1000 Offset Printing (187-199)

187. What is ink thinner?
A: The excipients used for light-colored inks are usually called ink thinners. Can be divided into two types of fat and resin type. Grease-type diluting agent is divided into two kinds: transparent oil and white oil, resin-type diluting agent is divided into two kinds of bright light and light dip.
In the offset printing color, the diluting agent is usually used according to the type of the original ink. For resin-based offset printing inks, light-based pastes are the main choice; for oil-based offset printing inks, transparent dipping inks are often used, and an appropriate amount of driers is added. White oil is used only for bottom printing or as a lightening agent for low-grade prints.

188. What is the composition and properties of transparent oil?
A: The transparent oil is a mixture of aluminum hydroxide and polymeric dry vegetable oil. It is usually a light brown, transparent, creamy fluid with high transparency, low viscosity, slow dryness, and poor luster. Into the ink, can reduce the ink color, accompanied by a slight viscosity reduction, and does not affect the original ink color, but the gloss is poor.

189. How is the composition of white oil and its performance?
A: Oil type white oil is made by mixing and grinding aluminum hydroxide, polymeric dry vegetable oil, and waxes. Water-type white oil is made of stearic acid and then magnesium carbonate is compounded. White oil is generally a milky white translucent creamy liquid, with slow dryness, poor luster and other properties. Into the ink, can reduce the ink color, accompanied by viscosity reduction.

190. What is the composition and properties of the bright paste?
A: The bright paste is made of rosin modified phenolic resin, polymeric dry vegetable oil, gelling agent, wax, mineral oil, and driers. The bright lacquer is generally a yellow-brown transparent paste fluid and has the characteristics of strong water resistance, moderate dryness, strong luster, poor plasticity, etc., and has slight back-roughening during storage. The bright paste into the ink, can reduce the ink color, enhance gloss.

191. What is the composition and performance of the lighter?
A: The lightening agent is made of rosin-modified phenolic resin, polymeric dry vegetable oil, aluminum stearate, waxes, mineral oil, and driers, etc., and is obtained by refining or grinding. Diluter is generally a transparent or translucent paste or slurry fluid, viscosity, fast drying, good gloss, sensitive to temperature. During storage, there is a slight degree of coarsening. Diverting agent into the ink, can reduce the ink color, enhance gloss, improve the transparency of the ink and printing effect.

192. What is an ink agent?
A: Ink anti-knit agents are the collective names for inks that have prevention or mitigation of certain malfunctions. According to the role it plays after adding ink, there are several kinds of anti-adhesive agent, anti-crystallization agent and anti-gelling agent.

193. What is a detackifier? How is its performance?
A: The anti-adhesive agent is a collective name for accessories that have the function of reducing ink stickiness and preventing stickiness. The anti-adhesive agent is a milky white paste colloid, which is adjusted into the ink, which can reduce its viscosity and prevent sticking and sticking of the printed sheets due to the accumulation.
At present, there is no finished product to be sold, and the user must prepare it by himself. In the production, corn starch is used to be used as an anti-adhesive agent in grease type or ordinary resin type offset printing ink. The dosage is generally controlled within 3%.

194. What is anti-crystallization agent? How is its performance?
A: The anti-crystallization agent is the collective name for the auxiliary materials that make the ink have the function of eliminating the crystallization of the ink film. The anti-crystallization agent is a paste. Into the second color ink, the first color ink has crystallized film surface corrosion effect, making it conducive to overprinting.
At present, there are not many types of anti-crystallization agents, and the amount used should be controlled within 10%. If the ink film is crystallized and cannot be overprinted, transparent oil or 2% lye can be overprinted to erode the crystallized layer.

195. What is anti-gelling agent? How is its performance?
A: The anti-gelling agent is the collective name for making the inks have the function of eliminating the gelation. Gum inhibitors are generally light yellow pastes. The anti-gelling agent is transferred into the gelled ink. After grinding, the gelation phenomenon of the ink body can be eliminated or reduced.

196. What is the composition and function of paper?
A: The paper consists of plant fibers and accessories. The main source of plant fiber is papermaking pulp, which is the main material of paper and constitutes the basic framework of paper. The main role of paper auxiliary is to improve and improve the physical and mechanical properties of the paper so that it meets the requirements of use and achieves the specified quality. standard. Paper accessories include fillers, rubber compounds, dyes, etc.

197. What is the role of fillers?
A: Filler is a kind of white powder mineral, mainly used to improve the paper's opacity, smoothness, improve the paper's whiteness and elasticity, reduce the paper's moisture absorption, in order to maintain the paper size is relatively stable.

198. What is the role of rubber?
A: The rubber compound is added with some colloidal substances or film-forming substances that have liquid resistance and increased mechanical strength of the paper. The sizing method is divided into internal and surface sizing.

199. What is the role of dyes?
A: Dye refers to the trace amount of complementary color, bleaching, tinting, or whitening material added to the pulp during papermaking, mainly to improve the reflectivity of the paper to light, to achieve the required color, and to increase the appearance of the paper. .

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