Patent ID: 8435622

Claim:
A packaging film, comprising a main film made of a stretchable polymer film material and having a main direction; and a multiplicity of holes on the main film; wherein the holes on the main film are arranged in at least three substantially parallel columns along the main direction; the columns of holes are staggered with respect to the main direction such that a center of one hole in one column is on a different line transverse to the main direction than the centers of adjacent holes in the immediately adjacent columns; the main film is made of structural polyethylene films material or copolymers thereof; a ratio of aeration percentage over final weight of the packaging film is greater than or equal to 14 meters per gram; the aeration percentage is calculated for a predetermined length of the packaging film as the total area covered by the holes over the total area of the packaging film including the area of the holes, when the packaging film is stretched along a main direction to an elongation equal to the elongation at the Natural Draw Ratio point (NDR point), wherein the predetermined length is greater than or equal to about 0.3 meters; the final weight is the weight of the packaging film per said film meter measured in grams per meter, when the packaging film is stretched along a main direction at an elongation equal to the elongation at the Natural Draw Ratio point (NDR point); an initial width of the packaging film is reducible by less than 15% between a condition before any stretching of the packaging film and a condition when the packaging film is stretched along a main direction at an elongation equal to the elongation at the Natural Draw Ratio point (NDR point); a ratio of an absolute value of the difference of a predetermined target holding force of the packaging film minus a holding force divided by the predetermined target holding force is less than or equal to 5%, wherein the predetermined target holding force is greater than or equal to 70 Newtons and less than or equal to 380 Newtons, and wherein the holding force of the packaging film is determined as the tensile force at the Natural Draw Ratio point (NDR point); and a ratio of an elongation at break of the packaging film measured along a transverse direction to the main direction over the elongation at the Natural Draw Ratio point (NDR point) is greater than or equal to 50%.