On the adhesive materials of the most popular book

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Adhesive materials for books and periodicals (Part 1)

I. forms of book and periodical bonding

under certain conditions, substances that can bond the same or different types of solid materials together through the interface are called adhesives, which are a kind of bonding materials

the method of connecting the surfaces of two solid materials through the adhesive force is called bonding. In book binding, bonding is one of the important methods to connect single pages into books, which can even lead the development of the industry. Therefore, adhesive material is an important material in book binding production

in book binding, there are two forms of bonding: end face bonding and plane bonding. The connection between the lining page, insert page, table, etc. and the book post, including the lining strip, the cover, the back of the hardcover book block, the production of the book case and the book case are all plane bonding. Wireless adhesive binding and hot-melt binding belong to end face bonding. The plane bonding is overlapping, and the contact area is relatively large, so it is relatively firm. End face bonding is to make the end faces of the paper bond with each other by infiltrating the adhesive into the page. According to the penetration depth of the adhesive between the papers and the thickness of the formed adhesive film, the bonding rate is also the same

II. Requirements for binding adhesives

in book binding, the bonded objects are mainly fiber materials (paper, paperboard, cloth, etc.); If books and periodicals are covered with film, the bonded object is the bonding between fiber materials and some plastic film layers. The binding fastness directly affects the binding quality of books and periodicals. It not only depends on the structure and properties of the adhesive and the surface of the bonded object, but also has a close relationship with the operating conditions of the bonding process

therefore, the selection of adhesive should not only consider the properties of the surface of the object to be adhered, but also be based on the binding process and the requirements in the use process

1. Requirements of binding process for adhesives

(1) liquidity. The adhesive used for book binding must have good fluidity, so that the adhesive liquid can fill the micropores on the surface of the adhered object, and can fully and truly contact with the uneven surface of the adhered object during bonding

(2) wettability. In order to obtain the ideal bonding effect, the adhesive should be well coated on the surface of the object to be bonded, and the contact area with the surface of the object to be bonded should be as large as possible. In other words, only when the adhesive fully moistens the surface of the object to be adhered, and then loses fluidity and generates strong cohesion, can it produce a good bonding effect. Therefore, wetting is the prerequisite for bonding. Only when the surface tension of the liquid is less than or equal to the surface tension of the solid can the liquid be completely wetted on the solid surface. Therefore, the surface tension of the adhesive should be as small as possible. In this case, the contact angle between the liquid adhesive and the surface of the object to be adhered is less than 90, so that the surface of the object to be adhered can be wetted

(3) viscosity. In order to obtain a good bonding effect, in addition to the full wetting and penetration of the adhesive on the surface of the bonded object, it must also have a bonding strength. The adhesive strength is determined by the cohesion of the adhesive itself and the adhesion between the adhesive and the bonded object. The viscosity of the adhesive, in addition to directly affecting the wetting and penetration speed of the adhesive on the surface of the object to be adhered, is also the main factor affecting the bonding strength

adhesives with high viscosity have high solid content, low moisture content, high cohesion and high bonding strength. However, the adhesive has a small fluidity and is not easy to penetrate, so it is mostly used for bonded objects with relatively small bonding area, such as adhesive sheets, illustrations, covers, etc

the adhesive with low viscosity has good fluidity. It is easy to fill all the pores on the surface of the bonded object and increase the bonding surface area when brushing. However, it has low solid content, low cohesion and low bonding strength. Most of the brushed adhesive liquid is absorbed by the bonded object, and the remaining adhesive materials are not enough to form a strong bonding film on the bonded surface

in binding production, water-soluble adhesives are mostly used. With the continuous volatilization of water, the viscosity of adhesives is also rising. For the hot-melt adhesive, the change of temperature also leads to the change of adhesive viscosity, which greatly affects the bonding performance of the adhesive. In order to ensure the fastness of bonding, the viscosity of the adhesive must be controlled when it is prepared and used according to the type and performance of the object to be bonded and the adhesive

(4) gluing time and setting time. The binding adhesive shall have certain gluing time limit and setting time. The gluing time limit refers to the time that the adhesive will not lose its viscosity after it is applied to the surface of the object to be glued. This duration should be the time necessary to complete a certain binding work. Only in this way can we ensure that the two bonded objects such as felt textile fiber and textile bold stick firmly at the required position before the adhesive solidifies

(5) during the bonding process of the bonded object, the performance of the adhesive material must be stable

2. Requirements for the use of adhesives

(1) the aging period of the adhesive shall be longer than the service life of the designed publication to ensure the normal use of the publication

(2) in order to prevent the adhered object containing common fault 2: cellulose from damage, discoloration and fading of printed text, the adhesive shall be neutral or weak acid

(3) the adhesive shall be colorless and transparent

(4) the adhesive shall have strong bonding force. To stick the bonded object, the strength of the adhesive layer shall be higher than or equal to the strength of the bonded object

(5) the adhesive layer shall have certain flexibility to ensure that the adhesive film will not be damaged during the further processing of semi-finished products and the reading, storage and transportation of books

(6) the adhesive shall be tasteless, non-toxic, non moldy, non moth eaten, non rat bite, non flammable and cheap

the above are common requirements for adhesives. When a specific process is completed, adhesives with appropriate performance should be selected according to the characteristics of the process. For example: ① for bonding single sheets of paper such as ring liners, inserts, tables, etc., due to the small bonding area and firm bonding, a high viscosity adhesive is required. ② The glue used to bond the back of the book should ensure that the book is firmly bonded at the crease, so that the glue film at the bonding place has a certain flexibility, and can keep the back of the book arched after opening the book. Therefore, the adhesive with appropriate performance should be selected according to the type of printing paper. ③ When binding with wireless adhesive, the adhesive shall have appropriate viscosity. When the viscosity of the wave liquid is too high, its fluidity becomes poor, the permeability is not good, the glue liquid is not easy to fill the pores on the bonded surface, and the bonding of the pages is not firm; When the viscosity of the adhesive solution is too low, the adhesive film with sufficient thickness cannot be obtained during bonding. ④ In the process of wrapping

the cover and finishing the book, because the glue brushing and wrapping the cover or the book case are not the same process, in order to catch up with the beat of the linkage production line and facilitate correction, and to make the cover material or the book case and the back slide relatively, the adhesive with long setting time and large viscosity should be used

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