An adhesive sheet of an embodiment of the present disclosure is an adhesive sheet including: a rigid resin film having a thickness of 80 micrometers to 500 micrometers, and a first pressure sensitive adhesive layer being disposed on or above a surface of the rigid resin film, wherein the first pressure sensitive adhesive layer includes elastic resin microspheres having a volume average particle diameter of 110 micrometers or greater and a tacky binder, and the first pressure sensitive adhesive layer has an uneven surface due to the presence of the microspheres.

A hot melt adhesive composition may include a biobased ethylene vinyl acetate (EVA) copolymer comprising a biobased carbon content as determined by ASTM D6866-18 Method B of 5% to 95%. A hot melt adhesive composition may also include a biobased ethylene vinyl acetate (EVA) copolymer at an amount ranging from 10 to 80 wt % of the hot melt adhesive composition, wherein the biobased EVA comprises a melt index (I.sub.2) as determined by ASTM D1238 in the range of 1.5 to 50 g/10 min measured with a load of 2.16 kg at 190° C.; and a tackfier at an amount ranging from 30 to 70 wt % of the hot melt adhesive composition.

An elastic tape or film of a aqueous polyurethane dispersion with solid low melt powder which can be applied to a fabric via transfer printing as well as methods for production of the elastic tape or film, articles of manufacture comprising the elastic tape or film and methods for production of the elastic tape or film are provided.

An adhesive film includes a base material layer, an adhesive resin layer (A) provided on a first surface side of the base material layer, and an adhesive resin layer (B) provided on a second surface side of the base material layer and of which an adhesive force is reduced by an external stimulus. When a mass of the adhesive film after heating and drying at 130° C. for 30 minutes is defined as W1 and the mass of the adhesive film after the heated and dried adhesive film is left for 24 hours at 25° C. under an atmosphere of 50% RH to absorb water is defined as W2, an average water absorption rate indicated by 100×(W2−W1)/W1 is 0.90% by mass or less.

Provided are a polyester film, a laminated film, and the like for protecting an organic EL module of a foldable display each of which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for protecting an organic EL module of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm.sup.3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Provided is a laminated film for a foldable display, the laminated film being free of occurrence of a fold mark or a crack at a folding portion thereof, in order to provide, for example, a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The laminated film for a foldable display includes: a polyester film having a thickness of from 10 μm to 100 μm; and an adhesive layer formed on at least one surface of the polyester film, wherein the polyester film satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm.sup.3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

A wafer processing method includes a polyester sheet providing step of positioning a wafer in an inside opening of a ring frame and providing a polyester sheet on a back side or a front side of the wafer and on a back side of the ring frame, a uniting step of heating the polyester sheet as applying a pressure to the polyester sheet to thereby unite the wafer and the ring frame through the polyester sheet by thermocompression bonding, a dividing step of applying a laser beam to the wafer to form modified layers in the wafer, thereby dividing the wafer into individual device chips, and a pickup step of cooling the polyester sheet in each of the plurality of separate regions corresponding to each device chip, pushing up each device chip through the polyester sheet, then picking up each device chip from the polyester sheet.

Disclosed is a PET (polyethylene terephthalate) film capable of being laminated by heat sealing on a metal. The PET film is a coextruded PET film including an intermediate layer, and a surface layer and a heat seal layer bound to respective sides of the intermediate layer, the heat seal layer including 100 parts by weight of a PET resin modified simultaneously with 1,4-cyclohexane dimethanol, 1,3-propanediol, and 1,4-butanediol, and 10 to 50 parts by weight of a PET resin modified with isophthalic acid.

A wafer processing method includes a polyester sheet providing step of positioning a wafer in an inside opening of a ring frame and providing a polyester sheet on a back side or a front side of the wafer and on a back side of the ring frame, a uniting step of heating the polyester sheet as applying a pressure to the polyester sheet to thereby unite the wafer and the ring frame through the polyester sheet by thermocompression bonding, a dividing step of applying a laser beam to the wafer to form shield tunnels in the wafer, thereby dividing the wafer into individual device chips, and a pickup step of blowing air to each device chip from the polyester sheet side to push up each device chip through the polyester sheet and picking up each device chip from the polyester sheet.

A wafer processing method includes a polyester sheet providing step of positioning a wafer in an inside opening of a ring frame and providing a polyester sheet on a back side or a front side of the wafer and on a back side of the ring frame, a uniting step of heating the polyester sheet as applying a pressure to the polyester sheet to thereby unite the wafer and the ring frame through the polyester sheet by thermocompression bonding, a dividing step of applying a laser beam to the wafer to form shield tunnels in the wafer, thereby dividing the wafer into individual device chips, and a pickup step of cooling the polyester sheet, pushing up each device chip through the polyester sheet, and picking up each device chip from the polyester sheet.