Method for producing film and flexible metal-clad laminate

Patent metadata

Field	Value
Publication number	US-2016183385-A1
Application number	US-201615057934-A
Country	US
Kind code	A1
Filing date	Mar 1, 2016
Priority date	Mar 20, 2007
Publication date	Jun 23, 2016
Grant date	—

Abstract

A film and a flexible metal-clad laminate obtained with the film. The laminate is improved in post-moisture absorption solderability. The film comprises a heat-resistant polyimide film and, disposed on at least one side thereof, an adhesive layer containing a thermoplastic polyimide. It is characterized in that the thermoplastic polyimide contained in the adhesive layer has crystallinity and that the film, when analyzed with a differential scanning calorimeter, has an endothermic peak attributable to the melting of the crystalline thermoplastic polyimide, the absolute value of the area of the peak being 4.0 mJ/mg or larger. The flexible metal-clad laminate is characterized by comprising the film and a metal layer disposed thereon.

First claim

1 - 14 . (canceled)

15 . A method for producing a film comprising an adhesive layer on at least one side surface of a heat-resistant polyimide film, the adhesive layer containing a thermoplastic polyimide, the thermoplastic polyimide being a crystalline thermoplastic polyimide, the film being such that an absolute value of an endothermic peak area attributed to melting of the crystalline thermoplastic polyimide is 4.0 mJ/mg or higher, the endothermic peak area being measured by performing a differential scanning calorimetry on the film, the crystalline thermoplastic polyimide being produced by a process comprising the following steps (a) to (d):
(a) reacting a first aromatic diamine with a first aromatic dianhydride in an organic polar solvent under a condition where the first aromatic diamine or the first aromatic dianhydride is contained in excess to obtain a prepolymer having an amino group or an acid anhydride group at both ends; (b) adding (i) a second aromatic diamine having a different structure from the first aromatic diamine used in (a) or (ii) a second aromatic dianhydride having a different structure from the first aromatic dianhydride used in (a); (c) adding (i) the second aromatic diamine having a different structure from the first aromatic diamine used in (a) if the second aromatic dianhydride is added in (b) or (ii) the second aromatic dianhydride having a different structure from the first aromatic dianhydride used in (a) if the second aromatic diamine is added in (b) so that the second aromatic diamine and the second aromatic dianhydride are contained in substantially equimolar amounts and then performing polymerization to obtain a polyamic acid; and (d) imidizing the polyamic acid.

16 . The method according to claim 15 , wherein an absolute value of an exothermic peak area attributed to recrystallization of the crystalline thermoplastic polyimide is 4.0 mJ/mg or lower, the exothermic peak area being measured by performing the differential scanning calorimetry on the film.

17 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide has a melting point within a range of 340° C. to 450° C.

18 . The method according to claim 15 , wherein a water absorption coefficient of the heat-resistant polyimide film is 1.5% or lower.

19 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide is obtained by imidizing a polyamic acid composed from a combination of a diamine component and a dianhydride component:
the diamine component being selected from the group consisting of 1,4-bis(4-aminophenoxy)benzene; 1,3-bis(4-aminophenoxy)benzene; 4,4′-bis(3-aminophenoxy)biphenyl; 4,4′-bis(4-aminophenoxy)biphenyl; 1,4-diaminobenzene; and 3,4′-diaminodiphenyl ether and the dianhydride component being selected from the group consisting of pyromellitic dianhydride; 3,3′,4,4′-biphenyl tetra carboxylic dianhydride; and 3,3′,4,4′-benzophenone tetra carboxylic dianhydride.

20 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide is contained in an amount of 85 wt % to 100 wt % with respect to the thermoplastic polyimide contained in the adhesive layer.

21 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide is produced by a process comprising the following steps (a) to (c):
(a) reacting the first aromatic diamine with the first aromatic dianhydride in the organic polar solvent under a condition where the first aromatic diamine is contained in excess to obtain a prepolymer having amino groups at both ends; (b) adding the second aromatic diamine having a different structure from the first aromatic diamine used in (a); (c) adding the second aromatic dianhydride having a different structure from the first aromatic dianhydride used in (a) so that the second aromatic diamine and the second aromatic dianhydride are contained in a substantially equimolar amount throughout all steps and then performing polymerization.

22 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide is produced by a process comprising the following steps (a) to (c):
(a) reacting the first aromatic diamine with the first aromatic dianhydride in the organic polar solvent under a condition where the first aromatic dianhydride is contained in excess to obtain a prepolymer having acid anhydride groups at both ends; (b) adding the second aromatic dianhydride having a different structure from the first aromatic dianhydride used in (a); (c) adding the second aromatic diamine having a different structure from the first aromatic diamine used in (a) so that the second aromatic diamine and second the aromatic dianhydride are contained in a substantially equimolar amount throughout all steps and then performing polymerization.

23 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide has a melting point at least 5° C. lower than a crystalline thermoplastic polyimide obtainable by imidizing (i) a polyamic acid obtained through a polymerization performed so that the first aromatic diamine used in the step (a) and the first aromatic dianhydride used in the step (a) are contained in a substantially equimolar amount or (ii) a polyamic acid obtained through a polymerization performed so that the second aromatic diamine used in the steps (b) and (c) and the second aromatic dianhydride used in the steps (b) and (c) are contained in a substantially equimolar amount.

24 . The method according to claim 15 , wherein the crystalline thermoplastic polyimide has a melting point within a range of 340° C. to 380° C.

25 . A method for producing a flexible metal-clad laminate, the method comprising forming a metal layer on at least one side surface of the film produced by the method as set forth in claim 15 .

26 . The method according to claim 25 , wherein the flexible metal-clad laminate meets both of the following conditions (i) and (ii):
(i) a peeling strength for the metal layer is 10 N/cm or greater, where a force to peel the metal layer is applied in a 180 degrees direction; and (ii) defective appearance such as swelling and whitening does not occur even if being exposed under a moisture condition of 40° C. of temperature and 90% R.H. for 96 hours and thereafter immersed in solder dip of 300° C. for 10 seconds.

27 . The method according to claim 25 , wherein the flexible metal-clad laminate is such that the film resulting from removal of the metal layer provided on the film by etching etc. is such that (i) an absolute value of an endothermic peak area attributed to melting of the crystalline thermoplastic polyimide is 4.0 mJ/mg or higher, the endothermic peak area being measured by performing a differential scanning calorimetry on the film, and (ii) an absolute value of an exothermic peak area attributed to recrystallization of the crystalline thermoplastic polyimide is 0.5 mJ/mg or lower, the exothermic peak area being measured by performing the differential scanning calorimetry on the film.

Assignees

• Kaneka Corp

Inventors

• Kikuchi Takashi
• Kondo Yasutaka

Classifications

• H05K3/06

  the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)} · CPC title

• H05K3/18

  using precipitation techniques to apply the conductive material · CPC title

• H05K3/146

  By vapour deposition · CPC title

• H05K3/386 Primary

  by the use of an organic polymeric bonding layer, e.g. adhesive · CPC title

• C09J2301/312

  parameters being the characterizing feature · CPC title