HM-RWX Latex Mechanical Stability Tester

Product Introduction

The HM-RWX Latex Mechanical Stability Tester is a high-speed stirring instrument built by HM Instruments to determine the mechanical stability of concentrated natural rubber latex and synthetic latex. A weighed latex sample is sheared inside a flat-bottomed glass barrel until coagulum first appears; the elapsed time, reported as mechanical stability time (MST), quantifies how well the latex will survive pumping, mixing and dipping-line agitation.

The instrument satisfies the requirements of GB/T 8301-2008 (Concentrated natural rubber latex — Determination of mechanical stability) and SH/T 1151-1998 (Determination of high-speed mechanical stability of synthetic latex). Test speed is held at 14,000 rpm ±50 rpm, and mixing shaft deflection is limited to ≤50 μm, both tighter than the corresponding national-standard limits of ±200 rpm and ≤200 μm. Two interchangeable stirring discs are supplied — Ø 20.83 mm for natural latex and Ø 36.12 mm for synthetic latex — so one bench unit covers both test methods.

A frequency-converter LED readout shows live speed at 1 r/min resolution with indication error ≤0.1%, and the spindle can be released from 2,000 to 24,000 r/min for method development. Latex concentrate producers, glove and foam manufacturers, adhesive formulators and research institutes use the HM-RWX for incoming inspection, batch release and stabiliser screening. Background on test-method selection is collected in the HM-RWX latex stability testing guide.

Testing Items

• Mechanical stability time (MST) of concentrated natural rubber latex to GB/T 8301-2008
• High-speed mechanical stability of synthetic latex to SH/T 1151-1998
• Incoming inspection of centrifuged and creamed natural latex concentrate
• Batch release testing of ammonia-preserved and low-ammonia latex
• Stabiliser and surfactant dosage screening during compound development
• Process troubleshooting for dipped goods lines producing gloves, condoms and balloons
• Stability verification of latex foam, mattress and pillow compounds
• SBR, NBR, CR and acrylic latex testing for adhesives, carpet backing and paper coating
• Teaching and research work in rubber, polymer and materials laboratories

Functional Performance and Features

1. Stirring speed maintained at 14,000 rpm ±50 rpm, one quarter of the ±200 rpm band permitted by the national standard, keeping MST values comparable between operators, shifts and laboratories
2. Mixing shaft deflection ≤50 μm against a national-standard limit of ≤200 μm, suppressing the eccentric shear that artificially shortens apparent stability time
3. Two stirring discs included: Ø 36.12 ±0.03 mm for synthetic latex and Ø 20.83 ±0.03 mm for natural latex, both 1.57 ±0.05 mm thick
4. Frequency converter LED display reports live spindle speed at 1 r/min resolution with indication error ≤0.1%
5. Wide speed envelope from 2,000 r/min to 24,000 r/min; the knob is set to 14,000 r/min for standard runs and can be reconfigured for non-standard shear studies
6. Flat-bottomed glass test barrel with height >100 mm, 58 mm inner diameter and 63 mm outer diameter reproduces the standard vessel geometry
7. Mixer rod low-end diameter of 6.3 mm matches the shaft dimension specified for the test method
8. Single-key operation — clamp the cup holder in the raised position and press RUN on the controller to begin the test
9. Cooling water pump and pipe supplied as standard, carrying away frictional heat that would otherwise bias the endpoint
10. Rigid 400 mm × 350 mm × 720 mm frame with adjustable levelling feet holds the spindle vertical on any bench
11. Works in 10 °C to 40 °C and below 85% RH, so no dedicated climate-controlled room is required
12. Complete delivery kit: instrument mainframe, special glass cup, natural latex mixer, synthetic latex mixer, cooling water pump and cooling water pipe

Main Parameters

Technical Parameters

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