Loading patent…
Assignee3M Innovative Properties Company
InventorsRonald W. Ausen, William C. Unruh, Philip Miller, Jayshree Seth
Estimating the term…
A method for forming a unitary polymeric projection or fastener comprising a thin, strong flexible backing, and a multiplicity of thin spaced hook members projecting from the upper surface of the unitary backing the method generally including extruding a thermoplastic resin through a die plate which die plate is shaped to form a base layer and spaced ridges, ribs or hook elements projecting above a surface of the base layer. When the die forms, the spaced ridges or ribs the cross sectional shape of the hook members are formed by the die plate while the initial hook member thickness is formed by transversely cutting the ridges at spaced locations along their lengths to form discrete cut portions of the ridges. Subsequently longitudinal stretching of the backing layer (in the direction of the ridges on the machine direction) separates these cut portions of the ridges, which cut portion then form spaced apart hook members. The extruded hook members or cut rib hook members are then heat treated resulting in shrinkage of at least a portion of at least the hook head portion thickness by from 5 to 90 percent, preferably 30 to 90 percent.
A unitary hook fastener of a resiliently flexible, polymeric resin comprising a base film layer having generally parallel upper and lower major surfaces, with at least 50 spaced hook members per square centimeter projecting from the upper surface of said base, said hook members having a height from said upper surface of less than 1000 μm and each comprising a stem portion attached at one end to said base, and a head portion at the end of said stem portion opposite said base, at least the head portions having a thickness of from 50 to 200 μm in a first direction generally parallel to the surfaces of said backing.
A method of forming a unitary fastener comprising the steps of extruding a thermoplastic resin in a machine direction through a die plate having a continuous base portion cavity and one or more ridge cavities extending from the base portion cavity, the extrusion being sufficient to induce melt flow molecular orientation in the polymer flowing through at least the ridge cavities forming a base portion with ridges, forming projections from the thermoplastic resin extruded through the ridge cavities, and subsequently heat treating at least a portion of the solidified projections at a temperature and time sufficient to reduce the thickness of the projections.
A fastener of a resiliently flexible, polymeric resin comprising a base having generally parallel upper and lower major surfaces, with spaced upstanding projections projecting from the upper surface of said base, wherein at least a portion of the projections at an upper portion have a molecular orientation of less than 10 percent and adjacent the base film have a molecular orientation of greater than 10 percent.
A hook and loop fastener system of a unitary hook fastener and a low profile loop laminate, the unitary hook fastener comprising a base having generally parallel upper and lower major surfaces, with at least 50 spaced hook members per square centimeter projecting from the upper surface of said base, said hook members having a height from said upper surface of less than 1000 μm and each comprising a stem portion attached at one end to said base, and a head portion at the end of said stem portion opposite said base, the head portion having a thickness of from 60 to 180 μm and an arm droop of from 50 to 700 μm, the loop laminate comprising a fibrous loop web bonded to a backing layer wherein the loop web has a thickness of from 100 to 300 microns and wherein the ratio of the arm droop to the loop web thickness is 1.5 or less.
A fastener strip of a resiliently flexible, thermoplastic resin comprising a base layer having generally parallel upper and lower major surfaces, with spaced upstanding integral polymeric projections projecting from the upper surface of said base, wherein the base layer has a substantially continuous thickness across its width and wherein at least a first portion of the projections on the upper surface have a thickness or molecular orientation, less than at least another second portion of the projections on the same upper surface.
Dependencies are inferred from the claim text.