best resin for cap/closure
best resin for cap/closure
(OP)
Hi Everyone:
I have inherited a mold that produces a tamper evident cap almost identical to those used in plastic milk/water jugs. The cap has a ring that sits below the cap body that must break away from the cap at 9 evenly divided points along the circumference when the cap is initially unscrewed from the bottle (the ring stays on the bottle neck finish). The problem we are having is that it requires excessive torque to break the cap from the ring. We have samples in Exxon HDPE HMA 016. I am trying to find out which physical properties to concentrate in order to make an educated resin selection for our next few sample runs. Would it be the tensile strength, i.e. a lower tensile strength will allow the cap to break away from the ring? Thanks in advance for your help.
I have inherited a mold that produces a tamper evident cap almost identical to those used in plastic milk/water jugs. The cap has a ring that sits below the cap body that must break away from the cap at 9 evenly divided points along the circumference when the cap is initially unscrewed from the bottle (the ring stays on the bottle neck finish). The problem we are having is that it requires excessive torque to break the cap from the ring. We have samples in Exxon HDPE HMA 016. I am trying to find out which physical properties to concentrate in order to make an educated resin selection for our next few sample runs. Would it be the tensile strength, i.e. a lower tensile strength will allow the cap to break away from the ring? Thanks in advance for your help.






RE: best resin for cap/closure
Dan - Owner

http://www.Hi-TecDesigns.com
RE: best resin for cap/closure
Introducing notches to the design helps.
If it did work, then stopped working, someone probably polished the mould and removed some sharp edges at the intended break point.
A little talc in the resin or lower molecular weight will probably help.
Regards
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RE: best resin for cap/closure
RE: best resin for cap/closure
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