Abstract: An air-permeable packaging material which includes a non-perforated polyolefin layer having a thickness of 3 ?m to 18 ?m and constituted of at least one polymer selected from the group consisting of polypropylene and polyethylene and a net-shaped reinforcing layer; a package which includes the air-permeable packaging material, the non-perforated polyolefin layer facing outward, and which contains an oxygen scavenger, a desiccant, a deodorant, an insect repellent, or a fragrance; and a method for producing the package.

Abstract: An optical element is provided capable of reducing reflectance at whole bands of visible light. The optical element is characterized in that one of a plurality of concave sections or a plurality of convex sections are arranged on a surface at intervals smaller than a wavelength of visible light, and other not-being-arranged of the plurality of concave sections or the plurality of convex sections are each formed in each of the one arranged of the plurality of concave sections or the plurality of convex sections. A ratio of a lateral cross-sectional area of the optical element itself in a transverse plane taken along a horizontal surface may continuously increase from an upper surface toward a lower surface of the optical element according to a depth between the upper surface and the lower surface.

Abstract: A high tenacity, high initial modulus polyvinyl alcohol fiber is produced by:(1) dissolving polyvinyl alcohol with a degree of polymerization of not less than 1,500 in a solvent capable of giving a 5 wt % polyvinyl alcohol solution and the solvent is further characterized in that the nuclear magnetic resonance spectrum measured at 50.degree. C. after storage of the solution at 50.degree. C. for 96 hours following preparation thereof is substantially identical with that measured at 50.degree. C. immediately after preparation thereof, with peaks for the three kinds of hydroxyl groups of polyvinyl alcohol being clearly distinguishable in each nuclear magnetic resonance spectrum,(ii) forming filaments by spinning the spinning solution under conditions which satisfy the requirementsDs.ltoreq.5.0wherein Ds is the spinning stretch ratio defined as the ratio (V.sub.2 /V.sub.1) of the take off speed (V.sub.2) to the first take off roller speed (V.sub.

Abstract: A high tenacity, high intitial modulus polyvinyl alcohol fiber showing a high level of crystalline heat of fusion, characterized in that the fiber is made of polyvinyl alcohol having a degree of polymerization of not less than 1,500, has a tenacity of not less than 17 g/d and an initial modulus of elasticity of not less than 400 g/d and shows a crystalline heat of fusion of not less than 29 cal/g, and a method of producing said polyvinyl alcohol fiber comprising:(i) dissolving polyvinyl alcohol with a degree of polymerization of not less than 1,500 in a solvent capable of giving a 5 wt % polyvinyl alcohol solution and the solvent is further characterized in that the nuclear magnetic resonance spectrum measured at 50.degree. C. after storage of the solution at 50.degree. C. for 96 hours following preparation thereof is substantially identical with that measured at 50.degree. C.