First, list the ingredients of the recipe. From material suppliers, get the density, non-volatile grade, and price of each material. As shown in Table 1. Calculate volume factor (gal/lb). Based on your knowledge, experience and lab testing, you will estimate the approximate relationship between the ingredients, possibly by weight.
1) Recipe weight
Add ingredients you have considered or used in the recipe (530 lbs).
2) Recipe quantities are the weight of each ingredient multiplied by its volume factor. This will give the volume of the weight used. Total this column (50.97 gallons).
3) Formulation density
Divide the formula weight by the formula volume to get the density of the formula (10.4 lbs/gal).
4) The formulation of "weight non-volatility"
Multiply the weight of each ingredient by its non-volatile content and total (300 lbs). Divide by recipe weight 530 lbs to get 0.5660, multiply by 100 to get 56.6% NV-WT.
5) For the recipe "Non-Volatile by Volume" multiply the volume of each ingredient by its non-volatile content and add up the total (23.29 gallons). Divide by the formula volume (50.97 gallons) to get 0.4569, multiply by 100 to get 45.69% NV-VOL.
6) Pigment to binder ratio (weight)
The ratio of pigment to binder is a weight relationship that can be expressed mathematically in several ways depending on the background of the formulator :
Ratio: Pigment to Binder = 1/1
Percentage : Pigment & Binder = Pigment/Pigment + Binder = 1/1 + 1 = 0.50
Component : Pigment Component/1 or Resin Component = 100/100
7) Pigment volume content (volume)
The standard abbreviation is "PVC", which should not be interpreted as polyvinyl chloride or any other term. Here is a volume relationship expressed as a percentage:
Pigment volume content (PVC, %) = [(pigment volume)/(pigment volume + binder volume)]x100
PVC = ((2.86 + 3.85)/23.29)x100 = 28.81%
The volumetric relationship of pigment to binder seems to be a more critical number. Studies have shown that in a given system, there is a point where pigment levels are high enough to cause degradation of the resulting membrane. This point is known as the "Critical Pigment Volume Content" (CPVC).
8) Convert to 100 gallon recipe
To convert the initial recipe to 100 gallons, divide the initial volume (50.97 gallons) by 100 gallons to get the factor (1.96). Multiply this factor by the weight of each ingredient in the starting recipe to get the weight per 100 gallons. Multiply by the volume of each ingredient in the initial recipe to get the gallons per 100 gallons. If the volume to be made is not 100 gallons, divide the desired volume by the initial volume to get a factor and multiply that by the above number.
