Selection of adhesives commonly used in modern binding

Adhesive is one of the main materials for book binding. The choice of binder is directly related to the quality of the book book processing. When properly selected, the finished book book is firm and flat, otherwise it may cause serious quality problems.

Adhesive is a substance that firmly bonds two objects and is an indispensable material in binding. Some books, such as wireless binding books, are all connected together with adhesive. There are many problems in many areas of the country due to improper selection or unreasonable use of adhesives. For example, the hardcover book ring village is not sticky on three sides (flash), the book cover is warped unevenly, and the wireless binding book is missing pages The inequality of rubber bottoms and book backs is extremely serious. Unqualified products appear. The society reflects a lot and should be paid attention to by all parties.

Based on these circumstances, I will introduce the types, properties and use of the adhesive for the peers to use.

1. Synthetic resin adhesive

Synthetic resin, also known as artificial resin, is a resin formed by gathering or condensation polymerization of monomers. Synthetic resin adhesive is a widely used, convenient and wide variety of adhesive materials. The following are mainly used for book binding.

1. Polyvinyl acetate (PVAC) bonding material

Polyvinyl acetate is a polymer made by polymerizing vinyl acetate monomer. According to the different polymerization methods, it can be divided into two types: emulsion type and solution type. The binding type is emulsion type. Because of its milky white color, it is also called latex or white glue for a long time.

â‘ Properties of polyvinyl acetate

PVAC is a milky white viscous liquid with slight acidity. It is soluble in a variety of organic solvents and resistant to dilute acids and alkalis. It is not afraid of bites by worms and rats. It is not moldy and spoiled, and is harmless to humans. The cured adhesive layer of PVAC is a colorless transparent body, will not bring pollution to paper, etc., and is an aqueous solution, so it is easy to wash, and its viscosity can be adjusted at will. Easy to use. The PVAC adhesive layer has good toughness after drying, and the cutting will not damage the blade, which is very suitable for binding. This kind of glue has many advantages, but the disadvantage is that it has poor water resistance and poor heat resistance. However, as long as you pay attention to its performance, it will not be affected in any way. Common and popular synthetic resin bonding material.

â‘¡PVAC adhesive index

At present, the quality index requirements of PVAC adhesives produced in China are: milky white thick liquid, no obvious particles in the body: solid content 50% ± 2%: viscosity 1 ~ 2 microns; pH value 4 ~ 6: valid for one year It can be extended to a year and a half).

â‘¢ Use of PVAC adhesive

PVAC adhesives are widely used, especially suitable for the bonding of porous materials such as paper, fabric, cardboard, leather, wood, etc. Pay attention to the following points when using:

A. Before use, you can use cold water (not lower than 0 ℃) or hot water (not higher than 36 ℃) to prepare the adhesive with the required viscosity. The more water is added, the lower the viscosity. Stir evenly when adding water.

B. It can be used for single-sheet, double-page paper, pulp back, adhesive book back system, package cover (paperback), etc. It has good adhesion effect.

C. It can be mixed with flour paste, carboxymethyl cellulose, etc. to increase the consistency of the fluid and reduce the cost.

D. Pay attention to cold protection during winter use and heat protection during summer. Do not store and use the product below O ℃ and above 36 ℃ for a long period of time, otherwise the limbs will deteriorate and precipitate. For cold protection, appropriate amount of dibutyl phthalate can be added.

E. The remaining glue after use should pay attention to the sealing (especially after opening the barrel) not to contact with the air. It is best to pour some cold water on the glue surface to avoid the waste of dry knot hardness.

F. It is best not to use this glue for pasting book covers. Because PVAC is a water-soluble binder, the drying speed (same as rough paste) is slow, strong penetration, and not easy to shape. After pasting, the book cover will be deformed due to moisture penetration and delayed drying time. .

After G.PVAC adhesive is mixed with 504 glue, bonding PVA coating cover and ring backing paper has a good effect.

The drying of PVAC adhesive depends on the evaporation of water. The drying speed is directly related to the temperature and relative humidity. The drying speed is relatively slow: if it is used in the linkage production line, it needs to add drying equipment, such as far infrared, high-frequency medium heating, etc. The drying temperature should not be too high.

2. Polyvinyl alcohol (PVA) bonding material

Polyvinyl acid binder is a white flocculent or powdery polymer compound that can dissolve in water and is a colorless and transparent viscous liquid after hot melting.

â‘ Polyvinyl alcohol bonding performance

The performance of PVA is determined by the structure of polyvinyl acetate and the degree of alcoholysis. When the degree of alcoholysis reaches 99% -100%, a highly crystalline polymer can be obtained with excellent water resistance; when the degree of alcoholysis is 87% -89%, it is easily soluble in water; when the degree of alcoholysis decreases again, the The solubility of water is reduced again. PVA with a high degree of polymerization has a large molecular weight, good film-forming properties, high viscosity and strong viscosity, but poor water solubility. The degree of polymerization is divided into three categories: high, medium, and low, that is, 500 to 700 is a low degree of polymerization: 700 to 1500 is a medium degree of polymerization: 1500 to 2000 is a high degree of polymerization. For binding PVA adhesives, both the degree of polymerization and water solubility must be considered.

â‘¡Use of polyvinyl alcohol

When using PVA adhesive, add water and heat to melt it into a viscous liquid. Its usage and precautions are as follows:

A. According to the required viscosity, add appropriate amount of water into the glue and place it in a container to heat it into a uniform viscous liquid. When heating, use steam or water bath. Do not directly contact the heater. The heating temperature in the glue should not exceed 100. ℃, to prevent its deterioration.

B. The use temperature of PVA is 45 ℃ ± 10: it can be mixed with flour paste under appropriate temperature conditions.

C. PVA is a heating glue, water is not easy to penetrate, and it is slow to dry. It can be used for bonding cardboard, paper, fabric, etc. This glue can also be used for hardcover book cases.

Polyvinyl alcohol bonding material is cheap and has good bonding performance. It is a very commonly used bonding agent.

3. Hot melt victory (EVA)

Hot melt adhesive is a 100% soluble polymer that requires no solvent and no moisture. Hot melt is solid at normal temperature, and when heated and melted to a certain degree, it becomes a liquid with a certain viscosity: the hot melt adhesive after melting is a light brown translucent body.

â‘ The composition of hot melt adhesive.

The main component of hot-melt adhesive is EVA resin, that is, polyethylene and vinyl acetate polymerized at high temperature; then melted with rosin, glycerin, polymerized rosin, paraffin, etc. after high temperature, cooled and solidified into a blocky colloid, that is for binding Blocky or granular hot melt adhesive. The main component of hot-melt adhesive is EVA resin. Due to the difficulty of its polymerization and processing in China, imports are used instead.

â‘¡The performance of hot melt adhesive

EVA is a 100% solid glue, which turns into a fluid completely heated and melted by high temperature.

When heated to 80 ℃ ~ 100 ℃, the colloid slows down. With the increase of temperature, the flow gradually accelerates. When the temperature rises to 250 ℃, the colloid ages, the color becomes darker, the viscosity decreases, and the gel becomes clothing. EVA's colloid curing process is completed by cooling. It is a fast-curing bonding material with excellent performance. Its drying speed is unmatched by any bonding material.

â‘¢The use of hot melt adhesive

EVA can bond both porous and non-porous materials. The adhesive surface should not be too large, otherwise it will not be able to bond, because the curing time of this adhesive is only a dozen seconds at most. EVA is mainly used in the high-speed production of wireless binding line, can not be used for manual binding operations.

A. When using, the amount of glue should be stored in advance, and heated more than 2 hours in advance, so that it gradually becomes the required fluid.

B. The fluidity of the colloid can be controlled by temperature. When the viscosity is high (thick), the temperature can be lowered slightly. When the viscosity is low (thin), the temperature can be increased. For the one-time glue application on the glue binding machine, 150 ℃ ~ 180 ℃; the temperature of the second application (device with adhesive backing paper) is about 30 ℃ higher than the first application temperature, that is, the viscosity of the second application is absolutely Do not pull off the back sheet of the book that was stuck for the first time.

C. The curing time of hot melt adhesive is generally 7-13 seconds: the cooling time is generally about 30 seconds. In the linked production line, the cooling process is realized by extending the conveyor belt. In a certain period of time, it is necessary to ensure that the colloid has good conditions for cooling and drying, so as to ensure that the books are firmly bonded, beautiful and smooth.

D. The conditions for production using hot melt adhesives should be to ensure normal room temperature. Too low a room temperature will affect the curing time. The adhesive will be peeled off due to premature drying and poor adhesion (or inability to adhere) by the adhesive.

3. Paper-plastic composite bonding material

This material is a copolymer of acrylate and styrene, and its appearance is a milky white liquid. The colloid has good adhesion performance and the required viscosity and film elasticity. Paper-plastic composite adhesive uses water as a dispersion medium (aqueous solvent), non-flammable, non-toxic, harmless, and non-irritating odor. It is a water-soluble adhesive material that is easy to use and has a strong bonding ability.

This kind of adhesive is more widely used with the change of the binding material (such as PVC coated paper, laminated paper, plastic cover, etc. in the cover material). This adhesive must be used in the connection with the paper, especially the cover of the upper class material. The hard cover of the hardcover and the ring liner are glued. If the three sides are not sticky, you can use this glue to stick it.

Paper-plastic composite adhesive can be used for manual binding and machine binding. It is easy to operate, has high viscosity and firm bonding. This adhesive was mass-produced in the mid-1980s, with good results and fast popularity, and solved the quality problem of non-stick on three sides of the ring lining. [next]

2. Animal adhesive materials

The use of animal bonding materials has a long history in China. As early as more than 2,000 years ago, people used animal leather to add water and fire to make bran glue for the bonding of various objects. This glue is a bonding material obtained from the skin, intramuscular tissues and bones of animals treated with hot water or lime mortar. There are several types of animal bonding materials, including bone glue, gelatin and fish glue. Bone glue is commonly used in binding, and fish glue is very versatile from dried fish, so it is basically not used to make bonding material.

1. bone glue

Bone glue is one of the most widely used animal bonding materials. Its characteristics are: good adhesion performance, high strength, less moisture, fast drying, good adhesion stereotypes, low price, easy to use, especially suitable for adhesion and paste hardcover book cover, can get good results.

â‘  Performance of bone glue

The main component of animal gum is gelatin skin protein.

The one with low purity is called bone glue. Bone glue is a brittle, hard solidified body. Collagen is a protein that is insoluble in water. After treatment such as heating, collagen becomes another form of protein called gelatin, which is soluble in hot water and has adhesive properties.
The bone glue film is very strong and elastic after formation: but the bone glue is not resistant to water, and the water layer will expand the glue layer and lose the bonding strength: its corrosion resistance is also poor, too high temperature and excessive humidity will cause changes.

â‘¡Use of bone glue

When using bone glue, first soak the bone glue with equal or slightly more water (preferably hot water) for about 10 hours to soften the glue block, and then heat it to about 75 ° C to make it into glue. The ratio of glue to water should be based on the required viscosity, such as more water, low viscosity and dilute: add less water, the viscosity is high and thick. When hot glue is used, the temperature of the glue should not be too high. If the temperature exceeds 100 ° C, the viscosity will decrease due to molecular degradation, and the glue will age and deteriorate. Bone glue has a small amount of precipitation during use, so it is necessary to add a water well while stirring to adjust the viscosity and fluidity. When hot glue is used, the bath heat method must be used, and the container for storing glue should never be used for direct heating.

Bone glue must be kept at a certain temperature before it can be used. Therefore, when water needs to be added during use, the temperature of the added water and the colloid should be basically the same, and cold water should not be added. Because the bone glue must maintain a certain temperature (75 ℃ ± 10 ℃), after the cold water is added, the temperature of the glue will suddenly drop and the stickiness will appear, which will affect the bonding effect. When using bone glue, the glue application speed should be fast and even. Do not dunk too much glue at once to cause problems such as uneven glue layer, penetrating adhesive leakage and so on.

2. gelatin

The composition of gelatin is similar to bone gel, but the purity is higher and the colloid is transparent. The raw materials for making gelatin are high-quality fresh animal skins, scraps and bones. The melting temperature and coagulation temperature of gelatin are different from bone glue. Although the purity of gelatin is high, there are still some plasticizers. These plasticizers can absorb moisture from the air to prevent the adhesive layer from drying too much and becoming brittle.

Gelatin can be added with corresponding water before use, and it can be completely melted into the required glue solution at about 50 ℃. The commonly used glue temperature is 40 ℃ ~ 70 ℃, and it can still be used if it is not lower than 30 ℃. This kind of glue is better to use than bone glue, and has the same characteristics as bone glue. It is a high-quality bonding material in animal cavity, but the price is not suitable for large quantities, otherwise it will increase the cost.

A. In order to prevent the animal adhesive layer from becoming brittle after drying, an appropriate amount of glycerin can be added. Make the film have a certain flexibility.

B. In order to prevent the glue from getting moldy and deteriorated (especially when the temperature is high in summer), an appropriate amount of preservatives, such as carbolic acid, can be added to the glue.

C. In order to prevent the gum color from aggravating, some whitening agents, such as titanium dioxide, etc. may be blended in an appropriate amount.

D. In order to improve the drying speed of the adhesive film at room temperature, a small amount of urea can be added.

E. When gluing the shell with the machine, bubbles are likely to appear in the glue solution, resulting in uneven coating. For this purpose, a small amount of terpene alcohol or silicone liquid, tributyl phosphate, etc. can be added.

The above additives must be mixed evenly before they are added to the glue.

A large part of the quality problems of bookbinding are caused by improper use or selection of binding materials. Therefore, understanding the types, properties and uses of commonly used binding materials and improving the understanding of binding materials is an important aspect of ensuring product quality. .

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