How to choose the appropriate hot melt adhesive for books and magazines?

1. Melting point of hot melt adhesive for books and periodicals

The melting point is commonly referred to as the melting point in the hot melt adhesive industry. Calling the melting point is actually not very accurate. Because the melting of hot melt adhesive is within a temperature range, it is more scientifically called the melting range.

The melting point range of hot melt adhesive refers to the temperature range from the initial melting point to the final melting point, which is one of the most basic properties of hot melt adhesive.

Generally speaking, the melting range of all hot melt adhesives is between 30 ° C and 120 ° C. The melting range of low-temperature hot melt adhesive is about 30 ℃ -50 ℃, the melting range of medium temperature hot melt adhesive is about 50 ℃ -80 ℃, and the melting range of high-temperature hot melt adhesive is about 80 ℃ -110 ℃.

2、 Melt index

Melting mainly refers to the fluidity of hot melt adhesive after melting. The higher the melt index, the better the fluidity, while the lower the melt index, the worse the fluidity.

The melt index is a very important parameter outside the melting range of hot glue. It is directly related to the applicability of hot melt adhesive.

Because the fluidity of glue directly affects the glue application process, the better the fluidity, the faster the diffusion and wetting speed on the bonding surface during application. If the fluidity is poor, the spreading and wetting speed will be slower, and the glue application time will be relatively longer.

So the better the liquidity, the better the hot melt adhesive? Actually, it’s not like that. It depends on your specific adhesive material and process characteristics to make a specific choice.

3、 Working temperature and pressurization time

The biggest feature of hot melt adhesive is its short operation time and high work efficiency. The operating temperature and pressing time of hot melt adhesive for books and periodicals are essential process parameters that must be mastered during procurement. The operating temperature and pressurization time correspond to the physical and chemical parameters of hot melt adhesive melting range and melt index.

It should be noted that the working temperature of hot melt adhesive is not the value of the melting range, and is generally about 30 ℃ higher than the final melting point within the melting range. Of course, the specific temperature needs to be adjusted according to the melt index of the hot melt adhesive.

4、 High and low temperature resistance

Due to the nature of hot melt adhesive, which is a thermoplastic material, its high temperature resistance is generally poor. The hot melt adhesive with the best temperature resistance generally does not exceed 100 ℃, but its low-temperature resistance may vary depending on the material.

When purchasing hot melt adhesive, it is necessary to understand the environmental temperature limitations of your application and then choose the appropriate hot melt adhesive. This can save a lot of detours.

5、 Washability

As hot melt adhesive is commonly used for bonding clothing fabrics, its waterproof performance is usually tested.

This is because clothes usually need to be washed repeatedly. After repeated washing without opening or delamination, the product is qualified. This requires the hot melt adhesive itself to have a certain degree of waterproof performance.

6、 Solvent resistance

Solvent resistance refers to the ability of hot melt adhesive to maintain good adhesive strength in environments that are frequently exposed to solvents, ensuring that it does not crack. Solvent refers to organic chemical solvents, usually ethanol, ether, acetone, styrene, etc.

Most hot melt adhesive products have poor solvent resistance because many organic solvents themselves can dissolve the macromolecular structure of hot melt adhesive.

If you need to purchase solvent resistant hot melt adhesive and have strong adhesion to the adhesive material, you need to first screen the solvent resistant adhesive and then conduct adhesive strength testing. This will save a lot of energy.

7、 Aging resistance

When developing many materials, especially in many outdoor applications, aging resistance is a factor to consider. For this type of application, hot melt adhesive usually needs to undergo aging testing under ultraviolet light irradiation.

The aging resistance of hot melt adhesive for books and periodicals directly reflects the ability of hot melt adhesive to maintain adhesive strength after prolonged exposure to sunlight. Attention should be paid when purchasing hot melt adhesive. If your application requires prolonged outdoor exposure, do not forget to inquire about the performance of the adhesive in this regard.