Choose the right substrate for better results

(Take stock of your stock selection process for better)

In the printing process, the choice of paper (weight, thickness, coated and uncoated, texture, silk, porosity, transparency, color) plays a crucial role in the binding plant. This article will discuss the impact of different paper on post-press processing.

The impact of coating and bindery coating on the binding process is enormous. The complete binding process includes gluing, creasing, folding and some special binding steps. In addition, coated paper has some complicated factors that affect the binding process, such as the coated paper surface covered with a thick ink film and protective coating, such as coating oil and UV coating.

Bonding coated paper is very difficult because the hot melt does not adhere well to the paper. But using PUR adhesive can solve this problem. (You can also bind the book with a thread and then stick it on the book cover.)

Although the process of binding the coating paper with a perfect binding machine is fine, it is still important to ensure that all inks, coatings, and other coatings are kept away from the gluing area in the book. Previously, if the texture of a job's substrate is not delicate, there are several types of paper mixed, the ink coverage is relatively thick, there is a spread content, and the coating layer of the substrate is thicker, then it is almost impossible to use glue binding. Techniques for binding, but now it is possible to bind it with Otabind technology while using PUR adhesive.

In the actual binding process, moisture from the adhesive is used to wet the paper in the book, but often the clay-coated substrate is creped. Therefore, coated paper is rarely used for hardback book liners. The body of a book made of coated paper is also more complicated and very careful during the production process.

Professional post-processing In addition to binding problems, if the job also requires other post-processing operations, we must consider what kind of paper is suitable, such as film, UV coating, bronzing, embossing, and die cutting. Some people think that the film is relatively easy, and the film should be well attached to any type of paper and board, as well as to the fabric. Lighter (thinner) paper tends to curl when film is applied, and heavier paper (thicker) coats better. Because the diaphragm cannot make good contact with the pits of non-painted or multi-textured substrates, it does not adhere well.

When laminating coated paper, remember that no wax coating works best. Other varnish effects are also good, but also provide acceptable adhesiveness, but the adhesion is not very tight. In addition, no matter what kind of coating oil is used, do not use dusting, because it generates traps under the film to produce haze.

In addition, metal ink adhesion is not good, must use a kind of add glue to strengthen adhesiveness.

Materials coated with clay or enamel are best suited for UV coating, while non-coated paper will yellow and absorb paint, reducing the gloss of the print. Material below 60 grams coated with UV will curl and break when folded.

Other materials with a coated surface, such as cardboard and vinyl films, can also be combined with UV coatings. Paper coated with chromium can be well received with UV coating, but the paper will yellow.

Paper porosity is another factor considering UV coatings. High-pored paper will absorb too much UV paint too much and will not cure and dry. As a result, the gloss becomes lower and the abrasion resistance decreases. Conversely, paper with less porosity will first give a deceptive sensation of absorption, but if the coating is scratched, the coating will completely fall off. This phenomenon is called shelling and is caused by poor coating, insufficient adhesiveness of the paper, and poor paper grade.

The pH of the paper also needs to be considered. Acceptable pH values ​​range from 5.5 to 8. Above this range, the adhesion is lost, and a pH below 5.5 results in slower drying of the ink. If you do not know the specific PH value of the substrate, call your paper supplier or ask your binder to make a test report.

Make the prints glossy When you start the foiling process, the coated paper can make the foil really shiny, but it will also absorb some of the brightness of the foil. Instead of coated paper, having a heavier textured texture is more suitable for embossing with a metal foil because embossing can smooth the surface of the paper on the foiled area where the foil is desired.

Also, avoid bronzing on varnishes that contain wax or silicon. Metal foils are prone to bulging or blistering due to the high temperatures in the bronzing process.

Also note that proper dynamic (surface tension) levels are important in the UV coating and hot stamping process.

In the embossing process, the use of paper substrates is particularly important. Softer paper substrates are easier to emboss. Coated papers are best for showing details, but if the pressed bump height is relatively large (a simple horizontal die depth can be as small as 0.006 up to 0.024), non-coated paper may help to avoid breakage.

For deep-embossing embossing that does not require much detail, use coarse-textured or long-fiber uncoated paper. In order to reduce the fibers in the creases, the stamp is made beveled, allowing the edges of the sheet to be further stretched.

In the die-cutting process, the paper substrate is not too strict, and most substrates such as paint, non-coating, pattern, corrugated, and polymer can be die-cut. The thickness of the substrate depends on the process required for the job.