Patent ID: 8501072

Claim:
A method of manufacturing a dispensing valve for dispensing flowable material comprising: injecting hot, flowable polyolefin material into a mould cavity, which mould cavity is defined by a first mould member on one side and a second mould member on the other side, the second mould member including at least one movable rupture member, the second mould member creating one or more first elongate recesses in a surface of the dispensing valve, thereby creating one or more first lines of reduced thickness for subsequently forming a valve member having one or more valve flaps connected via an integral hinge, permitting the polyolefin material to cool to a temperature of between 40° C. and 70° C. and thus solidify to provide a the valve member which is still warm and soft, moving the second mould member relative to the first mould member to create a gap, advancing the at least one rupture member against the valve member while the valve member is at said temperature to initially cause stretching that reduces the thickness at the first lines of reduced thickness, then rupturing the stretched and reduced thickness recesses with a respective rupture member to provide one or more apertures, each of which is occupied by a respective one of said valve flaps, which flap is connected with the valve member by said integral hinge, the valve flap having first margins and the one or more apertures having second margins, the first and second margins overlapping each other, the first and second margins having varying thickness increasing from a minimum at the free edge of the margins to a maximum at a line spaced from the free edge of the margins, and ejecting the valve member.