Flexible printed circuit board

• US 9,942,979 B2
• Filed: 11/03/2015
• Issued: 04/10/2018
• Est. Priority Date: 11/03/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group), SungKyunKwan University's Research & Business Foundation (SungKyunKwan University (SKKU))
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group), SungKyunKwan University's Research & Business Foundation (SungKyunKwan University (SKKU))
• Inventors: Park, Kyung-wan, Cho, Shi-yun, Lee, Hyo-young, Kim, Hyun-jung, Kim, Mee-ree, Kim, Ik-joon
• Primary Examiner(s): Chen, Xiaoliang
• Application Number:
  US14/930,866
• Publication Number:
  US 20160128182A1
• Time in Patent Office: 889 Days
• Field of Search: 174254, 174250, 174253, 174257, 156 60, 117 68, 428161, 428164, 428215, 428336, 428339, 428364, 428367, 349 43
• CPC Class Codes: B32B 2250/24 All layers being polymeric
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/24 Organic non-macromolecular coating
• CPC Class Codes: B32B 2262/103 Metal fibres
• CPC Class Codes: B32B 2270/00 Resin or rubber layer containing a blend of at least two different polymers
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 2307/51 Elastic
• CPC Class Codes: B32B 2307/546 Flexural strength; Flexion stiffness
• CPC Class Codes: B32B 2457/08 PCBs, i.e. printed circuit boards
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/281 comprising polyimides
• CPC Class Codes: B32B 27/283 comprising polysiloxanes
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 3/08 characterised by added members at particular parts layer formed of separate pieces of material which are juxtaposed side-by-side B32B3/14, B32B3/18
• CPC Class Codes: B32B 7/05 the layers not being connected over the whole surface, e.g. discontinuous connection or patterned connection using interposed adhesives or bonding materials applied in spaced arrangements B32B7/14
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/097 : Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 2201/0133 : Elastomeric or compliant polymer elastomeric conductor H05K2201/0314
• CPC Class Codes: H05K 2201/0145 : Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN]
• CPC Class Codes: H05K 2201/0154 : Polyimide
• CPC Class Codes: H05K 2201/0162 : Silicon containing polymer, e.g. silicone
• CPC Class Codes: H05K 2201/026 : Nanotubes or nanowires
• CPC Class Codes: H05K 3/389 : by the use of a coupling agent, e.g. silane

Abstract

A flexible printed circuit board (PCB) has stretchability and durability. The flexible PCB includes: a first polymer substrate having flexibility, stretchability, or elasticity; a second polymer substrate having flexibility, stretchability, or elasticity; a conductive track disposed between the first and second polymer substrates and including metal nanowires; and a cured silane coupling agent which bonds the conductive track to at least one of the first and second polymer substrates.

Claims

1. A flexible printed circuit board (PCB) comprising:

a first polymer substrate having at least one of flexibility, stretchability, and elasticity;

a second polymer substrate having at least one of flexibility, stretchability, and elasticity;

a conductive track comprising metal nanowires disposed between the first polymer substrate and the second polymer substrate; and

a cured silane coupling agent configured to bond the conductive track to at least one of the first polymer substrate and the second polymer substrate,

wherein the metal nanowires comprise at least one of silver (Ag), gold (Au), copper (Cu), platinum (Pt), palladium (Pd), nickel (Ni), cobalt (Co), and an alloy thereof, and

wherein the metal nanowires are in contact with each other, thereby maintaining an electrically conductive network along an entirety of the conductive track, and

wherein the first polymer substrate and the second polymer substrate each comprise at least one of a polyamide-based resin, polyester-based resin, a polyethylene-based resin, a polypropylene-based resin, and a polycarbonate-based resin.

2. The flexible PCB of claim 1, wherein the first polymer substrate and the second polymer substrate each have a thickness in a range of about 10 μ

m to about 3,000 μ

m.

3. The flexible PCB of claim 1, wherein the metal nanowires have an average aspect ratio in a range of about 20 to about 300.

4. The flexible PCB of claim 1, wherein the metal nanowires have an average diameter in a range of about 1 nm to about 500 nm.

5. The flexible PCB of claim 1, wherein the metal nanowires have an average length in a range of about 5 μ

m to about 30 μ

m.

6. The flexible PCB of claim 1, wherein the metal nanowires disposed in the conductive track have an average population density in a range of about 100 per square centimeter to about 200,000 per square centimeter.

7. The flexible PCB of claim 1, wherein the metal nanowires comprise Ag.

8. The flexible PCB of claim 1, wherein the cured silane coupling agent is produced from a silane coupling agent represented by a chemical formula of R_nSiX_(4-n), wherein X indicates a hydrolytic group and R is a non-hydrolytic organic radical.

9. The flexible PCB of claim 8, wherein R comprises at least one of an epoxy group, a (meth)acrylate group, an isocyanate group, a vinyl group, a styryl group, an amino group, an isocyanurate group, an ureide group, a mercapto group, and a sulfide group.

10. The flexible PCB of claim 8, wherein the silane coupling agent comprises at least one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane), 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltriethoxysilane, 5,6-epoxyhexyltriethoxysilane, (3-gly cidoxypropyl)methyldiethoxysilane, (3-glycidoxypropyl)methyldimethoxy silane, and (3-glycidoxypropyl)dimethylethoxysilane.

11. The flexible PCB of claim 8, wherein the silane coupling agent comprises at least one of 3-methacryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, N-(3-acryloxy-2-hydroxypropyl)-3-amino propyltriethoxysilane, O-(methacryloxyethyl)-N-(triethoxy-silylpropyl)urethane, N-(3-methacryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, methacryloxy methyltriethoxysilane, methacryloxymethyltrimethoxy-silane, methacryloxypropyl triethoxysilane, (3-acryloxypropyl)methyldimethoxysilane, (methacryloxymethyl) methyl-diethoxysilane, (methacryloxymethyl)methyl-dimethoxysilane, (meth)acryloxypropylmethyldi-ethoxysilane), methacryloxypropylmethyldi-methoxysilane, and methacryloxypropyldimethylethoxy-silane, methacryloxypropyldimethylmethoxy silane.

12. The flexible PCB of claim 8, wherein the silane coupling agent comprises at least one of isocyanotopropyltriethoxysilane, (isocyanatomethyl)methyldimethoxysilane, 3-isocyanatopropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl] isocyanurate, (3-triethoxysilylpropyl)-t-butylcarbamate, triethoxysilylpropylethylcarbamate, and 3-thiocyanatopropyl triethoxysilane.

13. The flexible PCB of claim 8, wherein the silane coupling agent comprises at least one of allyltrimethoxysilane, 3-(N-styryl methyl-2-aminoethylamino)-propyltrimethoxysilane, vinyltriacetoxy silane, vinyltriethoxysilane, vinyltriisopropenoxysilane, vinyltriisopropoxy silane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl trimethoxysilane, 4-aminobutyltriethoxysilane, m-aminophenyltrimethoxysilane, p-aminophenyltrimethoxysilane, aminophenyltrimethoxysilane, 3-aminopropyl tris(methoxyethoxy- ethoxy)silane, acetoxymethyltriethoxysilane, acetoxymethyl trimethoxysilane, acetoxypropyltrimethoxysilane, and benzoyloxypropyltrimethoxy silane.

14. The flexible PCB of claim 8, further comprising a conductive pad configured to be electrically in contact with the conductive track.