3. Surface-Coating Substances
• refer to any mixture of film-forming materials with the addition
of pigments, solvents, and other additives, which when applied
to a surface and then dried, will yield a thin film that is
functional and decorative in sense.
4. History
• Noah did even utilized a mixture of resinous derivative
called pitch inside and outside the ark which he latter
used as a waterproof.
• The early Phoenicians used the Tyrian purple, also called
as murex which was derived from tiny sea snails
colectively called Muricidae.
• Taong Tabon’s remnants of their figurative sketch on the
walls of caves employing limestones.
5. Surface-Coating Substances: Raw Materials
There are four basic raw materials necessary for the
production of coating substances:
1. Pigment
2. Resin
3. Solvent
4. Additive
6.
7. Pigments
- are colored, organic and inorganic substances that are
widely used in coating industries as well as in ink, plastic,
rubber, ceramic and paper industries whose main function is
to impart color of desired tint and shade.
9. Lithopones
– is a mixed zinc sulfide- barium sulfate pigment that contains
about thirty percent zinc sulfide.
– are used in water-based paints because of their excellent alkali
resistance.
– The synthesis involves the following reactions:
BaSO4 + 4C BaS + 4CO
BaS+ ZnSO4 ZnS + BaSO4
•
10. Titanium Dioxide
– is regarded as the most important white pigment being utilized by
majority of industries today
– is marketed in two crystalline forms, anatase and the more stable
rutile.
– Anatase can be converted to rutile by heating to 700-950°C. TiO2
is widely employed in exterior paints and also in enamels and
lacquers.
11. Titanium Dioxide
– It is manufactured via the following processes:
Sulfate Process
Chloride Process
16. Natural Black Oxide
- This contains 94- 95% Fe2O3. It’s a cheap pigment used in
primers for metals. It can absorb about 10-15 kg of linseed oil per
100 kg of pigment.
Natural Black Oxide
17. Precipitated Black Iron Oxide
- It has blue-black color and manufactured from a solution of-
FeCl2. The solution is taken in wooden tanks and ample amount
of lime water is added to it in order to precipitate iron.
Black Iron Oxide
18. Lampblack
- can be prepared by heating heavy mineral oils in a limited
supply of air. The soot is collected then from multi-compartment
chambers at regular intervals.
Lampblack
26. Cadmium Reds
– a synthetic, inorganic pigment mostly made up of cadmium
sulfoselenide.
– Cadmium red is low in oil absorption with slow drying rate. It is
suitable for all media except for exterior designs.
Cadmium Red
34. Industrial Resin
- these are synthetic polymers that have adhesive, film-forming
and useful reactive properties.
- bind with pigments in order to form a continuous film that is
important for aesthetic and protective purposes.
39. A. Paint
• are stable mechanical mixtures of one or
more pigments.
• Pigments and extenders are carried or
suspended in dryings oils or solvents.
• solvent serves as the drying material to
which other ingredients might be added
40. Types of Paint
• Solvent based
• Water based
1. Emulsion based
2. Latex based
42. Pigment Volume Concentration (PVC)
𝑃𝑉𝐶 =
volume of pigment in paint
vol. of pigment in paint + vol. of nonvolatile vehicle constituents in paint
43. Table 1. Range of PVC for a given paint
Flat paints 50-75% Exterior house paints 28-36%
Semi-gloss
paints
35-45% Metal primers 25-40%
Gloss paints 25-35% Wood primers 35-40%
44. Sample Problem 1
It is desired to make an exterior house
paint of color blue with a reddish undertone.
The manufacturer decided to use a mass ratio
of 2:3, a combination of pigment to resin
(polyvinyl acetate, PVA). Solvent will then be
added to about 25% utilized PVA at a flow rate
of 100 kg/h. Determine if this combination will
qualify as an exterior house paint.The
following empirical data are available as
follows.
45. Sample Problem 1.0
Substance SG, @ 25 ℃
Ultramarine Blue 2.35
Phthalocyanine Blue 1.62
Prussian Blue 1.8
Polyvinyl Acetate 1.19
47. B. Varnish
- refers to a preparation consisting of
resinous matter such as copal or lac,
dissolved in an oil or in alcohol or other
volatile liquid.
49. C. Lacquers
- defined as those non-convertible coatings
and principally as a coating composition
based on a synthetic, thermoplastic, film-
forming material dissolved in organic
solvents that dries by solvent evaporation
or a curing process that produces a hard,
durable finish.
50. D. Enamels
- It is used to get a good gloss because after
drying, the enamels will form a very good
lustrous and glossy finish.
51.
52. Brushing
- This is the simplest method and also the
slowest and most expensive.
- Promotes better wetting of the surface and
can be used in restricted spaces, be useful
for small areas, with less wastage and
contamination of surroundings.
