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Characteristics of Leneta Paint Charts and Cards |
1. Characteristics of Charts
and Cards
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| Technical Data |
Lacquer Sealer:
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Applied one side only; solvent resistant; non-migrating. |
| Black Areas: |
Printed one side only; non-bleeding, reflectance 1% max.1 |
| White Areas: |
Color retentive; non-fluorescent; reflectance 80% min.1 |
| Thickness2: |
Charts—11 mils (0.28 mm) / Cards—20 mils (0.5 mm) |
| Weightage2: |
Poundage |
lb/Mft2 |
56 charts |
273 charts |
| Grammage |
g/m2 |
74 cards |
361 cards |
| Hole Punching3: |
One hole—1/4" (6mm) diameter
Two holes—3/8" (9.5mm) diameter, 4-1/4" (108mm) between centers. |
1 Measured per ASTM E1347
2 Approximate
3 Indicated by illustrations or in the test. |
| 2. CIE-Y Reflectances of Grays |
| Technical Data |
| Form |
G % |
| 5DX-GW |
46±3 |
| 8H-GW |
46±3 |
| 8K-GW |
46±3 |
| 10H-BG |
34±3 |
| 24B |
Gray Scale |
| CU-1 |
Gray Scale |
| M* |
31±3 |
| S* |
31±3 |
| *Represents additional letters and/or numbers to identify two or more related products. |
| Gray Scale Specifications1 |
| Stripe Number |
Color Difference2 |
Ratio G/W3 |
Reflectance G%4 |
| 1 |
2 ± 12.5% |
0.945 ± 0.007 |
75.6 ± 0.6 |
| 2 |
4 ± 12.5 |
0.893 ± 0.013 |
71.4 ± 1.0 |
| 3 |
8 ± 12.5 |
0.793 ± 0.024 |
63.5 ± 1.9 |
| 4 |
16 ± 12.5 |
0.617 ± 0.042 |
49.4 ± 3.4 |
| 5 |
32 ± 12.5 |
0.347 ± 0.055 |
27.8 ± 4.4 |
| 6 |
64 ± 12.5 |
0.067 ± 0.037 |
5.3 ± 3.0 |
1 As stated for Form CU-1 in ASTM Method D 5150.
2 This is ΔE*ab, the color difference with respect to the white background, expressed in CIELAB units as defined in ASTM Method D 2244.
3 G/W = (1- ΔE*ab/107.7)3 This equation is derived from ASTM Method D 2244 and assumes that for neutral gray versus white, the values ΔE*ab and ΔL* are sufficiently close to be considered equal for the purpose of this test method.
4 These values vary somewhat with the reflectance W of the white area. Values shown here are calculated for W = 80% |
| 3. U.S. - Metric Conversions |
| Technical Data |
| Length: |
1 in = 2.54 cm = 25.4 mm
1 mil = 25.4 μm
1 mm = 39.37 mils
1 ft = 30.48 cm = 0.3048m |
| Area: |
1 in2 = 6.4516 cm2
1 ft2 = 929.0304 cm2
1 m2 = 10.76391 ft2 |
| Volume: |
cc ≈ cm3 ≈ mL; L ≈ dm3
1 in3 = 16.387064 mL
1 ft3 = 28.3168 L = 7.48052 gal
1 gal = 231 in3 = 128 fl.oz = 3785.412 mL
1 fl. oz = 29.5735 mL |
| Weight: |
1 lb = 453.59237 g
1 av.oz = 28.3495 g |
| Density: |
8.3454 lb/gal = 1g/mL = 1kg/L |
| Spreading Rate: |
40.746 ft2/gal = 1 m2/L
4.8824 ft2/lb = 1 m2/kg |
| Weightage (Weight/Area): |
Poundage (lb/Mft2) x 4.8824 = Grammage (g/m2) |
| Temperature: |
°F = 1.8 x °C + 32
°C = 5/9 (°F -32) |
| Notes: (1) Relationships in bold type are exact. (2) 1 gal (Imperial) = 1.20095 gal (U.S.) |
| 4. Spreading Rate vs Film
Thickness |
| Technical Data |
H = spreading rate (whole paint)
T = wet film thickness
t = dry film thickness *
D = whole paint density
d = dry film density *
N = nonvolatile fraction by weight
Nv = nonvolatile fraction by volume
* displacement basis
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| 4.1 Metric Units |
a) H(m2/L) x T(μm) = 1000
b) H(m2/L) x t(μm) = 1000 ND/d
c) H(m2/kg) x T(μm) = 1000/D(kg/L)
d) H(m2/kg) x t(μm) = 1000N/d(kg/L)
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| 4.2 U.S. Units |
a) H(ft2/gal) x T(mil) = 1604.2
b) H(ft2/gal) x t(mil) = 1604.2ND/d
c) H(ft2/lb) x T(mil) = 1604.2/D(lb/gal)
d) H(ft2/lb) x t(mil) = 1604.2N/d(lb/gal)
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| 4.3 Dry vs Wet Films |
a) ND = Nvd
b) t = NvT
c) td = NTD
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| 5. Equations for Spreading Rate Charts |
| (Laboratory operations in grams and mL) |
| Technical Data |
T = wet film thickness
V = volume applied
H = spreading rate
M = weight applied
D = Paint density
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| 5.1 All Metric Units |
a) V(mL) = T(μm) + 10
b) V(mL) x H(m2/L) = 100
c) T(μm) x H(m2/L) = 1000
d) M(g) = V(mL) x D(g/mL)
e) M(g) = T(μm) x D(g/mL) ÷ 10
f) M(g) = 100 D(g/mL) ÷ H(m2/L)
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| 5.2 All U.S. Units |
T(mils) x H(ft2/gal) = 1604.2
5.3 U.S./Metric Units
a) V(mL) = T(mils) x 2.54
b) V(mL) x H(ft2/gal) = 4074.6
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| Note: Equations above in standard type apply only to 0.1m2 (1000cm2) area charts. Those in bold type apply to test areas of any size. |
| 6. General Hiding Power Methodology |
| Technical Data |
| 6.1 Definitions |
Hiding Power is defined as the Spreading Rate required for full hiding over a standard black and white substrate, which is specified in coatings technology to have CIE Y- reflectances of 0.01 (1%) max. and 0.80
(80%) respectively.* Sometimes substrates with other shades or color combinations are employed. Full hiding for visual observations means just short of total extinction of contrast. Photometrically it is defined as 0.98 Contrast Ratio, at which there is likewise a slight amount of visual contrast.
*Specular reflection excluded.
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| 6.2 Film Application |
The objective is to determine the spreading rate at a specified level of dry film opacity, which is usually full hiding as perceived visually or corresponding to the contrast ratio: C = Ro/R0.80 = 0.98. The basic experimental procedure is to apply a uniform film on a suitable test substrate, to observe its opacity either visually or photometrically, and to determine its spreading rate. Since it is not possible to apply a film with precision at a predetermined dry opacity, several such applications need to be made over a range of spreading rates and their results plotted graphically or otherwise interpolated to the desired spreading rate end point. A converse procedure is to apply coatings at a prescribed spreading rate or film thickness, and after drying to measure their contrast ratios or to compare their hiding visually.
The results are only comparative since true hiding power, as defined in 6.1, is a spreading rate. 6.3 Spreading rate (or film thickness) determination— In both visual and photometric hiding power methods, the procedures for observing film opacity are well defined and can be performed with dispatch. The experimental task that is most demanding on the operator’s time and ingenuity is to determine the spreading rate or film thickness of the applied coating with good precision. Although gages are available for measuring wet and dry film thickness directly, it is more accurate to determine the weight of dry paint film on a measured test area and then to calculate the spreading rate or film thickness from relevant portions of the following equations:
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Metric values thus calculated can be converted
to U.S. common units via the following
relationships:
H(ft2/gal) = 40.746 H(m2/L) (3)
H(ft2/lb) = 4.8882 H(m2/kg) (4)
T(μm) = 25.4 T(mils) (5)
D(lb/gal) = 8.3454 D(kg/L) (6)
Powder coatings are usually considered as
being volatile-free, and their dry film and
powder displacement densities (d and D)
as equal. In that case Eq. 2 becomes:
This less rigorous equation avoids the need
to measure d or N.
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| 7. Kubelka-Munk Hiding Power Calc |
| Ask For Details On (K-M) Hiding Power Calculator |
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| Technical Data |
| A. Equipment |
-
The Anti-Sag Meter
- Adjustable Straight Edge
- Drawdown Plate - Regular
- Drawdown Charts* Form 7B black
& white, for light colored paints. Form WB plain white, for dark
colored paints.
- Catch-Papers, Form CP-1
- Pre-shear equipment
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| *With the Low Range Anti-Sag meter use glass or flat metal panels. |
| B. Preparation of Coating |
- Stir well and adjust to 23°C (73.5°F)
- Pre-shear in accordance with one of the pre-shear methods (Pre-Shear by Rapid Mixing
- Solvent Coatings; or Pre-Shear with Syringe
and Needle - Aqueous Coatings), and test immediately
thereafter.
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| C. Application of Coating |
- Attach the straightedge to the drawdown
plate in suitable position.
- Place a test chart on the drawdown plate
under the clip.
- Place the Anti-Sag Meter on the chart,
adjacent to the clip, with its open side toward
operator and its shoulder against the straight
edge.
- Position the Catch-Paper.
- Place a suitable quantity (8-10mL) of
pre-sheared paint directly in front of the blade,
and draw down uniformly at about 6 inches
(150mm) per second.
- Promptly fasten the drawdown to a vertical surface, with stripes horizontal like
rungs in a standing ladder, left edge (thinnest
stripe) at the top, and allow to dry in
that position.
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| D. Rating the Drawdown |
- Note the notch numbers marked on the
Anti-Sag Meter and identify the corresponding
stripes accordingly.
- Ignore the leading and trailing edges,
and observe only the central 5-1/2 inches
(140mm) of blade path, corresponding to
the black area of Form 7B.
- The lowest (thickest) stripe that does
not touch the one below itself is referred to
as the index stripe, and its notch number is
the Anti-Sag Index of the paint.
- For a more precise Anti-Sag Index add
to the index stripe number the product of the
post-index clearance step and the fractional
degree to which it has failed to merge with the
next lower stripe. The fraction is estimated in
accordance with the following table:
|
Degree of
Merger
|
Fraction Unmerged |
Complete
Somewhat more than half
Approximately half
Somewhat less than half |
0
0.25
0.50
0.75 |
| E. Practical Interpretation of Ratings |
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This is empirical and strongly subjective. It
should be emphasized that the Anti-Sag Index
is not a wet film thickness; it is the clearance
of the index groove expressed in Mils, and
as such approximately twice the wet film
thickness of the index stripe with emphasis
on approximate. Neither the Anti-Sag Index
nor the estimated corresponding wet film
thickness is to be construed as calling for a
specific thickness in practice. It is solely a
numerical comparator and acquires practical significance only on the basis of experience.
When a coating is perceived to have optimum
sag resistance by actual application testing,
the Anti-Sag Index is then measured and
thereafter becomes the sag control value for
that particular formulation.
The correct Anti-Sag Index for one product
might be quite different than for another. Latex
paints, for example, would normally have
much higher index values than solvent-borne
coatings. The following qualitative judgments
were based on observations of a series of
trade sales type alkyd gloss enamels, and
are given here as examples only. They are
not to be considered as definitive.
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| Anti-Sag Index |
Sag Resistance |
3
4
5
6
7
8
10
12 |
Very poor
Poor
Poor-fair
Fair
Fair-Good
Good
Very good
Excellent |
The above indices cover the range of the
Standard Anti-Sag Meter, but many coatings
require lower or higher index measurements.
These requirements are met with Low, Medium,
and High Range instruments, making
it possible to measure Anti-Sag Index values
from 1 to 60.
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| 9. Leveling Test Procedure |
| Technical Data |
| A. Equipment |
- The Leneta Leveling Test Blade
- Drawdown Levelness Standards
- Leveling Test Drawdown Plate
- Drawdown Charts
Form WB, for light colored paints
Form 7B for dark colored paints
- Catch-Papers
- Pre-shear equipment
- The Level Luminator
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| B. Preparation of Coating |
- Stir thoroughly and adjust to 23°C
(73°F)
- Strain, and adjust viscosity if and as
necessary.
- Pre-shear in accordance with one of
the pre-shear methods and test immediately
thereafter.
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| C. Application of Coating |
- Position a Catch-Paper on the drawdown
plate.
- Place a chart on the drawdown plate
against the left guide.
- Place the test blade at the top of the chart
with its long arm against the left guide and
toward the operator.
- Place 8-10 mL of pre-sheared coating
in front of the blade and draw down rapidly
at a uniform rate of approximately 60 cm (2
ft) per second.
- Allow to dry in a horizontal position at
23°C (73.5°F).
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| D. Rating the Drawdown |
- After drying cut out a 3 x 5 inch (75 x
125 mm) section, with striations parallel to
the long edge.
- Compare with Levelness Standards under
suitable lighting (Level-Luminator oblique for
white or light colors, ambient specular reflection
for dark colors).
- The number on the matching standard is
the Leneta Drawdown Leveling Value. Rate
perfect leveling as 10 and less than 1 as 0.
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| E. Practical Significance of Numerical Values |
| This is based on subjective evaluations. The
following table represents the collective judgment
of an experienced laboratory group: |
| Drawdown Leveling |
Brushout Value |
1
2
3
4
5
6
7
8
9 |
Very poor
Very poor
Poor
Poor
Poor-Fair
Poor-Fair
Fair
Fair-Good
Good |
| F. Topography of Leneta Drawdown Levelness Standards |
| The following wave amplitudes were measured with a Talysurf 4 profilometer. The data is of interest because it links an objective physical parameter to subjective visual impressions. |
| Standard Number |
Amplitude |
| Mils |
μm |
1
2
3
4
5
6
7
8
9 |
1.000
0.680
0.438
0.310
0.219
0.156
0.109
0.062
0.044 |
25.4
17.3
11.1
7.9
5.6
4.0
2.8
1.6
1.1 |
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