Abstract: Disclosed is a window film for a display device including a light transmitting substrate including a polyamide including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2, and a hard coating layer laminated on one surface of the light transmitting substrate: in Chemical Formula 1 and Chemical Formula 2, each of A1, A2, B, and D is the same as defined in the detailed description.

Abstract: A particle collection device includes a collection sheet and a frame on which the collection sheet is mounted. The collection sheet includes a base sheet, a magnetic substance, and a metal protrusion disposed on the base sheet to be adjacent to the magnetic substance.

Abstract: A poly(amide-imide) copolymer that is a reaction product of a diamine represented by Chemical Formula 1, a tetracarboxylic acid dianhydride including a compound represented by Chemical Formula 2, and a compound represented by Chemical Formula 3: wherein, in Chemical Formulae 1 to 4, R1 to R4, A, and X are the same as defined in the specification.

Abstract: A composition for preparing poly(imide-benzoxazole) copolymer is described, where the copolymer include: a tetracarboxylic acid dianhydride represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a diamine represented by Chemical Formula 3: wherein definitions of groups and variables in Chemical Formulae 1 to 3 are the same as described in the specification.

Abstract: A stacked transparent film includes a polymer film including at least one of an amide structural unit and an imide structural unit, wherein the polymer film has a refractive index of about 1.65 to about 1.75 at a 550 nanometer wavelength and an elastic modulus of greater than or equal to about 5.5 gigapascals; and at least one of a first coating layer on a first side of the polymer film and a second coating layer on a side opposite the first side of the polymer film.

Abstract: Disclosed are a laminated film including a light transmitting substrate; a hard coating layer; and an optical enhancement layer disposed between the light transmitting substrate and the hard coating layer or at a position facing the hard coating layer with the light transmitting substrate therebetween, wherein the light transmitting substrate includes a polyimide, a poly(amide-imide) copolymer, or a combination thereof, and the optical enhancement layer includes a copolymer comprising a polyimide, and a display device including the laminated film.

Abstract: A flexible plastic substrate includes a film including a poly(amide-imide) copolymer; and a hard coating layer disposed on a first surface of the film, wherein the hard coating layer includes a crosslinked siloxane copolymer, and wherein the flexible plastic substrate has pencil hardness of greater than or equal to 2H under a vertical load of 1 kilogram according to ASTM D3363, a total light transmittance of greater than or equal to about 89% in a wavelength region of 350 nanometers to 750 nanometers.

Abstract: A polyimide that is a reaction product of a diamine represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a tetracarboxylic dianhydride represented by Chemical Formula 3: wherein, in Chemical Formulae 1 to 3, L1, L2, Ra to Rf, m, R2, R10, R12, R13, n7, and n8 are the same as defined in the specification.

Abstract: A laminated film including a first film; and a second film disposed on the first film, wherein a tensile modulus of the second film is greater than or equal to a tensile modulus of the first film, and a transmittance of the first film is greater than or equal to a transmittance of the second film, provided that at least one of the tensile modulus of the first film and the tensile modulus of the second film are not equal or the transmittance of the first film and the transmittance of the second film are not equal.

Abstract: A film comprising a polyimide or poly(imide-amide) copolymer, wherein the film has an amplitude of a surface roughness curve of less than or equal to 270 nanometers.

Abstract: A poly(amide-imide) copolymer including a structural unit represented by Chemical Formula 1; a structural unit represented by Chemical Formula 2, and/or an amic acid precursor structural unit which forms the structural unit represented by Chemical Formula 2 through imidization; and a structural unit represented by Chemical Formula 3, and/or an amic acid precursor structural unit which forms the structural unit represented by Chemical Formula 3 through imidization, wherein the poly(amide-imide) copolymer has a modulus of greater than or equal to about 5.5 giga Pascals after being cured, a yellowness index YI of less than or equal to about 3.5, and an increase in yellowness index ?YI of less than or equal to about 0.7 after being exposed to ultraviolet light for 72 hours: wherein in Chemical Formulae 1 to 3, groups and variables are the same as described in the specification.

Abstract: A flexible plastic substrate includes a film including a poly(amide-imide) copolymer; and a hard coating layer disposed on a first surface of the film, wherein the hard coating layer includes a crosslinked siloxane copolymer, and wherein the flexible plastic substrate has pencil hardness of greater than or equal to 2H under a vertical load of 1 kilogram according to ASTM D3363, a total light transmittance of greater than or equal to about 89% in a wavelength region of 350 nanometers to 750 nanometers.

Abstract: A stacked transparent film includes a polymer film including at least one of an amide structural unit and an imide structural unit, wherein the polymer film has a refractive index of about 1.65 to about 1.75 at a 550 nanometer wavelength and an elastic modulus of greater than or equal to about 5.5 gigapascals; and at least one of a first coating layer on a first side of the polymer film and a second coating layer on a side opposite the first side of the polymer film.

Abstract: A window for a display device including a plastic substrate having yield strain of greater than or equal to about 0.8% at about 85 degrees Celsius and 85% relative humidity and a hard coating layer disposed on at least one side of the plastic substrate.

Abstract: A poly(amide-imide) copolymer film having a compressive modulus of greater than or equal to about 1.8 gigaPascals and a yellowness index of less than or equal to about 3, when measured according to an ASTM E313 standard.

Abstract: A slot die includes a material distribution chamber configured to distribute a casting solution supplied to the material distribution chamber, and a lip in which a slot including an expansion portion is defined and through which the casting solution distributed in the material distribution chamber is discharged, where a width of the expansion portion taken in a first direction is expanded from one side of the expansion portion to a lip end facing the one side and the one side of the expansion portion is apart from the lip end by a predetermined length taken along a second direction which is perpendicular to the first direction and substantially parallel to a flow direction of the casting solution.

Abstract: A composition for preparing poly(imide-benzoxazole) copolymer is described, where the copolymer include: a tetracarboxylic acid dianhydride represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a diamine represented by Chemical Formula 3: wherein definitions of groups and variables in Chemical Formulae 1 to 3 are the same as described in the specification.

Abstract: A poly(amide-imide) copolymer including a structural unit represented by Chemical Formula 1; a structural unit represented by Chemical Formula 2, and/or an amic acid precursor structural unit which forms the structural unit represented by Chemical Formula 2 through imidization; and a structural unit represented by Chemical Formula 3, and/or an amic acid precursor structural unit which forms the structural unit represented by Chemical Formula 3 through imidization, wherein the poly(amide-imide) copolymer has a modulus of greater than or equal to about 5.5 giga Pascals after being cured, a yellowness index YI of less than or equal to about 3.5, and an increase in yellowness index ?YI of less than or equal to about 0.7 after being exposed to ultraviolet light for 72 hours: wherein in Chemical Formulae 1 to 3, groups and variables are the same as described in the specification.

Abstract: A window for a display device including a plastic substrate including a poly(imide-amide) copolymer and a hard-coating layer disposed on at least one side of the plastic substrate, wherein the plastic substrate has pencil scratch hardness of greater than or equal to about 3H under a vertical load of about 1 kilogram according to ASTM D3363 and a yellow index (YI) of less than or equal to 3 according to ASTM E313.

Abstract: A window for a display device including a plastic substrate having yield strain of greater than or equal to about 0.8% at about 85 degrees Celsius and 85% relative humidity and a hard coating layer disposed on at least one side of the plastic substrate.