1. RA-100A與MA-100A的物性比較 (Rubber crumb binder)
研究員 : 胡曉義
Date : 05/31

2. Outline Introduction Applications Properties Formulation design
experiments
Conclusion

3. Introduction Moisture curing one-component polyurethane
Tough, flexible film
Good adhesion
Processing conditions

4. Application Recycled tyre crumb(SBR) EPDM
Typical usage is around 10-20% of binder
Mixed for 5 min or until completely wetted out
Working time in general is up to 2 hrs
Water up to about 1% to facilitate faster curing

5. Athletic surface(MRI Polyteck)
Full Pour System 13mm Olympic standard track system in multiple layers
Sandwich System Mid range two-layer product 10mm SBR base + 3mm EPDM
Spray Coat System For low cost applications 10mm SBR base
Dual Layer System Premium Product with top coat 8mm SBR base

6. Typical properties Almost colourless to amber liquid
Lower than 5000cps
NCO content 8-12%
Prepolymer adhesive used for sport flooring system
Linear or slightly-branched polyols and MDI, MDI/TDI, or TDI alone

7. Physical properties Rubber granule=1-3mm
Volume of binder 10-20% more than
Compression moulding technique=8-10mm thickness
Tensile strength
Elongation at break
Young’s modulus

8. Basic formulation RA-100A MA-100A NCO TDI-based MDI-based Polyols
DP-112, DP-256
TP-538
NCO%
viscosity
catalyst
yes no

9. Experiments Volume of binder=13.5, 16.6, 20, 23.3, 26.3%
Using a 7-day cure
Optimum binder level around 20%, tensile strength=0.75N/mm2, elongation=90%
After a further 14 days
Tensile strength reaching 0.85 and elongation=95%
7 days full cure binder levels around 25%
3 days at 40C 18.3 parts of binder to 100 parts of rubber, reasonable properties

10. Example(Bayer)
A resilient surface was prepared from a mixture of rubber crumb and binder.
polyether polyol (a diol having a molecular weight of 4,000 (PPG-4000 available from Bayer)), di(propylene glycol), and MDI (a 50/50 mixture by weight of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate). The binder components were stirred for two hours at 80.degree. C. to give a polyurethane pre-polymer as a colorless oil.
The resulting pre-polymer binder had an isocyano (NCO) content of 8.0% by weight, a viscosity of 2,700 cP at 27.degree. C. and a gel time of 4.9 hours at 25.degree. C., 20.5.degree. C. dewpoint, and 77% humidity.
The cured film of the binder had a tensile strength of 2,121 psi and an elongation of 622%. A mixture was made of 200 g of the pre-polymer binder and 800 g of recycled rubber crumb having a grain size from 1 to 3 mm. The mixture was shaped with a roller to a uniform thickness of 9.5 to 10.5 mm. The resulting rubber sheet was cured for 7 days at room temperature in the presence of atmospheric moisture.

11. Experiments Rubber crumb / binder=5/1(16.7%) Grain size from 1 to 5 mm
Using a 7-day cure
Optimum thickness around 8mm
Moulding method by roller

12. Typical properties RA-100A MA-100A adhesion 0.6-0.7(SBR) 1.4-1.5(EPDM)
Film T.S
Elongation
appearance
clear
opaque
Tack free at RT
5-6hr
4-5hr

13. Comparison purpose note
Prepolymer batch
Rubber grade
Cure conditions
TDI-based
MDI-based

14. Result and discussion Black crumb tensile strength around 0.6-0.8
Degree of compaction was not achieved
Density difference control

15. Prepolymer formulation
MDI, mixture of MDI and TDI
Adhesion of the binder to the rubber
Key : prepolymer, rubber surface,
Tensile pass the 0.5N/mm2 mark
Elongation % for black and around 80% for coloured

16. Conclusion Standard ratio MDI-based faster than TDI-based
Adhesion strength; EPDM > SBR
Flexibility or elongation; RA-100A > MA-100A
Effect of wet out or pre-coat