· Performance characteristics Synthetic paper is a very durable, dimensionally stable waterproof paper. It is made from polypropylene (PP) and inorganic fillers as the main raw material, not paper made from natural fibers, so synthetic paper has plastic and The characteristics of fiber paper. Compared with high-grade fiber paper, synthetic paper has high surface strength, excellent smoothness and excellent whiteness. As a substrate material, it has been widely used in offset printing, letterpress printing and other fields, mainly used to print pictures, pictures, Calendars and other advanced fine print, food, tobacco, cosmetics and other packaging, as well as securities, in-mold labels and other special printed matter.
Synthetic paper is a non-absorbent substrate material, so the offset printing ink used for synthetic paper has particularly good drying performance and should exceed the general offset ink; the printing process requires no backside stain, sticking, etc.; the ink is used. The solvent tends to cause swelling and warping of the synthetic paper, so only a small amount of solvent can be used in the ink; the ink has good adhesion to the substrate material, and has excellent abrasion resistance; but also has high color concentration and resistance Features such as good water performance.
Synthetic paper offset printing inks have been specially formulated to be a single oxidative polymerization drying ink. The current maximum printing speed is up to 10,000 sheets/hour (adjustable according to the thickness of the paper and the size of the printed graphics area). The environment-friendly synthetic paper offset printing ink described in this article consists of soybean oil-based oxidative polymerization-drying resin binders, pigments and fillers, anti-friction agents, driers, anti-skinning agents, and a small amount of petroleum solvents, and its harmful heavy metal elements and volatilization. Organic organic compounds (VOCs) are in compliance with international standards (ISO) and industrial developed country standards. The average composition of the ink is as follows:
Rosin Modified Alkylphenol Phenolic Resin 25～26%
Linseed oil/isophthalic acid alkyd 9~10%
Refined soybean oil 23 to 24%
Refined tung oil 7～8%
High boiling point petroleum solvent 3～4%
Pigments 20 to 21%
Filler 2.5 to 3.0%
Auxiliaries (anti-friction agents, driers, anti-skin agents) 6.5 to 7.0%
Total: 100%
Manufacturing Example 1. Rosin modified alkylphenol phenolic resin, linseed oil/isophthalic acid alkyd resin, soybean oil, tung oil, and organoaluminum gel (aluminum chelate) etc. are used in the production of the binder for the ink binder. . Among them, rosin-modified alkylphenol phenolic resins have characteristics of high viscosity, high solubility, high softening point, etc., and can impart fast drying, high gloss and adhesion to inks; linseed oil/isophthalic acid alkyd resin has fast Dry, high gloss and wetting and dispersing properties of pigments (fill materials); soybean oil, although belonging to semi-dry oil (iodine value 120-140gI2/100g), polymer oil produced by copolymerization with 25% of tung oil has similar dryness. The drying performance of oil linseed oil; organic aluminum gelling agent KETALIN-4F can increase the viscosity of the prepared linking material by 1 to 1.5 times, but the viscosity does not increase substantially, and the drying and fixation time of the ink can be shortened, and the glossiness and water resistance can be improved. Dot reproducibility. The recipe examples are shown in Table 1.
Table 1. Binder Formula Example Raw Material Specification Matching %
Rosin modified octylphenol phenolic resin with an acid value of 16 to 24 mgKOH/g, viscosity of 2200 to 2800 mPa·s/35°C 38
Flax oil/isophthalic acid alkyd resin acid value ≤18mgKOH/g, viscosity 4000～6000mPa·s/35°C 14
Refined soybean oil (a) First grade, iodine value 120 ~ 140gI2/100g 28
Refined tung oil level 10
High boiling point oil solvent distillation range 270～310°C, aromatics ≤ 1% 5
Refined soybean oil (II) First grade, iodine value 120～140gI2/100g 4
Organic aluminum gel KETALIN-4F aluminum content 5.0 ~ 5.5% 1.0 ~ 1.2
Total 100
Operation method:
(1) The purified soybean oil (I), purified tung oil and rosin-modified octylphenol phenolic resin are added into the reaction kettle according to the formula, heated up and the liquid surface is protected by CO2 or N2, and stirring is started when the temperature reaches 180°C.
(2) continue to heat up, about 2 hours until the temperature reaches 250 °C, at 250 ~ 255 °C stirring for 1 hour.
(3) Add linseed oil/isophthalic acid alkyd resin and keep it at 220-225°C for 30 minutes. At this time, stop CO2 or N2 protection, stop heat preservation, add high boiling point petroleum solvent, and stir for 20-30 minutes.
(4) When the material temperature is 160° C., the organic aluminum gelling agent KETALIN-4F diluted in advance with purified soybean oil is added, heated to 180° C., and kept at 175-180° C. for 30-40 minutes.
(5) The sample is measured for viscosity, and immediately after filtration, the material is filtered and placed in a storage container for use.
Technical indicators:
Viscosity 14000～18000mPa·s/35°C
Viscosity (400rpm, 32°C) 8 to 12
Appearance transparent, no mechanical impurities
2. Environment-friendly Synthetic Paper Offset Printing Ink The above-mentioned oxidative polymerization drying type linking material is used in the formulation of environment-friendly synthetic paper offset printing ink, which has characteristics such as fast drying, light and adhesion, and good water resistance; it is slightly higher in the amount of pigment used. In general offset printing inks, in order to improve the tinting strength; use of polyethylene microcrystalline wax and PTFE microcrystalline wax, can significantly improve the anti-friction performance of the ink film; In addition to cobalt octoate, manganese iso-octanoate in the drier , also added to help drier zirconium octoate, can improve the efficiency of cobalt and manganese driers; in addition to butanal oxime as an anti-skinning agent, so that the ink is not easy to oxidation in the thick layer crust, and after printing When it is a thin layer, it can quickly restore the drying performance. In the ink formulation, only 3 to 4% of petroleum solvent is used to adjust the viscosity. When the ink is dried and filmed, it can also act as a plasticizer, making the ink film flexible. See Table 2 for examples of ink formulations.
Table 2. Eco-friendly Synthetic Paper Offset Printing Ink Formula Example Material Name Specification Magenta Yellow Sky Blue Black Ink Viscosity 14000～18000mPa·s/35°C 66 71 70 62
Magenta 6B PR 57:1 21
Benzidine Yellow GTNS PY 12 6
Benzidine Yellow GR PY 13 10
Phthalocyanine Blue BGS PB 15:3 18
Transparent colloidal calcium carbonate 3.5 4 3.5
Lightweight Cyan original R 1
501 iron salt potassium salt, red light 3
Light blue light AG red light 5
High pigment carbon black 8
Furnace carbon black W – 4S 10
Polyethylene microcrystalline wax 2 2.5 2 1
PTFE microcrystalline wax 1 1 1 1
Cobalt iso-octoate Co content 8%, ink 2 2 2 3
Manganese octoate Mn 7%, ink 1 1 1 1
12% zirconium isooctanoate, 0.4 0.4 0.3 0.5 for ink
Butyral aldehyde content 99% 0.1 0.1 0.2
Low Viscosity Polymer Oil Soybean Oil/Tung Oil = 3/1, Viscosity 80～120mPa·s/35°C 3 2 2 4.5
Total 100
According to the formula of Table 2, the ink binder, pigment, filler and wax powder are fully stirred and pre-dispersed, ground and dispersed on a three-roll mill or bead mill, and after the fineness reaches the required level, a low-viscosity polymer is added to adjust the viscosity and Ink, the final addition of cobalt, manganese, zirconium driers and anti-skinning agent butyraldehyde oxime in the machine evenly mixed, after the indicators are qualified, the filter filling into the packaging container.
Application Notes Eco-friendly Synthetic Paper Offset Printing Ink is not only suitable for monochrome, two-color, four-color offset printing presses, but it can also be used on letterpress printing machines. In addition to synthetic paper, non-absorbent substrates such as gold, iron and aluminum foils can also be printed.
When printing with the above ink, note the following:
(1) Prevent the static electricity generated by hand rubbing when the synthetic paper is taken, cut, and stacked, and reduce the adhesion of ink, so be sure to wear non-chemical fiber gloves.
(2) Synthetic paper needs to be stored in the printing shop for 48 hours before printing to suit the workshop environment.
(3) Since the synthetic paper does not absorb water, the amount of plate fountain solution must be adjusted to be as small as possible to maintain the ink-water balance. The pH of the fountain solution should be maintained at 5.5-6.0, the ambient temperature should be controlled at about 25°C, and 15% to 30% alcohol should be added to the fountain solution.
(4) Due to the slight elasticity of the synthetic paper, the printing pressure should be increased as compared with the ordinary paper, and printed with a four-color offset printing machine using an alcohol fountain solution.
(5) When printing on both sides of the paper, the less side of the text is printed first, and the dusting is as uniform and as small as possible.
(6) If the printing process is stopped for 2 to 3 hours, a layer of anti-skinning agent (butyraldehyde oxime, butanone oxime) shall be sprayed on the ink fountain, roller surface and printing plate to prevent the oxidized crust of the ink from being re-booted. Printing failure.
(7) When the drying property of the ink is insufficient, a desiccant such as erythromycin oil may be appropriately added to adjust.
(8) The synthetic paper prints on the delivery table should be stacked with separators. The stack height between the partitions should not exceed 15cm.
(9) Do not move or subject the paper stack to vibration before the ink layer is completely dried, so as not to make the printed material that has not been completely dried back rubbed due to friction or pressure on the ink film.
(10) The drying time varies depending on the type of printing machine, the thickness of the ink layer, and the density of the printing plate graphic color. Generally, the surface of the printing product is dry after 4 to 5 hours, and subsequent printing can be performed. After 12 to 24 hours, the printing product is completely Dry, can cut processing.