Abstract The present invention relates to highly permeable film products and a method for the production of such products comprising continuously passing relatively unpermeable, unperforated film stock through the nip of a pair of counter-rotating rollers. One of the rollers, i.e. a perforating roller, is provided around the circumference thereof, with a plurality of relatively dull needles or brads which serve to puncture the film as it passes through the nip formed by the perforating roller and a second back-up roller. As the film is being perforated it is firmly anchored and supported in a transverse direction by both the back-up roller and a resilient elastomeric material positioned around the periphery of the perforating roller, whereby efficient and positive film perforation is achieved at high film throughput rates.
A continuous method for the production of perforated film material which comprises continuously advancing a film and (a) contacting one surface of said continually advancing film with a plurality of film penetrating members while simultaneously supporting the opposite surface of said film on a plurality of non-resilient, parallel ridges, said ridges being separated by grooves; (b) puncturing said film by pressure contact thereof with said penetrating members while simultaneously tensioning said film, in a direction transverse to the path of movement of said film, with an elastomeric material that completely surrounds, and is located immediately adjacent to, each of said film penetrating members.
Claim 2
Dependent Claim
103 words
A continuous method for the production of perforated film material which comprises continuously advancing a film and (a) contacting one surface of said continually advancing film with a plurality of film penetrating members while simultaneously supporting the opposite surface of said film on a plurality of non-resilient, parallel ridges, said ridges being separated by grooves; (b) puncturing said film by pressure contact thereof with said penetrating members while simultaneously tensioning said film, in a direction transverse to the path of movement of said film, with an elastomeric material that completely surrounds, and is located immediately adjacent to, each of said film penetrating members.
Claim 3
Dependent Claim
13 words
A method in accordance with claim 1 wherein said film material is thermoplastic.
Claim 4
Dependent Claim
13 words
A method in accordance with claim 1 wherein said film material is polyethylene.
Claim 5
Dependent Claim
18 words
A method in accordance with claim 1 wherein said film material comprises at least two layers of film.