# US 10,375,836 B2 · Film and flexible metal-clad laminate

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- Number: US 10,375,836 B2
- Document ID: US10375836B2
- Status: Granted
- Kind: B2
- Application number: 15/866,547
- Filed: 2018-01-10
- Published: 2018-05-10
- Granted: 2019-08-06
- Earliest claimed: 2007-03-20
- Assignees: Kaneka Corporation
- Applicants: Kaneka Corporation
- Inventors: Takashi Kikuchi; Yasutaka Kondo
- Web page: https://patentgrep.com/patent/US10375836B2

## CPC

- H05K 3/386: {by the use of an organic polymeric bonding layer, e.g. adhesive}
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 15/08: of synthetic resin
- B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)}
- B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)}
- B32B 27/08: of synthetic resin
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/281: {comprising polyimides}
- C08G 73/1046: {Polyimides containing oxygen in the form of ether bonds in the main chain}
- C08G 73/105: {with oxygen only in the diamino moiety}
- C08G 73/1067: {Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound}
- C08G 73/1071: {Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain}
- C09J 7/25: based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
- C09J 179/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- H05K 1/0346: {containing N}
- H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)}
- H05K 3/146: {By vapour deposition}
- H05K 3/18: using precipitation techniques to apply the conductive material
- B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer
- B32B 2255/205: Metallic coating
- B32B 2255/26: Polymeric coating
- B32B 2307/306: Resistant to heat
- B32B 2307/546: Flexural strength; Flexion stiffness
- B32B 2307/704: Crystalline
- B32B 2307/7265: Non-permeable
- B32B 2457/08: PCBs, i.e. printed circuit boards
- C09J 2301/312: parameters being the characterizing feature
- C09J 2479/08: polyimide
- C09J 2479/086: in the substrate
- H05K 1/036: {Multilayers with layers of different types}
- H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)}
- H05K 2201/0129: Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
- H05K 2201/0154: Polyimide
- H05K 2201/0355: Metal foils
- Y10T 428/2896: including nitrogen containing condensation polymer [e.g., polyurethane, polyisocyanate, etc.]
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## 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.

## Claims

### Claim 1

A film, comprising:
a heat-resistant polyimide film; and
an adhesive layer on at least one side surface of the heat-resistant polyimide film, wherein the adhesive layer comprises a crystalline thermoplastic polyimide,
wherein the film shows an endothermic peak area attributed to melting of the crystalline thermoplastic polyimide in differential scanning calorimetry, and an absolute value of the endothermic peak area is 4.0 mJ/mg or higher,
wherein the crystalline thermoplastic polyimide is produced by a process comprising imidizing a polyamic acid obtained by reacting at least one diamine component and a dianhydride component,
wherein the at least one diamine component is selected from the group consisting of 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4′-bis(4-aminophenoxy)biphenyl, and
wherein the dianhydride component is 3,3′,4,4′-biphenyl tetra carboxylic dianhydride.

### Claim 2 (depends on 1)

The film according to claim 1, wherein the film shows an exothermic peak area attributed to recrystallization of the crystalline thermoplastic polyimide in differential scanning calorimetry, and an absolute value of the exothermic peak area is 4.0 mJ/mg or lower.

### Claim 3 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide has a melting point of from 340° C. to 450° C.

### Claim 4 (depends on 1)

The film according to claim 1, wherein the heat-resistant polyimide film has a water absorption coefficient of 1.5% or lower.

### Claim 5 (depends on 1)

The film according to claim 1, wherein an amount of the crystalline thermoplastic polyimide is from 85 wt % to 100 wt % with respect to a thermoplastic polyimide contained in the adhesive layer.

### Claim 6 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide has a melting point of from 340° C. to 380° C.

### Claim 7 (depends on 1)

A flexible metal-clad laminate, comprising:
the film of claim 1; and
a metal layer formed on at least one side surface of the film.

### Claim 8 (depends on 7)

The flexible metal-clad laminate according to claim 7, which has both of the following properties (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 that includes 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.

### Claim 9 (depends on 7)

The flexible metal-clad laminate according to claim 7, wherein the flexible metal-clad laminate is such that the film resulting from removal of the metal layer shows, by differential scanning calorimetry, an endothermic peak area attributed to melting of the crystalline thermoplastic polyimide and an exothermic peak area attributed to recrystallization of the crystalline thermoplastic polyimide, an absolute value of the endothermic peak is 4.0 mJ/mg or higher, and an absolute value of the exothermic peak area is 0.5 mJ/mg or lower.

### Claim 10 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide is produced by a process comprising imidizing a polyamic acid obtained by reacting 4,4′-bis(4-aminophenoxy)biphenyl and 3,3′,4,4′-biphenyl tetra carboxylic dianhydride.

### Claim 11 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide is produced by a process comprising imidizing a polyamic acid obtained by reacting 1,4-bis(4-aminophenoxy)benzene and 1,3-bis(4-aminophenoxy)benzene, and 3,3′,4,4′- biphenyl tetra carboxylic dianhydride.

### Claim 12 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide is produced by a process comprising imidizing a polyamic acid obtained by reacting 4,4′-bis(4-aminophenoxy)biphenyl and 1,3-bis(4-aminophenoxy)benzene, and 3,3′,4,4′-biphenyl tetra carboxylic dianhydride.

### Claim 13 (depends on 1)

The film according to claim 1, wherein the crystalline thermoplastic polyimide is produced by a process comprising imidizing a polyamic acid obtained by reacting 1,3-bis(4-aminophenoxy)benzene and 3,3′,4,4′-biphenyl tetra carboxylic dianhydride.