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Trial Number 3

Client Number 260

Project Number 1

Trial Purpose:

To evaluate impact resistance for various floor finishes

Date Run:

06/30/2006

Experiment Procedure:

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 64% relative humidity and the temperature was ~74 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.

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 proper coating application rates, the coatings were applied via pipettes to surface. Three coats were used for each floor finish as this was common number of coating layers suggested by the various manufacturers.

The first two coatings were allowed to dry for 2 hours prior to the application of the next coat. The second coat for the current process was allowed to dry overnight before the application of final coat. The Completed coupons were allowed to sit for a minimum period of 24 hours before performance evaluations were conducted.

Falling-Ball Indentation
This test is designed to obtain a measure of the resistance of a flooring finish to impacts from dropped objects. Four drops were made for each coupon for a total of twelve drops per finish. Each drop was made at a 6” intervals starting at 6” and ending at 72”. The ball used for the drops was a 440-C stainless steel 2” diameter ball, grade 100. The dropping apparatus used is shown in Figure 2. Carbon paper was placed on the coupon surface to assist in determining where the indentation was made.
Figure 2. Dropping Apparatus
The same Brown & Sharpe Micrometer was used to measure the indentations to the coated coupons. A plot was made of the height of drop and residual indentation and the slope of the best fit line was calculated. From the plots, the intercept of the height of drop at 72” was recorded as the index of indentation resistance. Results for each finish were compared each other.

Trial Results:

Impact depth was calculated by subtracting the average initial coating thickness from the thickness measured at the point of impact for each drop height. The initial average coating thickness was calculated from the three initial coating measurements made for each coupon.

*Due to the construction of the floor boards and the location of the impact from the ball, additional baseline readings had to be recorded for certain areas on the coupons. These values are designated by the coupon number and "A" (alternate).

  Coated Thickness     Drop Height
Coupon Middle End 1 End 2 6 12 18 24 30 36 42 48 54 60 66 72
1 0.7512 0.7498 0.7549 0.7437     0.7320                
1A 0.6755 0.6770 0.6693   0.6717 0.6554                  
2 0.7535 0.7566 0.7560         0.7397 0.7288            
2A 0.6751 0.6699 0.6811             0.6518 0.6486        
3 0.7588 0.7609 0.7585                   0.7227    
3A 0.6767 0.6722 0.6776                 0.6549   0.6470 0.6302
4 0.7648 0.7702 0.7655     0.7521 0.7491                
4A 0.6727 0.6742 0.6751 0.6720 0.6667                    
5 0.7560 0.7582 0.7601         0.7518 0.7266   0.7176        
5A 0.6707 0.6682 0.6744             0.6543          
6 0.7548 0.7591 0.7598                 0.7359 0.7291 0.7208 0.7178
6A 0.6702 0.6714 0.6685                        
7 0.7575 0.7555 0.7611   0.7508   0.7264                
7A 0.6580 0.6719 0.6549 0.6541   0.6501                  
8 0.7427 0.7477 0.7460         0.7350   0.7255          
8A 0.6627 0.6676 0.6661           0.6449   0.6407        
9 0.7548 0.7574 0.7547                     0.7252  
9A 0.6748 0.6772 0.6682                 0.6461 0.6449 0.6378 0.6351
10 0.7456 0.7467 0.7503 0.7435 0.7391 0.7287 0.7203                
10A 0.6778 0.6830 0.6750                        
11 0.7582 0.7613 0.7652           0.7317   0.7311        
11A 0.6709 0.6683 0.6807         0.6653   0.6477          
12 0.7657 0.7644 0.7653                   0.7431    
12A 0.6860 0.6844 0.6856                 0.6539   0.6483 0.6383
13 0.7501 0.7471 0.7470 0.7487 0.7455 0.7373 0.7312                
13A 0.6667 0.6700 0.6685                        
14 0.7582 0.7575 0.7539         0.7385 0.7316   0.7287        
14A 0.6870 0.6822 0.6837             0.6737          
15 0.7471 0.7448 0.7484                     0.7231 0.7135
15A 0.6744 0.6721 0.6682                 0.6458 0.6429    

Calculated Impact Depths

    Drop Height
Coating Coupon 6 12 18 24 30 36 42 48 54 60 66 72
  1 0.0112 0.0053 0.0201 0.0178                
CP 2         0.0163 0.0272 0.0233 0.0265        
  3                 0.0227 0.0361 0.0297 0.0420
  4 0.0031 0.0075 0.0127 0.0164                
MCP 5         0.0083 0.0316 0.0164 0.0384        
  6                 0.0239 0.0307 0.0340 0.0413
  7 0.0008 0.0103 0.0079 0.0291                
BO 8         0.0110 0.0212 0.0172 0.0269        
  9                 0.0221 0.0233 0.0370 0.0421
  10 0.0068 0.0112 0.0169 0.0264                
BW 11         0.0154 0.0335 0.0232 0.0302        
  12                 0.0317 0.0222 0.0377 0.0461
  13 -0.0017 0.0015 0.0128 0.0159                
Blank 14         0.0154 0.0223 0.0133 0.0288        
  15                 0.0224 0.0253 0.0240 0.0313

Graphs for each product are shown in Figure 2
From the graphs, slopes were calculated and the index was calculated for the interception point for 72". The lower the index, the less the indentation and the better the coating's resistance.

Product Slope of Best Fit Line Index of Indentation Resistance

Uncoated   0.196        
Product Slope of Best Fit Line Index of Indentation Resistance Rank   x y
CP 1714.8 0.0420 4   0.0419 72
MCP 1692.1 0.0426 3   0.0425 72
BO 1791 0.0402 5   0.0402 72
BW 1560.4 0.0461 2   0.0461 72
Blank 2138 0.0337 1   0.0336 72

Success Rating:

A cleanliness study, addressing only various analytical techniques.

Conclusion:

The Bona Water based coating mix had the lowest index of indention for the coated boards followed by the modified current practice.

The uncoated wood samples had a lower index of indention than any of the coated samples. The coating thicknesses were easier to displace by the steel ball then the hard wood surface was.

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