**Density**

Density paint is:

Total sum by weight of each ingredient in paint |

Total sum by volume of each ingredient in paint |

2.

**Solid content**

Solid content by weight of paint is:

Total sum by weight of each solid ingredient in paint x 100% |

Total sum by weight of each ingredient in paint |

Total sum by volume of each solid ingredient in paint x 100% |

Total sum by volume of each ingredient in paint |

3.

**Pigment Volume Concentration**

Total sum by volume of all pigments + extenders in paint x 100% |

Total sum by volume of each ingredient in paint |

4.

**Critical Pigment Volume Concentration**

The best way to determine the critical PVC of a paint is to measure the volume of the dry pigment/extender mix of a paint in a centrifuge and to calculate the CPVC as follows:

CPVC = (calculated volume pigment/extender mix / volume after centrifuge) x 100

or

CPVC = ( f x G x 100) / (dPi x Va)

f = ratio weight pigments and total weight solid content paint

G = weight of dry film

dPi = density of pigment/extender mix

Va = geometric volume of paintfilm (e.g. 250 micron wet filmthicknes x length x width)

A theoretical calculation which estimates the approximate CPVC is:

CPVC = (volume pigment+extender x 100) / (volume pigment+extender) + ((average o.a. pigment+extender) / 0,93)

5.

**Extender replacement**

To calculate an extender replacement by weight by another extender and maintaining PVC:

E =

__A1 x D2__

A2 x D1

E = factor to multiply with original extender weight to calculate weight substituting extender

A1 = OA of original extender

A2 = OA of substituting extender

D1 = density of original extender

D2 = density of substituting extender

6.

**Crosslinking percentage of two component products**

· Epoxies

· Epoxies

Equivalent weight epoxy component base paint is:

Weight base paint |

Weight epoxy resin (1) + Weight epoxy resin (2) + |

Eq.w.epoxy resin (1) Eq.w. epoxy resin(2) |

Equivalent weight amine component harder is:

Weight harder |

Weight amine (1) + Weight amine (2) + |

Eq.w. amine (1) Eq.w.amine (2) |

Crosslinking percentage =

Weight harder x Eq.w. base component x 100% |

Weight base x Eq.w. harder component |

**Polyurethanes**

Equivalent weight polyol component base paint is:

Weight base paint |

Weight polyol resin (1) + Weight polyol resin (2) + |

Eq.w.polyol resin (1) Eq.w. polyol resin(2) |

Equivalent weight isocyanate component harder is:

Weight harder |

Weight isocyanate (1) + Weight isocyanate (2) + |

Eq.w. isocyanate (1) Eq.w.isocyanate (2) |

Crosslinking percentage =

Weight harder x Eq.w. base component x 100% |

Weight base x Eq.w. harder component |

7.

**Calculation the amount of amine to neutralize water-reducible resins**

Equation:

__A = R (AN) E__

56.100

Where:

A = weight of amine

R = weight of resin, non volatile

AN = acid number resin, non volatile

E = equivalent weight of amine

8.

**Starting point amounts of hydroxy / carboxy / amide containing resins in melamine / urea resins combinations in oven cured systems**

Let:

x = hydroxyl number (mg of KOH to neutralize the organic acid required to esterify the hydroxyl groups present)

y = acid number (mg of KOH required to neutralize one gram of resin)

z = amide number (mg of KOH equivalent to reactivity of the amide groups present-by calculation)

Then:

__56 grams (mol.wt. KOH)__= gram mol. of resin to be crosslinked

x + y + z (mg)

Example: the equivalent weight of a melamine resin is 130

If a polyester resin has a hydroxy number of 60, an acid number of 5 and an amide number of 0, the gram-mol weight of the polyester is:

__56 grams__= 861,5 grams

60+5+0 mg

Or the starting levels for the binder may be polyester / melamine resin = 861,5 / 130

Or polyester / amino = 87 /13 by weight on solids

9.

**Volatile Organic Compounds**(VOC’s with vapour pressure > 0,01 kPa at 20 C)

VOC =

__weight volatile organic material (g/l)__

Volume paint (without water

VOC =

__100 – NV% - water%__x 1000 (g/l)

(100/density) – water%

For solvent based coatings the formula simplifies to:

VOC = (100 – NV%) x 10 x density (g/l)

10.

**Theoretical spreading rate paint at given filmthickness:**

__Volume solids__= liters/m2

Filmthickness in microns : 10

__Volume solids__= kg/m2

(Filmthickness : 10) x density solids paint

Price per m2 at given film thickness:

__Price per liter__Theoretical spreading rate in liters

Relation thickness steel construction and surface:

Thickness s of steel in mm | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 15 | 25 | 50 |

Surface in m / tonne steel | 254 | 127 | 85 | 63 | 51 | 42 | 36 | 32 | 28 | 25 | 17 | 10.1 | 5.1 |

11.

**Required air quantities to stay below MAC levels**:

∑ ( TLV per ingredient x weight %)

12.

**Required air quantities to stay below lowest explosion limits**:

∑ ( LEL per ingredient x weight %)

13.

**General formulae for mixing liquids**A = C – B

B =

__C (a – c)__

a – b

C =

__B (a – b)__

a – c

Where:

A = weight of original liquid

a = its content in % by weight

B – weight of diluent

b = its content in % by weight

C = weight of prepared mixture

c = its content in % by weight

For water as diluent, b = 0

14.

**HLB (hydrophylic – lipophylic – balance) of surfactants and their activity features**

0 – 4 = defoaming

3 – 7 = emulsifying

7 – 15 = penetrating

7 – 20 = emulsifying

12 – 20 = detergency

15 – 20 = solubilising

15.

**Mixing rules by using mixture-cross**

How much of each solution has to be mixed to get a 62% solid solution of a 54% solids solution with a 92% solids solution?

30 parts by weight of 54% solid solution must be mixed with 8 parts by weight of 92% solid solution to yield a 62% solid solution.

92 - 62 = 30 pbw 54% solution

62 - 54 = 8 pbw 92% solution