JP5693422B2 - Heat-resistant double-sided metal laminate, heat-resistant transparent film using the same, and heat-resistant transparent circuit board - Google Patents

Description

  The present invention relates to a heat-resistant double-sided metal laminate, a heat-resistant transparent film using the same, and a heat-resistant transparent circuit board. Specifically, a heat-resistant double-sided metal laminate in which a metal foil is laminated on both sides of a polyimide layer containing a polyimide block containing a cyclohexanediamine unit and another polyimide block, a heat-resistant transparent film using the same, and a heat-resistant transparent circuit Regarding the substrate.

  Polyimide generally has superior heat resistance, mechanical properties, and electrical properties compared to other general-purpose resins and engineering plastics. Therefore, they are widely used in various applications as molding materials, composite materials, electric / electronic materials, optical materials, and the like. Particularly, a polyimide metal laminate having a metal foil and a polyimide layer used as a flexible printed board or the like needs to have reduced warpage.

  For example, as a polyimide having excellent film transparency and good thermal expansion coefficient (CTE) and tensile modulus, a block polyimide obtained by block copolymerization of cyclohexanediamine and another diamine is disclosed (patent) Reference 1).

  In recent years, the use of polyimide metal laminates capable of high-density mounting of components and elements as a circuit board material has been increasing as electronic devices have become smaller and more portable. And in order to respond | correspond to further densification, the polyimide metal laminated board suitable for the process of the fine pattern whose wiring width becomes 10-50 micrometers is desired. Furthermore, from the viewpoint of wiring reliability, it is necessary that the peel strength, which is an index of adhesion between metal and polyimide, is high. In the processing of fine patterns, the component and element mounting methods called TAB and COF (chip on film) are the mainstream, but at the time of mounting, a high temperature of about 300 to 500 ° C. called gold-gold bonding or gold-tin bonding. Joining is required. Furthermore, in consideration of the environment, it is required to mount components and elements with solder that does not contain lead. For this reason, the temperature at the time of mounting, especially the temperature at the time of removing parts and elements called repairs has become higher. Against this background, polyimide metal laminates are becoming increasingly important for fine processability and circuit reliability (peel strength and heat resistance at high temperatures). In addition, in order to improve the adhesion between the metal foil and the polyimide, the metal foil is roughened, but in this case, there is a problem that the etching residue of the metal is likely to occur and the wiring is easily short-circuited. is there.

  Therefore, a polyimide having low roughness metal foil and high adhesiveness is required. For example, as a polyimide suitable for laminating with a low-roughness metal foil, 1,3-bis (3-aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, 3,3′-di At least one diamine selected from the group consisting of amibenzophenone, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3′4,4′-benzophenonetetracarboxylic dianhydride, A polyimide comprising at least one tetracarboxylic dianhydride selected from the group consisting of pyromellitic dianhydride and 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride is disclosed (patent) Reference 2). When these are the main components, the peel strength of the polyimide metal laminate is very high and can be sufficiently used for conventional applications. However, when components or elements are mounted at a high temperature, problems such as deformation and peeling may occur. Therefore, it has been desired to develop a polyimide metal laminate suitable for use in mounting components and elements at higher temperatures.

International Publication No. 2010/113412 Pamphlet JP 2000-052483 A

  The object of the present invention is to have a metal foil on both sides of a polyimide film, have good adhesion to the metal foil, and have dimensions when mounted on a component or element at a high temperature or when the metal foil is etched. The object is to provide a heat-resistant double-sided metal laminate with little change.

  The present invention creates two laminates in which a metal foil, a block polyimide layer containing a cyclohexanediamine unit, and a thermoplastic polyimide layer are laminated in this order, and these laminates are made to face each other with the thermoplastic polyimide layers facing each other. And by heat-pressing at a predetermined temperature to make a heat-resistant double-sided metal laminate, it has excellent peel strength between the metal layer and the block polyimide layer, and further dimensional stability at high temperature and dimensional stability after etching It has been found out that it can be made into a heat-resistant double-sided metal laminate having excellent heat resistance.

（式（１Ａ）または式（１Ｂ）において、
ｍは、式（１Ａ）で表される繰返し構造単位の繰返し数を示し、
ｎは、式（１Ｂ）で表される繰返し構造単位の繰返し数を示し、
かつｍの平均値：ｎの平均値＝１：９〜９：１であり、
Ｒ^１およびＲ^３はそれぞれ独立して、炭素数４〜２７の４価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基であり、
Ｒ^２は、炭素数４〜５１の２価の基であり；かつ脂肪族基、単環式脂肪族基（但し、１，４−シクロへキシレン基を除く）、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基である）

（式（２）において、
Ｒ^４は、炭素数４〜５１の２価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基であり、
Ｒ^５はそれぞれ独立して、炭素数４〜２７の４価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基である） That is, the first of the present invention relates to the following heat-resistant double-sided metal laminate.
[1] A block polyamic acid imide comprising a metal foil, a block composed of a repeating structural unit represented by the following formula (1A), and a block composed of a repeating structural unit represented by the following formula (1B); A block polyamic acid imide solution containing a solvent is applied onto the metal foil, heat-dried to obtain a first layer, a glass transition temperature of 150 to 250 ° C., and represented by the following formula (2): A polyamic acid solution including a polyamic acid composed of repeating structural units and a solvent is applied on the first layer and heated to dry to prepare a second laminate having two layers, A heat-resistant double-sided metal laminate obtained by facing the second layers and thermocompression bonding at 250 to 300 ° C.

(In Formula (1A) or Formula (1B),
m represents the number of repeating structural units represented by the formula (1A),
n represents the number of repeating structural units represented by the formula (1B),
And average value of m: average value of n = 1: 9 to 9: 1,
R ¹ and R ³ are each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, or a monocyclic aromatic group Or a condensed polycyclic aromatic group, a cyclic aliphatic group is a non-condensed polycyclic aliphatic group linked directly or by a bridging member, or an aromatic group is directly or by a bridging member Non-fused polycyclic aromatic groups linked to each other;
R ² is a divalent group having 4 to 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group (excluding a 1,4-cyclohexylene group), a condensed polycyclic aliphatic group A monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group in which the cyclic aliphatic groups are connected to each other directly or by a bridging member, or aromatic A non-condensed polycyclic aromatic group in which the groups are connected to each other directly or by a bridging member)

(In Formula (2),
R ⁴ is a divalent group having ^{4 to} 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed polycyclic aromatic group. A non-condensed polycyclic aliphatic group in which the cyclic aliphatic group is directly or linked to each other by a bridging member, or a non-condensed group in which aromatic groups are linked to each other directly or by a bridging member A polycyclic aromatic group,
R ⁵ is each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed poly group. A cyclic aromatic group, a non-condensed polycyclic aliphatic group in which the cycloaliphatic groups are directly or mutually linked by a bridging member, or an aromatic group that is linked directly or by a bridging member Non-condensed polycyclic aromatic group)

[2] The heat-resistant double-sided metal laminate according to [1], wherein an oxygen concentration in an environmental atmosphere during heating and drying of the coating film of the block polyamic acid imide solution is 1% or less.
[3] The average rate of temperature increase in the temperature range of 150 to 300 ° C. during heating and drying of the coating film of the block polyamic acid imide solution is 0.25 to 50 ° C./min. [1] Or the heat-resistant double-sided metal laminated plate as described in [2].

[4] The heat-resistant double-sided metal laminate according to any one of [1] to [3], wherein the metal foil is a copper foil having a surface 10-point average roughness (Rz) of 3 μm or less.
[5] The peel strength between the metal foil and the first layer is 0.5 kN / m or more, and there is no change in shape after bathing in 260 ° C. solder for 10 seconds. The heat-resistant double-sided metal laminate according to any one of [1] to [4], wherein a dimensional change rate is 0.2% or less and a total light transmittance after etching of the metal foil is 80% or more. .

（式（３Ａ）または式（３Ｂ）において、
ｍは、式（３Ａ）で表される繰返し構造単位の繰返し数を示し、
ｎは、式（３Ｂ）で表される繰返し構造単位の繰返し数を示し、
かつｍの平均値：ｎの平均値＝１：９〜９：１であり、
Ｒ^６およびＲ^８はそれぞれ独立して、炭素数４〜２７の４価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基であり、
Ｒ^７は、炭素数４〜５１の２価の基であり；かつ脂肪族基、単環式脂肪族基（但し、１，４−シクロへキシレン基を除く）、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基である）

（式（４）において、
Ｒ^９は、炭素数４〜５１の２価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基であり、
Ｒ^１０はそれぞれ独立して、炭素数４〜２７の４価の基であり；かつ脂肪族基、単環式脂肪族基、縮合多環式脂肪族基、単環式芳香族基もしくは縮合多環式芳香族基であるか、環式脂肪族基が直接もしくは架橋員により相互に連結された非縮合多環式脂肪族基であるか、または芳香族基が直接もしくは架橋員により相互に連結された非縮合多環式芳香族基である） [6] A heat-resistant double-sided metal laminate in which a first metal foil, a first block polyimide layer, a thermoplastic polyimide layer, a second block polyimide layer, and a second metal foil are laminated in this order, A block in which the first block polyimide layer and the second block polyimide layer are composed of a repeating structural unit represented by the following formula (3A) and a repeating structural unit represented by the following formula (3B) The thermoplastic polyimide layer is made of a polyimide having a glass transition temperature of 150 to 250 ° C. and a repeating structural unit represented by the following formula (4), and the metal foil is A copper foil having a surface 10-point average roughness (Rz) of 3 μm or less, peel strength between the first metal foil and the first block polyimide layer, and the second metal foil and the front Peel strength between the second block polyimide layer is both 0.5 kN / m or more, the heat sided metal laminate.

(In Formula (3A) or Formula (3B),
m represents the number of repeating structural units represented by the formula (3A),
n represents the number of repeating structural units represented by the formula (3B),
And average value of m: average value of n = 1: 9 to 9: 1,
R ⁶ and R ⁸ are each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, or a monocyclic aromatic group Or a condensed polycyclic aromatic group, a cyclic aliphatic group is a non-condensed polycyclic aliphatic group linked directly or by a bridging member, or an aromatic group is directly or by a bridging member Non-fused polycyclic aromatic groups linked to each other;
R ⁷ is a divalent group having 4 to 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group (excluding a 1,4-cyclohexylene group), a condensed polycyclic aliphatic group A monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group in which the cyclic aliphatic groups are connected to each other directly or by a bridging member, or aromatic A non-condensed polycyclic aromatic group in which the groups are connected to each other directly or by a bridging member)

(In Formula (4),
R ⁹ is a divalent group having 4 to 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed polycyclic aromatic group. A non-condensed polycyclic aliphatic group in which the cyclic aliphatic group is directly or linked to each other by a bridging member, or a non-condensed group in which aromatic groups are linked to each other directly or by a bridging member A polycyclic aromatic group,
R ¹⁰ is each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed poly group. A cyclic aromatic group, a non-condensed polycyclic aliphatic group in which the cycloaliphatic groups are directly or mutually linked by a bridging member, or an aromatic group that is linked directly or by a bridging member Non-condensed polycyclic aromatic group)

The second of the present invention relates to the heat-resistant transparent film or heat-resistant transparent circuit board shown below.
[7] A heat-resistant transparent film obtained by etching the heat-resistant double-sided metal laminate according to any one of [1] to [6].
[8] A heat-resistant transparent circuit board obtained by etching the heat-resistant double-sided metal laminate according to any one of [1] to [6].

  In the present invention, two laminates in which a block polyimide layer containing a cyclohexanediamine unit and a thermoplastic polyimide layer are laminated in this order are prepared, and these laminates are made to face each other with a predetermined thickness of the thermoplastic polyimide layers. A heat-resistant double-sided metal laminate is obtained by thermocompression bonding at a temperature. Therefore, the adhesion between the block polyimide layer and the metal foil can be made high. In addition, since it contains a block polyimide layer containing cyclohexanediamine units, the light transmittance of the polyimide film after removing the metal foil is high, and high dimensional stability is also obtained after etching and when mounting elements at high temperatures. It can be set as a heat-resistant double-sided metal laminate.

It is sectional drawing which shows an example of the structure of the heat-resistant double-sided metal laminated plate of this invention.

  The heat-resistant double-sided metal laminate of the present invention is produced by a specific method. That is, a metal foil, a first layer obtained by applying and drying a block polyamic acid imide solution containing a specific block polyamic acid imide, and a first layer obtained by applying and drying a polyamic acid solution containing a specific polyamic acid. Two layers are prepared in which two layers are laminated in this order, these second layers are opposed to each other, and are heat-pressed at a predetermined temperature.

(First layer)
The first layer is obtained by applying a block polyamic acid imide solution containing a block polyamic acid imide and a solvent on a metal foil, followed by heating and drying.
The method for applying the block polyamic acid imide solution on the metal foil is appropriately selected according to the viscosity of the block polyamic acid imide solution, for example, die coater, comma coater, roll coater, gravure coater, curtain coater, spray coater, etc. These known methods can be employed.

  As a method for heat-drying the coating film of the block polyamic acid imide solution, a normal heat-drying furnace can be used. As the atmosphere of the drying furnace, air, inert gas (nitrogen, argon), or the like can be used, but the oxygen concentration in the environmental atmosphere is preferably 1% or less, more preferably 0.8% or less, and 0.5% or less. Is more preferable. When the oxygen concentration in the environmental atmosphere is high, the total light transmittance may be reduced due to coloring of the obtained first layer.

  Moreover, although the heat drying of the coating film of a block polyamic acid imide solution may be performed at a fixed temperature, it is preferable to perform the heat drying while gradually raising the temperature of the coating film. When the temperature of the coating film of the block polyamic acid imide solution is suddenly increased, foaming or whitening associated with the imidization reaction may occur on the surface, or the dimensional stability of the resulting heat-resistant double-sided metal laminate may be reduced.

  In this invention, it is preferable to make the average temperature increase rate at the time of coating-film drying into 0.25-50 degreeC / min in the temperature range of 150 degreeC-300 degreeC, 1-25 degreeC / min is more preferable, 2 10 ° C./min is more preferable. The heating rate in the above temperature range may be constant or may be changed in two or more steps. When changing to two steps or more, it is preferable to set each temperature increase rate to 0.25 ° C./min or more and 50 ° C./min or less. However, as long as the average value of the heating rate is within the above range, it may be temporarily outside this range. Furthermore, although the temperature rise may be continuous or stepwise (sequential), it is preferable to make it continuous from the viewpoint of controlling the appearance of the first layer and whitening associated with the imidization reaction. In addition, it is not necessary to heat a coating film to 300 degreeC. When the temperature rise end temperature is less than 300 ° C., the average temperature rise rate in the range from 150 ° C. to the temperature rise end temperature is preferably 0.25 to 50 ° C./min.

  The temperature rise end temperature is usually preferably 230 to 300 ° C, more preferably 250 to 270 ° C. If the temperature rise end temperature of the coating film is too high, the metal foil may be oxidized and deteriorated. On the other hand, if the temperature rise end temperature is too low, it takes time to dry the coating film, which is not preferable from the standpoint of production efficiency.

  After heating at the above average heating rate, the coating film may be further heated and dried at a constant temperature to imidize the polyamic acid in the block polyamic acid imide.

  The thickness of the first layer is appropriately selected depending on the use of the heat-resistant double-sided metal laminate, and the thickness after drying is preferably 1 to 100 μm, more preferably 10 to 40 μm.

  The first layer preferably has a low coefficient of thermal expansion (CTE) in the range of 100 to 200 ° C. For example, when a copper foil is used as the metal foil, it is preferably 20 ppm / K or less, more preferably 17 ppm / K or less. When the thermal expansion coefficient of the first layer is high, the heat-resistant double-sided metal laminate may be warped at a high temperature or the dimensional stability may be reduced. The thermal expansion coefficient of the first layer can be lowered by increasing the amount of cyclohexanediamine unit in the block polyamic acid imide.

  The glass transition temperature (Tg) of the first layer is preferably 260 to 350 ° C. When the Tg of the first layer is low, the heat resistance of the heat-resistant double-sided metal laminate may be insufficient. The glass transition temperature of the first layer can be adjusted by the amount of cyclohexanediamine unit in the block polyamic acid imide.

-Block polyamic acid imide acid solution The said block polyamic acid imide solution used for formation of the above-mentioned 1st layer contains block polyamic acid imide and a solvent.
(I) Block polyamic acid imide The block polyamic acid imide includes a block composed of a repeating structural unit represented by the following formula (1A) and a block composed of a repeating structural unit represented by the following formula (1B): Have

  M and n in Formula (1A) and Formula (1B) represent the number of repeating structural units in each block. The average value of m and the average value of n are each independently preferably 2 to 1000, and more preferably 5 to 500. The average value of m is obtained by dividing the total number of repeating structural units represented by the formula (1A) contained in the block polyamic acid imide by the total number of blocks composed of the repeating structural units represented by the formula (1A). Value. The average value of n is the total number of repeating structural units represented by the formula (1B) contained in the block polyamic acid imide divided by the total number of blocks composed of the repeating structural units represented by the formula (1B). Value.

  Further, the ratio of m to n is preferably an average value of m: an average value of n = 9: 1 to 1: 9, and an average value of m: an average value of n = 8: 2 to 2: 8. More preferably. When the ratio of the repeating number m of the repeating structural unit represented by the formula (1A) is a certain value or more, the thermal expansion coefficient of the block polyimide obtained by dehydrating condensation of the block polyamic acid imide becomes small. Moreover, the visible light transmittance | permeability of block polyimide will also become it that the ratio of the repetition number m is more than fixed. On the other hand, since cyclohexanediamine is generally expensive, reducing the ratio of the number m of repeating structural units represented by the formula (1A) can reduce the cost.

  The ratio of the total number of repeating structural units represented by the formula (1A) and the total number of repeating structural units represented by the formula (1B) contained in the block polyamic acid imide is also (1A) :( 1B) = 9 : 1 to 1: 9 is preferable, and (1A) :( 1B) = 8: 2 to 2: 8 is more preferable.

  Furthermore, in all the blocks represented by the formula (1A) contained in the block polyamic acid imide of the present invention, the number of repeating structural units represented by the formula (1A) is preferably 2 or more, It is more preferably 5 or more, and further preferably 10 or more. Moreover, from the viewpoint of the compatibility between the polyamic acid oligomer and the polyimide oligomer during the production of the block polyamic acid imide, the number of repeating structural units represented by the formula (1A) is preferably 50 or less. When all of the blocks represented by the formula (1A) included in the block polyimide include a certain number or more of repeating structural units, it is easy to obtain characteristics derived from the block. That is, since all the blocks represented by the formula (1A) contain a certain number or more of the repeating structural units, cyclohexane is included in comparison with the case where the repeating structural units represented by the above formula (1A) are randomly included. It is easy to develop characteristics derived from diamine, particularly low thermal expansion coefficient.

Further, the cyclohexane skeleton in the formula (1A) has a trans isomer represented by the formula (1A-1) and a cis isomer represented by the formula (1A-2).

  The ratio of the trans isomer of the cyclohexane skeleton in the formula (1A) to the cis isomer is preferably trans isomer: cis isomer = 10: 0 to 5: 5, and trans isomer: cis isomer = 10: 0 to 7: 3. It is more preferable that

R ¹ in the formula (1A) represents a tetravalent group. R ¹ preferably has 4 to 27 carbon atoms. Furthermore, R ¹ is an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group or a condensed polycyclic aromatic group; the cyclic aliphatic group is directly or It is preferably a non-condensed polycyclic aliphatic group interconnected by a cross-linking member; or an aromatic group is a non-condensed polycyclic aromatic group interconnected directly or by a cross-linking member.

R ¹ in the formula (1A) is a group derived from tetracarboxylic dianhydride, and the tetracarboxylic dianhydride is, for example, an aromatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride. It can be.

  Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetra Carboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, bis (3,4-dicarboxyphenyl) 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-dicarboxy) Phenoxy) benzene dianhydride, 4,4'-bis (3,4-dicarboxyphe) Xyl) biphenyl dianhydride, 2,2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5 , 8-Naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenonetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2 -Bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, Bis (2,3-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) sulfide dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, 1,3-bis (2,3-Dicarboxyphenoxy) benzene dianhydride, 1,4-bis (2,3- Carboxyphenoxy) benzene dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,3-bis (3,4-dicarboxybenzoyl) benzene dianhydride, 1,4-bis (3 , 4-dicarboxybenzoyl) benzene dianhydride, 1,3-bis (2,3-dicarboxybenzoyl) benzene dianhydride, 1,4-bis (2,3-dicarboxybenzoyl) benzene dianhydride, 4,4'-isophthaloyldiphthalic anhydride diazodiphenylmethane-3,3 ', 4,4'-tetracarboxylic dianhydride, diazodiphenylmethane-2,2', 3,3'-tetracarboxylic dianhydride 2,3,6,7-thioxanthone tetracarboxylic dianhydride, 2,3,6,7-anthraquinone tetracarboxylic dianhydride, 2,3,6,7-xanthone tetracarboxylic dianhydride, Ethylenetetracarboxylic acid Anhydride, and the like.

  Examples of alicyclic tetracarboxylic dianhydrides include cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5, 6-tetracarboxylic dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, bicyclo [ 2.2.1] Heptane-2,3,5-tricarboxylic acid-6-acetic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6- Tetracarboxylic dianhydride, decahydro-1,4,5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic dianhydride, 4- (2,5-dioxoteto Hydrofuran-3-yl) - tetralin-1,2-dicarboxylic acid dianhydride, 3,3 ', etc. 4,4'-dicyclohexylmethane tetracarboxylic dianhydride.

  When the tetracarboxylic dianhydride includes an aromatic ring such as a benzene ring, some or all of the hydrogen atoms on the aromatic ring are fluoro group, methyl group, methoxy group, trifluoromethyl group, and trifluoromethoxy group. It may be substituted with a group selected from groups and the like. Further, when the tetracarboxylic dianhydride contains an aromatic ring such as a benzene ring, the ethynyl group, benzocyclobuten-4′-yl group, vinyl group, allyl group, cyano group, isocyanate group depending on the purpose. , A nitrilo group, an isopropenyl group, and the like may be present as a crosslinking point. In the tetracarboxylic dianhydride, a group that becomes a crosslinking point such as vinylene group, vinylidene group, and ethynylidene group may be incorporated in the main chain skeleton, preferably within a range that does not impair molding processability. .

  In addition, a part of tetracarboxylic dianhydride may be hexacarboxylic dianhydrides or octacarboxylic dianhydrides. This is for introducing branching into the polyamide or polyimide.

  These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

R ² in the formula (1B) represents a divalent group other than the 1,4-cyclohexylene group. R ² preferably has 4 to 51 carbon atoms. Further, R ² represents an aliphatic group, a monocyclic aliphatic group (excluding a 1,4-cyclohexylene group), a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed polycyclic aromatic group. A non-condensed polycyclic aliphatic group in which the cycloaliphatic groups are directly or linked to each other by a bridging member; or a non-fused group in which the aromatic groups are linked to each other directly or by a bridging member A polycyclic aromatic group is preferred.

R ² in the formula (1B) is a group derived from a diamine, and the diamine is not particularly limited as long as a polyamic acid or a polyimide can be produced.

A first example of a diamine is a diamine having a benzene ring. Examples of diamines having a benzene ring include
<1> Diamine having one benzene ring such as p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine;
<2> 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4′- Diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,4 '-Diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4- Aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2,2-di (3-aminophenyl)- , 1,1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2- (3-aminophenyl) ) -2- (4-Aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-di (3-aminophenyl) -1-phenylethane, 1,1-di ( Diamines having two benzene rings such as 4-aminophenyl) -1-phenylethane, 1- (3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane;
<3> 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4- Aminophenoxy) benzene, 1,3-bis (3-aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, 1,4-bis (3-aminobenzoyl) benzene, 1,4-bis ( 4-Aminobenzoyl) benzene, 1,3-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-Amino-α, α-dimethylbenzyl) benzene, 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (3-amino-α, α-ditrifluoromethyl) Benzyl) benzene, 1,3-bis (4-amino-α, α-ditrifluoromethylben) L) benzene, 1,4-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 2,6- A diamine having three benzene rings such as bis (3-aminophenoxy) benzonitrile, 2,6-bis (3-aminophenoxy) pyridine;
<4> 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- ( 4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone Bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 2,2-bis [4 -(3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophene) Noxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3- A diamine having four benzene rings such as hexafluoropropane;
<5> 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3- Aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, , 3-Bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4 A diamine having five benzene rings such as bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene;
<6> 4,4′-bis [4- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4 Has 6 benzene rings such as' -bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, 4,4'-bis [4- (4-aminophenoxy) phenoxy] diphenylsulfone Diamine is included.

  A second example of a diamine is 3,3′-diamino-4,4′-diphenoxybenzophenone, 3,3′-diamino-4,4′-dibiphenoxybenzophenone, 3,3′-diamino-4- Diamines having aromatic substituents such as phenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone are included.

  A third example of a diamine includes 6,6′-bis (3-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4 -Aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane and other diamines having a spirobiindane ring are included.

  A fourth example of a diamine includes 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-aminobutyl) tetramethyldisiloxane, α, ω-bis (3-amino Siloxane diamines such as propyl) polydimethylsiloxane and α, ω-bis (3-aminobutyl) polydimethylsiloxane are included.

  Examples of diamines include bis (aminomethyl) ether, bis (2-aminoethyl) ether, bis (3-aminopropyl) ether, bis (2-aminomethoxy) ethyl] ether, bis [2- ( 2-aminoethoxy) ethyl] ether, bis [2- (3-aminoprotoxy) ethyl] ether, 1,2-bis (aminomethoxy) ethane, 1,2-bis (2-aminoethoxy) ethane, 1, 2-bis [2- (aminomethoxy) ethoxy] ethane, 1,2-bis [2- (2-aminoethoxy) ethoxy] ethane, ethylene glycol bis (3-aminopropyl) ether, diethylene glycol bis (3-aminopropyl) And ethylene glycol diamines such as ether and triethylene glycol bis (3-aminopropyl) ether.

  Sixth examples of diamines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8- Alkylene diamines such as diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane are included.

  Seventh examples of diamines include cyclobutanediamine, di (aminomethyl) cyclohexane [trans-1,4-bis (aminomethyl) cyclohexane, bis (aminomethyl) including 1,3-bis (aminomethyl) cyclohexane, etc. Cyclohexane], diaminobicycloheptane, diaminomethylbicycloheptane (including norbornanediamines such as norbornanediamine), diaminooxybicycloheptane, diaminomethyloxybicycloheptane (including oxanorbornanediamine), isophoronediamine, diaminotricyclodecane, diamino Alicyclic diamines such as methyltricyclodecane, bis (aminocyclohexyl) methane [or methylenebis (cyclohexylamine)], bis (aminocyclohexyl) isopropylidene Etc. are included.

R ³ in Formula (1B) is a tetravalent group and is a group derived from tetracarboxylic dianhydride. Examples of R ³ include the same groups as R ¹ in formula (1A).

(Ii) Manufacturing method of block polyamic acid imide Block polyamic acid imide is represented by the polyamic acid (polyamic acid oligomer) comprised by the repeating structural unit represented by said Formula (1A), and said Formula (1B). It can be obtained by reacting with a polyimide (polyimide oligomer) composed of repeating structural units. The reaction is preferably performed in a solvent, and more preferably performed in an aprotic polar solvent. The polyamic acid oligomer composed of the repeating structural unit represented by (1A) can usually be dissolved in an aprotic polar solvent. Then, if the polyimide comprised by the repeating structural unit represented by Formula (1B) can be melt | dissolved in an aprotic polar solvent, these can be mixed uniformly and a block polyamic-acid imide can be obtained easily.

  Examples of aprotic polar solvents include aprotic amide solvents; examples of aprotic amide solvents include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, hexamethylphosphorotriamide and the like; among these amide solvents, N, N-dimethyl is preferable. Formamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone. The dissolution means that the dissolution amount is 10 g / l or more, preferably 100 g / l or more.

In the reaction of the polyamic acid (polyamic acid oligomer) and the polyimide (polyimide oligomer), the terminal of the polyamic acid oligomer represented by the formula (1A) is used as the acid anhydride terminal; the formula (1B) When the terminal of the polyimide oligomer to be used is an amine terminal, gelation tends to occur in the heating imidization reaction. The cause of gelation is not clear, but it is presumed that an excessive amine moiety or an acid anhydride structure forms an excessive bond other than an imide bond and a crosslinked structure is formed. Therefore, an amine-terminated polyamic acid oligomer represented by the following formula (1A ′) and an acid anhydride-terminated polyimide oligomer represented by the following formula (1B ′) are reacted to form a polyamic acid imide. preferable.

R ¹ in formula (1A ′) is a tetravalent group defined in the same manner as R ¹ in formula (1A). R ² and R ³ in formula (1B ′) are a divalent group or a tetravalent group defined in the same manner as R ² and R ³ in formula (1B), respectively.

The polyamic acid oligomer represented by the above formula (1A ′) is a dehydration polycondensation of 1,4-cyclohexanediamine represented by the following formula (5) and a tetracarboxylic dianhydride represented by the following formula (6). Obtained by reaction. Here, the ratio of the number of moles of tetracarboxylic dianhydride of formula (6) to the number of moles of diamine of formula (5) to be subjected to dehydration polycondensation reaction (tetracarboxylic dianhydride of formula (6) / formula ( The diamine 5) is preferably 0.5 or more and less than 1.0, more preferably 0.7 or more and less than 1. This is to obtain an amine-terminated polyamic acid oligomer whose molecular weight is appropriately controlled.

R ¹ in formula (6) is a tetravalent group defined in the same manner as R ¹ in formula (1A).

The polyimide oligomer represented by the above formula (1B ′) is obtained by a dehydration condensation reaction and an imidization reaction between a diamine represented by the following formula (7) and a tetracarboxylic dianhydride represented by the following formula (8). It is done. Here, the ratio of the number of moles of the diamine of the formula (7) to the number of moles of the tetracarboxylic dianhydride of the formula (8) to be subjected to the dehydration condensation reaction (the diamine of the formula (7) / the tetracarboxylic acid bis of the formula (8) (Anhydride) is preferably 0.5 or more and less than 1.0, more preferably 0.7 or more and less than 1. This is to obtain an acid anhydride-terminated polyimide oligomer whose molecular weight is appropriately controlled.

R ² and R ³ in the formulas (7) and (8) are respectively a divalent group or a tetravalent group defined in the same manner as R ² and R ³ in the formula (1B).

  The dehydration condensation reaction between diamine and tetracarboxylic dianhydride is preferably carried out in a reaction solvent; the reaction solvent can be an aprotic polar solvent or a water-soluble alcohol solvent, but preferably aprotic Polar solvent. Examples of aprotic polar solvents include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, etc .; 2-methoxyethanol which is an ether compound, 2-ethoxyethanol, 2- (methoxymethoxy) ethoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol Ethylene glycol monoethyl ether, tetraethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropyleneglycol And dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, polypropylene glycol, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and the like. Examples of water-soluble alcohol solvents include methanol, ethanol, 1-propanol, 2-propanol, tert-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,3-butanediol. 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 1,2,6-hexane Triol, diacetone alcohol and the like are included.

  As the solvent for the dehydration condensation reaction, these solvents can be used alone or in admixture of two or more. Among these, preferred examples of the solvent include N, N-dimethylacetamide, N-methylpyrrolidone or a combination thereof.

  A polyamic acid oligomer composed of the formula (1A) (preferably represented by the formula (1A ′)) and a polyimide oligomer composed of the formula (1B) (preferably represented by the formula (1B ′)), Mix in an aprotic polar solvent to obtain a block polyamic acid imide. The aprotic polar solvent is not particularly limited as long as it dissolves the polyimide oligomer constituted by the formula (1B), and examples thereof include solvents used for the dehydration condensation reaction between the above-mentioned diamine and tetracarboxylic dianhydride. For example, N-methyl-2-pyrrolidone. The mixing method includes, for example, mixing with a three-one motor, a homomixer, a planetary mixer, a homogenizer, a high-viscosity material stirring and defoaming mixer, and the kneading may be performed while heating in the range of 10 to 150 ° C.

(Iii) Solvent The solvent used for the block polyamic acid imide solution may be a solvent used when producing the above polyamic acid imide, that is, an aprotic polar solvent.
The solid content concentration of the block polyamic acid imide solution is appropriately selected according to the viscosity and the like. The solid content concentration of the block polyamic acid imide solution is preferably 5 to 70% by weight, more preferably 10 to 40% by weight.

  The viscosity of the block polyamic acid imide solution is preferably 0.1 to 100 Pa · s, more preferably 0.5 to 50 Pa · s in consideration of applicability to the metal foil. The viscosity is a viscosity measured by an E-type viscosity at 25 ° C., and can be adjusted by the amount of the solvent.

Metal foil The metal type of the metal foil used in the present invention is not particularly limited, but examples include copper and copper alloys, stainless steel and alloys thereof, nickel and nickel alloys (including 42 alloys), aluminum and aluminum alloys, and the like. It is done. Copper and copper alloy are preferable. In addition, those obtained by forming a rust preventive layer or a heat-resistant layer (for example, plating treatment of chromium, zinc, etc.) on these metal surfaces, or those subjected to a silane coupling agent treatment can be used. Preferably, copper and / or nickel, zinc, iron, chromium, cobalt, molybdenum, tungsten, vanadium, beryllium, titanium, tin, manganese, aluminum, phosphorus, silicon, etc. and at least one component and copper are included. It is a copper alloy. A particularly desirable metal foil is a copper foil formed by rolling or electrolytic plating, and its preferred thickness is 3 to 150 μm, more preferably 3 to 35 μm, and more preferably 3 to 12 μm.

  Even if the metal foil is not subjected to any roughening treatment on both sides, it may be subjected to roughening treatment on one side or both sides, but preferably a low-roughness or non-roughening treatment foil is preferred. As examples of commercially available products, F1-WS, F0-WS (trade name, manufactured by Furukawa Electric Co., Ltd.), BHY, NK120 (trade name, manufactured by JX Nippon Mining & Metals), SLP, USLP (Japan) ELECTRIC CO., LTD. Trade name), TQ-VLP, SQ-VLP, FQ-VLP, NA-DFF (Mitsui Metal Mining Co., trade name), C7025, B52 (Olin trade name) and the like.

  The 10-point average roughness (Rz) of the surface of the metal foil in contact with the polyimide layer is preferably less than 3 μm, more preferably 2 μm or less, still more preferably 1 μm or less, and the back surface is 3 μm or less, preferably Is 2 μm or less, more preferably 1 μm or less.

  The 10-point average roughness (Rz) of the surface is a method specified in JIS B-0601. The cut-off value is 0.25 mm, the measurement length is 2.5 mm, and the measurement is performed in the width direction of the metal foil. Is the method.

Furthermore the surface of the surface in contact with the polyimide layer of the metal foil, nickel 0.05~1.0mg / dm ^2, preferably 0.1~0.4mg / dm ^2, zinc 0.5 mg / dm ² or less, preferably Is 0 mg / dm ² or more and 0.3 mg / dm ² or less, more preferably 0 mg / dm ² or more and 0.2 mg / dm ² or less, chromium is 0.2 mg / dm ² or less, preferably 0 mg / dm ² or more and 0.1 mg / dm ^2. It is desirable in terms of circuit reliability that dm ² or less and silicon are 0.2 mg / dm ² or less, preferably 0 mg / dm ² or more and 0.1 mg / dm ² or less. Moreover, it is preferable that the surface not contacting the polyimide layer is also subjected to nickel or zinc plating and further chromate treatment.

  Here, silicon is derived from a silane coupling agent applied for the purpose of enhancing adhesion with polyimide. This silane coupling agent is generally formed by uniformly applying a solution dissolved in alcohol or water on the outermost layer of the metal foil surface treatment, and then drying and forming at about 50 to 150 ° C. Representative examples include vinylsilanes such as vinyltrimethoxysilane, epoxysilanes such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and aminosilanes such as γ-aminopropyltrimethoxysilane. It is not limited.

(Second layer)
The second layer can be produced by applying a polyamic acid solution containing a specific polyamic acid and a solvent on the first layer, and drying by heating.
The method for applying the polyamic acid solution on the first layer is appropriately selected according to the viscosity of the polyamic acid solution and the like, and a known method similar to that used for forming the first layer can be employed.

  Moreover, as a heating drying method of the applied polyamic acid solution, a normal heating drying furnace can be used. As the atmosphere of the drying furnace, air, inert gas (nitrogen, argon) or the like can be used. Also during the heat drying of the second layer, the oxygen concentration is preferably 1% or less, more preferably 0.8% or less, and even more preferably 0.5% or less. When the oxygen concentration is high, the total light transmittance may decrease, for example, the obtained second layer may be colored.

  Further, the heat drying of the coating film of the polyamic acid solution may be performed at a constant temperature, may be raised in stages (sequentially), or may be continuously raised. Polyamic acid may be imidized by the heat drying.

  The thickness of the second layer is appropriately selected according to the application of the heat-resistant double-sided metal laminate, and the film thickness after drying is preferably 0.1 to 10 μm, more preferably 1 to 5 μm.

  The glass transition temperature of the second layer is 150 to 250 ° C, preferably 180 to 230 ° C, more preferably 200 to 225 ° C. When the glass transition temperature is high, as will be described later, two laminates having a metal foil, a first layer, and a second layer in this order are produced, and these second layers are opposed to each other when thermocompression bonded. It is necessary to increase the temperature. Moreover, when the glass transition temperature is too low, the heat resistance of the heat-resistant double-sided metal laminate may be insufficient.

-Polyamic acid solution The said polyamic acid solution used for formation of the above-mentioned 2nd layer contains a polyamic acid and a solvent.

(I) Polyamic acid The polyamic acid contained in the polyamic acid solution is composed of a repeating structural unit represented by the following formula (2).

R ⁴ in the formula (2) is a group derived from a diamine, and the diamine is not particularly limited as long as a polyamic acid or a polyimide can be produced.

  Examples of the diamine include a diamine having a benzene ring, a diamine having an aromatic substituent, a diamine having a spirobiindane ring, a siloxane diamine, an ethylene glycol diamine, an alkylene diamine, and an alicyclic diamine. These diamines may be the same as the diamines in formula (1B) of the first layer. However, among these, alicyclic diamines are preferable because of their excellent transparency.

R ⁵ in Formula (2) is a tetravalent group and is a group derived from tetracarboxylic dianhydride. Examples of R ⁵ include the same group as R ¹ in the formula (1A) of the first layer.

(Ii) Solvent The solvent to be blended in the polyamic acid solution is not particularly limited as long as it can dissolve the polyamic acid. For example, it can be the same as the aprotic polar solvent blended in the block polyamic acid imide solution described above. .

  The addition amount of the solvent is appropriately selected according to the viscosity of the polyamic acid solution. The solid content concentration of the polyamic acid solution is preferably 5 to 30% by weight, and more preferably 5 to 15% by weight.

  In addition, the viscosity of the polyamic acid solution is preferably 0.05 to 5 Pa · s, more preferably 0.1 to 1 Pa · s in consideration of applicability to the first layer. The viscosity is a viscosity measured by an E-type viscosity at 25 ° C., and can be adjusted by the amount of the solvent.

(Thermo-compression bonding of the laminate)
In the present invention, two laminates in which the metal foil, the first layer, and the second layer obtained as described above are laminated are prepared. The two laminates are thermocompression bonded at 250 to 300 ° C. with the second layers facing each other. The thermocompression bonding can be performed by, for example, a known press machine.

  The temperature at the time of thermocompression bonding is more preferably 250 to 300 ° C, and further preferably 250 to 270 ° C. If the temperature during thermocompression bonding is low, the peel strength between the metal foil and the first layer may not be sufficient. On the other hand, if the temperature at the time of thermocompression bonding is high, the total light transmittance of the first layer or the second layer may be lowered, and further foaming may occur in the first layer or the second layer.

  The pressure during thermocompression bonding is preferably 1 to 20 MPa, more preferably 1 to 10 MPa. By setting the pressure within the above range, it is possible to sufficiently bond the second layers of the two laminates.

  The thermocompression bonding time is not particularly limited, and can be usually 10 minutes to 10 hours, preferably 1 to 3 hours. By performing thermocompression bonding for the above time, the second layers can be sufficiently bonded together.

(About heat-resistant double-sided metal laminates)
The body heat double-sided metal laminate of the present invention obtained by the above-described method includes, for example, as shown in FIG. 1, a first metal foil 1, a first block polyimide layer 2, a thermoplastic polyimide layer 3, and a second block polyimide layer 2. “And the second metal foil 1” are laminated. In addition, 1st metal foil 1 and 2nd metal foil 1 'consist of the above-mentioned metal foil, respectively, and 1st metal foil 1 and 2nd metal foil 1' may differ.

上記式（３Ａ）におけるＲ^６は、前記式（１Ａ）におけるＲ^１と同様の４価の基である。また上記式（３Ｂ）におけるＲ^７及びＲ^８は、それぞれ前記式（１Ｂ）におけるＲ^２及びＲ^３と同様の２価の基または４価の基である。また、ｍ及びｎについても前記式（１Ａ）及び（１Ｂ）で特定する値と同様である。
なお、第１ブロックポリイミド層２と第２ブロックポリイミド層２’とは異なっていてもよい。 The first block polyimide layer 2 and the second block polyimide layer 2 ′ are layers in which the amic acid in the block polyamic acid imide used for the production of the first layer is imidized and represented by the following formula (3A). It is the layer which consists of a block polyimide containing the block comprised by the repeating structural unit and the block comprised by the repeating structural unit represented by following formula (3B).

R ⁶ in the above formula (3A) is a tetravalent group similar to R ¹ in the above formula (1A). R ⁷ and R ⁸ in the above formula (3B) are the same divalent group or tetravalent group as R ² and R ³ in the above formula (1B), respectively. Further, m and n are the same as the values specified by the above formulas (1A) and (1B).
In addition, the 1st block polyimide layer 2 and 2nd block polyimide layer 2 'may differ.

上記式（４）におけるＲ^９及びＲ^１０は、それぞれ前記式（２）におけるＲ^４及びＲ^５と同様の２価の基または４価の基である。なお、熱可塑性ポリイミド層３は、異なる第２層同士が積層されて一層となったものであってもよい。 The thermoplastic polyimide layer 3 is a layer formed by laminating two layers of the second layer described above, and is a layer obtained by imidizing the amic acid used for the production of the second layer. That is, it is a layer made of polyimide composed of repeating structural units represented by the following formula (4).

R ⁹ and R ¹⁰ in the above formula (4) are the same divalent group or tetravalent group as R ⁴ and R ⁵ in the above formula (2), respectively. The thermoplastic polyimide layer 3 may be a single layer formed by stacking different second layers.

  In this heat-resistant double-sided metal laminate, the peel strength between the first metal foil and the first block polyimide layer and the peel strength between the second metal foil and the second block polyimide layer are 0.5 kN / m or more, respectively. Is preferable, more preferably 0.7 kN / m or more, and still more preferably 1.0 kN / m or more. By making the peel strength equal to or higher than the above value, it leads to circuit reliability when the heat-resistant double-sided metal laminate is used as a circuit board. The peel strength can be adjusted by the temperature and pressure at the time of thermocompression bonding of the laminate, the temperature increase rate when the coating film of the block polyamic acid imide solution is heated and dried, and the like.

  Further, the heat-resistant double-sided metal laminate preferably has no change in surface state during soldering work, and preferably has no change in form after being immersed in a 260 ° C. solder bath for 10 seconds. The change in form can be observed visually. The shape stability can be adjusted by the amount of cyclohexanediamine unit in the block polyimide layer.

  Further, the dimensional change rate after etching the metal foil of the heat-resistant double-sided metal laminate is preferably 0.2% or less, more preferably 0.1% or less, and still more preferably 0.05% or less. . When the dimensional change rate after etching of the metal foil is set to the above value or less, the fine workability and the like are improved, and the heat-resistant double-sided metal laminate can be applied to various wiring boards and the like. The shape stability can be adjusted by the amount of cyclohexanediamine unit in the block polyimide layer. The dimensional stability is a value measured by the following method.

  A heat-resistant double-sided metal laminate having a predetermined size (10 cm × 10 cm) is prepared, and holes are made in four directions (four corners) of the base material. Thereafter, all the metal foils on both sides are removed by etching and left in an atmosphere of 50% humidity and 23 ° C. for 24 hours. Thereafter, the rate of change in the distance between the holes formed is measured. The distance between holes is measured in each of the directions parallel to the sides of the heat-resistant transparent film, that is, the four directions, and the dimensional change rate is calculated from the average value of these change rates.

  Further, in the heat-resistant double-sided metal laminate, the total light transmittance after etching the metal foil is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. If the total light transmittance is not less than the above value, the heat-resistant double-sided metal laminate can be used in various applications where transparency is required. The total light transmittance can be adjusted by increasing the amount of cyclohexanediamine unit in the block polyimide layer or by the kind of diamine unit constituting the thermoplastic polyimide layer. Moreover, total light transmittance can also be improved by adjusting the temperature at the time of carrying out the thermocompression bonding of the two laminated bodies which consist of metal foil, a 1st layer, and a 2nd layer. Furthermore, the total light transmittance can be increased by reducing the oxygen concentration in the environmental atmosphere when the coating film of the block polyamic acid imide solution is heated and dried.

(Use)
The heat-resistant double-sided metal laminate of the present invention has high peel strength between the metal foil and the block polyimide layer, and is excellent in dimensional stability and transparency after etching of the metal foil. Therefore, it can be used as various heat-resistant transparent circuit boards and the like, and can be excellent in electrical reliability even when fine processing is performed by etching, drilling, or the like. It is also possible to etch the metal foil and use it as a heat resistant transparent film.
Etching can be performed by a conventionally known method, and an etching solution used for etching can be appropriately selected according to the type of the metal foil.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by this.

Abbreviations of compounds used in Examples and Comparative Examples are as follows.
[Diamine]
CHDA: 1,4-diaminocyclohexane NBDA: norbornanediamine 14BAC: 1,4-bis (aminomethyl) cyclohexane ODA: 4,4'-diaminodiphenyl ether 13BAC: 1,3-bis (aminomethyl) cyclohexane APB: 1,3 -Bis (3-aminophenoxy) benzene

[Tetracarboxylic dianhydride]
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride PMDA: pyromellitic dianhydride ODPA: bis (3,4-dicarboxyphenyl) ether dianhydride BTDA: 3,3 ′, 4,4'-benzophenonetetracarboxylic dianhydride

[solvent]
NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide

By the following method, the thermal expansion coefficient and glass transition temperature of the polyimide obtained from the varnish produced in the following synthesis examples 1 to 6 and the coating surface when the varnish was applied and formed were confirmed.
-Coefficient of thermal expansion (CTE) and glass transition temperature (Tg)
The single-layer metal laminated plate obtained by coating and drying a block polyamic acid imide solution (or block polyamic acid solution) on a metal foil was etched. The obtained heat-resistant transparent film has a coefficient of thermal expansion (CTE) and a glass transition temperature (Tg) of TMA-50 manufactured by Shimadzu Corporation, a heating rate of 5 ° C./min, and a load per unit cross-sectional area of 14 g / mm. Measured in ² . CTE was an average expansion coefficient in a range of 100 to 200 ° C., and Tg was evaluated for a tangential intersection of inflection points.

-Confirmation of coating surface state The state of the coating surface of the single-layer metal laminated board which apply | coated and dried the block polyamic-acid imide solution (or block polyamic-acid solution) on metal foil was observed visually. A case where no wrinkles or foaming was observed on the surface was judged as good (◯), and a case where foaming or the like was observed on the surface was judged as poor (x).

By the following method, the glass transition temperature of the polyimide obtained from the varnish produced in the synthesis examples 7-9 was measured.
-Measurement of glass transition temperature (Tg) The block amic acid solution was apply | coated to the glass plate. About this, it measured with the temperature increase rate of 5 degree-C / min and the load per unit cross-sectional area of 14 g / mm < ² > using Shimadzu TMA-50 type | mold, and evaluated each tangent intersection of an inflection point, and computed Tg .

[Synthesis 1 of block polyamic acid imide for first layer (Synthesis Example 1)]
・ Synthesis of amic acid oligomer varnish 1
In a 300 mL 5-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube, 11.4 g (0.100 mol) of CHDA and 116 g of NMP as a solvent were added and stirred. To the place where the solution was made transparent, 27.1 g (0.092 mol) of BPDA was charged in powder form, and the reaction vessel was bathed in an oil bath maintained at 120 ° C. for 5 minutes. After a while after the BPDA was charged, the salt precipitated, but then the salt dissolved to become a homogeneous system and the viscosity increased. After removing the oil bath, the mixture was further stirred at room temperature for 18 hours to obtain an amic acid oligomer varnish having a terminal amino group derived from CHDA.

・ Synthesis of imide oligomer varnish 1
NBDA 11.1 g (0.072 mol) and NMP 94.5 g were added to a 300 mL five-necked separable flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube and stirred. To the place where the solution was made clear, 29.4 g (0.100 mol) of BPDA was charged in powder form, and the reaction vessel was bathed in an oil bath maintained at 120 ° C. for 5 minutes. After the BPDA was charged, the salt temporarily precipitated, but it was confirmed that it immediately re-dissolved with a viscosity increase and became a uniform transparent solution.
A cooling tube and a Dean-Stark type concentrator were attached to the separable flask, 80.0 g of xylene was added to the reaction solution, and dehydration thermal imidization reaction was carried out at 180 ° C. with stirring for 4 hours. After distilling off xylene, an imide oligomer varnish having a BPDA-derived acid anhydride structure at the end was obtained.

・ Synthesis of block polyamic acid imide varnish 1
40.0 g of the amide acid oligomer varnish obtained in Synthesis 1 of the amide acid oligomer varnish and 9.99 g of the imide oligomer varnish obtained in Synthesis 1 of the imide oligomer varnish were mixed, and a high-viscosity material stirring defoaming mixer (stock) The product was stirred for a total of 10 minutes using a company Japan Unix Co., Ltd., product name: UM-118) to obtain a block polyamic acid imide varnish.

[Synthesis 2 of Block Polyamic Acid Imide for First Layer (Synthesis Example 2)]
・ Synthesis of amic acid oligomer varnish 2
The same operation was performed for synthesis 1 of the amic acid oligomer varnish except that CHDA 11.4 g (0.100 mol), NMP 113 g, and BPDA 25.9 g (0.088 mol) were used. Thus, an amic acid oligomer varnish having an amino group was obtained.

・ Synthesis of imide oligomer varnish 2
For imide oligomer varnish synthesis 1, the same procedure was followed, except for NBDA 11.8 g (0.077 mol), NMP 96.1 g, BPDA 29.4 g (0.100 mol), and xylene 80.0 g. And an imide oligomer varnish having a BPDA-derived acid anhydride structure at the end was obtained.

・ Synthesis of block polyamic acid imide varnish 2
40.0 g of the amide acid oligomer varnish obtained in Synthesis 2 of the amide acid oligomer varnish and 19.1 g of the imide oligomer varnish obtained in Synthesis 2 of the imide oligomer varnish 2 were mixed, and a high-viscosity material stirring defoaming mixer (stock) The product was stirred for a total of 10 minutes using a company Japan Unix Co., Ltd., product name: UM-118) to obtain a block polyamic acid imide varnish.

[Synthesis 3 of Polyamic Acid Varnish for First Layer (Synthesis Example 3)]
To a 300 mL 5-neck separable flask equipped with a thermometer, a stirrer, a nitrogen introducing tube, and a dropping funnel, 15.7 g (0.110 mol) of 14BAC and 192 g of DMAc were added and stirred.
Here, 32.4 g (0.110 mol) of powdery BPDA was charged, and the reaction vessel was bathed in an oil bath maintained at 120 ° C. for 5 minutes. After BPDA was charged, salt precipitation occurred in about 3 minutes. Thereafter, it was confirmed that it was quickly redissolved. After removing the oil bath, the mixture was further stirred at room temperature for 18 hours to obtain a polyamic acid varnish.

[Synthesis 4 of Polyamic Acid Varnish for First Layer (Synthesis Example 4)]
PMDA 39.7 g (0.180 mol) and DMAc 130 g were added to a 300 mL five-necked separable flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube to prepare a slurry solution. To this, a mixed solution of 27.8 g (0.180 mol) of NBDA and 27.8 g of DMAc was gradually added dropwise over 120 minutes so as not to generate heat. The mixture was then stirred at 50 ° C. for 5 hours to obtain a polyamic acid varnish.

[Synthesis 5 of Polyamic Acid Varnish for First Layer (Synthesis Example 5)]
ODPA 46.5 g (0.150 mol) and DMAc 139 g were added to a 300 mL five-necked separable flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube to prepare a slurry solution. To this, a mixed solution of 23.1 g (0.150 mol) of NBDA and 23.1 g of DMAc was gradually added dropwise over 120 minutes so as not to generate heat. Thereafter, the mixture was stirred at 50 ° C. for 5 hours to obtain a polyamic acid varnish.

[Synthesis 6 of Polyamic Acid Varnish for First Layer (Synthesis Example 6)]
In a 300 mL 5-neck separable flask equipped with a thermometer, a stirrer, and a nitrogen introduction tube, 10.0 g (0.050 mol) of ODA and 119 g of DMAc were added and stirred to obtain a uniform solution. Here, 10.9 g (0.050 mol) of PMDA was charged in a powder form so as not to generate heat. Thereafter, the mixture was stirred at 50 ° C. for 5 hours to obtain a polyamic acid varnish.

[Synthesis 7 of Polyamic Acid Varnish for Second Layer (Synthesis Example 7)]
To the polyamic acid varnish obtained in the same manner as in Synthesis Example 5, 232 g of DMAc was added for dilution to obtain a diluted polyamic acid varnish.

[Synthesis 8 of Polyamic Acid Varnish for Second Layer (Synthesis Example 8)]
4300 g (0.150 mol) of ODPA and 137 g of DMAc were added to a 300 mL five-necked separable flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube to prepare a slurry solution. To this, a mixed solution of 21.3 g (0.150 mol) of 13BAC and 21.3 g of DMAc was gradually added dropwise over 120 minutes so as not to generate heat. Thereafter, the mixture was stirred at 50 ° C. for 5 hours to obtain a polyamic acid varnish, and further diluted with 226 g of DMAc to obtain a diluted polyamic acid varnish.

[Synthesis 9 of Polyamic Acid Varnish for Second Layer (Synthesis Example 9)]
APB 11.7 g (0.040 mol) and DMAc 139 g were added to a 300 mL five-necked separable flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube to obtain a homogeneous solution. Here, 12.9 g (0.040 mol) of BTDA was charged in a powder form so as not to generate heat. Thereafter, the mixture was stirred at 50 ° C. for 5 hours to obtain a dilute polyamic acid varnish.

  The peel strength, solder resistance, dimensional change rate, and total light transmittance were measured for the heat-resistant double-sided metal laminates prepared in Examples 1 to 7 and Comparative Examples 1 to 7 described below.

-Peel strength A conductor with a length of 50 mm and a width of 3.5 mm is formed by etching a heat-resistant double-sided metal laminate, and the conductor side from the end of the short side is taken from the polyimide layer according to the method specified in JIS C-6471. Peeling was performed at a peeling angle of 90 ° and a peeling speed of 50 mm / min, and the stress was measured (Shimadzu Corporation tensile tester EZ-S, using an adhesive tape peeling tester).

Solder resistance Solder resistance is defined as the solder heat resistance temperature: IPC-TM-650 (The institute for Interconnecting and Packaging Electronic Circuits) No. Measured according to 2.4.13. Specifically, the heat-resistant double-sided metal laminate was floated in a 260 ° C. solder bath for 10 seconds. Thereafter, the presence / absence of blistering was visually confirmed, and the case where no blistering was observed was evaluated as good (◯), and the case where blistering was observed was regarded as defective (×).

-Dimensional change rate A heat-resistant double-sided metal laminate having a predetermined size (10 cm x 10 cm) was prepared, and holes were formed in four sides (four corners) of the base material, and then the metal foils on both sides were removed by etching. The obtained heat-resistant transparent film was allowed to stand 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 distance between holes was measured for each direction parallel to each side of the heat-resistant transparent film, that is, four directions, and the dimensional change rate was calculated from the average value of these change rates.

-Total light transmittance The heat-resistant transparent film obtained by etching and removing the metal foil of the heat-resistant double-sided metal laminate was measured using HZ-2 (TM double beam system) manufactured by Suga Test Instruments Co., Ltd. Aperture diameter: Φ20 mm, light source: D65.

Example 1
The block polyamic acid imide varnish synthesized in Synthesis Example 1 was dried on a copper foil 1 (manufactured by JX Nippon Mining &Metals; BHY-22BT, thickness 18 μm, mat surface Rz 0.8 μm) using a doctor blade. Coating was performed so that the thickness was 10 μm. Thereafter, the oxygen concentration in the layer is controlled to 0.5% using an inert oven, the temperature is raised from 30 ° C. to 270 ° C. over 120 minutes (temperature increase rate 2 ° C./min), and further at 270 ° C. for 1 hour. Holding, a single-layer metal laminate plate made of a metal foil and a first layer was obtained. The single-layer heat-resistant transparent film obtained by etching the obtained single-layer metal laminate with a ferric chloride solution had a CTE of 16 ppm / K and a Tg of 286 ° C.

The diluted polyamic acid varnish synthesized in Synthesis Example 7 was applied onto the single-layer metal laminate using a doctor blade so that the thickness after drying was 2 μm. It dried similarly to the said 1st layer, and obtained the laminated body by which the metal foil, the 1st layer, and the 2nd layer were laminated | stacked in this order.
Two pieces of the laminate were cut into 10 cm × 10 cm, and the second layers were combined. This was hot-pressed at 270 ° C. and 3 MPa for 1 hour to obtain a heat-resistant double-sided metal laminate. The resulting heat-resistant double-sided metal laminate had a peel strength of 1.00 kN / m, a dimensional change rate of -0.04%, and a total light transmittance of 83%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Example 2
Various samples were produced in the same manner as in Example 1 except that the temperature was increased from 30 ° C. to 270 ° C. over 30 minutes (temperature increase rate: 8 ° C./min). The CTE of the single-layer heat-resistant transparent film was 17 ppm / K, and Tg was 283 ° C. The peel strength of the heat-resistant double-sided metal laminate was 0.78 kN / m, the dimensional change was 0.03%, and the total light transmittance was 82%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Example 3
Various samples were prepared in the same manner as in Example 1 except that the block polyamic acid imide varnish synthesized in Synthesis Example 2 was used for the first layer. The CTE of the single-layer heat-resistant transparent film was 17 ppm / K, and Tg was 277 ° C. The peel strength of the heat-resistant double-sided metal laminate was 1.02 kN / m, the dimensional change was -0.05%, and the total light transmittance was 83%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Example 4
A heat-resistant double-sided metal laminate was produced in the same manner as in Example 1 except that the dilute polyamic acid varnish synthesized in Synthesis Example 8 was used for the second layer. The peel strength of the heat-resistant double-sided metal laminate was 0.81 kN / m, the dimensional change was -0.04%, and the total light transmittance was 83%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Example 5
Various samples were prepared in the same manner as in Example 1 except that the copper foil was changed to copper foil 2 (manufactured by Mitsui Metal Mining Co., Ltd .; NA-DFF, thickness 12 μm, mat surface Rz 0.4 μm). The CTE of the single-layer heat-resistant transparent film was 17 ppm / K, and Tg was 285 ° C. The peel strength of the heat-resistant double-sided metal laminate was 0.60 kN / m, the dimensional change was -0.05%, and the total light transmittance was 85%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Comparative example 1
A single-layer heat-resistant transparent film was produced in the same manner as in Example 1 except that the oxygen concentration in the environmental atmosphere during heating and drying of the polyamic acid imide varnish was 15.5%. The obtained single-layer heat-resistant transparent film had a CTE of 19 ppm / K and a Tg of 277 ° C. Further, when the diluted polyamic acid varnish synthesized in Synthesis Example 7 was applied on the obtained single-layer metal laminate, it was repelled mostly and it was difficult to laminate the second layer. A heat-resistant double-sided metal laminate was prepared in the same manner as in Example 1 using the part that was able to be laminated, and the total light transmittance was measured. As a result, it was 74%, and coloring was confirmed (peel strength, dimensional change rate). , Solder resistance could not be evaluated).

Comparative example 2
A heat-resistant double-sided metal laminate was produced in the same manner as in Example 1 except that the hot pressing temperature was 220 ° C. The dimensional change was -0.01%, and the total light transmittance was 83%. However, the peel strength was as low as 0.07 kN / m, and swelling was confirmed in the sample after a solder bath float at 260 ° C. for 10 seconds.

Comparative example 3
A heat-resistant double-sided metal laminate was produced in the same manner as in Example 1 except that the hot pressing temperature was 320 ° C. The resulting heat-resistant double-sided metal laminate was foamed and colored (total light transmittance was 79%). The peel strength of the heat-resistant double-sided metal laminate was 0.75 kN / m, and the dimensional change rate was 0.02%. Further, swelling was confirmed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Comparative example 4
Various samples were prepared in the same manner as in Example 1 except that the polyamic acid varnish synthesized in Synthesis Example 3 was used for the first layer. The CTE of the single-layer heat-resistant transparent film was 48 ppm / K, and Tg was 260 ° C. The peel strength of the heat-resistant double-sided metal laminate was 0.78 kN / m, and the total light transmittance was 85%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds. However, the dimensional change rate was as high as 0.35%.

Comparative example 5
Various samples were prepared in the same manner as in Example 1 except that the polyamic acid varnish synthesized in Synthesis Example 4 was used for the first layer. The CTE of the single-layer heat-resistant transparent film was 50 ppm / K, and Tg was 290 ° C. The peel strength of the heat-resistant double-sided metal laminate was 0.56 kN / m, and the total light transmittance was 86%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds. However, the dimensional change rate was as high as 0.37%.

Comparative Example 6
Various samples were prepared in the same manner as in Example 1 except that the polyamic acid varnish synthesized in Synthesis Example 5 was used for the first layer. The CTE of the single-layer heat-resistant transparent film was 55 ppm / K, and Tg was 221 ° C. The peel strength of the heat-resistant double-sided metal laminate was 1.65 kN / m, and the total light transmittance was 89%. However, the rate of dimensional change was -0.43%, and swelling and wrinkling of the film itself were confirmed in the sample after the solder bath float at 260 ° C. for 10 seconds.

Comparative example 7
Various samples were prepared in the same manner as in Example 1 except that the polyamic acid varnish synthesized in Synthesis Example 6 was used for the first layer. The CTE of the single-layer heat-resistant transparent film was 22 ppm / K, and Tg was 289 ° C. The dimensional change rate of the heat-resistant double-sided metal laminate was −0.18%. However, the peel strength was as low as 0.32 kN / m, and swelling was confirmed in the sample after a solder bath float at 260 ° C. for 10 seconds. Further, the total light transmittance was 71%, and coloring was also confirmed.

Example 6
A heat-resistant double-sided metal laminate was produced in the same manner as in Example 1 except that the dilute polyamic acid varnish synthesized in Synthesis Example 9 was used for the second layer. The peel strength was 1.22 kN / m, and the dimensional change rate was -0.02%. Further, no swelling was observed in the sample after the solder bath float at 260 ° C. for 10 seconds. However, the total light transmittance was 78%, and it was confirmed that it was colored.

-Example 7
Example 1 except that the sample coated with the first layer was placed in an inert oven heated to 270 ° C. and heated in a short time (2 minutes) (corresponding to a heating rate of 120 ° C./min). In the same manner, a single-layer heat-resistant transparent film was produced. The obtained single-layer heat-resistant transparent film had a CTE of 26 ppm / K and a Tg of 263 ° C. Moreover, the surface of the obtained single-layer metal laminated plate was found to have a skin and whitening, and the surface condition was poor.
In addition, the heat-resistant double-sided metal laminate obtained in the same manner as in Example 1 had the remaining yuzu skin and whitening, and the total light transmittance was 77%. The peel strength of the heat-resistant double-sided board laminate was as low as 0.10 kN / m, and the dimensional change rate was as high as -0.38%. Further, swelling was confirmed in the sample after the solder bath floated at 260 ° C. for 10 seconds.

[Evaluation]
When the first layer was prepared using a block polyamic acid imide varnish containing a cyclohexanediamine unit, the peel strength between the metal layer and the block polyimide layer was high, and the dimensional change after etching the metal layer was small. (Examples 1 to 5). On the other hand, when the 1st layer was produced using the block polyamic-acid varnish which does not contain a cyclohexanediamine unit, the dimensional change was large (Comparative Examples 4-6).

  Moreover, when the temperature at the time of thermocompression bonding of two laminated bodies is too low, the peel strength is not sufficient (Comparative Example 2), and when the temperature at the time of thermocompression bonding is too high, the peel strength is sufficient. However, the solder heat resistance and the surface condition deteriorated (Comparative Example 3).

  Moreover, when producing a 2nd layer using the polyamic acid containing an alicyclic diamine unit (Examples 1-5), when producing a 2nd layer using the polyamic acid containing an aromatic diamine unit (implementation) Compared with Example 6), the total light transmittance was improved.

  In addition, when the drying temperature of the polyamic acid imide coating was rapidly increased during the formation of the first layer, the surface condition was poor, the dimensional stability was poor, and the peel strength was also reduced (Example 7). . When the first layer was formed, if the oxygen concentration was very high, it was difficult to form the second layer, and the total light transmittance was also low (Comparative Example 1).

  In the heat-resistant double-sided metal laminate of the present invention, metal foil is laminated on both sides of the block polyimide layer, and the peel strength between the metal foil and the block polyimide is high. Moreover, the transparency after etching the metal foil is high, and the dimensional stability is also excellent. Therefore, the heat-resistant double-sided metal laminate of the present invention is very useful for applications such as various wiring boards and various board films.

DESCRIPTION OF SYMBOLS 10 Heat-resistant double-sided metal laminated board 1 1st metal foil 1 '2nd metal foil 2 1st block polyimide layer 2' 2nd block polyimide layer 3 Thermoplastic polyimide layer

Claims (7)

Metal foil,
A block polyamic acid imide containing a block composed of a repeating structural unit represented by the following formula (1A) and a block composed of a repeating structural unit represented by the following formula (1B) and a block polyamic acid containing a solvent A first layer obtained by applying an imide solution onto the metal foil and heating the coating film to 230 ° C. or higher in an environmental atmosphere having an oxygen concentration of 1% or less;
A polyamic acid solution containing a polyamic acid and a solvent having a glass transition temperature of 150 to 250 ° C. and comprising a repeating structural unit represented by the following formula (2) is applied onto the first layer, and dried by heating. Two laminated bodies having a second layer obtained by
A heat-resistant double-sided metal laminate obtained by facing the second layers and thermocompression bonding at 250 to 300 ° C.

(In Formula (1A) or Formula (1B),
m represents the number of repeating structural units represented by the formula (1A),
n represents the number of repeating structural units represented by the formula (1B),
And average value of m: average value of n = 1: 9 to 9: 1,
R ¹ and R ³ are each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, or a monocyclic aromatic group Or a condensed polycyclic aromatic group, a cyclic aliphatic group is a non-condensed polycyclic aliphatic group linked directly or by a bridging member, or an aromatic group is directly or by a bridging member Non-fused polycyclic aromatic groups linked to each other;
R ² is a divalent group having 4 to 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group (excluding a 1,4-cyclohexylene group), a condensed polycyclic aliphatic group A monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group in which the cyclic aliphatic groups are connected to each other directly or by a bridging member, or aromatic A non-condensed polycyclic aromatic group in which the groups are connected to each other directly or by a bridging member)

(In Formula (2),
R ⁴ is a divalent group having ^{4 to} 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed polycyclic aromatic group. A non-condensed polycyclic aliphatic group in which the cyclic aliphatic group is directly or linked to each other by a bridging member, or a non-condensed group in which aromatic groups are linked to each other directly or by a bridging member A polycyclic aromatic group,
R ⁵ is each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed poly group. A cyclic aromatic group, a non-condensed polycyclic aliphatic group in which the cycloaliphatic groups are directly or mutually linked by a bridging member, or an aromatic group that is linked directly or by a bridging member Non-condensed polycyclic aromatic group)   2. The heat-resistant double-sided metal laminate according to claim 1, wherein an average temperature increase rate in a temperature range of 150 to 300 ° C. is 0.25 to 50 ° C./min during heating and drying of the coating film of the block polyamic acid imide solution. Board.   The heat-resistant double-sided metal laminate according to claim 1 or 2, wherein the metal foil is a copper foil having a surface 10-point average roughness (Rz) of 3 µm or less. The peel strength between the metal foil and the first layer is 0.5 kN / m or more,
No change in shape after bathing in 260 ° C solder for 10 seconds,
The dimensional change rate after etching of the metal foil is 0.2% or less,
The heat-resistant double-sided metal laminate according to any one of claims 1 to 3, wherein the total light transmittance after etching of the metal foil is 80% or more. The heat-resistant transparent film obtained by etching the heat-resistant double-sided metal laminated plate as described in any one of Claims 1-4 . The heat-resistant transparent circuit board obtained by etching the heat-resistant double-sided metal laminated plate as described in any one of Claims 1-4 . The first metal foil, the first block polyimide layer, the thermoplastic polyimide layer, the second block polyimide layer, and the second metal foil are a method for producing a heat-resistant double-sided metal laminate in which the second metal foil is laminated in this order,
Block polyamic acid imide containing a block composed of a repeating structural unit represented by the following formula (1A) and a block composed of a repeating structural unit represented by the following formula (1B) and a block polyamic acid imide containing a solvent Applying the solution on a metal foil and heating the coating film to a temperature of 230 ° C. or higher in an environmental atmosphere having an oxygen concentration of 1% or less to form a first layer;
A polyamic acid solution containing a polyamic acid and a solvent having a glass transition temperature of 150 to 250 ° C. and composed of repeating structural units represented by the following formula (2) is applied onto the first layer, and then dried by heating. Forming the second layer
Preparing two laminates composed of the metal foil, the first layer, and the second layer, facing the second layers of the laminate, and thermocompression bonding at 250 to 300 ° C .;
A method for producing a heat-resistant double-sided metal laminate including:

(In Formula (1A) or Formula (1B),
m represents the number of repeating structural units represented by the formula (1A),
n represents the number of repeating structural units represented by the formula (1B),
And average value of m: average value of n = 1: 9 to 9: 1,
R ¹ and R ³ are each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, or a monocyclic aromatic group Or a condensed polycyclic aromatic group, a cyclic aliphatic group is a non-condensed polycyclic aliphatic group linked directly or by a bridging member, or an aromatic group is directly or by a bridging member Non-fused polycyclic aromatic groups linked to each other;
R ² is a divalent group having 4 to 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group (excluding a 1,4-cyclohexylene group), a condensed polycyclic aliphatic group A monocyclic aromatic group or a condensed polycyclic aromatic group, or a non-condensed polycyclic aliphatic group in which the cyclic aliphatic groups are connected to each other directly or by a bridging member, or aromatic A non-condensed polycyclic aromatic group in which the groups are connected to each other directly or by a bridging member)

(In Formula (2),
R ⁴ is a divalent group having ^{4 to} 51 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed polycyclic aromatic group. A non-condensed polycyclic aliphatic group in which the cyclic aliphatic group is directly or linked to each other by a bridging member, or a non-condensed group in which aromatic groups are linked to each other directly or by a bridging member A polycyclic aromatic group,
R ⁵ is each independently a tetravalent group having 4 to 27 carbon atoms; and an aliphatic group, a monocyclic aliphatic group, a condensed polycyclic aliphatic group, a monocyclic aromatic group, or a condensed poly group. A cyclic aromatic group, a non-condensed polycyclic aliphatic group in which the cycloaliphatic groups are directly or mutually linked by a bridging member, or an aromatic group that is linked directly or by a bridging member Non-condensed polycyclic aromatic group)

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