Date post: | 15-Jan-2016 |
Category: |
Documents |
Upload: | aubrey-chandler |
View: | 222 times |
Download: | 0 times |
www.distrupol.com
Recycling - A Guide to Continuous
Regrind Process
2 www.distrupol.com
More than just Waste???
3 www.distrupol.com
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 www.distrupol.com
Grinder
Feeder(Dryer)
Virginresin
Runners
Parts
Continuous Regrind Process
5 www.distrupol.com
70
1
21
2
6
3
3
4
2
5
> 1
6
50
1
25
2
13
3
6
4
3
5
2
6
1
7
> 1
80
20
40
60
80
% portion of resin that has been moulded x times
Times passed through the machine
30% regrind 50% 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 www.distrupol.com
Example: Delrin* Acetal Resin
Number of times through the cylinder
10 times with 100% regrind
10 times with 50% regrind
Melt index Increase < 10% Increase < 2%
Tensile strength (yield) No difference No difference
Charpy notched impact strength
Reduced by 20% Reduced by 2%
1500 free moleculesat degradation
1500 free moleculesat degradation
40 free molecules +2 chain segment at
degradation
40 free molecules +2 chain segment at
degradation
Homopolymer Copolymer
Degradation-1500 free molecules Degradation-40 free molecules+ 2 shorter chain segments
7 www.distrupol.com
Example: Sarlink* TPR
Require grinders with properly adjusted, very sharp knives and may need considerable cooling, especially for the softer grades.
8 www.distrupol.com
95
100
105
110
115Properties (%)
Regrind level
800% 10% 20% 30% 40% 50% 60%
Flex-modulus
Tensile strength
Elongation
UnnotchedCharpy
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 www.distrupol.com
Example: FR Plastics
This includes, but is not limitedto, the restricted use of regrindthermoplastic material to amounts less than 25% unlessspecified in the individualRecognitions.
10 www.distrupol.com
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 Finally, MUST establish the proper ratio of virgin material to regrind, to give the right virgin material to regrind, to give the right performance for your particular application.performance for your particular application.
www.distrupol.com
A Polymer for Every Application