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

Outline Introduction Applications Properties Formulation design experiments Conclusion

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

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

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

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

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

Basic formulation RA-100A MA-100A NCO TDI-based MDI-based Polyols DP-112, DP-256 TP-538 NCO% 6.7-6.9 8.7-8.9 viscosity 4000-6000 3000-5000 catalyst yes no

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

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.

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

Typical properties RA-100A MA-100A adhesion 0.6-0.7(SBR) 1.4-1.5(EPDM) Film T.S 150-170 170-190 Elongation 800-900 500-600 appearance clear opaque Tack free at RT 5-6hr 4-5hr

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

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

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 100-120% for black and around 80% for coloured

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