Flexo and Gravure inks are formulated from the following components:
|
Components
|
Content
|
Principal functions
|
|
Solvents
|
50 – 75%
|
Volatile organic products used to solubilise the polymers. Principal families: alcohols, esters, ketones, glycols and water. |
|
Cellulosic, vinylic,
acrylic and polyamide polymers |
15 – 30%
|
Constituents of the binder (solvent + polymer) that largely determines the adhesion on substrates, the gloss and the mechanical, physical and chemical properties of the ink.
|
|
Organic or mineral
pigments Organic colorants |
8 – 20%
|
Pigments chosen as a function of the binder and the fastnesses required by the application. Constituents that enable intense and very transparent inks to be obtained. |
|
Additives
|
3 – 5%
|
Products that confer specific properties to the ink such as rheology, adhesion, rub and scratch resistance, anti-foaming effect, etc.
|
Typical Flexo – Gravure ink formulation
Principal polymers
In water based inks, two types of acrylic polymers are used:
• Polymers in emulsion or dispersion, which improve the drying, gloss, adhesion and
water resistance of inks.
• Polymers in solution, which improve pigment wetting and make re-solubilising
and cleaning easier.
In solvent based inks, the various families of polymers cited above are used singly
or as mixtures, depending on the application and the final properties required of the
print.
In water based inks, two types of acrylic polymers are used:
• Polymers in emulsion or dispersion, which improve the drying, gloss, adhesion and
water resistance of inks.
• Polymers in solution, which improve pigment wetting and make re-solubilising
and cleaning easier.
In solvent based inks, the various families of polymers cited above are used singly
or as mixtures, depending on the application and the final properties required of the
print.
Principal solvents
|
Names
|
Evaporation
index |
Flash point (°C) |
Risks
|
|
Petroleum spirit C
|
2
|
- 20
|
F
|
|
Ethanol 95
|
8.3
|
13
|
F
|
|
Ethanol 99
|
8.3
|
13
|
F
|
|
Isopropanol
|
10
|
12
|
F
|
|
n-Propanol
|
11
|
14
|
F
|
|
Secondary butanol
|
33
|
24
|
F, X Harmful
|
|
Ethyl acetate
|
2.9
|
- 4
|
F
|
|
Isopropyl acetate
|
4.2
|
7
|
F
|
|
Methoxy propanol
acetate |
43
|
54
|
F
|
|
Ethoxy propanol
|
33
|
42
|
F
|
|
Methyl ethyl ketone (MEK)
|
3.3
|
- 4
|
F, X Irritant
|
|
Methyl isobutyl ketone
(MIBK) |
2
|
14
|
F, X Harmful
|
|
Cyclohexanone
|
40
|
43
|
F, X Harmful
|
|
Monopropylene glycol
|
-
|
107
|
|
The solvent is chosen as a function of the application, the desired drying speed and the type of polymers used. The lower the evaporation index (ether = 1), the more volatile the solvent and the faster the drying speed.
The flash point is the minimum temperature at which the solvent can ignite in the presence of a heat source (spark, naked flame, etc.).
The flash point is the minimum temperature at which the solvent can ignite in the presence of a heat source (spark, naked flame, etc.).
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