Help for extrusion flow problem

Hello Im new into extrusion and need some help Om extruding pe with a self made extruder i have lots of hdpe and few ldpe my
need is a soft flexible end product is there a way to make hdpe as soft and flexible as ldpe ??? Some additive perhaps ? Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.