# US 2021/0278580 A1 · Method for producing a polarizing plate

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- Number: US 2021/0278580 A1
- Document ID: US20210278580A1
- Status: Published application
- Kind: A1
- Application number: 17/329,147
- Filed: 2021-05-25
- Published: 2021-09-09
- Earliest claimed: 2017-07-25
- Assignees: Zeon Corporation
- Applicants: Zeon Corporation
- Inventors: Hiromu MASHIMA; Takamichi INOMATA
- Web page: https://patentgrep.com/patent/US20210278580A1

## CPC

- G02B 5/305: {including organic materials, e.g. polymeric layers}
- B29D 11/00644: {polarizing}
- G02B 1/14: Protective coatings, e.g. hard coatings
- G02F 1/133528: {Polarisers}
- H10K 59/8791: {Arrangements for improving contrast, e.g. preventing reflection of ambient light}
- G09F 9/35: being liquid crystals (G09F9/302 takes precedence; liquid crystal materials C09K19/00; {liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13})
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS

## Abstract

A method for producing a polarizing plate including a polarizer and a substrate film is provided. The method comprises: stretching a primary film to obtain a polarizer material film; providing an unstretched substrate film on the polarizer material film to obtain a layered body; and stretching the layered body to obtain the polarizing plate. The polarizer includes a dichroic material and has a thickness T of 20 μm or less. A phase difference Re in an in-plane direction of the substrate film in the polarizing plate is 20 nm or less.

## Claims

### Claim 1

A method for producing a polarizing plate including a polarizer and a substrate film, the method comprising:
stretching a primary film to obtain a polarizer material film,
providing an unstretched substrate film on the polarizer material film to obtain a layered body, and
stretching the layered body to obtain the polarizing plate, wherein
the polarizer includes a dichroic material and has a thickness T of 20 μm or less, and
a phase difference Re in an in-plane direction of the substrate film in the polarizing plate is 20 nm or less.

### Claim 2 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein the layered body further includes an adhesive layer that is provided between the polarizer material film and the unstretched substrate film.

### Claim 3 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein the substrate film is a film layer formed of at least one type selected from a cycloolefin resin, an amorphous polyester resin, a polyolefin resin, and an acrylic resin.

### Claim 4 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein
the substrate film is a film formed of a cycloolefin resin,
the cycloolefin resin contains a cycloolefin-based polymer, and
the cycloolefin-based polymer is formed of at least one type selected from a hydrogenated product of a ring opening polymer of a norbornene-based monomer, an addition copolymer of a norbornene-based monomer and an α-olefin, and a hydrogenated product thereof.

### Claim 5 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein
the substrate film is a film formed of a cycloolefin resin,
the cycloolefin resin contains a cycloolefin-based polymer, and
the cycloolefin-based polymer is composed of a hydrogenated product of a block copolymer obtained by hydrogenating a block copolymer [D] composed of:
a polymer block [A] containing a repeating unit [I] derived from an aromatic vinyl compound as a main component; and
a polymer block [B] containing the repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a chain conjugated diene compound as a main component or a polymer block [C] containing the repeating unit [II] derived from a chain conjugated diene compound as a main component.

### Claim 6 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein the substrate film contains a plasticizer, a softener or both thereof.

### Claim 7 (depends on 6)

The method for producing a polarizing plate according to claim 6, wherein the plasticizer, softener or both thereof is one or more types selected from an ester-based plasticizer and an aliphatic hydrocarbon polymer.

### Claim 8 (depends on 1)

The method for producing a polarizing plate according to claim 1, comprising a protective film or a tackiness agent layer on one surface of the polarizer.

### Claim 9 (depends on 8)

The method for producing a polarizing plate according to claim 8, wherein the protective film is formed of a cycloolefin resin, an acrylic resin, a polyethylene terephthalate resin, or a triacetyl cellulose resin.

### Claim 10 (depends on 1)

The method for producing a polarizing plate according to claim 1, wherein a stretching temperature of the layered body in the stretching step is 65° C. or lower.