JP-7856929-B2 - Resin film for optical films and method for manufacturing a resin film for optical films

Inventors

• 森 一紘
• 西川 理穂

Assignees

• 新日本理化株式会社

Dates

Publication Date

20260512

Application Date

20240731

Priority Date

20230810

Claims (7)

1. (Meth)acrylic acid ester polymers, Carboxylic acid amide compounds having an aromatic ring, It contains, The carboxylic acid amide compound is contained in an amount of 1,000 ppm to 11,000 ppm relative to the (meth)acrylic acid ester polymer. The carboxylic acid amide compound is contained in crystalline form, and the crystal exhibits negative birefringence. Resin film for optical films.
2. The carboxylic acid amide compound is contained in an amount of 2,000 ppm to 10,000 ppm relative to the (meth)acrylic acid ester polymer. A resin film for optical films according to claim 1.
3. The haze value of a 0.1 mm thick film is 7.0 or less. A resin film for optical films according to claim 1 or claim 2.
4. The carboxylic acid amide compound is It is a carboxylic acid amide compound having an aromatic ring and an aliphatic ring. A resin film for optical films according to claim 1 or claim 2.
5. The carboxylic acid amide compound is It is a carboxylic acid amide compound having a structure in which a polycarboxylic acid having either a benzene ring or a naphthalene ring is condensed with an amine having an aliphatic ring. A resin film for optical films according to claim 1 or claim 2.
6. A (meth)acrylic acid ester polymer and a carboxylic acid amide compound having an aromatic ring in a proportion of 1,000 ppm to 11,000 ppm relative to the (meth)acrylic acid ester polymer are mixed. A step of heating the polymer to a temperature above the softening temperature of the (meth)acrylic acid ester polymer and below the decomposition temperature of the (meth)acrylic acid ester polymer, and then molding it. The process includes forming a film by cooling, A method for manufacturing resin films for optical films.
7. The carboxylic acid amide compound is It is a carboxylic acid amide compound having a structure in which a polycarboxylic acid having either a benzene ring or a naphthalene ring is condensed with an amine having an aliphatic ring. A method for manufacturing a resin film for optical films according to claim 6.

Description

The present invention relates to a resin film for optical films and a method for manufacturing a resin film for optical films. This application claims priority under Japanese Patent Application No. 2023-130926, filed on 10 August 2023, and incorporates all the provisions of the said Japanese Patent Application. Acrylic acid-based resin films with distinctive optical properties are known. For example, Patent Document 1 discloses a resin film for optical films comprising a methacrylic acid ester polymer and a diacetal compound having a specific structure. The resin film disclosed in Patent Document 1 is characterized by not exhibiting dispersion defects and having low birefringence. Patent Document 2 discloses a substrate for a surface protection film to protect the surface of an image display device. The substrate for the surface protection film disclosed in Patent Document 2 is characterized by having a specific range of phase difference characteristics. The specific composition of this film substrate is disclosed to include at least one resin selected from polycarbonate, polyester, cycloolefin resin, acrylic resin, and cellulose resin. Furthermore, it is disclosed that the film substrate may include a resin having an alicyclic structure or an aromatic ring structure exhibiting negative intrinsic birefringence. Japanese Patent Publication No. 2010-254370WO2020/054135 publication Figure 1 is a polarized light microscope image showing the crystals of the optical modifier contained in the resin film according to this disclosure. [Summary of Embodiments] First, embodiments of the resin film for optical films and the method for manufacturing the same according to this disclosure will be listed and described. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or greater, B or less". The resin film for optical films according to this disclosure contains a (meth)acrylic acid ester polymer and a carboxylic acid amide compound having an aromatic ring. The carboxylic acid amide compound is contained in an amount of 1,000 ppm to 11,000 ppm relative to the (meth)acrylic acid ester polymer. The carboxylic acid amide compound is contained as crystals, and these crystals exhibit negative birefringence. Conventionally, many proposals have been made regarding resin films with adjusted optical properties. For example, Patent Document 1 proposes a resin film for optical films that contains a specific acetal compound and exhibits low birefringence. Furthermore, Patent Document 2 proposes a film in which a chemical structure thought to exhibit negative birefringence is incorporated into the side chains of the resin constituting the film. The resin film for optical films according to this disclosure contains a carboxylic acid amide compound having a specific structure in a (meth)acrylic acid ester polymer. The carboxylic acid amide compound exists as crystals in the film, and these crystals exhibit negative birefringence. The resin film for optical films according to this disclosure can be constructed by incorporating an optical modifier in any concentration within a wide range of 1,000 ppm to 11,000 ppm relative to the base resin constituting the film, and this film exhibits remarkable optical properties. At the same time, the resin film for optical films according to this disclosure is a film with sufficient transparency and possesses characteristic functions as a resin film for optical films. In the aforementioned resin film for optical films, the carboxylic acid amide compound may be contained in an amount of 2,000 ppm to 10,000 ppm relative to the (meth)acrylic acid ester polymer. When the content of the carboxylic acid amide compound is within this range, the effects of the resin film for optical films according to this disclosure become clearer. In the aforementioned resin film for optical films, the haze value of a film with a thickness of 0.1 mm may be 7.0 or less. According to the resin film for optical films of this disclosure, even when the film is thick at 0.1 mm and has sufficient strength, transparency is maintained, and the characteristic of exhibiting negative birefringence due to crystal precipitation within the film is achieved. In the aforementioned resin film for optical films, the carboxylic acid amide compound may be a carboxylic acid amide compound having an aromatic ring and an aliphatic ring. Compounds having this structure exhibit negative birefringence and precipitate as crystals in films produced by general methods. In the aforementioned resin film for optical films, the carboxylic acid amide compound may be a carboxylic acid amide compound having a structure in which a polycarboxylic acid having either a benzene ring or a naphthalene ring is condensed with an amide compound having an aliphatic ring. It has been found in this disclosure that a carboxylic acid amide compound having such a structure exhibits negative birefringence and functions as an opti