Buttress-type thread

British Standard 5789 1979 applies to plastic containers and closures requiring a buttress-type thread. 

Moulded-in internal or external threads can be used with PP. The design of threads is important to avoid the possibility of thread jumping. Thread jumping may occur if high torque is applied to the screw. If this happens, the moulded thread is still usually unharmed and can still be used. Acme or buttress type threads can be used to decrease the possibility of thread jiunping. 

The overall effectiveness of most containers relates to the design of the bottle neck and closure and the material from which the closure and container are made. Where a flexible material is used, a buttress thread (BS 5789, 1979) is recommended. However, if the material is substantially harder, e.g. HDPE, PP, or PVC, a conventional type 60° thread (BS 1918, R3/2 and R4 finishes for glass) can be employed. 

Fiber, buttress A type of thread used for transmitting load in only one direction. It has the efficiency of the square thread and the strength of the V-thread. 

THREADED CLOSURES - TYPE OF THREADS ACME BUTTRESS MODIFIED OTHER ... 

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