Abstract: The present invention relates to a polyimide film showing a low stress change rate on a silicon wafer. The present invention can minimize cracks which are formed due to the stress change of polyimide, in a process for depositing an inorganic film on a polyimide substrate at a high temperature, and thus can reduce electrical property degradation such as a recoverable residual image and decrease in current of a flexible display.

Abstract: The present invention provides a siloxane compound having a novel structure, the compound not being reactive with a polyamic acid which is a polyimide precursor. In addition, provided is a polyimide precursor composition having improved storage stability by adding the siloxane compound as an enhancer for adhesion between a polyimide and a substrate made of an inorganic material. According to the present invention, provided is a multifunctional polyimide film having improved adhesiveness with a substrate made of an inorganic material while having improved optically isotropic characteristics and reduced residual stress characteristics with respect to a substrate.

Abstract: The present invention provides a novel polyimide resin adhesion enhancer having a fluorene framework, wherein a polyimide film produced using same exhibits conventional properties such as heat resistance and mechanical properties, and maintains adhesion with a carrier substrate while not being affected with respect to retardation even during a high-temperature process.

Abstract: The present invention provides a polyimide precursor solution which can enhance the uniformity of a polyimide film and also improve the efficiency of processes by improving liquid curl in a coating process of the polyimide precursor solution. In addition, since polyimide according to the present invention has excellent transparency, heat resistance, mechanical strength and flexibility by comprising a specific structure, the polyimide may be used in various fields, such as substrates for devices, cover substrates for displays, optical films, integrated circuit (IC) packages, adhesive films, flexible printed circuits (FPCs), tapes, touch panels, protective films for optical discs, etc.

Abstract: A polyimide copolymer according to the present invention has a particular structure in which siloxane structures are distributed in a nanosize in a polymer and thus enables excellent transparency, heat resistance, mechanical strength and flexibility and effective reduction of residual stress, and thus can be used in various fields such as a substrate for a device, a cover substrate for a display, an optical film, an integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), tape, a touch panel and a protective film for an optical disk.

Abstract: The present invention relates to the production of a polyimide precursor, whereby, by using an amide-based organic solvent having a positive-number partition coefficient (Log P) and a density of at most 1 g/cm3, an interaction between the organic solvent and polyamic acid, which is a polyimide precursor, may be mitigated, thereby enabling the decrease of the viscosity of a polyimide precursor solution, and thus enabling a polyimide precursor solution having high solid content and low viscosity to be obtained.

Abstract: According to the present invention, damage such as film tearing during a rolling process can be reduced by using, as a substrate for a flexible display, a polyimide film having the thickness of 5-10 ?m, modulus of 3-8 GPa, the absolute value of out-of-plane retardation (Rth) of 200-600 nm, and a strain, at a tensile force of 100 MPa, of 10% or less. In addition, since the polyimide film has low residual stress with respect to inorganic substrates, the occurrence of defects during a TFT process is reduced. As a result, processing reliability for a flexible display can be improved. In addition, the saturated static electricity half-life of the polyimide film is controlled to be 250 seconds or more so as to minimize the voltage loss ratio of saturated static electricity and reduce the current drop during a TFT operation, and, as a result, enables a display having improved luminosity to be provided.

Abstract: A polyimide precursor composition according to the present invention enables alleviation of thermal expansion-contraction properties of a polyimide film resultingly prepared, by means of using siloxane-based diamine having a particular structure and a solvent having a positive partition coefficient. And the present invention enables excellent transparency, heat resistance, mechanical strength and flexibility and effective reduction of residual stress, and thus can be used in various fields such as a substrate for a device, a cover substrate for a display, an optical film, an integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), tape, a touch panel and a protective film for an optical disk.

Abstract: The present invention provides a novel diamine compound capable of producing a polymer which exhibits greatly enhanced mechanical properties and heat resistance while maintaining transparency. A film including a polymer produced using the diamine compound has excellent transparency, heat resistance, mechanical strength and flexibility, and thus can be used in various fields, such as in a device substrate, a display cover substrate, an optical film, an Integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), a tape, a touch panel and an optical disc protection film, and the like.

Abstract: The present invention provides a polyimide film forming composition which comprises a polyamic acid or a polyimide in an oligomer form or in a low-molecular weight form, the polyamic acid or the polyimide being prepared from a diamine containing an intramolecular imide group, and thus can provide a polyimide film having improved heat resistance while retaining optical properties thereof. In addition, the polyimide film according to the present invention can reduce not only a laser energy density (E/D) required in the laser exfoliation process but also remarkably decrease an amount of ash generated by an exfoliation process, thereby further improving the reliability of a device in a display manufacturing process.

Abstract: The present invention relates to a laminated film roll body, around which a laminated film is wound, the laminated film including: a first polyimide film; and a second polyimide film laminated on the first polyimide film and made of a fluorine-based, siloxane-based, or amine-based polyamic acid, wherein the second polyimide film has a glass transition temperature of 350° C. or higher when measured by a temperature elevation rate of 20° C./min. The laminated film roll body can be used in a continuous manufacturing process of a flexible device to improve process yield and efficiency.

Abstract: A polyimide copolymer according to the present invention has a particular structure in which siloxane structures are distributed in a nanosize in a polymer and thus enables excellent transparency, heat resistance, mechanical strength and flexibility and effective reduction of residual stress, and thus can be used in various fields such as a substrate for a device, a cover substrate for a display, an optical film, an integrated circuit (IC) package, an adhesive film, a multi-layer flexible printed circuit (FPC), tape, a touch panel and a protective film for an optical disk.

Abstract: The laminate for manufacturing a flexible substrate according to the present invention is formed by using a polyimide having a high absorbance to a UV laser in an organic sacrificial layer for delaminating a flexible substrate from a carrier substrate. Therefore, it is possible that the laser energy density required in the delaminating process using laser irradiation is reduced and the amount of as generated by the delaminating process is remarkably reduced so that the efficiency of the process, the permeability of the flexible substrate is improved and the reliability of the device is improved.

Abstract: According to the present invention, damage such as film tearing during a rolling process can be reduced by using, as a substrate for a flexible display, a polyimide film having the thickness of 5-10 ?m, modulus of 3-8 GPa, the absolute value of out-of-plane retardation (Rth) of 200-600 nm, and a strain, at a tensile force of 100 MPa, of 10% or less. In addition, since the polyimide film has low residual stress with respect to inorganic substrates, the occurrence of defects during a TFT process is reduced. As a result, processing reliability for a flexible display can be improved. In addition, the saturated static electricity half-life of the polyimide film is controlled to be 250 seconds or more so as to minimize the voltage loss ratio of saturated static electricity and reduce the current drop during a TFT operation, and, as a result, enables a display having improved luminosity to be provided.

Abstract: The present invention provides a siloxane compound having a novel structure, the compound not being reactive with a polyamic acid which is a polyimide precursor. In addition, provided is a polyimide precursor composition having improved storage stability by adding the siloxane compound as an enhancer for adhesion between a polyimide and a substrate made of an inorganic material. According to the present invention, provided is a multifunctional polyimide film having improved adhesiveness with a substrate made of an inorganic material while having improved optically isotropic characteristics and reduced residual stress characteristics with respect to a substrate.

Abstract: The present invention provides a polyimide precursor solution which can enhance the uniformity of a polyimide film and also improve the efficiency of processes by improving liquid curl in a coating process of the polyimide precursor solution. In addition, since polyimide according to the present invention has excellent transparency, heat resistance, mechanical strength and flexibility by comprising a specific structure, the polyimide may be used in various fields, such as substrates for devices, cover substrates for displays, optical films, integrated circuit (IC) packages, adhesive films, flexible printed circuits (FPCs), tapes, touch panels, protective films for optical discs, etc.

Abstract: The present invention provides a polyimide film which, by having a fluorine structure adopted into a rigid polyamide chain structure, exhibits not only superb heat resistance but also enhanced optical properties. Additionally, the polyimide according to the present invention, by having the particular structure, exhibits excellent transparency, heat-resistance, mechanical strength and flexibility, and thus can be utilized in a variety of functions such as an element substrate, display cover substrate, optical film, integrated circuit (IC) package, adhesive film, multi-layered flexible printed circuit (FPC), tape, touch panel, and protective film for optical disks.

Abstract: The present invention relates to a polyimide film showing a low stress change rate on a silicon wafer. The present invention can minimize cracks which are formed due to the stress change of polyimide, in a process for depositing an inorganic film on a polyimide substrate at a high temperature, and thus can reduce electrical property degradation such as a recoverable residual image and decrease in current of a flexible display.

Abstract: The present invention relates to a polyimide-based solution that can be used to produce an isotropic transparent polyimide-based film with high heat resistance and excellent mechanical properties as well as high transmittance. A coating of the polyimide-based solution on a substrate has a haze of 1% or less after storage at a temperature of 30° C. and a humidity of 70% for 30 minutes.

Abstract: The present invention relates to the production of a polyimide precursor, whereby, by using an amide-based organic solvent having a positive-number partition coefficient (Log P) and a density of at most 1 g/cm3, an interaction between the organic solvent and polyamic acid, which is a polyimide precursor, may be mitigated, thereby enabling the decrease of the viscosity of a polyimide precursor solution, and thus enabling a polyimide precursor solution having high solid content and low viscosity to be obtained.