A method of manufacturing a composite film, the method including: a coating step including coating a coating liquid containing a resin on one surface or both surfaces of a porous substrate to form a coating layer; a solidification step including solidifying the resin by bringing the coating layer into contact with a solidifying liquid to obtain a composite film including the porous substrate and a porous layer that is formed on one surface or both surfaces of the porous substrate and that includes the resin; a water washing step including washing the composite film with water; and a drying step including drying by removing water from the composite film while transporting the composite film at a transport speed of 30 m/min or more using a drying apparatus including a drying device including a contact type heating device and a hot air blowing device, wherein the composite film is brought into contact with a contact type heating device as well as exposed to hot air blown from a hot air blowing device, to remove water from the composite film being performed by bringing.

A method of manufacturing a composite film, the method including: a coating step including coating a coating liquid containing a resin on one surface or both surfaces of a porous substrate to form a coating layer; a solidification step including solidifying the resin by bringing the coating layer into contact with a solidifying liquid to obtain a composite film including the porous substrate and a porous layer that is formed on one surface or both surfaces of the porous substrate and that includes the resin; a water washing step including washing the composite film with water; and a drying step including drying by removing water from the composite film while transporting the composite film at a transport speed of 30 m/min or more using a drying apparatus including a drying device including a contact type heating device and a hot air blowing device, wherein the composite film is brought into contact with a contact type heating device as well as exposed to hot air blown from a hot air blowing device, to remove water from the composite film being performed by bringing.

[Problem] To provide a composition for an underlayer, which can form an underlayer having flattened surface.

[Means for Solution] A composition for forming an underlayer, comprising a polymer having a repeating unit containing nitrogen and a solvent. An underlayer is formed by coating this composition on a substrate, preferably baking in an inert atmosphere, and then baking in the air containing oxygen.

The present disclosure, in one aspect, relates to a polyamide solution including an aromatic polyamide and a solvent, wherein the aromatic polyamide includes at least two types of constitutional units, and a change rate of coefficient of thermal expansion (CTE) of a cast film produced by casting the polyamide solution on a glass plate and CTE of the same cast film after being subjected to a heat treatment at temperature of 200 C. to 450 C. (=CTE after heat treatment/CTE before heat treatment) is 1.3 or less.

The present disclosure, in one aspect, relates to a polyamide solution including an aromatic polyamide and a solvent, wherein the aromatic polyamide includes at least two types of constitutional units, and a change rate of coefficient of thermal expansion (CTE) of a cast film produced by casting the polyamide solution on a glass plate and CTE of the same cast film after being subjected to a heat treatment at temperature of 200 C. to 450 C. (=CTE after heat treatment/CTE before heat treatment) is 1.3 or less.

A polymer product with a metal layer coated on the surface thereof is provided. The polymer product includes a polymer substrate and a metal layer formed on at least a part of a surface of the polymer substrate. The surface of the polymer substrate covered by the metal layer is formed by a polymer composition comprising a polymer and a doped tin oxide. A doping element of the doped tin oxide comprises niobium. The doped tin oxide has a coordinate L* value of about 70 to about 100, a coordinate a value of about 5 to about 5, and a coordinate b value of about 5 to about 5 in a CIELab color space.

Provided is a doped tin oxide that can be used as a chemical plating promoter in a method for selectively metallizing a surface of an insulating substrate. Also provided are a polymer composition that includes the doped tin oxide, a polymer molded body, an ink composition, and a method for selectively metallizing a surface of an insulating substrate. The doped tin oxide has a light color, and does not interfere with the color of the substrate while presetting thereof. The doped tin oxide has a strong ability of promoting chemical plating. Using the disclosed doped tin oxide as a chemical plating promoter, a continuous metal layer can be formed with a high plating speed, together with enhanced adhesivity between the metal layer and the insulating substrate.

Provided is a doped tin oxide that can be used as a chemical plating promoter in a method for selectively metallizing a surface of an insulating substrate. Also provided are a polymer composition that includes the doped tin oxide, a polymer molded body, an ink composition, and a method for selectively metallizing a surface of an insulating substrate. The doped tin oxide has a light color, and does not interfere with the color of the substrate while presetting thereof. The doped tin oxide has a strong ability of promoting chemical plating. Using the disclosed doped tin oxide as a chemical plating promoter, a continuous metal layer can be formed with a high plating speed, together with enhanced adhesivity between the metal layer and the insulating substrate.

Colloids include a polyaramide and conductive materials, wavelength-converting materials, and/or light diffusing material. The colloid can be coated and optionally aligned on a substrate to form a film, and the film can be removed from the substrate to form a standalone film.

Colloids include a polyaramide and conductive materials, wavelength-converting materials, and/or light diffusing material. The colloid can be coated and optionally aligned on a substrate to form a film, and the film can be removed from the substrate to form a standalone film.