Hot melt adhesive or hot melt glue is a type of thermoplastic adhesive that is solid at room temperature and becomes molten at high temperatures, adhering to surfaces that are capable of being wetted. This type of adhesive has various characteristics, which can be explained as follows:

Constituent Elements:

1. Polymer:
   - Adding polymer to hot melt adhesives provides strength and suitable flexibility to the adhesive.

2. Resin:
   - The addition of resin enhances the adhesive properties, providing high bonding strength.

3. Chemical Softener:
   - These substances control the viscosity and fluidity of the adhesive.

4. Antioxidant:
   - Antioxidants are used to protect the adhesive from deterioration during its service life.

Performance of Hot Melt Adhesives:

1. Temperature:
   - The temperature of the adhesive must be sufficiently high for the viscosity to decrease, allowing the adhesive to wet the substrate. The materials should be bonded to the substrate before the adhesive cools.

2. Attachment Surface:
   - This criterion refers to the amount of adhesive used and its connection to the secondary substrate during cooling and wetting.

3. Compression:
   - The pressure applied to prepare the substrate for the placement of the secondary surface affects the bond strength between the two layers.

Advantages of Hot Melt Adhesives:

- Long-Term Durability:
   Hot melt adhesives can adhere to various surfaces for an extended period.

- No Loss of Thickness:
   These adhesives retain their thickness when drying.

- No VOC (Volatile Organic Compounds):
   These adhesives are manufactured without the use of volatile organic compounds.

- Quick Drying:
   Hot melt adhesives generally dry quickly.

- Cost-Effective:
   These adhesives are often economical.

 Acronal Adhesive (Pressure-Sensitive Adhesive):

- Wide Application:
   Acronal adhesives are widely used in various industries, especially for paper labels, bonding foam, and cloud applications.

- Pressure-Sensitive:
   This type of adhesive is sensitive to pressure.

 Differences Between Hot Melt Adhesives and Acronal:

- Adhesion:
   Hot melt adhesives have significantly higher adhesion compared to Acronal adhesives.

- Temperature:
   Hot melt adhesives require higher temperatures for melting, whereas Acronal adhesives can exhibit adhesion even at lower temperatures.

- More Reliable Performance:
   Hot melt adhesives appear to have a more reliable performance compared to Acronal adhesives.

Conclusion:

Hot melt adhesive, also known as hot melt glue, is a thermoplastic adhesive that solidifies at room temperature and becomes molten at higher temperatures, effectively adhering to wettable surfaces. Comprising polymers, resins, chemical softeners, and antioxidants, hot melt adhesives offer flexibility, strength, and durability.

In terms of performance, the adhesive requires elevated temperatures for proper wetting and bonding to the substrate. Key factors include temperature, attachment surface, and compression strength. Hot melt adhesives exhibit long-term durability, maintain thickness during drying, lack volatile organic compounds (VOCs), dry quickly, and are cost-effective.

In contrast, Acronal adhesives, a type of pressure-sensitive adhesive, find widespread use in various industries, particularly for paper labels and bonding foam. Noteworthy differences include the superior adhesion of hot melt adhesives, their temperature requirements for melting, and a perceived more reliable overall performance compared to Acronal adhesives.