Whiteboard paper is a kind of hard cardboard with a large thickness, so it is also called white paperboard and it is a higher grade in cardboard. Whiteboard paper is made up of a surface layer, a core layer and a bottom layer. Its packaging form is flat paper. There are two types of whiteboard paper, one-sided and two-sided, and double-sided whiteboard paper is also called white cardboard. The main use of single-sided white paper in packaging and printing, single-sided white paper according to the surface layer, there are two categories of ordinary and paint; according to the underlying different gray and white two; ordinary white paper in accordance with the different quantitative, commonly used There are four kinds of 300g/m2 to 450g/m2.
The surface layer of the whiteboard paper is made of 100% bleached chemical wood pulp, or bleach bleached pulp is used to make the surface of the whiteboard paper, and an appropriate amount of whitening agent is added. The core layer is manufactured by using mechanical pulp or adding waste pulp, reed pulp, and straw pulp. The bottom layer is made of waste pulp, and the amount is filled and sizing.
The surface layer of whiteboard paper is bleached with chemical wood pulp, a certain proportion of filler and rubber compound, and after multi-roll calendering, it has good whiteness, high smoothness and surface strength, and has certain water resistance and flexibility. Small, moderately absorbent and relatively uniform. The thickness of the white paper is large, the fibrous tissue is uniform, the paper is tight, strong, opaque, and the mechanical properties such as tensile strength and folding resistance are high.
Whiteboard paper has a high moisture content, poor core layer and bottom layer water resistance, and high stretchability.
In the printing process, pay special attention to:
(1) The thickness of the whiteboard paper, and the thickness of the whiteboard paper with different basis weights, are also different. This factor must be taken into account when adjusting the printing pressure and the thickness of the drum liner.
(2) Adjust the gap between the front gauge and the feeder iron table.
(3) Adjust the grip force of the gripper properly.
Five aluminum foil paper
The unique charm and novel printing effect of aluminum foil packaging make aluminum foil printing become the mainstream of high-end products. Aluminum foil belongs to the specialty paper category. It is similar to the printing suitability of glass cardboard and the issues that are noticed in printing.
(a) The basic concepts of aluminum foil
Aluminum foil, commonly known as "gold (silver) cardboard, gold foil, metal foil." The essence of the title “steel fine paper, steel paper, aluminum paper†is aluminum foil.
The so-called foil in the metal material refers to the metal sheet after special processing. The thickness of this kind of sheet is called 0.2mm or less, because the metal material used in foil making is different, and its properties are shown. Gold is added in front of the foil word. , silver, tin, nickel, aluminum, etc. are shown differently.
There are two methods for producing aluminum foil: one is a composite method in which aluminum foil and paper are adhered and rolled together, and the other is a vacuum aluminum plating method in which aluminum is coated on the paper surface. However, no matter which way the aluminum foil is made, the surface layer is aluminum foil, and the paper is only its lining material.
(b) Printability of aluminum foil
The printability of aluminum foil is special because it is a composite of aluminum foil and paper. Its surface layer of aluminum foil or aluminum film has a metallic luster, a tough texture, and a smooth surface. In the printing process, the surface properties of the aluminum foil are directly related to the printability of the printing press, ink, and the like. Therefore, relatively speaking, the printability of aluminum foil, in fact, the printability of aluminum foil, the specific performance in the following points:
(1) The surface strength of aluminum foil is very high, it can adapt to the speed of high-speed printing presses, and it can also withstand the tension generated by the viscosity of ink, and has good adaptability to improve production efficiency and stabilize printing quality.
(2) The smoothness of aluminum foil is high, which is conducive to the transfer of ink. The printed ink film is flat, clean, graphic, and clear.
(3) The aluminum foil has a tight structure, no voids, and its surface is similar to the mirror effect. Therefore, it does not have the adsorption properties like paper.
(4) The curling of aluminum foil, which is caused by the difference in physical properties between the material structures. Aluminum foil has high strength, high density, good stability, and is not easy to expand. The paper has low strength, relatively small density, poor stability, and is easy to expand and contract. The properties of aluminum foil and paper are very different. These two materials, which are different in nature, are compounded by latent curling factors. However, this is only its intrinsic factor. Generally, it does not curl when it is suitable for its conditions. However, when the ambient temperature and humidity change greatly, aluminum foil curl will be induced.
(III) Points for Printing on Aluminum Foil
The difficulties in printing aluminum foil on offset presses are mainly due to the poor dryness and stickiness of printed products. For this reason, special attention should be paid to aluminum foil in offset printing:
(1) Control the environment temperature and humidity.
(2) When selecting the ink, it should be noted that the drying mechanism must be mainly oxidized conjunctiva. It is not easy to dry on the ink roller, but it can be quickly dried on the aluminum foil paper. Existing aluminum foil ink.
(3) The printing ink should not be too thick. Because the surface of the aluminum foil is smooth and the adsorption force is poor, it is necessary to reduce the adsorption force between the blanket and the ink by increasing the fluidity of the ink so that it can be smoothly transferred to the aluminum foil under the proper pressure.
(4) Keep the minimum liquid supply. Aluminum foil is not good at absorbing ink at the same time, it is also not good at absorbing wetting fluid. For this reason, it is possible to minimize the amount of liquid to be supplied without the printing plate being dirty.
(5) Take anti-sticking measures:
a. Increase the amount of desiccant by adding and releasing b. Add and release the separator. Put a paper separator every 50-100 sheets to make the printed sheets layered, which can effectively prevent sticky. Because the difficulty of printing aluminum foil is often difficult to overcome, UV offset printing is commonly used.
Six embossed cover paper
Embossed cover paper belongs to the specialty paper category and is a kind of decorative paper for books, magazines, books, and covers. There is a pattern on the surface of the paper that is not very noticeable. The colors are white, gray, green, beige, pink, and other colors. According to the different materials used, they are divided into three levels: A, B, and C. Level A is used for printing and binding of books and magazine covers, and Levels B and C can be used for general magazines and covers of this book. Of course, embossed cover paper is by no means limited to the printed book cover.
Embossed cover paper has a high mechanical strength, wear-resistant folding, not easily damaged, has good dimensional stability and durability, paper color is bright and smooth. Its paper weight is generally 120-230g/m2. Most of the embossed cover paper is a flat sheet of paper. The smoothness is not assessed, and the color paper is not evaluated for whiteness.
Embossed cover paper should pay attention in the printing process:
(1) According to the characteristics of the printed matter to be printed and the type of offset printing machine used, choose the embossed cover book.
(2) Carefully adjust the ink's suitability during the printing process to control and reduce the amount of wetting fluid to prevent the powder from falling and the failure of hair loss.
(3) When printing, the printing pressure may be appropriately increased, or inks with greater fluidity and more wettability may be used, so as to compensate for the fact that the imprints due to the unevenness of the paper are not true to some extent.
(4) Since the embossed cover paper has a pattern on its surface, its acceptability to the ink is poor. In contrast, the transfer rate is relatively small. Therefore, it is necessary to constantly observe the change in the ink color and make corresponding adjustments during printing.
Seven map paper
Map paper mainly prints maps, topographic maps, hydrogeological maps, tourist maps, etc. Its technical specifications are basically similar to offset paper, but have higher requirements in the following areas:
(1) The mechanical strength is high, and in particular, the folding resistance is required to fold back and forth several times without breaking. For this reason, part of the bleached pulp or pulp should be added during pulping.
(2) Smoothness should be high, reaching 80-140s to print or draw thin lines on paper.
(3) Good dimensional stability, close to vertical and horizontal expansion ratio, sizing degree> 1.25mm, small deformation when wet.
(4) Light fastness, less dust, so as not to be confused with the symbols on the map.
(5) The ration of map paper is generally 55, 100, 120, and 140g/m2. If printed maps are used, there is a higher requirement for the paper's water resistance and wet strength.