Offset Printing 1000 Questions (174-186)

174. What is ink accessories? What are the commonly used offset printing ink accessories?
A: In actual use of inks, the physical and chemical properties and printability of the original ink may be inappropriate due to the differences in the type and nature of the paper used, the printing process, and the technical conditions of the workshop process, or different concentrations of the ink may need to be formulated. , Hue of the color or complex ink. Auxiliaries added to meet and adapt to these process conditions and requirements in the actual printing process are called ink accessories. Commonly used offset printing ink accessories are consistency modifiers, viscosity modifiers, dryness modifiers, dilutants, and the like.
175. What is an ink consistency adjuster?
A: The ink consistency modifier is a collective name for accessories that have the ability to increase and decrease the ink consistency. Ink consistency regulators are classified into thickeners and thickeners according to their properties.

176. Thickeners and their performance?
A: An auxiliary additive that can increase the consistency of the ink without affecting its structural function is called a thickener. There are two types of thickeners: fat type and resin type. The thickening agent is generally a tan transparent thick fluid having a viscosity of about 50 to 100 Pa·s, a small fluidity, and a large viscosity. Adding it to thin inks can not only increase the consistency of the ink, but also increase the viscosity, and accordingly change the viscosity, stringiness, and fluidity.

177. Thickeners and their performance?
A: An auxiliary additive that can reduce the consistency of the ink without changing its structure and function is called a thickener. Thickeners are grease type, resin type and solvent type 3 categories. The thickening agent is generally a light yellow transparent thin fluid having a viscosity of about 0.14 to 0.16 Pa·s, a high fluidity, and a low viscosity. Adding it to a thick ink can not only reduce the consistency of the ink, but also reduce the viscosity and increase the fluidity, and accordingly change the viscosity and stringiness.

178. What is an ink viscosity modifier?
A: Ink viscosity modifiers are collectively known as excipients that increase or decrease ink viscosity. Ink viscosity modifiers are classified into two types, viscosity increasing agents and retreating agents according to their properties.

179. What are the tackifiers and their properties?
A: Tackifiers are auxiliary additives that improve the viscosity of the ink. There are two types of tackifiers: resin type and fat type. The thickening agent is generally a brown transparent thick fluid having a viscosity of about 50 to 100 Pa·s, a small fluidity, and a large viscosity. Adding it to the ink can not only increase the viscosity of the ink, but also increase the consistency and decrease the fluidity at the same time, and accordingly change the viscosity and the stringiness.

180. How to remove the adhesive and its performance?
A: The relieving agent is an auxiliary additive that has the function of reducing the viscosity of the ink. Retacking agent is generally light yellow translucent paste, does not have fluidity, has the effect of inhibiting drying, and has a good affinity with the ink. Adding it to the ink body not only reduces the viscosity of the ink body, but also does not increase the fluidity, does not change the consistency, and shortens the drawing. In use, can be directly transferred into the ink, the amount should generally be controlled at 3% to 5%, when excessive will cause poor delivery, dirty layout, affecting the speed of fixation and gloss.

181. What is a dry ink conditioner?
A: The ink dryness adjuster is a collective name for accessories that promote or inhibit ink dryness. Can be divided into two categories of driers and dry agents.

182. What is a driers?
A: The driers are collectively known as metal salt excipients that promote the oxidation of polymeric dry vegetable oils in the ink and polymerize to form a film. They are commonly called dry oils. Can be divided into liquid driers (red dry oil) and cream driers (white dry oil) two categories.

183. Red dry oil and its performance?
A: The red dry oil is made from cobalt naphthalate (or linseed oil), rosin and mineral oil (ink oil). It is generally a brownish-purple liquid fluid with strong oxidative drying properties. Into the ink, can make the ink layer from the surface and the inside to promote the oxide film.

184. White dry oil and its performance?
A: White dry oil is made of lead borate, manganese borate, cobalt naphthalate, and resin oil (or polymeric drying oil), mineral oil (ink oil) mixed ground, generally pink paste fluid, with better Oxidation, polymerization drying. Into the ink, the surface and the bottom of the ink layer can be oxidized at the same time and condensed into a thin film.

185. How to choose red dry oil and white dry oil?
A: The dryness of the ink is not only affected by the tightness of the paper, ink absorption, smoothness, pH, and the nature of the pigment or auxiliary materials in the ink, but also affected by the temperature and humidity of the workshop, so it should be used with caution. In lithographic offset printing, white dry oil is mainly used, and its amount is generally controlled within 5%. Most of the red dry oil used in the final color sequence, or configuration dry white oil use, the amount of general control in 0.5% to 1%.

186. Ink drying agent and its performance?
Answer: The anti-drying agent is the collective name for the auxiliary materials that enable the ink to have the ability to suppress or retard the oxidative conjunctiva. It is also called an antioxidant.
Ink drying agent is made by dissolving antioxidants (such as phenols or anilines) in polymeric dry vegetable oil (or ink oil). It is generally a transparent fluid with strong dryness and a certain viscosity. Into the ink, can inhibit and delay the ink layer to produce a dry knot, but does not affect its fixation speed and color.
Normally, when the dry stop agent is used to stop the machine halfway or the ink roller is dry, the amount of the dry stop agent is generally controlled at 0.3% to 1%. If it must be directly transferred into ink, it should be cashed in. If it is too long, it will weaken its effect.

From - <Printing Technology>