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Trial Number 27

Trial Purpose:

To determine the coefficient of friction for sealer and coating combined.

Date Run:

09/14/2005

Experiment Procedure:

Control of Moisture Content and Temperature
The moisture content at the time of testing will influence results due to the hydroscopic nature of the base materials. Therefore, efforts must be taken to ensure that the moisture content and temperature remain constant during the evaluation period. Ideally, the sample floor should be kept at 65+/-1% relative humidity and 68+/-6 F.

During laboratory testing, conditions were slightly drier, 40% relative humidity, but the temperature was within the given temperature range ~70 F).

Sample Preparation
The flooring material supplied was Hardwood flooring made from Red Oak. The boards were ¾” thick, 2 ¼” wide and cut into 8” sections. Some pieces of the flooring had to be sanded prior to making initial thickness readings to remove residual packing tape adhesive. With the boards cut into 8” coupons, three readings were made using a Brown & Sharpe Micrometer to measure each coupons initial board thickness. Each reading was made to 0.001” and the three values were averaged to give a baseline thickness for the coupons. In addition to the thickness baseline, baselines were established for Gloss, Coefficient of Friction, Impact, Small Area Loads. Procedures for each baseline measurements followed the procedures to be outlined.

Following the establishment of the baselines, three coupons were coated with a supplied floor finish according to the manufacturers’ specifications. The finish was applied using a 1” Pure Bristle 1500 paint brush. To ensure consistent coating application, the finish was leveled off using a 10 mils Precision Gage & Tool Co Dow Film Caster. Three coats were used for each floor finish as this was common number of coating layers suggested by the various manufacturers. Each coating layer was allowed to dry for 2 hours prior to the application of the next coat. Completed coupons were allowed to sit for a minimum period of 24 hours before performance evaluations were conducted.

Coefficient of Friction
The ASTM specified apparatus was replaced with an IMASS, Inc SP-102B-3M90 Slip/Peel Tester (Figure 1). Two types of friction coefficients were measured using this instrument. The first, Static CoF, was determined by obtaining the force required to move the specimen from a stationary position. The second, Sliding CoF (or Kinetic), was found by measuring the average force required to maintain movement at a certain rate. Measured forces will have peaks and valleys in the amount of force needed to keep moving. Average these values results and dividing by the weight of the object will result in the desired coefficient.

The Slip/Peel tester was first adjusted to ensure that the device was properly calibrated for the sled weight being used. A coupon was then placed and clamped onto the bed of the device. The speed of the bed was set to 45”/min. The instrument records two values, the peak, the valley and calculates the average. The device was run three times per coupon for measuring the Static CoF and three times to measure the Kinetic CoF. Each coupon’s value was averaged and then the values for each finish (three coupon averages) were averaged to get one value for the Static Coefficient of Friction and one value for the Kinetic Coefficient of Friction. These values for coated samples were compared to the CoF for the same uncoated coupons.

Coefficient of Friction = Ratio of tractive (pulling) force to the normal force (sled weight): CoF = F/N = (Tractive force)/(Normal Force) = (meter reading)/(sled weight)

Trial Results:

Initial CoF Static  Kinetic
Coupon # Peak Valley Average Peak Valley Average
a 653 562 566 597 578 586
  781 577 588 586 571 578
  699 573 585 609 588 592
b 711 583 594 588 562 568
  714 576 586 607 568 572
  721 572 575 595 557 565
c 763 626 626 595 561 582
  696 592 593 583 555 568
  704 572 588 584 566 570
Coated CoF  Static Kinetic
Coupon # Peak Valley Average Peak Valley Average
a 877 617 670 762 637 672
  898 616 673 734 607 674
  819 617 669 749 618 676
b 915 643 692 779 675 698
  1027 671 703 738 682 704
  970 676 701 741 678 697
c 829 658 666 722 629 662
  891 640 662 689 639 664
  819 650 668 689 641 666

Averages  

Static  Kinetic 
Peak Valley Average Peak Valley Average
711 571 580 597 579 585
715 577 585 597 562 568
721 597 602 587 561 573
716 581 589 594 567 576

Coated

Static Kinetic
Peak Valley Average Peak Valley Average
865 617 671 748 621 674
971 663 699 753 678 700
897 658 676 717 649 674
911 646 682 739 649 683

Comparison

Final - Initial Static  Kinetic
  Peak Valley Average Peak Valley Average
Capitol Polyurethane Gloss 136 182 216 248 212 223
Pro Finisher Water Based Polyurethane for floors 381 65 183 317 74 156
Pro Finisher Water Based Sanding Sealer -8 43 62 77 46 54
Quide SA Aqua Deva Metro 24 25 48 52 36 49
Capitol Hydro 202 Satin 348 331 398 477 349 419
SafeCoat BP Satin 158 40 78 114 63 71
SafeCoat BP Gloss 306 103 212 414 169 238
Kiilto -337 -266 -268 -277 -254 -271
Kiilto + Primer 63 -31 71 123 -50 48
Pro Finisher Water Based Sanding Sealer & Polyurethane 195 65 93 146 82 107

Success Rating:

A follow up test, usually based on company input.

Conclusion:

The combined sealer and coating performed better than the sealer alone and about as well as the coating alone.

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