# US 2019/0376237 A1 · Aramid paper suitable for use in electronic applications

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- Number: US 2019/0376237 A1
- Document ID: US20190376237A1
- Status: Published application
- Kind: A1
- Application number: 16/464,534
- Filed: 2017-11-27
- Published: 2019-12-12
- Earliest claimed: 2016-11-30
- Assignees: Teijin Aramid B.V.
- Applicants: Teijin Aramid B.V.
- Inventors: Antonius HENDRIKS; Mónica LÓPEZ-LORENZO; Jan-Cees TIECKEN; Frank DIEDERING
- Web page: https://patentgrep.com/patent/US20190376237A1

## CPC

- D21H 13/26: Polyamides; Polyimides
- B32B 15/12: of paper or cardboard
- D04H 1/4342: Aromatic polyamides
- D04H 1/549: Polyamides
- D21H 17/48: with phenols
- H01B 3/52: wood; paper; press board
- H05K 1/0366: {reinforced, e.g. by fibres, fabrics (H05K1/036 takes precedence)}
- H10F 77/00: Constructional details of devices covered by this subclass (constructional details of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- B32B 15/00: Layered products comprising {a layer of} metal
- B32B 2457/08: PCBs, i.e. printed circuit boards
- B32B 2457/12: Photovoltaic modules
- H05K 3/022: {Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates}
- H05K 2201/0284: Paper, e.g. as reinforcement
- H05K 2201/0293: Non-woven fibrous reinforcement
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An aramid paper suitable for use in electronic applications which has a density of 0.20-0.65 g/cm3 and a grammage of 30-280 g/m2, which paper comprises 10-40 wt. % of aramid shortcut with a linear density of 2.6 dtex or lower and a length of 0.5-25 mm and 10-90 wt. % of aramid fibrid, wherein the aramid shortcut comprises at least 70 wt. % para-aramid shortcut and the aramid fibrid including at least 70 wt. % para-aramid fibrid. It has been found that the use of a paper with the above properties in electronic applications ensures a low CTE in combination with good homogeneity and a good dimensional stability resulting from good resin adhesion and penetration. Use of the aramid paper in a composite sheet including at least one layer of aramid paper and a resin, or in a substrate board for electronic applications.

## Claims

### Claim 1

Aramid paper suitable for use as substrate in electronic applications which has a density of 0.20-0.65 g/cm3 and a grammage of 30-280 g/m2, which paper comprises 10-40 wt. % of aramid shortcut with a linear density of 2.6 dtex or lower and a length of 0.5-25 mm and 10-90 wt. % of aramid fibrid, wherein the aramid shortcut comprises at least 70 wt. % para-aramid shortcut and the aramid fibrid comprises at least 70 wt. % para-aramid fibrid.

### Claim 2 (depends on 1)

Aramid paper according to claim 1, which has a density of at least 0.30 g/cm3.

### Claim 3 (depends on 1)

Aramid paper according to claim 1, which comprises at least 80 wt. % of aramid.

### Claim 4 (depends on 1)

Aramid paper according to claim 1, wherein the aramid comprises at least 85 wt. % of para-aramid.

### Claim 5 (depends on 1)

Aramid paper according to claim 1, which comprises at least 20 wt. % of aramid fibrid.

### Claim 6 (depends on 1)

Aramid paper according to claim 1, which comprises 10-40 wt. % of aramid shortcut in combination with 90-60 wt. % of aramid fibrid.

### Claim 7 (depends on 1)

Aramid paper according to claim 1, which comprises 10-40 wt. % of aramid shortcut in combination with 10-80 wt. % aramid fibrid and 10-80 wt. % of aramid pulp.

### Claim 8 (depends on 7)

Aramid paper according to claim 7, wherein the paper comprises 10-40 wt. % of aramid shortcut in combination with 20-80 wt. % aramid fibrid and 10-40 wt. % of aramid pulp.

### Claim 9 (depends on 1)

Composite sheet comprising at least one layer of aramid paper according to claim 1 impregnated with a resin.

### Claim 10 (depends on 9)

Laminate comprising a composite sheet according to claim 9 wherein a copper layer is present on at least one side of the composite sheet.

### Claim 11 (depends on 10)

Printed circuit board comprising a laminate according to claim 10, wherein electrical components are affixed to the copper layer.

### Claim 12 (depends on 9)

Solar cell provided with a composite sheet according to claim 9 as backing.

### Claim 13

(canceled)

### Claim 14 (depends on 7)

Aramid paper according to claim 7, wherein the aramid pulp is para-aramid pulp.