The composition of hot melt adhesive is mainly composed of basic resin, tackifier and viscosity regulator. Hot melt adhesive product category is classified according to the basic resin, the type of basic resin roughly EVA, TPU, PES, PA, PO, etc., the Chinese chemical name of ethylene/vinyl acetate copolymer respectively, thermoplastic polyurethane, polyester, polyamide, polyolefin, according to different types of these basic resin, hot melt adhesive can be divided into EVA hot melt adhesive, TPU hot melt adhesive, PES hot melt adhesive, PA hot melt adhesive, PO hot melt adhesive.

Ingredients:

1. Basic resin

The basic resin of hot melt adhesive - resin is ethylene and vinyl acetate copolymerization under high temperature and high pressure, resin is the main component of making hot melt adhesive, according to the required ratio when preparation, generally account for 40% ~ 60% of hot melt adhesive. The proportion of basic resin determines the basic properties of hot melt adhesive, such as adhesive bonding ability, melting temperature and the selection and preparation of additives, are different with the proportion of basic resin.

2. Reinforced adhesion agent

Adhesive is one of the main additives of hot melt adhesive, if only by the basic resin, only at a certain temperature melting with bonding force, once the temperature drops, it will bond is not firm, or even lose the bonding ability, it is difficult to wet and permeate the paper, can not achieve the ideal bonding effect. Adding an appropriate amount of adhesive in EVA hot melt adhesive can also improve the fluidity of colloidal, in order to enhance the wetting and penetration ability of colloidal to be sticky, improve bonding strength, to meet the needs of books on bonding strength. Adhesives generally use rosin substances and terpene resin, the proportion is generally between 15% ~ 20%.

3. Viscosity regulator

Viscosity regulator is also one of the main additives of hot melt adhesive, its role is to reduce melt viscosity, increase fluidity, wettability, adjust the solidification rate, in order to achieve fast bonding firm purpose. Without the addition of viscosity regulator, the colloidal viscosity will be too large, not easy to flow, difficult to coating, not easy to penetrate into the pages of the book, the pages of the book will not be able to bond firmly.

In the selection of viscosity regulator should choose the substance with low melting point, such as the commonly used paraffin, its softening point between 65 ~ 105℃, lower than the softening point of the basic resin, so the selection of wax substances as the viscosity regulator is the most appropriate. In the deployment of attention to the amount of reasonable, paraffin mixed into too much or too little will affect the quality of EVA hot melt adhesive, and to the appropriate proportion of other additives, generally matched into the amount of control in about 10%.

4. Antioxidants

Colloid in melting due to high temperature oxidation decomposition, adding an appropriate amount of antioxidant can prevent the premature aging of hot melt adhesive. And under high temperature conditions, adding the right amount of antioxidant, adhesive viscosity will not change, enough to ensure the binding effect of the book. Antioxidant generally choose BHT, the effect is better, its dosage is generally controlled in 0.5% is appropriate.