less, preferably 7.5 μm or more and 40 μm or less. When a film obtained by applying and drying a precursor varnish of non-thermoplastic polyimide is used as the polyimide film, the film thickness is 0.1 μm or more and 40 μm or less; preferably 0.5 μm or more and 25 μm or less; more preferably 0 .5 μm or more and 16 μm or less. The surface of these polyimide films may be subjected to plasma treatment, corona discharge treatment or the like.

  The resin layer of the metal laminate may be a single layer made of the polyimide resin of the present invention. If the resin layer is a single layer, the manufacturing cost is greatly reduced. Moreover, the resin layer of a metal laminated body may have a layer containing the hardened | cured material of the polyimide resin of this invention which impregnated the glass cloth.

Although the polyimide metal laminated body of this invention is not restrict | limited in particular, For example, it can be manufactured with the following method.
(1) A method of thermocompression bonding a dry film containing the polyimide resin of the present invention and a metal foil.
(2) A method of applying and drying the polyamic acid varnish (polyimide precursor varnish) of the present invention on a metal foil and further imidizing.

  The dry film used in (1) may have a single-layer polyimide layer or a multilayer polyimide layer. When the dry film has a multilayer polyimide layer, at least the polyimide layer in contact with the metal foil only needs to contain the polyimide resin of the present invention.

  Examples of the method of thermocompression bonding in the method of (1) include a metal roll heated by heating or dielectric heating using oil or the like, or between rolls whose surfaces are lined with rubber or the like. And laminating method; hot pressing method and the like. The method of laminating is suitable for the production of continuous roll products; the method of hot pressing is suitable for the production of cut sheet-like single sheets, and can be appropriately selected depending on the application.

  The atmosphere gas at the time of thermocompression bonding is, for example, air, nitrogen, argon or the like. The heating temperature is a temperature mainly corresponding to the glass transition temperature of the thermoplastic polyimide, and is usually 100 to 400 ° C, preferably 150 to 300 ° C. The heating time is, for example, 0.01 seconds to 15 hours. The heating pressure may be, for example, 0.1 to 30 MPa, and preferably 0.5 to 10 MPa.

  In order to further enhance the adhesion between the metal foil and the polyimide layer, post-treatment may be performed using an autoclave or the like. The post-treatment temperature is usually 150 to 400 ° C., preferably 200 to 350 ° C .; the post-treatment time is 1 minute to 50 hours; the treatment pressure is normal pressure to 3 MPa. In order to prevent oxidation of the metal foil, it is preferable to replace the inside of the autoclave apparatus with a vacuum or an inert gas such as nitrogen or argon.

  The drying temperature of the polyamic acid varnish coating film in the method (2) may be in the temperature range of 60 to 600 ° C., but it is preferable to raise the temperature stepwise. By raising the coating temperature stepwise and drying, it is possible to obtain a polyimide layer having a uniform film thickness and excellent dimensional stability without causing problems such as foaming or formation of crushed skin. . The drying time may be appropriately set in the range of 0.05 to 500 minutes. As the means for applying and drying the polyamide acid varnish, the same ones as described above can be used.

  The double-sided metal laminate in which the metal foil is laminated on both sides of the resin layer can be produced by either method (1) or (2), and can also be produced by a method combining (1) and (2). For example, a single-sided metal laminate (i) obtained by thermocompression bonding a dry film and a metal foil according to the method (1) is prepared; a polyamic acid varnish is applied to the metal foil according to the method (2) A single-sided metal laminate (ii) obtained by drying and imidization is prepared. And a double-sided metal laminated body can be obtained by heat-pressing and laminating the dry film surface of a single-sided metal laminated body (i), and the polyimide surface of a single-sided metal laminated body (ii).

  Thus, by making the polyimide layer in contact with the metal layer in the metal laminate into a layer containing the polyimide resin of the present invention, the metal layer and the polyimide layer can be favorably bonded at a relatively low temperature. For this reason, even if it does not become high processing temperature, a laminated board which has high adhesive strength can be obtained, without a void remaining in the interface of a metal layer and a polyimide layer.

  Furthermore, the elastic modulus of the cured product of the polyimide resin of the present invention is high. Therefore, the metal laminate having a layer containing a cured product of the polyimide resin of the present invention may cause solder blistering even when used as an electric wiring board in an LSI chip or a component mounting process, a repair process, etc., where the operating temperature conditions are severe. It is suppressed. Furthermore, the metal laminate having a layer containing a cured product of the polyimide resin is less susceptible to deformation and dimensional change at high temperatures, so that the wiring generated as the electric wiring board becomes thinner and the wiring density increases. Short circuit etc. can be suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this. Abbreviations of compounds used in Examples and Comparative Examples are as follows.

[solvent]
NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide [diamine]
TrisAPB: 1,3,5-tri (3-aminophenoxy) benzene APB: 1,3-bis (3-aminophenoxy) benzene [tetracarboxylic dianhydride]
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride PEPA: 4-phenylethynyl phthalic anhydride

(Synthesis Example 1)
Synthesis of Thermally Crosslinkable Group-Introduced Diamine In a vessel equipped with a stirrer, Dean-Stark trap and nitrogen introduction tube, 150 g of NMP was charged as a solvent, and subsequently 30.0 g of TrisAPB was charged and stirred at room temperature for dissolution. To this solution, 18.6 g of PEPA was charged and stirred at room temperature for 1 hour. Subsequently, 150 g of xylene was added, and the mixture was further heated for 6 hours while being azeotropically dehydrated by heating in an oil bath at 180 ° C. Thereafter, xylene was removed by heating, and the obtained NMP solution was poured into water. The precipitate was separated by filtration, dissolved in acetone, poured into water again and washed. The precipitate was filtered and dried under reduced pressure to obtain a mixture containing the target product. The obtained crude product was dissolved in acetonitrile, the insoluble part was removed, and the residue was purified by column chromatography (eluent: chloroform → chloroform / ethyl acetate). Was obtained in a yield of 29% (vs. TrisAPB). It confirmed that it was a single compound by HPLC, and confirmed the structure by < ¹ > H-NMR.

¹ H-NMR (DMSO): δ = 5.23 (s, 4H), 6.14-6.95 (m, 9H), 6.98 (t, 2H), 7.10-7.29 (m , 3H), 7.38-7.73 (m, 6H), 7.93-8.10 (m, 3H)

(Synthesis Example 2)
Synthesis of Polyamic Acid In a container equipped with a stirrer and a nitrogen introduction tube, 5.92 g of TrisAPB-mPEPI obtained in Synthesis Example 1 was added, 16.6 g of DMAc was added as a solvent, and the mixture was stirred and dissolved at room temperature. The solution was charged with 3.03 g of BTDA and reacted at room temperature for 12 hours to synthesize polyamic acid. Subsequently, 8.22 g of DMAc was further added and stirred for a while to obtain a polyamic acid varnish having a polyamic acid solid content of 25% by weight. The obtained polyamic acid varnish had a logarithmic viscosity of 0.51 dl / g and an E-type viscosity at 25 ° C. of 1100 mPa · S.

Example 1
The polyamic acid varnish obtained in Synthesis Example 2 was cast on a glass plate, the uncrosslinked film (dry film) or the crosslinked film obtained by firing the cast film was subjected to the following test, and the uncrosslinked glass transition temperature ( Tg1), elastic modulus during plasticization (E′min), coefficient of linear expansion (CTE), post-crosslinking glass transition temperature (Tg2), and post-crosslinking elastic modulus (E ′ @ 300 ° C.) were measured. These results are shown in Table 1.

1) Uncrosslinked glass transition temperature (Tg1)
The cast film of polyamic acid varnish was baked at 240 ° C. for 30 minutes in a nitrogen atmosphere to produce an uncrosslinked polyimide film (dry film) (50 μm). This dry film was measured for elastic modulus up to 400 ° C. in a tensile mode at 1 Hz under a nitrogen atmosphere using RSA-III manufactured by TA Instruments Inc., and the loss elastic modulus (E ′ The temperature at which ') shows the peak top was defined as the uncrosslinked glass transition temperature (Tg1).

2) Elastic modulus during plasticization (E'min)
The elastic modulus of the dry film obtained in 1) was measured up to 400 ° C. in a tensile mode and 1 Hz in a nitrogen atmosphere using RSA-III manufactured by TA Instruments. And the minimum value of the storage elastic modulus measured in this range was made into the elastic modulus at the time of plasticization (E'min).

3) Linear expansion coefficient (CTE)
The cast film of the polyamic acid varnish was baked at 350 ° C. for 2 hours in a nitrogen atmosphere to produce a crosslinked film (thickness 50 μm). The crosslinked film was measured for a linear expansion coefficient in a range of 100 ° C. to 200 ° C. in a dry air atmosphere using a thermal analyzer TMA50 series manufactured by Shimadzu Corporation.

4) Glass transition temperature after crosslinking (Tg2)
The elastic modulus of the post-crosslinked film obtained in 3) was measured up to 400 ° C. in a tensile mode and 1 Hz in a nitrogen atmosphere using RSA-III manufactured by TA Instruments Inc. in this temperature range. The temperature at which the loss elastic modulus (E ″) showed the peak top was defined as the glass transition temperature (Tg2) after crosslinking.

5) Elastic modulus (E '@ 300 ° C)
In the solid viscoelasticity measurement measured in the same manner as described above, the storage elastic modulus at 350 ° C. was defined as the post-crosslinking elastic modulus (E ′ @ 300 ° C.).

  The thickness after drying the above polyamic acid varnish (precursor varnish of polyimide resin composition) on a commercially available polyimide film (trade name: Kapton 80EN, manufactured by Toray DuPont Co., Ltd.) with a gravure coater is 2. Coating was carried out to 5 μm. The coating film is dried at 70 ° C. for 5 minutes, at 100 ° C. for 2 minutes, at 140 ° C. for 2 minutes, at 180 ° C. for 2 minutes, and at 220 ° C. for 10 minutes, so that uncrosslinked thermoplastic polyimide is formed on both sides of the polyimide film. A polyimide insulating film (resin layer) having a layer was obtained.

  The polyimide insulating film and a commercially available copper foil (manufactured by Furukawa Circuit Foil Co., Ltd., trade name: F1-WS, thickness 18 μm) were thermocompression bonded under the following conditions using a hand press. The thermoplastic polyimide layer of the polyimide insulating film and the copper foil were bonded to each other, heated to 360 ° C. at a rate of 2 ° C./min while being pressure-bonded at 8 MPa, and held for 4 hours for adhesion. Thereby, a polyimide metal laminate (double-sided metal laminate) was obtained. The adhesion and dimensional accuracy of the obtained polyimide metal laminate were evaluated. These results are shown in Table 1.

6) Adhesiveness The said double-sided metal laminated plate sample (10 cm x 10 cm) was produced, and the cross section of this sample was observed with the transmission electron microscope. The adhesive surface of the copper foil is a rough surface, and when the polyimide layer is embedded in the rough surface without a gap, ○, and when the gap exists between the copper foil, the adhesiveness (adhesion) ).

7) Dimensional change rate The above-mentioned double-sided metal laminate sample (10 cm × 10 cm) was prepared, and after making holes in the four sides of this substrate, the copper foils on both sides were removed by etching. This double-sided metal laminate sample was left for 24 hours in an atmosphere of 50% humidity and 23 ° C. Thereafter, the rate of change in the distance between the formed holes was measured. The dimensional change was calculated from the average value of the copper foil conveyance direction and the direction perpendicular thereto. The calculation results are shown in Table 1.

(Comparative Example 1)
A container equipped with a PEPA-terminated polyamic acid stirrer and a nitrogen introduction tube was charged with 1375 g of DMAc as a solvent, and 351 g of APB was charged and stirred at room temperature until dissolved. Next, 381 g of BTDA and 8.94 g of PEPA were charged and stirred at room temperature for 12 hours to synthesize polyamic acid. Subsequently, 848 g of DMAc was further added and stirred for a while to obtain a polyamic acid varnish having a polyamic acid solid content of 25% by weight. The obtained polyamic acid varnish had a logarithmic viscosity of 0.64 dl / g and an E-type viscosity at 25 ° C. of 3000 mPa · S.

  The obtained polyamic acid varnish was cast on a glass plate and then fired, and an uncrosslinked film (dry film) or a crosslinked film was tested in the same manner as in Example 1. These results are shown in Table 1.

(Comparative Example 2)
With reference to the description in Patent Document 7, a conventional polyimide resin composition was prepared. In a vessel equipped with a stirrer and a nitrogen introduction tube, 793 g of DMAc was charged as a solvent, and then 205 g of APB was charged and stirred at room temperature for dissolution. To this solution, 222 g of BTDA was charged and stirred at room temperature for 12 hours to obtain a polyamic acid varnish. The logarithmic viscosity of the obtained polyamic acid varnish was 0.76 dl / g.

The obtained polyamic acid varnish and APB-BMI represented by the following formula were charged into a kneader bottle. At this time, it prepared so that APB-BMI might be 18 weight part with respect to 100 weight part of polyamic acid solid content in a polyamic acid varnish.

  The obtained solution was mixed and dissolved in a kneader, and DMAc was added so that the total solid concentration was 25 wt%, thereby preparing a light brown transparent polyamic acid varnish (precursor varnish of polyimide resin composition). Got. The obtained polyamide acid varnish had an E-type viscosity of 1160 mPa · S.

The obtained polyamic acid varnish was cast on a glass plate and then fired, and an uncrosslinked film (dry film) or a crosslinked film was tested in the same manner as in Example 1. These results are shown in Table 1.

If the polyimide resin of the present invention is used as an adhesive, adhesion at a low temperature can be realized, and deformation of the adhesive can be suppressed. Therefore, it is particularly preferably applied to the production of a metal laminate for a flexible electrical wiring plate.

Claims (14)

The following general formula have a structural unit represented by (1), the glass transition temperature of 240 ° C. or less 100 ° C. or higher, a polyimide resin.

[A ₁ in Formula (1) is

_{(R 1 to 4} may each have the same or different and a hydrogen atom, a halogen atom, selected from alkyl groups of 1 to 3 carbon atoms; _{R 5} is, -O -, - S -, - Selected from CH ₂ —, —C (CH ₃ ) ₂ —, —CO—; R ₆ is selected from a hydrogen atom and a phenyl group ;
B ₁ in the formula (1) is

(Y _1-6 may be the same or different and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) _2- , -SO _2- , or -NHCO-] The said structural unit is a polyimide resin of Claim 1 which is a structural unit represented by following General formula (2).

(A ₂ in Formula (2) is

Chosen from;
B ₁ in formula (2) is defined in the same manner as B ₁ in general formula (1)) The said structural unit is a polyimide resin of Claim 2 which is a structural unit represented by following General formula (3).

(A ₂ in formula (3) is defined in the same manner as A ₂ in general formula (2);
B ₂ in the formula (3) is

Selected from) The polyamic acid which has a structural unit represented by following General formula (4).

[A ₁ in Formula (4) is

_{(R 1 to 4} may each have the same or different and a hydrogen atom, a halogen atom, selected from alkyl groups of 1 to 3 carbon atoms; _{R 5} is, -O -, - S -, - Selected from CH ₂ —, —C (CH ₃ ) ₂ —, —CO—; R ₆ is selected from a hydrogen atom and a phenyl group ;
B ₁ in the formula (4) is

(Y _1-6 may be the same or different and are directly connected, —O—, —S—, —CO—, —COO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) _2- , -SO _2- , or -NHCO-] The said structural unit is a polyamic acid of Claim 4 which is a structural unit represented by following General formula (5).

(A ₂ in Formula (5) is

Chosen from;
B ₁ in formula (5) is defined in the same manner as B ₁ in general formula (4)) The said structural unit is a polyamic acid of Claim 5 which is a structural unit represented by following General formula (6).

(A ₂ in formula (6) is defined in the same manner as A ₂ in general formula (5);
B ₂ in the formula (6) is

Selected from) The dry film obtained from the polyimide resin as described in any one of Claims 1-3 . A metal laminate having a metal layer and a resin layer,
The said resin layer is a metal laminated body which has at least one layer containing the hardened | cured material of the polyimide resin as described in any one of Claims 1-3 . The resin layer of the said metal laminated body is a metal laminated body of Claim 8 which is a single layer containing the hardened | cured material of the polyimide resin as described in any one of Claims 1-3 . The metal laminate has a polyimide film, a polyimide layer formed on one or both sides of the polyimide film, and a metal layer laminated on the polyimide layer formed on the one or both sides,
The polyimide layer in contact with the metal layer, a layer containing a cured product of the polyimide resin according to any one of claims 1 to 3 metal laminate according to claim 8. The resin layer of the said metal laminated body has a layer containing the hardened | cured material of the polyimide resin as described in any one of Claims 1-3 with which the glass cloth was impregnated, In any one of Claims 8-10. The metal laminate according to the description. The adhesive sheet which has at least one contact bonding layer containing the polyimide resin as described in any one of Claims 1-3 . The adhesive sheet of Claim 12 which consists of a single layer containing the polyimide resin as described in any one of Claims 1-3 . The adhesive sheet according to claim 12 or 13 , comprising an adhesive layer containing the polyimide resin according to any one of claims 1 to 3 impregnated in a glass cloth.