Zipper tape, packing bag with zipper tape and apparatus for producing packing bag with zipper tape

A zipper tape, comprising:

• a male member including a first engagement portion and a first belt-like base continued to the first engagement portion and a female member including a second engagement portion and a second belt-like base continued to the second engagement portion, the first and the second engagement portions mating in a pair, wherein
• one of the first and the second belt-like bases is widened from the mating first and second engagement portions to a crosswise end of the one of the first and the second belt-like bases relative to the other of the first and the second belt-like bases in order to define a seal base,
• a bond layer and an easy-peel layer bonded to the seal base via the bond layer are layered on a first surface of the seal base in side of the mating first and second engagement portions,
• the seal base is formed of polypropylene,
• the bond layer is formed of a mixture of polypropylene and low density polyethylene,
• the easy-peel layer is formed of a mixture of low density polyethylene and polypropylene, and
• a ratio of polypropylene in the easy-peel layer is less than a ratio of polypropylene in the bond layer.

A zipper tape, comprising:

• a male member including a first engagement portion and a first belt-like base continued to the first engagement portion and a female member including a second engagement portion and a second belt-like base continued to the second engagement portion, the first and the second engagement portions mating in a pair, wherein
• one of the first and the second belt-like bases is widened from the mating first and second engagement portions to a crosswise end of the one of the first and the second belt-like bases relative to the other of the first and the second belt-like bases in order to define a seal base,
• a bond layer, an easy-peel layer bonded to the seal base via the bond layer, and a seal layer provided on a first surface of the easy-peel layer are layered on a first surface of the seal base in side of the mating first and second engagement portions,
• the seal base is formed of polypropylene,
• the bond layer is formed of a mixture of polypropylene and low density polyethylene,
• the easy-peel layer is formed of low density polyethylene, and the seal layer is formed of polypropylene.

A zipper tape, comprising:

• a male member including a first engagement portion and a first belt-like base continued to the first engagement portion and a female member including a second engagement portion and a second belt-like base continued to the second engagement portion, the first and the second engagement portions mating in a pair, wherein
• one of the first and the second belt-like bases is widened from the mating first and second engagement portions to a crosswise end of the one of the first and the second belt-like bases relative to the other of the first and the second belt-like bases in order to define a seal base,
• an easy-peel layer and a bond layer provided on a surface of the easy-peel layer are layered on a surface of the seal base in side of the mating first and second engagement portion,
• the seal base is formed of polypropylene,
• the bond layer is formed of a mixture of polypropylene and low density polyethylene,
• the easy-peel layer is formed of a mixture of low density polyethylene and polypropylene, and
• a ratio of polypropylene in the easy-peel layer is less than a ratio of polypropylene in the bond layer.