Presentation on theme: "Www.distrupol.com Recycling - A Guide to Continuous Regrind Process."— Presentation transcript:
Recycling - A Guide to Continuous Regrind Process
2 More than just Waste???
3 More than just Waste??? Example 1: Using 1000kg/month of Acetal (£2.84/Kg). Weight of the runner system is 100Kg (10% of Part weight), which means you are throwing away £284/month and £3408/year. Example 2: Using 5000kg/month of PP (£0.95/Kg). Weight of the runner system is 1000Kg (20% of Part weight), which means you are throwing away £950/month and £11,400/year. Don’t forget Storage cost, Handling cost, Collection cost, Transportation cost, Tax liability?
4 Continuous Regrind Process
> > % portion of resin that has been moulded x times Times passed through the machine 30% regrind50% regrind Melt Quality Regrind For example, if 30% regrind is used in a continuous operation, only 2% of the regrind has passed through the machine 4 times and less than 1 % has passed through the machine 6 times or more.
6 Example: Delrin* Acetal Resin Number of times through the cylinder 10 times with 100% regrind 10 times with 50% regrind Melt indexIncrease < 10%Increase < 2% Tensile strength (yield)No difference Charpy notched impact strength Reduced by 20%Reduced by 2% HomopolymerCopolymer Degradation-1500 free moleculesDegradation-40 free molecules + 2 shorter chain segments
7 Example: Sarlink* TPR Require grinders with properly adjusted, very sharp knives and may need considerable cooling, especially for the softer grades.
Properties (%) Regrind level 80 0%10%20%30%40%50%60% Flex-modulus Tensile strength Elongation Unnotched Charpy Example: Zytel* GR Nylon 6.6 Glass fibre reinforced materials shows higher sensitivity to recycling, due to the breakage of fibres during the regrinding process. Ideally ground hot to minimise glass fibre breakage.
9 Example: FR Plastics This includes, but is not limited to, the restricted use of regrind thermoplastic material to amounts less than 25% unless specified in the individual Recognitions.
10 Keep in Mind Higher the quality of the regrind, higher the quality of the finish part. Treat the regrind as if it’s virgin material. Maintain a constant ratio of virgin resin to reground material. Particle size of reground material to be uniform and similar to the virgin material. Make sure the grinder blades are kept sharp and properly set to minimise fines. Clean grinders and regrind containers frequently. Finally, MUST establish the proper ratio of virgin material to regrind, to give the right performance for your particular application.