462. What is binding material for binding? There are several bonding mechanisms?
Answer: The binding material used for bookbinding refers to a substance with excellent adhesive properties used when binding books. There are three kinds of adhesion mechanisms, namely, osmotic adhesion, attracting adhesion and semi-permeable bonding.
463. What is penetration adhesion?
A: Penetrating adhesion is the penetration of the binder into the micropores on the surface of the two bonded materials, and the bonded materials are bound together by mechanical force. This kind of bonding method is only effective for the adhered materials whose surface is able to penetrate the adhesive, and requires the adhesive liquid to have good fluidity, can penetrate into the pores (fiber holes) on the surface of the adhered material, and can be dried and cured. Like a myriad of small hooks, the two bonded materials are firmly hooked together. Paper, cardboard, fabric, etc. are all porous materials. The binding method used for binding is mainly osmotic bonding.
464. What is attracting adhesion?
A: Attracting adhesion is based on the attraction between the binder and the molecules of the adhered substance, which bonds the two objects together. Suction-type adhesively bonded objects have no permeation capability, such as glass, porcelain, and plastic, and rely on the adhesive's own strength, strong adhesive force, and the attracting ability of polymer molecules in the chain structure to attract and firmly bond the two objects. It does not require a certain amount of pressure to penetrate and bond.
465. What is semi-permeable cement?
A: Semi-permeable cementation means that one of the two bonded materials has permeation capacity (that is, the surface has micropores), and the other has no permeation capacity (such as plastic, glass, etc.). It is necessary to bond the two together, such as paper and plastic. Bonding of films, bonding of paper and coating materials, etc. The adhesive used for this bond must have both the strength to attract the bond and the liquid flowability to penetrate and bond in order to achieve a good bond effect.
466. What are the requirements for binding adhesives?
A: (1) Wettability requirements: Wettability refers to the degree of wetting of an adhesive to a bonded object. When the adhesive is used, it must be applied to each part where the adhesive needs to be bonded in order to achieve the adhesive requirement. If the adhered object cannot completely wet the adhered part, it will cause the two adhesive surfaces to be in poor contact, and the adhesive will not be firm, cause bubbles, separation, etc., resulting in defective products. Therefore, the adhesive material must be well-oiled during use. Wet.
(2) Fluidity requirements: The fluidity of the adhesive refers to the fluidity of the adhesive in use. According to the texture of the material to be bonded and other specific conditions to choose different fluidity of the adhesive, in general, the better the fluidity of the adhesive, the thinner the adhesive, the lower the viscosity and adhesive strength; adhesive fluidity, viscosity With a high bonding strength (except for hot-melt adhesives). Regardless of fluidity, the adhesive itself must be uniform and moderate.
(3) Viscosity requirements: Viscosity generally refers to the degree of thickening of the adhesive (with the exception of hot-melt adhesives). Viscosity reaction adhesive flow properties. In actual use, no matter what type of binder, the viscosity value should be controlled within a certain range, and the viscosity value cannot be arbitrarily increased due to poor adhesion. It depends on the properties of the bonded object, the type and performance of the binder, and the binder. Viscosity is properly controlled to achieve good adhesion.
(4) Viscosity requirements: The stickiness of adhesive refers to the firm performance of two objects after they are bonded. The adhesiveness mainly depends on the cohesive strength of the adhesive. The cohesive strength of the adhesive can ensure that the adhered material is not adhered. Will fall off and separate. The cohesive strength must be determined according to the needs of the adhesive, and the cohesive strength is not good enough. The coating will be uneven and unsmooth. The paper will wrinkle and warp after bonding. The cohesive strength is too small. Can't bond firmly.
(5) Bonding strength requirements: Bonding strength is an important standard for bonding materials, that is, the degree of bonding. The bond strength can be tested by the following simple method: If the cover is coated with a coating material or fabric and paperboard, the surface of the paperboard to be bonded can also be peeled off when the cover material is peeled off after a certain period of time after the adhesive is dry. In the next layer, the book and the cover are dried and cannot be peeled off or peeled off, and the other layer is still stuck on the top.
(6) The amount of binder required: The amount of binder is the thickness applied to the adhered material. When the wettability, fluidity, strength, and viscosity of the adhesive meet the requirements, the amount of the adhesive becomes the main link. Therefore, it is required that: (1) The adhesive should be applied less evenly and evenly. Since the strength and fluidity of the adhesive are all acceptable, as long as the applied adhesive layer is thin and uniform, it can completely achieve the effect of firm bonding. Thin and uniform is far thicker than uneven. The smear is much better and reduces the amount of binder. 2 When the viscosity is not enough, do not make up for it with additional amount. Re-adjust or replace the adhesive. Also, do not disperse the adhesive after it has been deposited in large quantities to save time. This will result in too much moisture permeation, spillage, or inconsistent application. Adhesive adhesive books may appear, and the adhesiveness of the book may deteriorate. This may affect the quality of the book.
(7) Color requirements: The color of the adhesive directly affects the appearance of the book, so the adhesive should be transparent, translucent, white, and white. However, because some hot-melt adhesives need to be heated and heat-melted, such as modern EVA hot-melt adhesives, they must be heated according to the standard of technical parameters when they are used. They cannot be easily heated, otherwise the adhesive temperature is too high or turns round. Heating, long-term cleaning, etc., will make the adhesive aging, darker color, affect the quality of book appearance, and even cause combustion.
(to be continued)