Floor covering adhesive viscosity

USE

For linoleum and other types of resistant floor coverings.

PROBLEM

Heavy-duty flooring adhesives generally produce widely varying viscosity test results when using standard viscometers. The RST-SST rheometer in a performance test with modulus calculation (slope of the line leading to the yield strength) quickly qualifies the product with consistently reproducible results, thus providing an improved quality control procedure.

TEST EQUIPMENT

Instrument: RST-SST Soft solids tester

Geometry: VT-20-10

Pallet spindle software: RHEO 3000

TEST METHOD

Shear Rate Control (CSR) with the paddle spindle rotating at low speed.

PROGRAM

• A step

• Start RPM = 0.5

• End RPM = 0.5

• Time = 30 seconds

• Plot = stress on the Y axis, strain on the X axis

• Regression analysis using values up to 40 % maximum shear stress

Four types of adhesives are evaluated in Figure 1. The modulus determination has been defined to evaluate up to 40% of the maximum stress value. The following modulus values have been reported:

Sample A: G = 35550 Pa

Sample B: G = 34419 Pa

Sample C: G = 28862 Pa

Sample D: G = 16652 Pa

The pallet axis geometry easily accommodates adhesives of varying consistency and produces a repeatable curve that allows for rapid pass / fail testing. In FIG. 1, sample D has the lowest modulus and therefore spreads the most easily. Samples A and B have the highest modulus and are comparatively stiffer on plating.