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AssigneeMinnesota Mining and Manufacturing Company
InventorsRalph H. Bland, James M. Jonza, James D. Smith, Richard C. Allen, Jeffrey F. Bradley, Kenneth B. Smith, Bruce D. Stambaugh
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A tear resistant film comprises more than five layers situated one on the other in a parallel array. The layers are individually selected from a stiff polyester or copolyester, a ductile polymeric material, and optionally, an intermediate material. The stiff polyester or copolyester is oriented in at least one direction. Tear resistance may be measured in a Graves area test and reflects the ability of the film to absorb energy. The films of the invention are useful in many articles including security control laminates for glazing members.
A security control laminate comprising a first tear resistant film having a first face and a second face opposite the first face and a first layer of adhesive on the first face of the tear resistant film for bonding the security control laminate to a surface, the first tear resistant film comprising a total of more than five stiff and ductile layers situated one on the other in a parallel array, the layers occurring essentially randomly in the array, wherein (a) at least two of the layers are a stiff polyester or copolyester that has a tensile modulus greater than 200 kpsi, the layers of stiff polyester or copolyester having an average nominal thickness greater than about 1 .mu.m, and (b) at least two other layers are a ductile polymeric material that has been oriented in at least one direction, has a tensile modulus less than 200 kpsi, and has a tensile elongation greater than 50%.
A security control laminate comprising a first tear resistant film having a first face and a second face opposite the first face and a first layer of adhesive on the first face of the tear resistant film for bonding the security control laminate to a surface, the first tear resistant film comprising a total of more than five stiff and ductile layers situated one on the other in a parallel array, the layers occurring essentially randomly in the array, wherein (a) at least two of the layers are a stiff polyester or copolyester that has a tensile modulus greater than 200 kpsi, the layers of stiff polyester or copolyester having an average nominal thickness of about 1 to 15 .mu.m, and (b) at least two other layers are a ductile polymeric material that has a tensile modulus less than 200 kpsi and a tensile elongation greater than 50%, wherein the ductile polymeric material is selected from the group consisting of ethylene copolymers, polyesters, copolyesters, polyolefins, and polyamides.
A security control laminate comprising a tear resistant film having a first face and a second face opposite the first face and a first layer of adhesive on the first face of the tear resistant film for bonding the security control laminate to a surface, the tear resistant film comprising a total of more than five stiff and ductile layers situated one on the other in a parallel array, the layers occurring essentially randomly in the array, wherein (a) at least two of the layers are a stiff polyester or copolyester that has a tensile modulus greater than 200 kpsi, the layers of stiff polyester or copolyester having an average nominal thickness of about 1 to 15 .mu.m, and (b) at least two other layers are a ductile polymeric material that has a tensile modulus less than 200 kpsi and a tensile elongation greater than 50%, the layers of ductile polymeric material having an average nominal thickness of less than 3 .mu.m.
A security control laminate comprising:
Dependencies are inferred from the claim text.